CN114264969A - 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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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: acquiring the rated capacity corresponding to each battery cell to be evaluated; after adjusting the electric cores to be evaluated to the same set charge state, carrying out voltage equalization on the electric cores 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 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 the self-discharge performance evaluation result of each battery cell to be evaluated. Therefore, the self-discharge capacity of each battery cell is calculated by carrying out constant-voltage charging on the battery cells in a specified charge state (namely SOC state), the self-discharge performance of each battery cell is evaluated by comprehensively considering the rated capacity and the self-discharge capacity of each battery cell, an accurate data base is provided for screening and matching of the battery cells, the consistency of the matched batteries 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 core.
Background
The lithium ion battery self-discharge process can aggravate the inconsistency of the lithium ion battery, and finally the battery capacity is accelerated to decline. Therefore, before preparing a battery module or a battery pack, the self-discharge performance of each battery cell needs to be evaluated, the battery cells with high self-discharge rate are screened out, and the influence of the self-discharge of the battery cells on the service life of the module or the battery pack is reduced to the greatest extent. The current methods for evaluating the self-discharge performance of the battery are all by observing the voltage change in the open circuit state. For example, discharging the cell to SOC of 0, storing the cell in different ambient temperatures, recording the change of the cell voltage value and the storage time, and calculating the self-discharge rate of the battery according to the change of the voltage and the storage time, such an 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 when the SOC is low, the observed voltage rise-back difference is also possibly caused by the difference of the polarization potentials of the battery, so that the accuracy of the calculation result of the self-discharge rate of the battery is influenced, and the accuracy of the final self-discharge performance evaluation result of the battery is further influenced.
Disclosure of Invention
In view of this, embodiments of the present invention provide a method and an apparatus for evaluating a self-discharge performance of a battery cell, so as to overcome the problem of low accuracy of a method for evaluating a self-discharge performance of a battery in the prior art.
The embodiment of the invention provides a method for evaluating self-discharge performance of a battery cell, which comprises the following steps:
acquiring the rated capacity corresponding to each battery cell to be evaluated;
after adjusting the electric cores to be evaluated to the same set charge state, carrying out voltage equalization on the electric cores 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 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 the self-discharge performance evaluation result of each battery cell to be evaluated.
Optionally, the obtaining of the rated capacity corresponding to each to-be-evaluated electric core includes:
respectively charging the current battery cell to be evaluated to a charging cut-off voltage by a first current value, 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 at a first current value respectively, 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 performing constant-voltage charging on each to-be-evaluated battery cell by using the equalization voltage value, and calculating the self-discharge capacity of each to-be-evaluated battery cell includes:
carrying out constant voltage charging on the current battery cell to be evaluated according to the balanced voltage value, and recording real-time charging current;
and after the charging time reaches the set constant voltage charging time, calculating the self-discharging 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, so as to obtain a self-discharge performance evaluation result of each battery cell to be evaluated, where the self-discharge performance evaluation result includes:
calculating the average rated capacity based on the rated capacity corresponding to each electric core to be evaluated;
calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each electric core to be evaluated;
calculating the rated capacity deviation of the current battery core to be evaluated based on the relation between the rated capacity corresponding to the current battery core to be evaluated and the average rated capacity;
calculating the self-discharge capacity deviation of the current to-be-evaluated battery cell based on the relation between the self-discharge capacity corresponding to the current to-be-evaluated battery cell 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 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 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 relation between the consistency evaluation value and a preset evaluation threshold range.
Optionally, the 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 includes:
judging whether the consistency evaluation value is within the preset evaluation threshold range;
when the consistency evaluation value is within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery core to be evaluated meets the requirement of battery consistency of the current battery core to be evaluated;
and when the consistency evaluation value is not within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery core to be evaluated does not meet the requirement of battery consistency.
Optionally, the method further comprises:
and rejecting the battery cell to be evaluated which does not meet the requirement of battery consistency.
The embodiment of the present invention further provides a device for evaluating self-discharge performance of a battery cell, including:
the acquisition module is used for acquiring the rated capacity corresponding to each electric core to be evaluated;
the first processing module is used for adjusting the electric cores to be evaluated to the same set charge state and then carrying out voltage equalization on the electric cores to be evaluated 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 on the basis of the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain the self-discharge performance evaluation result of each battery cell to be evaluated.
An embodiment of the present invention further provides an electronic device, including: the device comprises a memory and a processor, wherein the memory and the processor are connected with each other in a communication mode, computer instructions are stored in the memory, 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 enabling a 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 the self-discharge performance of a battery cell, wherein the rated capacity corresponding to each battery cell to be evaluated is obtained; after adjusting the electric cores to be evaluated to the same set charge state, carrying out voltage equalization on the electric cores 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 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 the self-discharge performance evaluation result of each battery cell to be evaluated. Therefore, the self-discharge capacity of each battery cell is calculated by carrying out constant-voltage charging on the battery cells in a specified charge state (namely SOC state), the self-discharge performance of each battery cell is evaluated by comprehensively considering the rated capacity and the self-discharge capacity of each battery cell, an accurate data base is provided for screening and matching of the battery cells, the consistency of the battery after matching is further improved, the performance of the battery is ensured, in addition, the self-discharge capacity of the battery cells 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 used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a method for evaluating a 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 battery cells in the embodiment of the present invention;
fig. 3 is a schematic diagram illustrating distribution of cell self-discharge outlier determination factors according to an embodiment of the present disclosure;
fig. 4 is a schematic diagram of a specific working process of evaluating self-discharge performance of a battery cell in an embodiment of the invention;
fig. 5 is a schematic structural diagram of a cell self-discharge performance evaluation apparatus in an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an electronic device in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.
The lithium ion battery self-discharge process can aggravate the inconsistency of the lithium ion battery, and finally the battery capacity is accelerated to decline. Therefore, before preparing a battery module or a battery pack, the self-discharge performance of each battery cell needs to be evaluated, the battery cells with high self-discharge rate are screened out, and the influence of the self-discharge of the battery cells on the service life of the module or the battery pack is reduced to the greatest extent. The current methods for evaluating the self-discharge performance of the battery are all by observing the voltage change in the open circuit state. For example, discharging the cell to SOC of 0, storing the cell in different ambient temperatures, recording the change of the cell voltage value and the storage time, and calculating the self-discharge rate of the battery according to the change of the voltage and the storage time, such an 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 when the SOC is low, the observed voltage rise-back difference is also possibly caused by the difference of the polarization potentials of the battery, so that the accuracy of the calculation result of the self-discharge rate of the battery is influenced, and the accuracy of the final self-discharge performance evaluation result of the battery is further influenced.
Based on the above problem, an embodiment of the present invention provides a method for evaluating a self-discharge performance of a battery cell, as shown in fig. 1, where the method specifically includes the following steps:
step S101: and acquiring the rated capacity corresponding to each battery cell to be evaluated.
In practical application, the actual rated capacities of different battery cells may be different from the nominal capacities of the battery cells, such as: the nominal capacity of the battery cell A and the nominal capacity of the battery cell B are both 100Ah, the actual rated capacity of the battery cell A is 105Ah, and the actual rated capacity of the battery cell B may be 95 Ah. In this embodiment, a description is given by taking the total number of the cells to be evaluated as N as an example.
Step S102: and after the electric cores to be evaluated are adjusted to the same set charge state, voltage equalization is carried out on the electric cores to be evaluated, and an equalized voltage value is obtained.
The set state of charge, namely SOC, can be selected according to the type of the battery, for example, when the battery cell is a lithium iron phosphate system, namely an LFP system, the SOC can only take an interval corresponding to an area with obvious voltage slope change, so as to ensure the accuracy of a final evaluation result; and when the battery cell 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 electric cores to be evaluated can be balanced by the voltage balancing device to reach the same value, and recorded as V.
Step S103: and respectively carrying out constant-voltage charging on the electric cores to be evaluated according to the balanced voltage value, and calculating the self-discharge capacity of the electric cores to be evaluated.
Specifically, each battery cell is charged at a constant voltage under a voltage V, after h hours of charging, the relation between the constant-voltage charging current and the charging time of each battery cell is recorded, and the self-discharge capacity corresponding to the battery cell is calculated according to the relation between the constant-voltage charging current and the charging time of the battery cell.
Step S104: and 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 the self-discharge performance evaluation result of each battery cell to be evaluated.
Specifically, a cell self-discharge outlier judgment factor is obtained by analyzing the rated capacity and the self-discharge capacity corresponding to each cell to be evaluated, and then the self-discharge consistency of the cell is accurately evaluated according to the specific numerical value of the cell self-discharge outlier judgment factor.
By executing the above steps, the method for evaluating the self-discharge performance of the battery core provided by the embodiment of the invention calculates the self-discharge capacity of each battery core in a constant voltage charging mode of the battery core in a specified state of charge, namely, an SOC state, and evaluates the self-discharge performance of each battery core by comprehensively considering the rated capacity and the self-discharge capacity of each battery core, so as to provide an accurate data basis for screening and matching of the battery cores, thereby improving the consistency of the battery after matching, ensuring the performance of the battery, and in addition, the self-discharge capacity of the battery core in any temperature, any SOC state and any time can be quickly and accurately obtained, and the calculation efficiency of the self-discharge capacity is improved.
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 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 cell charging is completed, such as: 0.05C, etc. Illustratively, the first current value is 1/3C, which is only used as an example and not limited herein.
Step S202: and discharging the current electric core to be evaluated to the discharge cut-off voltage at a first current value respectively, and recording the constant-current discharge capacity.
Specifically, for the battery cells with the same specification, the discharge cut-off voltages are the same, in the embodiment of the present invention, the discharge cut-off voltages of the N battery cells to be evaluated are the same, and the specific value of the discharge cut-off voltage is related to the model of the battery cell to be evaluated, which is not described herein again.
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 at ambient temperature T at 1/3C constant current to a cutoff voltage, a constant voltage charge to a current of 0.05C; standing for 0.5 hour, performing 1/3C constant current discharge to discharge cut-off voltage, recording constant current discharge capacity, wherein the recorded constant current discharge capacity is the rated capacity Q of the battery celliAnd i represents the number of the battery cell to be identified. Therefore, the actual capacity of each battery cell to be identified can be accurately obtained by calibrating the rated capacitance of the battery cell, and the accuracy of the final self-discharge performance evaluation result of the battery cell is further improved.
Specifically, in an embodiment, the step S103 specifically includes the following steps:
step S301: and carrying out constant voltage charging on the current battery cell to be evaluated according to the balanced voltage value, and recording the real-time charging current.
Step S302: and after the charging time reaches the set constant voltage charging time, calculating the self-discharging capacity of the current to-be-evaluated battery cell based on the relation between the real-time charging current and the charging time.
Illustratively, each cell was subjected to constant voltage charging at the above voltage V at an ambient temperature T, and after charging for h hours, the current of the constant voltage charging of each cell was 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 of the current evolution of each cell during constant voltage charging in constant voltage charging, where jiAnd showing the current change curve of the ith cell to be evaluated. According to the charging current jiThe self-discharge capacity of the ith battery cell can be calculated by integrating the charging time t, namely the self-discharge capacity of the battery cell in the specified SoC, the specified temperature and the specified time.
Therefore, after voltage-sharing processing is carried out on each battery cell, constant-voltage charging is carried out according to the voltage value after voltage sharing, the obtained self-discharge capacity can directly reflect the difference of the self-discharge performance of each battery cell, and the accuracy of the final self-discharge performance evaluation result of the battery cell 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 electric core to be evaluated.
Specifically, the average rated capacity can be calculated by the following formula (1):
wherein the content of the first and second substances,
representing the average rated capacity, N representing the number of cells to be evaluated, i representing the number of cells to be evaluated, QiAnd indicating the rated capacity corresponding to the ith battery cell to be evaluated.
Step S402: and calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each cell to be evaluated.
Specifically, the average self-discharge capacity can be calculated by the following formula (2):
wherein the content of the first and second substances,
represents the average self-discharge capacity, N represents the number of the cells to be evaluated, i represents the number of the cells to be evaluated,
and the self-discharge capacity corresponding to the ith cell to be evaluated is shown.
Step S403: and calculating the rated capacity deviation of the current battery core to be evaluated based on the relation between the rated capacity corresponding to the current battery core to be evaluated and the average rated capacity.
Specifically, the rated capacity deviation can be calculated by the following formula (3):
wherein, deltaiThe rated capacity deviation of each cell to be evaluated is shown,
representing the average rated capacity, QiAnd indicating the rated capacity corresponding to the ith battery cell to be evaluated.
Step S404: and calculating the self-discharge capacity deviation of the current to-be-evaluated battery cell based on the relation between the self-discharge capacity corresponding to the current to-be-evaluated battery cell and the average self-discharge capacity.
Specifically, the self-discharge capacity deviation can be calculated by the following formula (4):
wherein σiRepresents the deviation of the self-discharge capacity of the ith cell to be evaluated,
the average self-discharge capacity is shown,
and the self-discharge capacity corresponding to the ith cell to be evaluated is shown.
Step S405: and determining a self-discharge performance evaluation result corresponding to the current battery core to be evaluated based on the rated capacity deviation and the self-discharge capacity deviation of the current battery core 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 equation (5):
wherein epsiloniA cell self-discharge outlier judgment factor, sigma, representing the consistency evaluation value of each ith cell to be evaluatediRepresents the deviation of the self-discharge capacity, delta, of each cell to be evaluatediAnd (4) representing the rated capacity deviation of each 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 relation between the consistency evaluation value and the preset evaluation threshold range.
Specifically, the step S52 is executed specifically by determining whether the consistency evaluation value is within a preset evaluation threshold range; when the consistency evaluation value is within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery cell to be evaluated meets the requirement of battery consistency of the current battery cell to be evaluated; and when the consistency evaluation value is not within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current electric core to be evaluated is that the current electric core to be evaluated does not meet the requirement of battery consistency.
For example, a distribution diagram of the cell self-discharge outlier determination factors, which are the consistency evaluation values of the N cells, is shown in fig. 3, when ∈ is reachediWhen the discharge rate is more than 1, the self-discharge rate of the battery cell is higher, otherwise, epsiloni<1, the self-discharge rate of the battery cell is lower; if epsiloniWhen the self-discharge rate of each cell is completely consistent, the cell group matching only needs to consider parameters such as capacity, internal resistance and the like, and the self-discharge rate does not need to be considered. In fact, epsilon per celliThe values all float up and down at 1, so that the preset evaluation threshold range can be flexibly set according to the actual battery grouping requirement to screen the battery cells.
Specifically, when 0.99<εi<At 1.01, the cell can be considered to be self-dischargingThe performance is better, and the battery pack can be used for matching battery packs or batteries. In practice, only epsiloniCells with the value within the range of +/-0.01 can be used for matching, but considering that the service life of the cells is influenced by overhigh self-discharge rate, epsilon is generally selected when the cells are matchedi<The interval 1.01 is only used as an example, and the invention is not limited thereto.
Therefore, the battery cores are screened, graded and grouped by calculating the consistency evaluation values of the battery cores to be evaluated, so that the battery or the battery pack with better consistency performance can be obtained, the stability of the battery or the battery pack is further improved, the service life is prolonged, and the use experience of a user is improved.
Specifically, in an embodiment, the method for evaluating self-discharge performance of a battery cell further includes the following steps:
step S105: and rejecting the battery cell to be evaluated which does not meet the requirement of battery consistency.
Specifically, when the batteries are selected to be assembled, the consistency of the self-discharge performance among the batteries is better, and the consistency of the batteries is better, so that when the batteries are assembled, the batteries to be evaluated which do not meet the requirement of the consistency of the batteries are eliminated, and therefore, the battery packs or the batteries which are selected to be assembled in the rest batteries can ensure the consistency of the batteries, the problem of accelerated decline of the battery capacity is avoided, the stability of the batteries or the battery packs is improved, and the user experience is improved.
As shown in fig. 4, the method for evaluating the self-discharge performance of the battery core provided by the embodiment of the invention can quickly and accurately obtain the self-discharge capacity of the battery core at any temperature, in any SOC state and in any time, quickly evaluate the self-discharge rate of the battery core according to the self-discharge outlier judgment factor of each battery core, and screen and group the battery cores by setting a reasonable self-discharge outlier judgment factor, thereby providing an accurate data base for improving the battery performance, prolonging the battery service life and improving the user experience.
By executing the above steps, the method for evaluating the self-discharge performance of the battery core provided by the embodiment of the invention calculates the self-discharge capacity of each battery core in a constant voltage charging mode of the battery core in a specified state of charge, namely, an SOC state, and evaluates the self-discharge performance of each battery core by comprehensively considering the rated capacity and the self-discharge capacity of each battery core, so as to provide an accurate data basis for screening and matching of the battery cores, thereby improving the consistency of the battery after matching, ensuring the performance of the battery, and in addition, the self-discharge capacity of the battery core in any temperature, any SOC state and any time can be quickly and accurately obtained, and the calculation efficiency of the self-discharge capacity is improved.
An embodiment of the present invention further provides an apparatus for evaluating a self-discharge performance of a battery cell, as shown in fig. 5, the apparatus for evaluating a self-discharge performance of a battery cell includes:
the obtaining module 101 is configured to obtain a rated capacity corresponding to each to-be-evaluated electrical core. For details, refer to the related description of step S101 in the above method embodiment, and no further description is provided here.
The first processing module 102 is configured to perform voltage equalization on each to-be-evaluated battery cell after each to-be-evaluated battery cell is adjusted to the same set state of charge, so as 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 provided here.
And the second processing module 103 is configured to perform constant-voltage charging on each to-be-evaluated battery cell by using the balanced voltage value, and calculate a self-discharge capacity of each to-be-evaluated battery cell. For details, refer to the related description of step S103 in the above method embodiment, and no further description is provided here.
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 provided here.
Through the cooperative cooperation of the above components, the self-discharge performance evaluation device for the battery core provided by the embodiment of the invention calculates the self-discharge capacity of each battery core by performing constant-voltage charging on the battery core in a specified charge state, namely an SOC state, and evaluates the self-discharge performance of each battery core by comprehensively considering the rated capacity and the self-discharge capacity of each battery core, so that an accurate data basis is provided for the screening and grouping of the battery cores, the consistency of the battery after grouping is further improved, the battery performance is ensured, in addition, the self-discharge capacity of the battery core in any temperature, any SOC state and any time can be rapidly and accurately obtained, and the calculation efficiency of the self-discharge capacity is improved.
Further functional descriptions of the modules are the same as those of the corresponding method embodiments, and are not repeated herein.
There is also provided an electronic device according to an embodiment of the present invention, as shown in fig. 6, the electronic device may include a processor 901 and a memory 902, where the processor 901 and the memory 902 may be connected by a bus or in another manner, and fig. 6 illustrates an example of a connection by a bus.
The memory 902, which is a non-transitory computer readable storage medium, may be used 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 and data processing of the processor by executing non-transitory software programs, instructions and modules stored in the memory 902, that is, implements the methods in the above-described method embodiments.
The memory 902 may include a storage program area and a storage data area, wherein the storage program area may store an application program required for operating the device, at least one function; the storage data area may store data created by the processor 901, and the like. Further, 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, the memory 902 may optionally include memory located remotely from the processor 901, which may be connected to the 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, which when executed by the processor 901 performs the methods in the above-described method embodiments.
The specific details of the electronic device may be understood by referring to the corresponding related descriptions and effects in the above method embodiments, and are not described herein again.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, and the program can be stored in a computer readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD) or a Solid State Drive (SSD), etc.; the storage medium may also comprise a combination of memories of the kind described above.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (10)
1. A method for evaluating the self-discharge performance of a battery cell is characterized by comprising the following steps:
acquiring the rated capacity corresponding to each battery cell to be evaluated;
after adjusting the electric cores to be evaluated to the same set charge state, carrying out voltage equalization on the electric cores 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 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 the self-discharge performance evaluation result of each battery cell to be evaluated.
2. The method according to claim 1, wherein the obtaining of the rated capacity corresponding to each battery cell to be evaluated comprises:
respectively charging the current battery cell to be evaluated to a charging cut-off voltage by a first current value, 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 at a first current value respectively, 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 step of performing constant-voltage charging on each cell to be evaluated according to the equalization voltage value and calculating the self-discharge capacity of each cell to be evaluated comprises:
carrying out constant voltage charging on the current battery cell to be evaluated according to the balanced voltage value, and recording real-time charging current;
and after the charging time reaches the set constant voltage charging time, calculating the self-discharging 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 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 method comprises:
calculating the average rated capacity based on the rated capacity corresponding to each electric core to be evaluated;
calculating the average self-discharge capacity based on the self-discharge capacity corresponding to each electric core to be evaluated;
calculating the rated capacity deviation of the current battery core to be evaluated based on the relation between the rated capacity corresponding to the current battery core to be evaluated and the average rated capacity;
calculating the self-discharge capacity deviation of the current to-be-evaluated battery cell based on the relation between the self-discharge capacity corresponding to the current to-be-evaluated battery cell 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.
5. The method of claim 4, wherein the determining the 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 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 relation between the consistency evaluation value and a preset evaluation threshold range.
6. The method according to claim 5, wherein the determining the 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 includes:
judging whether the consistency evaluation value is within the preset evaluation threshold range;
when the consistency evaluation value is within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery core to be evaluated meets the requirement of battery consistency of the current battery core to be evaluated;
and when the consistency evaluation value is not within the preset evaluation threshold range, determining that the self-discharge performance evaluation result corresponding to the current battery core to be evaluated does not meet the requirement of battery consistency.
7. The method of claim 6, further comprising:
and rejecting the battery cell to be evaluated which does not meet the requirement of battery consistency.
8. An electric core self-discharge performance evaluation device, comprising:
the acquisition module is used for acquiring the rated capacity corresponding to each electric core to be evaluated;
the first processing module is used for adjusting the electric cores to be evaluated to the same set charge state and then carrying out voltage equalization on the electric cores to be evaluated 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 on the basis of the rated capacity and the self-discharge capacity corresponding to each battery cell to be evaluated to obtain the self-discharge performance evaluation result of each battery cell to be evaluated.
9. 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 performing the method of any of claims 1-7 by executing the computer instructions.
10. A computer-readable storage medium having stored thereon computer instructions for causing a computer to thereby perform the method of any one of claims 1-7.
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