Stress fatigue resistant core structure
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2026-08-14
AI Technical Summary
另外由于正极片和负极片分别连接有极耳，极耳的另一端与电池盖板进行连接，因此在电池卷芯结构充放电时，扩张和收缩的状态会导致应力拉扯极耳，此时极耳被电池盖板等固定，因此极片与极耳的连接处造成断裂的现象，出现电池供电失效的问题，为了解决此类问题，现提出一种耐应力疲劳的卷芯结构
[0013]本实用新型的有益效果是，本实用新型采用将正极耳和负极耳均设于卷芯的起始段，使电池在充放电时，减少卷芯扩张与收缩的应力叠加对正极耳和负极耳的应力拉扯，从而降低正极片和负极片断裂的风险，提高电池的使用寿命。
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Figure CN224637231U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of lithium-ion battery technology, specifically relating to a core structure resistant to stress fatigue. Background Technology
[0002] Currently, the mainstream lithium-ion battery core structure on the market is the wound structure, which includes positive electrode sheets, negative electrode sheets, and a separator layer used to separate the positive and negative electrode sheets. This structure has advantages such as structural stability, high space utilization, and high production efficiency. However, during the charging and discharging process of lithium-ion batteries, the thickness of the positive and negative electrode sheets will change slightly due to the insertion and extraction of lithium ions. As the number of radially stacked electrode sheets increases, the slight deformation of the core also increases, leading to an increase in radial stress accumulation. Specifically, since the central hole area of the core is in a relaxed state without fixation, the stress here can be greatly released inward. However, the outer periphery of the core has the largest number of electrode layers accumulated, and the outer periphery is generally bound and fixed by the outer tape and shell of the core, preventing stress release. The maximum stress accumulation is reached at the outermost periphery of the core. The outer periphery of the core is the area of greatest stress deformation, causing the circumferential tensile force of the electrode sheets in this area to reach its maximum value. In addition, since the positive and negative electrodes are connected to tabs respectively, and the other end of the tabs is connected to the battery cover, the expansion and contraction during the charging and discharging of the battery core structure will cause stress to pull the tabs. At this time, the tabs are fixed by the battery cover, etc., so the connection between the electrode and the tab will break, resulting in battery power supply failure. In order to solve this problem, a stress fatigue resistant core structure is proposed. Utility Model Content
[0003] This utility model aims to solve at least one of the technical problems existing in the prior art.
[0004] Therefore, this utility model proposes a stress fatigue resistant core structure, which has the advantages of reducing stress on the tabs and improving battery life.
[0005] According to an embodiment of the present invention, a stress fatigue resistant core structure includes: a positive electrode sheet and a negative electrode sheet; the positive electrode sheet is connected to a positive electrode tab, which is located at the beginning of the length direction of the positive electrode sheet; the negative electrode sheet is connected to a negative electrode tab, which is located at the beginning of the length direction of the negative electrode sheet; the positive electrode sheet and the negative electrode sheet are stacked and wound to form a core, and a separator layer is provided between the positive electrode sheet and the negative electrode sheet.
[0006] According to one embodiment of the present invention, both the positive electrode tab and the negative electrode tab have at least one inner groove formed along the width direction.
[0007] According to one embodiment of the present invention, the inner groove is located in the middle section of the positive or negative tab and corresponds to the edge of the positive or negative electrode sheet to which it is connected.
[0008] According to one embodiment of the present invention, the number of inner grooves is two, and the two inner grooves are arranged at intervals.
[0009] According to one embodiment of the present invention, the two inner grooves are located on both sides of the width of their corresponding positive or negative tabs.
[0010] According to one embodiment of the present invention, the protruding ends of the positive electrode tab and the negative electrode tab are respectively located at both ends of the winding core.
[0011] According to one embodiment of the present invention, the positive electrode tab and the negative electrode tab are both located at the same end of the winding core.
[0012] According to one embodiment of the present invention, the inner groove is rectangular, inverted V-shaped, semi-circular, or inverted U-shaped.
[0013] The beneficial effect of this utility model is that by placing both the positive and negative tabs at the beginning of the winding core, the stress of the winding core expanding and contracting during charging and discharging is reduced, thereby reducing the stress pulling on the positive and negative tabs, thus reducing the risk of breakage of the positive and negative electrode sheets and improving the service life of the battery.
[0014] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.
[0015] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the following description of the embodiments with accompanying drawings, in which:
[0017] Figure 1 This is a schematic diagram of the positive and negative electrode sheets before winding.
[0018] Figure 2 This is a schematic diagram showing the positions of the positive and negative electrode tabs after the positive and negative electrode sheets of this utility model are wound together;
[0019] Figure 3 This is a schematic diagram of the semi-circular structure of the inner groove of this utility model;
[0020] Figure 4 This is a schematic diagram of the inverted V-shaped structure of the inner groove of this utility model;
[0021] Figure 5 This is a schematic diagram of the rectangular structure of the inner groove of this utility model;
[0022] Figure 6 This is a schematic diagram of the inverted U-shaped structure of the inner groove of this utility model;
[0023] Figure label:
[0024] 1. Positive electrode plate; 2. Negative electrode plate; 31. Positive electrode tab; 32. Negative electrode tab; 4. Inner groove. Detailed Implementation
[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0026] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0028] The stress fatigue resistant core structure of this utility model is described in detail below with reference to the accompanying drawings.
[0029] like Figures 1-6As shown, the stress fatigue resistant core structure according to an embodiment of the present invention includes: a positive electrode sheet 1 and a negative electrode sheet 2; the positive electrode sheet 1 is connected to a positive electrode tab 31, which is located at the beginning of the length direction of the positive electrode sheet 1; the negative electrode sheet 2 is connected to a negative electrode tab 32, which is located at the beginning of the length direction of the negative electrode sheet 2; the positive electrode sheet 1 and the negative electrode sheet 2 are stacked and wound to form a core, and a separator layer is provided between the positive electrode sheet 1 and the negative electrode sheet 2.
[0030] In this embodiment, the positive electrode tab 31 is welded to the positive electrode sheet 1, and then the negative electrode tab 32 is welded to the negative electrode sheet 2. Alternatively, the positive electrode tab 31 and the negative electrode tab 32 are left out during the preparation of the positive electrode sheet 1 and the negative electrode sheet 2, so that the positive electrode tab 31 and the positive electrode sheet 1 are integrally formed, and the negative electrode tab 32 and the negative electrode sheet 2 are integrally formed. Then, a separator layer is added between the positive electrode sheet 1 and the negative electrode sheet 2. Finally, the positive electrode sheet 1, the separator layer, and the negative electrode sheet 2 are wound to form a core. During assembly, the core is placed inside the battery casing, and the positive and negative electrode connection structures of the battery are connected by the positive electrode tab 31 and the negative electrode tab 32. During winding, winding begins from the starting section of the positive electrode sheet 1 and the negative electrode sheet 2. The starting section is the area near the center of the core. For example, if the formed core has 10 layers, and the layers are 1-10 from the inside out, then the starting section is layers 1-4 of the core. The positive electrode tab 31 and the negative electrode tab 32 can be placed in any layer from layers 1-4. Preferably located in the first layer of the core, by placing the positive tab 31 and the negative tab 32 near the central hole area of the core, the stress tension here is not affected by stress accumulation. Therefore, during battery charging and discharging, the tension on the positive tab 31 and the negative tab 32 caused by battery expansion and contraction is reduced, thereby reducing the risk of breakage of the positive electrode 1 and the negative electrode 2 and improving the battery's service life.
[0031] The positive electrode tab 31 and the negative electrode tab 32 can also be set in different layers of the winding core to avoid contact between the positive electrode tab 31 and the negative electrode tab 32; in addition, to avoid the positive electrode tab 31 and the negative electrode tab 32 being too wide and difficult to wind, the positive electrode tab 31 and the negative electrode tab 32 can be set in the 2nd to 4th layers of the winding core to reduce the manufacturing difficulty.
[0032] Both the positive electrode tab 31 and the negative electrode tab 32 have at least one inner groove 4 formed along the width direction.
[0033] In this embodiment, in a small button cell battery, due to the small size of the core, the welding area of the positive tab 31 and negative tab 32 needs to have a certain width to ensure the welding area is sufficient for welding the positive tab 31 and negative tab 32 to the positive electrode sheet 1, the negative electrode sheet 2, and the battery cover. However, the wider positive tab 31 and negative tab 32 are affected by the core diameter, and after the core is formed, the wider positive tab 31 and negative tab 32 also have a certain bending curvature. Therefore, when bending is required after connecting with the battery cover, interference occurs. To address this, an inner groove 4 is formed on the positive tab 31 and negative tab 32, which narrows the width of the bending position, thereby avoiding interference with bending and making bending easier.
[0034] The groove 4 is located in the middle section of the positive electrode tab 31 or the negative electrode tab 32, and corresponds to the edge of the positive electrode plate 1 or the negative electrode plate 2 connected to it.
[0035] In other words, after one end of the positive electrode tab 31 or negative electrode tab 32 is overlapped with the positive electrode sheet 1 or negative electrode sheet 2 by welding or other means, the other end of the positive electrode tab 31 or negative electrode tab 32 protrudes from the edge of the positive electrode sheet 1 or negative electrode sheet 2 in the width direction. The inner groove 4 is set at the opposite position of this edge, which is conducive to the bent part of the positive electrode tab 31 or negative electrode tab 32 being closer to the end face of the core, so as to save the space occupied in the battery casing.
[0036] There are two inner grooves 4, which are spaced apart.
[0037] In this embodiment, when there is one inner groove 4, it can be located in the middle region of the width direction of the positive electrode 31 or the negative electrode 32. That is, at this time, the two ends of the positive electrode 31 or the negative electrode 32 are connected by two thin strips to avoid interference with bending. Alternatively, the inner groove 4 can be located on one side of the positive electrode 31 or the negative electrode 32, so that the two ends of the positive electrode 31 or the negative electrode 32 are connected by one thin strip. When there are two inner grooves 4, three thin strips can be formed to connect the two ends of the positive electrode 31 or the negative electrode 32, or two thin strips can be formed to connect the two ends of the positive electrode 31 or the negative electrode 32, or one thin strip can be formed to connect the two ends of the positive electrode 31 or the negative electrode 32.
[0038] The two inner grooves 4 are located on both sides of the width of their corresponding positive electrode tab 31 or negative electrode tab 32. At this time, the two inner grooves 4 form a thin strip connecting the two ends of the positive electrode tab 31 or negative electrode tab 32.
[0039] The protruding ends of the positive electrode tab 31 and the negative electrode tab 32 are located at both ends of the winding core, respectively.
[0040] In other words, the positive tab 31 and the negative tab 32 are connected to the positive and negative terminals at both ends of the battery casing, respectively, to accommodate smaller batteries and avoid the phenomenon of overlapping arrangement of the positive tab 31 and the negative tab 32.
[0041] Both the positive tab 31 and the negative tab 32 are located at the same end of the winding core.
[0042] This design is suitable for batteries where the positive tab 31 and negative tab 32 can be evenly distributed, allowing the positive tab 31 and negative tab 32 to be welded only at one end of the battery casing. This avoids the positive tab 31 and negative tab 32 occupying space at both ends of the battery, thus saving internal space in the battery.
[0043] The inner groove 4 is rectangular, inverted V-shaped, semi-circular, or inverted U-shaped.
[0044] Preferably, the inner groove 4 is semi-circular or inverted U-shaped to form a smooth connecting surface and reduce the phenomenon of tearing from the included angle of the inner groove 4.
[0045] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0046] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A stress fatigue resistant core construction characterized by, include: Positive electrode plate (1), the positive electrode plate (1) is connected to a positive electrode tab (31), the positive electrode tab (31) is located at the beginning of the length direction of the positive electrode plate (1); A negative electrode plate (2) is connected to a negative electrode tab (32), which is located at the beginning of the length direction of the negative electrode plate (2). The positive electrode (1) and the negative electrode (2) are stacked and wound to form a core, and a separator layer is provided between the positive electrode (1) and the negative electrode (2).
2. The stress fatigue resistant core structure of claim 1, wherein, Both the positive electrode tab (31) and the negative electrode tab (32) have at least one inner groove (4) formed along the width direction.
3. The stress fatigue resistant core structure of claim 2, wherein, The groove (4) is located in the middle section of the positive electrode tab (31) or the negative electrode tab (32), and corresponds to the edge of the positive electrode plate (1) or the negative electrode plate (2) to which it is connected.
4. The stress fatigue resistant core structure of claim 3, wherein, The number of the inner grooves (4) is two, and the two inner grooves (4) are spaced apart.
5. The stress fatigue resistant core structure of claim 4, wherein, The two inner grooves (4) are located on both sides of the width of their corresponding positive tab (31) or negative tab (32).
6. The stress fatigue resistant core structure of claim 5, wherein, The protruding ends of the positive electrode tab (31) and the negative electrode tab (32) are located at both ends of the core, respectively.
7. The stress fatigue resistant core structure of claim 5, wherein, The positive tab (31) and the negative tab (32) are both located at the same end of the core.
8. The stress fatigue resistant core structure of claim 2, wherein, The inner groove (4) is rectangular, inverted V-shaped, semi-circular, or inverted U-shaped.