CN109428355B - Battery equalization method, system, vehicle, storage medium and electronic device - Google Patents

Battery equalization method, system, vehicle, storage medium and electronic device Download PDF

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Publication number
CN109428355B
CN109428355B CN201710773455.0A CN201710773455A CN109428355B CN 109428355 B CN109428355 B CN 109428355B CN 201710773455 A CN201710773455 A CN 201710773455A CN 109428355 B CN109428355 B CN 109428355B
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battery
value
single battery
balanced
determining
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CN109428355A (en
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罗红斌
王超
沈晓峰
曾求勇
刘苑红
张祥
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BYD Co Ltd
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BYD Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

The present disclosure relates to a battery equalization method, a system, a vehicle, a storage medium, and an electronic device, the method comprising: acquiring the voltage change rate of a single battery to be balanced in a battery pack; acquiring a reference voltage change rate required by balancing; determining the target equalization duration of the single battery to be equalized according to the voltage change rate of the single battery to be equalized and the reference voltage change rate; and controlling the balance of the single battery to be balanced according to the target balancing duration. The target equalization duration according to the equalization process is calculated according to the difference value between the voltage change rate of the single battery to be equalized and the reference voltage change rate, so that the equalization process is more accurate, and the occurrence of over-equalization is avoided.

Description

Battery equalization method, system, vehicle, storage medium and electronic device
Technical Field
The present disclosure relates to the field of control technologies, and in particular, to a battery equalization method, a battery equalization system, a vehicle, a storage medium, and an electronic device.
Background
A large-capacity battery that provides power energy for an electric vehicle is often referred to as a power battery. The vehicle power battery is generally formed by connecting a plurality of single batteries in series to form a module. With the use of batteries, the difference between the single batteries is gradually enlarged, the consistency between the single batteries is poor, the capacity of the battery pack is limited due to the short plate effect of the batteries, the capacity of the battery pack cannot be fully exerted, and the whole capacity of the battery pack is reduced. On the other hand, the gradual expansion of the difference between the single batteries may cause overcharge of some single batteries, over-discharge of some single batteries, affect the service life of the batteries, damage the batteries, and generate a large amount of heat to cause combustion or explosion of the batteries.
Therefore, the method has very important significance for effectively and uniformly managing the power batteries of the electric automobile, being beneficial to improving the consistency of the batteries in the battery pack, reducing the capacity loss of the batteries, and prolonging the service life of the batteries and the driving range of the electric automobile.
At present, balancing management is performed on a battery pack, battery information of each single battery in the battery pack is usually acquired in real time, whether the single battery needs balancing or not is determined according to the acquired battery information, and when the single battery needs balancing, the single battery needing balancing is balanced. In the process of balancing the single batteries, if the balancing time of the single batteries is too long, the inconsistency of each single battery in the battery pack where the single batteries are located is increased, and the balancing efficiency is low; if the equalization time of the single battery is too short, the equalization effect cannot be achieved. Therefore, how to accurately determine the balancing time of the single battery needing balancing is a problem to be solved.
Disclosure of Invention
The purpose of the present disclosure is to provide a battery equalization method, system, vehicle, storage medium, and electronic device to optimize a battery equalization process.
In order to achieve the above object, a first aspect of the present disclosure provides a battery equalization method, including:
acquiring the voltage change rate of a single battery to be balanced in a battery pack;
acquiring a reference voltage change rate required by balancing;
determining the target equalization duration of the single battery to be equalized according to the voltage change rate of the single battery to be equalized and the reference voltage change rate;
and controlling the balance of the single battery to be balanced according to the target balancing duration.
A second aspect of the present disclosure provides a battery equalization system, the system comprising:
a balancing module, an acquisition module and a control module,
the acquisition module is used for: acquiring the voltage change rate of a single battery to be balanced in a battery pack;
the control module is used for: acquiring a reference voltage change rate required by balancing, and determining a target balancing duration of the single battery to be balanced according to the voltage change rate of the single battery to be balanced and the reference voltage change rate;
the equalization module is configured to: and balancing the single batteries to be balanced according to the target balancing duration.
A third aspect of the present disclosure provides a computer readable storage medium having stored thereon computer program instructions which, when executed by a processor, implement the method of the first aspect of the present disclosure.
A fourth aspect of the present disclosure provides an electronic device, comprising:
a computer-readable storage medium according to a third aspect of the disclosure; and
one or more processors to execute the program in the computer-readable storage medium.
A fifth aspect of the present disclosure provides a vehicle including: a battery pack and a battery equalization system according to the second aspect of the present disclosure.
According to the technical scheme, the target equalization time length of the single battery to be equalized is determined according to the voltage change rate and the reference voltage change rate of the single battery to be equalized in the battery pack, and then the single battery to be equalized is equalized according to the determined target equalization time length. The target equalization time length based on the equalization process is calculated according to the difference value between the voltage change rate of the single battery to be equalized and the reference voltage change rate, so that the equalization process is more accurate, and the situation that the equalization time length is too long or too short is avoided.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
fig. 1 is a schematic diagram of a battery equalization system according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a battery equalization system in which two single batteries share one equalization module according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a battery equalization system of another embodiment of the present disclosure;
fig. 4 is a schematic diagram of a battery equalization system in which two single batteries share one equalization module according to another embodiment of the present disclosure;
fig. 5 is a schematic flow chart of a battery equalization method according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of a voltage difference between a single battery to be equalized and a reference battery according to an embodiment of the disclosure;
fig. 7 is a schematic voltage difference diagram of a cell to be equalized and a reference cell according to another embodiment of the disclosure;
fig. 8 is an open circuit voltage OCV-remaining capacity SOC curve of a unit cell according to an embodiment of the present disclosure;
FIG. 9 is a schematic diagram of a battery internal resistance model of an embodiment of the present disclosure;
fig. 10 is a schematic diagram of an equalization module according to an embodiment of the present disclosure.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
Referring to fig. 1, a schematic diagram of a battery equalization system according to an embodiment of the present disclosure is shown. This battery equalizing system includes: the system comprises a control module 101, an acquisition module 102, an equalization module 103 and a battery pack 104.
In one embodiment, each cell corresponds to one acquisition module 102 and one equalization module 103. The acquisition module 102 and the equalization module 103 corresponding to the same single battery are respectively connected with the control module 101 through different control channels. The control module can comprise a control chip, the control chip is respectively connected with the acquisition module and the balance module corresponding to the same single battery through two pins, and the two pins correspond to the two channels one by one.
In this embodiment, the control module 101 controls the acquisition module 102 and the equalization module 103 to conduct in a time-sharing manner according to a unit cycle, and respectively performs acquisition of battery information and equalization of a battery, so that the acquisition of the battery information and the equalization are performed in a time-sharing manner. The influence of the equalizing current on the accuracy of battery information acquisition is avoided when the battery information acquisition and the equalization are simultaneously carried out.
In one embodiment, referring to fig. 1, each of the cells is connected to an acquisition module 102 and an equalization module 103, respectively. If the battery pack includes N single batteries, the number of the acquisition modules 102 is N, and the number of the equalization modules 103 is N, so that the control module 101 is connected to the N acquisition modules and the N equalization modules through 2 × N control channels, respectively.
In other embodiments, different cells may share an equalization module, for example, N cells in a battery pack, the same equalization module may be shared, or one equalization module may be shared for each predetermined number (e.g., 2, 3, or 5, etc.) of cells, and so on. When at least two single batteries in the multiple single batteries sharing one balancing module need to be balanced, the balancing module is alternately connected with each single battery in the at least two single batteries needing to be balanced in the balancing time interval of the unit cycle.
Referring to fig. 2, two single batteries share one balancing module, and when two single batteries sharing one balancing module need to be balanced, the balancing module is alternately connected with each single battery in a balancing period of a unit cycle. The alternate connection may be a connection that alternates according to a certain period. For example, referring to fig. 2, when the parallel switch 150 on the parallel branch 15 corresponding to one of the two single batteries 111 is closed for 2s under the control of the control module 14, the parallel switch 150 on the parallel branch 15 corresponding to the other of the two single batteries 111 is opened for 2s under the control of the control module 14. That is, the parallel switch 150 on the parallel branch 15 corresponding to each of the two single batteries 111 is switched from the closed state to the open state or from the open state to the closed state every two seconds in the equalization period. Therefore, on the basis of time-sharing conduction of the acquisition module and the equalization module, the single batteries sharing the same equalization module are alternately connected with the shared equalization module during the equalization time period, and equalization is realized.
Fig. 3 is a schematic structural diagram of a battery equalization system according to another embodiment of the present disclosure.
This battery equalizing system includes: a control module 301, an acquisition module 302, an equalization module 303, and a battery pack 304. The battery pack 304 includes a plurality of unit cells connected in series. The control module 301 is connected to the acquisition module 302 and the equalization module 303 corresponding to the same cell via a control channel 305. The control module is used for controlling the connection of the control module and the corresponding sampling module when the single battery connected with the control module is determined not to need balancing; or, the control module is further configured to multiplex the channels 305 in time division according to a unit period by the acquisition module and the equalization module when it is determined that the single battery connected to the control module needs equalization.
One unit period includes: an acquisition period and an equalization period. The control module 301 controls the acquisition module 302 to sample the battery information of the single battery in an acquisition time period to obtain the battery information of the single battery. The battery information includes at least one of: voltage, current, temperature, etc. In one embodiment, the battery information may include only the voltage value, and thus, the voltage performance parameter of the unit battery may be obtained. In another embodiment, the battery information may also include a voltage value, a current value, a temperature value, and the like, so as to obtain performance parameters such as SOC, internal resistance, voltage change rate, and the like of the single battery.
The control module 301 determines the single battery to be balanced, which needs to be balanced, according to the battery information of the single battery acquired by the acquisition module 302. For the single battery to be equalized which needs to be started, the control module 301 controls the equalization module corresponding to the single battery to be equalized, and equalizes the single battery to be equalized in an equalization time period.
Therefore, in the embodiment of the disclosure, the acquisition module and the balancing module share the same control channel, the control module controls the acquisition module and the balancing module, and the control channel is multiplexed in time according to a unit period, so that the influence of balancing current on the accuracy of battery information acquisition is avoided when the battery information acquisition and the balancing are performed simultaneously; on the other hand, compared with the embodiment shown in fig. 1, the requirement for the number of channels of the control module chip is reduced, and the hardware cost can be saved.
In one embodiment, a switch K is disposed in a control channel shared by the acquisition module and the equalization module, and the control module 301 is connected to the switch K and is connected to the acquisition module 302 or the equalization module 303 in a time-sharing manner by controlling the switch K. When the switch K is connected with the acquisition module 302, the control module 301 controls the acquisition module 302 to acquire battery information of the single battery in an acquisition period; when the switch K is connected to the balancing module 303, the control module 301 controls the balancing module 303 to balance the corresponding single battery.
In one embodiment, referring to fig. 3, each cell of the battery is connected to an acquisition module 302 and an equalization module 303, respectively. If the battery pack includes N single batteries, the number of the acquisition modules 302 is N, and the number of the equalization modules 303 is N, so that the control module 301 is connected to the acquisition modules and the equalization modules through N control channels.
In other embodiments, different cells may share an equalization module, for example, N cells in a battery pack, the same equalization module may be shared, or one equalization module may be shared for each predetermined number (e.g., 2, 3, or 5, etc.) of cells, and so on. When at least two single batteries in the multiple single batteries sharing one balancing module need to be balanced, the balancing module is alternately connected with each single battery in the at least two single batteries needing to be balanced in the balancing time interval of the unit cycle.
Referring to fig. 4, an exemplary schematic diagram of two unit cells sharing one balancing module is shown. When two single batteries sharing one balancing module need to be balanced, the balancing module is alternately connected with each single battery in the balancing time interval of the unit cycle. The alternate connection may be a connection that alternates according to a certain period. Therefore, on the basis of time-sharing conduction of the acquisition module and the equalization module, the single batteries sharing the same equalization module are alternately connected with the shared equalization module during the equalization time period, and equalization is realized.
In one embodiment, the collecting module may be a voltage collecting chip for collecting the voltage of the single battery during the collecting period.
Referring to fig. 5, based on the battery balancing system shown in any one of the embodiments of fig. 1, fig. 2, fig. 3, or fig. 4, the battery balancing method according to an embodiment of the present disclosure includes: in the step S52, in step S52,
in step S51, acquiring a voltage change rate of the single battery to be equalized in the battery pack;
in step S52, a reference voltage change rate required for equalization is acquired;
in step S53, determining a target equalization duration of the cell to be equalized according to the voltage change rate of the cell to be equalized and the reference voltage change rate;
in step S54, balancing of the single battery to be balanced is controlled according to the target balancing duration.
The voltage change rate of the unit cell may be a voltage change amount at which a unit change of a specified physical quantity of the unit cell occurs. For example, in the present disclosure, to charge or discharge a preset amount of electricity to or from a unit cell, a voltage change rate (dv/dq) of the unit cell; or, a preset time period for charging or discharging the single battery cell, and a voltage change rate (dv/dt) of the single battery cell will be described as an example.
In one embodiment, the step S51 is implemented in two ways, including but not limited to:
the first embodiment: charging or discharging unit electric quantity to each single battery in the battery pack; and for each single battery in the battery pack, determining the voltage change rate of the single battery as the change quantity of the load voltage value of the single battery along with the unit electric quantity change.
The second embodiment: charging or discharging each single battery in the battery pack for a unit time length; and for each single battery in the battery pack, determining the voltage change rate of the single battery as the change quantity of the voltage value of the single battery along with the unit time length of charging/discharging the single battery.
In one embodiment, obtaining the voltage change rate of each unit cell in the battery pack comprises:
in the charging or discharging process of the battery pack, the preset electric quantity charged or discharged to each single battery and the voltage change rate of each single battery are determined. The voltage change rate is a difference value between an initial terminal voltage before the single battery is charged or discharged with a preset electric quantity and a final terminal voltage after the single battery is charged or discharged with the preset electric quantity.
For each single battery in the battery pack, determining the voltage change rate of the single battery as the ratio of the voltage change rate of the single battery to the preset electric quantity.
In another embodiment, obtaining the voltage change rate of each unit cell in the battery pack includes:
in the charging or discharging process of the battery pack, the preset charging or discharging time length of each single battery and the voltage change rate of each single battery are determined. The voltage change rate is the difference value between the initial terminal voltage before the single battery is charged or discharged with the preset electric quantity and the final terminal voltage after the single battery is charged or discharged with the preset electric quantity;
for each single battery in the battery pack, determining the voltage change rate of the single battery as the ratio of the voltage change rate of the single battery to a preset time length.
In the charging or discharging process of the battery pack, the voltage and electric quantity change conditions of the single batteries are recorded, so that the voltage change rate of the single batteries can be obtained according to the voltage and electric quantity change conditions and the method.
In step S52, a reference voltage change rate is determined from the voltage change rate of each unit cell.
In one embodiment, the voltage change rate of any single cell in the battery pack may be used as the reference voltage change rate, for example, the voltage change rate of the 2 nd single cell in the battery pack may be used as the reference voltage change rate, or the voltage change rate of the single cell with the largest voltage change rate in the battery pack may be used as the reference voltage change rate, or the voltage change rate of the single cell with the smallest voltage change rate in the battery pack may be used as the reference voltage change rate, or the voltage change rate of the single cell with the lowest voltage change rate in the battery pack may be used as the reference voltage change rate (for the case where the battery pack includes an odd number of single cells).
In another embodiment, the reference voltage change rate may also be calculated according to the voltage change rate of each single battery in the battery pack, for example: the average value of the voltage change rates of the respective unit cells in the battery pack, or the average value of the voltage change rates of the two unit cells in the battery pack having the voltage change rate arranged at the middle (for the case where the battery pack includes an even number of unit cells).
Optionally, determining a target equalization duration of the single battery to be equalized according to the voltage change rate of the single battery to be equalized and the reference voltage change rate, where the determining includes:
determining the single battery with the minimum difference between the voltage change rate and the reference voltage change rate in the battery pack as a reference battery;
judging whether the initial end voltage of the single battery to be balanced is the same as the initial end voltage of the reference battery;
when the initial end voltage of the single battery to be balanced is the same as the initial end voltage of the reference battery, determining the target balancing duration according to the final end voltage of the single battery to be balanced and the final end voltage of the reference battery;
and when the initial end voltage of the single battery to be balanced is different from the initial end voltage of the reference battery, determining the target balancing time length according to the initial end voltage of the single battery to be balanced and the initial end voltage of the reference battery.
Determining the target equalization duration according to the initial terminal voltage of the single battery to be equalized and the initial terminal voltage of the reference battery, wherein the determining the target equalization duration comprises the following steps:
determining a first SOC value corresponding to the initial terminal voltage value of the reference battery according to the initial terminal voltage value of the reference battery and an open-circuit voltage OCV-remaining capacity SOC curve of the reference battery;
determining a second SOC value corresponding to the initial terminal voltage value of the single battery to be balanced according to the initial terminal voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length according to the first SOC value and the second SOC value.
Similarly, determining the target equalization duration according to the final end voltage of the single battery to be equalized and the final end voltage of the reference battery, including:
determining a third SOC value corresponding to the final terminal voltage value of the reference battery according to the final terminal voltage value of the reference battery and the OCV-SOC curve of the reference battery;
determining a fourth SOC value corresponding to the final end voltage value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length of the single battery to be equalized according to the third SOC value and the fourth SOC value.
In the embodiment of the present disclosure, the initial terminal voltage is a voltage detected when the battery pack starts charging or discharging, or a voltage of the unit battery detected at a certain set detection timing. The final terminal voltage is a voltage obtained by charging or discharging a preset amount of electricity to or from the single battery on the basis of the initial terminal voltage. Or the final terminal voltage is a voltage obtained by charging or discharging the single battery for a preset time length on the basis of the initial terminal voltage.
Referring to fig. 6, fig. 6 shows a case where the initial terminal voltage of the unit cell to be equalized and the initial terminal voltage of the reference cell are different. Referring to fig. 7, fig. 7 is a case where there is no difference between the initial terminal voltage of the unit cells to be equalized and the initial terminal voltage of the reference cell, in which case the rate of change of the voltage of the unit cells is mainly caused by the difference in the speed of change of the voltage during the charging or discharging process.
For the case shown in fig. 6, the single batteries are in different SOC intervals, the same voltage is changed, and the amount of electricity required to be charged or discharged is different. Therefore, the electric quantity difference of the two single batteries can be determined according to the initial end voltages of the two single batteries, and the target equalization duration of the single battery to be equalized is further determined according to the electric quantity difference of the two single batteries.
Specifically, a reference OCV value of the reference battery is determined according to an initial terminal voltage value of the reference battery and an internal resistance value of the reference battery;
determining an SOC value corresponding to the reference OCV value as the first SOC value according to the reference OCV value and an OCV-SOC curve of the reference battery;
determining an OCV value of the single battery to be balanced according to the initial end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
determining the SOC value corresponding to the OCV value of the single battery to be balanced as the second SOC value according to the OCV-SOC curve of the single battery to be balanced;
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the first and second SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
For the case shown in fig. 7, the target equalization time length of the single battery to be equalized may be determined according to the final terminal voltage of the single battery to be equalized and the final terminal voltage of the reference battery.
Specifically, a reference OCV value of the reference battery is determined according to a final terminal voltage value of the reference battery and an internal resistance value of the reference battery;
determining the SOC value corresponding to the reference OCV value as the third SOC value according to the reference OCV value and the OCV-SOC curve of the reference battery;
determining an OCV value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
and determining the SOC value corresponding to the OCV value of the single battery to be balanced as the fourth SOC value according to the OCV-SOC curve of the single battery to be balanced.
According to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the third and fourth SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
In one embodiment of the present disclosure, the OCV-SOC curve is obtained through measurement. For example, for a certain single battery, in the process of changing the SOC value from 0 to 100%, the open circuit voltage OCV of the primary battery is measured at certain SOC intervals, and then the OCV and the SOC corresponding to each point are in one-to-one correspondence to form the SOC-OCV curve of the single battery. Fig. 8 is a schematic diagram of an OCV-SOC curve of a unit cell.
The OCV value is an open circuit voltage value of the unit cell, and is different from a load voltage value. Referring to fig. 9 and equation (1), when the battery pack is in a discharging state or a charging state, the cell is equivalent to an ideal voltage source and is connected in series with the resistor R by using a cell internal resistance model. Then, for a single battery, the sampled voltage value V of the single battery can be obtained according to the formula (1)L(i.e., load voltage value) to open circuit voltage value:
OCV＝VL+I×R (1)
wherein, VLThe load voltage value collected by the collecting module in the collecting time period; i is the discharging current or the charging current collected by the collecting module in the collecting time period; and R is the internal resistance value of the single battery.
It should be understood that, when the open circuit voltage OCV is measured, the load voltage of the unit cell may be collected and then converted into the corresponding open circuit voltage OCV according to equation (1).
Therefore, the first SOC value, the second SOC value, the third SOC value and the fourth SOC value can be obtained according to the reference voltage value, the internal resistance value of the reference battery and the OCV-SOC curve corresponding to the reference battery.
After obtaining the first SOC-value and the second SOC-value, performing the steps of:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is the difference in SOC between a first SOC value and a second SOC value, CnThe available capacity of the single battery to be balanced;
and determining a target equalization time length according to the t ═ delta Q/I, wherein t is the target equalization time length, and I is the equalization current of the single battery to be equalized.
Similarly, after obtaining the third SOC value and the fourth SOC value, the following steps are performed:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is the difference in SOC between the third and fourth SOC values, CnThe available capacity of the single battery to be balanced;
and determining a target equalization time length according to the t ═ delta Q/I, wherein t is the target equalization time length, and I is the equalization current of the single battery to be equalized.
The reference voltage change rates are different, and the balancing process of the single batteries needing balancing is different. Hereinafter, the case where the reference voltage change rate is the minimum value, the maximum value, and the average value among the voltage change rates of the respective unit cells in the battery pack will be described.
1) In a case where the reference voltage change rate is the minimum value among the voltage change rates of the individual battery cells in the battery pack, the determining a voltage change rate difference between the voltage change rate of the at least one battery cell and the reference voltage change rate required for the equalization determination includes: determining a voltage change rate difference value between the voltage change rate of the following single batteries and a reference voltage change rate required by the balance judgment:
the single battery with the largest voltage change rate in the battery pack; or
And a cell other than the cell having the minimum voltage change rate in the battery pack.
Correspondingly, after determining that the single battery needing to be balanced is the single battery with the voltage change rate difference value larger than or equal to the balance starting threshold value in the at least one single battery, the method further comprises the following steps: when the battery pack is in a charging process, controlling the single battery with the voltage change rate difference value larger than or equal to the balance starting threshold value in the at least one single battery to discharge; and when the battery pack is in the discharging process, controlling the charging of the single battery of which the voltage change rate difference is greater than or equal to the balance starting threshold value in the at least one single battery.
Specifically, when the reference voltage change rate is the minimum value of the voltage change rates of the individual batteries in the battery pack, only the voltage change rate of the individual battery with the largest voltage change rate in the battery pack may be subtracted from the reference voltage change rate, so as to determine whether the individual battery with the largest voltage change rate in the battery pack is the individual battery that needs to be balanced. This embodiment can only determine if one cell needs to be balanced.
When the reference voltage change rate is the minimum value among the voltage change rates of the single batteries in the battery pack, the voltage change rates of the other single batteries except the single battery with the minimum voltage change rate in the battery pack can be differentiated from the reference voltage change rate, so as to determine whether the other single batteries except the single battery with the minimum voltage change rate in the battery pack are the single batteries needing to be balanced. This embodiment is a batch determination method, and can determine whether or not the other cells except the cell with the smallest voltage change rate in the battery pack are the cells that need to be balanced at one time.
When the reference voltage change rate is the minimum value of the voltage change rates of the single batteries in the battery pack, the process of balancing the single batteries needing balancing is as follows:
considering the large voltage change rate, this may be caused by the large internal resistance of the battery. Another aspect may be due to the presence of a capacity difference, i.e., an initial difference in SOC. The battery with large internal resistance is seriously aged, and the voltage of the battery rises quickly in the charging process, so that the battery pack discharges the single batteries needing to be balanced when in the charging process; considering that the battery with large internal resistance is seriously aged and the voltage thereof is rapidly reduced in the discharging process, the battery pack charges the single batteries requiring the equalization when the battery pack is in the discharging process.
2) In a case where the reference voltage change rate is a maximum value among the voltage change rates of the individual battery cells in the battery pack, the determining a voltage change rate difference between the voltage change rate of the at least one battery cell and a reference voltage change rate required for the equalization determination includes: determining a voltage change rate difference value between the voltage change rate of the following single batteries and a reference voltage change rate required by the balance judgment:
the single battery with the minimum voltage change rate in the battery pack; or
And the other single batteries except the single battery with the voltage change rate of the maximum value in the battery pack.
Correspondingly, after determining that the single battery needing to be balanced is the single battery with the voltage change rate difference value larger than or equal to the balance starting threshold value in the at least one single battery, the method further comprises the following steps: when the battery pack is in a charging process, controlling the charging of the single battery of which the voltage change rate difference is greater than or equal to the equalizing starting threshold value in the at least one single battery; and when the battery pack is in the discharging process, controlling the discharging of the single battery of which the voltage change rate difference is greater than or equal to the balance starting threshold value in the at least one single battery.
Specifically, when the reference voltage change rate is the maximum value of the voltage change rates of the individual batteries in the battery pack, only the voltage change rate of the individual battery with the smallest voltage change rate in the battery pack may be subtracted from the reference voltage change rate, so as to determine whether the individual battery with the smallest voltage change rate in the battery pack is the individual battery requiring equalization. This embodiment can only determine if one cell needs to be balanced.
When the reference voltage change rate is the maximum value among the voltage change rates of the single batteries in the battery pack, the voltage change rates of the other single batteries except the single battery with the maximum voltage change rate in the battery pack can be differentiated from the reference voltage change rate, so as to determine whether the other single batteries except the single battery with the maximum voltage change rate in the battery pack are the single batteries needing to be balanced. This embodiment is a batch determination method, and can determine whether or not the other cells except the cell having the largest voltage change rate in the battery pack are the cells requiring equalization at one time.
When the reference voltage change rate is the maximum value of the voltage change rates of the single batteries in the battery pack, the process of balancing the single batteries needing balancing is as follows:
considering the large voltage change rate, this may be caused by the large internal resistance of the battery. Another aspect may be due to the presence of a capacity difference, i.e., an initial difference in SOC. The battery with large internal resistance is seriously aged, and the voltage of the battery rises quickly in the charging process, so that the single batteries needing to be balanced are charged when the battery pack is in the charging process; considering that the battery with large internal resistance is seriously aged and the voltage thereof is rapidly reduced in the discharging process, the battery pack discharges the single batteries needing to be balanced when in the discharging process.
3) In a case where the reference voltage change rate is an average value of the voltage change rates of the individual cells in the battery pack, the determining a voltage change rate difference between the voltage change rate of the at least one cell and a reference voltage change rate required for the equalization determination includes: and determining a voltage change rate difference value between the voltage change rate of each single battery in the battery pack and the reference voltage change rate.
Correspondingly, after determining that the single battery needing to be balanced is the single battery with the voltage change rate difference value larger than or equal to the balance starting threshold value in the at least one single battery, the method further comprises the following steps:
when the battery pack is in a charging process, controlling the single batteries with the voltage change rates smaller than the average value in the single batteries to be balanced to charge, and controlling the single batteries with the voltage change rates larger than the average value in the single batteries to be balanced to discharge;
and when the battery pack is in the discharging process, controlling the single batteries with the voltage change rates smaller than the average value in the single batteries needing to be balanced to discharge, and controlling the single batteries with the voltage change rates larger than the average value in the single batteries needing to be balanced to charge.
Specifically, when the reference voltage change rate is an average value of the voltage change rates of the individual batteries in the battery pack, the voltage change rate of each individual battery in the battery pack may be different from the reference voltage change rate, so as to determine whether each individual battery in the battery pack is an individual battery that needs to be balanced. The embodiment is a batch judgment mode, and can judge whether each single battery in the battery pack is a single battery needing to be balanced at one time.
When the reference voltage change rate is the average value of the voltage change rates of the single batteries in the battery pack, the process of balancing the single batteries needing balancing is as follows:
considering the large voltage change rate, this may be caused by the large internal resistance of the battery. Another aspect may be due to the presence of a capacity difference, i.e., an initial difference in SOC. The battery with large internal resistance is seriously aged, the voltage of the battery rises quickly in the charging process, and the voltage of the battery drops quickly in the discharging process, so that when the battery pack is in the charging process, the battery pack charges the single battery with the voltage change rate smaller than the average value of the voltage change rate in the single battery needing to be balanced, and discharges the single battery with the voltage change rate larger than the average value of the voltage change rate in the single battery needing to be balanced; similarly, when the battery pack is in the discharging process, the single batteries with the voltage change rate smaller than the average value of the voltage change rate in the single batteries needing to be balanced are discharged, and the single batteries with the voltage change rate larger than the average value of the voltage change rate in the single batteries needing to be balanced are charged.
It should be understood that if it is determined that there is no single battery requiring equalization, it is continuously determined whether there is a single battery requiring equalization according to the voltage change rate of at least one single battery in the battery pack. When it is determined that no single battery needs to be balanced, the control module does not act, so that the balancing module corresponding to any battery is not started.
Referring to fig. 10, a schematic diagram of an equalization module according to an embodiment of the disclosure is shown. And controlling the single batteries to be balanced, wherein the balancing judgment needs to be combined. According to the step of equalization judgment, whether the equalization mode of the single battery to be equalized is passive equalization (namely, the single battery to be equalized is discharged) or active equalization (namely, the single battery to be equalized is charged) is determined, and the corresponding equalization module is conducted.
Referring to fig. 10, for passive equalization, the equalization module includes: and each single battery corresponds to one equalizing module, namely two ends of each single battery are connected with one resistor in parallel.
For the single battery to be balanced which needs to be passively balanced, the control module controls the conduction of a parallel loop between the single battery to be balanced and the corresponding resistor of the single battery to be balanced so as to execute the passive balancing of the single battery. Referring to fig. 10, the control module controls the switch module 812 to be turned on, so as to achieve the conduction of the parallel loop between the single battery to be equalized and the corresponding resistor.
The resistor 811 may be a fixed resistor or a variable resistor. In one embodiment, the resistor 811 may be a positive temperature coefficient thermistor, which may change with the temperature change, so as to adjust the balancing current generated during balancing, thereby automatically adjusting the heat generation amount of the battery balancing system, and finally effectively controlling the temperature of the battery balancing system.
Referring to fig. 10, for active equalization, the equalization module includes a charging branch 94 connected in parallel with each battery cell 95 in the battery pack, the charging branches 94 correspond to the battery cells 95 one by one, and each charging branch 94 is connected to the generator 92, and the generator 92 is mechanically connected to the engine 91 through a gear.
For the single battery to be equalized which needs to be actively equalized, the control module controls the charging branch 94 corresponding to the single battery to be equalized to be conducted. When the engine 91 rotates, the generator 92 is driven to generate electricity, so that the electricity generated by the generator 92 is transmitted to the single battery to be balanced, and the electricity of the single battery to be balanced is increased.
Referring to fig. 10, when the generator 92 is an alternator, the balancing module further comprises a rectifier 93 in series with the generator 92, each charging branch 94 being in series with the rectifier 93. After the alternating current generated by the generator 92 is converted into direct current by the rectifier 93, the generator 92 can be used for charging the single battery to be equalized.
Referring to fig. 10, the control module may control the switch 96 corresponding to the single battery to be equalized to be turned on, so that the charging branch corresponding to the single battery to be equalized is turned on, and active equalization of the single battery to be equalized is performed.
In other embodiments, in addition to the charging of the single batteries by the generator shown in fig. 10, the single batteries to be equalized may also be charged by the starting battery in the entire vehicle.
In another embodiment, in addition to the parallel resistor and the single battery to be equalized as shown in fig. 10, the single battery to be equalized may be connected in parallel with a starting battery of the whole vehicle, and the electric quantity discharged by the single battery to be equalized is charged into the starting battery, so that the equalization of the single battery to be equalized is realized while energy waste is effectively avoided.
As described above, in the embodiment of the present disclosure, a plurality of single batteries may share one balancing module, and when at least two single batteries among a plurality of single batteries sharing one balancing module need to be balanced, the balancing module is alternately connected to each single battery among the at least two single batteries needing to be balanced, and the balancing module performs balancing respectively.
Correspondingly, the embodiment of the disclosure also provides a vehicle, which comprises the battery equalization system.
Accordingly, the disclosed embodiments also provide a computer readable storage medium, on which computer program instructions are stored, and the program instructions, when executed by a processor, implement the above battery equalization method.
Correspondingly, the embodiment of the present disclosure further provides an electronic device, including: the aforementioned computer-readable storage medium; and one or more processors for executing the program in the computer-readable storage medium.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

Claims (31)

1. A method of balancing a battery, comprising:
acquiring the voltage change rate of a single battery to be balanced in a battery pack;
acquiring a reference voltage change rate required by balancing;
determining the target equalization duration of the single battery to be equalized according to the voltage change rate of the single battery to be equalized and the reference voltage change rate;
controlling the balance of the single batteries to be balanced according to the target balancing duration,
determining a target equalization duration of the single battery to be equalized according to the voltage change rate of the single battery to be equalized and the reference voltage change rate, wherein the determining the target equalization duration of the single battery to be equalized comprises the following steps:
determining the single battery with the minimum difference between the voltage change rate and the reference voltage change rate in the battery pack as a reference battery;
judging whether the initial end voltage of the single battery to be balanced is the same as the initial end voltage of the reference battery;
and when the initial end voltage of the single battery to be equalized is the same as the initial end voltage of the reference battery, determining the target equalization duration according to the final end voltage of the single battery to be equalized and the final end voltage of the reference battery.
2. The method according to claim 1, wherein after determining whether the initial terminal voltage of the single battery to be equalized is the same as the initial terminal voltage of the reference battery, the method further comprises:
and when the initial end voltage of the single battery to be balanced is different from the initial end voltage of the reference battery, determining the target balancing time length according to the initial end voltage of the single battery to be balanced and the initial end voltage of the reference battery.
3. The method as claimed in claim 2, wherein the determining the target equalization duration according to the initial terminal voltage of the single battery to be equalized and the initial terminal voltage of the reference battery comprises:
determining a first SOC value corresponding to the initial terminal voltage value of the reference battery according to the initial terminal voltage value of the reference battery and an open-circuit voltage OCV-remaining capacity SOC curve of the reference battery;
determining a second SOC value corresponding to the initial terminal voltage value of the single battery to be balanced according to the initial terminal voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length according to the first SOC value and the second SOC value.
4. The method as claimed in claim 3, wherein said determining a first SOC value corresponding to an initial terminal voltage value of said reference battery from said initial terminal voltage value of said reference battery and an OCV-SOC curve of said reference battery comprises:
determining a reference OCV value of the reference battery according to the initial terminal voltage value of the reference battery and the internal resistance value of the reference battery;
determining an SOC value corresponding to the reference OCV value as the first SOC value according to the reference OCV value and an OCV-SOC curve of the reference battery;
determining a second SOC value corresponding to the initial terminal voltage value of the single battery to be equalized according to the initial terminal voltage value of the single battery to be equalized and the OCV-SOC curve corresponding to the single battery to be equalized, wherein the determining step comprises the following steps:
determining an OCV value of the single battery to be balanced according to the initial end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
and determining the SOC value corresponding to the OCV value of the single battery to be balanced as the second SOC value according to the OCV-SOC curve of the single battery to be balanced.
5. The method of claim 4, wherein determining the target equalization duration based on the first SOC value and the second SOC value comprises:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the first and second SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
6. The method as claimed in claim 1, wherein determining the target equalization duration according to the final terminal voltage of the single battery to be equalized and the final terminal voltage of the reference battery comprises:
determining a third SOC value corresponding to the final terminal voltage value of the reference battery according to the final terminal voltage value of the reference battery and the OCV-SOC curve of the reference battery;
determining a fourth SOC value corresponding to the final end voltage value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length of the single battery to be equalized according to the third SOC value and the fourth SOC value.
7. The method as claimed in claim 6, wherein said determining a third SOC value corresponding to the final terminal voltage value of the reference battery according to the final terminal voltage value of the reference battery and an OCV-SOC curve of the reference battery comprises:
determining a reference OCV value of the reference battery according to the final terminal voltage value of the reference battery and the internal resistance value of the reference battery;
determining the SOC value corresponding to the reference OCV value as the third SOC value according to the reference OCV value and the OCV-SOC curve of the reference battery;
determining a fourth SOC value corresponding to the final end voltage value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced, wherein the fourth SOC value comprises the following steps:
determining an OCV value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
and determining the SOC value corresponding to the OCV value of the single battery to be balanced as the fourth SOC value according to the OCV-SOC curve of the single battery to be balanced.
8. The method of claim 7, wherein determining the target equalization duration based on the third SOC value and the fourth SOC value comprises:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the third and fourth SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
9. The method according to claim 1, wherein the obtaining of the voltage change rate of the single battery to be equalized in the battery pack comprises:
charging or discharging unit electric quantity to the single battery to be balanced;
and determining the voltage change rate of the single battery to be balanced as the variable quantity generated by the unit electric quantity along with the change of the electric quantity of the load voltage value of the single battery.
10. The method according to claim 1, wherein obtaining the voltage change rate of the single battery to be equalized in the battery pack comprises:
charging or discharging the single battery to be equalized for a unit time length;
and determining the voltage change rate of the single battery to be equalized as the change quantity of the voltage value of the single battery along with the unit time length of charging/discharging the single battery.
11. The method of claim 1, wherein obtaining the reference voltage change rate required for equalization comprises:
determining the minimum voltage change rate value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate; or,
determining the maximum voltage change rate value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate; or,
and determining the average value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate.
12. The method according to any one of claims 1-11, further comprising:
and determining the single batteries to be balanced from the battery pack according to battery parameter information of each single battery in the battery pack, wherein the battery parameter information comprises at least one of a load voltage value, an SOC value, an internal resistance value, a self-discharge rate value, an electric quantity change rate and a time change rate, the electric quantity change rate is the electric quantity required to be charged or discharged by changing the load voltage value of the single battery by a unit value, and the time change rate is the charging duration or the discharging duration required by changing the load voltage value of the single battery by the unit value.
13. A battery equalization system, comprising:
a balancing module, an acquisition module and a control module,
the acquisition module is used for: acquiring the voltage change rate of a single battery to be balanced in a battery pack;
the control module is used for: acquiring a reference voltage change rate required by balancing, and determining a target balancing duration of the single battery to be balanced according to the voltage change rate of the single battery to be balanced and the reference voltage change rate;
the equalization module is configured to: balancing the single batteries to be balanced according to the target balancing duration,
wherein the control module is configured to:
determining the single battery with the minimum difference between the voltage change rate and the reference voltage change rate in the battery pack as a reference battery;
judging whether the initial end voltage of the single battery to be balanced is the same as the initial end voltage of the reference battery;
and when the initial end voltage of the single battery to be equalized is the same as the initial end voltage of the reference battery, determining the target equalization duration according to the final end voltage of the single battery to be equalized and the final end voltage of the reference battery.
14. The battery equalization system of claim 13, wherein the control module is further configured to:
and when the initial end voltage of the single battery to be balanced is different from the initial end voltage of the reference battery, determining the target balancing time length according to the initial end voltage of the single battery to be balanced and the initial end voltage of the reference battery.
15. The battery equalization system of claim 14, wherein the control module is configured to:
determining a first SOC value corresponding to the initial terminal voltage value of the reference battery according to the initial terminal voltage value of the reference battery and an open-circuit voltage OCV-remaining capacity SOC curve of the reference battery;
determining a second SOC value corresponding to the initial terminal voltage value of the single battery to be balanced according to the initial terminal voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length according to the first SOC value and the second SOC value.
16. The battery equalization system of claim 15, wherein the control module is configured to:
determining a reference OCV value of the reference battery according to the initial terminal voltage value of the reference battery and the internal resistance value of the reference battery;
determining an SOC value corresponding to the reference OCV value as the first SOC value according to the reference OCV value and an OCV-SOC curve of the reference battery;
determining an OCV value of the single battery to be balanced according to the initial end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
and determining the SOC value corresponding to the OCV value of the single battery to be balanced as the second SOC value according to the OCV-SOC curve of the single battery to be balanced.
17. The battery equalization system of claim 16, wherein the control module is configured to:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the first and second SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
18. The battery equalization system of claim 13, wherein the control module is configured to:
determining a third SOC value corresponding to the final terminal voltage value of the reference battery according to the final terminal voltage value of the reference battery and the OCV-SOC curve of the reference battery;
determining a fourth SOC value corresponding to the final end voltage value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the OCV-SOC curve corresponding to the single battery to be balanced;
and determining the target equalization time length of the single battery to be equalized according to the third SOC value and the fourth SOC value.
19. The battery equalization system of claim 18, wherein the control module is configured to:
determining a reference OCV value of the reference battery according to the final terminal voltage value of the reference battery and the internal resistance value of the reference battery;
determining the SOC value corresponding to the reference OCV value as the third SOC value according to the reference OCV value and the OCV-SOC curve of the reference battery;
determining an OCV value of the single battery to be balanced according to the final end voltage value of the single battery to be balanced and the internal resistance value of the single battery to be balanced;
and determining the SOC value corresponding to the OCV value of the single battery to be balanced as the fourth SOC value according to the OCV-SOC curve of the single battery to be balanced.
20. The battery equalization system of claim 19, wherein the control module is configured to:
according to Δ Q ═ Δ SOC × CnDetermining a difference in electrical quantities, where Δ Q is the difference in electrical quantities, Δ SOC is a difference in SOC between the third and fourth SOC values, and CnThe available capacity of the single battery to be balanced is obtained;
and determining the target balancing time length according to the t ═ delta Q/I, wherein t is the target balancing time length, and I is the balancing current of the single battery to be balanced.
21. The battery equalization system of claim 13, wherein the acquisition module is configured to:
charging or discharging unit electric quantity to the single battery to be balanced;
and determining the voltage change rate of the single battery to be balanced as the variable quantity generated by the unit electric quantity along with the change of the electric quantity of the load voltage value of the single battery.
22. The battery equalization system of claim 13, wherein the acquisition module is configured to:
charging or discharging the single battery to be equalized for a unit time length;
and determining the voltage change rate of the single battery to be equalized as the change quantity of the voltage value of the single battery along with the unit time length of charging/discharging the single battery.
23. The battery equalization system of claim 13, wherein the control module is configured to:
determining the minimum voltage change rate value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate; or,
determining the maximum voltage change rate value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate; or,
and determining the average value of the voltage change rate values of the single batteries in the battery pack as the reference voltage change rate.
24. The battery equalization system of any of claims 13-23, wherein the control module is configured to:
and determining the single batteries to be balanced from the battery pack according to battery parameter information of each single battery in the battery pack, wherein the battery parameter information comprises at least one of a load voltage value, an SOC value, an internal resistance value, a self-discharge rate value, an electric quantity change rate and a time change rate, the electric quantity change rate is the electric quantity required to be charged or discharged by changing the load voltage value of the single battery by a unit value, and the time change rate is the charging duration or the discharging duration required by changing the load voltage value of the single battery by the unit value.
25. The battery equalization system of claim 13, wherein the control module is connected to the acquisition module and the equalization module corresponding to the same cell through a channel, and the control module is configured to control the control module to connect to the corresponding sampling module when it is determined that the cell connected to the control module does not need equalization; or,
the control module is further used for multiplexing the channels in a time-sharing manner by the acquisition module and the balancing module when the single battery connected with the control module needs to be balanced.
26. The battery equalization system of claim 25, wherein the control module comprises a control chip, and the control chip is connected to the acquisition module and the equalization module corresponding to the same cell through one pin and the one channel.
27. The battery equalization system of claim 13, wherein the control module is connected to the acquisition module and the equalization module corresponding to the same cell through two channels.
28. The battery equalization system of claim 27, wherein the control module comprises a control chip, the control chip is connected to the acquisition module and the equalization module corresponding to the same cell through two pins, and the two pins are in one-to-one correspondence with the two channels.
29. A computer-readable storage medium, on which computer program instructions are stored, which program instructions, when executed by a processor, implement the method of any of claims 1-12.
30. An electronic device, comprising:
the computer-readable storage medium recited in claim 29; and
one or more processors to execute the program in the computer-readable storage medium.
31. A vehicle, characterized in that the vehicle comprises: a battery pack and a battery equalization system as claimed in any of claims 13-28.
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