Vacuum drying method of large square lithium battery pole group

A technology for vacuum drying and lithium batteries, applied in battery electrodes, electrode manufacturing, electrode heat treatment, etc., can solve problems such as poor battery short circuit, limited baking efficiency, and unsatisfactory baking effect

Pending Publication Date: 2021-01-29
DONG GUAN LONGTTECH COMPANY LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The higher the temperature, the faster the water evaporation rate and the higher the baking efficiency. However, if the temperature is too high, the diaphragm in the lithium battery will shrink due to heat, resulting in a short circuit of the battery. Therefore, conventional vacuum baking must control the baking temperature within 85±3°C , the baking effect is not ideal
Increasing the vacuum can reduce the boiling point of water, increase the vaporization rate of water, and improve the baking efficiency, but the vacuum degree of conventional baking is only controlled below -85Kpa, and the effect of improving baking efficiency is limited

Method used

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  • Vacuum drying method of large square lithium battery pole group

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] In this embodiment, a vacuum drying method for a large square lithium battery electrode assembly is provided, comprising the following steps:

[0026] The unassembled positive electrode sheet and negative electrode sheet are vacuum-dried for the first time, and the water surface content of the positive electrode sheet and negative electrode sheet is detected. The temperature of the first vacuum drying is 150 ° C, and the vacuum degree of the first vacuum drying is - 0.090mpa;

[0027] Assemble the square cell in the order of the positive electrode sheet, separator, and negative electrode sheet in sequence. After the liquid is injected, the cell is vacuum-dried for the second time. The temperature of the first vacuum drying is 85°C. Vacuum degree of vacuum drying -0.090mpa;

[0028] The second vacuum drying is divided into two stages, a stage constant vacuum drying, and a variable vacuum drying stage based on the constant vacuum drying, and the variable vacuum degree dr...

Embodiment 2

[0032] In this embodiment, a vacuum drying method for a large square lithium battery electrode assembly is provided, comprising the following steps:

[0033] Based on embodiment 1, further shorten the time of vacuum drying for the first time, concrete steps are as follows:

[0034] The unassembled positive electrode sheet and negative electrode sheet are vacuum-dried for the first time, and the water content on the surface of the positive electrode sheet and negative electrode sheet is detected. The temperature of the first vacuum drying is 150 ° C, and the vacuum degree of the first vacuum drying is - 0.090mpa;

[0035] Assemble the square cell in the order of the positive electrode sheet, separator, and negative electrode sheet in sequence. After the liquid is injected, the cell is vacuum-dried for the second time. The temperature of the first vacuum drying is 85°C. The vacuum degree of vacuum drying is not higher than -0.085mpa. ;

[0036] The second vacuum drying is div...

Embodiment 3

[0039] In this embodiment, a vacuum drying method for a large square lithium battery electrode assembly is provided, comprising the following steps:

[0040] Based on embodiment 2, further shorten the time of vacuum drying for the first time, concrete steps are as follows:

[0041] The unassembled positive and negative plates were vacuum dried for the first time, and the water surface content of the positive and negative plates was detected. The temperature of the first vacuum drying was 180°C, and the vacuum degree of the first vacuum drying was - 0.100mpa;

[0042] Assemble the square cell in the order of the positive electrode sheet, the separator, and the negative electrode sheet in sequence. After the liquid is injected, the cell is vacuum-dried for the second time. The temperature of the first vacuum drying is 84.7°C. The vacuum degree of vacuum drying is -0.084mpa.

[0043] The second vacuum drying is divided into two stages, a stage constant vacuum drying, and a vari...

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Abstract

The invention discloses a vacuum drying method of a large square lithium battery pole group, and the method comprises the following steps: carrying out primary vacuum drying on unassembled positive plate and negative plate, and detecting the water content on the surfaces of the positive plate and the negative plate; sequentially assembling the square battery cell according to the sequence of the positive plate, the diaphragm and the negative plate, injecting liquid, and performing secondary vacuum drying on the battery cell, wherein the second vacuum drying is divided into two stages, one stage is constant vacuum drying, the other stage is variable vacuum drying based on the constant vacuum drying, and the variable vacuum drying stage is realized by introducing inert gas into drying equipment; and presetting a first vacuum task drying value and a second vacuum task drying value, wherein a first vacuum drying task value is larger than a second vacuum drying task value, the second vacuumdrying time can be controlled by setting the second vacuum drying task value, and then the whole vacuum drying time is controlled.

Description

technical field [0001] The present application relates to the technical field of lithium batteries, in particular to a vacuum drying method for a large square lithium battery electrode group. Background technique [0002] The three key factors in the lithium battery manufacturing process are moisture, dust, and aging; among them, moisture control in the lithium battery manufacturing process is particularly important. Moisture can easily lead to increased battery internal resistance, low capacity, poor cycle performance, and poor electrical performance, directly affecting battery performance. play. The baking process before the electrode group liquid injection is a key process to control the battery moisture. Research on how to improve the baking efficiency and reduce the electrode group moisture has become a problem that lithium battery manufacturers pay close attention to. [0003] At present, lithium battery manufacturers generally use a vacuum oven to bake the electrode ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/139H01M10/058
CPCH01M4/0471H01M4/139H01M10/058Y02E60/10Y02P70/50
Inventor 吴应强凌海生
Owner DONG GUAN LONGTTECH COMPANY LTD
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