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CN-122025801-A - Electrolyte, lithium ion battery and electric equipment

CN122025801ACN 122025801 ACN122025801 ACN 122025801ACN-122025801-A

Abstract

The application provides electrolyte, a lithium ion battery and electric equipment, and relates to the field of lithium ion batteries. The electrolyte comprises a solvent, wherein the solvent comprises cyclic carbonate and linear carbonate, the cyclic carbonate is PC, the linear carbonate comprises EMC and DMC, and the mass ratio of PC to EMC to DMC is (14-15) (5.5-6.5) (54-56). The electrolyte does not contain EC, and can form a denser and more stable interface film by matching the specific content with the specific type of solvent, thereby remarkably improving the high-temperature cycle performance of the battery, inhibiting the gas production phenomenon and obtaining unexpected high-temperature low-gas production effect.

Inventors

  • Kaoshikeshuban
  • Gai Jingjing

Assignees

  • 深圳市比克动力电池有限公司

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. An electrolyte comprising a solvent, the solvent comprising a cyclic carbonate and a linear carbonate; the cyclic carbonate is PC, and the linear carbonate includes EMC and DMC; The mass ratio of the PC to the EMC to the DMC is (14-15) (5.5-6.5) (54-56).
  2. 2. The electrolyte according to claim 1, wherein the content of PC is 14 to 15wt%, the content of EMC is 5.5 to 6.5wt%, and the content of DMC is 54 to 56wt%, based on the total mass of the electrolyte.
  3. 3. The electrolyte of claim 1, wherein the electrolyte further comprises a lithium salt; the lithium salt includes LiPF 6 .
  4. 4. The electrolyte according to claim 3, wherein the content of the lithium salt in the electrolyte is 14-15 wt%.
  5. 5. The electrolyte of claim 1 further comprising an additive, the additive comprising at least one of FEC, liPO 2 F 2 , TMSP, liDFOB, TPP, PST.
  6. 6. The electrolyte of claim 5 wherein the additive is present in the electrolyte in an amount of 5 to 12.5wt%.
  7. 7. The electrolyte according to claim 5, wherein the FEC is contained in an amount of 5-10wt% in the electrolyte; And/or the content of LiPO 2 F 2 in the electrolyte is 0-0.5wt%; and/or the TMSP content in the electrolyte is 0-0.5wt%; and/or the content of the LiDFOB in the electrolyte is 0-0.5wt%; and/or the content of the TPP in the electrolyte is 0-0.5wt%; and/or the PST is contained in the electrolyte in an amount of 0-0.5wt%.
  8. 8. A lithium ion battery comprising the electrolyte of any one of claims 1-7.
  9. 9. The lithium ion battery of claim 8, further comprising a positive electrode, a negative electrode; The positive electrode comprises a positive electrode active material which is LiNi x Co y Mn z L( 1-x-y-z )O 2 , wherein, L includes at least one of Al, sr, mg, ti, ca, zr, zn, si, fe, 0.9≤x <1, 0≤y≤1, 0≤z <1, 0≤x+y+z≤1.
  10. 10. An electrical device comprising a lithium ion battery as claimed in claim 8 or 9.

Description

Electrolyte, lithium ion battery and electric equipment Technical Field The application relates to the field of lithium ion batteries, in particular to electrolyte, a lithium ion battery and electric equipment. Background The high-nickel ternary positive electrode material (Ni content is more than or equal to 90%) has wide application prospect in the fields of power and energy storage due to the high specific energy characteristic. However, under the high-temperature circulation condition, the system has the common problems of electrolyte decomposition and side reaction aggravation, so that a large amount of gas is separated out, and the cell is inflated and CID is overturned in advance, so that the battery is invalid. The existing electrolyte applied to the lithium battery has the technical problems that the existing commonly used electrolyte formula generally contains higher proportion of Ethylene Carbonate (EC), and although good SEI (solid electrolyte interface) is formed on the surface of a negative electrode, the electrolyte is easily oxidized and decomposed by the surface of a positive electrode or side reaction occurs on the surface of the negative electrode in a high-temperature environment, so that gas generation is further increased. There have been studies to improve the cycle stability by introducing additives such as FEC (fluoroethylene carbonate), lipfob (lithium difluoroborate), TVSi (1, 3-propenesulfonolide), etc., but the gas production at high temperature is not negligible. Therefore, development of an electrolyte solution capable of reducing high-temperature side reactions and suppressing gas generation is important for promoting application of lithium ion batteries. Disclosure of Invention The application aims to provide an electrolyte, a lithium ion battery and an electric device so as to solve the problems. In order to achieve the above purpose, the application adopts the following technical scheme: an electrolyte comprising a solvent comprising a cyclic carbonate and a linear carbonate; the cyclic carbonate is PC, and the linear carbonate includes EMC and DMC; The mass ratio of the PC to the EMC to the DMC is (14-15) (5.5-6.5) (54-56). According to the embodiment of the application, the content of PC is 14-15 wt%, the content of EMC is 5.5-6.5 wt% and the content of DMC is 54-56 wt% based on the total mass of the electrolyte. According to an embodiment of the application, the electrolyte further comprises a lithium salt; the lithium salt includes LiPF 6. According to the embodiment of the application, the content of the lithium salt in the electrolyte is 14-15 wt%. According to an embodiment of the application, the electrolyte further comprises an additive comprising at least one of FEC, liPO 2F2, TMSP, liDFOB, TPP, PST. According to an embodiment of the application, the additive is present in the electrolyte in an amount of 5-12.5wt%. According to an embodiment of the present application, the FEC is contained in the electrolyte in an amount of 5 to 10wt%; And/or the content of LiPO 2F2 in the electrolyte is 0-0.5wt%; and/or the TMSP content in the electrolyte is 0-0.5wt%; and/or the content of the LiDFOB in the electrolyte is 0-0.5wt%; and/or the content of the TPP in the electrolyte is 0-0.5wt%; and/or the PST is contained in the electrolyte in an amount of 0-0.5wt%. The application also provides a lithium ion battery comprising the electrolyte. According to the embodiment of the application, the lithium ion battery further comprises a positive electrode and a negative electrode; The positive electrode comprises a positive electrode active material which is LiNi xCoyMnzL(1-x-y-z)O2, wherein, L includes at least one of Al, sr, mg, ti, ca, zr, zn, si, fe, 0.9≤x <1, 0≤y≤1, 0≤z <1, 0≤x+y+z≤1. The application also provides an electric device comprising the lithium ion battery. Compared with the prior art, the application has the beneficial effects that: The application provides an electrolyte without containing Ethylene Carbonate (EC), which solves the technical problems of more side reactions and serious gas production of the traditional electrolyte at high temperature. Specifically, the present application breaks the technical prejudice that lack of EC in the art is believed to result in the failure of the solid electrolyte interface (SEI film) to be formed effectively, thereby causing serious problems of negative electrode lithium evolution, capacity fade and gassing, by removing Ethylene Carbonate (EC) in the conventional electrolyte, which is regarded as a key film former. The electrolyte does not contain EC, and can form a denser and more stable interface film by matching the specific content with the specific type of solvent, thereby remarkably improving the high-temperature cycle performance of the battery, inhibiting the gas production phenomenon and obtaining unexpected high-temperature low-gas production effect. Moreover, the electrolyte of the present application does not im