JP7076495B2 - How to quickly group and repair used batteries - Google Patents

Description

The present application relates to the technical field of lithium ion battery repair, and in particular to the rapid grouping and repair methods of used batteries.

Electric vehicles have become widespread for several years, and along with this, a large number of lithium-ion batteries with reduced performance and insufficient capacity due to long-term use have been generated.

The loss of battery capacity is mainly due to the loss of lithium ions and the increase in impedance due to side reactions due to the consumption of electrolytes.

The lost lithium ions mainly include lithium consumed to form an SEI film in the battery chemical conversion process, lithium consumed as a side reaction of the electrolytic solution, lithium dendrite produced by lithium in the negative electrode, and active lithium ions. Includes lithium loss due to loss of lithium ion acceptance due to structural changes in the material. These irreversible capacity losses caused by the loss of lithium are irreparable.

The electrolytic solution is a medium in which lithium ions are conducted between the positive and negative electrodes. In the charge / discharge process, the electrolytic solution reacts with the tab and the electrolytic solution is lost, and the concentration polarization resistance and charge transfer resistance generated by this are the capacity of the battery. It affects the deterioration and can repair the capacity of the lithium battery by replenishing the electrolyte.

In the prior art, the used battery is first fully charged and fully discharged to obtain the capacity parameter of the used battery, the repairable used battery is selected based on the capacity, and then the repairable used battery is selected. Is graded and filled with the weight of the electrolyte corresponding to the used battery of each grade. The method requires that all used batteries be fully charged, but charging and discharging all used batteries consumes a large amount of power.

An object of the present invention is to provide a method for rapid grouping and repair of used batteries, which can save power consumption and reduce production costs.

In order to realize the above object, the technical solution of the present invention is as follows.

A quick way to group used batteries is
A step of allowing the used battery discharged to the cutoff voltage to stand at room temperature for the first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
According to the charging method set for the primary battery of the used battery, the used battery is charged to a rated capacity of a predetermined percentage of the nominal capacity, and the voltage of the used battery at that time is measured and recorded as a second voltage. Steps to do and
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
Includes a step of grouping used batteries simultaneously selected within the first preselection set, the second preselection set and the third preselection set.

How to repair used batteries
A step of allowing a used battery discharged to the cutoff voltage to stand at room temperature for a first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
According to the charging method set for the primary battery of the used battery, the used battery is charged to a rated capacity of a predetermined percentage of the nominal capacity, and the voltage of the used battery at that time is measured to obtain a second voltage. And the steps to record as
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
A step of grouping used batteries simultaneously selected in the first preliminary selection group, the second preliminary selection group, and the third preliminary selection group, and
A step of adjusting the first determination condition, the second determination condition, and the third determination condition to group all used batteries to obtain a plurality of used assembled batteries.
A step of selecting one or more used batteries from each of the used assembled batteries and detecting the actual capacity of the selected used batteries, and
A step of selecting a repairable used battery pack based on the capacity of the selected used battery, and
A step of discharging each used battery in each of the repairable used battery sets to its cutoff voltage,
The electrolyte of the weight corresponding to each used battery in each repairable used battery is injected and sealed, but the same weight of the said battery in each used battery in the repairable used battery. The step of injecting the electrolyte and
A step of activating the charge / discharge of the used battery into which the electrolytic solution is injected is included.

Implementing the examples of this application has the following beneficial effects:

In the present invention, first, all used batteries are quickly grouped by acquiring three key voltage values that can characterize the battery performance so as not to fully charge and completely discharge the battery, and by setting judgment conditions. The same set of used batteries have similar electrical performance, shortening test time and saving power consumption.

Since the electrical performance of the same set of used batteries is similar, one or more batteries in each set of used batteries are selected to be fully charged and fully discharged, their capacity is measured, and the capacity is measured. The capacity can represent the capacity level of the same set of used batteries, select the repairable used set batteries based on the measured capacity, and then each set based on the measured capacity. Inject the corresponding weight of electrolyte for the repairable used battery to bring the used battery back to working battery level. Since only one or more batteries in each set are fully charged and fully discharged, the number of fully charged batteries is significantly reduced, and thus power consumption is significantly reduced to save production costs.

In the present invention, since the electrolytic solution inside the repaired battery is different from that of a new battery, the repaired used battery is re-sorted from both the battery capacity and the charge transfer resistance of the battery and grouped to obtain the capacity and the inside. It is more consistent than sorting by resistance and improves the recyclability of assembled batteries.

The rapid grouping and repair methods of the present invention are more suitable for batch repair and automation operations and improve production efficiency.

In order to more clearly explain the examples of the present application or the technical solutions in the prior art, the drawings used in the description of the examples or the prior art are briefly introduced below and as will be apparent from the following description. , Drawings are some embodiments of the present application, and one of ordinary skill in the art can obtain other drawings according to these drawings without any creative effort.

It is a change relationship diagram of voltage and capacity at the time of normal charge / discharge of a lithium battery. In one embodiment of the present invention, it is a comparative figure of the discharge curve before and after the electrolytic solution replenishment and activation for the LiFePO ₄ / graphite used battery which has a nominal capacity of 150Ah. In one embodiment of the present invention, it is a room temperature cycle characteristic comparison diagram of two assembled batteries obtained by using different grouping methods.

Hereinafter, the technical solutions in the examples of the present application will be described clearly and completely with reference to the drawings in the examples of the present application, but the examples described will be part of the examples of the present application. It is clear that it is not all examples. Based on the examples of this application, all other examples obtained by those skilled in the art without creative effort shall be within the scope of protection of this application.

In the present invention, a battery whose capacity has decreased due to loss of an electrolytic solution is repaired to the level of an operating battery, sorted again, paired again, continuously used in a power cell vehicle, and recycled.

Regarding how to select a repairable battery from used batteries, in the conventional technology, usually, after the battery is fully charged, it is left at room temperature for 5 days or more to detect the voltage, and the voltage drop and the actual capacity data are acquired. After that, the battery is discharged to the cutoff voltage at a constant current to obtain the actual capacity of the battery, and such a sorting method consumes a long time and entails a large consumption of power resources due to a full charge. The four parameters of internal resistance, voltage, capacity, and self-discharge rate, which reflect battery consistency, are important control points for battery selection. As shown in FIG. 1, it is a charge / discharge curve of a lithium battery having a voltage on the vertical axis and a charge / discharge integrated capacity on the horizontal axis. That is, the integrated value of the charge or discharge capacity over time during charging or discharging can be regarded as a change over time in the cell voltage during charging or discharging by substituting time on the horizontal axis. The voltage and capacitance values have been found to have a one-to-one correspondence in a single charging or discharging process, which is also the basis for the present invention to characterize capacitance in voltage.

In this embodiment, the battery is filled by detecting the critical voltage parameter of each battery and setting a plurality of judgment conditions regarding four parameters of internal resistance, voltage, capacity, and self-discharge that reflect the consistency of the battery. By obtaining a feature amount that can react to the difference in each battery capacity and voltage without charging and completely discharging, the performance and consistency of the recombinant battery are improved, the test time is shortened, and the test energy consumption is reduced.

The rapid selection method for lithium batteries in this embodiment targets used batteries of the same model and batch of the same manufacturer. Certain voltage conditions are associated with other performance parameters of the battery, assuming used batteries of the same model and batch. Since the correlation of performance parameters differs depending on the battery model, and the outer shape of the battery of a different model also differs, recombination between used batteries of different models and different batches is not performed.

The method of rapid grouping of used batteries provided in the present invention does not fully charge and fully discharge the batteries, shortens the sorting time, improves the sorting efficiency, saves power, and steps (1) to Including step (5).

(1) The used battery discharged to the cutoff voltage is allowed to stand at room temperature for the first set time, the voltage of the used battery at that time is measured, and recorded as the first voltage that can reflect the polarization internal resistance of the battery. ..

In this step, the used battery is discharged to the cutoff voltage according to the charging method set for the primary battery of the used battery.

In this step, the first set time is the time when the battery voltage can be sufficiently balanced, and the time when the battery with different materials can be sufficiently balanced is different.

(2) According to the charging method set for the primary battery of the used battery, the used battery is charged to the rated capacity of a predetermined percentage of the nominal capacity, the voltage of the used battery at that time is measured, and the voltage and capacity of the battery are measured. Record as a second voltage that can be reflected.

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

(3) A used battery charged to the rated capacity is allowed to stand at room temperature for a second set time, the voltage of the used battery at that time is measured, and a third voltage that can reflect the self-discharge and AC internal resistance of the battery. Record as.

In this step, the second set time is the time when the battery voltage can be sufficiently balanced, and the time when the battery with different materials can be sufficiently balanced is different.

(4) The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , The used batteries are sequentially determined based on the first determination condition, the second determination condition, and the third determination condition, the above determination steps are completed for the plurality of used batteries, and the first preliminary selection set. , A second preliminary selection set and a third preliminary selection group are formed.

In this step, as shown in Table 1, using 22 batteries as an example, specifically, the first voltage, the second voltage, and the third voltage of each used battery are statistic.

The first voltage difference, the second voltage difference, and the third voltage difference of each used battery with respect to the first used battery are statistic.

A first threshold, a second threshold and a third threshold are set, 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 so on. The third threshold is the voltage difference threshold of the third voltage. It is assumed that the first threshold is ≤50 millivolts, the second threshold is ≤50 millivolts, and the third threshold is ≤30 millivolts.

Used batteries statistic based on the voltage difference threshold of the first voltage are selected to form the first preselection set, and the batteries numbered 1 to 6 are the first preselection set.

Used batteries statistic based on the voltage difference threshold of the second voltage are selected to form a second preselection set, and the batteries numbered 1 to 6 are the second preselection set.

Used batteries statistic based on the voltage difference threshold of the third voltage are selected to form a third preselection set, and the batteries numbered 1 to 8 are the third preselection set.

(5) Used batteries simultaneously selected in the first preliminary selection group, the second preliminary selection group, and the third preliminary selection group are grouped, and therefore the batteries numbered 1 to 6 are the first group. ..

The first determination condition, the second determination condition, and the third determination condition are adjusted, and all the used batteries are grouped to obtain a plurality of used assembled batteries.

Adjust so that the first threshold is ≤100 millivolts, the second threshold is ≤100 millivolts, and the third threshold is ≤60 millivolts, so the batteries numbered 7-11 are in the second set. By analogy, all batteries can be divided into a plurality of assembled batteries, and the electrical performance of the batteries in each assembled battery is similar.

Sorting is performed on the used battery based on the first threshold value, the second threshold value, and the third threshold value, that is, the used battery has four key control points of internal resistance, voltage, capacity, and self-discharge. Achieve the purpose of sorting and recombining based on.

Hereinafter, a method for repairing a used battery is provided, and steps (1) to (7) are included.

(1) One or more used batteries are selected from each used assembled battery, and the actual capacity of the selected used battery is detected.

Since the electrical performance of the batteries in each assembled battery is close, the actual capacity of the selected used battery can represent the actual capacity of the used assembled battery, preferably 2 to 2 to 2 from each used assembled battery. Select 5 used batteries.

(2) The actual capacity of the selected used battery is detected, and the used battery set that can be repaired is selected.

Preferably, when a used battery having a capacity of 60% to 80% of the nominal capacity is selected and repaired, the capacity of the selected used battery is 60% to 80% of the nominal capacity. , The used assembled battery in which the selected used battery is present is a repairable used assembled battery.

Taking the lithium iron phosphate electric bus cell as an example, a used battery whose nominal capacity is 150 Ah and whose actual capacity of the selected used battery is in the range of 90 Ah to 120 Ah is a repairable used battery. Is.

In this embodiment, the method of detecting the actual capacity is to set the used battery to a certain constant current value, specifically, the constant current value to 0.2 C of the nominal capacity, and perform one charge / discharge cycle. The discharge capacity is recorded as the actual capacity.

(3) Calculate the weight of the electrolyte to be injected by each used battery in each repairable used battery, specifically, calculate the maximum capacity loss amount of the selected used battery, and maximum. The capacity loss amount is the difference between the nominal capacity and the actual capacity, the amount of electricity lost is calculated based on the maximum capacity loss amount, and each used battery in the repairable used battery set is replenished. The mass of the electrolytic solution to be calculated is calculated, and specifically, the actual capacity of the used battery selected from a certain repairable used battery is 90Ah and 100Ah, the nominal capacity is 150Ah, and the capacity loss amount. Are 60 Ah and 50 Ah, respectively, and the maximum capacity loss amount is 60 Ah, so that the mass of the electrolyte to be replenished by each used battery in the set of repairable used batteries is 75 g.

(4) In order to sufficiently discharge, each used battery in each repairable used assembled battery is discharged to the cutoff voltage. The internal environment of the battery contains electrolytes, positive and negative electrode sheets, separators, etc. and is shielded from the external environment, but when the battery is charged, the negative electrode lithium material is very active and contains moisture in the air. It easily reacts with oxygen and releases heat. The heat causes the electrolyte to heat up, which can lead to other negative chain reactions or thermal runaway, so the battery must be fully discharged to ensure battery safety.

Specifically, it discharges to the cutoff voltage at a certain constant current value. The cutoff voltage refers to a very low voltage range, and the standard cutoff voltage value varies depending on the battery.

(5) The electrolytic solution is injected, preferably, the electrolytic solution is injected under vacuum conditions in order to prevent the air from reacting with the electrolytic solution and to prevent the air from affecting the electrolytic solution. Specifically, the method of injecting the electrolytic solution into the used battery is to remove the upper lid of the used battery and cut a part of the protective adhesive of the battery lid plate in an environment where the dew point temperature is -35 ° C or lower. To form a coated hole of the adhesive, pierce the battery lid plate with a drill to match the coated hole of the adhesive, and then start vacuuming to match the coated hole of the adhesive using a liquid injection nozzle. After the vacuuming is completed, the electrolytic solution is injected, preferably, the electrolytic solution is injected in a plurality of times, and vacuum suction is performed before injecting the electrolytic solution. Preferably, the degree of vacuum is −0.085 MPa or less.

In this embodiment, 75 g of the electrolytic solution is injected into each used battery in one set of used batteries. The electrolytic solution is injected in 3 portions, first evacuated to -0.085 MPa, 1/3 of the electrolytic solution to be injected, that is, 25 g is injected, and then vacuumed again to -0.085 MPa. Inject 1/3 of the electrolytic solution to be injected, that is, 25 g, and finally perform vacuum suction again to −0.085 MPa, and inject 1/3 of the electrolytic solution to be injected, that is, 25 g.

Seal after the injection of the electrolyte is completed. Inject the same weight of electrolyte into each used battery in the same set.

(6) Charge / discharge activation of each used battery into which the electrolytic solution is injected is performed. The method of charge / discharge activation is as follows: the used battery in which the electrolytic solution is injected is allowed to stand still, the electrolytic solution is sufficiently permeated into the battery, the battery is charged to the upper limit of the battery voltage with the first constant current, and then the second is performed. It is to discharge to the cutoff voltage of the battery with a constant current of 2. When the battery is fully discharged and charged before injecting the electrolyte, the charging current should be as low as possible in order to better repair the SEI membrane, the first constant current is the nominal capacity of the used battery. It is preferably 0.01C to 0.1C. When discharging, in order to increase the speed, a relatively large constant current may be used for discharging, and the second constant current is preferably 0.5 C to 1 C, which is the nominal capacity of the used 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 penetrate inside the battery, but if the temperature is too high, it will be inside the battery. Since the reaction of the SEI film becomes violent and the SEI film may be easily decomposed at high temperature, it may have a negative effect. It is preferable to allow it to stand for 1 to 5 days under the condition of ° C. In this embodiment, after injecting the electrolytic solution into each used battery, the battery is left at 45 degrees for 3 days, charged to 3.45 V at a nominal capacity of 0.05 C, and discharged to 2 V at a nominal capacity of 0.5 C. , Activate.

Taking a used LiFePO ₄ / graphite cell as an example, a comparison diagram of the discharge curves before and after restoration and activation by replenishment of an electrolytic solution is as shown in FIG. 2, and in FIG. 2, curve B is the use after restoration of the present invention. It is a discharge curve of the used battery, and the curve A is a discharge curve of the used battery before repair. As can be seen from FIG. 2, the capacity of the used LiFePO ₄ / graphite cell repaired by the method of the present invention is significantly improved as compared with that before the repair.

(7) Each used battery activated by step (6) is grouped to form an assembled battery, and the performance of the assembled battery is further optimized, specifically including the following steps.

1. 1. Detects the discharge capacity and charge transfer resistance of the used battery after activation. In this specific embodiment, the battery is charged and discharged with a constant current up to the upper and lower voltage at a nominal capacity of 1C, the discharge capacity of each used battery and the DC internal resistance are recorded, and the electrochemical station is inside the AC of each used battery. The resistance is measured, the frequency range is 1000HZ to 0.01HZ, and the charge transfer resistance is calculated by fitting with ZView2 simulation software.

However, Table 2 shows information on the discharge capacity C, DC internal resistance DC-IR, and charge transfer resistance RCt of the 20 batteries after repair and activation by injecting an electrolytic solution.

2. 2. Grade activated used batteries according to their discharge capacity. Specifically, the discharge capacity is divided into different grade sections with the set capacity difference as an interval, and the activated used battery is graded according to the grade section in which the discharge capacity exists. The capacity difference is preferably 0 to 5% of the nominal capacity of the used battery. In this specific embodiment, the above 20 batteries are graded with a capacity difference of 10 Ah, and the numbers 1 to 4, the numbers 5 to 15, and the numbers 16 to 20 are of the same grade, respectively.

3. 3. Group used batteries of the same grade based on charge transfer resistance. Specifically, the charge transfer resistance of the used battery is divided into different grouping sections with the set charge transfer resistance difference as an interval, and the activated used battery is a group in which the charge transfer resistance of the used battery exists. Group according to the section. Preferably, the charge transfer resistance difference is 10% to 15% of the average charge transfer resistance of the same grade of activated used battery. In this specific embodiment, among the batteries of the same grade, for example, among the batteries of the numbers 5 to 15, the average value of the charge transfer resistance of the battery of the grade is 0.3814, which is 13% of the average value. , That is, 0.05 is the charge transfer resistance difference, that is, when grouped according to the charge transfer resistance difference ΔRCt = 0.05, there is only one set in which the charge transfer resistance is between 0.35 and 0.4. , The charge transfer resistance is between 0.4 and 0.45 in the other set, so the charge transfer resistance of the batteries numbered 6, 7, 8, 9, 10, 12, 14, 15 is It is between 0.35 and 0.4 and is divided into one set, and the charge transfer resistance of the batteries of numbers 5 and 11 is between 0.4 and 0.45 and remains. Similarly, the number 1 battery remains in the number 1 to 4 grade sections, and the number 16 battery remains in the number 16 to 20 grade sections.

4. After the grouping of the used batteries of each grade is completed, the remaining used batteries of each grade are graded and grouped according to the above method.

In this specific embodiment, the maximum battery capacity difference between the remaining batteries Nos. 5 and 11 and the batteries Nos. 2, 3 and 4 is less than the standard capacity difference of 10 Ah, is again divided into the same grades, and The maximum charge transfer resistance difference between the batteries of numbers 5 and 11 and the batteries of numbers 2, 3 and 4 is 0.043, which is less than ΔRCt = 0.05, which is the standard of the charge transfer resistance difference, and therefore numbers 5 and 11. Batteries and batteries numbered 2, 3 and 4 are grouped into a set. The method for grouping other batteries is the same as the above method.

5. An assembled battery is composed of the used batteries divided into the same group.

Four batteries are selected from the batteries of numbers 6, 7, 8, 9, 10, 12, 14, and 15 divided into the same set and combined in series and in parallel to form the assembled battery B, and the assembled battery B is 4 The assembled battery A is formed by combining the batteries of numbers 1, 2, 3, and 4, which are close to the capacity of one battery and the internal resistance of DC, in series and in parallel. A circulation performance test was performed on the assembled battery A and the assembled battery B at room temperature, respectively, and a comparative diagram of the circulation performance test is as shown in FIG. 3. In FIG. 3, the curve B is selected by using the grouping method of the present invention. It is the circulation performance curve of the assembled battery B, and the curve A is the circulation performance curve of the assembled battery A selected by using the conventional passing capacity and the DC internal resistance. As can be seen from FIG. 3, the assembled battery B selected by using the battery grouping method of the present invention is superior in cycle characteristics to the assembled battery A selected by using the conventional passing capacity and DC internal resistance. There is. The assembled batteries obtained by the battery grouping method of the present invention have better consistency.

(Additional note)
(Appendix 1)
A step of allowing the used battery discharged to the cutoff voltage to stand at room temperature for the first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
According to the charging method set for the primary battery of the used battery, the used battery is charged to a rated capacity of a predetermined percentage of the nominal capacity, and the voltage of the used battery at that time is measured and recorded as a second voltage. Steps to do and
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
Rapid of used batteries comprising the steps of grouping used batteries simultaneously selected within the first preselection set, the second preselection set and the third preselection set. Grouping method.

(Appendix 2)
The rapid grouping method for used batteries according to Appendix 1, wherein the rated capacity is in the range of 20% to 35% of the nominal capacity.

(Appendix 3)
A first threshold value, a second threshold value and a third threshold value are set, the first threshold value is the voltage difference threshold value of the first voltage, and the second threshold value is the voltage difference of the second voltage. The method for rapidly grouping used batteries according to Appendix 1 or 2, wherein the third threshold value is a voltage difference threshold value of the third voltage.

(Appendix 4)
The step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition is
Statistics of the first voltage, the second voltage and the third voltage of each used battery,
Statistics of the first voltage difference, the second voltage difference, and the third voltage difference of each used battery with respect to the first used battery, and
By selecting the used batteries statistically based on the voltage difference threshold of the first voltage to form the first preliminary selection set,
By selecting the used batteries statistically based on the voltage difference threshold of the second voltage to form the second preliminary selection set,
The used battery according to Appendix 3, wherein the used battery statistic based on the voltage difference threshold of the third voltage is selected to form the third preliminary selection set, and the present invention includes. How to quickly group.

(Appendix 5)
A step of allowing the used battery discharged to the cutoff voltage to stand at room temperature for the first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
According to the charging method set for the primary battery of the used battery, the used battery is charged to a rated capacity of a predetermined percentage of the nominal capacity, and the voltage of the used battery at that time is measured and recorded as a second voltage. Steps to do and
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
A step of grouping used batteries simultaneously selected in the first preliminary selection group, the second preliminary selection group, and the third preliminary selection group, and
A step of adjusting the first determination condition, the second determination condition, and the third determination condition to group all used batteries to obtain a plurality of used assembled batteries.
A step of selecting one or more used batteries from each of the used assembled batteries and detecting the actual capacity of the selected used batteries, and
A step of selecting a repairable used battery pack based on the capacity of the selected used battery, and
A step of discharging each used battery in each of the repairable used batteries to its cutoff voltage,
The electrolyte of the weight corresponding to each used battery in each repairable used battery is injected and sealed, but the same weight of the said battery in each used battery in the repairable used battery. The step of injecting the electrolyte and
A method for repairing a used battery, which comprises a step of activating charging / discharging of the used battery into which the electrolytic solution is injected.

(Appendix 6)
The method for repairing a used battery according to Appendix 5, wherein the rated capacity is in the range of 20% to 35% of the nominal capacity.

(Appendix 7)
A first threshold value, a second threshold value and a third threshold value are set, the first threshold value is the voltage difference threshold value of the first voltage, and the second threshold value is the voltage difference of the second voltage. The method for repairing a used battery according to Appendix 5 or 6, wherein the third threshold value is a voltage difference threshold value of the third voltage.

(Appendix 8)
The step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition is
Statistics of the first voltage, the second voltage and the third voltage of each used battery,
Statistics of the first voltage difference, the second voltage difference, and the third voltage difference of each used battery with respect to the first used battery, and
By selecting the used batteries statistically based on the voltage difference threshold of the first voltage to form the first preliminary selection set,
By selecting the used batteries statistically based on the voltage difference threshold of the second voltage to form the second preliminary selection set,
The used battery according to Appendix 7, wherein the used battery statistically selected based on the voltage difference threshold value of the third voltage is selected to form the third preliminary selection set, and the present invention includes. How to repair.

(Appendix 9)
When the actual capacity of the selected used battery is a nominal capacity of 60% to 80%, the used assembled battery in which the selected used battery is present is a repairable used assembled battery. The method for repairing a used battery according to Appendix 5, which is a feature.

(Appendix 10)
The method of activating charge / discharge is
The used battery into which the electrolytic solution is injected is allowed to stand, the electrolytic solution is sufficiently permeated into the battery, charged to the upper limit of the voltage with the first constant current, and then with the second constant current. The method for repairing a used battery according to Appendix 5, wherein the battery is discharged to the cutoff voltage.

(Appendix 11)
The first constant current is 0.01C to 0.1C, which is the nominal capacity of the used battery, and the second constant current is 0.5C to 1C, which is the nominal capacity of the used battery. 10. The method for repairing a used battery according to Appendix 10.

(Appendix 12)
To allow the used battery infused with the electrolytic solution to stand means to allow the repairable used battery infused with the electrolytic solution to stand at 35 ° C to 50 ° C for 1 to 5 days. The method for repairing a used battery according to Appendix 10, which is characterized in that.

(Appendix 13)
The step further comprises the step of grouping the activated used batteries to form an assembled battery, wherein the step.
To detect the discharge capacity and charge transfer resistance of the activated used battery,
To grade the activated used battery according to the discharge capacity,
Grouping the activated used batteries within the same grade based on the charge transfer resistance, and
The method for repairing a used battery according to Appendix 5, wherein the assembled battery is composed of the activated used batteries divided into the same set.

(Appendix 14)
In the method of grading the activated used battery according to the discharge capacity, the discharge capacity is divided into different grade sections with the set capacity difference as an interval, and the discharge capacity is divided into different grade sections according to the grade section in which the discharge capacity exists. The method for repairing a used battery according to Appendix 13, wherein the activated used battery is graded.

(Appendix 15)
The method for repairing a used battery according to Appendix 14, wherein the capacity difference is 0 to 5% of the nominal capacity of the used battery.

(Appendix 16)
The method of grouping the activated used batteries in the same grade based on the charge transfer resistance divides the charge transfer resistance into different grouping sections with a set charge transfer resistance difference as an interval. The method for repairing a used battery according to Appendix 13, wherein the activated used battery is grouped according to a grouping section in which the charge transfer resistance is present.

(Appendix 17)
The method for repairing a used battery according to Appendix 13, wherein the charge transfer resistance difference is 10% to 15% of the average value of the charge transfer resistance of the activated used battery of the same grade.

(Appendix 18)
The method of injecting the electrolytic solution is
The top lid of the repairable used battery is removed, and in an environment where the dew point temperature is −35 ° C. or lower, a part of the protective adhesive of the battery lid plate is cut to form an adhesive coating hole, and the adhesive is formed. The battery lid plate is pierced in accordance with the coated hole, and then vacuuming is started in accordance with the adhesive coated hole using a liquid injection nozzle, and the electrolytic solution is injected after the vacuuming is completed. The method for repairing a used battery according to Appendix 5, wherein the used battery is characterized by the above.

(Appendix 19)
The method for detecting the actual capacity is
The method for repairing a used battery according to Appendix 5, wherein the used battery is charged and discharged for one cycle with a constant current, and the discharge capacity thereof is recorded as the actual capacity.

(Appendix 20)
A method of calculating the weight of the electrolyte injected into each used battery in each repairable used battery pack is
It is characterized by calculating the maximum capacity loss amount of the selected used battery and calculating the mass of the electrolytic solution to be replenished by each used battery in the repairable used battery set. The method for repairing a used battery according to Appendix 5.

Claims (18)

A step of allowing the used battery discharged to the cutoff voltage to stand at room temperature for the first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
A step of charging the used battery to a rated capacity in the range of 20% to 35% of the nominal capacity, measuring the voltage of the used battery at that time, and recording it as a second voltage.
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
Rapid of used batteries comprising the steps of grouping used batteries simultaneously selected within the first preselection set, the second preselection set and the third preselection set. Grouping method. A first threshold value, a second threshold value and a third threshold value are set, the first threshold value is the voltage difference threshold value of the first voltage, and the second threshold value is the voltage difference of the second voltage. The method for rapidly grouping used batteries according to claim 1 , wherein the third threshold value is a voltage difference threshold value of the third voltage. The step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition is
Statistics of the first voltage, the second voltage and the third voltage of each used battery,
Statistics of the first voltage difference, the second voltage difference, and the third voltage difference of each used battery with respect to the first used battery, and
By selecting the used batteries statistically based on the voltage difference threshold of the first voltage to form the first preliminary selection set,
By selecting the used batteries statistically based on the voltage difference threshold of the second voltage to form the second preliminary selection set,
The used battery according to claim 2 , wherein the used battery statistically selected based on the voltage difference threshold of the third voltage is selected to form the third preliminary selection set, and the present invention comprises. How to quickly group batteries. A step of allowing the used battery discharged to the cutoff voltage to stand at room temperature for the first set time, measuring the voltage of the used battery at that time, and recording it as the first voltage.
A step of charging the used battery to a rated capacity in the range of 20% to 35% of the nominal capacity, measuring the voltage of the used battery at that time, and recording it as a second voltage.
A step of allowing the used battery charged to the rated capacity to stand at room temperature for a second set time, measuring the voltage of the used battery at that time, and recording it as a third voltage.
The first determination condition is set based on the first voltage, the second determination condition is set based on the second voltage, and the third determination condition is set based on the third voltage. , A step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition.
A step of completing the above-mentioned determination step for a plurality of used batteries to form a first preliminary selection set, a second preliminary selection set, and a third preliminary selection set.
A step of grouping used batteries simultaneously selected in the first preliminary selection group, the second preliminary selection group, and the third preliminary selection group, and
A step of adjusting the first determination condition, the second determination condition, and the third determination condition to group all used batteries to obtain a plurality of used assembled batteries.
A step of selecting one or more used batteries from each of the used assembled batteries and detecting the actual capacity of the selected used batteries, and
A step of selecting a repairable used battery pack based on the capacity of the selected used battery, and
A step of discharging each used battery in each of the repairable used batteries to its cutoff voltage,
The electrolyte of the weight corresponding to each used battery in each repairable used battery is injected and sealed, but the same weight of the said battery in each used battery in the repairable used battery. The step of injecting the electrolyte and
A method for repairing a used battery, which comprises a step of activating charging / discharging of the used battery into which the electrolytic solution is injected. A first threshold value, a second threshold value and a third threshold value are set, the first threshold value is the voltage difference threshold value of the first voltage, and the second threshold value is the voltage difference of the second voltage. The method for repairing a used battery according to claim 4 , wherein the third threshold value is a voltage difference threshold value of the third voltage. The step of sequentially determining the used battery based on the first determination condition, the second determination condition, and the third determination condition is
Statistics of the first voltage, the second voltage and the third voltage of each used battery,
Statistics of the first voltage difference, the second voltage difference, and the third voltage difference of each used battery with respect to the first used battery, and
By selecting the used batteries statistically based on the voltage difference threshold of the first voltage to form the first preliminary selection set,
By selecting the used batteries statistically based on the voltage difference threshold of the second voltage to form the second preliminary selection set,
The used battery according to claim 5 , wherein the used battery statistically selected based on the voltage difference threshold of the third voltage is selected to form the third preliminary selection set, and the present invention comprises. How to repair the battery. When the actual capacity of the selected used battery is a nominal capacity of 60% to 80%, the used assembled battery in which the selected used battery is present is a repairable used assembled battery. The method for repairing a used battery according to claim 4 , wherein the used battery is characterized. The method of activating charge / discharge is
The used battery into which the electrolytic solution is injected is allowed to stand, the electrolytic solution is sufficiently permeated into the battery, charged to the upper limit of the voltage with the first constant current, and then with the second constant current. The method for repairing a used battery according to claim 4 , wherein the battery is discharged to the cutoff voltage. The first constant current is 0.01C to 0.1C, which is the nominal capacity of the used battery, and the second constant current is 0.5C to 1C, which is the nominal capacity of the used battery. 8. The method for repairing a used battery according to claim 8 . To allow the used battery infused with the electrolytic solution to stand means to allow the repairable used battery infused with the electrolytic solution to stand at 35 ° C to 50 ° C for 1 to 5 days. The method for repairing a used battery according to claim 8 , wherein this is the case. The step further comprises the step of grouping the activated used batteries to form an assembled battery, wherein the step.
To detect the discharge capacity and charge transfer resistance of the activated used battery,
To grade the activated used battery according to the discharge capacity,
Grouping the activated used batteries within the same grade based on the charge transfer resistance, and
The method for repairing a used battery according to claim 4 , wherein the assembled battery is composed of the activated used batteries divided into the same set. In the method of grading the activated used battery according to the discharge capacity, the discharge capacity is divided into different grade sections with the set capacity difference as an interval, and the discharge capacity is divided into different grade sections according to the grade section in which the discharge capacity exists. The method for repairing a used battery according to claim 11 , wherein the activated used battery is graded. The method for repairing a used battery according to claim 12 , wherein the capacity difference is 0 to 5% of the nominal capacity of the used battery. The method of grouping the activated used batteries in the same grade based on the charge transfer resistance divides the charge transfer resistance into different grouping sections with a set charge transfer resistance difference as an interval. The method for repairing a used battery according to claim 11 , wherein the activated used battery is grouped according to a grouping section in which the charge transfer resistance is present. The method for repairing a used battery according to claim 11 , wherein the charge transfer resistance difference is 10% to 15% of an average value of the charge transfer resistance of the activated used battery of the same grade. The method of injecting the electrolytic solution is
The top lid of the repairable used battery is removed, and in an environment where the dew point temperature is −35 ° C. or lower, a part of the protective adhesive of the battery lid plate is cut to form an adhesive coating hole, and the adhesive is formed. The battery lid plate is pierced in accordance with the coated hole, and then vacuuming is started in accordance with the adhesive coated hole using a liquid injection nozzle, and the electrolytic solution is injected after the vacuuming is completed. The method for repairing a used battery according to claim 4 , wherein the used battery is repaired. The method for detecting the actual capacity is
The method for repairing a used battery according to claim 4 , wherein the used battery is charged and discharged for one cycle with a constant current, and the discharge capacity thereof is recorded as the actual capacity. A method of calculating the weight of the electrolyte injected into each used battery in each repairable used battery pack is
It is characterized by calculating the maximum capacity loss amount of the selected used battery and calculating the mass of the electrolytic solution to be replenished by each used battery in the repairable used battery set. The method for repairing a used battery according to claim 4 .

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