METHOD FOR PRODUCING A CATHODE APPARATUS, METHOD FOR PRODUCING AN ELECTRODE ASSEMBLY, AND BATTERY

Abstract

The invention relates to a method for producing a cathode apparatus (16) for a battery (8), especially of a motor vehicle (2), whereby a cathode strip (20) is provided, whereby a cathode (16a) is cut out of the cathode strip (20), whereby the cathode (16a) is placed between two strip-shaped separator foils (16d), and whereby, in a joint step, the two separator foils (16d) are cut to size in an area that protrudes beyond the cathode (16a), thereby forming appropriate separator foil cutouts (16f), and these two separator foil cutouts (16f) are also joined to each other in this area, especially fused together. Furthermore, the invention relates to a method for producing a cathode apparatus (16), whereby a single strip-shaped separator foil (16d) is folded and arranged on the cathode (16a) in such a way that the folded edge of the separator foil (16d) adjoins a contact face (38) of the cathode (16a) and so that the cathode (16a) is covered on both sides by a separator foil section (16g) of the separator foil (16d). Furthermore, the invention relates to a method for producing an electrode assembly (12) having such a cathode apparatus (16), to a battery (8) having such an electrode assembly (12), as well as to a motor vehicle (2) having such a battery (8).

Claims

1. A method for producing a cathode apparatus for a battery, especially of a motor vehicle, comprising: providing a cathode strip, cutting a cathode out of the cathode strip, placing the cathode between two strip-shaped separator foils, and in a joint step, cutting the two separator foils to size in an area that protrudes beyond the cathode, thereby forming appropriate separator foil cutouts, and joining the resulting two separator foil cutouts to each other in this area by fusing them together.

2. A method for producing a cathode apparatus for a battery, especially of a motor vehicle, comprising: providing a cathode strip, cutting a cathode out of the cathode strip, folding and arranging a single strip-shaped separator foil on the cathode in such a way that a folded edge of the separator foil adjoins a contact face of the cathode and that the cathode is covered on both sides by a separator foil section of the separator foil.

3. The method according to claim 2, further comprising folding the strip-shaped separator foil, thus creating a folded edge along a lengthwise direction of the strip, and in a joint step, cutting the separator foil to size in an area of the faces of the cathode extending beyond the cathode, said area facing away from the contact face, and joining the resulting two separator foil sections to each other by fusing them together.

4. The method according to claim 3, wherein, in the joint step, a laser or a heated rotary blade is used to cut and to join the two separator foil sections.

5. The method according to claim 3, further comprising laminating the cathode with the separator foil sections in one single step before the separator foil is cut to size.

6. The method according to claim 2, further comprising folding the strip-shaped separator foil, thus creating a folded edge that runs perpendicular to a lengthwise direction of the strip, cutting the separator foil is cut to size, and laminating the cathode with the separator foil sections.

7. A method for producing an electrode assembly, comprising providing an anode, producing a cathode apparatus according to claim 2 which is cut to size in such a way that a dimension of its separator foil sections matches a dimension of the anode, and stacking and aligning the anode and the cathode apparatus relative to each other by means of a stop.

8. A battery having an electrode assembly produced according to claim 7.

9. A motor vehicle having a battery according to claim 8.

10. The method according to claim 1, wherein, in the joint step, a laser or a heated rotary blade is used to cut and to join the two separator foil cutouts.

11. The method according to claim 1, further comprising laminating the cathode with the separator foil cutouts in one single step before the separator foils are cut to size.

12. A method for producing an electrode assembly, comprising providing an anode, producing a cathode apparatus according to claim 1 which is cut to size in such a way that a dimension of its separator foil cutouts matches a dimension of the anode, and stacking and aligning the anode and the cathode apparatus relative to each other by means of a stop.

13. A battery having an electrode assembly produced according to claim 12.

14. A motor vehicle having a battery according to claim 13.

Description

[0034] Embodiments of the invention will be explained in greater detail below with reference to a drawing. The following is shown there:

[0035] FIG. 1 a schematic view of a motor vehicle with a battery having battery cells, whereby the battery cells have an electrode assembly with an anode and a cathode apparatus,

[0036] FIG. 2 a schematic view of a first variant of a method for producing the cathode apparatus, whereby a cathode is placed between two separator foils and the separator foils are cut to size, being joined to each other in this process,

[0037] FIG. 3 a schematic view of a first embodiment of a second variant of the method for producing the cathode apparatus, whereby a single strip-shaped separator foil is folded along the lengthwise direction of the strip and is arranged on both sides of the cathode,

[0038] FIG. 4 a schematic view of a second embodiment of the second variant of a method for producing the cathode apparatus, whereby the single strip-shaped separator foil is folded along the lengthwise direction of the strip, and whereby the cathode is placed between the separator foil sections of the separator foil,

[0039] FIG. 5a a top view of a cathode apparatus having a cathode that is placed between the folded separator foil, whereby the separator foil sections of the separator foil that adjoin the flat sides of the cathode are joined to each other, forming a pocket in this process,

[0040] FIGS. 5b, c sectional views of the cathode apparatus as seen in the sectional planes Vb or Vc of FIG. 5a, and

[0041] FIG. 6 schematically, a method for producing the electrode assembly.

[0042] Parts and dimensions that correspond with each other are always designated with the same reference numerals in all of the figures.

[0043] The motor vehicle 2 shown in FIG. 1 is electrically powered. For this purpose, the motor vehicle 2 has an electric motor 4 that is connected to a battery 8 via a power inverter 6. The battery 8 has a plurality of battery cells 10, whereby, for the sake of greater clarity, only two battery cells 10 are shown. Each of the battery cells 10 holds an electrode assembly 12. Its anodes 14 and its cathode apparatuses 16 are stacked alternatingly on top of each other.

[0044] Each of the anodes 14 has an anode foil 14a that is configured, for example, as a copper foil and that is coated on both sides, in other words, on its flat sides, with a first active material 14b, for example, graphite.

[0045] Each of the cathode apparatuses 16 has a cathode 16a having a cathode foil 16b, for example, an aluminum foil. It is coated on both sides with a second active material 16c, for example, with a lithium transition metal oxide. Here, the second active material 16c is shown with a dotted surface. In summary, the cathode foil 16b and the second active material 16c form the cathode 16a.

[0046] Moreover, the cathode apparatuses 16 have separator foils 16d that cover the cathodes 16a on their flat sides. They contain, for example, polyethylene and/or polypropylene. Thus, the separator foils 16d are arranged between the anodes 14 and the cathodes 16a.

[0047] The first face 18 of the anode foil 14a as well as the first face 18 of the cathode foil 16b each have a contact 14c or 16e, respectively, in order to electrically contact the electrodes, in other words, the anodes 14 and the cathodes 16a.

[0048] FIG. 2 schematically shows a process sequence for producing the cathode apparatus 16 according to a first variant. In a first step, a cathode strip 20 that is wound up on a roll (coil) is provided. This strip has the cathode foil 16b that is coated with the second active material 16c. In a second step, the cathode strip 20 is unwound and the cathode 16a is cut out at the end by means of a cutting device 22.

[0049] In a third step, the cathode 16a is placed between two strip-shaped separator foils 16d that each have a lengthwise direction L of the strip. For this purpose, the separator foils 16d as well as the cathode 16a are moved by a conveyor 24 and stacked on top of each other. In this process, the separator foils 16d are each unwound from a roll (coil). The conveyor 24 has two vacuum belts, whereby their distance from each other decreases in the lengthwise direction of the strip. As a result, the separator foils 16d are pressed together in front of and behind the cathode 16a relative to the lengthwise direction of the strip.

[0050] Moreover, the flat cathode 16a sides that adjoin the first face 18 are completely covered by means of the two separator foils 18d. The contact 16e projects sideways from the plane of the drawing beyond the two separator foils 16d, that is to say, in a direction that is perpendicular to the lengthwise direction L of the strip and in a plane spanned by the cathode 16a.

[0051] In a fourth step, the two separator foils 16d are cut to size by means of a heated rotary blade 26 that is shown schematically and, for the sake of greater clarity, not true-to-scale, thereby forming appropriate separator foil cutouts 16f. In this process, the two separator foil cutouts 16f fuse together as a result of the thermal effect of the rotary blade. The two separator foils 16d are cut to size and are then fused in an area 28 that projects beyond the cathode 16a in front of and behind the cathode 16a relative to the lengthwise direction L of the strip.

[0052] In an alternative, not shown here, the two separator foils 16d are additionally cut to size in the area of a second face 30 that is opposite from the first face 18 and fused together. In this manner, the fused separator foil cutouts 16f form a pocket which securely holds the cathode 16a against slipping.

[0053] Subsequently, the cathode apparatus 16 is placed into a magazine 32 and prepared for the production of an electrode assembly 12.

[0054] In summary, the two separator foil cutouts are cut to size and fused in one work step.

[0055] FIG. 3 schematically shows a process sequence for producing the cathode apparatus 16 according to a first embodiment of a second variant of the method. In this process, to start with, the first two steps of the first variant are carried out, that is to say, the cathode 16a is cut out of the cathode strip 20.

[0056] In a third step of the first embodiment of the second variant, a single strip-shaped separator foil 16d is folded by means of a folding device 34, thus forming a folded edge 36. Here, the separator foil 16d is folded in such a way that the folded edge 36 runs in the lengthwise direction L of the strip. The folded separator foil 16d is arranged on the cathode 16a in such a way that the folded edge 36 of the separator foil 16a adjoins a contact face 38 of the cathode 16a, whereby here, the contact face 38 is the second face 30 that is opposite from the first faces 18. Here, the cathode 16a is covered on each side by a separator foil section 16g of the separator foil 16d.

[0057] Subsequently, in a fourth step, the cathode 16a is laminated with the two separator foil sections 16g by means of a laminating system 40.

[0058] Subsequently, in a joint fifth step, the separator foil 16d or the separator foil sections 16g are cut to size by means of a laser 42 in an area 28 in front of and behind the cathode 16 relative to the lengthwise direction L of the strip. In this manner, the separator foil 16d or the separator foil sections 16g are cut to size in an area that projects beyond the cathode 16a and that comprises faces that adjoin the contact face 38. In this process, the two separator foil sections 16g fuse together as a result of the effect of the laser 42 on the separator foil sections 16g.

[0059] In a sixth step, the cathode apparatus 16 is placed into a magazine 32 and provided for producing an electrode assembly 12.

[0060] FIG. 4 schematically shows a process sequence for producing the cathode apparatus 16 according to a second embodiment of the second variant of the method. Here, the first two steps are carried out analogously to the first embodiment.

[0061] In a third step, the individual strip-shaped separator foil 16d is folded by means of the folding device 34, thereby forming the folded edge 36, but in such a way that the folded edge 36 runs perpendicular to the lengthwise direction L of the strip and parallel to the flat side of the separator foil 16d, that is to say, in the crosswise direction Q of the strip. For this purpose, conveying rollers 44 place the end of the separator foil 16 into a receptacle 46 that is slanted counter to the conveying direction, thereby forming the two separator foil sections 16g, a process in which the slant of the receptacle 46 facilitates the folding procedure.

[0062] In a fourth step, the separator foil is cut to length perpendicular to the lengthwise direction L of the strip, namely, by means of another cutting device 22, and the cathode 16a is placed between the two separator foil sections 16g.

[0063] In a fifth step, the cathode 16a is laminated with the separator foil sections 16g by means of laminating rollers 48. Here, the conveying roller 42 that is also used as the laminating roller 44 is the one that faces away from the side of the separator foil 16d from which the cathode 16a is placed between the separator foil sections 16g.

[0064] In a sixth step, not shown here, the cathode apparatus 16 is placed into a magazine 32 in an analogous manner and provided for producing an electrode assembly 12.

[0065] FIGS. 5a to 5c show the cathode apparatus 16 produced according to the second variant of the method. The second face 30—which was used as the contact face 38 and which is opposite from the first face 18—adjoins the folded edge 36 of the separator foil 16d. Therefore, the separator foil 16d surrounds the cathode 16a. For the sake of greater visibility of the second active material 16c, the separator foil 16d is shown in FIG. 5a as if it were transparent. The areas 50 of the two separator foil sections 16g that are fused together, that is to say, that are joined together, are shown with cross-hatching here. They extend in the area of the faces that adjoin the first face 18 and the second face 30. Since the two separator foil sections 16g and the folded edge 36 are fused, the separator foil 16d forms a pocket which securely holds the cathode 16a against slipping. The flat sides of the cathode 16a that have been laminated with the separator foil sections 16g are designated by the reference numeral 52.

[0066] FIG. 6 schematically shows a process sequence for producing the electrode assembly 12. The anode 14 is provided in this process. The cathode apparatus 16 was produced in one of these methods as described above in such a way that its dimension, that is to say, its extension in a plane spanned by its separator foil cutouts 16f or by its separator foil sections 16g, matches the dimension of the anode 14, that is to say, its extension in a plane spanned by the anode foil 14a.

[0067] For this purpose, in the first variant and in the first embodiment of the second variant of the method for producing the anode apparatus 16, the separator foil cutouts 16f or the separator foil sections 16g are appropriately cut to size. When the anode apparatus 16 is produced according to the second embodiment of the second variant of the method, the extension of the separator foil 16d in the crosswise direction Q of the strip is selected accordingly or, as an alternative, cut to size accordingly. For this purpose, for example, the laser 42 is used so that the two separator foil sections 16g are fused together in the appertaining areas.

[0068] Subsequently, the cathode apparatus 16 and the anode 14 are stacked on top of each other. In this process, the cathode apparatus 16 and the anode 14 are aligned relative to each other by means of a stop 54. For the sake of greater clarity, the portion of the stop 54 that is arranged behind the anode 14 or behind the cathode apparatus 16 as seen in the view towards the plane of the drawing is shown with more cross-hatching than the L-shaped portion of the stop 54 that runs perpendicular to the plane of the drawing.

[0069] The invention is not limited to the embodiments described above. On the contrary, other variants of the invention can 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 embodiments can also be combined with each other in any desired manner without departing from the subject matter of the invention.

LIST OF REFERENCE NUMERALS

[0070] 2 motor vehicle [0071] 4 electric motor [0072] 6 power inverter [0073] 8 battery [0074] 10 battery cell [0075] 12 electrode assembly [0076] 14 anode [0077] 14a anode foil [0078] 14b first active material [0079] 14c contact [0080] 16 cathode apparatus [0081] 16a cathode [0082] 16b cathode foil [0083] 16c second active material [0084] 16d separator foil [0085] 16e contact [0086] 16f separator foil cutout [0087] 16g separator foil section [0088] 18 first face [0089] 20 cathode strip [0090] 22 cutting device [0091] 24 conveying device [0092] 26 rotary blade [0093] 28 area [0094] 30 second face [0095] 32 magazine [0096] 34 folding device [0097] 36 folded edge [0098] 38 contact face [0099] 40 laminating system [0100] 42 laser [0101] 44 conveying rollers [0102] 46 receptacle [0103] 48 conveying rollers [0104] 50 fused area [0105] 52 laminated area [0106] 54 stop [0107] L lengthwise direction of the strip [0108] Q crosswise direction of the strip