FR3071959A1 - BOX FOR PROTECTING A BATTERY PACK INCORPORATING CIRCULATING CHANNELS OF A HEAT PUMP FLUID - Google Patents

Abstract

The invention relates to a protective case for at least one electric battery module (M) comprising at least one thermal regulation element (12) of the at least one module (M) made of a thermally conductive material. According to the invention, the protective housing (B) is made of a composite material, at least one wall (1) of said protective housing bearing on its inner surface said at least one thermal regulation element (12), said at least one a thermal regulation element (12) delimiting alone, or in combination with said inner surface (100) of said at least one wall, at least one channel (13) for circulating a heat transfer fluid.

Description

The invention relates to the field of thermal regulation of battery modules, in particular for a motor vehicle the propulsion of which is supplied in whole or in part by an electric motor, located in a protective housing forming, with the battery modules, a pack drums.

More specifically, the invention relates to the structure of such a protective housing.

2. Prior art

In the field of electric and hybrid vehicles, the electrical energy storage cells are linked together so as to create an electric generator of desired voltage and capacity, and positioned in a battery module (called module in the following) .

Several interconnected modules form the vehicle battery.

Generally, these modules are enclosed in a rigid and waterproof protective box (called “casing” in English), made of metal, which protects the modules from the external environment.

The protective housing and the modules form a set generally called a battery pack.

Car manufacturers are now seeking to provide more powerful electric or hybrid vehicles with increased electric range.

To this end, an increasing number of modules are onboard in vehicles.

Thus, the battery pack, generally arranged at the level of the vehicle floor, covers an increasingly substantial surface of the vehicle floor and sometimes even forms the bottom of the body of the latter.

Furthermore, during operation of the vehicle, the battery modules may be subjected to temperature variations which can in some cases cause them to be damaged or even destroyed.

Consequently, the thermal regulation of the modules is essential in order, on the one hand, to keep them in good condition and, on the other hand, to ensure the reliability, autonomy, and performance of the vehicle.

Devices intended to regulate the temperature of the modules are therefore implemented to optimize the operation of the modules.

Such a thermal regulation device is traversed by a heat transfer fluid and performs the heating and / or cooling functions of the modules.

The heat transfer fluid can thus absorb the heat emitted by each module in order to cool it or, if necessary, it can provide it with heat if the temperature of the module is insufficient for its proper functioning.

Two conventional techniques make it possible to manufacture / obtain a thermal regulation device, namely:

a first technique according to which the thermal regulation device is formed of a plurality of tubes each having channels through which a heat-transfer fluid circulates so as to form heat exchange zones, or a second technique according to which the thermal regulation device is formed by two stamped plates delimiting, when assembled, circulation channels for a heat transfer fluid so as to form heat exchange zones.

These thermal regulation devices are generally arranged on one side (lateral, upper or lower) of the modules and extend over surfaces equivalent to the dimensions of the battery pack.

A thermal regulation device is conventionally positioned directly in contact with the modules (that is to say inside the battery pack), or indirectly in contact with the modules (that is to say outside the pack drums).

When the thermal regulation device is placed inside the battery pack, it is generally in contact with the electrical modules and there is therefore a risk of destruction of the modules in the event of leakage of the heat transfer fluid in the internal enclosure of the battery pack. .

Another drawback of this technique lies in the fact that the space allocated for receiving the battery modules within the battery pack is reduced due to the presence of the thermal regulation device and the number of fluid connections.

Thus, the power and the electric range of the vehicle are not maximized.

In addition, protective cases are generally made of metal or aluminum, for example.

Although this type of material ensures good mechanical strength of the housing, it has a relatively large weight which is detrimental in optimizing the performance of the battery of a hybrid or electric vehicle.

3. Summary of the invention

The object of the present invention is to solve these problems of the state of the art and proposes a protective housing for at least one electric battery module comprising at least one thermal regulation element of said at least one module made of a material. thermally conductive.

According to the invention, the protective case is made of a composite material, at least one wall of said protective case carrying on its inner surface said at least one thermal regulation element.

In addition, said at least one thermal regulation element delimits alone, or in combination with said interior surface of said at least one wall, at least one circulation channel for a heat transfer fluid.

The invention thus provides a protective case for battery modules of a hybrid or electric vehicle, which performs two functions, namely a conventional structural function making it possible to protect the modules against shocks, and a new regulation function. thermal modules of the battery arranged in the inner enclosure of the housing.

The protective case, which is made of composite material, has sufficient rigidity and mechanical strength to protect the battery modules housed therein, its weight being optimized compared to the prior art metal cases.

One or more thermal regulation elements, made of a thermally conductive material, are located inside the protective housing, against one or more walls (bottom wall, side walls, etc.) of the protective housing.

These thermal regulation elements comprise or form, with the wall or walls of the protective housing, circulation channels for a heat transfer fluid making it possible to regulate the temperature of the battery modules, the latter being in thermal contact with the thermal regulation elements.

Thus, the housing incorporates, in one or more of these walls, heat exchange zones which make it possible to regulate the temperature of the electric battery modules.

it is therefore no longer necessary to add a thermal regulation device inside or outside the protective box since it is already integrated into one or more walls of the box, on the inside of this latest.

The internal space of the protective housing is thus completely allocated for the reception of battery modules, which allows, for a protective housing of dimensions equal to the prior art, to receive a larger number of battery modules and therefore to maximize the vehicle's range and electrical power.

In addition, fluid connections and the risk of heat transfer fluid leakage are minimized.

According to a particular aspect of the invention, said at least one wall of said protective housing has at least one groove, said at least one groove being closed by said at least one thermal regulation element to delimit said at least one circulation channel.

Thus, at least one wall of the protective housing is preformed so as to provide there one or more parallel grooves intended to be closed by the thermal regulation element (s) in order to delimit the circulation channels of the heat transfer fluid.

The heat transfer fluid circulation channels are therefore integrated into the protective housing.

According to another particular aspect of the invention, said at least one thermal regulation element is in the form of a plate covering and closing said at least one groove.

Thus, the channels are delimited by the implementation of a single wall or plate which comes to close the grooves formed on the inner surface of the wall of the protective housing.

Preferably, the grooves all have the same depth (or height) so that the thermal regulation element, which is a flat sheet, comes into contact with the vertices separating two adjacent grooves and on the flat surfaces of the wall situated on the opposite side. and other of the grooves.

Such a technique is simple to implement and inexpensive.

According to yet another particular aspect of the invention, said at least one thermal regulation element is secured to said at least one wall of the housing by welding or by bonding.

These joining techniques of the thermal regulation element (s) on the wall (s) of the housing are simple to implement and make it possible to ensure good mechanical strength of the assembly.

In addition, the seal between two adjacent circulation channels and between the circulation channels and the interior of the protective housing are also optimal.

According to a particular aspect of the invention, said at least one thermal regulation element is secured to said at least one wall of the protective housing by migration of material from said at least one wall towards said at least one thermal regulation element.

Such a joining technique ensures very strong adhesion between the thermal regulation elements and the wall or walls of the protective housing.

Thus, the mechanical strength of the thermal regulation element on the inner wall of the protective housing is optimal.

According to a particular aspect of the invention, at least one connecting element is molded at the ends of said at least one thermal regulation element, said at least one connecting element being secured to said at least one wall of said protective housing by welding or gluing.

This technique of joining the thermal regulation elements to the interior surface or surfaces of the wall of the housing uses connecting elements which are overmolded onto the thermal regulation elements and then joined, by gluing, to the wall of the protective housing.

More specifically, a thermal regulation element is implemented opposite each groove to close the latter.

Each longitudinal edge of a thermal regulation element comprises a connecting element which makes it possible to secure the thermal regulation element between two edges of a groove.

According to a particular aspect of the invention, said at least one thermal regulation element comprises a plate carrying at least one tube delimiting a circulation channel.

Such a thermal regulation element alone delimits the circulation channels of the heat transfer fluid.

Preferably, the thermal control element is manufactured by extrusion.

According to another particular aspect of the invention, at least one wall of said protective housing has a shape corresponding to that of said at least one thermal regulation element which is obtained by forming against said at least one thermal regulation element.

According to yet another particular aspect of the invention, cavities are formed between the external surface of said at least one thermal regulation element and the internal surface of said at least one wall of the housing, the securing of said at least one thermal regulation element with said at least one wall of the housing being produced by filling said cavities with a resin.

The filling of cavities formed between the thermal regulation element (s) and the interior surface of the grooves of the wall makes it possible, after solidification of the resin, to ensure excellent mechanical strength and therefore optimal securing of the thermal regulation element (s) with the wall or walls of the protective housing.

Preferably, the filling of the cavities is carried out by flow or injection of resin.

According to a particular aspect of the invention, the protective housing, and in particular its walls, is made of plastic composite.

It may be a polymer reinforced with carbon fibers or else glass fibers.

Such a plastic composite ensures good mechanical strength of the protective housing at a low cost.

The invention further provides a battery pack for a hybrid or electric vehicle comprising a protective case as described above, in which is housed at least one electric battery module.

4. Figures

Other characteristics and advantages will appear more clearly on reading the following detailed description of particular embodiments of the invention, given by way of simple illustrative and nonlimiting examples, and of the appended drawings, among which:

Figure 1 is a partial sectional view of a protective housing of a battery pack according to a first embodiment of the invention;

Figure 2 is a partial sectional view of a protective housing of a battery pack according to a second embodiment of the invention;

Figure 3 is a partial sectional view of a protective casing of a battery pack according to a third embodiment of the invention;

Figure 4 is a detail view of the protective housing of Figure 3; Figure 5 is a partial sectional view of a protective housing of a battery pack according to a fourth embodiment of the invention;

FIGS. 6A to 6D detail the steps for obtaining the protective box of FIG. 5.

5. Detailed description of embodiments

Identical elements in the different figures have the same references.

The protective casing of electric battery modules of the invention is made of composite material and carries, on one or more of these interior walls, thermal regulation elements, or heat exchange elements, made of thermally conductive material.

These thermal regulation elements delimit, alone or in combination with the walls of the housing, circulation channels for a heat transfer fluid allowing thermal exchanges with the battery modules arranged in the enclosure of the housing to regulate their temperature.

According to the invention, such a protective housing provides a conventional structural function making it possible to protect the battery modules from the environment outside the housing, and an additional thermal regulation, in particular cooling, function of the modules housed in the housing.

Figure 1 is a partial sectional view of a protective housing B according to a first embodiment of the invention.

Battery modules M are housed in the protective box B and thermally regulated by the latter.

To do this, the protective housing B has at least one double wall 1 (FIG. 1 only illustrates the double bottom wall of the housing) consisting of a first wall, or external wall, 10 and a second wall. , or inner wall 11.

In this example, the outer wall 10 is made of composite and is preformed (by molding, for example) so as to have a section in slots of semi-hexagonal shape (visible in FIG. 1).

Thus, the outer wall 10 has a plurality of grooves 101 (two, in the example illustrated) which extend parallel to one another and whose opening is oriented towards the inside of the housing B.

The inner wall 11, flat, is also made of composite and is intended to be fixed to the outer wall 10.

The inner wall 11 extends opposite the outer wall 10, except at the level of the grooves 101.

The inner 11 and outer 10 walls are joined together by welding.

Other joining techniques can be envisaged such as bonding, for example.

According to the invention, thermal regulation elements 12 are secured to the inner wall 11 so that they extend opposite the grooves 101.

The thermal regulation elements 12 are made of a thermally conductive material, preferably metal.

More preferably, the thermal regulation elements 12 are made of aluminum.

In this example, a thermal regulation element 12 is arranged opposite each of the two grooves 101 and is in the form of a stamped plate.

These thermal regulation elements 12 are intended to close the grooves 101 of the external wall 10 so as to delimit channels 13 for circulation of a heat transfer fluid in the double wall 1 of the protective housing B.

The battery modules M housed in the protective housing B are positioned on the thermal regulation elements 12, in thermal contact with the latter, so as to ensure the heat exchanges between the heat transfer fluid circulating in the channels 13 and the modules M of battery, and to regulate the temperature of the M modules.

In this example, the thermal regulation elements 12 are secured to the interior wall 11 of the housing B by connecting elements 14 made of plastic.

To do this, a first connecting element 14 is molded onto a longitudinal edge of the inner wall 11 and onto a longitudinal edge of a first thermal regulation element 12.

A second connecting element 14 is molded onto the other longitudinal edge of the first thermal regulation element 12 and onto a longitudinal edge of a second thermal regulation element 12.

Finally, a third connecting element 14 is molded onto the other longitudinal edge of the second thermal regulation element 12 and onto a longitudinal edge of the inner wall 11

The connecting elements 14 are then secured by gluing, or welding, to the interior surface 100 of the exterior wall 10.

Thus, the connecting elements 14 allow on the one hand, to secure the thermal regulation elements 12 to each other and to the inner wall 11, and on the other hand to secure the thermal regulation elements 12 to the outer wall 10, in particular on the edges 103 of the grooves 101, as illustrated in FIG. 1.

After the connecting element 14 has been secured to the inner surface 100 of the outer wall 10 of the housing B, the seal between two circulation channels 13, and between the circulation channels 13 and the interior of the protective housing B, is optimally assured.

Consequently, the battery modules M are protected from the risks of leakage of the heat transfer fluid out of the circulation channels 13.

Figure 2 is a partial sectional view of a housing B for protecting battery modules M, according to a second embodiment of the invention.

The wall 1 of the protective housing B is formed by an outer wall 10 made of composite.

This outer wall 10 is preformed so that it has a section of corrugated shape delimiting several parallel grooves 101 (in this case two in this example).

In this second embodiment, the thermal regulation element 12 is in the form of a plate made of a thermally conductive material such as aluminum, for example.

The thermal regulation element 12 is disposed and secured to the interior surface 100 of the exterior wall 10, on the interior side of the housing B, in order to close the grooves 101 to delimit channels 13 for circulation of the heat transfer fluid.

Preferably, the grooves 101 have the same depth / height and the thermal regulation element 12 is in the form of a flat sheet.

The thermal regulation element 12 is easily secured to the inner surface 100 of the outer wall 10, at its flat portions 102 located on either side of the grooves 101 as well as at the vertices 103 separating two grooves 101 consecutive.

In this example, the thermal regulation element 12 is secured to the interior surface 100 of the exterior wall 10 by bonding.

Figure 3 is a partial sectional view of a housing B for protecting battery modules M, according to a third embodiment of the invention.

The wall 1 of the protective housing B is formed by an outer wall 10 of preformed composite having a section in slots of semi-hexagonal shape delimiting several grooves 101 parallel (two in this case in this view).

Similarly to the second embodiment, the thermal regulation element 12 is in the form of a plate made of a thermally conductive material such as aluminum, for example.

The thermal regulation element 12 is disposed and fixed on the internal surface 100 of the external wall 10 so as to close the grooves 101 to delimit channels 13 for circulation of the heat transfer fluid.

To do this, the thermal regulation element 12 is secured to the inner surface 100 of the outer wall 10 at its flat portions 102 located on either side of the grooves 101 as well as at the vertices 103 separating two 101 consecutive grooves.

FIG. 4 is a detailed view of FIG. 3 illustrating the technique for securing the thermal regulation element 12 on the internal surface 100 of the external wall 10.

As can be seen, the thermal regulation element 12 made of aluminum has deformations 121, such as asperities or microgrooves, which are obtained by the application of a surface treatment on the face of the thermal regulation element 12 intended to come into contact with the interior surface 100 of the exterior wall 10.

These deformations 121 are intended to be filled with material from the outer wall 10 made of composite.

To do this, the outer wall 10 is heated and then pressed against the thermal regulation element 12 so that material from the outer wall 10 migrates and penetrates into the deformations 121 to allow the adhesion of the two walls to each other. .

In other words, material from the outer wall 10 mixes with material from the wall of the thermal control element 12 so as to securely bond these walls together.

This joining technique is implemented on the flat portions 102 of the interior surface 100 located on either side of the grooves 101, as well as at the surface of the apex 103 located between two grooves 101.

The three embodiments described above, in relation to FIGS. 1 to 4, describe thermal regulation elements 12 delimiting, in combination with the wall 1 of the protective housing B, channels 13 for circulation of the heat transfer fluid.

FIG. 5 is a partial section view of a housing B for protecting battery modules M, according to a fourth embodiment of the invention, comprising a wall 1, formed by an outer wall 10 made of composite, and an element of thermal regulation 12 made of aluminum obtained by extrusion.

The thermal regulation element 12 comprises a plate 122, extending horizontally in FIG. 5 which carries two tubes 123 of rectangular section extending parallel to one another on one face of the plate 122.

The tubes 123 delimit channels 13 for circulation of a heat transfer fluid of rectangular section.

Thus, in this fourth embodiment, the thermal regulation element 12 alone delimits the channels 13 for circulation of the heat transfer fluid.

Note that the two lower corners of the tubes 123 each have a flange 124 which extends parallel to the plate 122.

FIGS. 6A to 6D illustrate the main stages in the manufacture of the protective housing B of FIG. 5.

First, there is provided a flat outer wall 10 of composite and a thermal regulation element 12 obtained by extrusion of a thermally conductive material, such as aluminum, and having a shape as described above in relation to Figure 5.

Then, the outer wall 10 is heated, then it is deformed, according to a conventional forming process.

More specifically, the outer wall 10 is formed against the thermal regulation element 12 by the application of two opposite forces applied in the direction of the arrows F1 and F2 (visible in FIG. 6A) until it matches the external shapes of the tubes 123 and of the plate 122 of the thermal regulation element 12.

It should be noted that the plate 122 of the thermal regulation element 12 is found in contact with the external wall 10 after forming, as illustrated in 6B.

FIG. 6B also shows that the implementation of the flanges 124 on the tubes 123 cleans, after forming the external wall 10 against the thermal regulation element 12, cavities 125 between the external wall 10 and the thermal regulation element 12.

In order to secure the thermal regulation element 12 and the external wall 10, the cavities 125 are filled by injection or flow of a resin 126 through the latter, as visible in FIG. 6C.

This resin 126, after solidification, provides a good quality connection between the wall 10 and the thermal regulation element 12.

This fourth embodiment, in which a thermal regulation element 12 obtained by extrusion of a metallic material is used, on which a composite wall of the protective housing B is then formed, also makes it possible to increase the rigidity of protective housing B.

Other aspects and variants

The invention thus proposes to integrate the channels 13 for circulation of the heat transfer fluid in one or more horizontal (s) and / or vertical (s) walls of the protective housing B in which the electric battery modules M are housed.

Thus, the housing B allows on the one hand to protect the battery modules M from shocks and on the other hand, to regulate the temperature of the battery modules M housed in the housing B by the use of circulation channels 13 of a heat transfer fluid integrated into one or more of these walls.

The embodiments described above are given by way of simple illustrative and nonlimiting examples.

Although not described, a combination of some of these embodiments between them cannot be excluded.

The figures illustrate only one wall of the housing B provided with circulation channels 13, in this case the bottom wall of the protective housing B.

It is easily understood that such circulation channels 13 can be implemented on one or more of the walls of the housing B.

The channels 13 can be provided in the side walls and / or the cover of the protective housing B.

It should be noted that the battery modules M are in direct thermal contact with the thermal regulation elements 12 in order to optimize the heat exchanges between the heat transfer fluid circulating in the channels 13 and the battery modules M.

In a variant, a thermal interface material can be used between the modules M and each of the thermal regulation elements 12.

It should also be noted that the thermal regulation elements 12 may be in the form of tubes, plates, or any other form offering sufficient flatness to ensure optimal contact with the modules M of electric battery.

The supply of the circulation channels 13 with heat transfer fluid can be done by means of pipes internal or external to the housing B, or else by means of supply channels formed directly in the walls of the protective housing B.

These channels 13 and pipes form part of a thermal regulation loop of the vehicle batteries.

The walls of the protective housing B are made of a composite material, such as a plastic composite, this material having good strength / mechanical strength for optimal weight.

Thus, the walls of the composite protective casing B provide good protection of the battery modules M housed therein against impact (crash).

The composite used to manufacture the walls of the protective housing can be a polymer reinforced with carbon fibers or glass fibers, for example.

The thermal regulation elements 12 are made of a thermally conductive material so as to optimize the heat exchanges between the battery modules M and the heat transfer fluid circulating in the channels 13 integrated into the housing B.

Preferably, the thermal regulation elements 12 are made of metal, and more particularly of aluminum, for reasons of weight, thermal conduction and ease of assembly.

Several techniques have been described for securing the external wall 10 with the thermal regulation elements 12, namely welding, bonding, filling cavities with a resin or else material migration between the external wall and the element. thermal regulation to allow their joining.

Other techniques allowing this joining while guaranteeing a good seal can be implemented without departing from the general principle of the invention.

Furthermore, the shape of the grooves 101 is not limited to a niche or wave shape.

It is of course understood that other forms of grooves 101 can be implemented.

Claims (11)

1. Housing (B) for protecting at least one electric battery module (M) comprising at least one thermal regulation element (12) of said at least one module (M) made of a thermally conductive material, characterized in that the protective housing (B) is made of a composite material, at least one wall (1) of said protective housing (B) bearing on its internal surface (100) said at least one thermal regulation element (12), said at at least one thermal regulation element (12) delimiting alone, or in combination with said interior surface (100) of said at least one wall (1), at least one channel (13) for circulation of a heat transfer fluid. 2. Protective housing (B) according to claim 1, characterized in that said at least one wall (1) of said protective housing (B) has at least one groove (101), said at least one groove (101) being closed by said at least one thermal regulation element (12) to delimit said at least one circulation channel (13). 3. Protective housing (B) according to claim 2, characterized in that said at least one thermal regulation element (12) is in the form of a plate closing said at least one groove (101). 4. Housing (B) protection according to one of claims 1 to 3, characterized in that said at least one thermal regulation element (12) is secured to said at least one wall (1) of the housing (B) by welding or gluing. 5. Housing (B) protection according to one of claims 1 to 3, characterized in that said at least one thermal regulation element (12) is secured to said at least one wall (1) of the housing (B) of protection by material migration from said at least one wall (1) to said at least one thermal regulation element (12). 6. Protective housing (B) according to one of claims 1 to 3, characterized in that at least one connecting element (14) is molded at the ends of said at least one thermal regulation element (12), said at least one connecting element (14) being secured to said at least one wall (1) of said protective housing (B) by welding or by bonding. 7. Protective housing (B) according to claim 1, characterized in that said at least one thermal regulation element (12) comprises a plate (122) carrying at least one tube (123) delimiting a circulation channel (13) . 8. Protective case (B) according to claim 7, characterized in that at least one wall (1) of said protective case (B) has a shape corresponding to that of said at least one thermal regulation element (12) obtained by forming against said at least one thermal regulation element (12). 9. Protective housing (B) according to claim 8, characterized in that cavities (125) are formed between the outer surface of said at least one element 10 thermal regulation and the internal surface (100) of said at least one wall (1) of the housing (B), the joining of said at least one thermal regulation element (12) with said at least one wall (1) of the housing ( B) being produced by filling said cavities (125) with a resin (126). 10. Battery pack for hybrid or electric vehicle including a box (B) of 15 protection according to one of claims 1 to 9, in which is housed at least one module (M) of electric battery.