Lithium ion secondary battery and production method thereof

Patent metadata

Field	Value
Publication number	US-12347866-B2
Application number	US-202117447228-A
Country	US
Kind code	B2
Filing date	Sep 9, 2021
Priority date	Sep 17, 2020
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

A lithium ion secondary battery includes: a positive electrode having a positive electrode active material layer on a surface of a positive electrode collector; a negative electrode a having a negative electrode active material layer on a surface of a negative electrode collector; and a nonaqueous electrolyte. The positive electrode, the negative electrode, and the nonaqueous electrolyte are accommodated in a battery case. The nonaqueous electrolyte contains γ-butyrolactone as a main component of a nonaqueous solvent. A monoalkyl sulfate ion-derived coat is formed on the surface of the positive electrode active material layer. A VC-derived coat is formed on the surface of the negative electrode active material layer.

First claim

The invention claimed is:

1. A lithium ion secondary battery comprising: a positive electrode having a positive electrode active material layer on a surface of a positive electrode collector; a negative electrode having a negative electrode active material layer on a surface of a negative electrode collector; a nonaqueous electrolyte, the positive electrode, the negative electrode, and the nonaqueous electrolyte being accommodated in a battery case,
the nonaqueous electrolyte containing γ-butyrolactone as a main component of a nonaqueous solvent;
a coat containing a component derived from vinylene carbonate on a surface of the negative electrode active material layer; and
a coat containing a component derived from monoalkyl sulfate ions on a surface of the positive electrode active material layer, wherein
the coat formed on the surface of the positive electrode active material layer further contains a component derived from bis(oxalate)borate ions,
one surface of the coat formed on the surface of the negative electrode active material layer directly contacts the surface of the negative electrode active material layer, whereas the other surface of the coat formed on the surface of the negative electrode active material layer directly contacts the nonaqueous electrolyte, and
one surface of the coat formed on the surface of the positive electrode active material layer directly contacts the surface of the positive electrode active material layer, whereas the other surface of the coat formed on the surface of the positive electrode active material layer directly contacts the nonaqueous electrolyte.

2. The lithium ion secondary battery of claim 1 , wherein
the coat formed on the surface of the negative electrode active material layer further contains a component derived from the monoalkyl sulfate ions.

3. The lithium ion secondary battery of claim 1 , wherein
the positive electrode contains lithium iron phosphate having an olivine crystal structure as a positive electrode active material.

4. The lithium ion secondary battery of claim 1 , wherein
the negative electrode contains a carbon material as a negative electrode active material.

5. The lithium ion secondary battery of claim 1 , wherein
the nonaqueous electrolyte contains, as the nonaqueous solvent, dibutyl carbonate in addition to the γ-butyrolactone.

6. The lithium ion secondary battery of claim 1 , wherein
both of the coat formed on the surface of the negative electrode active material layer and the coat formed on the surface of the positive electrode active material layer are formed by an initial charge process.

7. The lithium ion secondary battery of claim 6 , wherein
the initial charge is performed such that an electric potential of the negative electrode is equal to or below a reduction potential of the vinylene carbonate.

8. The lithium ion secondary battery of claim 7 , wherein
the concentration of the vinylene carbonate in the nonaqueous electrolyte before the initial charge process is 0.3 mass % or more to 3 mass % or less.

9. The lithium ion secondary battery of claim 7 , wherein
the concentration of the lithium monoalkyl sulfate in the nonaqueous electrolyte before the initial charge process is 0.3 mass % or more to 1.5 mass % or less.

10. The lithium ion secondary battery of claim 7 , wherein
the concentration of the lithium bis(oxalate)borate in the nonaqueous electrolyte before the initial charge process is 0.3 mass % or more to 1.5 mass % or less.

11. The lithium ion secondary battery of claim 8 , wherein
the concentration of the vinylene carbonate in the nonaqueous electrolyte before the initial charge process is 0.5 mass % or more to 2.5 mass % or less.

12. The lithium ion secondary battery of claim 11 , wherein
the concentration of the vinylene carbonate in the nonaqueous electrolyte before the initial charge process is 1 mass % or more to 2 mass % or less.

13. The lithium ion secondary battery of claim 9 , wherein
the concentration of the lithium monoalkyl sulfate in the nonaqueous electrolyte before the initial charge process is 0.5 mass % or more to 1 mass % or less.

14. The lithium ion secondary battery of claim 10 , wherein
the concentration of the lithium bis(oxalate)borate in the nonaqueous electrolyte before the initial charge process is 0.5 mass % or more to 1 mass % or less.

Assignees

• Mazda Motor

Inventors

• Shimamoto Kei
• Fukunaga Takao
• Sugiyama Hideyuki
• Masuda Wataru
• Fujita Hiroki
• Higuchi munetaka

Classifications

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0587

  of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators · CPC title

• H01M10/0569

  characterised by the solvents · CPC title