Electrode stacks / separator stacks for battery cells, and methods for manufacturing such electrode stacks / separator stacks.

Abstract

To provide an electrode stack / separator stack and a method for manufacturing such electrode stack / separator stack, in which a stacking process is easier than the prior art in terms of manufacturing technology, and which may be carried out with greater accuracy of placement.SOLUTION: An electrode stack / separator stack for a battery cell comprises at least an electrode, in particular a cathode (K), and a counter electrode, in particular an anode (A). The electrode (K) is a constituent of a laminated composite (V), in which one separator (S) is laminated to each of the two sides of the electrode (K), and the two separators (S) protrude beyond the electrode (K) each with an overhang (a) on the edge side. An edge-side gap (9) between the two separator overhangs (a) is in particular completely filled with an edge protection film (11).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrode stack / separator stack for a battery cell according to the generic concept of claim 1, and a method for manufacturing such an electrode stack / separator stack according to the generic concept of claim 10.

[0002] Such an electrode stack / separator stack can be manufactured by stacking individual sheets. In the stacking of individual sheets, the placement accuracy of the electrode sheets and separator sheets in the electrode stack / separator stack is extremely important for the safety and performance of the battery cell. For example, the electrochemical performance of a battery cell with a relatively small overlap between electrodes will decline relatively rapidly during operation. Furthermore, incorrect placement of the sheets may lead to direct contact connection between the anode and the cathode, which may trigger a short circuit and a failure of the battery cell. In order to achieve complete overlap between the anode and the cathode despite inaccurate placement, for example, the anode in the electrode stack / separator stack may be larger by an oversize portion (for example, 1.5 mm) in the circumferential direction than the cathode, and the separator may be larger by the oversize portion than the anode.

[0003] The above-described stacking of individual sheets is carried out at high cost in terms of manufacturing technology using operating equipment. These operating equipment receive their coordinates based on image processing, in which, after each sheet placement, the position of each placed electrode sheet / separator sheet is optically detected and evaluated, thereby determining the placement accuracy.

[0004] Such optical detection of placement accuracy does not allow for positional correction of already placed electrode / separator sheets, which is performed after the stacking process. Therefore, while placement errors can be identified, they cannot be corrected afterward. Furthermore, additive manufacturing performed using image processing is technically costly and, due to system limitations, can result in positional deviations of individual sheets stacked within the electrode / separator stack.

[0005] From U.S. Patent Application Publication No. 2022 / 0148821, a battery cell is known having an inner element having a first main surface, a second main surface, a first side surface, a second side surface, a first end face, and a second end face. Furthermore, a first inner electrode extending to the first end face, a second electrode extending to the second end face, a separator layer disposed between the first and second electrodes, and an electrolyte are provided. Furthermore, the first electrode is disposed at the first end face and the second electrode is disposed at the second end face. The first electrode, the second electrode, and the separator layer form a single composite that is integrally bonded.

[0006] From German Patent Application Publication No. 102016217397, an electrode stack is known having an electrically insulating coating on at least one sheet edge side surface. This coating is applied from a liquid phase and extends over the entire height of the electrode stack.

[0007] A manufacturing method and apparatus for batteries having high battery performance are known from Japanese Patent Publication No. 5375263, and in the manufacturing apparatus, a number of laminates consisting of one electrode and one separator are formed.

[0008] The object of the present invention is to provide an electrode stack / separator stack in which the lamination process can be carried out more easily and with higher placement accuracy than in the conventional technology, as well as a method for manufacturing such an electrode stack / separator stack.

[0009] The above-mentioned problems are solved by the features of claim 1 or claim 10. Preferred developments of the present invention are disclosed in the dependent claims.

[0010] The present invention is based on an electrode stack / separator stack for a battery cell comprising at least an electrode, particularly a cathode, and a counter electrode, particularly an anode. The electrode is a component of a laminated composite, with one separator laminated to each side of the electrode. These two separators protrude from the electrode on the edge side by protrusions. According to the feature portion of claim 1, the edge-side gap between the two separator protrusions is preferably completely filled by an edge protection film. The edge protection film may have the same material thickness as the electrode when observed in the thickness direction of the laminated composite. In this way, the corners and edges of the electrode are protected from external mechanical loads using the edge protection film. The edge protection film can provide a shape-stable contact surface during the alignment process performed in the completed electrode stack / separator stack, which allows for damage-free lateral movement of the electrode within the electrode stack / separator stack. Furthermore, the edge protection film acts as an electrical insulator, enhancing the electrical safety of the battery cell.

[0011] The electrode stack / separator stack according to the present invention can be manufactured in the form of a laminated sheet structure, in which a laminated composite and a counter electrode are laminated together as individual sheets.

[0012] In technical embodiments, each separator may have an adhesive layer, which can be used to laminate the separator onto the electrode during a lamination process, thereby forming a laminated composite. In this way, the two separators and the electrode placed between them form a single structural unit that is already integrally bonded before the lamination process is performed, thereby increasing the lamination accuracy of the electrode stack / separator stack, especially compared to electrode stacks / separator stacks where the electrodes are laminated as individual sheets.

[0013] The electrodes and / or counter electrodes are formed from a substrate film. One or both sides of the substrate film are coated with an electrode active material. The active material has a binder, particularly a polymer binder, preferably PVDF. To avoid undesirable material combinations between the active material and the edge protection film, and possibly the adhesive layer, the active material binder, the edge protection film, and possibly the adhesive layer are formed from the same material. That is, both the adhesive layer and the edge protection film have the same material composition as the active material binder. This ensures the durability of the edge protection film against the electrolyte. Furthermore, it ensures that the material combination between the edge protection film and the active material binder is electrochemically stable or durable.

[0014] A laminated composite consisting of two separators and an electrode placed between them may be provided as a rectangular planar cut section. On one side of the cut section (hereinafter referred to as the "conductor piece side"), the substrate film of the electrode may be extended laterally outward by the conductor piece, beyond the separator edge. The edge-side gap, filled with an edge protection film, may extend continuously along at least the cut section side opposite to the conductor piece side, and along two cut section sides of the laminated composite perpendicular to the conductor piece side. The conductor piece side itself is not provided with an edge protection film, which allows the conductor piece to be removed from the composite. In this way, the thickening at the height of the conductor piece (caused by the edge protection film), which would later become noticeable, is avoided. Therefore, it is advantageous to provide the edge protection film on only three of the four cut section sides in total, thereby preventing the creation of thickened areas.

[0015] In order to achieve perfect superposition of the electrode (i.e., cathode) and the counter electrode (i.e., anode) despite inaccurate placement, the counter electrode may preferably be dimensionally set to be circumferentially larger than the electrode by an oversized portion, for example, 1 to 3 mm. Preferably, the counter electrode and the separator may be manufactured as a joint sheet cut. That is, the counter electrode is dimensionally set to have the same area and the same contour as the separator, except for its own conductive piece, so that the corners and edges of the counter electrode can be aligned with the corners and edges of the separator in the stacking direction.

[0016] A method for manufacturing electrode stacks / separator stacks can be divided into a lamination process and a subsequent alignment process. In the lamination process, a laminated composite consisting of separators and electrodes and a counter electrode are laminated together in the form of a stack of individual sheets. In the subsequent alignment process, the laminated composite and the counter electrode can be aligned in a line with respect to each other in the lamination direction. Based on the provision of edge protection film according to the present invention, the laminated composite is configured to be shape-stable, thereby allowing for damage-free repositioning of the laminated composite in the lateral direction relative to the lamination direction. Such a shape-stable laminated composite also provides a stable opposing hold or stable support base for adjacent counter electrodes, thereby allowing for damage-free repositioning of the counter electrodes. Preferably, at least one lateral stopper, particularly a slider, can be used in the alignment process. Lateral stoppers allow for the repositioning of stack components that are misaligned laterally with respect to the stacking direction, i.e., laminated composites or counter electrodes, enabling alignment with other stack components.

[0017] An edge protection film can be applied to a laminated composite in any suitable manner. For example, the edge protection film can be applied to the laminated composite during a coating process, in which case the viscous base component of the edge protection film is directly applied to the gaps on the edge side of the laminated composite. Alternatively, in a favorable alternative form, the edge protection film can be introduced as a separate component, i.e., as a solid-phase material (e.g., film, adhesive film, etc.).

[0018] Hereafter, embodiments of the present invention will be described based on the attached figures. [Brief explanation of the drawing]

[0019] [Figure 1] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 2a] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 2b] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 2c] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 3a] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 3b] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 3c] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 4] This figure specifically illustrates the structure and manufacturing method of the electrode stack / separator stack according to the present invention. [Figure 5]This is a diagram specifically showing the structure and manufacturing of an electrode stack / separator stack according to the present invention.

[0020] In FIG. 1, a completed electrode stack / separator stack for a battery cell is shown. This has an anode A, a cathode K, and another anode A and cathode K in that order from bottom to top in the stacking direction, and these are each accompanied by a separator S disposed therebetween. The anode A is shown individually in FIGS. 2a to 2c. Thus, the anode A is a rectangular sheet cut portion composed of a substrate film 1. Both surfaces of the substrate film 1 are coated with an active material 3. The substrate film 1 is extended by an anode conductor piece 5 on one rectangular side facing outward.

[0021] According to FIGS. 3a to 3c, the cathode K is likewise a rectangular sheet cut portion, and this sheet cut portion is formed from a substrate film 1 with the active material 3 coated on both sides. The substrate film 1 of the cathode K is extended by a cathode conductor piece 7 on one rectangular side. Different from the anode A, the cathode K shown in FIGS. 3a to 3c is not provided as an individual sheet before the execution of the stacking process. Rather, the cathode K is a component of a laminated composite V together with the separator S, where the separator S is pressure - and heat - laminated on both sides onto the cathode K.

[0022] In the completed electrode stack / separator stack (FIG. 1), all the anode conductor pieces 5 protrude from the left - hand stack side surface, while on the other hand, all the cathode conductor pieces 7 protrude from the right - hand stack side surface.

[0023] As can be further seen from FIG. 1, the anode A is dimensioned, for example, 1 to 3 mm larger than the cathode K by the circumferential oversize portion a. This enables the overlap between the anode A and the cathode K to be ensured despite inaccurate placement. Further, the separator S and the anode A are realized as a common sheet cutting part, that is, the separator S and the anode A, excluding the anode conductor piece 5, have the same area and the same contour. Thus, in the electrode stack / separator stack (FIG. 1), the corners and edges of the anode A are aligned in the stacking direction with the corners and edges of the separator S.

[0024] In the laminated composite V, the two separators S project from the cathode K with a projection that is the same as the oversize portion a. In this way, an edge-side gap 9 defined by the separator projection a and the cathode K is formed. The edge-side gap 9 is completely filled by the edge protection film 11. This has the same material thickness as the cathode K when observed in the thickness direction of the laminated composite V. The two separators S are each formed with an adhesive layer 13, by which the separator S is laminated onto the cathode K under pressure and heating in the lamination process, thereby obtaining the laminated composite V.

[0025] The edge protection film 11 forms mechanical protection for the corners and edges of the laminated composite V. Further, the edge protection film 11 acts as an electrical insulator to prevent direct contact connection between the anode A and the cathode K. Further, the edge protection film 11 improves the shape stability of the laminated composite V at its corners and edges.

[0026] The edge protection film 11 is made from a polymer material. To avoid undesirable material combinations between the active material binder, i.e., PVDF, and the edge protection film 11, the edge protection film 11 is also made from PVDF. This further ensures chemical resistance to the electrolyte in the battery cell. It should be emphasized that the present invention is not limited to the edge protection film 11 made of PVDF, and rather, it is possible to manufacture the edge protection film 11 from other suitable materials instead of PVDF.

[0027] The electrode stack / separator stack (Figure 1) is manufactured in a lamination process and a subsequent alignment process (Figures 4 and 5). In the lamination process, laminated composite V and anode A are stacked alternately. Then, in the alignment process (Figures 4 and 5), positional adjustment is performed, where the stack components, i.e., the laminated composite V and anode A, can be aligned in a line with other stack components using a slider 15. It should be emphasized that the present invention is not limited to the use of the slider 15 shown in the figures. Rather, alignment may be performed by gravity, thereby enabling self-centering alignment. Alternatively, the alignment function can also be realized using a diaphragm with a fixed stopper.

[0028] Using slider 15, an alignment force F acting laterally to the electrode stack / separator stack with respect to the stacking direction can also be applied, in some cases, under the influence of gravity.

[0029] This invention makes it possible to achieve impeccable stacking accuracy without relying on image processing and manipulation devices. Using inexpensive technology (i.e., slider 15), stacking accuracy can be raised to a high level. Furthermore, stacking accuracy can be adjusted after the stacking process, i.e., during the alignment process. [Explanation of symbols]

[0030] 1. Substrate film 3 Active materials 5 Anode conductor pieces 7 Cathode Conductor Pieces 9. Edge gap 11 Edge Protection Film 13 Adhesive layer 15 Lateral stopper Anode K Cathode V Laminated composite F Alignment Power a. Oversized portion, separator protrusion

Claims

1. A method for manufacturing an electrode stack / separator stack for a battery cell, comprising at least an electrode (K) and a counter electrode (A), The electrode (K) is a component of a laminated composite (V) in which one separator (S) is laminated to each of the two sides of the electrode (K). The two separators (S) protrude from the electrode (K) on the edge side by their protruding portions (a). The edge-side gap (9) between the protruding portions (a) of the two separators (S) is completely filled by the edge protection film (11). The method for manufacturing the electrode stack / separator stack is: A lamination process in which the laminated composite (V) and the counter electrode (A) are not fixed and can be stacked on each other in the lamination direction, An alignment process wherein the laminated composite (V) and the counter electrode (A) can be aligned in a line with respect to each other in the stacking direction. Includes, By providing the edge protection film (11), the laminated composite (V) is configured in a shape-stable manner, thereby enabling damage-free repositioning of the laminated composite (V) in a direction lateral to the lamination direction. method.

2. The method according to claim 1, wherein each separator (S) has an adhesive layer (13), and the separator (S) can be laminated onto the electrode (K) in a lamination process using the adhesive layer (13), thereby forming the laminated composite (V).

3. The method according to claim 1, wherein the electrode (K) and / or the counter electrode (A) are formed from a substrate film (1), and one or both sides of the substrate film (1) are coated with an active material (3).

4. The laminated composite (V) is a rectangular planar cut section, On one side of the cut portion, i.e., on the side of the conductor piece, the substrate film (1) of the electrode (K) is extended laterally outward by the conductor pieces (5, 7), beyond the separator edge. The method according to claim 3, wherein the edge-side gap (9) filled by the edge protection film (11) extends continuously at least along the cut side opposite to the conductor piece (7) and along two sides of the laminated composite (V) perpendicular to the conductor piece side.

5. The method according to claim 4, wherein the edge-side gap (9) filled by the edge protection film (11) extends circumferentially along all of the cut side surfaces of the laminated composite (V), except for the conductive side surface.

6. The method according to claim 1, wherein the separator (S) and the counter electrode (A) are a joint sheet cutting portion, that is, except for the conductive piece (5) of the counter electrode (A), they have the same area and the same contour, so that the corners and edges of the counter electrode (A) can be aligned in a line with the corners and edges of the separator (S) in the stacking direction.

7. The method according to claim 1, wherein at least one lateral stopper (15) is used in the alignment process, and the lateral stopper allows stack components that are offset laterally with respect to the stacking direction, i.e., the laminated composite (V) or the counter electrode (A), to be aligned in a line with other stack components.

8. The method according to claim 1, wherein the edge protection film (11) can be attached to the laminated composite (V) in a coating process, and the viscous basic component of the edge protection film (11) can be directly applied to the edge-side gap (9) of the laminated composite (V).

Images