METHOD AND DEVICE FOR PRODUCING A COMPONENT FOR A BATTERY CELL AND SUCH A COMPONENT

Abstract

A method for manufacturing a component, the component having a multiplicity of cell foils for storing electrical energy that are stacked on top of one another and at least one contact plate, wherein the cell foils form a foil stack in a connection portion, and the foil stack is connected to the contact plate by at least one weld seam for the electrical contacting of the cell foils via the contact plate. Furthermore, a corresponding component and a device for manufacturing such a component are also specified.

Claims

1. A method for manufacturing a component, the component having a multiplicity of cell foils stacked on top of one another for storing electrical energy and at least one contact plate, wherein the cell foils form a foil stack in a connection portion, and the foil stack is connected to the contact plate by at least one weld seam for the electrical contacting of the cell foils via the contact plate, wherein the method for producing the at least one weld seam comprises at least the following steps: providing the cell foils, and arranging the foil stack with a stack height; providing the contact plate; compacting at least the foil stack by means of a compaction device; arranging the foil stack and the contact plate (relative to one another in a connecting position; generating a negative pressure at least in a connecting region of the foil stack and contact plate by means of a vacuum device; connecting the foil stack to the contact plate in the connecting region via the at least one weld seam produced using a laser welding process in the presence of the negative pressure.

2. The method as set forth in claim 1, wherein the vacuum device comprises at least one chamber in which at least the foil stack and the contact plate are arranged.

3. The method as set forth in claim 1, wherein the vacuum device comprises a first device part and a second device part, each of which forms a sealing surface with at least the foil stack or the contact plate, so that the vacuum device forms at least two chambers, in each of which at least one negative pressure is generated, and each chamber being formed at least partially at least by the foil stack or by the contact plate.

4. The method as set forth in claim 1, wherein the foil stack is formed by a plurality of foils arranged one on top of the other, wherein each foil has a first thickness, and the foils that are stacked on top of one another having the respective first thickness form the stack height, and wherein the first thickness is between 4 and 30 μm and each foil of the foil stack comprises at least 99.0% by weight of either copper or aluminum.

5. The method as set forth in claim 1, wherein the stack height is formed by at least ten foils stacked on top of one another.

6. The method as set forth in claim 1, wherein the contact plate in the connecting region has a second thickness of between 0.2 and 3 millimeters and comprises at least 99.0% by weight of either copper or aluminum.

7. The method as set forth in claim 1, wherein the contact plate has a coating which has a third thickness of no more than 2 μm and which comprises at least 99.0% by weight of nickel.

8. The method as set forth in claim 1, wherein the negative pressure in the connecting region is less than 30 mbar.

9. The method as set forth in claim 1, wherein the at least one weld seam is produced by a laser beam with a wavelength of between 405 and 575 nm.

10. A component, comprising: at least a multiplicity of cell foils for storing electrical energy that are stacked on top of one another, and at least one contact plate; wherein the cell foils form a foil stack in a connection portion, and the foil stack is connected to the contact plate by at least one weld seam in a butt joint or a lap joint; wherein the weld seam is produced by means of a method as set forth in claim 1; wherein the weld seam extends along a welding direction over a length and has a cross section transverse to the welding direction; and wherein the component has a first material thickness in the cross section and immediately adjacent to the weld seam, and all of the following conditions apply to at least 30% of the cross sections that exist along the weld seam: if the foil stack and the contact plate each comprise at least 99.0% copper: a minimum second material thickness of the weld seam is at least 70% of the first material thickness; a pore has a maximum diameter of 0.02 millimeters; and a porosity of the weld seam is no more than 20%; and if the foil stack and the contact plate each comprise at least 99.0% aluminum: a minimum second material thickness of the weld seam is at least 80% of the first material thickness; a pore has a maximum diameter of 0.04 millimeters; a porosity of the weld seam is no more than 20%; and at least 50% of the foils of the foil stack are attached to the weld seam.

11. The component as set forth in claim 10, wherein, if the foil stack and the contact plate each comprise at least 99.0% copper, at least one of the following conditions also applies: in the case of the lap joint, a connecting line between the foil stack and the contact plate is free of pores; the first material thickness is at least one millimeter, and a superelevation of a root of the weld seam is no more than 0.04 millimeters; the first material thickness is at least one millimeter, and a concavity of a root of the weld seam is no more than 0.1 millimeter; the first material thickness is at least one millimeter, and a superelevation of a cover pass of the weld seam is no more than 0.02 millimeters; the first material thickness is at least one millimeter, and a concavity of a cover pass of the weld seam is no more than 0.06 millimeters; the weld seam is at least free of cracks or edge notches or root concavities; and at least 50% of the foils of the foil stack are attached to the weld seam.

12. The component as set forth in claim 10, wherein if the foil stack and the contact plate each comprise at least 99.0% aluminum, at least one of the following conditions also applies: in the case of the lap joint, a connecting line between the foil stack and the contact plate is free of pores; the first material thickness is at least one millimeter, and a superelevation of a root of the weld seam is no more than 0.07 millimeters; the first material thickness is at least one millimeter, and a concavity of a root of the weld seam is no more than 0.05 millimeter; the first material thickness is at least one millimeter, and a superelevation of a cover pass of the weld seam is no more than 0.02 millimeters; the first material thickness is at least one millimeter, and a concavity of a cover pass of the weld seam is no more than 0.02 millimeters; and the weld seam is at least free of cracks or edge notches or root concavities.

13. A device for manufacturing a component, the component having a multiplicity of cell foils for storing electrical energy that are stacked on top of one another and at least one contact plate, wherein the cell foils form a foil stack in a connection portion, and the foil stack is connected to the contact plate by at least one weld seam for the electrical contacting of the cell foils via the contact plate; wherein the device is appropriately designed for carrying out the method as set forth in claim 1 and, for the purpose of producing the at least one weld seam, comprises at least one compaction device for compacting at least the foil stack, one vacuum device for generating a negative pressure at least in a connecting region of the foil stack and contact plate, and one laser device for connecting the foil stack to the contact plate in the connecting region via at least one weld seam produced using a laser welding process in the presence of the negative pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The invention and the technical environment will be explained in greater detail with reference to the enclosed figures. It should be noted that the invention is not intended to be limited by the specified embodiments. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the features explained in the figures and to combine them with other components and insights from the present description. In particular, it should be pointed out that the figures and, in particular, the illustrated proportions are only schematic. In the drawing: [0103] FIG. 1 shows a cross section through a weld seam that was produced by a known method, in section; [0104] FIG. 2 shows a cross section through another weld seam that was produced by a known method, in section; [0105] FIG. 3 shows a first design variant of a device with a component in a plan view according to steps e) and f); [0106] FIG. 4 shows the device according to FIG. 3 according to step c) in a side view; [0107] FIG. 5 shows the device according to FIG. 3 according to steps e) and f) in a side view; [0108] FIG. 6 shows a second embodiment of a device according to steps e) and f) in a side view; [0109] FIG. 7 shows a cross section through a weld seam produced by the described method, in section; and [0110] FIG. 8 shows a cross section through another weld seam that was produced by the described method, in section.

DETAILED DESCRIPTION OF THE INVENTION

[0111] FIG. 1 shows a cross section 24 through a weld seam 6 that was produced by a known method, in section. The component 1 comprises a contact plate 3 with a second thickness 19 and a foil stack 5, which form a lap joint. The foil stack 5 forms a top side and is oriented toward the beam source. The weld seam 6 comprises large pores 27, high porosity, and a pronounced concavity 30 of the root of the weld seam 6. The second material thickness 26 is substantially less than the first material thickness 25.

[0112] The first material thickness 25 is only implied here, since the air or free spaces are to be deducted in determining the first material thickness.

[0113] The material of the foils 17 of the foil stack 5 and the material of the contact plate 3 each comprise at least 99.0% aluminum. Each of the foils 17 has a first thickness 18.

[0114] A coating 20 of the contact plate 3 with a third thickness 21 is only implied here.

[0115] FIG. 2 shows a cross section 24 through another weld seam 6 that was produced by a known method, in section. The component 1 comprises a contact plate 3 and a foil stack 5, which form a lap joint. The foil stack 5 forms a top side and is oriented toward the beam source. The weld seam 6 comprises large pores 27, a high level of porosity, and a pronounced concavity 30 of the root (on the bottom side of the component 1) and the cover pass (on the top side of the component 1) of the weld seam 6. The second material thickness 26 is substantially less than the first material thickness 25. Only a small number of the foils 2 are connected to the contact plate 3 via the weld seam 6.

[0116] The first material thickness 25 is only implied here, since the air or free spaces are to be deducted in determining the first material thickness.

[0117] The material of the foils 17 of the foil stack 5 and the material of the contact plate 3 each comprise at least 99.0% copper. Each of the foils 17 has a first thickness 18.

[0118] FIG. 3 shows a first design variant of a device 31 with a component 1 in a plan view according to steps e) and f). FIG. 4 shows the device 31 of FIG. 3 according to step c) in a plan view. FIG. 5 shows the device 31 of FIG. 3 according to steps c) and f) in a side view. FIGS. 3 to 5 are described together below.

[0119] The component 1 has a multiplicity of cell foils 2 stacked on top of one another for storing electrical energy and at least one contact plate 3. The cell foils 2 form a foil stack 5 in a connection portion 4, and the foil stack 5 is connected to the contact plate 3 by a weld seam 6 for the electrical contacting of the cell foils 2 via the contact plate 3. The weld seam 6 is arranged adjacent to a sealed seam 33 of the battery cell by means of which the housing of the battery cell is sealed. The weld seam 6 is later arranged within the housing of the battery cell, so that the contact plate 3 extends from the weld seam 6 via the sealed seam 33 to the outside of the housing.

[0120] The device 31 is appropriately designed for carrying out the described method and comprises, for the purpose of producing the at least one weld seam 6, a compaction device 8 for compacting at least the foil stack 5, a vacuum device 11 for generating a negative pressure at least in a connecting region 10 of the foil stack 5 and contact plate 3, and a laser device 32 for connecting the foil stack 5 to the contact plate 3 in the connecting region 10 via at least one weld seam 6 produced using a laser welding process in the presence of the negative pressure.

[0121] The method serves to connect the contact plate 3 in an electrically conductive manner to the foil stack 5 so that the foil stack 5 can be connected to a circuit via the contact plate 3. The contact plate 3 forms an electrical connection of the component 1 or an electrical connection element of the component 1 for connecting the component 1 to external components or other components 1.

[0122] According to step a), the cell foils 2 are provided and the foil stack 5 is arranged with a stack height 7. The contact plate 3 is provided according to step b). The contact plate 3 and the foil stack 5 are arranged in a connecting position 9 (for a lap joint in this case) according to step d). According to step c), the foil stack 5 and the contact plate 3 are compacted by means of a compaction device 8 (see FIG. 4). In this connecting position 9, the foil stack 5 and the contact plate 3 are welded to one another in step f) by applying the laser beam 22 to the connecting region 10.

[0123] The compacting takes place by applying a pressure to the foil stack 5 and also to the contact plate 3, which is superposed with an ultrasonic excitation (FIG. 4). By means of the ultrasonic excitation, the individual components 2, 3, 5, 17 are shifted and moved at least relative to one another, so that air is successively displaced.

[0124] According to step e), a negative pressure is generated by a vacuum device 11 in a connection region 10 of the foil stack 5 and contact plate 3. The vacuum device 11 is used to remove air from the vicinity of the weld seam 6 that is to be produced (see FIGS. 5 and 6).

[0125] The vacuum device 11 comprises a first device part 14 and a second device part 15, each of which forms a sealing surface 16 with the foil stack 5 or the contact plate 3. The vacuum device 11 thus forms two chambers 12, 13, in each of which at least one negative pressure is generated. The first chamber 12 is formed by the first device part 14 and the foil stack 5, and the second chamber 13 is formed by the second device part 15 and the contact plate 3.

[0126] In this embodiment of the vacuum device 11, the regions between the foils 17 or between the foil stack 5 and the contact plate 3 are arranged outside of the vacuum device 11. As a result of the compacting of the foil stack 5 and the contact plate 3, however, air can be removed from these regions to such an extent that the quality of the weld joint is not impaired. The volume of the respective device part 14, 15 can be made very small, so that only a small amount of air has to be removed.

[0127] The respective sealing surface 16 is arranged completely on the foil stack 5 or on the contact plate 3 and thus comprises a surface portion that is designed to be as small as possible in consideration of the position and the length of the weld seam 6.

[0128] According to step f), the foil stack 5 is connected to the contact plate 3 in the connecting region 10 via a weld seam 6 that is produced using a laser welding process in the presence of the negative pressure. In particular, the weld seam 6 has a length along a welding direction 23.

[0129] FIG. 6 shows a second design variant of a device 31 according to steps e) and f) in a side view. In contrast to the first design variant, the vacuum device 11 comprises only one chamber 12, in which the foil stack 5 and the contact plate 3 are arranged. By arranging the foil stack 5 and the contact plate 3 in the chamber 12, air can possibly also be removed from the regions between the foils 17 of the foil stack 5 or between the foil stack 5 and the contact plate 3. However, the volume of the chamber 12 is quite large, and large amounts of air have to be removed, possibly for each component 1.

[0130] FIG. 7 shows a cross section 24 through a weld seam 6 that was produced by the described method, in section.

[0131] The component 1 comprises a contact plate 3 with a second thickness 19 and a foil stack 5, which form a lap joint. The foil stack 5 forms a top side and is oriented toward the beam source (the laser device 32). The weld seam 6 has almost no pores 27 and hence a low porosity, a slight superelevation 29 of the root, and a slight concavity 30 of the cover pass of the weld seam 6. The second material thickness 26 is even greater than the first material thickness 25.

[0132] In the lap joint shown, the material of the weld seam 6 is non-porous along a shortest connecting line 28 through the weld seam 6 between the foil stack 5 and the contact plate 3 or along the dividing line between the foil stack 5 and the contact plate 3. All of the foils 17 of the foil stack 5 are connected to the weld seam 6. [0133] The weld seam 6 is free of cracks, edge notches, and root concavities.

[0134] The material of the foils 17 of the foil stack 5 and the material of the contact plate 3 each comprise at least 99.0% aluminum. Each of the foils 17 has a first thickness 18.

[0135] FIG. 8 shows a cross section 24 through another weld seam 6 that was produced by the described method, in section.

[0136] The component 1 comprises a contact plate 3 with a second thickness 19 and a foil stack 5, which form a lap joint. The foil stack 5 forms a top side and is oriented toward the beam source (the laser device 32). The weld seam 6 has only very small pores 27 and hence a low porosity, a slight concavity 30 of the root, and a slight concavity 30 of the cover pass of the weld seam 6. The second material thickness 26 is only slightly less than the first material thickness 25.

[0137] In the lap joint shown, the material of the weld seam 6 is non-porous along a shortest connecting line 28 through the weld seam 6 between the foil stack 5 and the contact plate 3 or along the dividing line between the foil stack 5 and the contact plate 3. All of the foils 17 of the foil stack 5 are connected to the weld seam 6.

[0138] The weld seam 6 is free of cracks, edge notches, and root concavities.

[0139] The material of the foils 17 of the foil stack 5 and the material of the contact plate 3 each comprise at least 99.0% aluminum. Each of the foils 17 has a first thickness 18.

LIST OF REFERENCE SYMBOLS

[0140] 1 component [0141] 2 cell foil [0142] 3 contact plate [0143] 4 connection portion [0144] 5 foil stack [0145] 6 weld seam [0146] 7 stack height [0147] 8 compaction device [0148] 9 connecting position [0149] 10 connecting region [0150] 11 vacuum device [0151] 12 first chamber [0152] 13 second chamber [0153] 14 first device part [0154] 15 second device part [0155] 16 sealing surface [0156] 17 foil [0157] 18 first thickness [0158] 19 second thickness [0159] 20 coating [0160] 21 third thickness [0161] 22 laser beam [0162] 23 welding direction [0163] 24 cross section [0164] 25 first material thickness [0165] 26 second material thickness [0166] 27 pore [0167] 28 connecting line [0168] 29 superelevation [0169] 30 concavity [0170] 31 device [0171] 32 laser device [0172] 33 sealed seam