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CN-116454539-B - Battery and electric equipment

CN116454539BCN 116454539 BCN116454539 BCN 116454539BCN-116454539-B

Abstract

The application belongs to the technical field of batteries, and discloses a battery and electric equipment. The battery comprises a positive electrode plate and a diaphragm, wherein the diaphragm comprises a base film and a coating which is arranged on the surface of the base film and faces the positive electrode plate, the battery is charged at 25 ℃ with a current density of 1/3C, and the SOC of the battery when the battery is overcharged and shorted is more than 130%. And the coating layer is arranged on the base film to prevent lithium dendrites from penetrating through the diaphragm, so that the overcharge resistance of the battery is improved.

Inventors

  • GENG YUE
  • LIANG ZHENJIN

Assignees

  • 欣旺达电动汽车电池有限公司

Dates

Publication Date
20260508
Application Date
20230323

Claims (7)

  1. 1. A battery comprising a positive electrode sheet and a separator, wherein the separator comprises a base film and a coating layer which is arranged on one surface of the base film and faces the positive electrode sheet, the coating layer comprises an oxidant and ceramic particles, the oxidant is a compound capable of undergoing a redox reaction with metallic lithium, the compound comprises one or a mixture of several of sodium thiosulfate, sodium hypochlorite, sodium perborate and sodium persulfate, and the ceramic particles comprise one or a mixture of several of aluminum oxide, magnesium oxide, silicon dioxide, zirconium oxide, titanium dioxide and hydrotalcite; the battery satisfies that the SOC is more than 130% when the battery is overcharged and short-circuited when the battery is charged at 25 ℃ and the current density is 1/3 ℃.
  2. 2. The battery of claim 1, wherein the battery is charged at a current density of 1/3C at 25C and has an SOC greater than or equal to 150% when overcharged.
  3. 3. The battery of claim 1, wherein the coating has a thickness of 0.5-5.0 μm.
  4. 4. The battery of claim 1, wherein the amount of oxidant per unit area in the coating is 0.05-2.5 mg/cm 2 .
  5. 5. The battery of claim 1, wherein the shrinkage of the separator in the machine direction is less than 2.5% after heat treatment at 100 ℃ for 2 hours.
  6. 6. The battery of claim 1, wherein the separator has a needling strength of 300-500gf.
  7. 7. An electrical device comprising the battery of claims 1-6.

Description

Battery and electric equipment Technical Field The application relates to the technical field of batteries, in particular to a battery and electric equipment. Background In recent years, as global warming caused by greenhouse effect is increasing, the problem of emission reduction of greenhouse gases is increasingly focused, carbon dioxide is one of the most important components of the greenhouse gases, and the policies of reducing carbon dioxide emission and promoting rapid development of green energy sources are promoted in many countries. The lithium ion battery is used as an important green energy storage mode, and has the advantages of high energy density, long cycle life and the like, so that the lithium ion battery is widely applied to the fields of intelligent electronic products, new energy automobiles and the like. In particular, in the aspect of new energy automobiles, fuel automobiles prohibit selling are planned in many countries, and the large-scale application of lithium ion batteries on the new energy automobiles is further promoted. The lithium ion battery is used as one of core components of the new energy automobile, and the safety performance of the battery influences the life safety of the new energy automobile and driving personnel. According to the current statistics, most of the electric car fire accidents are related to the battery, wherein more than 35% of the battery related accidents are related to the overcharge of the battery. A series of problems are caused by the increase of polarization during the overcharge of the battery, wherein lithium is deposited on the anode to form lithium dendrites, and the lithium dendrites pierce the separator to cause short circuit, and finally even cause dangerous accidents such as fire or explosion. Disclosure of Invention Therefore, the embodiment of the application provides a battery and electric equipment, which aim to improve the overcharge resistance of the battery, block lithium dendrites from penetrating through a diaphragm and improve the safety performance of a lithium ion battery. In a first aspect, the present application provides a battery. The application is realized by the following technical scheme: A battery comprises a positive electrode plate and a diaphragm, wherein the diaphragm comprises a base film and a coating layer which is arranged on the surface of the base film and faces to the positive electrode plate, the battery is charged at 25 ℃ with a current density of 1/3C, and the SOC of the battery when the battery is overcharged and shorted is more than 130%. In a preferred example of the present application, it may be further arranged that the battery satisfies that the SOC at the time of overcharge short-circuiting of the battery is 150% or more when charged at 25 ℃ with a current density of 1/3 ℃. In a preferred embodiment of the application, the coating may further comprise an oxidizing agent, which comprises a compound capable of undergoing a redox reaction with metallic lithium. In a preferred embodiment of the present application, the compound capable of undergoing a redox reaction with metallic lithium may further include one or more of sodium thiosulfate, sodium hypochlorite, sodium perborate, iodine and sodium persulfate. In a preferred embodiment of the present application, the coating layer may further include ceramic particles, wherein the ceramic particles include one or more of alumina, magnesia, silica, zirconia, titania and hydrotalcite. In a preferred embodiment of the present application, the thickness of the coating layer may be 0.5-5.0 μm. In a preferred embodiment of the present application, the content of the oxidizing agent per unit area in the coating layer may be further set to 0.05-2.5mg/cm 2. In a preferred example of the present application, it may be further arranged that the shrinkage rate of the separator in the longitudinal direction is less than 2.5% after the heat treatment of the separator at 100 ℃ for 2 hours. In a preferred example of the present application, the separator may be further provided to have a needling strength of 300 to 500gf. In a second aspect, the present application provides a powered device. The application is realized by the following technical scheme: A powered device comprising a battery as described in the first aspect. In summary, compared with the prior art, the technical scheme provided by the embodiment of the application has the beneficial effects that the coating facing the positive electrode plate is arranged on the surface of the base film, so that the SOC (state of charge) of the battery is more than 130% when the battery is charged at 25 ℃ and the current density of 1/3 is used for charging and short-circuiting. The coating with a certain thickness is coated on the surface of the base film, so that the thermal stability of the diaphragm can be ensured, the diaphragm can maintain good structural stability when the overcharge temperature of the lithium io