Energy storage cell
The innovative design of the current collector foil with a covering and exposed area in the storage battery cell addresses the challenge of electrolyte shortage and secure connections, ensuring efficient electrolyte flow and impregnation during high-rate charging and discharging.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2026-03-02
- Publication Date
- 2026-05-15
AI Technical Summary
Existing tabless type storage battery cells face challenges in securely connecting the current collector foil and plate while preventing electrolyte shortage, especially during high-rate charge and discharge.
The design includes a current collector foil with an active material layer that has a main region and an end region with bent tabs forming a covering and exposed area, ensuring connection to the collector plate and allowing electrolyte re-impregnation during high-rate charging and discharging.
This design effectively suppresses electrolyte shortage in the electrode body while maintaining secure connections, facilitating efficient electrolyte flow and impregnation.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a storage battery cell.
Background Art
[0002] Japanese Patent Application Laid-Open No. 10-162854 discloses a cylindrical battery including an electrode group formed of a wound body in which a strip-shaped positive electrode plate and a negative electrode plate are wound in a spiral shape via a separator, a disc-shaped current collector, a battery case, and an electrolytic solution. The positive electrode plate and the negative electrode plate each have a conductive end edge protruding outward from an upper and lower end in a vertical direction, and this conductive end edge is connected to the current collector.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a so-called tabless type storage battery cell as described in Japanese Patent Application Laid-Open No. 10-162854, it is required to securely connect the tab of the current collector foil and the current collector plate. Further, especially during high-rate charge and discharge, since the electrolytic solution flows out from the electrode body, there is a concern that the electrolytic solution may be insufficient in the electrode body.
[0005] An object of the present disclosure is to provide a storage battery cell capable of suppressing a shortage of electrolytic solution in an electrode body while ensuring connection between a current collector foil and a current collector plate.
Means for Solving the Problems
[0006] A storage cell according to one aspect of the present disclosure comprises an electrode body having a positive electrode sheet, a negative electrode sheet, and a separator, the positive electrode sheet and the negative electrode sheet being wound around the separator, an electrode body formed by a winding, a current collector plate connected to the electrode body, a cell case housing the electrode body and the current collector plate, and an electrolyte contained within the cell case, wherein each of the positive electrode sheet and the negative electrode sheet has a current collector foil and an active material layer provided on the surface of the current collector foil, the current collector foil having the active material layer and being connected to the electrode body in the radial direction The electrode body has a main region arranged to overlap, and an end region formed outside the main region in the axial direction of the electrode body, where the active material layer is not provided. The active material layer includes a layer end formed at the end in the axial direction, and the end region is separated from each other in the circumferential direction of the electrode body and has a plurality of tabs bent relative to the main region, the plurality of tabs being arranged to form a covering region that covers a part of the layer end and an exposed region that exposes the rest of the layer end, and the current collector plate is connected to the covering region. [Effects of the Invention]
[0007] According to this disclosure, it is possible to provide an energy storage cell that can suppress electrolyte shortage in the electrode body while ensuring connection between the current collector foil and the current collector plate. [Brief explanation of the drawing]
[0008] [Figure 1] This is a schematic cross-sectional view showing a storage cell in one embodiment of the present disclosure. [Figure 2] This is a schematic plan view showing the electrode assembly. [Figure 3] This is a schematic front view showing the positive electrode sheet before winding. [Figure 4] This is a schematic plan view showing a modified electrode assembly. [Figure 5] This is a schematic plan view showing a modified electrode assembly. [Figure 6] This is a schematic plan view showing a modified electrode assembly. [Figure 7] This is a schematic plan view showing a modified electrode assembly. [Modes for carrying out the invention]
[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.
[0010] Figure 1 is a schematic partial cross-sectional view showing a storage cell in one embodiment of the present disclosure. This storage cell 1 is preferably mounted in a vehicle.
[0011] As shown in Figure 1, the energy storage cell 1 comprises an electrode body 100, a cell case 200, an external terminal 300, a positive electrode current collector plate 410, a negative electrode current collector plate 420, an insulating member 500, and an electrolyte (not shown).
[0012] The electrode body 100 includes a positive electrode sheet 110, a negative electrode sheet 120, and a separator 130. The electrode body 100 is composed of a wound body in which the positive electrode sheet 110 and the negative electrode sheet 120 are wound around a winding core A via the separator 130.
[0013] Figure 3 is a schematic front view showing the positive electrode sheet before winding. As shown in Figures 1 and 3, the positive electrode sheet 110 has a positive electrode current collector foil 112 and a positive electrode active material layer 114. In Figure 3, the positive electrode active material layer 114 is shown with a dot pattern.
[0014] The positive electrode current collector foil 112 is made of a metal such as aluminum. The positive electrode current collector foil 112 has a main region 112a and an end region 112b.
[0015] The main region 112a is the region of the positive electrode current collector foil 112 in which the positive electrode active material layer 114 is provided. As shown in Figure 1, the main regions 112a are arranged to overlap each other in the radial direction (left-right direction in Figure 1) of the electrode body 100.
[0016] The end region 112b is the region of the positive electrode current collector foil 112 where the positive electrode active material layer 114 is not provided. As shown in FIG. 1, the end region 112b is formed outside (the upper side in FIG. 1) the main region 112a in the axial direction (the vertical direction in FIG. 1) of the electrode body 100.
[0017] The end region 112b has a plurality of tabs 112b1 (see FIG. 3) separated from each other in the circumferential direction of the electrode body 100. As shown in FIG. 1, each tab 112b1 is bent with respect to the main region 112a. Specifically, each tab 112b1 is tilted inward in the radial direction. The upper surface of each tab 112b1 forms a substantially flat surface. The positive electrode current collector plate 410 is connected to each tab 112b1 by welding or the like.
[0018] The negative electrode sheet 120 has a negative electrode current collector foil 122 made of a metal such as copper, and a negative electrode active material layer 124 provided on the surface of the negative electrode current collector foil 122.
[0019] The structure of the negative electrode current collector foil 122 is substantially the same as the structure of the positive electrode current collector foil 112. Therefore, the description of the negative electrode current collector foil 122 is simplified. That is, the negative electrode current collector foil 122 has a main region 122a provided with the negative electrode active material layer 124, and an end region 122b formed outside (the lower side in FIG. 1) the main region 122a in the axial direction. The end region 122b has a plurality of tabs separated from each other in the circumferential direction, and each tab is tilted inward in the radial direction. The negative electrode current collector plate 420 is connected to each tab by welding or the like.
[0020] The separator 130 is disposed between the positive electrode sheet 110 and the negative electrode sheet 120. More specifically, the separator 130 is disposed only between the main region 112a of the positive electrode sheet 110 and the main region 122a of the negative electrode sheet 120 adjacent to each other in the radial direction. The separator 130 is made of an insulating material and allows the permeation of ions.
[0021] The cell case 200 houses the electrode body 100. An electrolyte solution (not shown) is contained inside the cell case 200. The cell case 200 is sealed. The cell case 200 is made of a metal such as aluminum. The cell case 200 has a cylindrical section 210, a top wall 220, and a bottom wall 230.
[0022] The cylindrical portion 210 surrounds the outer surface of the electrode body 100.
[0023] The top wall 220 is connected to the upper end of the cylindrical portion 210. A through hole for inserting the external terminal 300 is formed in the center of the top wall 220.
[0024] The bottom wall 230 is connected to the lower end of the cylindrical portion 210. More specifically, the bottom wall 230 is connected to the lower end of the cylindrical portion 210 via an insulating member 235. The bottom wall 230 is in contact with the negative electrode current collector plate 420.
[0025] The external terminal 300 is formed above the top wall 220. In this embodiment, the external terminal 300 constitutes the positive external terminal. The cell case 200 constitutes the negative external terminal.
[0026] The insulating member 500 insulates the cell case 200 and the external terminals 300. The insulating member 500 has an upper insulating portion 510 and a lower insulating portion 520.
[0027] The upper insulating portion 510 is provided on the upper surface of the top wall 220. The upper insulating portion 510 is interposed between the upper surface of the top wall 220 and the external terminal 300.
[0028] The lower insulating section 520 is provided on the lower surface of the top wall 220. The lower insulating section 520 is interposed between the positive electrode current collector plate 410 and the cell case 200.
[0029] Figure 2 is a schematic plan view of the electrode body. Since the lower surface of the electrode body 100 has a structure that substantially corresponds to the upper surface of the electrode body 100, the structure of the upper surface of the electrode body 100 will be used as an example in the following explanation.
[0030] As shown in Figure 2, the multiple tabs 112b1 are arranged to form a covered area R10 and an exposed area R20. The covered area R10 is the area that covers a portion of the layer ends 114a, 124a (see Figure 1), which are formed by the ends of each active material layer 114, 124 in the axial direction. The exposed area R20 is the area that exposes the remainder of the layer ends 114a, 124a (the area other than the area covered by the covered area R10).
[0031] In the example shown in Figure 2, the multiple tabs 112b1 are arranged to form multiple (six) covering regions R10 that are spaced apart in the circumferential direction of the electrode body 100. Each covering region R10 extends radially from the outer end of the electrode body 100 to the inner end of the electrode body 100 in the radial direction. The inner end of each covering region R10 in the radial direction is located midway between the outer and inner ends of the electrode body 100 in the radial direction.
[0032] The exposed region R20 includes an annular exposed region R22 that is connected in an annular shape in the circumferential direction of the electrode body 100. The annular exposed region R22 is formed inside the radially covered region R10. The shape of the exposed region R20 may differ between the upper and lower surfaces of the electrode body 100. For example, the area of the exposed region R20 on the lower surface of the electrode body 100 may be larger than the area of the exposed region R20 on the upper surface of the electrode body 100.
[0033] As described above, in the energy storage cell 1 of this embodiment, the connection between each current collector foil 112, 122 and each current collector plate 410, 420 is ensured in the covering region R10, and the electrolyte that flows out from the electrode body 100 during high-rate charging and discharging is re-impregnated into the electrode body 100 through the exposed region R20, thereby suppressing a shortage of electrolyte in the electrode body 100.
[0034] Furthermore, during the manufacturing of the energy storage cell 1, after the electrode body 100 is housed in the cell case 200, when electrolyte is supplied into the cell case 200, the electrolyte effectively impregnates the electrode body 100 through the exposed region R20.
[0035] In the above embodiment, as shown in Figures 4 and 5, the covering region R10 may be formed in a shape that extends radially from the outer end to the inner end of the electrode body 100. In this embodiment, the degree of freedom in selecting the connection point between the covering region R10 and each current collector plate 410, 420 is increased.
[0036] Furthermore, as shown in Figures 6 and 7, the covering region R10 may include an annular covering region R12 that is connected in a ring shape in the circumferential direction. In other words, the multiple tabs 112b1 may be arranged so as to form an annular covering region R12. In this embodiment, the outflow of electrolyte from the electrode body 100 during high-rate charging and discharging is effectively blocked by the annular covering region R12, and the electrolyte that has flowed out from the electrode body 100 is re-impregnated into the electrode body 100 through the exposed region R20. Therefore, the shortage of electrolyte in the electrode body 100 is more reliably suppressed.
[0037] In the example shown in Figure 6, the annular covering region R12 is formed inside the radially exposed region R20. The annular covering region R12 covers the winding core A. In this embodiment, a relatively large area of the exposed region R20 is secured, allowing for smooth flow of electrolyte into the electrode body 100 through the exposed region R20.
[0038] In the example shown in Figure 7, the annular covering region R12 is formed outside the radially exposed region R20. In this embodiment, the exposed region R20 is formed on the winding core A side of the electrode body 100, where stress concentration and heat buildup are likely to occur, thus facilitating the smooth flow of the electrolyte into the electrode body 100.
[0039] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.
[0040] [Aspect 1] An electrode body comprising a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet and the negative electrode sheet are wound around the separator, and the electrode body is composed of a wound body. A current collector plate connected to the electrode body, A cell case housing the electrode body and the current collector plate, The cell case contains an electrolyte solution, Each of the positive electrode sheet and the negative electrode sheet is, Current collector foil and The current collector foil has an active material layer provided on its surface, The aforementioned current collector foil is The active material layer is provided, and the electrode bodies have main regions arranged to overlap each other in the radial direction, The electrode body has an end region formed outside the main region in the axial direction, where the active material layer is not provided, The active material layer includes a layer end formed at the end in the axial direction, The end regions are separated from each other in the circumferential direction of the electrode body and have a plurality of tabs bent relative to the main region. The plurality of tabs are arranged such that a covering region is formed that covers a portion of the layer end, and an exposed region is formed that exposes the rest of the layer end. The current collector plate is connected to the covered area, which is a storage cell.
[0041] In this energy storage cell, the connection between the current collector foil and the current collector plate is ensured in the covered area, and the electrolyte that leaks out from the electrode body during high-rate charging and discharging is re-impregnated into the electrode body through the exposed area, thereby suppressing electrolyte shortage in the electrode body.
[0042] [Aspect 2] The energy storage cell according to embodiment 1, wherein the exposed region includes an annular exposed region that is connected in a ring in the circumferential direction.
[0043] [Aspect 3] The energy storage cell according to embodiment 2, wherein the annular exposed region is formed inside the covering region in the radial direction.
[0044] In this embodiment, impregnation of the electrolyte from the inside to the outside in the radial direction is promoted.
[0045] [Aspect 4] The energy storage cell according to embodiment 1, wherein the covering region includes an annular covering region connected in a ring shape in the circumferential direction.
[0046] In this embodiment, the outflow of electrolyte from the electrode body during high-rate charging and discharging is effectively blocked by the annular coating region, and the electrolyte that has leaked out of the electrode body is re-impregnated into the electrode body through the exposed region. Therefore, the shortage of electrolyte in the electrode body is more reliably suppressed.
[0047] [Aspect 5] The energy storage cell according to embodiment 4, wherein the annular covering region is formed inside the exposed region in the radial direction.
[0048] In this embodiment, a relatively large area of the exposed region is secured, which allows the electrolyte to flow smoothly into the electrode body through the exposed region.
[0049] [Aspect 6] The energy storage cell according to embodiment 4, wherein the annular covering region is formed outside the exposed region in the radial direction.
[0050] In this embodiment, an exposed region is formed on the winding core side of the electrode body, where stress concentration and heat buildup are likely to occur, thus facilitating the smooth flow of the electrolyte into the electrode body.
[0051] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]
[0052] 1 Energy storage cell, 100 Electrode body, 110 Positive electrode sheet, 112 Positive current collector foil, 112a Main region, 112b End region, 112b1 Tab, 114 Positive active material layer, 114a Layer end, 120 Negative electrode sheet, 122 Negative current collector foil, 122a Main region, 122b End region, 124 Negative active material layer, 124a Layer end, 130 Separator, 200 Cell case, 210 Case body, 220 Top wall, 230 Bottom wall, 300 External terminal, 410 Positive current collector plate, 420 Negative current collector plate, 510 Insulating material, R10 Covered region, R12 Annular covered region, R20 Exposed region, R22 Annular exposed region.
Claims
1. An electrode body comprising a positive electrode sheet and a negative electrode sheet wound around each other with a separator in between, A negative electrode current collector plate connected to the electrode body, A cell case housing the electrode body and the negative electrode current collector plate, The cell case contains an electrolyte solution, The aforementioned cell case has a bottom wall, The bottom wall is in contact with the negative electrode current collector plate. Each of the positive electrode sheet and the negative electrode sheet is, Current collector foil and The current collector foil has an active material layer provided on its surface, The aforementioned current collector foil is The main region where the active material layer is provided, It has an end region where the active material layer is not provided, The active material layer includes a layer end formed at the end of the electrode body in the axial direction, The end region has a plurality of tabs that are folded relative to the main region, The plurality of tabs are arranged such that a covering region is formed that covers a portion of the layer end, and an exposed region is formed that exposes the rest of the layer end. The negative electrode current collector plate is connected to the covered area, The aforementioned covering region includes an annular covering region that is connected in a ring shape in the circumferential direction to the electrode body, thereby forming an energy storage cell.
2. The energy storage cell according to claim 1, wherein the exposed region includes an annular exposed region that is connected in an annular direction in the circumferential direction of the electrode body.
3. The energy storage cell according to claim 2, wherein the annular exposed region is formed inside the covering region in the radial direction of the electrode body.
4. The energy storage cell according to claim 1, wherein the annular covering region is formed inside the exposed region in the radial direction of the electrode body.
5. The energy storage cell according to claim 1, wherein the annular covering region is formed outside the exposed region in the radial direction of the electrode body.