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JP-7856113-B2 - secondary battery

JP7856113B2JP 7856113 B2JP7856113 B2JP 7856113B2JP-7856113-B2

Inventors

  • 井原 将之

Assignees

  • 株式会社村田製作所

Dates

Publication Date
20260511
Application Date
20221223
Priority Date
20211224

Claims (10)

  1. A positive electrode containing a positive electrode active material layer, A negative electrode containing a negative electrode active material layer, A separator and a heat-resistant layer are disposed between the positive electrode and the negative electrode. The system comprises an electrolyte solution containing an electrolyte salt, The heat-resistant layer is arranged in a region where at least the positive electrode active material layer and the negative electrode active material layer face each other, and has a melting point or decomposition temperature higher than the melting point or decomposition temperature of the separator. The electrolyte salt comprises an imid anion, and the imid anion comprises at least one of a first imid anion represented by formula (1) and a second imid anion represented by formula (2). The electrolyte further comprises lithium hexafluoride phosphate, The electrolyte salt comprises a cation and the imid anion, The lithium hexafluoride phosphate comprises lithium ions and hexafluoride phosphate ions. The sum of the cation content in the electrolyte and the lithium ion content in the electrolyte is 0.7 mol/kg or more and 2.2 mol/kg or less. The ratio of the number of moles of the hexafluoride phosphate ion in the electrolyte to the number of moles of the imido anion in the electrolyte is 13 mol% or more and 6000 mol% or less. The electrolyte further comprises at least one of the following: unsaturated cyclic carbonate esters, fluorinated cyclic carbonate esters, disulfonic anhydrides, sulfate esters, nitrile compounds, and isocyanate compounds. Secondary battery. (Each of R1 and R2 is either a fluorine group or a fluorinated alkyl group. Each of W1, W2, and W3 is either a carbonyl group (>C=O), a sulfinyl group (>S=O), or a sulfonyl group (>S(=O) ² ).) (R3 and R4 are each fluorine groups. X1, X2, X3, and X4 are each one of the following: a carbonyl group, a sulfinyl group, or a sulfonyl group. )
  2. The heat-resistant layer contains a polymer compound, The polymer compound includes at least one of the following: polyamide, polystyrene, polyacrylic acid ester, polymethacrylic acid ester, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, polytetrafluoroethylene, polyimide, polyetherimide, melamine, benzoguanamine, and polytetrafluoroethylene. The secondary battery according to claim 1.
  3. The heat-resistant layer contains an oxide, The oxide comprises at least one of aluminum oxide, titanium oxide, silicon oxide, and zirconium oxide. The secondary battery according to claim 1.
  4. The heat-resistant layer further comprises a polymer compound that retains the oxide, The polymer compound includes at least one of the following: polyamide, polystyrene, polyacrylic acid ester, polymethacrylic acid ester, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, polytetrafluoroethylene, polyimide, polyetherimide, melamine, benzoguanamine, polytetrafluoroethylene, and polyvinylidene fluoride. The secondary battery according to claim 3.
  5. The heat-resistant layer is provided in the separator. A secondary battery according to any one of claims 1 to 4.
  6. The aforementioned electrolyte salt contains light metal ions as cations. A secondary battery according to any one of claims 1 to 4.
  7. The aforementioned light metal ions include lithium ions. The secondary battery according to claim 6.
  8. The content of the electrolyte salt in the electrolyte solution is 0.2 mol/kg or more and 2 mol/kg or less. A secondary battery according to any one of claims 1 to 4.
  9. The electrolyte further comprises at least one of lithium hexafluoride phosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalato)borate, and lithium difluorophosphate. A secondary battery according to any one of claims 1 to 4.
  10. Lithium-ion rechargeable batteries, A secondary battery according to any one of claims 1 to 4.

Description

This technology relates to secondary batteries. With the widespread use of various electronic devices such as mobile phones, development of rechargeable batteries is progressing as a power source that is small, lightweight, and provides high energy density. These rechargeable batteries contain an electrolyte along with a positive electrode and a negative electrode, and various studies are being conducted on the configuration of these batteries. Specifically, the electrolyte contains an imide compound represented as R F 1 - S(=O) 2 - NH - S(=O) 2 - NH - S(=O) 2 - R F 2 (see, for example, Patent Document 1). Furthermore, the electrolyte salt of the electrolyte contains an imide anion represented as F - S(=O) 2 - N - - C(=O) - N - - S(=O) 2 - F or F - S(=O) 2 - N - - S(=O) 2 - C 6 H 4 - S(=O) 2 - N - - S(=O) 2 - F (see, for example, Non-Patent Documents 1 and 2). Chinese Patent No. 102786443 Specification Faiz Ahmed et al., “Novel divalent organo-lithium salts with high electrochemical and thermal stability for aqueous rechargeable Li-Ion batteries”, Electrochimica Acta, 298, 2019, 709-716Faiz Ahmed et al., “Highly conductive divalent fluorosulfonyl imide based electrolytes improving Li-ion battery performance: Additive potentiating”, Journal of Power Sources, 455, 2020, 227980 Although various studies have been conducted on the configuration of secondary batteries, their battery characteristics are still not sufficient, and there is room for improvement. There is a need for a secondary battery that can achieve excellent battery characteristics. A secondary battery according to one embodiment of this technology comprises a positive electrode including a positive electrode active material layer, a negative electrode including a negative electrode active material layer, a separator and a heat-resistant layer disposed between the positive electrode and the negative electrode, and an electrolyte containing an electrolyte salt. The heat-resistant layer is disposed in a region where at least the positive electrode active material layer and the negative electrode active material layer face each other, and has a melting point or decomposition temperature higher than the melting point or decomposition temperature of the separator. The electrolyte salt contains an imid anion, and the imid anion contains at least one of a first imid anion represented by formula (1), a second imid anion represented by formula (2), a third imid anion represented by formula (3), and a fourth imid anion represented by formula (4). (Each of R1 and R2 is either a fluorine group or a fluorinated alkyl group. Each of W1, W2, and W3 is either a carbonyl group (>C=O), a sulfinyl group (>S=O), or a sulfonyl group (>S(=O) ² ).) (Each of R3 and R4 is either a fluorine group or a fluorinated alkyl group. Each of X1, X2, X3, and X4 is either a carbonyl group, a sulfinyl group, or a sulfonyl group.) (R5 is a fluorinated alkylene group. Y1, Y2, and Y3 are each one of a carbonyl group, a sulfinyl group, or a sulfonyl group.) (Each of R6 and R7 is either a fluorine group or a fluorinated alkyl group. R8 is either an alkylene group, a phenylene group, a fluorinated alkylene group, or a fluorinated phenylene group. Each of Z1, Z2, Z3, and Z4 is either a carbonyl group, a sulfinyl group, or a sulfonyl group.) According to one embodiment of the secondary battery of this technology, a separator and a heat-resistant layer are arranged between the positive electrode and the negative electrode. The heat-resistant layer is arranged in a region where at least the positive electrode active material layer and the negative electrode active material layer face each other, and has a melting point or decomposition temperature higher than the melting point or decomposition temperature of the separator. The electrolyte salt of the electrolyte solution contains at least one of the first, second, third, and fourth imid anions as an imid anion, thus providing excellent battery characteristics. Furthermore, the effects of this technology are not necessarily limited to those described herein, but may include any of the series of effects related to this technology described later. This is a perspective view showing the configuration of a secondary battery in one embodiment of this technology.This is a cross-sectional view showing a part of the configuration of the battery element shown in Figure 1.This is a cross-sectional view showing the overall configuration of the battery element shown in Figure 1.This is a cross-sectional view showing the configuration of the battery element in modified example 1.This is a cross-sectional view showing the configuration of the battery element in modified example 2.This is a cross-sectional view showing the configuration of the battery element in modified example 3.This is a cross-sectional view showing the configuration of the battery element in modified example 4.This is a cross-sectional view showing the configuration of the battery element