Improved assembled battery

Abstract

Assembled battery (1) comprising an external housing (B) itself comprising: a stack (EP) in a longitudinal stacking direction () comprising an alternation of a plurality of battery cells (CB) and a plurality of spacers (ES, ES1, ESn) movable relative to the external housing, a compression assembly comprising at least one deformable element (R1, R2, R3, R4) arranged in mechanical contact with said stack, the compression assembly being adapted, via said at least one deformable element, to compress the stack in the longitudinal direction while allowing movement in the longitudinal direction of the spacers relative to the external housing during expansion of the battery cells. [Figure 6A]

Description

Title of invention: Improved assembled battery Technical field

[0001] The present invention relates to the field of batteries assembled in the form of a battery pack. Prior art

[0002] In a conventional battery pack, multiple battery cells are stacked, connected, and combined into a single unit also called a battery pack. An assembled battery is typically used as a power source in mobile devices such as electric vehicles, hybrid vehicles, electric bicycles, etc.

[0003] In the case of electric vehicles that are driven for long periods or consume a large amount of electrical energy, the use of a plurality of battery cells assembled in a battery pack can solve the problems of power and capacity. An output voltage or current supplied to the electric vehicles can be increased by increasing the number of integrated battery cells.

[0004] In a manner known per se, battery cells expand mainly in the direction of their thickness during the charging phase of the cells. Similarly, during the discharging phase, the battery cells shrink but do not completely return to their initial dimensions.

[0005] In order to compensate for these two phenomena, it is known to use interlayers made of compressible material (typically EVA foam) to absorb the expansion of the cells while maintaining pressure on them. This solution is illustrated in Figures 1A and 1B which represent a schematic sectional view of a battery pack 10 with fully discharged and fully charged cells 11 respectively. In the battery pack 10, interlayers 12 are arranged between the cells 11 in order to absorb the expansion of the latter during their charging. Thus, the mechanical stress applied to the external casing 14 is reduced and deformation of this casing during charging cycles is limited.

[0006] However, the spacers 12 do not absorb all of the pressure resulting from the swelling of the cells and pass on part of this mechanical stress to the walls of the housing 14. Also, this housing 14 must be formed with a mechanically resistant material, generally metal, and / or must be reinforced.

[0007] The use of a metal housing involves an increase in the cost and weight of the battery pack 10.

[0008] There are other solutions known to those skilled in the art for compressing the battery cells of a battery pack and thus limiting the mechanical stress applied to the walls of the external housing.

[0009] For example, [Fig. 2] illustrates a schematic perspective view of a conventional assembled battery 100 described in application EP 1990861A1. This assembled battery 100 comprises a battery pack 23 formed by the alternating stacking of a plurality of rectangular battery cells 21 and spacers 22. To compress the battery cells 21, the assembled battery 100 comprises fixing components 24 which fix a position of the plurality of battery cells 21 and compress the stack. The fixing components 24 include a pair of end plates 25 provided on both end surfaces of the plurality of battery cells 21, and a metal strip 26 fixing the stacked battery cells 21 in a compressed state by coupling the end portions of the end plates 25. Thus, the fixing components 24 prevent the battery cells from pressing against the walls of the case.

[0010] The invention aims to overcome some of the problems identified in the solutions of the prior art by proposing an assembled battery comprising a stack formed by an alternation of battery cells and spacers and comprising a compression assembly adapted to compress the stack in the stacking direction while allowing movement of the spacers relative to the external casing in this same direction during expansion of the battery cells.

[0011] By means of a suitable structure of the compression assembly, the mechanical stresses applied by the stacking to the walls of the external casing are eliminated or greatly reduced. It is thus possible to design the assembled battery with an external casing that is less mechanically resistant, and therefore less expensive and lighter. Summary of the invention

[0012] For this purpose, an object of the invention is an assembled battery comprising an external housing itself comprising: i. a stack in a longitudinal stacking direction comprising an alternation of a plurality of battery cells and a plurality of spacers movable relative to the external housing, ii. a compression assembly comprising at least one deformable element arranged in mechanical contact with said stack, the compression assembly being adapted, via said at least one deformable element, to compress the stack in the longitudinal direction while allowing movement in the longitudinal direction of the spacers relative to the external housing during expansion of the battery cells.

[0013] According to one embodiment, an arrangement of the stack within the outer housing is such that there is a first non-zero distance in the longitudinal direction between the stack and a first wall of the outer housing and such that there is a second non-zero distance in the longitudinal direction between the stack and a second wall of the outer housing.

[0014] According to one embodiment, a first and a last layer of said stack are formed by a first spacer and a last spacer respectively. Preferably, according to this embodiment, the first spacer and the last spacer each have a mechanical structure reinforced relative to the rest of the spacers. Even more preferably, the first and the last spacer comprise a body in the general shape of a plate having two mainly opposite faces, at least one of the faces having at least one stiffening rib adapted to allow said reinforced mechanical structure of the first and the last spacer.

[0015] According to one embodiment, the spacers and the battery cells each have a body in the general shape of a plate which extends in a transverse plane substantially orthogonal to the stacking direction.

[0016] According to one embodiment, the compression assembly comprises at least one rod passing through said spacers to allow said movement in the longitudinal direction of the spacers and in which each deformable element is a cylindrical helical spring arranged around a respective rod among said at least one rod, at one end of said respective rod. Preferably, according to this embodiment, said at least one element of said compression assembly comprises four rods arranged substantially parallel to the longitudinal direction at the four ends of the spacers in order to distribute a compression force produced by the compression assembly over the stack.

[0017] According to one embodiment, said stack comprises a so-called fixed spacer having a fixed position in the longitudinal direction in the external housing, even during expansion of the battery cells, for example so that said fixed spacer is located substantially in the middle of the stack.

[0018] According to one embodiment, the assembled battery comprises spacers fixed on either side of the stack, the spacers being adapted to be in contact with an internal surface of a wall of the external housing.

[0019] According to one embodiment, each spacer comprises at least one female end piece and / or at least one male end piece and in which a male end piece of each spacer is capable of fitting and sliding inside a female end piece of an adjacent spacer to allow said movement in the longitudinal direction of the spacers.

[0020] According to one embodiment, each spacer comprises at least one trench forming, by cooperating with a battery cell adjacent to said spacer, at least one circulation channel, and in which the external housing comprises an inlet and an outlet connected to the circulation channels to allow the circulation of a heat transfer liquid between said inlet and said outlet via the circulation channels capable of cooling the battery cells.

[0021] According to one embodiment, each battery cell comprises an electrical terminal and the assembled battery comprises a first electrical connection plate arranged within the external housing, the electrical terminals being made of metal deformable by said movement in the longitudinal direction of the spacers relative to the external housing and in which the first electrical connection plate comprises openings each crossed by a respective electrical terminal, said openings being sized to allow movement of said electrical terminal following said movement in the longitudinal direction of the spacers relative to the external housing.

[0022] According to one embodiment, the spacers are made of plastic material, for example a plastic material loaded with glass fibers. Brief description of the drawings

[0023] Other characteristics, details and advantages of the invention will emerge from reading the description given with reference to the appended drawings given by way of example and which represent, respectively:

[0024] [Fig.lA] and [Fig.lB], a schematic sectional view of an assembled battery known from the prior art with respectively discharged and charged battery cells;

[0025] [Fig.2], a schematic perspective view of an assembled battery described in the prior art;

[0026] [Fig.3], a schematic sectional view of a battery assembled according to the invention;

[0027] [Fig.4A], [Fig.4B], a schematic perspective and exploded view respectively of a battery assembled according to a first embodiment of the invention;

[0028] [Fig.5], a perspective view of the stack and compression assembly of the assembled battery of the first embodiment;

[0029] [Fig.6A], [Fig.6B], a schematic sectional view of the battery assembled according to the first embodiment for discharged and charged battery cells respectively;

[0030] [Fig.7], a perspective view of the battery assembled according to the first embodiment without the external housing;

[0031] [Fig.8A], [Fig.8B], [Fig.8C], a schematic view of an example of a spacer included in a stack of a battery assembled according to the third embodiment of the invention.

[0032] In the figures, unless otherwise indicated, the elements are not to scale and identical references designate identical elements.

[0033] Furthermore, unless otherwise indicated, the optional features described in the description and the figures may be combined with each other. Description of the embodiments

[0034] First of all, the characteristics common to the batteries assembled according to the invention will be briefly described before describing in detail particular embodiments of the invention.

[0035] [Fig. 3] schematically illustrates a sectional view of a battery assembly 1 according to the invention.

[0036] The assembled battery 1 according to the invention comprises an external casing B within which is arranged a stack EP comprising an alternation of a plurality of battery cells CB and a plurality of spacers ES movable relative to the external casing B. The longitudinal direction of the stack is subsequently referenced by x.

[0037] Furthermore, the assembled battery 1 according to the invention comprises a compression assembly EC comprising at least one deformable element R adapted to compress the stack EP in the longitudinal direction x while allowing a displacement of the spacers ES relative to the external casing B in the longitudinal direction during an expansion of the battery cells. This expansion is notably caused by the charging cycles of the battery cells CB.

[0038] As will be more clearly detailed below, the aforementioned characteristics of the assembled battery 1 according to the invention allow a reduction in the mechanical stresses applied by the EP stack on the walls of the external casing B. Thus, the invention makes it possible to avoid the need to use a reinforced, heavy and expensive external casing.

[0039] In the remainder of the description, we will detail different embodiments, in particular those of the compression assembly EC, making it possible to obtain this result. It is understood that the different structures detailed in the present description and the figures are given by way of example and are intended to illustrate the invention. They should in no case be considered as limiting the scope of the invention. Various modifications and variations of the structures described will appear to those skilled in the art without departing from the scope and spirit of the invention. In particular, all equivalent means known to those skilled in the art at the date of the present invention making it possible to produce the compression assembly (and more particularly the deformable element R) are covered by the scope of the invention.

[0040] [Fig.4A] illustrates a schematic perspective view of an assembled battery 1 according to one embodiment of the invention. In [Fig.4A], the spacers ES are observable by transparency. In addition, [Fig.4B] illustrates an exploded schematic view of the assembled battery 1 of [Fig.4A]. Subsequently, the embodiment of Figures 4A and 4B is referred to as the “first embodiment”. Finally, [Fig.5] illustrates a perspective view of the stack EP and the compression assembly EC of the assembled battery of the first embodiment.

[0041] As mentioned above, the battery assembled according to the first embodiment comprises the stack EP and the compression assembly EC arranged within the external housing B.

[0042] According to the first embodiment, the EP stack comprises an alternation of battery cells CB and spacers ES which each have a body in the general shape of a plate extending in a transverse plane substantially orthogonal to the stacking direction x. The plates of the EP stack have a length in a first transverse direction 3 and a width in a second transverse direction x which is perpendicular to the first transverse direction X

[0043] It is understood that shapes other than that of the plate can be implemented for the ES spacers and / or for the CB battery cells without departing from the scope of the invention.

[0044] In the first embodiment, a first and a last layer of the EP stack are formed by a first spacer ESi and a last spacer ESn respectively. This allows better protection of the battery cells located at the ends of the stack. In addition, this allows easier implementation of the compression assembly of the invention, in particular by allowing good cooperation of the deformable element(s) with the last spacer ESn.

[0045] In the first embodiment, the compression assembly EC comprises four rods Ti, T2, T3, T4 passing through the spacers ES to allow movement in the longitudinal direction of the spacers ES. In addition, the compression assembly EC comprises four deformable elements R|-R4, each of the deformable elements being a cylindrical helical spring arranged around a respective rod, at one end of the latter.

[0046] According to an embodiment different from the first embodiment, the compression assembly EC comprises a different number of rods and / or helical springs, this number being for example adapted according to the transverse dimensions of the stack EP. In addition, other types of deformable elements can be used, for example Belleville washers when the compression forces are too great for helical springs.

[0047] According to the first embodiment, the deformable elements Ri-R4 are arranged only at one end of the stack EP so as to distribute a force of compression on the last ESn spacer. This implementation has the advantage of being simple while allowing satisfactory compression of the EP stack.

[0048] According to a second embodiment, the deformable elements are arranged on either side of the stack EP in the longitudinal direction, so as to distribute a compressive force on the first and on the last spacer ESrESn. In the second embodiment, a different number of deformable elements between the two ends is possible. This second embodiment has the advantage of allowing better compression of the stack by a potential increase in the number of deformable elements. This better compression is however obtained at the expense of a more complex implementation of the assembled battery 1 of the invention than in the first embodiment.

[0049] Preferably, in order to allow appropriate compression of the springs R1-R4, the compression assembly EC comprises elements BC fixedly mounted on a respective rod and each adapted to limit a stroke of a respective spring on one side.

[0050] As an illustrative example, in the first embodiment, the BC elements are nuts and each rod has a thread at one end to allow it to be fitted into a respective nut. Those skilled in the art will be able to implement other examples of BC elements in an obvious manner and without departing from the scope of the invention.

[0051] Thus, according to the first embodiment, an expansion of the CB cells in the longitudinal direction x causes the spacers to slide via the rods TrT4 so as to provide sufficient space for increasing the thickness of the CB cells. Simultaneously, the movement of the spacers in the external housing B causes compression of the deformable elements R1-R4 which induces a force in the opposite direction compressing the stack EP. To clarify, by "thickness of the CB cells" is meant here the dimension of the CB cells in the longitudinal direction.

[0052] In the first embodiment, it is therefore the cooperation of the deformable elements R1-R4 with the last spacer (and with the first spacer in the second embodiment) which allows the compression of the stack EP while the rods TrT4 make it possible to “guide” the movement of each spacer relative to the other spacers.

[0053] As mentioned above, this results in a reduction in the mechanical stresses on the external casing B induced by the variation in the longitudinal dimension of the EP stack.

[0054] A more precise description of the displacement of the spacers during cell expansion will be given in the description of Figures 6A and 6B.

[0055] Preferably, as illustrated in Figures 4A, 4B and 5, the four rods Ti, T2, T3, T4 of the compression assembly EC are arranged substantially parallel to the longitudinal direction, at the four ends of the spacers in order to distribute a compression force produced by the compression assembly on the stack. This allows in particular an easier arrangement of the rods through the spacers relative to the battery cells. Indeed, it is preferable for the rods to pass through the spacers but not through the battery cells. For this, in the transverse plane, the spacers are typically oversized relative to the battery cells.

[0056] According to another embodiment, the number and / or arrangement of the rods and / or springs in the plane Cj is different from that illustrated in Figures 4A, 4B and 5. Indeed, according to the invention, many different combinations of arrangements / number of springs and rods are possible to produce the desired technical effect of compressing the stack and reducing stress on the external housing. Those skilled in the art will therefore understand that the scope of the invention is not unduly limited to the illustrative example of Figures 4A, 4B and 5.

[0057] The spacers of the invention are made of a material having a Young's modulus preferably greater than 1000 Mpa and typically equal to 10000 Mpa. Indeed, unlike certain assembled batteries of the prior art (see for example figures 1A-1B), it is necessary for the spacers to have sufficient rigidity to reflect an expansion of the cells on the deformable element(s) and thus ensure compression of the EP stack. For this, the ES spacers of the invention are preferably made of plastic material, for example a plastic material loaded with glass fibers.

[0058] Similarly, in order to ensure suitable compression of the EP stack, the deformable elements of the invention have a shear modulus preferably between 2500 daN / mm2 and 15000 daN / mm2 and even more preferably between 4000 daN / mm2 and 10000 daN / mm2.

[0059] These Young's modulus and shear modulus values ​​are adapted to a typical deformation of battery cells during their charging cycles.

[0060] Preferably, when the first spacer ESi and the last spacer ESn respectively form the first and last layers of the stack EP, they each have a mechanical structure reinforced relative to the rest of the spacers. Indeed, these two spacers ESi and ESn then undergo the majority of the mechanical stresses generated by the compression assembly EC. According to the first embodiment, to allow this mechanical reinforcement, the spacers ESi and ESn have stiffening ribs N.

[0061] By way of non-limiting example, in the illustration of Figures 4A, 4B and 5, the spacers ESi and ESN have ribs along the first transverse direction (along the direction )') and ribs along the second transverse direction (along the direction s).

[0062] As visible in Figures 4B and 5, the assembled battery 1 according to the invention preferably comprises ET spacers making it possible to separate the stack from the internal wall of the housing. For this, the ET spacers are for example made of plastic and are fixed on either side of the stack in the second transverse direction, so as to be in contact with an internal surface of a wall of the external housing. The number of ET spacers and their arrangement in the plane (x-^) illustrated in Figures 4B and 5 is not limiting and depends in particular on the dimensions of the stack in the plane (x^) and the mass of the stack.

[0063] Figures 6A and 6B show a schematic sectional view of the battery assembled according to the first embodiment, for a section made along the plane (xz) passing through the rods Ti and T2.

[0064] More specifically, [Fig.6A] illustrates the assembled battery 1 in which the CB cells are fully discharged. In other words, in the illustration of [Fig.6A], the CB cells have a minimal thickness.

[0065] In contrast, in the illustration of [Fig.6B], the assembled battery 1 comprises CB cells which are fully charged and which therefore have a maximum thickness.

[0066] As illustrated in Figures 6A and 6B, according to certain embodiments, the compression assembly EC and the arrangement of the stack EP within the external housing are adapted so that the first and second spacers do not transmit any mechanical stress to the external housing in the longitudinal direction. This condition must essentially be verified when the cells are loaded and have a maximum thickness.

[0067] In other words, in these embodiments, there is a first non-zero distance dv in the longitudinal direction between the stack and a first wall Pi of the external housing and there is a second non-zero distance d2 in the longitudinal direction between the stack and a second wall P2 of the external housing. The two distances d1 and d2 are shown in Figures 6A and 6B. As an illustrative example, in Figures 6A and 6B, the two walls Pi and P2 extend along a transverse plane substantially orthogonal to the longitudinal direction.

[0068] Comparing Figures 6A and 6B, it is naturally observed that the springs Rb R2 are more compressed in the longitudinal direction when the cells CB are loaded (Figure 6B) than unloaded (Figure 6A) taking into account the expansion of the cells. For the same reason, the distances d2 and d2 are smaller when the cells CB are loaded than unloaded.

[0069] In order to distribute the longitudinal displacement of the spacers on both sides of the stack, the assembled battery of the invention preferably comprises a fixed spacer EF having a fixed position in the longitudinal direction in the external housing, even during expansion of the battery cells. Preferably, in order to best distribute the displacement of the spacers, the fixed spacer is located substantially in the middle of the stack or at the position of any of the movable spacers. Alternatively, the fixed spacer may be located at the position of any of the movable spacers in the longitudinal direction in the external housing.

[0070] By way of non-limiting example, in the embodiment of FIGS. 6A and 6B, the position of the fixed spacer EF in the housing is fixed longitudinally by means of grooves RL formed on the internal wall of the housing. These grooves extend for example in the first transverse direction y and have dimensions in the plane ( adapted to allow cooperation with the fixed spacer EF such that the latter cannot move longitudinally in the housing.

[0071] A first part A of the mobile spacers located to the left of the fixed spacer EF is defined in Figures 6A and 6B. Similarly, a second part B of the mobile spacers located to the right of the fixed spacer EF is defined in Figures 6A and 6B.

[0072] According to the first embodiment, as illustrated in figures 6A and 6B, each rod is preferentially implanted in a respective IT insert arranged in the first spacer ESi so that the rods are integral with the first spacer ES i-

[0073] Thus, when the group A of spacers moves longitudinally to the left (in the direction of the arrow FA) because of the swelling of the cells located between the spacers of the group A, the rods TrT4 follow this movement and also move to the left. The direction of movement is caused by the presence of the fixed spacer EF to the right of the group A. Given this movement of the rods TrT 4, the elements BC - mounted fixed on the rods - come to compress the springs R1-R4 in this same direction FA.

[0074] Simultaneously, group B of spacers slides in the opposite direction to group A (according to arrow FB) and also compresses springs R|-R4sc in direction FB.

[0075] Thus, by means of a suitable arrangement of the fixed spacer EF, it is possible to distribute the longitudinal displacement of the spacers on either side of the fixed spacer EF.

[0076] Preferably, the structure of the spacer(s) cooperating with the springs to compress the stack is adapted to guide a stroke of the springs during their compression in the longitudinal direction. Thus, a com optimal mechanical pressure along the longitudinal direction of the stack via the springs. For this, according to the embodiment of Figures 6A and 6B, the last spacer ESi, ESN each has several recesses illustrated by the references RFI, RF2. Each recess RFI, RF2 is associated with a respective spring and has dimensions and an arrangement adapted so as to guide, in the recess, the stroke of the respective spring during its compression along the longitudinal direction.

[0077] [Fig.7] shows a perspective view of the assembled battery 1 according to the first embodiment without the external housing.

[0078] The assembled battery of [Fig.7] comprises a first electrical connection plate PCI for making a first part of the electrical connections between the battery cells CB. The plate PCI also makes it possible to make the output BS and inlet BA electrical connections and the electrical connector tip CC for the control electronics of the assembled battery 1.

[0079] A second electrical plate PC2 (not shown in [Fig.7] but visible in [Fig.4B]) is arranged on the opposite side of the stack relative to the first plate PCI, to make a second part of the electrical connections between the battery cells CB. The connection plates PCI, PC2 are mounted fixed in the external housing B.

[0080] As illustrated in Figures 5 and 7 in particular, each battery cell CB comprises an electrical terminal CE and, preferably, the electrical connection plates PCI, PC2 comprise openings each crossed by a respective electrical terminal. Bus bars BB are then fixed on the electrical connection plates to electrically connect the electrical terminals of two adjacent CB cells. Thus, the two connection plates allow suitable series mounting of the battery cells via the bus bars BB.

[0081] In order to tolerate the displacement of cells in the longitudinal direction caused by the displacement of the spacers, it is advantageous for the CE electrical terminals to be deformable. In other words, the CE electrical terminals are made of a metal that can be deformed by the displacement in the longitudinal direction of the spacers in the external housing B. For example, the terminals are made of aluminum.

[0082] However, it is preferable to avoid excessive deformation of the CE electrical terminals when the cells are moved relative to the housing. Indeed, in an extreme case of deformation, it would be possible for an electrical terminal to break, thus compromising the operation of the assembled battery. To prevent this, each opening provided in a PCI or PC2 electrical connection plate is sized to allow movement of the electrical terminal in the opening through which it passes when moving in the longitudinal direction of the cells by relative to the external housing. To clarify, by "displacement of the electrical terminal in the opening it passes through" we mean here a displacement in the longitudinal direction of the electrical terminal within the opening it passes through without the terminal being deformed by the edges of the opening.

[0083] [Fig.7] further illustrates an inlet EL to allow the circulation of a heat transfer liquid capable of cooling the battery cells (see further in the description of figures 8B and 8C).

[0084] According to the invention, numerous possibilities are conceivable as to the means(s) allowing movement of the spacers relative to the external housing in the longitudinal direction.

[0085] Thus, according to the first embodiment and as illustrated in Figures 4A to 7, the rods passing through the spacers allow this movement of the spacers while guaranteeing good mechanical stability.

[0086] Alternatively, according to a third embodiment of the invention compatible with the first embodiment of the invention, the movement of the spacers relative to the external housing is enabled by a telescopic mounting of the spacers.

[0087] Figures 8A to 8C schematically illustrate an example of an ES spacer included in an EP stack of a battery assembled according to the third embodiment of the invention. In this example, each ES spacer has a body in the general shape of a plate and comprises four female TF ends and four male TM ends distributed preferentially at the four ends of the spacer. Each male TM end of each ES spacer is capable of fitting and sliding inside a female TF end of an adjacent spacer to allow movement in the longitudinal direction of the spacers during expansion of the CB cells.

[0088] In the third embodiment, any shape of the male and female tips is conceivable as long as a telescopic assembly between the male and female tips is possible. In addition, the number of male and female tips and their arrangement illustrated in Figures 8A to 8C are given as a non-limiting example. Other possibilities will become obvious to those skilled in the art without departing from the scope of the invention.

[0089] As mentioned above, the third embodiment of the invention is compatible with the first embodiment of the invention. In other words, according to a fourth embodiment, the movement of the spacers relative to the external housing is permitted both by the telescopic mounting of the spacers between them and by the rods passing through the spacers. Thus, optimal mechanical stability of the stack is obtained during a variation of its longitudinal dimension. The assembled battery 1 is then more mechanically robust and more resistant to shocks and vibrations.

[0090] According to the fourth embodiment, preferably each female end piece of each spacer opens onto a respective male end piece of said spacer, so as to form a hollow cylindrical portion that a rod is able to pass through. Thus, each rod passes through multiple hollow cylindrical portions formed by the male ends and the female ends of the spacers which facilitate the movement of the spacers in the longitudinal direction thanks to their telescopic mounting.

[0091] Furthermore, as illustrated in Figures 8B and 8C, spacers ES of the assembled battery 1 of the invention preferably have at least one trench T. Each trench T forms, by cooperation with an adjacent battery cell, at least one circulation channel for a heat transfer liquid capable of cooling the battery cells. To allow the circulation of the heat transfer liquid, the external housing comprises an inlet EL (shown in Figures 4A, 4B and 7) and an outlet SL (not shown) connected to the circulation channels.

[0092] In order to prevent the heat transfer fluid from circulating elsewhere than in the circulation channels, the assembled battery preferably comprises a seal JE. As illustrated in [Fig.4B], the seal is arranged between the inlet EL and the stack EP and in particular makes it possible to prevent the heat transfer fluid from circulating in the space between the stack and the wall of the housing formed by the spacers.

[0093] By way of non-limiting example, in the example of Figures 8B and 8C, each spacer ES comprises two trenches T which extend in the first transverse direction. It is understood that a different number of trenches T is possible without departing from the scope of the invention.

Claims

Claims

1. Assembled battery (1) comprising an external housing (B) itself comprising: - a stack (EP) in a longitudinal stacking direction (A) comprising an alternation of a plurality of battery cells (CB) and a plurality of spacers (ES, ESi, ESn) movable relative to the external housing, - a compression assembly (EC) comprising at least one deformable element (R, Rb R2, R3, R4) arranged in mechanical contact with said stack, the compression assembly being adapted, via said at least one deformable element, to compress the stack in the longitudinal direction while allowing movement in the longitudinal direction of the spacers relative to the external housing during expansion of the battery cells.

2. An assembled battery according to claim 1, wherein an arrangement of the stack within the outer casing is such that there is a first non-zero distance (r / j) in the longitudinal direction between the stack and a first wall (Pi) of the outer casing and such that there is a second non-zero distance (d2) in the longitudinal direction between the stack and a second wall (P2) of the outer casing.

3. An assembled battery according to any preceding claim, wherein a first and a last layer of said stack are formed by a first spacer (ESi) and a last spacer (ESn) respectively.

4. Assembled battery according to the preceding claim, in which the first spacer (ESi) and the last spacer (ESn) each have a mechanical structure reinforced relative to the rest of the spacers.

5. Assembled battery according to the preceding claim, in which the first and last spacers comprise a body in the general shape of a plate having two mainly opposite faces, at least one of the faces having at least one stiffening rib (N) adapted to allow said reinforced mechanical structure of the first and last spacers.

6. An assembled battery according to any preceding claim, wherein the spacers and battery cells each have a generally plate-shaped body extending in a transverse plane substantially orthogonal to the stacking direction.

7. An assembled battery according to any one of the preceding claims, wherein said compression assembly comprises at least one rod (Tb T2, T3, T4) passing through said spacers to allow said movement in the longitudinal direction of the spacers and wherein each deformable element is a cylindrical helical spring arranged around a respective rod among said at least one rod, at one end of said respective rod.

8. An assembled battery according to the preceding claim, wherein said at least one element of said compression assembly comprises four rods (Ti, T2, T3, T4) arranged substantially parallel to the longitudinal direction at the four ends of the spacers in order to distribute a compression force produced by the compression assembly over the stack.

9. An assembled battery according to any preceding claim, wherein said stack comprises a so-called fixed spacer having a fixed position in the longitudinal direction in the outer casing, even during expansion of the battery cells, for example, so that said fixed spacer is located substantially in the middle of the stack.

10. An assembled battery according to any preceding claim, comprising spacers (ET) fixed on either side of the stack, the spacers being adapted to be in contact with an internal surface of a wall of the external casing.

11. An assembled battery according to any preceding claim, wherein each spacer comprises at least one female end piece and / or at least one male end piece and wherein a male end piece of each spacer is capable of fitting and sliding inside a female end piece of an adjacent spacer to allow said movement in the longitudinal direction of the spacers.

12. An assembled battery according to any preceding claim, wherein each spacer comprises at least one trench (T) forming, by cooperating with a battery cell adjacent to said spacer, at least one circulation channel, and wherein the outer casing comprises an inlet (EL) and a

13.

14. outlet (SL) connected to the circulation channels to allow the circulation of a heat transfer liquid between said inlet and said outlet through the circulation channels capable of cooling the battery cells. Assembled battery according to any one of the preceding claims, wherein each battery cell comprises an electrical terminal (CE) and wherein the assembled battery comprises a first electrical connection plate (PCI) arranged within the outer casing, the electrical terminals (CE) being made of metal deformable by said movement in the longitudinal direction of the spacers relative to the outer casing and wherein the first electrical connection plate (PCI) comprises openings each crossed by a respective electrical terminal, said openings being sized to allow movement of said electrical terminal following said movement in the longitudinal direction of the spacers relative to the outer casing. An assembled battery according to any preceding claim, wherein the spacers are made of plastic material, for example a glass fiber reinforced plastic material.

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