BATTERY

Abstract

A battery comprises a cell stack that encompasses layers stacked above each other in a stacking direction, whereby the layers consist alternately of an electrode or of a separator. At least one of the electrodes that is arranged between the ends of the cell stack protrudes beyond the remaining electrodes on one side perpendicular to the stacking direction, and said protruding electrode is thermally contacted with a cooling element that is arranged parallel to the stacking direction and next to the cell stack. A battery module has several such batteries.

Claims

1. A battery comprising: a cell stack that encompasses layers stacked above each other in a stacking direction, whereby the layers consist alternately of an electrode or of a separator, whereby at least one of the electrodes that is arranged between the ends of the cell stack protrudes beyond the remaining electrodes on one side perpendicular to the stacking direction, and said protruding electrode is thermally contacted with a cooling element that is arranged parallel to the stacking direction and next to the cell stack.

2. The battery according to claim 1, wherein every second electrode in the stacking direction protrudes on one side beyond the remaining electrodes perpendicular to the stacking direction, and said protruding electrode is thermally contacted with the cooling element.

3. The battery according to claim 1, wherein the separators that are directly adjacent to the protruding electrode protrude beyond the remaining electrodes on one side.

4. The battery according to claim 1, wherein the protruding electrodes comprise a metal arrester that is provided with an active material, whereby the protruding portion is at least partially free of the active material.

5. The battery according to claim 1, wherein the protruding electrode is contacted with the cooling element via a contacting element.

6. The battery according to claim 5, wherein the contacting element is a spring sheet metal with a body with which the protruding electrode is mechanically in contact and which is supported on the cooling element by means of a springy contactor.

7. The battery according to claim 1, wherein the cooling element has an undulating or jagged configuration on the side facing the cell stack.

8. The battery according to claim 1, further comprising a housing in which the cell stack is arranged, whereby the cooling element is formed by means of a wall of the housing.

9. The battery according to claim 8, further comprising a cooling plate that is in contact with the wall, whereby the wall is arranged between the cooling plate and the cell stack.

10. A battery module having several batteries according to claim 9, whereby the cooling plates are formed in one single piece with each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments of the invention will be explained in greater detail below on the basis of a drawing. The following is shown:

[0038] FIG. 1: a schematically simplified view of a motor vehicle having a high-voltage battery with several identical battery modules,

[0039] FIG. 2: portions of a schematic sectional view of one of the battery modules having several identical batteries which each have a cell stack,

[0040] FIGS. 3-8: in each case, a sectional view of different embodiments of the battery, and

[0041] FIG. 9: portions of a schematic sectional view of another embodiment of the battery.

[0042] Parts that correspond to each other are designated by the same reference numerals in all of the figures.

DETAILED DESCRIPTION OF THE INVENTION

[0043] FIG. 1 shows a schematically simplified view of a motor vehicle 2 in the form of a passenger car. The motor vehicle 2 has a number of wheels 4 of which at least some are powered by means of a drive 6 comprising an electric motor. Thus, the motor vehicle 2 is an electric vehicle or a hybrid vehicle. The drive 6 has a converter by means of which the electric motor is supplied with power. The converter of the drive 6, in turn, is supplied with power by means of an energy storage means 8 in the form of a high-voltage battery. For this purpose, the drive 6 is connected to an interface 10 of the energy storage means 8 that is installed in an energy storage housing 12 of the energy storage means 8, said housing 12 of the energy storage means being made of a noble metal. Multiple battery modules 14 are arranged inside the housing 12 of the energy storage means, some of which are electrically connected to each other in series and these, in turn, are electrically connected to each other in parallel. The electric assembly of the battery modules 14 is electrically contacted with the interface 10 so that, during operation of the drive 6, the battery modules 14 are discharged or charged (recuperation). Owing to the electric interconnection, the electric voltage, amounting to 400 V, which is supplied at the interface 10, is a multiple of the electric voltage supplied with each of the identically designed battery modules.

[0044] FIG. 2 shows portions of a schematic sectional view of one of the battery modules 14. The battery module 14 comprises several batteries 16 that are identical to each other, three of which are depicted here. In a manner not shown here, some of the batteries 16 are electrically connected to each other in parallel and otherwise electrically connected in series, so that the electric voltage supplied by means of each battery module 14 corresponds to a multiple of the electric voltage supplied by means of one of the batteries 16. Each battery 16 comprises a cell stack 18 that has several layers 20 that are stacked above each other in a stacking direction 22. The stacking direction 22 is the same for all of the batteries 16 and parallel to the sectional line of the sectional depiction. The batteries 16 are also arranged so as to be in contact with each other in the stacking direction 22.

[0045] The layers 20 are configured so as to be flat and planar as well as arranged perpendicular to the stacking direction 22. Each of the layers 20 here is essentially rectangular. Each cell stack 18 has between 140 and 200 such layers 20, of which only some are shown here. Each of the layers 20 is formed either by an electrode 24 or by a separator 26, and the separators 26 and the electrodes 24 are alternately arranged in the stacking direction 22. The electrodes 24 are divided into anodes 28 and cathodes 30 which are likewise alternately arranged in the stacking direction 22, so that one of the cathodes, as the appertaining electrode 24, follows one of the anodes 28 in the stacking direction 22 and vice versa. The electrodes 24 each have an arrester 32 that is made of a metal foil. In the case of the anode 24, this is a copper foil and, in the case of the cathode 30, it is an aluminum foil. In the stacking direction 22, both sides of the arrester or arrester foils are provided with a layer 34 containing an active material such as NMC which additionally comprises a binder and a conductive additive such as electrically conductive carbon black. Therefore, the cell stack 18 structured in this manner has several battery cells, whereby each battery cell is associated with one of the anodes 28 and with one of the cathodes 30 that are adjacent to each other in the stacking direction 22. Moreover, each battery cell is associated with one or two of the separators 26.

[0046] All of the anodes 28 are lengthened on one side perpendicular to the stacking direction 22 relative to the remaining electrodes 24, namely the cathodes 30, so that these are positioned relative to the remaining electrodes 24. Consequently, every second electrode 24 in the stacking direction 22 protrudes on one side beyond the remaining electrodes 24, namely the cathodes 30, perpendicular to the stacking direction 22, thereby forming a protruding portion 36. In other words, the anodes 28 form the protruding electrodes while the cathodes 30 form the remaining electrodes. Since all of the anodes 28 form the protruding electrodes, some of the electrodes 24 arranged between the ends of the cell stack 18 also have the protruding portion 36 perpendicular to the stacking direction 22 on one side relative to the remaining electrodes, namely, the cathodes 30.

[0047] Each protruding portion 36 is free of the layer 34 and is formed only by the appertaining arrester 32. For this reason, each protruding portion 36 is free of the active material. At the end of each protruding portion 36, that is to say, on the side opposite from the rest of the cell stack 18, said protruding portion 36 is electrically and consequently also thermally contacted with a cooling element 38. The cooling element 28 is formed by a wall 40 that is configured so as to be planar and flat, namely, the bottom of an essentially cuboidal housing 42 of the appertaining battery 16. In this context, the appertaining cell stack 18 is arranged inside the appertaining housing 42, and the wall 40 is arranged parallel to the stacking direction 22. As a result, the wall 40 is arranged next to the cell stack 18. The housings 42 are configured so as to be closed and are each made of metal. In an embodiment variant, the housings 42 are configured as pouch housings and are at least partially made of a metal foil.

[0048] Inside each housing 42, there is also a busbar 44 that is electrically contacted with a connection 46. The connection 46 penetrates all the way through the housing 42 and is electrically insulated vis-à-vis the housing. The busbar 44 is electrically contacted with all of the cathodes 30, which have an appropriate connection tab for this purpose. Each battery 16 also comprises an additional connection (not shown here) that is electrically directly contacted with the housing 42 and that, like the connection 46, is situated on the side of the housing 42 opposite from the wall 40. Therefore, this connection is electrically contacted with the anodes 28. Energy is drawn from the battery 16 via the connection 46 as well as via the additional connection not shown here.

[0049] Each battery 16 also comprises a cooling plate 48, whereby all of the cooling plates 48 of the batteries 16 of the same battery module 14 are configured in one single piece with each of them and by means of the bottom or another wall of a battery module housing. In this context, the cooling plates 48 are situated on the outside of the appertaining wall 40. In other words, the wall 40 of each battery 16 is arranged between the appertaining cell stacks 18 and the cooling plate 48, and each of the housings 42 protrudes beyond the wall of the battery module housing that forms the cooling plates 48. In the case of another one of the walls of the housing 42 that delimits the housing 42 in the stacking direction 22, at least some of the individual housings 42 are in contact with each other, so that the battery module 14 is rendered more compact.

[0050] Electric energy is fed in or drawn from the batteries 16 during operation of the battery module 14, so that the appertaining cell stack 18 heats up. It is via the protruding electrodes, in other words, the anode 28, that heat is dissipated from the cell stack 18 to the cooling element 38, namely, to the wall 40 of the appertaining housing 42, and from there to the cooling plate 48, in other words, to the housing of the battery module 14, which is cooled by means of a cooling apparatus not shown here. This translates into a relatively efficient cooling of the cell stack 18, and all of the batteries 16 display essentially the same temperature.

[0051] FIG. 3 shows portions of a schematic sectional view along the stacking direction 22 pertaining to another embodiment of the battery 16. In this case, the side, that is to say, the surface, of the walls 40 facing the cell stack 18 is configured so as to be undulating, so that the distance of the wall 40 to the cell stack 18 varies. As a result, the arrester 32 of the anode 28 can be made with a relatively large manufacturing tolerance, so that the size of the protruding portion 36 varies. The wave peaks here are in the position where the anodes 28 are located. Due to the undulating configuration, each arrester 32 is mechanically and thus thermally and electrically securely in contact with the wall 40, even in view of the relatively large manufacturing tolerance, whereby, in the case of an enlarged protruding portion 36, the free end enters one of the adjacent wave valleys and its entire surface is in contact with the wall 40. This prevents an uncontrolled bending of the foil that forms the arrester 32. Moreover, this also establishes a relatively large flat physical contact between the arrester 32 and the wave flanks of the wall 40, thus improving the heat dissipation.

[0052] FIG. 4 shows another alternative corresponding to FIG. 3. In this context, the side of the wall 40 facing the cell stack 18 is configured so as to be jagged and formed by means of jags adjacent to each other. In other words, the cross section along the stacking direction 22 is triangular, whereby the individual triangles are at a distance from each other. The tips of the triangles here are located at the desired position of the anode 28. This allows an appropriate tolerance compensation, bringing about a relatively full-surface contact of the individual arresters 32 with the wall 40.

[0053] FIG. 5 shows another alternative of the battery corresponding to FIGS. 3 and 4. Here, too, the wall 40 is configured so as to be jagged, whereby the cross section along the stacking direction 22 likewise has triangles which, however, are directly adjacent to each other. As a result, the tips of the triangles do not necessarily have to be situated at the position of the anodes 28 in order to establish the contact.

[0054] In the variant shown in FIG. 6, the cross section of the wall 40 that forms the cooling element 38 is serrated along the stacking direction 22 on the side facing the cell stack. Due to the ramps that are formed, the wall 40 successively approaches the cell stack 18, so that there is always contact with the arresters 32.

[0055] In the variant shown in FIG. 7, the individual serrated teeth are at distance from each other in comparison to the case in FIG. 6, so that the flanks of the serrated teeth are configured more steeply. Consequently, the contact surface is further enlarged.

[0056] In the variant shown in FIG. 8, the side of the wall 40 facing the cell stack 18 has individual steps. If the protruding portion 36 is configured so as to be relatively large, it passes around the step. This ensures a relatively large surface area of contact with the wall 40, whereby, however, undesired detachment can occur in the area of the individual edges of the steps.

[0057] FIG. 9 shows a sectional view along the stacking direction 22 of a last embodiment of the battery 16. The cell stack 18, in turn, has the electrodes 24, namely, the anodes 28 as well as the cathodes 30, which alternate in the stacking direction 22. The electrodes 24, in turn, each have the arrester 32 that is formed by the appertaining foil and that is provided with the layer 34 on both sides relative to the stacking direction 22. Moreover, the arrester 32 of the anode 28 also forms the protruding portion 36 on the side facing the cooling element 38, in other words, facing the wall 40. Between the anode 28 and the cathodes 30, there are, in turn, separators 26 which, however, protrude on at least one side beyond the remaining electrodes, that is to say, the cathodes 30. In this context, the separators 26 also protrude all around or at least on one side beyond the side of the cell stack 18 opposite from the wall 40. In summary, the separators 26 that are directly adjacent to the protruding electrodes, in other words, the anode 28, protrude beyond the remaining electrodes, in other words, the cathodes 30, at least on one side. Consequently, the separators 26 prevent the active material of the cathodes 30 from accumulating on the anodes 28, namely, on the protruding portion 36.

[0058] Moreover, the protruding portions 36 are not mechanically, electrically and thermally contacted with the wall 40 directly, but rather via a contacting element 50 that is made in one single piece out of a spring sheet metal. The contacting element 50 has a flat body 52 that is arranged parallel to the wall 40 and that is situated between the cell stack 18 and the wall 40. The body 52 is supported on the wall 40 and thus on the cooling element 38 by means of several springy contactors 54. The contactors 54 are formed in one single piece with the body 52 and the contacting element 50 is configured as a stamped-bent part. The protruding portions 36 are mechanically and directly in contact with the body 52 and are consequently electrically and thermally contacted with the contacting element 50. The contactors 54 bring about physical contact of the contacting body 52 with the cooling element 38, so that the contacting body 52 is thermally and electrically contacted with the cooling element 38. Consequently, the protruding electrodes, namely, the anodes 28, are electrically and thermally contacted with the cooling element 38.

[0059] In a variant not shown here, the variants depicted in FIGS. 2 to 8 have protruding separators 26. In other variants not shown here, in the variant depicted in FIG. 9, the wall 40 is configured according to the embodiment depicted in FIGS. 3 to 8. In other variants not shown here, the body 52 is accordingly shaped on the side facing the cell stack 18 corresponding to the side of the wall 40 shown in FIGS. 3 to 8.

[0060] The invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by the person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in conjunction with the individual embodiments can also be combined in another manner without departing from the subject matter of the invention.

LIST OF REFERENCE NUMERALS

[0061] 2 motor vehicle

[0062] 4 wheel

[0063] 6 drive

[0064] 8 energy storage means

[0065] 10 interface

[0066] 12 housing of the energy storage means

[0067] 14 battery module

[0068] 16 battery

[0069] 18 cell stack

[0070] 20 layer

[0071] 22 stacking direction

[0072] 24 electrode

[0073] 26 separator

[0074] 28 anode

[0075] 30 cathode

[0076] 32 arrester

[0077] 34 layer

[0078] 36 protruding portion

[0079] 38 cooling element

[0080] 40 wall

[0081] 42 housing

[0082] 44 busbar

[0083] 46 connection

[0084] 48 cooling plate

[0085] 50 contacting element

[0086] 52 body

[0087] 54 contactor