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A kind of static method of liquid injection for power battery

A power battery and standing technology, which is applied in the manufacture of battery pack components, non-aqueous electrolyte batteries, electrolyte batteries, etc., can solve the problems of damaging the SEI film, increasing the internal resistance of the battery, and deteriorating battery performance, so as to improve the electrical performance and safety performance, reduce the degree of polarization, and reduce the effect of adverse effects

Active Publication Date: 2015-12-09
BEIQI FOTON MOTOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the infiltration effect of positive and negative electrode sheets, positive and negative electrode materials, battery separator and electro-liquid after liquid injection of lithium-ion batteries directly affects the formation of battery SEI film, thereby affecting the electrochemical performance of the battery.
[0004] At present, the lithium iron phosphate battery is used to leave the opening in dry air for a period of time after the liquid injection is completed. The time is usually dozens of hours. The liquid hole is in contact with the air for a long time, and the moisture in the air is absorbed into the electrolyte inside the battery. The moisture will cause the electrolyte salt in the electrolyte to decompose and produce hydrogen fluoride (HF), which will react with the positive and negative materials of the battery plate and damage the subsequent The SEI film formed during activation deteriorates battery performance and impairs battery life
At the same time, the conventional method of standing still for a period of time after the battery is filled with liquid cannot guarantee the full infiltration of the battery positive pole material, battery pole piece, battery separator and electro-hydraulic, and the battery needs a long time to stand still. , and the infiltration effect of this natural state cannot guarantee the consistency of the battery’s electro-hydraulic infiltration. Chemicalization and concentration polarization increase. During the charging and discharging process of the battery, the electro-hydraulic and the positive and negative electrode materials have side reactions to generate gas, which cannot form a stable SEI film. At the same time, it will also cause battery swelling and damage the structure of the battery’s positive and negative electrode materials. Deterioration of battery performance during subsequent use, resulting in rapid increase of battery internal resistance, rapid shortening of cycle life, and poor battery consistency are important factors, as well as important factors affecting the safety of power batteries

Method used

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  • A kind of static method of liquid injection for power battery
  • A kind of static method of liquid injection for power battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] In this embodiment, the battery cell is left to stand after liquid injection according to the following steps.

[0048] S1, inject liquid into the power battery after assembly, and the liquid injection volume is 60% of the total liquid injection volume;

[0049] S2, putting the battery after liquid injection into a static box with temperature control and vacuum control and pressurization;

[0050] S3, adjust the temperature of the static box, and adjust the temperature to 40°C;

[0051] S4, vacuumize the static battery for the first time, the vacuum degree is -30KPa, and the static time is 1h;

[0052] S5, when the first vacuum resting time is up, pressurize the battery with nitrogen gas for the first time, keep the pressure in the box at 40KPa, and let the resting time be 1h;

[0053] S6, after the first pressurization and resting time is up, the battery is vacuumed for the second time, the vacuum degree is controlled at -50Kpa, and the resting time is 1h;

[0054] ...

Embodiment 2

[0059] In this embodiment, the battery cell is left to stand after liquid injection according to the following steps.

[0060] S1, inject liquid into the power battery after assembly, and the liquid injection volume is 70% of the total liquid injection volume;

[0061] S2, putting the battery after liquid injection into a static box with temperature control and vacuum control and pressurization;

[0062] S3, adjust the temperature of the static box, and adjust the temperature to 50°C;

[0063] S4, vacuumize the static power battery for the first time, the vacuum degree is -35KPa, and the static time is 1.5h;

[0064] S5, when the vacuum standing time in the first step is up, pressurize the battery with nitrogen for the first time, keep the pressure in the box at 45KPa, and keep it for 1.5h;

[0065] S6, after the first pressurization and resting time is up, vacuumize the battery for the second time, and control the vacuum degree to -55Kpa, and the resting time is 1-2h;

[0...

Embodiment 3

[0071] In this embodiment, the battery cell is left to stand after liquid injection according to the following steps.

[0072] S1, inject liquid into the power battery after assembly, and the liquid injection volume is 80% of the total liquid injection volume;

[0073] S2, putting the battery after liquid injection into a static box with temperature control and vacuum control and pressurization;

[0074] S3, adjust the temperature of the static box, and adjust the temperature to 60°C;

[0075] S4, vacuumize the static power battery for the first time, the vacuum degree is -40KPa, and the static time is 2h;

[0076] S5, when the first vacuum resting time is up, pressurize the battery with nitrogen for the first time, keep the pressure in the box at 50KPa, and rest for 2 hours;

[0077] S6, after the first pressurization and resting time is up, the battery is vacuumed for the second time, the vacuum degree is controlled at -60Kpa, and the resting time is 2h;

[0078] S7, when...

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Abstract

The invention provides a liquid-injection standing method for a power cell, and the power cell is a lithium iron phosphate cell. The method comprises the following steps: injecting part of an electrolyte into the power cell, putting a constant-temperature standing box; performing three-time vacuumizing and three-time pressurization on the power cell, standing for a certain time after each vacuumizing and each pressurization; releasing the pressure of the power cell to a normal pressure, taking the power cell from the constant-temperature standing box, wherein the second vacuum degree is larger than the first vacuum degree and less than the third vacuum degree, and the second pressure is larger than the first pressure and less than the second pressure; and operating according to the subsequent operations. By employing the method, a stable compact solid electrolyte interfacial film is formed on the surfaces of the anode and cathode materials of the cell, the performances of the ferric phosphate lithium iron phosphate power cell are effectively improved, also the electrolyte loss is reduced, the work environment of the liquid injection operation is improved, and the method has the advantages of simple operation, safety and reliability.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a liquid injection and standing method for power batteries. Background technique [0002] Due to the characteristics of high voltage, high energy density, no memory effect, green and pollution-free, lithium-ion secondary power batteries have been widely used in electric tools and electric vehicles in recent years. [0003] In the production process of lithium-ion secondary power batteries, cell injection and standing still is a very important process operation. After the power battery is assembled, the battery is injected with electrolyte, and the battery is left to stand after the liquid injection, so that The electrolyte fully infiltrates the positive and negative electrode materials of the battery and the battery diaphragm, and acts as a lithium ion current transmission medium during the charging and discharging process of the battery. After the battery is injected ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/058
CPCH01M10/058H01M50/60Y02E60/10Y02P70/50
Inventor 曹远敏
Owner BEIQI FOTON MOTOR CO LTD