CN116315199B - Battery active equalization control method, device and system - Google Patents

Battery active equalization control method, device and system Download PDF

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Publication number
CN116315199B
CN116315199B CN202310562858.6A CN202310562858A CN116315199B CN 116315199 B CN116315199 B CN 116315199B CN 202310562858 A CN202310562858 A CN 202310562858A CN 116315199 B CN116315199 B CN 116315199B
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China
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cell
capacitor
battery
resistor
switch
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Chinese (zh)
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CN116315199A (en
Inventor
朱岩
王忠瑞
任政
裴景斌
孙杰
佟勇
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Beijing Zhongneng Situo Technology Co ltd
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Beijing Zhongneng Situo Technology Co ltd
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    • 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
    • H01M10/4207—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells 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
    • H01M10/4264—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing with capacitors
    • 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
    • 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
    • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • 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

Abstract

A battery active equalization control method, device and system belong to the field of battery equalization control. The method comprises the following steps: performing pairwise grouping on n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups, wherein n is an even number; based on the sequence of the voltage difference in the groups from large to small, each cell is controlled to be connected with the same bridging capacitor respectively, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and balanced control of two cells in each cell group is realized. The method has the advantages that the total capacity of the battery cell basically keeps unchanged, the complexity of hardware implementation is reduced, the pertinence of battery cell balance control is stronger, and the operation is simpler.

Description

Battery active equalization control method, device and system
Technical Field
The present invention relates to the field of battery equalization control, and in particular, to a method, an apparatus, and a system for active battery equalization control.
Background
The new energy battery, such as a lithium ion battery, is generally formed by connecting a plurality of electric cores in series. Because of inconsistent performances of each battery cell in the single battery caused by the production process or the factors of the battery cells, the single battery shows different characteristics such as capacity, internal resistance, self-discharge rate and the like in the charge and discharge process. The battery pack is largely lost due to the inconsistency of the individual batteries, and is further deteriorated with the lapse of time, and the deterioration rate can be reduced by equalizing the battery cells by the BMS (Battery Management System ).
Currently, the common cell balancing strategies mainly include:
1. passive equalization: the resistors are connected in parallel at the two ends of each cell in the battery, so that the energy of the high-voltage or high-charge cell is consumed, and the purpose of reducing the difference between different cells is achieved;
2. multi-capacitance active equalization: and respectively carrying out balanced control on the battery cells through a plurality of capacitors.
The passive equalization discharges the high-voltage battery cells through the resistor, so that the voltage difference among the battery cells is kept consistent, the voltage and the capacity of the battery cells are kept downwards in the mode, and redundant energy of the battery cells cannot be discharged and is lost in a thermal mode; the multi-capacitance equalization mode has high hardware complexity and high realization cost.
Disclosure of Invention
Object of the Invention
The invention aims to provide a battery active equalization control method, device and system, the total capacity of battery cells is basically kept unchanged, all the battery cells are connected with the same bridging capacitor, the complexity of hardware implementation is reduced, the pertinence of battery cell equalization control is stronger, and the operation is simpler.
Technical proposal
To solve the above problems, a first aspect of the present invention provides a battery active equalization control method, including:
S1: performing pairwise grouping on n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
s2: based on the sequence of the voltage difference in the groups from large to small, each cell is controlled to be connected with the same bridging capacitor respectively, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and balanced control of two cells in each cell group is realized.
Specifically, the grouping of n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups includes:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
Specifically, any one of the n electric cores is connected with a switch circuit; the method for controlling the balance control of the two cells in each cell group comprises the steps of controlling each cell group to be connected with the same bridging capacitor based on the sequence of the large-to-small voltage difference in the group, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and realizing the balance control of the two cells in each cell group, and the method comprises the following steps:
Sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
after the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
after discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
Further, the connection between the cell with larger voltage and the bridging capacitor is disconnected; and/or
Disconnecting the cell with smaller voltage from the crossover capacitor, and then further comprising:
transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so as to enable the jumper capacitor to be connected into the detection circuit;
and acquiring the voltage signal of the cross-over capacitor sent by the detection circuit and determining the voltage value of the corresponding battery cell according to the acquired voltage signal of the cross-over capacitor.
Further, the control method further comprises the following steps:
and (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
Further, after the balancing control is performed on the to-be-balanced battery cell group, the method further includes:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
In a second aspect of the present invention, there is provided a battery active equalization control device comprising:
the grouping unit is used for grouping n cells connected in series in the battery in pairs according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
And the control unit is used for controlling each cell to be connected with the same bridging capacitor respectively based on the sequence of the large-voltage difference in the groups, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, thereby realizing balanced control of two cells in each cell group.
Specifically, the grouping unit is configured to:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
Specifically, any one of the n electric cores is connected with a switch circuit, and the control unit is used for:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
After the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
after discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
Further, the control unit is further configured to:
transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so as to enable the jumper capacitor to be connected into the detection circuit;
the grouping unit is further configured to obtain the voltage signal of the cross-over capacitor sent by the detection circuit, and determine a voltage value of the corresponding battery cell according to the obtained voltage signal of the cross-over capacitor.
Further, the grouping unit is configured to:
And (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
Further, the control unit is further configured to:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
In a third aspect of the present invention, there is provided a battery active equalization control system, comprising:
active equalization control means for executing the control method of any one of the above;
the bridging capacitor is used for connecting or disconnecting with each cell group through the switching circuit;
and the switching circuit is used for receiving the switch control signal sent by the active equalization control device and connecting the corresponding battery cell group with the bridging capacitor according to the switch control signal.
Specifically, the active equalization control device includes:
the grouping unit is used for grouping n cells connected in series in the battery in pairs according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
and the control unit is used for controlling each cell to be connected with the same bridging capacitor respectively based on the sequence of the large-voltage difference in the groups, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, thereby realizing balanced control of two cells in each cell group.
Specifically, the grouping unit is configured to:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
Specifically, any one of the n electric cores is connected with a switch circuit, and the control unit is used for:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
after the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
After discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
Further, the control unit is further configured to:
transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so as to enable the jumper capacitor to be connected into the detection circuit;
the grouping unit is further configured to obtain the voltage signal of the cross-over capacitor sent by the detection circuit, and determine a voltage value of the corresponding battery cell according to the obtained voltage signal of the cross-over capacitor.
Further, the grouping unit is configured to:
and (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
Further, the control unit is further configured to:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
Specifically, the switching circuit comprises n switching circuits corresponding to n electric cores one by one;
For any battery core, if the battery core is the first battery core, one end of a first switch module of the battery core is connected with the positive electrode of the battery core, and the other end of the first switch module of the battery core is connected with one end of the bridging capacitor; the negative electrode of the battery cell is grounded, and the other end of the bridging capacitor is grounded; the control end of the first switch module is used for receiving a switch control signal sent by the active equalization control device and controlling the connection or disconnection of the battery cell and the bridging capacitor;
for any one of the electric cores, if the electric core is a non-initial electric core, the switch circuit of the any electric core is composed of a first switch module of the electric core and a second switch module of the previous electric core adjacent to the electric core; the first switch module and the second switch module in the switch circuit of any cell are connected in the following manner:
one end of the first switch module is connected with the positive electrode of the battery cell, and the other end of the first switch module is connected with one end of the bridging capacitor; one end of the second switch module is connected with the negative electrode of the battery cell, and the other end of the second switch module is connected with the other end of the bridging capacitor;
the control end of the first switch module and the control end of the second switch module are respectively connected with the output end of the active equalization control device; the first switch module and the second switch module are used for being closed under a switch control signal sent by the active equalization control device so as to enable the battery cell to be connected with the bridging capacitor.
Specifically, the switch module is a triode switch circuit and/or a relay switch circuit.
Specifically, the first switch module comprises an NPN type triode, a first PNP type triode, a second resistor, a third resistor and a fourth resistor, wherein a base electrode and an emitter electrode of the NPN type triode are respectively connected with an output end of the active equalization control device, a collector electrode of the NPN type triode is connected with a base electrode of the first PNP type triode through the second resistor, is connected with a base electrode of the second PNP type triode through the third resistor, is respectively connected with an excitation electrode of the first PNP type triode and an excitation electrode of the second PNP type triode through the fourth resistor, a collector electrode of the first PNP type triode is connected with a corresponding electric core, and a collector electrode of the second PNP type triode is connected with the bridging capacitor; the second switch module is identical to the first switch module in structure.
Further, the system also comprises a detection switch circuit and a detection circuit, wherein the detection switch circuit is used for receiving a detection switch control signal sent by the active equalization control device so as to connect or disconnect the detection circuit with the bridging capacitor; the detection circuit is used for sending the voltage signal of the cross-over capacitor to the active equalization control device.
The detection switching circuit comprises two detection switching modules, the two detection switching modules are connected with two ends of the bridging capacitor in a one-to-one correspondence mode, the detection switching modules comprise a fifth resistor, an NPN triode, a PNP triode and a sixth resistor, wherein an emitter of the NPN triode is grounded, a base of the NPN triode is connected with a collector of the PNP triode through the fifth resistor, a collector of the NPN triode is connected with one end of the bridging capacitor, a collector of the PNP triode is grounded through the sixth resistor, and a base and an emitter of the PNP triode are respectively connected with an output end of the active equalization control device.
Specifically, the detection circuit comprises an operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor, wherein a first input end of the operational amplifier is connected between two first resistors connected in parallel with the capacitor and is grounded through the seventh resistor;
the second input end of the operational amplifier is grounded through an eighth resistor and is connected with the output end of the operational amplifier through a ninth resistor;
And the output end of the operational amplifier is connected with the input end of the active equalization control device.
In a fourth aspect of the invention, an electronic device is provided that includes a memory and a processor;
the memory is used for storing one or more computer instructions;
the processor is configured to execute the one or more computer instructions to:
s1: performing pairwise grouping on n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
s2: based on the sequence of the voltage difference in the groups from large to small, each cell is controlled to be connected with the same bridging capacitor respectively, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and balanced control of two cells in each cell group is realized.
Specifically, the grouping of n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups includes:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
And determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
Specifically, any one of the n electric cores is connected with a switch circuit; the method for controlling the balance control of the two cells in each cell group based on the sequence of the large-to-small voltage difference in the group comprises the following steps of:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
after the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
After discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
Further, the connection between the cell with larger voltage and the bridging capacitor is disconnected; and/or
Disconnecting the cell with smaller voltage from the crossover capacitor, and then further comprising:
transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so that the jumper capacitor is connected to the detection circuit;
and acquiring the voltage signal of the cross-over capacitor sent by the detection circuit and determining the voltage value of the corresponding battery cell according to the acquired voltage signal of the cross-over capacitor.
Further, the control method further comprises the following steps:
and (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
Further, after the balancing control is performed on the to-be-balanced battery cell group, the method further includes:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
Advantageous effects
According to the battery active equalization control method provided by the embodiment of the invention, the battery cells forming the battery are grouped in pairs according to the voltage value, and each battery cell is controlled to be respectively connected with the same bridging capacitor based on the sequence of the voltage difference in the groups from large to small, so that the equalization control of two battery cells in each battery cell group is realized through the charge and discharge of the bridging capacitor.
Compared with a passive equalization mode, the method reduces more energy loss, and the total capacity of the battery cell is basically kept unchanged; the method realizes balanced control by controlling the connection between different battery cells and the same bridging capacitor, thereby reducing the complexity of hardware realization; meanwhile, each cell group is balanced according to the magnitude of the intra-group voltage difference, so that the priority balanced control of the cell group with the largest intra-group voltage difference is realized, and the high capacity loss caused by the largest inter-cell difference is eliminated first, so that the pertinence of the cell balanced control is stronger and the operation is simpler.
Drawings
Fig. 1 is a flowchart of a method for controlling active equalization of a battery according to an embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating connection of a switch circuit of any one of the battery cells according to an embodiment of the present invention;
Fig. 3 is a schematic diagram of a battery active equalization control system according to an embodiment of the present invention;
fig. 4 is another schematic diagram of a battery active equalization control system according to an embodiment of the present invention.
Detailed Description
The objects, technical solutions and advantages of the present invention will become more apparent by the following detailed description of the present invention with reference to the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the invention. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
Referring to fig. 1, an embodiment of the present invention provides a battery active equalization control method, including:
s1: performing pairwise grouping on n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
s2: based on the sequence of the voltage difference in the groups from large to small, each cell is controlled to be connected with the same bridging capacitor respectively, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and balanced control of two cells in each cell group is realized.
The execution body of the embodiment of the application can be active equalization control equipment.
In some embodiments, the active equalization control device may be implemented as an electronic device that includes a memory and a processor. The memory may store a program or instructions for executing the battery active equalization control method, and the processor may execute the program or instructions to implement the battery active equalization control. The processor may include a CPU (Central Processing Unit ).
In other embodiments, the active equalization control device may be implemented using application specific integrated circuit (Application Specific Integrated Circuit, ASIC) chips. The integrated circuit chip may include, but is not limited to: a Field programmable gate array (Field-Programmable Gate Array, FPGA), a programmable array logic device (Programmable Array Logic, PAL), a generic array logic device (General Array Logic, GAL), a complex programmable logic device (Complex Programmable Logic Device, CPLD), etc.
The active equalization control equipment can acquire the respective voltages of n electric cores in the battery, sequences the voltages of the n electric cores based on a preconfigured grouping logic, and groups the n electric cores connected in series in the battery in pairs according to the voltage value. The active equalization control equipment can set an identification mark for each cell and record the corresponding relation between the identification mark and the voltage value of the cell. After grouping is completed, the identification marks of the cells in the same cell group can be correspondingly recorded, and the pressure difference of the two cells in the same cell group can be correspondingly recorded and used as the pressure difference in the group for subsequent use.
And an electronic switch is connected between each cell and the bridging capacitor in advance, and can be closed or opened under the control of the active equalization control equipment, so that the cell and the bridging capacitor are in a connection state or an disconnection state. The identification mark of each battery core and the corresponding mark of the electronic switch can be correspondingly recorded. After n/2 cell groups are determined, the active equalization control device can control each cell group to be connected with the same bridging capacitor respectively by sending control signals to an electronic switch between the cell and the bridging capacitor based on the sequence of the difference from large to small in the groups. For example, the active equalization control device may determine the cell group with the greatest voltage differential and the identification of each of the two cells within the cell group. The active equalization control device may determine an electronic switch corresponding to the identification of the cells within the cell group and send a control signal to the electronic switch.
The bridge capacitor in the embodiment of the invention refers to a capacitor unit connected in parallel to two ends of different battery cells through switching of a switching circuit such as a transistor and a relay, wherein the capacitor unit can only contain one capacitor, can also contain two or more capacitors connected in series, can be specifically selected according to the battery cell electric quantity, the capacitor capacity and the like, and preferably contains a single capacitor;
According to the battery active equalization control method provided by the embodiment of the invention, the battery cells forming the battery are grouped in pairs according to the voltage value, and each battery cell is controlled to be respectively connected with the same bridging capacitor based on the sequence of the voltage difference in the groups from large to small, so that the equalization control of two battery cells in each battery cell group is realized through the charge and discharge of the bridging capacitor.
Compared with a passive equalization mode, the method reduces more energy loss, and the total capacity of the battery cell is basically kept unchanged; the method realizes balanced control by controlling the connection between different battery cells and the same bridging capacitor, thereby reducing the complexity of hardware realization; meanwhile, each cell group is balanced according to the magnitude of the intra-group voltage difference, so that the priority balanced control of the cell group with the largest intra-group voltage difference is realized, and the high capacity loss caused by the largest inter-cell difference is eliminated first, so that the pertinence of the cell balanced control is stronger and the operation is simpler.
Specifically, the grouping of n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups includes:
the following operations are repeatedly performed until no remaining cells exist in the battery:
Judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
The cell grouping is carried out based on the principle of maximum group internal pressure difference, so that the cell group with large group internal pressure difference can be balanced and controlled more pertinently, and the electric quantity balance of n cells on the whole can be realized.
Specifically, any one of the n electric cores is connected with a switch circuit; the method for controlling the balance control of the two cells in each cell group comprises the steps of controlling each cell group to be connected with the same bridging capacitor based on the sequence of the large-to-small voltage difference in the group, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and realizing the balance control of the two cells in each cell group, and the method comprises the following steps:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
After the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
after discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
In the embodiment of the invention, the switch control signals such as the first switch control signal, the second switch control signal, the third switch control signal and the like refer to electric signals for controlling the on-off of the switch circuit, such as level signals and the like;
in the embodiment of the invention, each cell group comprises two cells, the voltage difference in the cell groups refers to the difference value of the voltage values of the two cells in the same group, and the difference value can be data pre-stored in a controller, can be obtained by real-time detection and calculation through a detection circuit, and can be provided by a third party;
Through the control, the cells with larger voltage and smaller voltage in the cell group to be balanced can be sequentially connected with the same bridging capacitor, so that the process that the cells with larger voltage charge the bridging capacitor and the bridging capacitor discharge the cells with smaller voltage in the same group is realized, and the characteristics of the two cells in the cell group to be balanced tend to be consistent, so that the balance is realized.
Further, the connection between the cell with larger voltage and the bridging capacitor is disconnected; and/or
Disconnecting the cell with smaller voltage from the crossover capacitor, and then further comprising:
sending a detection switch control signal to a switch circuit between a detection circuit and the bridging capacitor so as to enable the voltage of the bridging capacitor to be connected into the detection circuit;
and acquiring the voltage signal of the cross-over capacitor sent by the detection circuit and determining the voltage value of the corresponding battery cell according to the acquired voltage signal of the cross-over capacitor.
Further, the control method further comprises the following steps:
and (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
In an optional embodiment, after performing equalization control on the to-be-equalized cell group, the method further includes:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
If yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
The method can further ensure that the performance of two battery cells in the battery cell group with larger group internal pressure difference is consistent after balanced control.
In another alternative embodiment, the n/2 cell groups are sequentially determined as the cell groups to be balanced according to the order of the pressure difference in the groups from large to small, including:
judging whether the group internal pressure difference of each cell group is within an equilibrium threshold value;
arranging the cell groups with the intra-group differential pressure not within the balance threshold according to the sequence from large to small of the intra-group differential pressure;
and sequentially determining the arranged battery cell groups as battery cell groups to be balanced so as to perform balance control.
The method omits the balanced control of the battery cell group with better consistency, and further improves the balanced efficiency.
Another embodiment of the present invention provides a battery active equalization control device, including:
the grouping unit is used for grouping n cells connected in series in the battery in pairs according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
and the control unit is used for controlling each cell to be connected with the same bridging capacitor respectively based on the sequence of the large-voltage difference in the groups, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, thereby realizing balanced control of two cells in each cell group.
Specifically, the grouping unit is configured to:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
Specifically, any one of the n electric cores is connected with a switch circuit, and the control unit is used for:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
after the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
After discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor.
Further, the control unit is further configured to:
transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so as to enable the jumper capacitor to be connected into the detection circuit;
the grouping unit is further configured to obtain the voltage signal of the cross-over capacitor sent by the detection circuit, and determine a voltage value of the corresponding battery cell according to the obtained voltage signal of the cross-over capacitor.
Further, the grouping unit is configured to:
and (3) repeating the step S1 according to the determined voltage value of each corresponding battery cell.
Further, the control unit is further configured to:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
The embodiments of the apparatus of the present invention are in one-to-one correspondence with the embodiments of the method, and are used for executing the method, and specific description and effects refer to the embodiments of the method, and are not repeated herein.
Referring to fig. 2, a third embodiment of the present invention provides a battery active equalization control system, comprising:
an active equalization control device 20 provided by the device embodiments described above for performing the control method described in any of the method embodiments described above;
a crossover capacitor 10 for connecting or disconnecting with each cell group through a switching circuit 30;
and the switching circuit 30 is used for receiving the switch control signal sent by the active equalization control device and connecting the corresponding battery cell group with the bridging capacitor according to the switch control signal.
In the embodiment of the invention, the switching circuit can be a switching circuit of a triode, a relay or the like, and the invention is not limited.
In an alternative embodiment, the switching circuit 30 includes n switch circuits corresponding to n cells one by one;
optionally, for any one of the electric cores, if the electric core is the first electric core, one end of the first switch module of the electric core is connected with the positive electrode of the electric core, and the other end is connected with one end of the bridging capacitor; the negative electrode of the battery core is grounded, the other end of the bridging capacitor is grounded, and the other end of the bridging capacitor can be grounded through control of a grounding switch; and the control end of the first switch module is used for receiving a switch control signal sent by the active equalization control device and controlling the connection or disconnection of the battery cell and the bridging capacitor.
Optionally, if the battery core is a non-first battery core, the switching circuit of any battery core is composed of a first switching module of the battery core and a second switching module of a previous battery core adjacent to the battery core; wherein the first and second switch modules are connected in a manner as shown in fig. 2.
Fig. 2 illustrates any adjacent combination in which any cell 201 is connected in series with a previous cell 200, as shown in fig. 2. One end P13 of the first switch module 301 is connected to the positive electrode of the battery cell 201, the other end P12 of the first switch module 301 is used to connect to one end of the cross-over capacitor, and one end P23 of the second switch module 302 is connected to the previous battery cell 200. The other end P22 of the second switch module 302 is used for connecting with the other end of the crossover capacitor. As a first cell, the positive electrode of the cell 200 is connected to the lower end of the crossover capacitor through the second switch module 302, the negative electrode of the cell 200 is grounded, and the upper end of the crossover capacitor is controlled to be grounded through a switch (not shown in fig. 2) in the detection switch module.
The control terminal P11 of the first switch module 301 and the control terminal P21 of the second switch module 302 are respectively connected to the output terminal of the active equalization control device 20. The first switch module 301 and the second switch module 302 are configured to be turned on or turned off under the control of a switch control signal sent by the active equalization control device, so that the cell 201 is turned on or turned off with the crossover capacitor.
Therefore, the active equalization control device sends control signals to the control ends of the first switch module and the second switch module, so that switching connection of different electric cores is realized, and the complexity of active equalization is reduced. Optionally, one end of the switch modules corresponding to all odd-numbered battery cells (such as the first switch module 302 corresponding to the 1 st battery cell and the switch module 303 corresponding to the third battery cell in fig. 2) is connected with one end (such as the lower end shown in fig. 2) of the bridging capacitor in a switchable manner, and one end of the switch module corresponding to all even-numbered battery cells (such as the second switch module 301 corresponding to the second battery cell and the switch module 304 corresponding to the fourth battery cell in fig. 2) is connected with the other end (such as the upper end shown in fig. 2) of the bridging capacitor in a switchable manner. Wherein, the odd number section is located at the odd number positions such as 1 st, 3 rd, 5 th, 7 th, etc. according to the spatial position arrangement sequence of the electric cores in the battery, and the even number section is located at the even number positions such as 2 nd, 4 th, 6 th, 8 th, etc.
Optionally, the cross-over capacitor 10 comprises a capacitor connected in parallel with a plurality of first resistors; and two ends of the capacitor are connected with the output ends of the two switch modules which are combined in any odd-even mode through resistors. The first and second switch modules continue to be exemplified. One end of the capacitor is connected with the output end of the first switch module through at least one first resistor, and the other end of the capacitor is connected with the output end of the second switch module through at least one first resistor. The at least one first resistor is used for protecting the capacitor during charging and discharging so as to reduce the service life loss of the capacitor.
Referring to fig. 2 to 4, the following is an embodiment of the present invention:
the bridge capacitor as shown in fig. 4 comprises a capacitor C1, a resistor r25, a resistor r23, a resistor r24 and a resistor r26, wherein the resistor r25, the resistor r23, the resistor r24 and the resistor r26 are sequentially connected in series, the capacitor C1 is connected with the resistor r23 and the resistor r24 in parallel, the resistor r26 is used for being connected with the output end of the first switch module, and the resistor r25 is used for being connected with the output end of the second switch module.
As shown in fig. 3, the 1 st cell in the battery is located in an odd number section, the first switch module corresponding to the 1 st cell BAT-1 includes an NPN type triode q1, a PNP type triode q2, a PNP type triode q3, a resistor r1, a resistor r2, a resistor r3 and a resistor r4, the second switch module corresponding to the 2 nd cell BAT-2 includes an NPN type triode q4, a PNP type triode q5, a PNP type triode q6, a resistor r5, a resistor r6, a resistor r7 and a resistor r8, taking the first switch module corresponding to the 1 st cell BAT-1 as an example, the collector of the NPN type triode q1 is connected with the base of the PNP type triode q3 through the resistor r2, is connected with the base of the PNP type triode q2 through the resistor r4, is also connected with the excitation pole of the PNP type triode q2 and the excitation pole of the PNP type triode q3 respectively through the resistor r3, the collector of the PNP triode q2 is connected with the positive electrode of the No. 1 cell batt-1, the collector of the PNP triode q3 is electrically connected with the end where the resistor r26 is located in the bridging capacitor, the base of the NPN triode q1 is connected with the first output end of the active equalization control device through the resistor r17 and is used for receiving a switch control signal DEC_CTR sent by the active equalization control device, meanwhile, the base of the NPN triode q1 is grounded through the resistor r18, and the emitter of the NPN triode q1 is connected with the second output end of the active equalization control device through the resistor r1 and is used for receiving the switch control signal BAT1_CTR sent by the active equalization control device. When the switch control signal DEC_CTR and the switch control signal BAT1_CTR are used for controlling the switch module corresponding to the No. 1 cell batt-1 together. For example, when the switch control signal dec_ctr is a high level signal and the switch control signal BAT1_ctr is a low level signal, the NPN transistor q1 is turned on, and the emitter of the PNP transistor q2 and the PNP transistor q3 are also turned on; the voltage of the No. 1 cell batt-1 is transmitted to the cross-over capacitor V_ODD through the excitation pole of the PNP triode q2 and the PNP triode q 3. Other switch modules are connected in the same or similar manner.
Further, the system further comprises a detection switch circuit and a detection circuit, wherein the detection switch circuit is used for receiving a detection switch control signal sent by the active equalization control device so as to connect or disconnect the detection circuit with the bridging capacitor 10;
the detection switch circuit includes two detection switch modules, where the two detection switch modules are connected to two ends of the bridge capacitor 10 in a one-to-one correspondence manner, and are used to make the bridge capacitor 10 access the detection circuit according to a detection switch control signal, specifically, the detection switch module connects one end of the corresponding bridge capacitor to ground, and voltage enters the detection circuit through the other end of the corresponding bridge capacitor, in a specific embodiment:
as shown in fig. 4, the detection switching module connected to the upper end of the bridge capacitor (i.e., between the resistor r25 and the resistor r 23) includes a resistor r21, an NPN-type triode q15, a PNP-type triode q13, and a resistor r19, the detection switching module connected to the lower end of the bridge capacitor (i.e., between the resistor r26 and the resistor r 24) includes a resistor r22, an NPN-type triode q16, a PNP-type triode q14, and a resistor r20, where, taking the detection switching module connected to the upper end of the bridge capacitor as an example, the emitter of the NPN-type triode q15 is grounded, the base of the NPN-type triode q15 is connected to the collector of the PNP-type triode q13 through the resistor r21, the collector of the NPN-type triode q15 is connected to the upper end of the bridge capacitor, and the base and the emitter of the PNP-type triode q13 are connected to the output end of the active equalization control device, respectively, and the base is used for receiving the detection switch control signal odd_vbat; the connection mode of all the components in the detection switching module connected with the lower end of the bridging capacitor is similar to that of all the components in the detection switching module, except that the base electrode of the PNP triode q14 is used for receiving a detection switch control signal EVEN_ON, and the collector electrode of the NPN triode q16 is connected with the lower end of the bridging capacitor.
As shown in fig. 4, the detection circuit includes an operational amplifier, a resistor r27, a resistor r28 and a resistor r29, wherein the positive input end of the budget amplifier is connected between the resistor r23 and the resistor r24 and is grounded through the resistor r27, the negative input end of the operational amplifier is grounded through the resistor r28 and is connected with the output end of the operational amplifier through the resistor r29, and the output end of the operational amplifier is connected with the input end of the active equalization control device for transmitting the voltage signal vbat_ad.
Based on the above system, when the cell voltage is detected, the active equalization control device (hereinafter referred to as a controller) firstly sets the level of the switch control signal dec_ctr high, then sets the level of the switch control signal batn_ctr (i.e. the switch control signal of the switch module corresponding to the positive electrode of the nth cell) low, for example sets the level of the switch control signal BAT1_ctr low, so that the corresponding NPN transistor q1 is turned on, the base of the PNP transistor q2 and the base of the PNP transistor q3 have negative currents flowing through, the two PNP transistors are turned on, and the voltage VBAT1 of the No. 1 cell BAT-1 is transferred to the bridging capacitor in the form of the network signal v_odd through the two PNP transistors. When the level of the switch control signal BAT2_CTR is set low, the corresponding NPN triode q4 is conducted, negative currents flow through the base electrode of the PNP triode q5 and the base electrode of the PNP triode q6, the two PNP triodes are conducted, and the voltage VBAT2 of the No. 2 cell batt-2 is transmitted to the bridging capacitor in the form of a network signal V_EVEN through the two PNP triodes. Here, assuming that the nth battery cell is ODD, the positive electrode corresponds to the network signal v_odd, the negative electrode corresponds to the network signal v_even, and detecting the voltage of the battery cell is equivalent to detecting the voltage difference between the network signal v_odd and the network signal v_even. The capacitor C1 is charged by the cell voltage through the resistors r25 and r26, and after the capacitor C1 is full, the control switch control signal BATn_CTR and the switch control signal BATn-1_CTR (i.e. the control signal of the switch module corresponding to the negative electrode of the nth cell) are high, so that the corresponding network signal V_ODD and the network signal V_EVEN are disconnected electrically from the cell. At this time, the detection switch control signal dec_bat is set high, the detection switch control signal odd_on is set low, the PNP transistor q13 is turned ON, and meanwhile, the PN junction of the NPN transistor q15 is turned ON in forward biased saturation, which is equivalent to grounding one end of the capacitor C1, and the voltage of the capacitor C1 enters the detection circuit after being divided by the resistor r27 and is output to the controller, thereby completing the cell voltage detection function. Similarly, if the nth battery cell is EVEN, the positive electrode corresponds to the network signal v_even, the negative electrode corresponds to the network signal v_odd, and detecting the voltage of the battery cell is equivalent to detecting the voltage difference between the network signal v_even and the network signal v_odd. The voltage of the battery cell charges the capacitor C1 through the resistors r25 and r26, and after the capacitor C1 is full, the control switch control signal BATn_CTR and the control switch control signal BATn-1_CTR are high, so that the network signal V_ODD and the network signal V_EVEN are electrically disconnected from the battery cell. At this time, the detection switch control signal dec_bat is set high, the detection switch control signal even_on is set low, the PNP transistor q14 is turned ON, and meanwhile, the PN junction of the NPN transistor q16 is turned ON in forward biased saturation, which is equivalent to grounding one end of the capacitor C1, and the voltage of the capacitor C1 enters the detection circuit after being divided by the resistor r27 and is output to the controller, thereby completing the function of detecting the voltage of the battery cell. By the above operation, it is possible to switch between different cells, while the capacitor actually connected across the cells is only capacitor C1. Because the cell voltages have differences, when the cell voltages are connected into the bridging capacitor, the bridging capacitor C1 can be charged or discharged by the different cell voltages, so that energy can be transferred among the cells through the capacitor C1, and the balance function is realized.
The specific control strategy is that firstly, voltage values of all the battery cells are respectively Vb1, vb2 … … Vbn-1 and Vbn which are acquired by a voltage detection circuit. And then sequencing the voltage values of the battery cells from small to large to obtain sequencing values corresponding to the battery cells, for example, mb1 < Mb2 < … … < Mbn-1 < Mbn. The maximum voltage difference between the cells can be found as dvmax=mbn-Mb 1, the next largest voltage difference as dVmax 2=mbn-1-Mb 2, followed in turn by dVmax (n/2) =mb (n/2) -Mb ((n-1)/2).
After the data are obtained, when the data are acquired next time, the controller adjusts the sequence of the battery core access circuits, firstly, the battery core corresponding to Mbn is accessed, the voltage value is recorded, and the voltage of the capacitor C1 is charged to Mbn; then, the corresponding battery cell of Mb1 is accessed, and the voltage value is recorded, and due to the voltage difference, a part of the charge of the capacitor C1 is transferred into the corresponding battery cell of Mb 1. Then, connecting a battery cell corresponding to Mbn-1, recording a voltage value, and charging the voltage of the capacitor C1 to Mbn-1; and then the corresponding battery cell of Mb2 is accessed, the voltage value is recorded, and due to the voltage difference, part of the charge of the capacitor C1 is transferred into the corresponding battery cell of Mb 2.
Two cells are illustrated as A, B. Assuming that the cell voltage VA has been obtained <VB, when the next voltage is sampled, the controller firstly switches the switching-on core B to charge the capacitor C1, and the charging voltage is VB; then the control switch-on core A is switched, the capacitor C1 discharges to the core A because the voltage of the capacitor C1 is higher than that of the core A, the energy is transferred from the core B to the core A, and the energy transferred each time is DE=1/2×C1 (VB 2 –VA 2 ) By switching between the two cells multiple times, the two cells are gradually balanced. And similarly, sequentially accessing a pair of battery cells with the next highest voltage difference until all the battery cells are polled for one time.
After the above operation is completed, the controller reorders the sequence and repeats the above steps, so that energy is continuously transferred from the high-voltage battery cells to the low-voltage battery cells, and equalization among the battery cells is realized. In addition, when the voltage difference between the battery cores is within the balance threshold value, repeating the control; when the voltage difference between the battery cells exceeds the equilibrium threshold, the pair of battery cells with the highest voltage difference can be repeated for a plurality of times in a short time.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the application are to be included in the scope of the claims of the present application.

Claims (4)

1. The battery active equalization control method is characterized by comprising the following steps of:
s1: performing pairwise grouping on n cells connected in series in the battery according to the voltage value to obtain n/2 cell groups, wherein n is an even number;
s2: based on the sequence of the voltage difference in the groups from large to small, controlling each cell to be connected with the same bridging capacitor respectively, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, thereby realizing balanced control of two cells in each cell group;
any one of the n electric cores is connected with a switch circuit; the method for controlling the balance control of the two cells in each cell group comprises the steps of controlling each cell group to be connected with the same bridging capacitor based on the sequence of the large-to-small voltage difference in the group, so that the cell with larger voltage in any cell group charges the bridging capacitor, and the bridging capacitor discharges the cell with smaller voltage in any cell group, and realizing the balance control of the two cells in each cell group, and the method comprises the following steps:
sequentially determining the n/2 cell groups as cell groups to be balanced according to the sequence of the large-to-small pressure differences in the groups, and performing the following balance control on the cell groups to be balanced:
Sending a first switch control signal to a switch circuit of a cell with a larger voltage in the cell group to be balanced so that the voltage of the cell with the larger voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the cell with the larger voltage charges the bridging capacitor;
after the charging is completed, a second switch control signal is sent to a switch circuit of a cell with larger voltage in the cell group to be balanced so as to disconnect the cell with larger voltage from the bridging capacitor;
transmitting a third switch control signal to a switch circuit of a cell with smaller voltage in the cell group to be balanced so that the voltage of the cell with smaller voltage in the cell group to be balanced is connected to two ends of the bridging capacitor, and the bridging capacitor discharges to the cell with smaller voltage;
after discharging, sending a fourth switching control signal to a switching circuit of a cell with smaller voltage in the cell group to be balanced so as to disconnect the cell with smaller voltage from the bridging capacitor;
disconnecting the cell with larger voltage from the cross-over capacitor; and/or
Disconnecting the cell with smaller voltage from the crossover capacitor, and then further comprising:
Transmitting a detection switch control signal to a switch circuit between a detection circuit and the jumper capacitor so as to enable the jumper capacitor to be connected into the detection circuit;
acquiring a voltage signal of the cross-over capacitor sent by the detection circuit and determining a voltage value of a corresponding battery cell according to the acquired voltage signal of the cross-over capacitor;
the battery active equalization control system based on the control method comprises the following steps:
the active equalization control device is used for executing the control method;
the bridging capacitor is used for connecting or disconnecting with each cell group through the switching circuit;
the switching circuit is used for receiving a switch control signal sent by the active equalization control device and connecting a corresponding battery cell group with the bridging capacitor according to the switch control signal;
the switching circuit comprises n switch circuits which are in one-to-one correspondence with the n battery cores;
for any battery core, if the battery core is the first battery core, one end of a first switch module of the battery core is connected with the positive electrode of the battery core, and the other end of the first switch module of the battery core is connected with one end of the bridging capacitor; the negative electrode of the battery cell is grounded, and the other end of the bridging capacitor is grounded; the control end of the first switch module is used for receiving a switch control signal sent by the active equalization control device and controlling the connection or disconnection of the battery cell and the bridging capacitor;
For any one of the electric cores, if the electric core is a non-initial electric core, the switch circuit of the any electric core is composed of a first switch module of the electric core and a second switch module of the previous electric core adjacent to the electric core; the first switch module and the second switch module in the switch circuit of any cell are connected in the following manner:
one end of the first switch module is connected with the positive electrode of the battery cell, and the other end of the first switch module is connected with one end of the bridging capacitor; one end of the second switch module is connected with the negative electrode of the battery cell, and the other end of the second switch module is connected with the other end of the bridging capacitor;
the control end of the first switch module and the control end of the second switch module are respectively connected with the output end of the active equalization control device; the first switch module and the second switch module are used for being closed under a switch control signal sent by the active equalization control device so as to enable the battery cell to be connected with the bridging capacitor;
the crossover capacitance comprises a capacitor connected in parallel with a plurality of first resistors; one end of the capacitor is connected with the output end of the first switch module through at least one first resistor, and the other end of the capacitor is connected with the output end of the second switch module through at least one first resistor;
The first switch module comprises an NPN triode, a first PNP triode, a second resistor, a third resistor and a fourth resistor, wherein the base electrode and the emitter electrode of the NPN triode are respectively connected with the output end of the active equalization control device, the collector electrode of the NPN triode is connected with the base electrode of the first PNP triode through the second resistor, is connected with the base electrode of the second PNP triode through the third resistor and is respectively connected with the exciting electrode of the first PNP triode and the exciting electrode of the second PNP triode through the fourth resistor, the collector electrode of the first PNP triode is connected with the corresponding electric core, and the collector electrode of the second PNP triode is connected with the bridging capacitor; the second switch module is consistent with the first switch module in structure;
the control system also comprises a detection switch circuit and a detection circuit;
the detection switch circuit is used for receiving a detection switch control signal sent by the active equalization control device so as to connect or disconnect the detection circuit and the bridging capacitor;
the detection circuit is used for sending the voltage signal of the cross-over capacitor to the active equalization control device;
The detection switching circuit comprises two detection switching modules, the two detection switching modules are connected with two ends of the bridging capacitor in a one-to-one correspondence manner, the detection switching modules comprise a fifth resistor, an NPN triode, a PNP triode and a sixth resistor, wherein an emitter of the NPN triode is grounded, a base of the NPN triode is connected with a collector of the PNP triode through the fifth resistor, a collector of the NPN triode is connected with one end of the bridging capacitor, a collector of the PNP triode is grounded through the sixth resistor, and a base and an emitter of the PNP triode are respectively connected with an output end of the active equalization control device;
the detection circuit comprises an operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor, wherein a first input end of the operational amplifier is connected between the two first resistors connected in parallel with the capacitor and is grounded through the seventh resistor;
the second input end of the operational amplifier is grounded through an eighth resistor and is connected with the output end of the operational amplifier through a ninth resistor;
and the output end of the operational amplifier is connected with the input end of the active equalization control device.
2. The control method according to claim 1, wherein the grouping n cells connected in series in the battery in pairs according to the voltage value, to obtain n/2 cell groups, includes:
the following operations are repeatedly performed until no remaining cells exist in the battery:
judging whether residual battery cores exist in the battery or not;
and determining two cells with the largest voltage value and the smallest voltage value in the remaining cells as a group.
3. The control method according to claim 1, further comprising, after the balancing control is performed on the cell group to be balanced:
judging whether the group internal pressure difference after the cell group to be balanced is subjected to balanced control meets an equalization threshold value or not;
if yes, performing balanced control on the next cell group;
and if not, repeating the balance control on the cell group to be balanced until the controlled intra-group pressure difference meets the balance threshold.
4. A battery active equalization control system, comprising:
active equalization control means for performing the control method of any one of claims 1 to 3;
the bridging capacitor is used for connecting or disconnecting with each cell group through the switching circuit;
the switching circuit is used for receiving a switch control signal sent by the active equalization control device and connecting a corresponding battery cell group with the bridging capacitor according to the switch control signal;
The switching circuit comprises n switch circuits which are in one-to-one correspondence with the n battery cores;
for any battery core, if the battery core is the first battery core, one end of a first switch module of the battery core is connected with the positive electrode of the battery core, and the other end of the first switch module of the battery core is connected with one end of the bridging capacitor; the negative electrode of the battery cell is grounded, and the other end of the bridging capacitor is grounded; the control end of the first switch module is used for receiving a switch control signal sent by the active equalization control device and controlling the connection or disconnection of the battery cell and the bridging capacitor;
for any one of the electric cores, if the electric core is a non-initial electric core, the switch circuit of the any electric core is composed of a first switch module of the electric core and a second switch module of the previous electric core adjacent to the electric core; the first switch module and the second switch module in the switch circuit of any cell are connected in the following manner:
one end of the first switch module is connected with the positive electrode of the battery cell, and the other end of the first switch module is connected with one end of the bridging capacitor; one end of the second switch module is connected with the negative electrode of the battery cell, and the other end of the second switch module is connected with the other end of the bridging capacitor;
The control end of the first switch module and the control end of the second switch module are respectively connected with the output end of the active equalization control device; the first switch module and the second switch module are used for being closed under a switch control signal sent by the active equalization control device so as to enable the battery cell to be connected with the bridging capacitor;
the crossover capacitance comprises a capacitor connected in parallel with a plurality of first resistors; one end of the capacitor is connected with the output end of the first switch module through at least one first resistor, and the other end of the capacitor is connected with the output end of the second switch module through at least one first resistor;
the first switch module comprises an NPN triode, a first PNP triode, a second resistor, a third resistor and a fourth resistor, wherein the base electrode and the emitter electrode of the NPN triode are respectively connected with the output end of the active equalization control device, the collector electrode of the NPN triode is connected with the base electrode of the first PNP triode through the second resistor, is connected with the base electrode of the second PNP triode through the third resistor and is respectively connected with the exciting electrode of the first PNP triode and the exciting electrode of the second PNP triode through the fourth resistor, the collector electrode of the first PNP triode is connected with the corresponding electric core, and the collector electrode of the second PNP triode is connected with the bridging capacitor; the second switch module is consistent with the first switch module in structure;
The control system also comprises a detection switch circuit and a detection circuit;
the detection switch circuit is used for receiving a detection switch control signal sent by the active equalization control device so as to connect or disconnect the detection circuit and the bridging capacitor;
the detection circuit is used for sending the voltage signal of the cross-over capacitor to the active equalization control device;
the detection switching circuit comprises two detection switching modules, the two detection switching modules are connected with two ends of the bridging capacitor in a one-to-one correspondence manner, the detection switching modules comprise a fifth resistor, an NPN triode, a PNP triode and a sixth resistor, wherein an emitter of the NPN triode is grounded, a base of the NPN triode is connected with a collector of the PNP triode through the fifth resistor, a collector of the NPN triode is connected with one end of the bridging capacitor, a collector of the PNP triode is grounded through the sixth resistor, and a base and an emitter of the PNP triode are respectively connected with an output end of the active equalization control device;
the detection circuit comprises an operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor, wherein a first input end of the operational amplifier is connected between the two first resistors connected in parallel with the capacitor and is grounded through the seventh resistor;
The second input end of the operational amplifier is grounded through an eighth resistor and is connected with the output end of the operational amplifier through a ninth resistor;
and the output end of the operational amplifier is connected with the input end of the active equalization control device.
CN202310562858.6A 2023-05-18 2023-05-18 Battery active equalization control method, device and system Active CN116315199B (en)

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