FR3071958A1 - DEVICE FOR THERMALLY REGULATING A BATTERY PACK - Google Patents

Abstract

The subject of the invention is a device for the thermal regulation of a battery pack (1) for a motor vehicle comprising at least one battery contained in a protective case (10), the thermal regulation device comprising at least one heat exchanger ( 20) with coolant circulation in contact with said at least one battery. According to the invention, at least one inner wall (111) of said housing (10) has at least one elastic element (30) arranged to press said at least one heat exchanger (20) against said at least one battery.

Description

The present invention relates to a thermal regulation device for a motor vehicle battery pack, and more particularly to a thermal regulation device for an electric and / or hybrid vehicle battery, making it possible to guarantee good heat exchange between the battery and an exchanger. thermal.

The thermal regulation of the battery, especially in the field of electric and hybrid vehicles, is an important point.

In fact, the temperature of the battery must remain between 20 ° C and 40 ° C in order to ensure the reliability, autonomy, and performance of the vehicle, while optimizing the life of the battery.

In all-electric and hybrid vehicles, the battery generally comprises several electrical energy storage cells linked together so as to create an electric generator of desired voltage and capacity, and positioned in a battery module (called module in what follows).

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.

In order to regulate the temperature of the battery, it is known to use a thermal regulation device.

The thermal regulation device comprises a heat exchanger positioned directly in contact with the battery at the bottom of the protective housing and traversed by a heat transfer fluid.

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

To ensure good contact between the battery and the heat exchanger, despite the different mounting clearances and the dimensional differences that may occur, the thermal regulation devices of the prior art propose to position a so-called compression spring between the multiplicity of heat exchanger tubes and the bottom of the battery pack protective case.

In fact, the conditions under which the tubes are pressed against the battery cells are decisive in order to be able to obtain reliable and rapidly effective regulation of the temperature of the battery.

The springs push the tubes of the heat exchanger in the direction of the battery cells, which thus guarantees better contact, and therefore optimized heat exchanges, between the tubes of the heat exchanger and the cells which rest thereon.

These springs are, however, relatively bulky and weigh down the battery pack.

Their fixing also requires manipulations.

It is indeed to take into consideration the current constraints in the automotive field which aim to limit the mass, the size and the manufacturing costs of the battery pack.

In the context of the constraints set out above, the invention provides a device for thermal regulation of a battery pack for a motor vehicle comprising at least one battery contained in a protective housing, the thermal regulation device comprising at least one heat exchanger with circulation of heat transfer fluid in contact with said at least one battery.

According to the invention, at least one interior wall of said housing has at least one elastic element arranged to press said at least heat exchanger against said at least one battery.

Such an approach makes it possible to optimize the mass and size of the elastic element or elements, while keeping a homogeneous plating of the heat exchanger against the battery, and the manufacturing costs.

The elastic element or elements forming springs and intended to hold the fluid circulation tubes of the heat exchanger pressed against the cells of the vehicle battery to regulate their temperature are of simple structure.

Such a battery is in particular dedicated to supplying energy to an electric motor providing all or part of the propulsion of the motor vehicle.

In the mounting position, the elastic element or elements are free from compression.

In the operating position, the elastic element or elements are placed under compression and bear by deformation against the underside of the tubes of the heat exchanger or of the battery cells.

According to a particular aspect of the invention, said at least one elastic element is molded onto said at least one interior wall of the housing.

According to a particular aspect of the invention, said at least one elastic element is obtained by deformation of said at least one interior wall of the housing.

The elastic element (s) may be made of material with the interior wall of the housing and flexible with respect thereto.

According to a particular aspect of the invention, said at least one elastic element has a curved cross section.

The elastic element is for example formed of a transversely arcuate metal strip.

According to a particular aspect of the invention, said at least one elastic element is a leaf spring extending from said at least one interior wall and having a free end.

According to a particular aspect of the invention, said at least one elastic element extends over at least one of the interior walls of the housing among the bottom wall, at least one of the side walls or the closure cover of the housing.

According to a particular aspect of the invention, the thermal regulation device comprises several elastic elements extending parallel to said at least one interior wall of said housing.

According to a particular aspect of the invention, said at least one elastic element bears against the heat exchanger or said at least one battery so as to keep the heat exchanger pressed against said at least one battery to regulate its temperature.

According to a particular aspect of the invention, the housing is made of plastic composite.

Such a housing can be manufactured at lower cost, optionally the elastic element or elements advantageously being produced simultaneously with the housing.

According to a particular aspect of the invention, said at least one elastic element is made of plastic, metal or a composite material.

The invention also covers a device for thermal regulation of a battery pack for a motor vehicle comprising at least one battery or battery cell contained in a housing, at least one fluid circulation tube in contact with the battery and at least one spring, the spring being arranged to press the tube against the battery.

Finally, the invention also relates to a battery pack for a motor vehicle, comprising a battery positioned in a housing, comprising a thermal regulation device as defined above.

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

Figure IA is a partial schematic perspective view of a motor vehicle battery pack using a thermal regulation device according to the invention;

Figure IB is a partial cross-sectional view of the battery pack of Figure IA;

FIGS. 2A to 2C are schematic views, in section, of different elastic elements which can be used in a thermal regulation device according to the invention

To avoid overloading the figures and to make it easy to read the description which will be made of the present invention, the common members shown in the different figures are identified with the same reference numbers.

Figure IA is a partial schematic perspective view of a battery pack 1 of a motor vehicle whose propulsion is provided in whole or in part by an electric motor.

The battery pack 1 comprises a housing 10 in which is positioned a battery (not illustrated in FIG. 1A), generally composed of one or more electrical energy storage cells connected together, in parallel or in series, so 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.

The housing 10 comprises a lower part 11 delimiting an interior enclosure 13 and a cover 12 intended for sealing the interior enclosure 13 of the housing 10.

As illustrated in the partial cross-sectional view of FIG. 1B, a heat exchanger 20 with circulation of heat transfer fluid is arranged against a plurality of cells C for storing electrical energy in order to regulate the temperature thereof, in particular cooling them, within a set temperature range.

The heat exchanger 20 comprises a plurality of generally flat tubes 21 through which the heat transfer fluid circulates.

These tubes 21 are multichannel flat tubes which are connected together by a collector 22 making it possible to convey a heat transfer fluid.

The number of tubes 21 of the heat exchanger 20 is equal to the number of electrical energy storage cells C included in the battery.

Elastic elements 30, called spring bars, are arranged at the bottom of the housing 10 of the battery pack 1 in order to keep the tubes 21 of the heat exchanger 20 pressed against a wall of the storage cells C of electrical energy, by optimizing the heat exchange provided between the cells and the tubes 21.

More specifically, the inner wall 111 of the bottom of the housing 10 has several elastic elements 30 forming springs extending parallel over the width of the bottom of the housing 3.

These elastic elements 30 extend perpendicular to the tubes 21 of the heat exchanger 20.

An insulator can be interposed between the elastic elements 30 and the heat exchanger 20. An insulator can thus be provided for each tube 21.

The elastic elements 30 perform the role of compression of each tube 21 against a storage cell C of corresponding electrical energy.

In the rest position, the elastic elements 30 are free from any compression.

Each elastic element 30 has a domed shape to cause its deformation by vertical compaction on itself when it is located between the heat exchanger 20 and the inner wall 111 of the bottom of the housing.

In the operating position, the upper face of each elastic element 30 bears against the lower face of the tubes 21 of the heat exchanger 20, so that the elastic elements 30 are put in compression and flatten, thus pushing the heat exchanger 20 to the cells C for storing electrical energy from the battery.

In FIG. 2A, the elastic element 30 is defined in the interior wall 111 of the housing 10. It is in the form of a curved spring leaf or tab having a free end forming a support surface 301 which is flat and parallel to the inner wall

111.

In FIG. 2B, the elastic element 30 is defined in the interior wall 111 of the housing 10. It is in the form of a spring leaf of domed shape.

In FIG. 2C, the elastic element 30 is in the form of a curved spring leaf which is overmolded on the interior wall 111 of the housing 10. The ends of the elastic element 30 are anchored to the interior wall 111 .

These shapes make it possible to optimize the bearing of the elastic element 30 against the heat exchanger 20 to provide an efficient and homogeneous plating of the tubes 21 against the cells C for storing electrical energy from the battery.

Note that the walls of the housing 10, and in particular the interior wall 111, are made of plastic composite material.

The elastic elements 30 are made of plastic, metal or a composite material (plastic composite, for example).

The thickness of the elastic elements 30 is, for information, between 0.1 mm and 0.4 mm.

The invention thus provides a simple and reliable solution for ensuring thermal contact of a tube of a heat exchanger against a storage cell C of electrical energy of a vehicle battery.

Integrating these elastic elements into an interior wall of the housing 10 makes it possible to optimize the mass of these components (and therefore to minimize the total weight of the battery pack 1) and the space allocated within the housing 10 to electrical cells.

The elastic elements can press a battery cell against a fixed heat exchanger or a heat exchanger against a fixed battery cell.

The elastic elements 30 can be defined on the bottom wall of the housing 10, on an inner side wall of the housing 10 and / or on the upper wall (on the interior face of the cover 12) of the housing 10.

Claims (11)

1. A thermal regulation device for a battery pack (1) for a motor vehicle comprising at least one battery contained in a protective casing (10), the thermal regulation device comprising at least one heat exchanger (20) with circulation of heat transfer fluid in contact with said at least one battery, characterized in that at least one interior wall (111) of said housing (10) has at least one elastic element (30) arranged to press said at least heat exchanger (20) against said at least one battery. 2. Device according to claim 1, characterized in that said at least one elastic element (30) is molded onto said at least one inner wall (111) of the housing (10). 3. Device according to claim 1, characterized in that said at least one elastic element (30) is obtained by deformation of said at least one inner wall (111) of the housing (10). 4. Device according to claim 2 or 3, characterized in that said at least one elastic element (30) has a curved cross section. 5. Device according to claim 3, characterized in that said at least one elastic element (30) is a leaf spring extending from said at least one interior wall (111) and having a free end. 6. Device according to one of claims 1 to 5, characterized in that said at least one elastic element (30) extends over at least interior walls of the housing (10) among the bottom wall, at least one of side walls or the cover (12) for closing the housing (10). 7. Device according to one of claims 1 to 6, characterized in that it comprises several elastic elements (30) extending parallel to said at least one interior wall (111) of said housing (10). 8. Device according to one of claims 1 to 7, characterized in that said at least one elastic element (30) bears against the heat exchanger (20) or said at 5 at least one battery so as to keep the heat exchanger (20) pressed against said at least one battery to regulate its temperature. 9. Device according to one of claims 1 to 8, characterized in that the housing (10) is made of plastic composite. 10. Device according to one of claims 1 to 9, characterized in that said at least one elastic element (30) is plastic, metal or composite material. 11. Battery pack (1) for a motor vehicle, comprising a battery positioned in a protective housing (10), comprising a thermal regulation device according to one of claims 1 to 10.