阅读说明：本技术 一种退役磷酸铁锂动力电池分选方法和装置 (Sorting method and device for retired lithium iron phosphate power battery ) 是由 范茂松 杨凯 高飞 刘继东 李云亭 张健 刘皓 张明杰 耿萌萌 王康康 王凯丰 于 2018-06-29 设计创作，主要内容包括：本发明提供了一种退役磷酸铁锂动力电池分选方法和装置,所述方法包括下述步骤：(1)根据电池的历史数据将其进行分组；(2)分别对每组电池进行电学测试和机械测试,并得到电学测试结果和机械测试结果；(3)根据电学测试结果和机械测试结果分别确定每组电池的分选结果。该分选过程简单、条理清晰,分选效率大大提高,降低了分选过程的成本,提高了退役动力电池梯次利用的技术经济行,为退役磷酸铁锂动力电池的梯次利用提供了良好的技术指导。(The invention provides a sorting method and a device for retired lithium iron phosphate power batteries, wherein the method comprises the following steps: (1) grouping the batteries according to historical data of the batteries; (2) respectively carrying out electrical test and mechanical test on each group of batteries to obtain an electrical test result and a mechanical test result; (3) and respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result. The sorting process is simple and clear in order, the sorting efficiency is greatly improved, the cost of the sorting process is reduced, the technical economy of the gradient utilization of the retired power battery is improved, and good technical guidance is provided for the gradient utilization of the retired lithium iron phosphate power battery.)

1. A sorting method for retired lithium iron phosphate power batteries is characterized by comprising the following steps:

(1) grouping the batteries according to historical data of the batteries;

(2) respectively carrying out electrical test and mechanical test on each group of batteries to obtain an electrical test result and a mechanical test result;

(3) and respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result.

2. The method of claim 1, wherein the historical data of the battery comprises:

manufacturer, model, service life and retirement time.

3. The method of claim 1, wherein the grouping batteries according to their historical data comprises:

the batteries with the same manufacturer, the same type, the service life less than or equal to the service life threshold value and the retired time difference less than or equal to the retired time threshold value are divided into a group.

4. The method for sorting retired lithium iron phosphate power batteries according to claim 1, wherein the electrical test results comprise: self-discharge sorting parameters, capacity sorting parameters and direct-current internal resistance sorting parameters;

and carrying out electrical test on each group of batteries, and obtaining an electrical test result, wherein the electrical test result comprises the following steps:

charging the battery to a full-charge state of 3.65V at a temperature of 20-30 ℃ and a multiplying power of 0.5C, standing for 60min to obtain a first open-circuit voltage V serving as a self-discharge sorting parameter₁；

The battery is charged from the first open circuit voltage V with 0.5C multiplying power₁Discharging to 3.10V, standing for 30min, and recording the second open-circuit voltage V of the battery₂；

Discharging the battery for 10-15 s at 1.5-3.0C multiplying power with current I, and recording the third open circuit voltage V of the battery₃；

Voltage V of the battery is opened from the third by 0.5C multiplying power₃Discharging to 2.5V, recording discharge capacity as capacity sorting parameterQuantity C₁；

Calculating the direct current internal resistance R as a direct current internal resistance sorting parameter according to the following formula:

R＝(V₂-V₃)/I。

5. the method of claim 1, wherein the mechanical testing of each group of batteries comprises:

and detecting the appearance of the battery under a good light condition, and respectively determining whether the battery is damaged, deformed, swelled and leaked.

6. The method of claim 5, wherein after or before the battery appearance is detected under good light conditions to determine whether damage, deformation, swelling, and leakage are present, the method further comprises:

and detecting the internal structure of the battery under CT scanning, and respectively determining whether diaphragm wrinkles, pole piece falling, pole piece dislocation, diaphragm puncture and obvious lithium deposition on the surface of the negative electrode exist.

7. The method for sorting retired lithium iron phosphate power batteries according to claim 1, wherein the step of respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result comprises:

the electrical test result accords with an electrical sorting standard, the mechanical test result accords with a mechanical sorting standard, and the sorting result has a echelon utilization value;

the electrical test result does not accord with the electrical sorting standard or the mechanical test result does not accord with the mechanical sorting standard, and the sorting result has no echelon utilization value.

8. The method of claim 7, wherein the electrical sorting criteria comprise:

the electrical test result respectively meets the capacity sorting standard, the self-discharge sorting standard and the direct-current internal resistance sorting standard, and the electrical test result meets the electrical sorting standard;

the electrical test result does not accord with the capacity sorting standard, the self-discharge sorting standard or the direct-current internal resistance sorting standard, and the electrical test result does not accord with the electrical sorting standard;

the capacity sort criteria include:

discharge capacity C₁The battery which is more than or equal to 65 percent of the rated capacity and has the capacity difference with any other battery in the same group less than 5 percent meets the capacity sorting standard,

discharge capacity C₁Batteries with less than 65% of rated capacity or more than 5% of capacity difference with any other batteries in the same group do not meet the capacity sorting standard;

the self-discharge sorting criteria include:

first open-circuit voltage V after being fully charged and placed for 60min₁A battery having a voltage difference of 0.30V or less from the voltage at the full charge state meets the self-discharge evaluation criterion,

first open-circuit voltage V after being fully charged and placed for 60min₁The battery with the voltage difference larger than 0.30V in the full-charge state does not accord with the self-discharge evaluation standard;

the direct current internal resistance sorting standard comprises the following steps:

the batteries with the direct-current internal resistance R less than or equal to 3 times of the initial fixed-frequency internal resistance and the difference value with the direct-current internal resistance R of any battery in the same group less than 20 percent meet the sorting standard of the direct-current internal resistance,

the batteries with the direct current internal resistance R more than 3 times of the initial fixed frequency internal resistance or the difference value of the direct current internal resistance R with any battery in the same group more than or equal to 20 percent meet the sorting standard of the direct current internal resistance.

9. The method of claim 7, wherein the mechanical sorting criteria include:

the mechanical test results respectively meet the appearance sorting standard and the internal structure sorting standard, the battery meets the mechanical sorting standard,

the mechanical test result does not accord with the appearance sorting standard or the internal structure sorting standard, and the battery does not accord with the mechanical sorting standard;

the appearance sorting criteria include:

the battery without the conditions of damage, deformation, bulging and liquid leakage meets the appearance sorting standard,

batteries with damage, deformation, bulging or leakage do not meet the appearance sorting standard;

the internal structure sorting criteria include:

the battery without membrane wrinkles, pole piece falling, pole piece dislocation, membrane puncture and obvious lithium deposition on the surface of the negative electrode meets the internal structure sorting standard,

batteries with diaphragm wrinkles, pole piece shedding, pole piece dislocation, diaphragm puncture or obvious lithium deposition on the surface of the negative electrode do not meet the internal structure sorting standard.

10. The utility model provides a retired lithium iron phosphate power battery sorting unit which characterized in that, the device includes:

the grouping module is used for grouping the batteries according to historical data of the batteries;

the testing module is used for respectively carrying out electrical testing and mechanical testing on each group of batteries and obtaining an electrical testing result and a mechanical testing result;

and the determining module is used for respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result.

Technical Field

The invention relates to a method for sorting retired batteries, in particular to a method and a device for sorting retired lithium iron phosphate power batteries.

Background

In recent years, electric vehicles have been developed rapidly, and the electric vehicles use batteries as power sources, and the performance of the power batteries is continuously degraded in the use process. The performance requirement of the electric automobile on the power battery is high, and when the performance of the power battery is degraded to be incapable of meeting the use requirement of the electric automobile, the power battery must be replaced in order to ensure the power performance, the driving range and the safety in the use process of the electric automobile. The battery replaced from the electric automobile still has higher residual capacity. At present, batteries for electric vehicles are mainly lithium iron phosphate batteries which have the advantages of good safety, good environmental adaptability, long cycle life and the like, and after the batteries are retired from the electric vehicles, the batteries can still be possibly applied to occasions with relatively mild use working conditions and relatively low requirements on battery performance, so that the graded utilization of retired power batteries is realized. The echelon utilization of the power battery refers to that the power battery is continuously used as an electric energy storage device in other fields after the performance of the power battery is reduced and the use requirement of the electric automobile is not met.

At present, lithium iron phosphate batteries produced by battery manufacturing enterprises in China are different in models, and the running time and the retirement time of the batteries on electric vehicles are different. Meanwhile, even if the lithium iron phosphate batteries of the same manufacturer and the same model are used on a vehicle for a long time, the performance difference among the batteries is obviously increased, and the value of gradient utilization of part of the batteries is not achieved due to the fact that the capacity of the part of the batteries is too low and the internal resistance of the part of the batteries is too high. Therefore, for the retired lithium iron phosphate battery, the lithium iron phosphate battery needs to be sorted again before being used in a graded manner. The traditional battery sorting method is to test the capacity of the battery by charging and discharging for 3 times at a small multiplying power (usually 1/3), test the fixed-frequency internal resistance of the battery by an internal resistance tester and test the self-discharge performance of the battery at room temperature for 28 days. The method has long testing time, greatly increases the sorting cost of the retired power battery, and reduces the economy of the echelon utilization of the retired lithium iron phosphate battery.

Therefore, a method and a device for sorting the retired lithium iron phosphate power battery are needed to meet the defects of the prior art.

Disclosure of Invention

Aiming at the defects of the prior art, the applicant designs a sorting method and a sorting device for retired lithium iron phosphate power batteries; the sorting process is simple and clear in order, the sorting efficiency is greatly improved, the cost of the sorting process is reduced, the technical economy of the gradient utilization of the retired power battery is improved, and good technical guidance is provided for the gradient utilization of the retired lithium iron phosphate power battery.

The purpose of the invention is realized by the following technical scheme:

the invention provides a sorting method of retired lithium iron phosphate power batteries, which comprises the following steps:

(1) grouping the batteries according to historical data of the batteries;

(2) respectively carrying out electrical test and mechanical test on each group of batteries to obtain an electrical test result and a mechanical test result;

(3) and respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result.

Preferably, the historical data of the battery includes:

manufacturer, model, service life and retirement time.

Preferably, the grouping the batteries according to the historical data thereof includes:

the batteries with the same manufacturer, the same type, the service life less than or equal to the service life threshold value and the retired time difference less than or equal to the retired time threshold value are divided into a group.

Preferably, the electrical test result comprises: self-discharge sorting parameters, capacity sorting parameters and direct-current internal resistance sorting parameters;

and carrying out electrical test on each group of batteries, and obtaining an electrical test result, wherein the electrical test result comprises the following steps:

charging the battery to a full-charge state of 3.65V at a temperature of 20-30 ℃ and a multiplying power of 0.5C, standing for 60min to obtain a first open-circuit voltage V serving as a self-discharge sorting parameter₁；

The battery is charged from the first open circuit voltage V with 0.5C multiplying power₁Discharging to 3.10V, standing for 30min, and recording the second open-circuit voltage V of the battery₂；

Discharging the battery for 10-15 s at 1.5-3.0C multiplying power with current I, and recording the third open circuit voltage V of the battery₃；

Voltage V of the battery is opened from the third by 0.5C multiplying power₃Discharge to 2.5V and recording discharge capacity C as a capacity sorting parameter₁；

Calculating the direct current internal resistance R as a direct current internal resistance sorting parameter according to the following formula:

R＝(V₂-V₃)/I。

preferably, the mechanical testing of each group of cells comprises:

and detecting the appearance of the battery under a good light condition, and respectively determining whether the battery is damaged, deformed, swelled and leaked.

Preferably, the detecting the appearance of the battery under good light conditions, after or before determining whether the conditions of breakage, deformation, swelling and leakage exist, further comprises:

and detecting the internal structure of the battery under CT scanning, and respectively determining whether diaphragm wrinkles, pole piece falling, pole piece dislocation, diaphragm puncture and obvious lithium deposition on the surface of the negative electrode exist.

Preferably, the determining the sorting result of each group of cells according to the electrical test result and the mechanical test result respectively includes:

the electrical test result accords with an electrical sorting standard, the mechanical test result accords with a mechanical sorting standard, and the sorting result has a echelon utilization value;

the electrical test result does not accord with the electrical sorting standard or the mechanical test result does not accord with the mechanical sorting standard, and the sorting result has no echelon utilization value.

Preferably, the electrical sorting criterion comprises:

the electrical test result respectively meets the capacity sorting standard, the self-discharge sorting standard and the direct-current internal resistance sorting standard, and the electrical test result meets the electrical sorting standard;

the electrical test result does not accord with the capacity sorting standard, the self-discharge sorting standard or the direct-current internal resistance sorting standard, and the electrical test result does not accord with the electrical sorting standard;

the capacity sort criteria include:

discharge capacity C₁The battery which is more than or equal to 65 percent of the rated capacity and has the capacity difference with any other battery in the same group less than 5 percent meets the capacity sorting standard,

discharge capacity C₁Batteries with less than 65% of rated capacity or more than 5% of capacity difference with any other batteries in the same group do not meet the capacity sorting standard;

the self-discharge sorting criteria include:

first open-circuit voltage V after being fully charged and placed for 60min₁A battery having a voltage difference of 0.30V or less from the voltage at the full charge state meets the self-discharge evaluation criterion,

first open-circuit voltage V after being fully charged and placed for 60min₁The difference value between the voltage of the battery and the voltage in the full-charge state is more than 0.30VMeeting the self-discharge evaluation standard;

the direct current internal resistance sorting standard comprises the following steps:

the batteries with the direct-current internal resistance R less than or equal to 3 times of the initial fixed-frequency internal resistance and the difference value with the direct-current internal resistance R of any battery in the same group less than 20 percent meet the sorting standard of the direct-current internal resistance,

the batteries with the direct current internal resistance R more than 3 times of the initial fixed frequency internal resistance or the difference value of the direct current internal resistance R with any battery in the same group more than or equal to 20 percent meet the sorting standard of the direct current internal resistance.

Preferably, the mechanical sorting criteria include:

the mechanical test results respectively meet the appearance sorting standard and the internal structure sorting standard, the battery meets the mechanical sorting standard,

the mechanical test result does not accord with the appearance sorting standard or the internal structure sorting standard, and the battery does not accord with the mechanical sorting standard;

the appearance sorting criteria include:

the battery without the conditions of damage, deformation, bulging and liquid leakage meets the appearance sorting standard,

batteries with damage, deformation, bulging or leakage do not meet the appearance sorting standard;

the internal structure sorting criteria include:

the battery without membrane wrinkles, pole piece falling, pole piece dislocation, membrane puncture and obvious lithium deposition on the surface of the negative electrode meets the internal structure sorting standard,

batteries with diaphragm wrinkles, pole piece shedding, pole piece dislocation, diaphragm puncture or obvious lithium deposition on the surface of the negative electrode do not meet the internal structure sorting standard.

Based on the same invention concept, the invention also provides a sorting device for the retired lithium iron phosphate power battery, which comprises:

the grouping module is used for grouping the batteries according to historical data of the batteries;

the testing module is used for respectively carrying out electrical testing and mechanical testing on each group of batteries and obtaining an electrical testing result and a mechanical testing result;

and the determining module is used for respectively determining the sorting result of each group of batteries according to the electrical test result and the mechanical test result.

Compared with the closest prior art, the invention has the beneficial effects that:

1. according to the technical scheme provided by the invention, the batteries are grouped according to the historical data of the batteries, then the batteries in each group are tested mechanically and electrically, and finally the sorting result is determined. The grouped batteries have similar conditions and good consistency; the test is comprehensive and accurate, and the accuracy of the sorting result is improved; the sorting process is simple and clear in order, the sorting efficiency is greatly improved, the cost of the sorting process is reduced, the technical economy of the gradient utilization of the retired power battery is improved, and good technical guidance is provided for the gradient utilization of the retired lithium iron phosphate power battery.

2. According to the technical scheme provided by the invention, in an electrical test, the comprehensive detection of the capacity, the internal resistance and the self-discharge characteristic of the battery is realized through one-time rapid charging and discharging, the detection result is simple and accurate, the operation is convenient, the test efficiency is greatly improved, and the sorting efficiency is further improved.

Detailed Description

The technical solutions in the embodiments of the present application are clearly and completely described below.