FR3066260A1 - DEVICE FOR THERMALLY REGULATING ELECTRIC ENERGY STORAGE CELLS OF CYLINDRICAL TYPE - Google Patents

Abstract

The present invention relates to a device (10) for the thermal regulation of electric energy storage cells (20) of the cylindrical type, the device (10) comprising a heat exchanger delimiting a coolant circulation circuit, said heat exchanger comprising a plurality of heat transfer fluid tubes (11, 12, 111, 112, 113, 114) having corrugations (16). According to the invention, said heat exchanger comprises several stages of tubes (11, 12, 111, 112, 113, 114) intended to be arranged along the height (Z) of said electric energy storage cells (20) of cylindrical type.

Description

Device for thermal regulation of cylindrical type electrical energy storage cells 1. Field of the Invention The invention relates to the field of thermal regulation of batteries.

More specifically, the invention relates to the field of thermal regulation devices for batteries made up of several electrical energy storage cells linked together. The invention applies very particularly to electrical energy storage cells of the cylindrical type. The invention can be applied, for example, to batteries fitted to a motor vehicle, the propulsion of which is supplied in whole or in part by an electric motor, or else a residential building, in the tertiary or industrial sector. 2. Prior art

A battery (“battery-pack” in English) is - in particular in the case of electric or hybrid vehicles - generally composed of electrical energy storage cells, hereinafter called electrical cells, generally cylindrical, which are juxtaposed and connected between them in a protective case.

The thermal regulation of these electrical cells is an important point.

In fact, the temperature of the battery must be regulated, at a temperature of around 20 ° C, in order to ensure the reliability, autonomy, and performance of the vehicle, while optimizing the life of the battery.

In order to regulate the temperature of the battery, it is known to use a thermal regulation device ensuring the heating and cooling functions of the battery.

Such a thermal regulation device comprises in particular a heat exchanger delimiting a circulation circuit of a heat transfer fluid, brought into contact or positioned near the electrical cells of the battery.

According to a first solution, the heat exchanger forms a flat surface called "seat plate" on which the electrical cells are positioned. The disadvantage of this solution lies in the fact that the electrical cells are only cooled through their contact surface with the plate.

This first solution therefore has poor performance in terms of thermal regulation.

According to a second solution, the heat exchanger comprises a seat plate and conductive elements extending perpendicular to the plate and connected to one another (for example by screwing, gluing, brazing, etc.).

The electrical cells are positioned on the plate and are surrounded by the conductive elements.

Thus, the electrical cells are thermally regulated by the heat transfer fluid circulating in the seat plate and, by conduction, by the conductive elements.

Such a solution does not allow optimum cooling of all the electrical cells forming the battery since the cells located in the center of the stack are not in contact with the conductive elements surrounding the electrical cells.

The structure of such a heat exchanger is, moreover, relatively complex.

A third solution uses corrugated tubes, inside which a heat transfer fluid circulates, and whose corrugations closely match the cylindrical external shape of electric cells when the tube is brought into contact with a series of cylindrical electric cells. juxtaposed.

This type of heat exchanger thus offers an increased contact surface with the cylindrical electric cells of the battery.

However, the corrugated tubes are conventionally manufactured by extrusion, and the height of the heat exchange tubes which can be obtained by this manufacturing process is limited. This type of heat exchanger is therefore not suitable for large electrical cells which would require, for optimum efficiency, that the heat exchange tubes cover the entire height of the cells.

There is therefore a need to propose a heat exchanger with corrugated tubes which is perfectly suited to the current shapes and dimensions of cylindrical electric cells of batteries, so as to guarantee an optimized contact surface and heat exchange with each of the cells of the drums. 3. Summary of the invention To this end, the invention proposes a device for thermal regulation of electrical energy storage cells of the cylindrical type, the device comprising a heat exchanger delimiting a circuit for circulation of heat-transfer fluid, said heat exchanger comprising a plurality of heat transfer fluid circulation tubes having corrugations.

According to the invention, said heat exchanger comprises several stages of tubes intended to be arranged along the height of said cylindrical type electrical energy storage cells.

Thus, the corrugated tubes of the heat exchanger are distributed over the height of the electrical cells and meander between them, the corrugations of the tubes being adapted to the shape of the electrical cells and the number of stages of tubes being a function of the height of the electrical cells.

The heat exchanges between the heat transfer fluid circulating in the tubes and the electrical cells can take place over the whole (or almost all) of the height of the electric cells, which allows optimization of the exchange surface and thermal regulation ( including cooling) more efficient electrical cells. The invention allows modular architecture according to the size, number and arrangement of the cylindrical electric cells constituting the battery.

The thermal regulation device according to the invention performs the heating and cooling functions of the electrical cells of the battery.

According to a particular aspect of the invention, said tubes are connected to inlet and outlet manifolds of heat transfer fluid.

The collectors make it possible to distribute the heat transfer fluid inside the tubes and to optimize its circulation within the heat exchanger.

According to a particular aspect of the invention, the height of said tubes is at most 80 mm, preferably at most 60 mm.

According to a particular aspect of the invention, the width of said tubes is at least 10 mm, preferably at least 20 mm.

According to a particular aspect of the invention, the thickness of said tubes is between 2 mm and 4 mm.

According to a particular aspect of the invention, the radius of curvature of the corrugations of said tubes is between 0.5 mm and 500 mm.

The radius of curvature of the corrugations is chosen as a function of the external radius of the electrical cells to be thermally regulated, so that each tube of the heat exchanger best matches the shape of the cells, in order to optimize the heat exchange .

According to a particular aspect of the invention, the spacing between the tubes is at least 2 mm. The spacing is preferably minimal so as to thermally regulate the electrical cells homogeneously over their entire height.

According to a particular aspect of the invention, said heat transfer fluid circulation circuit delimited by said heat exchanger forms a U.

According to a particular aspect of the invention, said heat transfer fluid circulation circuit delimited by said heat exchanger forms an external U communicating with an internal U nested inside the external U.

According to a particular aspect of the invention, the thermal regulation device comprises a thermal interface material, preferably an electrical insulator, between said tubes and said electrical cells. The use of this thermal interface material makes it possible, on the one hand, to absorb the geometric dispersions of the electrical cells, linked for example to their external shape (external radius), to the swelling of the electrical cells during their life phase, and / or a positioning defect), and on the other hand to absorb the geometrical dispersions of the heat exchanger, linked for example to the shape and in particular to the radius of the corrugations, or else to flatness or straightness defects of the heat transfer fluid circulation tubes. The invention also relates to a battery module comprising at least one row of cylindrical type electrical cells and a thermal regulation device as described above, the stages of tubes of said thermal regulation device being arranged along the height of said electrical cells. , each of said electrical cells being in contact with a corresponding undulation of said tubes on a contact angle whose apex is the center of said electrical cell.

According to a particular aspect of the invention, said contact angle is between 0 ° and 180 °, and preferably between 0 ° and 60 °. 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:

FIGS. 1 to 7 represent a thermal regulation device according to the invention in which the device comprises two stages of tubes: FIG. 1 is a perspective view of a thermal regulation device according to a first embodiment, when it is brought into contact with electrical cells; Figure 2 is a sectional view of a tube of the device, according to section A-A of Figure 1; Figure 3 is a top view of the thermal control device of Figure 1, when it is contacted with electrical cells; Figure 4 is a partial top view of the thermal control device of Figure 1, alone; FIG. 5 represents a first circulation circuit of heat transfer fluid with one pass, forming an "I", in the device, the inlet and outlet of the heat transfer fluid being located in a central part of the collectors; Figure 6 a second circulation circuit of heat transfer fluid to a pass, forming an "I" in the device, the inlet and outlet of the heat transfer fluid being located in an upper part of the manifolds; Figure 7 a third heat transfer fluid circulation circuit with two passes, forming a "U" in the device.

FIGS. 8 to 10 represent another thermal regulation device according to the invention in which the device comprises four stages of tubes: FIG. 8 shows a first fluid circulation circuit, with four alternating direction passes, in the device, each pass operating in a tube then in the tube immediately above; FIG. 9 represents a second fluid circulation circuit, with two passes, in a U shape, in the device, each pass operating in two tubes simultaneously; FIG. 10 represents a third fluid circulation circuit, with four passes, in the device, the first two passes forming an external U and the following two an internal U located inside the external U.

FIGS. 11 and 12 illustrate a thermal regulation device according to the invention in which a thermal interface material is interposed between the external surface of the tubes of the device and the electrical cells: FIG. 11 is a perspective view of the device when '' it is in contact with electrical cells; FIG. 12 is a top view of FIG. 11.

Figure 13 is a schematic detail view showing several electrical cells which are positioned on either side of a corrugation of a tube of the heat exchanger. 5. Detailed description 5.1 General principle of the invention The invention therefore proposes to optimize the architecture of the thermal regulation devices of cylindrical electric cells which have for example a circular section (it is then an electric cell taking the shape of a right circular cylinder) or an oval section.

To do this, the thermal regulation device of the invention comprises a heat exchanger which comprises a plurality of corrugated tubes, in which a heat transfer fluid circulates, the tubes being distributed in several stages intended to be arranged along the height of the cells. electric cylindrical type.

In other words, several corrugated tubes are placed one above the other, or stacked, so as to come into contact with all (or almost all) of the height of the electrical cells.

The heat exchanges between each of the electrical cells and the heat transfer fluid circulating in the heat exchanger can thus take place over the entire height of the cells, thus optimizing the thermal regulation, and in particular the cooling, of the electrical cells of the battery. 5.2 Description of several embodiments of the invention

In the various figures, unless otherwise indicated, identical elements have the same reference numbers and have the same technical characteristics and operating modes.

FIG. 1 illustrates a first embodiment of the thermal regulation device of the invention.

The device 10 for thermal regulation comprises a heat exchanger formed by two corrugated tubes 11, 12, arranged one above the other and the ends of which are connected together by collecting elements 13, 14.

The device 10 is shown in the position of use, that is to say the tubes 11, 12 being brought into contact with the external surface of cylindrical electrical cells 20.

More precisely, the tubes 11, 12 undulate or meander between two series of electric cells 20 arranged in parallel and in staggered rows, so that each of the faces of the tubes is in contact with a series of electric cells 20.

Although the thermal regulation device 10 is shown with two tubes 11, 12, the number of tubes can be adapted if necessary as a function of the height of the electrical cells 20.

For example, four tubes may be necessary as illustrated in Figures 8 to 10.

Furthermore, it is also possible to superimpose tubes of different dimensions.

Several rows of these stages of tubes may also be provided for thermally regulating a set of electrical cells 20.

The main dimensions of the device and its elements accepted within the scope of the invention are presented to follow. The heat exchanger has a length X and a total height Y (not taking into account the mouths of the collectors 13, 14) (FIG. 1), while the tubes 11, 12 - taken individually - have a length X, a height L and a thickness H (Figure 2).

As can be seen in FIG. 2, the tubes 11, 12 are multi-channel tubes.

The length X is chosen so as to be adapted to the length of the row of cells 20.

The height L of the tubes can be between 10 mm and 80 mm depending on the heat dissipation needs, and is preferably between 20 mm and 60 mm. The thickness H of the tubes can be between 2 mm and 4 mm, this value being chosen as a function of several parameters such as the type of heat transfer fluid circulated inside the tube, the operating pressures and the pressure drop desired.

When they are superimposed, the two tubes 11, 12 are spaced by an interval W which is, for reasons of feasibility and robustness of the exchanger, greater than 2 mm.

The total height Y of the thermal regulation device 10 then corresponds substantially to the sum of the height L of the tubes and to the interval W, and is therefore a function of the number of tubes used.

When the heat exchanger is brought into contact with the electrical cells 20, the height Y of the thermal regulation device 10 corresponds substantially to the height Z of the electrical cells 20.

As illustrated more precisely in FIG. 4, the tubes 11, 12 have corrugations 16 which are formed so as to conform as much as possible to the external shape of the cylindrical electrical cells 20.

The radius of each corrugation 16 can thus vary from 0.5 to 500 mm depending on various parameters, such as the type of electric cell used, the external radius of the electric cell, the need for heat dissipation and the technical feasibility.

As visible in FIGS. 1 and 3, the two faces of the tubes 11, 12 have corrugations 16, and are thus used to come into contact with the electrical cells 20 and to regulate them thermally (in particular to cool them).

The geometrical characteristics of the tubes (height L, length X, thickness H, radius and frequency of ripple, etc.) can be adapted to the geometry of the electrical cells 20 - and in particular their height, their diameter and their general shape - as well as 'to the number of these electrical cells and their arrangement.

Thus, the thermal regulation device of the invention has a modular character, so that it can be easily adapted to the different needs of automobile manufacturers.

In addition to the advantages already mentioned, this architecture makes it possible to reduce the total weight of the thermal regulation device compared to currently existing solutions.

The collecting elements 13, 14, connecting the ends of the tubes 11, 12, have the function of collecting and distributing the heat transfer fluid in the tubes. The inlet E and the outlet S of the heat transfer fluid may, depending on the space available, be located on the same collecting element 13, 14, as illustrated in FIG. 7, or on opposite collecting elements placed at the ends of the tubes, as illustrated in Figures 5 and 6.

The collectors can be fitted with partitions (not shown).

These partitions may, for example, allow the heat transfer fluid to be directed towards the areas of the heat exchanger in which greater heat exchange with the electrical cells is necessary, and therefore optimize the circulation of the heat transfer fluid.

Figures 5 to 7 thus represent different configurations of refrigerant circulation.

According to a first configuration (FIG. 5), the circulation takes place “at I”, that is to say that the heat transfer fluid enters through a first collecting element 13, passes simultaneously through the two tubes 11, 12 over their entire length, and comes out through a second collecting element 14.

The heat transfer fluid does not undergo any major direction variation, passing through the tubes in a single pass.

According to a second configuration (FIG. 6), the circulation is also “at I”, but the inlet E and the outlet S of the heat transfer fluid are made from the top of the collectors and no longer at their center, as is the case in the configuration illustrated in Figure 5.

Finally, according to a third configuration (FIG. 7), the circulation takes place “in a U”, that is to say that the fluid enters from the top of the first collecting element 13, passes through a first tube 11 over its entire length, is returned by the second collector 14 to the second tube 12 which it also crosses over its entire length, and exits from the bottom of the first collector element 13.

In this case, the second reversal manifold 14 allows the heat transfer fluid to turn around, so that it circulates in opposite directions in the first and second tubes 11, 12 respectively.

Thus, the heat transfer fluid passes through the heat exchanger in two successive passes, in opposite directions.

Figures 8 to 10 illustrate a second embodiment in which the heat exchanger comprises four stages of corrugated tubes, that is to say four tubes 111, 112, 113, 114 positioned one above the other.

This configuration is, for example, suitable for higher electrical cells, and requiring significant heat dissipation.

The four tubes 111, 112, 113, 114 are connected at their respective ends by manifolds 115, 116 ensuring the distribution of the heat transfer fluid within the tubes.

In the three circulation configurations illustrated, the inlet E and the outlet S of the fluid in the heat exchanger takes place within the same manifold 116.

According to a first configuration (FIG. 8), the heat transfer fluid thus enters through a first manifold 116 and passes through its length a first tube 114 situated on an outer edge of the heat exchanger (in the drawings, the fluid passes through the tube intended to come into contact with the base of the electrical cells, but could also go through the tube located at the very top of the electrical cells).

The manifold 115 serves as a return, and allows the heat transfer fluid to make a half-turn in the tube 113 located above the tube 114, which it in turn passes through.

Then, the heat transfer fluid is returned by the collector 116 in the tube 112 located above the tube 113, then, after having passed through it, is returned in the tube 111 located above the tube 112 so as to join the collector 116 where he can come out of.

Thus, the heat transfer fluid passes through the heat exchanger in four successive passes, the heat transfer fluid changing direction of flow in each tube 111, 112, 113, 114.

According to a second configuration (FIG. 9), the heat transfer fluid passes through the exchanger in two passes, circulating simultaneously in the two upper tubes 114, 115 in a first direction, then in the two lower tubes 111, 112 in a second direction opposite to the first sense.

Finally, according to a third configuration (FIG. 10), the heat transfer fluid enters through the first manifold 116 and passes along its length the first tube 114 located on an outside edge of the heat exchanger, at the bottom, then is returned to the tube 111 opposite, located on the other outer edge of the exchanger, at the top, by means of a so-called "by-pass" tube.

After having passed through it, it is returned via the collector 116 in the tube 112 immediately below the tube 111, then via the collector 115 in the tube 113 immediately below the tube 112.

In this configuration, the fluid thus crosses the exchanger in four successive passes, firstly forming an external “U-shaped” circuit during the first two passes, then an internal “U-shaped” circuit located inside the external U, during the next two passes.

Here too, the fluid changes direction of flow as each tube 111, 112, 113, 114. passes. The invention is in no way limited to the examples of circulation configurations illustrated in the figures.

For example, circulation could also, according to this second embodiment of the invention, be done "at I", that is to say in a single pass, the inlet E and the outlet S of the fluid s' operating respectively on one of the two collectors situated at the opposite ends of the corrugated tubes.

In the two embodiments presented, the collectors 13, 14 can be made from metal, plastic, rubber or even a composite material.

The tubes 11, 12 are made from a metal having good thermal conduction properties.

Their general shape is obtained by extrusion, folding, injection, machining, foundry, and the corrugations made by stamping or forming. The assembly between the collectors 13,14 and the tubes 11, 12 can be achieved by brazing, welding, gluing in particular.

The heat transfer fluid, or refrigerant, circulating in the heat exchanger is preferably a liquid (for example ethylene glycol), a gas or even a two-phase fluid.

A thermal regulation device has been described in which the corrugated tubes are in direct (or "dry") contact with the electrical cells.

However, according to a variant, illustrated in Figures 11 and 12, the invention provides that a thermal interface material 30 is interposed between the electrical cells 20 and the tubes 11, 12 of the heat exchanger.

This material is preferably made of a single layer which may possibly have thermal insulation or thermal conduction properties, depending on requirements.

This layer can consist of paint, grease, a thermal "pad", gel, rubber, plastic or even foam.

As visible in FIG. 12, two layers of material 30 respectively cover the exterior surface of the two faces of the tubes 11, 12, so as to come into contact with the two series of electric cells 20 which are positioned on either side of the heat exchanger. The use of this material 30 makes it possible: - on the one hand to absorb the geometric dispersions of the electrical cells, linked for example to their external shape (external radius), to the swelling of the electrical cells during their life phase, to a defect positioning, - on the other hand to absorb the geometrical dispersions of the heat exchanger, linked for example to the shape and in particular to the radius of the corrugations, or to defects in the flatness or straightness of the tubes. The objective is to further increase the contact surface between the heat exchanger and the electrical cells, in order to optimize the efficiency of the resulting heat exchange.

FIG. 13 is a schematic detail view showing several electrical cells 20 which are positioned on either side of a corrugation 16 of a tube of the heat exchanger, and in thermal contact (and possibly mechanical with the corrugation 16).

A contact angle "a" is defined between each of the electrical cells 20 and a corrugation 16 of the tube, the apex of which is the center of the electrical cell (the upper electrical cell in FIG. 13), and the sides are the straight lines passing through the center of the electrical cell 20 and the two extreme points of contact between the exterior surface of the electrical cell 20 and the surface of the corrugation 16.

This contact angle "a" is between 0 ° and 180 °, and preferably between 0 ° and 60 °.

Claims (12)

1. Device (10) for thermal regulation of electrical energy storage cells (20) of cylindrical type, the device (10) comprising a heat exchanger delimiting a circulation circuit of heat-transfer fluid, said heat exchanger comprising a plurality of tubes (11, 12, 111, 112, 113, 114) for circulating coolant having corrugations (16), characterized in that said heat exchanger comprises several stages of tubes (11, 12, 111, 112, 113, 114) intended to be arranged along the height (Z) of said cylindrical type electrical energy storage cells (20). 2. Device (10) for thermal regulation according to claim 1, characterized in that said tubes (11, 12, 111, 112, 113, 114) are connected to inlet manifolds (13, 14, 115, 116) and heat transfer fluid outlet. 3. Device (10) for thermal regulation according to claim 1 or 2, characterized in that the height (L) of said tubes (11, 12, 111, 112, 113, 114) is at most 80 mm, preferably at most 60 mm. 4. Device (10) for thermal regulation according to any one of claims 1 to 3, characterized in that the width (L) of said tubes (11, 12, 111, 112, 113, 114) is at least 10 mm, preferably at least 20 mm. 5. Device (10) for thermal regulation according to any one of claims 1 to 4, characterized in that the thickness (H) of said tubes (11, 12, 111, 112, 113, 114) is between 2 mm and 4 mm. 6. Device (10) for thermal regulation according to any one of claims 1 to 5, characterized in that the radius of curvature of the corrugations (16) of said tubes (11,12, 111, 112,113, 114) is between 0 , 5 mm and 500 mm. 7. Device (10) for thermal regulation according to any one of claims 1 to 6, characterized in that the spacing (W) between the tubes (11, 12, 111, 112, 113, 114) is at least minus 2 mm. 8. Device (10) for thermal regulation according to any one of claims 1 to 7, characterized in that said fluid circulation circuit delimited by said heat exchanger forms a U. 9. Device (10) for thermal regulation according to any one of claims 1 to 8, characterized in that said fluid circulation circuit delimited by said heat exchanger forms an external U communicating with an internal U nested inside the U external. 10. Device (10) for thermal regulation according to any one of claims 1 to 9, characterized in that it comprises a thermal interface material (30), preferably an electrical insulator, between said tubes (11, 12 , 111, 112, 113, 114) and said electrical cells (20). 11. Battery module comprising at least one row of electric cells (20) of cylindrical type and a device (10) for thermal regulation according to one of claims 1 to 10, the stages of tubes (11, 12, 111, 112 , 113, 114) of said thermal regulation device (10) being arranged along the height (Z) of said electrical cells (20), each of said electrical cells (20) being in contact with a corresponding corrugation of said tubes (11, 12 , 111, 112, 113, 114) on a contact angle (a) the apex of which is the center of said electrical cell (20). 12. Battery module according to claim 11, characterized in that said contact angle (a) is between 0 ° and 180 °, and preferably between 0 ° and 60 °.