Method for manufacturing battery cell
The battery cell design addresses the issue of exposed edges by using lid materials to cover the exterior film edges, enhancing safety through prevention of short-circuiting.
Patent Information
- Application Number
- JP2025188131
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-01-27
AI Technical Summary
Existing battery cells face issues with exposed edges of the exterior film leading to potential short-circuiting due to conductive elements within the film.
The battery cell design incorporates lid materials that cover the edges of the exterior film, preventing exposure and potential short-circuiting by using convex portions on the lid members to encase the film ends.
Prevents exposure of the exterior film edges, thereby avoiding short-circuiting risks and ensuring safe operation of the battery cell.
Smart Images
Figure 2026012942000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a battery cell. [Background technology]
[0002] In recent years, various structures of battery cells, such as lithium-ion secondary battery cells, have been developed. For example, the battery cells described in Patent Documents 1 and 2 include a battery element, two lid members, and an exterior film. The two lid members cover both longitudinal ends of the battery element. The exterior film is wrapped around the battery element in the longitudinal direction. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] International Publication No. 2021 / 157731 Summary of the Invention [Problem to be solved by the invention]
[0004] For example, in the battery cell described in Patent Document 1, when the exterior film is wrapped around the lid, the edges of the exterior film are exposed. When the edges of the exterior film are exposed, it can be difficult to prevent short-circuiting of the exterior film via conductors such as conductive sheets included in the exterior film.
[0005] One example of an object of the present invention is to suppress exposure of the edge of an exterior film. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]
[0006] One aspect of the present invention is as follows. [1] A battery element; a tab electrically connected to the battery element; a cover material that covers an end of the battery element and through which the tab is pulled out; an exterior film wrapped at least partially around the battery element; Equipped with At least a portion of the lid material covers at least a portion of the edge of the exterior film. [2] The battery cell according to [1], wherein at least a portion of the lid material covers at least a portion of the outer circumferential surface of the exterior film. [3] The battery cell according to [1] or [2], further comprising another lid member that covers another end portion of the battery element opposite to the end portion. [Effects of the Invention]
[0007] According to the above aspect of the present invention, it is possible to prevent the end portion of the exterior film from being exposed. [Brief explanation of the drawings]
[0008] [Figure 1] FIG. 2 is a front perspective view of a battery cell according to the embodiment. [Figure 2] FIG. 2 is an enlarged front perspective view of a portion of a battery cell according to an embodiment. [Figure 3] FIG. 2 is a right side view of the battery cell according to the embodiment. [Figure 4] FIG. 3 is a cross-sectional view of FIG. 2 taken along the line AA. [Figure 5] FIG. 5 is a diagram showing a modification of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION
[0009] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and descriptions thereof will be omitted as appropriate.
[0010] Fig. 1 is a front perspective view of a battery cell 10 according to an embodiment. Fig. 2 is an enlarged front perspective view of a portion of the battery cell 10 according to an embodiment. Fig. 3 is a right side view of the battery cell 10 according to an embodiment. Fig. 4 is a schematic cross-sectional view taken along line AA in Fig. 2. For the sake of explanation, Fig. 3 shows an exterior film 300 in a see-through state.
[0011] For the sake of explanation, each figure is labeled with an X direction, a Y direction, and a Z direction. The X direction indicates the front-to-rear direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery cell 10. The Z direction is perpendicular to both the X direction and the Y direction. The Z direction indicates the up-to-down direction of the battery cell 10. The direction indicated by the arrow indicating the X direction, the direction indicated by the arrow indicating the Y direction, and the direction indicated by the arrow indicating the Z direction are the rearward, leftward, and upward directions, respectively. However, the relationships between the X direction, Y direction, Z direction, front-to-rear direction, left-to-right direction, and up-to-down direction of the battery cell 10 are not limited to this example.
[0012] The white circle with an X indicating the X, Y or Z direction indicates that the direction from the front of the paper to the back is the direction indicated by the arrow indicating that direction.
[0013] The battery cell 10 includes a battery element 100, a positive electrode tab 110, a negative electrode tab 120, a front cover member 210, a rear cover member 220, and an exterior film 300. The exterior film 300 has a wound portion 302 and a pulled-out portion 304.
[0014] The battery element 100 has a substantially rectangular parallelepiped shape. The longitudinal direction of the battery element 100 is substantially parallel to the X direction. The length of the battery element 100 in the X direction is not limited to, but is, for example, 300 mm to 500 mm, and preferably 450 mm or less. The lateral direction of the battery element 100 is substantially parallel to the Z direction. The length of the battery element 100 in the Z direction is not limited to, but is, for example, 90 mm to 130 mm, and preferably 120 mm or less. The thickness direction of the battery element 100 is substantially parallel to the Y direction. The thickness of the battery element 100 in the Y direction is not limited to, but is, for example, 20 mm to 50 mm, and preferably 45 mm or less. However, the shape of the battery element 100 is not limited to this example.
[0015] The battery element 100 includes at least one positive electrode (not shown), at least one negative electrode (not shown), and at least one separator (not shown). For example, multiple positive electrodes and multiple negative electrodes are alternately stacked in the Y direction. At least a portion of the separator is located between adjacent positive electrodes and negative electrodes in the Y direction. For example, multiple sheet-like separators may each be located between adjacent positive electrodes and negative electrodes in the Y direction. Alternatively, a single sheet-like separator may have a zigzag shape that passes through the region between adjacent positive electrodes and negative electrodes in the Y direction. Alternatively, the positive electrode, negative electrode, and separator may be wound so that the separator is located between the positive electrode and negative electrode. In one example, the positive electrode, negative electrode, and separator are wound with both surfaces of one of the positive electrode and negative electrode covered by the separator. In another example, a stack including multiple unit stacks each including a positive electrode, a separator, and a negative electrode in this order may be wound. However, the winding structure of the positive electrode, negative electrode, and separator is not limited to these examples.
[0016] The positive electrode tab 110 is disposed in front of the battery element 100. The rear end of the positive electrode tab 110 is electrically connected to the positive electrode current collector 102a. The positive electrode current collector 102a is drawn out forward from the positive electrode of the battery element 100. In this way, the positive electrode tab 110 is electrically connected to the positive electrode of the battery element 100.
[0017] The negative electrode tab 120 is disposed at the rear of the battery element 100. The front end of the negative electrode tab 120 is electrically connected to the negative electrode current collector 104a. The negative electrode current collector 104a is drawn out rearward from the negative electrode of the battery element 100. In this way, the negative electrode tab 120 is electrically connected to the negative electrode of the battery element 100.
[0018] The front cover member 210 covers the front end portion of the battery element 100. The front cover member 210 is made of, for example, resin, metal, or the like. The front end portion of the positive electrode tab 110 is pulled out from the front surface of the front cover member 210. When viewed from the front, the front cover member 210 has a substantially rectangular shape. When viewed from the front, the longitudinal direction of the front cover member 210 is substantially parallel to the Z direction, and the lateral direction of the front cover member 210 is substantially parallel to the Y direction.
[0019] The rear cover member 220 covers the rear end portion of the battery element 100. The rear cover member 220 is made of, for example, resin, metal, or the like. The rear end portion of the negative electrode tab 120 is pulled out from the rear surface of the rear cover member 220. When viewed from the rear, the rear cover member 220 has a substantially rectangular shape. When viewed from the rear, the longitudinal direction of the rear cover member 220 is substantially parallel to the Z direction, and the lateral direction of the rear cover member 220 is substantially parallel to the Y direction.
[0020] As shown in FIGS. 1 and 2 , the wound portion 302 has a generally cylindrical shape that opens both forward and backward. The front cover member 210 is disposed inside the front opening of the wound portion 302, excluding a front protrusion 212 (described later). The rear cover member 220 is disposed inside the rear opening of the wound portion 302, excluding a rear protrusion 222 (described later). The wound portion 302 is wound around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction by one turn. The front cover member 210, the rear cover member 220, and the wound portion 302 thereby form a storage space 500 that stores the battery element 100. The storage space 500 contains the battery element 100 and an electrolyte (not shown). The manner in which the wound portion 302 wraps around the battery element 100 is not limited to the above-described example.
[0021] The outer peripheral surface of the front lid member 210 in the X direction and the inner peripheral surface of the front opening of the wound portion 302 in the X direction are joined to each other by, for example, heat fusion, thereby forming the front sealing portion 510.
[0022] The outer peripheral surface of the rear lid member 220 in the X direction and the inner peripheral surface of the rear opening of the wound portion 302 in the X direction are joined to each other by, for example, heat sealing, thereby forming the rear sealing portion 520.
[0023] As shown in FIGS. 1 and 2 , the pull-out portion 304 is pulled out from the upper left corner of the wound portion 302 of the battery element 100 when viewed from the front. Specifically, as shown in FIG. 2 , the pull-out portion 304 includes a first pull-out portion 304a and a second pull-out portion 304b. The first pull-out portion 304a is pulled out from one of the circumferential ends of the wound portion 302 in the X direction. The second pull-out portion 304b is pulled out from the other of the circumferential ends of the wound portion 302 in the X direction. The first pull-out portion 304a and the second pull-out portion 304b are joined to each other by, for example, heat fusion. This forms a side sealing portion 530 when viewed from the front. The pull-out portion 304 is folded along the top surface of the battery element 100. However, the pull-out portion 304 does not have to be folded. The folding shape of the pull-out portion 304 is not limited to the shape described in the embodiment.
[0024] 1, 2, and 4, a front convex portion 212 is provided on the outer peripheral surface of the front lid member 210. The front convex portion 212 is provided on the entire outer peripheral surface of the front lid member 210. However, the front convex portion 212 may be provided on only a part of the entire outer peripheral surface of the front lid member 210. The front convex portion 212 is located in front of the front end portion of the exterior film 300. As a result, the front convex portion 212 covers the front end portion of the exterior film 300. Therefore, the front convex portion 212 can prevent the front end portion of the exterior film 300 from being exposed. Therefore, even if a conductor such as a conductive sheet included in the exterior film 300 is exposed from the front end portion of the exterior film 300, it is possible to prevent the exterior film 300 from short-circuiting via the conductor.
[0025] 1, a rear convex portion 222 is provided on the outer peripheral surface of the rear lid member 220, similar to the outer peripheral surface of the front lid member 210. The rear convex portion 222 covers the rear end portion of the exterior film 300, similar to the front convex portion 212. Therefore, the rear convex portion 222 can prevent the rear end portion of the exterior film 300 from being exposed. Therefore, even if a conductor such as a conductive sheet included in the exterior film 300 is exposed from the rear end portion of the exterior film 300, it is possible to prevent the exterior film 300 from shorting out via the conductor.
[0026] In the embodiment, both the front convex portion 212 and the rear convex portion 222 are provided. However, only one of the front convex portion 212 and the rear convex portion 222 may be provided.
[0027] Next, an example of a method for manufacturing the battery cell 10 according to the embodiment will be described. In this example, the battery cell 10 according to the embodiment is manufactured as follows.
[0028] First, the battery element 100 is manufactured. The battery element 100 has at least one positive electrode, at least one negative electrode, and at least one separator.
[0029] Next, the positive electrode tab 110 and the front cover member 210 are joined together. Similarly, the negative electrode tab 120 and the rear cover member 220 are joined together. Next, the positive electrode tab 110 and the positive electrode current collector 102a are joined together. Similarly, the negative electrode tab 120 and the negative electrode current collector 104a are joined together. However, the positive electrode tab 110 and the positive electrode current collector 102a may be joined together first, and then the positive electrode tab 110 and the front cover member 210 may be joined together. Similarly, the negative electrode tab 120 and the negative electrode current collector 104a may be joined together first, and then the negative electrode tab 120 and the rear cover member 220 may be joined together.
[0030] Next, the exterior film 300 is wrapped around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction once. This forms a wrapped portion 302. The excess length of the exterior film 300 is then pulled out as a pulled-out portion 304. In this state, the front convex portion 212 is located in front of the front end of the exterior film 300. As a result, the front end of the exterior film 300 is covered by the front convex portion 212. Furthermore, the rear convex portion 222 is located behind the rear end of the exterior film 300. As a result, the rear end of the exterior film 300 is covered by the rear convex portion 222.
[0031] Next, the outer peripheral surface of the front lid member 210 in the X direction and the inner peripheral surface of the front opening of the wound portion 302 in the X direction are joined together by heat fusion, thereby forming the front sealed portion 510. Next, the outer peripheral surface of the rear lid member 220 in the X direction and the inner peripheral surface of the rear opening of the wound portion 302 in the X direction are joined together by heat fusion, thereby forming the rear sealed portion 520.
[0032] Next, an electrolyte is injected into the accommodation space 500 through the gap between the first drawn portion 304a and the second drawn portion 304b. Next, the accommodation space 500 is evacuated through the gap between the first drawn portion 304a and the second drawn portion 304b. Next, the first drawn portion 304a and the second drawn portion 304b are joined by heat fusion to form the side sealing portion 530. This vacuum-seals the accommodation space 500.
[0033] The method for vacuum-sealing the storage space 500 is not limited to the above example. In another example, first, the first drawn-out portion 304a and the second drawn-out portion 304b are joined by heat fusion to form the side sealing portion 530. Next, electrolyte is injected into the storage space 500 through an injection hole provided in at least one of the front cover member 210 and the rear cover member 220. Next, a vacuum is drawn in the storage space 500 through the injection hole. Next, the injection hole is closed with a predetermined cover member.
[0034] Next, the side sealing portion 530 is folded along the top surface of the battery element 100 .
[0035] In this manner, the battery cell 10 is manufactured.
[0036] FIG. 5 is a diagram showing a modification of FIG.
[0037] The front cover member 210A of the battery cell 10A according to the modified example has a front covering portion 212A. The front covering portion 212A covers the front end of the exterior film 300 and a portion of the outer circumferential surface of the exterior film 300 near the front end. In particular, the front covering portion 212A covers the upper surface of the side sealing portion 530 above the accommodation space 500 and near the front end of the exterior film 300. When the front covering portion 212A covers at least a portion of the front end of the exterior film 300, even if a conductor such as a conductive sheet included in the exterior film 300 is exposed from the front end of the exterior film 300, a short circuit of the exterior film 300 via the conductor can be suppressed. When the front covering portion 212A covers at least a portion of the outer circumferential surface of the exterior film 300, the position of the front end of the exterior film 300 can be fixed by the front covering portion 212A.
[0038] In one example, the front covering portion 212A can be formed by deforming the front convex portion 212 according to the embodiment. For example, after completing all steps of the manufacturing method for the battery cell 10 according to the embodiment, the front convex portion 212 is crushed while applying heat to the front convex portion 212, causing the material constituting the front convex portion 212 to flow rearward. This causes the material constituting the front convex portion 212 to cover not only the front end portion of the exterior film 300 but also the outer peripheral surface of the exterior film 300. In particular, if the side sealing portion 530 is folded along the battery element 100 before deforming the front convex portion 212, the outer surface of the side sealing portion 530 can be covered by the front covering portion 212A.
[0039] The structure of the front lid member 210A has been described in the example shown in Figure 5. The structure of the front lid member 210A in Figure 5 can be similarly applied to the rear lid member.
[0040] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.
[0041] For example, in the embodiment, the positive electrode tab 110 and the negative electrode tab 120 are arranged on opposite sides of the battery element 100 in the X direction. However, both the positive electrode tab 110 and the negative electrode tab 120 may be arranged on only one of the front and rear sides of the battery element 100 in the X direction. In this case, the front end and rear end of the battery element 100 are covered by, for example, two lid materials. Alternatively, only the side of the battery element 100 from which the positive electrode tab 110 and the negative electrode tab 120 are pulled out may be covered by a lid material. In this example, an exterior film 300 may be sealed on the side of the battery element 100 opposite the lid material and folded along the battery element 100. [Explanation of symbols]
[0042] 10,10A battery cell 100 Battery Elements 102a Positive electrode current collector 104a Negative electrode current collector 110 Positive electrode tab 120 Negative electrode tab 210,210A Front lid material 212 Front convex part 212A Front covering part 220 Rear lid material 222 Rear convex part 300 exterior film 302 Wrapping part 304 Drawer part 304a 1st drawer part 304b 2nd drawer part 500 storage spaces 510 Front sealing part 520 Rear sealing part 530 Side sealing part
Claims
1. a step of preparing a battery element, a tab electrically connected to the battery element, a lid material covering an end of the battery element, from which the tab is pulled out, and having a convex portion on its outer circumferential surface, and an exterior film at least a portion of which is wrapped around the battery element and the lid material, and whose end is covered by the convex portion; a step of covering an outer circumferential surface of the exterior film with a covering portion formed by crushing the convex portion while applying heat to the convex portion to deform the convex portion; A method for manufacturing a battery cell, comprising:
2. 2. The method for manufacturing a battery cell according to claim 1, wherein the step of preparing the battery element, the tab, the lid material, and the exterior film includes a step of joining an outer peripheral surface of the lid material and an inner peripheral surface of the exterior film by thermal fusion.
3. the step of preparing the battery element, the tab, the lid material, and the exterior film includes a step of joining pulled-out portions of the exterior film pulled out from wound portions of the exterior film wrapped around the battery element and the lid material to form a sealing portion; The method for manufacturing a battery cell according to claim 1 or 2, wherein the step of covering the outer peripheral surface of the exterior film with the covering portion includes the step of covering the sealing portion of the exterior film with the covering portion.
Citation Information
Patent Citations
Energy storage device and method for manufacturing energy storage device
WO2021157731A1