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JP-2026514430-A - Rechargeable batteries and electronic devices

JP2026514430AJP 2026514430 AJP2026514430 AJP 2026514430AJP-2026514430-A

Abstract

This application provides a secondary battery and electronic equipment, the secondary battery comprising an electrode assembly, the electrode assembly comprising a positive electrode plate, a negative electrode plate and a separator, the separator provided between the positive electrode plate and the negative electrode plate, the negative electrode plate comprising a negative electrode current collector and a negative electrode active material layer, a groove formed on the surface of the negative electrode active material layer facing the positive electrode plate, the width of the groove being W mm and the pitch being S mm, the thickness of the electrode assembly being T 1 mm, and satisfying W ≥ S × T 1/1000 . This application allows for adjusting the contact area between the surface of the negative electrode plate and the separator according to lithium-ion batteries of different thicknesses by adjusting the relationship between the width of the groove, the pitch of the groove and the thickness of the electrode assembly within the scope of this application, thereby increasing the adhesion between the negative electrode plate and the separator, improving the stability of the negative electrode plate, improving the deformation problem of the lithium-ion battery, and improving the cycle stability and safety of the lithium-ion battery. [Selection Diagram] Figure 2

Inventors

  • 孔 森

Assignees

  • 寧徳新能源科技有限公司

Dates

Publication Date
20260511
Application Date
20230330

Claims (15)

  1. Equipped with an electrode assembly, The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The separator is provided between the positive electrode plate and the negative electrode plate. The aforementioned negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. A groove is formed on the surface of the negative electrode active material layer facing the positive electrode plate, the width of the groove is W mm, and the pitch of the groove is S mm. A secondary battery characterized in that the thickness of the electrode assembly is T 1 mm and W ≥ S × T 1 / 1000.
  2. The secondary battery according to claim 1, characterized in that W ≤ 2 × S × T1.
  3. The secondary battery according to claim 1, characterized in that S × T 1/400 ≤ W ≤ S × T 1/2 .
  4. Satisfying at least one of the following conditions: (a) 0.05≦S≦10, (b) The secondary battery according to claim 1, characterized in that 0.02 ≤ W ≤ 0.5.
  5. The OI value of the negative electrode plate and S satisfy S/OI ≤ 0.5. The secondary battery according to claim 1, characterized in that, here, the OI value = C 004 / C 110 , where C 004 is the peak area obtained from the (004) plane diffraction pattern in the X-ray diffraction pattern, and C 110 is the peak area obtained from the (110) plane diffraction pattern in the X-ray diffraction pattern.
  6. The secondary battery according to claim 5, characterized in that 0.005 ≤ S/OI ≤ 0.03 and 8 ≤ OI ≤ 25.
  7. An adhesive layer is provided on the surface of the separator facing the negative electrode plate, and the adhesive layer contains a polymer. The secondary battery according to claim 1, characterized in that the polymer content is 30% to 100% based on the mass of the adhesive layer.
  8. The secondary battery according to claim 7, characterized in that the adhesive force between the separator and the negative electrode plate is FN/m and F > 3.
  9. The secondary battery according to claim 7, characterized in that the thickness of the adhesive layer is T 2 μm, the depth of the groove is H μm, and H ≤ T 2 + 20.
  10. The secondary battery according to claim 9, characterized in that the cross-sectional area of the groove is A μm² , and satisfies 0.3 × (W × H) < A < 0.95 × (W × H), where 2 ≤ H ≤ 50.
  11. The secondary battery according to claim 10, characterized in that it satisfies the condition 0.35 × (W × H) < A < 0.8 × (W × H).
  12. The secondary battery according to claim 7, characterized in that the polymer comprises at least one of the following: polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, styrene-butadiene copolymer, polyacrylonitrile, butadiene-acrylonitrile polymer, polyacrylic acid, polyacrylic acid ester, and acrylic acid ester-styrene copolymer.
  13. Along the width direction of the negative electrode plate, the groove portion forms a structure that penetrates the negative electrode plate. Herein, the groove includes a first segment having a width W1 and a second segment having a width W2 , and the secondary battery according to claim 1 satisfies 1.2 < W1 / W2 < 1.8.
  14. The secondary battery according to claim 1, characterized in that the groove forms a structure that does not penetrate the negative electrode plate along the width direction of the negative electrode plate.
  15. An electronic device characterized by comprising a secondary battery as described in any one of claims 1 to 14.

Description

This application relates to the field of electrochemical technology, and more particularly to secondary batteries and electronic equipment. Rechargeable batteries, such as lithium-ion batteries, possess characteristics such as high specific energy, high operating voltage, low self-discharge rate, small volume, and light weight, and are widely used in the field of electronic consumption. With the widespread application of lithium-ion batteries, market demands for their performance are increasing. During repeated charge-discharge cycles, lithium-ion batteries can experience internal stress accumulation and deformation. This can lead to the battery's thickness exceeding standard limits, accelerating cycle decay and affecting its cycle stability. Furthermore, as heat accumulates within the lithium-ion battery during the cycle process, if this heat cannot be released in a timely manner, the risk of thermal runaway increases, impacting the battery's safety. The drawings described herein constitute part of this application and are intended to provide a further understanding of this application. The schematic embodiments and descriptions herein are interpretive and not limiting of this application. This is a schematic diagram of the structure of an electrode assembly in some embodiments of this application. This is a schematic diagram of the cross-sectional structure of an electrode assembly along its own thickness direction in some embodiments of this application. This is a schematic diagram of the cross-sectional structure of the negative electrode plate along its own thickness direction in some embodiments of this application. This is a plan view of the negative electrode plate along its own thickness direction in some embodiments of this application. This is a schematic diagram of the cross-sectional structure of a separator along its own thickness direction in some embodiments of this application. This is a schematic diagram of the structure of a separator as observed from its own thickness direction in several other embodiments of this application. This is a schematic diagram of the structure of the groove in the negative electrode plate in some embodiments of this application. This is a schematic diagram of the structure of a groove in some other embodiments of this application. A schematic diagram of the structure of a groove in a negative electrode plate in some further embodiments of this application. To further clarify the purpose, technical proposal, and advantages of this application, the application will be described in more detail below with reference to the drawings, including examples. Clearly, the examples described are only a selection of, and not all, examples of, this application. All other examples that a person skilled in the art could make without ingenuity based on the examples in this application fall within the scope of protection sought by this application. While this application describes lithium-ion batteries as an example of secondary batteries in specific embodiments, the secondary batteries described in this application are not limited to lithium-ion batteries. Specific methods are as follows: The first invention of this application provides a secondary battery, which, as shown in Figure 1, comprises an electrode assembly 10, where the X direction is the longitudinal direction of the electrode assembly 10, the Y direction is the width direction of the electrode assembly 10, and the Z direction is the thickness direction of the electrode assembly 10. As shown in Figure 2, the electrode assembly 10 includes a positive electrode plate 20, a negative electrode plate 30, and a separator 40, the separator 40 being provided between the positive electrode plate 20 and the negative electrode plate 30, the positive electrode plate 20 including a positive electrode current collector 21 and a positive electrode active material layer 22, and the negative electrode plate 30 including a negative electrode current collector 31 and a positive electrode active material layer 32, the negative electrode active material layer 32 having grooves 321 on the surface facing the positive electrode plate 20. As shown in Figures 3 and 4, the width of the grooves 321 is W mm and the pitch of the grooves 321 is S mm. As shown in Figure 1, the thickness of the electrode assembly 10 is T 1 mm, and W ≥ S × T 1/1000 . In this application, the width of the groove means the width of the groove on the surface of the negative electrode plate, and the pitch of the groove means the distance between two adjacent grooves. In this application, the negative electrode active material layer 32 may be provided on one side or on both sides. This application allows for adjustment of the contact area between the negative electrode plate surface and the separator according to lithium-ion batteries of different thicknesses by controlling the groove width, groove pitch, and electrode assembly thickness within the scope of this applicat