CN109664795B - Battery pack passive equalization method and battery management system - Google Patents
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Abstract
The embodiment of the invention provides a battery pack passive equalization method and a battery management system, which are used for realizing passive equalization of a battery pack. In the passive equalization method, the capacity, the residual discharge capacity and the residual charge capacity of each battery cell in the battery pack are estimated; determining a first reference battery cell x with the minimum capacity from the plurality of battery cells, and determining a second reference battery cell y with the minimum residual discharge capacity; and determining a target balance electric quantity value and a reference residual charge electric quantity of the monomer x according to the residual discharge electric quantity and the residual charge electric quantity of the monomer x and the monomer y, and determining target balance electric quantity values of other monomers according to the reference residual charge electric quantity. And finally, discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity is equal to the corresponding target balance electric quantity value. The equalization method provided by the embodiment of the invention can realize the capacity maximization effect, and the residual discharge capacity of the battery pack can not be influenced in the equalization process.
Description
Technical Field
The invention relates to the field of battery management, in particular to a battery pack passive equalization method and a battery management system.
Background
The vehicle power battery pack is generally formed by connecting hundreds of battery monomers in series and parallel. Due to the limitations of battery manufacturing processes and production equipment, even if the battery cells are in the same batch, inconsistency can still exist in the aspects of capacity, self-discharge rate and the like; meanwhile, the environments (such as temperature) of each battery cell in the battery pack are different, and the capacity and the electric quantity (namely the charge quantity) of the battery cells are different due to the above reasons, and the difference is more and more obvious along with the use of the battery.
In order to ensure the use safety of the battery, when the electric quantity of a certain battery monomer is discharged, the battery pack stops discharging; when the battery is fully charged, the battery pack stops charging. Therefore, the inconsistency of the capacity and the electric quantity among the battery cells directly results in the reduction of the actual available capacity of the battery pack. In order to minimize the inconsistency between the cells, the stack of cells needs to be balanced.
The equalization performed on the battery pack is generally called passive equalization or dissipation equalization, and the passive equalization improves the consistency among the battery cells by discharging part of the battery cells. How to achieve passive equalization is the hot of current research and development.
Disclosure of Invention
In view of this, embodiments of the present invention provide a battery pack passive equalization method and a battery management system, so as to implement passive equalization on a battery pack.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
a method of passive equalization of a battery pack, the battery pack including a plurality of cells connected in series, the method comprising:
estimating the capacity, the residual discharge capacity and the residual charge capacity of each battery cell; the residual discharge electric quantity is the electric quantity of the battery monomer in the current state; the residual charging capacity is the capacity which needs to be supplemented when the battery monomer reaches a full-charge state from the current state;
determining a battery cell with the minimum capacity from the plurality of battery cells; the battery cell with the minimum capacity is a first reference battery cell x;
determining a battery cell with the minimum residual discharge capacity from the plurality of battery cells; the battery monomer with the minimum residual discharge electric quantity is a second reference battery monomer y;
if the first reference battery cell x and the second reference battery cell y are the same battery cell, recording a target equalization electric quantity value of the first reference battery cell x as 0; otherwise, recording the difference value of the residual discharge electric quantity of the first reference battery monomer x and the second reference battery monomer y as the target balance electric quantity value of the first reference battery monomer x; taking the sum of the residual charging capacity of the first reference battery cell x and the target equalization capacity value of the first reference battery cell as a reference residual charging capacity;
for any other battery cell, if the residual charging capacity is not less than the reference residual charging capacity, recording the target equalization capacity value of the any other battery cell as 0; if not, recording the difference value between the reference residual charging capacity and the residual charging capacity of any other battery monomer as the target equalizing capacity value of any other battery monomer;
and discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery monomer is equal to the corresponding target balance electric quantity value.
Optionally, the method further includes: reading the stored electric quantity value when the battery pack is powered on and powered off last time, and calculating the accumulated charge-discharge electric quantity value of the battery pack in real time by taking the read electric quantity value as an initial value; and storing the calculated last accumulated charge-discharge electric quantity value when the power is turned off.
Optionally, any battery cell in the plurality of battery cells is represented by a battery cell i; the capacity of the battery cell i is estimated as follows: acquiring the state of charge (SOC) of the battery monomer i corresponding to a first target moment during power-on1,iAnd accumulated charging and discharging electric quantity value Q1(ii) a Meanwhile, acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iAnd accumulated charging and discharging electric quantity value Q2(ii) a According to the SOC1,i、Q1、SOC2,iAnd Q2Estimating the capacity C of the battery cell ibat,i(ii) a The first target time and the second target time are different power-on and power-on times, and the time difference between the first target time and the last power-off and power-off time is not less than a preset standing time threshold.
Optionally, the capacity Cbat,iCalculated by the following formula:
optionally, the state of charge SOC of the battery cell i at the first target time is obtained1,iThe method comprises the following steps: reading a terminal voltage value corresponding to the first target moment as a first open-circuit voltage value, and determining that the state of charge corresponding to the first open-circuit voltage value is the SOC according to the calibration relation of the state of charge and the open-circuit voltage1,i(ii) a Acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iThe method comprises the following steps: reading a terminal voltage value corresponding to the second target moment as a second open-circuit voltage value, and determining the state of charge corresponding to the second open-circuit voltage value as the SOC according to the calibration relation2,i。
Optionally, the second target time is later than the first target time; the residual discharge capacity of the battery monomer i is the residual discharge at the second target momentElectric quantity QDCH,i(ii) a The remaining discharge capacity Q of the second target timeDCH,iEstimated by the following formula:
optionally, the remaining charge capacity of the battery cell i is the remaining charge capacity Q at the second target timeCHA,i(ii) a The remaining charge capacity at the second target time is estimated by the following formula:
a battery management system for providing equalization control for a battery pack, the battery pack including a plurality of cells connected in series, the system comprising:
an estimation unit for estimating a capacity, a remaining discharge capacity, and a remaining charge capacity of each battery cell;
an equalizing charge value calculating unit for:
determining a battery cell with the minimum capacity from the plurality of battery cells; the battery cell with the minimum capacity is a first reference battery cell;
determining a battery cell with the minimum residual discharge capacity from the plurality of battery cells; the battery cell with the minimum residual discharge electric quantity is a second reference battery cell;
if the first reference battery cell and the second reference battery cell are the same battery cell, recording a target equalization electric quantity value of the first reference battery cell as 0; if not, recording the difference value of the residual discharge electric quantity of the first reference battery cell and the second reference battery cell as the target balance electric quantity value of the first reference battery cell; the sum of the residual charging capacity of the first reference battery cell and the target equalization capacity value of the first reference battery cell is used as a reference residual charging capacity;
for any other battery cell, if the residual charging capacity is not less than the reference residual charging capacity, recording the target equalization capacity value of the any other battery cell as 0; if not, recording the difference value between the reference residual charging capacity and the residual charging capacity of any other battery monomer as the target equalizing capacity value of any other battery monomer;
and the balance control unit is used for discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery monomer is equal to the corresponding target balance electric quantity value.
Optionally, the estimating unit is further configured to: reading the stored electric quantity value when the battery pack is powered on and powered off last time, calculating the accumulated charge-discharge electric quantity value of the battery pack in real time by taking the read electric quantity value as an initial value, and storing the calculated last accumulated charge-discharge electric quantity value when the battery pack is powered off; in terms of estimating the capacity of each of the battery cells, the estimating unit is specifically configured to: during power-on, acquiring the state of charge (SOC) of the battery monomer i corresponding to the first target moment1,iAnd accumulated charging and discharging electric quantity value Q1(ii) a Meanwhile, acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iAnd accumulated charging and discharging electric quantity value Q2(ii) a The battery cell i represents any battery cell in the plurality of battery cells; according to the SOC1,i、Q1、SOC2,iAnd Q2Estimating the capacity C of the battery cell ibat,i(ii) a The first target time and the second target time are different power-on and power-on times, and the time difference between the first target time and the last power-off and power-off time is not less than a preset standing time threshold.
Optionally, the state of charge SOC of the battery cell i at the first target time is obtained1,iThe estimating unit is specifically configured to: reading a terminal voltage value corresponding to the first target moment as a first open-circuit voltage value, and determining that the state of charge corresponding to the first open-circuit voltage value is the SOC according to the calibration relation of the state of charge and the open-circuit voltage1,i(ii) a At the second target moment of acquiring the battery monomer iCorresponding state of charge SOC2,iThe estimating unit is specifically configured to: reading a terminal voltage value corresponding to the second target moment as a second open-circuit voltage value, and determining the state of charge corresponding to the second open-circuit voltage value as the SOC according to the calibration relation2,i。
The final purpose of battery pack equalization is to maximize the capacity of the battery pack, and since the battery cells in the battery pack are connected in series, the capacity maximization effect achieved by passive equalization is as follows: the battery pack capacity is equal to the minimum value of the capacities of the individual batteries.
In the embodiment of the present invention, the first reference cell is the cell with the smallest capacity, and the capacity of the battery pack should be equal to the capacity of the first reference cell to maximize the capacity. Or, it should be avoided that the other battery cells reach the full charge state before the first reference battery cell, and at the same time, it is also avoided that the other battery cells reach the electric quantity emptying state before the first reference battery cell, so that the capacity maximization effect can be realized.
After the discharging process is completed, the remaining charging capacity of the first reference battery cell is equal to the reference remaining charging capacity, and the remaining charging capacities of the other battery cells are not less than the reference remaining charging capacity. In this way, the other battery cells reach the full charge state at most simultaneously with the first reference battery cell, without reaching the full charge state prior to the first reference battery cell, at the time of charging.
The remaining discharge capacity of the battery pack is the remaining discharge capacity (denoted as Q) of the cell with the smallest remaining discharge capacity (i.e., the second reference cell y)DCH,y) To be determined. Let the capacity of the first reference cell be CxAnd the capacity of the second reference cell is denoted as CyAfter the first reference cell x is discharged or not, the remaining discharge capacity of the first reference cell x is QDCH,yThe remaining charge capacity (i.e., reference remaining charge capacity) is denoted as Q'CHA,xAnd Q'CHA,x＝(Cx-QDCH,y) As for the second reference cell y, the remaining charge capacity before the discharge process is (C)y-QDCH,y) Due to Cy≥CxThen (C)y-QDCH,y)≥(Cx-QDCH,y) That is, no discharge process is performed on the second reference cell regardless of whether the first reference cell and the second reference cell are the same cell, so that the remaining discharge capacity of the second reference cell is maintained at QDCH,y。
Recording the residual discharge capacity of any battery cell z except the first reference battery cell and the second reference battery cell as QDCH,zConsider the following two cases:
in the first case, the remaining charge capacity of the battery cell z is not less than the reference remaining charge capacity, and the discharge process will not be performed, so that the battery cell z will maintain the original remaining discharge capacity QDCH,zQ is determined by the minimum remaining discharge capacity of the second reference cellDCH,z≥QDCH,y；
In the second case, when the remaining charge capacity of the battery cell z is smaller than the reference remaining charge capacity, the discharge process is performed assuming that the capacity of the battery cell z is CzAfter the discharging is completed, the remaining charge capacity of the battery cell z will be equal to the reference remaining charge capacity QCHA,xAnd then the residual discharge capacity Q 'of the battery cell z'DCH,z＝Cz-Q′CHA,xDue to Cz≥CxThen (C)z-Q′CHA,x)≥(Cx-Q′CHA,x) And C isx-Q′CHA,xAnd equal to the residual discharge capacity Q of the second reference cellDCH,yTherefore, after the discharge process is completed, the remaining discharge capacity of the battery cell z will be equal to QDCH,y。
Accordingly, it can be seen that the remaining discharge capacity of the battery cell z is not less than the remaining discharge capacity Q of the second reference battery cell regardless of whether the discharge process is performed or notDCH,y. That is, after the passive equalization, the remaining discharge capacity of the battery pack is equal to the remaining discharge capacity of the second reference cell, so that the remaining discharge capacity of the battery pack is not affected.
That is, after equalization is completedThe remaining discharge capacity of the first reference cell x is QDCH,yThe residual discharge capacity of other battery cells is not less than QDCH,yAnd thus the charge-discharged state is not reached prior to the first reference cell x.
Therefore, after the battery pack is passively equalized by the passive equalization method provided by the invention, the residual discharge electric quantity of other battery monomers is not less than the residual discharge electric quantity of the first reference battery monomer x, so that the battery pack does not reach an electric quantity emptying state before the first reference battery monomer x. During charging, the other cells reach the full charge state at most simultaneously with the first reference cell x, and do not reach the full charge state prior to the first reference cell x. The first reference cell x is the cell having the smallest capacity, and thus the capacity maximizing effect can be achieved.
In summary, the passive equalization method and the battery management system for the battery pack provided by the embodiment of the invention can realize the capacity maximization effect, and the residual discharge capacity of the battery pack is not influenced in the equalization process.
Drawings
Fig. 1 is an exemplary flowchart of a battery pack passive equalization method according to an embodiment of the present invention;
fig. 2a is a schematic diagram illustrating a state of a battery cell in the battery pack according to the embodiment of the invention;
fig. 2b is a schematic diagram illustrating states of single batteries in the battery pack after equalization according to the embodiment of the present invention;
fig. 2c is a schematic diagram of the states of the battery cells before and after equalization and after full charge according to the embodiment of the present invention;
fig. 3 is another exemplary flowchart of a passive equalization method for a battery pack according to an embodiment of the present invention;
fig. 4 is a flowchart illustrating a passive equalization method for a battery pack according to an embodiment of the present invention;
fig. 5 is a schematic diagram of equalization of an existing equalization strategy based on remaining charge capacity equalization;
fig. 6 is a schematic diagram of equalization of an existing equalization strategy based on remaining discharge power consistency;
fig. 7 is an exemplary block diagram of a battery management system according to an embodiment of the present invention.
Detailed Description
The invention provides a Battery pack passive equalization method and a Battery Management System (BMS) to realize passive equalization of a Battery pack.
The equalized battery pack includes a plurality of battery cells connected in series.
The battery pack passive equalization method and the BMS provided by the embodiment of the invention can realize the effect of maximizing the capacity of the battery pack, and the residual discharge capacity of the battery pack is not influenced in the equalization process, so the battery pack passive equalization method provided by the embodiment of the invention can be executed in the driving process.
Fig. 1 shows an exemplary flow of a battery pack passive equalization method performed by a BMS, including:
s0: the BMS is powered up.
S1: the capacity, the remaining discharge capacity, and the remaining charge capacity of each battery cell are estimated.
The residual discharge electric quantity is the electric quantity of the single battery in the current state, and the residual charge electric quantity is the electric quantity which needs to be supplemented when the single battery reaches the full-charge state from the current state. That is, the sum of the remaining discharge capacity and the remaining charge capacity is equal to the capacity of the battery cell.
There are different ways of estimating the above capacity, one of which will be described later herein.
S2: the battery cell with the smallest capacity (first reference battery cell x, referred to as cell x for short) is determined from the plurality of battery cells.
The remaining discharge capacity of the first reference cell x can be recorded as QDCH,xThe remaining charge capacity can be recorded as QCHA,xWhere the subscript DCH denotes discharge and CHA denotes charge.
Taking four battery cells as an example, please refer to fig. 2a, the capacity of the battery cell No. 4 is the smallest, which is the first reference battery cell x, the cell with the smallest residual discharge electric quantity is the cell No. 1, the cell with the smallest residual charge electric quantity is the cell No. 3, and the current capacity of the battery pack isEqual to the sum of the residual discharge capacity of the No. 1 monomer and the residual charge capacity of the No. 3 monomer, can be CpackAnd (4) showing.
S3: determining a target equalization charge value Q for a first reference cell xEQ,x。
Wherein the target equalizing electric quantity value QEQ,xRefers to the amount of power to dissipate the discharge.
In one example, a battery cell (second reference battery cell y, referred to as cell y for short) with the smallest residual discharge capacity can be determined from the plurality of battery cells, and the residual discharge capacity (Q) of the cell y is determined according to the cell yDCH,y) Determination of QEQ,x. Still taking the four cells in fig. 2a as an example, the remaining discharge capacity of the cell No. 1 is the smallest, and is the second reference cell y.
Specifically, if the monomer x and the monomer y are the same battery monomer, that is, the monomer x is just the monomer with the minimum residual discharge capacity, the monomer x does not need to be balanced, and the Q of the monomer x isEQ,xAnd is noted as 0.
Otherwise, the difference between the residual discharge capacities of the monomer x and the monomer y is recorded as the target equilibrium capacity value of the monomer x, i.e. QEQ,x＝QDCH,x-QDCH,y。
After monomer x is balanced, the residual discharge capacity is as follows: qD'CH,x＝QDCH,x-QEQ,xThe remaining charging capacity is: qC'HA,x＝QCHA,x+QEQ,xAs shown by monomer No. 4 in fig. 2 b. After the equalization, the residual discharge capacity of the cell x is equal to the residual discharge capacity of the cell y.
The residual charge capacity of the cell x after equalization may also be referred to as a reference residual charge capacity, and when determining the target equalization capacity value of other battery cells, the reference residual charge capacity is used.
S4: and determining target balance electric quantity values of other battery monomers according to the reference residual charging electric quantity.
Any other battery cell except the cell x may be referred to as a cell j, and for the cell j except the cell x, if the remaining charge capacity is not less than the reference remaining charge capacity (for example, No. 1 and No. 2 cells in fig. 2 a), the target equalizing capacity value of the cell j may be marked as 0.
That is, if QCHA,j>＝QCHA,x+Q,EQ,xThen monomer j does not need to be equalized and its target equalizing electric quantity value QEQ,j＝0。
This is because, if the remaining charge capacity of the cell j is not less than the reference remaining charge capacity (for example, cell No. 1 in fig. 2 a), the remaining discharge capacity of the cell j is not emptied before the remaining discharge capacity of the cell x is emptied; before the monomer x is fully charged, the monomer j cannot be fully charged in advance, so that the monomer j has no influence on the capacity of the battery pack and does not need to be balanced.
And if the residual charge capacity of the monomer j is smaller than the reference residual charge capacity, the monomer j needs to be balanced. At this time, the difference between the reference remaining charge capacity and the remaining charge capacity of the cell j is recorded as the target equalizing capacity value of the cell j.
That is, if QCHA,j<QCHA,x+Q,EQ,xThen monomer j needs to be equalized with its target equalizing charge value QEQ,j＝QCHA,x+Q,EQ,x-QCHA,j。
This is because, taking the cell No. 3 in fig. 2a as an example, it can be seen that when the remaining discharge capacity of the cell is exhausted, the battery pack stops discharging, and at this time, the cell No. 3 still has a part of remaining discharge capacity not being exhausted; before the monomer x is fully charged, the monomer 3 reaches the full charge state, and the battery pack stops charging, thereby affecting the capacity of the battery pack. Therefore, it is necessary to balance the cell No. 3 and discharge part of the electric power, so that the cell No. 3 and the cell x (cell No. 4) have the same remaining charge capacity after the balance is completed (see fig. 2b), and can be fully charged at the same time, thereby achieving the effect of increasing the capacity of the battery pack.
S5: and discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery monomer is equal to the corresponding target balance electric quantity value.
Each of the target equalizing electric quantity values determined in steps S4 and S5 may be regarded as an initial target equalizing electric quantity value, and it can be understood that the electric quantity to be discharged is less and less as the discharging time is prolonged. Therefore, the target equalization electric quantity value of each battery cell can be updated in real time in the discharging process, and the discharging process is stopped until the target equalization electric quantity values of all the battery cells are all 0, namely, one-time passive equalization is completed.
Specifically, the BMS may calculate the amount of power that has been discharged through equalization according to the actual magnitude of the equalization current, and then update the target equalization power value.
After the passive equalization is completed, the remaining charge capacity of each battery cell is equal to or greater than the reference remaining charge capacity.
After equalization, referring to fig. 2b or fig. 2c, the battery capacity is equal to the capacity of cell No. 4, which can be represented by Cpack'.
It has been mentioned above that the capacity maximization effect achieved by passive equalization is: the battery pack capacity is equal to the minimum value of the capacities of the individual batteries.
In the embodiment of the present invention, the first reference cell x is the cell with the smallest capacity, and therefore, the capacity of the battery pack should be equal to the capacity of the first reference cell x to maximize the capacity. Or, it should be avoided that the other battery cells reach the full state before the first reference battery cell x, and at the same time, it is also avoided that the other battery cells reach the electric quantity emptying state before the first reference battery cell x, so that the capacity maximization effect can be achieved. Still taking the four battery cells in fig. 2a as an example, the states of the four battery cells after equalization and after full charge are shown in fig. 2c, it can be seen that the capacity of the battery pack reaches the minimum value of the capacities of the battery cells, and the maximization effect is achieved.
According to the method provided by the embodiment of the invention, after the discharging process is completed, the residual charging capacity of the first reference battery cell x is equal to the reference residual charging capacity, and the residual charging capacities of other battery cells are not less than the reference residual charging capacity. In this way, the other battery cells reach the full charge state at most simultaneously with the first reference battery cell, without reaching the full charge state prior to the first reference battery cell, at the time of charging.
In addition, the remainder of the battery packThe remaining discharge capacity is the remaining discharge capacity (denoted as Q) of the cell (i.e., the second reference cell y) having the smallest remaining discharge capacityDCH,y) To be determined. Let the capacity of the first reference cell be CxAnd the capacity of the second reference cell is denoted as CyAfter the passive equalization is completed, the remaining discharge capacity of the first reference battery cell x is QDCH,yThe remaining charge capacity (i.e., reference remaining charge capacity) is denoted as Q'CHA,xAnd Q'CHA,x＝(Cx-QDCH,y) As for the second reference cell y, the remaining charge capacity before the discharge process is (C)y-QDCH,y) Due to Cy≥CxThen (C)y-QDCH,y)≥(Cx-QDCH,y) That is, no matter whether the first reference cell and the second parameter cell are the same cell, the second reference cell is not subjected to discharge processing, that is, the remaining discharge capacity of the second reference cell will maintain QDCH,y。
Recording the residual discharge capacity of any battery cell z except the first reference battery cell and the second reference battery cell as QDCH,zConsider the following two cases:
in the first case, the remaining charge capacity of the battery cell z is not less than the reference remaining charge capacity, and the discharge process will not be performed, so that the battery cell z will maintain the original remaining discharge capacity QDCH,zQ is determined by the minimum remaining discharge capacity of the second reference cellDCH,z≥QDCH,y；
In the case two, when the remaining charge capacity of the battery cell z is smaller than the reference remaining charge capacity, the discharge process is performed assuming that the capacity of the battery cell z is CzAfter the discharging is completed, the residual charging capacity of the battery cell z is equal to the reference residual charging capacity Q'CHA,xAfter the discharge is completed, the remaining discharge capacity Q 'of the battery cell z'DCH,z＝Cz-Q′CHA,xDue to Cz≥CxThen (C)z-Q′CHA,x)≥(Cx-Q′CHA,x) And C isx-Q′CHA,xAnd equal to the residual discharge capacity Q of the second reference cellDCH,yTherefore, after the discharge process is completed, the residual discharge capacity of the battery cell z is equal to or greater than QDCH,y。
Accordingly, it can be seen that the remaining discharge capacity of the battery cell z is not less than the remaining discharge capacity Q of the second reference battery cell regardless of whether the discharge process is performed or notDCH,y. That is, after the passive equalization, the remaining discharge capacity of the battery pack is still equal to the remaining discharge capacity of the second reference cell y, so that the remaining discharge capacity of the battery pack is not affected.
That is, after the equalization is completed, the remaining discharge capacity of the first reference cell x is QDCH,yThe residual discharge capacity of other battery cells is not less than QDCH,yAnd thus the charge-discharged state is not reached prior to the first reference cell x.
Therefore, after the battery pack is passively equalized by the passive equalization method provided by the invention, the residual discharge electric quantity of other battery monomers is not less than the residual discharge electric quantity of the first reference battery monomer x, so that the battery pack does not reach an electric quantity emptying state before the first reference battery monomer x. During charging, the other cells reach the full charge state at most simultaneously with the first reference cell x, and do not reach the full charge state prior to the first reference cell x. And the first reference battery cell x is the battery cell with the minimum capacity, so that the effect of capacity maximization can be realized, and the residual discharge capacity of the battery pack cannot be influenced by the equalization process.
In other embodiments of the present invention, referring to fig. 3, the BMS executes the following steps after being powered on:
and S7, calculating the accumulated charge and discharge electric quantity of the battery pack on line.
Specifically, the BMS reads the charge value stored at the last power-off shutdown when the BMS is powered on and started up, and calculates the accumulated charge-discharge charge value of the battery pack in real time with the read charge value as an initial value.
The BMS may measure a current value passing through the battery pack in real time through the current sensor, and calculate an accumulated charge/discharge capacity value of the battery pack in real time based on the measured current value and the initial value.
More specifically, the following formula can be used for calculation:
wherein, I is current which changes along with time, is positive during charging and negative during discharging, and the monomer is A; t is time in units of s; q represents the accumulated charge-discharge electricity quantity, and the unit is Ah. Since t is in seconds and Q is in amp hours, this is divided by 3600 seconds.
It should be noted that S7 and S1-S6 are executed in parallel. And S7 is continuously executed as long as power-off is not performed.
S8: and storing the calculated last accumulated charge-discharge electric quantity value when the power is turned off.
The accumulated charge-discharge electric quantity value stored when the battery pack is powered off is used as an initial value to calculate the accumulated charge-discharge electric quantity of the battery pack when the battery pack is powered on next time.
The accumulated charge capacity value described above in conjunction with SOC may be used to estimate the capacity of the cell.
Where SOC is the state of charge or state of charge, which is defined as the percentage of the remaining discharge capacity of the battery cell to the capacity.
There are various methods for estimating the SOC, and for example, the estimation can be approximated by a terminal voltage value that is left for a long time. Thus, upon power up, the BMS may also obtain terminal voltage values.
Hereinafter, a detailed description will be given mainly on how to estimate the capacity, the remaining discharge capacity, and the remaining charge capacity of the battery cell. Please refer to fig. 4, which may include the following steps:
s400: the battery cell SOC-OCV relationship is plotted under the line.
Specifically, the Open Circuit Voltage test may be performed in an online manner, and the Open Circuit Voltage value (OCV) of the battery cell is measured at regular SOC intervals (typically 5% or 10%), and an SOC-OCV calibration table or curve is formed to represent the SOC-OCV relationship.
It should be noted that the SOC-OCV curves of the cells in the same batch can be considered to be consistent, and therefore only one cell can be calibrated.
S401: the BMS is powered up.
S402: and the BMS calculates the accumulated charging and discharging electric quantity of the battery pack on line.
S402 is the same as S7 described above, and will not be described herein.
S403: the BMS acquires the SOC values of all the monomers at the first target time t1 and the accumulated charge-discharge electric quantity value Q of the battery pack1。
Any battery cell can be expressed as a battery cell i (called simply a cell i), and the SOC value of the cell i at the first target time t1 is represented as the SOC1,iAnd (4) showing.
It should be noted that t1 is a certain power-on and power-off time, and the time difference between t1 and the last power-off and power-off time is not less than a preset standing time threshold (e.g., 1 hour).
The foregoing mentions that the SOC value can be approximated by the terminal voltage. Specifically, the BMS may obtain a terminal voltage value corresponding to the cell i at a first target time t1 as a first open circuit voltage value, and determine the SOC corresponding to the first open circuit voltage value according to a calibration relationship of the SOC-OCV1,i。
More specifically, taking SOC-OCV calibration table as an example, the SOC can be obtained by interpolating the table according to the SOC-OCV calibration table1,i。
The following describes why the time difference between t1 and the last power-off is not less than the preset standing time threshold.
The SOC-OCV represents a correspondence relationship between SOC and open circuit voltage. However, BMS can measure only terminal voltage values, open circuit voltage is not measurable; only after the battery is sufficiently stood, the terminal voltage can be approximately equal to the open-circuit voltage, so that the terminal voltage value measured at any electrifying moment can not be used for estimating the SOC, and the terminal voltage value at the moment when the standing time meets the standing time threshold value is found to estimate the SOC.
As for the accumulated charge-discharge electric quantity value Q1Since the last accumulated charge and discharge capacity value is recorded when the BMS is powered off, the last accumulated charge and discharge capacity value can be directly readAnd (4) obtaining the compound.
Of course, besides obtaining the SOC value by using the terminal voltage, those skilled in the art may also obtain the SOC value by other manners, which are not described herein.
S404: the BMS acquires the SOC values of all the monomers at the second target time t2 and the accumulated charge-discharge electric quantity value Q of the battery pack2。
t2 is a certain power-on and power-off time, and the time difference between t2 and the last power-off and power-off time is not less than a preset standing time threshold (e.g., 1 hour). Of course, the first target time t1 and the second target time t2 are different power-on times.
SOC value of monomer i at t2 as SOC2,iAnd (4) showing. Specifically, the BMS may obtain a terminal voltage value corresponding to the cell i at a second target time t2 as a second open circuit voltage value, and determine the SOC corresponding to the second open circuit voltage value according to the calibration relationship of the SOC-OCV1,i。
How to obtain SOC2,iAnd obtaining SOC1,iSimilarly, the description is omitted here.
S405: according to the SOC value, Q1And Q2The capacity of each battery cell is estimated, and the remaining discharge capacity and the remaining charge capacity of each battery cell are estimated.
For monomer i, it can be based on SOC1,i、Q1、SOC2,iAnd Q2Estimate its capacity Cbat,i。
In one example, Cbat,iCalculated by the following formula:
as for the remaining discharge capacity, in the case that the second target time is later than the first target time, it may be specifically the remaining discharge capacity Q of the cell i at the second target timeDCH,i(ii) a Similarly, the remaining charge capacity may be specifically the remaining charge capacity Q of the single unit i at the second target timeCHA,i。
Remaining discharge capacity Q at second target timeDCH,iCan be estimated by the following formula:
and the remaining charge capacity Q at the second target timeCHA,iCan be estimated by the following formula:
of course, if the first target time is later than the second target time, the remaining discharge capacity may be the remaining discharge capacity of the single cell i at the first target time, and the remaining charge capacity may be the remaining charge capacity of the single cell i at the first target time.
S406-S409 are the same as S2-S5, and are not described herein.
In the present embodiment, the estimation of the capacity, the remaining discharge capacity, and the remaining charge capacity is simple, and the calculation amount is small. Meanwhile, the SOC-OCV calibration table is basic information which is generally stored in general BMS software, and does not need to occupy extra storage space.
In addition, it should be noted that the above method is performed when the BMS is powered on. If in balanced process, BMS power down, when electrifying again, can divide two kinds of situations:
in the first case, the condition for recalculating the target equalization electric quantity is provided (that is, the standing time is sufficient, and the remaining charge/discharge electric quantity and capacity can be estimated again), and in this case, the passive equalization method may be performed again, and the equalization control may be performed based on the newly calculated target equalization electric quantity.
In the second case, there is no condition for recalculation (for example, the standing time is insufficient), and in this case, the equalization control can be continued using the target equalization electric quantity value stored before the last power-off.
It should be noted that the current equalization strategy is mostly based on a voltage consistency principle or an SOC (state of charge or state of charge, i.e. percentage of remaining discharge capacity to capacity) consistency principle, that is: discharging the battery single cells with higher voltage or higher SOC to keep the voltage or SOC value of all the single cells consistent.
However, due to the inconsistency of the capacities and internal resistances of the different battery cells, the voltage and the SOC cannot directly reflect the residual discharge capacity of the battery cells. For example: a certain single battery with less actual remaining discharge capacity may show a higher voltage or SOC at a certain moment in the discharge process due to a smaller internal resistance or a smaller capacity, and at this time, if equalization is performed based on a consistent voltage or a consistent SOC, the remaining discharge capacity of the single battery may be erroneously equalized, thereby causing a loss of available capacity of the battery pack.
The battery pack passive equalization method and the BMS provided by the embodiment of the invention can realize the effect of maximizing the capacity of the battery pack, and the residual discharge capacity of the battery pack is not influenced in the equalization process.
In addition, in order to achieve an optimal passive equalization effect that the capacity of the battery pack is equal to the minimum value of the capacities of the individual cells, an equalization strategy based on the consistency of the remaining charging capacity is adopted in the existing method.
Referring to fig. 5, when the strategy 1 is adopted, the remaining charge capacity of all the cells is estimated, and then the remaining charge capacities of all the cells are equalized by discharging a part of the cells. Therefore, after equalization is completed, when the battery pack is charged, the electric quantity of all the single batteries can be fully charged at the same time, and the equalization target that the capacity of the battery pack is equal to the minimum value of the capacity of the single batteries is achieved.
However, compared with the passive equalization provided by the embodiment of the present invention, the equalization strategy based on the remaining charge capacity equalization can achieve the capacity maximization as well, but the power dissipated by equalization is usually not the minimum. The more the balance electric quantity is, the more the heat generated in the balance process is, which is not beneficial to the use safety of the balance daughter board and the battery system.
This is because:
assuming that the battery pack includes N battery cells, the maximum value w of the remaining charge capacity in the battery cells before equalization.
For any single battery i, balancing strategy (strategy for short) based on consistency of residual charging capacity1) When the charge of the battery cell i is equalized to the remaining charge Q, the equalized charge is wCHA,iThe difference of (a).
In the present application, the amount of power to be dissipated by each cell is the reference remaining charge u and QCHA,iThe difference of (a).
Then what is the relationship between u and w?
In the present application, after equalization, the remaining discharge capacity of the cell x having the smallest capacity is equal to the remaining discharge capacity of the second reference cell y.
Since the capacity of the cell x is the minimum, when the remaining discharge capacity of the cell x is equal to the remaining discharge capacity of the second reference battery cell y, the remaining charge capacity (i.e., the reference charge capacity) of the cell x after equalization is equal to or less than the remaining charge capacity of the second reference battery cell y.
From this, it can be inferred that the reference charge capacity is equal to or less than the maximum remaining charge amount w of the battery cells before equalization. That is, w is greater than or equal to u, it can be further deduced that the electric quantity equalized by any monomer i by using the strategy 1 is greater than or equal to the electric quantity equalized by using the method of the present application, and thus the dissipation electric quantity of the present application in the equalization process can be obtained to be smaller.
In addition, referring to fig. 6, a balancing strategy (abbreviated as strategy 2) based on remaining discharge capacity consistency is also adopted in the conventional method.
In contrast, the amount of power dissipated by the equalization of the present application is smaller for the following reasons:
Suppose that the residual discharge capacity before any battery cell i is equalized is QDCH,iThen, after the strategy 2 is adopted for equalization, the equalized electric quantity of the battery monomer i is QDCH,i-QDCH,y。
In the present application, the remaining discharge capacity Q of the battery cell i after equalizationDCH,i' is the residual discharge capacity Q of the second reference cell or moreDCH,yAlso, it isThat is, the amount of electricity balanced off by the battery cell i is QDCH,i-QDCH,i’≤QDCH,i-QDCH,y。
The electric quantity equalized by any monomer i by the strategy 2 is more than or equal to the electric quantity equalized by the method, so that the dissipation electric quantity of the method in the equalization process is smaller.
In summary, the passive equalization method provided by the invention calculates the electric quantity to be equalized of each cell on the basis of estimating the remaining charge/discharge electric quantity and capacity of each cell, and performs equalization control based on the electric quantity value to be equalized. The advantages of this approach are:
1) the passive equalization capacity maximizing effect that the capacity of the battery pack is equal to the minimum value of the single capacity can be realized.
2) The equalization process does not affect the current remaining discharge capacity of the battery pack.
3) Each monomer has small balanced electric quantity and small heat productivity in the balancing process.
4) The method is simple and the calculated amount is small. Meanwhile, the SOC-OCV calibration table is basic information which is generally stored in general BMS software, and does not need to occupy extra storage space;
5) the electric quantity of the battery can be updated in real time during each power-on, and the calculation process does not need to acquire the capacity of each battery in advance.
Fig. 7 shows an exemplary structure of the above-described BMS, which may include:
an estimation unit 1 for estimating a capacity, a remaining discharge capacity, and a remaining charge capacity of each battery cell;
an equalizing electric quantity value calculating unit 2 for:
determining a battery monomer with the minimum capacity; the battery cell with the minimum capacity is a first reference battery cell;
determining a battery cell with the minimum capacity from the plurality of battery cells; the battery cell with the minimum capacity is a first reference battery cell;
determining a battery cell with the minimum residual discharge capacity from the plurality of battery cells; the battery cell with the minimum residual discharge electric quantity is a second reference battery cell;
if the first reference battery cell and the second reference battery cell are the same battery cell, recording a target equalization electric quantity value of the first reference battery cell as 0; otherwise, recording the difference value of the residual discharge electric quantity of the first reference battery cell and the second reference battery cell as the target balance electric quantity value of the first reference battery cell; taking the sum of the residual charging capacity of the first reference battery cell x and the target equalization capacity value of the first reference battery cell as a reference residual charging capacity;
for any other battery monomer, if the residual charging capacity is not less than the reference residual charging capacity, recording the target equalization capacity value of any other battery monomer as 0; otherwise, recording the difference value between the reference residual charging capacity and the residual charging capacity of any battery monomer as the target equalizing capacity value of any other battery monomer;
and the balance control unit 3 is used for performing discharge processing on the battery cells with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery cell is equal to the corresponding target balance electric quantity value.
For details, please refer to the above description, which is not repeated herein.
In other embodiments of the present invention, the estimation unit 1 in all the above embodiments is further configured to: and reading the stored electric quantity value when the battery pack is powered on and powered off last time, calculating the accumulated charging and discharging electric quantity value of the battery pack in real time by taking the read electric quantity value as an initial value, and storing the calculated last accumulated charging and discharging electric quantity value when the battery pack is powered off.
In terms of estimating the capacity of each battery cell, the estimating unit 1 may be specifically configured to:
during power-on, acquiring the state of charge (SOC) of the battery monomer i corresponding to the first target moment1,iAnd accumulated charging and discharging electric quantity value Q1(ii) a Meanwhile, acquiring the SOC of the battery monomer i corresponding to the second target moment2,iAnd accumulated charging and discharging electric quantity value Q2(ii) a The battery cell i represents any battery cell;
according to SOC1,i、Q1、SOC2,iAnd Q2Estimate ofCapacity C of cell ibat,i；
The first target time and the second target time are different power-on startup times, and the time difference between the first target time and the last power-off shutdown time is not less than a preset standing time threshold value.
How to depend on SOC1,i、Q1、SOC2,iAnd Q2Estimating the capacity C of the cell ibat,iPlease refer to the above description, which is not repeated herein.
In other embodiments of the present invention, the state of charge SOC of the battery cell i corresponding to the first target time is obtained1,iThe estimation unit 1 may be specifically configured to:
reading a terminal voltage value corresponding to the first target moment as a first open-circuit voltage value, and determining the state of charge corresponding to the first open-circuit voltage value as SOC according to the calibration relation of the state of charge and the open-circuit voltage1,i；
Obtaining the corresponding state of charge SOC of the battery monomer i at the second target moment2,iThe estimating unit is specifically configured to:
reading the terminal voltage value corresponding to the second target moment as a second open-circuit voltage value, and determining the state of charge corresponding to the second open-circuit voltage value as SOC according to the calibration relation2,i。
For a related introduction, reference is made to the description of the foregoing method embodiments, which are not repeated herein.
Those of skill would further appreciate that the various illustrative components and model steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or model described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, WD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for passive equalization of a battery pack comprising a plurality of cells connected in series, the method comprising:
estimating the capacity, the residual discharge capacity and the residual charge capacity of each battery cell; the residual discharge electric quantity is the electric quantity of the battery monomer in the current state; the residual charging capacity is the capacity which needs to be supplemented when the battery monomer reaches a full-charge state from the current state;
determining a battery cell with the minimum capacity from the plurality of battery cells; the battery cell with the minimum capacity is a first reference battery cell x;
determining a battery cell with the minimum residual discharge capacity from the plurality of battery cells; the battery monomer with the minimum residual discharge electric quantity is a second reference battery monomer y;
if the first reference battery cell x and the second reference battery cell y are the same battery cell, recording a target equalization electric quantity value of the first reference battery cell x as 0; otherwise, recording the difference value of the residual discharge electric quantity of the first reference battery monomer x and the second reference battery monomer y as the target balance electric quantity value of the first reference battery monomer x; taking the sum of the residual charging capacity of the first reference battery cell x and the target equalization capacity value of the first reference battery cell x as a reference residual charging capacity;
for any other battery cell except the first reference battery cell x, if the remaining charge capacity is not less than the reference remaining charge capacity, recording a target equalization capacity value of the any other battery cell as 0; if not, recording the difference value between the reference residual charging capacity and the residual charging capacity of any other battery monomer as the target equalizing capacity value of any other battery monomer;
and discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery monomer is equal to the corresponding target balance electric quantity value.
2. The method of claim 1, further comprising:
reading the stored electric quantity value when the battery pack is powered on and powered off last time, and calculating the accumulated charge-discharge electric quantity value of the battery pack in real time by taking the read electric quantity value as an initial value; and storing the calculated last accumulated charge-discharge electric quantity value when the power is turned off.
3. The method of claim 2,
any one of the plurality of battery cells is represented by a battery cell i;
the capacity of the battery cell i is estimated as follows:
acquiring the state of charge (SOC) of the battery monomer i corresponding to a first target moment during power-on1,iAnd accumulated charging and discharging electric quantity value Q1(ii) a Meanwhile, acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iAnd accumulated charging and discharging electric quantity value Q2；
According to the SOC1,i、Q1、SOC2,iAnd Q2Estimating the capacity C of the battery cell ibat,i；
The first target time and the second target time are different power-on and power-on times, and the time difference between the first target time and the last power-off and power-off time is not less than a preset standing time threshold.
4. The method of claim 3, wherein the capacity C isbat,iCalculated by the following formula:
5. the method according to claim 3, wherein the obtaining of the state of charge SOC of the battery cell i at the first target time is performed1,iThe method comprises the following steps:
reading a terminal voltage value corresponding to the first target moment as a first open-circuit voltage value, and determining that the state of charge corresponding to the first open-circuit voltage value is the SOC according to the calibration relation of the state of charge and the open-circuit voltage1,i；
Acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iThe method comprises the following steps:
reading a terminal voltage value corresponding to the second target moment as a second open-circuit voltage value, and determining the state of charge corresponding to the second open-circuit voltage value as the SOC according to the calibration relation2,i。
6. The method of claim 3,
the second target time is later than the first target time;
the residual discharge capacity of the battery monomer i is the residual discharge capacity Q at the second target momentDCH,i；
The remaining discharge capacity Q of the second target timeDCH,iEstimated by the following formula:
7. the method of claim 6,
the residual charging capacity of the battery monomer i is the residual charging capacity Q at the second target momentCHA,i；
The remaining charge capacity at the second target time is estimated by the following formula:
8. a battery management system for performing equalization control of a battery pack including a plurality of battery cells connected in series, the system comprising:
an estimation unit for estimating a capacity, a remaining discharge capacity, and a remaining charge capacity of each battery cell;
an equalizing charge value calculating unit for:
determining a battery cell with the minimum capacity from the plurality of battery cells; the battery cell with the minimum capacity is a first reference battery cell;
determining a battery cell with the minimum residual discharge capacity from the plurality of battery cells; the battery cell with the minimum residual discharge electric quantity is a second reference battery cell;
if the first reference battery cell and the second reference battery cell are the same battery cell, recording a target equalization electric quantity value of the first reference battery cell as 0; if not, recording the difference value of the residual discharge electric quantity of the first reference battery cell and the second reference battery cell as the target balance electric quantity value of the first reference battery cell; the sum of the residual charging capacity of the first reference battery cell and the target equalization capacity value of the first reference battery cell is used as a reference residual charging capacity;
for any other battery cell except the first reference battery cell, if the remaining charge capacity is not less than the reference remaining charge capacity, recording a target equalization capacity value of the any other battery cell as 0; if not, recording the difference value between the reference residual charging capacity and the residual charging capacity of any other battery monomer as the target equalizing capacity value of any other battery monomer;
and the balance control unit is used for discharging the battery monomer with the target balance electric quantity value not being 0 until the accumulated discharge electric quantity of each battery monomer is equal to the corresponding target balance electric quantity value.
9. The system of claim 8,
the estimation unit is further configured to: reading the stored electric quantity value when the battery pack is powered on and powered off last time, calculating the accumulated charge-discharge electric quantity value of the battery pack in real time by taking the read electric quantity value as an initial value, and storing the calculated last accumulated charge-discharge electric quantity value when the battery pack is powered off;
in terms of estimating the capacity of each of the battery cells, the estimating unit is specifically configured to:
during power-on, acquiring the state of charge (SOC) of the battery monomer i corresponding to the first target moment1,iAnd accumulated charging and discharging electric quantity value Q1(ii) a Meanwhile, acquiring the corresponding state of charge SOC of the battery monomer i at a second target moment2,iAnd accumulated charging and discharging electric quantity value Q2(ii) a The battery cell i represents any battery cell in the plurality of battery cells;
according to the SOC1,i、Q1、SOC2,iAnd Q2Estimating the capacity C of the battery cell ibat,i；
The first target time and the second target time are different power-on and power-on times, and the time difference between the first target time and the last power-off and power-off time is not less than a preset standing time threshold.
10. The system of claim 9,
acquiring the state of charge SOC corresponding to the battery monomer i at a first target moment1,iThe estimating unit is specifically configured to:
reading a terminal voltage value corresponding to the first target moment as a first open-circuit voltage value, and determining that the state of charge corresponding to the first open-circuit voltage value is the SOC according to the calibration relation of the state of charge and the open-circuit voltage1,i；
Obtaining the corresponding state of charge SOC of the battery monomer i at a second target moment2,iThe estimating unit is specifically configured to:
reading a terminal voltage value corresponding to the second target moment as a second open-circuit voltage value, and determining the state of charge corresponding to the second open-circuit voltage value as the SOC according to the calibration relation2,i。
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| CN110336343A (en) * | 2019-06-14 | 2019-10-15 | 安徽锐能科技有限公司 | A kind of SOC estimation method based on active equalization of battery |
| CN110474400B (en) * | 2019-09-12 | 2022-03-15 | 东软睿驰汽车技术（沈阳）有限公司 | Battery pack balancing method and device |
| CN111211594B (en) * | 2020-01-02 | 2024-03-15 | 安徽锐能科技有限公司 | Complementary equalization control method, circuit and storage medium considering temperature and SOH |
| CN111064261B (en) * | 2020-01-02 | 2024-01-12 | 安徽锐能科技有限公司 | Passive equalization strategy, device and storage medium considering temperature and SOH |
| CN111098758A (en) * | 2020-01-02 | 2020-05-05 | 安徽锐能科技有限公司 | Equalization method, circuit and storage medium based on SOH |
| CN111114382A (en) * | 2020-01-02 | 2020-05-08 | 安徽锐能科技有限公司 | SOH-based power supply type active equalization strategy, circuit and storage medium |
| CN111781529B (en) * | 2020-07-14 | 2023-06-27 | 上海理工大学 | Battery pack monomer capacity estimation method and device based on cloud data of electric automobile |
| CN114103729B (en) * | 2020-08-27 | 2023-06-13 | 比亚迪股份有限公司 | Method and device for balancing battery pack and electric automobile |
| CN112578286B (en) * | 2020-11-23 | 2022-11-22 | 经纬恒润(天津)研究开发有限公司 | Battery SOC estimation method and device |
| CN113839439B (en) * | 2021-08-27 | 2024-05-31 | 北京机械设备研究所 | Full-period battery pack balance control method, device and storage medium |
| CN115946572B (en) * | 2022-11-21 | 2023-06-30 | 上海玫克生储能科技有限公司 | Battery module capacity calculation and compensation control method, system, equipment and medium |
| CN116031974B (en) * | 2022-12-26 | 2023-09-12 | 鹏元晟高科技股份有限公司 | Balanced charging and discharging method and system for energy storage battery pack |
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Address after: 4 / F, building 1, No.14 Jiuxianqiao Road, Chaoyang District, Beijing 100020 Patentee after: Beijing Jingwei Hirain Technologies Co.,Inc. Address before: 8 / F, block B, No. 11, Anxiang Beili, Chaoyang District, Beijing 100101 Patentee before: Beijing Jingwei HiRain Technologies Co.,Ltd. |
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