FR3107616A1 - ELECTRIC ENERGY STORAGE DEVICE, VEHICLE INCLUDING AN ELECTRIC ENERGY STORAGE DEVICE - Google Patents

Abstract

Electrical energy storage device (1) comprising: - a support (2), - an element (3) for storing electrical energy, - a heat exchange plate (4) by conduction with the electrical energy storage element (3), and positioned between the support (2) and the electrical energy storage element (3), - a stop (5; 8; 11; 12; 13; 14) comprising a first surface (11) in contact against the element (3) and a second surface (12) in contact against the heat exchange plate (4 ), this abutment (5; 8; 11; 12; 13; 14) comprising a third surface (13) in contact against the support (2), the second surface (12) resting on one side of the heat exchange plate (4) which is opposite the support (2).

Description

ELECTRIC ENERGY STORAGE DEVICE, VEHICLE COMPRISING AN ELECTRIC ENERGY STORAGE DEVICE

The present invention relates to a battery, and more particularly to a battery of an electric propulsion vehicle supplying an electric motor machine.

Battery will be understood throughout the text of this document as an assembly comprising at least one battery module containing at least one electrochemical energy storage cell. This battery optionally comprises electrical or electronic means for managing the electrical energy of this at least one module. When there are several modules, they are grouped together in a tray or casing and then form a battery pack, this battery pack being often designated by the English expression "battery pack", this casing generally containing an assembly interface, and connection terminals.

Furthermore, the term electrochemical energy storage cell will be understood throughout the text of this document to mean cells generating current by chemical reaction, for example of the lithium-ion (or Li-ion) type, of the Ni-Mh type, or Ni-Cd or lead.

In this field, it is known to cool or heat a battery element by a plate traversed by a heat transfer fluid. This plate is in contact by thermal conduction with the element through a heat exchange surface. This element is for example a cell or a module of the battery.

This thermal contact between the plate and the element is decisive insofar as it presents a thermal resistance degrading the thermal efficiency of the plate. It is known to minimize this thermal resistance by filling a remaining space between the plate and the element with a paste or a flexible thermal film, thus ensuring continuity of material over the entire heat exchange surface, even in the presence of geometric dispersions of manufacture or assembly between the plate and the element and whatever the state of the surface (roughness) of the element and the plate.

This solution is effective provided that the thickness of the paste or of the thermal film is not too great (the cost and the thermal resistivity increasing with the thickness), nor too weak (which would no longer guarantee contact by conduction over the entire heat exchange surface, and/or would exceed a pressure resistance limit of the module or of the cell), which amounts to controlling the thickness of the space between the element and the plaque.

For example, document DE-A1-102015201294 discloses a battery, one cell of which is cooled by a cooling plate. This plate rests on an internal surface of the bottom of a module, and partitions separating the cells rest on the plate. Each partition includes a transverse protuberance serving as a positioning stop for the cells relative to the plate, in order to control the space between the plate and the cell.

But this architecture has drawbacks:
- the partition resting on the plate risks deforming the plate, depending on the force exerted, and thus influencing the space between the plate and the cell by deformation of the plate, and therefore not controlling the thickness of the space .
- the pressing of the cell on the stop, depending on its intensity, can deform the partition or the stop, and can influence the space between the plate and the cell by moving the cell, and therefore not controlling the thickness of the 'space.
- the partition does not position the plate transversely with respect to the surface of the bottom of the module.
- the plate being resting on the surface of the bottom of a module, an uncontrolled heat exchange takes place between the plate and the bottom of the module.

The object of the invention is to better control the thickness of this space.

To this end, the subject of the invention is an electrical energy storage device comprising:
- a support,
- an electrical energy storage element,
- a heat exchange plate by conduction with the electrical energy storage element, and positioned between the support and the electrical energy storage element,
- an abutment comprising a first surface in contact against the element and a second surface in contact against the heat exchange plate,
this device being such that this abutment comprises a third surface in contact against the support, the second surface resting on a face of the heat exchange plate which faces the support.

Thus this invention makes it possible to position the heat exchange plate with respect to the support without it necessarily being in contact with this support, while positioning this same heat exchange plate with respect to the element without it necessarily being in contact with this element. Thus it is possible to preserve a first controlled space between the plate and the element, and a second controlled space between the plate and the support.

This invention has in particular the advantage of positioning the heat exchange plate independently of any means of clamping or assembling the element on the support: these clamping forces, whatever they may be, will not pass through the heat exchange plate since the abutment bears directly on the support on the one hand, and on the element on the other hand. The heat exchange plate can then not be deformed because it is without mechanical stress. These mechanical stresses, due to this tightening, will pass entirely from the element to the support via the abutment.

According to one embodiment of the invention, the abutment comprises a fourth surface, the thickness of the heat exchange plate being inserted between the second and the fourth surface.

Thus this heat exchange plate is locked in position, and the first and second spaces remain controlled even if, for example, a thermal paste or a compressible film is inserted into the second space with a tendency to push the heat exchange plate against the element.

According to one embodiment of the invention, this electrical energy storage device comprises a clamping means shaped to clamp the electrical energy storage element against the first surface.

According to one embodiment of the invention, the clamping means is further shaped to clamp the third surface against the support.

According to one embodiment of the invention, the clamping means is a screw whose thread engages in the support.

According to one embodiment of the invention, the first surface, the second surface and the third surface are flat, the abutment comprising a bore whose axis is orthogonal to the first, second and third surface, the clamping means being integral of the support and passing through both the hole and the element.

In one embodiment of the invention, the heat exchange plate comprises means for positioning the plate against the abutment in a direction different from the direction in which the plate bears on the second or fourth surface, in particular a direction support orthogonal to the support direction of the plate on the second or fourth surface.

The direction of support will be understood throughout the text of this document as the direction of a reaction force of the abutment against the element, the plate, or the support, this reaction force being the consequence of the contact of the surfaces of the abutment with the element, the plate, or the support, whether by their own mass or the clamping means.

This characteristic makes it possible to position the heat exchange plate in several different directions, so that in addition to the control of the first and second spaces, one controls the positioning of the heat exchange plate in a plane passing through the plate.

This positioning means is for example a notch made on an edge of the heat exchange plate, or even a dimensionally calibrated edge of the heat exchange plate.

According to a variant of the invention, this positioning means is a positioning hole through which the stopper passes.

It will be noted that this hole crosses the plate in its thickness, and that according to the rules of isostatism this hole could be for example circular, ovalized, or rectangular.

According to one embodiment of the invention, the stopper comprises:
- a first spacer comprising the first surface,
- a second spacer comprising the second surface and the third surface,
the first spacer and the second spacer being against each other.

This arrangement has the advantage of allowing assembly of the abutment, the plate and the element along a single stacking axis on the support. For example, when the support is a tray comprising a bottom (the underside) and a peripheral side edge, along the same vertical axis, the second spacer will be successively positioned on the bottom, then the plate on the second spacer, then the first spacer which then caps the heat exchange plate, then the element, the clamping means, without the peripheral side edge being inconvenient. It will also be noted, for example, intermediate steps consisting in applying a thermal paste to the plate and/or to the bottom to fill the first and second spaces.

According to a variant of the invention, the abutment is constituted by the first spacer and the second spacer.

According to a variant of the invention, the second spacer is firmly fixed to the plate. For example by crimping, gluing, welding, riveting. This arrangement makes it possible to have fewer parts to handle during the assembly described above.

The invention also relates to a vehicle comprising a battery, this battery comprising an electrical energy storage device as previously described.

It will be noted that the energy storage element is for example an electrochemical battery cell. The support is then a battery module in which the heat exchanger plate is inserted.

Note, as another example, that the energy storage element is a battery module comprising battery cells. The support is then the battery tray in which each module is assembled, the heat exchange plate being inserted between the module and the bottom of the tray, or between two modules.

Other particularities and advantages will appear on reading the description below of a particular, non-limiting embodiment of the invention, made with reference to the single FIGURE in which:
: Figure 1 shows a sectional diagram of the electrical energy storage device.

FIG. 1 represents an electrical energy storage device 1 according to the invention, comprising:
- a support 2,
- an element 3 for storing electrical energy,
- a heat exchange plate 4 by conduction with the electrical energy storage element 3, and positioned between the support 2 and the electrical energy storage element 3,
- a stop comprising a first surface 11 in contact against the element 3 and a second surface 12 in contact against the heat exchange plate 4.
This stop 5; 8; 11; 12; 13; 14 comprises a third surface 13 in contact against the support 2, the second surface 12 resting on a face of the heat exchange plate 4 which faces the support 2.

The stop 5; 8; 11; 12; 13; 14 comprises a fourth surface 14, the thickness of the heat exchange plate 4 being interposed between the second 12 and the fourth 14 surface.

Advantageously, there will remain a clearance between the plate 4 and the second and fourth surfaces 12, 14, for example a clearance of less than 0.1 mm. This small clearance makes it possible to control the positioning of plate 4 in relation to support 2 and element 3.

This device comprises a clamping means 19 shaped to clamp the electrical energy storage element 3 against the first surface 11.

This clamping means 19 is further shaped to clamp the third surface 13 against the support 2.

The clearance described above also makes it possible not to transmit any clamping force from the clamping means 19 to the plate 4.

The heat exchange plate 4 comprises means for positioning the plate 4 against the stop 5; 8; 11; 12; 13; 14 in a direction different from the bearing direction of the plate on the second 12 or fourth 14 surface, in particular a different bearing direction orthogonal to the bearing direction of the plate on the second 12 or fourth 14 surface.

One possibility of this positioning means is illustrated in FIG. 1 by a positioning hole 7 through which the abutment 5 passes; 8; 11; 12; 13; 14.

In addition, the stop 5; 8; 11; 12; 13; 14 includes:
- a first spacer 5 comprising the first surface 11,
- a second spacer 8 comprising the second surface 12 and the third surface 13,
the first spacer 5 and the second spacer 8 being one against the other.

In the example of Figure 1, the stop 5; 8; 11; 12; 13; 14 is constituted by the first spacer 5 and the second spacer 8.

In a variant not shown, the second spacer 8 is integrally fixed to the plate 4.

This invention applies most particularly to a vehicle comprising a battery, the battery comprising an electrical energy storage device 1 as previously described.

Figure 1 shows the energy storage element 3 as being a battery module comprising battery cells (not shown). Support 2 is then the battery tray in which each module 3 is assembled, heat exchange plate 4 being inserted between module 3 and the bottom of the tray, or between two modules 3.

As a second example, not shown, the energy storage element 3 is for example a battery cell. Support 2 is then a battery module in which heat exchanger plate 4 is inserted.

More specifically, Figure 1 illustrates the clamping means 19 by a screw whose thread is engaged in the support 2. This support 2 is a battery tray 2, and the screw 19 has its thread engaged in the bottom of the tray battery 2, for example in a local reinforcement crosspiece of the bottom. This tray comprises a peripheral edge 20, possibly a partition (not shown) separating the tray into two compartments, battery modules 3 being distributed in the tray, and/or around the partition. The screw 19 includes at its end opposite the thread a screw head 21 whose underside of the head rests on the bottom of a bore of the module 3. But this screw 19 is not obligatory, and can be replaced by a stud, or even a screw or eccentric clamping system.

The first surface 11, the second surface 12 and the third surface 13 are flat and annular. The stop 5; 8; 11; 12; 13; 14 comprises a bore 15a, 15b bis whose axis 6 is orthogonal to the first 11, second 12 and third 13 surface, the screw 19 being integral with the support 2 and passing through both the bore 15a, 15b and the element 3 The stop is constituted by the first spacer 5 comprising a first part of the bore 15b, and by the second spacer 8 comprising a second part of the bore 15a. The first spacer 5 and the second spacer 8 are annular rings, in contact with each other at a junction plane between the second surface 12 and the fourth surface 14 inclusive. More particularly, this junction plane in FIG. 1 coincides with the fourth surface 14, which has the advantage that the second spacer 8 penetrates the positioning hole 7 and thereby centers the plate 4. The first and fourth surfaces 11, 14 are opposite faces of a shoulder of the first spacer 5, the second and third surfaces 12, 13 are opposite faces of a shoulder of the second spacer 8.

It will be noted that it is advantageous for the junction plane to include a complementarity of shape between the first spacer 5 and the second spacer 8, so that they can fit into each other to be held in position between -they before inserting the screw 19.

Note that the hole 15a, 15b is not mandatory. In particular when the clamping means 19 is for example a clamping system, the first spacer 5 and the second spacer 8 can be simple wedges. The clamping system comprises for example a clamp resting on the one hand on the tray, on the other hand on the module 3, and a screw passing through the clamp between its two ends and being screwed into the bottom, the peripheral edge, or tray 2 partition.

The heat exchange plate 4 comprises a base plate 18 on the side of the support 2, and a thermal contact plate 17 on the side of the module 3, for example but not necessarily made of stamped sheet metal, and forming a cavity between them in which circulates a heat transfer fluid. On the periphery of this cavity, the base plate 18 and the thermal contact plate 17 are assembled in a sealed manner to one another by known processes such as a process of gluing, welding, riveting, thus forming an edge of the plate 4 heat exchange whose controlled thickness is equal to the thickness of the base plate 18 plus the thermal contact plate 17. It is in this edge that the positioning hole 7 is located, or other means of positioning as a replacement or in addition, such as a notch made on this edge of the heat exchange plate, the stop 5; 8; 11; 12; 13; 14 and more particularly the second spacer 8, being housed in this notch.

Thanks to stop 5; 8; 11; 12; 13; 14, the invention preserves a first space 9 between the module 3 and the thermal contact plate 17, and a second space 10 between the support 2 and the base plate 18, these spaces 9, 10 having a perfectly controlled thickness. It is then possible to fill these spaces 9, 10 with thermally insulating or thermally conductive materials, that is to say of different thermal conductivity. For example, the second space 10 will be filled with a thermally insulating material making it possible to avoid thermal losses through the bottom of the tray 2, while the first space will be filled with a thermally conductive material (therefore more conductive than for the second space 10 ) to facilitate the exchange of heat between the plate 4 and the module 3. These materials are known to those skilled in the art, but the invention will have a particular advantage in using materials in the form of paste or hardening malleable mixture over time, for example resins mixed with a catalyst (generally designated by the English term "liquid gap filler") or hardening in contact with air or plate 4, which allow less effort to be assembled than materials that need to be compressed due to their elasticity (often referred to by the English term “thermal pad”).

Finally, FIG. 1 shows the first spacer 5 comprising a fifth surface 11B, corresponding to the end of the first spacer 5 opposite the junction plane and opposite the module 3, this fifth surface 11B being distinct from the first surface 11. If one perfectly masters the geometric dispersions of manufacture of the module 3, this fifth surface 11B can replace the first surface 11. But this fifth surface 11B, being farther from the first space 9 than the first surface 11, it will involve a dimension chain less favorable to controlling the thickness of the first space 9, in particular the link of the dimension chain concerning module 3 will be more dispersive. For this reason, this fifth surface 11B is not in contact with the module 3 when the clamping means 19 does not apply a clamping force, but has a sufficiently small clearance (for example from 0.05 to 0. 1mm) so that, after application of a clamping force by the clamping means 19, the module 3 deforms slightly and bears on this fifth surface 11B. In this case, even in the event of excessive clamping force, the support of the module 3 on the first surface 11 will remain controlled, and the module will not deform at the level of the support of the first surface 11, and the thickness of the first space 9 remains under control.

Claims (10)

Electrical energy storage device (1) comprising:
- a support (2),
- an element (3) for storing electrical energy,
- a heat exchange plate (4) by conduction with the electrical energy storage element (3), and positioned between the support (2) and the electrical energy storage element (3),
- a stop (5; 8; 11; 12; 13; 14) comprising a first surface (11) in contact against the element (3) and a second surface (12) in contact against the heat exchange plate (4 ),
characterized in that this abutment (5; 8; 11; 12; 13; 14) comprises a third surface (13) in contact against the support (2), the second surface (12) resting on one face of the plate heat exchanger (4) which faces the support (2). Electrical energy storage device (1) according to Claim 1, characterized in that the abutment comprises a fourth surface (14), the thickness of the heat exchange plate (4) being interposed between the second (12) and the fourth (14) surface. Electrical energy storage device (1) according to one of the preceding claims, characterized in that it comprises clamping means (19) shaped to clamp the electrical energy storage element (3) against the first area (11). Electrical energy storage device (1) according to Claim 3, characterized in that the clamping means (19) is further shaped to clamp the third surface (13) against the support (2). Electrical energy storage device (1) according to one of the preceding claims, characterized in that the heat exchange plate (4) comprises means for positioning the plate (4) against the stop (5; 8; 11 ; 12; 13; 14) in a direction different from the bearing direction of the plate on the second (12) or fourth (14) surface, in particular a different bearing direction orthogonal to the bearing direction of the plate on the second (12) or fourth (14) surface. Electrical energy storage device (1) according to Claim 5, characterized in that this positioning means is a positioning hole (7) through which the stop (5; 8; 11; 12; 13; 14) passes. Electrical energy storage device (1) according to one of the preceding claims, characterized in that the abutment (5; 8; 11; 12; 13; 14) comprises:
- a first spacer (5) comprising the first surface (11),
- a second spacer (8) comprising the second surface (12) and the third surface (13),
the first spacer (5) and the second spacer (8) being against each other. Electrical energy storage device (1) according to Claim 7, characterized in that the abutment (5; 8; 11; 12; 13; 14) is constituted by the first spacer (5) and the second spacer (8) . Electrical energy storage device (1) according to one of Claims 7 or 8, characterized in that the second spacer (8) is firmly fixed to the plate (4). Vehicle comprising a battery, characterized in that the battery comprises an electrical energy storage device (1) according to one of the preceding claims.