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EP-4386898-B1 - SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRIC APPARATUS

EP4386898B1EP 4386898 B1EP4386898 B1EP 4386898B1EP-4386898-B1

Inventors

  • ZHANG, Limei
  • CHEN, PEIPEI
  • JIANG, Yao
  • LIU, Jiao

Dates

Publication Date
20260506
Application Date
20220401

Claims (17)

  1. A secondary battery (5), comprising a positive electrode plate and a non-aqueous electrolyte solution, wherein the positive electrode plate comprises a positive electrode active material, the positive electrode active material comprises an inner core and a shell cladding the inner core, and the inner core comprises Li 1+x Mn 1-y AyP 1-z R z O 4 , wherein x=-0.100-0.100, y=0.001-0.500, z=0.001-0.100, A is selected from one or more elements in a group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and optionally one or more elements in a group consisting of Fe, Ti, V, Ni, Co and Mg, and R is selected from one or more elements in a group consisting of B, Si, N and S; the shell comprises a first cladding layer cladding the inner core, and a second cladding layer cladding the first cladding layer, wherein the first cladding layer comprises pyrophosphate MP 2 O 7 and phosphate XPO 4 , wherein M and X are each independently selected from one or more elements in a group consisting of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al, and the second cladding layer comprises carbon, wherein a weight ratio of pyrophosphate to phosphate in the first cladding layer is from 1:3 to 3:1, and wherein the first cladding layer has a coating amount of greater than 0 and less than or equal to 7 wt.%, based on the weight of the core and the second cladding layer has a coating amount of greater than 0 and less than or equal to 6 wt.%, based on the weight of the core; the non-aqueous electrolyte solution comprises a first additive, and the first additive comprises one or more compounds in a group consisting of a compound shown in Formula 1, a compound shown in Formula 2 and a compound shown in Formula 3: R 1 and R 2 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl and C6-C10 aryl, and at least one of R1 and R2 represents any one of F or C1-C6 fluoroalkyl; R 3 and R 4 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl and C2-C6 alkynyl, and at least one of R 3 and R 4 represents any one of F or C1-C6 fluoroalkyl; R 5 and R 6 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, carbonyl, O - , =O, - - BF 3 and -O-BF 3 ; M in each chemical formula each independently represents one of alkali metals and alkalineearth metals; and n is 0, 1 or 2, wherein the crystallinity of pyrophosphate and phosphate is each independently 10% to 100%.
  2. The secondary battery (5) according to claim 1, wherein R 1 and R 2 each independently represent any one of F, C1-C3 fluoroalkyl, C1-C3 alkyl, C1-C3 alkoxy, C2-C3 alkenyl, C2-C3 alkynyl, phenyl, benzyl and methylphenyl, and at least one of R1 and R2 represents any one of F or C1-C3 fluoroalkyl; optionally, R 1 and R 2 each independently represent any one of F, C1-C3 alkyl and C1-C3 fluoroalkyl; optionally, the C1-C3 fluoroalkyl is - CF 3 , -C 2 F 5 , -CH 2 CF 3 or -CF 2 CH 3 , and the C 1 -C 3 alkyl is methyl or ethyl; and/or R 3 and R 4 each independently represent any one of F, C1-C3 fluoroalkyl, C1-C3 alkyl, C1-C3 alkoxy, C2-C3 alkenyl and C2-C3 alkynyl, and at least one of R 3 and R 4 represents any one of F and C1-C3 fluoroalkyl; optionally, R 3 and R 4 independently represent any one of F and C1-C3 fluoroalkyl; and/or R 5 and R 6 each independently represent any one of F, C1-C3 fluoroalkyl, C1-C3 alkyl, C1-C3 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, carbonyl, O-, =O, - - BF 3 and -O - BF 3 ; optionally, R5 and R6 independently represent any one of F, fluoromethyl, methyl, O - , =O, - - BF 3 and -O - BF 3 , and n is 0 or 1; and/or M in each chemical formula each independently represents one of Li, Na and K.
  3. The secondary battery (5) according to claim 1 or 2, wherein the first additive comprises one or more of the following compounds:
  4. The secondary battery (5) according to any one of claims 1 to 3, wherein the first additive comprises any one or more of the following compounds:
  5. The secondary battery (5) according to any one of claims 1 to 4, wherein the non-aqueous electrolyte solution further comprises a second additive, and the second additive comprises one or more of compounds in a group consisting of a cyclic carbonate compound containing unsaturated bonds, a halogen-substituted cyclic carbonate compound, a sulfate compound, a sulfite compound, a sultone compound, a disulfonic acid compound, a nitrile compound, an aromatic compound, an isocyanate compound, a phosphazene compound, a cyclic anhydride compound, a phosphite compound, a phosphate compound and a borate compound.
  6. The secondary battery (5) according to claim 5, wherein based on the total weight of the non-aqueous electrolyte solution, the content of the first additive is W1 wt%, and W1 is 0.01 to 20, and optionally 0.1 to 10 or 0.5 to 5; and/or the content of the second additive is W2 wt%, and W2 is 0.01 to 20, and optionally 0.1 to 10 or 0.3 to 5; optionally, the W1/W2 is defined as M, and M is 0.001 to 20, and optionally 0.1 to 10.
  7. The secondary battery (5) according to any one of claims 1 to 6, wherein the non-aqueous electrolyte solution further comprises an organic solvent and an electrolyte salt, optionally, the organic solvent comprises one or more of a cyclic carbonate compound, a chain carbonate compound and a carboxylate compound, and further comprises one or more components in a group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, ethylene carbonate, propylene carbonate, butene carbonate, gamma-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, butyl propionate and tetrahydrofuran; and/or optionally, the electrolyte salt comprises one or more components in a group consisting of LiN(C x F2 x+1 SO 2 )(C y F 2y+1 SO 2 ), Li(FSO 2 ) 2 N, LiCF 3 SO 3 , LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiBOB, LiDFOB and LiTFOP, x and y represent positive integers, optionally, x and y are each independently 0, 1, 2 or 3, and the concentration range of the electrolyte salt in the non-aqueous electrolyte solution is 0.5 M to 2.5 M, and optionally 0.8 M to 2 M.
  8. The secondary battery (5) according to any one of claims 1 to 7, wherein based on the weight of the inner core, the cladding amount of the first cladding layer is C1 wt%, and C1 is greater than 0 and less than or equal to 7, and optionally 4 to 5.6; and/or based on the weight of the inner core, the cladding amount of the second cladding layer is C2 wt%, and C2 is greater than 0 and less than or equal to 6, and optionally 3 to 5.
  9. The secondary battery (5) according to claim 4, wherein based on the weight of the inner core, the cladding amount of the first cladding layer is C1 wt%, and C1 is greater than 0 and less than or equal to 7, and optionally 4 to 5.6; and/or based on the weight of the inner core, the cladding amount of the second cladding layer is C2 wt%, and C2 is greater than 0 and less than or equal to 6, and optionally 3 to 5; wherein the relational expression W1/(C1+C2) between the content W1 of the first additive and the cladding amount C1 of the first cladding layer as well as the cladding amount C2 of the second cladding layer is C, and C is 0.001 to 2, and optionally 0.01 to 1.
  10. The secondary battery (5) according to any one of claims 1 to 9, wherein the weight ratio of pyrophosphate to phosphate in the first cladding layer is 1:3 to 1:1.
  11. The secondary battery (5) according to any one of claims 1 to 10, wherein the interplanar spacing of phosphate in the first cladding layer is 0.345 to 0.358 nm, and an included angle between crystal orientations (111) is 24.25° to 26.45°; and the interplanar spacing of pyrophosphate in the first cladding layer is 0.293 to 0.326 nm, and an included angle between crystal orientations (111) is 26.41° to 32.57°; wherein the interplanar spacing and the included angle between crystal orientations (111) are measured as described in the description; and/or wherein in the inner core, the ratio of y to 1-y is 1:10 to 10:1, and optionally 1:4 to 1:1; and/or in the inner core, the ratio of z to 1-z is 1:9 to 1:999, and optionally 1:499 to 1:249; and/or wherein the crystallinity of pyrophosphate and phosphate is each independently 50% to 100%.
  12. The secondary battery (5) according to any one of claims 1 to 11, wherein A is selected from at least two of Fe, Ti, V, Ni, Co and Mg.
  13. The secondary battery (5) according to any one of claims 1 to 12, wherein the Li/Mn antisite defect concentration of the positive electrode active material is 4% or less, and optionally 2% or less, wherein the Li/Mn antisite defect concentration is measured as described in the description; or wherein the lattice change rate of the positive electrode active material is 6% or less, and optionally 4% or less, wherein the lattice change rate is measured as described in the description.
  14. The secondary battery (5) according to any one of claims 1 to 13, wherein the surface oxygen valence state of the positive electrode active material is -1.88 or less, and optionally -1.98 to -1.88, wherein the surface oxygen valence state is measured as described in the description; and/or wherein the compacted density of the positive electrode active material at 3 tons (T) is 2.0 g/cm 3 or more, and optionally 2.2 g/cm 3 or more, wherein the compacted density is measured as described in the description.
  15. A battery module (4), comprising the secondary battery (5) according to any one of claims 1 to 14.
  16. A battery pack (1), comprising the battery module (4) according to claim 15.
  17. An electrical apparatus, comprising at least one of the secondary battery (5) according to any one of claims 1 to 14, the battery module (4) according to claim 15, or the battery pack (1) according to claim 16.

Description

Technical Field The present application relates to the technical field of lithium batteries, and in particular to a secondary battery as specified in any of claims 1-14, a battery module as specified in claim 15, a battery pack as specified in claim 16, and an electrical apparatus as specified in claim 17. Background In recent years, with the increasingly wide use of lithium-ion batteries, lithium-ion batteries are widely used in energy storage power systems such as water power, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have also been put forward for their energy density, cycling performance and safety performance. US2016190584A1 mentions a Li-ion battery positive electrode material. CN103872320A mentions a composite positive electrode material. CN109301174A mentions a positive electrode material with a core-shell structure. CN101339994A mentions a multi doped lithium iron phosphate cathode material. US2019355983A1 mentions a lithium-ion battery. WO2018032569A1 mentions a cathode material having a core-shell structure. Compared with other positive electrode active materials, a lithium manganese phosphate positive electrode active material has higher safety and cycle life, but the lithium manganese phosphate has the disadvantage of poor rate performance. At present, this problem is usually solved by means of cladding or doping. However, it is still hoped to further increase the rate performance, cycling performance, high temperature stability and the like of the lithium manganese phosphate positive electrode active material. Summary of the Invention The present invention is defined by the appended claims. The present application is conducted in view of the above problem, and aims to provide a secondary battery, a battery module, a battery pack and an electrical apparatus to solve the problems of poor rate performance and cycling performance of lithium manganese phosphate secondary batteries. In order to achieve the above objectives, a first aspect of the present application provides a secondary battery, including a positive electrode plate and a non-aqueous electrolyte solution. A positive electrode active material includes an inner core and a shell cladding the inner core. The inner core includes Li1+xMn1-yAyP1-zRzO4, where x=-0.100-0.100, y=0.001-0.500, and z=0.001-0.100; A is selected from one or more elements in a group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and optionally one or more elements in a group consisting of Fe, Ti, V, Ni, Co and Mg; and R is selected from one or more elements in a group consisting of B, Si, N and S. The shell includes a first cladding layer cladding the inner core and a second cladding layer cladding the first cladding layer, where the first cladding layer includes pyrophosphate MP2O7 and phosphate XPO4, where M and X are independently selected from one or more elements in a group consisting of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al; and the second cladding layer includes carbon, wherein a weight ratio of pyrophosphate to phosphate in the first cladding layer is from 1:3 to 3:1, and wherein the first cladding layer has a coating amount of greater than 0 and less than or equal to 7 wt.%, based on the weight of the core and the second cladding layer has a coating amount of greater than 0 and less than or equal to 6 wt.%, based on the weight of the core. The non-aqueous electrolyte solution includes a first additive. The first additive includes one or more compounds in a group consisting of a compound shown in Formula 1, a compound shown in Formula 2 and a compound shown in Formula 3: R1 and R2 independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl and C6-C10 aryl, and at least one of R1 and R2 represents any one of F or C1-C6 fluoroalkyl;R3 and R4each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl and C2-C6 alkynyl, and at least one of R3 and R4 represents any one of F and C1-C6 fluoroalkyl;R5 and R6 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, carbonyl, O-, =O, --BF3 and -O-BF3;M in each chemical formula each independently represents one of alkali metals and alkaline-earth metals; andn is 0, 1 or 2 wherein in the first positive electrode active material, the crystallinity of pyrophosphate and phosphate is independently 10% to 100. Unless otherwise specified, in the above chemical formula, when A includes two or more elements, the definition for the value range of y is not only a definition for the stoichiometric number of each element as A, but also a definition for the sum of the stoichiometric numbers of various elements as