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CN-224217664-U - Diaphragm, battery core structure and lithium battery

CN224217664UCN 224217664 UCN224217664 UCN 224217664UCN-224217664-U

Abstract

The utility model provides a diaphragm, a battery cell structure and a lithium battery, wherein the diaphragm comprises a base film, a ceramic layer covered on the surface of the base film and a glue layer covered on the outer side of the ceramic layer, the ceramic layer comprises a main body area and a thickening area which are connected with each other, the thickening area is covered on the position, close to the end part, of the base film, the main body area is provided with uniform thickness, the thickness of the thickening area is larger than that of the main body area, and the glue layer comprises a first coverage area covered on the main body area and a second coverage area covered on the thickening area. The thickening area can fill the thickness difference between the thinned area and the central area of the pole piece, solves the problem that the gap of the edge area of the cell structure is larger than that of the central area, and the thickening area structure with relatively hard ceramic layer can also make up the problem of uneven stress caused by the thinned area.

Inventors

  • DING XINYING
  • LIN LIANGWEN
  • LI MIN

Assignees

  • 孝感楚能新能源创新科技有限公司

Dates

Publication Date
20260508
Application Date
20250530

Claims (10)

  1. 1. The diaphragm is characterized by comprising a base film (1), a ceramic layer (2) covered on the surface of the base film and a glue layer (3) covered on the outer side of the ceramic layer, wherein the ceramic layer comprises a main body region (21) and a thickening region (22) which are connected with each other, the thickening region is covered on the position, close to the end part, of the base film, the main body region (21) has uniform thickness, the thickness of the thickening region (22) is larger than that of the main body region, and the glue layer comprises a first coverage region (31) covering the main body region and a second coverage region (32) covering the thickening region.
  2. 2. A membrane according to claim 1, wherein the thickened region (22) increases in thickness in a direction away from the body region.
  3. 3. A diaphragm according to claim 1, wherein the first footprint (31) has a uniform thickness and the second footprint (32) has a thickness greater than the first footprint.
  4. 4. A diaphragm according to claim 3, wherein the second footprint (32) has a gradually increasing thickness in a direction away from the first footprint (31).
  5. 5. A membrane according to claim 1, characterized in that one side of the base film (1) is provided with the ceramic layer (2) and the glue layer (3), the total thickness of the thickened region (22) and the corresponding second coverage area (32) exceeding the total thickness of the body region (21) and the corresponding first coverage area (31) by 5-20 μm.
  6. 6. A membrane according to claim 1, characterized in that the ceramic layer (2) and the glue layer (3) are provided on both sides of the base film, the total thickness of the thickened region (22) and the corresponding second coverage area (32) exceeding the total thickness of the body region (21) and the corresponding first coverage area (31) by 2-10 μm.
  7. 7. A membrane according to claim 1, wherein the ceramic layer comprises a body region (21) and two thickened regions (22) connected to respective ends of the body region.
  8. 8. A separator according to claim 1, wherein the base film (1) has a thickness of 6 to 15. Mu.m.
  9. 9. A battery cell structure is characterized by comprising a pole piece and the diaphragm according to any one of claims 1-8, wherein the pole piece comprises a foil (4) and a material layer (5) covered on the surface of the foil, the material layer comprises a central region (51) and a thinned region (52), the thinned region is positioned near the end part of the material layer, the central region has uniform thickness, the thickness of the thinned region is smaller than that of the central region, at least one part of a first coverage area (31) is matched with the central region (51), and at least one part of a second coverage area (32) is matched with the thinned region (52).
  10. 10. A lithium battery comprising the cell structure of claim 9.

Description

Diaphragm, battery core structure and lithium battery Technical Field The utility model relates to the technical field of lithium batteries, in particular to a diaphragm, a battery core structure and a lithium battery. Background In lithium batteries, the separator has the primary function of separating the positive and negative plates, preventing the two plates from shorting due to contact, and allowing ions to transfer between the positive and negative plates. In the prior art, the side edge positions of the positive and negative pole plates are generally provided with a thinning area with a certain width, the thickness of the thinning area is smaller than that of the central area of the pole plate, when the battery cell pole group is assembled in a positive pole-diaphragm-negative pole structure, the gap between the thinning area of the pole plate and the diaphragm is larger than that between the central area and the diaphragm, the lithium ion shuttle path of the thinning area is long, and the lithium ion shuttle path is easy to cause lithium precipitation phenomenon because of lack of electrolyte, so that certain influence is caused on the battery performance. Patent document CN202023231785.3 discloses a non-uniform glue-spreading diaphragm and a battery with the diaphragm, the non-uniform glue-spreading diaphragm comprises a diaphragm substrate and a colloid layer coated on the diaphragm substrate, the colloid layer comprises a basic area and a compensation area, the compensation area is arranged at two ends of the diaphragm substrate, the basic area is arranged between two compensation areas and connected with the compensation area, and the thickness of the compensation area is larger than that of the basic area. In the scheme, the thickening structure of the compensation region compensates the influence of gaps brought by the thinning region to a certain extent, so that the consistency of the cell structure is enhanced, but the rigidity of the adhesive layer is insufficient, and the problem of uneven stress of the thinning region and the central region cannot be well solved. Disclosure of utility model In order to solve the problems, the utility model provides a diaphragm which can make up the defects brought by the thinning area of the pole piece in terms of electrical property and mechanical property and improve the performance and the safety of a battery. In order to achieve the above purpose, the present utility model adopts the following technical scheme: The utility model provides a diaphragm, includes the base film, cover in ceramic layer of base film surface and cover in the glue film of ceramic layer outside, the ceramic layer includes interconnect's main part district and thickening district, the thickening district cover in the position near the tip of base film, the main part district has even thickness, the thickness of thickening district is greater than the main part district, the glue film includes the cover the first coverage area of main part district and the cover the second coverage area of thickening district. Further, the thickened region gradually increases in thickness in a direction away from the body region. Further, the first footprint has a uniform thickness, and the second footprint has a thickness greater than the first footprint. Further, the second coverage area gradually increases in thickness in a direction away from the first coverage area. Further, the ceramic layer and the adhesive layer are arranged on one side of the base film, and the total thickness of the thickening area and the corresponding second coverage area exceeds the total thickness of the main body area and the corresponding first coverage area by 5-20 micrometers. Further, the ceramic layer and the adhesive layer are arranged on two sides of the base film, and the total thickness of the thickening area and the corresponding second coverage area exceeds the total thickness of the main body area and the corresponding first coverage area by 2-10 micrometers. Further, the ceramic layer comprises a main body region and two thickening regions, and the two thickening regions are respectively connected with two ends of the main body region. Further, the thickness of the base film is 6-15 mu m. Another object of the present utility model is to provide a cell structure, which includes a pole piece and a diaphragm, the pole piece includes a foil and a layer covered on the surface of the foil, the layer includes a central region and a thinned region, the thinned region is located near an end of the layer, the central region has a uniform thickness, the thinned region has a thickness smaller than that of the central region, at least a portion of the first coverage region is matched with the central region, and at least a portion of the second coverage region is matched with the thinned region. Another object of the present utility model is to provide a lithium battery, which includes the above-mentioned cell str