Battery cell with anode connection arrangement and cathode connection arrangement and method for manufacturing the battery cell

Abstract

A battery cell (1) comprises an electrode stack (6) with alternately arranged anodes, separators, and cathodes, a housing (2) in which the electrode stack (6) is arranged, an anode terminal assembly (3, 3a), a cathode terminal assembly (3, 3b), wherein the anode terminal assembly (3, 3a) is arranged on a side of the battery cell (1) opposite the cathode terminal assembly (3, 3b), anode connector tabs (7, 7a) for electrically connecting the anodes to the anode terminal assembly (3, 3a), and cathode connector tabs (3, 3b) for electrically connecting the cathodes to the cathode terminal assembly (3, 3b), wherein a connection type by which the anode connector tabs (7, 7a) and the anode terminal assembly (3, 3a) are connected is a connection type other than the Connection type by means of which the cathode drain tabs (7, 7b) and the cathode connection arrangement (3, 3b) are connected, wherein the anode drain tabs (7,7a) are electrically connected to the anode connection arrangement (3, 3a) by means of a flexible lower tab (12) or by butterfly welding, and wherein the cathode discharge tabs (7, 7b) are electrically connected to the cathode connection arrangement (3, 3b) by means of a U-shaped element (10), by means of a flexible lower tab (12) or by butterfly welding.

Description

[0001] The invention relates to a battery cell with an anode connection arrangement and a cathode connection arrangement and a method for manufacturing the battery cell.

[0002] Battery cells, especially lithium-ion battery cells, are increasingly used in various applications such as electric vehicles, portable electronic devices, and stationary energy storage systems. A key challenge in battery cell design is ensuring a reliable and efficient electrical and mechanical connection between the electrodes and the cell terminals, through which the battery cell can be connected to an external circuit.

[0003] Known solutions for contacting the electrodes include U-shaped terminal arrangements, such as those disclosed in US 5,773,164 A. These terminals connect the electrode current collectors to the terminals in the battery cell lid. However, this solution does not take into account the different material properties of the active material (anode and cathode), which can affect the contact options.

[0004] WO 2023 / 031110 A1 discloses a method for assembling a secondary cell, wherein the cell comprises an electrode stack housed in a casing, and wherein the casing comprises a base body, a first end plate at a first open end of the base body, and a second end plate at a second open end of the base body. The first end plate of the cell includes a contact tab designed to provide electrical contact between an electrode of the electrode stack and the first terminal. The contact tab is formed by a separate element, such as a sub-tab, which may be electrically connected to the electrode tab and thus serves to extend the electrode tab to facilitate attachment to the end plate.

[0005] WO 2024189174 A1 relates to a method for manufacturing a battery cell with two battery terminals, comprising a first cell cover with a first battery terminal on a first side and comprising a second cell cover with a second battery terminal on a second side opposite the first side, wherein two cell stacks with anode layers and cathode layers are provided, wherein the cathode layers have cathode arresters and the anode layers have anode arresters, wherein the cell stacks are positioned such that their anode arresters face each other and, at least partially, rest on a collector on the rear side of the second cell cover, which is electrically connected to the second battery terminal, wherein the anode arresters are electrically connected to the collector of the second cell cover and the at least two cell stacks are joined together by bending and / or folding the anode arresters.wherein the stacked cell units are positioned in a cell casing, wherein the cathode arresters are electrically connected to a collector arranged on the rear of the first cell cover, which is electrically connected to the first battery terminal, wherein the cell casing is closed by the first cell cover.

[0006] The object of the present invention is to provide an improved battery cell that at least partially overcomes the aforementioned disadvantages.

[0007] This problem is solved by the battery cell according to claim 1 and the method according to claim 9.

[0008] Further advantageous embodiments of the invention will become apparent from the dependent claims, the drawings and the following description of preferred embodiments of the present invention.

[0009] According to a first aspect, a battery cell according to the invention comprises an electrode stack with alternately arranged anodes, separators, and cathodes, a housing in which the electrode stack is arranged, an anode connection arrangement, a cathode connection arrangement, wherein the anode connection arrangement is arranged on a side of the battery cell opposite the cathode connection arrangement, anode connectors for electrically connecting the anodes to the anode connection arrangement, and cathode connectors for electrically connecting the cathodes to the cathode connection arrangement, wherein a connection type by which the anode connectors and the anode connection arrangement are connected is a different connection type than the connection type by which the cathode connectors and the cathode connection arrangement are connected.wherein the anode discharge tabs are electrically connected to the anode connection assembly by means of a flexible lower tab or by butterfly welding, and wherein the cathode discharge tabs are electrically connected to the cathode connection assembly by means of a U-shaped element, by means of a flexible lower tab or by butterfly welding.

[0010] A battery cell, for example a lithium-ion battery cell, can be a prismatic battery cell. A prismatic battery cell comprises a rigid casing in which a stack of electrodes is arranged.

[0011] A battery cell comprises electrodes made of active material, at least an anode and a cathode, and a separator may be positioned between the electrodes. The separator prevents direct contact between the electrodes while simultaneously allowing ion flow within the cell.

[0012] The electrodes are designed as an electrode stack, with anodes, cathodes, and separators arranged alternately on top of each other. The electrode stack can be configured as a jelly roll or a jelly stack. The casing, for example, the housing, seals the electrode stack inside. This protects the battery cell from external influences and ensures its structural integrity.

[0013] The battery cell can comprise one (single stack) or several, for example two (double stack), electrode stacks. Consequently, the electrode stack according to the invention can be designed as a single stack or as multiple electrode stacks, for example as a double stack.

[0014] The anodes and cathodes in the electrode stack are electrically connected to their respective terminals via anode-terminal tabs and cathode-terminal tabs, which may be bundled together. Thus, the anodes are electrically connected to the anode terminals via anode-terminal tabs, and the cathodes are electrically connected to the cathode terminals via cathode-terminal tabs.

[0015] There are various connection methods by which the conductor tabs can be attached to the respective connection assembly. These connection methods include a connection using a flexible bottom tab, a U-shaped element, or butterfly welding.

[0016] The connection type by which the anode drain tabs and the anode connection assembly are connected is a different connection type than the connection type by which the cathode drain tabs and the cathode connection assembly are connected.

[0017] This means that in a properly designed battery cell, one but not the same of the three connection types mentioned above is used on both the cathode and anode sides to connect the respective drain tabs to the respective terminal arrangement.

[0018] This ensures that the type of connection is optimally matched to the active material, thereby not only increasing the efficiency and effectiveness of the manufacturing process, but also guaranteeing improved adaptation to the specific requirements of the respective electrode.

[0019] For example, according to one embodiment, the flexible lower tab can be used on the anode side to connect the anode drain tabs to the anode connection assembly, and on the cathode side, the U-shaped element can be used to connect the cathode drain tabs to the cathode connection assembly.

[0020] Alternatively, the flexible bottom tab can be used on the anode side and butterfly welding can be used on the cathode side to connect the cathode drain tabs to the cathode connection assembly.

[0021] Alternatively, butterfly welding can be used on the anode side and the flexible bottom tab on the cathode side.

[0022] The embodiment in which the flexible bottom flap is used on the anode side and butterfly welding on the cathode side enables a higher volume energy density (VED) of the battery cell compared to the other two embodiments, since the distance between the lid and the electrode stack is minimized.

[0023] According to some embodiments, the flexible bottom tab, by means of which the anode leakage tabs are electrically connected to the anode terminal assembly or the cathode leakage tabs are electrically connected to the cathode terminal assembly, comprises several layers, for example, 2, 3, 4, 5, 6, 7, or 8 layers. The multiple layers can be joined together, for example, in a preceding welding step, using methods such as ultrasonic welding, laser beam welding, cold welding, or resistance welding, or by crimping, gluing, soldering, etc. The connection areas of the flexible bottom tab can also serve as welding points for joining the multiple layers of the bottom tab. The flexible bottom tab can be 0.6 to 1.2 mm thick, for example, 8 mm thick, when used on the anode side; accordingly, each layer can be 0.1 to 0.3 mm thick.

[0024] For example, with a total thickness of 0.75 or 0.8 mm, it is possible - with four layers, each layer should be 0.2 mm thick, - with five layers, each layer should be 0.15 mm thick, and - with eight layers, each layer should be 0.1 mm thick

[0025] When used on the cathode side, the flexible bottom tab can have a greater overall thickness; for example, it can be twice as thick or two-thirds thicker than when used on the anode side. This is because cathodes are generally thicker than anodes, for example, twice as thick or two-thirds thicker.

[0026] The flexible bottom flap can be 20 to 40 mm long, for example 28 mm, and 35 to 50 mm wide, for example 40 mm.

[0027] According to some embodiments, the flexible bottom tab, by means of which the anode drain tabs are electrically connected to the anode terminal assembly or the cathode drain tabs are electrically connected to the cathode terminal assembly, comprises two connection areas at two opposite ends of the flexible bottom tab and a bending area between the ends, wherein the anode drain tabs or the cathode drain tabs are arranged at one of the connection areas of the flexible bottom tab.

[0028] The conductor tabs can be welded to the connection area, e.g., by ultrasonic welding, laser beam welding, cold welding, or resistance welding, or electrically conductively attached by crimping, gluing, soldering, etc. For example, the connection area can be designed as a single weld point or a weld area with multiple weld points.

[0029] The other connection area of ​​the two connection areas can be used to contact the terminal assembly. Thus, the flexible lower tab can electrically connect to the conductor tabs via the first connection area and to the terminal assembly via the second connection area.

[0030] The bottom tab can be welded to the connection assembly, e.g., by ultrasonic welding, laser beam welding, cold welding, or resistance welding, or electrically attached by crimping, gluing, soldering, etc. For example, the connection area can be designed as a single weld point or a weld area with multiple weld points.

[0031] The flexible lower tab, by means of which the anode drain tabs are electrically connected to the anode connection assembly, may include copper, for example be made of copper.

[0032] The flexible lower tab by which the cathode arrester tabs are electrically connected to the cathode connection assembly can include aluminium, for example, be made of aluminium.

[0033] According to some embodiments, the battery cell further comprises two covers, designed as an anode-side cover and an opposing cathode-side cover for closing the housing. The anode terminal assembly can be designed as part of an anode-side cover that closes the housing from a first side, and the cathode terminal assembly can be designed as part of a cathode-side cover that closes the housing from a second side opposite the first.

[0034] The anode connection arrangement can thus be designed as an anode cover plate and the cathode connection arrangement can be designed as a cathode cover plate.

[0035] When the flexible bottom tab is used as a connection type, a connection area of ​​the flexible bottom tab can be electrically conductive, e.g., welded, to the cover, for example, to a rivet of the connection assembly located on the cover. If the flexible bottom tab is used on the anode-side cover with the anode connection assembly, the rivet of the cover can be made of copper. If the flexible bottom tab is used on the cathode-side cover with the cathode connection assembly, the rivet of the cover can be made of aluminum.

[0036] The bottom flap is flexible and can therefore serve as a film hinge, for example when closing a battery cell cover.

[0037] Butterfly welding involves dividing the conductor tabs into different welding areas, for example, two adjacent ones, creating the characteristic butterfly shape. The conductor tabs can be welded to the respective welding area using methods such as ultrasonic welding, laser beam welding, cold welding, or resistance welding. For instance, the welding area can be a single weld point or a weld area with multiple weld points.

[0038] Butterfly welding can therefore involve the anode drain tabs or the cathode drain tabs being welded to different parts of the anode connection assembly or the cathode connection assembly, for example on the cover.

[0039] The battery cell can comprise two electrode stacks. Therefore, the division of the anode or cathode leakage tabs for butterfly welding can involve a division of the anode or cathode leakage tabs according to electrode stack. Consequently, the leakage tabs (anode or cathode leakage tabs, depending on the application) of one electrode stack can be bundled together and welded to a first welding area of ​​the terminal assembly (anode or cathode terminal assembly, depending on the application), and the leakage tabs of the second electrode stack can be bundled together and welded to a second welding area of ​​the terminal assembly.

[0040] Some embodiments relate to a method for manufacturing the battery cell according to the invention, as described above or below. The battery cell can thus include any feature listed in this description.

[0041] According to some embodiments, the procedure comprises the following steps: - Connecting the anode drain tabs to the anode connection assembly; - Connecting the cathode drain tabs to the cathode connection assembly; - Inserting the electrode stack into the housing; and - Closing the case by folding down at least one lid.

[0042] The steps can be performed in any order. For example, inserting the electrode stack into the housing can also be an intermediate step in the step of connecting the anode arrester tabs to the anode terminal assembly or in the step of connecting the cathode arrester tabs to the cathode terminal assembly. For example, if the flexible bottom tab is used as the connection type, the flexible bottom tab can first be attached to the respective arrester tab outside the housing, and then, for example after the electrode stack has been inserted into the housing, the flexible bottom tab can be attached to the respective terminal assembly.

[0043] Connecting the anode drain tabs to the anode connection assembly may involve welding the anode drain tabs to the flexible bottom tab and welding the flexible bottom tab to the opened anode-side cover.

[0044] Connecting the cathode drain tabs to the cathode connection assembly can involve welding the cathode drain tabs to the U-shaped element or butterfly welding them to the cathode connection assembly.

[0045] Closing the housing by folding down at least one cover can include folding down the anode-side cover with the welded-on flexible bottom flap.

[0046] Therefore, if a flexible bottom tab is used on the anode side and the U-shaped element is used on the cathode side, the following steps can be carried out: The cathode arrestor tabs can be welded to the U-shaped element, which can be part of the cathode-side cover. The electrode stack, which can be a single stack or multiple stacks, such as a double stack, is therefore first welded to the U-shaped element of the cathode-side cover outside the housing via the cathode arrestor tabs. This provides space, for example, for the laser beam to weld the cathode arrestor tabs to the arms of the U-shaped element.

[0047] Furthermore, one side of the lower tab is also welded to the anode discharge tabs. This can be done in any order, before or after welding on the cathode discharge tabs. This welding can also be done outside the housing.

[0048] The electrode stack, now attached to the U-shaped element of the cathode connection assembly via the cathode arrester tabs, can then be inserted into the housing. Since the U-shaped element can be part of the cover, the electrode stack can be positioned so that the housing is closed on one side by the cathode-side cover. For a secure seal, the cathode-side cover can be welded to the housing.

[0049] The anode-side cover can then be placed on the open end of the housing, and in the opened state, the lower tab, which has so far only been welded to the anode discharge tabs, can be welded to the anode connection arrangement, for example on the anode-side cover (e.g. a rivet arranged on the cover, which may be made of copper).

[0050] Since the anode-side cover is in the open position, the laser, for example, has easy access to the connection area for welding the bottom flap. The anode-side cover can then be closed to seal the housing. Because the bottom flap is flexible, the cover can be easily closed with the bottom flap. After closing, the anode-side cover can also be welded to the housing for a secure seal.

[0051] The lower tab on the anode side thus serves as a bridge between the bundled anode discharge tabs and the anode cover plate. Since the anode discharge tabs can be thinner, for example by two-thirds, than the cathode discharge tabs, they are easier to handle during the bending process, which allows the cover to close smoothly.

[0052] In contrast, the U-shape of the U-shaped element on the cathode side shortens the connection between the cathode terminal assembly and the electrode stack. This reduces tolerances because bending the cathode leakage tabs is not required. Since the bundle of cathode leakage tabs can be larger than the bundle of anode leakage tabs, for example due to thicker films, the U-shape with its two welding contact areas is the contact-optimized choice on the cathode side.

[0053] If, instead, a flexible bottom tab is used on the anode side and butterfly welding is used on the cathode side, the following steps can be performed: The cathode arrestor tabs can be welded to the cathode connection assembly, which is designed, for example, as a cathode cover plate. This takes place outside the housing. The electrode stacks can initially be positioned flat next to the cathode connection assembly, such as the cathode cover plate, for welding. In the case of a double stack, for example, the stacks can be arranged on opposite sides of the connection assembly. This gives the laser, for example, more space for welding. The cathode arrestor tabs are then in a bent position. Subsequently, the electrode stacks with the cathode arrestor tabs can be positioned upright, for example, rotated at a 90° angle, so that the cathode arrestor tabs are bent back into their original shape.

[0054] Furthermore, one side of the lower tab is also welded to the anode discharge tabs. This can be done in any order, for example, before or after welding on the cathode discharge tabs. This can also be done outside the housing.

[0055] The electrode stack, which may be welded to the cathode-side cover via the cathode-side drain tabs, can then be inserted into the housing. The electrode stack can be positioned so that the housing is closed on one side by the cathode cover plate. For a secure seal, the cathode-side cover can be welded to the housing.

[0056] Butterfly welding on the cathode side reduces the required length of the cathode leakage tabs. The bundle of cathode leakage tabs can be divided into two parts, making them easier to bend during the electrode stack erection step. This also facilitates closing the housing from one side by inserting the electrode stack into the housing, which is then sealed on one side by the cathode-side cover. Since the films on the cathode side can be thicker, for example, two-thirds thicker, than those on the anode side, this configuration helps to manage the more demanding behavior of the cathode leakage tabs during cover closing.

[0057] After inserting the electrode stack into the housing, the anode-side cover with the anode connection assembly at the open end of the housing can be attached. With the cover open, the flexible lower tab, which was previously only welded to the anode terminals, can be welded to the anode connection assembly, for example, to the anode-side cover (e.g., to a rivet located on the cover, which may be made of copper).

[0058] Since the anode-side cover is in the open position, the laser beam, for example, has easy access to the connection area for welding the bottom flap. The anode-side cover is then closed to seal the housing. Because the bottom flap is flexible, the cover can be easily closed with the bottom flap. After closing, the anode-side cover can also be welded to the housing for a secure seal.

[0059] If, instead, a flexible bottom tab is used on the anode side and butterfly welding on the cathode side, the steps above can be performed on the opposite side. Thus, all the cathode-side steps described in the previous example are now performed on the anode side and vice versa, with the rivet on the cathode-side cover potentially being made of aluminum instead of copper.

[0060] Accordingly, in some embodiments, connecting the anode discharge tabs to the anode connection assembly may include butterfly welding of the anode discharge tabs to the anode connection assembly, and connecting the cathode discharge tabs to the cathode connection assembly may include welding the cathode discharge tabs to the flexible lower tab and welding the flexible lower tab to the opened cathode-side cover, wherein closing the housing by folding down the at least one cover may include folding down the cathode-side cover with the welded-on flexible lower tab. Furthermore, closing the cover may also include welding it to the housing.

[0061] Overall, the embodiments according to the invention are thus adapted to the material properties of the respective active material in such a way that the contacting is optimized and therefore more efficient, and the volume energy density, and consequently the performance and efficiency of the battery cell, are also optimized. Furthermore, the manufacturing process is also more efficient and effective due to the optimized use of the connection types on the anode and cathode sides.

[0062] Exemplary embodiments of the invention are now described by way of example and with reference to the accompanying drawing, in which: Fig. Figure 1 schematically shows a sectional view of a connection arrangement of a battery cell, wherein, according to one embodiment, conductor tabs are attached to the connection arrangement via a U-shaped element; Fig. Figure 2 schematically shows a section of a perspective view of an opened battery cell, in which, according to an embodiment, conductor tabs are attached to the connection arrangement via a flexible lower tab; Fig. Figure 3 schematically shows a section of a sectional view of a battery cell in which, according to an exemplary embodiment, conductor tabs are attached to the connection arrangement by means of butterfly welding; Fig. Figure 4 schematically shows a sectional view of a battery cell according to an embodiment, in which anode drain tabs are attached to the anode terminal assembly by means of a flexible lower tab and cathode drain tabs are attached to the cathode terminal assembly by means of a U-shaped element; Fig. Figure 5 schematically shows a sectional view of a battery cell according to an embodiment, in which anode drain tabs are attached to the anode terminal assembly by means of a flexible lower tab and cathode drain tabs are attached to the cathode terminal assembly by means of butterfly welding; Fig. Figure 6 schematically shows a sectional view of a battery cell according to an embodiment, in which anode drain tabs are attached to the anode terminal assembly by means of butterfly welding and cathode drain tabs are attached to the cathode terminal assembly by means of a bottom tab; Fig. Figure 7a schematically shows a side view of a flexible bottom flap according to the embodiments from Fig. 2, Fig. 4, Fig. 5 and Fig. 6 shows; Fig. 7b schematic a top view of the bottom flap made of Fig. 7a shows; Fig. 8 a diagram of a manufacturing process of the battery cell of Fig. 4 according to an exemplary embodiment; Fig. 9 a diagram of a manufacturing process of the battery cell of Fig. 5 according to an exemplary embodiment; Fig. 10 a diagram of a manufacturing process of the battery cell of the Fig. 6 according to an exemplary embodiment; Fig. Figure 11 schematically shows butterfly welding according to an exemplary embodiment; Fig. 12a schematically shows a side view of a battery cell according to an exemplary embodiment; and Fig. Figure 12b shows a schematic perspective view of a battery cell according to an exemplary embodiment.

[0063] Fig. Figure 1 shows a schematic sectional view of a connection arrangement of a battery cell, wherein, according to one embodiment, drain tabs are attached to the connection arrangement via a U-shaped element.

[0064] In Fig. Figure 1 is only a partial view of one end of battery cell 1 (e.g., 1, from Fig. 12a and Fig. 12b) shown in sectional view, where the housing (e.g. 4, Fig. 2, Fig. 7a and Fig. 7b) is not shown for the sake of clarity.

[0065] Battery cell 1 comprises a housing (not visible) in which two electrode stacks 6 are arranged. The active material, for example the cathodes, of the electrode stacks 6 are electrically connected to terminals 7 via a connection arrangement 3. The housing is closed on one side by a cover 4, on which a connection arrangement 3 for connecting the battery cell 1 to an external circuit is arranged. The connection arrangement 3 is integrated into the cover 4. A U-shaped element 10 of the connection arrangement 3 is arranged on the inside of the cover 4. The U-shaped element 10 comprises two arms whose ends point towards the electrode stacks 6. The outer surfaces of the two arms are designed as contact areas 10a to which terminals 7 are electrically connected. Thus, in Fig. 1 the conductor flags 7 are electrically conductively attached to the connection arrangement 3 via the connection type of the U-shaped element 10.

[0066] Fig. Figure 2 shows a schematic section of a perspective view of an opened battery cell, in which, according to one embodiment, conductor tabs are attached to the connection arrangement via a flexible lower tab.

[0067] In Fig. 2 is only a partial view of one end of battery cell 1 (e.g. 1, from Fig. 12a and Fig. Figure 12b). Battery cell 1 is shown in the open state for better illustration.

[0068] Battery cell 1 comprises housing 2 in which two electrode stacks 6 are arranged. The electrodes, for example the anodes or the cathodes, of the electrode stack 6 are electrically connected via terminal tabs 7 with connection arrangement 3.

[0069] Housing 2 can be closed on one side with lid 4, with lid 4 in Fig. 2 is shown in the open position. The lid 4 incorporates connection arrangement 3 for connecting the battery cell 1 to an external circuit. Connection arrangement 3 includes, for example, rivet 14 on the inside of the lid 4.

[0070] The lower tab 12 connects the drain tabs 7 to the connection assembly 3. The lower tab 12 comprises a connection area 12a, to which the drain tabs are attached, and a connection area 12b, to which the connection assembly 3, namely the rivet 14 of the connection assembly 3 located on the inside of the cover 4, is attached. The drain tabs 7 are attached to the upper side of the lower tab 12 in connection area 12a, and the lower tab 12 is attached to the rivet 14 on the underside in connection area 12b.

[0071] Furthermore, the lower flap 12 includes a bending area between the two connection areas 12a and 12b. The lower flap 3 is designed such that it can be bent in the bending area when the lid 4 is closed. The flexible lower flap 12 thus serves as a film hinge to close the lid 4. Consequently, in Fig. 2 the conductor flags 7 are electrically conductively attached to the connection arrangement 3 via the connection type of the lower tab 12.

[0072] Fig. Figure 3 shows a schematic section of a sectional view of a battery cell in which, according to an exemplary embodiment, drain tabs are attached to the connection arrangement by means of butterfly welding.

[0073] In Fig. Figure 3 is only a partial view of one end of battery cell 1 (e.g., 1, from Fig. 12a and Fig. 12b) shown.

[0074] Battery cell 1 comprises housing 2 in which two electrode stacks 6 are arranged. The active material, for example the anodes or the cathodes, of the electrode stacks 6 are electrically connected via terminal tabs 7 with connection arrangement 3.

[0075] Housing 2 is closed on one side by cover 4, the cover 4 being equipped with a connection assembly 3 for connecting the battery cell 1 to an external circuit. The connection assembly 3 is integrated into the cover 4.

[0076] The discharge tabs 7 are attached to the connection assembly 3 by means of butterfly welding, specifically to two welding areas of the connection assembly 3 via welds 13. Two welding areas with welds 13, arranged side by side (in one plane), are located on the inside of the cover 4. The discharge tabs 7 are divided according to the welding areas. A first part of the discharge tabs 7, for example, the discharge tabs of the first electrode stack 6, are welded to one welding area with weld 13, and the second part of the discharge tabs 7, for example, the discharge tabs 7 of the second electrode stack 6, are welded to the other welding area with weld 13. The division of the discharge tabs 7 into two parts creates the characteristic butterfly shape of butterfly welding.

[0077] Fig. Figure 4 shows a schematic sectional view of a battery cell according to an exemplary embodiment, in which anode leakage tabs are attached to the anode terminal assembly by means of a lower tab and cathode leakage tabs are attached to the cathode terminal assembly by means of a U-shaped element. For clarity, the battery cell is shown in a partial view with interruptions, which is indicated by the dashed lines.

[0078] Battery cell 1 of the Fig. 4 comprises a housing 2 in which two electrode stacks 6 are arranged. Each electrode stack 6 comprises anodes, cathodes, and separators stacked one above the other in an alternating arrangement. Housing 2 is closed longitudinally on both sides by a cover 4 (see figure). Fig. 12a and Fig. 12b).

[0079] At the left end, cover 4 incorporates anode connection assembly 3a (anode cover plate), and at the right end, cover 4 incorporates cathode connection assembly 3b (cathode cover plate). Anode and cathode connection assemblies 3a and 3b are used to connect battery cell 1 to an external circuit.

[0080] The anodes (not visible) of the two electrode stacks 6 are connected to the anode terminal assembly 3a via anode drain tabs 7a. The cathodes (not visible) of the two electrode stacks 6 are connected on the opposite side to the cathode terminal assembly 3b via cathode drain tabs 7b.

[0081] The anode discharge tabs 7a are electrically connected to the anode connection assembly 3a by means of a flexible lower tab 12. The anode discharge tabs 7a are attached (e.g., welded) to the connection area 12a of the lower tab 12, and the lower tab 12 is attached (e.g., welded) to the rivet 14 of the anode connection assembly 3b on the cover 4 at connection area 12b. In the bending area of ​​the lower tab 12, the lower tab 12 is bent at two points so that the cover 4 can close the housing 2. Thus, the flexible lower tab 12 acts as a film hinge to close the cover 4.

[0082] The bottom tab 12 can, for example, be made of copper and be multi-layered, as in Fig. 7a and Fig. 7b shown, be trained. In Fig. Figure 4 shows the drain tabs 7a attached to both sides of the connection area 12a of the lower tab 12. Alternatively, all drain tabs 7a can also be attached as shown in Fig. 2 described and shown on one side of the connection area 12a of the lower flap 12, for example the top of the connection area 12a.

[0083] The cathode discharge tabs 7b are electrically connected to the anode connection assembly 3b by means of a U-shaped element 10. The connection method using the U-shaped element 10 is as shown in Fig. 1 described and shown. Consequently, cathode arrester tabs 7b are welded to the two contact areas 10a of the U-shaped element 10. The cathode arrester tabs 7b can be distributed across the two contact areas 10 according to the electrode stack 6.

[0084] The U-shaped element 10 on the cathode side shortens the connection of the cathode leakage tabs 7b and minimizes the distance between the electrode stack 6 and the cover 4, thereby reducing tolerances since no bending of the leakage tabs is required. Additionally, the bundle of cathode leakage tabs is larger than the bundle of anode leakage tabs due to thicker foils. Thus, the U-shape of the element, with the cathode leakage tabs distributed across the two contact areas 10a, facilitates the connection on the cathode side.

[0085] The lower tab 12 on the anode side serves as a bridge between the compacted discharge tabs 7a and the anode cover plate 3a, 4. Furthermore, the flexible lower tab 12 acts as a film hinge to close the cover 4. Since the anode discharge tabs 7a are thinner than the cathode discharge tabs 7b, they are easier to handle during the bending process, which allows for smooth closing of the cover 4.

[0086] Fig. Figure 5 shows a schematic sectional view of a battery cell according to an exemplary embodiment, in which anode leakage tabs are attached to the anode terminal assembly by means of a bottom tab and cathode leakage tabs are attached to the cathode terminal assembly by means of butterfly welding. For clarity, the battery cell is shown in a partial view with interruptions, which is indicated by the dashed lines.

[0087] Battery cell 1 of the Fig. 5 comprises a housing 2 in which two electrode stacks 6 are arranged. Each electrode stack 6 comprises anodes, cathodes, and separators stacked one above the other in an alternating arrangement. Housing 2 is closed longitudinally on both sides by a cover 4 (see figure). Fig. 12a and Fig. 12b).

[0088] At the left end of cover 4, an anode connection assembly 3a (anode cover plate) is integrated, and at the right end of cover 4, a cathode connection assembly 3b (cathode cover plate) is integrated. Anode and cathode connection assemblies 3a and 3b serve to connect battery cell 1 to an external circuit.

[0089] The anodes (not visible) of the two electrode stacks 6 are connected to the anode terminal assembly 3a via anode drain tabs 7a. The cathodes (not visible) of the two electrode stacks 6 are connected on the opposite side to the cathode terminal assembly 3b via cathode drain tabs 7b.

[0090] The anode discharge tabs 7a are electrically connected to the anode connection assembly 3a by means of a lower tab 12. The connection method using the lower tab 12 is as shown in Fig. As described and shown in Figure 4, anode discharge tabs 7a are attached (e.g., welded) to the connection area 12a of the lower tab 12, and the lower tab 12 is attached (e.g., welded) to the rivet 14 of the anode connection assembly 3b on the cover 4 in the connection area 12b. In the bending area of ​​the lower tab 12, the lower tab 12 is bent at two points so that the cover 4 can close the housing 2. Thus, the flexible lower tab 12 serves as a film hinge to close the cover 4. The lower tab 12 can, for example, be made of copper and be multi-layered, as shown in Figure 4. Fig. 7a and Fig. 7b shown to be trained.

[0091] In Fig. Figure 5 shows the drain tabs 7a attached to both sides of the connection area 12a of the lower tab 12. Alternatively, all drain tabs 7a can also be attached as shown in Fig. 2 described and shown on one side of the connection area 12a of the lower flap 12, for example the top of the connection area 12a.

[0092] The cathode discharge tabs 7b are electrically connected to the cathode connection assembly 3b by means of butterfly welding. The butterfly welding connection is carried out as shown in Fig. 3 described and shown. Consequently, cathode arrester tabs 7b are welded to the two welding areas (see welds 13) of the cathode connection arrangement 3b. The cathode arrester tabs 7b can be divided between the two welding areas according to the electrode stack 6, creating the characteristic butterfly shape.

[0093] The butterfly welding on the cathode side reduces the required length of the cathode drain tabs 7b and facilitates the closing of the lid 4 by dividing the bundle of cathode drain tabs into two parts that are easier to bend during the lid closing process. Since the foils on the cathode side are thicker than those on the anode side, this configuration helps to manage the more demanding behavior of the cathode drain tabs during lid closing.

[0094] Similar to the configuration from Fig. 4 The lower tab 12 connects the compacted anode discharge tabs 7a to the anode cover plate 3a, 4 on the anode side, with the thinner anode discharge tabs 7a simplifying the bending process and ensuring easy closing of the cover 4. Thus, the flexible lower tab 12 serves as a film hinge to close the cover 4.

[0095] Furthermore, the distance between the cathode cover plate and the electrode stack is minimized, for example less than in the embodiment of the Fig. 4. Furthermore, the distance between the anode cover plate and the electrode stack is also minimized. This ensures an optimized volume energy density of the battery cell.

[0096] Fig. Figure 6 shows a schematic sectional view of a battery cell according to an exemplary embodiment, in which anode leakage tabs are attached to the anode terminal assembly by butterfly welding and cathode leakage tabs are attached to the cathode terminal assembly by means of a bottom tab. For clarity, the battery cell is shown in a partial view with interruptions, which is indicated by the dashed lines.

[0097] Battery cell 1 of the Fig. 6 comprises a housing 2 in which two electrode stacks 6 are arranged. Each electrode stack 6 comprises anodes, cathodes, and separators stacked one above the other in an alternating arrangement. Housing 2 is closed longitudinally on both sides by a cover 4 (see figure). Fig. 12a and Fig. 12b).

[0098] At the left end of cover 4, an anode connection assembly 3a (anode cover plate) is integrated, and at the right end of cover 4, a cathode connection assembly 3b (cathode cover plate) is integrated. Anode and cathode connection assemblies 3a and 3b serve to connect battery cell 1 to an external circuit.

[0099] The anodes (not visible) of the two electrode stacks 6 are connected to the anode terminal assembly 3a via anode drain tabs 7a. The cathodes (not visible) of the two electrode stacks 6 are connected on the opposite side to the cathode terminal assembly 3b via cathode drain tabs 7b.

[0100] The anode discharge tabs 7a are electrically connected to the anode connection assembly 3a by means of butterfly welding. The butterfly welding connection is carried out as shown in Fig. 3 described and shown. Consequently, anode discharge tabs 7a are welded to the two weld areas (see welds 13) of the anode connection assembly 3a. The anode discharge tabs 7a can be divided between the two weld areas according to the electrode stack 6, creating the characteristic butterfly shape.

[0101] The cathode discharge tabs 7b are electrically connected to the cathode connection assembly 3b by means of the lower tab 12. The cathode discharge tabs 7b are attached (e.g., welded) to the connection area 12a of the lower tab 12, and the lower tab 12 is attached (e.g., welded) to the rivet 14 of the cathode connection assembly 3b on the cover 4 in the connection area 12b. In the bending area of ​​the lower tab 12, the lower tab 12 is bent at two points so that the cover 4 can close the housing 2. Thus, the flexible lower tab 12 serves as a film hinge to close the cover 4. The lower tab 12 can, for example, be made of aluminum and be multi-layered, as in the following example: Fig. 7a and Fig. 7b shown to be trained.

[0102] In Fig. Figure 6 shows the drain tabs 7b attached to both sides of the connection area 12a of the lower tab 12. Alternatively, all drain tabs 7a can also be attached as shown in Fig. 2 described and shown on one side of the connection area 12a of the lower flap 12, for example the top of the connection area 12a.

[0103] Fig. Figure 7a shows a schematic side view of the lower tab as it is used in the battery cells according to the embodiments shown in Fig. 2, Fig. 4, Fig. 5 and Fig. 6 is used and Fig. Figure 7b shows a schematic top view of the bottom flap made of Fig. 7a.

[0104] The bottom plate 12 is made of four layers stacked on top of each other. When used on the anode side, the bottom plate 12 is made of copper, with each copper layer having a thickness of, for example, 0.2 mm, resulting in a total thickness of the bottom plate 0.8 mm. When used on the cathode side, thicker bottom plates and layers can be used, since the cathodes are twice as thick, or up to two-thirds thicker, than the anodes. Furthermore, when used on the cathode side, the bottom plate can be made of, for example, aluminum.

[0105] The total length (x-direction, Fig. 12a) The bottom tab is, for example, 28 mm and the width is, for example, 40 mm (z-direction, Fig. 12a). The lower tab 12 comprises two connection areas 12a and 12b at both ends. Each connection area is, for example, 6 mm long. Connection area 12a serves to attach the anode or cathode discharge tabs (depending on the application), and connection area 12b serves to attach them to the corresponding terminal assembly (3a or 3b) on the battery cell cover 4. Connection areas 12a and 12b can also serve to connect the four layers. Therefore, the four layers can be welded together in connection areas 12a and 12b.

[0106] The bending area of ​​the lower flap 12 is located between the connection areas 12a and 12b. This bending area makes it possible to bend the lower flap 12, for example at two points, so that the cover can close the housing of a battery cell, as shown in Fig. 2, Fig. 4, Fig. 5 and Fig. 6 described. The bottom flap 12 thus serves as a film hinge. The four-layer construction of the bottom flap 12 provides sufficient flexibility and stability to meet the mechanical requirements during the bending process and closing of the lid 4.

[0107] Fig. Figure 8 shows a diagram of a manufacturing process for the battery cell of the Fig. 4 according to an exemplary embodiment.

[0108] In step 21 of procedure 20, the cathode drain tabs (7b, Fig. 4) divided into two bundles, each to a contact area (10a, Fig. 4) of the U-shaped element (10, Fig. 4) the cathode cover plate (3a, 4, Fig. 4) welded on. Consequently, the first bundle of cathode arrester tabs of the first of two electrode stacks (6, Fig. 4) welded to one arm of the U-shaped element and the second bundle of cathode arrester tabs of the second of two electrode stacks (6, Fig. 4) is welded to the second arm of the U-shaped element.

[0109] In the next step 22, which can also be performed before step 21, the anode drain tabs (7a, Fig. 4) at the first of two connection areas (12a, Fig. 4) the flexible bottom flap (12, Fig. 4) welded on. Alternatively, step 22 can also be carried out after step 23, i.e., after insertion into the housing.

[0110] In the next step 23, the electrode stacks together with the welded cathode cover plate are placed into the housing (2, Fig. 4) inserted so that the cathode cover plate closes the housing from one side and the cathode cover plate is welded to the housing. Alternatively, step 23 can also be performed before step 22. Furthermore, the cathode cover plate can also be welded to the housing at a later time, for example at the end of procedure 20 (in or after step 25) together with the anode cover plate.

[0111] In step 24, the anode cover plate (3a, 4, Fig. 4) placed against the opposite open side of the housing and the bottom flap is attached to the connection area (12b, Fig. 4) to the rivet (14, Fig. 4) welded to the anode cover plate.

[0112] In step 25, the anode cover plate is folded down to close the housing on the anode side, and the anode cover plate is welded to the housing.

[0113] Fig. Figure 9 shows a diagram of a manufacturing process for the battery cell of the Fig. 5 according to an exemplary embodiment.

[0114] In step 31 of procedure 30, the cathode drain tabs (7b, Fig. 5) divided into two bundles, each attached to a welding area (see weld 13, Fig. 5) the cathode cover plate (3a, 4, Fig. 5) welded on. Consequently, the first bundle of cathode arrester tabs of the first of two electrode stacks (6, Fig. 5) welded to a first welding area of ​​the cathode cover plate and the second bundle of cathode arrester tabs of the second of two electrode stacks (6, Fig. 4) is welded to the second welding area of ​​the cathode cover plate. For this purpose of welding, the electrode stacks are laid flat next to the cathode cover plate (see e.g., Fig. 11).

[0115] In the next step 32, after the cathode arrester tabs have been welded on, the two electrode stacks are folded up so that the cathode cover plate is no longer next to, but above the two electrode stacks (see e.g., Fig. 11).

[0116] In the next step 33, the anode drain tabs (7a, Fig. 5) at the first of two connection areas (12a, Fig. 5) the flexible bottom flap (12, Fig. 5) welded on. Alternatively, step 33 can also be carried out after step 34, i.e., after insertion into the housing.

[0117] In the next step 34, the electrode stacks, including the welded-on cathode cover plate and welded-on bottom tab, are placed into the housing (2, Fig. 5) inserted so that the cathode cover plate closes the housing from one side and the cathode cover plate is welded to the housing. Alternatively, step 34 can also be performed before step 33. Furthermore, the cathode cover plate can also be welded to the housing at a later time, for example at the end of procedure 30 (in or after step 35) together with the anode cover plate.

[0118] In the next step 35, the anode cover plate (3a, 4, Fig. 5) placed against the opposite open side of the housing and the bottom flap is attached to the connection area (12b, Fig. 5) to the rivet (14, Fig. 5) welded to the anode cover plate.

[0119] In the next step 36, the anode cover plate is folded down to close the housing on the anode side and the anode cover plate is welded to the housing.

[0120] Fig. Figure 10 shows a diagram of a manufacturing process for the battery cell of the Fig. 6 according to an exemplary embodiment.

[0121] In step 41 of procedure 40, the anode drain tabs (7a, Fig. 6) divided into two bundles, each attached to a welding area (see weld 13, Fig. 6) the anode cover plate (3a, 4, Fig. 6) welded on. Consequently, the first bundle of anode discharge tabs of the first of two electrode stacks (6, Fig. 6) welded to a first welding area of ​​the anode cover plate and the second bundle of cathode arrester tabs of the second of two electrode stacks (6, Fig. 6) is welded to the second welding area of ​​the anode cover plate. For this purpose of welding, the electrode stacks are laid flat next to the anode cover plate (see e.g., Fig. 11).

[0122] In the next step 42, after the anode discharge tabs have been welded on, the two electrode stacks are folded up so that the anode cover plate is no longer next to, but above the two electrode stacks (see e.g., Fig. 11).

[0123] In the next step 43, the cathode drain tabs (7b, Fig. 6) at the first of two connection areas (12a, Fig. 6) the flexible bottom flap (12, Fig. 6) welded on. Alternatively, step 43 can also be carried out after step 44, i.e., after insertion into the housing.

[0124] In the next step 44, the electrode stacks, including the welded-on anode cover plate and welded-on bottom tab, are placed into the housing (2, Fig. 6) inserted so that the anode cover plate closes the housing from one side and the anode cover plate is welded to the housing. Alternatively, step 44 can also be performed before step 43. Furthermore, the anode cover plate can also be welded to the housing together with the cathode cover plate at a later time, for example at the end of procedure 40 (in or after step 46).

[0125] In the next step 45, the cathode cover plate (3b, 4, Fig. 6) placed against the opposite open side of the housing and the bottom flap is attached to the connection area (12b, Fig. 6) to the rivet (14, Fig. 6) welded to the cathode cover plate.

[0126] In the next step 46, the cathode cover plate is folded over to close the housing on the cathode side, and the cathode cover plate is welded to the housing.

[0127] Fig. Figure 11 schematically shows butterfly welding according to one embodiment.

[0128] The representation in Fig. 11 corresponds to process steps 31 and 32 regarding the butterfly welding of the cathode drain tabs to the cathode cover plate made of Fig. 9 or process steps 41 and 42 regarding the butterfly welding of the anode drain tabs to the anode cover plate Fig. 10.

[0129] As a first step (e.g., 31, Fig. 9 or Fig. 41, Fig. 10) The two electrode stacks 6 are placed flat (in a horizontal orientation) on both sides next to the cover 4 with connection arrangement 3. Since the electrode stacks 6 initially lie in two separate stacks on the left and right of the cover 4, the current collector tabs 7 (e.g. 7a, Fig. 6 or Fig. 7b, Fig. 5) The two electrode stacks 6 are divided into two separate bundles. One bundle per electrode stack 6 is welded to the connection arrangement 3 on the inside of the cover 4 via weld 13 in each welding area. Consequently, the first bundle of conductive tabs 7 of the first of the two electrode stacks 6 (left) is welded to a first welding area (see weld 13, left), and the second bundle of conductive tabs 7 of the second of the two electrode stacks 6 (right) is welded to the second welding area (see weld 13, right).

[0130] In a next step (e.g., 32, Fig. 9 or Fig. 42, Fig. 10) The two electrode stacks 6 are tilted up by 90° so that a double stack is formed, which is arranged longitudinally above the cover 4.

[0131] Fig. 12a shows a side view of a battery cell according to one embodiment and Fig. Figure 12b shows a perspective view of the battery cell. Fig. 12a.

[0132] Battery cell 1 is a prismatic battery cell and can, for example, be battery cell 1 made of Fig. 4, Fig. 5 or Fig. 6. Battery cell 1 comprises housing 2, in which the electrode stack (e.g. 6, Fig. 4, Fig. 5 or Fig. 6) are arranged. Housing 2 is closed on both sides in the x-direction with covers 4. A pressure relief valve 5, through which gas can escape from the battery cell 1, is also arranged in housing 2.

[0133] The left cover 4 of battery cell 1 contains an anode connection 3a. The opposite right cover 4 of battery cell 1 contains a cathode connection 3b. Anode connection 3a is, for example, one of the connection 3a from Fig. 4, Fig. 5 or Fig. 6. Cathode connection arrangement 3b is, for example, one of the connection arrangements 3b from Fig. 4, Fig. 5 or Fig. 6. Thus, the two connection arrangements 3a and 3b in the two covers 4 are designed differently, which enables optimized contacting according to the component and material properties of the electrodes (cathode and anode, respectively). Electrode stacks, anode and cathode discharge tabs, and connecting elements are arranged invisibly inside the housing 2.

[0134] Consequently, battery cell 1 is connected to the terminal arrangements (3a, 3b, ) for the purpose of the connection types adapted to the electrodes. Fig. 4, Fig. 5 or Fig. 6) contact-optimized and efficiently designed with regard to volume energy density, as well as optimized with regard to an efficient and effective manufacturing process. Reference symbol list 1 battery cell 2 cases 3 Connection arrangement 3a Anode connection arrangement 3b Cathode connection arrangement 4 lids 5 Overpressure valve 6 electrode stacks 7 drain flags 7a Anode drain tabs 7b Cathode drain tabs 10 U-shaped elements 10a Contact area 12 Bottom flap 12a Connection area (drain tab side) 12b Connection area (connection arrangement side) 13 weld seam 14 rivets 20 procedures 21. Welding the cathode drain tabs to the U-shaped element of the cathode cover plate 22 Welding the anode drain tabs to the lower tab 23. Inserting the electrode stack into the housing 24 Welding the bottom tab to the anode cover plate 25 Close the anode cover plate 30 procedures 31. Welding the cathode drain tabs to the cathode cover plate 32 Folding up the electrode stacks 33 Welding the anode drain tabs to the lower tab 34 Inserting the electrode stack into the housing 35 Welding the bottom tab to the anode cover plate 36 Close the anode cover plate 40 procedures 41 Welding the anode discharge tabs to the anode cover plate 42 Folding up the electrode stacks 43 Welding the cathode drain tabs to the lower tab 44 Inserting the electrode stack into the housing 45 Welding the bottom tab to the cathode cover plate 46. ​​Closing the cathode cover plate

Claims

[1] Battery cell (1) comprising an electrode stack (6) with alternatingly arranged anodes, separators and cathodes, a housing (2) in which the electrode stack (6) is arranged, an anode connection arrangement (3, 3a), a cathode connection arrangement (3, 3b), wherein the anode terminal arrangement (3, 3a) is arranged on one side of the battery cell (1) opposite the cathode terminal arrangement (3, 3b), anode drain tabs (7, 7a) for electrically connecting the anodes to the anode terminal arrangement (3, 3a), and Cathode drain tabs (3, 3b) for electrically connecting the cathodes to the cathode- Connection arrangement (3, 3b), wherein a connection type by which the anode drain tabs (7, 7a) and the anode connection arrangement (3, 3a) are connected is a different connection type than the connection type by which the cathode drain tabs (7, 7b) and the cathode connection arrangement (3, 3b) are connected, wherein one connection type is a flexible bottom tab comprising several layers, wherein the anode discharge tabs (7, 7a) are electrically connected to the anode terminal arrangement (3, 3a) by means of the flexible bottom tab (12) or by butterfly welding, and wherein the cathode drain tabs (7, 7b) are electrically connected to the cathode connection arrangement (3, 3b) by means of a U-shaped element (10), by means of the flexible lower tab (12) or by means of butterfly welding. [2] Battery cell (1) according to claim 1, further comprising two covers (4), which are designed as an anode-side cover (4) and an opposing cathode-side cover (4) for closing the housing (1), wherein the anode connection arrangement (3, 3a) is formed as part of the anode-side cover (4) which closes the housing (2) from a first side, and wherein the cathode connection arrangement (3, 3b) is formed as part of the cathode-side cover (4) which closes the housing (2) from a second side opposite the first. [3] Battery cell (1) according to any one of the preceding claims, wherein the flexible lower tab (12), by means of which the anode drain tabs (7, 7a) are electrically connected to the anode terminal arrangement (3, 3a) or the cathode drain tabs (7, 7b) are electrically connected to the cathode terminal arrangement (3, 3b), comprises two connection areas (12a, 12b) at two opposite ends of the flexible lower tab (12) and a bending area between the ends, and wherein the anode drain tabs (7, 7a) or the cathode drain tabs (7, 7b) are arranged on one of the connecting areas (12a) of the flexible bottom tab (12). [4] Battery cell (1) according to one of the preceding claims, wherein the flexible lower tab (12) by means of which the anode drain tabs (7, 7a) are electrically connected to the anode terminal arrangement (3, 3a) comprises copper. [5] Battery cell (1) according to one of the preceding claims, wherein the flexible lower tab (12) by means of which the cathode drain tabs (7, 7b) are electrically connected to the cathode connection arrangement (3, 3b) comprises aluminium. [6] Battery cell (1) according to one of the preceding claims, wherein the battery cell (1) comprises several electrode stacks (6). [7] Battery cell (1) according to one of the preceding claims, wherein butterfly welding comprises that the anode drain tabs (7, 7a) or the cathode drain tabs (7, 7b) are split and welded to different parts of the anode terminal assembly (3, 3a) or the cathode terminal assembly (3, 3b). [8] Battery cell (1) according to claim 7, wherein the battery cell (1) comprises two electrode stacks (6), and wherein the division of the anode drain tabs (7, 7a) or the cathode drain tabs (7, 7b) for butterfly welding comprises a division of the anode drain tabs (7, 7a) or the cathode drain tabs (7, 7b) according to electrode stacks (6). [9] Method (20; 30; 40) for manufacturing a battery cell (1) according to any one of claims 2 to 8, comprising the steps: - Connect (22, 24; 33, 35; 41) the anode drain tabs (7, 7a) to the anode connection arrangement (3, 3a); - Connect (21; 31; 43, 45) the cathode drain tabs (7, 7b) to the cathode connection arrangement (3, 3b); - Inserting (23; 34; 44) the electrode stack (6) into the housing (2); and - Closing (25; 36; 46) the housing (2) by closing at least one cover (4). [10] Method (20; 30) according to claim 9, comprising connecting (22, 24; 33, 35) the anode drain tabs (7, 7a) to the anode connection arrangement (3, 3a), welding (22; 33) the anode drain tabs (7, 7a) to the flexible lower tab (12) and welding (24; 35) the flexible lower tab (12) to the opened anode-side cover (4), and comprising connecting (21; 31) the cathode drain tabs (7, 7b) to the cathode connection assembly (3, 3b), welding (21) the cathode drain tabs (7, 7b) to the U-shaped element (12) or butterfly welding to the cathode connection assembly (3, 3b), and wherein closing (25; 36) the housing (2) by folding down the at least one cover (4) includes folding down the anode-side cover (4) with the welded-on flexible bottom flap (12). [11] Method (40) according to claim 9, comprising connecting (41) the anode drain tabs (7, 7a) to the anode connection assembly (3, 3a), butterfly welding the anode drain tabs (7, 7a) to the anode connection assembly (3, 3a), and comprising connecting (43, 45) the cathode drain tabs (7, 7b) to the cathode connection arrangement (3, 3b), welding (43) the cathode drain tabs (7, 7b) to the flexible lower tab (12) and welding (45) the flexible lower tab (12) to the opened cathode-side cover (4) , and wherein closing (46) the housing (2) by folding down the at least one cover (4) includes folding down the cathode-side cover (4) with the welded-on flexible bottom flap (12).

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