Electrode / separator stack for battery cell and method for manufacturing same

Abstract

The invention relates to an electrode / separator stack for a battery cell and a method for producing the same, in particular, the invention relates to an electrode / separator stack for a battery cell having at least one electrode, in particular a cathode (K), and a counter electrode, in particular an anode (A), the electrode (K) being a component (V) of a laminated composite, the invention relates to a laminated composite in which separators (S) are laminated on the electrode (K) on both sides, and wherein the two separators (S) protrude beyond the electrode (K) on the edge side with protrusions (a). According to the invention, the edge gap (9) between the two separator projections (a) is in particular completely filled with an edge protective film (11).

Description

Technical Field

[0001] The invention relates to an electrode / separator stack (sometimes referred to as an electrode / separator stack) for a battery cell (sometimes referred to as a battery cell) and to a method for producing such an electrode / separator stack. Background Art

[0002] The manufacture of such an electrode / separator stack can be carried out by a single sheet stack. In the case of a single sheet stack, the placement accuracy (Ablagegenauigkeit, sometimes referred to as placement accuracy) of the electrodes and separator sheets in the electrode / separator stack is very important for the safety and performance of the battery cell. Therefore, the electrochemical performance of the battery cell with a smaller electrode overlap decreases faster during operation. In addition, incorrect sheet placement can lead to direct contact between the anode and the cathode, which can trigger a short circuit and a battery cell failure. In order to improve the complete overlap of the anode and the cathode despite the placement inaccuracy, the anode in the electrode / separator stack can, for example, be circumferentially larger than the cathode by a margin (e.g., 1.5 mm), and the separator (Separator, sometimes referred to as a partition) can be larger than the anode by a margin.

[0003] The above-mentioned individual sheet stacking is carried out in a complex production process with the aid of a handling device, which obtains the coordinates of the individual sheet stack based on image processing, in which the position of each placed electrode / separator sheet is optically acquired and evaluated for each sheet placement to determine the placement accuracy.

[0004] In the case of such an optical acquisition of the placement accuracy, there is no provision for a position correction of the already placed electrode / separator sheets after the stacking process, so that placement errors are detected but can no longer be eliminated subsequently. In addition, the stacking process performed by means of image processing is highly complex in terms of measurement technology and can lead to system-induced position deviations of the individual sheets stacked in the electrode / separator stack.

[0005] From US2022 / 0148821A1, a battery cell is known, which has an internal element, which has a first main surface, a second main surface, a first side surface, a second side surface, a first end surface, and a second end surface. In addition, a first internal electrode extending to the first end surface, a second electrode extending to the second end surface, a separator layer arranged between the first electrode and the second electrode, and an electrolytic solution are provided. In addition, the first electrode is arranged at the first end surface, and the second electrode is arranged at the second end surface. The first electrode, the second electrode and the separator layer are assembled into a one-piece composite.

[0006] DE 10 2016 217 397 A1 discloses an electrode stack which is provided with an electrically insulating coating on at least one sheet edge. The coating is applied from a liquid phase and extends over the entire height of the electrode stack.

[0007] JP 5375263 B2 discloses a method and a device for producing a battery with a high battery power, in which a plurality of laminates composed of electrodes and separators are formed. Summary of the invention

[0008] The object of the present invention is to provide an electrode / separator stack and a method for producing such an electrode / separator stack in which the stacking process can be carried out more simply in terms of production technology and with greater positioning accuracy than in the prior art.

[0009] This object is achieved by the features described below.

[0010] The present invention starts from an electrode / separator stack for a battery cell, which is constructed of at least an electrode (especially a cathode) and a counter electrode (especially an anode). The electrode is a component of a laminated composite in which separators are laminated to the electrode on both sides. The two separators protrude beyond the electrode with a protrusion on the edge side. According to the present invention, the edge side gap between the two separator protrusions is preferably completely filled with an edge protection film. Observed in the thickness direction of the laminated composite, the edge protection film can have the same material thickness as the electrode. In this way, the edges and edges of the electrode are protected from external mechanical loads by means of the edge protection film. The edge protection film can provide a shape-stable stop surface during the orientation process performed at the completed electrode / separator stack, by means of which a damage-free lateral displacement of the electrode in the electrode / separator stack can be achieved. In addition, the edge protection film serves as an electrical insulator, by means of which the electrical safety of the battery cell is improved.

[0011] The electrode / separator stack according to the invention can be produced in the manner of an individual sheet stack in which the laminate composite and the counter electrode are stacked one on top of the other as individual sheets.

[0012] In one technical embodiment, each of the separators can have an adhesive layer, by means of which the separator can be laminated to the electrode during the lamination process, more precisely when forming a laminated composite. In this way, the two separators and the electrode arranged between them are already assembled into a one-piece structural unit before the stacking process is carried out, thereby increasing the stacking accuracy in the electrode / separator stack, more precisely compared to an electrode / separator stack in which the electrodes are stacked as individual sheets.

[0013] The electrode and / or the counter electrode are constructed from a substrate foil. The substrate foil is coated with an electrode active material on one or both sides. The active material has an adhesive, in particular a polymer adhesive, preferably PVDF. In order to avoid inappropriate material pairing (Material pairing, sometimes referred to as material pairing) between the active material and the edge protection film and, if necessary, the adhesive layer, not only the active material adhesive but also the edge protection film and, if necessary, the adhesive layer are constructed with the same material. That is, not only the adhesive layer but also the edge protection film has the same material structure as the active material adhesive. This ensures the resistance of the edge protection film to the electrolyte. In addition, it is ensured that the material pairing between the edge protection film and the active material adhesive is electrochemically stable or resistant.

[0014] A laminated composite consisting of two separators and an electrode arranged therebetween can be provided as a rectangular planar cut piece. At one of its cut sides (hereinafter referred to as the "conductor lug side"), the base foil of the electrode can extend outwardly beyond the edge of the separator in an upward direction with the conductor lug side (Ableiterfahne). The edge side gap filled with the edge protection film can extend continuously at least along the cut side facing away from the conductor lug side and along the two cut sides of the laminated composite perpendicular to the conductor lug side. No edge protection film is provided on the conductor lug side itself, so that the conductor lug can be led out of the composite. In this way, a thickening in terms of the height of the conductor lug (caused by the edge protection film) is avoided, which thickening is then noticed later. It is therefore advantageous that the edge protection film is only present at three of the four cut sides in total, so that no thickening can occur.

[0015] In order to achieve a complete overlap of the electrode (i.e. cathode) and the counterelectrode (i.e. anode) despite placement inaccuracies, the counterelectrode can preferably be dimensioned to be larger than the electrode by a margin, for example 1 to 3 mm. The counterelectrode and the separator can preferably be made as congruent sheet cuts. That is, the counterelectrode (except for its conductor lugs) is dimensioned to have the same area and the same contour as the separator, so that the corners and edges of the counterelectrode can be aligned flush with the corners and edges of the separator in the stacking direction.

[0016] The method for making an electrode / separator stack can be divided into a stacking process and a subsequent orientation process. In the stacking process, the laminated composite consisting of separators and electrodes and the counter electrodes are stacked one on top of the other according to the type of the single sheet stack. In the subsequent orientation process (Ausrichtprozess, sometimes called an alignment process), the laminated composite and the counter electrodes can be oriented flush with each other in the stacking direction. Due to the provision of the edge protection film according to the present invention, the laminated composite is designed to be stable in shape, thereby enabling the laminated composite to be non-destructively corrected in position transversely to the stacking direction. This shape-stable laminated composite also provides a stable abutment or a stable support base for adjacent counter electrodes, thereby enabling the position correction of the counter electrodes to be performed without damage. At least one transverse stop, in particular a slider, can preferably be used during the orientation process. With the transverse stop, it is possible to perform a position correction of a stack component (i.e., a laminated composite or a counter electrode) that is offset transversely to the stacking direction, i.e., an orientation flush with another stack component.

[0017] The edge protection film can be applied to the laminated composite in any suitable manner. For example, the edge protection film can be applied to the laminated composite in an application process in which the adhesive starting component of the edge protection film is applied directly into the edge gaps of the laminated composite. In a relatively advantageous alternative variant, the edge protection film can also be introduced as a separate component, i.e. as a solid phase material (e.g. foil, adhesive film, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Next, embodiments of the present invention will be described based on the accompanying drawings.

[0019] in:

[0020] Figures 1 to 5 Different views are shown in each case, based on which the structure and production of the electrode / separator stack according to the invention are explained. DETAILED DESCRIPTION

[0021] Figure 1 , a finished electrode / separator stack for a battery cell is shown. In the stacking direction, in the order from bottom to top, the electrode / separator stack has an anode A, a cathode K and a further anode A and cathode K, with a separator S arranged in between. Figures 2a to 2c The anode A is thus a rectangular sheet blank (blattzuschnitt, sometimes referred to as a sheet blank) which is constructed from a substrate foil 1. It is coated with active material 3 on both sides. The substrate foil 1 extends outwards at the sides of the rectangle with anode conductor tabs 5.

[0022] according to Figures 3a to 3cThe cathode K is also a rectangular sheet cutout made of a base foil 1, which is coated with active material 3 on both sides. The base foil 1 of the cathode K is extended with a cathode conductor lug 7 at the side of the rectangle. Figure 3a to Figure 3c The cathode K is not provided as an individual sheet before the stacking process is carried out. Instead, the cathode K together with the separator S is a component of a lamination composite V in which the separator S is laminated to the cathode K on both sides under pressure and heat.

[0023] In the completed electrode / separator stack ( Figure 1 ), all anode conductor tabs 5 protrude from the left stack side, while all cathode conductor tabs 7 protrude from the right stack side.

[0024] As from Figure 1 As is further known, the anode A is dimensioned to be larger than the cathode K by a circumferential margin a of, for example, 1 to 3 mm. This ensures that the anode A and the cathode K overlap despite placement inaccuracies. In addition, the separator S and the anode A are realized as congruent sheet cutouts; that is, the separator S and the anode A are of the same area and the same contour, except for the anode conductor lug 5, so that in the electrode / separator stack ( Figure 1 ) the corners and edges of the anode A are oriented flush with the corners and edges of the separator S in the stacking direction.

[0025] In the laminated composite V, the two separators S protrude beyond the cathode K with the same protrusion as the margin a. In this way, an edge-side gap 9 is formed, which is bounded by the separator protrusion a and the cathode K. The edge-side gap 9 is completely filled with an edge protection film 11. Viewed in the thickness direction of the laminated composite V, the edge protection film has the same material thickness as the cathode K. The two separators S are each constructed with an adhesive layer 13, by means of which the separators S are laminated to the cathode K under pressure and heat during the lamination process, resulting in a laminated composite V.

[0026] The edge protection film 11 provides mechanical protection for the corners and edges of the laminated composite V. Furthermore, the edge protection film 11 serves as an electrical insulator to prevent direct contact between the anode A and the cathode K. Furthermore, the edge protection film 11 increases the dimensional stability of the laminated composite V at its corners and edges.

[0027] The edge protection film 11 is made of a polymer material. In order to avoid an unsuitable material pairing between the active material binder (i.e. PVDF) and the edge protection film 11, the edge protection film 11 is also made of PVDF. This also ensures chemical resistance to the electrolyte in the battery cell. It should be emphasized that the present invention is not limited to an edge protection film 11 composed of PVDF; on the contrary, the edge protection film 11 can also be made of other suitable materials instead of PVDF.

[0028] Electrode / Separator Stack( Figure 1 ) during the stacking process and the subsequent orientation process ( Figure 4 and 5 ) is manufactured. In the stacking process, the laminate composite V and the anode A are stacked one on top of the other. Then in the orientation process ( Figure 4 and 5 ) is subjected to position correction, in which the stack components (i.e. the laminated composite V and the anode A) can be aligned flush with the other stack components by means of a slide 15. It should be emphasized that the invention is not limited to the use of the slide 15 shown in the figure. Instead, the alignment can also be carried out via gravity and thus in a self-centering manner. Alternatively to this, the alignment function can also be realized by means of a vibrating plate with a fixed stop.

[0029] If necessary, an orientation force F acting on the electrode / separator stack transversely to the stacking direction can also be applied under the effect of gravity by means of the slide 15 .

[0030] With the invention, perfect stacking accuracy can be achieved independently of image processing and operating devices. The stacking accuracy is increased to a high level by means of cost-effective technology (i.e. the slide 15). In addition, the stacking accuracy can be adjusted after the stacking process, i.e. during the orientation process.

[0031] Reference numerals list

[0032] 1 Base foil

[0033] 2 Active Materials

[0034] 5 Anode conductor lug

[0035] 7 Cathode conductor lug

[0036] 9 Edge side clearance

[0037] 11 Edge protection film

[0038] 13 Adhesive layer

[0039] 15 lateral stop

[0040] A Anode

[0041] K cathode

[0042] V laminated composite parts

[0043] F Orientation force

[0044] a margin, separator protrusion

Claims

1. An electrode / separator stack for a battery cell, comprising at least one electrode, in particular a cathode (K), and a counter electrode, in particular an anode (A), wherein the electrode (K) is a component of a laminated composite (V), in which a separator (S) is laminated onto the electrode (K) on both sides, and wherein two separators (S) protrude beyond the electrode (K) at the edge with a projection (a), characterized in that The edge gap (9) between two separator projections (a) is in particular completely filled with an edge protection film (11), and in particular, viewed in the thickness direction of the laminate composite (V), the edge protection film (11) and the electrode (K) have the same material thickness.

2. The electrode / separator stack according to claim 1, characterized in that Each of the separators (S) has an adhesive layer (13), by means of which the separators (S) can be laminated onto the electrode (K) in a lamination process, to be more precise when forming the lamination composite (V).

3. The electrode / separator stack according to claim 1 or 2, characterized in that The electrode (K) and / or the counter electrode (A) is constructed from a substrate foil (1) to which an active material (3) is applied on one or both sides, and in particular the active material (3) has a binder, in particular a polymer binder, preferably PVDF, and in particular the active material binder, the edge protection film (11) and / or the adhesive layer (13) are constructed from the same material.

4. An electrode / separator stack according to any one of the preceding claims, characterized in that The laminated composite (V) is a rectangular planar cut-out, and at one of its cut-out sides, namely the conductor lug side, the base foil (1) of the electrode (K) extends outwardly beyond the edge of the separator in the conductor lug (5, 7) side direction, and the edge side gap (9) filled with the edge protection film (11) extends continuously at least along the cut-out side facing away from the conductor lug (7) and in particular along both sides of the laminated composite (V) perpendicular to the conductor lug side.

5. The electrode / separator stack according to claim 4, characterized in that The edge-side gap (9) filled with the edge protection film (11) extends circumferentially along all cut-out sides of the laminate composite (V) except for the conductor lug side.

6. An electrode / separator stack according to any one of the preceding claims, characterized in that The separator (S) and the counter electrode (A) are congruent sheet cut pieces, that is, they have the same area and contour except for the conductor terminal (5) of the counter electrode (A), so that the corners and edges of the counter electrode (A) can be oriented flush with the corners and edges of the separator (S) in the stacking direction.

7. An electrode / separator stack according to any one of the preceding claims, characterized in that The method for producing the electrode / separator stack comprises a stacking process, in which the laminated composite (V) and the counter electrode (A) can be stacked loosely one on top of the other in the stacking direction, and an orientation process, in which the laminated composite (V) and the counter electrode (A) can be oriented flush with one another in the stacking direction.

8. The electrode / separator stack according to claim 7, characterized in that During the alignment process, at least one transverse stop (15), in particular a slide, is used, by means of which a stack component offset transversely to the stacking direction, namely the laminate composite (V) or the counter electrode (A), can be aligned flush with other stack components.

9. An electrode / separator stack according to any one of the preceding claims, characterized in that The edge protection film (11) can be applied to the laminating composite (V) in a coating process in which the adhesive starting component (11) of the edge protection film can be applied directly into the edge-side gaps (9) of the laminating composite (V).

10. A method for producing an electrode / separator stack for a battery cell, in particular according to any of the preceding claims, with at least one electrode, in particular a cathode (K), and a counter electrode, in particular an anode (A), wherein the electrode (K) is a component of a laminated composite (V), in which separators (S) are laminated onto the electrode (K) on both sides, and wherein two separators (S) protrude beyond the electrode (K) at the edge side with a projection (a), characterized in that The edge gap (9) between two separator projections (a) is in particular completely filled with an edge protection film (11), and in particular, viewed in the thickness direction of the laminate composite (V), the edge protection film (11) and the electrode (K) have the same material thickness.

Images