阅读说明：本技术 低能耗锂电池电芯干燥方法 (Low-energy-consumption lithium battery core drying method ) 是由 孟健 庄晓慧 褚帅 周会 王勇 薛娟娟 于 2020-12-14 设计创作，主要内容包括：本发明属于锂电池技术领域,涉及一种低能耗锂电池电芯干燥方法。发明采用的技术方案是：包括以下步骤,将锂电芯放入真空干燥箱中先进行真空环境下预热,然后持续对预热后的锂电芯进行加热；对锂电芯以60℃的环境对持续干燥,然后对干燥箱抽真空,真空干燥箱的温度降低至45℃以下时停止真空泵工作；往真空干燥箱中通入干燥氮气,使干燥箱卸真空至常压,等待真空干燥箱内的温度降低至40℃以后,得到真空干燥后的锂电芯。本发明锂电芯烘烤采用高压抽真空方式,能耗低,烘烤一致性好,稳定性提高；烘烤时从内层到外层受热均匀,大大降低了锂电芯内外层水分差异；降低锂电芯水分含量,提高了锂电池的容量和循环性能。(The invention belongs to the technical field of lithium batteries, and relates to a low-energy-consumption lithium battery core drying method. The technical scheme adopted by the invention is as follows: the method comprises the following steps of putting a lithium battery cell into a vacuum drying oven, preheating the lithium battery cell in a vacuum environment, and continuously heating the preheated lithium battery cell; continuously drying the lithium battery cell in an environment of 60 ℃, then vacuumizing a drying oven, and stopping the vacuum pump when the temperature of the vacuum drying oven is reduced to below 45 ℃; and introducing dry nitrogen into the vacuum drying oven, vacuumizing the drying oven to normal pressure, and waiting for the temperature in the vacuum drying oven to be reduced to 40 ℃ to obtain the vacuum-dried lithium battery core. According to the invention, the lithium battery cell is baked in a high-pressure vacuumizing mode, so that the energy consumption is low, the baking consistency is good, and the stability is improved; during baking, the lithium battery core is uniformly heated from the inner layer to the outer layer, so that the moisture difference of the inner layer and the outer layer of the lithium battery core is greatly reduced; the moisture content of the lithium battery core is reduced, and the capacity and the cycle performance of the lithium battery are improved.)

1. A low-energy consumption lithium battery core drying method is characterized by comprising the following steps,

step 1) placing a lithium battery cell into a vacuum drying oven, preheating the lithium battery cell in a vacuum environment, and continuously heating the preheated lithium battery cell to 60-70 ℃, wherein the heating process is circulated for 3-4 times;

step 2) vacuum drying, namely continuously drying the circulated lithium battery cell for 10-20 min in an environment of 60 ℃, then vacuumizing a drying oven, and stopping the vacuum pump when the temperature of the vacuum drying oven is reduced to below 45 ℃;

and 3) introducing dry nitrogen into the vacuum drying oven, vacuumizing the drying oven to normal pressure, and waiting until the temperature in the vacuum drying oven is reduced to 40 ℃ to obtain the vacuum-dried lithium battery core.

2. The method for drying the low-energy lithium battery cell of claim 1, wherein in the step 1), the preheated lithium battery cell is preheated under a high vacuum of-0.5 Kpa for 5min to 10min at a preheating temperature of 80 ℃.

3. The method for drying the battery cell of the low-energy lithium battery as claimed in claim 1, wherein in the step 1), the lithium battery cell is placed at a density of 26650 battery cells of 10000-³ 18650 cells 22000-³。

4. The method for drying the low-energy lithium battery cell of claim 1, wherein the size of the lithium battery cell is consistent with the size of a mold in a vacuum drying oven.

Technical Field

The invention belongs to the technical field of lithium batteries, and relates to a low-energy-consumption lithium battery core drying method.

Background

The lithium battery is widely applied to electronic products due to high energy density, and with the continuous development of new energy industry, the market has higher and higher requirements on the energy density of the battery, and particularly at the present day when new energy automobiles are increasingly popular, the lithium battery not only needs to have excellent power performance, but also needs to have excellent cycle performance so as to maintain the cruising ability of the battery.

The drying of the lithium battery core has a great effect on the capacity and the cycle performance of the lithium battery. The water in the lithium battery reacts with the lithium battery electrolyte (lithium hexafluorophosphate) to generate hydrofluoric acid, and the hydrofluoric acid has strong corrosivity and can react with the anode material (lithium iron phosphate), so that lithium ions are consumed, and the capacity and the cycle performance of the lithium battery are reduced.

At present, take to lead to nitrogen gas with the oven evacuation for moisture content in the reduction lithium cell, discharge the vapor in the oven, but when the great drying that is unfavorable for every lithium cell bottom moisture of lithium cell density of lithium cell, lithium cell moisture content is higher, influences the processability of lithium cell. Therefore, a more precise and novel baking method for lithium batteries is required.

Disclosure of Invention

The invention provides a low-energy-consumption lithium battery core drying method which reduces energy consumption by controlling the density of a lithium battery during drying, reduces the moisture content in the lithium battery and improves the performance of the lithium battery.

In order to achieve the purpose, the invention adopts the technical scheme that:

the drying method of the low-energy-consumption lithium battery cell comprises the following steps,

step 1) placing a lithium battery cell into a vacuum drying oven, preheating the lithium battery cell in a vacuum environment, and continuously heating the preheated lithium battery cell to 60-70 ℃, wherein the heating process is circulated for 3-4 times;

step 2) vacuum drying, namely continuously drying the circulated lithium battery cell for 10-20 min in an environment of 60 ℃, then vacuumizing a drying oven, and stopping the vacuum pump when the temperature of the vacuum drying oven is reduced to below 45 ℃;

and 3) introducing dry nitrogen into the vacuum drying oven, vacuumizing the drying oven to normal pressure, and waiting until the temperature in the vacuum drying oven is reduced to 40 ℃ to obtain the vacuum-dried lithium battery core.

Preferably, in the step 1), the preheating of the lithium battery cell is carried out under a high vacuum of-0.5 Kpa for 5min to 10min at a preheating temperature of 80 ℃.

Preferably, in the step 1), the placing density of the lithium battery cells is 26650 battery cells 10000-³ 18650 cells 22000-³。

Preferably, the lithium battery cell size is consistent with the size of the mold in the vacuum drying oven.

Compared with the prior art, the invention has the advantages that:

1. the lithium battery cell is baked in a high-voltage vacuumizing mode, so that the lithium battery cell is baked under low energy consumption;

2. the baking density is controlled in the baking process of the lithium battery cell, so that the baking consistency is improved;

3. the baking stability of the lithium battery cell is improved through multiple cycles of baking the lithium battery cell;

4. when the lithium battery cell is baked, the lithium battery cell is uniformly heated from the inner layer to the outer layer, so that the moisture difference between the inner layer and the outer layer of the lithium battery cell is greatly reduced;

5. the moisture content of the lithium battery cell is reduced by changing the baking mode of the lithium battery cell, and the capacity and the cycle performance of the lithium battery are improved;

6. the invention has low energy consumption, simple operation and easy implementation.

Drawings

Fig. 1 a lithium battery baking tray structure according to the present invention.

Fig. 2 is a diagram of a lithium battery cell baking apparatus according to the present invention.

Fig. 3 shows the moisture content of the lithium battery cell of the present invention before and after baking.

Reference numerals: 1. the device comprises a vacuum unit, 2, a vacuum pipeline, 3, a vacuum oven, 4, a cold air return inlet, 5, a cold air outlet, 6 and an air cooler.

Detailed Description

The present application is further described by the following examples, which are only a part of the examples of the present invention and do not limit the present application in any way.

Example 1

The specific embodiment of 18650-1800mAh-3.2V lithium iron phosphate core baking provided by the embodiment of the invention.

Firstly, putting 18650-1800mAh-3.2V lithium iron phosphate cores into a vacuum oven, and closing the oven door; then, opening a switch of a vacuum oven, heating to 80 ℃, and vacuumizing to be below 0.3 Kpa; setting the baking cycle times to be 4-6 times; and finally, introducing dry nitrogen into the oven, vacuumizing the vacuum oven to normal pressure, and cooling.

Example 2

This example is a specific example of baking for preparing 18650-2200mAh-3.6V lithium iron phosphate cells.

Firstly, putting 18650-2200mAh-3.6V lithium iron phosphate cores into a vacuum oven, and closing the oven door; secondly, opening a switch of a vacuum oven, heating to 80 ℃, and vacuumizing to be below 0.3 Kpa; setting the baking cycle times to be 4-6 times; and finally, introducing dry nitrogen into the oven, vacuumizing the vacuum oven to normal pressure, and cooling.

Example 3

This example is a specific example of baking for preparing 26650-3800 mAh-3.2V lithium iron phosphate cells.

Firstly, placing 26650-3800 mAh-3.2V lithium iron phosphate cores into a vacuum oven, and closing the oven door; secondly, opening a switch of a vacuum oven, heating to 80 ℃, and vacuumizing to be below 0.3 Kpa; setting the baking cycle times to be 4-6 times; and finally, introducing dry nitrogen into the oven, vacuumizing the vacuum oven to normal pressure, and cooling.