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EP-4517910-B1 - STACKED BATTERY CELL AND LITHIUM ION BATTERY

EP4517910B1EP 4517910 B1EP4517910 B1EP 4517910B1EP-4517910-B1

Inventors

  • ZHANG, JIAN
  • PENG, Chong

Dates

Publication Date
20260506
Application Date
20230307

Claims (11)

  1. A laminated battery cell, comprising an electrode sheet assembly (1) and a protection assembly (2), wherein the protection assembly (2) is located on a surface of an outer electrode sheet of the electrode sheet assembly (1); the electrode sheet assembly (1) comprises at least one functional electrode sheet (101), the functional electrode sheet (101) comprises a first current collector (1011), a first protective layer (1012) and a first active layer (1013), and the first protective layer (1012) is located between the first current collector (1011) and the first active layer (1013); the protection assembly (2) comprises a second current collector (2011) and a second protective layer (2012), and the second protective layer (2012) is away from the electrode sheet assembly (1); wherein the first protective layer (1012) comprises a conductive particle and a binder; the conductive particle is an inorganic filler with a conductive coating layer on its surface; the conductive coating layer accounts for 2% to 40% of a mass content of the conductive particle; and a thickness of the first protective layer (1012) is 1µm to 10µm; characterized in that the second protective layer (2012) comprises a conductive particle and a binder; the conductive particle is an inorganic filler with a conductive coating layer on its surface; the conductive coating layer accounts for 2% to 40% of a mass content of the conductive particle; and a thickness of the second protective layer (2012) is 1µm to 10µm.
  2. The laminated battery cell according to claim 1, wherein at least a portion of the conductive coating layer constitutes an outermost layer of the conductive particle.
  3. The laminated battery cell according to claim 1 or 2, wherein the conductive coating layer covers at least a portion of the inorganic filler.
  4. The laminated battery cell according to any one of claims 1 to 3, wherein a thickness of the first protective layer (1012) is A, a thickness of the second protective layer (2012) is B, and A is less than or equal to B.
  5. The laminated battery cell according to any one of claims 1 to 4, wherein the first protective layer (1012) and the second protective layer (2012) each independently comprise 40% to 98% of the conductive particle, 2% to 30% of the binder, and 0% to 40% of a non-conductive particle by mass content.
  6. The laminated battery cell according to any one of claims 1 to 5, wherein the first protective layer (1012) and the second protective layer (2012) each independently have a resistance of 10-2000mΩ.
  7. The laminated battery cell according to any one of claims 1 to 5, wherein a resistivity of the conductive particle is 1 to 100Ω•cm.
  8. The laminated battery cell according to any one of claims 1 to 5, wherein an average particle size of the conductive particle is 0.05-5µm.
  9. The laminated battery cell according to claim 1, wherein the conductive coating layer comprises at least one of tin oxide, indium oxide, ATO, FTO, ITO, and carbon material.
  10. The laminated battery cell according to any one of claims 6 to 9, wherein the inorganic filler comprises at least one of aluminum oxide, magnesium oxide, titanium oxide, zinc oxide, silicon oxide, boehmite, cobalt oxide, iron phosphate, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium iron manganese phosphate.
  11. A lithium-ion battery, comprising the laminated battery cell according to any one of claims 1 to 10.

Description

TECHNICAL FIELD The present application belongs to the field of lithium-ion battery, and specifically relates to a laminated battery cell and a lithium-ion battery. BACKGROUND Lithium-ion batteries must undergo mechanical abuse testing before they can be applied to actual scenarios. Mechanical abuse testing refers to testing the performance of batteries under simulated extreme conditions, such as extrusion testing, puncture testing, etc. Lithium-ion battery has a high probability of failure during mechanical abuse testing, and the reason is that when the battery is subjected to mechanical damage, a serious short circuit will occur internally. For example, a short circuit occurs when a current collector contacts with a current collector of the adjacent electrode sheet, when an active layer contacts with an active layer of the adjacent electrode sheet, or when a current collector contacts with an active layer of the adjacent electrode sheet, causing thermal runaway. Therefore, how to improve the safety performance of lithium-ion batteries is a technical problem that needs to be solved urgently in this field. US 2005/100782 Al discloses a lithium secondary battery exhibiting the improved function of self safety in an abnormal state without sacrificing battery characteristics. To attain the object, in a lithium secondary battery comprising a positive electrode, a negative electrode, an electrolytic solution, and a separator, a plurality of positive electrodes and negative electrodes are arranged to construct an electrode structure which includes an outermost layer of electrode on which a back coat layer is formed. CN 114156429 A discloses an electrode sheet and a lithium-ion battery. In a first aspect, the disclosure provides an electrode sheet, which includes a substrate. The substrate comprises a current collector and a protective layer disposed on the surface of the current collector, and an active material layer is further provided on the protective layer; according to mass percentage, the protective layer consists of 62%-97% inactive material, 0.1%-8% conductive agent, and 3%-30% binder, with a resistivity of 500-5000 Ω·cm. SUMMARY The present invention is set out in the appended set of claims. The present application provides a laminated battery cell, which can prevent the internal short circuit of the lithium-ion battery during mechanical abuse by arrangement of a first protective layer and a second protective layer, so that the lithium-ion battery has excellent safety performance. The present application also provides a lithium-ion battery, which has good safety performance because it includes the above-mentioned laminated battery cell. In one aspect of the present application, a laminated battery cell is provided, including an electrode sheet assembly and a protection assembly, where the protection assembly is located on a surface of an outer electrode sheet of the electrode sheet assembly; the electrode sheet assembly includes at least one functional electrode sheet, the functional electrode sheet includes a first current collector, a first protective layer and a first active layer, and the first protective layer is located between the first current collector and the first active layer; the protection assembly includes a second current collector and a second protective layer, and the second protective layer is away from the electrode sheet assembly; the first protective layer and the second protective layer each independently includes a conductive particle and a binder; the conductive particle is an inorganic filler with a conductive coating layer on its surface, the conductive coating layer accounts for 2% to 40% of a mass content of the conductive particle, and a thickness of the first protective layer and a thickness of the second protective layer are each greater than 0.5µm. According to one embodiment of the present application, at least a portion of the conductive coating layer constitutes an outermost layer of the conductive particle. According to one embodiment of the present application, the conductive coating layer covers at least a portion of the inorganic filler. According to one embodiment of the present application, a thickness of the first protective layer is A, a thickness of the second protective layer is B, and A is less than or equal to B. According to one embodiment of the present application, the thickness of the first protective layer and the thickness of the second protective layer are each independently 1µm to 10µm. According to one embodiment of the present application, the first protective layer and the second protective layer each independently includes 40% to 98% of the conductive particle, 2% to 30% of the binder, and 0% to 40% of the non-conductive particle by mass content. According to an embodiment of the present application, the first protective layer and the second protective layer each independently have a resistance of 10-2000mΩ; and/or the resistivity of the conduc