145results about How to "Improve uniform efficiency" patented technology

The invention relates to a power source balancing method of an electric car. The power source balancing method comprises the following steps of: (1) establishing an actual SOC (State of Charge) value of each single battery; and (2) carrying out charging / discharging balance on the single battery according to a difference value between the actual SOC value of each single battery and an average SOC value of a battery pack, and a difference value between voltage of the each single battery and average voltage of the battery pack. The invention provides a storage battery active balancing scheme; an SOC parameter of the single battery is used as a balance object to improve an amper-hour integral method; the battery capacity can be revised in real time and the accurate SOC value is obtained; and the capacity difference between the single batteries in a storage battery pack can be reduced, the balance efficiency is high, the loss is small, and the service life of the battery pack is greatly prolonged.

The invention provides an equalization circuit of a battery pack and an equalization method. The equalization circuit comprises the battery pack, a battery management unit, a controllable bidirectional switch array module and an energy transfer module, the energy transfer module comprises a charging unit, a discharging unit and a super capacitor module; the controllable bidirectional switch array module is used for switching on or switching off the electric connection between battery cells and the super capacitor module according to an equalization control command of the battery management unit; the super capacitor module is used for charging and discharging the battery cells which meet equalization conditions; the battery management unit is used for controlling the voltage of the super capacitor module, making the voltage of the super capacitor module to be equal to the average voltage of the battery pack and sending the equalization control command to the controllable bidirectional switch array module to charge and discharge the battery cells which meet the equalization conditions. By means of the equalization circuit of the battery pack, the battery cells in the battery pack are equalized, and the equalization circuit of the battery pack has the advantages of being efficient, low in heat, long in service life and the like.

The invention relates to a charge-discharge equalizing circuit of a multi-monomer tandem dynamic lithium battery, comprising a master control module and a group of equalizing modules, wherein the group of equalizing modules are communicated with the master control module and correspondingly connected with a group of monomer batteries which are sequentially connected in series; each equalizing module comprises a flyback transformer, two switches and one or more than two parallel capacitor banks; one winding of the flyback transformer of each equalizing module is connected with the positive and negative poles of the corresponding monomer battery; the capacitor banks of each equalizing module are connected with the winding in parallel; the other winding is connected with the positive and negative poles of the monomer battery which is adjacent to and sequentially connected to the above monomer battery; and each winding return circuit is connected with one switch in series. The equalizing circuit realizes energy balance among all the monomer batteries, has the advantages that the equalization is lossless, the equalizing current is large, the equalizing efficiency is high, the expandability is good and the implementation is easy, and the purposes of quick large-current charging, enhancement of battery safety performance, improvement of discharging capacity and service life of the batteries and the like can be realized.

The invention discloses an equalization circuit based on a Buck-Boost convertor and a bidirectional LC (inductance capacitance) resonant convertor as well as an implementation method. The equalization circuit comprises a microcontroller, the Buck-Boost convertor, the bidirectional LC resonant convertor, an option switch module, an equalization busbar, a battery pack and filter capacitors. According to the equalization circuit, by means of control of output voltage of the Buck-Boost convertor as well as the bidirectional LC resonant convertor, soft switching equalization of Pack to Cell or Cell to Pack can be realized, the equalization circuit has the advantages of high efficiency, simplicity in control, small size, switching loss avoidance, easiness in modularization and the like, and the defect that the traditional Pack to Cell equalization circuit cannot deal with the condition that certain cell in a pack has higher voltage while other cells are in equalization is overcome.

The invention discloses a bus-based battery pack equalizer circuit. The bus-based battery pack equalizer circuit comprises N batteries; each battery is connected with a corresponding equalizer circuit and the equalizer circuit is connected to a controller; each battery is connected with one equalizer circuit and each equalizer circuit is connected to one controller; the batteries correspond to the equalizer circuits one to one and the equalizer circuits correspond to the controllers one to one; the controllers are used for controlling the equalizer circuits according to the energy information of the battery pack, and thus realizing two-way flow of energy between the battery module and an energy transmission bus and realizing equalized energy storage of the batteries; the N controllers are connected in parallel to a data bus and the N batteries are connected in parallel to an energy transfer bus; N is greater than or equal to 2.

A battery equalizer for equalizing electrical energy of a first battery unit and a second battery unit includes a first diode, a first switch, a second diode, a second switch, a capacitor and an inductor. The components are electrically connected to be able to form different circuit loops to equalize the electrical energy of the two battery units.

The invention discloses a system and a method for modularizing a battery pack balancer based on multi-winding transformers. Through anti-parallel connection of secondary sides of an odd number and an even number of the multi-winding transformers, balancing in modules and between the odd / even number of modules is realized based on forward conversion; the balancing between the odd number and the even number of the modules and the automatic demagnetization of the multi-winding transformers are realized based on flyback conversion; during control, direct, automatic and synchronous balancing from any battery monomer to any battery monomer in a battery pack can be realized just by a pair of control signals which are complementary in states, so that the balancing efficiency and the balancing speed are greatly increased, and the inconsistency between battery monomers can be effectively improved. The system and the method, disclosed by the invention, have the advantages that the balancing efficiency is high, the balancing speed is fast, the volume is small, the cost is low, the reliability is high, modularization is easy, the control is simple, a voltage detection circuit and a demagnetization circuit are not required, and the like.

The invention provides an active balanced battery management system, which comprises a host computer and a CAN communication module, wherein the host computer transmits a control instruction to the battery management system through the CAN communication module; the battery management system transmits data to the host computer through the CAN communication module and is connected with an on-board control system and a charger through the CAN communication module; and the battery management system is also connected with a voltage collection module, a current collection module and a temperature collection module through an RS232 and obtains AD sampled data of voltage, current and temperature of a battery. A novel SOC calculation mode is provided, so that the problem that the prior art is inaccurate in calculation accuracy of the battery capacity is solved. The parameters of an upper limit and a lower limit of the battery capacity, charging and discharging current, a battery temperature and the like are set through the host computer; and the battery is effectively protected. The invention provides a novel charging mode standard, so that the battery can be more effectively charged.

The invention provides an active balancing circuit of a power Li-ion battery module and a balancing method. The active balancing circuit of the power Li-ion battery module and the balancing method belongs to the technical field of motor automobile battery management. The balancing circuit comprises a Li-ion battery group, a charging-discharging switching group unit, a charging-discharging bus unit, an energy transferring circuit and a balancing controlling device, wherein the Li-ion battery group is connected with the charging-discharging bus unit by the switching group unit. Two sides of the energy transferring circuit are further connected with the charging-discharging bus unit. The balancing controlling device is connected with the Li-ion battery group, the charging-discharging switching group unit and the energy transferring circuit. Voltage of a Li-ion single body battery is monitored in real time, the Li-ion single body battery requiring the charging-discharging of the switching group unit is controlled and the energy transferring circuit is controlled, thus the charging-discharging of the selected Li-ion single body battery is achieved. Defects of the existing power Li-ion battery module are overcome. The active balancing circuit of the power Li-ion battery module and the balancing method have the advantages of being simple to control, large in balanced current, high in balancing efficiency and low in cost.

The invention discloses an electric quantity equalization method of a power battery, a battery management system and a dynamic electric vehicle. The method comprises the following steps of detecting a battery parameter of each single battery included by a battery pack in predetermined time, wherein the battery parameter at least includes an open-circuit voltage; according to the open-circuit voltage of each single battery, determining at least one single battery to be adjusted in the battery pack and determining an electric quantity which needs to be discharged by each single battery to be adjusted; and based on the electric quantity which needs to be discharged by each single battery to be adjusted, carrying out electric quantity equalization on each single battery to be adjusted. In the prior art, end voltage consistency is taken as an equalization target so as to carry out equalization on an electric quantity of the battery, and the above condition is limited by the state of the battery. In the invention, the above technical problem is solved.

The invention discloses an Adjacent-Cell-to-Cell equalization circuit based on LCL resonant transformation and an implementation method. The equalization circuit comprises a microcontroller, a plurality of LCL resonant transformation modules and single cell bodies. Every two adjacent single cell bodies share one LCL resonant transformation module. Each LCL resonant transformation module and the corresponding single cell bodies are connected with the microcontroller. According to every two adjacent single cell bodies with the higher voltage and the lower voltage respectively, the microcontroller sends a pair of PWM signals with the complementary states to corresponding MOS transistors of the LCL resonant transformation module, so that the MOS transistors work in the charging state and the discharging state alternately, and energy is transmitted from the single cell body with the higher voltage to the single cell body with the lower voltage. When the PWM frequency is equal to the LCL natural resonant frequency, zero-current switching equalization is achieved. The equalization circuit is high in efficiency, large in equalization current and easy to control, and the problem that a traditional Cell-to-Cell equalization circuit is large in switching loss, and cannot achieve zero-voltage-difference equalization is solved.

The invention discloses a multi-input transformation-based dual-layer active balance circuit and an implementation method. The multi-input transformation-based dual-layer active balance circuit comprises a microcontroller, bottom-layer balance units, a top-layer balance unit and switching relays; the microcomputer sends a path of PWM signals to control the bottom-layer balance units to work alternately under a charge state and a discharge state, so that energy balance between adjacent battery units can be realized; the microcontroller sends two paths of identical PWM signals to control the top-layer balance unit to work alternately under a charge state and a discharge state, so that energy balance between adjacent battery modules can be achieved; and the microcontroller sends two paths of switching signals to control the switching of the relays, so that the moving direction of energy balanced between adjacent modules can be controlled. With the multi-input transformation-based dual-layer active balance circuit and the implementation method of the invention adopted, the inconsistency of the battery units and the inconsistency of the battery modules can be effectively improved, and the problems of low balance efficiency, low balance speed and difficulty in modular expansion of a traditional balance circuit can be solved.

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 relates to a battery pack charge-discharge balancing method, balancing device and maintenance device which aims at solving the problem of large voltage deviation among batteries, small charge-discharge capacity and short service life caused by poor consistency of a battery pack when the batteries are serially connected into a pack for use. During the charge and discharge, the battery pack charge-discharge balancing device can calculate the voltage deviation among the batteries and judge the consistency of the battery pack by detecting voltage of the batteries. When the voltage deviation exceeds the preset voltage deviation range, a controller transmits an instruction to control a balancing module to reduce the voltage of the battery pack to perform energy-nondestructive voltage supplement on the battery with the lowest voltage, difference among the batteries can be reduced, the charge-discharge capacity of the battery pack is improved, and the service life is prolonged. The battery pack charge-discharge maintenance device is independent of a storage battery power supply system and used for maintaining the storage battery power supply system regularly.

The invention relates to an equalization circuit realizing parallel charging and selective single cell battery equalization discharge and a control method thereof. The equalization circuit is composedof a battery pack, a DC / DC converter, Mosfet switches with anti-parallel diodes, a bus switch K1, a bus switch K2, a bus switch P1, a bus switch P2, a switch Q1, a switch Q2, a switch Q3 and a switchQ4. The equalization circuit can realize parallel charging, when any single cell battery reaches the set cutoff voltage, the single cell battery is isolated from a charging circuit, finally all single cell batteries are stopped charging when reach the set charging cutoff voltage, and the forced balance purpose is achieved. According to the equalization discharge, the battery pack is connected tothe DC / DC converter in parallel to perform equalization on the single cell battery with the lowest state of charge (SOC) in the battery pack. During discharging, the inconsistency between all the single cell batteries can be effectively reduced.

The invention discloses a bidirectional equalization circuit. The bidirectional equalization circuit is characterized in that an equalization switch array is correspondingly connected with a plurality of battery cells one to one; a micro-control unit samples the plurality of battery cells, obtains the average voltage through calculation, calculates the absolute value of the difference between the maximum voltage and the average voltage, and the absolute value of the difference between the minimum voltage of the plurality of battery cells and the average voltage so as to obtain the high difference and the low difference, and compares the magnitude of the high difference with the magnitude of the low difference; if the high difference is greater than the low difference, the micro-control unit drives a passive equalization circuit to start and controls a switch corresponding to the maximum voltage, in the equalization switch array to start, and then the passive equalization circuit communicates with the battery cell corresponding to the maximum voltage; and when the high difference is lower than the low difference, the micro-control unit drives an active equalization circuit to start and controls a switch corresponding to the minimum voltage, in the equalization switch array to start, and then the active equalization circuit communicates with the battery cell corresponding to the minimum voltage. The bidirectional equalization circuit realizes bidirectional equalization of high and low voltage of circuit cells.

The invention relates to a charge-discharge technology for batteries, and provides a battery historical data based active equalization method. The active equalization method specifically comprises the steps of step 1, measuring voltage characteristic curves of different types of batteries under specified conditions; step 2, when a charging process is started, checking the electric quantity corresponding to the voltage of each single battery in the battery pack when the last charging process is finished; predicting the electric quantity of each single battery when the current charging process is finished without performing equalization according to the equalization electric quantity for each single battery in the last discharge process; step 3, calculating the average value of the predicted electric quantities of all the single batteries, and ranking the predicted electric quantities from higher to lower in sequence; finding out m single batteries with the maximum predicted electric quantity and n single batteries with the minimum predicted electric quantity; and taking the difference values between the predicted electric quantities of the single batteries and the average value of the predicted electric quantities of all the single batteries as the equalization electric quantity required values of the single batteries; and step 4, performing equalization based on the equalization electric quantity required values. According to the active equalization method, the residual electric quantity levels of the battery packs tend to be uniform through the active equalization, and / or the capacity of the battery pack is higher than that of the series-wound branch with the minimum capacity in the battery pack.

The invention discloses a multi-winding-transformer-based automatic battery equalization circuit and an implementation method thereof. The automatic battery equalization circuit comprises a pluralityof battery groups, a micro controller, and multi-winding transformers. Each battery group consists of a plurality of single battery bodies and is provided with one multi-winding transformer; secondarywindings of all multi-winding transformers are connected in parallel and are connected with the corresponding battery groups by diodes; and positive and negative electrodes of the single battery bodies are connected with the corresponding transformer windings by switching tubes. The micro controller controls turning on or off of all switching tubes simultaneously. Automatic and simultaneous equalization from any single battery body to any single battery body among the multiple battery groups is realized by one path of PWM control signals.

The invention relates to a double-level-bridge-arm series connection storage cell pack efficient equalizer topology circuit and a control method of the double-level-bridge-arm series connection storage cell pack efficient equalizer topology circuit, and belongs to the technical field of storage cell pack energy equalizing management. The topology circuit comprises an upper bridge arm power switch matrix N, a lower bridge arm power switch matrix S, an inductor L, a voltage source E, a main control switch M1 and a main control switch M2. When a cell pack is in the discharging or static state, the jth cell (Cell j) with the lowest electrical charge state and the lowest end voltage in the cell pack is charged through an equalizing circuit, other single cells in the same pack are not affected, and the equalizing energy is transferred to the Cell j from the equalizing device; when the cell pack is in the charging state, the ith cell (Cell i) with the highest electrical charge state or the highest end voltage is discharged through the equalizing circuit, other single cells in the same pack are not affected, and the equalizing energy is transferred to the equalizer from the Cell i. The topology circuit is simple in principle, continuous in equalizing current, high in controllability and high in equalizing efficiency.

The invention discloses a battery pack balancing control system and a control method on the basis of a dynamic balance point. The system comprises a battery pack, a voltage sampling circuit, a balancing main circuit and a balancing control circuit. The balancing control circuit is used for comparing a voltage value of each single battery and respectively regulating frequencies of power switch tubes corresponding to the single batteries and controlling the frequencies of the power switch tubes to track a balance frequency of the battery pack in a dynamic balance state when a voltage difference of different single batteries exceeds a preset threshold value, wherein the dynamic balance state is a state when energy released by each battery of the battery pack and energy adsorbed by the battery in each switching period are equal; and the balance frequency is the frequency of each power switch tube in the dynamic balance state. According to the invention, all the single batteries in the battery pack can almost simultaneously reach balance, the balancing speed and efficiency are improved, overcharge and over-discharge damage caused by inconsistency of the single batteries is prevented, and service life of the battery pack is prolonged.

The invention provides a method for equalizing the electric quantity of batteries. The method comprises the following steps of: dividing series single batteries to be equalized into a plurality of battery sub-groups in a mode of taking even batteries as a group; detecting terminal voltages of all battery sub-groups, discharging the battery sub-groups having high voltages, and transferring redundant electric quantity to the battery sub-groups having low voltages to equalize the electric quantity of all battery sub-groups; detecting the terminal voltages of all single batteries in all battery sub-groups, discharging the single batteries having high terminal voltages in all battery sub-groups, and transferring the redundant electric quantity to the single batteries having low terminal voltages in the battery sub-groups to equalize the electric quantity of all single batteries in the battery sub-groups; and cyclically executing equalization of the electric quantity among the groups and equalization of the electric quantity in the groups until the electric quantity of all series single batteries is equalized. Moreover, the invention provides a corresponding equalizer. The method and the equalizer provided by the invention are simple and easy to operate, low in cost, high in equalization speed and high in equalization accuracy.

The invention relates to a multifunctional control system and a control method of a battery used in a substation, which is characterized in that the multifunctional control system comprises a currentacquisition module, an input end of the current acquisition module is connected with a current sensor, and an output end is connected with an input end of an A / D converter. The input end of the temperature acquisition module is connected with the temperature sensor, and the output end is connected with the input end of the A / D converter. The output of A / D converter is connected with CPU through I / O interface. The CPU is also connected with human-computer interaction module, discharge load and voltage balancing module through I / O interface, and the discharge load and voltage balancing module are electrically connected with each single battery respectively. The control method comprises the following steps of: balancing control of a battery pack; SOC estimation of battery pack; measurement ofinternal resistance of battery pack.

The invention discloses a direct current step-up / step-down circuit. The direct current step-up / step-down circuit is characterized in that: an anode of a battery unit is connected with one end of a third switching device; the other end of the third switching device is connected with one end of an energy storage inductor and one end of a first switching device; the other end of the energy storage inductor is connected with one end of a second switching device and one end of a fourth switching device; the other end of the fourth switching device is connected with a cathode of the battery unit; the other end of the first switching device is connected with a direct current bus cathode of a battery set; the other end of the second switching device is connected with a direct current bus anode of the battery set; and the states of the first, second, third and fourth switching devices are controlled by a control circuit (U1). The step-up operation or step-down operation of a direct current power supply is realized by controlling the on / off timing sequence of corresponding switching devices. The direct current step-up / step-down circuit has the advantages of flexible control of step-up / step-down proportion, independent working of modules, simple structure, low cost, high efficiency, high reliability and capability of realizing standard and batch production.

The invention relates to a rapid low-loss voltage balancing system of a super capacitor and a control method of the rapid low-loss voltage balancing system. A double-layer capacity voltage balancing circuit is used for performing voltage balancing on an energy storing unit, increasing energy transferring channels and improving balancing speeds and in addition, achieving zero-current on-off of a power switching element through a series resonance subcircuit based on a soft-switching technology and reducing loss in switching. With the voltage balancing circuit, a series connection super capacitor set can achieve voltage balancing in a short time. Reliability and safety of all units which works for a long time can be improved. Owning to the series connection resonance subcircuit, loss of switching of the circuit is little. As the control method can determine a working mode of the voltage balancing circuit, the voltage balancing circuit is little in power consumption in a standby state. The whole voltage balancing system is faster in speed, less in loss and higher in efficiency.

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 a cell equalization apparatus possessing a heating function. The cell equalization apparatus possessing the heating function comprises a plurality of independent cell module equalization circuits corresponding to a cell module. Each cell module equalization circuit comprises an equalization control switch and an equalization resistor which are connected in series. The equalization resistor is a thin-sheet-type large power heating resistor which can be used to heat a cell. The thin-sheet-type large power heating resistor is formed by an insulation heat conduction thin sheet and a heating wire arranged in the insulation heat conduction thin sheet. The thin-sheet-type large power heating resistor is fixed to a cell module sidewall or a bottom surface and is tightly and uniformly contacted with a monomer cell shell used for forming the cell module. The cell equalization apparatus possessing the heating function can be served as a heating unit of cell system heat management under a low temperature environment and also can be served as the equalization resistor under a normal temperature environment. Equalization resistor power in the equalization apparatus is large, equalization efficiency is high and a temperature rise of the equalization resistor during equalization is small.

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.

Provide is a battery management and lossless equalization system which is used to manage and control the consistency of the monomer cells in an electric automobile battery. A charger is connected with a load through a power battery. A cell management module is in a cascade connection with a display unit, a central communication unit and a panel operation unit through a central processor. The central processor is connected to an electric automobile energy management system. It is possible to carry out a real-time on-site measurement on power battery total voltage, total current and various parameters of the monomer cells and carry out estimation on the inconsistency of the monomer cells. A dynamic on-site lossless equalization is carried out to charging, discharging and standing of the monomer cells. Meanwhile, necessary control is implemented to ensure the safety of the battery and prolong the service life of the battery. According to the invention, the inconsistency of the monomer cells can be equalized, there is no energy loss, the equalization efficiency is high, the equalization effect is good, the inconsistency difference of the voltages of the monomer cells is less than 20mv and the precisions of voltage measurement and temperature measurement are high.

The invention discloses a novel light emitting diode (LED) packaging structure. The structure comprises: a pedestal; a recessed cavity, which is formed in the pedestal; a heat sink, which is fixed in the recessed cavity; a cup bowl, which is formed on the heat sink; and an LED chip, which is fixed in the cup bowl. Besides, a pair of conductive feet are extended and are fixed in the pedestal; the LED chip is electrically connected with the conductive feet; a lens is formed on the pedestal and enables the LED chip and a part of conductive feet to be sealedly capped; and an external surface of the lens are provided with a layer of phosphor coating. According to the LED packaging structure provided in the invention, a traditional LED packaging mode is broken; a phosphor coating is directly transferred from an original chip surface to a surface of a lens, so that the phosphor coating is thoroughly far away from an LED chip and a luminous decay is substantially reduced; moreover, a shape and a thickness of the phosphor coating can be controlled accurately and an excitation area of the phosphor coating can be enlarged, so that an occurrence of a yellow ring can be avoided, a light extraction efficiency is improved and color temperatures of the phosphor coating are highly consistent.

The invention discloses a passive equalization control method, which includes: 1. A passive equalization control circuit is preset, and a power resistor and an equalization switch are connected in parallel to each single battery of a plurality of series-connected single batteries; The battery is charged. When charging for the i time, the micro-control unit detects the voltage of multiple single cells. When the voltage of m single cells exceeds the threshold voltage, it records the battery number of m single cells and 3. When charging the i+1th time, directly perform voltage balancing on the m cells in the i-th charging; when the voltage of the m cells exceeds the threshold voltage, cover Record the battery number of the m cells in the i+1th charge and perform voltage equalization on the single cells; 4. Repeat step 2 and step 3 in sequence to perform voltage equalization. This method realizes the effect of prolonging the equalization time and improving the equalization efficiency.