阅读说明：本技术 一种锂离子电池的新型活化工艺 (Novel activation process of lithium ion battery ) 是由 杜纪磊 高立海 张金煌 刘晓龙 张鹏 张莎莎 杨玉宝 李新强 张宏光 于 2019-10-11 设计创作，主要内容包括：本发明公开了一种锂离子电池的新型活化工艺,所述该工艺具体包括以下步骤：1)化成充电：采用限压、限流、限时化成充电,环境温度为23±2℃、湿度≤10％；2)封口：在温度23±2℃,露点-40度以下的环境中对电池进行真空封口操作；3)预充电：采用限压、限流、限容充电,环境温度为23±2℃；4)电池高温老化：转入高温搁置室进行老化48h,高温搁置室温度为45±2℃；5)化成放电：采用限压、限流、限时化成放电,环境温度为23±2℃；6)压降测试：化成放电结束24h后测量并记录每只单体电池的开路电压,测试完成后,电池放到指定位置进行常温搁置,本发明缩短了工序整体时间及优化了流程,节省了电池上下柜的人工成本以及分容时的能耗。(the invention discloses a novel activation process of a lithium ion battery, which specifically comprises the following steps: 1) formation charging: the voltage limiting, current limiting and time limiting formation charging is adopted, the ambient temperature is 23 +/-2 ℃, and the humidity is less than or equal to 10 percent; 2) and (3) sealing: carrying out vacuum sealing operation on the battery in an environment with the temperature of 23 +/-2 ℃ and the dew point of-40 ℃; 3) pre-charging: voltage limiting, current limiting and capacity limiting charging are adopted, and the ambient temperature is 23 +/-2 ℃; 4) and (3) high-temperature aging of the battery: aging in a high-temperature holding room for 48h, wherein the temperature of the high-temperature holding room is 45 +/-2 ℃; 5) formation discharge: adopting voltage limiting, current limiting and time limiting formation discharge, wherein the ambient temperature is 23 +/-2 ℃; 6) and (3) pressure drop test: and measuring and recording the open-circuit voltage of each single battery 24 hours after formation discharge is finished, and placing the battery at a specified position for normal-temperature placement after the test is finished.)

1. A novel activation process of a lithium ion battery is characterized by comprising the following steps:

1) Formation charging: the method adopts voltage limiting, current limiting and time limiting formation charging, and has the following environmental requirements: the temperature is 23 +/-2 ℃, and the humidity is less than or equal to 10 percent;

2) and (3) sealing: carrying out vacuum sealing operation on the battery in an environment with the temperature of 23 +/-2 ℃ and the dew point of-40 ℃;

3) Pre-charging: voltage limiting, current limiting and capacity limiting charging are adopted, and the ambient temperature is kept at 23 +/-2 ℃;

4) And (3) high-temperature aging of the battery: aging in a high-temperature shelf room at 45 + -2 deg.C for 48 h;

5) formation discharge: adopting voltage limiting, current limiting and time limiting to form discharge, and keeping the temperature at 23 +/-2 ℃;

6) and (3) pressure drop test: and measuring and recording the open-circuit voltage (OCV 1) of each single battery 24h after formation discharge is finished, and placing the battery at a specified position for normal-temperature standing after the OCV1 test is finished.

2. The novel activation process of a lithium ion battery according to claim 1, characterized in that: the voltage limiting, the current limiting and the time limiting formation charging adopted in the step 1) are completed in three stages:

The first stage is as follows: placing the battery on a cabinet for 1min, starting constant current charging with 0.02C, limiting the voltage to 3.2V, and keeping the time for 120 min;

and a second stage: charging with 0.05C constant current, limiting voltage to 3.2V, and maintaining for 60 min;

And a third stage: continuously charging with 0.1C constant current for 80min, with a voltage limit of 3.65V; standing for 10 min.

3. The novel activation process of a lithium ion battery according to claim 2, characterized in that: and detecting the voltage of the battery cell after the formation charging is finished, if the detected voltage value is less than or equal to 3200mV, the battery cell is unqualified, the battery cell needs to be put into a cabinet again for formation charging, and if the voltage is more than 3200mV, the battery cell is qualified.

4. The novel activation process of a lithium ion battery according to claim 3, characterized in that: tearing off the Mala tape at the position of the battery liquid injection hole after the formation charging is completed in the step 2), and then vacuumizing for the following time: making the vacuum degree less than-0.09 Mpa; and after the vacuum pumping is finished, injecting nitrogen (the dew point of the nitrogen is below-40 ℃), taking out the battery, putting the battery into a tool, and extruding and sealing the battery according to the thickness requirement.

5. the novel activation process of a lithium ion battery according to claim 4, characterized in that: the sealing operation in the step 2) needs to be completed within 1-1.5 h after the formation charging is finished.

6. The novel activation process of a lithium ion battery according to claim 5, characterized in that: when the pre-charging is carried out in the step 3), firstly, the battery is placed on a cabinet for 2 min; starting to charge by using a 0.1C constant current, limiting the voltage to 3.7V and limiting the capacity to 1/2 battery nominal capacity; the battery was left for 1min after the precharge was completed.

7. the novel activation process of a lithium ion battery according to claim 6, characterized in that: and (3) after the pre-charging process in the step 3) is finished, checking whether the charging capacity is 1/2 nominal capacity and is cut off, turning to a high-temperature aging process if the charging capacity is qualified according to the requirement, and intensively placing unqualified batteries.

8. The novel activation process of a lithium ion battery according to claim 7, characterized in that: the voltage limiting, current limiting and time limiting formation discharging adopted by the battery in the step 5) is completed in two stages:

the first stage is as follows: charging to 3.7V with 0.3C constant current, charging at 3.7V with constant voltage, and stopping current at 0.02C; standing for 20min after charging; discharging to 2.5V at 0.3C; standing for 10 min;

And a second stage: charging at constant current of 0.3C, limiting voltage to 3.7V, and limiting time for 20 min.

9. The novel activation process of a lithium ion battery according to claim 8, characterized in that: the standing time at normal temperature in the step 6): 96h, resting temperature: 20 ℃; after the laying, the open-circuit voltage and the shell voltage of each battery are measured.

10. the novel activation process of a lithium ion battery according to claim 9, characterized in that: and 6) after the voltage drop test is finished, selecting and grading the batteries according to the standard through capacity, internal resistance, thickness, appearance, shell voltage and voltage drop rate.

Technical Field

The invention relates to a battery activation process, in particular to a novel activation process of a lithium ion battery, which is suitable for a lithium iron phosphate battery, can effectively shorten the activation time of the lithium battery and reduce the energy consumption in the battery manufacturing process, and belongs to the technical field of new energy batteries.

background

At present, petroleum resources are gradually in shortage, environmental pollution is increasingly serious, new energy is urgently developed to replace traditional petrochemical energy, and under the background, the development of a lithium ion battery free of environmental pollution is particularly important to be accelerated.

Under the strong support of the state, the lithium ion battery industry is rapidly developed in recent years, and although the manufacturing steps of the battery are slightly different, the manufacturing steps are basically consistent: stirring, coating, rolling, tabletting, forming a core, welding, drying, injecting liquid, standing, forming charging, sealing, forming discharging, battery aging, OCV testing, grading, selecting and shipping. Formation charge-sealing-formation discharge-battery aging-OCV test-capacity grading can be referred to as the activation stage of the battery.

The purpose of the formation of the battery is to activate the positive and negative electrode materials by conducting the first several charge and discharge operations, and to make the materials in an optimum state of use.

The purposes of aging are mainly: firstly, the electrolyte is better infiltrated; secondly, accelerating some side reactions, such as gas generation, electrolyte decomposition and the like, so that the electrochemical performance of the lithium battery is rapidly stabilized; thirdly, the aged battery cell has more stable voltage and internal resistance, and is convenient for screening the battery with high consistency.

The battery can be subjected to capacity, voltage drop, internal resistance and thickness selection after aging, and in the prior art, the aging of the battery is carried out after formation charge and discharge and before capacity grading, and the process has the following defects: firstly, the formed discharge capacity is inaccurate, and the performance judgment is influenced; secondly, an OCV measurement error is caused by unstable voltage of the battery after formation; thirdly, the whole activation time is longer.

Disclosure of Invention

The invention aims to solve the main technical problem of providing a novel activation process of a lithium ion battery, which is suitable for a lithium iron phosphate battery, can effectively shorten the activation time of the lithium battery and reduce the energy consumption in the battery manufacturing process.

In order to solve the technical problems, the invention provides the following technical scheme:

A novel activation process of a lithium ion battery specifically comprises the following steps:

1) Formation charging: the method adopts voltage limiting, current limiting and time limiting formation charging, and has the following environmental requirements: the temperature is 23 +/-2 ℃, and the humidity is less than or equal to 10 percent;

2) And (3) sealing: carrying out vacuum sealing operation on the battery in an environment with the temperature of 23 +/-2 ℃ and the dew point of-40 ℃;

3) Pre-charging: voltage limiting, current limiting and capacity limiting charging are adopted, and the ambient temperature is kept at 23 +/-2 ℃;

4) and (3) high-temperature aging of the battery: aging in a high-temperature shelf room at 45 + -2 deg.C for 48 h;

5) Formation discharge: adopting voltage limiting, current limiting and time limiting to form discharge, and keeping the temperature at 23 +/-2 ℃;

6) and (3) pressure drop test: and measuring and recording the open-circuit voltage (OCV 1) of each single battery 24h after formation discharge is finished, and placing the battery at a specified position for normal-temperature standing after the OCV1 test is finished.

the following is a further optimization of the above technical solution of the present invention:

the voltage limiting, the current limiting and the time limiting formation charging adopted in the step 1) are completed in three stages:

The first stage is as follows: placing the battery on a cabinet for 1min, starting constant current charging with 0.02C, limiting the voltage to 3.2V, and keeping the time for 120 min;

And a second stage: charging with 0.05C constant current, limiting voltage to 3.2V, and maintaining for 60 min;

And a third stage: continuously charging with 0.1C constant current for 80min, with a voltage limit of 3.65V; standing for 10 min.

Further optimization: and detecting the voltage of the battery cell after the formation charging is finished, if the detected voltage value is less than or equal to 3200mV, the battery cell is unqualified, the battery cell needs to be put into a cabinet again for formation charging, and if the voltage is more than 3200mV, the battery cell is qualified.

Further optimization: tearing off the Mala tape at the position of the battery liquid injection hole after the formation charging is completed in the step 2), and then vacuumizing for the following time: making the vacuum degree less than-0.09 Mpa; and after the vacuum pumping is finished, injecting nitrogen (the dew point of the nitrogen is below-40 ℃), taking out the battery, putting the battery into a tool, and extruding and sealing the battery according to the thickness requirement.

Further optimization: the sealing operation in the step 2) needs to be completed within 1-1.5 h after the formation charging is finished.

further optimization: when the pre-charging is carried out in the step 3), firstly, the battery is placed on a cabinet for 2 min; starting to charge by using a 0.1C constant current, limiting the voltage to 3.7V and limiting the capacity to 1/2 battery nominal capacity; the battery was left for 1min after the precharge was completed.

Further optimization: and (3) after the pre-charging process in the step 3) is finished, checking whether the charging capacity is 1/2 nominal capacity and is cut off, turning to a high-temperature aging process if the charging capacity is qualified according to the requirement, and intensively placing unqualified batteries.

further optimization: the voltage limiting, current limiting and time limiting formation discharging adopted by the battery in the step 5) is completed in two stages:

The first stage is as follows: charging to 3.7V with 0.3C constant current, charging at 3.7V with constant voltage, and stopping current at 0.02C; standing for 20min after charging; discharging to 2.5V at 0.3C; standing for 10 min;

And a second stage: charging at constant current of 0.3C, limiting voltage to 3.7V, and limiting time for 20 min.

further optimization: the standing time at normal temperature in the step 6): 96h, resting temperature: 20 ℃; after the laying, the open-circuit voltage and the shell voltage of each battery are measured.

Further optimization: and 6) after the voltage drop test is finished, selecting and grading the batteries according to the standard through capacity, internal resistance, thickness, appearance, shell voltage and voltage drop rate.

By adopting the technical scheme, the aging time point is optimized, the battery aging process is moved forward, the battery is aged for 48 hours at the temperature of 45 +/-2 ℃ before formation discharge under the premise of ensuring that an SEI film is formed and the early-stage gas generation is formed into a key control point, the electrolyte is completely soaked before the formation discharge, side reactions in the battery are quickly completed, the electrochemical performance of the battery is quickly stabilized, the voltage and the internal resistance of the battery are stabilized, the discharge capacity during the formation discharge is accurate and can be used as a capacity calibration basis, so that the capacity grading process step can be omitted, the whole process time is shortened, the process flow is optimized, and the labor cost of loading and unloading the battery and the energy consumption during the capacity grading are saved.

The present invention will be further described with reference to the following examples.

Detailed Description