Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using same

A non-aqueous electrolyte, secondary battery technology, applied in non-aqueous electrolyte storage batteries, secondary batteries, battery electrodes, etc., can solve the problem of increased battery gas generation, non-aqueous electrolyte difficult to penetrate the electrode plate, easy to be oxidized and decomposed, etc. problem, to achieve the effect of excellent low temperature characteristics, excellent storage characteristics, and excellent charge-discharge cycle characteristics

Inactive Publication Date: 2011-04-20
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the viscosity of the non-aqueous electrolyte is high, it is not only difficult for the non-aqueous electrolyte to penetrate the plate, but also the ion conductivity decreases
Therefore, a reduction in rate characteristics at low temperatures is particularly likely to occur
[0009] In addition, although VC forms a covering film on the negative electrode, it is easily oxidized and decomposed on the positive electrode.
Therefore, in the battery of Patent Document 3, especially in the positive electrode, the amount of gas generated due to the oxidative decomposition of VC increases.

Method used

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  • Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using same
  • Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using same
  • Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] (a) Preparation of negative electrode

[0100] Process (i)

[0101] First, carboxymethylcellulose (hereinafter referred to as CMC, molecular weight: 400,000), which is a water-soluble polymer, was dissolved in water to obtain an aqueous solution having a CMC concentration of 1.0% by weight. Mix 100 parts by weight of natural graphite particles (the average particle diameter is 20 μm, the average circularity is 0.92, and the specific surface area is 4.2m 2 / g) and 100 parts by weight of the CMC aqueous solution, while controlling the temperature of the mixture to 25°C, it was stirred. Thereafter, the mixture was dried at 120° C. for 5 hours to obtain a dry mixture. In the dry mixture, the amount of CMC was 1.0 parts by weight per 100 parts by weight of graphite particles.

[0102] Process (ii)

[0103] 101 parts by weight of the obtained dry mixture, 0.6 parts by weight, 0.9 parts by weight of a particle-shaped, styrene unit and butadiene unit-containing, rubber-elas...

Embodiment 2

[0131] In addition to using W EC :W PC :W DEC A nonaqueous electrolyte was prepared in the same manner as in Example 1 except that it was changed as in Table 1. Batteries 2 to 18 were produced in the same manner as in Example 1 except that the obtained nonaqueous electrolyte was used. In addition, Batteries 2, 3, 9, 10, and 15 to 18 are all batteries of comparative examples.

[0132] Batteries 2 to 18 were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0133] Table 1

[0134]

[0135] It can be seen from Table 1 that for the weight ratio W of PC PC 30-60% by weight, W C / W SLThe battery with a non-aqueous electrolyte of 1.0 has good cycle capacity retention rate and low-temperature discharge capacity retention rate. Furthermore, it can be seen that the battery after the cycle has little swelling and the amount of gas generated is also small. Furthermore, for the weight ratio W using PC PC and the weight ratio of EC W EC Ratio: ...

Embodiment 3

[0141] The total amount except additives is set to 3.0% by weight, so that W C / W SL A nonaqueous electrolyte was prepared in the same manner as in Example 1 except that it was changed as in Table 2. Batteries 19 to 29 were fabricated in the same manner as in Example 1 except that the obtained nonaqueous electrolyte was used. In addition, batteries 19 to 22 and battery 29 are batteries of comparative examples.

[0142] Batteries 19 to 29 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0143] Table 2

[0144]

[0145] As can be seen from Table 2, for the use of the weight ratio W of cyclic carbonate (VC) with C=C unsaturated bond C The weight ratio W with the sultone compound (PS) SL Ratio: W C / W SL Satisfy 0.5≤W C / W SL The non-aqueous electrolyte batteries with ≤3.0 have particularly good cycle capacity retention rate and low-temperature discharge capacity retention rate. In addition, the battery swells after cycling with ...

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Abstract

Disclosed is a nonaqueous electrolyte which is capable of satisfactorily suppressing gas generation in a nonaqueous electrolyte secondary battery when the battery is stored in a high temperature environment or during the charge/discharge cycles. The nonaqueous electrolyte contains a nonaqueous solvent and a solute dissolved in the nonaqueous solvent. The nonaqueous solvent contains ethylene carbonate, propylene carbonate, diethyl carbonate and an additive. The additive contains a sartone compound and a cyclic carbonate having a C=C unsaturated bond. The weight ratio of the propylene carbonate (WPC) in the total of the ethylene carbonate, propylene carbonate and diethyl carbonate is 30-60% by weight. The ratio of the weight ratio of the propylene carbonate (WPC) to the weight ratio of the ethylene carbonate (WEC) in the total of the ethylene carbonate, propylene carbonate and diethyl carbonate, namely WPC/WEC satisfies the following relation: 2.25 <= WPC/WEC <= 6. The weight ratio of the cyclic carbonate having a C=C unsaturated bond (WC) to the weight ratio of the sartone compound (WSL), namely WC/WSL satisfies the following relation: 0.5 <= WC/WSL <= 3.

Description

technical field [0001] The present invention relates to non-aqueous electrolyte and non-aqueous electrolyte secondary battery, especially relates to the composition of non-aqueous electrolyte. Background technique [0002] The nonaqueous electrolyte of the nonaqueous electrolyte secondary battery typified by the lithium ion secondary battery contains a nonaqueous solvent and a solute dissolved in the nonaqueous solvent. As the solute, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 )Wait. [0003] Non-aqueous solvents include chain carbonates and cyclic carbonates. As a chain carbonate, diethyl carbonate (DEC) etc. are mentioned, for example. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC). In addition, generally, non-aqueous solvents containing cyclic carboxylate, chain ether, cyclic ether and the like can also be used. [0004] Patent Document 1 discloses a nonaqueous electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0569H01M4/133H01M4/36H01M4/505H01M4/525H01M4/587H01M10/0525H01M10/0567
CPCH01M4/587H01M10/0569H01M4/133H01M10/0567H01M4/505H01M10/052Y02E60/122H01M4/525Y02E60/10Y02P70/50
Inventor 出口正树笠松真治
Owner PANASONIC CORP
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