CN116760146A - Active equalization circuit and method of battery pack - Google Patents

Active equalization circuit and method of battery pack Download PDF

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Publication number
CN116760146A
CN116760146A CN202310956788.2A CN202310956788A CN116760146A CN 116760146 A CN116760146 A CN 116760146A CN 202310956788 A CN202310956788 A CN 202310956788A CN 116760146 A CN116760146 A CN 116760146A
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CN
China
Prior art keywords
bidirectional
module
battery
pack
voltage
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Pending
Application number
CN202310956788.2A
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Chinese (zh)
Inventor
李友刚
曾卓
何江
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Sichuan Jietong Ruilian Technology Co ltd
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Sichuan Jietong Ruilian Technology Co ltd
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Priority to CN202310956788.2A priority Critical patent/CN116760146A/en
Publication of CN116760146A publication Critical patent/CN116760146A/en
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Classifications

    • 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
    • H02J7/0013—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
    • 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
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • 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
    • H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention provides an active equalization circuit and method of a battery PACK, wherein the active equalization circuit comprises N PACK groups connected in parallel, the PACK groups comprise X bidirectional DC/DC modules and X battery PACKs, and the battery PACKs are arranged in one-to-one correspondence with the bidirectional DC/DC modules; the power supply comprises a power supply positive wire, a power supply negative wire and a power supply, wherein a first main switch is arranged on the power supply positive wire, a second main switch is arranged on the power supply negative wire, the first main switch and the second main switch are normally open, and the PACK group is connected to the power supply positive wire and the power supply negative wire; the power supply is electrically connected with the load; the bidirectional DC/DC module is provided with a first high-voltage port, a second high-voltage port, a first low-voltage port and a second low-voltage port, and the first high-voltage port and the second high-voltage port are respectively connected with a positive power line and a negative power line; the battery pack comprises M batteries connected in series and M switch groups connected in parallel, and the switch groups are normally open; the switch group is arranged corresponding to the battery.

Description

Active equalization circuit and method of battery pack
Technical Field
The invention relates to the technical field of battery control, in particular to an active equalization circuit and method of a battery pack.
Background
In order to ensure the uniformity of the cell capacity balance among the cell groups, and avoid the shortening of the service life of the cell groups due to the energy unbalance of the cell batteries among the cell groups, the cell capacity balance among the cell groups becomes an essential important function in various product designs, and the balancing modes can be divided into an active balancing mode and a passive balancing mode;
the passive equalization is to equalize the monomer capacity among the battery packs, so that the self-circuit consumes larger power consumption, and the efficiency of the whole system is reduced due to heat loss generated by resistance energy consumption in the mode of simple structure and low cost;
the active equalization mode is equalization realized by energy transfer, each string of battery voltage data is detected, and the battery energy with high voltage is transferred to the battery with low voltage, so that lossless energy transfer is almost realized, but the technology is complex, the cost is high, and the safety is also to be improved.
Disclosure of Invention
The invention aims to provide an active equalization circuit and an active equalization method for a battery pack, and aims to solve the technical problem of reducing the complexity of the active equalization circuit.
The invention is realized by the following technical scheme:
a first aspect provides an active equalization circuit for a battery pack, comprising:
the system comprises N PACK groups connected in parallel, wherein the PACK groups comprise X bidirectional DC/DC modules and X battery groups, and the battery groups are arranged in one-to-one correspondence with the bidirectional DC/DC modules;
the power supply comprises a power supply positive wire, a power supply negative wire and a power supply, wherein a first main switch is arranged on the power supply positive wire, a second main switch is arranged on the power supply negative wire, the first main switch and the second main switch are normally open, and the PACK group is connected to the power supply positive wire and the power supply negative wire;
and a load, wherein the power supply is electrically connected with the load.
The first main switch and the second main switch are used for connecting the PACK to a power supply, the replaceable bidirectional DC/DC module is utilized, the replaceable performance is strong, the complexity of an active equalization circuit can be reduced, the safety of the active equalization circuit is improved, the bidirectional DC/DC module controls the power voltage increasing and decreasing direction, and if the enabling end of the bidirectional DC/DC module is a voltage increasing function, the battery PACK discharges; if the enabling end of the bidirectional DC/DC module is in a voltage reducing function, charging the battery pack;
the power supply is connected to a load which supplies power to the PACK when it is charged and which consumes power when it is discharged.
Further, the bidirectional DC/DC module is provided with a first high-voltage port, a second high-voltage port, a first low-voltage port and a second low-voltage port, wherein the first high-voltage port and the second high-voltage port are respectively connected with a positive power line and a negative power line;
the battery pack comprises M batteries connected in series and M switch groups connected in parallel, and the switch groups are normally open;
the switch groups are arranged in one-to-one correspondence with the batteries;
the switch group comprises a first switch and a second switch, the battery is connected with the first low-voltage port through the first switch, and the battery is connected with the second low-voltage port through the second switch.
Each switch group independently controls the on-off of the corresponding battery, so as to realize the charge and discharge functions of the battery.
A second aspect provides an active equalization method of a battery pack, the method being implemented based on the active equalization circuit described above;
the method comprises the following steps:
acquiring the voltage of each battery in all PACK groups, calculating a voltage threshold according to the voltage of each battery, and comparing the voltage of each battery with the voltage threshold respectively;
if the voltage of the battery is smaller than the voltage threshold value, generating a charging instruction for charging the battery;
if the voltage of the battery is greater than the voltage threshold, generating a discharge instruction for discharging the battery;
and controlling the on-off of the first main switch, the second main switch and a switch group connected with the battery according to the charging instruction and the discharging instruction.
When the voltage of one battery in all PACK groups is too much higher than that of other batteries, the active equalization strategy is utilized to charge the batteries simultaneously, and the batteries can also discharge simultaneously, so that the batteries or the single battery are required to absorb and charge at the moment, and when the power supply is not consumed too much, the battery is required to absorb.
Further, after the voltages of the batteries in all PACK groups are obtained, the method further comprises the following steps:
acquiring the voltage of each battery connected with the x bidirectional DC/DC module in the n-1-th PACK group and the voltage of each battery connected with the x bidirectional DC/DC module in the n-th PACK group;
comparing the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group with the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK is smaller than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is equal to the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, the circuit is in an equilibrium state.
Further, after closing the switch group connected with the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group, comparing the voltage of the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group with a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than a voltage threshold, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is smaller than the voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group.
Further, according to the discharging instruction of the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group, closing the first main switch and the second main switch, and charging the power supply by the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the nth PACK group, and charging the mth battery connected with the x bidirectional DC/DC module in the nth PACK group by the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group.
Further, according to the charging instruction of the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group, the first main switch and the second main switch are closed, and the power supply charges the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group.
Further, after closing the switch group connected with the mth battery connected with the x bidirectional DC/DC module in the nth PACK group, comparing the voltage of the mth battery connected with the x bidirectional DC/DC module in the nth PACK group with a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is larger than a voltage threshold value, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is smaller than the voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group.
Further, according to the discharging instruction of the mth battery connected with the x bidirectional DC/DC module in the nth PACK group, the first main switch and the second main switch are closed, and the mth battery connected with the x bidirectional DC/DC module in the nth PACK group charges a power supply;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group, wherein the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group charges an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group.
Further, according to the charging instruction of the mth battery connected with the x bidirectional DC/DC module in the nth PACK group, the first main switch and the second main switch are closed, and the power supply charges the mth battery connected with the x bidirectional DC/DC module in the nth PACK group.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the first main switch and the second main switch are used for connecting the PACK to a power supply, the replaceable bidirectional DC/DC module is utilized, the replaceable performance is strong, the complexity of an active equalization circuit can be reduced, the safety of the active equalization circuit is improved, the bidirectional DC/DC module controls the power voltage increasing and decreasing direction, and if the enabling end of the bidirectional DC/DC module is a voltage increasing function, the battery PACK discharges; if the enabling end of the bidirectional DC/DC module is in a voltage reducing function, charging the battery pack;
the power supply is connected to a load which supplies power to the PACK when it is charged and which consumes power when it is discharged.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are needed in the examples will be briefly described below, it being understood that the following drawings only illustrate some examples of the present invention and therefore should not be considered as limiting the scope, and that other related drawings may be obtained from these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a circuit diagram provided in example 1;
fig. 2 is a flow chart provided in example 2.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.
Example 1
Embodiment 1 provides an active equalization circuit of a battery pack, including:
the system comprises N PACK groups connected in parallel, wherein the PACK groups comprise X bidirectional DC/DC modules and X battery groups, and the battery groups are arranged in one-to-one correspondence with the bidirectional DC/DC modules;
the power supply comprises a power supply positive wire, a power supply negative wire and a power supply, wherein a first main switch is arranged on the power supply positive wire, a second main switch is arranged on the power supply negative wire, the first main switch and the second main switch are normally open, and the PACK group is connected to the power supply positive wire and the power supply negative wire;
a load (not shown in fig. 1), the power supply being electrically connected to the load.
The bidirectional DC/DC module can be an existing bidirectional DC/DC module in the market, or can be a self-developed bidirectional DC/DC module; the bidirectional DC/DC module has an enabling control end or a non-enabling control end, and the use is not affected.
The first main switch and the second main switch are used for connecting the PACK to a power supply, the replaceable bidirectional DC/DC module is utilized, the replaceable performance is strong, the complexity of an active equalization circuit can be reduced, the safety of the active equalization circuit is improved, the bidirectional DC/DC module controls the power voltage increasing and decreasing direction, and if the enabling end of the bidirectional DC/DC module is a voltage increasing function, the battery PACK discharges; if the enabling end of the bidirectional DC/DC module is in a voltage reducing function, charging the battery pack;
the power supply is connected to a load which supplies power to the PACK when it is charged and which consumes power when it is discharged.
In a specific embodiment, the bidirectional DC/DC module is provided with a first high-voltage port, a second high-voltage port, a first low-voltage port and a second low-voltage port, and the first high-voltage port and the second high-voltage port are respectively connected to a positive power line and a negative power line;
the battery pack comprises M batteries connected in series and M switch groups connected in parallel, and the switch groups are normally open;
the switch groups are arranged in one-to-one correspondence with the batteries;
the switch group includes a first switch and a second switch, the battery is connected to the first low voltage port (positive polarity) through the first switch, and the battery is connected to the second low voltage port (negative polarity) through the second switch.
In order to enable the bidirectional DC/DC module to be used across the PACKs, a first high-voltage port and a second high-voltage port of the bidirectional DC/DC module are respectively connected into a positive power line and a negative power line for connecting the PACKs;
the first low-voltage port and the second low-voltage port of the bidirectional DC/DC module are connected with the battery through the switch group, the first switch and the second switch in the switch group can adopt one or more of MOSFET, IGBT or relay and other power switches, the batteries in all PACK groups are connected with the low-voltage end power buses of the bidirectional DC/DC module, and the low-voltage end power buses are also two wires, namely a positive polarity and a negative polarity.
Each switch group independently controls the on-off of the corresponding battery, so as to realize the charge and discharge functions of the battery.
In a specific embodiment, for convenience in calculation, taking the voltage of the high-voltage end of the bidirectional DC/DC module as an integer multiple of the low-voltage end, the voltage range is a wide range, m=16 as an example, the active equalization process is explained, and the protection range of the present invention is not limited by this example:
as shown in FIG. 1, the low-voltage terminal voltage is 3.3V, the high-voltage terminal voltage is 3.3-50V, X is an integer and X is greater than or equal to 1, N is an integer and N is greater than or equal to 1, the power supply anode is 5V, the power supply anode is grounded, the power supply supplies power to the PACK group, TJn-X represents the xth bidirectional DC/DC module in the nth PACK group, bn-X-m represents the mth battery of the xth bidirectional DC/DC module in the nth PACK group, sn-X-m represents the mth switch group of the xth bidirectional DC/DC module in the nth PACK group, sn-X-m-1 represents the first switch of the mth switch group of the xth bidirectional DC/DC module in the nth PACK group, sn-X-m-2 represents the second switch of the mth switch group of the xth bidirectional DC/DC module in the nth PACK group, SK1 represents the mth total switch.
In a specific embodiment, active equalization is performed in different PACK groups;
(1) When the voltage of the battery B1-1-16 is larger than that of the battery Bn-1-16, the switch group S1-1-16 is conducted, the low end of the bidirectional DC/DC module is charged, and the high end output is effective;
(1) if SK1 and SK2 are conducted at this time, the batteries B1-1-16 are charged for the power supply, and at this time, the batteries B1-1-16 are discharged to the positive line and the negative line of the power supply, and the load connected with the power supply consumes electric energy;
(2) if the switch group Sn-1-16 is turned on at this time, the battery B1-1-16 charges the battery Bn-1-16.
(2) When the voltage of the battery B1-1-16 is smaller than that of the battery Bn-1-16, the switch group Sn-1-16 is conducted, the low end of the bidirectional DC/DC module is charged, and the high end output is effective;
(1) if SK1 and SK2 are conducted at this time, batteries Bn-1-16 charge the power supply, and at this time, batteries Bn-1-16 discharge to the positive power supply line and the negative power supply line, and the load connected with the power supply consumes electric energy;
(2) if the switch group S1-1-16 is turned on at this time, the battery Bn-1-16 charges the battery B1-1-16.
In a specific embodiment, active equalization is completed in the same battery PACK in the same PACK group, and no power supply and other PACK groups are needed to participate at this time;
for example: if the active equalization (x is more than or equal to 1) is to be performed on the batteries B1-x-14 and B1-x-16 connected with the x-th bidirectional DC/DC module in the 1 st PACK group, the switch group S1-x-14 and the switch group S1-x-16 connected with the batteries B1-x-14 and B1-x-16 are directly opened for hard equalization.
In a specific embodiment, active equalization can be completed in different battery PACKs in the same PACK group, and no power supply and other PACK groups are needed to participate at this time;
for example: if the batteries B1-1-16 and B1-x-16 in the 1 st PACK group are to be actively balanced, and the voltage of the battery B1-1-16 is greater than the voltage threshold, and the voltage of the battery B1-x-16 is less than the voltage threshold, the discharging switch of the battery B1-1-16 and the charging switch of the battery B1-x-16 are both closed, and at this time, the battery B1-1-16 charges the battery B1-x-16 until the battery B1-x-16 reaches the voltage threshold, and the switch groups S1-1-16 and S1-x-16 are not opened.
Example 2
The embodiment 2 provides an active equalization method of a battery pack, which is implemented based on the active equalization circuit;
as shown in fig. 2, the method comprises the steps of:
s10, acquiring the voltage of each battery in all PACK groups, calculating a voltage threshold according to the voltage of each battery, and comparing the voltage of each battery with the voltage threshold respectively;
s21, if the voltage of the battery is smaller than a voltage threshold value, generating a charging instruction for charging the battery;
s22, if the voltage of the battery is greater than a voltage threshold, generating a discharge instruction for discharging the battery;
and S30, controlling the on-off of the first main switch, the second main switch and the switch group connected with the battery according to the charging instruction and the discharging instruction, or controlling the on-off of the switch group connected with other batteries (other batteries comprise different batteries of the same battery group in the same PACK group, batteries of different battery groups in the same PACK group and batteries of different PACK groups).
When the voltage of one battery in all PACK groups is too much higher than that of other batteries, the active equalization strategy is utilized to charge the batteries simultaneously, and the batteries can also discharge simultaneously, so that the batteries or the single battery are required to absorb and charge at the moment, and when the power supply is not consumed too much, the battery is required to absorb.
In a specific embodiment, after the voltage of each battery in all PACK groups is obtained, the method further includes the following steps:
acquiring the voltage of each battery connected with the x bidirectional DC/DC module in the n-1-th PACK group and the voltage of each battery connected with the x bidirectional DC/DC module in the n-th PACK group;
comparing the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group with the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK is smaller than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is equal to the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, the circuit is in an equilibrium state.
In a specific embodiment, after closing a switch group connected with an mth battery connected with an x bidirectional DC/DC module in the nth-1 PACK group, comparing the voltage of the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group with a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than a voltage threshold, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is smaller than the voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group.
In a specific embodiment, according to a discharging instruction of an mth battery connected with an xth bidirectional DC/DC module in the nth-1 PACK group, closing a first main switch and a second main switch, wherein the mth battery connected with the xth bidirectional DC/DC module in the nth-1 PACK group charges a power supply;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the nth PACK group, and charging the mth battery connected with the x bidirectional DC/DC module in the nth PACK group by the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group.
In a specific embodiment, according to the charging instruction of the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group, the first main switch and the second main switch are closed, and the power supply charges the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group.
In a specific embodiment, after closing a switch group connected to an mth battery connected to an xth bidirectional DC/DC module in the nth PACK group, comparing a voltage of the mth battery connected to the xth bidirectional DC/DC module in the nth PACK group with a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is larger than a voltage threshold value, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is smaller than the voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group.
In a specific embodiment, according to a discharging instruction of an mth battery connected with an xth bidirectional DC/DC module in the nth PACK group, closing a first main switch and a second main switch, where the mth battery connected with the xth bidirectional DC/DC module in the nth PACK group charges a power supply;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group, wherein the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group charges an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group.
In a specific embodiment, according to the charging instruction of the mth battery connected to the x bidirectional DC/DC module in the nth PACK group, the first main switch and the second main switch are closed, and the power supply charges the mth battery connected to the x bidirectional DC/DC module in the nth PACK group.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (10)

1. An active equalization circuit for a battery, comprising:
the system comprises N PACK groups connected in parallel, wherein the PACK groups comprise X bidirectional DC/DC modules and X battery groups, and the battery groups are arranged in one-to-one correspondence with the bidirectional DC/DC modules;
the power supply comprises a power supply positive wire, a power supply negative wire and a power supply, wherein a first main switch is arranged on the power supply positive wire, a second main switch is arranged on the power supply negative wire, the first main switch and the second main switch are normally open, and the PACK group is connected to the power supply positive wire and the power supply negative wire;
and the power supply is electrically connected with the load.
2. The active equalization circuit of claim 1, wherein the bi-directional DC/DC module is provided with a first high voltage port, a second high voltage port, a first low voltage port, and a second low voltage port, the first high voltage port and the second high voltage port being connected to a positive power supply line and a negative power supply line, respectively;
the battery pack comprises M batteries connected in series and M switch groups connected in parallel, and the switch groups are normally open;
the switch groups are arranged in one-to-one correspondence with the batteries;
the switch group comprises a first switch and a second switch, the battery is connected with the first low-voltage port through the first switch, and the battery is connected with the second low-voltage port through the second switch.
3. A method of active equalization of a battery, characterized in that the method is implemented on the basis of an active equalization circuit according to any of claims 1-2;
the method comprises the following steps:
acquiring the voltage of each battery in all PACK groups, calculating a voltage threshold according to the voltage of each battery, and comparing the voltage of each battery with the voltage threshold respectively;
if the voltage of the battery is smaller than the voltage threshold value, generating a charging instruction for charging the battery;
if the voltage of the battery is greater than the voltage threshold, generating a discharge instruction for discharging the battery;
and controlling the on-off of the first main switch, the second main switch and the switch group connected with the battery according to the charging instruction and the discharging instruction.
4. A method of active equalization of a battery PACK as defined in claim 3, further comprising the steps of, after said obtaining voltages of each cell in all PACK groups:
acquiring the voltage of each battery connected with the x bidirectional DC/DC module in the n-1-th PACK group and the voltage of each battery connected with the x bidirectional DC/DC module in the n-th PACK group;
comparing the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group with the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is smaller than the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, closing a switch group connected with the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is equal to the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group, the circuit is in an equilibrium state.
5. The method of claim 4, wherein after closing the switch group connected to the mth battery connected to the x bidirectional DC/DC module in the nth-1 PACK group, comparing the voltage of the mth battery connected to the x bidirectional DC/DC module in the nth-1 PACK group with a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is larger than a voltage threshold, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group is smaller than a voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-1-th PACK group.
6. The method according to claim 5, wherein the first main switch and the second main switch are closed according to a discharging instruction of an mth battery connected with an xth bidirectional DC/DC module in the nth-1 PACK, and the mth battery connected with the xth bidirectional DC/DC module in the nth-1 PACK charges a power source;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the nth PACK group, wherein the mth battery connected with the x bidirectional DC/DC module in the nth-1 PACK group charges the mth battery connected with the x bidirectional DC/DC module in the nth PACK group.
7. The method according to claim 5, wherein the first main switch and the second main switch are closed according to a charging command of an mth battery connected to the x bidirectional DC/DC module in the n-1 th PACK, and the power supply charges the mth battery connected to the x bidirectional DC/DC module in the n-1 th PACK.
8. The method of claim 4, wherein after closing a switch group connected to an mth battery of the nth PACK group connected to an x bidirectional DC/DC module, comparing a voltage of the mth battery of the nth PACK group connected to the x bidirectional DC/DC module to a voltage threshold;
if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is larger than a voltage threshold value, a discharging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is generated;
and if the voltage of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group is smaller than a voltage threshold value, generating a charging instruction of the m-th battery connected with the x-th bidirectional DC/DC module in the n-th PACK group.
9. The method according to claim 8, wherein the first total switch and the second total switch are closed according to a discharging instruction of an mth battery connected to an xth bidirectional DC/DC module in the nth PACK, and the mth battery connected to the xth bidirectional DC/DC module in the nth PACK charges a power source;
or,
and closing a switch group connected with an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group, wherein the mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group charges an mth battery connected with the x bidirectional DC/DC module in the n-1 th PACK group.
10. The method of claim 8, wherein the first and second main switches are closed according to a charge command of an mth battery connected to the x bidirectional DC/DC module in the nth PACK, and the power source charges the mth battery connected to the x bidirectional DC/DC module in the nth PACK.
CN202310956788.2A 2023-08-01 2023-08-01 Active equalization circuit and method of battery pack Pending CN116760146A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117118033A (en) * 2023-10-18 2023-11-24 南京中交航信新能源科技有限公司 BMS battery cell level active equalization system and active equalization method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117118033A (en) * 2023-10-18 2023-11-24 南京中交航信新能源科技有限公司 BMS battery cell level active equalization system and active equalization method thereof
CN117118033B (en) * 2023-10-18 2024-01-23 南京中交航信新能源科技有限公司 BMS battery cell level active equalization system and active equalization method thereof

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