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Formation method for prolonging storage time of lithium ion battery

A technology of lithium-ion batteries and formation methods, which is applied in the field of formation of lithium-ion batteries to improve storage time, can solve problems such as battery deterioration, lithium dissolution, battery over-discharge, etc., to maintain rate performance, avoid internal resistance increase, and reduce self-discharge. The effect of discharge efficiency

Active Publication Date: 2019-05-21
HANGZHOU DOLAY ELECTRONICS TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Lithium iron phosphate has the characteristics of safety, long cycle life, low toxicity and low cost, and has become one of the research targets of power lithium-ion batteries. However, after long-term storage of batteries of this material, the situation of battery overdischarge due to self-discharge is more obvious. , and over-discharge will cause lithium to dissolve on the surface of the positive electrode, resulting in battery deterioration

Method used

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  • Formation method for prolonging storage time of lithium ion battery
  • Formation method for prolonging storage time of lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] According to the proportion of the total mass of the electrolyte, FEC accounts for 0.5% of the electrolyte, and NaF is 0.005%, which includes the following steps:

[0031] 1), the lithium-ion battery after liquid injection was left to stand for 6 hours;

[0032] 2), constant current charging to 3.9V, the current size is 0.02C;

[0033] 3), let stand for 1h;

[0034] 4) Charge with a constant voltage of 3.9V until the charging current drops below 0.01C;

[0035] 5), constant current discharge to 3.1V, the current size is 0.1C;

[0036] 6), at 3.08-3.12V, carry out 5 times of small current charge and discharge cycle, the small current is 0.005C;

[0037] 7) Charge the battery with a constant current of 0.02C to the 3.9V;

[0038] 8), at 3.88-3.92V, carry out 5 small current charge and discharge cycles, and the small current is 0.005C;

[0039] 9) Charge at a constant current of 0.02C to 4.2V, and then charge at a constant voltage at this voltage until the charging cu...

Embodiment 2

[0042] According to the ratio of the total mass of the electrolyte, FEC accounts for 1.5% of the electrolyte, and NaF is 0.02%, which includes the following steps:

[0043] 1), the lithium-ion battery after liquid injection was left to stand for 6 hours;

[0044] 2), constant current charging to 4.0V, the current size is 0.04C;

[0045] 3), let stand for 6 hours;

[0046] 4) Charge at a constant voltage of 4.0V until the charging current drops below 0.01C;

[0047] 5), constant current discharge to 3.2V, the current size is 0.2C;

[0048] 6), at 3.18-3.22V, carry out 5 times of small current charge and discharge cycles, the small current is 0.01C;

[0049] 7) Charge the battery to the 4.0V with a constant current of 0.02-0.04C;

[0050] 8), at 3.98-4.02V, carry out a small current charge and discharge cycle for 5 times, and the small current is 0.01C;

[0051] 9) Charge at a constant current of 0.04C to 4.3V, and then charge at a constant voltage at this voltage until the...

Embodiment 3

[0054] According to the ratio of the total mass of the electrolyte, FEC accounts for 1% of the electrolyte, and NaF is 0.01%, which includes the following steps:

[0055] 1), the lithium-ion battery after liquid injection was left to stand for 8 hours;

[0056] 2), constant current charging to 3.9V, the current size is 0.02C;

[0057] 3), let stand for 6 hours;

[0058] 4) Charge with a constant voltage of 3.9V until the charging current drops below 0.01C;

[0059] 5), constant current discharge to 3.1V, the current size is 0.1C;

[0060] 6), at 3.08-3.12V, carry out 10 cycles of charging and discharging with a small current, and the small current is 0.005C;

[0061] 7) Charge the battery with a constant current of 0.02C to the 3.9V;

[0062] 8), at 3.88-3.92V, carry out 10 cycles of charging and discharging with a small current, and the small current is 0.005C;

[0063] 9) Charge at a constant current of 0.02C to 4.2V, and then charge at a constant voltage at this voltag...

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Abstract

The invention provides a formation method for prolonging storage time of a lithium ion battery. A positive active material in the lithium ion battery is mainly composed of lithium iron phosphate; an electrolyte of the lithium ion battery comprises an additive composed of fluoroethylene carbonate (FEC) and NaF, wherein the FEC accounts for 0.5-1.5% of the electrolyte and the NAF accounts for 0.001-0.02% of the electrolyte according to the total mass ratio of the electrolyte. According to the formation method, a current, a voltage and formation time are controlled to form a stable SEI film, so that the battery performance deterioration caused by over-discharge due to self-discharge in a storage process of the battery is avoided.

Description

technical field [0001] The invention relates to the technical field of flexible packaging lithium-ion batteries, in particular to a formation method for improving the storage time of lithium-ion batteries. Background technique [0002] Lithium-ion batteries, as a means of making batteries lightweight and high-energy, will occupy a relatively high proportion of the incremental market. The new policy of new energy vehicles has released a signal to promote battery performance and increase energy density. With the continuous improvement of the subsidy threshold, lithium-ion batteries can help more battery companies improve energy density and product competitiveness. Lithium iron phosphate has the characteristics of safety, long cycle life, low toxicity and low cost, and has become one of the research targets of power lithium-ion batteries. However, after long-term storage of batteries of this material, the situation of battery overdischarge due to self-discharge is more obvious...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/44H01M10/0567H01M10/058
CPCY02E60/10Y02P70/50
Inventor 曹怡珺
Owner HANGZHOU DOLAY ELECTRONICS TECH
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