Battery cell and battery
By applying a coating to the corner section of the first electrode of the battery cell to create a height difference for storing electrolyte, the problem of lithium plating caused by electrolyte loss during charge-discharge cycles in lithium-ion batteries is solved, thus improving the stability and performance of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG LIWINON ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-03-24
- Publication Date
- 2026-05-15
AI Technical Summary
During the charge-discharge cycle of a lithium-ion battery, the mechanical stress concentration caused by volume expansion and contraction in the corner area of the cell leads to electrolyte loss and subsequently lithium plating.
A coating is applied to the corner section of the first electrode of the battery cell to create a height difference for storing electrolyte, improving the uniform distribution of electrolyte, and enhancing the bonding strength through conductive adhesive layer, conductive ceramic layer or conductive metal layer to prevent detachment and form a stable electrolyte flow path in the battery cell.
It effectively improves the problem of electrolyte deficiency at the corners of the battery cell, reduces lithium plating, and enhances the stability and performance of the battery.
Smart Images
Figure CN224248762U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery manufacturing technology, specifically to a battery cell and a battery. Background Technology
[0002] During the use of lithium-ion batteries, the cells undergo repeated volume expansion and contraction due to charge-discharge cycles. This expansion leads to uneven distribution of mechanical stress inside the cell, and stress concentration easily occurs in corner areas due to geometric constraints. When the electrolyte gradually leaks out at the corners of the cell under pressure, the lithium-ion transport path in that area is blocked, the lithium-ion concentration gradient on the negative electrode surface becomes unbalanced, and lithium plating is easily caused. Utility Model Content
[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell that can improve the lithium plating phenomenon at corners.
[0004] This utility model also proposes a battery having the above-mentioned battery cell.
[0005] According to a first aspect embodiment of the present invention, a battery cell is formed by stacking and winding a first electrode and a second electrode. The first electrode includes a plurality of first straight segments and a plurality of first corner segments connected sequentially along the winding direction of the battery cell. Each first corner segment has two first straight segments connected to its two ends. The first straight segment includes a first current collector and a first active material layer. Two first active material layers are respectively provided on both sides of the first current collector. The first corner segment includes a first part. The first part includes a first coating, the first current collector, and the first active material layer. The first coating is disposed between the first current collector and the first active material layer. The thickness of the first straight segment is less than the thickness of the first part.
[0006] The battery cell according to the present invention has at least the following beneficial effects: The battery cell of the present invention has a first part provided on the first corner segment in the first electrode plate, and a first coating is provided in the first part. After coating and rolling, the first active material layer forms a height difference due to the presence of the first coating. The presence of the height difference in the battery cell is beneficial for storing electrolyte, thereby improving the lithium plating caused by the lack of electrolyte at the expansion corner of the long-cycle battery cell.
[0007] According to some embodiments of the present invention, the first coating is any one of a conductive adhesive layer, a conductive ceramic layer, and a conductive metal layer.
[0008] According to some embodiments of the present invention, the first electrode is a positive electrode.
[0009] According to some embodiments of the present invention, the first part includes two first coatings, and two first coatings are respectively provided on both sides of the first current collector.
[0010] According to some embodiments of the present invention, the first corner segment includes a second part, the second part is connected to the first part, the second part includes the first current collector and the first active material, two layers of the first active material are respectively provided on both sides of the first current collector, and the thickness of the first straight segment is equal to the thickness of the second part.
[0011] According to some embodiments of the present invention, both the first part and the second part are multiple, and multiple first parts and multiple second parts are alternately arranged along the width direction of the first electrode.
[0012] According to some embodiments of the present invention, along the width direction of the battery cell, the first portions of two adjacent first corner segments are staggered.
[0013] According to some embodiments of the present invention, the thickness of the first straight section is H1, the thickness of the first coating is H2, the width of the first electrode is D1, the width of the first coating is D2, (H1*0.5%)≤H2≤(H1*42.5%), and / or, (D1*0.5%)≤D2≤(D1*90%).
[0014] According to some embodiments of the present invention, the second electrode includes a plurality of second straight sections and a plurality of second corner sections connected sequentially along the winding direction of the battery cell. Each second corner section is connected to two second straight sections at both ends. The second straight section includes a second current collector and a second active material layer. Two second active material layers are respectively provided on both sides of the second current collector. The second corner section includes a third part, which includes a second coating, the second current collector, and the second active material layer. The second coating is disposed between the second current collector and the second active material layer. The thickness of the second straight section is less than the thickness of the third part.
[0015] The battery according to the second aspect embodiment of the present invention includes the battery cell described in any one of the first aspect embodiments.
[0016] The battery according to the present invention has at least the following beneficial effects: The battery cell of the present invention has a first part provided on the first corner section in the first electrode plate, and a first coating is provided in the first part. After coating and rolling, the first active material layer forms a height difference due to the presence of the first coating. The presence of the height difference in the battery cell is beneficial for storing electrolyte, thereby improving the lithium plating caused by the lack of electrolyte at the expansion corner of the long-cycle battery cell, thereby improving the battery cell quality.
[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:
[0019] Figure 1 This is an overall schematic diagram of the battery cell in one embodiment of the present invention;
[0020] Figure 2 for Figure 1 Enlarged view of region A in the middle;
[0021] Figure 3 This is a partial cross-sectional view of a first embodiment of the first electrode sheet in one embodiment of the present invention;
[0022] Figure 4 This is a partial cross-sectional view of a second embodiment of the first electrode sheet in one embodiment of the present invention;
[0023] Figure 5 This is a plan view of the first embodiment of the first electrode sheet in one embodiment of the present utility model;
[0024] Figure 6 This is a schematic diagram of the second embodiment of the first electrode sheet in one embodiment of the present invention;
[0025] Figure 7 This is a schematic diagram of the third embodiment of the first electrode sheet in one embodiment of the present invention.
[0026] Reference numerals: Cell 100, First electrode 101, Second electrode 102, First straight section 103, First corner section 104, Second straight section 105, Second corner section 106, Separator 107, First part 201, Second part 202, Third part 203, First current collector 301, First active material layer 302, First coating layer 303, Undercoating layer 304, Tab 501. Detailed Implementation
[0027] 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.
[0028] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this utility model.
[0029] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0031] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. 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.
[0032] refer to Figures 1 to 4According to a first aspect embodiment of the present invention, the battery cell 100 is formed by stacking and winding a first electrode 101 and a second electrode 102. The first electrode 101 includes a plurality of first straight segments 103 and a plurality of first corner segments 104 connected sequentially along the winding direction of the battery cell 100. Each first corner segment 104 is connected to two first straight segments 103 at both ends. The first straight segment 103 includes a first current collector 301 and a first active material layer 302. Two first active material layers 302 are respectively provided on both sides of the first current collector 301. The first corner segment 104 includes a first part 201. The first part 201 includes a first coating 303, a first current collector 301 and a first active material layer 302. The first coating 303 is disposed between the first current collector 301 and the first active material layer 302. The thickness of the first straight segment 103 is less than the thickness of the first part 201. The battery cell 100 of this embodiment features a first portion 201 formed on a first corner segment 104 within the first electrode 101. A first coating 303 is disposed within the first portion 201. After coating and rolling, the first active material layer 302 forms a height difference due to the presence of the first coating 303. This height difference in the battery cell 100 facilitates electrolyte storage, thereby mitigating lithium plating caused by electrolyte loss at the expansion corner of the long-cycle battery cell 100. It should be noted that, referring to… Figure 1 A diaphragm 107 is also provided between the first electrode 101 and the second electrode 102. The diaphragm 107 is used to isolate the first electrode 101 and the second electrode 102 to prevent short circuits and improve safety. (Reference) Figure 3 In some embodiments of this utility model, a base coating 304 is further provided within the first electrode 101. The base coating 304 can be disposed between the first current collector 301 and the first active material layer 302, or between the first current collector 301 and the first coating layer 303. Similarly, the first coating layer 303 can also be disposed between the current collector 301 and the base coating 304. The base coating 304 is mainly used to enhance the adhesion between the first current collector 301 and the first active material layer 302 and the first coating layer 303, preventing them from falling off. (Reference) Figure 5 The first electrode 101 is also provided with a tab 501, which is used to connect the battery cell 100 to the external circuit. Furthermore, the second electrode 102 is also provided with a tab 501 and a base coating 304.
[0033] In some embodiments of this utility model, the first coating 303 is any one of a conductive adhesive layer, a conductive ceramic layer, and a conductive metal layer. The electrode material itself is relatively brittle, making it prone to breakage when subjected to bending or stretching forces, especially at corners where the electrode needs to change direction, resulting in more concentrated stress. Furthermore, the electrode expands during cyclic use, making breakage more likely. The conductive adhesive layer needs sufficient bonding strength to ensure it adheres firmly to the current collector or active material, preventing detachment or delamination during use. Therefore, the viscous conductive adhesive layer can also restrain the expansion of the first electrode 101, improving the breakage phenomenon. In addition, even if breakage or partial breakage occurs, the conductive adhesive layer can, to some extent, compensate for the electron conduction of the first current collector 301. Similarly, the conductive ceramic layer or the conductive metal layer can also, to some extent, compensate for the electron conduction of the first current collector 301 when breakage or partial breakage occurs. It should be noted that in some embodiments of this utility model, the second coating on the second electrode 102 can also be set as any one of a conductive adhesive layer, a conductive ceramic layer, and a conductive metal layer. Furthermore, Figures 3 to 7 The arrangement of the first part 201 and the structural arrangement of the first coating 303, as well as the ratio range of thickness and width shown, are also applicable to the second corner segment 106 of the second electrode 102.
[0034] In some embodiments of this utility model, the first electrode 101 is a positive electrode. The positive electrode is a key component in a lithium battery, mainly responsible for energy release and reception. Specifically, the active material in the positive electrode can chemically react with the active material of the negative electrode, thereby releasing electrons, which is the basis for the battery to generate current. At the same time, during charging, the positive electrode can also receive electrons provided by an external power source, increasing the lithium ion potential in the positive electrode material, thereby storing energy. During the charging process of the lithium battery, lithium ions in the positive electrode will be extracted from the crystal structure of the positive electrode material and enter the electrolyte. However, the conductivity of the conductive adhesive layer is weaker than that of the first current collector 301. Therefore, when the first coating 303 is a conductive adhesive layer, the internal resistance of the region where the first part 201 of the first corner segment 104 is located is larger than that of other parts, which slows down the extraction rate of lithium ions, allowing the anode to have more time to embed, thereby further improving the lithium plating phenomenon at the corner of the cell 100.
[0035] refer to Figure 2 and Figure 4In some embodiments of this invention, the first part 201 includes two first coatings 303, with two first coatings 303 respectively provided on both sides of the first current collector 301. When the double-sided layer is provided, the electrolyte can penetrate more evenly from both sides of the first electrode 101 into the first active material layer 302. This even supply helps ensure the reaction consistency of the entire active material layer, avoiding local over- or under-reaction caused by uneven electrolyte distribution, thereby further improving the stability of battery performance. Furthermore, the double-sided layer can provide a larger electrolyte storage space.
[0036] It should be noted that the reference Figures 2 to 4 In some embodiments of this utility model, the first coating 303 can be disposed on one side of the first electrode 101, or symmetrically disposed on both sides of the first electrode 101, or asymmetrically disposed on both sides of the first electrode 101, i.e., staggered from each other.
[0037] refer to Figure 3 , Figures 5 to 7 In some embodiments of this utility model, the first corner segment 104 includes a second part 202 connected to the first part 201. The second part 202 includes a first current collector 301 and a first active material. Two first active material layers 302 are respectively provided on both sides of the first current collector 301. The thickness of the first straight segment 103 is equal to the thickness of the second part 202. This arrangement allows the convex shape of the first part 201 and the relatively lower second part 202 to cooperate and jointly form the corner segment of the first electrode 101. This synergistic effect can make the shape of the corner segment exhibit a more pronounced undulating state. When the shape of the corner segment changes in this way, the electrolyte storage capacity of the corner segment is improved, thereby effectively improving the lithium plating phenomenon at the corner of the battery cell 100.
[0038] refer to Figures 5 to 7 In some embodiments of this utility model, there are multiple first parts 201 and multiple second parts 202, which are alternately arranged along the width direction of the first electrode 101. The alternating arrangement of multiple first parts 201 and multiple second parts 202 can further enhance the undulation of the corner section shape, thereby further enhancing the electrolyte storage capacity in the corner section.
[0039] It should be noted that the reference Figures 5 to 7 In some embodiments of this utility model, multiple first parts 201 and second parts 202 can also be arranged along the length direction of the first electrode 101, so that the first electrode 101 can be wound up as follows: Figure 2As shown, multiple first portions 201 are formed in the width direction of the cell 100 to improve the electrolyte storage effect. Specifically, along the length direction of the first electrode 101, adjacent first portions can be as follows: Figure 5 and Figure 6 The flush setting shown can also be as follows: Figure 7 The interleaved arrangement shown can be used in terms of frequency distribution as follows. Figure 5 The intervals shown are set at some corner sections, or as follows: Figure 6 The continuous arrangement shown is present at each corner segment. Furthermore, the first part 201 and the second part 202 can also be stacked along the length of the first electrode 101 at both ends of the central axis of the corner segment (not shown in the figure), with various arrangement methods that can be adjusted and selected according to actual needs. Further, Figures 5 to 7 The arrangement of the first part 201 can be applied to different positions within a battery cell 100. For example, the first part 201 can be arranged more densely inside the battery cell 100, or more sparsely near the outer ring of the battery cell 100.
[0040] refer to Figure 2 In some embodiments of this invention, the first portions 201 of two adjacent first corner segments 104 are staggered along the width direction of the battery cell 100. This design causes the protruding structure formed inside the battery cell 100 to exhibit a gradient distribution in three-dimensional space. By eliminating local abrupt thickness regions, i.e., by staggering the first portions 201, local stress concentration or active material layer peeling caused by excessive thickness at a certain point in the width direction of the battery cell 100 can be effectively avoided, thereby maintaining structural stability and meeting the energy density requirements.
[0041] refer to Figure 2 and Figure 5 In some embodiments of this utility model, the thickness of the first straight section 103 is H1, the thickness of the first coating 303 is H2, the width of the first electrode 101 is D1, the width of the first coating 303 is D2, (H1*0.5%) ≤ H2 ≤ (H1*42.5%), and / or, (D1*0.5%) ≤ D2 ≤ (D1*90%). It should be noted that... Figure 3 The thickness marked is the thickness of the second part 202, but as mentioned above, the thickness of the second part 202 is actually the same as the thickness of the first straight section 103. This marking is to more conveniently show the dimensional relationship between H1 and H2.
[0042] The thickness H2 of the first coating 303 can specifically be H1*0.5%, H1*20%, H1*42.5%, etc. When the thickness ratio of the first coating 303 to the first electrode 101 is appropriate, it can promote a more uniform distribution of electrolyte in the first active material layer 302. The appropriate ratio allows the height difference of the first active material layer 302 to guide the electrolyte to form a stable flow path in the height difference region, ensuring that the electrolyte can fully wet all parts of the first active material layer 302 and reduce the situation of local electrolyte drying or enrichment. When H2 is less than H1*0.5%, it is not possible to effectively generate a sufficient height difference in the first active material layer 302 to achieve the expected optimization effect. In addition, in the manufacturing process, it is difficult to precisely control the first coating 303 if it is too thin. When H2 is greater than H1*42.5%, the first coating 303 is too thick, which may reduce the effective utilization area of the first active material layer 302, and the excessively thick layer will increase the internal resistance of the cell 100.
[0043] The width D2 of the first coating 303 can specifically be D1*0.5%, D1*20%, D1*50%, D1*90%, etc. When the ratio of the width of the first coating 303 to the width of the first electrode 101 is appropriate, a transverse flow channel can be formed in the active material layer. This structure can guide the electrolyte to diffuse uniformly along the width direction, avoiding uneven wetting caused by local electrolyte retention or shortage, especially improving the reaction efficiency of the edge area of the cell 100. When D2 is greater than D1*90%, the width of the first coating 303 is too wide. The excessively wide layer will squeeze the transverse space of the active material layer, resulting in a reduction of effective active material per unit area, directly reducing the areal capacity of the cell 100. When D2 is less than D1*0.5%, the first coating 303 is too narrow and cannot form an effective transverse flow channel. The electrolyte still mainly penetrates longitudinally, resulting in limited improvement in the wetting efficiency in the width direction, making it difficult to solve the problem of insufficient electrolyte supply in the edge area.
[0044] refer to Figure 2In some embodiments of this utility model, the second electrode 102 includes a plurality of second straight segments 105 and a plurality of second corner segments 106 connected sequentially along the winding direction of the battery cell 100. Each second corner segment 106 has two second straight segments 105 connected to its two ends. Each second straight segment 105 includes a second current collector and a second active material layer. Two second active material layers are respectively provided on both sides of the second current collector. The second corner segment 106 includes a third part 203, which includes a second coating, a second current collector, and a second active material layer. The second coating is disposed between the second current collector and the second active material layer. The thickness of the second straight segment 105 is less than the thickness of the third part 203. The second electrode 102 also features a height-enhancing structure, allowing a height difference in the second active material layer at the corner of the second electrode 102, further improving the electrolyte storage capacity. It should be noted that the structures of the first electrode 101 and the first coating 303 described above are also applicable to the second coating.
[0045] The battery according to a second aspect embodiment of the present invention includes a cell 100 as described in any of the first aspect embodiments. The cell 100 of this embodiment features a first portion 201 formed on a first corner segment 104 within a first electrode 101. A first coating 303 is provided within the first portion 201. After coating and rolling, the first active material layer 302 forms a height difference due to the presence of the first coating 303. This height difference in the cell 100 facilitates electrolyte storage, thereby mitigating lithium plating at the corner caused by expansion of the cell 100 during long-cycle operation, thus improving the battery quality using the cell 100.
[0046] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.
Claims
1. A battery cell, characterized in that, The first electrode is formed by stacking and winding a first electrode and a second electrode. The first electrode includes a plurality of first straight segments and a plurality of first corner segments connected sequentially along the winding direction of the cell. Each first corner segment is connected to two first straight segments at both ends. The first straight segment includes a first current collector and a first active material layer. Two first active material layers are respectively provided on both sides of the first current collector. The first corner segment includes a first part. The first part includes a first coating, the first current collector and the first active material layer. The first coating is disposed between the first current collector and the first active material layer. The thickness of the first straight segment is less than the thickness of the first part.
2. The battery cell according to claim 1, characterized in that, The first coating is any one of a conductive adhesive layer, a conductive ceramic layer, and a conductive metal layer.
3. The battery cell according to claim 2, characterized in that, The first electrode is a positive electrode.
4. The battery cell according to claim 1, characterized in that, The first part includes two first coatings, and two first coatings are respectively provided on both sides of the first current collector.
5. The battery cell according to claim 1, characterized in that, The first corner segment includes a second part, which is connected to the first part. The second part includes the first current collector and the first active material. Two layers of the first active material are provided on both sides of the first current collector. The thickness of the first straight segment is equal to the thickness of the second part.
6. The battery cell according to claim 5, characterized in that, Both the first part and the second part are multiple, and multiple first parts and multiple second parts are alternately arranged along the width direction of the first electrode.
7. The battery cell according to claim 6, characterized in that, Along the width direction of the battery cell, the first portions of two adjacent first corner segments are staggered.
8. The battery cell according to claim 2, characterized in that, The thickness of the first straight section is H1, the thickness of the first coating is H2, the width of the first electrode is D1, the width of the first coating is D2, (H1*0.5%)≤H2≤(H1*42.5%), and / or, (D1*0.5%)≤D2≤(D1*90%).
9. The battery cell according to claim 1, characterized in that, The second electrode includes a plurality of second straight sections and a plurality of second corner sections connected sequentially along the winding direction of the battery cell. Each second corner section is connected to two second straight sections at both ends. The second straight section includes a second current collector and a second active material layer. Two second active material layers are respectively provided on both sides of the second current collector. The second corner section includes a third part, which includes a second coating, the second current collector, and the second active material layer. The second coating is disposed between the second current collector and the second active material layer. The thickness of the second straight section is less than the thickness of the third part.
10. A battery, characterized in that, Includes the battery cell as described in any one of claims 1-9.