expansion compensation system between two battery cells

Abstract

The invention relates to a mechanical system (20) for compensating for expansion between two battery elements, the system (20) comprising a jaw device (210) connected to one of the two elements and comprising a plurality of notches (215', 215''), and a toothing (220) connected to the other of the two elements and comprising one or more teeth (225', 225''), the teeth (225', 225'') being able to be engaged each in a notch of the plurality of notches (215', 215''). When the teeth (220) exert a force (F) greater than a threshold force on the jaw device (210), the notches (215', 215'') move relative to the teeth (220) to allow an incremental movement of the teeth (220) within the notches (215', 215''), then return to position to positively lock the tooth(s) (225', 225'') in the plurality of notches (215', 215''), in a direction opposite to the direction of movement. (Fig. 1)

Description

Title of the invention: Expansion compensation system between two battery cells. TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates, in general, to the technical field of prismatic batteries, pocket batteries and long batteries, particularly those intended for powering the drive motors of electric or hybrid vehicles. More specifically, it relates to a mechanical system for compensating for expansion between two battery cells. STATE OF THE PRIOR TECHNOLOGY

[0002] 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).

[0003] A battery module generally comprises an array of electrochemical cells and a module frame, the frame surrounding the array of cells. An array of cells is understood to mean a plurality of electrochemical cells stacked in a longitudinal direction of the module, along a module reference axis, and separated in pairs by separator plates, each separator plate providing electrical and thermal insulation between two adjacent cells. The electrochemical cells may be prismatic cells, pouch cells, or blade cells.

[0004] In particular, each cell in the cell assembly comprises an alternating stack of positive electrodes connected to each other and to a positive terminal of the cell, negative electrodes connected to each other and to a negative terminal of the cell, and separators each positioned between two adjacent positive and negative electrodes. The electrode stack is arranged in an internal space of the cell, delimited by a rigid metallic cell casing, where it is immersed in a liquid or solid electrolyte. The cell enables chemical reactions to be carried out to store electrical energy in chemical form and release it in electrical form. For example, the reactions within electrochemical cells can be of the lithium-ion (or Li-ion), Ni-Mh, Ni-Cd, or lead type.

[0005] By way of example only and not limitation, prismatic battery cells may have the following dimensions: • a height, measured along the module's reference axis, of approximately 70 mm; • a width, measured along a vertical axis of the module, of approximately 180 mm; and • a length, measured along a transverse axis of the module, of the order of 280 mm.

[0006] In general, the dimensions of pocket cells, long cells and prismatic cells are such that the height is smaller than the width, and the width is smaller than the length.

[0007] The module frame, which surrounds the cell assembly, comprises two end plates extending along a transverse axis of the module perpendicular to the module's reference axis, and two side plates extending parallel to the module's reference axis and connecting the two end plates. The end plates and side plates of the frame are made of metallic material(s) and are designed to be rigid.

[0008] Where appropriate, several battery modules thus formed can be grouped together in a rigid overall frame to form a battery block, this overall frame generally containing a mounting interface and connection terminals.

[0009] To ensure the structural mechanical integrity of the cells of a given module, each of the end plates of the module frame applies a compressive force on the set of cells, in a longitudinal direction of the module.

[0010] It is estimated that the pressure applied by the end plates of a module frame on the entire cell assembly is greater than 10⁴ Pa, preferably greater than 10⁵ Pa, and less than 10⁹ Pa, preferably less than 10⁸ Pa, for example equal to 10⁶ Pa. Moreover, this pressure is applied over a cell surface area of ​​approximately 10³ m². Thus, the compressive force, applied in a longitudinal direction by the end plates on the entire cell assembly, is, in order of magnitude, greater than 10 N, preferably greater than 10² N, and less than 10⁶ N, preferably less than 10⁵ N, for example equal to 10⁴ N, particularly for a liquid electrolyte technology, but may be greater, for example between 10⁶ N, or even 10⁸ N, preferably between 10⁷ N, or even 10⁸ N, particularly for a solid electrolyte technology.

[0011] However, battery cells tend to expand during operation. Two types of cell expansion are distinguished under normal operating conditions: • a reversible expansion which is caused by the charging of the cell, but which is canceled out by the discharging of the cell; • a gradual and irreversible dilation which is due to the normal functioning of the cell over a prolonged period.

[0012] However, since the battery cell casings, end plates, and side plates of the module frame are rigid, cell expansion is limited, and the battery module cannot increase in volume to accommodate these deformations. Thus, the expansion phenomenon can be accompanied by an excessive increase in pressure between and within the cells. This pressure, combined with the pressure exerted by the end plates on the entire cell assembly, tends to mechanically degrade the cells and the module, disrupting their operation and potentially causing thermal runaway reactions.

[0013] To compensate for the gradual and irreversible expansion of the cells, it is proposed, in the prior art, for example in document DE102019125382, to use a pressure-limiting element disposed between two module elements exerting pressure on each other, for example between two adjacent cells of a module or between a cell and an end plate of a module. The pressure-limiting element is designed to deform elastically with a given stiffness when the pressure exerted by one of the two module elements on the other element is less than a first predetermined threshold pressure. When the first predetermined threshold pressure is exceeded, the pressure-limiting element is capable of plastically deforming until a new equilibrium is found, and then, from this plastically deformed position, of exhibiting a new elastic deformation range, with the same stiffness as before.Thus, the pressure limiting element allows the volume occupied by the cells within the module to be gradually increased according to the expansion of the cells. The pressure limiting element can be a long spring, a spiral spring, a corrugated sheet, or even an assembly of several spring discs.

[0014] However, such a pressure limiter presents a certain technical difficulty in its implementation. Indeed, the plastic deformation of the limiter must be controlled and precisely parameterized. In the case where such a limiter is a spring, this technical solution can prove costly. Description of the invention

[0015] The invention aims to remedy all or part of the disadvantages of the prior art by proposing in particular a mechanical system that is simple to manufacture and integrate into a battery module or onto a plurality of battery cells.

[0016] To this end, according to a first aspect of the invention, a mechanical system for compensating for expansion between two battery elements, in particular a prismatic battery, is proposed, the mechanical system being remarkable in that it comprises: at least one jaw device intended to be connected to one of the two elements, the jaw device comprising a plurality of notches arranged along a reference axis of the system; and at least one toothing intended to be connected to the other of the two elements, the toothing comprising one or more teeth arranged along the reference axis of the system, the tooth or teeth of the toothing being capable of being engaged each in a notch of the plurality of notches of the jaw;and in that the mechanical system comprises at least one elastic zone such that when the teeth exert a force greater than a threshold force on the jaw device in an expansion direction along the reference axis of the system, the notches of the jaw device are able to move relative to the teeth in a retraction direction having a component perpendicular to the reference axis of the system, elastically loading the elastic zone, to allow an incremental movement of the teeth in the notches of the jaw device in the expansion direction, and then to return to position by elastically unloading the elastic zone to positively lock the tooth or teeth of the teeth in the plurality of notches, in a direction opposite to the expansion direction.

[0017] The mechanical system is intended to be positioned between two battery elements so that the reference axis of the mechanical system is parallel to the reference direction of the battery.

[0018] Preferably, the battery comprises one or more battery modules connected to a power network to supply an electric motor (traction or propulsion). A battery module herein refers to a stack of cells, in particular prismatic cells, pocket cells, or long battery cells, the cells optionally being separated in pairs by a separator plate, along a reference axis of the module. The cell stack is contained within a frame comprising two end plates perpendicular to the module's reference axis and two side plates connecting the two end plates and extending parallel to the module's reference axis. Furthermore, a prismatic battery is understood to mean any type of battery with a solid or liquid electrolyte, whose prismatic elements, in practice generally rectangular parallelepipeds, are stacked along a battery reference direction.Furthermore, each battery cell is delimited by a parallelepiped-shaped cell casing.

[0019] Thus, a battery element is understood to mean any element constituting a battery module, for example a separator plate between two cells, a cell housing wall, a frame end plate or a module frame side plate.

[0020] The mechanical system can be a system attached to the two battery elements and / or a system forming an integral part of the two battery elements.

[0021] The mechanical system according to the invention is capable of storing elastic potential energy when subjected to a force that deforms it elastically. Thus, the elastic loading of the elastic zone of the mechanical system is defined as an increase in the elastic potential energy of the mechanical system. Similarly, the elastic unloading of the elastic zone is defined as a decrease in the elastic potential energy of the mechanical system. Remarkably, the displacement of the notches relative to the teeth is obtained without plastic deformation, but solely through elastic deformations, primarily in the elastic zone, the reproducibility of which is easy to control and guarantee at low cost in mass production.

[0022] The mechanical system allows for the incremental displacement of one of the two elements relative to the other when the force threshold is exceeded; in other words, the mechanical system provides an additional volume increment to the two battery elements while maintaining sufficient pressure between them. The incremental displacement of one of the two elements relative to the other is achieved by the movement of the tooth or teeth of the denting relative to the notches of the jaw device.

[0023] Each tooth of the toothing is defined by a depth, measured in a direction parallel to the withdrawal direction, a thickness, measured in a direction parallel to the reference axis, and a width, measured in a direction perpendicular to the reference axis and perpendicular to the withdrawal axis.

[0024] Similarly, each notch of the jaw device is defined by a depth, measured in a direction parallel to the withdrawal direction, a thickness, measured in a direction parallel to the reference axis, and a width, measured in a direction perpendicular to the reference axis and perpendicular to the withdrawal axis.

[0025] Positive locking of the tooth or teeth in the plurality of notches means locking the tooth or teeth in the plurality of notches by complementary shapes, so as to prevent the loosening of the mechanical system under the effect of vibrations.

[0026] Thanks to such a combination of features, such a mechanical system has the advantage of being able to effectively compensate for the expansion of the two battery elements to ensure optimal battery operation.

[0027] According to one embodiment, the notches of the mechanical system are arranged at a constant incremental pitch relative to each other along the reference axis. The incremental pitch is defined as the smallest repeating distance of the general geometric shape of the notches, measured along the reference axis of the system, from one notch to an adjacent notch in the plurality of notches.

[0028] Furthermore, if the gear set comprises at least two teeth, the teeth of the gear set are arranged along a reference axis of the system, at a constant incremental pitch relative to each other, equal to the constant incremental pitch of the notches. In this embodiment, the incremental pitch also designates the smallest repetition distance of the general geometric shape of the tooth, measured along the reference axis of the system, between one tooth and an adjacent tooth of the gear set.

[0029] According to one embodiment, the notches have a constant depth measured in a direction parallel to the withdrawal direction. In practice, for optimal tooth function, the depth of the notches is greater than, preferably greater than, and less than, preferably less than.

[0030] According to one embodiment, each notch comprises a ramp adapted to cooperate with the tooth or teeth of the jaw assembly to move the notches of the jaw device in the retraction direction. The ramp of a notch is understood to be the surface of the notch, defined by its width and depth, and adapted to come into contact with the tooth to move it by cam action.

[0031] According to another embodiment, each tooth or teeth comprise a ramp adapted to cooperate with the jaw notches to move the jaw device notches in the retraction direction. The ramp of a tooth is understood to be the surface of the tooth, defined by its width and depth, which is adapted to come into contact with the notch to move it by cam action.

[0032] Preferably, each notch has a ramp adapted to cooperate with the tooth or teeth of the jaw assembly to move the notches of the jaw device in the retraction direction, and each tooth or teeth has a ramp adapted to cooperate with the notches of the jaw assembly to move the notches of the jaw device in the retraction direction. This configuration allows the ramp of the notches to slide against the ramp of the tooth or teeth, so as to limit friction between the tooth or teeth and the notches.

[0033] According to one embodiment, the jaw device comprises a single jaw. Optionally, when the expansion between the two battery elements is high, the jaw device comprises one or more pairs of jaws, each formed of a first jaw and a second jaw, the notches of the first jaw facing the notches of the second jaw with respect to the reference axis of the mechanical system.

[0034] According to one embodiment, the jaw and teeth are made of metallic material(s), for example: • the jaw and teeth are made of stainless steel, or; • The jaw and teeth are made of aluminum; or • The jaw and teeth are made of structural steel; or • The jaw and teeth are made of titanium.

[0035] According to one embodiment, • the teeth of the dentition are straight and the notches of the jaw device are straight; or • Advantageously, to facilitate the movement of the jaw device relative to the teeth, the teeth of the teeth have a saw-tooth shape and the notches of the jaw device have a saw-tooth shape.

[0036] According to one embodiment, the jaw device comprises: • at least one single-piece jaw on which the notches are formed, the single-piece jaw having a deformation zone, for example by bending or torsion, located at a distance from the notches along the reference axis, constituting the elastic zone; or • at least one one-piece jaw on which the notches are formed, connected to a spring capable of elastically deforming to allow the movement of the notches in the direction of withdrawal, the spring constituting the elastic zone.

[0037] Alternatively, the teeth comprise: • at least one solid toothed assembly on which the teeth are formed, the solid toothed assembly having a deformation zone, for example by bending or torsion, located at a distance from the teeth along the reference axis, constituting the elastic zone; or • at least one single-piece toothing on which the teeth are formed, connected to a spring capable of elastically deforming to allow the movement of the teeth in the direction of withdrawal, the spring constituting the elastic zone.

[0038] According to one embodiment, the movement of the tooth or teeth relative to the notches is parallel to a plane containing the projection direction of the teeth or notches and the reference axis of the system.

[0039] According to another embodiment, the movement of the tooth or teeth relative to the notches is perpendicular to a plane containing the projection direction of the teeth or notches and the reference axis of the system.

[0040] According to another aspect of the invention, it relates to a battery module, in particular a prismatic battery, comprising two battery elements and a mechanical connection system between the two battery elements, remarkable in that the mechanical system is a mechanical system as described above, whose reference axis is parallel to a reference axis of the module, the jaw device is supported on or integral with one of the two elements and the teeth are supported on or integral with the other of the two elements.

[0041] In particular, • the two battery elements are an end plate of the battery module and an end plate of a second battery module; or • The two battery components are a battery module side plate and a battery module end plate; or • the two battery elements are a first side-plate element of the battery module and a second side-plate element of the battery module; or • the two battery elements are an end plate of a battery module and an end plate of a battery cell; or • the two battery elements are a cell and an adjacent separator plate from an alternating stack of cells and separator plates of the battery module, stacked along the reference axis; or • the two battery elements are an end cell or end separator plate of an alternating stack of cells and separator plates of the battery module, stacked along the reference axis, and an end plate of a battery module frame.

[0042] Such a battery module has the advantage of adapting to the progressive expansion of the cells it comprises. Thus, the problems of excessive internal pressure and thermal runaway within the module's cells related to cell expansion are mitigated, and the lifespan of such a module is extended.

[0043] According to one embodiment, at least one of the two battery elements is capable of elastically deforming in an expansion direction along the module's reference axis, by a value greater than a maximum step between two consecutive notches of the jaw device.

[0044] According to one embodiment, the jaw device is fixed or formed as a single unit with one of the two elements, and the teeth are fixed or formed as a single unit with the other of the two elements. brief description of the figures

[0045] Other features and advantages of the invention will become apparent from the following description, with reference to the accompanying figures, which illustrate: • [Fig-1]: an exploded view of a battery module, according to a first embodiment of the invention; • [Fig.2]: an isometric view of a mechanical system for compensating expansion between two battery elements, in a disassembled position and according to a first embodiment of the invention; • [Fig.3]: a detailed view of the teeth and notches of the mechanical compensation system, according to the first embodiment of the invention; • [Fig. 4]: an isometric view of the mechanical system mounted on a module of battery, at an initial operating time of the battery module and according to the first embodiment of the invention; • [Fig. 5]: an isometric view of the mechanical system mounted on the module of battery, after an operating time greater than the initial time and according to the first embodiment of the invention; • [Fig. 6]: an isometric view of the mechanical compensation system expansion between two battery elements, according to a second embodiment of the invention.

[0046] For clarity, identical or similar elements are identified by identical reference signs throughout the figures.

[0047] 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 EMBODIMENTS

[0048] Figure 1 illustrates a battery module 10 according to a first embodiment of the invention. The battery module 10 extends along a reference axis X of the module 10 and comprises a frame 110 and a set of cells 120 contained within the frame 110 of the module 10.

[0049] In particular, the cell assembly 120 comprises a plurality of prismatic electrochemical cells 122 and a plurality of separator plates 124.

[0050] Each cell 122 comprises a stack of electrodes alternating positive electrodes, separators, and negative electrodes, stacked along a cell axis preferably parallel to the X reference axis of the module. Furthermore, each cell 122 is delimited by a parallelepiped-shaped cell housing 123, the housing 123 being made of rigid metallic material(s) and capable of elastic and plastic deformation in a direction parallel to the longitudinal X axis of the module 10.

[0051] Each of the cells 122 has a height h, measured along the longitudinal axis X of the module 10, a width 1, measured along a vertical axis Z of the module 10, and a length L, measured along a transverse axis Y of the module 10. Preferably, in a cell 122, the length L is greater than the width 1, and the width 1 is greater than the height h. By way of example, a cell 122 has: • a length L greater than or equal to 200 mm, preferably greater than or equal to 250 mm, and less than or equal to 400 mm, preferably less than or equal to 350 mm, for example equal to 280 mm; • a width 1 greater than or equal to 100 mm, preferably greater than or equal to 150 mm, and less than or equal to 300 mm, preferably less than or equal to 250 mm, for example equal to 180 mm; • a height h greater than or equal to 30 mm, preferably greater than or equal to 50 mm, and less than or equal to 100 mm, preferably less than or equal to 80 mm, for example equal to 70 mm.

[0052] Here as elsewhere in the application, the qualifiers "longitudinal", "transverse" and "vertical" have no other purpose than to identify the X, Y, Z directions on the figures, and do not describe directions with respect to the direction of gravity.

[0053] Furthermore, each of the separating plates 124 of the set of cells 120 has a length and a width respectively equal or substantially equal to the length L and the width 1 of the cells 122, and a height much less than the height h of the cells 122.

[0054] The electrochemical cells 122 and the separating plates 124 are aligned along the reference axis X of the module 10, more precisely, the cells 122 are separated two by two by a separating plate 124, thus forming a stack of cells 122 along the reference axis X of the module 10. In particular, the longitudinal ends of the stack are closed by two separating plates 124.

[0055] The frame 110 of the module 10 encloses the set of cells 120 along the longitudinal X and transverse Y directions of the module 10. In particular, the frame 110 comprises two end plates 112 extending along the transverse Y axis of the module and two side plates 114 extending along the longitudinal X axis of the module 10, the length of the side plates 114, measured transversely, being greater than the length of the end plates 112, measured longitudinally. Thus, the two end plates 112 cover the two separating plates 124 that close the stack of cells 122.

[0056] To ensure optimal operation of the battery module 10, the frame 110, and more specifically the two end plates 112, compress the cell assembly 120 longitudinally, so as to maintain sufficient contact pressure between the cells 122, throughout the entire period of use of the battery module 10.

[0057] In practice and by way of example, the contact pressure applied by the two end plates 112 on the cell assembly 120 is greater than 10⁴ Pa, preferably greater than 10⁵ Pa, and less than 10⁹ Pa, preferably less than 10⁸ Pa, for example equal to 10⁶ Pa, on a cell surface 122 of the order of 10³ m². Thus, the two end plates 112 apply a longitudinal compressive force on the cell assembly 120, the compressive force being greater than 10 N, preferably greater than 10² N, and less than 10⁶ N, preferably less than 10⁵ N, for example equal to 10⁴ N.

[0058] To maintain a constant compressive force of the two end plates 112 on the cell assembly 120, according to one embodiment of the invention, The end plates 112 and the side plates 114 are connected by a mechanical expansion compensation system 20, shown in detail in Figures 2 to 5. This mechanical system 20 allows for the longitudinal compression of the cells 122 while accommodating the progressive and irreversible expansion of the cells 122 due to their prolonged use. This irreversible expansion of the cells 122 results in an expansion of the cells 20, made possible by the deformation of the cell housings 123, along an expansion direction E illustrated in [Fig. 4]. This deformation generates a force F exerted by the cells 122 on the two end plates 112 of the module 10, also along the expansion direction E. Furthermore, the mechanical system also connects the end plates 112 to the side plates 114 of the frame 10.

[0059] Figure 2 shows the mechanical compensation system 20 in its disassembled position and according to a first embodiment of the invention. The mechanical system 20 comprises a jaw device 210 and teeth 220 extending along a reference axis X” of the system 20.

[0060] According to the first embodiment of the invention, the jaw device 210 is formed in a single piece with an end plate 112 of a battery module 10 as shown in [Fig.1], and the teeth are formed in a single piece with a side plate 114 of a battery module 10, so that the reference axis X” of the mechanical system 20 coincides with the reference axis X of the module 10.

[0061] Similarly, in this configuration, the longitudinal, transverse and vertical directions of the mechanical system 20 are coincident with the longitudinal X, transverse and vertical Z directions of said module 10.

[0062] The jaw device 210 comprises a pair of one-piece jaws 211, which include an upper jaw 211', a lower jaw 211', and a jaw base 212. The upper jaw 211', located vertically above the reference axis X”, and the lower jaw 211', located vertically below the reference axis X”, extend parallel to the reference axis X” of the device 210. The jaw base 212, which extends vertically, connects the upper jaw 211' and the lower jaw 211'.

[0063] Furthermore, the pair of jaws 211 defines an opening 213 having a rectangular shape and extending from the upper jaw 211' to the lower jaw 211" via the bottom of the jaw 212. In particular, at the opening 213, the upper jaw 211' comprises a plurality of upper notches 215' and the lower jaw 211" comprises a plurality of lower notches 215", the plurality of upper notches 215' and lower notches 215" being distributed longitudinally with respect to the mechanical system 20, along the reference axis X” of said system 20.

[0064] As shown in [Fig. 3], the upper notches 215' are spaced longitudinally by a constant incremental pitch p, the incremental pitch p denoting the smallest repetition distance of the general geometric shape of the notches 215', measured longitudinally, from one notch 215' to an adjacent notch 215' of the plurality of notches 215'. Similarly, the lower notches 215” (not shown) are spaced longitudinally by the constant incremental pitch p, so that there are as many upper notches 215' as lower notches 215” and that said notches 215', 215” are vertically aligned in pairs with respect to the reference axis X” of the mechanical system 20.

[0065] Furthermore, the upper notches 215' and lower notches 215”, have a constant contact depth hc measured in the vertical direction of the system 20, and extend over a width, measured in the transverse direction of the system 20, much greater than the depth hc.

[0066] Furthermore, as shown in [Fig. 2], according to a first embodiment of the invention, the upper notches 215' and lower notches 215" each have a general sawtooth shape and include a ramp rc. The ramp rc is inclined with respect to the reference axis X" of the system 20.

[0067] The pair of jaws 211 is made of metallic material(s), for example aluminum or stainless steel. Furthermore, the pair of jaws 211 has a deformation zone Zc, for example by bending or torsion, located at a distance from the upper notches 215' and lower notches 215”, along the reference axis X” of the system 20, the deformation zone Zc constituting an elastic zone of the jaw device 210. Preferably, the deformation zone Zc is located on a longitudinal slice of the bottom of the jaw 212 parallel to the reference axis X” of the system 20, as shown in [Fig. 2].

[0068] In practice, the upper notches 215' and lower notches 215" of the pair of jaws 211 are capable of withstanding a threshold force, applied along the reference axis X" of the system 20, greater than or equal to 104 N, preferably greater than or equal to 105 N, and less than or equal to 108 N, preferably less than or equal to 107 N, for example equal to 106 N.

[0069] The teeth 220 of the mechanical system 20 are monobloc and comprise a tooth body 221 having a parallelepiped shape complementary to the opening 213 of the pair of jaws 211, and extending along the reference axis X” of the mechanical system 20, with a superior longitudinal face 221' having a complementary shape of the upper jaw 211' and a lower longitudinal face 221” presenting a complementary shape of the lower jaw 211”.

[0070] On the upper 221' and lower 221” faces of the body 221 are formed respectively a plurality of upper teeth 225' and a plurality of lower teeth 225” arranged along the reference axis X” of the system 20. According to the embodiment shown in [Fig. 2], the teeth 220 comprise two upper teeth 215' and two lower teeth 215”.

[0071] In particular, the teeth 220 are designed to be engaged in the jaw device 210 of the mechanical system 20. More specifically, the upper teeth 225' of the teeth 220 are designed to be engaged each in an upper notch 215' of the jaw device 210, and the lower teeth 225" of the teeth 220 are designed to be engaged each in a lower notch 215" of the jaw device 210.

[0072] Thus, to allow the engagement of the teeth 220 in the jaw device: • the upper teeth 225' are spaced longitudinally by the incremental pitch p and the lower teeth 225" are spaced longitudinally by the incremental pitch p; so that there are as many upper teeth 225' as lower teeth 225" and that said teeth 225', 225" are vertically aligned two by two with respect to the reference axis X" of the mechanical system 20; • the upper teeth 225' and lower teeth 225”, have a contact depth hd, measured in the vertical direction of the system, constant and equal to the contact depth hc of the upper notches 215' and lower notches 215” of the jaw device 210; • the upper teeth 225' and lower teeth 225” extend over a width, measured in the transverse direction of the system 20, equal to the contact width of the upper notches 215' and lower notches 215” of the jaw device 210.

[0073] In addition, the upper teeth 2 2 5' and lower teeth 2 2 5" each have a general sawtooth shape, and include a ramp rd. The ramp rd is inclined with respect to the reference axis X" of the system 20, and this inclination coincides with that of the notches.

[0074] The upper 225' and lower 225" teeth of the dentition 220 are provided to be complementary to the upper 215' and lower 215" notches of the jaw device 210; thus the ramps rc of the upper 215' and lower 215" notches are able to cooperate by surface contact with the ramps rd of the upper 225' and lower 225" teeth of the dentition 220 respectively.

[0075] The teeth 220 are made of metallic material(s), preferably identical to the metallic material(s) of the jaw pair 211, for example aluminum or even in stainless steel. In addition, the pair of jaws 211 has a deformation zone Zd, for example by bending or torsion, located at a distance from the upper teeth 225' and lower teeth 225" along the reference axis X" of the system 20, the deformation zone Zd constituting an elastic zone of the teeth 220. Preferably, the deformation zone Zc is located on a longitudinal slice of the body 221 of teeth 220 parallel to the reference axis X" of the system 20, as shown in [Fig.2].

[0076] Figures 4 and 5 represent the mechanical compensation system 20 of the [Fig.1] in the mounted position, i.e. the mechanical system 20 in which the upper teeth 225' and lower teeth 225" of the teeth 220 are respectively engaged in the upper notches 215' and lower notches 215" of the jaw device 210.

[0077] In particular, [Fig.4] represents the mechanical system 20 at an initial operating time t0, which corresponds to the start of the use of the battery module 10, and [Fig.5] represents the mechanical system 20 after an operating time t1 of the battery module 10 greater than the initial time t0 and during which the cells 122 of the module 10 have undergone expansion along the longitudinal expansion direction E shown in [Fig.5].

[0078] In [Fig. 4], the two upper teeth 225' and lower teeth 225" of the dentition 220 are engaged respectively in two upper notches 215' and lower notches 215" of the jaw device 210. A distance dl separates the opening 213 of the jaw bottom 212 from the upper teeth 225' and lower teeth 225" located axially opposite the jaw bottom 212. In particular, the ramps rc of the two upper notches 215' and lower notches 215" of the device 210 are in planar contact respectively with the ramps rd of the two upper teeth 225' and lower teeth 225" of the dentition 220.

[0079] At the initial time t0, the force F applied by the cells 122 on the end plates 112 of the module 10 is less than the threshold force, so that the teeth 220 are in equilibrium with the jaw device 210, the upper teeth 225' and lower teeth 225" of the teeth 220 being locked in the upper notches 215' and lower notches 215" of the device 210 by complementarity of shapes.

[0080] Furthermore, the mechanical system 20 makes it possible to maintain the contact pressure between the cells 122 to ensure their optimal operation.

[0081] After a time tl of operation of the battery module 10, a distance d2 less than dl separates the opening 213 from the bottom of the jaw 212 of the upper teeth 225' and lower teeth 225' of the teeth 220.

[0082] During time tl, the cells 122 of the battery module 10 underwent expansion along the direction of expansion E. More precisely, to go from the configuration of module 10 at the initial time tO to the configuration of module 10 at time tl, the cells 122 of module 10 underwent four successive expansion steps.

[0083] The evolution of module 10 from the initial time t0 to an intermediate time tl' is described below, in which the cells 122 of module 10 have undergone a single dilation step.

[0084] The elastic deformation undergone by the cells 122 along the direction of expansion E is greater than the incremental pitch p that separates the two upper adjacent teeth 225' (or the incremental pitch p that separates the two lower adjacent teeth 225') of the dentition 220.

[0085] Consequently, the force F applied by the cells 122 along the direction of expansion E, i.e. the force F applied by the two upper teeth 225' and lower teeth 225" of the teeth 220 on the upper notches 215' and lower notches 215" of the jaw device 210, is greater than the threshold force and causes an elastic deformation of the deformation zone Zc of the pair of jaws 211, in particular a bending, which results in a curvature of the deformation zone Zc, along the longitudinal direction, and in a displacement of the upper notches 215' and lower notches 215" along a withdrawal direction which includes a component R perpendicular to the reference axis X" of the system 20.

[0086] Thus, by the displacement of the upper notches 215' and lower notches 215" of the jaw device 210, and therefore by the vertical separation of the upper notches 215' and lower notches 215" with respect to the reference axis X", the ramps rd of the two upper teeth 225' and lower teeth 225" of the toothing 220 slide on the corresponding ramps rc of the upper notches 215' and lower notches 215", until they reach the next ramps rc in the expansion direction E. The toothing 220 therefore moves a distance equal to an incremental pitch p, along the expansion direction E, in the opening 212 of the jaw device 210.

[0087] After the incremental displacement of the two teeth 225', 225”, the deformation zone Zc is elastically unloaded, resulting in the vertical approach of the upper notches 215' and lower notches 215” relative to the reference axis X”. The two upper 225' and lower 225” teeth of the gear 220 lock positively into the upper 215' and lower 215” notches of the device 210, i.e., the ramps rc of the two upper 215' and lower 215” notches of the device 210 return to planar contact respectively with the ramps rd of the two upper 225' and lower 225” teeth of the gear 220, and the upper 225' and lower 225” teeth of the gear 220 lock into the notches The upper 215' and lower 215” of device 210 are complementary in shape. Therefore, the mechanical system 20 cannot return to its initial state configuration t0.

[0088] After the incremental displacement of the teeth 220, the contact pressure between the cells 122 decreases, but remains at a level compatible with proper operation cells, because the incremental step is less than the deformation that would result from a complete release of the cells.

[0089] Remarkably, the incremental displacement of the teeth 220 is obtained without plastic deformation, either at the level of the teeth 220 or at the level of the jaw device 210, but only by elastic deformations, mainly at the level of the deformation zone Zc.

[0090] Figure 6 represents the mechanical system 20 according to a second embodiment of the invention. The mechanical system 20 differs from that shown in Figures 1 to 4 in that the teeth 220 comprise a plurality of teeth 221 and in that the jaw device 210 comprises a plurality of jaw pairs 211 as defined above.

[0091] In particular, all the bodies 221 are parallel to the reference axis X” of the system 20 and are vertically spaced two by two, each body 221 of the plurality of bodies 221 is engaged with a pair of jaws 211 of the plurality of pairs of jaws 211.

[0092] Moreover, the bodies 221 all have the same number of teeth 225', 225”, and the jaws have the same number of notches 215', 215”, so that an incremental displacement of one incremental step p of the dentition 220 with respect to the plurality of jaw pairs 211 is equivalent to an incremental displacement of all the teeth 225', 225” of the dentition 220 in all the notches of the plurality of jaw pairs 211.

[0093] 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.

[0094] For example, the mechanical system 20 can be similarly integrated on a pocket battery module or blade battery module.

[0095] Furthermore, according to one embodiment, the mechanical system 20 connects two battery elements, the teeth 220 being fixed or formed as a single unit with one of the two elements, and the jaw device 210 being fixed or formed as a single unit with the other of the two elements, and: • the two battery elements are an end plate 112 of battery module 10 and an end plate 112 of a second battery module 10; or • the two battery elements are a side plate 114 of battery module 10 and an end plate 112 of battery module 10; or • the two battery elements are a first side plate element 114 of battery module 10 and a second side plate element 114 of battery module 10; or • the two battery elements are an end plate 112 of a battery module 10 and an end plate 112 of a battery cell 122; or • the two battery elements are a cell 122 and an adjacent separator plate 124 of an alternating stack of cells 122 and separator plates 124 of the battery module 10, stacked along the X” reference axis; or • the two battery elements are an end cell 122 or an end separator plate 124 of an alternating stack of cells 122 and separator plates 124 of the battery module 10, stacked along the X reference axis”, and an end plate 112 of the battery module frame 110.

[0096] According to another embodiment, the teeth 225', 225" of the dentition 220 are straight and the notches 215', 215" of the jaw device 210 are straight.

[0097] According to another embodiment, the jaw device 210 comprises a single jaw on which a plurality of notches 215 are formed distributed along the reference axis X” of the system 20, and the body 221 of the teeth 220 comprises a single row of teeth 225 capable of engaging in the plurality of notches 215.

[0098] According to another embodiment, the jaw device 210 comprises: • at least one one-piece jaw, on which the notches 215 are formed, connected to a spring capable of elastically deforming to allow the movement of the notches 215 in the direction of withdrawal, the spring constituting the elastic zone.

[0099] According to another embodiment, the toothing 210 comprises: • at least one single-piece toothing on which the teeth are formed, connected to a spring capable of elastically deforming to allow the movement of the teeth in the direction of withdrawal, the spring constituting the elastic zone.

[0100] According to another embodiment, the body 221 of the teeth 220 and the opening 213 of the device 210 are cylindrical, in the sense that they have a rotational symmetry about the axis XX”.

[0101] 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 render such combinations impossible or meaningless.

Claims

1.

2.

3. Demands Mechanical system (20) for compensating for expansion between two battery elements, the mechanical system (20) being characterized in that it comprises: - at least one jaw device (210) intended to be connected to one of the two elements, the jaw device (210) comprising a plurality of notches (215', 215”), arranged along a reference axis (X”) of the system (20); and - at least one tooth (220) intended to be connected to the other of the two elements, the tooth (220) comprising one or more teeth (225', 225”) arranged along the reference axis (X”) of the system (20), the tooth or teeth (225', 225”) of the tooth (220) being able to be engaged each in a notch of the plurality of notches (215', 215”) of the jaw (210); and in that the mechanical system (20) comprises at least one elastic zone (Zc, Zd) such that when the teeth (220) exert a force (F) greater than a threshold force on the jaw device (210) in an expansion direction (E) along the reference axis (X”) of the system (20), the notches (215', 215”) of the jaw device (210) are able to move relative to the teeth (220) in a retraction direction having a component (R) perpendicular to the reference axis (X”) of the system (20), elastically loading the elastic zone (Zc, Zd), to allow an incremental movement of the teeth (220) in the notches (215', 215”) of the jaw device (210) in the expansion direction (E), and then to return to position by elastically unloading the elastic zone (Zc, Zd) to positively lock the or the teeth (225', 225") of the dentition (220) in the plurality of notches (215', 215"), in a direction opposite to the direction of expansion (E). Mechanical system (20) according to claim 1, characterized in that the notches (215', 215”) are arranged at a constant incremental pitch (p) of each other along the reference axis (X”). Mechanical system (20) according to claim 2, characterized in that the teeth (225', 225”) of the gearing (220) are arranged along a reference axis (X”) of the system (20), at an incremental pitch (p) constant to each other, equal to the incremental step (p) constant of the notches (215', 215”).

4. Mechanical system (20) according to any one of the preceding claims, characterized in that the notches (215', 215”) have a constant depth (pc) measured in a direction parallel to the withdrawal direction.

5. Mechanical system (20) according to any one of the preceding claims, characterized in that the notches (215', 215”) each have a ramp (rc) adapted to cooperate with the tooth or teeth (225', 225”) of the toothing (220) to move the notches (215', 215”) of the jaw device (210) in the retraction direction.

6. Mechanical system (20) according to any one of the preceding claims, characterized in that the tooth or teeth (225', 225”) each have a ramp (rd) adapted to cooperate with the notches (215', 215”) of the jaw (220) to move the notches (215', 215”) of the jaw device (210) in the retraction direction.

7. Mechanical system (20) according to any one of the preceding claims, characterized in that: - the jaw device (210) comprises a single jaw; or - the jaw device (210) comprises one or more pairs of jaws (211), each formed of a first jaw (211') and a second jaw (211”), the notches (215') of the first jaw (211') facing the notches (215”) of the second jaw (211”) with respect to the reference axis (X”) of the mechanical system (20).

8. Mechanical system (20) according to any one of the preceding claims, characterized in that the jaw device (210) comprises: - at least one one-piece jaw on which the notches (215', 215”) are formed, the one-piece jaw having a deformation zone (Zc), for example by bending or torsion, located at a distance from the notches (215', 215”) along the reference axis (X”), constituting the elastic zone (Zc); or - at least one one-piece jaw on which the notches (215', 215”) are formed, connected to a spring capable of elastically deforming to allow the movement of the notches (215', 215”) in the direction of withdrawal, the spring constituting the elastic zone.

9. Mechanical system (20) according to any one of the preceding claims, characterized in that the gearing (220) comprises: - at least one single-piece gearing (220) on which the teeth (225', 225”) are formed, the single-piece gearing (220) having a deformation zone (Zd), for example by bending or torsion, located at a distance from the teeth (225', 225”) along the reference axis (X”), constituting the elastic zone (Zd); or - at least one single-piece gearing (220) on which the teeth (225', 225”) are formed, connected to a spring capable of elastically deforming to allow the movement of the teeth (225', 225”) in the withdrawal direction, the spring constituting the elastic zone.

10. Battery module (10) comprising two battery elements and a mechanical system (20) for connecting the two battery elements, characterized in that the mechanical system (20) is a mechanical system (20) according to any one of the preceding claims, the reference axis (X”) of which is parallel to a reference axis (X') of the module (10), the jaw device (210) is supported on or integral with one of the two elements and the teeth (220) are supported on or integral with the other of the two elements.

11. Battery module (10) according to claim 10, characterized in that: - the two battery elements are an end plate (112) of the battery module (10) and an end plate of a second battery module (10); or - the two battery elements are a side plate (114) of the battery module (10) and an end plate (112) of the battery module (10); or - the two battery elements are a first side plate element (114) of the battery module (10) and a second side plate element (114) of the battery module (10); or - the two battery elements are an end plate (112) of a battery module (10) and an end plate (112) of a battery cell (122); or - the two battery elements are a cell (122) and an adjacent separator plate (124) of an alternating stack of cells (122) and separator plates (124) of the battery module (10), stacked along the reference axis (X”); or - the two battery elements are an end cell (122) or an end separator plate (124) of an alternating stack of cells (122) and separator plates (124) of the battery module (10), stacked along the reference axis (X”), and an end plate (124) of a frame (110) of the battery module (10).

12. Battery module (10) according to claim 10, characterized in that at least one of the two battery elements is capable of elastically deforming in an expansion direction (E) along the reference axis (X”) of the module (10), by a value greater than a maximum pitch (p) between two consecutive notches (215', 215”) of the jaw device (210).

13. Battery module (10) according to claim 10, characterized in that the jaw device (210) is fixed or formed in a monobloc manner with one of the two elements, and in that the teeth (220) are fixed or formed in a monobloc manner with the other of the two elements.

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