Assembly structure of at least one matrix of electrochemical accumulators with at least one continuous inflatable wall in at least one plane surrounding the matrix in the plane.

Abstract

Structure for assembling at least one matrix of electrochemical accumulators with at least one continuous inflatable wall in at least one plane surrounding the matrix in the plane. The invention essentially consists of a system for assembling at least one matrix comprising at least two electrochemical accumulators (A1, A2…A42); the system (20) comprising an inflatable structure comprising at least one main inflatable wall surrounding the entire external shape of the matrix(es) according to at least one sectional plane and which, in at least one inflated state, is adapted to come into contact by matching at least the periphery of the matrix and thus tightening it. Figure for abstract: Fig.7B

Description

Title of the invention: Structure for assembling at least one matrix of electrochemical accumulators with at least one continuous inflatable wall in at least one plane surrounding the matrix in the plane. Technical field

[0001] The present invention relates to the field of electrochemical accumulators, and more particularly metal-ion accumulators.

[0002] The invention aims mainly to propose a reliable and simple solution for the assembly or disassembly of a module composed of one or more accumulator matrices within a battery system.

[0003] This module can also be considered as a battery pack or a battery itself, in the case where it is made up of one or more accumulator matrices.

[0004] Although described with reference to a Lithium-ion accumulator, the invention applies to any metal-ion electrochemical accumulator, i.e. also sodium-ion, Magnesium-ion, Aluminum-ion accumulators, etc., or more generally to any electrochemical accumulator, in particular NiCd, Pb, NiMH accumulators, etc.

[0005] Also, the invention applies to all accumulator geometries.

[0006] The invention can typically be implemented for the assembly and maintenance of new battery modules or matrices constituting them, during their initial assembly and / or during their integration into a final structure, for which they are intended, in particular in a motor vehicle. Its interest can also be exploited in the context of end of life, in a context of need for easy disassembly.

[0007] A battery module or pack according to the invention may be on-board or stationary. For example, the fields of electric and hybrid transport and grid-connected storage systems may be envisaged within the scope of the invention.

[0008] A preferred application is for electric vehicles. In the context of the invention, by electric vehicle is meant any vehicle with an electric motor. By way of non-limiting example, it may be a private vehicle, utility vehicle, a scooter, a bicycle, etc. Prior art

[0009] As illustrated schematically in Figures 1 and 2, a lithium-ion battery or accumulator usually comprises at least one electrochemical cell consisting of of an electrolyte constituent 1 between a positive electrode or cathode 2 and a negative electrode or anode 3, a current collector 4 connected to the cathode 2, a current collector 5 connected to the anode 3 and finally, a packaging 6 arranged to contain the electrochemical cell with sealing while being crossed by a part of the current collectors 4, 5.

[0010] The architecture of conventional lithium-ion batteries comprises an anode, a cathode and an electrolyte. Several types of conventional architectural geometry are known:

[0011] - a cylindrical geometry as disclosed in the US patent application 2006 / 0121348,

[0012] - a prismatic geometry as disclosed in US patents 7348098, US 7338733;

[0013] - a stacking geometry as disclosed in US patent applications 2008 / 060189, US 2008 / 0057392.

[0014] These different types of geometry are also described in publication [1].

[0015] The electrolyte component 1 may be in solid, liquid or gel form. In this In the latter form, the constituent may comprise a polymer, ceramic or microporous composite separator soaked with organic or ionic liquid electrolyte(s) that allows the movement of the Lithium ion from the cathode to the anode for charging and vice versa for discharging, thereby generating the current. The electrolyte is generally made up of a mixture of organic, non-aqueous solvents and lithium salts, as well as additives to improve performance, such as the formation and growth of electrode / electrolyte interfaces (SEI), limitation of side reactions, etc.Electrolytes can be composed of binary or ternary mixtures based on cyclic carbonates (ethylene carbonate, propylene carbonate, butylene carbonate), linear or branched (dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dimethoxyethane) in various proportions in which one or more lithium salts are dissolved, such as LiPF6, LiCF3SO3, LiFSI, LiTDI, LiDFOB, LiBF4, LiC104, etc.

[0016] The positive electrode or cathode 2 is made of lithium cation insertion materials which are generally composite, such as lithium iron phosphate LiFePO4, lithium cobalt oxide LiCoO2, lithium manganese oxide, possibly substituted, LiMn2O4 or transition metal oxide, such as lamellar materials for example, a material based on LiNixMnyCozO2 with x+y+z = 1, such as LiNi0.33Mn0.33 Coo.3302 or LiNi0.8Mno.iCoo.i02, or a material based on nickel cobalt aluminum oxide type LiNixCoyAlzO2 with x+y+z = 1, such as LiNi0.xCo0 15AI0.05CL.

[0017] The negative electrode or anode 3 is very often made of graphite carbon or Li4TiO5O12 (titanate material), possibly also based on silicon or composite formed from silicon. This negative electrode, like the positive electrode, can also contain electronically conductive additives as well as polymer additives which give it mechanical properties and electrochemical performances appropriate to the lithium-ion battery application or its implementation process.

[0018] The anode and the cathode made of lithium insertion material can be continuously deposited using a standard technique in the form of an active layer on a metal sheet or foil constituting a current collector.

[0019] The current collector 4 connected to the positive electrode is generally made of aluminum.

[0020] The current collector 5 connected to the negative electrode is generally made of copper, nickel-plated copper or aluminum. More specifically, aluminum is used for the current collectors common to positive and negative electrodes of titanate Li4Ti50i2. Copper is rather for the negative electrodes of graphite (Cgr), silicon (Si) or silicon composite (Si-C).

[0021] A lithium-ion battery or accumulator can obviously comprise a plurality of electrochemical cells which are stacked on top of each other.

[0022] Traditionally, a Li-ion battery or accumulator uses a pair of materials at the anode and cathode allowing it to operate at a high voltage level, typically between 1.5 and 4.2 Volts.

[0023] Depending on the type of application targeted, the aim is to produce either a thin and flexible lithium-ion accumulator or a rigid accumulator: the packaging is then either flexible or rigid and in the latter case constitutes a sort of case.

[0024] Flexible packaging is usually manufactured from a multi-layer composite material, consisting of a stack of aluminum layers covered by one or more polymer films laminated by bonding.

[0025] Rigid packaging is used when the intended applications are restrictive where a long service life is required, for example with much higher pressures to be supported and a stricter required level of sealing, typically less than 10 8mbar.l / s, or in environments with high constraints such as the aeronautical or space sector.

[0026] Rigid packaging (battery cases) is usually made from a metallic material, typically an aluminum alloy or stainless steel or a rigid polymer such as acrylonitrile butadiene styrene (ABS).

[0027] Rigid Li-ion battery packaging cases can be cylindrical, electrochemical cells of the batteries are wound by winding in a cylindrical geometry around a cylindrical mandrel. They can also be prismatic in shape by flattened winding.

[0028] One of the types of rigid cylindrical shaped case, usually manufactured for a high capacity Li-ion accumulator, is illustrated in [Fig.3].

[0029] A rigid prismatic shaped case is also shown in [Fig.4].

[0030] The housing 6 comprises a cylindrical side casing 7, a base 8 at one end, a cover 9 at the other end, the base 8 and the cover 9 being assembled to the casing 7. The cover 9 supports the current output poles or terminals 4, 5. One of the output terminals (poles), for example the negative terminal 5 is welded to the cover 9 while the other output terminal, for example the positive terminal 4, passes through the cover 9 with the interposition of a seal not shown which electrically insulates the positive terminal 4 from the cover.

[0031] Another possible configuration is that one of the output terminals (poles), for example the positive terminal 4 is connected to the electrochemical bundle F of the accumulator by the tab forming a collector 40 and projects and passes through the cover 9 with the interposition of a seal not shown which electrically insulates the positive terminal 4 from the cover. The other output terminal, for example the negative terminal 5, is constituted by the bottom and therefore the lateral envelope of the housing 6 which is electrically connected.

[0032] The widely manufactured rigid case type also consists of a stamped cup and a cover, welded together on their periphery. On the other hand, current collectors include a bushing with a part projecting on the top of the case and which forms a terminal also called the exposed pole of the battery.

[0033] A battery pack P is made up of a variable number of accumulators which can reach several thousand which are electrically connected in series or in parallel with each other and generally by connection bars, usually called busbars.

[0034] Reference may be made to publication [2] for the constitution of modules and battery packs.

[0035] For reasons of compactness, a mechanical integration of accumulators of cylindrical geometry with rigid casing 6 within a module or a battery pack widely retained is that illustrated in [Fig.5].

[0036] In this integration, the accumulators A1, A2...A42 are arranged parallel to each other in contact with each other by their housing 6 and in a staggered arrangement, forming a matrix which extends in the Z direction. A staggered arrangement allows for high energy density.

[0037] A pre-assembly of this matrix can most often be carried out by gluing the accumulators A1, A2...A42 to each other. The matrix comprising the accumulators forms a rigid assembly. Other arrangements than staggered are possible, for example an arrangement of the accumulators in rows aligned along X and Y. The accumulators A1-A42 illustrated have cylindrical format 6 cases, typically of format 18650, 21700, 26650, 4680. A pre-assembly by gluing involves difficulty in subsequent disassembly.

[0038] As shown in [Fig.6], a housing module M may comprise a peripheral rigid housing 10, comprising a lateral casing 11 which surrounds the accumulator matrix A1-A42, a bottom not shown which may be removable or formed integrally with the lateral casing 11 and a removable cover not shown which closes the housing.

[0039] The housing 10 is a support structure and also a protection structure for the accumulators A1-A42.

[0040] In the context of the invention, a matrix is ​​defined as a set of at least two accumulators.

[0041] The side casing 11 is for example a casing of rectangular or square cross-section with four side walls 111, 112, 113, 114 which can be assembled together or formed as a single piece.

[0042] The ends of the boxes 6 which integrate the positive 4 and negative 5 output terminals are inside the module box 10 and the electrical links and connections can be made at least partly within the box 10.

[0043] Typically, the positive 4 and negative 5 output terminals of the accumulators A1-A42 of the module M can be connected to each other, in particular by means of busbars preferably in the form of foils, in order to electrically connect the different accumulators in series and / or parallel in groups, inside the housing 10.

[0044] Usually, the aim is for a module voltage less than or equal to 60 Volts DC, so that the module manufacturing phases are not carried out under dangerous voltage.

[0045] Generally speaking, there are different types of assembly of matrices or modules in a battery pack.

[0046] An assembly can be made by screw or by tie rod. Such an assembly has several major drawbacks as follows: - the need for a specific tool per module type, - difficulty in correctly aligning the modules, - numerous screwing operations during assembly, and unscrewing during disassembly.

[0047] It is also known to assemble the modules in the form of drawers which requires the modules to be placed vertically and fixed by compression plates.

[0048] Finally, as already mentioned, the accumulators can be pre-assembled by gluing directly into a battery pack.

[0049] To compensate for dimensional tolerances during manufacturing and assembly that may be encountered in a module or in a battery pack, devices for Mechanical wedging and / or clamping have been developed to ensure wedging and / or clamping in the three directions X, Y, Z and thereby prevent the displacement of cylindrical format accumulators from the matrix within a battery module or battery pack.

[0050] We can cite patent US 10714713B2 which discloses a system for wedging prismatic accumulators within a module housing by means of a pressurized fluid and applying an elastic force which makes it possible to adapt during the aging of the module, the fluid being able to be contained in different forms of membrane arranged at different positions within the module housing.

[0051] The aforementioned known assemblies of modules or battery packs involve problems during assembly, during their lifetime and also once they are no longer in use and / or at the end of their life.

[0052] During assembly, the steps can be long, complex to implement and specific depending on the type of modules.

[0053] The assemblies produced must be able to meet certain mechanical strength and shock constraints, in particular for on-board applications such as for motor vehicles.

[0054] Furthermore, the problems of processing unused and / or end-of-life battery modules or packs, in particular the dismantling and / or recycling of their materials of interest, are increasingly pressing. The assemblies mentioned above make these dismantling phases complex (gluing, welding) and dangerous (numerous handling). It is therefore interesting to have solutions that facilitate the disassembly of batteries in order to easily isolate, for subsequent processing, the modules and accumulator matrices that constitute them.

[0055] There is therefore a need to improve the solutions for assembling the battery matrices and modules within a battery pack, to overcome the aforementioned drawbacks and this advantageously for all the assembly stages, during their lifetime and also once they are no longer in use and / or at the end of their life.

[0056] There is also a need to facilitate the disassembly of battery dies and modules.

[0057] The aim of the invention is to respond at least in part to this(these) need(s). Statement of the invention

[0058] To this end, the invention relates, in one of its aspects, to a system for assembling at least one matrix comprising at least two electrochemical accumulators; the system comprising at least one inflatable structure comprising at least one main inflatable wall surrounding the entire external shape of the matrix(es) according to at least one section plane and which, in at least one state inflated, is adapted to come into contact by fitting at least the perimeter of the matrix and thus tightening it.

[0059] By "assembly" is meant the usual meaning, namely a system for mechanically connecting several accumulator matrices together. The system according to the invention can also be implemented to clamp a single accumulator matrix, it maintains this single matrix in this case.

[0060] According to an advantageous embodiment, the inflatable structure comprises several main inflatable walls each surrounding the entire external shape of one of several matrices arranged next to each other, along the same sectional plane. In other words, a single inflatable structure can be used to clamp several accumulator matrices forming a battery pack.

[0061] According to another advantageous embodiment, the inflatable structure comprises at least one additional inflatable wall surrounding at least a portion of another periphery of the external shape of the matrix(es) along at least one plane orthogonal to the section plane. This or these additional walls make it possible to reinforce the structure of the matrix or of a battery pack and to improve its mechanical holding and / or protection properties.

[0062] According to this embodiment, the inflatable structure may comprise a single additional inflatable wall surrounding at least a portion of a single face of the outer shape of the matrix(es) along at least one plane orthogonal to the cutting plane.

[0063] The inflatable structure may also comprise two additional inflatable walls, on either side of the main wall, each surrounding at least a portion of a face of the external shape of the die(s) along at least one plane orthogonal to the section plane. This configuration, where all the faces of the dies are surrounded by the inflatable structure, is particularly advantageous for producing a direct configuration of accumulators to a battery pack, known as “cell to pack”. Indeed, this configuration allows for better support of the accumulators which are not previously fixed together.

[0064] The additional walls may be configured so that the structure is semi-open on top, which allows the structure to block the accumulators while maintaining access to the electrical connections on top of the die(s) and freeing the safety features (e.g., vents, etc.)

[0065] The inflatable structure may consist of a single envelope or comprise several separate envelopes.

[0066] Advantageously, the separate envelopes are inflated by the same fluid or different fluids.

[0067] Preferably, the inflation fluid(s) is(are) chosen from a gas, a mixture of gases, a liquid or a mixture of liquids, a gel or a mixture of gels compressible. The gas may be selected from compressed air, argon, nitrogen, krypton, carbon dioxide (CO2), a gas marketed under the name Argonite® or a gas marketed under the name Inergène®, or a mixture thereof. The liquid may be selected from water, an oil, ethylene glycol, or a mixture thereof.

[0068] According to an alternative embodiment, the material constituting the inflatable structure is chosen from a polyamide (PA), a rubber. As other constituent materials, it is also possible to envisage assemblies of neoprene with thin layers of aramids, flexible plastic or rubber materials and, more generally, any material capable of withstanding significant pressure and having good mechanical properties.

[0069] Advantageously, the material of the inflatable structure has one and / or other of the following advantageous characteristics:

[0070] - flexible to be easily deformable and adapt to possible irregularities of surface of the outer shape to be assembled,

[0071] - mechanically resistant,

[0072] - electrical insulation in the case where at least one bare part under electrical voltage of the battery matrix(es) would be in contact with the inflatable structure,

[0073] - a contact surface having a roughness to provide grip mechanical with the die(s) to be assembled.

[0074] Generally speaking, the choice of the material of the structure can be made according to the expected deformability and according to the properties and / or geometries of the dies to be mechanically maintained. For example, this choice can be made if the accumulator cases are made of plastic and / or electrically conductive material and / or with protruding parts which induce a risk of tearing of the structure...

[0075] Thus, according to an advantageous embodiment variant, the inflatable structure is coated with a thermal protection layer and / or a mechanical attachment layer with part of the external shape of the matrix(es). This may be a polyamide fabric envelope coated with a rubber layer or a Kevlar® envelope coated with an aluminum layer.

[0076] According to an advantageous embodiment, the fluid(s) is(are) one or more inerting fluids suitable for inerting the accumulators, the inflatable structure being provided with at least one safety valve suitable for opening in the event of an undesired electrochemical reaction, within the accumulator matrix(es) so as to release the inerting fluid(s) in its (their) inflated state so that it(they) is(are) expelled towards the matrix(es).

[0077] Thus, in the event of undesired reactivity of one and / or the other of the accumulators of a matrix, for example a fire, the valve of the structure opens to release the fluid that is contained and participate in the inerting of the battery matrix. The expulsion of this inerting fluid makes it possible to provide action as close as possible to each matrix.

[0078] The triggering of the opening of the valve(s) of the inflatable structure can be done:

[0079] - either passively: the valve can consist of a disc-type operculum of rupture or in a thermal pellet whose actuation is physically carried out when it reaches a threshold temperature;

[0080] - either actively, under the action of an operator or an automation by example by control with a monitoring device. The valve can thus be opened in the event of a sudden rise in temperature and / or electrical voltage of at least one accumulator in the matrix.

[0081] This method of inerting by expulsion of appropriate fluid from the interior of at least one envelope of the structure in the inflated state can advantageously complement other external inerting actions, such as a fixed automatic water extinguishing installation, also called a sprinkler or inerting by an independent CO2 circuit, etc.

[0082] The inerting fluid can be a dielectric oil, argon, nitrogen, CO2, a gas marketed under the name Argonite® or a gas marketed under the name Inergène®...

[0083] According to another advantageous embodiment, the inflation fluid(s) is(are) a heat transfer fluid(s) suitable for regulating the thermal performance of the accumulators of the matrix(es). Thus, not only does the structure have a mechanical support function but it can also act as a heat exchanger. Thus, the heat transfer fluid can circulate within the structure to ensure better cooling and thus increase the service life of the accumulator(s) of the matrix(es). Fins or walls can be added to optimize the thermalization function, in particular by distributing the fluid within the structure. It is also possible to envisage depositing one or more thermally conductive layers promoting thermal exchanges between the surface of the inflatable structure and an accumulator, such as thin metal layers, for example copper or aluminum.

[0084] According to an advantageous embodiment variant, the system comprises means for adapting the inflated state of the structure as a function of the mechanical deformations of the matrix(es) so as to keep it(them) tight. In other words, if the matrix(es) kept tight deform(s), for example in the event of aging of one or more of the accumulators of a matrix with deformation of the external envelope thereof(s), the quantity of fluid in the inflatable structure increases or decreases to ensure a constant holding force on the matrix. Generally speaking, the pressure inside the inflatable structure may be variable during the life of the battery pack, for example to adapt the holding pressure in order to absorb dimensional variations during aging. This avoids the disadvantages of the state of the art, particularly flexible packaging accumulators, which assign this pressure adaptation role either by an empty volume within the module casing, which is therefore a waste of space, or by the use of polymer cast in a module but which causes difficulties in recycling / disassembly. Control of the pressure of the structure can, for example, be ensured by the BMS of the battery pack and contribute to optimizing the operation of the latter.

[0085] According to an advantageous embodiment variant, at least part of the inflatable structure is mechanically stiffened. Stiffening all or part of the inflatable structure can allow better control of the external form factor. This stiffening can be ensured by a structuring system, such as multiple cushions, a system according to the so-called "Drop-stitch" technology. Drop stitch technology is a manufacturing method based on the principle of a three-dimensional fabric called a membrane, or skin which allows the inflation of a transportable object. This technology is characterized by filaments connecting an upper layer to a lower layer at a strict angle of 90°, which leads to a flat shape once inflated. The entire side of the Dropstitch is sealed, so that the entire object is airtight.The choice of whether or not to stiffen all or part of the structure can be made according to the desired function, for example, favoring support rather than shock absorption, etc., or according to the dimensions. On this last point, stiffening is advantageous for parts with large surfaces to avoid a significant deformation effect during inflation.

[0086] Thus, the invention essentially consists of producing a system for holding one or more battery matrices, within which the accumulators do not necessarily need to be assembled together, by an inflatable structure comprising at least one main inflatable wall surrounding the entire external shape of the matrix(es) along at least one sectional plane which, once inflated, clamps the accumulator matrix(es).

[0087] A preferred application is the integration of the inflatable structure as an assembly structure of an automotive electric vehicle pack.

[0088] The parameters of the inflatable structure, such as pressure, temperature, safety triggering, etc., can be set and controlled by the BMS of the battery pack, to optimize its performance.

[0089] Ultimately, the invention provides numerous advantages, including: - a simple, efficient and quick assembly system to set up around of one or more battery matrices forming a battery pack which replaces rigid boxes according to the state of the art; a system that can instantly adapt to any initial external shape of the battery die(s) and also in the event of a change in shape and / or deformation during operations carried out on the die(s) being held. Indeed, the quantity of fluid in the inflatable structure can be increased or decreased to maintain a constant clamping force on the die(s) to be immobilized. The deformable aspect of the inflatable structure allows it to deform and adapt to all shapes of the die(s) and / or its destination area (electric vehicle, etc.); no need to position a battery matrix in a particular way before tightening due to the inflation of the structure which adapts de facto. Thus, the structure makes it possible to limit the dimensional margins necessary for the integration of a battery pack; a system which can be implemented, in particular as a robot end effector, advantageously in a process of assembling batteries before their first operation or disassembling them at the end of their life. Indeed, the system according to the invention is universal for all battery matrices and makes it possible to avoid changing a tool specific to a type of battery module; the inflatable structure makes it possible to absorb part of the vibrations and shocks suffered by the battery pack during its use, which is advantageous for an application to a motor vehicle due to road irregularities, possible accidents, etc. In the event of an impact on the pack (accident vehicle), the inflatable structure protects all its matrices on several of their faces;

[0090] - the inflatable structure can be deflated and allow easy disassembly of the pack, without resorting to screws or glues, etc. This deflation can be of interest on several occasions or in certain circumstances, such as:

[0091] i) during use of the battery to repair / change a defective part,

[0092] ii) at the end of the first life to facilitate use in the second life by ensuring easy disassembly without risk of altering the parts,

[0093] iii) at the end of life, to facilitate recycling by simplifying dismantling;

[0094] - a system particularly suited to the disassembly process for recycling / processing of end-of-line and / or end-of-line battery matrices.

[0095] For application to a Li-ion battery module or pack, each accumulator is a Li-ion accumulator in which: - the negative electrode(s) material may be chosen from the group comprising graphite, silicon, lithium, titanate oxide Li4TiO5Oi2; - the positive electrode(s) material may be chosen from the group comprising LiFePO4, LiCoO2, LiNi0.33Mn0.33Co0.33O2.

[0096] The invention also relates to an electric vehicle comprising at least one assembly system as described previously, as a means of maintaining a battery pack.

[0097] Other advantages and characteristics of the invention will become more apparent upon reading the detailed description of examples of implementations of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings

[0098] [Fig.l] [Fig.l] is an exploded perspective schematic view showing the various elements of a lithium-ion accumulator.

[0099] [Fig.2] [Fig.2] is a front view showing a lithium-ion battery with its flexible packaging according to the state of the art.

[0100] [Fig.3] [Fig.3] is a perspective view of a lithium-ion accumulator according to state of the art with its rigid packaging consisting of a cylindrical shaped box.

[0101] [Fig.4] [Fig.4] is a perspective view of a lithium-ion accumulator according to state of the art with its rigid packaging consisting of a prismatic shaped box.

[0102] [Fig.5] [Fig.5] is a perspective view of a plurality of lithium-ion batteries ion of cylindrical geometry preassembled together according to the state of the art, forming a matrix intended for a battery module or a battery pack.

[0103] [Fig.6] [Fig.6] is a front view of a battery module according to the state of the art comprising a matrix of cylindrical accumulators according to [Fig.5] and a housing housing the matrix.

[0104] [Fig.7A], [Fig.7B] Figures 7A and 7B are schematic top views showing a first example of an inflatable structure assembly system according to the invention of a battery pack in a configuration respectively not maintained and maintained by the structure in an inflated state.

[0105] [Fig.8] [Fig.8] is a sectional view illustrating a holding system with a inflatable structure according to the invention with walls which surround only the entirety of the lateral faces of the external shapes of accumulator matrices.

[0106] [Fig.9] [Fig.9] is a sectional view illustrating a holding system with a inflatable structure according to the invention with walls which surround the entire side faces of the outer shapes of accumulator matrices and with additional walls which surround the lower face of the outer shapes of accumulator matrices.

[0107] [Fig. 10] [Fig. 10] is a sectional view illustrating a holding system with an inflatable structure according to the invention with walls which surround the entire side faces of the outer forms of accumulator matrices and with additional walls which surround the upper face of the outer forms of accumulator matrices.

[0108] [Fig. 11] [Fig. 11] is a sectional view illustrating a holding system with an inflatable structure according to the invention with walls that surround the entire side faces of the outer accumulator die shapes and with additional walls that surround both the lower and upper faces of the outer accumulator die shapes.

[0109] [Fig. 12] [Fig. 12] is a sectional view illustrating a holding system with an inflatable structure according to the invention with walls surrounding the entire side faces of the outer accumulator die shapes and with additional walls surrounding the lower face and only part of the upper face of the outer accumulator die shapes.

[0110] [Fig.l3A], [Fig.l3B], [Fig.l3C] Figures 13A, 13B and 13C are schematic sectional views illustrating the different stages of integration within a particular electric vehicle of a battery pack equipped with an assembly system according to the invention, in the initial inflated state. [YES] [Fig.l4A], [Fig.l4B], [Fig.l4C], [Fig.l4D], [Fig.l4E] Figures 14A to 14E are schematic sectional views illustrating the different stages of integration within an electric vehicle, in particular of a battery pack equipped with an assembly system according to the invention, in the initial deflated state.

[0112] [Fig. 15] [Fig. 16] Figures 15 and 16 are schematic sectional views illustrating variants of assembly systems according to the invention in which the interior of the inflatable structure forms a circuit for circulating a heat transfer fluid.

[0113] [Fig.17], [Fig.18], [Fig.19], [Fig.20], [Fig.21], [Fig.22], [Fig.23] Figures 17 to 23 are schematic sectional views illustrating variants of the support system according to the invention in which the different parts of the inflatable structure are inflated by several different fluids. Detailed description

[0114] Figures 1 to 6 relate to different examples of Li-ion accumulators, flexible packaging and rigid accumulator cases as well as an accumulator matrix for a battery pack module according to the state of the art.

[0115] These figures 1 to 6 have already been commented on in the preamble and are therefore no longer commented on below.

[0116] For the sake of clarity, the same references designating the same elements according to the state of the art and according to the invention are used for all figures 1 to 26.

[0117] Figures 7A and 7B show an example of a system for maintaining a module M of a Li-ion accumulator battery pack.

[0118] The accumulators not illustrated may be in cylindrical format cases, typically in 18650, 21700 or prismatic format or in flexible packaging.

[0119] The accumulators can be arranged in a staggered pattern, being in contact with each other by their casing. This arrangement forms a matrix of accumulators which does not need to be pre-assembled. Other arrangements than in a staggered pattern are possible, for example an arrangement of the accumulators in rows aligned along X and Y.

[0120] The ends of the accumulator boxes which integrate the positive and negative output terminals can be inside the inflatable structure according to the invention and the electrical connections and links can be made at least partly within this structure.

[0121] Typically, the positive and negative output terminals of the accumulators A1-A42 of the module M can be connected to each other, in particular by means of busbars preferably in the form of foils, in order to electrically connect the different accumulators in series and / or parallel in groups, inside the structure.

[0122] As illustrated in Figures 7A and 7B, instead of a rigid housing 10 as detailed in the preamble, the inventors have proposed an assembly system 20 with at least one inflatable structure comprising at least one main inflatable wall 201, 202.. .208 surrounding the entire external shape of each accumulator matrix Mal, Ma2.. .Ma8 along at least one XY cutting plane. The clamping force applied for each matrix is ​​ensured by inflating the structure to a constant pressure.

[0123] In the deflated state of the inflatable structure, the assembly system 20 can be easily positioned around the module M without it being necessary to dismantle all or part of the latter ([Fig.7A]). Thus in this deflated state, each of the matrices Mal-Ma8 can be formed inside one of the main walls 201-208 closed on itself. In the absence of other modules in the battery, this module may also be called a battery pack or a battery.

[0124] In at least one inflated state of the structure 20, each main wall 201-208 is adapted to come into contact by matching at least the periphery of each die and thus tightening it ([Fig.7B]). Thus, each of the dies Mal-Ma8 is tightened at least by a main wall 201-208 closed on itself and inflated under the same constant pressure.

[0125] The inflatable structure 20 may consist of a single deformable envelope or of several separate envelopes, the constituent material of which is chosen from a polyamide (PA), a rubber. The constituent material is advantageously chosen according to the geometries and / or the materials of the external shape of the clamping dies.

[0126] If one seeks to improve the thermal and / or grip properties of the structure, one can coat it with a thermal protection layer and / or a mechanical grip layer with part of the external shape of each matrix. For example, an inflatable envelope can be based on polyamide fiber fabrics and be coated with a layer of rubber and / or a layer of aluminum.

[0127] The holding system 20 can adapt to the wide variety of geometries and complex geometries of accumulator matrices that can be encountered in a battery pack.

[0128] The inflatable structure may consist solely of walls 201, 202 which bear on the lateral faces of the matrix(es), as illustrated in [Fig.8].

[0129] According to a variant illustrated in [Fig.9], it is possible to provide the inflatable structure with an additional wall forming lower faces 211, 212 to reinforce the structure of the battery pack and thus improve the properties of the pack, in particular the holding and protection of the accumulators.

[0130] According to another variant illustrated in [Fig.10], it is possible to provide the inflatable structure with an additional wall forming upper faces 221, 222 to reinforce the structure of the battery pack and thus improve the properties of the pack, in particular the maintenance and protection of the accumulators.

[0131] As shown in [Fig.l 1], it is also possible to envisage an inflatable structure 20 with additional walls forming both lower faces 211, 212 and upper faces 221, 222 of the battery pack and thus improve the properties of the pack, in particular the holding and protection of the accumulators. This structural configuration can be particularly advantageous in the case of a battery in a so-called “cell to pack” configuration because it allows better holding of the accumulators which are not previously fixed together.

[0132] [Fig. 12] illustrates an advantageous variant where the inflatable structure 20 is semi-open on the top. Such a shape makes it possible to have a self-locking structure by maintaining access to the electrical connections on the top of the matrix(es) Mal, Ma2 and by releasing the safety devices, for example the vents, etc.

[0133] Figures 13A to 13C illustrate an application of direct integration of a battery pack P into the inflatable structure 20 which holds the accumulator matrices Mal, Ma2. The concept of battery pack P then replaces the concept of module M. This battery pack P can be installed in an electric vehicle, and be integrated directly for example in a rigid location, in particular in a chassis, intended to accommodate the battery pack in several ways. In [Fig.l3B], we see that the structure 20 has been inflated or pre-inflated and the matrices Mal, Ma2 have been integrated beforehand and are maintained by the structure 20. The battery pack P is therefore directly installed in the location of the vehicle provided for this purpose, the slightly adaptable aspect of the structure can make it easier to install the pack in the vehicle and limit the dimensional margins necessary for its integration.

[0134] Figures 14A to 14E illustrate another variant of integration of a battery pack with an inflatable structure according to the invention in an electric vehicle. Here, the structure, in the deflated state, is initially installed in the location provided for this purpose in the vehicle and is therefore less bulky ([Fig. 14A]). The deflated structure is thus positioned in the vehicle. Then, the matrix(es) Mal, Ma2 are positioned in the deflated structure which is then easily deformable because it is not pressurized (Figures 14C, 14D).

[0135] The structure is inflated at the end of the operations of installing the matrices Mal, Ma2 and, where applicable, the connectors ([Fig.l4E]). The battery pack P is then assembled and operational.

[0136] This integration variant according to figures 14A to 14E makes it possible to reduce or even eliminate the dimensional margins normally required to integrate the battery pack P into the vehicle since the dimensional margins are ensured by the fact that the structure is deflated and therefore less bulky, the subsequent inflation of the structure makes it possible to perfectly adjust the elements in the location of the pack.

[0137] Figures 15 and 16 illustrate advantageous variants with a semi-open inflatable structure 20, according to which the inflatable structure is filled with a heat transfer fluid to play a heat exchanger role in addition to its structural role. The walls of the structure 20 thus define a circuit 22 for circulation of the heat transfer fluid within the structure. This makes it possible to ensure better cooling of the battery pack and thus to increase its service life.

[0138] Figures 17 to 23 illustrate alternative embodiments of the structure 20 with several separate envelopes, that is to say, whose interior volumes are distinct. These variants can make it possible to inflate the structures with fluids of different natures (Fluid 1, Fluid 2, Fluid 3), depending on the properties expected by the structure. For example, an inerting fluid, Fluid 2, can be favored on the upper faces of the structure, as shown in Figures 18 and 20. A cooling fluid, Fluid 1 or 2, can be favored on the lower and lateral faces of the structure, as shown in Figures 17 to 23.

[0139] In the previous examples, the Mal-Ma8 accumulator matrices can be produced with accumulators of either cylindrical or prismatic format; rigid or flexible.

[0140] The inventors carried out dimensioning calculations for matrices standard Mal-Ma8 accumulators.

[0141] Initially, they analyzed that the pressure applied by the structure 20 should not be too high under penalty of seeing one of the standard accumulators deform, and as a corollary risking an internal short circuit or even an explosion of at least one accumulator of a matrix.

[0142] The holding pressure is determined based on the surface area of ​​the standard Mal-Ma8 dies, which are to be maintained where appropriate for assembly purposes.

[0143] For a battery module M with dimensions equal to 1000 cm, the inventors believe that an inflation pressure of 0.2 to 0.5 bars for a structure should be sufficient to tighten the module but this value could be scalable depending on the application.

[0144] The invention is not limited to the examples which have just been described; in particular, it is possible to combine characteristics of the examples illustrated within non-illustrated variants.

[0145] Other variants and improvements may be envisaged without departing from the scope of the invention.

[0146] If in the illustrated examples, the accumulators are arranged in a staggered pattern within the matrix, any other arrangement of the accumulators in contact within the matrix can be envisaged within the scope of the invention. For example, the accumulators can be aligned along two axes. List of cited references:

[0147] [1]: Diekmann, J., Rothermel, S., Nowak, S., & Kwade, “Recycling of Lithium-Ion Batteries: The LithoRec Process” A. (2018). The LithoRec Way, pages 33-38.

[0148] [2]: Harper, G., Sommerville, R., Kendrick, E., Driscoll, L., Slater, P., Stolkin, R.,... & Anderson, P, "Recycling lithium-ion batteries from electric vehicles”. Nature, (2019). 575(7781), pages 75-86.

Claims

Claims

1. System for assembling at least one matrix comprising at least two electrochemical accumulators (A1, A2...A42); the system (20) comprising an inflatable structure comprising at least one main inflatable wall surrounding the entire external shape of the matrix(s) according to at least one cutting plane and which, in at least one inflated state, is adapted to come into contact by matching at least the periphery of the matrix and thus tightening it.

2. An assembly system according to claim 1, the inflatable structure comprising several main inflatable walls (201, 202) each surrounding the entire exterior shape of one of several matrices arranged next to each other, along the same section plane.

3. Assembly system according to claim 1 or 2, the inflatable structure comprising at least one additional inflatable wall surrounding at least a part of another periphery of the external shape of the die(s) according to at least one plane orthogonal to the cutting plane.

4. An assembly system according to claim 3, the inflatable structure comprising a single additional inflatable wall surrounding at least a portion of a single face of the outer shape of the die(s) along at least one plane orthogonal to the cutting plane.

5. Assembly system according to claim 3, the inflatable structure comprising two additional inflatable walls, on either side of the main wall, each surrounding at least part of a face of the external shape of the die(s) along at least one plane orthogonal to the cutting plane.

6. Assembly system according to one of the preceding claims, the inflatable structure being constituted by a single envelope or comprising several separate envelopes.

7. An assembly system according to claim 6, the separate envelopes being inflated by the same fluid or different fluids.

8. Assembly system according to one of the preceding claims, the inflation fluid(s) of the structure being chosen from a gas, a mixture of gases, a liquid or a mixture of liquids, a gel or a mixture of compressible gels.

9. Assembly system according to one of the preceding claims, the constituent material of the inflatable structure being chosen from a polyamide (PA), a rubber.

10. Assembly system according to claim 9, the inflatable structure being coated with a thermal protection layer and / or a mechanical bonding layer with the part of the external shape of the matrix(es).

11. Assembly system according to one of the preceding claims, the inflation fluid(s) being an inerting fluid(s) suitable for inerting the accumulators, the inflatable structure being provided with at least one safety valve suitable for opening in the event of an undesired electrochemical reaction, within the accumulator matrix(es) so as to release the inerting fluid(s) in its (their) inflated state so that it (they) is (are) expelled towards the matrix(es).

12. Assembly system according to one of the preceding claims, the inflation fluid(s) being a heat transfer fluid(s) suitable for regulating the thermal properties of the accumulators of the matrix(es).

13. Assembly system according to one of the preceding claims, comprising means for adapting the inflated state of the structure as a function of the mechanical deformations of the matrix(es) so as to keep it(them) tight.

14. Assembly system according to one of the preceding claims, at least part of the inflatable structure being mechanically stiffened.

15. Electric vehicle comprising at least one assembly system according to one of the preceding claims, as a holder for a battery pack.

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