TRAY TO HOUSE A GROUP OF ELECTROCHEMICAL CELLS AND MANUFACTURING PLANT USING THE TRAY

TECHNICAL FIELD

The present invention relates to a manufacturing plant for producing electrochemical cells, in other words devices capable of converting electrical energy into chemical energy and vice versa.

The present invention further relates to a tray that can house a group of electrochemical cells to be used in such a manufacturing plant.

BACKGROUND ART

A manufacturing plant for manufacturing electrochemical cells includes an assembly section in which all the components of each electrochemical cell are assembled together to “physically construct the electrochemical cell and each electrochemical cell is filled with the electrolyte solution, and a finishing section in which each cell is subjected to charging and discharging cycles possibly interspersed with rest phases which are necessary to give the electrochemical cell the desired characteristics.

The finishing section of a known manufacturing plant includes a plurality of trays, each of which holds a group of electrochemical cells and is moved between a plurality of successive processing stations, each of which is configured to perform a certain processing operation on the electrochemical cells.

The processing stations in which the electrochemical cells are to be subjected to a charging or discharging cycle are provided, for each electrochemical cell, with two electrical power contacts (these being adapted to have charging/discharging electrical current passing through them) and two electrical measuring contacts (these being adapted to have passing through them extremely low electrical currents purely for the purpose of measuring electrical voltage). All the electrical contacts are carried by a (at least one) shared plate which is pushed (with a degree of force to ensure adequate electrical continuity) against the terminals of the electrochemical cells housed in one same tray to permit the charging or discharging cycle (which must be performed with constant control of the electrical voltage of every single electrochemical cell).

The processing stations in which the electrochemical cells are not to be subjected to a charging or discharging cycle (typically the processing stations in which the electrochemical cells are subjected to “ageing”, that is they are allowed to rest for periods of several hours) may (for the sake of simplicity and economy) not have any type of electrical connection with the electrochemical cells or may have, for each electrochemical cell, only two electrical measuring contacts (these being adapted to have passing through them extremely low electrical currents purely for the purpose of measuring electrical voltage); if present, all the electrical contacts are carried by a (at least one) shared plate which is pushed (with a degree of force to ensure adequate electrical continuity) against the terminals of the electrochemical cells housed in one same tray to permit the measurement of the electrical voltage of every single electrochemical cell.

Conventionally, operations which require a relatively long waiting time (especially ageing) are performed for a constant length of time, in other words have a predetermined duration which is always the same for all the electrochemical cells.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to provide a manufacturing plant for manufacturing electrochemical cells and a tray for electrochemical cells to be used in such a plant which make it possible to increase efficiency (this being understood to mean the total number of electrochemical cells manufactured over a long period), make it possible to reduce the number of electrochemical cells discarded, enhance safety at the plant, while being easy and inexpensive to put into practice.

The present invention provides a manufacturing plant for manufacturing electrochemical cells and a tray that can house a group of electrochemical cells for a manufacturing plant for manufacturing electrochemical cells, as claimed in the attached claims.

The claims describe embodiments of the present invention and form an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate a non-limiting embodiment thereof, in which:

• Figure 1 schematically depicts a manufacturing plant for manufacturing electrochemical cells;

• Figure 2 is a perspective view of an electrochemical cell manufactured in the manufacturing plant of Figure 1 ;

• Figure 3 is a perspective view of a tray used in a finishing section of the manufacturing plant of Figure 1 ;

• Figures 4-8 are various views of the tray of Figure 3 with some components removed;

• Figure 9 is a side view of the tray of Figure 3; • Figure 10 is an electrical diagram of a control unit of the tray of Figure 3;

• Figure 11 is a schematic view of a processing station of a finishing section of the manufacturing plant of Figure 1 ;

• Figure 12 is a schematic view of a housing of the processing station of Figure 11 ;

• Figure 13 is a perspective view of a tray used in a finishing section of the manufacturing plant of Figure 1 according to an alternative embodiment, in which a perimeter wall has been partially removed;

• Figures 14-16 are various views of the tray of Figure 13 with some components removed; and

• Figure 17 is a view from below of the tray of Figure 13 in which the base wall has been removed.

BEST MODES FOR CARRYING OUT THE INVENTION

In Figure 1 , the reference numeral 1 designates, as a whole, a manufacturing plant for manufacturing electrochemical cells 2, in other words devices capable of converting electrical energy into chemical energy and vice versa.

As shown in Figure 2, each electrochemical cell 2 includes a casing 3 which contains inside two half-elements (or half-cells) kept separate by a semi-permeable membrane. When the halfelements are suitably connected by means of an external electrical circuit, the electrons produced by the oxidation reaction that takes place in one half-element are transferred to the other, giving rise to a reduction reaction. A half-element is generally composed of a metal electrode immersed in an electrolyte solution, the latter sometimes consisting of ions of the same metal and other times of ions of another metal. Assembled to the casing 3 are two terminals 4 (a positive terminal 4 and a negative terminal 4, respectively) which allow the electrical connection of the electrochemical cell 2 to the outside world.

In the non-limiting embodiment illustrated in the attached figures, the casing 3 of each electrochemical cell 2 has a prismatic shape, in particular parallelepiped, with the two terminals 4 arranged one beside the other on the same wall. According to other embodiments which are not shown, the casing 3 may have a cylindrical shape and/or may have the two terminals 4 on opposite walls. The electrochemical cells 2 could also be of another type and have a non-rigid casing 3, for example a “pouch” type casing.

As shown in Figure 1 , the manufacturing plant 1 includes an assembly section 5 in which all the components of each electrochemical cell 2 are assembled together to “physically’ construct the electrochemical cell 2. In this section 5, each electrochemical cell 2 undergoes a filling phase in which an electrolyte solution is placed inside the cell 2, which is followed by a soaking phase in which said electrolyte solution is absorbed by the electrodes and the separator present in said electrochemical cell 2. The soaking operation generally takes a very long time and, for example, may take around ten hours for each electrochemical cell 2.

The manufacturing plant 1 also includes a finishing section 6 to which the electrochemical cells 2 leaving the section 5 are transferred. In the finishing section 6, each cell is subjected to charging and discharging cycles possibly interspersed with rest phases which are necessary to give the electrochemical cell 2 the desired characteristics.

The finishing section 6 uses a great many trays 7, each of which houses a group of electrochemical cells 2 and is moved through the entire finishing section 6 in such a way that all the electrochemical cells 2 carried by one same tray 7 are subjected together to the same processing operations throughout the finishing section 6. A tray 7 may contain for example 16-48 electrochemical cells 2: generally, when the electrochemical cells 2 are smaller, the number of electrochemical cells 2 housed in one same tray 7 increases, and vice versa.

In the exemplary embodiment illustrated in the attached figures, each tray 7 houses twenty-four electrochemical cells 2 arranged in two parallel rows.

Typically, the finishing section 6 has a plurality of processing stations S1-S9 corresponding to various processing phases. Moreover, the finishing section 6 has handling devices 8 configured to move the trays 7 between the processing stations S1-S9. Preferably (but not necessarily), the handling devices 8 comprise autonomous guided vehicles (“AGV”) which are loaded and unloaded by robots. Each vehicle is configured to receive at least one tray 7. Alternatively or in addition, the handling devices 8 may also comprise conveyors.

The finishing station 6 includes, for example, an input station S1 ‘input’) in which the electrochemical cells 2 are received, the latter then being grouped together and placed in the corresponding trays 7.

From the input station S1 , the trays 7 carrying the corresponding electrochemical cells 2 are moved to a pre-formation station S2 {pre-formation" in which each electrochemical cell 2 is subjected to a first (brief) charging-discharging cycle which may last around four hours in total.

From the pre-formation station S2, the trays 7 carrying the corresponding electrochemical cells 2 are moved to an ageing station S3 (“RT ageing") in which each electrochemical cell 2 is allowed to rest, for example for around 12 hours.

From the RT ageing station S3, the trays 7 carrying the corresponding electrochemical cells 2 are moved to a formation station S4 {‘formation”) in which each electrochemical cell 2 is subjected to a second (lengthy) charging-discharging cycle which may, for example, last around sixteen hours in total.

From the formation station S4, the trays 7 carrying the corresponding electrochemical cells 2 are moved to a degasification station S5 (“degas”) in which the gases generated internally are purged from each electrochemical cell 2, by removing a provisional cap that was previously applied during the filling phase. Once the gases generated internally have been purged from the electrochemical cell 2, the latter is sealed using a permanent cap which must not be removed any more, and which may include a safety valve which opens when the pressure inside the casing 3 exceeds a pressure threshold (following thermal drift which results in “venting").

From the degas station S5, the trays 7 carrying the corresponding electrochemical cells 2 are moved to an ageing station 6 (“HT ageing") in which each electrochemical cell 2 is allowed to rest for a number of ageing sessions, for example three, which may each last for dozens or hundreds of hours. The open circuit voltage (“OCV”) of each electrochemical cell 2 is measured for example at the end of each session.

From the HT ageing station S6, the trays 7 carrying the corresponding electrochemical cells 2 are moved to a grading station S7 ‘grading"). At this station, each electrochemical cell 2 is subjected to a test on the basis of which its performance is graded, and it is assigned to a category, the cells in each category having substantially homogeneous performance.

From the grading station S7, the trays 7 carrying the corresponding electrochemical cells 2 are moved to a sorting station S8 ‘sorting") in which the electrochemical cells 2 are redistributed in the trays 7 in such a way as to constitute homogeneous groups of electrochemical cells 2, in other words groups in which all the electrochemical cells 2 have substantially the same level of performance. In the sorting station S8, the electrochemical cells 2 may also be subjected to additional checks, for example checks on their leak tightness (this meaning absolutely no loss of electrolyte solution).

From the sorting station S8, the trays 7 carrying the corresponding electrochemical cells 2 are moved to an output station S9 {‘output’). The manufacturing process is complete and the electrochemical cells 2 leave the finishing section 6 and are then taken out of the trays 7.

A manufacturing plant according to the present invention may include sections and/or processing stations that are different and/or in a different order to what has been described above.

The manufacturing plant 1 includes a central processing unit 34 configured to oversee the operation of the manufacturing plant 1 (and in particular to oversee the operation of the finishing section 6 of the manufacturing plant 1).

As shown in Figures 3 and 4, each tray 7 of prismatic shape includes a base wall 9. The tray 7 further includes a plurality of seats 10, each of which can receive and hold a corresponding electrochemical cell 2, which is arranged with the two terminals 4 oriented upwards (to be specific, there are twelve seats 10 arranged in two rows). Preferably, the seats 10 are made in the base wall 9.

Extending from the base wall 9 are two side walls 11 (in other words two shoulders) which laterally delimit the space in which the electrochemical cells 2 are housed and support a top wall 12 which is parallel and opposite to the base wall 9.

According to a preferred embodiment, the side walls 11 are stably connected to the top wall 12 and therefore constitute, together with the top wall 12, a “cover” which may be attached to and removed from the base wall 9 and is taken off to place or remove the electrochemical cells 2 in/from the seats 10 in the base wall 9. In other words, the tray 7 is opened to allow access to the seats 10 in the base wall 9 by disconnecting the side walls 11 (which remain stably attached to the top wall 12) from the base wall 9.

The cover is thus U-shaped and includes the top wall 12 opposite the base wall 9 and the two side walls 11 which protrude from the top wall 12 in a cantilever way and may be connected to the base wall 9.

According to a preferred embodiment illustrated in the attached figures, each tray 7 is open to the front and to the rear (with reference to the arrangement shown in Figure 3 for example) in such a way as to allow ample natural ventilation of the space in which the electrochemical cells 2 are housed. In other words, each tray 7 of prismatic shape is missing two walls to allow natural ventilation of the space in which the electrochemical cells 2 are housed, in other words to place a space for housing the electrochemical cells 2 in stable communication with the outside, keeping the ambient conditions inside and outside the tray 7 substantially uniform.

According to the preferred embodiment illustrated in Figures 5-8, each tray 7 includes a plate 13 which is mounted on the top wall 12 (that is, on the inside of the top wall 12 so as to be next to the electrochemical cells 2) and is provided with a plurality of electrical measuring contacts 14. The plate 13 is positioned in such a way that each of the plurality of electrical measuring contacts 14 is arranged in correspondence with a terminal 4 of a respective electrochemical cell 2. More specifically, the plate 13 has, for each electrochemical cell 2, two electrical measuring contacts 14 (these being adapted to have passing through them extremely low electrical currents for the purpose of measuring electrical voltage or, in some cases, impedance) which are arranged in correspondence with the terminals 4 of the electrochemical cell 2 (the electrical measuring contacts 14 can be seen in Figure 8). When the top wall 12 is mounted on the tray 7 (in other words when the two side walls 11 are secured to the base wall 9), the electrical measuring contacts 14 are pushed (with a degree of elastic force to ensure adequate electrical continuity) against the corresponding terminals 4 of the electrochemical cells 2. Thus, the two terminals 4 of each electrochemical cell 2 are in continuous electrical contact with two respective electrical measuring contacts 14; in other words, for the entire time for which each electrochemical cell 2 is carried by a tray 7, its terminals 4 are continuously electrically connected to two respective electrical measuring contacts 14.

The plate 13 has a plurality of through holes 15, more specifically, for each electrochemical cell 2, the plate 13 has two through holes 15 (shown in Figures 5, 6 and 7) which are arranged in correspondence with the terminals 4 of the electrochemical cell 2. Likewise, for each electrochemical cell 2, the top wall 12 of each tray 7 has two through holes 16 (shown in Figure 3) which are aligned (coaxial) with the respective through holes 15 in the plate 13 and are therefore arranged in correspondence with the terminals 4 of the respective electrochemical cell 2. When the top wall 12 is mounted on the tray 7 (in other words when the two side walls 11 are secured to the base wall 9), the terminals 4 of each electrochemical cell 2 are accessible from the outside, i.e. from outside the tray 7, through the respective through holes 15 and 16. Thus, through the respective through holes 15 and 16, electrical power contacts 17 (shown schematically in Figure 12 and adapted to have, for example, electrical charging/discharging current passing through them) may be inserted through the top wall 12 of the tray 7 so as to come into contact with the terminals 4 of the electrochemical cells 2 in the processing stations S in which it is necessary to apply current of significant magnitude, as in the formation station S4.

In other words, the electrical measuring contacts 14 of the plate 13 of each tray 7 are always in contact with the terminals 4 of the respective electrochemical cells 2, whereas the electrical power contacts 17 are brought into contact with the terminals 4 of the respective electrochemical cells 2 through the respective through holes 15 and 16 only when necessary (in other words only in the processing stations S in which it is necessary to apply current of significant magnitude). Preferably, the through holes 15 and 16 are (slightly) off-centre with respect to the terminals 4 of the respective electrochemical cells 2 and the electrical measuring contacts 14 are (slightly) off-centre (in the opposite direction) with respect to the terminals 4 of the respective electrochemical cells 2 in such a way that where necessary, both an electrical measuring contact 14 and an electrical power contact 17 may be in contact with one same terminal 4 of a respective electrochemical cell 2 without interfering with one another (obviously, the electrical power contact 17 is substantially bigger than the electrical measuring contact 14).

In other words, for each electrochemical cell 2 there are two electrical power contacts 17, which are separate and independent from the electrical measuring contacts 14 and are connected to the terminals 4 of the electrochemical cell 2 only when it is necessary to apply significant current to the electrochemical cell 2 as in the case of the formation and grading stations. The electrical power contacts 17 have a large size (and are therefore not subject to particular mechanical wear) and experience high electrical current intensities (hence are capable of self-eliminating surface oxidation). The electrical power contacts 17 are external to and independent of the tray 7 and the tray 7 thus has through holes 15 and 16 for the passage of the external electrical power contacts 17.

It is important to note that, when the electrical power contacts 17 are present, voltage measures could theoretically be taken using only these electrical power contacts 17. However, the electrical measuring contacts 14 are still necessary to obtain a sufficiently accurate measurement. In this case, four-point measuring techniques are used, which make use of all four electrical contacts 14 and 17.

Each tray 7 includes at least one measuring instrument 18 or 22 configured to measure a physical quantity of the electrochemical cells 2 housed in the tray 7.

Such a quantity may concern for example a temperature in the case where the measuring instrument comprises one or more temperature sensors 18 and/or an electrical voltage in the case where the measuring instrument comprises a voltmeter 22. The measuring instrument 18 or 22 outputs measures correlated to the measured quantity of the electrochemical cells 2.

According to the preferred embodiment of Figure 5-8, temperature sensors 18 which interact with the electrochemical cells 2 to detect the temperature of these cells are attached to the plate 13 of each tray 7. More specifically, each temperature sensor 18 is placed under conditions of low thermal impedance with respect to the casing 3 of a corresponding electrochemical cell 2, in particular in contact with (or in close proximity to) a side wall of the casing 3, so as to measure in real time the external temperature of the casing 3. According to a preferred embodiment, the plate 13 of each tray 7 has a series of support elements 19 which protrude downwards (in other words towards the base wall 9) from said plate 13 in a cantilever way, are arranged in such a way as to be inserted between two electrochemical cells 2 placed side by side, and each support two temperature sensors 18. In other words, each support element 19 has a prismatic shape, is attached to the plate 13, is arranged perpendicularly to the plate 13, and supports, on two opposite faces, two temperature sensors 18, each of which is placed, in the embodiment illustrated, in contact with (or at least in close proximity to) the casing 3 of a corresponding electrochemical cell 2.

As shown in Figures 4 and 7, each tray 7 includes a control unit 20 which is electrically connected to the electrical measuring contacts 14 and to the temperature sensors 18. To this end, the plate

13 is equipped with electrical connections which connect the electrical measuring contacts 14 and the temperature sensors 18 to the control unit 20. Preferably, the control unit 20 is arranged in a cavity 21 made in one of the side walls 11 .

In other words, according to the preferred embodiment, each tray 7 includes a standard base (the base wall 9) which has the seats 10 for the individual electrochemical cells 2 and is passive (in other words is devoid of electronic instrumentation) and an “intelligent” cover (consisting of the walls 11 and 12) which is placed on top of the passive base and supports the electrical measuring contacts 14, the temperature sensors 18, and the control unit 20.

More specifically, the cover supports the plate 13 provided with the electrical measuring contacts

14 and has the through holes 16 aligned with the through holes 15 in the plate 13, which allow the electrical power contacts 17 to come, from the outside, into contact with the terminals 4 of the electrochemical cells 2. The cover also houses the measuring instrument or instruments 18 and/or 22, the control unit 20 and a first communication device 32 or 33 which will be described below.

The support elements 19 which support the temperature sensors 18 are also connected to the cover.

One of the side walls 11 has the cavity 21 which houses the control unit 20.

As shown schematically in Figure 10, the control unit 20 includes the abovementioned voltmeter 22 which, by means of a multiplexer 23 (designated in Figure 10 also with the label “INPUT MUX”) can be connected selectively to each pair of electrical measuring contacts 14 for measuring the voltage between the electrical measuring contacts 14 (in other words between the terminals 4 of the corresponding electrochemical cell 2). Moreover, the control unit 20 includes a further multiplexer 24 (designated in Figure 10 also with the label “INPUT MUX’ which is connected to the temperature sensors 18.

The control unit 20 includes a processor 25 (designated in Figure 10 also with the label “CPU") and a series of analogue/digital converters 26 (designated in Figure 10 also with the label “ADC") which connect the two multiplexers 23 and 24 to the processor 25 (in other words which indirectly connect the electrical measuring contacts 14 and the temperature sensors 18 to the processor 25).

The processor 25 is configured to cyclically read the signals sent by the temperature sensors 18 and the voltmeter 22 in such a way as to determine, at a predetermined frequency (for example every 2-10 minutes), the electrical voltage and the external temperature of each electrochemical cell 2 carried by the tray 7. Generally, the frequency at which the electrical voltage and the external temperature of each electrochemical cell 2 is read increases when the electrochemical cell 2 undergoes charging or discharging (in other words is active) and decreases when the electrochemical cell 2 is allowed to rest (in other words is passive).

Each tray 7 includes an electrical connector 28 (shown in Figures 3 and 9), configured to establish an electrical connection through which it receives electrical energy from the outside, and its own DC electrical circuit 27 (shown schematically in Figure 10) which receives the electrical power supply from the electrical connector 28. According to a preferred embodiment, the electrical connector 28 has spring-loaded contacts or is configured to be coupled to spring-loaded contacts.

The control unit 20 includes an electrical energy storage device 29 (designated in Figure 10 also with the name “SUPERCAP’) which provides the necessary power supply and is charged by the electrical circuit 27. The storage device 29 may also be connected to a contactless charging device 30 which is used as an alternative to the electrical connector 28. In other words, according to one possible embodiment illustrated in Figure 10, in addition to the electrical connector 28 which provides a physical connection for receiving electrical energy from the outside, there could also be the contactless charging device 30, which does not provide a physical connection (but merely a proximity connection) for receiving electrical energy from the outside (generally, the electrical connector 28 is used as an alternative to the contactless charging device 30).

The contactless charging device 30 is of known type and may consist for example of a contactless power transmission system which generally includes an air transformer with the primary winding arranged in a component attached to the processing station S and the secondary winding arranged in the tray 7. Other types of power transmission systems are also possible.

In the embodiment illustrated in Figure 10, both the electrical connector 28 and the contactless charging device 30 are present, these being used as alternatives to one another. According to a different embodiment not illustrated, only one out of the electrical connector 28 and the contactless charging device 30 is present.

According to a preferred embodiment, the tray 7 has no battery, is configured to receive electrical energy from the outside when it is positioned at each of the processing stations S and comprises at least one capacitor which supplies electrical energy to the tray 7 when the latter is not positioned at a processing station S. Preferably, the storage device 29 comprises a high-capacity capacitor, or supercapacitor, which, according to the preferred embodiment, is charged when the tray 7 is positioned at one of the processing stations S. The storage device 29 therefore has a smaller storage capacity (substantially sufficient to deliver the power necessary for operation of the control unit 20 for limited periods during the transfer of the tray 7 between stations S1 -S10).

If the chemical battery is dispensed with in the storage device 29, it is necessary to continuously supply the tray 7 with power (through the electrical connector 28 and/or the contactless charging device 30) when the tray 7 is at a processing station S. However, dispensing with the chemical battery in the storage device 29 does have many advantages and simplifies operation since, unlike supercapacitors, chemical batteries require periodic maintenance, are subject to wear and ageing, cannot be “abandoned’ if stored for lengthy periods, are subject to strict legal requirements when transported, and are liable to break down. Furthermore, in addition to having no regulatory requirements for storage and transport, supercapacitors can withstand much higher charging and discharging currents than chemical batteries.

According to an alternative embodiment, the storage device 29 may however include a battery, for example a chemical battery which, although having the limitations described above, has a much higher storage capacity (sufficient to deliver the power necessary for operation of the control unit 20 for much longer periods).

According to a preferred embodiment, the control unit 20 includes a non-volatile memory 31 (designated in Figure 10 also with the label “RETENTIVE MEMORY’) in which the processor 25 cyclically writes the readings from the temperature sensors 18 and the voltmeter 22.

Each tray 7 further includes the abovementioned first communication device 32 or 33 configured to transmit to the central processing unit 34 the measures taken by the measuring instrument 18 or 22.

This first communication device 32 or 33 may communicate via cable or wirelessly.

According to the preferred embodiment, the first communication device 32 or 33 uses wireless communication, preferably close proximity communication. More specifically, the first communication device 32 or 33 uses optical communication (33) or radio communication (32) as described in more detail below.

As shown in Figure 10, the first communication device forms part of the control unit 20 and includes a radio wireless communication device 32 (designated in Figure 10 also with the label “RADIO MODULE") which uses radiofrequency transmission technology and is connected to the processor 25.

As shown in Figure 10, the first communication device forming part of the control unit 20 also includes an IR wireless communication device 33 (designated in Figure 10 also with the label “IR MODULE”) which uses optical transmission technology (specifically infrared) and is also connected to the processor 25.

In the embodiment illustrated in Figure 10, both wireless communication devices 32 and 33 are present, these generally being used as alternatives to one another. According to a different embodiment not illustrated, only one out of the two wireless communication devices 32 and 33 is present.

To reduce costs and consumption, the communication generated by the first communication device 32 or 33 may be one-way, only from the tray 7 to the central processing unit 34 (shown schematically in Figure 11).

The radio wireless communication device 32 preferably uses close proximity radio communication (for example via NFC or RFID): this is a very short range and low power solution which considerably reduces the problem of interference generated by a high number of elements trying to communicate in the same environment.

The IR wireless communication device 33 uses close proximity optical communication technology which does not generate electromagnetic pollution and is completely impervious to any electromagnetic pollution that may be present. Furthermore, unlike radio communication, optical communication does not require any type of authorization.

The control unit 20 is configured to communicate the measures detected by the temperature sensors 18 and the voltmeter 22 (possibly temporarily stored in the memory 31) to the central processing unit 34 (shown schematically in Figure 11) of the finishing section 6, cyclically or, for example, on request from the central processing unit 34.

In particular, the manufacturing plant 1 includes a plurality of second communication devices 35 configured to dialogue with the first communication device 32 or 33 of each tray 7. As shown in Figure 11, each processing station S includes a communication device 35 which dialogues with the communication device 32 or 33 of each tray 7 to receive, for example cyclically or continuously, the corresponding measures taken by the temperature sensors 18 and the voltmeter 22. Figure 11 shows a communication device 35 for each tray 7 such that the communication device 35 may be in close proximity to the respective tray 7. Alternatively, one same communication device 35 could dialogue simultaneously with several trays 7.

According to one possible embodiment, the second communication devices 35 which dialogue with the first communication devices 32 or 33 of the trays 7 may also be fitted on board vehicles (generally autonomous guided vehicles, or “AGV”) which move the trays 7 between the processing stations S. According to another embodiment, especially in the case where the trays 7 are moved between the processing stations S by means of conveyors, the communication devices 35 which dialogue with the communication devices 32 or 33 of the trays 7 may be fitted in gates through which the trays 7 pass and which are arranged at suitable distances along the path.

The manufacturing plant 1 further includes a plurality of concentrator devices 36 configured to receive the measures from the first communication device 32 or 33 of each tray 7 and to send data to the central processing unit (34). Data refers to what is output by each concentrator 36 after having performed the operations it is configured to carry out.

According to the preferred embodiment, each concentrator 36 is connected (normally via cable) to a plurality of corresponding communication devices 35 so as to receive and sort (and possibly pre-process) the information, in particular the measures, coming from said communication devices 35 and hence send to the central processing unit 34 packets of information in the form of data.

By way of example, there could be a concentrator device 36 for every 10, 100 or 1000 trays 7 (in other words a single concentrator device 36 interacting with 10, 100 or 1000 trays 7). The concentrator devices 36 may communicate with the central processing unit 34 by means of a cable or wireless connection, in a manner known per se.

The function of the concentrator devices 36 is very important since it makes it possible to manage the presence of a very high number of trays 7 (up to hundreds of thousands of trays 7) communicating wirelessly: by virtue of the presence of the concentrator devices 36 the wireless communication takes place over very limited distances and hence the power of the wireless communication may be very low without the risk of interference and of excessive electromagnetic pollution (in the case of radiofrequency communication). In other words only through the presence of the concentrator devices 36 is it possible to manage, from a practical point of view and with relatively limited costs and technical complexity, the communications of a very high number of trays 7 (up to hundreds of thousands of trays 7).

In other words, each concentrator device 36 constitutes a node of a communication network which allows each tray 7 to transmit to the central processing unit 34 the measures taken by the measuring instrument 18 or 22.

The use of the concentrator devices 36 therefore reduces the number of network nodes which have to connect all the trays 7. In other words, the presence of the concentrator devices 36 makes it possible to add more trays 7 under the same node of the communication network, reducing the complexity of the network while at the same time facilitating scalability of the manufacturing plant 1. Without the concentrator devices 36, the network would have hundreds of thousands of nodes and it would thus be difficult to put into practice and manage from the point of view of costs. The concentrator devices 36 may also be used in processing plants according to an alternative embodiment, with trays 7 which communicate via cable rather than wirelessly, retaining the advantages in terms of reduction of the number of network nodes.

According to one possible embodiment, the concentrator devices 36 only collect and packet information, which is transmitted substantially as received from the trays 7 to the central processing unit 34. According to an alternative embodiment, the concentrator devices 36 additionally ensure processing (more or less complete) of the information received from the trays 7 (in this case, the processor 25 of the control unit 20 of the trays 7 may be simplified and/or the processing performed by the central processing unit 34 may be alleviated).

In other words, in a “Gigafactoiy there may be hundreds of thousands of trays 7 active at the same time and therefore, without adequate arrangements, there would be an extremely high risk of not having the necessary communication channels to cope with the traffic of data, as well as a problem of electromagnetic interference since all the trays 7 have to cyclically communicate with the central processing unit 34. To limit the complexity of the situation, the range of communication generated by the communication devices 32 and 33 of the trays 7 is minimized (in other words the range of communication is reduced so as to reduce interference), the number of communication devices 35 in the processing stations S and the number of concentrator devices 36 thus having to be increased. Therefore, the radio communication devices 32 of the trays 7 use close proximity radio devices (NFC and RFID) while the IR communication devices 33 of the trays 7 use an optical solution (which, among other things, is not subject to radio authorization obligations).

Each tray 7 could use communication which is one-way only as output (in other words only from the tray 7 to the central processing unit 34) and asynchronous (hence with a timestamp). Consequently, if a tray 7 does not manage to transmit a communication in real time but transmits the communication with some delay (for example because the tray 7 is in transit between two successive processing stations S) this does not cause any problems (the cycle of formation of an electrochemical cell 2 takes a very long time, generally requiring several days and thus it is not detrimental to process data from an electrochemical cell 2 with a time delay of some minutes).

Each processing station S includes a plurality of references 37, each of which is configured to define the position of a respective tray 7. These references may be produced for example in the form of housings.

Figure 11 schematically shows a processing station S in which there are a number of references 37, each of which is able to receive a respective tray 7. In correspondence with each reference 37 there is a communication device 35 which dialogues with the communication device 32 or 33 of the tray 7.

Each reference 37 is configured to define the position of the respective tray 7 in such a way that the first communication device 32 or 33 of the tray 7 faces the respective second communication device 35 positioned at the processing station S.

In correspondence with each reference 37 there is also an electrical connector 38 which connects to the electrical connector 28 of the tray 7 so as to provide the electrical power supply to the tray 7 (as stated above, the electrical connectors 28 and 38 preferably use spring-loaded contacts). As an alternative or in addition to the electrical connector 38, there may be a wireless charging system which works with the contactless charging device 30 mentioned above.

More specifically, one of the electrical connectors 28 and 38 has movable spring-loaded contacts which protrude outwards and the other has fixed locations (for example made on a printed circuit) against which the spring-loaded contacts are pressed. According to the preferred embodiment, the electrical connector 28 has the fixed locations while the electrical connector 38 has the spring- loaded contacts. The use of electrical connectors 28 and 38 which use spring-loaded contacts makes it possible to bring down the cost of the electrical connectors 28 and 38 while ensuring optimal reliability. It also makes it possible to ensure a good electrical connection even when the connectors 28 and 38 are not perfectly centred. Furthermore, in the event of damage or wear, the replacement of the electrical connector 38 having spring-loaded contacts is quick and inexpensive.

According to a possible embodiment illustrated in Figure 10, the control unit 20 of each tray 7 also includes an accelerometer 39 (for example a triaxial accelerometer designated in Figure 10 also with the label “ACCELEROMETER’) capable of detecting displacements, collisions, and possibly tilting of the tray 7. In other words, the accelerometer 39 is configured to measure an (at least one) acceleration experienced by the tray 7 and the control unit 20 is configured to receive the acceleration measure from the accelerometer 39 and to generate an event (to be stored or to be sent to the central processing unit 34) if the absolute value of the acceleration measure is higher than a predetermined threshold.

The accelerometer 39 makes it possible to increase the capacity for self-diagnosis, enabling the tray 7 to recognize if it is stopped or in motion, if it has accelerated beyond a predetermined safety threshold (indicating a collision or a fall), and if its position is not oriented correctly. The recognition of such situations may trigger appropriate action, or may simply be recorded in local memory, together with the recorded voltage and temperature measures. In particular, the additional information gathered by the accelerometer 39 may help to obtain better control over the manufacturing process, making it possible to detect events not immediately identified, especially in a situation of high automation with no supervision by an operator.

The tray 7 may further be equipped with an optional geolocation function (implemented with the aid of the wireless communication for example) making it possible to locate the position of each tray 7 within the manufacturing plant.

To sum up, to obtain continuous monitoring of all the electrochemical cells 2 of a tray 7, a pair of electrical measuring contacts 14 which are constantly connected to the two terminals 4 of the corresponding electrochemical cell 2 is arranged in each seat 10 of the tray 7. Moreover, each seat 10 of the tray 7 may have a temperature sensor 18 in a suitable position, for example on an outer wall of the casing 3 of the electrochemical cell 2, for accurately and efficiently measuring the temperature of said electrochemical cell 2. Each tray 7 includes the control unit 20 which acquires, processes and records ‘logging’’) the signals supplied by the temperature sensors 18 and the voltmeter 22. It is important to point out that if the intelligence (in this case provided by the control unit 20) is linked to an individual tray 7, the relevant maintenance is simplified: if a tray 7 is worn or damaged, maintenance can be performed only on the worn or damaged tray 7, which is temporarily withdrawn from the manufacturing cycle.

Each tray 7 has a small number (a few dozen) seats 10 and thus houses a small number of electrochemical cells 2 which are thus all arranged quite close to one another: it is thus reasonable to expect all the electrochemical cells 2 of one same tray 7 to behave in the same way (in other words, they complete the processing phase, for example the ageing phase, at more or less the same time). Moreover, a tray 7 with a limited number of electrochemical cells 2 allows good homogeneity in terms of the ageing time of the electrochemical cells 2 carried by said tray 7.

It is important to note that continuous monitoring of the electrochemical cells 2 does not necessarily require the use of high electric current, since its purpose is not to fully check all the parameters of the electrochemical cells 2 but to take measures at regular intervals of some of the parameters of the electrochemical cells 2 so as to assess their progress over a relatively long period (around tens of hours). Therefore, the measuring instruments of the individual trays 7 (in other words the temperature sensors 18 and the voltmeters 22) may be relatively simple. On the other hand, the measures taken for the “grading" operations in the grading station S7 require precise checks on a greater number of parameters of the electrochemical cells 2 and the use of higher electrical test currents. The grading station S7 may therefore include more complex (and more expensive) measuring instruments.

The finishing section 6 is optimized if the part for electrical connection with the electrochemical cells 2 is divided into power connections and measuring connections (signals). According to the preferred embodiment, each electrochemical cell 2 requires two electrical power contacts 17 and two electrical measuring contacts 14 so that it can be subjected to the formation and grading processes properly. Again according to the preferred embodiment, in the other processes that take place in the finishing section 6 the power connections may not be needed. Since the electrical measuring contacts 14 are more critical than the electrical power contacts 17 from the viewpoint of reliability, the electrical measuring contacts 14 are “permanent and rigidly secured to the tray 7 in such a way that the connection is made once for all the processes that take place in the finishing section 6. Taking advantage of the presence of these electrical measuring contacts 14 on board the tray 7 it is advantageous to have on board said tray 7 voltage, and possibly temperature, measuring electronics that will monitor every change experienced by each electrochemical cell 2: these electronics, powered by the storage device 29 (which is charged during the operations in which the tray 7 is connected to a processing station S), may communicate via the first communication device 32 and 33 to supply information necessary to flag up an anomaly or attainment of the asymptotic conditions for all the electrochemical cells 2 of the tray 7.

In use, it is not necessary to wait a predetermined standard period of time before moving a tray 7 from a given processing station S to the next, but the tray 7 may be moved on to the next processing station S when the measured voltage, and where applicable temperature, of every single electrochemical cell 2 carried by the tray 7 indicates that processing has been completed on every single electrochemical cell 2.

In any event, process monitoring is particularly detailed and allows prompt removal from the manufacturing process of any electrochemical cell 2 which is defective or poses a fire hazard, thereby saving further time and resources in the control of electrochemical cells 2 that would have to be discarded anyway and helping to enhance the safety of the plant.

According to one possible embodiment, provision may be made to carry out cleaning cycles of the electrical measuring contacts 14 periodically by flowing electric current with a predetermined intensity, more specifically an intensity which is sufficiently high to generate a cleaning effect (in other words the elimination of surface oxidation), and of a magnitude such as not to alter the state of charging of the electrochemical cells 2 housed inside the tray 7. According to the preferred embodiment, the cleaning cycle for the electrical measuring contacts 14 is performed by the control unit 20.

The tray 7 according to the present invention may also be without the temperature sensors 18 described and the associated part of the electronics to which these sensors relate.

The embodiments described herein may be combined with one another without departing from the scope of protection of the present invention.

The specific advantages mentioned above resulting, inter alia, from the presence of the concentrator devices 36, and/or the close proximity wireless transmission devices 32 and 33 and/or the possibility of doing without a battery on board the trays 7, are combined with those offered by a finishing section of a manufacturing plant which uses a tray for groups of electrochemical cells equipped with electrical measuring contacts like that described above.

The finishing section 6 in fact makes it possible to considerably reduce the average duration of the manufacturing cycle, since by monitoring the actual status of every single electrochemical cell 2 it is possible to complete the various processing phases not at the end of predetermined time periods (which must be sufficiently long to take account of worst case scenarios, i.e. the slowest or longest processing process) as in other known solutions, but when the electrochemical cells 2 have actually attained the desired status.

The finishing section 6 also offers effective fire prevention (arising from potentially destructive thermal drift in an electrochemical cell 2) through prompt detection of a sudden increase or anomalous pattern in temperature or a sharp fall in voltage in each electrochemical cell 2.

The finishing section 6 also makes it possible to improve the measurement of voltage through the ability to take account of the actual temperature of each electrochemical cell 2 and not a generic and less accurate ambient temperature reading.

The finishing section 6 makes it possible to exclude from the manufacturing process, at an early stage, any electrochemical cells 2 that deviate from the standard, thus preventing further processing being carried out on those electrochemical cells 2 only for them to be subsequently discarded at the end of the manufacturing process. In other words, the continuous monitoring of the electrochemical cells 2 also makes it possible to identify, at an early stage, any defective electrochemical cells 2 which are thus removed from the manufacturing process in advance (in other words well before the final control). This results in a manufacturing process which is not only particularly efficient but also very safe since a defective electrochemical cell 2 that remains in the manufacturing process can more easily give rise to problems (loss of liquid or indeed thermal drift with the consequent fire hazard).

The finishing section 6 clearly simplifies tracking of the individual electrochemical cells 2, as each electrochemical cell 2 is inserted in a given seat 10 of a predetermined tray 7 in the input station S1 and remains in that position throughout all the processes that take place in the finishing section 6.

In other words, according to some known conventional solutions, checks on the electrical and thermal parameters of the electrochemical cells 2 are performed only at predefined, infrequent check points, whereas the approach offered by the finishing section 6 allows continuous monitoring of the electrochemical cells 2, both to determine when ageing can be brought to an end and to identify any defective electrochemical cells 2 at an early stage.

The present invention applied to a manufacturing plant 1 like that described, and more specifically a plant comprising the finishing section 6 illustrated, makes it possible to further enhance the efficiency of the manufacturing plant 1 , to simplify the management not only of individual trays but also on a centralized level, and to ensure excellent flexibility and adaptability vis-a-vis the different types of electrochemical cells processed at various times.

Embodiments other than that described and illustrated above are included within the scope of the present invention.

For example, if the shape and/or arrangement of the terminals of the electrochemical cells 2 differs from that shown in Figure 2, the tray 7 will have a different configuration to provide appropriate housing and contact arrangements for said electrochemical cells 2.

According to another embodiment, the tray 7 also has a different configuration, for example the plate 13 comprising the measuring contacts 14 may be arranged in correspondence with the base wall 9 and/or in correspondence with other walls of the tray 7, with the arrangement of the electrochemical cells 2 being adapted accordingly.

Figures 13-17 show a possible alternative configuration of the tray 7 according to the present invention; elements in common with the previous figures (1-12) are given the same reference numerals.

The tray 7 includes a base wall 9 provided with seats 10 for housing the electrochemical cells 2, four perimeter walls perpendicular to the base wall and a top wall 43 closing the tray.

More specifically, the tray 7 includes a first 40 wall, a perimeter wall in the embodiment shown, which is substantially perpendicular to the base wall 9 and in correspondence with which the plate 13 including the electrical measuring contacts 14 (not shown in the figures) is arranged, and a second 41 wall, also a perimeter wall in the embodiment shown, which is substantially perpendicular to the base wall 9 opposite the first 40 wall, and in correspondence with which an additional plate 13 also provided with electrical measuring contacts 14 is arranged. The seats 10 are arranged in two rows aligned in a direction substantially parallel to the first 40 wall and to the second 41 wall. The electrochemical cells 2 housed in the respective seats 10 of each row have both the terminals 4 oriented towards the first 40 wall and the second 41 wall, respectively.

The tray 7 includes two additional 42 walls, also perimeter walls, which are substantially perpendicular to the first 40 wall and to the second 41 wall. As shown in the figures, the cavity 21 which houses the control unit 20 is arranged in correspondence with one of said additional 42 walls.

The tray shown in Figures 13-17 thus has a closed parallelepiped shape on at least five sides. The presence, on the sixth side, of the removable top wall 43 makes it possible to insert the electrochemical cells 2 in the tray 7 from above and to close the tray 7 once they have been inserted.

According to a preferred embodiment, shown for example in Figures 16 and 17, to prevent the insertion of the electrochemical cells 2 from damaging the electrical measuring contacts 14, the seats 10 are configured in such a way as to house the respective electrochemical cells 2 with a degree of play or predetermined clearance, in other words are dimensioned in such a way as to provide a space for housing the individual cell which is slightly greater than the dimensions of said cell, thereby leaving a free space between the electrochemical cells 2 and the perimeter walls of the tray 7. Thus, the electrochemical cells 2 may be inserted in the tray 7 and positioned in the respective seats 10 in such a way that a safety distance is maintained between the terminals 4 of the electrochemical cells 2 and the electrical measuring contacts 14 equipping the plate 13 arranged in correspondence with the respective perimeter wall. This distance, however small, prevents collisions between the terminals 4 of the electrochemical cells 2 and the electrical measuring contacts 14 at the time of insertion of the electrochemical cells 2.

There is also a positioning mechanism 44 (the components of which can be seen in part in Figure 16 and in part in Figure 17) for positioning the electrochemical cells 2 once they have been inserted in the respective seats 10 inside the tray 7.

The positioning mechanism 44 includes for example a rack and pinion device with a toothed bar 45, placed between the two rows of electrochemical cells 2 and parallel to the first 40 wall and to the second 41 wall, which engages with a series of gearwheels 46, for example one for each electrochemical cell 2. Each gearwheel 46 is connected to an eccentric 47, for example a cam, visible in Figure 17, configured to engage in turn with a respective electrochemical cell 2. When placed in rotation, each cam 47 comes into contact with - and applies a thrust to - a respective electrochemical cell 2 and gives the latter a linear motion in the direction towards the respective plates 13 until the terminals 4 of the electrochemical cells 2 come into engagement with the electrical measuring contacts 14.

To prevent the electrochemical cells 2 from being damaged, for example due to rubbing, during the movement towards the walls, it is possible to provide rolling elements, such as rollers (not shown in the figure) between the bottom surface of each electrochemical cell 2 and the respective seat 10.

Alternative systems, for example sliding elements, which allow the electrochemical cells 2 to move with zero or noticeably reduced friction, are also possible.

According to an alternative embodiment it is possible to provide a positioning mechanism 44 wherein, once inserted in the respective seats 10, the electrochemical cells 2 stay in place and it is the wall in correspondence with which the plate 13 provided with the electrical measuring contacts 14 is arranged that moves towards the electrochemical cells 2 until the electrical measuring contacts 14 come to couple with the terminals of the electrochemical cells 2. The movement of the wall with the plate 13 comes from the mechanism comprising the rack and the cams described above. In this case, each cam 47 engages with a corresponding portion of the wall carrying the plate 13 which, thanks to the presence of guides, or other sliding mechanisms, may move in translation towards the electrochemical cells (2).

It is also possible to produce the positioning mechanism 44 in such a way that the electrochemical cells 2 and the wall with the plate 13 move towards one another.

Positioning mechanisms that are different to those illustrated are also possible.

Preferably, the base wall 9 of the tray 7 has an opening which, as well as reducing the overall weight of the tray 7, promotes ventilation inside the tray 7, as can be seen in Figure 15.

Further embodiments of the present invention, not shown in the figures, are possible.

For example it is possible for the tray 7 not to be closed on one or more sides (in other words not to have some or all of the perimeter walls) or at the top (in other words not to have the top wall 43).

According to one possible embodiment, the tray may comprise for example only the base wall 9 and a single wall, perpendicular to the base wall 9 and provided with the plate 13, for example the first 40 wall. The first 40 wall may constitute one of the perimeter walls of the tray 7 or be placed in an intermediate position with respect to the sides of the tray 7.

According to another embodiment, the tray 7 includes two walls perpendicular to the base wall 9 and both provided with the plate 13, for example the first 40 wall and the second 41 wall. The first 40 wall and the second 41 wall may be opposite one another and coincide with two perimeter walls of the tray 7 (as in Figures 13-17) or be arranged one in correspondence with a side of the tray 7 (in other words be a perimeter wall) with the other in an intermediate position.

In the case where the first 40 wall and the second 41 wall are two perimeter walls of the tray 7 and the cells are arranged in two rows, the tray 7 may have a third wall substantially perpendicular to the base wall 9 and arranged between the two rows (this embodiment is also not shown in the figures). The third wall may optionally be provided with at least one further plate 13 equipped with electrical measuring contacts 14 if the electrochemical cells 2 housed in the respective seats 10 have the terminals 4 on two opposite sides of the cell.

The number of walls perpendicular to the base wall 9 and provided with the plate 13 equipped with electrical measuring contacts 14, and their arrangement, depend on the shape and type of electrochemical cells 2 in question, on the position of their terminals (both on the same side of the cell or on opposite sides of the cell) and/or on the number of rows of seats 10 housing the electrochemical cells 2 inside the tray 7.

As stated above, since the tray 7 may be without a top wall 12 or 43 or a cover, the tray 7 may likewise be without sides closed off by walls (for instance the first 40 and/or unique wall equipped with a plate 13 may be the one arranged between the two rows of seats 10). In correspondence with the sides of the tray 7 without a wall equipped with a plate 13 it is possible to provide, as an alternative to walls (with no plate 13), a retaining element even if small, for example a perimeter barrier, which helps to keep the cells in position during movements of the tray 7 or during the phases of processing.

Alternatively it is also possible not to have any perimeter retaining element in that the seats 10 made in the base wall 9 already ensure stable positioning of the electrochemical cells 2 including during the phases of movement of the tray 7.

Conversely to what has been described above and illustrated in the figures, the tray 7 according to the present invention may comprise seats 10 arranged in a single row, especially in the case of electrochemical cells 2 of large size.

The possibility of arranging the electrochemical cells 2 within the tray 7 as shown in Figures 13- 17 (in other words with the terminals arranged on the side instead of arranged facing the top) and the possibility of having configurations of the tray 7 other than those described with reference to said figures afford significant advantages.

The tray 7 in fact has an extremely flexible structure which may be easily adapted to the type of electrochemical cells 2 it is to contain, as well as to their shape, size and the arrangement of the terminals, without the need to redesign the entire tray 7, something which entails considerable costs and time.

Furthermore, the arrangement of the cells according to the embodiment of Figures 13-17, in other words with the terminals on the side instead of arranged facing the top, makes it possible to considerably reduce the space taken up by the tray 7 in terms of height, rendering it more stable.