Electrolyte for improving low temperature performance of lithium ion battery and lithium ion battery comprising same

A lithium-ion battery, low-temperature performance technology, applied in the direction of secondary batteries, circuits, electrical components, etc., can solve the problems of abnormal use of products, increased electrolyte viscosity, low charge and discharge capacity, etc., to improve reversible capacity performance, Effect of reducing concentration polarization and reducing interfacial impedance

CN109860709AActive Publication Date: 2019-06-07SHANSHAN ADVANCED MATERIALS QUZHOU CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2019-06-07

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Abstract

The invention discloses an electrolyte for improving the low temperature performance of a lithium ion battery and a lithium ion battery comprising the same. The electrolyte comprises conductive lithium salt, a non-aqueous organic solvent, and additives, wherein the additives include a conventional negative electrode film forming additive, an additive with the structure of Formula I, and an anhydride-type compound additive with the structure of Formula II. According to the battery electrolyte provided by the invention, under synergistic effects among the additive with the structure of Formula I, the anhydride-type compound additive with the structure of Formula II, a nitrogen-containing lithium salt type additive and the conventional negative electrode film forming additive, the electrolytethus has excellent film forming performance on the electrode surface, the cycle performance and the rate performance of the lithium ion battery in a low temperature condition can be effectively improved, and the high temperature cycle performance and the storage performance of the battery are little affected.
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Description

technical field

[0001] The invention relates to the field of lithium ion batteries, in particular to an electrolyte solution for improving the low-temperature performance of the lithium ion battery and a lithium ion battery containing the electrolyte solution. Background technique

[0002] The rapid development of electronic information technology and consumer electronics poses new challenges to the performance requirements of batteries, especially the low-temperature discharge performance of batteries. Key technical difficulties encountered. Therefore, developing a battery with low temperature resistance has become a major challenge and research hotspot in the field of lithium-ion batteries.

[0003] At present, the performance of the low-temperature electrolyte of lithium-ion batteries is mainly limited by three aspects: first, the viscosity of the commonly used EC-based electrolyte increases or even solidifies at low temperature, which makes the ionic conductivity of the...

Examples

Embodiment 1

[0049] Electrolyte preparation: In a glove box filled with argon, ethylene carbonate, dimethyl carbonate, propylene carbonate and methyl acetate were prepared according to the mass ratio of EC:DMC:PC:MA=3:3:3:2 Mixed, and then slowly added 12.5wt% lithium hexafluorophosphate based on the total weight of the electrolyte, 0.5wt% lithium bisfluorosulfonimide (LiTFSI) based on the total weight of the electrolyte and 2.5wt% based on the total weight of the electrolyte Lithium bisfluorosulfonyl imide (LiFSI), finally add 11.0wt% of the compound having the structure shown in formula I based on the total weight of the electrolyte, 0.1wt% of the cyclic acid anhydride compound shown in formula II, 2.0wt% sulfuric acid Vinyl ester (DTD) and 1.0wt% fluoroethylene carbonate (FEC) were stirred evenly to obtain the lithium-ion battery electrolyte of Example 1.

[0050] Preparation of soft-pack battery: stack the prepared positive electrode sheet, separator, and negative electrode sheet in or...

Embodiment 2-9

[0052] Embodiment 2-9 and comparative example 1-6

[0053] In Examples 2-9 and Comparative Examples 1-6, except that the proportions of the components of the electrolyte are added as shown in Table 2, the others are the same as in Example 1.

[0054] Table 2 Embodiment 1-9 and the composition ratio of each component of the electrolyte of comparative example 1-6

[0055]

[0056]

[0057] Performance Testing

[0058] Relevant performance tests were carried out on the batteries and their electrolytes prepared in Examples 1-9 and Comparative Examples 1-6.

[0059] (1) Electrolyte conductivity and viscosity test: Use conductivity meter and viscosity tester to measure the ion conductivity and viscosity of the electrolyte at different temperatures.

[0060] (2) Test of capacity remaining rate after high temperature storage at 45°C: first place the battery at room temperature and cycle charge and discharge once at 0.5C (4.2V~3.0V), record the discharge capacity C of the batte...