Monocell stack for a battery cell
Patent Information
- Application Number
- EP2023761819
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-09-01
- Filing Date
- 2023-08-23
- Publication Date
- 2025-07-09
AI Technical Summary
Existing methods for manufacturing battery cell electrode/separator stacks face challenges in achieving high process speed and reduced manufacturing effort for large-scale production.
A mono-cell stack is created by alternately stacking electrode sheets, separator sheets, and counter-electrode sheets, with the double sheet layer folded around the electrode sheet in a U-fold, allowing for efficient cutting, folding, and lamination processes to form a monocell stack, which can be further assembled into a series production format.
This approach enables faster series production of battery cell stacks with reduced manufacturing effort, enhancing process speed and scalability compared to traditional Z-folding methods.
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Abstract
Description
[0001] Description
[0002] Monocell stack for one battery cell
[0003] The invention relates to a mono-cell stack for a battery cell according to the preamble of claim 1 and to a method or a process arrangement for producing such a mono-cell stack according to claim 10.
[0004] An electrode / separator stack for a battery cell can, for example, be manufactured using a Z-folding process, in which a continuous separator web is folded in a Z-fold around superimposed electrode sheets. Alternatively, the electrode / separator stack can be manufactured as a generic monocell stack. This comprises a number of monocells stacked one on top of the other in the stacking direction. Each of the monocells is assembled into a one-piece assembly from an electrode sheet, a separator sheet, a counterelectrode sheet, and another separator sheet, for example, in a lamination station. The series production of such a monocell stack can be carried out at a significantly higher process speed than with an electrode / separator stack manufactured using a Z-folding process.
[0005] An electrode assembly is known from US 2019 / 0189976 A1. A rechargeable battery is known from EP 3 246 979 A1. An electrode assembly and a method for producing such an electrode assembly are known from WO 2020 / 121044 A1. An electrode / separator stack for a battery cell is known from US 2010 / 0190081 A1. Another electrode assembly for a battery cell is known from EP 3242 346 A1.
[0006] The object of the invention is to provide a mono-cell stack for a battery cell that allows large-scale production, with greater process speed and / or reduced manufacturing effort compared to the prior art.
[0007] The object is achieved by the features of claim 1 or claim 10. Preferred developments of the invention are disclosed in the subclaims. The invention is based on a monocell stack for a battery cell, which has a number of monocells stacked one above the other in the stacking direction. Each of these monocells is assembled from an electrode sheet, a separator sheet, a counterelectrode sheet, and a further separator sheet, alternating in the stacking direction. According to the characterizing part of claim 1, the two separator sheets are components of a double sheet layer. The double sheet layer is folded around the electrode sheet in a U-fold along a folded edge. The counterelectrode sheet is arranged on the outside of one of the separator sheets.
[0008] A process arrangement for producing such a monocell stack comprises the following process steps: First, the electrode sheet, the counterelectrode sheet, and the double-sheet layer are cut from a continuous web in a cutting device. The electrode sheet is then placed on the double-sheet layer in a first laying device. In the further process sequence, the double-sheet layer is folded around the electrode sheet along the folded edge using a folding device. The counterelectrode sheet is then placed on the outside of one of the separator sheets using a second laying device. The still loose sheet structure is then fed to a laminating device, in which the electrode and separator sheets are laminated to form the monocell. The finished monocell is transferred to a stacking device, in which the monocells are stacked to form the monocell stack.
[0009] In a preferred embodiment, the mono-cell stack can be terminated in the stacking direction with a counterelectrode sheet at each of its two stack ends. The counterelectrode sheet can preferably be an anode sheet, while the electrode sheets can be implemented as cathode sheets.
[0010] According to a first embodiment, the monocells can be stacked in the monocell stack with an identically repeating electrode-separator sheet sequence in the stacking direction, starting from a first stack end and ending at a second stack end. An end-side monocell with an external counterelectrode sheet (preferably an anode sheet) can be arranged at the first stack end. In contrast, an end-side monocell with an external separator sheet can be arranged at the second stack end. A single counterelectrode sheet (i.e., in particular, an anode sheet) can preferably be stacked on the external separator sheet of the second stack end. The single counterelectrode sheet is manufactured in an upstream process step as a separate unit, i.e., independently of the monocells.In a further embodiment, a single electrode sheet (preferably a single anode sheet) can be stacked on the outer counterelectrode sheet of the first stack end, with a separator sheet sandwiched between them. The single electrode sheet and the separator sheet can be combined into a layered composite before the stacking process. This layered composite can be stacked on the outer counterelectrode sheet during the stacking process.
[0011] In a further embodiment, the mono-cell stack can be divided into at least two sub-stacks in the stacking direction. In the first sub-stack, the mono-cells can be stacked with an identically repeating electrode-separator sheet sequence in the stacking direction. The second sub-stack can be reversed by 180° compared to the first sub-stack. In this case, the mono-cells in the second sub-stack are stacked with an inverted, identically repeating electrode-separator sheet sequence in the stacking direction.
[0012] The two partial stacks are located opposite each other in the stacking direction, each with a separator sheet of the double sheet layer, with a single counter electrode sheet (in particular an anode) interposed.
[0013] The electrode sheets and / or the counterelectrode sheets can each be formed in a conventional manner from a current collector foil with an electrode coating on both sides. Furthermore, the electrode sheets and / or the counterelectrode sheets can each be extended with laterally projecting collector tabs. In a first embodiment, the folded edges of the double-sheet layers in the single-cell stack can be arranged alternately on opposite sides of the single-cell stack, viewed in the stacking direction. Alternatively, the folded edges of the double-sheet layers in the single-cell stack can be arranged on the same side of the single-cell stack.
[0014] The conductor tabs of the electrode sheets and / or the counter electrode sheets can, for example, be aligned parallel to the folded edges. Alternatively, the conductor tabs of the electrode sheets can protrude on the side opposite the folded edge.
[0015] Exemplary embodiments of the invention are described below with reference to the accompanying figures. They show:
[0016] Figures 1 to 3 show a monocell stack according to a first embodiment; Figures 4 to 6 each show views illustrating a process sequence for producing the monocell stack;
[0017] Figures 7 to 11 show further variants of the monocell stack.
[0018] Figure 1 shows a monocell stack for a battery cell, which is made up of a number of monocells 1 stacked one on top of the other in the stacking direction. Figure 3 shows one of the monocells M on its own. Accordingly, the monocell 1 is made up (from top to bottom) of a cathode sheet K, a separator sheet S1, an anode sheet A and a further separator sheet S2, which are joined together in a lamination process. The cathode sheet K and the anode sheet A are each formed in a manner known per se from a current collector foil 3 which is coated on both sides with an electrode coating 5. The current collector foil 3 is in each case extended by a cathode-side collector lug 7 (Figures 8 to 11) and an anode-side collector lug 9 (Figures 8 to 11).
[0019] As can be seen from Figures 2 or 3, the two separator sheets S1, S2 are components of a double sheet layer D. The double sheet layer D is folded in a U-fold along a folded edge 11 around the cathode sheet K. The anode sheet A is arranged on the outside of the lower separator sheet S2 in Figure 3.
[0020] According to Figures 1 or 2, the monocell stack terminates in the stacking direction at each of its two stack ends with an anode sheet A. Furthermore, the monocell stack in Figures 1 and 2 is divided into two partial stacks 13, 15 in the stacking direction. In the upper first partial stack 13, the monocells M are stacked with an electrode-separator-sheet sequence that repeats identically in the stacking direction, i.e. from bottom to top with the first separator sheet S1, the cathode sheet K, the second separator sheet S2 and the anode sheet A. In the same way, in the lower second partial stack 15, the monocells M are stacked with an electrode-separator-sheet sequence that repeats identically in the stacking direction, i.e. from top to bottom with the first separator sheet S1, the cathode sheet K, the second separator sheet S2 and the anode sheet A. The lower second partial stack 15 is therefore turned over by 180° compared to the upper first partial stack 13.In the sheet sequence in the second partial stack 15, the anode sheet A of each monocell M is positioned at the bottom, followed by the second separator sheet S2, the cathode sheet K and the first separator sheet S. According to the exploded view of Figure 2, the two partial stacks 13, 15 are therefore located opposite each other in the stacking direction, each with the first separator sheet S1 of the respective double sheet layer D, with an individual anode sheet AE interposed, which is not part of a monocell M, but rather is manufactured separately.
[0021] In Figure 1 or 2, all folding edges 11 of the first partial stack 13 are positioned on one monocell stack side, while the folding edges 11 of the second partial stack 15 are positioned on the opposite monocell stack side.
[0022] Figures 4 to 6 describe a process sequence for producing the monocell stack shown in Figure 1: Accordingly, the cathode sheet K, the anode sheet A, and the double-sheet layer D are cut from continuous web material into individual sheets in a cutting device, as shown in Figure 4. Subsequently, the cathode sheet K is deposited on the double-sheet layer D in a first laying device (Figure 4). With the aid of a folding device, the double-sheet layer D is folded around the cathode sheet K in a U-fold along the folded edge 11 (Figure 5). In a further process step (Figure 6), the anode sheet A is positioned on the outside of the separator sheet S2. This is followed by a lamination (not shown), in which the individual sheets are joined together in a laminating device while still loose as a monocell sheet structure. The monocells M are then stacked in a stacking device to form the monocell stack.
[0023] Figures 7 to 11 show further embodiments of the monocell stack. The monocell stack shown in Figure 7 is essentially identical in structure to the monocell stack shown in Figure 1. Unlike Figures 1 or 2, in Figure 7, all folded edges 11 are positioned on a common side of the monocell stack.
[0024] The mono-cell stack shown in Figure 8 essentially corresponds to the mono-cell stack shown in Figure 7. In contrast to Figure 7, in Figure 8, the collector tabs 7, 9 each protrude outward at right angles to the folded edges 11. Accordingly, the cathode-side collector tabs 7 are extended toward the left side of the mono-cell stack, while the anode-side collector tabs 9 are extended toward the right side of the mono-cell stack.
[0025] Figure 9 shows a further monocell stack which is not formed from two stacks 13, 15 with an intermediate central anode AE. Rather, in Figure 9 the monocells M are stacked with an identically repeating electrode-separator sheet sequence in the stacking direction S, from an upper first stack end to a lower second stack end. At the upper first stack end, an end-side monocell M with an external anode sheet A is arranged. In contrast, at the lower second stack end, an end-side monocell M with an external separator sheet S1 is arranged. An individual anode sheet AE is additionally stacked on the external separator sheet S1 of the lower second stack end.
[0026] In Figure 10, the monocells M are constructed differently than in the previous figures: In each monocell M, the double sheet layer D is no longer folded around the cathode sheet K, but rather around the anode sheet A. The cathode sheet K is arranged on the outside of the separator sheet S2. The monocells M are stacked in a similar way to Figure 9, with an identical electrode-separator-sheet sequence repeating in the stacking direction, again from an upper first stack end to a lower second stack end. At the upper first stack end, an end-side monocell M with an external first separator sheet S1 is arranged. At the lower second stack end, an end-side monocell M with an external cathode sheet K is arranged.A layered composite 17 is stacked on the outer cathode sheet K of the lower first stack end. The composite layer 17 is formed from a single anode sheet AE around which a separator double layer is folded. The single anode sheet AE is therefore arranged on the lower cathode sheet K with a separator sheet S interposed.
[0027] Figure 11 shows a mono-cell stack according to a further embodiment. The mono-cell stack shown in Figure 11 is essentially identical in structure to the mono-cell stack shown in Figure 10. In contrast to Figure 10, in Figure 11, the anode-side and cathode-side conductor tabs 7, 9 protrude at right angles to the folded edges 11. The anode-side conductor tabs 9 protrude from the left side of the mono-cell stack, while the cathode-side conductor tabs 7 protrude from the right side of the mono-cell stack.
[0028] List of reference symbols
[0029] I Monocell
[0030] 3 current collector foil
[0031] 5 Electrode coating
[0032] 7 Cathode-side arrester lug
[0033] 9 Anode-side conductor lug
[0034] II Fold edge
[0035] 13, 15 partial stacks
[0036] 17 layer composite
[0037] M monocell
[0038] A anode sheet
[0039] K Cathode sheet
[0040] D Double sheet layer
[0041] S, S1, S2 separator sheets
Claims
Patent claims Monocell stack for a battery cell, with a number of monocells (M) stacked one above the other in the stacking direction, each monocell (M) being assembled from an electrode sheet (K), a separator sheet (S1), a counterelectrode sheet (A), and a further separator sheet (S2) alternating in the stacking direction, characterized in that the two separator sheets (S1, S2) are components of a double sheet layer (D) which is folded around the electrode sheet (K) in a U-fold along a folded edge (11), and in that the counterelectrode sheet (A) is arranged on the outside of one of the separator sheets (S1, S2). Monocell stack according to claim 1, characterized in that the monocell stack terminates in the stacking direction at both stack ends with a counterelectrode sheet (A).Monocell stack according to claim 1 or 2, characterized in that the monocells (M) are stacked in the monocell stack with an electrode-separator-sheet sequence that repeats identically in the stacking direction, from a first stack end to the second stack end, and in that in particular an end-side monocell (M) with an external counterelectrode sheet (A) is arranged at the first stack end and an end-side monocell (11) with an external separator sheet (S2) is arranged at the second stack end, and in that in particular an individual counterelectrode sheet (AE) is stacked on the external separator sheet (S2) of the second stack end.A monocell stack according to claim 3, characterized in that an individual electrode sheet (AE) is stacked on the outer counterelectrode sheet (K) of the first stack end, specifically with a separator sheet (S) interposed therebetween, and in particular that the individual electrode sheet (AE) and the separator sheet (S) are joined together before the stacking process to form a layered composite (17) that is stacked on the outer counterelectrode sheet (K). A monocell stack according to claim 1 or 2, characterized in that the monocell stack is divided into at least two partial stacks (13, 15) in the stacking direction, and that in the first partial stack (13) and in the second partial stack (15), the monocells (M) are stacked with an electrode-separator-sheet sequence that repeats identically in the stacking direction. and the second partial stack (15) is folded over by 180° relative to the first partial stack (13), so that in the second partial stack (15), the monocells (11) are stacked with an inverted electrode-separator-sheet sequence that repeats identically in the stacking direction. Monocell stack according to claim 5, characterized in that the two partial stacks (13, 15) are opposite one another in the stacking direction, each with a separator sheet (S1) of the double sheet layer (D), with a single counterelectrode sheet (AE) interposed. Monocell stack according to one of the preceding claims, characterized in that the electrode sheets (K) and / or the counterelectrode sheets (A) are each formed from a current collector foil (3) with an electrode coating (5) on both sides, and / or that the electrode sheets (K) and / or the counterelectrode sheets (A) are each extended by laterally projecting collector tabs (7, 9).A monocell stack according to one of the preceding claims, characterized in that the folded edges (11) of the double sheet layers (D) in the monocell stack are arranged alternately on opposite sides of the monocell stack, viewed in the stacking direction, or are arranged on the same side of the monocell stack. A monocell stack according to claim 7 or 8, characterized in that the conductor tabs (7, 9) of the electrode sheets (K) and / or the counterelectrode sheets (A) protrude outwardly parallel to the folded edges (11), or that the conductor tabs (7, 9) of the electrode sheets (A, K) protrude outwardly on the side opposite the folded edge (11).Process arrangement or method for producing a monocell stack according to one of the preceding claims, with a cutting device in which the electrode sheet (K), the counterelectrode sheet (A) and the double sheet layer (D) are cut from web material, a first laying device in which the electrode sheet (K) is laid on the double sheet layer (D), a folding device in which the double sheet layer (D) is folded around the electrode sheet (K) along a folding edge (11) in a U-fold, a second laying device in which the counterelectrode sheet (A) is arranged on the outside on one of the separator sheets (S1, S2), a laminating device in which the electrode and separator sheets (S1, K, S2, A) are laminated to form a. Monocell (M) are laminated, and a stacking device in which the monocells (11) are stacked.