Method for assembling an instrumented battery cell and associated battery cell

Abstract

The invention relates to a method for assembling an instrumented battery cell (100), characterized in that it comprises: a step of preparing a cover (12) of a housing (10) of the cell (100) in which the cover (12) is configured to be passed through in a sealed manner by electrical connection means (21) connected to instruments (20); a step of instrumenting at least one stack (13) of electrodes, of the type comprising a stack of positive electrodes and negative electrodes separated by a separator, the instrumentation step comprising the installation of said instruments (20) on the at least one stack of electrodes to obtain at least one instrumented stack (13) of electrodes and the installation of the electrical connection means (21) connected to the instruments (20) through the cover (12);a step of inserting one or more stack(s) (13) of electrodes comprising at least the instrumented stack(s) of electrode(s) inside a cup (11) of the housing (10) of the cell; and a step of attaching the cover (12) to the cup (11) to form the sealed housing (10) of the instrumented cell (100). (Fig. 6);

Description

Title of the invention: Method for assembling an instrumented battery cell and associated battery cell Technical field of the invention

[0001] The invention relates, in general, to the technical field of energy storage devices, and relates in particular to the manufacture of instrumented cells.

[0002] The invention relates more specifically to a method of assembling an instrumented battery cell and to a battery cell obtained by this method. Prior art

[0003] Motor vehicles with electric or hybrid traction or propulsion include one or more battery modules connected to a power network to supply an electric motor (traction or propulsion).

[0004] The battery modules are grouped in a casing and together form a battery block, also often referred to by the English expression "battery pack", this casing generally containing a mounting interface and connection terminals.

[0005] Each battery module is an assembly comprising several electrochemical cells generating current by chemical reaction, for example of lithium-ion (or Li-ion), Ni-Mh, Ni-Cd or lead type.

[0006] An electrochemical cell comprises, in particular, a stack of positive electrodes connected to each other and a stack of negative electrodes connected to each other, separated by a separator, known as a "stack". The positive electrodes are connected to each other at a positive terminal, and the negative electrodes are connected to each other at a negative terminal.

[0007] It is known to assemble, in series and / or in parallel, a plurality of electrochemical cells in order to produce battery modules using an interconnection device ensuring electrical contact between the terminals of two neighboring electrochemical cells.

[0008] Each electrochemical stack is housed in a metal casing of the associated electrochemical cell. The casing is generally made of aluminum. Once the electrochemical stacks are integrated into a compartment of the casing, a plate forming a lid for the electrochemical cell is laser-welded to the compartment to create the structural connection and seal the electrochemical cell, thus closing the casing. In the remainder of this description, an electrochemical stack will also be referred to as a "stack" or "electrode stack".

[0009] Lithium-ion (Li-ion) batteries are currently the most widely used in electric vehicles. A Li-ion battery is a set of Li-ion accumulators, That is to say, the cells, connected in series or parallel in modules. The cells are cylindrical, prismatic, or pouch-type (or "pouch cells"). Recent advances in lithium-ion batteries have led to a significant reduction in battery prices and an increase in battery life.

[0010] To increase the range of electric vehicles, manufacturers have increased the onboard energy by increasing the size of the battery pack or by increasing the energy density of the batteries. The range of electric vehicles varies depending on the vehicle and driving conditions, but the energy densities of the batteries allow for driving several hundred kilometers in all cases.

[0011] To reduce charging times, manufacturers increase the power output of chargers. However, charging currents are limited by cell operating mechanisms, particularly thermal effects and aging. Beyond a certain operating range, increasing the charging current can lead to cell heating rather than a reduction in charging time. Rapid charging can cause degradation of lithium-ion cells through various mechanisms, including the deposition of metallic lithium ("lithium plating"), electrolyte degradation through the growth of a passive layer ("solid electrolyte interphase"), mechanical degradation of the electrodes, etc.

[0012] The temperature increase of Li-ion batteries can also lead to thermal runaway in one of the battery cells, with a domino effect on the other cells. Thermal runaway results in an increase in cell temperature, which causes an acceleration of exothermic reactions, generating a further increase in the internal cell temperature, with a risk of liquid electrolyte leakage, release of chemicals, fire, and explosion.

[0013] To increase the performance, safety, and durability of lithium-ion cells, it is necessary to better understand the internal parameters of the cells during operation. Indeed, to avoid stressing the cells, whether during charging or discharging, in hazardous areas, safety margins are used, particularly operating voltage ranges during charging and discharging. Another parameter that is monitored is temperature. During operation, the electrochemical processes within the cell generate heat. This heat must be efficiently dissipated by an external system.Therefore, when using lithium-ion batteries, it is advantageous to use an electronic control unit, generally called a BMS (for "Battery Management System"), which will limit the loads to optimize performance while ensuring battery safety and longevity. To do this, the system must be able to measure cell parameters in real time. make up the battery. The battery is indeed generally composed of several assembled cells and the BMS must manage all the cells of the battery.

[0014] To provide the BMS with control data, several measurements are taken on the cells or at the module level. Currently, the measurements taken generally include the external temperature of the cells, voltage, and current. However, this data is insufficient to obtain a precise picture of the phenomena occurring inside the cell and does not allow for anticipating degradation and associated risks. These measurements are taken by adding sensors to the cells (temperature, pressure, strain, acoustic sensors, etc.), but also inside the cells, using so-called internal sensors, either within the electrolyte or on the electrodes.

[0015] Even if such instrumented cells (within the cells) are not used on end-of-life vehicles, they allow for a better understanding of the internal phenomena within the cells, enabling the creation of the most realistic "digital twins" possible for realistic simulations, and thus improving the predictability of phenomena to anticipate and avoid them. The BMS can then be configured to take these most realistic results into account and improve battery management while enhancing battery safety.

[0016] Studies and research on the performance of a battery therefore depend on the accuracy of the measurement of the main internal states of the battery, such as temperature gradients during operational scenarios and / or during the manufacture of the cells (filling, electrical formation for example) or the internal ohmic thermal contribution due to the components of the connectors.

[0017] Internal thermal gradients are present in the volume region of the electrode stack, which are masked by the cell's insulating base and the aluminum housing. In active cooling scenarios, significant vertical or horizontal thermal gradients can lead to heterogeneous current densities, which limits performance and, ultimately, cell aging.

[0018] Instrumented cells are specifically designed to measure internal thermal states during relevant power loads. To ensure product representativeness, these instrumented cells must be assembled in the same way as nominal cells. Consequently, a key challenge is to propose a methodology for implementing internal cell instrumentation that does not interfere with the operation of equipment used for the design and assembly of battery prototypes.

[0019] For these reasons, among the sensors internal to instrumented cells, those for measuring temperatures have shown their relevance. Research has notably studies have been conducted to propose a method of instrumenting a cell in order to obtain cells that exhibit a functioning as close as possible to an uninstrumented cell and through which the measurements obtained are as reliable as possible.

[0020] In this regard, we know, for example, the scientific article published in 2022 in the "Journal of Energy Storage" written by a research team from the University of Warwick entitled "In-situ temperature monitoring of a lithium-ion battery using an embedded thermocouple for smart battery applications" (authors B. Gulsoy, TA Vincent, JEH Sansom, J. Marco) which relates to the in-situ temperature monitoring of a lithium-ion battery using an embedded thermocouple for smart battery applications.

[0021] One such solution involves inserting thermal sensors inside a pre-shaped cylindrical cell. This method of instrumenting battery cells has the disadvantage of potentially leading to a loss of performance or even safety problems such as an internal short circuit. Description of the invention

[0022] The invention aims to remedy all or part of the disadvantages of the prior art by proposing in particular a solution enabling the instrumentation of a cell by optimizing the implementation of the assembly steps of non-instrumented cells.

[0023] Another objective is to obtain improved reliability of the data measured inside the cell.

[0024] Another objective of the invention is to obtain a cell whose behavior during use or testing is as close as possible to the operation of a non-instrumented cell.

[0025] To this end, according to a first aspect of the invention, a method for assembling an instrumented battery cell is proposed, remarkable in that it comprises: • a preparation step for a cover of a cell housing in which the cover is configured to be passed through in a sealed manner by means of electrical connections linked to instruments; • an instrumentation step of at least one electrode stack, of the type comprising a stack of positive electrodes and negative electrodes separated by a separator, the instrumentation step comprising the installation of said instruments on the at least one electrode stack to obtain at least one instrumented electrode stack and the installation of the electrical connection means connected to the instruments through the cover; • a step of inserting one or more electrode stack(s) comprising at least the instrumented electrode stack(s) inside a cup of the cell housing; • a step of attaching the lid to the cup to form the watertight housing of the instrumented cell.

[0026] According to one embodiment, the instruments include sensors, preferably temperature sensors, even more preferably thermocouples.

[0027] According to one embodiment, the electrical connection means include electrical cables.

[0028] According to one embodiment, the housing of the instrumented cell is prismatic.

[0029] According to one embodiment, the lid preparation step includes a step of drilling through holes configured to be traversed by one of the electrical connection means.

[0030] According to one embodiment, the through orifices are each located on a connecting area forming a basin delimited by a peripheral border having a closed contour.

[0031] According to one embodiment, the lid is provided with a plurality of safety vents configured to allow degassing of the cell in the event of internal pressure exceeding a threshold pressure, the connection area being delimited by one of the safety vents of the lid.

[0032] According to one embodiment, the instrumentation step comprises: • a step of inserting the electrical connection means through the through-holes in the cover; and • a step of hermetically sealing the orifices through which the connecting means pass, preferably by applying a sealing coating.

[0033] According to one embodiment, the sealing coating comprises a sealing resin. The resin, and more generally the sealing coating, is configured so as to be compatible with the electrolyte composition of the corresponding instrumented battery cell, that is to say, the resin, or more generally the sealing coating, is composed of a material that does not degrade said electrolyte composition of the corresponding instrumented battery cell.

[0034] According to one embodiment, the instrumentation step includes a local deformation step of the electrical connection means, preferably before the hermetic sealing step of the orifices through which the connection means pass, the local deformations preferably being configured to be located on an external side of the cover, directly in the vicinity of said cover.

[0035] According to one embodiment, the local deformations of the electrical connection means extend along at least two dimensions, preferably along three dimensions, and even more preferably include a twisted portion, for example globally helical.

[0036] According to one embodiment, the hermetic sealing step of the orifices through which the connecting means pass includes a step of embedding, at least in part and preferably entirely, the local deformations of the electrical connecting means in a thickness of the sealing coating.

[0037] According to one embodiment, the assembly process includes, prior to the instrumentation step, a step of fixing the cover to collectors connected to at least one stack of electrodes.

[0038] According to one embodiment, the assembly process comprises, after the instrumentation step and before the insertion step into the cell housing cup, a folding step in which the collectors are folded so as to bring the instrumented electrode stack(s) into an insertion position inside the cell housing cup.

[0039] According to one embodiment, the cell comprises a plurality of stacks of electrodes.

[0040] According to another aspect of the invention, it relates to an instrumented battery cell remarkable in that it is made by an assembly process as described above. Brief description of the figures

[0041] Other features and advantages of the invention will become apparent from the following description, with reference to the accompanying figures, which illustrate: • [Fig.1]: a view of several successive stages of a cell assembly process known from the prior art; • [Fig. 2]: a view of a lid after a preparation step, in in which the cover is pierced by through holes configured to be traversed by an electrical connection means according to an embodiment; • [Fig. 3]: a view in which the cover is attached to collectors connected to stacks of electrodes, according to one embodiment; • [Fig. 4]: A detailed view of the cover through which electrical cables pass forming means of electrical connections configured to be connected to instruments; - [Fig. 5]: a view similar to [Fig. 4] in which a step of airtight sealing of the openings through which the connecting means were passed implementation by applying a waterproofing coating according to a method of embodiment; • [Fig. 6]: a view of part of an instrumented cell including the cover, collectors and electrode stacks in an insertion position ready to cooperate with the cell cup according to one embodiment; • [Fig.7]: a schematic view of [Fig.6]; • [Fig. 8]: a view of the instrumented battery cell according to a mode of realization ; • [Fig. 9]: a schematic view of a cell instrumented according to a mode of realization ; • [Fig. 10]: a detailed cross-sectional view of an opening through which electrical cables pass, forming means for electrical connections configured to be connected to instruments according to another embodiment; • [Fig. 11]: a detailed isometric perspective view of a lid opening according to another embodiment.

[0042] For clarity, identical or similar elements are identified by identical reference signs throughout the figures.

[0043] In the description and claims, to clarify the description and claims, the terminology longitudinal, transverse, and vertical shall be adopted without limitation, with reference to the X, Y, Z trihedron shown in the figures. Detailed description of an embodiment

[0044] An electrochemical cell 100 classically comprises a stack of positive electrodes connected to each other, and a stack of negative electrodes connected to each other, separated by a separator, known as a "stack" in Anglo-Saxon terms. The positive electrodes are connected to each other at a positive terminal, and the negative electrodes are connected to each other at a negative terminal. Each stack defines a stack 13 of electrodes.

[0045] The electrochemical cell 100 comprises a cup 11 defining a housing or internal space suitable for receiving the electrochemical stack 13 through a passage opening, and a cover 12 cooperating with a rim of the cup's passage opening to at least partially close the passage opening. In this way, once the set of electrochemical stacks 13 is integrated into the cup 11, a plate forming a cover 12 is laser-welded to the cup 11 to achieve the structural connection and sealing of the electrochemical cell 100, thereby closing the housing 10 thus formed, preferably consisting of the cup 11 and the cover 12.

[0046] The bucket 11 comprises an electrically conductive body, preferably metallic, preferably also made of aluminium.

[0047] The manufacture of a cell classically involves a number of steps.

[0048] The electrodes are first manufactured during an electrode manufacturing step This process includes an ink preparation stage to prepare inks for positive electrodes (i.e., cathodes) and negative electrodes (i.e., anodes) by mixing powder compositions of active materials, additives, and solvents in dedicated mixers. Next, the inks are coated onto strips to obtain coated strips for the production of cathodes (aluminum strips) and anodes (copper strips). This is followed by a calendering stage to obtain coated and calendered strips, and finally, a cutting and slitting stage to obtain the positive and negative electrodes.

[0049] Once the electrodes are manufactured, they are assembled by stacking or stacking 13 electrodes. The cathodes and anodes are stacked and separated by an insulating separator. For example, in the case of prismatic cells as illustrated in the figures, the electrode stacks 13 are produced by a known "Z"-folding process: the anode and cathode sheets are inserted alternately from one side and then the other into the Z-folded separator. This produces electrode stacks 13 of the type comprising a stack of positive and negative electrodes separated by a separator. The stack is secured with adhesive tape.

[0050] The cells are then assembled. The electrode stacks 13 are soldered to connectors, generally made of copper or aluminum, and then to the cell cover. The soldered stacks 13 are then protected by an insulating sleeve and inserted into the prismatic housing. The cover 12 is then soldered around its entire periphery to the cup 11 to ensure a seal.

[0051] Other steps are implemented subsequently, such as: • a curing stage where the assembled cells undergo a curing cycle to remove the last traces of moisture, • a first filling stage in which liquid electrolyte is introduced for the first time using a filling lance; • an initial electrical treatment during which the cells are subjected to initial charge and discharge cycles; • a second filling stage in which liquid electrolyte is introduced a second time to achieve the predetermined filling quantity before the associated cell is hermetically sealed; and • a second electrical treatment.

[0052] Once the cells are assembled and operational, they are then assembled into modules and connected together to form a "battery pack", that is to say an association of several modules.

[0053] The invention aims to assemble an instrumented cell using the manufacturing line for cells intended to equip vehicles.

[0054] For this purpose, a preparation step of a cover 12 is implemented in which the cover 12 is configured to be passed through in a sealed manner by electrical connection means 21 connected to instruments 20. Indeed, the instrumentation of a cell requires the installation of instruments 20 such as sensors.

[0055] In this embodiment, the sensors include thermocouples 20 which are positioned inside the housing 10 of the cell and connected from the outside by means of electrical connections 21 including electrical cables.

[0056] A thermocouple 20 is a sensor used to measure temperature. It consists of two different metals joined at one end. When the junction of the metals is heated or cooled, a variable voltage is produced, which can then be converted into a temperature reading. A resin is used to fix portions of the ends of thermocouple wires protruding from the outside of the housing 10, with associated connectors for connecting them to an electrical circuit. The resin is configured to form a watertight barrier and prevent the migration of electrolyte or a gaseous compound between the wires and a thermocouple sheath. In practice, the thermocouple wires exit the housing 10 to connect to a dedicated housing, the wires being housed in one or more sheaths. The resin on the distal end of the sheath connecting to the dedicated housing prevents the migration of electrolyte through the associated thermocouple by capillary action.A resin similar to, or even identical to, the resin of a 33-layer waterproofing coating, which will be described later, should preferably be chosen.

[0057] The preparation step of the cover 12 includes a step of drilling through holes 31 configured to be traversed by one of the electrical connection means 21 (see [Fig. 2]). Each of the through holes 31 (here three in number) is sized so that it can be traversed in a snug manner by at least one of the associated electrical cables, preferably a single cable from among the electrical cables of the instrumented cell 100.

[0058] The holes 31 are through holes such that each one passes locally through the cover between its outer and inner faces. Each of the holes 31 has a cylindrical shape. In this embodiment, given the size of the electrical cables, each of the holes 31 has a diameter of 1 mm.

[0059] Once the cover 12 has been prepared, the electrode stacks 13 are assembled with the cover 12. The electrode stacks 13 are soldered to connectors 15, generally made of copper or aluminum, depending on whether they are connected to the positive or negative terminals of the electrodes and cell. The connectors 15 are also each connected to one of the positive and negative terminals of the cover 12.

[0060] In this assembly step the connectors 15 are in an unfolded state, so that the electrode stacks 13 are superimposed on either side of the horizontally placed cover, leaving one face, preferably internal, of the cover 12 accessible in order to allow easy access to the wiring of the electrode stacks 13.

[0061] Once the cover 12 has been prepared and assembled with the electrode stacks 13, an instrumentation step for the electrode stacks 13 is carried out. During this step, the instruments 20 are installed on the electrode stacks 13 to obtain instrumented electrode stacks 13 (see [Fig. 3]), and the electrical connection means 21, consisting here of electrical cables, are also installed and connected to the instruments 20 through the cover 12.

[0062] For the installation of the instruments 20, the sensors, including here the thermocouples, are held on the edge of the stacks 13 of electrodes by means of adhesive tape compatible with the electrolyte, i.e. which is not degraded on contact with the electrolyte.

[0063] The thermocouple positioning areas 20 are chosen to allow the validation of the most realistic digital twin possible, preferably areas within the cell that are subject to the greatest temperature gradients, and to minimize the risk of internal short circuits. The regions between the different electrode stacks 13 are preferably free of instruments due to the risk of mechanical degradation of the electrodes or degradation of the thermocouple tips. Areas located on the edges of the electrode stacks 13 are therefore preferably chosen.

[0064] Regarding the installation of the electrical cables 21 connected to the instruments 20 through the cover 12, a step of inserting the electrical cables 21 through the through holes 31 in the cover 12 is implemented, followed by a step of hermetically sealing the holes 31 through which the electrical cables 21 pass by applying a sealing coating 33.

[0065] This sealing coating 33 is applied locally to the cover 12, on the side of an outer face of the cover opposite its inner face, said inner face being configured to be oriented towards the inside of the cell 100 in the instrumented position. The coating is located at the through-holes 31.

[0066] The sealing coating 33 comprises a sealing resin. In this example, the resin preferably comprises an epoxy resin compatible with an electrolyte composition, for example, an epoxy resin, and is configured to adhere locally to the surface of the cover, particularly a metallic one, to ensure the cover is sealed. The use of a resin at the through-holes 31 creates a resin plug that holds the electrical connections 21, particularly the electrical cables, in place and prevents electrolyte leakage through said holes 31.

[0067] In this example, the resin used is a 3M brand epoxy resin referenced “DP 100”.

[0068] According to another embodiment, the sealing coating 33 is silicone-based, preferably made of silicone.

[0069] According to one embodiment, the sealing coating 33 is made of epoxy material. The material forming the sealing coating 33 preferably has a hardness greater than or equal to 5 Shore D, more preferably greater than or equal to 15 Shore D, and / or less than or equal to 95 Shore D, more preferably less than or equal to 90 Shore D. Such hardness provides improved resistance to ensure sealing and withstand the stresses experienced. Such a sealing coating 33 is particularly advantageous in that it has a hardness after polymerization suitable for use in a battery cell, while also having a viscosity before polymerization sufficient to migrate into gaps and small volumes (for example, for the local deformations 22 described later). In the case of an epoxy resin, the sealing coating 33 preferably has a hardness between 80 and 85 Shore D.

[0070] To facilitate the application of this resin, the through-holes 31 are each located on a bonding zone 30 forming a basin delimited by a peripheral rim 32 having a closed contour. In particular, the cover 12 is provided with a plurality of safety vents 14, here two, each configured to allow degassing of the cell in the event of internal pressure exceeding a threshold pressure. The bonding zone 30 is thus delimited by one of the safety vents 14 of the cover 12. In such a configuration, it is not necessary to prepare the cover 12 other than by drilling the holes. Indeed, at the vent 14, the thickness of the cover 12 is locally reduced so as to be closed by a membrane of predetermined thickness.Vent 14 is delimited by a peripheral border forming a notch and which forms the peripheral border 32 of the bowl shape, the bottom of which is formed by the membrane of vent 14.

[0071] Thus, during the application of the sealing coating 33, in particular during the placement of the resin, the latter can be applied in a liquid state and the form The basin method ensures a predetermined thickness of resin once dried. The peripheral rim 32 notably constrains the resin to remain localized on the bonding zone 30. The use of a single bonding zone 30, here a single vent 14, in the shape of a bowl covering all the dedicated through-holes 31 of the lid, allows for the implementation of a single resin application step. In such a configuration, it is not necessary to implement as many hermetic sealing steps as there are through-holes 31 to be hermetically sealed.

[0072] Alternatively, if the bonding zone 30 does not correspond to a bonding zone already obtained on the lid 12, as is the case with a vent 14, the preparation step of the lid 12 may include a machining or fabrication step of a bonding zone 30. Such an embodiment is illustrated more specifically in Figures 10 and 11.In this case, it may be a basin delimited by a peripheral rim 32 having a closed contour, the bottom of which is pierced by one or more through orifices 31. In this case, an upper portion 31A of a hole delimits the basin-shaped connection area, and a lower portion is pierced by one or more through orifices 31B communicating between the interior space of the basin 31A and the inner face of the cover 12. The upper portion 31A forming the basin is configured to be sealed hermetically by the resin.

[0073] Before the application of the sealing resin 33, the instrumentation step preferably includes a local deformation step of the electrical connection means 21, in particular of a portion of each electrical cable 21 located on the outer side of the cover 12, directly in the vicinity of said cover 12. These local deformations 22 of the electrical cables 21 include a twisted portion, preferably generally helical 23, also called a "pig's tail" shape. Such a shape is obtained by a localized twist of the corresponding electrical cable 21.

[0074] In general, it should be noted that the local deformation 22 of an associated electrical cable 21 can be carried out in three dimensions, for example in the form of a helical portion 23 in "pig's tail", but also in two dimensions, for example in the form of a spiral, or a zig-zag.

[0075] During the hermetic sealing of the openings 31 through which the electrical cables 21 pass, care shall be taken to embed, at least partially and preferably entirely, the local deformations 22 of the electrical connection means 21 within a thickness of the sealing coating 33. Such local deformations 22, particularly in a generally helical shape 23 or a "pig's tail" shape, make it possible to eliminate any leaks and evaporation of electrolyte. In addition, this allows the corresponding electrical cable 21 to be secured to the cover 12. In this way, it provides a additional safety in case of unintentional pulling on the cable from the outside, which will prevent any unintentional removal of sensors 20.

[0076] The depth of the cavity or recess delimited by a vent 14 is generally relatively small. To be able to completely embed a deformed section of cable, particularly one twisted in a "pig's tail" shape, it may be desirable to apply a thicker coating. For this purpose, a band can be used, which is an added piece on the cover 12, resting against the outer face of the cover 12 so as to surround the connection area 30. The band, together with the recess of the connection area 30, forms a cavity configured to accommodate the various local deformations 22 of the electrical cables 21. By pouring the resin into this cavity in liquid form, the cavity is filled, embedding the local deformations 22 of the electrical cables 21 while perfectly conforming to the shape of the cavity, particularly in the areas where the openings 31 are located. A band 16 with a larger profile than a profile of the connection area 30 is chosen.Here formed by a 14-point vent.

[0077] In practice, this ring 16 is retained because once the resin has polymerized, it becomes bonded. To ensure that this does not affect the use of the cell, the ring 16 has a thickness configured such that a vertical height of the ring 16 is less than or equal to, preferably strictly less than, a vertical height of the electrical terminal located in its vicinity or the nearest one, so as to remain within the overall volume of the associated cell.

[0078] A band will be chosen having a thickness greater than or equal to 1 mm, preferably greater than or equal to 2 mm, and / or less than or equal to 5 mm, preferably less than or equal to 4 mm, for example equal to 3 mm.

[0079] According to one embodiment, the band is made of plastic material(s).

[0080] Once the instrumented electrode stacks 13 and the electrical wires 21 are through The lid 12 is sealed tightly using the sealing coating 33; the following steps are taken: • a folding step in which the collectors 15 are folded so as to bring the instrumented electrode stacks 13 into an insertion position inside the cup 11 of the cell housing 10 (see [Fig. 6]); then • a step of inserting one or more electrode stacks 13, including at least the instrumented electrode stack(s), into a cup 11 of the cell housing 10; then • a step of fixing the cover 12 to the cup 11 to form the sealed housing 10 of the instrumented cell 100, in particular by laser welding as seen in [Fig.1].

[0081] It appears that the invention as described offers numerous advantages, firstly, the fact that internal instrumentation of the cells in a dry state during their assembly simplifies many difficulties compared to other instrumentation. of a cell that is already formatted or assembled. The assembly process offers this advantage while ensuring its conformity with the overall assembly process of cells and modules.

[0082] The invention thus provides a simple instrumentation process for an instrumented cell, making optimal use of the manufacturing process of a normal, non-instrumented battery cell, i.e., a normal battery cell without the sensors. Therefore, to obtain the instrumented cells, the manufacturing process for normal cells is used, and only the following steps are required compared to the manufacturing of a normal, non-instrumented cell: • on the one hand, the assembly of the electrode stacks 13 to associated connectors 15 and to the previously prepared cover 12, it being understood that the cover preparation step can be carried out beforehand and in parallel so that such a step is performed in masked time relative to the assembly process of a non-instrumented cell; and • on the other hand, the step of inserting the stacks 13 of electrodes inside the cup 11 of the housing 10 of the instrumented cell.

[0083] It will be noted that in addition to the advantage of offering instrumented cells allowing the measurement of internal thermal states during uses involving relevant power demands, such instrumented cells also allow the measurement and monitoring of thermal states during manufacturing steps, in particular subsequent to the instrumentation step, preferably subsequent to the step of fixing the cover 12 to the cup 11 to form the sealed housing 10 of the instrumented cell 100.

[0084] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

[0085] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, can be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims

Demands

1. Method for assembling an instrumented battery cell (100), characterized in that it comprises: - a step of preparing a cover (12) of a housing (10) of the cell (100) in which the cover (12) is configured to be passed through in a sealed manner by electrical connection means (21) connected to instruments (20); - a step of instrumenting at least one stack (13) of electrodes, of the type comprising a stack of positive electrodes and negative electrodes separated by a separator, the instrumentation step comprising the installation of said instruments (20) on the at least one stack (13) of electrodes to obtain at least one instrumented stack (13) of electrodes and the installation of the electrical connection means (21) connected to the instruments (20) through the cover (12);- a step of inserting one or more stack(s) (13) of electrodes comprising at least the instrumented stack(s) of electrode(s) inside a cup (11) of the housing (10) of the cell; - a step of fixing the cover (12) to the cup (11) to form the sealed housing (10) of the instrumented cell (100).

2. Method of assembling an instrumented cell (100) according to claim 1, characterized in that the instruments (20) comprise sensors, preferably temperature sensors, more preferably thermocouples.

3. Method of assembling an instrumented cell (100) according to claim 1 or 2, characterized in that the electrical connection means (21) comprise electrical cables.

4. Method of assembling an instrumented cell (100) according to any one of the preceding claims, characterized in that the housing (10) of the instrumented cell (100) is prismatic.

5. A method for assembling an instrumented cell (100) according to any one of the preceding claims, characterized in that the step of preparing the cover (12) comprises a step of drilling of through holes (31) configured to be traversed each by one of the electrical connection means (21).

6. Method of assembling an instrumented cell (100) according to the preceding claim, characterized in that the through orifices (31) are each located on a connecting zone (30) forming a basin delimited by a peripheral border (32) having a closed contour.

7. Method of assembling an instrumented cell (100) according to the preceding claim, characterized in that the cover (12) is provided with a plurality of safety vents (14) each configured to allow degassing of the cell in the event of internal pressure exceeding a threshold pressure, the bonding zone (30) being delimited by one of the safety vents (14) of the cover (12).

8. Method of assembling an instrumented cell (100) according to any one of claims 5 to 7, characterized in that the instrumentation step comprises: - a step of inserting the electrical connection means (21) through the through holes (31) in the cover (12); and - a step of hermetically sealing the holes (31) through which the connection means (21) pass, preferably by applying a sealing coating (33).

9. Method of assembling an instrumented cell (100) according to the preceding claim, characterized in that the sealing coating (33) comprises a sealing resin.

10. Method of assembling an instrumented cell (100) according to any one of claims 8 or 9, characterized in that the instrumentation step includes a local deformation step of the electrical connection means (21), preferably before the hermetic sealing step of the orifices (31) through which the connection means (21) pass, the local deformations (22) being preferably configured to be located on an outside side of the cover (12), directly in the vicinity of said cover (12).

11. A method for assembling an instrumented cell (100) according to the preceding claim, characterized in that the local deformations (22) of the electrical connection means (21) extend along at least two dimensions, preferably along three dimensions, and preferably still include a twisted portion, for example globally helical (23).

12. Method of assembling an instrumented cell (100) according to any one of claims 10 or 11, characterized in that the step of hermetically sealing the orifices (31) through which the connecting means (21) pass includes a step of embedding, at least in part and preferably entirely, the local deformations (22) of the electrical connecting means (21) in a thickness of the sealing coating (33).

13. Method of assembling an instrumented cell (100) according to any one of the preceding claims, characterized in that it comprises, prior to the instrumentation step, a step of fixing the cover (12) to collectors (15) connected to at least one stack (13) of electrodes.

14. Method of assembling an instrumented cell (100) according to any one of the preceding claims, characterized in that it comprises: - after the instrumentation step; and - before the insertion step into the cup (11) of the cell housing (10), a folding step in which the collectors are folded so as to bring the instrumented electrode stack(s) into an insertion position inside the cup (11) of the cell housing (10).

15. Instrumented battery cell (100) characterized in that it is produced by an assembly process according to any one of the preceding claims.

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