Method for finishing at least partially electrochemical cells and cell tray for at least partial finishing process of electrochemical cells

Abstract

A method for at least partially finishing electrochemical cells (300) comprises providing a cell tray (10) comprising a plurality of housing arrays (14) wherein each housing array (14) comprises a plurality of housing seats (15) each configured to contain a respective electrochemical cell (300), a plurality of fluid passage cavities (19) wherein each fluid passage cavity (19) is defined between two adjacent housing arrays (14), a fluid delivery manifold (27) and a fluid return manifold (28), wherein the fluid delivery manifold (27) comprises a delivery connector (29) and is placed in fluid connection with the plurality of fluid passage cavities (19) and wherein the fluid return manifold (28) comprises a return connector (30) and is placed in fluid connection with the plurality of fluid passage cavities (19). The method comprises inserting an electrochemical cell (300) into each housing seat (15), inserting the cell tray (10) into a finishing station (201 ), hydraulically connecting the delivery connector (29) to delivery conduits (206) of a hydraulic circuit (202) and hydraulically connecting the return connector (30) to return conduits (207) of the hydraulic circuit (202), letting fluid flow from the delivery conduits (206) to the return conduits (207) of the hydraulic circuit (202) through the plurality of fluid passage cavities (19), implementing an at least partial finishing process of the electrochemical cells (300) contained in said cell tray (10).

Description

[0001] Method for finishing at least partially electrochemical cells and cell tray for at least partial finishing process of electrochemical cells DESCRIPTION

[0002] The present invention relates to a method for at least partially finishing electrochemical cells and a cell tray for the at least partial finishing process of electrochemical cells.

[0003] The present invention finds particular application in the production of secondary batteries, preferably rechargeable lithium batteries. Although in the course of this description, reference will be made specifically to lithium electrochemical cells, the teachings of the present invention also apply to the case of other secondary electrochemical cells.

[0004] In the production of lithium electrochemical cells, after mechanical assembly operations of the electrochemical cells, the electrochemical cells must be subjected to finishing operations (otherwise known as conditioning) to make them electrically active and stable.

[0005] A first of these finishing operations involves subjecting the electrochemical cells to electrical processes that determine electrochemical phenomena internal to the electrochemical cells such that the anodes are covered by the so-called "Solid Electrolyte Interphase" (SEI). This process is known in the technical field by the term of "formation" of electrochemical cells.

[0006] The electrochemical cell formation processes typically involve a succession of charging / discharging cycles of the electrochemical cells by applying currents of 0.1 -0.2 C for predetermined times (on the order of 10-24 hours). The magnitude "C" indicates a current value expressed in amperes numerically equal to the cell capacity in Ah (e.g. for a cell capacity of 2 Ah, the magnitude C is 2 A). The currents actually applied, the charging / discharging times and the number of repetitions of the various charging / discharging cycles depend on the type of battery and each battery manufacturer has developed its own "recipe" that allows to best form the electrode surface layer SEI to maximise battery performance. In fact, only if the formation process is performed properly will the electrode surface layer SEI be deposited on the electrodes of the battery, which optimizes the properties of the battery in terms of charging capacity and uniformity of charging / discharging cycles.

[0007] Subsequently to the formation process, the finishing operations continue by subjecting the formed electrochemical cells to electrically passive aging processes, carried out in special resting stations (aging stations) for times of the order of tens or hundreds of hours, in which the cells are allowed to "rest" to allow them to stabilize.

[0008] In the Applicant's experience, the finishing operations of the electrochemical cells are performed in a finishing plant in which cell trays, each containing a plurality of electrochemical cells arranged in a matrix pattern, are positioned in respective finishing chambers.

[0009] In the Applicant's experience, during the finishing process, and particularly during the aging process, electrochemical cells need to remain at controlled, predefined temperatures that are imposed by the particular finishing “recipe”.

[0010] In the Applicant's experience, finishing plants provide environments whose temperature is controlled and in which cell trays containing the electronic cells to be subjected to the finishing process are placed. When electrochemical cells need to be kept at a different temperature during the finishing process, it is provided that the cell trays containing these electrochemical cells are transferred to different environments that are kept at this different temperature.

[0011] The Applicant noted that the logistics of transporting cell trays between different environments of the finishing plant can be very complicated. The Applicant has in fact verified that the transfer of cell trays must be carefully planned, as it must be ensured, for example, that the cell trays to be transferred can actually find free stations in the environment to which they are to be transferred.

[0012] The Applicant also noted that the transfer of cell trays between different environments could expose the electrochemical cells to undesirable or otherwise sub-optimal temperatures, albeit only for the time required for the transfer.

[0013] The Applicant thus felt the need to simplify the logistics of transporting electrochemical cells within the finishing plant.

[0014] The Applicant envisaged arranging the environments in which the cell trays are placed in such a way that the temperature can be varied over time, so that the electrochemical cells can remain at predetermined temperatures without the need to move the cell trays between different environments of the finishing plant.

[0015] The Applicant verified that in this way all the cell trays contained in the same environment, and with them the electrochemical cells contained therein, would be exposed to different temperatures at the same time.

[0016] The Applicant noted, however, that this would require the electrochemical cells contained in the cell trays placed in the same environment to start and finish the finishing process at the same time, which would at the very least require careful management of the timing of the insertion of the cell trays into the various environments.

[0017] The Applicant perceived that if the volume of each environment were reduced so that each environment contained only one cell tray, it would be possible to set the temperature of that environment and vary that temperature substantially at will without affecting the finishing process of electrochemical cells contained in other environments.

[0018] The Applicant also perceived that in this way the number of environments configured to accommodate a single cell tray in a finishing plant would be extremely high and would entail too high an implementation cost to be economically viable.

[0019] The Applicant therefore found that the cell tray could be used as an environment configured for placing the electrochemical cells contained therein at the desired temperature. In this way, cell tray handling logistics would be simplified as there would be no need to move the cell trays to temperature-controlled environments, and implementation costs would be low as there would be no need to thermally condition the individual environments in which the cell trays are placed during electrochemical cell finishing operations.

[0020] The present invention therefore concerns, in a first aspect thereof, a method for at least partially finishing electrochemical cells.

[0021] Preferably, the method comprises providing a cell tray.

[0022] Preferably, the cell tray comprises a plurality of housing arrays wherein each housing array of said plurality of housing arrays comprises a plurality of housing seats, wherein each housing seat is configured to contain a respective electrochemical cell.

[0023] Preferably, the cell tray comprises a plurality of fluid passage cavities in which each fluid passage cavity of said plurality of fluid passage cavities is defined between two adjacent housing arrays.

[0024] Preferably, the cell tray comprises a fluid delivery manifold and a fluid return manifold.

[0025] Preferably, said fluid delivery manifold comprises a delivery connector and is placed in fluid connection with said plurality of fluid passage cavities.

[0026] Preferably, said fluid return manifold comprises a return connector and is placed in fluid connection with said plurality of fluid passage cavities.

[0027] Preferably, the method comprises inserting an electrochemical cell into each housing seat of the cell tray.

[0028] Preferably, the method comprises inserting said cell tray into a finishing station of a finishing plant.

[0029] Preferably, the method comprises hydraulically connecting said delivery connector to delivery conduits of a hydraulic circuit of the finishing plant.

[0030] Preferably, the method comprises hydraulically connecting said return connector to return conduits of said hydraulic circuit of the finishing plant.

[0031] Preferably, the method comprises letting fluid flow from the delivery conduits to the return conduits of the hydraulic circuit through said plurality of fluid passage cavities.

[0032] Preferably, the method comprises implementing at least a partial finishing process of the electrochemical cells contained in said cell tray.

[0033] The Applicant has verified that in this way the fluid flowing in the fluid passage cavities thermally conditions the electrochemical cells contained in the housing seats. Fluid flows into the fluid passage cavities through the hydraulic connections between the cell tray delivery connector and the delivery lines of the hydraulic circuit of the finishing plant, and flows out of the fluid passage cavities through the return connector of the cell tray and the return conduits of the hydraulic circuit of the finishing plant, allowing forced circulation of fluid within the fluid passage cavities when the cell tray is placed in a finishing station of the finishing plant. Each cell tray therefore does not necessarily have to be placed in a temperature-controlled environment to thermally condition the electrochemical cells contained in the cell tray. The present invention relates, in a second aspect thereof, to a cell tray for at least partial finishing processes of electrochemical cells.

[0034] Preferably, the cell tray comprises a plurality of housing arrays wherein each housing array of said plurality of housing arrays comprises a plurality of housing seats, wherein each housing seat is configured to contain a respective electrochemical cell.

[0035] Preferably, the cell tray comprises a plurality of fluid passage cavities in which each fluid passage cavity of said plurality of fluid passage cavities is defined between two adjacent housing arrays.

[0036] Preferably, the cell tray comprises a fluid delivery manifold and a fluid return manifold.

[0037] Preferably, said fluid delivery manifold comprises a delivery connector and is placed in fluid connection with said plurality of fluid passage cavities.

[0038] Preferably, said fluid return manifold comprises a return connector and is placed in fluid connection with said plurality of fluid passage cavities.

[0039] An “electrochemical cell” is defined as an assembly consisting of at least one anode, one cathode, a possible dielectric material separator interposed between the anode and cathode, and an electrolyte. A battery comprises at least one electrochemical cell.

[0040] “Finishing” of an electrochemical cell means a process of formation of the electrochemical cell followed by a process of aging of an electrochemical cell. “Partial finishing” of an electrochemical cell means an at least partial process of formation of the electrochemical cell or an at least partial process of aging of an electrochemical cell.

[0041] "Formation” means a process in which an electrochemical cell is subjected to charging / discharging / recharging cycles. The currents applied during charging / discharging / recharging cycles, measured in Amperes, are numerically of a lower order of magnitude than the number expressing the total capacity in Ah of the electrochemical cell. For example, when an electrochemical cell has a capacity of 1Ah, the maximum currents applied are about 0.1 - 0.2 amperes. The charging / discharging / recharging cycles are implemented for such a time (e.g. 12- 24 hours) to reach maximum voltage, minimum voltage, and then return the electrochemical cell to a known state of charge, typically 80%.

[0042] "Aging" refers to a maturing or consolidation process following an electrochemical cell formation process. In an aging process, electrochemical cells which have already undergone a formation process are kept at relatively high temperatures in order to make the electrochemical cell voltage more stable and precise. The aging process favours the consolidation and reorganisation of the SEI electrode surface layer formed during the formation process. An aging process can last for a period of 8-12 days.

[0043] To "thermally condition" a physical entity (such as a tray, an electrochemical cell, a liquid) is to subject that physical entity to a thermal heating or cooling action.

[0044] The present invention may have at least one of the preferred features described below. Such characteristics may be present individually or in combination with each other, unless expressly stated otherwise, both in the cell tray and in the method of the present invention.

[0045] Preferably, the cell tray is not configured for use in an EV vehicle battery pack.

[0046] Preferably, the cell tray is not suitable for making a battery pack that can be installed and used in an electric or hybrid vehicle.

[0047] Preferably, letting fluid flow through said plurality of fluid passage cavities is implemented while implementing an at least partial finishing process of the electrochemical cells contained in said cell tray.

[0048] Preferably, letting fluid flow through said plurality of fluid passage cavities is preceded by placing said fluid at least at a predetermined first temperature and sending said fluid at said predetermined first temperature to said delivery manifold.

[0049] Preferably, said first temperature is either a temperature provided by a formation process “recipe” or a temperature provided by an aging process “recipe”.

[0050] Preferably, the finishing plant can comprise a fluid conditioner connected to the hydraulic circuit of the finishing plant.

[0051] In this way, the fluid conditioner can cool and / or heat the fluid in such a way that the fluid reaching the cell tray through the delivery conduits of the hydraulic circuit of the finishing plant is at a predetermined temperature, e.g. said first temperature.

[0052] Preferably, said first temperature is a temperature below an ambient temperature in which the cell tray is placed.

[0053] Preferably, said first temperature is a temperature above an ambient temperature in which the cell tray is placed.

[0054] Preferably, letting fluid flow through said plurality of fluid passage cavities preceded by placing said fluid at least at a predetermined first temperature comprises letting fluid flow at said first temperature through said plurality of fluid passage cavities for a first period of time and discontinuing fluid passage through said plurality of fluid passage cavities for a second period of time.

[0055] In this way, it is possible to implement finishing recipes that require periods in which the electrochemical cells are maintained at the temperature of the environment in which the cell tray is placed.

[0056] Preferably, placing said fluid at least at a predetermined first temperature is followed by placing said fluid at a predetermined second temperature greater than said first temperature.

[0057] In this way, it is possible to implement finishing recipes that require electrochemical cells to be placed at different, predetermined temperatures.

[0058] Preferably, letting fluid flow through said plurality of fluid passage cavities preceded by placing said fluid at least at a predetermined first temperature comprises letting fluid flow at said first temperature through said plurality of fluid passage cavities for a first period of time, discontinuing fluid passage through said plurality of fluid passage cavities for a second period of time, and letting fluid flow at said second temperature through said plurality of fluid passage cavities for a third period of time.

[0059] Alternatively, letting fluid flow through said plurality of fluid passage cavities preceded by placing said fluid at least at a predetermined first temperature comprises letting fluid flow at said first temperature through said plurality of fluid passage cavities for a first period of time and letting fluid flow at said second temperature through said plurality of fluid passage cavities for a second period of time.

[0060] Preferably, during the at least partial finishing process of the electrochemical cells, it is provided to let fluid flow at said first temperature through said plurality of fluid passage cavities, optionally preceded or followed by interrupting the passage of fluid at said first temperature through said plurality of fluid passage cavities, optionally followed by letting fluid flow at said second temperature through said plurality of fluid passage cavities, optionally preceded or followed by discontinuing fluid passage at said second temperature through said plurality of fluid passage cavities until the at least partial finishing process of the electrochemical cells is terminated.

[0061] Preferably, it is provided to remove said cell tray from said finishing station at the end of the at least partial finishing process of the electrochemical cells.

[0062] Preferably, removing said cell tray from said finishing station comprises hydraulically disconnecting said delivery connector of the cell tray from said delivery conduits of the hydraulic circuit of the finishing plant and hydraulically disconnecting said return connector of the cell tray from the return conduits of said hydraulic circuit of the finishing plant.

[0063] In this regard, the delivery connector of the cell tray is a preferably quick-coupling connector.

[0064] A quick-coupling connector is a hydraulic connector of the type that can be connected to and disconnected from a further hydraulic connector without the need for clamping tools.

[0065] In this way, connection and disconnection operations between the delivery connector of the cell tray and the delivery conduits of the hydraulic circuit of the finishing plant can be made easier and faster.

[0066] Preferably, the return connector of the cell tray is a quick-coupling connector.

[0067] In this way, the connection and disconnection operations between the return connector of the cell tray and the return conduits of the hydraulic circuit of the finishing plant can also be made easier and faster.

[0068] Preferably, the tray comprises a frame comprising a plurality of side walls and a top wall.

[0069] Preferably, each housing seat comprises a top opening configured for the insertion and removal of an electrochemical cell. Preferably, each housing seat comprises a through base opening opposite the top opening.

[0070] Preferably, each housing seat is delimited by a base abutment wall configured to receive restingly an electrochemical cell.

[0071] Preferably, the base abutment wall is opposite the top opening.

[0072] Preferably, the base abutment wall is placed at the bottom through-opening of a respective housing seat to expose a base of the electrochemical cell to the environment external to the cell tray.

[0073] In this way, each electrochemical cell can be electrically contacted at its base by an electrical contacting unit of a formation device in order to implement at least a partial formation cycle.

[0074] Preferably, each housing seat is separated from an adjacent housing seat of a same housing array by a partition septum.

[0075] The partition septum has the dual function of physically separating two adjacent electrochemical cells from each other and electrically isolating two adjacent electrochemical cells from each other.

[0076] Preferably, each housing array comprises a first side wall and a second side wall.

[0077] Preferably, each fluid passage cavity is defined between said first side wall of a housing array and said second side wall of an adjacent housing array.

[0078] In other words, each fluid passage cavity is implemented by an empty space between the first side wall of a housing array and the second side wall of an adjacent housing array.

[0079] Preferably, each housing seat of a housing array is delimited by portions of said first side wall and said second side wall.

[0080] The Applicant perceived that the cell tray can also be used to prevent an immediate propagation of a thermal runaway event from an electrochemical cell to electrochemical cells in the same cell tray or cell trays in close proximity.

[0081] A thermal runaway is a chain reaction within an electrochemical cell that can be very difficult to stop once started. A thermal runaway occurs when the temperature inside an electrochemical cell is such that it causes a chemical reaction within the electrochemical cell. This chemical reaction produces even more heat, which raises the temperature, causing further chemical reactions that create more heat. A thermal runaway can, for example, occur due to an internal short circuit in the electrochemical cell.

[0082] In this regard, it is preferable to flood at least one housing seat with said fluid in the event that a wall of said at least one housing seat reaches a temperature above a predetermined temperature.

[0083] This predetermined temperature is preferably comprised between 100 °C and 250 °C, more preferably comprised between 120 °C and 200 °C, more preferably between 130 °C and 180 °C, e.g. around 165 °C.

[0084] The Applicant has verified that when the temperature of the first or second side wall of a housing array reaches or exceeds that temperature at a housing seat, it is very likely if not certain that the electrochemical cell contained in that housing seat is in thermal runaway state.

[0085] By flooding this housing seat with said fluid, the temperature of the electrochemical cell can be decreased, not further increased, or increased with less progression, so as to decrease the risk of thermal runaway propagating to adjacent electrochemical cells, triggering a chain thermal runaway process.

[0086] The Applicant also found that in order to flood a housing with said fluid, each housing array can be used as a “thermal fuse” in the event of a thermal runaway of an electrochemical cell.

[0087] In this regard, preferably flooding at least one housing array with said fluid comprises preparing said plurality of housing arrays with a material configured to melt at a temperature comprised between 100 °C and 250 °C, more preferably comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

[0088] More preferably, the Applicant has found that the first side wall and the second side wall of each housing array can be used as a “thermal fuse” in the event of a thermal runaway of an electrochemical cell.

[0089] Preferably, the first and second walls of each housing array are made of a material with a melting temperature comprised between 120 °C and 200 °C, more preferably between 130 °C and 180 °C, for example of about 165 °C. Thus, when the temperature of the first side wall or the second side wall of a housing array reaches the melting temperature at a housing seat, the first side wall or the second side wall melts at the housing seat, allowing the fluid flowing through the fluid passage cavity to flood the housing seat.

[0090] Preferably, the partition septa of a housing array extend between, and are connected to, the first side wall and the second side wall of the housing array.

[0091] Preferably, said partition septa, said first side wall and said second side wall of a housing array are integral with each other.

[0092] Preferably, said partition septa, said first side wall and said second side wall of a housing array are made of the same material.

[0093] Preferably, all the housing arrays are integral with each other.

[0094] Preferably, all the housing arrays are integral with each other and made of the same material.

[0095] Preferably, the housing seats of a housing array are offset in a longitudinal direction to the housing seats of an adjacent housing array.

[0096] In this way, it is possible to implement a matrix arrangement of the housing sets of the entire cell tray that minimises the distance separating one housing seat from the adjacent housing seats, thus minimising the size of the cell tray.

[0097] Preferably, each housing seat is generically cylindrical in shape to accommodate electrochemical cells of essentially cylindrical shape.

[0098] In an embodiment, each housing seat is flared as it converges towards the bottom through-opening.

[0099] Preferably, the fluid passage cavity between two adjacent housing arrays has a serpentine shape, along said longitudinal direction, between the housing seats of said two housing arrays.

[0100] In this way, it is possible to increase the surface area of each housing seat lapped by the fluid passage cavities, maximising the heat exchange between the fluid and the electrochemical cells contained in the housing seats.

[0101] Preferably, the first and second walls of each housing array develop in the longitudinal direction with a serpentine shape. Preferably, each fluid passage cavity has a substantially constant passage crosssection.

[0102] In a first embodiment, preferably, the first side wall of a housing array is parallel to the second side wall of an adjacent housing array.

[0103] In this first embodiment, preferably, each first side wall of each housing array comprises a first edge and a second edge projecting in the direction of the second wall of an adjacent housing array.

[0104] In this first embodiment, preferably, said first edge of each first side wall at least partially defines a top wall of a respective fluid passage cavity and said second edge of each first side wall at least partially defines a base wall of a respective fluid passage cavity.

[0105] In this first embodiment, preferably, each second wall of each housing array comprises a third edge and a fourth edge projecting in the direction of the first side wall of an adjacent housing array.

[0106] In this first embodiment, preferably, said third edge of a second wall defines, in combination with said first edge of the first side wall of an adjacent housing array, said top wall of the respective fluid passage cavity.

[0107] In this first embodiment, preferably, said fourth edge of a second wall defines, in combination with said second edge of the first side wall of an adjacent housing array, said base wall of the respective fluid passage cavity.

[0108] In this way, each fluid passage cavity is preferably delimited by the first side wall, first edge and second edge of the first side wall of a housing array and the second wall, third edge and fourth edge of the second wall of an adjacent housing array.

[0109] In a second embodiment, preferably each fluid passage cavity is delimited by the top wall of the tray frame.

[0110] In this second embodiment, preferably each fluid passage cavity is tapered in the direction of the top wall of the tray frame.

[0111] In this second embodiment, preferably, the tray comprises a bottom lid placed on the opposite side with respect to the top wall of the frame. Preferably, each fluid passage cavity is also delimited by the bottom lid. Preferably. The bottom lid comprises a plurality of lid openings located at the bottom through-openings of the housing seats.

[0112] Preferably, each lid opening is counter-shaped to the respective bottom through- opening.

[0113] Preferably, the bottom lid is not made as a single piece with the frame.

[0114] Preferably, the bottom lid is made of the same material as the frame.

[0115] Preferably, the bottom lid is made integral with the frame by hot plate welding.

[0116] Preferably, the tray comprises a vent valve.

[0117] Preferably, said fluid delivery manifold is placed at a first end of said plurality of housing arrays and said fluid return manifold is placed at a second end, opposite said first end, of said plurality of housing arrays.

[0118] Preferably, said first side wall and said second side wall of each housing array are developed between said fluid delivery manifold and said fluid return manifold.

[0119] In this way, the fluid flowing in the fluid passage cavities follows a path from a first end of the cell tray to a second end, longitudinally opposite the first end, of the cell tray.

[0120] Preferably, said fluid delivery manifold comprises a plurality of passage openings each directly facing a respective fluid passage cavity.

[0121] In this way, each fluid passage cavity is directly hydraulically connected to the delivery manifold via a dedicated passage opening in the delivery manifold.

[0122] Preferably, said fluid return manifold comprises a plurality of passage openings each directly facing a respective fluid passage cavity.

[0123] In this way, each fluid passage cavity is directly hydraulically connected to the return manifold via a dedicated passage opening in the return manifold.

[0124] Preferably, a first distance measured between said base abutment wall and said top opening of each housing seat is greater than 90 % of an electrochemical cell height.

[0125] In this way, each housing seat essentially surrounds an entire electrochemical cell.

[0126] Preferably, a height of said fluid passage cavity is greater than 80% of said first distance.

[0127] In this way, each fluid passage cavity essentially laps an entire housing seat in height.

[0128] Further characteristics and advantages of the present invention will become clearer from the following detailed description of some preferred embodiments, with reference to the appended drawings and provided by way of indicative and non-limiting example, in which:

[0129] Figures 1 and 2 are perspective views of a first embodiment of a cell tray for at least partial finishing process of electrochemical cells in accordance with the present invention;

[0130] Figure 3 is a sectional view according to plane Ill-Ill of the cell tray in Figure 1 ;

[0131] Figures 4 to 6 are perspective views of some components of the cell tray in Figure 1 ;

[0132] Figure 7 is a sectional view according to plane VII-VII of the cell tray component in Figure 5;

[0133] Figure 8 is a schematic representation of an electrochemical cell finishing plant using the cell tray in Figure 1 ;

[0134] Figures 9 and 10 are perspective views of a second embodiment of a cell tray for at least partial finishing process of electrochemical cells in accordance with the present invention;

[0135] Figure 11 is a sectional view according to plane XI-XI of the cell tray in Figure 9;

[0136] Figure 12 is a sectional view according to plane XII-XII of the cell tray in Figure 9; and

[0137] Figure 13 is a perspective view of a component of the tray in Figure 9.

[0138] The representations in the accompanying figures are not to be understood in scale, do not necessarily respect the proportions between the various parts and are to be understood as diagrams.

[0139] With reference to Figure 1 , a cell tray for at least partial finishing processes of electrochemical cells in accordance with a first embodiment of the present invention has been referred to as 10.

[0140] The cell tray 10 comprises a frame 11 that defines a footprint for the tray 10. The frame 11 comprises four side walls 12 and a back wall 13 (shown in Figure 2).

[0141] The cell tray 10 comprises a plurality of housing arrays 14 each comprising a plurality of housing arrays 15 for electrochemical cells 300. Each housing seat 15 is configured to receive only one electrochemical cell 300. The plurality of housing arrays 14 is contained within the frame 11 . Each housing array 14 is arranged to rest on the back wall 13 of the frame 11 .

[0142] Each housing seat 15 is generically cylindrically shaped to contain a cylindrical shaped electrochemical cell. Each housing seat 15 is substantially formed by a cylindrical through-hole. Each housing seat 15 comprises a top opening 16 configured for inserting and extracting an electrochemical cell 300 from the housing seat 15. On the opposite side of the top opening 16, each housing seat 15 comprises a bottom through-opening 17 (Figure 7) substantially identical to the top opening 16. Each housing seat 15 is delimited by a base abutment wall 18. The base abutment wall 18 is defined on the back wall 13 of the frame 11 of the cell tray 10, as schematically depicted in Figure 2. The bottom through- opening 17 of each housing seat 15 is directly facing the base abutment wall 18 and is partially closed by the base abutment wall 18. The base abutment wall 18 comprises a through-opening 19 that is smaller than the bottom through-opening 17 of the housing seat 15, such that an electrochemical cell 300 inserted into the housing seat 15 rests against and is supported by the base abutment wall 18 while still remaining directly accessible from outside the cell tray 10. As schematically illustrated in Figure 3, each electrochemical cell 300 inserted into a housing seat 15 is exposed to the environment outside the cell tray 10 at both its upper and lower ends, such that it can be contacted by contacting assemblies during at least a partial finishing process. As illustrated in Figures 1 and 3, the cell tray 10 is not closed at the top, i.e. it does not comprise a closing lid. The cell tray 10 does not house the electrochemical cells in a sealed manner with respect to the external environment. As shown in Figure 1 , the housing arrays 14 are arranged inside the cell tray 10 next to each other. A fluid passage cavity 19 (Figure 3) configured to receive and let a fluid, preferably a liquid, flow is defined between two adjacent housing arrays 14. Each fluid passage cavity 19 is closed fluid-tight with respect to the environment outside the cell tray 10.

[0143] In this regard, each housing array 14 comprises a first side wall 20 (Figure 5) and a second side wall 21 (Figure 6) opposite the first side wall 20. The first side wall 20 and the second side wall 21 extend along the entire longitudinal development of the housing array 14. The first side wall 20 and the second side wall 21 are solid walls, i.e. they are continuous walls and have no holes or openings. The first side wall 20 of a housing array 14 directly faces the second side wall 21 of an adjacent housing array 14. The first side wall 20 of a housing array 14 and the second side wall 21 of an adjacent housing array 14 laterally delimit a respective fluid passage cavity 19.

[0144] The first side wall 20 comprises a first edge 22 and a second edge 23 that project in a substantially perpendicular direction from the first side wall 20. The first edge 22 and the second edge 23 are opposite each other. The first edge 22 is placed at the top openings 16 of the housing seat 15 of the housing array 14, as shown in Figure 5. The second edge 23 is placed at the bottom through-holes 17 of the housing seats 15 of the housing array 14.

[0145] The second side wall 21 comprises a third edge 24 and a fourth edge 25 projecting in a substantially perpendicular direction from the second side wall 21. The third edge 24 and the fourth edge 24 are opposite each other. The third edge 24 is placed at the top openings 16 of the housing seat 15 of the housing array 14, as shown in Figure 6. The fourth edge 25 is placed at the bottom through- openings 17 of the housing seats 15 of the housing array 14.

[0146] The first edge 22 of the first side wall 20 of a housing array 14 is in contact with the third edge 24 of the second wall 21 of an adjacent housing array 14. The first edge 22 of the first side wall 20 of a housing array 14 is in fluid-tight contact with the third edge 24 of the second wall 21 of an adjacent housing array 14. The second edge 23 of the first side wall 20 of a housing array 14 is in contact with the fourth edge 25 of the second wall 21 of an adjacent housing array 14. The second edge 23 of the first side wall 20 of a housing array 14 is in fluid-tight contact with the fourth edge 25 of the second wall 21 of an adjacent housing array 14. The first edge 22 of the first side wall 20 of a housing array 14 and the third edge 24 of the second side wall 21 of an adjacent housing array 14 superiorly delimit a respective fluid passage cavity 19. The second edge 23 of the first side wall 20 of a housing array 14 and the fourth edge 25 of the second wall 21 of an adjacent housing array 14 inferiorly delimit a respective fluid passage cavity 19.

[0147] As, for example, illustrated in Figures 5 and 6, the first side wall 20 and the second side wall 21 of a housing array 14 define portions of the housing seats 15. The housing seats 15 of the same housing array 14 are separated from each other by partition septa 26 that connect to the first side wall 20 and the second side wall 21.

[0148] The partition septa 26, the first side wall 20 and the second side wall 21 of the same housing array 14 are integral with each other and are made of the same material. The material of which each housing array 14 is made is a polymer material and does not comprise any metallic material. Each housing array 14 and, in particular, the first side wall 20 and the second side wall 21 are made of a material with a melting point comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

[0149] The first side wall 20 and the second side wall 21 have a serpentine shape created by successive curved portions. Two successive curved portions have opposite concavities. The housing seats 15 of adjacent housing arrays 14 are offset from each other in the longitudinal direction, as illustrated in Figure 1 , so as to maximise the ratio of the number of housing seats 15 to the area of the cell tray 10. Note that the first side wall 20 and the second side wall 21 of the same housing array 14 are not parallel. The first side wall 20 and the second side wall 21 of two adjacent housing 14 arrays are parallel to each other.

[0150] The height of each housing seat 15 is essentially equal to the height of an electrochemical cell 300. In particular (see Figure 3), a first distance D1 measured between the base abutment wall 18 and the top opening 16 of each housing seat 15 is greater than 90% of the height of an electrochemical cell 300. Preferably, the first distance D1 is equal to the height of an electrochemical cell 300. The height of the fluid passage cavity 19 is slightly less than the height of an electrochemical cell 300. In particular, a height D2 of the fluid passage cavity 19 is greater than 80% of the first distance D1 , preferably equal to about 95% of the first distance D1 , as depicted in Figure 3. The height D2 of a fluid passage cavity 19 is constant along the entire longitudinal development of the fluid cavity 19. The height D2 of a fluid passage cavity 19 is measured as the minimum distance between the first edge 22 and the second edge 23 of the first side wall 20.

[0151] The cell tray 10 also comprises a fluid delivery manifold 27 and a fluid return manifold 28. The fluid delivery manifold 27 receives fluid from a finishing plant 200 and sends it into the fluid passage cavities 19. The fluid return manifold 28 receives fluid from the fluid passage cavities 19 and sends it to the finishing plant 200.

[0152] As illustrated in Figure 1 , the fluid delivery manifold 27 is placed at a first end 10a of the cell tray 10 and the fluid return manifold 28 is placed at a second end 10b of the cell tray 10 opposite the first end 10a. The fluid delivery manifold 27 comprises a fluid delivery connector 29 and is placed in fluid connection with the plurality of fluid passage cavities 19. The fluid return manifold 28 comprises a return connector 30 and is placed in fluid connection with the plurality of fluid passage cavities 19.

[0153] The delivery connector 29 and the return connector 30 are preferably quickcoupling electrical connectors, i.e. hydraulic connectors that can be connected to further hydraulic connectors and disconnected from said further hydraulic connectors without the need to use clamping tools. These hydraulic connectors are also of the “zero-drop” type, i.e. they do not allow the passage of fluid when not connected to additional hydraulic connectors. When the delivery connector 29 and return connector 30 are not connected to further hydraulic connectors, the delivery connector 29 and return connector 30 close a hydraulic circuit, i.e. they do not allow fluid to pass through.

[0154] As illustrated in Figure 1 , the fluid delivery manifold 27 is a box-shaped body that develops transversely along the entire cell tray 10 and is contained in the frame 11 of the cell tray 10. The fluid delivery manifold 27 comprises a plurality of fluid passage openings 31 , in particular at least one fluid passage opening 31 for each fluid passage cavity 19 (Figure 4). Similarly, the fluid return manifold 28 is a boxshaped body that runs transversely along the entire cell tray 10 and is contained in the frame 11 of the cell tray 10. The fluid return manifold 28 comprises a plurality of passage openings 32 (only some of which are illustrated in a dotted line in Figure 4), in particular at least one fluid passage opening 32 for each fluid passage cavity 19. Each fluid passage cavity 19 comprises respective fluid passage openings 33 directly facing and fluid-tightly associated with passage openings 30 of the fluid delivery manifold 27 and with passage openings 32 of the fluid return manifold 28. The passage openings 33 of each fluid passage cavity 19 are made at the ends of the first side wall 20 and the second side wall 21. The first side wall 20 of a housing array 14 comprises first half-openings 33a and the second side wall 21 comprises second half-openings 33b, as illustrated in Figure 5. The first half-openings 33a of a housing array 14 are fluid-tightly coupled with the second half-openings 33b of an adjacent housing array 14, creating the aforementioned passage openings 33.

[0155] With reference to Figure 9, a cell tray for at least partial finishing processes of electrochemical cells in accordance with a second embodiment of the present invention has been referred to as 100.

[0156] The cell tray 100 comprises a frame 101 that defines a footprint for the tray 100. The frame 101 comprises four side walls 12 and one top wall 103.

[0157] The cell tray 100 comprises a plurality of housing arrays 104 each of which comprises a plurality of housing seats 105 for electrochemical cells 300. Each housing seat 105 is configured to receive only one electrochemical cell 300. The plurality of housing arrays 104 is contained within the frame 101 .

[0158] Each housing seat 105 comprises a top opening 106 configured to insert and extract an electrochemical cell 300 from the housing seat 105. The top opening 106 is located at the top of the housing seat 105. On the opposite side of the top opening 106, each housing seat 105 comprises a bottom through-opening 107 (Figure 11 ). Each housing seat 105 is generically shaped like a truncated pyramid with a circular base passing through and is configured to contain an electrochemical cell 300. The base of said truncated pyramid is located at the bottom through-opening 107 of the housing seat 105 and the top of said truncated pyramid is located at the top opening 106 of the housing seat 105. The base of such a truncated pyramid is smaller in size than the top of the truncated pyramid, so that each housing seat is flared as it converges towards the bottom through- opening 107. The bottom through-opening 107 has dimensions, for example a diameter, smaller than the dimensions, for example a diameter, of the top through-opening 106. Each housing seat 105 is delimited by a base abutment wall 108. The base abutment wall 108 is defined by an at least partially annular protrusion 108a integral with the housing seat 105 which develops at the bottom through-opening 107. The base abutment wall 108 acts as an abutment and support for an electrochemical cell 300 inserted into the housing seat 105. However, the electrochemical cell 300 remains directly accessible from outside the cell tray 100 at the base abutment wall 108. Each electrochemical cell 300 inserted into a housing seat 105 is exposed to the environment outside the cell tray 100 at both its upper and lower ends, such that it can be contacted by contacting assemblies during at least a partial finishing process. The housing seats 105 of the cell tray 100 are not closed at the top. The cell tray 100 does not house the electrochemical cells in a sealed manner with respect to the external environment.

[0159] As shown in Figure 9, the housing arrays 104 are arranged inside the cell tray 100 next to each other. A fluid passage cavity 109 (Figure 12) configured to receive and let a fluid, preferably a liquid, flow is defined between two adjacent housing arrays 104. Each fluid passage cavity 109 is closed fluid-tight with respect to the environment outside the cell tray 11 .

[0160] In this regard, each housing array 104 comprises a first side wall 110 and a second side wall 111 opposite the first side wall 110. The first side wall 110 and the second side wall 111 extend along the entire longitudinal development of the housing array 104. The first side wall 110 and the second side wall 111 are solid walls, i.e. they are continuous walls and have no holes or openings. The first side wall 110 of a housing array 104 directly faces the second side wall 111 of an adjacent housing array 104. The first side wall 110 of a housing array 104 and the second side wall 111 of an adjacent housing array 104 laterally delimit a respective fluid passage cavity 109. The fluid passage cavity 109 is also delimited at the top by the top wall 103 of the frame 101 .

[0161] The first side wall 110 of a housing array 104 and the second side wall 111 of an adjacent housing array 104 are not parallel to each other. The first side wall 110 of a housing array 104 and the second side wall 111 of an adjacent housing array 104 are converging with each other in the direction of the top opening 106 of the housing seats 105, as illustrated in Figure 11 . The first side wall 110 of a housing array 104 and the second side wall 111 of an adjacent housing array 104 are converging with each other in the direction of the top opening 103 of the frame 101 , as illustrated in Figure 11 . The first side wall 110 of a housing array 104 and the second side wall 111 of an adjacent housing array 104 are divergent from each other in the direction of the bottom through-opening 107 of the housing seats 105.

[0162] The tray 100 also comprises a bottom lid 112, better illustrated in Figure 13, located on the opposite side with respect to the top wall 103. The fluid passage cavity 109 is also delimited at the bottom, i.e. on the opposite side with respect to the top wall, by the bottom lid 112. The bottom lid 112 comprises a plurality of lid openings 113 located at the bottom through-openings 107 of the housing seats 105. Each lid opening 113 is counter-balanced to the respective bottom through- opening 107, so as not to close the opening defined by the bottom through- opening 107.

[0163] As, for example, illustrated in Figure 12, the first side wall 110 and the second side wall 111 of a housing array 104 define portions of the housing seats 105. The housing seats 105 of the same housing array 104 are separated from each other by partition septa 114 that connect to the first side wall 110 and the second side wall 111.

[0164] The partition septa 114, the first side wall 110 and the second side wall 111 of the same housing array 104 are integral with each other and are made of the same material. The partition walls 114, the first side walls 110 and the second side walls 111 of all the housing arrays 104 are integral with each other, i.e. they are made from a single piece of the same polymer material. The frame 101 and the top wall 103 are made in one piece with the partition septa 114, the first side walls 110 and the second side walls 111 of all the housing arrays 104. The frame 101 , the top wall 103, the partition septa 114, the first side walls 110 and the second side walls 111 of all the housing arrays 104 are made by moulding. The bottom lid 112 is not made as a single piece with the frame 101 . The bottom lid 112 is made of the same material as the frame 101. The bottom lid 112 is made integral with the frame 101 by hot plate welding. Hot plate welding requires that the two parts to be welded, i.e. the frame 101 and the bottom lid 112, be positioned in a support seat connected to opposite sides of a press. A hot plate, having a shape that replicates the geometry of the two parts to be welded, is positioned between the two parts. The two opposite sides of the press bring the parts into contact with the hot plate until the heat softens the surfaces, reaching the melting point of the material of which the bottom lid 112 and frame 101 are made. When this condition is reached, the hot plate is removed, the parts are pressed together and the position is maintained until the weld spot cools and solidifies, creating a permanent joint.

[0165] The material of which each housing array 104 and frame 101 is made is a polymer material and does not comprise any metal material. Each housing array 104 and, in particular, the first side wall 110 and the second side wall 11 1 are made of a material with a melting point comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

[0166] The first side wall 110 and the second side wall 111 have a serpentine shape created by successive curved portions. Two successive curved portions have opposite concavities. The housing seats 105 of adjacent housing arrays 104 are offset from each other in the longitudinal direction, as illustrated in Figure 12, so as to maximise the ratio of the number of housing seats 105 to the area of the cell tray 100. Note that the first side wall 110 and the second side wall 111 of the same housing array 104 are not parallel.

[0167] The height of each housing seat 105 is essentially equal to the height of an electrochemical cell 300. In particular (see Figure 11 ), a first distance D1 measured between the base abutment wall 108 and the top opening 106 of each housing seat 105 is greater than 90% of the height of an electrochemical cell 300. Preferably, the first distance D1 is equal to the height of an electrochemical cell 300. The height of the fluid passage cavity 109 is slightly greater than or equal to the height of an electrochemical cell 300. In particular, a height D2 of the fluid passage cavity 109 is greater than or equal to the first distance D1 , as depicted in Figure 11. The height D2 of a fluid passage cavity 109 is constant along the entire longitudinal development of the fluid cavity 109. The height D2 of a fluid passage cavity 109 is measured as the minimum distance between the top wall 103 of the frame 101 and the bottom lid 112.

[0168] The cell tray 100 also comprises a fluid delivery manifold 115 and a fluid return manifold 116. The fluid delivery manifold 115 receives fluid from a finishing plant 200 and sends it into the fluid passage cavities 109. The fluid return manifold 116 receives fluid from the fluid passage cavities 109 and sends it to the finishing plant 200.

[0169] As illustrated in Figure 10, the fluid supply manifold 115 is located at a first end 117 of the cell tray 100 and the fluid return manifold 1 16 is located at a second end 118 of the cell tray 100 opposite the first end 117. The fluid delivery manifold 115 comprises a fluid delivery connector 119 and is placed in fluid connection with the plurality of fluid passage cavities 109. The fluid return manifold 116 comprises a return connector 120 and is placed in fluid connection with the plurality of fluid passage cavities 109.

[0170] The delivery connector 119 and the return connector 120 are preferably quickcoupling electrical connectors, i.e. hydraulic connectors that can be connected to further hydraulic connectors and disconnected from said further hydraulic connectors without the need to use clamping tools. These hydraulic connectors are also of the “zero-drop” type, i.e. they do not allow the passage of fluid when not connected to additional hydraulic connectors. When the delivery connector 119 and return connector 120 are not connected to further hydraulic connectors, the delivery connector 119 and return connector 120 close a hydraulic circuit, i.e. they do not allow fluid to pass through. The supply connector 119 and the return connector 120 are identical to each other so that they can be used indifferently for fluid inlet or outlet from the tray 100. As illustrated in Figure 12, the delivery connector 119 and the return connector 120 are positioned symmetrically with respect to a reference plane P perpendicular to the top wall 103 of the frame 101 and passing through a geometric centre of the tray 101. The supply connector 119 and the return connector 120 are completely positioned on opposite sides of this reference plane P.

[0171] As illustrated in Figure 12, the fluid delivery manifold 115 is a box-shaped body that develops transversely along the entire cell tray 100 and is contained in the frame 101 of the cell tray 100. The fluid delivery manifold 115 comprises a plurality of passage openings 121 , in particular at least one passage opening 121 for each fluid passage cavity 109. Similarly, the fluid return manifold 116 is a boxshaped body that runs transversely along the entire cell tray 100 and is contained in the frame 101 of the cell tray 100. The fluid return manifold 116 comprises a plurality of passage openings 122, in particular at least one passage opening 122 for each fluid passage cavity 109.

[0172] The fluid delivery manifold 115 is made as a single piece with the frame 101 . The fluid return manifold 116 is made as a single piece with the frame 101 . The frame 101 , the top wall 103, the partition septa 114, the first side walls 110, the second side walls 111 of all the housing arrays 104 are made as a single piece with the fluid delivery manifold 115. The frame 101 , the top wall 103, the partition septa 114, the first side walls 110, the second side walls 111 of all the housing arrays 104 are made as a single piece with the fluid return manifold 116. The fluid delivery manifold 115 is delimited by the frame 101 and the bottom lid 112. The fluid return manifold 116 is delimited by the frame 101 and the bottom lid 112. As illustrated in Figure 13, the bottom lid 112 comprises a first sleeve 123 into which the fluid delivery manifold 115 is inserted. The bottom lid 112 comprises a second sleeve 124 into which the fluid return manifold 116 is inserted. The first sleeve 123 and the second sleeve 124 are made as a single piece with the bottom lid 112.

[0173] As schematically illustrated in Figure 9, the side walls 102 of the frame 101 comprise a plurality of ribs 125. These ribs 125 have the function of reinforcing the side walls 102 in such a way as to better support high pressures of fluid flowing inside the frame 101 and in the fluid passage cavities 109. These ribs 109 take the form of buttresses or struts for the side walls 102 of the frame 101 . As illustrated in Figure 9, a plurality of projections 126 are provided on the top wall 103 of the frame 101 . Such projections 126 are provided at corner portions of the top wall 103. The bottom lid 112 comprises a plurality of recesses 127. Such recesses 127 are provided at corner portions of the bottom lid 112. The projections 126 of a tray 100 are configured to fit into recesses 127 of another tray 100 so that a plurality of trays 100 can be neatly and stably stacked together.

[0174] Cell trays of the described embodiments can include vent valves. These vent valves have the function of removing air that may accumulate inside the trays, e.g. following a series of connections and disconnections of the hydraulic manifolds. In the embodiment of Figure 9, a vent valve (not shown) can be positioned inside one of the protrusions 126, as they are located at the top of the tray 100.

[0175] A method of at least partial finishing electrochemical cells using the cell tray 10, 300 in accordance with the first embodiment or the second embodiment described above will now be described.

[0176] The method involves providing a finishing station 200 (depicted in Figure 8) with at least one finishing station 201 , preferably a plurality of finishing stations 201 .

[0177] The finishing stations 201 are preferably stations and / or positions occupied by the cell trays 10 during an at least partial finishing process of the electrochemical cells 300.

[0178] Inside each finishing station 201 electrical equipment and electronic devices (not shown) can be placed, configured to implement the at least partial finishing process.

[0179] For example, in the case where a finishing station 201 is a formation station, at least one contacting assembly configured to electrically couple to electrochemical cells 300 contained in a cell tray 10 is placed in the formation station. The contacting assembly is electrically connected to a respective formation module configured to supply electrical energy to the electrochemical cells and perform a formation "recipe".

[0180] For example, if a finishing station 201 is an aging station, cell trays 10 containing the electrochemical cells 300 to be aged are placed in the aging station.

[0181] The method for at least partial finishing electrochemical cells involves thermally conditioning the electrochemical cells 300 contained in the cell tray 10.

[0182] As depicted in Figure 8, the finishing plant 200 comprises a hydraulic circuit 202. A fluid circulates in the hydraulic circuit, preferably a liquid that is heated and / or cooled to act as a heating or cooling agent. This liquid may for example be demineralized, osmotized or distilled water. The finishing plant 200 comprises a fluid conditioner 203 connected to the hydraulic circuit 202 of the finishing plant 200. The fluid conditioner 203 may, for example, comprise a fluid heater 204 and a fluid cooler 205, as in the example shown in Figure 8. The fluid heater 204 and fluid cooler 205 may be any device capable of heating and cooling the liquid of the hydraulic circuit 202. The fluid heater 204 and the fluid cooler 205 may be a single device or physically separate devices.

[0183] The hydraulic circuit 202 has the function of bringing liquid to each finishing station 201. For this purpose, the hydraulic circuit 202 comprises delivery conduits 206 and return conduits 206. The delivery conduits 206 and return conduits 207 connect the fluid conditioner 203 to the finishing stations 210. The delivery conduits 206 comprise hot delivery conduits 206a connecting the fluid heater 204 with each finishing station 201 and carrying hot liquid from the fluid heater 204 to the finishing stations 201 . The return conduits 207 comprise hot return conduits 207a connecting the fluid heater 204 with each finishing station 201 and returning liquid from the finishing stations 201 to the fluid heater 204. The delivery lines 206 also comprise cold delivery conduits 206b connecting the fluid cooler 205 with each finishing station 201 and carrying cold liquid from the fluid cooler 205 to the finishing stations 201 . The return conduits 207 comprise cold return conduits 207b connecting the fluid cooler 205 with each finishing station 201 and returning liquid from the finishing stations 201 to the fluid cooler 205, as depicted in Figure 8.

[0184] The hydraulic circuit 202 further comprises delivery hydraulic connectors 208 and return hydraulic connectors 209 placed at each finishing station 201 to connect with the cell trays 10 present in the finishing stations 201 . The delivery hydraulic connectors 208 and return hydraulic connectors 209 are located on the delivery conduits 206 and return conduits 207 respectively. The delivery hydraulic connectors 208 and the return hydraulic connectors 208 are preferably quickcoupling electrical connectors, i.e. hydraulic connectors that can be connected to further hydraulic connectors and disconnected from said further hydraulic connectors without the need to use clamping tools. These hydraulic connectors are also of the “zero-drop” type, i.e. they do not allow the passage of fluid when not connected to additional hydraulic connectors. When the delivery hydraulic connectors 208 and return hydraulic connectors 209 are not connected to further hydraulic connectors, the delivery hydraulic connectors 208 and return hydraulic connectors 209 close the hydraulic circuit 202.

[0185] The method for at least partial finishing electrochemical cells comprises inserting electrochemical cells 300 into the housing seats 15 of the cell tray 10. Next, the cell tray 10 is inserted into a finishing station 201. During this operation, the supply connector 29 of the cell tray 10 is hydraulically connected to the delivery hydraulic connector 208 of the hydraulic system 202 of the finishing plant 200, and the return connector 30 of the cell tray 10 is connected to the return hydraulic connector 209 of the hydraulic system 202 of the finishing plant 200.

[0186] Fluid is sent to the cell tray 10 at a predetermined first temperature. The fluid is sent to the cell tray 10 via the fluid conditioner 203. This predetermined first temperature is provided by the particular finishing recipe to be performed. By way of example, if this predetermined first temperature is lower than an ambient temperature, fluid is sent to the cell tray 10 from the fluid cooler 205 whose cooling temperature is set to deliver fluid at the predetermined first temperature. If the predetermined first temperature is greater than an ambient temperature, fluid is sent to the cell tray 10 from the fluid heater 204 whose heating temperature is set to deliver fluid at the predetermined first temperature. The time at which fluid is sent from the fluid conditioner 203 to the cell tray 10 is also provided by the particular finishing recipe that is to be executed. By way of example, fluid may be sent to the cell tray 10 immediately after insertion of the cell tray 10 into the finishing station 201 or after a predetermined time interval after insertion of the cell tray 10 into the finishing station 201 .

[0187] The fluid sent to the cell tray 10 enters the fluid delivery manifold 27, passes through the plurality of fluid passage cavities 19 and reaches the fluid return manifold 28. As the fluid passes through the fluid passage cavities 19, the fluid thermally conditions the first side walls 20 and the second side walls 21 of each housing array 14 and, consequently, thermally conditions the electrochemical cells 300 contained in the housing seats 15. Indeed, it should be noted that the housing seats 15 are at least partly defined by the first side walls 20 and the second side walls 21 of each housing array 14. In other words, the first side walls 20 and the second side walls 21 of each housing array 14 at least partially delimit each housing array 15.

[0188] The fluid at the predetermined first temperature is sent to the cell tray 10 and passes through the plurality of fluid passage cavities 19 for an initial period of time provided by the particular finishing recipe to be executed.

[0189] In some cases, and in particular when an aging process is carried out, it is provided to stop sending fluid at the first predetermined temperature and then sending the cell tray 10 fluid at a second predetermined temperature higher than the first predetermined temperature. This action is implemented by setting the fluid conditioner to condition the fluid at the second predetermined temperature. The point in time at which fluid is sent at the second predetermined temperature from the fluid conditioner 203 to the cell tray 10 is provided by the particular aging recipe to be executed. By way of example, fluid at the second predetermined temperature may be sent to the cell tray 10 immediately after the suspension of sending fluid at the first predetermined temperature or after waiting for a second period of time after the suspension of sending fluid at the first predetermined temperature.

[0190] The fluid at the predetermined second temperature is sent to the cell tray 10 and passes through the plurality of fluid passage cavities 19 for a third time period provided by the particular finishing recipe to be performed.

[0191] It is evident from the above that, depending on the particular finishing recipe to be performed on the electrochemical cells, essentially any fluid temperature, essentially any fluid delivery time to the cell tray 10 and essentially any fluid delivery interruption time to the cell tray 10 can be chosen.

[0192] During the dispensing of fluid to the cell tray 10, and thus as the fluid passes through the plurality of fluid passage cavities 19, a process of at least partially finishing the electrochemical cells 300 contained in the cell tray 10 is provided.

[0193] This at least partial finishing process of the electrochemical cells 300 may involve subjecting the electrochemical cells 300 to charge-discharge cycles (e.g. in the case of a forming process) or it may involve not supplying currents to the electrochemical cells 300 (e.g. in the case of an aging process).

[0194] At the end of the at least partial finishing process of the electrochemical cells 300, the cell tray 10 is to be removed from the finishing station 201 .

[0195] This action is performed by hydraulically disconnecting the delivery connector 29 of the cell tray 10 from the delivery hydraulic connector 208 of the hydraulic system 202 of the finishing plant 200 and disconnecting the return connector 30 of the cell tray 10 from the return hydraulic connector 209 of the hydraulic system 202 of the finishing plant 200.

[0196] The method for at least partially finishing electrochemical cells provides that, if in the course of the at least partial finishing of electrochemical cells 300, the temperature of an electrochemical cell reaches the melting temperature of the material of which the housing arrays 14 are made, at least the housing seat 15 housing such an electrochemical cell 300 is flooded with the fluid of the hydraulic circuit 202. The material of which the housing arrays 14 are made is selected to have a melting temperature between 120 °C and 200 °C, more preferably between 130 °C and 180 °C, for example about 165 °C. If an electrochemical cell 300 reaches a temperature in this temperature range, it is very likely if not certain that the electrochemical cell 300 is in thermal runaway state. In this case, the action of flooding the housing seat 15 with fluid from the hydraulic circuit 202 is implemented by the at least partial melting of a portion of the first side wall 20 and / or the second side wall 21 of the housing array 14 to which the housing seat 15 containing the electrochemical cell in thermal runaway state belongs.

[0197] The at least partial melting of a portion of the first side wall 20 and / or the second side wall 21 of the housing array 14 to which the housing seat 15 containing the electrochemical cell in thermal runaway state belongs results in the fluid flowing into the fluid passage cavity 19 flooding the housing cavity 15 mitigating the consequences of the thermal runaway of the electrochemical cell.

Claims

CLAIMS1 . Method for at least partially finishing electrochemical cells (300) comprising: providing a cell tray comprising: a plurality of housing arrays (14, 104) wherein each housing array (14, 104) of said plurality of housing arrays (14, 104) comprises a plurality of housing seats (15, 105), wherein each housing seat (15, 105) is configured to contain a respective electrochemical cell (300); a plurality of fluid passage cavities (19, 109) wherein each fluid passage cavity (19, 109) of said plurality of fluid passage cavities (19, 109) is defined between two adjacent housing arrays (14, 104); a fluid delivery manifold (27, 115) and a fluid return manifold (28, 116); wherein said fluid delivery manifold (27, 115) comprises a delivery connector (29, 119) and is placed in fluid connection with said plurality of fluid passage cavities (19, 109) and wherein said fluid return manifold (28, 116) comprises a return connector (30, 120) and is placed in fluid connection with said plurality of fluid passage cavities (19, 109); inserting an electrochemical cell (300) into each housing seat (15, 105) of the cell tray; inserting said cell tray into a finishing station (201 ) of a finishing plant (200); hydraulically connecting said delivery connector (29, 119) to delivery conduits (206) of a hydraulic circuit (202) of the finishing plant (200) and hydraulically connecting said return connector (30, 120) to return conduits (207) of said hydraulic circuit (202) of the finishing plant (200); letting flow fluid from the delivery conduits (206) to the return conduits (207) of the hydraulic circuit (202) through said plurality of fluid passage cavities (19, 109); implementing an at least partial finishing process of the electrochemical cells (300) contained in said cell tray.

2. Method according to claim 1 , wherein letting fluid flow through said plurality of fluid passage cavities (19, 109) is preceded by placing said fluid at least at a predetermined first temperature and sending said fluid at said predetermined first temperature to said fluid delivery manifold (27, 115).

3. Method according to claim 1 or 2, wherein letting fluid flow through said plurality of fluid passage cavities (19, 109) is implemented while implementing an at least partial finishing process of the electrochemical cells (300) contained in said cell tray.

4. Method according to any one of the preceding claims comprising removing said cell tray from said finishing station (201 ) at the end of the at least partial finishing process of the electrochemical cells (300).

5. Method according to claim 4, wherein removing said cell tray from said finishing station (201 ) comprises hydraulically disconnecting said delivery connector (29, 119) of the cell tray from said delivery conduits (206) of the hydraulic circuit (202) of the finishing plant (200) and hydraulically disconnecting said return connector (30, 120) of the cell tray from the return conduits (207) of said hydraulic circuit (202) of the finishing plant (200).

6. Method according to any one of the preceding claims, comprising flooding at least one housing seat (15, 105) with said fluid in case a wall of said at least one housing seat (15, 105) reaches a predetermined temperature preferably comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

7. Method according to claim 6, wherein flooding at least one housing seat (15, 105) with said fluid comprises preparing said plurality of housing arrays (14, 104) with a material configured to melt at a temperature comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

8. Cell tray for at least partial finishing process of electrochemical cells (300) comprising: a plurality of housing arrays (14, 104) wherein each housing array (14, 104) of said plurality of housing arrays (14, 104) comprises a plurality of housing seats (15, 105), wherein each housing seat (15, 105) is configured to contain a respective electrochemical cell (300); a plurality of fluid passage cavities (19, 109) wherein each fluid passage cavity (19, 109) of said plurality of fluid passage cavities (19, 109) is defined between two adjacent housing arrays (14, 104); a fluid delivery manifold (27, 115) and a fluid return manifold (28, 116); wherein said fluid delivery manifold (27, 115) comprises a delivery connector (29, 119) and is placed in fluid connection with said plurality of fluid passage cavities (19, 109) and wherein said fluid return manifold (28, 116) comprises a return connector (30, 120) and is placed in fluid connection with said plurality of fluidpassage cavities (19).

9. Cell tray according to claim 8, wherein each housing seat (14, 104) comprises a top opening (16, 106) configured for the insertion of an electrochemical cell (300) and is delimited by a base abutment wall (18, 108) configured to receive restingly an electrochemical cell (300); each housing seat (15, 105) being separated from an adjacent housing seat (15, 105) of a same housing array (14, 104) by a partition septum (26, 114).

10. Cell tray according to claim 8 or 9, wherein each housing array (14, 104) comprises a first side wall (20, 110) and a second side wall (21 , 111 ); each fluid passage cavity (19, 109) being defined between said first side wall (20, 110) of a housing array (14, 104) and said second side wall (21 , 111 ) of an adjacent housing array (14, 104).11 . Cell tray according to claims 9 and 10, wherein said partition septa (26, 114), said first side wall (20, 110) and said second side wall (21 , 111 ) of a housing array (14, 104) are integral with each other.

12. Cell tray according to claim 11 , wherein all the housing arrays (104) are integral with each other.

13. Cell tray according to any one of claims 8 to 12 comprising a frame (101 ) comprising a plurality of side walls (102), a top wall (103) and a bottom lid (112), said bottom lid (112) being made integral with the frame (101 ) by hot plate welding.

14. Cell tray according to claim 9 and 13, wherein each housing seat (105) comprises a bottom through-opening (107) opposite the top opening (106); said bottom lid (112) comprising a plurality of lid openings (113) located at the bottom through-openings (107) of the housing seats (105).

15. Cell tray according to claim 10, wherein each first side wall (20) of each housing array (14) comprises a first edge (22) and a second edge (23) projecting in the direction of the second side wall (21 ) of an adjacent housing array (14); said first edge (22) of each first side wall (20) at least partially defining a top wall of a respective fluid passage cavity (19) and said second edge (23) of each firstside wall (21 ) at least partially defining a base wall of a respective fluid passage cavity (19).

16. Cell tray according to claim 15, wherein each second side wall (21 ) of each housing array (14) comprises a third edge (24) and a fourth edge (25) projecting in the direction of the first side wall (20) of an adjacent housing array (14); said third edge (24) of a second side wall (21 ) defining, in combination with said first edge (22) of the first side wall (20) of an adjacent housing array (14), said top wall of the respective fluid passage cavity (19); said fourth edge (25) of a second side wall (21 ) defining, in combination with said second edge (23) of the first side wall (20) of an adjacent housing array (14), said base wall of the respective fluid passage cavity (19).

17. Cell tray according to claim 9, wherein a first distance (D1 ) measured between said abutment base wall (18, 108) and said top opening (16, 106) of each housing seat (15, 105) is greater than 90% of a height of an electrochemical cell (300) and wherein a height of said fluid passage cavity (19, 109) is greater than 80% of said first distance (D1 ).

18. Cell tray according to claim 10, wherein said fluid delivery manifold (27, 115) is placed at a first end of said plurality of housing arrays (14, 104) and said fluid return manifold (28, 116) is placed at a second end, opposite said first end, of said plurality of housing arrays (14, 104); said first side wall (20, 110) and said second side wall (21 , 111 ) of each housing array (14, 104) developing between said fluid delivery manifold (27, 115) and said fluid return manifold (28, 116).

19. Cell tray according to any one of claims 8 to 18, wherein said fluid delivery manifold (27, 115) comprises a plurality of passage openings (31 , 121 ) each of which directly faces a respective fluid passage cavity (19, 109) and wherein said fluid return manifold (28, 116) comprises a plurality of passage openings (32, 122) each of which directly faces a respective fluid passage cavity (19, 109).

20. Cell tray according to any one of claims 8 to 19, wherein each housing array (14, 104) is made of a same material having a melting temperature comprised between 120 °C and 200 °C, more preferably comprised between 130 °C and 180 °C, for example of about 165 °C.

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