Electric battery module comprising electrochemical cells in a housing and a flow of dielectric fluid washing over the edges of the cells

Abstract

The invention relates to a battery module (1) for storing electrical energy, comprising a housing (3) and a plurality of electrochemical cells (2) in the housing, each of the cells having a generally parallelepiped shape with a first dimension L1 along X, a second dimension L2 along Y and a small thickness along Z, each cell having respective edges (21, 22, 23, 24), the module comprising respective inner volumes (41, 42, 43, 44) positioned between the edges of the cells and the respective walls (31, 32, 33, 34) of the housing located opposite one another, the cells being arranged one after the other in the direction Z, in abutment between the fifth and sixth walls of the housing, with a forced flow of dielectric fluid in the inner volumes, preferably with a system of baffles at least in the first, second and fourth volumes, the dielectric fluid cooling the cells by washing over the edges.

Description

DESCRIPTION TITLE OF THE INVENTION: Electric battery module comprising electrochemical cells in a housing and a circulation of dielectric fluid licking the edges of the cells

[0001] The invention relates to electric battery modules, in particular for an electrically powered motor vehicle.

[0002] Such a battery module allows for the storage of electrical energy and for this purpose includes electrochemical cells. It can be used on board a vehicle or in a stationary manner.

[0003] Such a battery module comprises a housing enclosing and protecting the electrochemical cells.

[0004] A system is generally provided to act on the internal temperature of the electrochemical cells, in particular to cool them, without excluding the case where it is necessary to heat them.

[0005] When electrochemical cells are under heavy load, for example during rapid charging or during a high power demand, the cooling system must be efficient enough to prevent the internal temperature of the electrochemical cell from rising too high, thus avoiding the dreaded event known as "thermal runaway".

[0006] To this end, it has already been proposed to use a dielectric fluid in direct contact with the cells to extract calories and evacuate them remotely. However, this type of solution remains perfectible, particularly in view of the need to have good temperature homogeneity in the different cells and to minimize the quantity of dielectric fluid in the liquid fluid circuit.

[0007] This is how the inventors sought to propose a solution to be able to cool the electrochemical cells of a battery module as efficiently as possible while minimizing the quantity of liquid dielectric fluid required in the fluid circuit.

[0008] To this end, a battery module for storing electrical energy is thus proposed here, comprising a housing of generally parallelepiped shape and a plurality of electrochemical cells enclosed in the housing, in which an orthogonal Cartesian reference frame is provided with a first direction, a second direction and a third direction, each of the cells having a generally parallelepiped shape with a first dimension L1 along the first direction, a second dimension L2 along the second direction and a third dimension E1 called thickness along the third direction, said thickness being at least ten times less than the sum of the first and second dimensions, the first and second directions together defining a reference plane XY of the cells, each cell having in the reference plane XY a general rectangular shape with a first side parallel to the first direction,a second side parallel to the second direction, a third side parallel to the first direction and a fourth side parallel to the second direction, the first side coinciding with a first slice (21) of the cell, the second side coinciding with a second slice (22) of the cell, the third side coinciding with a third slice (23) of the cell, the fourth side coinciding with a fourth slice (24) of the cell, the module comprising a first interior volume (41) interposed between the first slices of the cells and a first wall (31) of the housing located opposite, a second interior volume (42) interposed between the second slices of the cells and a second wall (32) of the housing located opposite, a third interior volume (43) interposed between the third slices of the cells and a third wall (33) of the housing located opposite,and a fourth interior volume (44) interposed between the fourth slices of the cells and a fourth wall (34) of the housing located opposite, the cells being arranged one after the other in the direction of the third direction Z, in facial, indirect or indirect support, between the fifth and sixth walls of the housing, characterized in that a forced circulation of dielectric fluid is provided in the first, second, third, fourth interior volume, in contact, slices, and in that at least the first volume is equipped with a baffle system.

[0009] Thanks to these arrangements, the dielectric fluid circulates in the interior volumes in contact with the slices of the electrochemical cells but does not circulate between the main faces (the large faces) of the electrochemical cells. The quantity of liquid mobilized is thus lower. The four slices are effectively licked by the dielectric fluid.

[0010] The good thermal conductivity of the cell is used in the first and second directions, while the thermal conductivity in the thickness direction is lower. The fluid licks the cells in the areas of better evacuation by intrinsic thermal conduction.

[0011] This ensures good thermal regulation, i.e. generally effective cooling when the cells are under high thermal stress, without sometimes excluding warming if the cells are too cold.

[0012] Regarding the cells, each of which has a general parallelepiped shape, it must be understood here that each cell has the shape of a book. In such a shape, there are two main faces and four edges.

[0013] Advantageously, the cells are wedged along the third dimension between the fifth and sixth walls of the housing. In addition, the cells rest on the baffle system provided on the lower wall. The positioning is thus positive, there is no need to suspend the cells and there is no need to hold them laterally.

[0014] Furthermore, in the first interior volume, due to the presence of the baffles, the fluid must necessarily circulate along a predefined imposed path, and the passage section for the dielectric fluid is everywhere approximately the same in contact with the first slices, and therefore the local circulation speed remains homogeneous over the entire path of the dielectric fluid inside the first volume in contact with the first slices.

[0015] Furthermore, advantageously, the thickness of the fluid layer between the slices and the first wall of the housing is substantially constant.

[0016] We note that the dielectric fluid is single-phase here, it remains essentially in the liquid phase.

[0017] The number of cells in the case can be any, for example between 5 and 50.

[0018] According to one aspect, each cell has a first electrical terminal projecting from the second edge towards the outside of the cell, a second terminal projecting from the fourth edge towards the outside of the cell. These terminals make it possible to connect the cells together in series or parallel mode, via elements called bus-bars, the bus-bars are connected to a general collector conductor of the module which makes it possible to connect the module to neighboring modules by at least one positive external terminal and one negative external terminal.

[0019] According to one aspect, a baffle system is further provided at least in the second and fourth interior volumes.

[0020] The presence of electrical terminals is not incompatible with the formation of a baffle system. By imposing a predefined path for the fluid, it is ensured that all areas of the second and fourth sections of the cells are properly swept by the so-called electrical fluid and are properly cooled. As a result, the passage section for the dielectric fluid is almost the same everywhere, and therefore the local circulation speed remains uniform over the entire path of the dielectric fluid.

[0021] According to one aspect, a baffle system is also provided in the third interior volume. Also on the top, the baffle system then imposes a predefined imposed path for the fluid. By imposing a predefined path for the fluid, it is ensured that all areas of the third sections of the cells are properly swept by the so-called electric fluid and are properly cooled.

[0022] According to one aspect, the baffle system comprises walls (51, 52, 53, 54) and passages (56), with a homogeneous and substantially constant passage section over the entire route provided with baffles. In other words, the wall does not run the entire length of the side, it is interrupted at one end to leave room for a passage. But the height of the wall is complete, the wall does not allow any fluid to pass, except on the side of the passage.

[0023] This imposes a flat serpentine path and ensures a substantially constant fluid circulation speed over the entire path equipped with baffles.

[0024] This is found not only in the first interior volume, i.e. at the level of the lower wall of the housing, but also where applicable at the level of the second and fourth interior volumes, as well as in the third interior volume where applicable.

[0025] According to one aspect, the passages are alternated; that is to say that for a pair [low wall + passage], the following pair is arranged symmetrically, i.e. the passage being at the opposite end of the previous one, i.e. in a staggered pattern. This gives a flat serpentine path.

[0026] According to one aspect, the fluid circulates in the first interior volume between two neighboring walls, and circulates therein along the third direction (Z), and the fluid circulates in the second and fourth interior volumes between two neighboring walls along the second direction (Y).

[0027] In one aspect, the walls in the first volume form support struts. These support struts form a wedge in the vertical direction. In a nominal orientation, the support struts support the weight of the electrochemical cells. The first slices are thus placed on the walls / struts.

[0028] According to one aspect, filling blocks (47) are provided on either side of the electrical terminals to have a substantially homogeneous passage section and to limit the quantity of dielectric liquid required.

[0029] According to one aspect, thermal conduction plates are provided interposed between cells and opening into the third volume. The thermal sampling on the slices is thus supplemented by a sampling on the main faces of the cells via the thermal conduction plates.

[0030] In one aspect, the heat conduction plates have an upper portion that extends at a right angle from the main body of the heat conduction plate.

[0031] In one aspect, the upper portion of the heat conduction plates is licked on both sides. In an alternative aspect, the upper portion of the heat conduction plates is licked on only one side.

[0032] In one aspect, a single fluid inlet and a single fluid outlet are provided for the module. This makes it easier to manage the passage between the inside and the outside, this singular point being addressed in a single part, on a single side of the housing.

[0033] Preferably, the inlet and outlet are adjacent. The sealing of the passages is done locally on a small technical part, for example overmolded or with gaskets.

[0034] In one aspect, the walls may be inserted, in part, between two adjacent cells, with one wall being positioned in line with a foam compression sheet sandwiched between two cells.

[0035] The present invention also relates to a protective and containment housing for a battery module, the housing comprising a bottom wall equipped with projections forming a support and baffles, the housing comprising a fluid inlet and a fluid outlet, and at least two electrical connection terminals, the housing being intended to receive a set of electrochemical cells.

[0036] According to one aspect, the second and fourth walls, and where appropriate the third wall, may also be equipped with walls forming baffles.

[0037] According to a complementary aspect, a passage interface for two fluid conduits and for two electrical conductors may be provided, the function of which is to connect the interior of the housing to the exterior of the housing.

[0038] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: [Fig.1] schematically illustrates in perspective an electrochemical cell forming part of the composition of a battery module according to the present invention; [Fig.2] schematically illustrates a section in the XY plane of an exemplary battery module according to the present invention; [Fig.3] schematically illustrates a section in the YZ plane of an exemplary battery module according to the present invention; [Fig.4] schematically illustrates in perspective a set of electrochemical cells; [Fig.5] schematically illustrates in perspective an example of a bottom wall of the housing with the projections forming support and baffle walls; [Fig.6] schematically illustrates in plan view an example of a bottom wall of the housing with the projections forming support and baffle walls; [Fig.7] shows a perspective diagram of an example of a path of fluid in the interior volumes; [Fig.8] shows in plan view an example of fluid path in the four interior volumes; [Fig.9] schematically illustrates a containment housing for a plurality of electrochemical cells; [Fig.10] schematically illustrates a section in the XY plane of an example of a containment and protection box; [Fig.11] illustrates a partial end view in median section in the XZ plane along section line XI-XI in Figure 2; [Fig.12] schematically illustrates a variant with thermal conduction plates arranged between two neighboring cells; [Fig.13] schematically illustrates a section in the YZ plane of an example of a module according to the variant of figure 12; [Fig.14] shows in perspective view an example of a fluid path in the variant of Figure 12; [Fig.15] schematically illustrates another variant embodiment of the containment box.

[0039] In the various figures, the same references designate identical or similar elements. For reasons of clarity of the presentation, certain elements are not necessarily represented to scale.

[0040] The invention relates to a battery module for an electric propulsion / traction motor vehicle, not shown in the figures. The vehicle considered here may be a four-wheeled vehicle of the sedan, coupe, station wagon, pick-up, van, minivan, etc. type.

[0041] Here, the vehicle in question can be 100% electric or can be a hybrid type vehicle, namely the combination of an electric powertrain with an internal combustion engine.

[0042] An electrically powered / tracted vehicle includes at least one electrical energy storage device, otherwise known as a battery. The vehicle in question here includes one or more battery modules. The modules can be connected together in series or parallel configuration, or a mix of both, to obtain a high voltage on the traction battery, for example 400 volts or more.

[0043] In the present document, a battery module 1 comprises a plurality of electrochemical cells 2. The electrochemical cells in question are typically of the lithium-ion type. Other types of cells are however not excluded. The electrochemical cells 2 are contained and protected inside a housing 3.

[0044] It is noted that the battery module 1 presented here can also be used in a stationary configuration, i.e. independently of a motor vehicle.

[0045] Such a battery module allows to manage electrical energy, depending on the usage cycle, one can store / store energy in the module, or draw energy from the module.

[0046] When electrochemical cells are under heavy load, for example during rapid recharging or during a high power demand, it becomes necessary to provide a cooling system.

[0047] The cooling system must be efficient enough to prevent the internal temperature of the electrochemical cell from rising too high, thus avoiding the dreaded event known as "thermal runaway."

[0048] We define an orthogonal Cartesian reference frame with a first direction noted X, a second direction noted Y and a third direction noted Z, represented in most figures. X, Y, Z are perpendicular two by two.

[0049] With reference to figures 1 and 4, each electrochemical cell 2 has a general parallelepiped shape with a first dimension L1 along the first direction X, a second dimension L2 along the second direction Y and a third dimension E1 called thickness along the third direction Z.

[0050] Each cell has the shape of a book, so we have two main faces 25, 26 and four edges 21, 22, 23, 24.

[0051] The thickness E1 is at least ten times less than the sum of the first and second dimensions L1+L2. In one example, the thickness E1 is at least 20 times less than the sum of the first and second dimensions L1+L2

[0052] L1 can be between 20 cm and 50 cm. L2 can be between 10 cm and 30 cm. E1 can be between 5 mm and 15 mm.

[0053] Each cell 2 has in the reference plane XY a general shape of a rectangle, with a first side 11 parallel to the first direction X, a second side 12 parallel to the second direction Y, a third side 13 parallel to the first direction X and a fourth side 14 parallel to the second direction Y.

[0054] The first 11 side coincides with a first slice 21 of the cell, the second side 12 coincides with a second slice 22 of the cell, the third side 13 coincides with a third slice 23 of the cell and the fourth side 14 coincides with a fourth slice 24.

[0055] To complete the geometric description of a cell, said cell comprises two large faces 25, 26 called main faces, identified in figure 1.

[0056] Each cell has a first electrical terminal B1, for example of positive polarity and a second electrical terminal B2, for example of negative polarity. The first electrical terminal B1 projects from the second slice 22 towards the outside of the cell (towards X -). The second electrical terminal B2 projects from the fourth slice 24 towards the outside of the cell (towards X +).

[0057] As illustrated in Figure 4, an assembly is formed with a plurality of cells 2 juxtaposed against each other at the location of their main face and with their edges generally aligned. The two cells at the extreme positions are noted 27, 28.

[0058] As seen in Figure 15, the housing 3 has a generally parallelepiped shape. The housing comprises a lower wall 31 (called the first wall), a front wall 32 (called the second wall), an upper wall 33 (called the third wall), a back wall 34 (called the fourth wall), a side wall 35 (called the fifth wall) and another opposite side wall 36 (called the sixth wall).

[0059] Turning to Figure 2, the module 1 comprises a first interior volume 41 interposed between the first slices 21 of the cells and the first wall 31 of the housing located opposite. The first interior volume 41 is formed by the space left free between the lower slice of the cells and the bottom wall of the housing. The gap left free has a width along Z of between 30 mm and 150 mm, preferably a width of between 50 mm and 80 mm. The gap left free has a height along Y of between 1 mm and 5 mm, preferably between 2 mm and 3 mm.

[0060] As we will see later, this free space will be the site of a circulation of dielectric fluid for cooling the cells.

[0061] Similarly, the module 1 comprises a second interior volume 42 interposed between the second slices 22 of the cells and the second wall 32 of the housing located opposite, a third interior volume 43 interposed between the third slices 23 and the third wall 33 of the housing located opposite, and a fourth interior volume 44 interposed between the fourth slices 24 and the fourth wall 34 of the housing located opposite.

[0062] On the other hand, on the side of the fifth and sixth walls of the housing, there is no free space left for the presence of dielectric liquid. The cells are arranged one after the other; the end cells 27, 28 of the set of cells are pressed against the fifth and sixth walls of the housing. As will be seen later, there may be an auxiliary element inserted ('spacer') between two cells, but it also bears against the main faces of the cells. In other words, the fifth and sixth walls 35, 36 of the housing sandwich the stack of cells in the Z direction.

[0063] In other words, the cells arranged one after the other in the direction of the third direction Z, are in facial support, indirect or indirect, between the fifth and sixth walls (35,36) of the housing.

[0064] As seen in figures, in particular 3, 4, 11 and 13, the module 1 comprises a plurality of electrochemical cells 2 enclosed in the housing.

[0065] The number of cells contained in the housing 3 can be any between 2 and 50. In practice, most often, there are between 10 and 30 cells in the module and even more preferably between 12 and 24 cells.

[0066] Generally speaking, forced circulation of dielectric fluid is provided in the four interior volumes, i.e. the first interior volume 41, the second interior volume 42, the third interior volume 43 and the fourth interior volume 44.

[0067] This is a forced circulation system. The system includes a pump not shown in the figures.

[0068] The dielectric fluid can be 3M™ Novec™ or SF33™ or any other equivalent fluid.

[0069] With reference to Figures 5, 6 and 8B, a baffle system is provided to constrain the circulation of the fluid and the path of the fluid around the cells. For the case of the first interior volume 41, this baffle system comprises walls 51 and passages 56.

[0070] The path thus defined is noted P1. Path P1 has the shape of a flat serpentine.

[0071] In addition, the walls 51 in the first volume 41 act as support spacers. Figure 12 illustrates that the bottom edge of each cell 21 rests on one or more walls 51. The cells here rest on the walls (here four walls, but the number of walls could be greater). In the example illustrated, wedges 57 are provided, here triangular in shape, these wedges serve to hold the walls in place. In another embodiment, the walls 51 can be made from the material of the bottom wall 31.

[0072] Advantageously, the fluid circulation is carried out in a serial mode inside the module. This ensures sweeping / licking of all slice areas with the same circulation speed.

[0073] It is noted that, in the first interior volume 41, the fluid travels in transverse zigzags, because in fact the walls extend in the YZ plane transversely to the general progression of the fluid from one longitudinal end P1a in X to the other opposite longitudinal end P1b. Between the walls 51, the fluid moves mainly along the Z direction. In the figures, we have represented 5 transverse walls 51 and 4 transverse fluid paths but of course the number of walls could be greater or less important, as well as the number of zigzags of the fluid path.

[0074] We also note that the fluid does not circulate on the main faces of the cells.

[0075] The fluid remains in a liquid phase, there are no bubbles.

[0076] The cumulative volume for the four interior volumes thus remains reasonable and the volume of liquid remains modest. In particular in the present invention, the cumulative volume of the 4 volumes represents less than 1% of the volume of the housing. In one embodiment, the total of the 4 volumes may represent less than 0.5% of the volume of the housing.

[0077] In a similar manner to what has been presented for the baffles inside the first interior volume 41, a system of baffles is also provided in the second interior volume 42 between the second slices 22 of the cells and the second wall 32 of the housing, on the front face of the housing.

[0078] More specifically, turning to Figures 7 and 8D, the path P2 goes back and forth between the walls 52 which extend in an XY plane. Between the walls 52, the fluid moves mainly along the Y direction. The path P2 begins at the arrival point P2a from the interior volume 41 and continues to the outlet at the location denoted P2b.

[0079] Between the vertical walls 52, there are electrical terminals B1, not shown in figure 7, at mid-height.

[0080] Optionally, on the side of the electrical terminals, filling blocks 47 (visible in figures 2 and 10) can be provided above and below said terminals, so that the thickness of the fluid layer is almost identical everywhere. The filling blocks 47 extend from the interior surfaces of the second and fourth walls.

[0081] It is noted that the electrical terminals B1 are also licked by the circulation of the dielectric fluid, which contributes to increasing the heat exchange coefficient between the interior of the cell and the dielectric fluid.

[0082] In a similar manner to what has been presented for the baffles inside the first two interior volumes, a baffle system is also provided in the third interior volume 43 between the third slices 23 of the cells and the third wall 33 of the housing.

[0083] As we will see later, the baffle system on the upper part corresponding to the third interior volume is optional.

[0084] Here too, walls and crossbars 53 are provided, and the device is quite similar to that which was presented for the first interior volume. The fluid makes transverse zigzags along the walls 53 extending in a YZ plane. The flat serpentine path P3 is shown flat in Figure 8A.

[0085] In a similar way to what was presented for the baffles inside the other two interior volumes, a system of baffle in the fourth interior volume 44 between the fourth slices 24 of the cells and the third wall 34 of the housing.

[0086] The path P4 on the dorsal face is similar to what was presented for the second interior volume on the front face side of the housing. The flat serpentine path P4 is shown flat in Figure 8C. The path P4 starts at point P4a from the interior volume 43 and continues to the exit at the location marked P4b.

[0087] In Figure 10, a protective and containment box 3 has been shown in section with all the walls discussed above, the walls being attached to the structure of the box. Thus, it is sufficient to insert all the cells inside the box 3 to obtain the complete battery module.

[0088] Advantageously, according to the present invention, a single input IN and a single output OUT are sufficient to connect the interior of the module with the part of the forced circulation fluid circuit outside the module.

[0089] As illustrated in Figure 8, the fluid enters through the inlet IN, it is directed along the upper path P3 (see Figure 8A) into the interior volume 43; at the outlet of path P3 it joins the fourth interior volume 44 and follows the path P4 (see Figure 8C); the fluid is then directed along the lower path P1 (see Figure 8B) into the interior volume 41; finally, the fluid joins the second interior volume 42 and follows the path P2 before exiting through the outlet OUT (see Figure 8D).

[0090] Note that the input connector 73 and the output connector marked 74 for the dielectric fluid are side by side.

[0091] The figures illustrate an electrical connection bridge between cells, denoted 40, as well as a bus bar B3. It should be noted, however, that the polarity of the first and second terminals B1, B2 is not necessarily uniform. Indeed, it may be provided to arrange a certain number of cells in parallel forming a sub-assembly and to arrange several sub-assemblies in series mode. Some cells may be in a head-to-tail configuration from an electrical point of view.

[0092] It should therefore be considered that the electrical connection configurations are simply indicative; they can in reality be any within the framework of the present invention.

[0093] Figures 12, 13 and 14 illustrate a variant in which thermal conduction plates 6, preferably made of aluminum material, are inserted between two adjacent cells, for example every 2 cells.

[0094] Each thermal conduction plate 6 comprises a main body 60 of small thickness and of dimensions substantially equal to the dimensions L1 and L2 of the electrochemical cells. A portion is further provided which projects upwards from the cells to be bathed by the dielectric liquid which circulates therein.

[0095] In the illustrated example, the projecting portion is formed as a right-angled extension 61 and extends in an XZ plane.

[0096] This extension 61 can be bathed on both of its faces as illustrated in figure 13B or only on one or more of its faces as illustrated in figure 13A.

[0097] According to this configuration, in the third interior volume 43, that is to say in the upper portion of the module 1, the flow circulates in parallel, and no longer in series, between the upper portions of the thermal conduction plates.

[0098] This is illustrated in Figure 14 where the P3 path is linear and parallel over the entire upper portion of the cell slices 23.

[0099] Each electrochemical cell 2 comprises an envelope 20 for containing the electrochemical elements including the liquid or gel electrolyte. This envelope 20 is generally made of multi-layer aluminum foil and can be welded.

[0100] As can be seen in Figure 12, one solution is to fold a sheet forming an envelope back on itself and weld it on three sides, the lower side 21 being free of welding. The upper closure of the cells is achieved by a weld 29, as are those of the lateral edges.

[0101] According to a particular aspect, it is provided to insert compression sheets 7 between the main faces of the cells, as illustrated in Figure 11. For example, one compression sheet 7 is inserted every two cells. The compression sheets are made of foam. Each compression sheet 7 has a thickness of a few tenths of a millimeter.

[0102] In addition, also visible in Figure 11, a wedging feature is provided for the walls 52 which are arranged in the extension of a sheet of compression 7. Thus, when the assembly of cells is inserted from top to bottom inside the housing, the free end of the walls and 52 is wedged between two cells of the assembly. This eliminates the cantilever effect of the free end of the cells. This arrangement can also be applied on the opposite side, namely on the fourth interior volume and the walls 54.

[0103] As regards the mechanical configuration of the housing, a hinged cover with axis A3 can be provided as shown in figure 9.

[0104] The length of the box LB1 corresponds to the first dimension L1 of the cells along X; we can have for example LB1 = L1 + 2xDelta, Delta being the space available between the cell slice (excluding the electrical terminal) and the inner surface of the box wall. Similarly, the height of the box H2 corresponds to the second dimension L2 of the cells along Y; we can have for example H2 = L2 + 2xDelta, Delta being the space available between the cell slice and the inner surface of the box wall.

[0105] Regarding the width LB2, this depends on the number K of cells present in the module. Neglecting the thickness of the compression sheets, we would therefore have L3 = K x E1, E1 being the aforementioned thickness of each cell. And we add to L3 the wall thicknesses to obtain LB2. In this direction, there is no free space left on the side of the fifth wall 35 and the sixth wall 36, the sandwiching mentioned above leaves no space available.

[0106] According to another industrial configuration in Figure 15, it is the side walls 35, 36 which are assembled on a frame formed by the other four walls, according to the dotted arrows. This makes it possible to compress the assembly of the cells to generate a prestress conducive to preventing swelling of the cells under thermal stress.

[0107] In addition, two general electrical terminals 72 are provided for the external connection of the module to another module or to a vehicle electrical network.

Claims

CLAIMS 1. Battery module (1) for storing electrical energy, comprising a housing (3) of generally parallelepiped shape and a plurality of electrochemical cells (2) enclosed in the housing, in which an orthogonal Cartesian reference frame is provided with a first direction (X), a second direction (Y) and a third direction (Z), each of the cells having a generally parallelepiped shape with a first dimension (L1) along the first direction, a second dimension (L2) along the second direction and a third dimension (E1) called thickness along the third direction, said thickness being at least ten times less than the sum of the first and second dimensions, the first and second directions together defining a reference plane XY of the cells, each cell having in the reference plane XY a general rectangular shape with a first side (11) parallel to the first direction,a second side (12) parallel to the second direction, a third side (13) parallel to the first direction and a fourth side (14) parallel to the second direction, the first side coinciding with a first slice (21) of the cell, the second side coinciding with a second slice (22), the third side coinciding with a third slice (23) of the cell, the fourth side coinciding with a fourth slice (24), the module comprising a first interior volume (41) interposed between the first slices of the cells and a first wall (31) of the housing located opposite, a second interior volume (42) interposed between the second slices of the cells and a second wall (32) of the housing located opposite, a third interior volume (43) interposed between the third slices of the cells and a third wall (33) of the housing located opposite,and a fourth interior volume (44) interposed between the fourth slices of the cells and a fourth wall (34) of the housing located opposite, the cells being arranged one after the other in the direction of the third direction Z, in facial, indirect or indirect support, between the fifth and sixth walls (35, 36) of the housing, characterized in that a forced circulation of dielectric fluid is provided in, the first, second, third, fourth interior volumes, and that at least the first volume (41) is equipped with a baffle system.

2. Battery module according to claim 1, in which each cell has a first electrical terminal (B1) projecting from the second edge towards the outside of the cell and a second terminal (B2) projecting from the fourth edge towards the outside of the cell.

3. Battery module according to any one of claims 1 to 2, further comprising a baffle system at least in the second and fourth volumes (42, 44).

4. Battery module according to claim 1, in which the baffle system comprises walls (51, 52, 53, 54) and passages (56), with a homogeneous and substantially constant passage section over the entire route provided with baffles.

5. Battery module according to claim 4, wherein the fluid circulates in the first interior volume (41) between two neighboring walls, and circulates along the third direction (Z), and the fluid circulates in the second and fourth interior volumes between two neighboring walls, along the second direction (Y) 6. Battery module according to any one of claims 4 to 5, in which the walls (51) in the first volume (41) form support spacers.

7. Battery module according to any one of claims 1 to 6, in which thermal conduction plates (6) are provided interposed between cells and opening into the third volume (43).

8. Battery module according to any one of claims 1 to 7, wherein a single fluid inlet (IN) and a single fluid outlet (OUT) are provided for the module.

9. Battery module according to claims 3 and 4, in which the walls (52,54) are inserted, in part, between two adjacent cells, a wall being positioned in the extension of a foam compression sheet (7).

10. Containment housing (3) for a plurality of electrochemical cells comprising a bottom wall (31) equipped with projections forming support and baffles, the housing comprising a fluid inlet and a fluid outlet, and two electrical connection terminals.

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