CN111580005A - A rapid sorting method and device for cascade utilization of power batteries - Google Patents

Abstract

The invention provides a quick sorting method and device for a echelon utilization power battery, and solves the problems that the sorting time is too long, the cost is too high, and meanwhile, the different performances of the battery cannot be tested at the same time in the conventional echelon utilization battery module. An embodiment of the invention provides a method and a device for rapidly sorting power batteries by gradient utilization, wherein the method comprises the following steps: measuring the open-circuit voltage of each single battery, and screening out a first batch of single batteries capable of being used in a gradient manner according to the open-circuit voltage; screening a second batch of battery monomers capable of being used in a echelon mode from a first batch of battery monomers capable of being used in a echelon mode by using a voltage change value testing method, and sorting according to voltage change values of a plurality of battery monomers; and screening a third batch of battery monomers capable of being used in the echelon by using a different-frequency impedance value testing method from the second batch of battery monomers capable of being used in the echelon, and sorting according to the impedance values of the plurality of battery monomers under different frequencies.

Description

A rapid sorting method and device for cascade utilization of power batteries

technical field

The invention relates to the technical field of batteries, in particular to a rapid sorting method and device for cascade utilization of power batteries.

Background technique

my country has become the world's largest new energy vehicle production and sales country. By the end of 2019, the number of new energy vehicles in my country exceeded 4 million. At present, new energy vehicles mainly use lithium-ion power batteries as the power source. By the end of 2019, power batteries The cumulative loading volume exceeds 200GWh. The performance of the power battery continues to decline during the on-board use phase, and the performance difference between the batteries is getting bigger and bigger. When the battery performance cannot meet the application requirements of new energy vehicles, it is necessary to retire from the car. Among the retired power batteries, a large part also has high residual energy. These batteries may be used in occasions with lower performance requirements to realize the cascade utilization of power batteries.

New batteries will be sorted according to battery capacity, internal resistance, open circuit voltage, self-discharge and other parameters before use to ensure a good consistency between batteries. Compared with new batteries, after long-term use of retired power batteries, the performance difference between batteries increases significantly, and the consistency is obviously deteriorated. Therefore, they need to be re-sorted before cascade utilization to ensure that battery packs are used in cascades. There is better consistency and performance in the process. Since the state of power batteries is usually unknown when they are retired, traditionally, the method of sorting new batteries is mainly used to test their capacity, internal resistance, open circuit voltage, self-discharge and other parameters one by one, and then set certain parameters for different parameters. Deviation range, so the batteries that meet the requirements are sorted out. Although the traditional method can accurately measure the battery capacity, internal resistance, self-discharge and other parameters, the test time is long, the capacity test takes several hours to ten hours, and the self-discharge test takes several days to ten days. It needs to occupy a lot of charge and discharge test equipment, which results in a significant increase in the cost of sorting the power battery for cascade utilization; and for the power battery for cascade utilization, its residual value is significantly lower than that of the new battery, and the higher sorting cost will be greatly Reduce the economy of the cascade utilization stage; and if only test the voltage and internal resistance (usually only test 1000Hz frequency), do not test the capacity and self-discharge performance that takes a long time, and can not more accurately reflect the state of the power battery in the cascade utilization , resulting in an unsatisfactory sorting effect. Therefore, for the cascade utilization of power batteries, it is necessary to develop a fast sorting method, which can greatly shorten the battery sorting time, and at the same time take into account the test and analysis of different battery performances, so as to reduce the cascade utilization of power battery sorting costs. Improve the economy of power battery cascade utilization.

SUMMARY OF THE INVENTION

In view of this, the embodiment of the present invention provides a rapid sorting method and device for cascade utilization of power batteries, which solves the problem that the sorting time of the current cascade utilization battery module is too long, the cost is too high, and the test of different performances of batteries cannot be taken into account at the same time. question.

An embodiment of the present invention provides a rapid sorting method of power batteries for cascade utilization, including: measuring the open circuit voltage of each of the battery cells, and screening out the first batch of battery cells that can be used for cascade utilization according to the open circuit voltage. In the first batch of battery cells that can be used for cascade utilization, use the voltage change value test method to screen out the second batch of battery cells that can be used for cascade utilization, and classify them according to the voltage change values of a plurality of the battery cells. select; and screen out the third batch of battery cells that can be used for cascade utilization in the second batch of battery cells that can be used for cascade utilization by using the impedance value test method at different frequencies. The impedance value is sorted.

In an embodiment, the measuring the open circuit voltage of each of the battery cells, and screening out the first batch of battery cells that can be used for cascade utilization according to the open circuit voltage includes: comparing the open circuit voltage value with the first batch of battery cells. The preset ranges are compared, and the first batch of battery cells that can be used in cascade and the first batch of battery cells that cannot be used in cascade are screened out, and the first batch of batteries that can be used in cascade is selected according to the open circuit voltage value. Monomers are sorted.

In one embodiment, the first preset range is greater than or equal to 2.5V or less than or equal to 3.5V.

In one embodiment, the second batch of battery cells that can be used for cascade utilization is selected from the first batch of battery cells that can be used for cascade utilization by using a voltage change value test method, and a plurality of battery cells that can be used for cascade use are screened out according to a plurality of battery cells. Sorting the voltage change value of the battery cell, including: recording the first voltage at the start of charging or discharging of the battery cell; charging or discharging the battery cell for a preset time according to the open-circuit voltage, recording the battery cell The second voltage at the end of charging or discharging of the battery cells, calculate the battery voltage change value within a preset time; calculate the average value of the voltage change values of all the battery cells; calculate the voltage change value of the battery cells A first ratio is performed with the average value, and whether the battery module can be used in a step-by-step manner is judged according to the first ratio value;

In one embodiment, calculating a first ratio between the voltage change value of the battery cell and the average value, and judging whether the battery module can be used in a step-by-step manner according to the first ratio, comprising: : The battery cells with the first ratio greater than 1.5 are not used in cascade.

In an embodiment, before the recording of the first voltage at the start of charging or discharging of the battery cell, the method further includes: comparing the open-circuit voltage with a second preset range, and determining whether the battery is suitable for use in the battery. The cell is charged or discharged.

In one embodiment, the comparing the open-circuit voltage with a second preset range to determine whether to charge or discharge the battery cell includes: for the battery cell with the open-circuit voltage greater than 3.25V and/or charging the battery cells with the open circuit voltage less than 3.25V.

In one embodiment, the third batch of battery cells capable of step utilization is screened out by using the impedance value test method at different frequencies from the second batch of battery cells capable of step utilization. Sorting the impedance values of the battery cells at different frequencies, including: selecting a frequency point in a plurality of different frequency bands, respectively measuring the impedance values of the battery cells at the plurality of frequency points; The average value of the impedance values of the battery cells at each of the frequency points; the second ratio of each of the impedance values to the average value is calculated respectively, and according to the second ratio, it is judged whether the battery module is performing the steps utilizing; and sorting according to impedance values of a plurality of the battery cells at a plurality of the frequencies.

In one embodiment, calculating a second ratio of each of the impedance values to the average value, and judging whether the battery module is used in a cascade manner according to the second ratio includes: the battery module is in multiple The battery cells with at least one of the second ratios at the frequency points greater than 1.8 are not used for cascade utilization.

A rapid sorting device for cascade utilization of power batteries, comprising: a detection unit configured to measure the open circuit voltage of each battery cell, the first voltage of the battery cell at the start of charging or discharging, the battery cell the second voltage of the battery at the end of charging or discharging and the impedance value of the battery cell at a frequency point selected in a plurality of different frequency segments; and a calculation unit configured to compare the open-circuit voltage value with the first preset range. Comparing and screening out the first batch of battery cells that can be used for cascade utilization and sorting according to the open circuit voltage, and using the voltage change value test method to screen out the second batch of battery cells that can be used for cascade utilization in the first batch. The battery cells of the cascade utilization and the sorting according to the voltage change value, and the third batch of battery cells that can be used for the cascade utilization are screened out by using the impedance value test method of different frequencies in the second batch of battery cells that can be used for the cascade utilization. and sorting according to the frequency impedance value.

The embodiment of the present invention provides a rapid sorting method and device for cascade utilization of power batteries, by measuring the open circuit voltage of each battery cell, and screening out the first batch of battery cells that can be used for cascade utilization according to the open circuit voltage;

In the first batch of battery cells that can be used for cascade utilization, the second batch of battery cells that can be used for cascade utilization is screened out by the voltage change value test method, and sorted according to the voltage change value of multiple battery cells; From the second batch of battery cells that can be used for cascade utilization, the third batch of battery cells that can be used for cascade utilization is screened out by using the impedance value test method at different frequencies, and the sorting is carried out according to the impedance values of multiple battery cells at different frequencies. Through the three-level screening, multiple performance indicators such as capacity, voltage, internal resistance, and self-discharge of the power battery for cascade utilization are taken into account, so as to improve the technical economy of the cascade utilization of power batteries. And compared with the traditional charging and discharging test method, the present application uses the open circuit voltage of the power battery, the voltage change value, the impedance value at high frequency, medium frequency and low frequency to sort them according to the ladder, which can be completed within 5 minutes. The sorting work of batteries realizes the rapid sorting of power batteries for cascade utilization, and greatly shortens the sorting time of power batteries for cascade utilization.

Description of drawings

The accompanying drawings forming a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

FIG. 1 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by an embodiment of the present invention.

FIG. 2 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by another embodiment of the present invention.

FIG. 3 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by another embodiment of the present invention.

FIG. 4 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by another embodiment of the present invention.

FIG. 5 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by another embodiment of the present invention.

FIG. 6 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by another embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a rapid sorting device for cascade utilization of power batteries according to an embodiment of the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict.

The following detailed descriptions are all exemplary descriptions and are intended to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

FIG. 1 is a schematic flowchart of a rapid sorting method for cascade utilization of power batteries provided by an embodiment of the present invention.

As shown in Figure 1, the battery module includes a plurality of battery cells, and the rapid sorting method of the cascade utilization power battery includes:

Step 01: Measure the open-circuit voltage of each battery cell, and screen out the first batch of battery cells that can be used in cascade according to the open-circuit voltage; open-circuit voltage refers to the terminal voltage of the battery in the open-circuit state, and the open-circuit voltage of the battery is equal to the battery The difference between the positive electrode potential and the negative electrode potential of the battery when the battery is open (ie, when no current flows through the two poles), the open circuit voltage is expressed in V. Echelon utilization refers to the continuous use process in which a product that has been used has reached its original design life, and then restores all or part of its functions through other methods, and this process belongs to the basic same-level or downgraded application method. "Ladder utilization" and "gradient utilization, stepped utilization, and degraded use" are basically the same in concept, but they cannot be regarded as refurbished use.

Step 02: Use the voltage change value test method to screen out the second batch of battery cells that can be used for cascade utilization in the first batch of battery cells that can be used for cascade utilization, and sort them according to the voltage change values of multiple battery cells ;as well as

Step 03: In the second batch of battery cells that can be used for cascade utilization, the third batch of battery cells that can be used for cascade utilization is screened out by using the impedance value test method at different frequencies. According to the impedance values of multiple battery cells at different frequencies Sort.

Through the three-level screening, multiple performance indicators such as capacity, voltage, internal resistance, and self-discharge of the power battery for cascade utilization are taken into account, so as to improve the technical economy of the cascade utilization of power batteries. And compared with the traditional charging and discharging test method, the present application uses the open circuit voltage of the power battery, the voltage change value, the impedance value at high frequency, medium frequency and low frequency to sort them according to the ladder, which can be completed within 5 minutes. The sorting work of batteries realizes the rapid sorting of power batteries for cascade utilization, and greatly shortens the sorting time of power batteries for cascade utilization.

It can be understood that a plurality of battery cells can be connected in series or in parallel to form a battery module in any order, and the invention does not limit the arrangement order of the plurality of battery cells without affecting the sorting method of the battery module by gradient utilization.

FIG. 2 is a schematic flowchart of a method for sorting battery modules by gradient utilization according to another embodiment of the present invention.

As shown in FIG. 2 , measuring the open circuit voltage of each battery cell, and selecting the first batch of battery cells that can be used for cascade utilization according to the open circuit voltage includes: Step 011 : comparing the open circuit voltage value with the first preset range, The first batch of battery cells that can be used in cascade and the first batch of battery cells that cannot be used in cascade are screened out, and the first batch of battery cells that can be used in cascade are sorted according to the open circuit voltage value. For battery cells with an open circuit voltage greater than 3.5V or less than 2.5V, there is a possibility of overcharge or overdischarge during historical use, and there is a great safety hazard, so cascade utilization is not performed; for battery cells with an open circuit voltage of 2.5V to 3.15V When sorting, the battery cells with the difference (range) between the maximum and minimum open-circuit voltages of the echelon use power batteries of less than or equal to 100mV are divided into the same group; for power batteries with an open-circuit voltage of 3.15V to 3.35V, the separation When selecting, the battery cells with a voltage range of less than or equal to 30mV are divided into the same group; for power batteries with an open circuit voltage of 3.35V to 3.5V, the battery cells with a range of less than or equal to 50mV are divided into the same group during sorting.

It can be understood that the first preset range is greater than or equal to 2.5V or less than or equal to 3.5V, the first preset range value is not only limited between 2.5V and 3.5V, the first preset range value can be selected, The present invention does not limit the specific numerical interval of the first preset range value.

It can also be understood that the specific numerical range for sorting the battery cells according to the open circuit voltage is not limited to the preference in this embodiment, and the specific numerical range for sorting the battery cells according to the open circuit voltage can be selected. Yes, the specific numerical range for sorting the battery cells according to the open circuit voltage is not limited.

FIG. 3 is a schematic flowchart of a method for sorting battery modules by gradient utilization according to another embodiment of the present invention.

As shown in Figure 3, in the first batch of battery cells that can be used for cascade utilization, the voltage change value test method is used to screen out the second batch of battery cells that can be used for cascade utilization, and according to the voltage change value of multiple battery cells Sorting, including:

Step 021: record the first voltage at the start of charging or discharging of the first batch of battery cells capable of cascade utilization;

Step 022: Charge or discharge the first batch of battery cells capable of cascade utilization for a preset time according to the open-circuit voltage, record the second voltage at the end of charging or discharge of the first batch of battery cells capable of cascade utilization, and calculate the preset time. The battery voltage change value within the set time;

Step 023: Calculate the average value of the voltage change values of all the first batch of battery cells that can be used in cascade;

Step 024: Calculate the voltage change value and the average value of the first batch of battery cells that can be used for cascade utilization to perform a first ratio, determine whether the battery module can be used for cascade use according to the first ratio, and screen out the second batch of batteries that can be used for cascade use. of battery cells;

Step 025 : Sorting according to the voltage change value of the second batch of battery cells capable of step-by-step utilization.

According to the open circuit voltage of the battery cell, charge or discharge the battery cell at a rate of 0.5C of the rated capacity for 3 minutes, record the voltage at the beginning of the charging or discharging of the battery cell as V1, and the voltage at the end time as V2, calculate for 3 minutes The voltage change value ΔV of the inner battery cell: ΔV=V1-V2 Then take the absolute value of the change value to obtain |ΔV|. Calculate the average value of the absolute value of the voltage change of all battery cells participating in the test |ΔV|ave, |ΔV|ave=(|ΔV1|+|ΔV2|+…|ΔVr|....+|ΔVn|)/n , |ΔVr| is the absolute value of the voltage change of the rth battery cell in 3 minutes, and n is the number of batteries. Calculate the ratio of the absolute value of the voltage change of each battery cell to the average value |ΔV|ave in 3 minutes. For a battery cell whose ratio is greater than 1.5, it indicates that the voltage changes rapidly during the charging or discharging process and the battery capacity is low. , do not use cascade. Sorting is carried out according to the absolute value of the voltage change |ΔV| of the battery cells during charging and discharging in 3 minutes, and the difference between the maximum value and the minimum value of the absolute value of the voltage cell change |ΔV| in the same group is less than or equal to |ΔV|ave 10% of the battery cells are divided into the same group, that is, the battery cells of |ΔV|max-|ΔV|min≤10%*|ΔV|ave are divided into the same group.

FIG. 4 is a schematic flowchart of a method for sorting battery modules by gradient utilization according to another embodiment of the present invention.

As shown in FIG. 4 , before recording the first voltage at the start of charging or discharging of the first batch of battery cells capable of echelon utilization, the method further includes:

Step 020: Compare the open-circuit voltage with the second preset range, and determine whether to charge or discharge the first batch of battery cells that can be used in a cascade. According to the open circuit voltage of the first batch of battery cells that can be used for cascade utilization, it is judged whether to charge or discharge the first batch of battery cells that can be used for cascade utilization. The first batch of battery cells with an open circuit voltage less than 3.25V that can be used in a cascade is charged.

FIG. 5 is a schematic flowchart of a method for sorting battery modules by gradient utilization according to another embodiment of the present invention.

As shown in Figure 5, in the second batch of battery cells that can be used for cascade utilization, the third batch of battery cells that can be used for cascade utilization is screened out by using the impedance value test method at different frequencies. The impedance value is sorted, including:

Step 031: Select a frequency point in a plurality of different frequency segments, respectively measure the impedance values of the second batch of battery cells that can be used in cascade at multiple frequency points;

Step 032: Calculate the average value of impedance values at each frequency point of a plurality of second batches of battery cells capable of cascade utilization;

Step 033: Calculate the second ratio of each impedance value to the average value respectively, determine whether the battery module is used for cascade utilization according to the second ratio, and screen out the third batch of battery cells that can be used for cascade use;

Step 034: Sort according to the impedance values of the plurality of third batches of battery cells that can be used in cascade at multiple frequencies.

FIG. 6 is a schematic flowchart of a method for sorting battery modules by gradient utilization according to another embodiment of the present invention.

As shown in Figure 6, the second ratio of each impedance value to the average value is calculated respectively, and according to the second ratio, it is judged whether the battery module is used in a cascade, including:

Step 0331 : At least one battery cell whose second ratio is greater than 1.8 among the second ratios of the battery module at multiple frequency points is not used for cascade utilization.

Select a frequency point in the high frequency range (500-2000Hz), medium frequency range (5-100Hz) and low frequency range (0.02-0.5Hz) respectively, and test the impedance value of the battery cell at these three frequency points. The impedance value of the high frequency point is recorded as Rh, the impedance value of the middle frequency point is recorded as Rm, and the impedance value of the low frequency point is recorded as Rl.

①Calculate the average value of impedance values of all batteries participating in the sorting at 3 frequency points, the method is as follows:

Rh-ave=(Rh-1+Rh-2+...+Rh-r+...+Rh-n)

Rm-ave=(Rm-1+Rm-2+...+Rm-r+...+Rm-n)

R1-ave=(R1-1+R1-2+...+R1-r+...+R1-n)

Among them, Rh-r is the impedance value of the rth battery cell at the high frequency point, Rm-r is the impedance value of the rth battery cell at the middle frequency point, and Rl-r is the rth battery cell at the low frequency point. The impedance value of , n is the number of battery cells involved in sorting.

② Calculate the ratio of the impedance value of each battery cell at 3 frequency points to the average impedance value at this frequency point, namely Rh-r/Rh-ave, Rm-r/Rm-ave and Rl-r/Rl-ave , for the three ratios, there is always a battery cell greater than 1.8, indicating that its impedance value is large, and it is not used in cascade.

③ Sort according to the impedance values of the battery cells at 3 frequencies. For the impedance value Rh at the high frequency point, the difference between the maximum value and the minimum value of the impedance of the battery cells in the same group is less than or equal to 20% of the average value at this frequency point, that is:

Rh-max-Rh-min≤20%*Rh-ave

For the impedance value Rm at the middle frequency point, the difference between the maximum value and the minimum value of the impedance of the battery cells in the same group is less than or equal to 15% of the average value at this frequency point, that is:

Rm-max-Rm-min≤15%*Rm-ave

For the impedance value Rl at the low frequency point, the difference between the maximum value and the minimum value of the impedance of the battery cells in the same group is less than or equal to 15% of the average value at this frequency point, that is:

Rl-max-Rl-min≤15%*Rl-ave

In this application, the open-circuit voltage, the battery voltage change during charging or discharging, and the impedance value at different frequency points are tested for the battery module with the value of cascade utilization. On this basis, a certain deviation range is set for the test results of different parameters. Realize the rapid sorting of cascade utilization power batteries, which can complete the rapid sorting of cascade utilization battery modules within 5 minutes, which greatly reduces the sorting cost of cascade utilization battery modules, and also takes into account the cascade utilization battery modules. Main performance parameters. The traditional battery capacity test usually adopts the method of charging and discharging, which takes a long time (several hours). During the charging and discharging process, the battery voltage continues to change. Under the condition of fixed charge and discharge current and time, the capacity of the battery can be characterized to a certain extent by the change value of the battery voltage. The impedance of the battery cell is mainly composed of the ohmic impedance in the high frequency region, the charge transfer impedance in the intermediate frequency region and the diffusion impedance in the low frequency region. The internal resistance characteristics of the battery during charging and discharging, and the diffusion impedance in the low-frequency region has a certain relationship with the self-discharge rate of the battery. Therefore, the internal resistance and self-discharge of the power battery can be reflected by testing the impedance values in different frequency bands. discharge performance.

Through the three-level screening, multiple performance indicators such as capacity, voltage, internal resistance, and self-discharge of the power battery for cascade utilization are taken into account, so as to improve the technical economy of the cascade utilization of power batteries. And compared with the traditional charging and discharging test method, the present application uses the open circuit voltage of the power battery, the voltage change value, the impedance value at high frequency, medium frequency and low frequency to sort them according to the ladder, which can be completed within 5 minutes. The sorting work of batteries realizes the rapid sorting of power batteries for cascade utilization, and greatly shortens the sorting time of power batteries for cascade utilization.

FIG. 7 is a schematic structural diagram of a battery module device for gradient utilization according to an embodiment of the present invention.

As shown in FIG. 7 , the sorting device for battery modules for cascade utilization includes: a detection unit configured to measure the open-circuit voltage of each battery cell, the first voltage of the battery cell at the start of charging or discharging, the battery cell The second voltage at the end of charging or discharging and the impedance value of the battery cell at one frequency point in a plurality of different frequency bands respectively; the calculation unit is configured to compare the open-circuit voltage value with the first preset range to filter out the first A batch of battery cells that can be used for cascade utilization and sorted according to the open circuit voltage, and the second batch of battery cells that can be used for cascade utilization is screened out by the voltage change value test method in the first batch of battery cells that can be used for cascade use And sorting according to the voltage change value, and screening out the third batch of battery cells that can be used for cascade utilization in the second batch of battery cells that can be used for cascade utilization using different frequency impedance value testing methods, and sorting according to the frequency impedance value. . The battery module sorting device for cascade utilization uses the method for sorting battery modules for cascade utilization described in the above embodiment to sort the battery modules.

It can be understood that the cascade utilization battery module sorting device can sort chemical energy storage batteries and power batteries, etc. The types of batteries sorted by the cascade utilization battery module sorting device are various. There is no limitation on what type of batteries the group sorting device sorts.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims (10)

1. A quick sorting method for gradient utilization of power batteries is characterized in that a battery module comprises a plurality of battery monomers, and the sorting method comprises the following steps:

measuring the open-circuit voltage of each single battery, and screening out a first batch of single batteries capable of being used in a gradient manner according to the open-circuit voltage;

screening a second batch of battery monomers capable of being used in a echelon mode from a first batch of battery monomers capable of being used in a echelon mode by using a voltage change value testing method, and sorting according to voltage change values of a plurality of battery monomers; and

screening a third batch of battery cells capable of being used in a echelon mode from the second batch of battery cells capable of being used in the echelon mode by using a different-frequency impedance value testing method, and sorting according to impedance values of the plurality of battery cells under different frequencies.

2. The method for rapidly sorting the gradient-utilization power batteries according to claim 1, wherein the step of sorting out the first battery cells capable of being used in the gradient according to the open-circuit voltage comprises the following steps: and comparing the open-circuit voltage value with a first preset range, screening out the first battery monomer capable of realizing the echelon utilization and the first battery monomer incapable of realizing the echelon utilization, and sorting the first battery monomer capable of realizing the echelon utilization according to the open-circuit voltage value.

3. The method for rapidly sorting power batteries by gradient utilization according to claim 2, wherein the first preset range is greater than or equal to 2.5V or less than or equal to 3.5V.

4. The method for rapidly sorting the gradient-utilization power batteries according to claim 2, wherein the step-utilization power battery sorting method is used for sorting a second batch of gradient-utilization battery cells from a first batch of gradient-utilization battery cells and sorting the battery cells according to voltage variation values of a plurality of battery cells, and comprises the following steps:

recording a first voltage of the first batch of battery single cells capable of being used in a gradient manner at the initial charging or discharging moment;

charging or discharging the first batch of battery monomers capable of being used in the echelon for preset time according to the open-circuit voltage, recording a second voltage at the moment when the charging or discharging of the first batch of battery monomers capable of being used in the echelon is finished, and calculating a battery voltage change value in the preset time;

calculating the average value of the voltage change values of all the first battery cells capable of being used in a gradient manner;

calculating a first ratio of the voltage change value of the first batch of battery monomers capable of being used in the echelon process to the average value, judging whether the battery module can be used in the echelon process according to the first ratio, and screening a second batch of battery monomers capable of being used in the echelon process; and

and sorting according to the voltage change values of the battery monomers which can be used in the second batch in a gradient manner.

5. The method for rapidly sorting the power batteries for the echelon utilization according to claim 4, wherein the step of calculating a first ratio of the voltage variation value of the first battery cells capable of being used for the echelon utilization to the average value and judging whether the battery module is capable of being used for the echelon utilization according to the first ratio comprises: the first battery cells with the first ratio larger than 1.5 capable of being used in the echelon mode are not used in the echelon mode.

6. The method for rapidly sorting gradient-utilization power batteries according to claim 4, wherein before the recording the first voltage at the initial charging or discharging time of the first battery cells capable of being used for gradient utilization, the method further comprises:

and comparing the open-circuit voltage with a second preset range, and judging whether the first batch of battery monomers capable of being used in a gradient manner are charged or discharged.

7. The method for rapidly sorting power batteries by echelon utilization according to claim 6, wherein the step of comparing the open-circuit voltage with a second preset range to judge whether to charge or discharge the battery cell comprises:

discharging the first battery cells with the open-circuit voltage larger than 3.25V and capable of being used in a graded mode; and/or

Charging the first battery cells capable of being used in a echelon mode, wherein the open-circuit voltage of the first battery cells is less than 3.25V.

8. The rapid sorting method for gradient utilization power batteries according to claim 4, wherein a third batch of battery cells capable of being used in a gradient manner is screened out from a second batch of battery cells capable of being used in a gradient manner by using a different-frequency impedance value testing method, and sorting is performed according to impedance values of a plurality of battery cells at different frequencies, and the method comprises the following steps:

respectively selecting a frequency point in a plurality of different frequency sections, and respectively measuring the impedance values of the second batch of battery cells capable of being used in a gradient manner at the plurality of frequency points;

respectively calculating the average value of the impedance values of a plurality of second battery cells which can be used in a gradient manner at each frequency point;

respectively calculating second ratios of the impedance values and the average value, judging whether the battery module is subjected to echelon utilization according to the second ratios, and screening out a third batch of battery monomers capable of being subjected to echelon utilization; and

sorting according to the impedance values of the third battery cells capable of being used in a gradient mode at the frequencies.

9. The method for rapidly sorting the power batteries used in the echelon according to claim 8, wherein a second ratio of each impedance value to the average value is calculated, and whether the battery module is used in the echelon is determined according to the second ratio comprises:

at least one of the second ratios of the battery module at a plurality of frequency points is greater than 1.8, and the battery monomer is not utilized in a gradient manner.

10. The utility model provides a echelon utilization power battery's quick sorting unit which characterized in that includes:

the detection unit is configured to measure an open-circuit voltage of each battery cell, a first voltage of the battery cell at a charging or discharging starting moment, a second voltage of the battery cell at a charging or discharging ending moment, and impedance values of the battery cell at a frequency point selected from a plurality of different frequency bands; and

the calculation unit is configured to compare the open-circuit voltage value with a first preset range to screen out a first batch of battery cells capable of being used in a gradient mode, screen out the first batch of battery cells capable of being used in the gradient mode according to the open-circuit voltage, screen out a second batch of battery cells capable of being used in the gradient mode in the first batch of battery cells capable of being used in the gradient mode by using a voltage change value testing method, screen out a third batch of battery cells capable of being used in the gradient mode in the second batch of battery cells capable of being used in the gradient mode by using a different-frequency impedance value testing method, and screen out the third batch of battery cells capable of being used in the gradient mode according to the frequency impedance value.

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