Battery screening method, battery screening system and computer program product

Abstract

The invention discloses a battery screening method. The method comprises the following steps: acquiring an associated data set between charge-discharge capacity and voltage value of each retired battery; determining the average internal resistance of each retired battery according to the associated data set; and screening the batteries according to the average internal resistance of each retired battery. According to the method, the internal resistance consistency of the decommissioned batteries is screened based on the average internal resistance, the decommissioned batteries can be screened without complex equipment on the premise that the decommissioned batteries are not damaged, and the decommissioned batteries with high consistency are rapidly screened out for battery recombination while the economic cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery screening method, a battery screening system and a computer program product. Background Art

[0002] When the battery capacity of electric vehicles declines to below 80%, the power battery will face retirement, but it still has great utilization value at this time, and direct elimination will waste a lot of resources. The cost of lithium batteries can be effectively reduced by cascading the use of retired batteries. Excessive inconsistency in internal resistance between retired batteries will bring difficulties to battery reorganization, and lead to safety hazards and capacity attenuation in the reorganized battery pack.

[0003] In the related art, the internal resistance of each retired battery is obtained through internal resistance testing, so as to screen the retired batteries through internal resistance. The internal resistance test includes AC internal resistance test and DC internal resistance test. The AC internal resistance test is relatively complicated and is limited by the detection equipment, which is difficult to apply to lithium battery packs. The DC internal resistance test requires external processing experiments, which may damage the battery during the test and even cause safety accidents. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a battery screening method, which screens the internal resistance consistency of retired batteries based on the average internal resistance, can screen retired batteries without damaging the retired batteries and without using complex equipment, and can quickly screen out retired batteries with high consistency for battery reorganization while reducing economic costs.

[0005] A second objective of the present invention is to provide a battery screening system.

[0006] A third object of the present invention is to provide a computer program product.

[0007] A fourth objective of the present invention is to provide a battery screening system.

[0008] In order to solve the above problems, a first embodiment of the present invention proposes a battery screening method, comprising: obtaining a correlation data set between the charge and discharge capacity and the voltage value of each retired battery; determining the average internal resistance of each retired battery according to the correlation data set; and performing battery screening according to the average internal resistance of each retired battery.

[0009] According to the battery screening method of the embodiment of the present invention, the average internal resistance is introduced to perform consistency screening of retired batteries, that is, the average internal resistance of each retired battery is determined by the correlation data set between the charge and discharge capacity and the voltage value of each retired battery, so that the retired batteries are screened by utilizing the distribution characteristics of the average internal resistance. Therefore, the retired batteries can be screened without using complex equipment without damaging the retired batteries, thereby reducing the economic cost while quickly screening out retired batteries with high consistency for battery reorganization.

[0010] In some embodiments, obtaining a correlation data set between the charge and discharge capacity and the voltage value of each retired battery includes: charging and discharging each retired battery under a preset charge and discharge current; obtaining a first correlation data set between the charge capacity and the voltage value of each retired battery within a target voltage range; obtaining a second correlation data set between the discharge capacity and the voltage value of each retired battery within the target voltage range. In some embodiments, determining the average internal resistance of each retired battery according to the associated data set includes: determining the average charging voltage of each retired battery in the target voltage segment according to the first associated data set; determining the average discharging voltage of each retired battery in the target voltage segment according to the second associated data set; calculating the voltage difference between the average charging voltage and the average discharging voltage; and determining the average internal resistance according to the voltage difference and the preset charge and discharge current.

[0011] In some embodiments, battery screening is performed based on the average internal resistance of each retired battery, including: determining a health status value of each retired battery; grouping all retired batteries according to the health status value to obtain multiple battery pre-matching groups; determining an internal resistance screening threshold corresponding to each battery pre-matching group according to the average internal resistance of each retired battery in each battery pre-matching group; and determining a screening result for each battery pre-matching group according to the internal resistance screening threshold.

[0012] In some embodiments, the health status value is a capacity value or a SOH value of the retired battery.

[0013] In some embodiments, all retired batteries are grouped according to the health status value, including: determining multiple preset health status value ranges required for grouping; based on the health status value of each retired battery, the retired batteries in the same preset health status value range are grouped as a battery pre-assignment group.

[0014] In some embodiments, the internal resistance screening threshold corresponding to each battery pre-matching group is determined according to the average internal resistance of each retired battery in each battery pre-matching group, including: determining the median internal resistance value corresponding to each battery pre-matching group according to the average internal resistance of each retired battery in each battery pre-matching group; determining the upper quartile internal resistance value and the lower quartile internal resistance value corresponding to each battery pre-matching group based on the interquartile range method according to the median internal resistance value corresponding to each battery pre-matching group; and using the median internal resistance value, the upper quartile internal resistance value and the lower quartile internal resistance value as the internal resistance screening value.

[0015] In some embodiments, the screening results of each battery pre-matching group are determined according to the internal resistance screening threshold, including: for each battery pre-matching group, the batteries that meet the condition that the average internal resistance value is less than or equal to the lower quartile internal resistance value are regarded as first-category batteries; the batteries that meet the condition that the average internal resistance value is greater than the lower quartile internal resistance value and the average internal resistance value is less than or equal to the median internal resistance value are regarded as second-category batteries; the batteries that meet the condition that the average internal resistance value is greater than the median internal resistance value and the average internal resistance value is less than or equal to the upper quartile internal resistance value are regarded as third-category batteries.

[0016] In some embodiments, the internal resistance screening value also includes a maximum internal resistance value, and the method further includes: determining a preset screening allowable internal resistance value; and calculating the sum of the upper quartile internal resistance value and the preset screening allowable internal resistance value to obtain the maximum internal resistance value.

[0017] In some embodiments, determining the screening result of each battery pre-matching group according to the internal resistance screening threshold also includes: treating batteries that meet the conditions that the average internal resistance value is greater than the upper quartile internal resistance value and the average internal resistance value is less than or equal to the maximum internal resistance value as fourth category batteries.

[0018] In some embodiments, determining the screening result of each battery pre-matching group according to the internal resistance screening threshold value further includes: scrapping and recycling batteries that meet the condition that the average internal resistance value is greater than the maximum internal resistance value.

[0019] A second aspect of the present invention provides a battery screening system, comprising: a data acquisition module for acquiring a data set of associations between the charge and discharge capacity and the voltage value of each retired battery; an internal resistance determination module for determining the average internal resistance of each retired battery based on the associated data set; and a screening module for performing battery screening based on the average internal resistance of each retired battery.

[0020] According to the battery screening system of the embodiment of the present invention, a data set of associations between the charge and discharge capacity and the voltage value of each retired battery acquired by the data acquisition module is sent to the internal resistance determination module. The internal resistance determination module determines the average internal resistance of each retired battery through the data set of associations between the charge and discharge capacity and the voltage value of each retired battery, and sends the average internal resistance to the screening module, so that the screening module can screen the retired batteries according to the distribution characteristics of the average internal resistance. Therefore, the battery screening system can screen the retired batteries without using complex equipment without damaging the retired batteries, thereby reducing economic costs and being able to quickly screen out retired batteries with high consistency for battery reorganization.

[0021] A third aspect of the present invention provides a computer program product, including a computer program, which implements the steps of the battery screening method described in the above embodiment when executed by a processor.

[0022] The fourth aspect of the present invention proposes a battery screening system, comprising: at least one processor; a memory communicatively connected to at least one of the processors; wherein the memory stores a computer program executable by at least one of the processors, and when at least one of the processors executes the computer program, the battery screening method described in the above embodiment is implemented.

[0023] According to the battery screening system of the embodiment of the present invention, the battery screening method of the above embodiment is implemented by executing a computer program through a processor. Under the premise of not damaging the retired batteries, retired batteries can be screened without using complex equipment, thereby reducing economic costs and quickly screening out retired batteries with high consistency for battery reorganization.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a flow chart of a battery screening method according to one embodiment of the present invention; Figure 2 is a schematic diagram of a first correlation data set between charging capacity and voltage value according to an embodiment of the present invention; Figure 3 is a flow chart of a battery screening method according to another embodiment of the present invention; Figure 4 is a schematic diagram of the variation trend of the average voltage and the average internal resistance of retired batteries according to one embodiment of the present invention; Figure 5 is a box diagram of average internal resistance in different capacity ranges according to an embodiment of the present invention; Figure 6 is a structural block diagram of a battery screening system according to an embodiment of the present invention; Figure 7 is a structural block diagram of a battery screening system according to another embodiment of the present invention.

[0026] Reference numerals: Battery screening system 100; Data acquisition module 10; internal resistance determination module 20; screening module 30; processor 40; memory 50. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, and the embodiments described with reference to the accompanying drawings are exemplary.

[0028] In electric vehicles, when the capacity of power batteries declines to below 80%, they will face retirement. Direct elimination at this time will waste a lot of resources. In order to utilize retired batteries, retired batteries are usually put into some energy storage conditions with small charge and discharge rates to achieve cascade utilization. This method can effectively reduce the cost of lithium batteries. However, due to differences in the use conditions of power batteries, such as temperature, long-term storage, cycle aging, high-rate current and other multiple factors, the internal resistance inconsistency of each single cell in the reorganized battery pack will increase, which makes the consistency of the cascade utilization battery far less than that of new batteries. In the battery packs connected in series and parallel, the distribution of single cell resistance is closely related to the consistency of the battery pack. The inconsistency of the internal resistance of single cells in the battery pack will cause some single cells to be overcharged and over-discharged for a long time, which is easy to induce lithium precipitation, increase the safety hazards such as internal short circuit and thermal runaway, and also affect the correct estimation of the battery pack state of charge SOC, health state SOH and other values, and accelerate the capacity decay and life decay of the battery pack.

[0029] Therefore, retired batteries need to be screened in order to effectively utilize them. In the prior art, the screening of retired batteries has the problems of high economic cost, difficulty in application, time-consuming and labor-intensive, and may also cause damage to the retired batteries.

[0030] In order to solve the above problems, an embodiment of the first aspect of the present invention proposes a battery screening method, which screens the internal resistance consistency of retired batteries based on the average internal resistance. Retired batteries can be screened without using complex equipment, thereby reducing economic costs and quickly screening out retired batteries with high consistency for battery reorganization.

[0031] Reference below Figure 1 The battery screening method according to an embodiment of the present invention is described. The method at least includes steps S1 to S3. The specific steps are as follows: Step S1, obtaining a correlation data set between the charge and discharge capacity and the voltage value of each retired battery.

[0032] Specifically, a power battery charge and discharge test system is used to perform charge and discharge tests on each retired battery, and its charge capacity, discharge capacity and voltage during the charge and discharge process are recorded. The obtained data are sorted to obtain a correlation data set between its charge and discharge capacity and voltage value, for example, sorted into a capacity-voltage curve. Compared with the prior art, no other equipment is required for electrochemical testing. Among them, in actual tests, retired batteries may have different correlation data sets between their charge and discharge capacity and voltage values ​​due to their different models. Therefore, a batch of retired batteries of the same model and retired batteries with a discrete distribution of health between 50% and 80% are selected for charge and discharge tests, and the correlation data set between their charge and discharge capacity and voltage value is obtained to replace the correlation data set between the charge and discharge capacity and voltage value of all retired batteries of this model, thereby improving the screening efficiency.

[0033] Step S2, determining the average internal resistance of each retired battery according to the associated data set.

[0034] Specifically, the prior art has problems such as high economic cost, difficulty in application, and time-consuming and labor-intensive, and may also cause damage to retired batteries. In this regard, the average internal resistance of the present application can be directly tested at room temperature through a power battery charge and discharge detection system without the need for additional testing costs and testing instruments, effectively reducing economic costs and causing no secondary damage to retired batteries. The present application is based on an associated data set and determines the average internal resistance of each retired battery by calculation, thereby identifying the average internal resistance in real time online without the need for long-term static or long-term aging, greatly improving efficiency.

[0035] Step S3, performing battery screening according to the average internal resistance of each retired battery.

[0036] Specifically, battery screening based on the average internal resistance of each retired battery can effectively distinguish the different degrees of deterioration of retired battery cells and screen out cells with reduced capacity.

[0037] According to the battery screening method of the embodiment of the present invention, the average internal resistance is introduced to perform consistency screening of retired batteries, that is, the average internal resistance of each retired battery is determined by the correlation data set between the charge and discharge capacity and the voltage value of each retired battery, and the retired batteries can be screened according to the distribution characteristics of the average internal resistance. Therefore, without damaging the retired batteries, the retired batteries can be screened without using complex equipment, thereby reducing economic costs and quickly screening out retired batteries with high consistency for battery reorganization.

[0038] In some embodiments, obtaining a correlation data set between the charge and discharge capacity and the voltage value of each retired battery includes charging and discharging each retired battery at a preset charge and discharge current; obtaining a first correlation data set between the charge capacity and the voltage value of each retired battery within a target voltage range; obtaining a second correlation data set between the discharge capacity and the voltage value of each retired battery within the target voltage range. Specifically, in the power battery charge and discharge test system, each retired battery is charged and discharged with a preset charge and discharge current. After the test is completed, the charge capacity, discharge capacity and voltage value of each retired battery are recorded. By sorting the charge capacity and voltage value of each battery in the target voltage range, the charge capacity-voltage curve, i.e., the first associated data set between the charge capacity and the voltage value, is obtained; by sorting the discharge capacity and voltage value of each battery in the target voltage range, the discharge capacity-voltage curve, i.e., the second associated data set between the discharge capacity and the voltage value, is obtained. Among them, the preset charge and discharge current can be set to 79A, 80A, 81A, etc., and the target voltage range can be set to 2.5V~3.8V, 2.7V~3.8V, etc., and no specific restrictions are made here.

[0039] For example, in the power battery charge and discharge test system, each retired battery is charged and discharged when the preset charge and discharge current is 80A. Taking the charge capacity-voltage curve as an example, Figure 2 As shown, the target voltage segment is V1~V2, and the charging capacity of the target voltage segment V1~V2 is Q C .

[0040] In some embodiments, the average internal resistance of each retired battery is determined based on the associated data set, such as Figure 3 As shown, it includes steps S4 to S7, and the specific steps are as follows.

[0041] Step S4: determining an average charging voltage of each retired battery in a target voltage range according to the first associated data set.

[0042] Specifically, the capacity corresponding to the target voltage range is obtained through the charging capacity-voltage curve of each battery. For example, if the target voltage range is 2.7V~3.8V, the capacity range is 0~Q c , where 0 is the charge capacity at 2.7V, Q c When the charging capacity is 3.8V, the average charging voltage can be obtained by substituting it into formula 1-1, where is the average charging voltage, and the integral is the area under the charging capacity-voltage curve in the target voltage segment.

[0043] Formula 1-1 Step S5: determining the average discharge voltage of each retired battery in the target voltage range according to the second associated data set.

[0044] Specifically, the capacity corresponding to the target voltage range is obtained through the discharge capacity-voltage curve of each battery. For example, if the target voltage range is 3.8V~2.7V, the capacity range is Q d ~0, where 0 is the capacity released at 3.8V, Q d The capacity is released when the voltage is 2.7V. Substituting into formula 1-2, the average discharge voltage can be obtained, where V av,d is the average discharge voltage, and the integral is the area under the capacity-voltage curve in the target voltage segment.

[0045] Formula 1-2 Step S6, calculating the voltage difference between the average charging voltage and the average discharging voltage.

[0046] Specifically, the voltage difference between the average charging voltage and the average discharging voltage can be calculated by formula 1-3: is the voltage difference.

[0047] Formula 1-3 It should be noted that an ideal lithium-ion battery should have a constant average charging voltage and a constant average discharging voltage during its service life. However, after a long period of cycling, the average charging voltage will increase, while the average discharging voltage will decrease. Therefore, the mirror relationship between the average charging voltage and the average discharging voltage can show that the growth of impedance is the most important parameter in the average voltage change, and is reflected by the difference between the average charging voltage and the average discharging voltage. The larger the voltage difference, the greater the growth of the battery impedance.

[0048] Step S7, determining the average internal resistance according to the voltage difference and the preset charge and discharge current.

[0049] Specifically, the voltage difference and the preset charge and discharge current are used to determine the average internal resistance through formula 1-4. Where R is the average internal resistance, I is the preset charge and discharge current Formula 1-4 For example, a 194.7Ah lithium iron phosphate battery was used as the experimental object, and a cycle aging test was performed at a rate of 0.3C at room temperature, with a discharge cut-off voltage of 2.70V and a charge cut-off voltage of 3.8V. Figure 4 As shown, Figure 4It shows the changing trends of the average charging voltage, average discharging voltage and average internal resistance of retired battery cells No. 1 and No. 2 with the same capacity and different aging degrees. The internal aging degree of cell 1 is higher than that of cell 2. Curve 1 shows the changing trend of the average charging voltage of retired battery cell No. 1; Curve 2 shows the changing trend of the average discharging voltage of retired battery cell No. 1; Curve 3 shows the changing trend of the average internal resistance of retired battery cell No. 1; Curve 4 shows the changing trend of the average charging voltage of retired battery cell No. 2; Curve 5 shows the changing trend of the average discharging voltage of retired battery cell No. 2; Curve 6 shows the changing trend of the average internal resistance of retired battery cell No. 2. Figure 3 It can be seen from the dotted box that even if the capacity is the same, the average internal resistance corresponding to the first cycle of retired batteries is significantly different. Therefore, the degree of aging inside the battery can be distinguished by the size of the average internal resistance value. As the cycle aging test continues and the number of cycles increases, the average internal resistance of the No. 2 retired battery cell with a low degree of internal aging tends to be stable, while the average internal resistance of the No. 1 retired battery cell with a high degree of internal aging increases steadily. The difference between the two is obvious, which once again shows that the degree of aging inside the battery can be distinguished by the size of the average internal resistance value.

[0050] In some embodiments, battery screening is performed based on the average internal resistance of each retired battery, including determining a health status value of each retired battery; grouping all retired batteries based on the health status values ​​to obtain multiple battery pre-matching groups; determining an internal resistance screening threshold corresponding to each battery pre-matching group based on the average internal resistance of each retired battery in each battery pre-matching group; and determining a screening result for each battery pre-matching group based on the internal resistance screening threshold.

[0051] Specifically, the health status value reflects the comparison between the current status of the retired battery and that of a brand new one, obtains the health value of each retired battery, and groups all retired batteries according to the health status value of each retired battery. Thus, for retired batteries with different health status values, the internal resistance screening threshold corresponding to each battery pre-matching group can be determined according to the average internal resistance of each retired battery in its battery pre-matching group, and then the retired batteries with different health status values ​​can be screened. At the same time, the retired batteries in each pre-matching group have highly consistent health status values, so that the internal resistance consistency of the retired batteries can be screened in each pre-matching group through the average internal resistance.

[0052] In some embodiments, the state of health value is a capacity value or a SOH value of a retired battery.

[0053] Specifically, the health status value may be the capacity value or SOH value of the retired battery. For example, if the health status value is the capacity value of the retired battery, the health status value of the retired battery may be 150Ah, 190Ah, 230Ah, etc.; or if the health status value is the SOH value of the retired battery, the health status value of the retired battery may be 50%, 60%, 80%, etc. It should be noted that the above health status values ​​may be set according to actual conditions and are not specifically limited here.

[0054] In some embodiments, all retired batteries are grouped according to health status values, including determining multiple preset health status value ranges required for grouping; based on the health status value of each retired battery, retired batteries in the same preset health status value range are grouped as a battery pre-assignment group.

[0055] Specifically, based on the health status value of each retired battery, retired batteries in the same preset health status value range are grouped as a battery pre-matching group, thereby ensuring that the retired batteries in each battery pre-matching group have highly consistent health status values, and the internal resistance consistency of the retired batteries can be screened in the battery pre-matching group.

[0056] Exemplarily, the health status value is explained by taking the capacity value of retired batteries as an example. The retired batteries are grouped according to the capacity value range of 10Ah, and multiple preset health status value ranges are respectively divided into 150-160Ah, 160-170Ah, 170-180Ah, 180-190Ah, 190-200Ah, 200-210Ah, 210-220Ah, and 220-230Ah, and pre-assigned groups are performed based on multiple preset health status value ranges.

[0057] In some embodiments, an internal resistance screening threshold corresponding to each battery pre-matching group is determined based on the average internal resistance of each retired battery in each battery pre-matching group, including determining a median internal resistance value corresponding to each battery pre-matching group based on the average internal resistance of each retired battery in each battery pre-matching group; determining an upper quartile internal resistance value and a lower quartile internal resistance value corresponding to each battery pre-matching group based on the interquartile range method according to the median internal resistance value corresponding to each battery pre-matching group; and using the median internal resistance value, the upper quartile internal resistance value, and the lower quartile internal resistance value as internal resistance screening values.

[0058] Specifically, in practical applications, battery management systems generally use the range of collected single-cell signals to represent the consistency between batteries within the system. However, from a statistical point of view, the range is not the most effective way to represent the discreteness. Therefore, this application uses a box plot to represent the consistency between batteries. Compared with indexes such as standard deviation and mean that describe the degree of data dispersion, the box plot is not affected by outliers, relies on actual data, and does not need to assume that the data obeys a specific distribution form. The results of identifying outliers are more objective.

[0059] For example, Figure 5 As shown, Figure 5 A box plot of the average internal resistance of each pre-configured battery pack is drawn, where the upper quartile internal resistance value is Q3; the lower quartile internal resistance value is Q1; the quartile is IQR; the median internal resistance value of each pre-configured battery pack is connected by a dotted line. As the battery capacity decreases, the median internal resistance gradually increases, which is consistent with the aging law of the battery. Therefore, a box plot can be used to represent the consistency distribution of the battery internal resistance and eliminate anomalies.

[0060] In some embodiments, the screening results of each battery pre-matching group are determined according to the internal resistance screening threshold, including for each battery pre-matching group, the batteries that meet the condition that the average internal resistance value is less than or equal to the lower quartile internal resistance value are regarded as first-category batteries; the batteries that meet the condition that the average internal resistance value is greater than the lower quartile internal resistance value and the average internal resistance value is less than or equal to the median internal resistance value are regarded as second-category batteries; the batteries that meet the condition that the average internal resistance value is greater than the median internal resistance value and the average internal resistance value is less than or equal to the upper quartile internal resistance value are regarded as third-category batteries.

[0061] Specifically, batteries that meet the condition that the average internal resistance value is less than or equal to the lower quartile internal resistance value are classified as first category batteries, and the internal health of first category batteries is excellent; batteries that meet the condition that the average internal resistance value is greater than the lower quartile internal resistance value and the average internal resistance value is less than or equal to the median internal resistance value are classified as second category batteries, and the internal health of second category batteries is good; batteries that meet the condition that the average internal resistance value is greater than the median internal resistance value and the average internal resistance value is less than or equal to the upper quartile internal resistance value are classified as third category batteries, and the internal health of third category batteries is average.

[0062] For example, as shown in Table 1, the consistency of the first type of battery is A, and the internal health is excellent; the consistency of the second type of battery is B, and the internal health is good; the consistency of the third type of battery is C, and the internal health is ordinary.

[0063] Table 1

[0064] In some embodiments, the internal resistance screening value also includes a maximum internal resistance value, and the method further includes determining a preset screening allowable internal resistance value; and calculating the sum of the upper quartile internal resistance value and the preset screening allowable internal resistance value to obtain the maximum internal resistance value.

[0065] Specifically, the maximum value Q MAX It can be obtained through formula 1-5, where Q3 is the upper quartile internal resistance value and 1.5IQR is the screening allowable internal resistance value.

[0066] Formula 1-5 In some embodiments, the screening results of each battery pre-matching group are determined according to the internal resistance screening threshold, and the batteries satisfying the conditions that the average internal resistance value is greater than the upper quartile internal resistance value and the average internal resistance value is less than or equal to the maximum internal resistance value are regarded as fourth category batteries.

[0067] Specifically, batteries that meet the conditions that the average internal resistance value is greater than the upper quartile internal resistance value and the average internal resistance value is less than or equal to the maximum internal resistance value are classified as Category IV batteries. As shown in Table 1, the consistency of Category IV batteries is D, and the internal health condition is poor.

[0068] In some embodiments, the screening result of each battery pre-matching group is determined according to the internal resistance screening threshold, and the batteries satisfying the condition that the average internal resistance value is greater than the maximum internal resistance value are scrapped and recycled.

[0069] Specifically, as shown in Table 1, the internal health of the battery that meets the average internal resistance value greater than the maximum internal resistance value is extremely poor. At this time, the battery has already dived or is about to dive. Such batteries are no longer suitable for re-assembly and cascade utilization and should be discarded and scrapped. As shown in Table 1, the consistency of this type of battery is E, and the internal health is extremely poor. A second embodiment of the present invention provides a battery screening system 100, such as Figure 6 The battery screening system 100 shown includes a data acquisition module 10 , an internal resistance determination module 20 , and a screening module 30 .

[0070] Among them, the data acquisition module 10 is used to obtain the associated data set between the charge and discharge capacity and the voltage value of each retired battery; the internal resistance determination module 20 is used to determine the average internal resistance of each retired battery according to the associated data set; and the screening module 30 is used to screen batteries according to the average internal resistance of each retired battery.

[0071] According to the battery screening system 100 of the embodiment of the present invention, the data set of associations between the charge and discharge capacity and the voltage value of each retired battery acquired by the data acquisition module 10 is sent to the internal resistance determination module 20. The internal resistance determination module 20 determines the average internal resistance of each retired battery through the data set of associations between the charge and discharge capacity and the voltage value of each retired battery, and sends the average internal resistance to the screening module 30, so that the screening module 30 can screen the retired batteries according to the distribution characteristics of the average internal resistance. Therefore, the battery screening system 100 can screen the retired batteries without using complex equipment without damaging the retired batteries, thereby reducing economic costs and being able to quickly screen out retired batteries with high consistency for battery reorganization.

[0072] A third aspect of the present invention provides a computer program product, including a computer program, which implements the steps of the battery screening method of the above embodiment when executed by a processor.

[0073] A fourth embodiment of the present invention provides a battery screening system 100, such as Figure 7 As shown, the battery screening system 100 includes at least one processor 40 and a memory 50 communicatively connected to the at least one processor 40 .

[0074] The memory 40 stores a computer program that can be executed by at least one processor 50 , and the battery screening method of the above embodiment is implemented when the at least one processor 50 executes the computer program.

[0075] According to the battery screening system 100 of the embodiment of the present invention, the processor 50 executes a computer program to implement the battery screening method of the above embodiment. Without damaging the retired batteries, retired batteries can be screened without using complex equipment, thereby reducing economic costs and quickly screening out retired batteries with high consistency for battery reorganization.

[0076] In the description of this specification, any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code including one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0077] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0078] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0079] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0080] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0081] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0083] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery screening method, characterized in that: include: Obtain a correlation data set between the charge and discharge capacity and voltage value of each retired battery; determining an average internal resistance of each retired battery based on the associated data set; Battery screening is performed based on the average internal resistance of each retired battery.

2. The battery screening method according to claim 1, characterized in that: Obtain the correlation data set between the charge and discharge capacity and voltage value of each retired battery, including: charging and discharging each retired battery at a preset charge and discharge current; Acquire a first correlation data set between the charging capacity and the voltage value of each retired battery within the target voltage range; A second correlation data set between the discharge capacity and the voltage value of each retired battery within the target voltage range is obtained.

3. The battery screening method according to claim 2, characterized in that: Determining an average internal resistance of each retired battery according to the associated data set includes: Determine an average charging voltage of each retired battery in the target voltage range according to the first associated data set; determining an average discharge voltage of each retired battery in the target voltage range according to the second associated data set; Calculating a voltage difference between the average charging voltage and the average discharging voltage; The average internal resistance is determined according to the voltage difference and the preset charge and discharge current.

4. The battery screening method according to any one of claims 1 to 3, characterized in that: Battery screening is performed based on the average internal resistance of each retired battery, including: Determine the state of health value of each retired battery; grouping all retired batteries according to the health status values ​​to obtain a plurality of battery pre-assignment groups; Determine the internal resistance screening threshold corresponding to each battery pre-matching group according to the average internal resistance of each retired battery in each battery pre-matching group; The screening result of each battery pre-matching group is determined according to the internal resistance screening threshold.

5. The battery screening method according to claim 4, characterized in that: The health status value is the capacity value or SOH value of the retired battery.

6. The battery screening method according to claim 4, characterized in that: All retired batteries are grouped according to the health status values, including: Determining a plurality of preset health status value ranges required by the grouping; Based on the health status value of each retired battery, retired batteries in the same preset health status value range are grouped as a battery pre-configuration group.

7. The battery screening method according to claim 4, characterized in that: The internal resistance screening threshold corresponding to each battery provisioning group is determined according to the average internal resistance of each retired battery in each battery provisioning group, including: Determine the median internal resistance value corresponding to each battery pre-matching group according to the average internal resistance of each retired battery in each battery pre-matching group; Determine the upper quartile internal resistance value and the lower quartile internal resistance value corresponding to each battery pre-matching group based on the interquartile range method according to the median internal resistance value corresponding to each battery pre-matching group; The median internal resistance value, the upper quartile internal resistance value and the lower quartile internal resistance value are used as the internal resistance screening values.

8. The battery screening method according to claim 7, characterized in that: Determining the screening result of each battery pre-matching group according to the internal resistance screening threshold includes: For each battery pre-matching group, the batteries satisfying the condition that the average internal resistance value is less than or equal to the lower quartile internal resistance value are regarded as first-category batteries; Batteries that meet the conditions that the average internal resistance value is greater than the lower quartile internal resistance value and the average internal resistance value is less than or equal to the median internal resistance value are regarded as second-category batteries; Batteries that meet the conditions that the average internal resistance value is greater than the median internal resistance value and the average internal resistance value is less than or equal to the upper quartile internal resistance value are regarded as third category batteries.

9. The battery screening method according to claim 7 or 8, characterized in that: The internal resistance screening value also includes a maximum internal resistance value, and the method further includes: Determine the preset screening allowable internal resistance value; The sum of the upper quartile internal resistance value and the preset screening allowable internal resistance value is calculated to obtain the maximum internal resistance value.

10. The battery screening method according to claim 9, characterized in that: Determining the screening result of each battery pre-matching group according to the internal resistance screening threshold value also includes: Batteries that meet the conditions that the average internal resistance value is greater than the upper quartile internal resistance value and the average internal resistance value is less than or equal to the maximum internal resistance value are regarded as fourth category batteries.

11. The battery screening method according to claim 9, characterized in that: Determining the screening result of each battery pre-matching group according to the internal resistance screening threshold value also includes: Batteries that meet the condition that the average internal resistance value is greater than the maximum internal resistance value will be scrapped and recycled.

12. A battery screening system, characterized in that: include: A data acquisition module, used to acquire a correlation data set between the charge and discharge capacity and the voltage value of each retired battery; an internal resistance determination module, configured to determine an average internal resistance of each retired battery according to the associated data set; A screening module is used to screen batteries based on the average internal resistance of each retired battery.

13. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the battery screening method according to any one of claims 1 to 11 are implemented.

14. A battery screening system, characterized in that: include: at least one processor; a memory communicatively coupled to at least one of the processors; The memory stores a computer program executable by at least one of the processors, and when at least one of the processors executes the computer program, the battery screening method according to any one of claims 1 to 11 is implemented.

Images