Heat exchanger for electric battery cells

Abstract

A heat exchanger (1) for cells (4) of electric batteries, characterized in that it comprises:- a casing (2), extending in a longitudinal direction between a front wall of the casing (2d) and a rear wall of the casing (2e), and in a transverse direction between a right wall of the casing (2b) and a left wall of the casing (2c), - a heat transfer fluid inlet (8),- a heat transfer fluid outlet (9),- a cell support for receiving cells (4) inside the casing (2), the cell support (3) comprising longitudinal series (S1, S2, S3, S4, S5) of cell housings,- a fluid distribution zone (7), connected to the fluid inlet (8) and to the fluid outlet (9), and- a main heat exchange zone, supplied with fluid via the fluid distribution zone (7), and in which is produced, for each series (S1, S2, S3, S4, S5) of housing and on at least part of the height of the cells (4),a heat exchange between the heat transfer fluid and the cells (4) arranged in the housings of the series, the housings of each series (S1, S2, S3, S4, S5) being bordered laterally by on one side a zone of longitudinal circulation of fluid in a forward direction towards the rear wall (2e) of the casing (2), called the main forward circulation zone, and by on the other side a zone of longitudinal circulation of fluid in a return direction towards the front wall (2d) of the casing (2), called the main return circulation zone Figure 3,

Description

Title of the invention: Heat exchanger for electric battery cells

[0001] The invention relates to a heat exchanger for battery cells, in particular for cylindrical battery cells. The invention applies particularly to cylindrical battery cells for electric vehicles.

[0002] With the continuous development of electric mobility, the electric vehicle industry and, consequently, electric vehicle batteries, is booming.

[0003] An electric vehicle battery is typically made up of rechargeable lithium-ion cells connected together. Lithium-ion cells are the most popular due to their cost-effectiveness, offering the best compromise between energy storage capacity and price.

[0004] Batteries can come in many shapes and sizes.

[0005] There are three basic types of battery cells used in electric vehicles: cylindrical cells, prismatic cells, and so-called "pouch" cells.

[0006] Cylindrical cells, which are the most used, are, as their name suggests, cylinder-shaped. They are self-contained in a cylindrical casing which gives them resistance to mechanical shocks.

[0007] Due to the long lifespan of this format, cylindrical cells are the most cost-effective and easiest to manufacture. Cylindrical cells can be limited in their power output, however, so electric vehicles with smaller batteries often use prismatic or pouch cells.

[0008] A prismatic cell is a cell whose chemistry is enclosed in a rigid envelope. Its rectangular shape allows multiple units to be efficiently stacked in a battery module. Pouch cells get their name from their shape, which resembles pockets. They are enclosed in a flexible plastic casing, making them very efficient in terms of space utilization. Their fragile casing means that additional protection is usually required to prevent mechanical damage to the cells.

[0010] The performance of an electric vehicle battery is affected by cold and heat. Thus, the performance of a battery can be considered optimal between 20°C and 40°C.

[0011] To regulate the temperature of the battery cells, it is known to use heat exchange devices using a heat transfer fluid.

[0012] Thus, document US 10,020,550 B2 discloses an energy storage device comprising a coolant inlet manifold, a coolant outlet manifold, and heat exchange tubes extending between the coolant inlet manifold and the coolant outlet manifold, so as to exchange heat between the coolant passing through the heat exchange tubes and cylindrical battery cells adjacent to the heat exchange tubes.

[0013] Document CN 211578831 U describes a cooling device comprising a cooling liquid which flows between a front end and a rear end of the device, in channels communicating with each other and surrounding cylindrical battery cells.

[0014] However, these devices do not allow sufficiently efficient and uniform cooling of the battery cells.

[0015] The present invention aims to remedy these drawbacks.

[0016] The invention thus relates to a heat exchanger for electric battery cells.

[0017] The heat exchanger according to the invention comprises: - a casing, extending in a main longitudinal direction between a first wall called the front wall of the casing and a second wall called the rear wall of the casing, and in a transverse direction between a third wall, called the right wall of the casing and a fourth wall, called the left wall of the casing, - a heat transfer fluid inlet conveying a heat transfer fluid into the casing, - a heat transfer fluid outlet discharging the heat transfer fluid from the casing, - a cell support for receiving cells inside the casing, the cell support comprising longitudinal series of cell housings, - a fluid distribution zone arranged inside the casing, connected to the fluid inlet and the fluid outlet, and - a main heat exchange zone, supplied with fluid via the fluid distribution zone, and in which, for each series of housings and over at least part of the height of the cells, a heat exchange is carried out between the heat transfer fluid and the cells arranged in the housings of the series, the housings of said each series being bordered laterally by, on one side, a zone of longitudinal circulation of fluid in a forward direction towards the rear wall of the casing, called the main forward circulation zone, and on the other side, a zone of longitudinal circulation of fluid in a return direction towards the front wall of the casing, called the main return circulation zone.

[0018] Thus, the back-and-forth circulation of the heat transfer fluid on either side of each series of cell housings means that the cells generally see the heat transfer fluid pass through at the same temperature, which ensures uniform and efficient cooling of the cells.

[0019] The fluid inlet and the fluid outlet may be located at the front wall of the housing.

[0020] The main heat exchange zone may comprise main compartments each comprising a main forward circulation zone followed by a main return circulation zone, the main heat exchange zone being delimited at the front by a front wall of the main heat exchange zone and at the rear by the rear wall of the casing.

[0021] Each main compartment may be provided with a fluid inlet opening and a fluid outlet opening, the fluid inlet opening and the fluid outlet opening allowing each main compartment to communicate with the fluid distribution zone, and each main compartment may comprise a main forward circulation zone, from a fluid inlet opening and up to the rear wall of the casing, and a main return circulation zone, from the rear wall of the casing and up to a fluid outlet opening, said main forward circulation zone and said main return circulation zone being bordered laterally by two adjacent series of housings or by a single series of housings and the right or left wall of the casing.

[0022] The fluid distribution zone may comprise an intermediate transverse wall, delimiting a lower part of the fluid distribution zone, into which the fluid is conveyed from the fluid inlet, and an upper part of the fluid distribution zone, through which the fluid is discharged towards the fluid outlet.

[0023] The fluid inlet opening of each main compartment may be located at the lower portion of the fluid distribution area, and the fluid outlet opening of each main compartment may be located at the upper portion of the fluid distribution area.

[0024] The cell housings are advantageously arranged in a staggered pattern.

[0025] Cell housings may include at least one transverse fluid guiding rib disposed on the right side and / or the left side of the housing.

[0026] At least some ribs may include an air vent opening.

[0027] The right wall of the casing and the left wall of the casing are advantageously provided with transverse fluid guide ribs.

[0028] The heat exchanger may further comprise a lower heat exchange zone, located below the main heat exchange zone, the lower heat exchange zone making it possible to ensure heat exchange between the heat transfer fluid and a lower part of the cells.

[0029] The lower heat exchange zone may comprise lower compartments each communicating with a main compartment associated therewith and located above said lower compartment, each lower compartment comprising a longitudinal fluid circulation zone in a forward direction towards the rear wall of the casing, called the lower forward circulation zone, followed by a longitudinal fluid circulation zone in a return direction towards the front wall of the casing, called the lower return circulation zone, a fluid inlet opening made in a bottom wall of the main heat exchange zone allowing the lower forward circulation zone of each lower compartment to communicate with the main forward circulation zone of the main compartment associated therewith,and a fluid outlet opening made in the bottom wall of the main heat exchange zone allowing the lower return circulation zone of each lower compartment to communicate with the main return circulation zone of the main compartment associated with it.

[0030] Preferably, the casing is made of a rigid material and the cell support is made of a flexible material.

[0031] The housing material may comprise polypropylene or polyamide, and the electric cell holder material may comprise a thermoplastic elastomer (TPE) or silicone.

[0032] The heat transfer fluid may be oil, water and / or glycol.

[0033] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which:

[0034] [Fig-1] is a first perspective view of a heat exchanger according to the invention,

[0035] [Fig.2] is a second perspective view of a heat exchanger according to the invention,

[0036] [Fig.3] is a sectional view along the X,Y plane of the heat exchanger,

[0037] [Fig.4] is a schematic view of the exchanger of [Fig.3] indicating the direction of circulation of the heat transfer fluid,

[0038] [Fig.5] is a detailed perspective view of the interior of the heat exchanger, at a lower part of a fluid distribution zone of the exchanger,

[0039] [Fig.6] is a detailed perspective view of the interior of the heat exchanger, at the level of an upper part of a fluid distribution zone of the exchanger,

[0040] [Fig.7] is a top view of the interior of the heat exchanger,

[0041] [Fig.8] is a partial perspective view of the heat exchanger illustrating a lower heat exchange zone of the exchanger,

[0042] [Fig.9] is a sectional view along the X,Y plane of the heat exchanger, at the level of a main heat exchange zone of the exchanger,

[0043] [Fig. 10] is a first sectional view along the X,Y plane of the heat exchanger, at the level of the lower heat exchange zone of the exchanger, and

[0044] [Fig. 11] illustrates an alternative embodiment of the heat exchanger according to the invention.

[0045] As illustrated in Figures 1 to 4, a heat exchanger 1 according to the invention comprises a casing 2 as well as a support 3 for electric battery cells 4 making it possible to receive and maintain the cells 4 inside the casing 2. The cells 4 are typically cylindrical cells.

[0046] The casing 2 has the overall shape of a rectangular parallelepiped. It extends along an X axis (longitudinal), a Y axis (transverse) and a Z axis (vertical).

[0047] The casing 2 comprises a horizontal bottom wall 2a and four vertical walls, including two longitudinal walls, including a first wall 2b, called the right wall, and a second wall 2c, called the left wall, and two transverse walls, including a third wall called the front wall 2d and a fourth wall called the rear wall 2e. The cover of the exchanger 1 is formed by an upper horizontal wall 3a of the support 3.

[0048] The support 3 comprises a plurality of longitudinal series S1, S2, S3, S4, S5 of cell housings 5 ​​(figures 3, 5 and 8). The housings 5 ​​are open at their upper end and are closed, at least partially, at their lower end by a lower stop which makes it possible to support the cells 4. The upper end of the housings 5 ​​is in contact with the upper wall 3a of the support 3.

[0049] The housings 5 ​​are typically cylindrical, so as to receive cylindrical cells. However, other housing shapes can be envisaged, making it possible to receive other types of battery cells, such as prismatic cells or “pouch” type cells.

[0050] The housings 5 ​​are preferably smaller than the cells, which makes it possible to forcefully insert the cells 4 and to accentuate the contact between the cells 4 and the flexible material of the housing 5.

[0051] The cells 4 are inserted by force into the housings 5, so as to ensure permanent contact between the cells 4 and the heat exchange surface. The maintenance and recyclability of the battery are facilitated because the cells 4 are directly accessible via the upper face of the exchanger 1. The cells 4 can thus be extracted individually and replaced.

[0052] Each series SI, S2, S3, S4, S5 extends longitudinally between a so-called front side and a so-called rear side of the exchanger 1. Each series SI, S2, S3, S4, S5 comprises a plurality of housings 5 ​​which are connected to each other by longitudinal junctions 6 ([Fig.6]). Each series SI, S2, S3, S4, S5 ends at its front end and at its rear end by an end junction formed by a vertical longitudinal rib, including a front end junction 6a and a rear end junction 6b ([Fig.3]).

[0053] The heat exchanger 1 comprises a heat transfer fluid distribution zone 7 and a main heat exchange zone, which is an upper heat exchange zone, inside which a heat exchange takes place between the heat transfer fluid and the battery cells 4 over at least part of the height of the cells 4.

[0054] The fluid distribution zone 7 makes it possible to convey the heat transfer fluid from a fluid inlet 8 to the different series located in the main heat exchange zone, then to recover the heat transfer fluid from the main heat exchange zone and to convey it to a fluid outlet 9.

[0055] The fluid distribution zone 7 is delimited at the front by the front transverse wall 2d of the casing 2, at the rear by a front transverse wall 10 of the main heat exchange zone, and laterally by the right longitudinal wall 2b of the casing 2 and by the left longitudinal wall 2c of the casing 2. The main heat exchange zone is itself delimited at the front by the front transverse wall 10, at the rear by the rear wall 2e of the casing 2, and laterally by the right longitudinal wall 2b of the casing 2 located near the first series S1 of cell housings 5 ​​and by the left longitudinal wall 2c of the casing 2, located near the last series S5 of cell housings 5.

[0056] As shown in Figures 5 and 6, the fluid distribution zone 7 further comprises a horizontal intermediate wall 11 delimiting a lower part 7a of the fluid distribution zone 7 and an upper part 7b of the fluid distribution zone 7.

[0057] A heat transfer fluid circulation path will now be described from the fluid inlet 8 to the fluid outlet 9, in the case of cooling of the cells 4 (figures 4 to 7).

[0058] The fluid inlet 8 is constituted by a horizontal pipe projecting from the casing 2. The fluid enters inside the casing 2, at the level of the lower part 7a of the fluid distribution zone 7. The fluid then enters the main heat exchange zone of the exchanger 1 via inlet openings 12 made in the front wall 10 of the heat exchange zone, at the level of the lower part 7a of the fluid distribution zone 7. Each inlet opening 12 allows the heat transfer fluid present in the fluid distribution zone to circulate in a heat exchange compartment Cl, C2, C3.

[0059] In a variant, not shown, it is possible to envisage that the fluid inlet opening of each main compartment is located at the level of the upper part of the fluid distribution zone, and that the fluid outlet opening of each main compartment is located at the level of the lower part of the fluid distribution zone.

[0060] The fluid thus circulates in a first compartment C1, called the first main compartment, towards the rear wall 2e of the casing 2, in a forward longitudinal direction, between the right wall 2b of the casing 2 and the series S1 of cell housings 5. Once it has reached the rear wall 2e of the casing 2, the fluid returns towards the front wall 10 of the main heat exchange zone, in a return direction, circulating between the series S1 and the series S2 of cell housings 5. The circulation of the fluid in the forward direction is represented by the arrow F1, while the circulation of the fluid in the return direction is represented by the arrow F2.

[0061] The fluid then leaves the compartment C1 of the main heat exchange zone through a first outlet opening 13 of the front wall 10 of the main heat exchange zone, the first outlet opening 13 being located at the level of the upper part 7b of the fluid distribution zone 7. Thus, the fluid returns to the fluid distribution zone 7 and then leaves the exchanger 1 through the fluid outlet 9.

[0062] The main heat exchange zone is thus divided into main compartments C1, C2, C3. In each compartment, the heat transfer fluid makes a round trip, that is to say a circulation from the front to the rear of the heat exchange zone, followed by a circulation from the rear to the front of the heat exchange zone. The passage and the delimitation between the forward circulation and the return circulation are made possible by a spacing between the rear end junction 6b of the odd series S1, S3, S5 and the rear wall 2e of the casing 2, the front end junction 6a being connected to the front wall 10 of the main heat exchange zone. For the even series S2, S4, the front end junction 6a is connected to the front wall 10 of the main heat exchange zone and the rear end junction 6b is connected to the rear wall 2e of the casing 2.

[0063] Each main compartment C1, C2, C3 thus comprises a main forward circulation zone and a main return circulation zone, one side of each housing 5 being bordered laterally by a main forward circulation zone and on the other side by a main return circulation zone. Thus, each cell 4 arranged in its housing 5 is in thermal contact with, on one side, the fluid of the main forward circulation zone and on the other side with the fluid of the main return circulation zone.

[0064] In a second heat exchange compartment C2, called the second main compartment, adjacent to the first main compartment C1, and in the same way, the fluid enters the heat exchange zone of the exchanger 1 via a second inlet opening 12 made in the front wall 10 of the heat exchange zone, the second inlet opening 12 being located at the level of the lower part 7a of the fluid distribution zone 7.

[0065] The fluid then circulates in the second main compartment C2, towards the rear transverse wall 2e of the casing, in a forward direction, between the series S2 and the series S3 of cell housings 5. Once it has reached the level of the rear wall 2e of the casing 2, the fluid returns towards the front wall 10 of the heat exchange zone, in a return direction, circulating between the series S3 and the series S4 of cell housings 5.

[0066] The fluid then leaves the compartment C2 of the main heat exchange zone through a second outlet opening 13 of the front wall 10 of the main heat exchange zone, the second outlet opening 13 being located at the level of the upper part 7b of the fluid distribution zone 7. Thus, the fluid returns to the fluid distribution zone and then leaves the exchanger 1 through the fluid outlet 9.

[0067] Finally, in a third and final heat exchange compartment C3, called the third main compartment, adjacent to the second main compartment C2, the fluid enters the main heat exchange zone of the exchanger 1 via a third inlet opening 12 made in the front wall 10 of the main heat exchange zone, the third inlet opening 12 being located at the level of the lower part 7a of the fluid distribution zone 7.

[0068] The fluid then circulates in the third main compartment C3, towards the rear transverse wall 2e of the casing, in a forward direction, between the series S4 and the series S5 of cell housings 5. Once it has reached the level of the rear wall 2e of the casing 2, the fluid returns towards the front wall 10 of the heat exchange zone, in a return direction, circulating between the series S5 and the left wall 2c of the casing 2.

[0069] The fluid then leaves compartment C3 of the main heat exchange zone through a third outlet opening 13 of the front wall 10 of the main heat exchange zone, the third outlet opening 13 being located at the upper part 7b of the fluid distribution zone 7. Thus, the fluid returns to the fluid distribution zone 7 and then leaves the exchanger 1 through the fluid outlet 9.

[0070] In each main compartment C1, C2, C3, the fluid gradually heats up as it comes into thermal contact with the different cells 4. The fluid is cold when it enters the compartment via the inlet opening 12, then it gradually heats up during the forward direction for become lukewarm at the rear wall 2nd of the casing 2, then during the return direction it becomes hot when it comes out of the compartment through the outlet opening 13.

[0071] The cooling is uniform because each cell 4 is in thermal contact with a fluid that is rather cold on the outward direction side and rather hot on the return direction side. All the cells 4 will thus see the fluid pass through at the same temperature overall, and therefore with the same cooling power.

[0072] In order to increase the heat exchange surface between the heat transfer fluid and the cells 4, the cell housings 5 ​​are advantageously arranged in a staggered pattern. By staggered pattern, we mean a repetitive arrangement of the housings, line by line, where each line (i.e. each longitudinal series of housings) is offset by half a housing relative to the line preceding it and the one following it, the latter two being aligned with each other without offset.

[0073] To promote turbulence and further optimize the heat exchange between the heat transfer fluid and the cells 4, each housing 5 of a given series of the support 3 advantageously comprises at least one transverse fluid guide rib 5a, directed towards a junction 6 of an adjacent series ([Fig.7]).

[0074] The ribs 5a make it possible to guide the fluid around the perimeter of the housings 5 ​​and to create turbulence which improves the heat exchange between the fluid and the cells 4.

[0075] Thus, for each of the intermediate series S2 to S4, the housings 5 ​​advantageously each comprise two transverse ribs 5a, namely a rib directed from the left side towards a junction 6 of an adjacent series and a rib directed from the right side towards a junction 6 of the other adjacent series.

[0076] For the end series S1, each housing 5 of this series comprises a single transverse rib 5a directed towards a junction of the series S2, the right wall 2b of the casing 2 being provided with transverse fluid-guiding ribs 2f each directed towards a junction 6 of the series S1 ([Fig.3]). In the same way, each housing of the end series S5 comprises a single transverse rib 5a directed towards a junction of the series S4, the left wall being provided with transverse fluid-guiding ribs 2f each directed towards a junction 6 of the series S5.

[0077] In order to avoid the presence of air gaps between the cell 4 and its housing 5, and to facilitate the insertion of the cells 4 into the housings 5, certain ribs 5a may comprise an opening 5al (a light) over the entire height of the housing 5 ([Fig.7]). The lights 5al thus allow the evacuation of air during the insertion of the cells into the housings 5. They also increase the flexibility of the housing 5, which makes it possible to manage the swelling of the cells under the effect of temperature.

[0078] To further increase the heat exchange surface between the heat transfer fluid and the cells 4, a second heat exchange zone, called the lower heat exchange zone, can be implemented under the main heat exchange zone, so as to ensure heat exchange between the heat transfer fluid and the underside of the cells 4 (FIGS. 8 to 10).

[0079] The lower heat exchange zone is arranged between the bottom wall 2a of the casing 2 and a bottom wall 14 of the main heat exchange zone located at a distance from the bottom wall 2a of the casing 2.

[0080] In a similar manner to the main heat exchange zone, the lower heat exchange zone is provided with lower compartments C'1, C'2, C'3, arranged under the main compartments C1, C2, C3, and in which the heat transfer fluid makes a round trip, that is to say a circulation from the front to the rear of the heat exchange zone, followed by a circulation from the rear to the front of the heat exchange zone.

[0081] Circulation in the lower heat exchange zone is carried out as follows.

[0082] The heat transfer fluid enters the main heat exchange zone of the exchanger 1 via a first inlet opening 12 made in the front wall 10 of the upper heat exchange zone. The fluid then circulates in particular in the first main compartment C1 and then a portion of the fluid descends and enters a first lower compartment C' 1 arranged under the first main compartment C1 via an inlet opening 15 made in a bottom wall 14 of the main heat exchange zone (see [Fig.9]).

[0083] In the same way as for the first main compartment C1, the fluid then circulates in the first lower compartment C' 1, towards the rear transverse wall of the casing 2e, in a forward direction, between the straight wall 2b of the casing 2 and a first longitudinal wall 17, in a lower forward circulation zone. Once it has reached the rear wall 2e of the casing 2, the fluid returns towards the front wall 2d, in a return direction, circulating between the first longitudinal wall 17 and a second longitudinal wall 18, in a lower return circulation zone. The delimitation between the forward circulation and the return circulation is thus ensured using the first longitudinal wall 17 which starts from a front wall 10' of the lower heat exchange zone, said wall 10' being located in the extension of the front wall 10 of the main heat exchange zone.The first longitudinal wall 17 thus extends from the front wall 10' of the lower heat exchange zone and ends at a distance from the rear wall 2e of the casing 2, so as to leave a passage for the fluid for its return circulation.

[0084] After having passed through the lower return circulation zone, the fluid leaves the lower heat exchange zone through an outlet opening 16 made in the bottom wall 14 of the main heat exchange zone. The fluid thus joins the first main compartment C1 in its main return circulation zone and then goes towards the first outlet opening 13 of the front wall 10 of the upper heat exchange zone. As described above, the fluid then returns to the fluid distribution zone 7 and then leaves the exchanger 1 through the fluid outlet 9.

[0085] In the same way, the heat transfer fluid which enters the second main compartment C2 via a second inlet opening 12 made in the front wall 10 of the main heat exchange zone, then circulates in the second main compartment C2 then a part of the fluid descends and enters a second lower compartment C'2 arranged under the first main compartment C1 via an inlet opening 15 made in the bottom wall 14 of the main heat exchange zone (see [Fig.9]).

[0086] As for the second main compartment C2, the fluid then circulates in the second lower compartment C'2, towards the rear transverse wall 2e of the casing 2, in a forward direction, between the second longitudinal wall 18 and a third longitudinal wall 17 which is identical to the first longitudinal wall, in a lower forward circulation zone. Once it has reached the rear wall 2e of the casing 2, the fluid returns towards the front wall 10', in a return direction, circulating between the third longitudinal wall 17 and a fourth longitudinal wall 18 which is identical to the second longitudinal wall, in a lower return circulation zone. The delimitation between the forward circulation and the return circulation is thus ensured using the third longitudinal wall 17 which starts from the front wall 10' of the lower heat exchange zone.The third longitudinal wall 17 thus extends from the front wall 10' of the lower heat exchange zone and ends at a distance from the rear wall 2e of the casing 2, so as to leave a passage for the fluid for its return circulation.

[0087] The fluid then leaves the lower heat exchange zone through an outlet opening 16 made in the bottom wall 14 of the main heat exchange zone. The fluid thus joins the second main compartment C2 in its main return circulation zone and then goes towards the second outlet opening 13 of the front wall 10 of the main heat exchange zone. As described above, the fluid then returns to the fluid distribution zone 7 and then leaves the exchanger 1 through the fluid outlet 9.

[0088] Finally, the heat transfer fluid which enters the third main compartment C3 via a third inlet opening 12 made in the front wall 10 of the zone main heat exchange zone, then circulates in the third main compartment C3 then a part of the fluid descends and enters a third lower compartment C'3 via an inlet opening 15 made in the bottom wall 14 of the main heat exchange zone (see [Fig.9]).

[0089] As for the third main compartment C3, the fluid then circulates in the third lower compartment C'3, towards the rear transverse wall 2e of the casing 2, in a forward direction, between the fourth longitudinal wall 18 and a fifth longitudinal wall 17 which is identical to the second longitudinal wall, in a lower forward circulation zone. Once it has reached the rear wall 2e of the casing 2, the fluid returns towards the front wall 10', in a return direction, circulating between the fifth longitudinal wall 17 and the left wall 2c of the casing 2, in a lower return circulation zone. The delimitation between the forward circulation and the return circulation is thus ensured using the fifth longitudinal wall 17 which starts from the front wall 10' of the lower heat exchange zone.The fifth longitudinal wall 17 thus extends from the front wall of the lower heat exchange zone and ends at a distance from the rear wall 2e of the casing 2, so as to leave a passage for the fluid for its return circulation.

[0090] The fluid then leaves the lower heat exchange zone through an outlet opening 16 made in the bottom wall 14 of the main heat exchange zone. The fluid thus joins the third main compartment C3 in its main return circulation zone and then goes towards the third outlet opening 13 of the front wall 10 of the main heat exchange zone. As described above, the fluid then returns to the fluid distribution zone 7 and then leaves the exchanger 1 through the fluid outlet 9.

[0091] The first longitudinal wall 17, the second longitudinal wall 18, the third longitudinal wall 17, the fourth longitudinal wall 18 and the fifth longitudinal wall 17 serve as lower stops for the cells 5 of the series S1, S2, S3, S4 and S5 respectively.

[0092] As described above, the casing 2 may generally have the shape of a rectangular parallelepiped. Alternatively, as illustrated in [Fig. 1 1], the casing may have a different shape, for example with areas removed, so as to have a geometry adapted to the environment of the battery.

[0093] The casing 2 is advantageously made of a rigid material, as are the front wall 10 of the main heat exchange zone, the front wall 10' of the lower heat exchange zone, the intermediate transverse wall 11 and the bottom wall 14 of the main heat exchange zone. The support 3 is advantageously made of a flexible material.

[0094] The casing 2 and the support 3 can be secured by welding or by gluing.

[0095] The casing can thus be made of polypropylene, in particular loaded with glass fibers. The casing can also be made of polyamide, in particular loaded with glass fibers.

[0096] The support can be made of TPE (Thermoplastic elastomer), in particular EPDM rubber (for ethylene-propylene-diene monomer). The support can also be made of silicone.

[0097] The support is made of flexible material, which makes it possible to manage the swelling of the cells under the effect of temperature or aging of the cells. The support is advantageously a good thermal conductor. For this purpose, it may comprise conductive fillers of carbon and / or graphite. The support preferably has the smallest possible thickness, so as to promote heat exchange with the heat transfer fluid. For example, the thermal conductivity should advantageously be between 2 Wm '.K 1 and 20 Wm *.K '.

[0098] The heat transfer fluid can be a cold fluid or a hot fluid, depending on whether the battery cells are to be cooled or heated. Another element of the vehicle can be used as a cold or hot source. Thus, if the engine is cold, a heat pump or an electrical resistor can, for example, be used. The heat transfer fluid can, in particular, come from the vehicle's hydraulic circuit.

[0099] The heat exchanger can, for example, be used during a cold start of the vehicle or during battery recharging, when it is necessary to heat or cool the batteries.

[0100] It will be possible to advantageously associate with the heat exchanger various elements known per se, such as a temperature sensor associated with a computer making it possible to evaluate whether the cells must be cooled or heated, or even a pump making it possible to actuate the heat transfer fluid according to a predetermined flow rate which is a function, for example, of the temperature detected by the sensor.

[0101] The number of cells, compartments, associated fluid passages and ribs may vary depending on the configuration of the associated battery module.

Claims

1. Claims Heat exchanger (1) for cells (4) of electric batteries, characterized in that it comprises: - a casing (2), extending in a main longitudinal direction between a first wall called the front wall of the casing (2d) and a second wall called the rear wall of the casing (2e), and in a transverse direction between a third wall, called the right wall of the casing (2b) and a fourth wall, called the left wall of the casing (2c), - a heat transfer fluid inlet (8) conveying a heat transfer fluid into the casing (2), - a heat transfer fluid outlet (9) discharging the heat transfer fluid from the casing (2), - a cell support (3) for receiving cells (4) inside the housing (2), the cell support (3) comprising longitudinal series (S1, S2, S3, S4, S5) of cell housings (5), - a fluid distribution zone (7) arranged inside the casing (2), connected to the fluid inlet (8) and to the fluid outlet (9), and - a main heat exchange zone, supplied with fluid via the fluid distribution zone (7), and in which, for each series (S1, S2, S3, S4, S5) of housings (5) and over at least part of the height of the cells (4), a heat exchange is carried out between the heat transfer fluid and the cells (4) arranged in the housings (5) of the series, the housings (5) of each series (S1, S2, S3, S4, S5) being bordered laterally by, on one side, a longitudinal fluid circulation zone in a forward direction towards the rear wall (2e) of the casing (2), called the main forward circulation zone, and on the other side, a longitudinal fluid circulation zone in a return direction towards the front wall (2d) of the casing (2), called the main circulation zone back,the heat exchanger (1) further comprising a lower heat exchange zone, located below the main heat exchange zone, the lower heat exchange zone making it possible to ensure a heat exchange between the heat transfer fluid and a lower part of the cells (4), the lower heat exchange zone comprising lower compartments (C' 1, C'2, C'3) each communicating with a main compartment (Cl, C2, C3) associated therewith and located above said lower compartment (C' 1, C'2, C'3), each lower compartment (C' 1, C'2, C'3) comprising a longitudinal fluid circulation zone in a forward direction towards the rear wall (2e) of the casing (2), called the lower forward circulation zone, followed by a longitudinal fluid circulation zone in a return direction towards the front wall (2d) of the casing (2), called the lower return circulation zone, a fluid inlet opening (15) made in a bottom wall (14) of the main heat exchange zone allowing the lower forward circulation zone of each lower compartment (C' 1, C'2, C'3) to communicate with the main forward circulation zone of the main compartment (Cl, C2, C3) associated therewith,and a fluid outlet opening (16) made in the bottom wall (14) of the main heat exchange zone allowing the lower return circulation zone of each lower compartment (C' 1, C'2, C'3) to communicate with the main return circulation zone of the main compartment (Cl, C2, C3) associated with it.,

2. Heat exchanger (1) according to claim 1, characterized in that the fluid inlet (8) and the fluid outlet (9) are located at the front wall (2d) of the casing (2).

3. Heat exchanger (1) according to claim 1 or 2, characterized in that the main heat exchange zone comprises main compartments (C1, C2, C3) each comprising a main forward circulation zone followed by a main return circulation zone, the main heat exchange zone being delimited at the front by a front wall (10) of the main heat exchange zone and at the rear by the rear wall of the casing (2e).

4. Heat exchanger (1) according to claim 3, characterized in that each main compartment (Cl, C2, C3) is provided with a fluid inlet opening (12) and a fluid outlet opening (13), the fluid inlet opening (12) and the fluid outlet opening (13) allowing each main compartment (Cl, C2, C3) to communicate with the fluid distribution zone (7), and in that each main compartment (Cl, C2, C3) comprises a main forward circulation zone, from a fluid inlet opening (12) and up to the rear wall (2e) of the casing (2), and a main return circulation zone, from the rear wall (2e) of the casing (2), and a main return circulation zone, from the rear wall (2e) of the casing (2). casing (2) and up to a fluid outlet opening (13), said main forward circulation zone and said main return circulation zone each being bordered laterally by two adjacent series of housings (SI, S2; S2, S3; S3, S4; S4, S5) or by a series of housings (SI, S5) and the right or left wall (2b, 2c) of the casing (2).

5. Heat exchanger (1) according to claim 4, characterized in that the fluid distribution zone comprises (7) an intermediate transverse wall (11), delimiting a lower part (7a) of the fluid distribution zone (7), into which the fluid is conveyed from the fluid inlet (8), and an upper part (7b) of the fluid distribution zone (7), through which the fluid is discharged towards the fluid outlet (9).

6. Heat exchanger (1) according to claim 5, characterized in that the fluid inlet opening (12) of each main compartment (Cl, C2, C3) is located at the lower part (7a) of the fluid distribution zone (7), and in that the fluid outlet opening (13) of each main compartment (Cl, C2, C3) is located at the upper part (7b) of the fluid distribution zone (7).

7. Heat exchanger (1) according to one of claims 1 to 6, characterized in that the cell housings (5) are arranged in a staggered pattern.

8. Heat exchanger (1) according to one of claims 1 to 7, characterized in that cell housings (5) comprise at least one transverse fluid guiding rib (5a) arranged on the right side and / or on the left side of the housing (5).

9. Heat exchanger (1) according to claim 8, characterized in that at least some ribs (5a) comprise an air discharge opening (5a 1).

10. Heat exchanger (1) according to one of claims 1 to 9, characterized in that the right wall (2b) of the housing (2) and the left wall (2c) of the housing (2) are provided with transverse ribs (2f) for guiding fluid.

11. Heat exchanger (1) according to one of claims 1 to 10, characterized in that the casing (2) is made of a rigid material and in that the cell support (3) is made of a flexible material.

12. 17 Heat exchanger according to claim 11, characterized in that the material of the casing (2) comprises polypropylene or polyamide, and in that the material of the cell support (3) comprises a thermoplastic elastomer (TPE) or silicone.

13. Heat exchanger (1) according to one of claims 1 to 12, characterized in that the heat transfer fluid is oil, water and / or glycol.

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