WO2021082341A1

WO2021082341A1 - Rapid grouping and repairing method for recycled batteries

Info

Publication number: WO2021082341A1
Application number: PCT/CN2020/080177
Authority: WO
Inventors: 刘晨露; 王海涛; 邓波; 罗勇; 孟超; 刘卫强
Original assignee: 深圳市普兰德储能技术有限公司
Priority date: 2019-10-29
Filing date: 2020-03-19
Publication date: 2021-05-06
Also published as: AU2020203011B2; AU2020203011A1; DE112020005205T5; GB202019104D0; CN110797591A; JP7076495B2; CN110797591B; GB2599453A; JP2021072275A; SG11202003909PA

Abstract

A rapid grouping and repairing method for recycled batteries, which relates to the technical field of recycle and reuse of lithium ion batteries. The method comprises: rapidly grouping recycled batteries by using a key voltage value in a non-full charging and non-full discharging manner, then selecting one or more recycled batteries in each group for measurement of the actual capacities thereof, and according to the actual capacities, screening out a group of recycled batteries which can be repaired; discharging the recycled batteries to cut-off voltages thereof; injecting electrolytes of different weights into the recycled batteries, and sealing same, and finally activating the recycled batteries; after activation, regrouping the recycled batteries according to battery discharging capacities and charge transfer impedance; and forming a battery pack of activated recycled batteries in the same group, and reusing same. The capacity of a battery repaired by using the method can be restored to the level of an on-service power battery, and a battery pack formed by using the method has a good recycling performance.

Description

Fast grouping and repairing methods of retired batteries

Technical field

This application relates to the technical field of lithium ion battery repair, and in particular to a method for rapid grouping and repair of retired batteries.

Background technique

Electric vehicles have been popularized for several years, and a large number of lithium-ion batteries with insufficient capacity and performance degradation caused by long-term use have been produced.

The loss of battery capacity is mainly caused by the increase in impedance caused by the loss of lithium ions and the side reaction caused by the consumption of electrolyte.

The lost lithium ions mainly include lithium consumed by the formation of SEI film in the battery formation process, lithium consumed by side reactions in the electrolyte, lithium dendrites generated by lithium in the negative electrode, and lithium ion reception caused by changes in the structure of the active material. Loss of lithium caused by missing vacancies. The irreversible capacity loss caused by these lithium losses is irreparable.

The electrolyte is the medium through which lithium ions are conducted between the positive and negative electrodes. During the charging and discharging process, the electrolyte will react with the pole pieces, and the electrolyte will be lost, and the resulting concentration polarization resistance and charge transfer resistance are paired The capacity decay of the battery has an impact, and the capacity of the lithium battery can be repaired by replenishing the electrolyte.

technical problem

In the prior art, the actual capacity parameters of the decommissioned batteries are first fully charged to obtain the actual capacity parameters of the decommissioned batteries. According to the actual capacity, the repairable decommissioned batteries are selected, and then the repairable decommissioned batteries are classified into different files, and the decommissioned batteries of each file are charged. Into the corresponding weight of electrolyte. This method needs to fully charge all retired batteries, and charging and discharging all retired batteries consumes a lot of power.

Technical solutions

The object of the present invention is to provide a fast grouping and repairing method for retired batteries, which can save power consumption and reduce production costs.

In order to achieve the above objective, the technical solution of the present invention is:

A fast grouping method for retired batteries includes the following steps:

The decommissioned battery discharged to the cut-off voltage is allowed to stand for a first set period of time at room temperature, and the voltage of the decommissioned battery at this time is measured and recorded as the first voltage;

Charge the decommissioned battery to a rated capacity that is a preset percentage of the nominal capacity according to the original charging method of the decommissioned battery, measure the voltage of the decommissioned battery at this time, and record it as the second voltage;

Standing the retired battery charged with the rated capacity for a second set period of time at room temperature, measuring the voltage of the retired battery at this time, and recording it as the third voltage;

A first judgment condition is set according to the first voltage, a second judgment condition is set according to the second voltage, a third judgment condition is set according to the third voltage, and a third judgment condition is set according to the first judgment condition, the second judgment condition, and the first judgment condition. 3. Judgment conditions sequentially judge the retired batteries;

Complete the above judgment steps for a number of retired batteries to form a first preselected group, a second preselected group, and a third preselected group; and

The retired batteries that are simultaneously selected into the first preselected group, the second preselected group, and the third preselected group are divided into one group.

A method for repairing decommissioned batteries includes the following steps:

Complete the above judgment steps for a number of retired batteries to form a first preselected group, a second preselected group, and a third preselected group;

Dividing the retired batteries that are simultaneously selected into the first preselection group, the second preselection group, and the third preselection group into one group;

Adjusting the first judgment condition, the second judgment condition, and the third judgment condition, and group all retired batteries to obtain a number of retired battery packs;

Select one or more retired batteries from each of the retired battery packs, and detect the actual capacity of the selected retired batteries;

According to the actual capacity of the selected decommissioned batteries, select repairable decommissioned battery packs;

Discharging each decommissioned battery in each repairable decommissioned battery pack to its cut-off voltage;

Inject the decommissioned battery in each repairable decommissioned battery pack with a corresponding weight of electrolyte, and then seal it; wherein, each decommissioned battery in the repairable decommissioned battery pack is injected with the same weight of the electrolyte; as well as

The decommissioned battery injected with the electrolyte is charged and discharged for activation.

Beneficial effect

Implementing the embodiments of this application will have the following beneficial effects:

In the present invention, the three key voltage values that can characterize the battery performance are first obtained by not charging the battery to full charge. By setting the judgment condition, the rapid grouping of all retired batteries is realized. The electrical performance of the same group of retired batteries is similar, shortening Test time, save energy consumption.

Since the electrical properties of the same group of retired batteries are similar, one or more batteries in each group of retired batteries are selected to be fully charged and fully discharged, and their actual capacity is measured. The actual capacity can represent the capacity level of the same group of retired batteries. The measured actual capacity selects repairable decommissioned battery packs, and then according to the measured actual capacity, the corresponding weight of electrolyte is injected into each group of repairable decommissioned batteries to restore the decommissioned batteries to the level of in-service power batteries. Since only one or more batteries in each group are fully charged and discharged, the number of fully charged batteries is greatly reduced. Therefore, energy consumption is greatly reduced and production costs are saved.

Since the internal electrolyte of the repaired battery is different from that of a fresh battery, the present invention re-sorts and allocates the retired batteries after repair from the aspects of battery capacity and battery charge transfer impedance. The consistency ratio is sorted by capacity and internal resistance. Better, it improves the recycling performance of the battery pack.

The fast grouping and repairing method of the present invention is more suitable for batch repairs and automated operations to improve production efficiency.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

among them:

Figure 1 shows the relationship between the voltage and the capacity of a lithium battery during normal charging and discharging.

Fig. 2 is a comparison diagram of discharge curves of a LiFePO4/graphite decommissioned battery with a nominal capacity of 150Ah before and after refilling electrolyte and activation in an embodiment of the present invention.

FIG. 3 is a comparison diagram of normal temperature cycling performance of two battery packs obtained by using different grouping methods in an embodiment of the present invention.

Embodiments of the present invention

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of this application.

The invention aims at repairing the battery whose capacity is attenuated due to electrolyte loss, so that it can reach the level of in-service power battery, and is re-sorted and paired to continue to be used on power battery vehicles and recycled.

How to select repairable decommissioned batteries from decommissioned batteries? In the prior art, the battery is usually fully charged and left at room temperature for 5 days or more before testing the voltage to obtain the voltage drop and actual capacity data, and then discharge to a constant current. The cut-off voltage is used to obtain the actual capacity of the battery. This sorting method takes a long time, and at the same time, full charge also consumes a lot of power resources. The four parameters reflecting battery consistency, internal resistance, voltage, capacity, and self-discharge rate, are the key control points for battery sorting. As shown in Figure 1, it is a charge-discharge curve diagram of a lithium battery, where the ordinate is the voltage, and the abscissa is the cumulative capacity of the charge and discharge. That is, the cumulative value of the charged or discharged capacity over time during charging or discharging. If the abscissa is changed to time, it can be understood as the change in cell voltage over time during charging or discharging. It can be seen that in a single charging process or discharging process, the voltage and the capacity value have a one-to-one correspondence, which is also the fundamental basis for this patent to use voltage to characterize the capacity.

In this embodiment, by detecting the key voltage parameters of each battery, multiple judgment conditions related to internal resistance, voltage, capacity, and self-discharge are set to reflect the battery consistency parameters, so that the battery is not fully charged and the battery is fully charged. The characterization quantity of battery capacity and voltage difference, while improving the performance and matching of the recombined battery, shortening the test time and reducing the test energy consumption.

The method for rapid sorting of lithium batteries in this embodiment is aimed at retired batteries of the same model and batch produced by the same manufacturer. On the premise of retired batteries of the same model and batch, the specific voltage conditions are associated with other performance parameters of the battery. For different types of batteries, the correlation of performance parameters is not the same. In addition, different types of batteries have different shapes, so different types and batchs of retired batteries are not reorganized.

The present invention provides a fast grouping method for retired batteries, which does not fully discharge the batteries, shortens the sorting time, improves the sorting efficiency, and saves power at the same time, including the following steps:

(1) Leave the decommissioned battery discharged to the cut-off voltage at room temperature for the first set time, measure the voltage of the decommissioned battery at this time, and record it as the first voltage. The first voltage can reflect the polarization internal resistance of the battery.

In this step, discharge the decommissioned battery to the cut-off voltage according to the discharge mode set by the original manufacturer of the decommissioned battery.

In this step, the first set time period is the time for the battery voltage to be fully balanced, and batteries of different materials have different time for fully balancing.

(2) According to the charging method set by the original factory of the decommissioned battery, charge the decommissioned battery to the rated capacity of a preset percentage of the nominal capacity, measure the voltage of the decommissioned battery at this time, and record it as the second voltage. The second voltage can reflect the voltage and capacity of the battery.

In this step, the rated capacity can be in the range of 20% to 35% of the nominal capacity.

(3) Put the decommissioned battery charged into the rated capacity at room temperature for the second set time, measure the voltage of the decommissioned battery at this time, and record it as the third voltage. The third voltage can reflect the self-discharge and AC internal resistance of the battery.

In this step, the second set time period is the time for the battery voltage to be fully balanced, and batteries of different materials have different time for fully balancing.

(4) Set the first judgment condition according to the first voltage, set the second judgment condition according to the second voltage, and set the third judgment condition according to the third voltage. According to the first judgment condition, the second judgment condition, and the third judgment condition in sequence The retired battery is judged, and the above judgment steps are completed for several retired batteries to form a first preselected group, a second preselected group and a third preselected group.

In this step, referring to Table 1, taking 22 batteries as an example, specifically, the first voltage, the second voltage, and the third voltage of each retired battery are counted.

The first voltage difference, the second voltage difference, and the third voltage difference of each retired battery relative to the first retired battery are counted.

Set a first threshold, a second threshold, and a third threshold. The first threshold is the voltage difference threshold of the first voltage, the second threshold is the voltage difference threshold of the second voltage, and the third threshold is the voltage difference threshold of the third voltage. Assume that the first threshold ≤ 50 mV, the second threshold ≤ 50 mV, and the third threshold ≤ 30 mV.

According to the voltage difference threshold of the first voltage, the retired batteries are sorted and counted to form a first preselected group, and batteries 1 to 6 are the first preselected group.

According to the voltage difference threshold of the second voltage, the retired batteries are sorted and counted to form a second preselected group, and batteries 1 to 6 are the second preselected group.

According to the voltage difference threshold of the third voltage, the retired batteries are sorted and counted to form a third preselected group, and batteries 1 to 8 are the third preselected group.

(5) Select the retired batteries that are selected into the first preselection group, the second preselection group, and the third preselection group at the same time as one group, and the 1~6 batteries are the first group.

Adjust the first judgment condition, the second judgment condition, and the third judgment condition to group all the decommissioned batteries to obtain several decommissioned battery packs.

Adjust the first threshold ≤ 100 millivolts, the second threshold ≤ 100 millivolts, and the third threshold ≤ 60 millivolts, then the 7~11 batteries are the second group, and so on, all batteries can be divided into several battery packs , The electrical performance of the batteries in each battery pack is similar.

Retired batteries are sorted according to the first threshold, second threshold, and third threshold, which realizes the purpose of screening and reorganizing retired batteries according to the four key control points of internal resistance, voltage, capacity, and self-discharge.

The following provides a repair method for retired batteries, the steps are as follows:

(1) Select one or more retired batteries from each retired battery pack, and detect the actual capacity of the selected retired batteries.

Since the electrical properties of the batteries in each battery pack are similar, the actual capacity of the selected decommissioned battery may represent the actual capacity of the group of decommissioned batteries. Preferably, 2 to 5 decommissioned batteries are selected from each decommissioned battery group.

(2) Detect the actual capacity of the selected decommissioned batteries, and screen out repairable decommissioned battery packs.

Preferably, a retired battery whose actual capacity is 60%-80% of the nominal capacity is selected for repair, and the actual capacity of the selected retired battery is 60%. %~80% of the nominal capacity, the decommissioned battery pack where the selected decommissioned battery is located is a repairable decommissioned battery pack.

Take the lithium iron phosphate electric bus battery as an example, the nominal capacity is 150Ah, and the selected decommissioned battery whose actual capacity is in the range of 90Ah-120Ah is a repairable decommissioned battery.

In this embodiment, the above-mentioned actual capacity detection method is: according to a certain constant current value of the decommissioned battery, specifically, the constant current value can be 0.2C of the nominal capacity, charge and discharge cycle 1 time, record its discharge capacity , Is the actual capacity.

(3) Calculate the weight of electrolyte that needs to be injected into each retired battery in each repairable retired battery pack, specifically: calculate the maximum capacity loss of the selected retired battery, the maximum capacity loss is the nominal capacity and the actual capacity The difference is calculated based on the maximum capacity loss to calculate the lost power, and then calculate the quality of electrolyte that needs to be replenished for each decommissioned battery in the set of repairable decommissioned battery packs, specifically, from a repairable decommissioned battery pack The actual capacity of the decommissioned battery selected in the selection is 90Ah and 100Ah, the nominal capacity is 150Ah, the capacity loss is 60Ah and 50Ah respectively, and the maximum capacity loss is 60Ah, then each decommissioned battery in the repairable decommissioned battery pack needs The mass of the supplemented electrolyte is 75g.

(4) Discharge each decommissioned battery in each repairable decommissioned battery pack to its cut-off voltage to fully discharge. The internal environment of the battery, including electrolyte, positive and negative plates, separators, etc., is isolated from the external environment. When the battery is charged, the negative lithium material is very active and easily reacts with water and oxygen in the air to release heat , The heat can make the electrolyte at high temperature, and the high temperature will cause other negative chain reactions, or even thermal runaway. Therefore, the battery needs to be fully discharged to ensure the safety of the battery.

Specifically, a certain constant current value is used to discharge to the cut-off voltage. The cut-off voltage refers to a very low voltage range. Different batteries have different cut-off voltage values in the standard.

(5) Inject the electrolyte. Preferably, the electrolyte is injected under a vacuum condition to prevent air from reacting with the electrolyte and prevent air from affecting the electrolyte. The specific method of injecting electrolyte into the decommissioned battery is as follows: remove the upper cover of the decommissioned battery, cut off part of the protective rubber on the battery cover to form a rubber hole in an environment where the dew point temperature is less than or equal to -35℃, and use a drill Align the rubber hole and drill through the battery cover, and then use the liquid injection nozzle to align the rubber hole to start vacuuming. After the vacuum is completed, start to inject the electrolyte. Preferably, the electrolyte is injected in multiple times, each time the electrolyte is injected Before vacuuming. Preferably, the vacuum degree of the vacuum condition is less than or equal to -0.085 MPa.

In this embodiment, 75 g of electrolyte is injected into each decommissioned battery in a group of decommissioned battery packs. The electrolyte is injected in 3 times, first vacuumize to -0.085MPa, inject 1/3 of the electrolyte to be injected, or 25g; then vacuum to -0.085MPa, inject 1/3 of the electrolyte to be injected, or 25g; and finally Then vacuumize to -0.085MPa, and inject 1/3 of the electrolyte to be injected, that is, 25g.

After the electrolyte injection is completed, the sealing is carried out. Each decommissioned battery in the same group is injected with the same weight of electrolyte.

(6) Charge and discharge the decommissioned batteries injected with electrolyte. The method of charging and discharging activation is as follows: let the retired battery injected with electrolyte stand still, make the electrolyte fully infiltrate the inside of the battery, charge to the upper limit of battery voltage with a first constant current, and then discharge to the battery cut-off voltage with a second constant current. Since the battery has been fully discharged before the electrolyte is injected, the charging current should be as small as possible in order to better repair the SEI film during charging. Preferably, the first constant current is 0.01 C~0.1 C of the nominal capacity of the decommissioned battery . When discharging, in order to speed up the discharge, a larger constant current can be used for discharging. Preferably, the second constant current is 0.5 C~1 C of the nominal capacity of the decommissioned battery. Since the electrolyte inside the battery flows faster at high temperatures, it is easy to place the battery in a high temperature environment to allow the injected electrolyte to quickly infiltrate the inside of the battery. However, if the temperature is too high, the internal reaction of the battery will increase. , For example, the SEI film is easy to decompose at high temperature. Therefore, to balance the above two aspects, preferably, the decommissioned battery injected with electrolyte is allowed to stand for 1 to 5 days at 35°C to 50°C. In this embodiment, after each decommissioned battery is injected with electrolyte and placed at 45 degrees for 3 days, the nominal capacity of 0.05C is charged to 3.45V, and the nominal capacity of 0.5C is discharged to 2V for activation.

Taking the decommissioned LiFePO4/graphite single battery as an example, the discharge curve comparison chart before and after refilling electrolyte repair and activation is shown in Fig. 2. Curve B in Fig. 2 is the discharge curve of the retired battery after the repair of the present invention , Curve A is the discharge curve of the decommissioned battery before repair. It can be seen from Fig. 2 that the capacity of the decommissioned LiFePO4/graphite single cell after being repaired by the method of the present invention is significantly improved compared to before being repaired.

(7) Group the decommissioned batteries after activation in step (6) to form a battery pack to further optimize the performance of the battery pack, which specifically includes the following steps:

1. Detect the discharge capacity and charge transfer impedance of the decommissioned battery after activation. In this specific embodiment, the nominal capacity of 1C constant current charging and constant current discharge to the upper and lower limit voltages are used to record the discharge capacity and DC internal resistance of each decommissioned battery; the electrochemical workstation tests the AC internal resistance and frequency of each decommissioned battery The range is 1000HZ-0.01HZ, and the charge transfer impedance is calculated using ZView2 simulation software.

Among them, the discharge capacity C, DC internal resistance DC-IR, and charge transfer resistance RCt of the 20 batteries repaired and activated by electrolyte injection are shown in Table 2.

2. Classify the activated decommissioned batteries according to their discharge capacity. Specifically, the discharge capacity is divided into different bins with the set capacity difference as an interval, and the activated decommissioned battery is binned according to the bins where the discharge capacity is located. Preferably, the capacity difference is 0~5% of the nominal capacity of the decommissioned battery. In this specific embodiment, the above-mentioned 20 batteries are classified according to a capacity difference of 10 Ah, and No. 1-4, No. 5-15, and No. 16-20 are respectively of the same grade.

3. Retired batteries in the same file are grouped according to charge transfer impedance. Specifically, the charge transfer impedance of the decommissioned battery is divided into different grouping intervals with the set charge transfer impedance difference as an interval, and the activated decommissioned batteries are grouped according to the grouping interval in which the charge transfer impedance of the decommissioned battery is located. Preferably, the charge transfer impedance difference is 10%-15% of the average value of the charge transfer impedance of the decommissioned batteries after activation in the same gear. In this specific embodiment, in the same battery, such as AA batteries, the average value of the charge transfer impedance of the battery is 0.3814, and 13% of the average value, that is, 0.05, is used as the charge transfer impedance difference, that is, press If the charge transfer impedance difference ΔRCt=0.05 is grouped, the charge transfer impedance is between 0.35 and 0.4 for one group, and the charge transfer impedance is between 0.4 and 0.45 for another group, then 6,7,8,9,10, The charge transfer resistance of No. 12, 14, and No. 15 batteries is between 0.35 and 0.4, divided into a group, and the charge transfer resistance of No. 5 and No. 11 batteries is between 0.35 and 0.4, which are left. In the same way, in the bins of No. 1 to 4, the No. 1 battery is left, and in the bins of No. 16 to 20, the No. 16 battery is left.

4. After the grouping of the retired batteries in each gear is completed, the remaining retired batteries in each gear are re-classified and grouped according to the above method.

In this specific embodiment, the maximum battery capacity difference between the remaining No. 5 and No. 11 batteries and No. 2, 3, and No. 4 batteries is less than the capacity difference standard of 10Ah. ,3,4 batteries, the maximum charge transfer impedance difference is 0.043, which is less than the charge transfer impedance difference standard ΔRCt=0.05, therefore, 5,11 batteries and 2,3,4 batteries are divided into a group. The grouping method of other batteries is the same as the above method.

5. The retired batteries divided into the same group form a battery pack.

Choose 4 batteries from the 6,7,8,9,10,12,14,15 batteries grouped in series and parallel to form battery group B; it will be the same as the capacity of the 4 batteries in battery group B , The series and parallel combination of No. 1, 2, 3, 4 batteries with similar DC internal resistance form battery group A. The cycle performance test is performed on battery pack A and battery pack B at room temperature. The cycle performance test comparison chart is shown in Fig. 3, and curve B in Fig. 3 is the cycle performance of battery pack B selected by the grouping method of the present invention Curve, curve A is the cycle performance curve of battery pack A selected by traditional pass capacity and DC internal resistance. It can be seen from FIG. 3 that the battery pack B selected by the battery grouping method of the present invention is better than the battery pack A selected by the traditional pass capacity and DC internal resistance in terms of cycle performance. The battery pack obtained by the battery grouping method of the present invention has better consistency.

Claims

A fast grouping method for retired batteries is characterized in that it comprises the following steps:

The decommissioned battery discharged to the cut-off voltage is allowed to stand for a first set period of time at room temperature, and the voltage of the decommissioned battery at this time is measured and recorded as the first voltage;

Charge the decommissioned battery to a rated capacity that is a preset percentage of the nominal capacity according to the original charging method of the decommissioned battery, measure the voltage of the decommissioned battery at this time, and record it as the second voltage;

Standing the retired battery charged with the rated capacity for a second set period of time at room temperature, measuring the voltage of the retired battery at this time, and recording it as the third voltage;

A first judgment condition is set according to the first voltage, a second judgment condition is set according to the second voltage, a third judgment condition is set according to the third voltage, and a third judgment condition is set according to the first judgment condition, the second judgment condition, and the first judgment condition. 3. Judgment conditions sequentially judge the retired batteries;

Complete the above judgment steps for a number of retired batteries to form a first preselected group, a second preselected group, and a third preselected group; and

The retired batteries that are simultaneously selected into the first preselected group, the second preselected group, and the third preselected group are divided into one group.
The method for rapid sorting of retired batteries according to claim 1, wherein the rated capacity is in the range of 20% to 35% of the nominal capacity.
The method for rapid sorting of retired batteries according to any one of claims 1 to 2, wherein a first threshold, a second threshold, and a third threshold are set, and the first threshold is the voltage of the first voltage A difference threshold, the second threshold is a voltage difference threshold of the second voltage, and the third threshold is a voltage difference threshold of the third voltage.
The method for rapidly sorting retired batteries according to claim 3, wherein the step of sequentially judging the retired batteries according to the first judgment condition, the second judgment condition, and the third judgment condition comprises:

Count the first voltage, second voltage, and third voltage of each retired battery;

Count the first voltage difference and the second voltage difference of each retired battery relative to the first retired battery as the third voltage difference;

Sorting and counting retired batteries according to the voltage difference threshold of the first voltage to form the first preselected group;

Sorting and counting retired batteries according to the voltage difference threshold of the second voltage to form the second preselected group;

According to the voltage difference threshold of the third voltage, the retired batteries are sorted and counted to form the third preselected group.
A method for repairing a decommissioned battery, which is characterized in that it includes the following steps:

The decommissioned battery discharged to the cut-off voltage is allowed to stand for a first set period of time at room temperature, and the voltage of the decommissioned battery at this time is measured and recorded as the first voltage;

Charge the decommissioned battery to a rated capacity that is a preset percentage of the nominal capacity according to the original charging method of the decommissioned battery, measure the voltage of the decommissioned battery at this time, and record it as the second voltage;

Standing the retired battery charged with the rated capacity for a second set period of time at room temperature, measuring the voltage of the retired battery at this time, and recording it as the third voltage;

A first judgment condition is set according to the first voltage, a second judgment condition is set according to the second voltage, a third judgment condition is set according to the third voltage, and a third judgment condition is set according to the first judgment condition, the second judgment condition, and the first judgment condition. 3. Judgment conditions sequentially judge the retired batteries;

Complete the above judgment steps for a number of retired batteries to form a first preselected group, a second preselected group, and a third preselected group;

Dividing the retired batteries that are simultaneously selected into the first preselection group, the second preselection group, and the third preselection group into one group;

Adjusting the first judgment condition, the second judgment condition, and the third judgment condition, and group all retired batteries to obtain a number of retired battery packs;

Select one or more retired batteries from each of the retired battery packs, and detect the actual capacity of the selected retired batteries;

According to the actual capacity of the selected decommissioned batteries, select repairable decommissioned battery packs;

Discharging each decommissioned battery in each repairable decommissioned battery pack to its cut-off voltage;

Inject the decommissioned batteries in each of the repairable decommissioned battery packs with a corresponding weight of electrolyte, and then seal; wherein, each decommissioned battery in the repairable decommissioned battery packs is injected with the same weight of the electrolyte; as well as

The decommissioned battery injected with the electrolyte is charged and discharged for activation.
The method for rapid sorting of retired batteries according to claim 5, wherein the rated capacity is in the range of 20% to 35% of the nominal capacity.
The method for rapid sorting of retired batteries according to any one of claims 5 to 6, wherein a first threshold, a second threshold, and a third threshold are set, and the first threshold is the voltage of the first voltage. A difference threshold, the second threshold is a voltage difference threshold of the second voltage, and the third threshold is a voltage difference threshold of the third voltage.
The method for rapid sorting of retired batteries according to claim 7, wherein the step of sequentially judging the retired batteries according to the first judgment condition, the second judgment condition, and the third judgment condition comprises:

Count the first voltage, second voltage, and third voltage of each retired battery;

Count the first voltage difference and the second voltage difference of each retired battery relative to the first retired battery as the third voltage difference;

Sorting and counting retired batteries according to the voltage difference threshold of the first voltage to form the first preselected group;

Sorting and counting retired batteries according to the voltage difference threshold of the second voltage to form the second preselected group;

According to the voltage difference threshold of the third voltage, the retired batteries are sorted and counted to form the third preselected group.
The method for repairing a decommissioned battery according to claim 5, wherein when the actual capacity of the selected decommissioned battery is 60% to 80% of the nominal capacity, the decommissioned battery pack in which the selected decommissioned battery is located is Repairable decommissioned battery pack.
The method for repairing a decommissioned battery according to claim 5, wherein the method of charging and discharging activation is: standing the decommissioned battery injected with the electrolyte solution so that the electrolyte solution fully infiltrates the inside of the battery, Use the first constant current to charge to its upper voltage limit, and then use the second constant current to discharge to its cut-off voltage.
The method for repairing a decommissioned battery according to claim 10, wherein the first constant current is 0.01 C to 0.1 C of the nominal capacity of the decommissioned battery; and the second constant current is the decommissioned battery 0.5 C~1 C of the nominal capacity.
The method for repairing a decommissioned battery according to claim 10, wherein the step of leaving the decommissioned battery injected with the electrolyte solution is: placing the repairable decommissioned battery injected with the electrolyte solution at 35 Let stand for 1 to 5 days under the condition of ℃~50℃.
The method for repairing retired batteries according to claim 5, further comprising the step of grouping the retired batteries after activation to form a battery pack, comprising:

Detecting the discharge capacity and charge transfer resistance of the decommissioned battery after activation;

Classify the activated decommissioned batteries according to the discharge capacity;

The activated decommissioned batteries in the same file are grouped according to the charge transfer impedance;

The activated decommissioned batteries divided into the same group constitute a battery pack.
The method for repairing a decommissioned battery according to claim 13, wherein the method of classifying the activated decommissioned battery according to the discharge capacity is: dividing the discharge capacity at intervals of a set capacity difference Into different bins, and bin the activated decommissioned batteries according to the bins where the discharge capacity is located.
The method for repairing a decommissioned battery according to claim 14, wherein the capacity difference is 0 to 5% of the nominal capacity of the decommissioning battery.
The method for repairing decommissioned batteries according to claim 13, wherein the method for grouping the activated decommissioned batteries in the same file according to the charge transfer impedance is: using a set charge transfer impedance The difference is an interval, the charge transfer impedance is divided into different grouping intervals, and the activated decommissioned batteries are grouped according to the grouping interval in which the charge transfer impedance is located.
The method for repairing a decommissioned battery according to claim 13, wherein the charge transfer impedance difference is 10% to 15% of the average value of the charge transfer impedance of the activated decommissioned battery in the same file.
The method for repairing a decommissioned battery according to claim 5, wherein the method of injecting the electrolyte is: removing the upper cover of the repairable decommissioned battery, and in an environment where the dew point temperature is less than or equal to -35°C Next, cut off part of the protective rubber on the battery cover to form a rubber hole, align the rubber hole and drill through the battery cover, then use a liquid injection nozzle to align the rubber hole to start vacuuming, and then inject the electrolyte after the vacuum is completed .
The method for repairing a decommissioned battery according to claim 5, wherein the detection method of the actual capacity is: charging and discharging the decommissioned battery with a constant current cycle once, and recording the discharge capacity, which is the actual capacity.
The method for repairing decommissioned batteries according to claim 5, wherein the method for calculating the weight of the electrolyte injected into each decommissioned battery in each repairable decommissioned battery pack is: calculating the selected For the maximum capacity loss of the decommissioned battery, the quality of the electrolyte that needs to be replenished for each decommissioned battery in the repairable decommissioned battery pack is calculated.