Prismatic battery cell and method for manufacturing such a battery cell

Abstract

The invention relates to a prismatic battery cell with a dimensionally stable metal cell casing (1) comprising a cell cup (3) having a component opening (11) and a cell cover (5) that closes the component opening (11). According to the invention, the cell cup (3) and the cell cover (5) are formed together from exactly one blank (42). In a joint forming process, the cell cup (3) and the cell cover (5) are formed from the blank (42) into a target geometry in which the cell cup (3) and the cell cover (5) are joined together in one piece and made of a single material.

Description

[0001] The invention relates to a method for manufacturing a prismatic battery cell according to the preamble of claim 1 and a battery cell according to claim 9.

[0002] In a manufacturing process, the cell casing of a prismatic battery cell is formed in multiple stages from a deep-drawn or extruded aluminum cup, onto which a separately manufactured cell lid is laser-welded. A Mylar film, which must be heat-sealed, provides electrical insulation between the winding material (jelly roll) and the casing. The lid contains one or more terminal openings and an electrolyte filling port, which, after filling, is first temporarily sealed with a rubber stopper and then permanently sealed with a metal cap. A separate, thin aluminum membrane, laser-welded to the casing, is provided for degassing. A current-disconnect device (CID) is either not included in many known designs or is only installed separately within the cell.

[0003] The following problems arise in the process defined above: One problem is that the use of Mylar film requires additional manufacturing and assembly steps, which are associated with increased material costs, additional weight, and additional process effort. Mechanical damage to the film can occur when inserting the Mylar-wrapped component into the housing, especially if there are unfavorable dimensional tolerances between the cell cup and the component. The Mylar film can obstruct the gas flow to the degassing membrane, thereby increasing the degassing pressure. Perforation or channeling of the film is possible, but this leads to a reduction in the insulating effect.

[0004] Furthermore, the two-stage electrolyte filling process requires a temporary rubber element and a metallic seal, which necessitates additional components and process steps. The rubber element ages and loses its elasticity, potentially leading to leaks, especially during the sensitive formation phase. Laser welding of the metallic insert results in a locally concentrated heat input, which can cause the separator to shrink and thus compromise cell safety.

[0005] Furthermore, in the prior art, the separate cell lid must be joined to the cell cup by laser welding, which increases the cell weight and requires additional joining processes. Here, too, the heat input can lead to structural damage to the separator.

[0006] The degassing membrane integrated into the familiar cell housing is a separate component that must be sourced separately and welded in place using a critical laser process. Damage or faulty installation can lead to leaks. After degassing is triggered, the cell's circuit remains closed, which can cause thermal runaway if oxygen enters the cell. An integrated power interruption device is often not present.

[0007] Aluminum from the 3xxx series, used as a casing material, is highly susceptible to corrosion by certain electrolytes, especially LiFSI. If the casing is also used as the positive cell terminal, pitting corrosion can be accelerated, leading to hydrogen release.

[0008] Furthermore, the heat dissipation from the center of the cell to the cooling plate can be hindered by the Mylar film and outer insulation layers, making the thermal management of the cell more difficult.

[0009] A prismatic battery cell of this type with a dimensionally stable metal cell casing and a method for its manufacture are known from US 2025 / 0105401 A1. Further methods for manufacturing a prismatic battery cell are known from DE 10 2016 121089 A1, DE 10 2016 109214 A1, and DE 10 2013 109837 A1. DE 10 2022 212333 A1 discloses a method for manufacturing a cell casing for a prismatic battery cell of a traction battery for a motor vehicle. The cell casing has an interior enclosed by walls and openings on opposite sides that can be closed by means of casing covers. It is manufactured by bulk forming of a semi-finished product. The bulk forming is carried out by extrusion.

[0010] The object of the invention is to provide a method for manufacturing a prismatic battery cell which is easier to manufacture in terms of process technology compared to the prior art.

[0011] The problem is solved by the features of claim 1 or 9. Preferred embodiments of the invention are disclosed in the dependent claims.

[0012] The invention relates to a prismatic battery cell with a dimensionally stable metal cell housing, which has a cell cup with a component opening and a cell cover, wherein the cell cup and cell cover are formed together from exactly one blank and are transformed in a common forming process to a target geometry in which they are joined together in a single piece and with a uniform material.

[0013] The inventive, one-piece, and material-uniform formation of the cell cup and cell lid from a single blank enables a significant reduction in the number of components. This simplifies the structural design of the battery cell and makes the manufacturing process considerably more efficient. Since a separate joining point between the cell cup and cell lid is no longer required, the previously necessary laser welding process at the lid edge is eliminated. This not only reduces manufacturing costs but also minimizes the risk of leaks, manufacturing defects, and heat-related material damage. Furthermore, manufacturing from a single blank improves the dimensional accuracy of the cell housing structure. The forming process allows for a mesh-geometric shaping with manufacturing tolerances below 0.1 mm, resulting in a precise and reproducible housing geometry.Simultaneously, eliminating external lid components reduces cell weight, which has a positive effect on gravimetric energy density. A further advantage is that the one-piece housing design offers higher structural integrity, as there are no mechanically critical joints. This is particularly relevant from a safety perspective with regard to pressure loads in the event of a failure. Moreover, the manufacturing concept is transferable to various materials and cell formats, thus ensuring application-specific flexibility. The blank can be made of aluminum, stainless steel, or nickel-plated steel and can be used for both prismatic and cylindrical cells.Finally, the integration of several functional elements within a single forming step significantly reduces the number of process steps, thereby reducing the overall effort in cell production and increasing efficiency. According to the invention, the forming process is a single-stage forming operation using indirect extrusion, which is implemented in a forming tool with a stationary die and at least one stroke-adjustable punch. In at least one forming stroke, the blank is transformed into the target geometry of the cell cup and / or cell lid by displacing the material along a gap formed between the die and punch. This measure enables highly precise and reliable forming of the cell housing with low friction between the tool and the workpiece, thereby reducing tool wear and improving the dimensional accuracy of the components.The indirect extrusion process offers the additional advantage that the material can be precisely controlled within complex geometric areas, which is particularly important for functional structural elements such as degassing zones or filling openings. The single-stage forming process significantly increases manufacturing efficiency, as the cell housing is completely produced in just one tool stroke, thus replacing several previously separate forming or joining operations. Alternatively, a deep-drawing process can also be used instead of indirect extrusion.

[0014] In one specific embodiment, the cell cup, after the forming process, has a rectangular base from which side walls with a forming height are extended along the edges. One of the side walls is made of the same material and is integrally extended with the cell lid. After removal from the forming tool, the cell lid is aligned parallel to the base and angled outwards at a right angle at a transition edge of the side wall. During assembly, the cell lid can be folded over this transition edge, acting as a hinge axis, into a closed position where it closes the insertion opening. The remaining exposed edges can be welded to the cell cup. This design enables a particularly easy-to-assemble housing structure, in which the cell lid remains firmly connected to the cell cup throughout the entire cell assembly process.This eliminates the need for separate handling of a lid component and simultaneously ensures the correct positioning of the lid when the cell is later closed. Furthermore, the seamless extension of a side wall into the lid area creates a defined hinge axis, allowing for a reproducible, tolerance-controlled joining geometry. Additionally, the effort required for the final lid welding is minimized, as only three side edges need to be joined – the fourth side is already an integral part of the cell structure.

[0015] In one specific embodiment, the housing base features a degassing zone designed as a material thinning area with a reduced wall thickness compared to the adjacent base region, and specifically as a predetermined breaking point. This measure enables targeted pressure relief in the event of a failure, with controlled degassing occurring at a structurally defined weak point. Integrating the degassing zone into the housing base during the forming process ensures that no additional degassing component needs to be welded on, thus eliminating the risk of leaks due to joining defects. Furthermore, the costs for a separate degassing foil and the associated precise laser welding process are eliminated. The defined wall thickness reduction allows for precise adjustment of the opening pressure, which contributes to increased system safety in the event of an excessive gas pressure increase within the cell.

[0016] In a specific embodiment, the cell cover has at least one terminal opening through which a cell terminal, particularly an anode-side terminal, of an electrode / separator arrangement located in the cell housing is led to the outside of the housing. The cell cover and the cell cup act, in particular, as the cathode-side cell terminal, with the cathode side of the electrode / separator arrangement being connected to the cell cup or the cell cover via a connection element. The connection element is preferably a single, integral component of the degassing zone formed in the housing base and acts as a current interrupter in the event of a pressure-induced rupture of the degassing zone. This measure allows for a particularly compact and functionally integrated design of the electrical connection structure.By using the cell housing as a dual current path on the cathode side, the need for a separate external cathode terminal is eliminated. This reduces material costs and simplifies the thermal and mechanical aspects of cell connection. Integrating the connection element into the degassing zone creates a highly effective safety feature: In the event of excessive internal pressure, not only is pressure relief ensured, but the current flow to the cathode is also reliably interrupted by the breaking or detachment of the connection element. This provides additional protection against potential thermal runaway.

[0017] In one specific embodiment, the cell lid has at least one electrolyte filling hole, which is formed during the forming process as a relief cut. A sheet metal tab, made of a single material, seamlessly transitions into a base section of the cell lid at a transition edge. In its unused position, the sheet metal tab is positioned above the filling hole. To initiate the filling process, a filling nozzle elastically pivots the tab, thus exposing the filling hole. After the nozzle is removed, the sheet metal tab returns to its original position due to restoring forces, temporarily closing the filling hole. The same mechanism can be used again for a second filling process and subsequently permanently sealed by laser welding. This design enables an integral and reliable electrolyte filling opening without separate components such as rubber stoppers or metal caps.This accelerates, simplifies, and standardizes the filling process. In particular, error-prone assembly and disassembly steps involving temporary sealing elements are eliminated. The automatic return of the sheet metal tab to the closed position also increases process reliability between filling operations and reduces the risk of moisture ingress. The final closure, achieved through spot laser welding, saves material and is limited to a defined segment, thus minimizing the thermal impact on the cell housing.

[0018] In one specific embodiment, the cell lid has at least one electrolyte filling hole, which is formed during the forming process as a relief cut. A sheet metal tab, made of a single material, seamlessly transitions into a base section of the cell lid at a transition edge. In its unused position, the sheet metal tab is positioned above the filling hole. To initiate the filling process, a filling nozzle elastically pivots the tab, thus exposing the filling hole. After the nozzle is removed, the sheet metal tab returns to its original position due to restoring forces, temporarily closing the filling hole. The same mechanism can be used again for a second filling process and subsequently permanently sealed by laser welding. This design enables an integral and reliable electrolyte filling opening without separate components such as rubber stoppers or metal caps.This accelerates, simplifies, and standardizes the filling process. In particular, error-prone assembly and disassembly steps involving temporary sealing elements are eliminated. The automatic return of the sheet metal tab to the closed position also increases process reliability between filling operations and reduces the risk of moisture ingress. The final closure, achieved through spot laser welding, saves material and is limited to a defined segment, thus minimizing the thermal impact on the cell housing.

[0019] To support the temporary sealing of the electrolyte filling hole, a sealing tape, particularly a polypropylene tape, can be provided. This tape covers the filling hole, creating a helium-tight temporary seal. This measure improves the functionality of the temporary closure between electrolyte filling processes. The sealing tape serves as an additional, easy-to-apply, and cost-effective sealing aid, complementing the mechanical restoring force generated by the metal tab. This reliably prevents the ingress of moisture or foreign particles, especially during storage or transport between filling steps. At the same time, the tape remains reversibly removable without damaging the housing structure. This allows for flexible and trouble-free further processing in automated manufacturing processes and contributes to increased cell quality.

[0020] In one specific embodiment, the blank is a tailored rolled blank or a tailored welded blank and can be subdivided into a cell cup section and a cell lid section, with the cell cup section having a reduced material thickness compared to the cell lid section. Additionally, functional elements such as the degassing zone, connection element, electrolyte filling hole, and terminal opening are formed during the forming process. This allows for a material- and manufacturing-optimized design of the cell housing. By using tailored blanks with different sheet thicknesses, areas subject to higher mechanical or thermal stresses can be selectively reinforced, while less stressed zones can be designed to save weight and material.This results in a functionally optimized housing with a tailored strength profile that simultaneously meets the requirements for pressure resistance, weldability, and formability. The ability to form multiple functional housing elements directly during the forming process reduces the number of downstream machining steps and allows for particularly economical series production with high dimensional accuracy and functional integration.

[0021] The following are examples of implementation described with reference to the accompanying figures. They show: Fig. Figures 1 to 9 show different views illustrating the structure and manufacture of a battery cell according to the invention.

[0022] In the Fig. 1 and Fig. Figure 2 shows a battery cell in its assembled state, to the extent necessary for understanding the invention. Accordingly, the prismatic battery cell has a dimensionally stable aluminum cell housing 1, which is composed of a cell cup 3 and a cell cover 5. The cell cup 3 is formed from a rectangular housing base 7 with side walls 9 that extend upwards at its edges. The upper surfaces of these side walls define a component opening 11, through which an electrode / separator arrangement 13 is inserted into the interior of the cell housing during the cell manufacturing process. The cell cover 5 is located in the Fig. 1 or Fig. 2 is welded to the top of the cell cup 3 via a laser weld seam 13 to close the component opening 11. An anode-side cell terminal 15 is located in the cell cover 5. This terminal is guided through a cell terminal opening 19 of the cell cover 5, with an intermediate layer of electrical insulation 17, and is in electrical contact with an anode side 21 of the electrode / separator assembly 13.

[0023] In the present embodiment, the cell cover 5 and the cell cup 3 act as a cathode-side cell terminal. For this purpose, the cathode side 23 of the electrode / separator arrangement 13 is electrically connected to the housing base 7 via a connecting element 25. The housing base 7 has in the Fig. 2 a degassing zone 27. This zone is designed as a material thinning area with a reduced material thickness compared to the adjacent housing base area and features predetermined breaking points 29. The cathode-side connection element 25 is a single, integral component of the degassing zone 27 and is soldered or welded to the cathode side 23 of the electrode / separator assembly 13. If an excessively high pressure rise occurs inside the cell housing during cell operation, the degassing zone 27 ruptures at the housing base 7. The overpressure-induced rupture of the degassing zone 27 also causes the connection element 25 to tear, thus interrupting the current path from the cathode side 23 to the cell cup 3.

[0024] As from the Fig. 1 and Fig. As further shown in Figure 2, an electrolyte filling hole 31 is provided in the cell lid 5. The cell housing interior is filled with electrolyte in a first filling process and a second filling process during the cell manufacturing process. According to the Fig. 1 and Fig. 2 the electrolyte filling hole 31 is designed as a free-cut, in which a sheet metal tab 33 is made of a single material and in one piece at a transition edge (defining a hinge axis K) ( Fig. 1 or Fig. 2) transitions into a cell cap base section. In the Fig. Figure 3a shows the metal tab 33 in a non-use position, in which the metal tab 33 closes the electrolyte filling hole 31. To start the first electrolyte filling process, the metal tab 33 is moved into an open position by means of a filling nozzle 37, generating an elastic restoring force on the metal tab ( Fig. 3b) opened so that the filling nozzle 37 can introduce electrolyte into the cell housing 1. At the end of the first electrolyte filling process, the filling nozzle 37 is removed from the electrolyte filling hole 31, causing the sheet metal tab 33 to return to its non-use position as the elastic sheet metal tab restoring force dissipates ( Fig. 3a) returns. In the non-use position, the electrolyte filling hole 31 is temporarily covered by means of the sheet metal tab 33. To support this temporary cover, in the Fig. 3c a polypropylene tape 39 is provided which adheres to the cell lid 5 and covers the electrolyte filling hole 31.

[0025] At the end of the second electrolyte filling process, the sheet metal tab 33 is permanently sealed to the opening edge of the electrolyte filling hole 31 by means of a laser weld 41, as shown in the Fig. 3D as well as in the Fig. 1 is shown.

[0026] A key aspect of the invention is that the cell cup 3 and the cell lid 5 are made from exactly one single blank 42 ( Fig. 4) are formed. In a joint forming process, the cell cup 3 and the cell lid 5 are formed into a target geometry in which the cell cup 3 and the cell lid 5 are joined together in one piece (i.e., without an additional weld) using a uniform material. In addition, the degassing zone 27, the connection element 25, the electrolyte filling hole 31 with the sheet metal tab 33, and the terminal opening 19 are formed during this forming process.

[0027] The forming process is described below using the following examples: Fig. Figures 4 to 6 indicate that this is a single-stage forming process using indirect extrusion. The forming process is carried out in a forming tool 43, which consists of a stationary matrix 45 and two stroke-adjustable punches, namely a cell cup punch 47 and a cell lid punch 49.

[0028] As in Fig. As indicated in Figure 4, the blank 42 is first inserted into the open tool cavity of the forming tool 43. The blank 42 is designed as a tailored rolled blank or tailored welded blank and comprises a cell cup section 51 and a cell lid section 53, the latter having a greater material thickness compared to the cell cup section 51.

[0029] The forming process then begins. In the first step of the forming process, the cell lid punch 49 can perform a hold-down function, in which the cell lid section 53 of the blank 42 is pressed against the die 45 with a holding force, while the cell cup punch 47 performs a forming stroke. During the forming stroke, the cell cup section 51 of the blank 42 is transformed into the target cell lid geometry, whereby the blank material is displaced by indirect extrusion along a gap between the cell cup punch 47 and the die 45.

[0030] In a second step, the cell lid 5 is formed into its target geometry. For this purpose, the cell lid punch 49 performs a press stroke, while the cell cup punch 47 presses the cell cup 3 against the die 45 with a holding force. The cell lid punch 49 has in the Fig. 4 or Fig. The system comprises five independent functional elements: hold-down elements 52, a punching element 54, and a cutting element 55, all of which are independently adjustable in stroke. The punching element 54 punches out the terminal opening 19 in the cell lid 5. The cutting element 55 creates the clearance for the electrolyte filling hole 31.

[0031] After completion of the forming process, the component assembly consisting of cell cover 5 and cell cup 3 is removed from the forming tool 43. In the Fig. Figure 6 shows the intermediate product removed from the forming tool 43. Accordingly, the side wall 9 is made of the same material and is integrally extended with the cell cover 5. After removal from the forming tool 43, the cell cover 5 is aligned parallel to the housing base 7 and angled outwards at a right angle from the right side wall 9 at a transition edge 57. In the cell manufacturing process, the transition edge 57 defines a hinge axis around which the cell cover 5 is folded into a closed position, in which the cell cover 5 closes the loading opening 11 of the cell cup 3. In this state, the remaining exposed edges of the cell cover 5 are laser-welded to the opening edge of the cell cup 3. A material weakening 58 is embossed in the transition edge 57 to ensure smooth folding.

[0032] In the Fig. 7 and Fig. Figure 8 shows the electrolyte filling hole 31 according to a second embodiment. In this embodiment, the electrolyte filling hole 31 – in contrast to the previous embodiment – ​​is designed as a straight slot. During the electrolyte filling process ( Fig. 8) The filling nozzle 37 is pressed directly into the straight slot, causing the two lateral longitudinal flanks 59 of the slot to be brought into their opening position under elastic deformation.

[0033] In the Fig.Figure 9 shows a further embodiment of the invention in which the connecting element 25 no longer electrically connects the cathode side 23 of the electrode / separator arrangement 13 to the housing base 7, but rather to the cell cover 5. In this case, the connecting element 25 is a single, integral component of the cell cover 5. The connecting element 25 is connected to the cathode side 23 of the electrode / separator arrangement via a solder joint 61 with a low melting point. If the temperature inside the cell housing rises excessively high, exceeding the melting point, the solder joint 61 fails. This interrupts the current path from the cathode side 23 of the electrode / separator arrangement 13 to the cell cover 5. The connecting element 25 also incorporates predetermined breaking points 63. These break under excessive pressure inside the cell housing.This can also interrupt the current path from the cathode side 23 of the electrode / separator arrangement to the cell lid 5. Reference symbol list 1 cell casing 3 cell cups 5 cell lids 7 Case bottom 9 side wall 11. Loading opening 12 Laser weld seam 13 Electrode / Separator Arrangement 15 anode-side cell terminal 17 electrical insulation 19 Cell terminal opening 21 Anode side of the electrode / separator arrangement 23 Cathode side of the electrode / separator arrangement 25 Connection element 27 Degassing zone 29 Breakaway point 31 Electrolyte filling hole 33 sheet metal tab 35 Transition edge 37 Filling nozzle 39 sealing tape 41 Laser weld seam 42 blanks 43 Forming tool 45 die 47 cell cup stamps 49 cell lid stamps 51 Cell cup section 52 Holding element 53 Cell lid section 54 die-cut elements 55 Cutting element 57 Transition edge 59 lateral longitudinal flanks 61 Soldered connection 63 Breakaway point K Folding axle

Claims

[1] Method for manufacturing a prismatic battery cell with a dimensionally stable metal cell casing (1) having a cell cup (3) having a component opening (11) and a cell cover (5) that closes the component opening (11), wherein the cell cup (3) and the cell cover (5) are formed together from exactly one blank (42), and wherein the cell cup (3) and the cell cover (5) are formed from the blank (42) in a common forming process to a target geometry in which the cell cup (3) and the cell cover (5) are joined together in a single piece and with the same material, characterized by, that the forming process is realized as a single-stage forming process by means of indirect extrusion or by means of deep drawing, namely in a forming tool (43) consisting of a stationary die (45) and at least one stroke-adjustable punch (47, 49), and that in the single-stage forming process with at least one forming stroke of the punch (47, 49) the blank (42) can be transformed into the cell cup target geometry and / or into the cell lid target geometry, in which the blank material is displaced under indirect extrusion along a gap between the punch (47, 49) and the die (45). [2] Method according to claim 1, characterized by, that after the forming process the cell cup (3) has a rectangular housing base (7) from which side walls (9) are drawn up at the edges with a forming height, and that one of the side walls (9) is extended in one piece with the cell lid (5) in a uniform material, and that after removal from the forming tool (43) the cell lid (5) is aligned parallel to the housing base (5) and is angled outwards at a right angle at a transition edge (57) of the side wall (9), and that in an assembly process the transition edge (57) defines a hinge axis about which the cell lid (5) can be folded into a closed position in which the cell lid (5) closes the insertion opening (11) of the cell cup (3), and that in the assembly process the remaining free edge edges of the cell lid (5) can be welded to the opening edge of the cell cup (3). [3] Method according to claim 2, characterized by, that the housing base (7) has a degassing zone (27) which is designed as a material thinning with a reduced material thickness compared to the adjacent housing base area and with a predetermined breaking point (29). [4] Method according to any one of the preceding claims, characterized by, that the cell cover (5) has at least one terminal opening (19) through which an anode-side cell terminal (15) of an electrode / separator arrangement (13) arranged in the cell housing (1) is led to the outside of the housing, and that the cell cover (5) and the cell cup (3) act as a cathode-side cell terminal, and that when the battery cell is completed, the cathode side (23) of the electrode / separator arrangement (13) is connected to the cell cup (3) or to the cell cover (5) via a connecting element (24), and that the connecting element (25) is a single, integral component of the degassing zone (27) formed in the housing base (7) of the cell cup (3), and that in the event of a pressure-induced rupture of the degassing zone (27), the connecting element (25) tears and thereby acts as a current interrupter, interrupting a current path from the cathode side (23) of the electrode / separator arrangement (13) interrupts to the cell cup (3). [5] Method according to claim 4, characterized by , that the connecting element (25) is a single, integral component of the cell cover (5), and / or that the connecting element (25) is connected to the cathode side (23) of the electrode / separator assembly (13) via a solder joint (61) with a low melting point, and that the solder joint (61) dissolves in the event of an unacceptably high temperature rise inside the cell housing above the melting point, thereby interrupting the current path from the cathode side (23) of the electrode / separator assembly (13) to the cell housing (1), and / or that the connecting element (25) is associated with at least one predetermined breaking point (63) which tears under excessively high pressure inside the cell housing, thereby interrupting the current path from the cathode side (23) of the electrode / separator assembly (13) to the cell housing (1). [6] Method according to any one of the preceding claims, characterized by, that the cell lid (5) has at least one electrolyte filling hole (31) through which the cell housing (1) can be filled with electrolyte in at least one filling process, and that the electrolyte filling hole (31) is formed during the forming process as a free-cut, in which at least one sheet metal tab (33) transitions in one piece and with uniform material into a cell lid base section at a transition edge defining a hinge axis (K), and that in a non-use position the sheet metal tab (33) closes the electrolyte filling hole (31), and that to start the electrolyte filling process the sheet metal tab (33) is opened into an open position by means of a filling nozzle (37) by building up an elastic sheet metal tab restoring force in order to introduce the electrolyte into the cell housing (1),and that at the end of the filling process the filling nozzle (37) is removed from the electrolyte filling hole (31) and the sheet metal tab (33) returns to its non-use position as the elastic sheet metal tab restoring force dissipates, so that a temporary covering of the electrolyte filling hole (31) is achieved, and that a manufacturing process of the battery cell has at least two electrolyte filling processes spaced apart in time, and that at the end of the second electrolyte filling process the sheet metal tab (33) can be permanently sealed to the opening edge of the electrolyte filling hole (31) by means of laser welding. [7] Method according to claim 6, characterized by , that to support the temporary cover a sealing tape (39) is provided which covers the electrolyte filling hole (31) thereby enabling a helium-tight temporary seal to be achieved. [8] Method according to any one of the preceding claims, characterized by, that the blank (42) is a tailored rolled blank or a tailored welded blank, and / or that the blank (42) is divisible into a cell cup section (51) from which the cell cup (3) is formed, and into a cell lid section (53) from which the cell lid (5) is formed, and that the cell cup section (51) has a reduced material thickness compared to the cell lid section (53), and / or that the degassing zone (27), the connection element (25), the electrolyte filling hole (31) and the terminal opening (19) are formed during the forming process. [9] Prismatic battery cell manufactured according to a method according to any of the preceding claims.

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