CN114264969B - Method and device for evaluating self-discharge performance of battery cell - Google Patents
Method and device for evaluating self-discharge performance of battery cell Download PDFInfo
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- CN114264969B CN114264969B CN202111576938.4A CN202111576938A CN114264969B CN 114264969 B CN114264969 B CN 114264969B CN 202111576938 A CN202111576938 A CN 202111576938A CN 114264969 B CN114264969 B CN 114264969B
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Abstract
The invention provides a method and a device for evaluating self-discharge performance of a battery cell, wherein the method comprises the following steps: obtaining rated capacity corresponding to each battery cell to be evaluated; after each battery cell to be evaluated is adjusted to the same set charge state, carrying out voltage equalization on each battery cell to be evaluated to obtain an equalized voltage value; respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value, and calculating the self-discharge capacity of each battery cell to be evaluated; and carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated. The self-discharge capacity of each battery cell is obtained by calculating the constant voltage charge mode of the battery cells in the specified state of charge (SOC state), the rated capacity and the self-discharge capacity of each battery cell are comprehensively considered to evaluate the self-discharge performance of each battery cell, an accurate data basis is provided for screening and matching the battery cells, the consistency of the batteries after matching is further improved, and the battery performance is guaranteed.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a method and a device for evaluating self-discharge performance of a battery cell.
Background
The self-discharge process of lithium ion batteries can exacerbate the inconsistency of lithium ion batteries, ultimately leading to accelerated degradation of battery contents. Therefore, before the battery module or the battery pack is prepared, the self-discharge performance of each battery core is required to be evaluated, the battery core with high self-discharge rate is screened out, and the influence of the self-discharge of the battery core on the service life of the module or the battery pack is reduced to the greatest extent. Current methods for evaluating the self-discharge performance of batteries are all by observing the voltage change in the open circuit state. For example, the battery cell is discharged to soc=0, then the battery cell is stored in different ambient temperatures, the change condition of the voltage value of the battery cell and the storage time are recorded, and the self-discharge rate of the battery is calculated through the change of the voltage and the storage time, and the evaluation method often needs to wait for a long time to observe the significant change of the voltage. And because the polarization of the battery is very serious at low SOC, the observed voltage rise difference can be caused by the difference of polarization potentials, so that the accuracy of the battery self-discharge rate calculation result is influenced, and the accuracy of the final battery self-discharge performance evaluation result is further influenced.
Disclosure of Invention
Therefore, the embodiment of the invention provides a method and a device for evaluating the self-discharge performance of a battery cell, so as to solve the problem of low accuracy of the method for evaluating the self-discharge performance of the battery in the prior art.
The embodiment of the invention provides a method for evaluating the self-discharge performance of a battery cell, which comprises the following steps:
obtaining rated capacity corresponding to each battery cell to be evaluated;
after each battery cell to be evaluated is adjusted to the same set charge state, carrying out voltage equalization on each battery cell to be evaluated to obtain an equalized voltage value;
respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value, and calculating the self-discharge capacity of each battery cell to be evaluated;
and carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated.
Optionally, the obtaining the rated capacity corresponding to each cell to be evaluated includes:
charging the current battery cell to be evaluated to a charging cut-off voltage by a first current value respectively, and then charging the current battery cell to be evaluated to a second current value by the charging cut-off voltage, wherein the first current value is larger than the second current value;
discharging the current battery cell to be evaluated to a discharge cut-off voltage respectively at a first current value, and recording constant-current discharge capacity;
and determining the rated capacity corresponding to the current battery cell to be evaluated based on the constant-current discharge capacity.
Optionally, the constant voltage charging is performed on each battery cell to be evaluated by using the balanced voltage value, and the calculating of the self-discharge capacity of each battery cell to be evaluated includes:
constant voltage charging is carried out on the current battery cell to be evaluated according to the balanced voltage value, and real-time charging current is recorded;
and after the charging time reaches the set constant-voltage charging time, calculating the self-discharge capacity of the current battery cell to be evaluated based on the relation between the real-time charging current and the charging time.
Optionally, the self-discharge performance evaluation is performed based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated, to obtain a self-discharge performance evaluation result of each battery cell to be evaluated, including:
calculating average rated capacity based on the rated capacity corresponding to each battery cell to be evaluated;
calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each cell to be evaluated;
calculating rated capacity deviation of the current battery cell to be evaluated based on the relation between the rated capacity corresponding to the current battery cell to be evaluated and the average rated capacity;
calculating the self-discharge capacity deviation of the current battery cell to be evaluated based on the relation between the self-discharge capacity corresponding to the current battery cell to be evaluated and the average self-discharge capacity;
and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated.
Optionally, the determining, based on the rated capacity deviation and the self-discharge capacity deviation of the current to-be-evaluated battery cell, a self-discharge performance evaluation result corresponding to the current to-be-evaluated battery cell includes:
calculating a consistency evaluation value of the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated;
and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the relationship between the consistency evaluation value and a preset evaluation threshold range.
Optionally, the determining, based on the relationship between the consistency evaluation value and a preset evaluation threshold range, a self-discharge performance evaluation result corresponding to the current to-be-evaluated battery cell includes:
judging whether the consistency evaluation value is within the preset evaluation threshold range or not;
when the consistency evaluation value is within the preset evaluation threshold value range, determining that the self-discharge performance evaluation result corresponding to the current to-be-evaluated battery cell is that the current to-be-evaluated battery cell meets the battery consistency requirement;
and when the consistency evaluation value is not in the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery cell to be evaluated is that the current battery cell to be evaluated does not meet the battery consistency requirement.
Optionally, the method further comprises:
and eliminating the battery cells to be evaluated which do not meet the requirement of battery consistency.
The embodiment of the invention also provides a device for evaluating the self-discharge performance of the battery cell, which comprises the following steps:
the acquisition module is used for acquiring rated capacity corresponding to each battery cell to be evaluated;
the first processing module is used for carrying out voltage equalization on each battery cell to be evaluated after the battery cells to be evaluated are adjusted to the same set charge state, so as to obtain an equalized voltage value;
the second processing module is used for respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value and calculating the self-discharge capacity of each battery cell to be evaluated;
and the third processing module is used for carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated, and obtaining a self-discharge performance evaluation result of each battery cell to be evaluated.
The embodiment of the invention also provides electronic equipment, which comprises: the device comprises a memory and a processor, wherein the memory and the processor are in communication connection, the memory stores computer instructions, and the processor executes the computer instructions so as to execute the method provided by the embodiment of the invention.
The embodiment of the invention also provides a computer readable storage medium, which stores computer instructions for causing the computer to execute the method provided by the embodiment of the invention.
The technical scheme of the invention has the following advantages:
the embodiment of the invention provides a method and a device for evaluating self-discharge performance of a battery cell, which are implemented by acquiring rated capacity corresponding to each battery cell to be evaluated; after each battery cell to be evaluated is adjusted to the same set charge state, carrying out voltage equalization on each battery cell to be evaluated to obtain an equalized voltage value; respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value, and calculating the self-discharge capacity of each battery cell to be evaluated; and carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated. The self-discharge capacity of each battery cell is obtained by calculating the constant voltage charge mode of the battery cell in the specified state of charge (SOC state), the rated capacity and the self-discharge capacity of each battery cell are comprehensively considered to evaluate the self-discharge performance of each battery cell, an accurate data basis is provided for screening and matching the battery cells, the consistency of the battery after matching is further improved, the battery performance is ensured, and in addition, the self-discharge capacity of the battery cell at any temperature, in any SOC state and in any time can be rapidly and accurately obtained, and the calculation efficiency of the self-discharge capacity is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flowchart of a method for evaluating self-discharge performance of a battery cell according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of current evolution during constant voltage charging of different cells according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing distribution of the self-discharge outlier judgment factors of the battery cells according to an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a specific working process of evaluating the self-discharge performance of the battery cell according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a device for evaluating self-discharge performance of a battery cell according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of 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, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.
The technical features of the different embodiments of the invention described below may be combined with one another as long as they do not conflict with one another.
The self-discharge process of lithium ion batteries can exacerbate the inconsistency of lithium ion batteries, ultimately leading to accelerated degradation of battery contents. Therefore, before the battery module or the battery pack is prepared, the self-discharge performance of each battery core is required to be evaluated, the battery core with high self-discharge rate is screened out, and the influence of the self-discharge of the battery core on the service life of the module or the battery pack is reduced to the greatest extent. Current methods for evaluating the self-discharge performance of batteries are all by observing the voltage change in the open circuit state. For example, the battery cell is discharged to soc=0, then the battery cell is stored in different ambient temperatures, the change condition of the voltage value of the battery cell and the storage time are recorded, and the self-discharge rate of the battery is calculated through the change of the voltage and the storage time, and the evaluation method often needs to wait for a long time to observe the significant change of the voltage. And because the polarization of the battery is very serious at low SOC, the observed voltage rise difference can be caused by the difference of polarization potentials, so that the accuracy of the battery self-discharge rate calculation result is influenced, and the accuracy of the final battery self-discharge performance evaluation result is further influenced.
Based on the above-mentioned problems, the embodiment of the present invention provides a method for evaluating self-discharge performance of a battery cell, as shown in fig. 1, which specifically includes the following steps:
step S101: and obtaining the rated capacity corresponding to each battery cell to be evaluated.
The rated capacity in the embodiment of the present invention is an actual capacity value of the battery cell, and in practical application, the actual rated capacities of different battery cells may be different from the nominal capacities of the battery cells, for example: the nominal capacities of the A battery cell and the B battery cell are 100Ah, the actual rated capacity of the A battery cell is 105Ah, the actual rated capacity of the B battery cell may be 95Ah, and the like. In this embodiment, the total number of the cells to be evaluated is taken as N as an example.
Step S102: and after the electric cores to be evaluated are adjusted to the same set charge state, carrying out voltage equalization on the electric cores to be evaluated to obtain an equalized voltage value.
The set state of charge (SOC) can be selected according to the type of the battery, for example, when the battery core is a lithium iron phosphate system (LFP system), the SOC can only take a section corresponding to a region with obvious voltage slope change so as to ensure the accuracy of a final evaluation result; and when the battery core is a ternary nickel-cobalt-manganese system, namely an NCM system, the SOC can take any value, and the final evaluation result is not influenced.
Specifically, the voltages of the N cells to be evaluated can be equalized by a voltage equalization device so that the voltages reach the same value, and the value is recorded as V.
Step S103: and respectively carrying out constant voltage charging on each battery cell to be evaluated by using the balanced voltage value, and calculating the self-discharge capacity of each battery cell to be evaluated.
Specifically, each cell is subjected to constant voltage charging under the voltage V, after the charging is performed for h hours, the relationship between the current and the charging time of the constant voltage charging of each cell is recorded, and the self-discharge capacity corresponding to the cell is obtained through calculation according to the relationship between the current and the charging time of the constant voltage charging of the cell.
Step S104: and carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated.
Specifically, through analyzing rated capacity and self-discharge capacity corresponding to each battery cell to be evaluated, a battery cell self-discharge outlier judgment factor is obtained, and further, the self-discharge consistency of the battery cells is accurately evaluated according to the specific numerical value of the battery cell self-discharge outlier judgment factor.
By executing the steps, the self-discharge performance evaluation method of the battery cells provided by the embodiment of the invention calculates the self-discharge capacity of each battery cell by carrying out constant voltage charging on the battery cells in a specified state of charge (SOC state), and comprehensively considers the rated capacity and the self-discharge capacity of each battery cell to evaluate the self-discharge performance of each battery cell, thereby providing an accurate data basis for screening and assembling the battery cells, further improving the consistency of assembled batteries, guaranteeing the performance of the batteries, and further rapidly and accurately acquiring the self-discharge capacity of the battery cells at any temperature, in any SOC state and in any time, and improving the calculation efficiency of the self-discharge capacity.
Specifically, in an embodiment, the step S101 specifically includes the following steps:
step S201: and respectively charging the current battery cell to be evaluated to a charging cut-off voltage at a first current value, and then charging the current battery cell to be evaluated to a charging current reaching a second current value at the charging cut-off voltage.
Wherein the first current value is greater than the second current value. The second current value is a current value for determining that the charging of the battery cell is completed, for example: 0.05C, etc. The first current value is 1/3C, which is only an example and not a limitation of the present invention.
Step S202: and discharging the current battery cells to be evaluated to a discharge cut-off voltage respectively at a first current value, and recording the constant-current discharge capacity.
Specifically, for the cells with the same specification, the discharge cut-off voltages are the same, and in the embodiment of the present invention, the discharge cut-off voltages of the N cells to be evaluated are the same, and the values of the specific discharge cut-off voltages are related to the types of the cells to be evaluated, which is not described herein.
Step S203: and determining the rated capacity corresponding to the current battery cell to be evaluated based on the constant-current discharge capacity.
Illustratively, by charging the cell to a cutoff voltage at a constant current of 1/3C at ambient temperature T, the constant voltage charge is turned to a current of 0.05C; standing for 0.5 hrThe constant-current discharge of 1/3C to the discharge cut-off voltage is recorded, and the recorded constant-current discharge capacity is the rated capacity Q of the battery cell i Wherein i represents the number of the cell to be identified. Therefore, the actual capacity of each battery cell to be identified can be accurately obtained by calibrating the rated capacity of the battery cell, and the accuracy of the final battery cell self-discharge performance evaluation result is further improved.
Specifically, in one embodiment, the step S103 specifically includes the following steps:
step S301: and carrying out constant voltage charging on the current to-be-evaluated battery cell by using the balanced voltage value, and recording real-time charging current.
Step S302: and after the charging time reaches the set constant-voltage charging time, calculating the self-discharge capacity of the current battery cell to be evaluated based on the relation between the real-time charging current and the charging time.
Illustratively, each cell is charged at constant voltage at the above voltage V at ambient temperature T, and after h hours of charging, the current of each cell for constant voltage charging is recorded. It should be noted that the current collection interval of the constant voltage charging device should be less than 10 milliamperes to ensure the accuracy of current collection. FIG. 2 is a schematic diagram showing the current evolution of each cell during constant voltage charging, where j i The current change curve of the ith cell to be evaluated is shown. According to the charging current j i The integral of the charge time t can be used for calculating the self-discharge capacity of the ith battery cell, namely the self-discharge capacity of the battery cell in the specified SoC, the specified temperature and the specified time.
Therefore, through carrying out voltage equalizing treatment on each battery cell and then carrying out constant voltage charging on the voltage value after voltage equalizing, the self-discharge capacity of each battery cell can be obtained to directly reflect the difference of the self-discharge performance of each battery cell, and the accuracy of the final battery cell self-discharge performance evaluation result is further improved.
Specifically, in an embodiment, the step S104 specifically includes the following steps:
step S401: and calculating the average rated capacity based on the rated capacity corresponding to each cell to be evaluated.
Specifically, the average rated capacity can be calculated by the following formula (1):
wherein, the liquid crystal display device comprises a liquid crystal display device,represents average rated capacity, N represents the number of cells to be evaluated, i represents the number of cells to be evaluated, Q i And the rated capacity corresponding to the ith battery cell to be evaluated is represented.
Step S402: based on the self-discharge capacity corresponding to each cell to be evaluated, the average self-discharge capacity is calculated.
Specifically, the average self-discharge capacity can be calculated by the following formula (2):
wherein, the liquid crystal display device comprises a liquid crystal display device,represents the average self-discharge capacity, N represents the number of cells to be evaluated, i represents the number of cells to be evaluated,/->And the self-discharge capacity corresponding to the ith battery cell to be evaluated is shown.
Step S403: and calculating the rated capacity deviation of the current battery cell to be evaluated based on the relation between the rated capacity corresponding to the current battery cell to be evaluated and the average rated capacity.
Specifically, the rated capacity deviation can be calculated by the following formula (3):
wherein delta i Indicating the deviation of rated capacity of each cell to be evaluated at the ith,represents average rated capacity, Q i And the rated capacity corresponding to the ith battery cell to be evaluated is represented.
Step S404: and calculating the self-discharge capacity deviation of the current battery cell to be evaluated based on the relation between the self-discharge capacity corresponding to the current battery cell to be evaluated and the average self-discharge capacity.
Specifically, the self-discharge capacity deviation can be calculated by the following formula (4):
wherein sigma i Indicating the deviation of the self-discharge capacity of each cell to be evaluated,mean self-discharge capacity,/->And the self-discharge capacity corresponding to the ith battery cell to be evaluated is shown.
Step S405: and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated.
Specifically, in an embodiment, the step S405 specifically includes the following steps:
step S51: and calculating the consistency evaluation value of the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated.
Specifically, the consistency evaluation value can be calculated by the following formula (5):
wherein ε i Consistency evaluation indicating the ith cell to be evaluatedValue, i.e. cell self-discharge outlier judgment factor, sigma i Representing the deviation delta of the self-discharge capacity of each cell to be evaluated i Indicating the rated capacity deviation of each ith battery cell to be evaluated.
Step S52: and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the relationship between the consistency evaluation value and the preset evaluation threshold range.
Specifically, step S52 above is specifically performed by determining whether the consistency evaluation value is within a preset evaluation threshold range; when the consistency evaluation value is within a preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery cell to be evaluated is that the current battery cell to be evaluated meets the battery consistency requirement; when the consistency evaluation value is not in the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery cell to be evaluated is that the current battery cell to be evaluated does not meet the battery consistency requirement.
Exemplary, the distribution diagram of the consistency evaluation values of the N cells, i.e. the cell self-discharge outlier judgment factors, is shown in FIG. 3, when ε i When more than 1, the self-discharge rate of the battery cell is higher, otherwise epsilon i <1, the self-discharge rate of the battery cell is lower; if epsilon i The self-discharge rate of each cell is completely consistent, and only parameters such as capacity, internal resistance and the like need to be considered when the cells are assembled, and the self-discharge rate does not need to be considered. In practice, epsilon for each cell i The values are all floating up and down at 1, so that a preset evaluation threshold range can be flexibly set according to the actual battery matching requirement to screen the battery cells.
Specifically, when 0.99<ε i <1.01, the self-discharge consistency of the battery cells is considered to be good, and the battery cells can be used for matching battery packs or batteries. In practical application, as long as epsilon i The battery cells with the value within +/-0.01 can be used for matching, but epsilon is generally selected when the battery cells are matched in consideration of the fact that the service life of the battery cells can be influenced by the too high self-discharge rate i <1.01, by way of example only, and the invention is not limited thereto.
Therefore, through calculating the consistency evaluation value of each battery cell to be evaluated, the battery cells are screened, classified and assembled, so that the battery or battery pack with better consistency performance can be obtained, the stability of the battery or battery pack is further improved, the service life is prolonged, and the user experience is improved.
Specifically, in an embodiment, the method for evaluating the self-discharge performance of the battery cell specifically further includes the following steps:
step S105: and eliminating the battery cells to be evaluated which do not meet the requirement of battery consistency.
Specifically, when the battery selects the battery core for matching, the better the consistency of the self-discharge performance among the battery cores is, the better the consistency of the battery is, therefore, when the battery is matched, the battery core to be evaluated which does not meet the requirement of the consistency of the battery is removed, thereby the consistency of the battery can be ensured by selecting the battery core for matching the battery pack or the battery in the rest battery cores, the problem of the accelerated decline of the battery inclusion is avoided, the stability of the battery or the battery pack is improved, and the user experience is improved.
As shown in fig. 4, by the method for evaluating the self-discharge performance of the battery core provided by the embodiment of the invention, the self-discharge capacity of the battery core at any temperature, in any SOC state and in any time can be rapidly and accurately obtained, the self-discharge rate of the battery core is rapidly evaluated according to the self-discharge outlier judgment factor of each battery core, and the battery core is screened and assembled by setting the reasonable self-discharge outlier judgment factor, so that an accurate data basis is provided for improving the battery performance, prolonging the service life of the battery and improving the user experience.
By executing the steps, the self-discharge performance evaluation method of the battery cells provided by the embodiment of the invention calculates the self-discharge capacity of each battery cell by carrying out constant voltage charging on the battery cells in a specified state of charge (SOC state), and comprehensively considers the rated capacity and the self-discharge capacity of each battery cell to evaluate the self-discharge performance of each battery cell, thereby providing an accurate data basis for screening and assembling the battery cells, further improving the consistency of assembled batteries, guaranteeing the performance of the batteries, and further rapidly and accurately acquiring the self-discharge capacity of the battery cells at any temperature, in any SOC state and in any time, and improving the calculation efficiency of the self-discharge capacity.
The embodiment of the invention also provides a device for evaluating the self-discharge performance of the battery cell, as shown in fig. 5, which comprises:
and the acquisition module 101 is used for acquiring the rated capacity corresponding to each cell to be evaluated. For details, refer to the related description of step S101 in the above method embodiment, and no further description is given here.
The first processing module 102 is configured to adjust each to-be-evaluated battery cell to the same set state of charge, and then perform voltage equalization on each to-be-evaluated battery cell to obtain an equalized voltage value. For details, refer to the related description of step S102 in the above method embodiment, and no further description is given here.
And the second processing module 103 is used for respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value and calculating the self-discharge capacity of each battery cell to be evaluated. For details, see the description of step S103 in the above method embodiment, and the details are not repeated here.
And the third processing module 104 is configured to perform self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated, so as to obtain a self-discharge performance evaluation result of each battery cell to be evaluated. For details, refer to the related description of step S104 in the above method embodiment, and no further description is given here.
Through the cooperation of the above components, the self-discharge performance evaluation device for the battery cells provided by the embodiment of the invention calculates the self-discharge capacity of each battery cell by performing constant voltage charging on the battery cells in a specified charge state, namely in an SOC state, comprehensively considers the rated capacity and the self-discharge capacity of each battery cell to evaluate the self-discharge performance of each battery cell, provides an accurate data base for screening and assembling the battery cells, further improves the consistency of assembled batteries, ensures the battery performance, and can rapidly and accurately acquire the self-discharge capacity of the battery cells at any temperature, at any SOC state and in any time, thereby improving the calculation efficiency of the self-discharge capacity.
Further functional descriptions of the above respective modules are the same as those of the above corresponding method embodiments, and are not repeated here.
There is also provided in accordance with an embodiment of the present invention, an electronic device, as shown in fig. 6, which may include a processor 901 and a memory 902, wherein the processor 901 and the memory 902 may be connected via a bus or otherwise, as exemplified by the bus connection in fig. 6.
The processor 901 may be a central processing unit (Central Processing Unit, CPU). The processor 901 may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination thereof.
The memory 902 is used as a non-transitory computer readable storage medium for storing non-transitory software programs, non-transitory computer executable programs, and modules, such as program instructions/modules corresponding to the methods in the method embodiments of the present invention. The processor 901 executes various functional applications of the processor and data processing, i.e., implements the methods in the above-described method embodiments, by running non-transitory software programs, instructions, and modules stored in the memory 902.
The memory 902 may include a storage program area and a storage data area, wherein the storage program area may store an operating device, at least one application program required for a function; the storage data area may store data created by the processor 901, and the like. In addition, the memory 902 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 902 optionally includes memory remotely located relative to processor 901, which may be connected to processor 901 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
One or more modules are stored in the memory 902 that, when executed by the processor 901, perform the methods of the method embodiments described above.
The specific details of the electronic device may be correspondingly understood by referring to the corresponding related descriptions and effects in the above method embodiments, which are not repeated herein.
It will be appreciated by those skilled in the art that implementing all or part of the above-described embodiment method may be implemented by a computer program to instruct related hardware, and the program may be stored in a computer readable storage medium, and the program may include the above-described embodiment method when executed. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), or a Solid State Drive (SSD); the storage medium may also comprise a combination of memories of the kind described above.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations are within the scope of the invention as defined by the appended claims.
Claims (9)
1. The method for evaluating the self-discharge performance of the battery cell is characterized by comprising the following steps of:
obtaining rated capacity corresponding to each battery cell to be evaluated;
after each battery cell to be evaluated is adjusted to the same set charge state, carrying out voltage equalization on each battery cell to be evaluated to obtain an equalized voltage value;
respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value, and calculating the self-discharge capacity of each battery cell to be evaluated;
performing self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated;
the self-discharge performance evaluation is performed based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated, so as to obtain a self-discharge performance evaluation result of each battery cell to be evaluated, and the self-discharge performance evaluation result comprises:
calculating average rated capacity based on the rated capacity corresponding to each battery cell to be evaluated;
calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each cell to be evaluated;
calculating rated capacity deviation of the current battery cell to be evaluated based on the relation between the rated capacity corresponding to the current battery cell to be evaluated and the average rated capacity;
calculating the self-discharge capacity deviation of the current battery cell to be evaluated based on the relation between the self-discharge capacity corresponding to the current battery cell to be evaluated and the average self-discharge capacity;
and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated.
2. The method of claim 1, wherein the obtaining the rated capacity corresponding to each cell to be evaluated comprises:
charging the current battery cell to be evaluated to a charging cut-off voltage by a first current value respectively, and then charging the current battery cell to be evaluated to a second current value by the charging cut-off voltage, wherein the first current value is larger than the second current value;
discharging the current battery cell to be evaluated to a discharge cut-off voltage respectively at a first current value, and recording constant-current discharge capacity;
and determining the rated capacity corresponding to the current battery cell to be evaluated based on the constant-current discharge capacity.
3. The method of claim 1, wherein the constant voltage charging is performed on each of the cells to be evaluated at the balanced voltage value, and calculating the self-discharge capacity of each of the cells to be evaluated comprises:
constant voltage charging is carried out on the current battery cell to be evaluated according to the balanced voltage value, and real-time charging current is recorded;
and after the charging time reaches the set constant-voltage charging time, calculating the self-discharge capacity of the current battery cell to be evaluated based on the relation between the real-time charging current and the charging time.
4. The method of claim 1, wherein the determining the self-discharge performance evaluation result corresponding to the current cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current cell to be evaluated comprises:
calculating a consistency evaluation value of the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated;
and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the relationship between the consistency evaluation value and a preset evaluation threshold range.
5. The method of claim 4, wherein the determining the self-discharge performance evaluation result corresponding to the current cell to be evaluated based on the relationship between the consistency evaluation value and a preset evaluation threshold range comprises:
judging whether the consistency evaluation value is within the preset evaluation threshold range or not;
when the consistency evaluation value is within the preset evaluation threshold value range, determining that the self-discharge performance evaluation result corresponding to the current to-be-evaluated battery cell is that the current to-be-evaluated battery cell meets the battery consistency requirement;
and when the consistency evaluation value is not in the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery cell to be evaluated is that the current battery cell to be evaluated does not meet the battery consistency requirement.
6. The method as recited in claim 5, further comprising:
and eliminating the battery cells to be evaluated which do not meet the requirement of battery consistency.
7. A cell self-discharge performance evaluation device, comprising:
the acquisition module is used for acquiring rated capacity corresponding to each battery cell to be evaluated;
the first processing module is used for carrying out voltage equalization on each battery cell to be evaluated after the battery cells to be evaluated are adjusted to the same set charge state, so as to obtain an equalized voltage value;
the second processing module is used for respectively carrying out constant voltage charging on each battery cell to be evaluated according to the balanced voltage value and calculating the self-discharge capacity of each battery cell to be evaluated;
the third processing module is used for carrying out self-discharge performance evaluation based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain a self-discharge performance evaluation result of each battery cell to be evaluated; the self-discharge performance evaluation is performed based on the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated, so as to obtain a self-discharge performance evaluation result of each battery cell to be evaluated, and the self-discharge performance evaluation result comprises: calculating average rated capacity based on the rated capacity corresponding to each battery cell to be evaluated; calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each cell to be evaluated; calculating rated capacity deviation of the current battery cell to be evaluated based on the relation between the rated capacity corresponding to the current battery cell to be evaluated and the average rated capacity; calculating the self-discharge capacity deviation of the current battery cell to be evaluated based on the relation between the self-discharge capacity corresponding to the current battery cell to be evaluated and the average self-discharge capacity; and determining a self-discharge performance evaluation result corresponding to the current battery cell to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery cell to be evaluated.
8. An electronic device, comprising:
a memory and a processor, the memory and the processor being communicatively coupled to each other, the memory having stored therein computer instructions, the processor executing the computer instructions to perform the method of any of claims 1-6.
9. A computer readable storage medium having stored thereon computer instructions for causing the computer to perform the method of any one of claims 1-6.
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