70results about How to "Shorten equalization time" patented technology

Providing a charge condition adjusting apparatus, which can shorten a time for equalization of each charge in unit cells, a low-voltage CPU selects each smallest unit cell in the each cell block, which has each smallest voltage between the both electrodes, from among plural unit cells structuring the cell blocks. The low-voltage CPU controls ON / OFF of a block-discharging switch to connect the both electrodes of each cell block and each block-discharging resistor for discharging the each cell block until the each voltage between the both electrodes of the selected smallest unit cell reaches the target voltage. Successively, the low-voltage CPU controls ON / OFF of a selecting switches and a cell-discharging switch to connect the both electrodes of each unit cell and each cell-discharging resistor to discharge the each unit cell until the each voltage between the both electrodes of the unit cells reaches the target voltage.

The invention discloses an energy transfer two-way balancing system based on a power inductor and a control method of the energy transfer two-way balancing system based on the power inductor. The energy transfer two-way balancing system based on the power inductor comprises a data acquisition module, a master control module, a communication module, a balancing module and a driver module, and a two-way balancing circuit topology structure which uses the power inductor as an energy transfer medium is selected. According to the general balancing thinking of the energy transfer two-way balancing system based on the power inductor and the control method of the energy transfer two-way balancing system, the data acquisition module carries out real-time detection on voltage of batteries in a battery pack and electric current of buses in the battery pack, and identifies the working state of the battery pack, inconsistency judgment is carried out through balance variables determined in advance and balance indexes determined in advance, balancing is carried out according to an established control strategy when balance conditions are met, the states of the batteries are continuously monitored, and balancing is stopped until stop conditions are met. Energy can be transferred from the battery with higher voltage to the battery with lower voltage and adjacent to the battery with the higher voltage through control over a switch of an MOSFET corresponding to the battery with the higher voltage, and the magnitude of balanced current is related to the closing time of the corresponding MOSFET. The energy transfer two-way balancing system based on the power inductor can carry out pending balancing, charging balancing and discharging balancing, achieve efficient and comprehensive balancing, and finally solve the problem that the batteries are not consistent in the process of use.

The invention discloses a composite automatic synchronous energy transfer equalization circuit and an equalization method for a series battery pack. The circuit comprises n composite two-way battery unit energy transfer equalization modules, a master control module and equalization buses, wherein the composite two-way battery unit energy transfer equalization modules are arranged according to the number of battery units in the series battery pack; n is more than or equal to 1; the composite two-way battery unit energy transfer equalization module corresponds to a battery module consisting of k battery units which are connected in series; k is more than 1; and the composite two-way battery unit energy transfer equalization module consists of a switch matrix, an equalization control module, a two-way direct current (DC)-DC module, k discharge equalization circuits and a mode control switch. The composite automatic synchronous energy transfer equalization circuit and the equalization method for the series battery pack are high in reliability, low in cost, small in volume, light in weight, functionally comprehensive and easy to manufacture and use in large scale, and can be applied in the fields of electric vehicles, rail transit, wind-driven power generation and the like by which the series battery pack and a series capacitor bank are required.

The invention discloses a battery management system and balance method with a parallel balance function. The battery management system comprises a battery pack with 24 lithium ion batteries, six single chip microcomputer-based battery monitoring modules, a main controller, six single battery gating modules, an active balance module, a communication module, a charge-discharge protection apparatus and a battery module. By virtue of the battery management system, monitoring and control for 24 batteries can be realized, and functions of monitoring the working parameters of the single batteries, and performing passive balance, active balance, parallel balance, charge-discharge overcurrent protection and upper computer communication and the like of the battery pack can be realized; meanwhile, the size of a balanced current also can be regulated, and intelligent balance can be realized; by virtue of the system, a switch matrix driver and a common power supply switch controller can be omitted; the driving of an MOSFET transistor of each single battery gating module is completed by the battery monitoring module; and the driving of an MOSFET transistor of the active balance module is completed by the main controller, so that the intelligent charge-discharge function of the balanced current controlled by software is realized.

The invention discloses a power battery pack equalization circuit based on boost conversion and soft switching, and a realization method of the equalization circuit. The equalization circuit mainly comprises a microcontroller, a switching module, a BOOST conversion module and an LC (inductance-capacitance) resonance circuit, wherein the microcontroller gates battery monomers with maximum voltage and minimum voltage in any position of a battery pack on an equalization bus according to battery monomer numbers corresponding to maximum monomer voltage and minimum monomer voltage; and the microcontroller sends a pair of state-complementary PWM (pulse-width modulation) signals to control the LC resonance circuit, so that the LC resonance circuit alternately operates in charging and discharging states. The equalization circuit and the realization method effectively solve the problem that zero voltage difference of the battery monomers cannot be realized easily due to conduction voltage drop of electric and electronic devices; equalization current is increased; the equalization time is shortened; zero current switching equalization is realized; energy waste is reduced; the inconsistency among the battery monomers is improved effectively; and the equalization efficiency is improved.

The invention relates to an equalizing device of a battery management system, which comprises a bypass unit, wherein the bypass unit comprises a plurality of bypass devices, at least one part of the bypass devices are energy storage and energy conversion devices, preferably, the energy storage and energy conversion devices can be fans, super capacitors or quadratic chemical power sources, the bypass devices are used in an individual, parallel connection or parallel and series connection way, and the bypass unit also comprises a bypass indicating unit, a switch matrix unit, a battery unit, a data information acquisition unit and a central control unit. The invention also provides an equalizing method of the battery management system; through the invention, the equalizing efficiency is greatly improved under an equal condition, thereby not only shortening the equalizing time, but also satisfying the requirement for automatic and full heat dispersion of a power resistor. The invention enables the heat dispersion and the equalization of the system to be automatically realized without individually providing radiating device, can fully reduce the temperature of an equalizing system, and enables the case and bag design of a battery pack to be simpler and easier to operate and the productionization and the practicalization of a battery system to be further improved.

Providing a charge condition adjusting apparatus, which can shorten a time for equalization of each charge in unit cells, a low-voltage CPU selects each smallest unit cell in the each cell block, which has each smallest voltage between the both electrodes, from among plural unit cells structuring the cell blocks. The low-voltage CPU controls ON / OFF of a block-discharging switch to connect the both electrodes of each cell block and each block-discharging resistor for discharging the each cell block until the each voltage between the both electrodes of the selected smallest unit cell reaches the target voltage. Successively, the low-voltage CPU controls ON / OFF of a selecting switches and a cell-discharging switch to connect the both electrodes of each unit cell and each cell-discharging resistor to discharge the each unit cell until the each voltage between the both electrodes of the unit cells reaches the target voltage.

The invention discloses a relay switching-based lithium battery pack non-dissipative equalizing device, belongs to the technical field of battery protection and aims to provide the relay switching-based lithium battery pack non-dissipative equalizing device which has the advantages of high equalizing current, short equalizing time and high equalizing efficiency. The device comprises a battery pack, a current / current conversion unit, a plurality of double-pole relays and a detection control unit which are connected in series or parallel, wherein an input end of the current / current conversion unit is connected with the positive electrode and the negative electrode of the battery pack, while the output end is a path of isolated direct current power; one end of a normally open contact of each double-pole relay is connected in parallel with the positive electrode and the negative electrode of the output end of the current / current conversion unit respectively; the normally open contact at the other end is correspondingly connected with the positive electrode and the negative electrode of each single battery in the battery pack respectively; and the positive electrode and the negative electrode of each single battery in the battery pack are connected to the detection control unit through voltage detection flat cables respectively. High equalization of each single battery in the battery pack can be ensured by the device.

The invention provides a battery power equalization circuit which comprises battery packs, a voltage acquisition module, a switching circuit module, power transferring modules and a main control circuit module, wherein the switching circuit module comprises a plurality of group-inner switches and a plurality of driving circuit used for respectively driving the corresponding group-inner switches; the main control circuit module is used for judging whether powers among batteries are equalized according to voltage signals at two ends of each battery; and if not, sending control signals are to the corresponding driving circuits in the switching circuit module, so that the driving circuits can control the corresponding group-inner switches to be conducted / cut off. Therefore, the power equalization among all the battery packs is realized firstly via the two groups of power transferring modules arranged in parallel; and then the power equalization among the batteries in each battery pack is realized respectively via the two groups of power transferring modules arranged in parallel. As a result, the power equalization among all the batteries is realized. The battery power equalization circuit is simple to control, high in equalization precision and rapid in speed.

The invention discloses a multiphase interleaved converter based battery equalization circuit and a control method therefor. The equalization circuit comprises a controller, a plurality of half-bridge circuits, a plurality of electric reactors and a plurality of battery cells. The half-bridge circuits are all connected in parallel to two ends of a battery pack; and a middle point of each half-bridge circuit is connected with a negative electrode of a battery cell through an electric reactor. According to the circuit, MOS transistors of the half-bridge circuits are controlled by judging the magnitude of average voltage of the battery cells on the upper and lower sides of an inductor and average voltage of the battery pack, so that the equalization of any battery cell to any battery cell is realized. The circuit has the advantages of high equalization efficiency, simplicity for control, small volume, easiness for modularization and the like, and solves difficult problems of low equalization current and difficulty in realizing zero voltage difference equalization for a conventional Cell to Cell type equalization circuit.

The invention discloses a battery pack equalization system and control method considering the lifetime of batteries. The system comprises a sampling module, an equalization module, a battery lifetimeprediction module and a control module, the battery lifetime prediction module receives battery information acquired by the sampling module and predicts the lifetime of the batteries, and the controlmodule is used for receiving the battery information, acquired by the sampling module, of a battery pack and battery lifetime information obtained by the battery lifetime prediction module, calculating a voltage difference of adjacent single batteries, determining whether the voltage difference reaches a preset value, determining the adjacent single batteries required for equalization and the timerequired for equalization, and controlling the execution of the equalization module when the battery pack enters a charging and discharging state. The voltage difference of the adjacent single batteries is corrected by employing the battery lifetime information provided by the battery lifetime prediction module, the condition that the differences of the lifetime attenuation degrees of different single batteries cause inconsistent open-circuit voltages of the batteries is effectively considered, the energy waste caused by over-equalization can be avoided, the equalization efficiency is improved, the equalization time is reduced, and the lifetime of the batteries is effectively prolonged.

The invention discloses a self-adaptive fuzzy balancing control method based on the historical balancing speed. The method is suitable for a Pack to Cell balancing circuit; during each time of balancing, energy is supplemented to a battery monomer with the lowest voltage through a battery pack, the time consumed for each time of balancing is determined through the fuzzy control concept and referring to the time consumed for last time of balancing and the improved voltage difference, the time consumed for balancing is greatly shortened, the number of times of balancing switching is greatly lowered, the over-balancing phenomenon is eliminated, inconsistency between the battery monomers is effectively improved, and the balancing efficiency is improved.

The invention discloses a capacitive voltage balance system and a capacitive voltage balance method for a series-connected energy storage system. The capacitive voltage balance system is designed by adopting a voltage balance method on the basis of a conventional switching capacitor balance circuit. The voltage balance method has the main technical characteristics that a first-layer switching capacitor C4 and second-layer switching capacitors C5, C6 and C7 are added to a four-single-body series-connected energy storage element on the basis of a conventional switching capacitor network balance circuit, so that a path capable of directly transferring charges is formed between every two single bodies in a four-single-body series-connected energy storage unit. A voltage detection circuit unit feeds back the voltage consistency situation of a battery pack, and then a balance control unit sends a control signal to control the turn-on and turn-off of a corresponding switch, so that the transfer of electric quantity between a high-voltage battery and a low-voltage battery is realized; the voltage balance of each single body in the series-connected energy storage unit is completed finally, so that the potential risk caused by voltage inconsistency of the single energy storage bodies in the energy storage unit can be effectively reduced.

The invention discloses an LC bipolar resonant-based Cells-to-Cells equalization circuit and a control method thereof. During the equalization process, a microcontroller outputs four paths of rectangular wave driving signal of which frequencies are half of an LC resonant frequency, the phase difference is 90 degree and the duty ratio is 25% so that an equalization source unit and an equalization target unit are bipolarly and circularly connected to an LC resonant branch by a switch network, the LC resonant branch circularly works in states of positive polarity charging, positive polarity discharging, reverse polarity charging and reverse polarity discharging, and zero-current switch equalization of which energy is transmitted from the source unit to the equalization target unit is achieved. By the equalization circuit, equivalent release of a residual voltage of a resonant capacity C during the equalization process is achieved, the equalization source unit and the equalization target unit both can be adjacent arbitrary sections of Cells, the equalization circuit has the advantages of high power density, high equalization efficiency and control flexibility, and modular manufacturingis easy.

The invention discloses an external energy storage unit and LC quasi-resonance-based battery pack equalization circuit. The circuit of the invention comprises a series-connected battery pack, a gating switch, an equalizing bus, an LC series quasi-resonant unit, a buck-boost unit, an external energy storage unit, a voltage detection circuit and a controller; n energy storage batteries are connected in series so as to form the series-connected battery pack; the gating switch includes 2n bidirectional controllable switches; the positive poles and negative poles of the energy storage batteries are respectively connected with the positive pole and negative pole of the equalization bus through the bidirectional controllable switches; the equalization bus is connected in series with the LC series quasi-resonant unit, the buck-boost unit and the external energy storage unit sequentially; the controller is connected with the gating switch and the LC series quasi-resonant unit; and the voltage detection circuit detects the voltage signals of the energy storage batteries and the buck-boost unit and transmits the voltage signals to the controller. With the equalization circuit and method of the invention adopted, the battery pack can be equalized actively, fast and efficiently, the overcharging and over-discharging of the batteries can be prevented, and the consistency of the batteries can be improved.

The invention provides a lithium battery equalization control system and a control method thereof. The method comprises the following steps: an equalization power supply is arranged outside a batterypack; when the power difference between the batteries collected by a battery management system exceeds a preset value, the power supply and the battery pack are connected; the battery management system judges and finds out low-power batteries through a control circuit thereof according to the collected battery voltages; the control circuit makes gating switches and a power polarity reversal switchof an equalization circuit act, and sends a charging instruction to the power supply; and after the equalization of the low-power batteries is completed, the control circuit makes the equalization circuit switch off the corresponding gating switches and the power polarity reversal switch. Thus, the technical problem caused by the fact that the charging / discharging equipment is arranged outside inthe existing battery management system equalization mode is solved, one equalization power supply can equalize multiple battery packs, the number of components of the lithium battery equalization control system is reduced, and the cost and failure rate of the battery management system are reduced.

The invention discloses an active equalizing system for a multi-path energy transmission battery. The active equalizing system for the multi-path energy transmission battery comprises a total battery pack, an equalizing power supply unit, a battery equalizing module, an energy buffer module and an equalizing system host; the total battery pack is concatenated by more than one battery blocks and electrically connected with the battery equalizing module; one end of the equalizing power supply unit is electrically connected with the equalizing system host and the battery equalizing module respectively, and the other end is electrically connected to the battery pack; each battery equalizing module is electrically connected with the energy buffer module; the energy buffer module is an energy buffer device assisting the battery equalizing module, and the energy buffer module is connected to each battery equalizing module electrically; the equalizing system host analyzes, processes and displays the information sent by each battery equalizing module through the CAN bus, and controls the control strategy of each battery equalizing module. According to the invention, the structure design of the active equalizing system for the multi-path energy transmission battery is simple and reasonable, the cost is reduced, the stability of the system is improved, the inconsistency of the battery pack is improved, and the service life of the battery is extended.

The invention discloses a multi-level active equalization circuit of an energy storage battery system and a control method thereof. A battery energy storage system is divided into a plurality of modules by adopting a multi-level active equalization structure; wherein the active equalization circuit comprises an intra-group equalization circuit and an inter-group equalization circuit, the intra-group equalization circuit comprises a battery state information acquisition circuit, an intra-group switch array, an intra-group bidirectional DC-DC circuit and a slave MCU, and the inter-group equalization circuit comprises an inter-group switch array, an inter-group bidirectional DC-DC circuit and a master MCU; intra-module equalization is achieved through active equalization in the modules, and equalization between the modules is achieved through adoption of the module equalization main circuit. Effective utilization of energy in the energy storage battery system can be achieved, the overallcapacity and the power performance of the battery pack can be effectively improved, and meanwhile, the equalization time is shortened.

The invention provides a control method and device of the passive equalization of a battery pack, a battery system and a vehicle. The method comprises a step of obtaining the temperature data of each single battery of the battery pack in historical use, a step of determining at least one single battery with the need of passive equalization in the battery pack according to the temperature data of each single battery, and a step of opening the passive equalization switch of the at least one single battery in the process of charging or discharging the battery pack. In the embodiment of the invention, in the process of charging or discharging, the determined single battery with the need of passive equalization can be equalized in advance, thus the equalization time can be effectively shortened, the problem that the charging of partial single batteries is completed but the equalization is not completed can be avoided, and the equalization effect is improved.

The invention discloses an equalization circuit topology structure of a layered battery and a battery equalization method. The equalization circuit topology structure comprises a plurality of batteries which are sequentially connected in series, wherein the number of the batteries is larger than or equal to 2, a first control switch and a second control switch are sequentially connected in serieswith two ends of each battery, first equalizer circuits are further connected in series between a node between the first control switch and the second control switch and the batteries, an energy storage capacitor is connected in series between a node between two adjacent batteries and a node between two first equalizer circuits, and each first equalizer circuit comprises a protection diode and anMOS switch which are connected in parallel. By the equalization circuit topology structure of the layered battery and the method, the equalization efficiency in the circuit with relatively many batteries connected in series can be greatly improved, the bidirectional energy conversion capability is high, the modular design is simple, and all single batteries are not needed to be involved during theequalization process.

The invention relates to a power battery balancing device and method. The device includes balancing modules of battery cells, which are used for the balancing operation of all battery cells, wherein each balancing module is connected in parallel with the corresponding battery cell to form a battery cell charging circuit; all the balancing modules are connected mutually through a CAN bus and are connected to an upper computer through the CAN bus; a DC power supply is connected to the input of each balancing module; a normally open relay is connected in series with an output end of each balancing module. According to the invention, the balancing modules are the same in structure, mutually and independently control the battery cells in a one-to-one correspondence manner, the balancing modules of different amount can be equipped as per the battery packs of different series for balancing, different balancing strategies can be equipped with DC / DC modules in the balancing modules conveniently and flexibly, the balancing requirement of the battery packs of different capacities and nominal voltages of battery cells can be met through setting the balance voltage and balance current, and the balance modules of all the battery cells can be used for balancing simultaneously, thereby saving the balancing time and improving the balancing efficiency.

The invention relates to a battery module balance control device and method. The device comprises: a battery module, a data acquisition module, a SOC estimation module, a fuzzy controller and an equalization circuit module, wherein the battery module is connected with the data acquisition module, the data acquisition module is connected with the SOC estimation module and the fuzzy controller, theSOC estimation module is connected with the fuzzy controller, the fuzzy controller is connected with the equalization circuit module, and the equalization circuit module is connected to the battery module. According to the method and the device, the battery real state judgment accuracy can be improved, the equalization current can be increased, the equalization time can be shortened, the control cost is low, equalization can be realized under the condition that the hardware structure of the current battery management system is not changed, the fault tolerance is high, and the occurrence of anover-equalization problem can be effectively prevented.

The invention discloses a system and a method for diagnosing and maintaining energy storage battery packs. The system comprises an energy storage battery pack module, a BMU (battery management unit) module, a master control module and a maintenance module. A plurality of single batteries are serially connected with one another to form the energy storage battery pack module; the BMU module is used for acquiring total voltages of the energy storage battery pack module, single voltages of the various single batteries, main circuit currents and battery temperatures and transmitting single voltage, main circuit current and battery temperature information to the master control module; the master control module is used for receiving the single voltage, main circuit current and battery temperature information and screening the single batteries according to the single voltage, main circuit current and battery temperature information, and screened single batteries include qualified batteries and unqualified batteries; the maintenance module is used for receiving unqualified battery information transmitted by the master control module, maintaining the unqualified batteries and transmitting maintenance information to the master control module in a return manner. The system and the method have the advantages that whether requirements of energy storage systems can be met by current performance of the batteries or not can be discriminated according to power characteristics of the batteries, alarm can be sent for the unqualified batteries, and the qualified batteries need to be timely charged and maintained.

The invention discloses a battery pack double-layer topological structure equalization circuit and method. A first-layer topological equalization circuit comprises a multi-winding transformer, a control switch, a single battery in a small battery pack, a control switch K1_1 and a secondary winding of the multi-winding transformer, wherein the control switch K1_1 is connected with the secondary winding of the multi-winding transformer; the small battery pack and the control switch K1 are connected with a primary winding of the multi-winding transformer; the second-layer topology equalization circuit comprises a transformer and two control switches; a primary winding of the transformer, the control switch S1 and the main battery pack are connected; and a secondary winding of the transformer,the control switch S1_1 and the small battery pack are connected. Multiple groups of small battery packs or multiple battery monomers can be equalized at the same time, the battery equalization speedis greatly improved, the battery equalization time is shortened, and the equalization efficiency is improved.

The invention provides a large-equalizing-current battery pack equalization method which is characterized by, in a battery low-voltage area, utilizing externally-arranged equalizing devices to enable all batteries to discharge to VE with a large equalizing current IJ, and allow the batteries to be close to empty, thereby realizing equalization of the batteries of a battery pack. The equalizing action is realized in the battery low-voltage area; and the externally-arranged equalizing devices are used to allow all the batteries to realize quick and effective equalization through the equalizing method of allowing the batteries to be close to empty with the large equalizing current, so that temperature rise in the battery pack is not caused, and the cycle life of the battery pack is improved.

The invention discloses an active equalization circuit for echelon utilization of retired power batteries, which comprises a data acquisition module and a main control unit MCU. The data acquisition module is used for respectively acquiring voltage and current data of each single battery in the power batteries, and the output end of the data acquisition module is connected with the main control unit MCU; the circuit further comprises a PWM drive circuit, a bidirectional DCDC equalization module, a capacitance equalization module and a switch array, the output end of the main control unit MCU is connected with the PWM drive circuit, and the output end of the PWM drive circuit is connected to the switch array and used for controlling on and off of the switch array. The positive electrode andthe negative electrode of each single battery are connected with the two ends of the bidirectional DCDC equalization module and the capacitance equalization module respectively, and the switch arrayis used for controlling on-off between the single batteries and the bidirectional DCDC equalization module and on-off between the single batteries and the capacitance equalization module respectively.The circuit has the advantages that the circuit is simple in structure, equalization is reliable, and rapid equalization can be achieved for power battery packs which are high in capacity level and connected in series.

The invention relates to a lithium battery pack stepless active and passive equalization circuit and method. The circuit comprises an equalization direction selection circuit, a switch array and an LCresonance energy storage and energy transfer branch with three differentiated capacities, and the passive equalization circuit adopts a resistance shunt structure and comprises a measurement and control circuit composed of voltage, current and temperature. Temperature interference factors are added into the non-level active and passive equalization method, a dynamic double-threshold criterion with voltage, SOC and temperature as input quantities is obtained, and the active equalization circuit and the passive equalization circuit are respectively accessed by taking state of charge (SOC) as ademarcation standard, so that the purpose of reducing invalid cyclic charging and discharging times is achieved, the equalization efficiency is improved, and the reduction speed of the cycle service life of the lithium-ion battery pack is delayed. According to the invention, useless cyclic charging and discharging times can be reduced, the equalization time is shortened, the equalization time in acharging state is shortened by about 15% compared with a single threshold voltage equalization method, and the equalization time in a discharging state is shortened by about 19%.

The invention discloses a method and a device for data reconstruction. The method comprises the following steps: determining the number T of hot standby VDs (Virtual Disks), wherein the hot standby VDs are those which do not participate in VDG (Virtual Disk Group) reconstruction on a normal disk; determining the number S of the hot standby VDs to be converted into idle VDs from the T hot standby VDs, wherein T and S are both natural integers which are greater than 0, and S is smaller than T; selecting the S hot standby VDs from the T hot standby VDs, converting the S hot standby VDs into the idle VDs, and converting the S idle VDs on a dilatation disk into hot standby VDs; enabling the hot standby VDs on the normal disk and the dilatation disk to participate in athe VDG reconstruction. By applying the method disclosed by the invention, the dilatation disk which is newly added is enabled to more participate in a reconstruction process, so that the efficiency of data reconstruction is increased, and meanwhile, the equalization time after reconstruction can be shortened.

The invention relates to the technical field of battery balancing and provides a power battery pack balancing system and method. The power battery pack balancing system comprises a battery management system, a central controller, a balancing module, multiple first switches, multiple second switches, multiple first balancing interfaces, multiple second balancing interfaces, at least one first power battery pack and at least one second power battery pack; the central controller enables the first power battery pack with the maximum electrical charge state value to charge the second power battery pack with the minimum electrical charge state value through the balancing module, the first switches and the second switches are controlled to be simultaneously turned off until the electrical charge state values reach an electrical charge state mean value, the battery management system is driven to work until the electrical charge state values of all the first power battery packs and the second power battery packs reach the electrical charge state mean value, the service life of power batteries is prolonged, the balancing energy consumption is small, the balancing efficiency of the power batteries is improved remarkably, and the balancing time of the power batteries is shortened.