-70 DEG C lithium ion battery low-temperature electrolyte and preparation method thereof

A lithium-ion battery, electrolyte technology, applied in secondary batteries, circuits, electrical components, etc., can solve the problems of low oxidative SEI instability of electrolyte, sacrificing battery energy density, power density and safety, etc. Affordable price, easy to implement, guaranteed stable effect

Active Publication Date: 2022-04-12
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this will sacrifice the energy density, power density, and safety of the battery, because the lithium battery will be subjected to high pressure of several kilopascals, low oxidation defects in the electrolyte, and SEI instability

Method used

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  • -70 DEG C lithium ion battery low-temperature electrolyte and preparation method thereof
  • -70 DEG C lithium ion battery low-temperature electrolyte and preparation method thereof
  • -70 DEG C lithium ion battery low-temperature electrolyte and preparation method thereof

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Embodiment 1

[0039] The electrolytic solution of the present embodiment comprises commercial lithium salt and solvent, and commercial lithium salt is the lithium difluorooxalate borate (LiDFOB) that molecular weight is 143.77, and solvent is made up of fluoroethylene carbonate, dimethyl sulfite and isobutyl formate, The volume percentage of fluoroethylene carbonate in the solvent is 20vt%, the volume percentage of dimethyl sulfite is 20vt%, and the volume percentage of isobutyl formate is 60vt%.

[0040] The electrolyte preparation method of the present embodiment is as follows:

[0041] Step 1. Put the commercial lithium salt into the vacuum transition chamber of the glove box. The temperature of the transition chamber is set at 70-90°C, and the drying time is 3-5 days to ensure that the moisture content detected by the moisture detector is lower than 100ppm.

[0042] Step 2, transferring the dried lithium salt obtained in step 1 to a glove box.

[0043] Step 3, will Molecular sieves w...

Embodiment 2

[0047]The difference between this embodiment and Example 1 is: the volume percentage of fluoroethylene carbonate in the solvent is 20vt%, the volume percentage of dimethyl sulfite is 35vt%, the volume percentage of isobutyl formate is 45vt%, and all the other operations The process and parameter settings are the same as in Example 1, and the obtained electrolyte is referred to as 45vt% IF electrolyte for short.

Embodiment 3

[0049] The difference between this embodiment and Example 1 is: the volume percentage of fluoroethylene carbonate in the solvent is 20vt%, the volume percentage of dimethyl sulfite is 40vt%, the volume percentage of isobutyl formate is 40vt%, and all the other operations The process and parameter setting are the same as in Example 1.

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Abstract

The invention discloses-70 DEG C lithium ion battery low-temperature electrolyte and a preparation method thereof, and belongs to the technical field of lithium ion battery electrolyte. According to the invention, wide-temperature-range lithium salt lithium difluoro (oxalato) borate is used as a lithium ion donor, fluoroethylene carbonate which has high-pressure oxidation resistance and is beneficial to a negative electrode film-forming agent and a dimethyl sulfite cosolvent which forms effective coordination with lithium ions are added, and an isobutyl formate cosolvent with high adsorption performance is combined; the low-temperature electrolyte with low freezing point, low viscosity and high lithium ion conductivity is obtained, transmission and diffusion of lithium ions at low temperature are effectively improved, a stable SEI interface is constructed, formation of lithium dendrites is inhibited, and the low-temperature electrolyte can stably and safely operate at the temperature of 70 DEG C below zero.

Description

technical field [0001] The invention relates to a -70°C lithium-ion battery low-temperature electrolyte and a preparation method thereof, belonging to the technical field of lithium-ion battery electrolytes. Background technique [0002] As a new generation of high-energy power supply, lithium-ion batteries are widely used in various fields such as military industry, electronic equipment, power tools, and electric vehicles. However, the practical application of lithium-ion batteries is plagued by safety concerns, as well as catastrophic capacity fading at subzero temperatures. The operating temperature of commercial lithium-ion batteries with carbonate-based electrolytes is usually limited to −20 °C–50 °C because uncontrollable side reactions can occur outside this temperature range, which can lead to severe energy loss. Unlike carbonate electrolytes, ether-based electrolytes exhibit better low-temperature performance due to their lower melting points and are compatible wit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0569H01M10/0568H01M10/0525
CPCY02E60/10
Inventor 何伟东刘继鹏韩杰才刘远鹏杨春晖董运发
Owner HARBIN INST OF TECH
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