CN-115978915-B - Drying method and device for battery cells

CN115978915BCN 115978915 BCN115978915 BCN 115978915BCN-115978915-B

Abstract

The embodiment of the application provides a drying method and a device for an electric core, the method comprises measuring the moisture content of the electric core to be dried, judging the drying stage corresponding to the electric core to be dried according to the moisture content, executing the drying operation corresponding to the drying stage on the electric core to be dried, the application can effectively reduce the drying time of the electric core by drying in stages according to the moisture distribution in the electric core in the baking process, the method can prevent the whole battery cell from being damaged, achieves the aim of rapidly removing the moisture by adopting different technological means according to three stages of moisture distribution in the battery cell in the baking process, and ensures that the moisture content in the treated battery cell is lower than 80ppm and lower than the current standard, thereby not only effectively reducing the drying time of the battery cell, but also preventing the whole battery cell from being damaged.

Inventors

LI ZHENG
QIN QINGBO
FENG YUCHUAN
LI QINGHUI
WANG MINGHUI
HE HONGCAI

Assignees

宜春清陶能源科技有限公司

Dates

Publication Date: 20260505
Application Date: 20221014

Claims (9)

1. The method for drying the battery cell is characterized by comprising the following steps of: Measuring the moisture content of the electric core to be dried, judging a drying stage corresponding to the electric core to be dried according to the moisture content, and executing a drying operation corresponding to the drying stage on the electric core to be dried, wherein the drying stage corresponding to the electric core to be dried is a first stage when the moisture content is larger than a first threshold value, the drying stage corresponding to the electric core to be dried is a second stage when the moisture content is between the first threshold value and a second threshold value, the drying stage corresponding to the electric core to be dried is a third stage when the moisture content is lower than the second threshold value, and the drying operation corresponding to the first stage at least comprises: Heating a vacuum oven for processing the battery cells to be dried to a first temperature at a first heating rate under a first vacuum degree, and performing a second operation after a first period of time, wherein the second operation comprises the steps of introducing inert gas to the vacuum oven to be a second vacuum degree, vacuumizing the vacuum oven to the first vacuum degree, keeping the second period of time, and repeating the second operation until the moisture content in the battery cells to be dried is lower than the first threshold value; the drying operation corresponding to the second stage comprises the following steps: Repeating a third operation until the moisture content in the battery core to be dried is lower than the second threshold value, wherein the third operation comprises the steps of heating the vacuum oven to a second temperature at a second heating rate under the first vacuum degree, introducing inert gas into the vacuum oven to the second vacuum degree after baking for a third period of time, and vacuumizing the vacuum oven to a third vacuum degree, wherein the second temperature is higher than the first temperature, the third period of time is higher than the second period of time, the second threshold value is lower than the first threshold value, and the third vacuum degree is not lower than the first vacuum degree; the second ramp rate is greater than the first ramp rate.
2. The method of claim 1, wherein the drying operation corresponding to the third stage comprises: And repeating the fourth operation until the moisture content in the electric core to be dried meets the requirement, wherein the fourth operation comprises the steps of introducing inert gas into the vacuum oven until the pressure of the inert gas is a preset pressure value, and vacuumizing the vacuum oven to the first vacuum degree after maintaining the fourth time period.
3. The method of claim 2, wherein the first threshold is 400ppm and/or the second threshold is 180ppm.
4. The method according to any one of claims 1 to 3, wherein the first vacuum degree is 50 to 80pa, and/or the second vacuum degree is 85000 to 100000pa.
5. A method of drying a battery cell according to any one of claims 1 to 3, wherein the first temperature rise rate is 0.8-1.5 ℃ per minute, and/or the first temperature is 65-70 ℃.
6. The method according to claim 5, wherein the second temperature rise rate is 5-10 ℃ per minute, and/or the second temperature is 85-90 ℃.
7. The method according to claim 2, wherein the second time period is 3-10min, and/or the third time period is 30-45min, and/or the fourth time period is 5-10min.
8. The method of claim 2, wherein the predetermined pressure value is 0.2Mpa.
9. A drying device for an electrical core, the device comprising at least: The measuring module is used for measuring the moisture content of the battery cell to be dried; The vacuum oven is used for executing the drying operation corresponding to the drying stage on the electric core to be dried; The processing module is configured to determine a drying stage corresponding to the to-be-dried battery cell according to the moisture content, and control the vacuum oven to perform a drying operation corresponding to the drying stage on the to-be-dried battery cell, where the drying stage corresponding to the to-be-dried battery cell is a first stage when the moisture content is greater than a first threshold, the drying stage corresponding to the to-be-dried battery cell is a second stage when the moisture content is between the first threshold and a second threshold, and the drying stage corresponding to the to-be-dried battery cell is a third stage when the moisture content is lower than the second threshold, and the drying operation corresponding to the first stage at least includes: Heating a vacuum oven for processing the battery cells to be dried to a first temperature at a first heating rate under a first vacuum degree, and performing a second operation after a first period of time, wherein the second operation comprises the steps of introducing inert gas to the vacuum oven to be a second vacuum degree, vacuumizing the vacuum oven to the first vacuum degree, keeping the second period of time, and repeating the second operation until the moisture content in the battery cells to be dried is lower than the first threshold value; the drying operation corresponding to the second stage comprises the following steps: Repeating a third operation until the moisture content in the battery core to be dried is lower than the second threshold value, wherein the third operation comprises the steps of heating the vacuum oven to a second temperature at a second heating rate under the first vacuum degree, introducing inert gas into the vacuum oven to the second vacuum degree after baking for a third period of time, and vacuumizing the vacuum oven to a third vacuum degree, wherein the second temperature is higher than the first temperature, the third period of time is higher than the second period of time, the second threshold value is lower than the first threshold value, and the third vacuum degree is not lower than the first vacuum degree.

Description

Drying method and device for battery cells Technical Field The application relates to the technical field of battery manufacturing, in particular to a drying method and device for a battery cell. Background The water has a great influence on the performance of the battery, and in order to ensure the safety and the cycle performance of the battery, the battery is usually required to be subjected to water removal treatment after the battery is prepared by adopting a battery cell drying procedure in the battery cell production process. In the process of drying the battery cell, the inside of the battery cell (comprising the positive plate, the negative plate and the diaphragm) needs to be subjected to moisture removal treatment, the moisture content after drying is less than or equal to 150PPM, and the requirements are severe. The existing battery cell drying process generally needs tens to twenty hours to reach the drying requirement. And the demand for production equipment and electric energy is large, and the cost of equipment quantity, site area, supporting personnel, production time, production energy consumption and the like is increased. Disclosure of Invention In order to solve one or more of the above technical problems in the prior art, embodiments of the present application provide a new method and apparatus for drying a battery cell, which perform staged drying according to the distribution of moisture in the battery cell, so as to not only effectively reduce the drying time of the battery cell, but also prevent the whole battery cell from being damaged. In order to achieve the above purpose, the technical scheme adopted by the application for solving the technical problems is as follows: in a first aspect, the present application provides a method for drying a battery cell, where the method includes: The method comprises the steps of measuring the moisture content of a battery cell to be dried, judging a drying stage corresponding to the battery cell to be dried according to the moisture content, and executing a drying operation corresponding to the drying stage on the battery cell to be dried, wherein when the moisture content is larger than a first threshold value, the drying stage corresponding to the battery cell to be dried is a first stage, the drying operation corresponding to the first stage at least comprises the steps of executing a first operation, wherein the first operation comprises the steps of heating a vacuum oven for treating the battery cell to be dried to a first temperature at a first heating rate under a first vacuum degree, keeping a first time period, then performing a second operation, wherein the second operation comprises the steps of introducing inert gas to the vacuum oven to a second vacuum degree, vacuumizing the vacuum oven to the first vacuum degree, keeping a second time period, and repeating the second operation until the moisture content in the battery cell to be dried is lower than the first threshold value. In a specific embodiment, when the moisture content is between the first threshold and the second threshold, the drying stage corresponding to the to-be-dried battery cell is a second stage, and the drying operation corresponding to the second stage includes: Repeating a third operation until the moisture content in the battery core to be dried is lower than the second threshold value, wherein the third operation comprises the steps of heating the vacuum oven to a second temperature at a second heating rate under the first vacuum degree, introducing inert gas into the vacuum oven to the second vacuum degree after baking for a third period of time, and vacuumizing the vacuum oven to a third vacuum degree, wherein the second temperature is higher than the first temperature, the third period of time is higher than the second period of time, the second threshold value is lower than the first threshold value, and the third vacuum degree is not lower than the first vacuum degree. In a specific embodiment, when the moisture content is lower than the second threshold, the drying stage corresponding to the to-be-dried battery cell is a third stage, and the drying operation corresponding to the third stage includes: And repeating the fourth operation until the moisture content in the electric core to be dried meets the requirement, wherein the fourth operation comprises the steps of introducing inert gas into the vacuum oven until the pressure of the inert gas is a preset pressure value, and vacuumizing the vacuum oven to the first vacuum degree after maintaining the fourth time period. Preferably, the temperature of the inert gas differs from the temperature in the vacuum oven by ±10 ℃. In a specific embodiment, the inert gas comprises nitrogen. In a specific embodiment, the first threshold is 400ppm and/or the second threshold is 180ppm. In a specific embodiment, the first vacuum is 50-80pa, and/or the second vacuum is 85000-100000pa. Preferably, the second vacuum