EP2223376A1

EP2223376A1 - Device for storing electrical energy

Info

Publication number: EP2223376A1
Application number: EP08802749A
Authority: EP
Inventors: Herbert Damsohn; Conrad Pfender; Thomas Schiehlen; Martin Steinbach; Caroline Schmid
Original assignee: Behr GmbH and Co KG
Current assignee: Mahle Behr GmbH and Co KG
Priority date: 2007-10-19
Filing date: 2008-10-02
Publication date: 2010-09-01
Also published as: CN101828298A; US20100248000A1; DE102007050518A1; WO2009052928A1; US8129047B2

Abstract

The invention relates to a device for storing electrical energy, especially for a motor vehicle. Said device comprises at least one rechargeable storage cell (2) and a cooling unit (1) which is in thermal contact with the storage cell (2). The storage cell (2) is accommodated in a retaining element (4) and is in thermal contact with said retaining element (4), mating molded sections (1b, 5) on the retaining element (4) and the cooling unit (1) mechanically interconnecting the retaining element and the cooling unit in a self-locking manner.

Description

Device for electrical energy storage

The invention relates to a device for electrical energy storage according to the preamble of claim 1.

Especially for motor vehicles with at least partial electric drive increasing demands are placed on the performance of an electrical energy storage. The energy store may be conventional storage cells, modern lithium-ion accumulators or else high-performance capacitors or the like. Common to these electrical energy sources that they must be effectively cooled due to their high power density, in addition to the technical requirements for a good thermal contact of the memory cells also high reliability of the electrical insulation due to the high voltages occurring, especially in serial interconnection of a plurality of memory cells , as well as a cost-effective series production are to be considered.

DE 2007 009 315 A1 describes a device for cooling electrical elements of a motor vehicle, in which the cylindrical electrical

Elements are inserted in hollow cylindrical receptacles of a heat sink.

For electrical insulation are between the electrical element and the hollow cylindrical recording more insulating layers such as

Mica paper and adhesive for holding the electrical elements in the hollow cylindrical receptacles. It is the object of the invention to provide a device for storing electrical energy, in which a simple and secure mounting in conjunction with good thermal contact between the electrical storage cell and the heat sink is provided.

This object is achieved for an aforementioned device according to the invention with the characterizing features of claim 1. At first, a secure and relatively tolerance-insensitive fixing of the holding member to the storage cell takes place. The thermally highly conductive holding member is then fixed with the memory cell received therein to the heat sink by means of self-locking mechanical connection. A self-locking mechanical connection is particularly well suited in addition to the advantage of ease of installation to produce a very good thermal contact between the holding member and heat sink. As a rule, self-locking mechanical connections have large opposing friction surfaces, which favors the thermal contact.

In a preferred embodiment of the invention, the holding member is integrally connected to the memory cell, in particular by means of gluing. It may alternatively but also a purely mechanical, z. B. clamped holder of the memory cell act in the holding member.

In an expedient detailed design, the holding member comprises at least two sub-members which partially surround the memory cell. In one possible embodiment, in each case form-fitting means for connecting adjacent sub-members may be provided on the sub-members. Overall, this makes it possible in a simple manner a connection of the holding member and the memory cell, wherein the dimensional tolerances of the memory cell can be particularly large.

Generally, at least one of the corresponding formations comprises a wedge surface, wherein the holding member is fixed by means of the wedge surface at least frictionally and in planar thermal contact with the cooling body. Wedge surfaces can easily chanic self-locking bracket are made, which also allows their character after a good heat transfer. Particularly preferably, a wedge surface is provided both on the heat sink and on the holding member, which abut each other. In an advantageous detailed design, the memory cells are substantially cylindrically shaped, with the wedge surfaces being configured as a cone-shaped, outer-side widening of the holding member. In this way, the conical or conical section wedge surface of the support member can be inserted into a corresponding inverse hollow cone-shaped wedge surface of the heat sink, wherein at a suitable angle of the wedge surface or the cone a secure self-locking mechanical connection is made with good thermal contact.

In the interest of a simple and cost-effective production, the wedge surface may be formed as a bead-like formation of a sheet metal part.

In an alternative or supplementary embodiment, the corresponding formations at least partially comprise a thread. Such a thread may be, for example, cylindrical or conical and essentially provide even the contact surface between the holding member and the heat sink. However, it can also be designed, for example, as a short, end-side thread at the end of a conical wedge surface, so that large counteracting wedge surfaces of the holding member and heat sink are pressed against each other by only briefly screwing in the short thread. In such an embodiment, the angle of the wedge surfaces does not necessarily have to be self-locking, since the thread already achieves a self-locking mechanical connection.

In a particularly advantageous embodiment, it is provided that the self-locking mechanical connection of the holding member and heat sink is secured by a further, in particular cohesive fixing. It may be z. For example, the application of an amount of adhesive after insertion of the holding member in the heat sink under mechanical self-inhibition act or to a backfilling one between adjacent Holding members or memory cells and the heat sink remaining gap or similar measures. From the point of view of securing the self-locking mechanical connection is to be understood that the self-locking mechanical connection basically keeps alone, but in terms of a long service life under shock, vibration and / or corrosive influences, such as humidity condensate, can be additionally secured.

In a further embodiment, the holding member may be connected by a different mechanical connection with the heat sink, for example by a kind of bayonet closure. Alternatively, friction welding or rolling as connecting mechanisms are conceivable.

In general, the holding member is advantageously made of a metal, in particular of the group aluminum, copper or aluminum with rolled-on copper. Such metals are easily moldable in the interest of ease of manufacture and also have good thermal conductivity. The heat sink expediently consists of a similar metal, in particular aluminum.

Simple and inexpensive, the holding member may advantageously be formed as a sheet metal part. It may generally have a thickness between about 0.1 mm and about 2 mm to provide suitable support and temperature dissipation for conventional cylindrical storage cells for use in vehicle batteries.

Depending on the design of the memory cell, in particular for the case that the memory cell has an electrical potential on its outer wall, an electrically insulating layer can be provided between the holding member and the memory cell. This may in particular be in the form of a tube, z. B. in the manner of a shrunk on the memory cell shrink tube.

In an expedient embodiment, a region between the heat sink and a plurality of adjacent cells is filled with a filling material. Here- By the thermal dissipation of heat generated in the memory cells can be further improved and also a better mechanical protection of the entire device against impact, vibration or the like can be achieved. In order to reduce weight, the filling material may also be a foam.

In an advantageous development, the holding member has at least one circumferential clamping member in order to hold the holding member against the storage cell. The tendon may be provided as an alternative or in addition to a stoffschlüS s connection of the holding member to the memory cell. In general, the tendon supports the thermal contact between the holding member and the memory cell when the holding member is inserted into the heat sink in a self-locking mechanical manner, whereby deformations due to mechanical stresses in the holding member could occur.

In a further preferred embodiment, a plurality of memory cells are accommodated in the holding member. These may in particular be a plurality of cylindrical memory cells arranged serially one behind the other in a hollow cylindrical holding member.

Further advantageously, the shape of the holding member may be arranged above the storage cell, wherein a part of the holding member abutting the storage cell extends on both sides of the formation. In this way, the mechanically self-locking and thus thermally in contact with the cooling body in contact part of the holding member is particularly effectively supplied with derived from the memory cell heat, so that a total of a particularly high cooling capacity of a memory cell is achieved.

Alternatively or additionally, the holding member can pass completely through the heat sink and in particular protrude from both sides of the heat sink. By such a relative to a plane of the heat sink on both sides arrangement of the holding member and memory cells, the cooling capacity is used particularly effectively for a given space. Likewise, it can be alternatively or additionally provided that the heat sink two has opposite sides, wherein on each of the sides at least one holding member is self-locking mechanically fixed.

Alternatively, two or more heat sinks may be mechanically connected to a holding member. Such an arrangement is particularly advantageous for memory cells with high power densities, since such cells generate a considerable amount of waste heat.

Generally preferred, the heat sink is flowed through by effective heat dissipation of a fluid for exchanging heat. It may be a coolant, e.g. a mixture of water and glycol, for example, a low-temperature refrigeration cycle act or to a refrigerant of a refrigeration circuit, for. B. a vehicle air conditioning. The heat sink can be designed in particular as an evaporator of the refrigerant circuit.

Further advantages and features of the invention will become apparent from the embodiments described below and from the dependent claims.

Hereinafter, several preferred embodiments of the invention will be described and explained in more detail with reference to the accompanying drawings.

Fig. 1 shows a schematic plan view of an inventive

Contraption. FIG. 2 shows a schematic sectional view through a memory cell with a holding member fixed thereto. FIG. Fig. 3 shows a schematic sectional view through the device

Fig. 1.

4 shows a further embodiment of a device according to the invention.

Fig. 5 shows a development of a holding member according to another

Embodiment of the invention. Fig. 6 shows a sectional view through a further embodiment of the invention. Fig. 7 shows a sectional view through a further embodiment of the invention.

The exemplary embodiment of a device according to the invention for storing electrical energy schematically illustrated in FIG. 1 schematically shows a substantially plate-shaped heat sink 1 which extends in the plane of the drawing and on which a plurality of cylindrical electrical memory cells 2 are fixed vertically. The electrical memory cells 2 are lithium-ion batteries. The spaces between the memory cells 2 are filled with a plastic foam.

In concentric overlap with the memory cells 2, apertures 1a (see FIG. 3) are arranged in the cooling body 1, so that cooling channels 3 provided in the cooling body 1 run around the electrical memory cells 2 in the plan view according to FIG. The cooling channels 3 carry a liquid coolant (represented by an arrow F) of a low-temperature cooling circuit or also a refrigerant of a refrigeration circuit for dissipating heat from the storage cells.

The electric storage cells 2 are connected according to the invention by means of holding members 4 with the heat sink 1. FIG. 2 shows a schematic sectional view through a memory cell 2 with a holding member 4. The holding member 4 is in each case a plurality of part-cylindrical bent sheet metal parts made of aluminum, wherein a first part member 4a and a second part member 4b surround the cylindrical memory cell 2 around by bonding with this are connected. It may also be three or more sub-members, which together form the holding member 4, in which the cylindrical memory cell 2 is accommodated. Also, a holding member 4 of only one part member is possible, for example in the form of a longitudinally cut cylindrical sleeve (not shown).

In a variant, not shown, between the memory cell 2 and the preferably made of aluminum or copper holding members 4 a z. B. insulation film designed as a shrink tube, in particular if the memory cell 2 has a non-potential-free outer shell. In general, in such a device at least some of the memory cells will be connected in series with each other, so that an electrical contact between a pole of the memory cell and the heat sink is to be avoided.

The holding member 4 and its sub-members 4a, 4b are formed as a sub-cylinder and have over a portion of their height a wedge-shaped formation 5 for mechanically self-locking fixing of the holding member 4 on the heat sink 1. As shown in Fig. 3, the opening 1a of the heat sink 1 has a corresponding to the conical section wedge surface 5 hollow conical shape 1 b, in which the conical section wedge surface 5 is inserted, wherein by frictional engagement a mechanical self-locking and secure support at the same time good thermal contact between Holding member 4 and heat sink 1 is formed.

The holding member 4 also has, adjacent to the wedge surface 5, a bead-like formation 6, by means of which an improved guidance, an axial positioning and a uniform spacing of the cells when inserted into the heat sink 1 can be achieved. The sub-members 4a, 4b of the support member 4 are each sheet metal shaped parts, wherein the wedge surface 5 in the manner of a bead z. B. can be produced by forming in a simple manner.

In the preferred embodiment, the opening angle of the wedge surface 5 is optimized in the interest of good mechanical self-locking with good thermal contact. Such an optimized angle is between about 3 ° and about 10 ° and is more preferably about 7 °.

In Fig. 3 is a variant of the embodiment is shown in dashed lines, in which the cylindrical wall of the support member 4, 4 'continues on both sides of the wedge surface 5 and the heat sink 1, wherein also a further memory cell 2' used in the continuous area is. It may also be provided that only one memory cell is located in the holding member, but wherein the wedge surface 5 in a central region the memory cell is positioned in registration with the memory cell. Overall, this means that the region of the formation 5 which is in thermal contact with the heat sink 1 is supplied with heat supplied by the memory cells 2 from both sides, so that a particularly effective heat dissipation is possible for a given space.

In the modification of the embodiment shown in FIG. 4 shown in FIG. 3, the heat sink 1 also apertures 1 a, wherein, however, in the same opening 1 a from each side of a tapered Aus formation is provided. Accordingly, a holding member 4 of each of the two sides can be used mechanically self-locking, so that on each of the opposite sides of the heat sink 1 memory cells 2 extend. As a result, a particularly good utilization of the cooling capacity of the heat sink 1 is achieved with a given space.

In the embodiment of the invention shown in Fig. 5, the holding member 4 consists of four sub-members 4a, 4b, 4c, 4d. These have in their middle region similar to the dashed line in Fig. 3 shown modification a central wedge surface 5 for mechanically self-locking determination in a heat sink 1.

The individual sub-elements 4a-4d each have marginal positive and negative positive-locking means 7, 8 in the form of pitch circles with which they are positively attached to each other in the manner of puzzle pieces. The diameter of one of the part-circular form-fitting formations 7, 8 must be smaller than four times the sheet thickness of the sub-members 4a - 4d, in order to achieve a secure form-fitting suspension.

Between the adjacent sub-members 4a-4d there remains over each two thirds of the height of the holding member 4 a gap 9, in the region of which the adjacent holding members 4a-4d do not abut one another. Overall, by this positive concatenation of the holding members 4a - 4d a resilient in Umfangsgehchtung, the memory cell 2 surrounding cuff is formed, through which even with large dimensional tolerance of the memory cell 2 a secure mechanical and thermally well contacted recording of the storage cherzelle 2 is possible. Depending on the requirements, the holding member 4 according to FIG. 5 can be fixed only mechanically or by means of adhesive bonding to the memory cell 2.

In the exemplary embodiment shown in FIG. 6, the holding member 4 surrounds the storage cell 2 as in the embodiments described above, wherein in addition a plurality of clamping rings 10 surrounding the holding members are mounted. As a result of this, mechanical stressing of the holding members 4 against the wall of the storage cells 2 provides a particularly secure support and a particularly good thermal contact. In particular, this avoids that the thermal contact is deteriorated by a deformation or mechanical stress in the course of insertion of the wedge surface 5 in the heat sink 1.

In the embodiment shown in Fig. 7, two heat sink 1 are mechanically connected to a holding member 4 self-locking. Preferably, the heat sinks are arranged in the middle of the memory cell in the axial direction of the memory cell 2, in order to avoid a large temperature gradient along the memory cell. Of course, the heat sink may alternatively be attached to any other location on the support member.

It is understood that the individual features of the various described embodiments can be combined in a meaningful way depending on the requirements.

Claims

Patent claims

1. A device for electrical energy storage, in particular for a motor vehicle, comprising at least one rechargeable electric storage cell (2) and one with the memory cell (2) in thermal contact heat sink (1), wherein the memory cell (2) received in a holding member (4) is and in thermal contact with the holding member (4), characterized in that on the holding member (4) and on the heat sink (1) corresponding formations (1b, 5) are provided for self-locking mechanical connection of the holding member and heat sink.

2. Device according to one of the preceding claims, characterized in that the holding member (4) with the memory cell (2) is integrally connected, in particular by means of gluing.

3. Device according to one of the preceding claims, characterized in that the holding member (4) comprises at least two sub-members (4a, 4b, 4c, 4d) which surround the memory cell (2) each partially.

4. Apparatus according to claim 3, characterized in that on the sub-members (4a, 4b, 4c, 4d) each positive-locking means (7, 8) are provided for connecting adjacent sub-members.

5. Device according to one of the preceding claims, characterized in that at least one of the corresponding formations comprises a wedge surface (1b, 5), wherein the holding member (4) by means of the wedge surface (1b, 5) at least frictionally and in planar thermal contact on the Heatsink (1) is fixed.

6. Apparatus according to claim 5, characterized in that both on the heat sink (1) and on the holding member (4) has a wedge surface (1 b, 5) is provided.

7. Device according to one of claims 5 or 6, characterized in that the memory cell (2) is substantially cylindrically shaped and the wedge surface (5) is designed as a cone-shaped outer widening of the holding member (4).

8. Device according to one of claims 5 to 7, characterized in that the wedge surface (1 b, 5) is formed as a bead-like formation of a sheet metal part.

9. Device according to one of the preceding claims, characterized in that the corresponding formations (1b, 5) at least partially comprise a thread.

10. Device according to one of the preceding claims, character- ized in that the self-locking mechanical connection is secured by a further, in particular cohesive down.

11. Device according to one of the preceding claims, character- ized in that the holding member (4) consists of a metal, in particular from the group aluminum, copper or aluminum with rolled copper.

12. Device according to one of the preceding claims, characterized in that the holding member (4) is formed as a sheet metal part.

13. Device according to one of the preceding claims, characterized in that the holding member (4) has a thickness between about 0.1 mm and about 2 mm.

14. Device according to one of the preceding claims, characterized in that between the holding member (4) and the memory cell (2) an electrically insulating layer, in particular in the form of a tube, is arranged.

15. Device according to one of the preceding claims, character- ized in that a region between the heat sink (1) and a plurality of adjacent cells (2) is filled with a filling material.

16. Device according to one of the preceding claims, character- ized in that the holding member (4) at least one circumferential

Tensioning member (10) to hold the holding member (4) against the storage cell (2).

17. Device according to one of the preceding claims, character- ized in that a plurality of memory cells (2) are received in the holding member (4).

18. Device according to one of the preceding claims, characterized in that the formation (5) of the holding member (4) over the memory cell (2) is arranged, wherein a to the memory cell

(2) abutting part of the holding member (4) on both sides of the molding (5).

19. Device according to one of the preceding claims, character- ized in that the holding member (4) the heat sink (1) completely passes through and in particular protrudes from both sides of the heat sink (1).

20. Device according to one of the preceding claims, character- ized in that the cooling body (1) has two opposite sides, wherein on each of the sides at least one holding member (4) is self-locking mechanically fixed.

21. Device according to one of the preceding claims, character- ized in that the cooling body (1) can be traversed by a fluid for the exchange of heat.

22. The apparatus according to claim 21, characterized in that the fluid is a coolant of a low-temperature cooling circuit.

23. The device according to claim 22, characterized in that the coolant is a water-glycol mixture.

24. The device according to claim 21, characterized in that the fluid is a refrigerant of a refrigerant circuit, in particular a vehicle air conditioner.