Non-aqueous electrolyte and Li-ion secondary battery, and method for producing them

A non-aqueous electrolyte, electrolyte technology, applied in the direction of non-aqueous electrolyte storage battery, electrolyte storage battery manufacturing, secondary battery, etc., can solve problems affecting battery performance, achieve good high-temperature storage performance, increase discharge capacity at room temperature, preparation method simple effect

Inactive Publication Date: 2008-07-02
BYD CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above method will introduce metal ion impurities into the electrolyte duri

Method used

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  • Non-aqueous electrolyte and Li-ion secondary battery, and method for producing them

Examples

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Example Embodiment

[0018] The preparation method of the electrolyte of the present invention is a conventionally used method. It is only necessary to dissolve the lithium salt and the weak acid salt of lithium in an organic solvent. The concentration of the lithium salt as an electrolyte is 0.5-2.0 mol / liter, preferably 0.5-1.5 mol / liter. Based on the total amount of the non-aqueous electrolyte, the content of the weak acid salt of lithium is 0.001 to 5% by weight, preferably 0.005 to 3% by weight.

[0019] Preferably, the weak acid salt of lithium is pre-baked at 120-180° C. for 5-24 hours before being mixed with the electrolyte, so that the water content of the weak acid salt of lithium is below 30 ppm. In order to sufficiently and efficiently remove the very small amount of moisture in the weak acid salt of lithium, the baking is preferably performed in a vacuum oven, and the vacuum pressure of the vacuum oven is less than atmospheric pressure.

[0020] The lithium ion secondary battery of the pr...

Example Embodiment

[0036] Example 1

[0037] This example illustrates the non-aqueous electrolyte provided by the present invention and its preparation method.

[0038] Mix 100 ml of ethylene carbonate, 100 ml of diethyl carbonate and 100 ml of ethyl methyl carbonate, and add 45.573 g of LiPF as electrolyte lithium salt 6 , Stir evenly to obtain a mixed solution with an electrolyte lithium salt concentration of 1.0 mol / L, and then add 3.756 g of lithium acetate as a weak acid salt of lithium, based on the total amount of the electrolyte, the content of the weak acid salt of lithium It is 1.0% by weight, and the mixture is evenly stirred to obtain electrolyte A1.

Example Embodiment

[0041] Example 2

[0042] The electrolyte was prepared according to the method of Example 1. The difference was that the weak acid salt of lithium was lithium benzoate, and the amount was 11.267 grams. Based on the total amount of the electrolyte, the weak acid salt of lithium was The content was 3.0% by weight, and electrolyte A2 was obtained.

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Abstract

The invention relates to a non-aqueous electrolyte which contains lithium salt and organic solvent which are taken as electrolyte, wherein, the electrolyte also contains weak acid salt of lithium. By adding the weak acid salt of lithium into the non-aqueous electrolyte, the invention can remarkably reduce the content of free acid in the electrolyte and can control the content of the free acid in the electrolyte within 30 ppm. Besides, hydrofluoric acid is unlikely to repeatedly generated due to water entering even when the invention is stored for a long time. In addition, a cell manufactured by adopting the electrolyte provided by the invention has good cycle performance and high-temperature storage performance. The invention also presents improved discharge performance of large current and discharge capacity under normal temperature.

Description

technical field [0001] The invention relates to an electrolytic solution, a battery containing the electrolytic solution and a preparation method thereof, in particular to a non-aqueous electrolytic solution, a lithium ion secondary battery containing the electrolytic solution and a preparation method thereof. Background technique [0002] Lithium-ion batteries have developed rapidly in the past two decades. As a new energy source, lithium-ion battery is characterized by its high voltage, high capacity, low consumption, no memory effect, no pollution, small size, high specific energy, small internal resistance, low self-discharge rate, many cycles, safe, reliable and Due to the advantages of arbitrary change in volume and appearance, it stands out from many batteries and has attracted more and more attention. It has been widely used in electronic information products such as notebook computers and mobile phones. [0003] As an important part of lithium-ion secondary batteri...

Claims

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Application Information

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IPC IPC(8): H01M10/02H01M10/40H01M10/38H01M10/0525H01M10/056H01M10/058
CPCY02E60/122Y02E60/10Y02P70/50
Inventor 刘海英周贵树
Owner BYD CO LTD
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