Heat exchange plate for batteries

Abstract

The present invention relates to a heat exchange system, comprising a battery module (2) and a heat exchange plate (1) for performing heat exchange with the battery module (2) by conduction, the plate (1) comprising a base plate (3) and a thermal contact plate (4) fixed to the base plate (3), the base plate (3) comprising a first fixing component (6) for fixing the heat exchange plate (1) on a support, and comprising a second fixing component (7) for fixing the heat exchange plate (1) against the battery module (2), the second fixing component (7) being separate from the first fixing component (6).

Description

Technical Field

[0001] The present invention claims the priority of French application No. 1910397 filed on September 20, 2019, the content (text, drawings and claims) of which is incorporated herein by reference.

[0002] The present invention relates to the field of batteries, and more particularly to the field of batteries for electric drives of hybrid or electric vehicles. Background Art

[0003] Throughout this document, a "battery" is understood to be a combination of at least one battery module, the at least one battery module comprising at least one electrochemical cell. The battery optionally comprises electrical or electronic components to manage the electrical energy of the at least one module. When there are a plurality of modules, the plurality of modules are combined in a tank or a housing and thus form a battery pack, which is usually expressed in English as "pack batteries", the housing usually comprising an assembly interface and connection terminals.

[0004] Furthermore, throughout this document, the term "electrochemical cell" is understood to be a cell of the lithium-ion (or Li-ion) type, the Ni-Mh type or the Ni-Cd or lead type, for example, which generates electric current by chemical reaction.

[0005] In the art, it is known to assemble the heat exchange plates of the battery in the battery container and then to fit the battery module in the container against the cooling plate.

[0006] A cooling plate for such a configuration is known from patent document FR-A1-3003938, comprising a heat exchange plate comprising a base made of a molded plastic material and a contact plate made of a heat-conducting material. The base made of plastic material allows a more varied fixing to the support to which it is fixed, for example by adding specific fixing tabs.

[0007] The disadvantage of this design is that the plates and the modules are fixed independently of each other in the housing, which results in a dispersion of the positioning between the modules and the plates. Moreover, the housing with the assembly interface for assembling the modules and the plates is complicated to manufacture, and even more complicated when the housing is generally a large part for receiving a plurality of modules and a plurality of heat exchange plates. Summary of the invention

[0008] The object of the present invention is to overcome these disadvantages, in particular by optimizing the cooling plate.

[0009] To this end, the present invention aims to provide a heat exchange system, which includes a battery module and a heat exchange plate that exchanges heat with the battery module through conduction, the heat exchange plate including a base plate and a thermal contact plate that contacts the battery module and is fixed to the base plate, the base plate including a first fixing component for fixing the heat exchange plate on a support member, and including a second fixing component for fixing the heat exchange plate against the battery module, the second fixing component being distinct from the first fixing component.

[0010] Thus, the substrate can be preassembled on the battery module, thereby being accurately positioned relative to each other due to the reduced size chain. Moreover, when the substrate is integrated with the first fixing member and the second fixing member, the support for receiving the substrate can be considered to be simplified because it only includes an assembly interface for assembling the substrate and no longer includes an assembly interface for assembling the battery module.

[0011] According to an embodiment of the present invention, the substrate is made of plastic material.

[0012] Thus, compared with a metal substrate such as an aluminum alloy, the substrate can have a greater thickness and thus a stronger shape rigidity without being too heavy. This shape rigidity thus enables a plurality of battery modules to be fixed on the same substrate.

[0013] Moreover, still in comparison with metallic materials, the plastic material is thermally insulating. For example, the base plate is made of a thermally insulating plastic material having a thermal conductivity (λ) of less than 2 W.m-1.K-1 at 20° C. This makes it possible in particular to avoid heat exchange between the base plate and the external environment of the heat exchange system.

[0014] According to an embodiment of the invention, the plastic material comprises a charge.

[0015] It is noted that, by way of example, a plastic material in resin form is filled with glass or carbon fibers, the thermal conductivity of the material thus formed being slightly higher than that of unfilled plastic, being between 0.15 and 2 W.m-1.K-1 at 20° C., depending on whether the fibers are oriented or not and on the direction of heat propagation considered, which makes it possible to increase the rigidity of the substrate and therefore the size of the substrate.

[0016] According to an embodiment of the invention, the first fixing member or the second fixing member comprises a metal insert inserted in the material of the base plate, the metal insert having an aperture shaped for receiving a screw.

[0017] The first fixing means for example comprises a screw and an insert forming a sleeve with a central smooth opening through which the screw passes. The tightening force of the screw is thus borne by the sleeve and not by the base plate, the threaded end of the screw engaging in the threaded hole of the support. This avoids creep of the plastic material.

[0018] The second fixing means comprises, for example, a screw and an insert having a threaded central orifice through which the threaded end of the screw passes, the head of the screw locking the battery module against the heat exchange plate without risk of damaging the threads of the insert (when the insert is metallic).

[0019] According to an embodiment of the present invention, the base plate and the thermal contact plate form a cavity between each other through which the coolant fluid flows.

[0020] According to an embodiment of the present invention, the substrate includes a groove in its thickness through which the coolant fluid flows, the cavity forms a first passage position for the coolant fluid, and the groove forms a second passage position for the coolant fluid.

[0021] These positions or levels are superimposed on each other in the thickness of the heat exchange plate. The path of the coolant fluid in the recess depends on the area to be cooled of the battery module, which path can be, for example, straight in a plurality of parallel pipes, or in the form of serpentines with or without imbrication. The path of the coolant fluid in the recess does not depend on the thermal stresses (because the base plate is made of thermally insulating material), but on the desired (usually minimized) fluid load losses.

[0022] The second passage point can thus transport the coolant fluid isothermally.

[0023] The groove can also increase the shape rigidity of the base plate without adding weight to it.

[0024] According to an embodiment of the present invention, the first location and the second location are fluidly connected in series.

[0025] The second position thus forms a fluid return loop which, being thermally insulated, does not interfere with the efficiency of the heat exchange occurring between the battery module and the heat exchange plate. The coolant fluid in the first position is completely drained from the second position.

[0026] According to an embodiment variant of the invention, the first location and the second location are fluidically connected in parallel.

[0027] The second location thus forms a circuit for transporting a portion of the coolant fluid which, because it is thermally insulated, is not reheated by the fluid in the cavity. The second location opens, for example, into a cavity and / or groove of the second heat exchange plate.

[0028] The present invention is also intended to provide a battery comprising a heat exchange system as defined above and a housing for confining the heat exchange system, the support being the bottom of the housing.

[0029] The housing, for example, comprises a container for receiving the heat exchange system, the container being covered with a cover, thereby forming a confined inner space for protecting the combination of the module and the heat exchange plate from any water splash or impact.

[0030] The invention also aims to provide an assembly method for assembling a battery as defined above, the method successively comprising a first assembly step for assembling the heat exchange plate against the battery module and a second assembly step for assembling the combination on the bottom of the housing.

[0031] The present invention also aims to provide a vehicle, comprising the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other features and advantages of the present invention will become more apparent by reading the following detailed description of the present invention, in which:

[0033] - Figure 1 A heat exchange system consistent with the present invention is shown.

[0034] - Figure 2 The heat exchange system is shown in section at the second fastening component. DETAILED DESCRIPTION

[0035] Figure 1 A heat exchange system according to a non-limiting specific embodiment of the invention is shown. The heat exchange system comprises ten battery modules 2 and a single heat exchange plate 1 that exchanges heat with each of the battery modules 2 by conduction. The battery modules 2 are distributed into groups of eight modules 2 and groups of two modules 2. In a variant not shown, there are two heat plates 2 of different sizes, one of which is in thermal contact with each of the modules in the group of eight modules 2 and the other is in thermal contact with each of the modules in the group of two modules 2. Of course, other configurations are possible, namely with three or more plates, and with modules 2 of any form.

[0036] The modules 2 are preferably parallelepipedal and have faces which are in contact with the heat exchange plates 1. Figure 1 In the example of FIG. 1 , this face is the lower face of the module 2 when the module 2 is in the use position, for example in a land vehicle, but in variants this face may be any face of the module 2 .

[0037] A thermal conductive paste or a thermal conductive pad 12 is usually sandwiched between the contact surface and the heat plate 1 (see Figure 2 ), the thermal paste or pad is beneficial to implement the exchange between the module 2 and the board 1 by conduction by filling the uneven parts or gaps, which are caused by the manufacturing dispersion of the module 2 or the board 1.

[0038] The exchange by conduction between module 2 and plate 1 is a heat flow considered in two possible directions: heat from module 2 towards plate 1 for cooling module 2 ; or conversely, heat from plate 1 towards module 2 for heating module 2 .

[0039] A network of coolant fluid pipes (not shown) connects the plates 1 to one another, the coolant fluid transporting heat towards an exchanger (not shown), for example an air / coolant fluid exchanger.

[0040] In a variation, the coolant fluid is replaced by a gas or a phase-change fluid.

[0041] Figure 2 A heat exchange plate 1 is shown in thermal contact with the face of the module 2. The plate 1 comprises a base plate 3 and a thermal contact plate 4 in contact with the battery module 2, which is fixed to the base plate 3, for example by crimping or gluing or screwing. The base plate 3 comprises a first fixing part 6 for fixing the heat exchange plate 1 on a support (not shown). The base plate 3 comprises a second fixing part 7 for fixing the heat exchange plate 1 against the battery module 2. The second fixing part 7 is separate from the first fixing part 6.

[0042] The base plate 3 is made of a plastic material, for example of injection-molded plastic. In a variant, the plastic material comprises a filler.

[0043] The first fixing means 6 or the second fixing means 7 comprise a metal insert 10, 8 inserted in the material of the base plate 3, the metal insert 10, 8 having an orifice shaped to receive a screw (not shown). In the example shown, the insert 10 of the first fixing means 6 (so-called first insert 10) is a sleeve having a central smooth orifice passed by a first screw, the threaded end of which engages in a threaded hole of the support, each end of the sleeve being flush with the outer surface of the base plate 3 so that the sleeve bears all the tightening forces between the head of the first screw and the support. The insert 8 of the second fixing means 7 (so-called second insert 8) has a threaded central orifice engaged with the threaded end of a second screw passing through a smooth orifice 14 of the module 2, the head of which tightens the battery module 2 against the heat exchange plate 1 without risk of damaging the threads of the second insert 8 (when the second insert is metal).

[0044] The first insert 10 and the second insert 8 are for example overmoulded by the base plate 3. In a variant, these inserts 10, 8 are screwed, glued or pressed into the base plate 3.

[0045] It is noted that the first and second inserts 10, 8 are arranged in the thickness of a rib 13 of the base plate 3, so as to facilitate adhesion between the inserts 10, 8 and the base plate 3. Ideally, this rib 13 is arranged partially or completely along the length of one of the four sides of the base plate 3, ideally on the longest side, so as to further stiffen the base plate 3. In the example shown, only a single first rib 13 is visible, but it is understood that a second rib 13 is arranged on the opposite side of the base plate 3 and parallel to the first rib, which second rib 13 also integrates the first and second fixing parts 6, 7. Other geometries of the ribs 13 and the base plate 3 can be envisaged, in particular when the battery module 2 is not parallelepipedal but, for example, cylindrical or has rupture planes (plans brisés), so as to adapt to the interface of the vehicle structure.

[0046] according to Figure 2 In the embodiment shown above, the base plate 3 and the thermal contact plate 4 form a cavity 5 between each other through which the coolant fluid flows. Moreover, the base plate 3 includes a groove 11 through which the coolant fluid flows in its thickness, the cavity 5 forms a first passage position for the coolant fluid, and the groove 11 forms a second passage position for the coolant fluid.

[0047] The first location and the second location are for example fluidically connected in series, but in a variant the first location and the second location are fluidically connected in parallel.

[0048] These positions or levels are stacked one on top of the other in the thickness of the heat exchange plate 1. The path of the coolant fluid in the cavity 5 depends on the area to be cooled of the battery module 2, and the path 16, 17 can be, for example, straight in a plurality of parallel pipes 16, 17, or in the form of a labyrinth or serpentine tube with or without shingling. As in the general way, Figure 2 These ducts 16 , 17 shown in FIG. 4 are formed, for example, by a web 15 which results from the molding of the base plate 3 and is embodied so as to lie against the thermal contact plate 4 .

[0049] The path of the coolant fluid in the groove 11 is not determined by thermal stresses (since the base plate 3 is made of a thermally insulating material) but by the desired (usually minimized) fluid load losses. Figure 2 The example of shows the path in a similar manner to the same partition 15 , which extends in the groove 11 .

[0050] Note that, advantageously, this web 15 participates in the rigidity of the base plate 3 in the same way as the ribs 13 .

[0051] The serial connection of the two locations is implemented, for example, by fluid communication (not shown) with the end of the heat exchange plate 1 between the two locations. The connection can be internal or external to the heat exchange plate 1 by using pipes in the coolant fluid pipe network. The coolant fluid extends to successively pass through the first location and then the second location, the second location thus forming a fluid return loop that does not interfere with the efficiency of the heat exchange generated between the battery module 2 and the heat exchange plate 1 because it is thermally insulated. The coolant fluid in the first location is completely emptied from the second location.

[0052] For example, a parallel connection is implemented by arranging a coolant fluid inlet in the heat exchange plate 1 (which is shared by the two positions), each position having a coolant fluid outlet separated from each other. The fluid leaving the first position can thus be conducted to the air / coolant fluid exchanger via the coolant fluid pipe network, while the fluid leaving the second position can be conducted to the fluid inlet of another heat exchange plate 1 before being conducted to the air / coolant fluid exchanger in turn.

[0053] The second location thus forms a circuit for conducting a portion of the coolant fluid which, being thermally insulated, is not reheated by the fluid in the cavity 5. The second location leads, for example, via a coolant fluid conduit network into the cavity and / or groove of the second heat exchange plate.

[0054] In a manner not shown, a housing delimits the heat exchange system, the combination thus forming a battery (for example a vehicle traction battery). The support is, for example, the bottom of the housing.

[0055] This casing insulates the module 2 from any contact with splashing water and confines all gas emissions of the module 2 to the interior space of the casing.

[0056] A vehicle, in particular an electric or hybrid vehicle, advantageously comprises such a battery.

[0057] It is noted that an assembly method for assembling such a battery is advantageous and comprises in succession a first assembly step for assembling the heat exchange plate 1 against the battery module 2 and a second assembly step for assembling this combination on the bottom of the housing. This method makes it possible to obtain a combination of module 2 and heat exchange plate 1, preassembled for example at a supplier and independent of its assembly in an assembly line of a vehicle incorporating the housing. This method makes it possible to facilitate the assembly while guaranteeing the assembly quality of the module 2 on the plate 1 in terms of relative positioning and thermal conductivity. The assembly line is also less complex, with less obstruction at the edges of the line and with a reduced footprint.

[0058] The first assembly step for assembling the heat exchange plate 1 against the battery module 2 is performed by an operator or by an automated assembly component, which performs a first screwing sub-step by using a second fixing component 7, which in the example described above includes a second screw for fastening the heat exchange plate 1 against the battery module 2. The second assembly step for assembling the combination on the bottom of the housing is performed by an operator or by an automated assembly component, which performs a second screwing sub-step by using a first fixing component 6, which in the example described above includes a first screw for fastening the heat exchange plate 1 against the bottom of the housing.

Claims

1. A heat exchange system, comprising a battery module (2) and a heat exchange plate (1) for performing heat exchange with the battery module (2) by conduction, the heat exchange plate (1) comprising a base plate (3) and a thermal contact plate (4) in contact with the battery module (2) and fixed to the base plate (3), the base plate (3) comprising a first fixing member (6) for fixing the heat exchange plate (1) on a support member, characterized in that: The base plate (3) includes a second fixing component (7) for fixing the heat exchange plate (1) against the battery module (2), and the second fixing component (7) is separate from the first fixing component (6). The base plate (3) and the thermal contact plate (4) form a concave cavity (5) between each other through which a coolant fluid flows. The base plate (3) includes a groove (11) in its thickness through which the coolant fluid flows. The concave cavity (5) forms a first passage position for the coolant fluid, and the groove (11) forms a second passage position for the coolant fluid. The heat exchange system according to claim 1 , wherein the base plate is made of plastic material.

3. The heat exchange system of claim 2, wherein the plastic material comprises a filler.

4. A heat exchange system according to claim 2 or 3, wherein the first fixing member (6) or the second fixing member (7) comprises a metal insert (10, 8) inserted into the material of the base plate (3), the metal insert (10, 8) having a hole formed for receiving a screw.

5. The heat exchange system of claim 1, the first pass location and the second pass location being fluidly connected in series.

6. The heat exchange system of claim 1, wherein the first and second passage locations are fluidly connected in parallel.

7. A battery comprising the heat exchange system according to any one of the above claims and a housing for confining the heat exchange system, wherein the support member is the bottom of the housing.

8. A method for assembling the battery according to claim 7, characterized in that: The assembly method comprises successively a first assembly step for assembling the heat exchange plate (1) against the battery module (2) and a second assembly step for assembling the combination on the bottom of the housing.

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