Equalization circuit and method for high-magnification frequent charging and discharging energy storage module

Abstract

The invention discloses an equalization circuit and method for a high-magnification frequent charging and discharging energy storage module, and solves the problems that an existing method is poor in adaptability to frequent and high-magnification charging and discharging scenes, and excessive charging and discharging and even reverse equalization are likely to occur due to battery polarization voltage misleading. The structure comprises a control unit and equalization capacitors, the equalization capacitors are connected with corresponding energy storage monomers in parallel, the high-voltage side and the low-voltage side of each equalization capacitor are connected respectively, a selective switch group is connected between the equalization capacitors, the control unit sorts the voltages of the energy storage monomers in charging and discharging states respectively, the charging sequence and the discharging sequence are matched, and the equalization capacitors are connected with the equalization capacitors. And according to the matched sequence, sequentially controlling the on-off of the equalization capacitor selection switches corresponding to the energy storage monomers, and carrying out equalization operation. According to the invention, the test voltages of the charging and discharging states of the energy storage monomer are used, the charging and discharging voltages are sorted and matched and then are sequentially balanced, and the interference of impedance on voltage judgment is avoided to a certain extent by using the characteristic of opposite polarization loss of the charging and discharging states.

Description

Technical Field

[0001] The present invention relates to the field of electronic information technology, and in particular to an equalization circuit and method for a high-rate frequent charging and discharging energy storage module. Background Art

[0002] Existing electrochemical energy storage units, such as ion batteries and supercapacitors, usually build modules in the form of multiple series connections because of their relatively low single-cell voltages, to increase the total output voltage and facilitate subsequent voltage-current conversion and charge-discharge control. Although the series structure can ensure that the amount of electricity flowing through each energy storage unit is consistent, due to the influence of each unit's internal resistance, self-discharge rate, coulomb efficiency, etc., there are differences in the amount of electricity that can be ultimately released. Over time, the difference in the amount of electricity stored in each series unit increases, affecting the charge-discharge capacity of the module and even endangering the safe use of energy storage devices.

[0003] In order to suppress the difference in the amount of electricity in the above energy storage units, a bypass can be connected in parallel to each monomer, and the monomer power can be flexibly adjusted according to the battery voltage or estimated SOC to achieve balanced and unified power. Generally speaking, energy storage monomers can be connected in parallel with switch resistors to consume the higher power of some monomers; or connected in parallel with switch inductors / capacitors to achieve charge migration between different monomers; or connected in parallel with small transformer power supply circuits to charge and discharge monomers with abnormal capacity. The above schemes have their own advantages and disadvantages in terms of cost, energy efficiency, and balancing time, and different forms of circuit structures are disclosed.

[0004] According to the principle of power balancing, the accuracy of the remaining power estimation has a great impact on the balancing effect of the energy storage unit. The above balancing logic mainly relies on the single cell voltage to estimate the remaining power, which is suitable for low-rate charging and discharging conditions and is mostly static, that is, usually for capacity-type energy storage needs. At this time, the voltage is highly correlated with the battery power, and relying on the single cell voltage to estimate the power is relatively accurate.

[0005] However, with the development and update of energy storage technology, its maximum charge and discharge rate continues to increase, and power applications such as primary frequency modulation and kinetic energy and potential energy recovery are increasing year by year. In this high-frequency, high-rate charge and discharge scenario, the impact of the impedance of the energy storage device on the voltage cannot be ignored. At the same time, due to the short static time and polarization effect, the voltage is difficult to accurately reflect the level of battery power. The original balancing strategy may have problems such as over-charging and even reverse balancing. In addition, due to the long-term performance degradation, the internal resistance, capacity, and charge efficiency of each monomer in the energy storage module will decay to varying degrees. This will further increase the complexity of balancing judgment and operation in power-type application scenarios. Summary of the invention

[0006] The present invention mainly solves the problem that the existing balancing method has poor adaptability to frequent and high-rate charging and discharging scenarios, is easily misled by the battery polarization voltage, and is prone to over-charging and even reverse balancing. It provides a balancing circuit and method for high-rate frequent charging and discharging energy storage modules.

[0007] The above technical problems of the present invention are mainly solved by the following technical solutions: a balancing circuit for a high-rate frequently charged and discharged energy storage module, the energy storage module includes energy storage monomers connected in series, including a control unit, a balancing capacitor corresponding to the energy storage monomer, the balancing capacitor is connected in parallel with the energy storage monomer, the high-voltage side and the low-voltage side of each balancing capacitor are connected respectively, and a selection switch group is connected between the balancing capacitors. The control unit sorts the energy storage monomers according to their voltages in the charging and discharging states, matches the charging and discharging sequences, and sequentially controls the opening and closing of the selection switches of the balancing capacitors corresponding to the energy storage monomers according to the matched sequence to perform balancing operations.

[0008] The present invention connects capacitors in parallel to energy storage cells to alleviate the high / low voltage phenomenon caused by abnormal polarization impedance during charging and discharging operation. At the same time, the symmetry of the impact of battery internal resistance on voltage under charging and discharging states is utilized to exclude or place energy storage cells with abnormal voltage caused by abnormal internal resistance in the balancing queue through sorting and matching to avoid interference with subsequent balancing processes. The circuit does not contain inductors and does not require high-frequency switch control signals. It has advantages in operating stability in relatively harsh communication environments.

[0009] As a preferred solution, the selection switch group includes a high-voltage selection switch connected to the high-voltage side of each balancing capacitor, and a low-voltage selection switch connected to the low-voltage side of each balancing capacitor.

[0010] The selection switch group is composed of a plurality of selection switches, which are preferably divided into high-voltage selection switches and low-voltage selection switches according to the connection relationship with the balancing capacitor. The high-voltage selection switch is connected to the high-voltage side of each balancing capacitor, and the low-voltage selection switch is connected to the low-voltage side of each balancing capacitor. The high-voltage selection switch and the low-voltage selection switch are respectively controlled and connected to the control unit.

[0011] As a preferred solution, an access switch is provided between each energy storage unit and the corresponding balancing capacitor.

[0012] An access switch is provided between each energy storage cell and its balancing capacitor. The access switch can be provided on the connection line between the energy storage cell and the low-voltage side of the balancing capacitor, or on the connection line between the energy storage cell and the high-voltage side of the balancing capacitor according to the demand. The access switches are respectively controlled to connect to the control unit, and the control unit controls the opening and closing of the access switch when it detects that the DC / DC or PCS sends a charge and discharge signal. The access switch is usually in a closed state, which can alleviate the false high voltage caused by the excessive impedance of the energy storage device to a certain extent. After the control unit detects the charge and discharge signal, it controls the disconnection of the access switch, and the balancing capacitor is then connected to the selection switch group, and the opening and closing are controlled according to the balancing signal of the control unit to control each balancing capacitor to perform a balancing operation.

[0013] In the above scheme, the energy storage unit, the balancing capacitor, the access switch, and the selection switch group together constitute a balancing circuit. The control unit controls the opening and closing of the balancing capacitor selection switch in sequence according to the matching order, and directly pairs the balancing capacitors in sequence to transfer the capacitors to each other.

[0014] Specifically, the control unit detects the charge and discharge signals, records the voltage and charge and discharge status of each energy storage unit, controls the disconnection of the access switch after a preset time, and sorts the energy storage units according to the voltage in the charge and discharge states, preferably in descending order of voltage in the charge state and in ascending order of voltage in the discharge state, pairs and matches the charge and discharge sequences in sequence, and connects the paired balancing capacitors in parallel in sequence by controlling the opening and closing of the selection switch group according to the matching sequence to perform a power balancing operation.

[0015] As a preferred solution, a transfer capacitor is connected between a connection point on the high voltage side and a connection point on the low voltage side of each balancing capacitor.

[0016] This scheme is the second implementation structure of the balancing circuit. By connecting a transfer capacitor between the high-voltage side connection point and the low-voltage side connection point of each balancing capacitor, a balancing circuit for transferring electricity is formed. The control unit controls the opening and closing of the balancing capacitor selection switch in sequence according to the matching order, and connects the balancing capacitor to the transfer capacitor in sequence to transfer the capacitance to each other.

[0017] Specifically, the control unit detects the charge and discharge signals, records the voltage and charge and discharge status of each energy storage unit, controls the disconnection of the access switch after a preset time, and sorts the energy storage units according to the voltage in the charge and discharge states, preferably in descending order of voltage in the charge state and in ascending order of voltage in the discharge state, cross-merges and matches the charge and discharge sequences, and controls the opening and closing of the selection switch group in sequence after matching to connect the equalizing capacitor corresponding to the energy storage unit with the transfer capacitor in turn to perform a power balancing operation.

[0018] Preferably, the transfer capacitor used in the balancing circuit can be replaced by a high-power battery. This solution can increase the amount of electricity transferred by the balancing capacitor during balancing, and improve the balancing efficiency to a certain extent. In particular, when the energy storage monomers such as batteries in the energy storage module are severely attenuated, it can effectively improve the circuit balancing effect.

[0019] As a preferred solution, the energy storage unit is combined with a balancing capacitor, and a switch group is selected to connect to form a balancing unit. The high-voltage side connection point and the low-voltage side connection point of the balancing capacitor serve as the output end and input end of the balancing unit respectively. The output end and input end of each balancing unit are connected respectively, and a secondary transfer capacitor is connected between the output end connection point and the input end connection point of each balancing circuit.

[0020] When the energy storage scale is large and the number of monomers is large, it can be divided into different balancing units. Preferably, each balancing unit is composed of an energy storage monomer, a balancing capacitor, a selection switch group, and an access switch connection. The high-voltage side connection point and the low-voltage side connection point of the balancing capacitor are used as the output and input ends of the balancing unit, respectively. Multiple balancing units are then connected in parallel to the secondary transfer capacitor to achieve cross-unit balancing. The energy storage monomer scales of the balancing units can be the same or different. Each balancing unit can perform power balancing independently, and the balancing process of each balancing unit is the same.

[0021] Preferably, a current-limiting resistor is provided between the equalizing capacitor and the high-voltage side connection point or the low-voltage side connection point; preferably, a current-limiting resistor is connected in series on one side of the transfer capacitor; preferably, a current-limiting resistor is connected in series on one side of the secondary transfer capacitor.

[0022] As a preferred embodiment, a current limiting resistor is connected in series between the low-voltage side and the low-voltage side connection point of the balancing capacitor, and the specific current limiting resistor is connected between the low-voltage selection switch and the low-voltage side connection point; and a current limiting resistor is connected in series on the high-voltage side or the low-voltage side of the transfer capacitor; in addition, a current limiting resistor can be connected in series on the high-voltage side or the low-voltage side of the secondary transfer capacitor. The current limiting resistor is set in the circuit to limit the amplitude of the current during the capacitor discharge period.

[0023] A method for balancing a high-rate frequently charged and discharged energy storage module, comprising the following steps: The energy storage module is in the charging and discharging state. After the set time, the charging and discharging voltage of each energy storage unit is recorded and the connection with the equalizing capacitor is disconnected; According to the charging and discharging states, the energy storage monomers are sorted by voltage respectively, and the charging and discharging sequences are matched; Select the matching energy storage monomers and corresponding balancing capacitors in sequence according to the matching order to balance the electricity; The balancing capacitor is reconnected to the energy storage monomer to balance the charge of the energy storage monomer.

[0024] The present invention can address the problem of high-frequency charging and discharging conditions, where static voltage is difficult to obtain due to the influence of battery polarization. At the same time, the test voltages of the charging and discharging states of the energy storage monomers are used to balance according to the charging and discharging voltage sorting. Specifically, the charging voltage is balanced from high to lower than the discharging state and from low to high in sequence. The opposite characteristics of polarization loss in the charging and discharging states are used to avoid the interference of impedance on voltage judgment to a certain extent. Energy storage monomers with abnormal voltage due to abnormal internal resistance are excluded or placed in the front of the balancing queue through sorting and matching to avoid interference with subsequent balancing processes. The present invention is limited to measuring the voltage after the energy storage monomer has been charged and discharged for a period of time. At this time, the state of the energy storage module is relatively the same, avoiding the problem of sudden changes in measurement data caused by instantaneous changes in working conditions during the sequential sampling of voltage. During the charging and discharging process, the energy storage monomer is connected to a balancing capacitor, which can alleviate the abnormal deviation of the charging and discharging voltage caused by excessive impedance of the energy storage monomer to a certain extent.

[0025] This solution records the charge and discharge voltage of each energy storage cell, and performs voltage acquisition by setting a voltage acquisition interface on the equalizing capacitor and a voltage sampling unit. The voltage of the equalizing capacitor is collected, and the voltage of the equalizing capacitor is used as the sampling voltage to improve the accuracy of voltage acquisition. When the equalizing capacitor is connected in parallel with the energy storage cell, its test value is basically consistent with the voltage of the energy storage cell. When the capacitor is disconnected from the energy storage cell and before the equalizing operation, the equalizing capacitor is basically fixed to the voltage of the energy storage cell at the moment of disconnection, avoiding the problem of sudden changes in voltage measurement data caused by instantaneous changes in the working conditions of the energy storage module.

[0026] As a preferred solution, the current charge and discharge state of the energy storage module is compared with the previous charge and discharge state. If the charge and discharge states are the same, the charge and discharge voltage of the energy storage unit is updated. If the charging and discharging states are opposite, the energy storage module is balanced.

[0027] During the operation of the method, each time a charge and discharge signal and a stop charge and discharge signal are received, it is a balancing process. After receiving the charge and discharge signal, the charge and discharge voltage of each energy storage monomer is recorded and the connection with the balancing capacitor is disconnected. The charge and discharge voltage includes the charge and discharge state and voltage information. The charge and discharge state of the current energy storage module is compared with the charge and discharge state of the previous balancing process. If the states are the same, only the charge and discharge voltage of the energy storage monomer is updated until the stop charge and discharge signal is received to complete a balancing process; if the states are opposite, the energy storage module is balanced, that is, the subsequent steps, and finally the stop charge and discharge signal is received to complete a balancing process.

[0028] As a preferred solution, in the charging state, the energy storage monomers are arranged in descending order according to voltage; In the discharge state, the energy storage cells are arranged in ascending order according to voltage.

[0029] Record and obtain the charging voltage of each energy storage monomer in the charging state, and the discharging voltage of each energy storage monomer in the discharging state. Arrange each energy storage monomer in descending order from high to low according to the charging voltage to obtain the charging sequence, and arrange each energy storage monomer in ascending order from low to high according to the discharging voltage to obtain the discharging sequence. Subsequently, the charging sequence and the discharging sequence are arranged in parallel, and the balancing capacitors corresponding to the energy storage monomers are selected in the order of the two sequences for matching.

[0030] As a preferred solution, the charging sequence and the discharging sequence are matched in pairs in sequence, and the matching equalizing capacitors are connected in parallel in sequence to balance the charge.

[0031] This solution selects two energy storage monomers for pairing in order, and forms a pairing sequence based on the pairing. Each pairing in the pairing sequence is a pair of paired energy storage monomers. According to the order of the pairing sequence, the balancing capacitors corresponding to the paired energy storage monomers are connected in parallel by controlling the opening and closing of the selection switch group. This continues for a certain period of time, and the charge is transferred between the two parallel balancing capacitors according to the voltage to achieve charge balance. And when the two paired energy storage monomers are the same energy storage monomer, the balancing operation of the pairing is skipped, and the next pairing is selected for the balancing operation. After all the paired corresponding balancing capacitors have completed the balancing in order, wait for the energy storage module to be charged and discharged, close the access switch, connect the balancing capacitor to the energy storage monomer, and the balancing capacitor charges and discharges the energy after this balancing with the energy storage monomer to complete the balancing operation of this energy storage monomer.

[0032] Compared with conventional balancing methods, this solution uses the symmetry of the impact of battery internal resistance on voltage under charging and discharging conditions to exclude energy storage cells with abnormal voltage caused by abnormal internal resistance from the balancing queue, avoiding their interference with subsequent balancing processes.

[0033] As a preferred solution, the charging sequence and the discharging sequence are cross-matched, and the corresponding balancing capacitors are connected to the transfer capacitors in sequence according to the matched sequence to perform power balancing.

[0034] This scheme cross-arranges and merges two sequences to form a merged sequence. The merged sequence can be in the order of discharge state first, that is, in the order of voltage "lowest discharge -> highest charge -> second lowest discharge -> second highest charge...", or in the order of voltage "highest charge -> lowest discharge -> second highest charge -> second lowest discharge...". The two sequences can be reasonably selected according to the current charge and discharge state, or the voltage distribution of the energy storage monomer at this time. According to the order of the merged sequence after matching, the switch group is controlled to open and close in turn to connect the balancing capacitor corresponding to the energy storage monomer in parallel with the transfer capacitor, and the charge is transferred between the balancing capacitor and the transfer capacitor according to the voltage to achieve power balance. In addition, the voltage of the transfer capacitor used to transfer power after the balance is completed can be used as the power representative of the current balancing unit, and further balanced with the transfer capacitor in other balancing units to realize a multi-level topological balancing circuit. In a balancing circuit with a multi-level topological structure, its hierarchical balancing structure is to divide a large-scale energy storage monomer into different balancing units, and the balancing process in each balancing unit is the same. After the balancing in the balancing unit is completed, the transfer capacitor can be individually balanced. At this time, the transfer capacitor is not connected to the energy storage module, so it does not affect the subsequent charging and discharging operations of the energy storage unit. After the transfer capacitor charge is balanced in each balancing unit, it will gradually affect the cable in the balancing capacitor, and finally achieve the effect of overall charge balance.

[0035] Compared with conventional balancing methods, this solution uses the symmetry of the impact of battery internal resistance on voltage under charging and discharging conditions to arrange the energy storage monomer with abnormal voltage caused by abnormal internal resistance at the front of the balancing queue, so that it only exchanges electricity with the steady-state transfer capacitor to avoid its interference with the subsequent balancing process. In an alternating charging and discharging working environment, the voltage of the energy storage monomer with abnormal internal resistance will be higher or lower accordingly, and it will charge and discharge alternately with the transfer capacitor during balancing, and the total amount of electricity will change in a limited range, forming a dynamic electricity stability.

[0036] Therefore, the advantages of the present invention are: 1. In view of the problem that static voltage is difficult to obtain under high-frequency charging and discharging conditions due to the influence of battery polarization, the test voltage of the charging and discharging states of the energy storage monomer is used at the same time. The charging voltage is balanced from high to low and the discharging voltage is balanced from low to high. The opposite characteristics of polarization loss in the charging and discharging states are used to avoid the interference of impedance on voltage judgment to a certain extent.

[0037] 2. The circuit does not contain inductors and does not require high-frequency switching control signals. It has advantages in operating stability in relatively harsh communication environments.

[0038] 3. Measure the voltage after the energy storage unit has been charged and discharged for a period of time. At this time, the state of the energy storage module is relatively the same, avoiding the problem of sudden changes in measurement data caused by instantaneous changes in working conditions during sequential voltage sampling.

[0039] 4. During the charging and discharging process, the energy storage monomer is connected to a balancing capacitor, which can alleviate the abnormal deviation of the charging and discharging voltage caused by the excessive impedance of the energy storage monomer to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the first structure of the equalization circuit in the present invention.

[0041] Figure 2 This is a second structural schematic diagram of the equalizing circuit in the present invention.

[0042] Figure 3 It is a schematic diagram of the multi-layer topology circuit structure based on the first equalization circuit in the present invention.

[0043] Figure 4 It is a schematic diagram of the multi-layer topology circuit structure based on the second equalization circuit in the present invention.

[0044] Figure 5 It is a flow chart of the first equalization circuit equalization method in the present invention.

[0045] Figure 6 It is a flow chart of the second equalization circuit equalization method in the present invention. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0047] Embodiment 1: The present embodiment provides a balancing circuit for a high-rate frequently charged and discharged energy storage module, the energy storage module includes a plurality of energy storage cells connected in series, the balancing circuit structure includes a control unit, balancing capacitors corresponding to the energy storage cells, the balancing capacitors are connected in parallel with the energy storage cells, the high-voltage side and the low-voltage side of each balancing capacitor are connected respectively, and a selection switch group is connected between the balancing capacitors; The control unit sorts the voltages of the energy storage monomers in the charging and discharging states, matches the charging and discharging sequences, and sequentially controls the opening and closing of the selection switches of the balancing capacitors corresponding to the energy storage monomers according to the matched sequence to perform balancing operations.

[0048] The present invention connects capacitors in parallel to energy storage cells to alleviate the high / low voltage phenomenon caused by abnormal polarization impedance during charging and discharging operation. At the same time, the symmetry of the impact of battery internal resistance on voltage under charging and discharging states is utilized to exclude or place energy storage cells with abnormal voltage caused by abnormal internal resistance in the balancing queue through sorting and matching to avoid interference with subsequent balancing processes. The circuit does not contain inductors and does not require high-frequency switch control signals. It has advantages in operating stability in relatively harsh communication environments.

[0049] According to the difference in the way of transferring electricity in the balancing capacitor, two types of circuit structures can be proposed, specifically: 1. Direct pairing balancing circuit in which the electricity in the balancing capacitor is directly transferred in pairs; 2. Transfer electricity balancing circuit in which the balancing capacitor is transferred in turn with a certain transfer capacitor. The balancing circuit in this embodiment is a direct pairing balancing circuit, such as Figure 1 As shown, the energy storage module includes energy storage cells (B1-Bn) connected in series, and preferably the energy storage cells are batteries. The balancing circuit includes balancing capacitors (C1-Cn) corresponding to the number of energy storage cells, and the corresponding balancing capacitors are connected in parallel to the energy storage cells. The high-voltage side of each balancing capacitor is connected to the high-voltage side bus, connected together through the high-voltage side bus, and the low-voltage side of each balancing capacitor is connected to the low-voltage side bus, connected together through the low-voltage side bus. An access switch SP is provided on the connection line between the low-voltage side of the balancing capacitor and the corresponding energy storage cell, and the control end of each access switch is connected to the control unit and is controlled to open and close by the control unit. A selection switch group is connected between the balancing capacitors, and preferably, the selection switch group includes a high-voltage selection switch SH and a low-voltage selection switch SL corresponding to each balancing capacitor, the high-voltage selection switch is connected between the high-voltage side of the balancing capacitor and the high-voltage side bus, and the low-voltage selection switch is connected between the low-voltage side of the balancing capacitor and the low-voltage side bus. The control ends of the high-voltage selection switch and the low-voltage selection switch are both connected to the control unit and are controlled to open and close by the control unit. A current limiting resistor Rl is connected between the low voltage selector switch and the low voltage side bus.

[0050] In the balancing circuit, the access switch SP controls the connection and disconnection between the energy storage monomer and the balancing capacitor. The access switch is controlled by the control unit. The control unit controls the opening and closing of the access switch when it detects that the DC / DC or PCS sends a charge and discharge signal. The access switch is usually in a closed state, which can alleviate the false high voltage caused by the excessive impedance of the energy storage device to a certain extent. The specific control process of the access switch is: when the control unit detects the charge and discharge signal, it controls the disconnection of the access switch, the energy storage monomer is disconnected from the balancing capacitor, and the balancing capacitor is then connected to the selection switch group. The opening and closing is controlled according to the balancing signal of the control unit to control each balancing capacitor to perform a balancing operation. When the control unit detects the stop charge and discharge signal, it controls the closing of the access switch, and the balancing capacitor is connected to the energy storage monomer.

[0051] As a preferred solution, a current limiting resistor R1 is connected between the low voltage selection switch and the low voltage side bus to limit the amplitude of the current during capacitor discharge.

[0052] The control unit can adopt BMS, which receives the charge and discharge signals sent by DC / DC or PCS, and controls the opening and closing of the access switch according to the charge and discharge signals. The control unit collects the charge and discharge voltages of each energy storage cell, and connects the collection interface to the control unit by setting a voltage collection interface on the equalizing capacitor. The voltage of the equalizing capacitor is collected, and the voltage of the equalizing capacitor is used as the sampling voltage to improve the accuracy of voltage collection. When the equalizing capacitor is connected in parallel with the energy storage cell, its test value is basically consistent with the voltage of the energy storage cell. When the capacitor is disconnected from the energy storage cell and before the equalizing operation, the equalizing capacitor is basically fixed to the voltage of the energy storage cell at the moment of disconnection, avoiding the problem of sudden changes in voltage measurement data caused by instantaneous changes in the working conditions of the energy storage module. The collected charge and discharge voltage includes charge and discharge status and voltage information. The control unit records the charge and discharge parameters of the energy storage cell during each equalization process, and stores the charge and discharge parameters of this time as historical parameters. In the current balancing process, the control unit compares the currently recorded charge and discharge state of the energy storage module with the charge and discharge state of the energy storage module recorded in the previous balancing process, that is, the historical parameters. If the charge and discharge states of the two times are the same, the historical parameters are updated with the current charge and discharge voltage of the energy storage module, and the balancing process ends. If the charge and discharge states of the two times are opposite, the energy storage module is balanced, and finally a stop charge and discharge signal is received to complete a balancing process. The balancing process is specifically that the control unit controls the disconnection of the access switch after a preset time, sorts the energy storage monomers according to the voltage under the charging and discharging states, preferably arranges them in descending order according to the voltage under the charging state, and arranges them in ascending order according to the voltage under the discharging state, and matches the charging and discharging sequences in sequence, and controls the opening and closing of the selection switch group according to the matching sequence to connect the paired balancing capacitors in parallel in turn to balance the electricity.

[0053] This embodiment discloses a balancing method for high-rate frequent charging and discharging energy storage modules, such as Figure 5 As shown, the following steps are included: S1. The energy storage module is in the charging and discharging state. After the set time, the charging and discharging voltage of each energy storage unit is recorded and the connection with the equalizing capacitor is disconnected.

[0054] As a preferred solution of this scheme, when the energy storage module is in the charge and discharge state, the access switch is closed, and the energy storage monomer is connected to the equalizing capacitor. After receiving the charge and discharge signal sent by the DC / DC or PCS, the control unit starts the countdown, and after T1 seconds, it records the voltage and charge and discharge state of each energy storage monomer, and controls the access switch to be disconnected to disconnect the energy storage monomer from the equalizing capacitor.

[0055] S2. Determine whether there is a record of the last charge and discharge voltage of the energy storage unit. If yes, proceed to the next step; if no, update the currently recorded energy storage cell voltage with the last energy storage cell charge and discharge voltage, and proceed to step S5.

[0056] S3. Determine whether the current energy storage monomer charge and discharge state is opposite to the previous energy storage monomer charge and discharge state. If yes, proceed to the next step; if no, update the currently recorded energy storage cell voltage with the last energy storage cell voltage, and proceed to step S5.

[0057] The current charge and discharge state of the energy storage module is compared with the charge and discharge state of the previous balancing process. If the states are the same, only the charge and discharge voltage of the energy storage monomer is updated until a stop charge and discharge signal is received to complete a balancing process; if the states are opposite, the energy storage module is balanced.

[0058] S4. According to the charging and discharging states, the energy storage cells are sorted by voltage respectively, and the charging and discharging sequences are matched.

[0059] S41. In the charging state, the energy storage monomers are arranged in descending order according to the voltage to obtain a charging sequence; In the discharge state, the energy storage cells are arranged in ascending order according to the voltage to obtain a discharge sequence.

[0060] S42. Match the charging sequence and the discharging sequence in pairs in order, and sequentially connect the matching balancing capacitors in parallel to balance the charge.

[0061] The two sequences select two energy storage monomers for pairing in order, and form a pairing sequence according to the pairing. Each pairing in the pairing sequence is a pair of paired energy storage monomers. According to the order of the pairing sequence, the balancing capacitors corresponding to the paired energy storage monomers are connected in parallel by controlling the opening and closing of the selection switch group, which lasts for T2 time. The charge is transferred between the two parallel balancing capacitors according to the voltage to achieve charge balance. And when the two paired energy storage monomers are the same energy storage monomers, the balancing operation of the pairing is skipped, and the next pairing is selected for balancing operation. Through the above balancing operation, the balancing operation is completed until all paired balancing capacitors complete the balancing operation.

[0062] S5. The balancing capacitor is reconnected to the energy storage unit to balance the charge of the energy storage unit.

[0063] S51. After receiving the stop charging and discharging signal sent by the DC / DC or PCS, control the access switch to connect and reconnect the energy storage unit to the balancing capacitor.

[0064] S52. The balancing capacitor charges and discharges the balanced electric quantity with the energy storage monomer to balance the energy storage monomer, thus completing the current balancing process.

[0065] The following uses an example to illustrate the balancing method of this embodiment. The energy storage module is used for short-term and frequent electric energy recovery, with a charge and discharge duration of 10 - 20 s and an interval time of about 20 s. Affected by the charge and discharge conditions, its actual measured voltage fluctuates within the range of ±6% of the static voltage. At this time, when using a conventional balancing circuit, it is difficult to accurately evaluate the remaining power due to the influence of the monomer voltage fluctuation, which further affects the subsequent balancing operation.

[0066] This example takes a high-power energy storage battery with a group of 5 cells as an example. Five single cells B1 - B5 construct an energy storage module, which are respectively connected in parallel with balancing capacitors C1 - C5. The on-off between the single cell and the balancing capacitor is controlled by an NMOS transistor. The two ends of the balancing capacitor are connected in parallel to the high-voltage side and low-voltage side buses, and the specific parallel situation is controlled by an NMOS transistor. The opening and closing of the NMOS transistor are controlled by a dedicated control chip. Based on the charge and discharge signals of the DC - DC / PCS and the voltage sorting of the charge and discharge states, a suitable balancing process is calculated and the connection situation of the circuit is adjusted.

[0067] When the energy storage module enters the charge / discharge condition, after a period of time, the battery voltage is recorded, and the connection between the capacitors C1 - C5 and the battery is disconnected. Comparing the data records, this example takes the situation that needs to perform a balancing operation as an example, and sorts the voltages in the charge / discharge condition.

[0068] During the operation of the module, the impedance of battery B3 is too high, and at the same time, the power of battery B2 is too high. During its charging process, the voltage sorting is "B3 > B2 > B1 ≈ B4 ≈ B5"; during the discharging process, the measured voltage is "B3 < B1 ≈ B4 ≈ B5 < B2". Then during the start of balancing, the balancing capacitors are paired and conducted in sequence according to "C3 - C3, C2 - C1, C1 - C4, C4 - C5, C5 - C2". The final result is that C2 discharges to C1, C4, and C5, while C3 does not participate in the balancing process, effectively avoiding the influence of polarization impedance on the balancing process.

[0069] Compared with the conventional balancing method and circuit, the circuit used in this embodiment, because it is provided with parallel capacitors, can alleviate the phenomenon of too high or too low voltage caused by abnormal polarization impedance during the charge and discharge operation. At the same time, by using the symmetry of the influence of the battery internal resistance on the voltage in the charging and discharging states, the single cells with abnormal voltage caused by abnormal internal resistance are excluded from the balancing queue to avoid their interference with the subsequent balancing process. In addition, because the circuit does not contain an inductor and does not require a high-frequency switching control signal, it also has certain advantages in operation stability in a relatively harsh communication environment.

[0070] Embodiment 2: This embodiment discloses a balancing circuit for high-rate frequent charge and discharge energy storage modules. When the energy storage scale is large and the number of cells is large, it is necessary to divide it into different balancing units. After the balancing is completed in the balancing unit, further balancing operations are performed between the balancing units, thus forming a multi-level topological balancing circuit. Figure 3 As shown, the specific structure is: The balancing unit adopts the balancing circuit directly paired in Example 1, and the high-voltage side connection point and the low-voltage side connection point of the balancing capacitor are respectively used as the output end and the input end of the balancing unit, and the output end and the input end of each balancing unit are respectively connected, and a secondary transfer capacitor Ct2 is connected between the output end connection point and the input end connection point of each balancing unit. A secondary selection switch is provided between the output end of each balancing unit and the connection of the secondary transfer capacitor. A current-limiting resistor is connected in series at one end of the secondary transfer capacitor.

[0071] This embodiment takes two balancing units as an example, the energy storage modules of the balancing units are connected in series, the output end of the first balancing unit is connected to the high voltage side of the secondary transfer capacitor through the secondary selection switch Sp1, and the input end is connected to the low voltage side of the secondary transfer capacitor. The output end of the second balancing unit is connected to the high voltage side of the secondary transfer capacitor through the secondary selection switch Sp2, and the input end is connected to the low voltage side of the secondary transfer capacitor.

[0072] The balancing process in each balancing unit is the same. After the balancing in the balancing unit is completed, the last group of interconnected balancing capacitors is used to connect to the secondary transfer capacitors. After all balancing units are balanced, the control unit controls the opening and closing of the secondary selection switch to connect the balancing units to the secondary transfer capacitors in turn to balance the electricity and finally complete the overall electricity balance.

[0073] Embodiment 3: This embodiment discloses a second implementation structure of a balancing circuit for a high-rate frequently charged and discharged energy storage module, the specific structure includes a control unit, a balancing capacitor corresponding to the energy storage monomer, the balancing capacitor is connected in parallel with the energy storage monomer, the high-voltage side and the low-voltage side of each balancing capacitor are connected respectively, and a selection switch group is connected between the balancing capacitors; The control unit sorts the voltages of the energy storage monomers in the charging and discharging states, matches the charging and discharging sequences, and sequentially controls the opening and closing of the selection switches of the balancing capacitors corresponding to the energy storage monomers according to the matched sequence to perform balancing operations.

[0074] The balancing circuit of this embodiment adopts a transfer power balancing circuit, such as Figure 2As shown, the balancing circuit of this embodiment is a variation of the balancing circuit in Embodiment 1, and its principle is the same, with the addition of a transfer capacitor, and the charge balance between the balancing capacitors is achieved through the transfer capacitor. The specific structure is that the energy storage module includes energy storage monomers (B1-Bn) connected in series, and the energy storage monomers are preferably batteries. The balancing circuit includes balancing capacitors (C1-Cn) corresponding to the number of energy storage monomers, and the corresponding balancing capacitors are respectively connected in parallel to the energy storage monomers, and the balancing capacitors are connected in series. The two ends of the balancing capacitor series circuit and the connection points between the balancing capacitors are respectively connected to the high-voltage side bus and the low-voltage side bus in an intermittent manner. The high-voltage side bus is connected in parallel with the low-voltage side bus, and a transfer capacitor Ct is connected between the two end points of the high-voltage side bus, and one end of the transfer capacitor is connected in series with a current-limiting resistor. An access switch SP is provided between the positive electrode of the energy storage monomer and the high-voltage side connection of the balancing capacitor, and an access switch is provided between the negative electrode of the last energy storage monomer and the low-voltage side of the corresponding balancing capacitor. A high-voltage selection switch SH is connected between the positive terminal of the high-voltage bus, the positive terminal of the low-voltage bus and the transfer capacitor, and a low-voltage selection switch SL is connected between the negative terminal of the low-voltage bus, the negative terminal of the low-voltage bus and the transfer capacitor. A selection switch SS is connected between the high-voltage side of the balancing capacitor and the high-voltage bus and the low-voltage bus, and a selection switch is connected between the last balancing unit and the low-voltage bus.

[0075] In the balancing circuit, the access switch SP controls the connection and disconnection between the energy storage monomer and the balancing capacitor. The access switch is controlled by the control unit. The control unit controls the opening and closing of the access switch when it detects that the DC / DC or PCS sends a charge and discharge signal. The access switch is usually in a closed state, which can alleviate the false high voltage caused by the excessive impedance of the energy storage device to a certain extent. The specific control process of the access switch is: when the control unit detects the charge and discharge signal, it controls the disconnection of the access switch, the energy storage monomer is disconnected from the balancing capacitor, and the balancing capacitor is then connected to the selection switch group. The opening and closing is controlled according to the balancing signal of the control unit to control each balancing capacitor to perform a balancing operation. When the control unit detects the stop charge and discharge signal, it controls the closing of the access switch, and the balancing capacitor is connected to the energy storage monomer.

[0076] As a preferred solution, a current limiting resistor R1 is connected between the low voltage selection switch and the low voltage side bus to limit the amplitude of the current during capacitor discharge.

[0077] The control unit can adopt BMS, which receives the charge and discharge signals sent by DC / DC or PCS, and controls the opening and closing of the access switch according to the charge and discharge signals. The control unit collects the charge and discharge voltages of each energy storage cell, and connects the collection interface to the control unit by setting a voltage collection interface on the equalizing capacitor. The voltage of the equalizing capacitor is collected, and the voltage of the equalizing capacitor is used as the sampling voltage to improve the accuracy of voltage collection. When the equalizing capacitor is connected in parallel with the energy storage cell, its test value is basically consistent with the voltage of the energy storage cell. When the capacitor is disconnected from the energy storage cell and before the equalizing operation, the equalizing capacitor is basically fixed to the voltage of the energy storage cell at the moment of disconnection, avoiding the problem of sudden changes in voltage measurement data caused by instantaneous changes in the working conditions of the energy storage module. The collected charge and discharge voltage includes charge and discharge status and voltage information. The control unit records the charge and discharge parameters of the energy storage cell during each equalization process, and stores the charge and discharge parameters of this time as historical parameters. In the current balancing process, the control unit compares the currently recorded charge and discharge state of the energy storage module with the charge and discharge state of the energy storage module recorded in the previous balancing process, that is, the historical parameters. If the charge and discharge states of the two times are the same, the historical parameters are updated with the current charge and discharge voltage of the energy storage module, and the balancing process ends. If the charge and discharge states of the two times are opposite, the energy storage module is balanced, and finally a stop charge and discharge signal is received to complete a balancing process. The balancing process is specifically that the control unit controls the disconnection of the access switch after a preset time, sorts the energy storage monomers according to the voltage under the charging and discharging states, preferably arranges them in descending order according to the voltage under the charging state, and arranges them in ascending order according to the voltage under the discharging state, and matches the charging and discharging sequences in sequence, and controls the opening and closing of the selection switch group according to the matching sequence to connect the paired balancing capacitors in parallel in turn to balance the electricity.

[0078] This embodiment discloses a balancing method for high-rate frequent charging and discharging energy storage modules, such as Figure 6 As shown, the following steps are included: S1. The energy storage module is in the charging and discharging state. After the set time, the charging and discharging voltage of each energy storage unit is recorded and the connection with the equalizing capacitor is disconnected.

[0079] As a preferred solution of this scheme, when the energy storage module is in the charging and discharging state, the access switch is closed, and the energy storage monomer is connected to the balancing capacitor. After receiving the charging and discharging signal sent by the DC / DC or PCS, the control unit starts the countdown, and after T1 seconds, it records the voltage and charging and discharging state of each energy storage monomer, and controls the access switch to be disconnected to disconnect the energy storage monomer from the balancing capacitor.

[0080] S2. Determine whether there is a record of the last charge and discharge voltage of the energy storage unit. If yes, proceed to the next step; if no, update the currently recorded energy storage cell voltage with the last energy storage cell charge and discharge voltage, and proceed to step S5.

[0081] S3. Determine whether the current energy storage monomer charge and discharge state is opposite to the previous energy storage monomer charge and discharge state. If yes, proceed to the next step; if no, update the currently recorded energy storage cell voltage with the last energy storage cell voltage, and proceed to step S5.

[0082] The current charge and discharge state of the energy storage module is compared with the charge and discharge state of the previous balancing process. If the states are the same, only the charge and discharge voltage of the energy storage monomer is updated until a stop charge and discharge signal is received to complete a balancing process; if the states are opposite, the energy storage module is balanced.

[0083] S4. According to the charging and discharging states, the energy storage cells are sorted by voltage respectively, and the charging and discharging sequences are matched.

[0084] S41. In the charging state, the energy storage monomers are arranged in descending order according to the voltage to obtain a charging sequence; In the discharge state, the energy storage cells are arranged in ascending order according to the voltage to obtain a discharge sequence.

[0085] S42. Cross-match the charging sequence and the discharging sequence in order, and connect the corresponding balancing capacitors to the transfer capacitors in order according to the matched sequence to balance the charge.

[0086] The two sequences are cross-arranged and merged to form a merged sequence. The merged sequence can be in the order of discharge state first, that is, in the order of voltage "lowest discharge -> highest charge -> second lowest discharge -> second highest charge...", or in the order of voltage "highest charge -> lowest discharge -> second highest charge -> second lowest discharge...". The two sequences can be reasonably selected according to the current charge and discharge state, or the voltage distribution of the energy storage monomer at this time. According to the order of the matched merged sequence, the switch group is controlled to open and close in turn to connect the balancing capacitor corresponding to the energy storage monomer in parallel with the transfer capacitor, and the charge is transferred between the balancing capacitor and the transfer capacitor according to the voltage to achieve charge balancing.

[0087] S5. The balancing capacitor is reconnected to the energy storage unit to balance the charge of the energy storage unit.

[0088] S51. After receiving the stop charging and discharging signal sent by the DC / DC or PCS, control the access switch to connect and reconnect the energy storage unit to the balancing capacitor.

[0089] S52. The balancing capacitor charges and discharges the balanced electric quantity with the energy storage monomer to balance the energy storage monomer, thus completing the current balancing process.

[0090] The following uses an example to illustrate the balancing method of this embodiment. The energy storage module is used for short-term and frequent electric energy recovery, with a charge and discharge duration of 10 - 20 s and an interval time of about 20 s. Affected by the charge and discharge conditions, its actual measured voltage fluctuates within the range of ±6% of the static voltage. At this time, when using a conventional balancing circuit, it is difficult to accurately evaluate the remaining power due to the influence of the monomer voltage fluctuation, which further affects the subsequent balancing operation.

[0091] This example takes a high-power energy storage battery with a group of 5 cells as an example. Five single cells B1 - B5 construct an energy storage module, which are respectively connected in parallel with balancing capacitors C1 - C5. The on-off between the single cell and the balancing capacitor is controlled by an NMOS transistor. The balancing capacitors C1 - C5 are respectively connected in parallel with a transfer capacitor Ct1, and the specific parallel situation is controlled by an NMOS transistor. The opening and closing of the NMOS transistor are controlled by a dedicated control chip. Based on the charge and discharge signals of the DC - DC / PCS and the voltage sorting of the charge and discharge states, a suitable balancing process is calculated, and the connection situation of the circuit is adjusted.

[0092] When the energy storage module enters the charge / discharge condition, the battery voltage is recorded after a period of time, and the connection between the capacitors C1 - C5 and the battery is disconnected. Comparing the data records, this example takes the situation that a balancing operation is required as an example, and the voltage sorting under the charge / discharge condition. The charging voltage records are sorted from high to low, while the discharging voltage records are sorted from low to high, and then cross-merged and arranged to form a merged sequence. In particular, since the Coulomb efficiency of this high-power battery decreases significantly with the increase of impedance, therefore, using the order of "the lowest discharging voltage -> the highest charging voltage -> the second lowest discharging voltage -> the second highest charging voltage...", the lost power caused by side reactions can be supplemented to a certain extent, and the balancing effect will be improved.

[0093] During the operation of the module, the impedance of battery B3 is on the high side, and at the same time, the power of battery B2 is on the high side. During its charging process, the voltage sorting is "B3 > B2 > B1 ≈ B4 ≈ B5"; during the discharging process, the measured voltage is "B3 < B1 ≈ B4 ≈ B5 < B2". The above two sequences are cross-merged and arranged in order to form the final merged sequence "B3 - B3 - B1 - B2 - B4 - B1 - B5 - B4 - B2 - B5". At this time, during the charge and discharge processes, the balancing capacitor C3 is first connected to the transfer capacitor. The power lost during the balancing process during charging will be compensated during the discharging process, which can relieve the influence of the balancing operation caused by too high impedance to a certain extent. In the remaining balancing operations, it is the process of the balancing capacitor C2 discharging to the remaining batteries. After the balancing operation is completed, the capacitor is re-connected in parallel with the battery, and finally the overall balancing of the energy storage module is realized.

[0094] Compared with conventional balancing methods and circuits, the method used in this embodiment can alleviate the abnormal voltage rise / drop phenomenon caused by polarization impedance during charging and discharging operations. At the same time, the symmetry of the impact of battery internal resistance on voltage under charging and discharging states is utilized to arrange the voltage abnormal monomers caused by abnormal internal resistance at the front of the balancing queue, so that they only exchange electricity with the steady-state transfer capacitor to avoid their influence on the subsequent balancing process. In a working environment where charging and discharging alternate, the voltage of the monomer with abnormal internal resistance will be correspondingly high or low, and it will alternate with the charging and discharging of the transfer capacitor during balancing, and the total amount of electricity will change in a limited range, forming a dynamic electricity stability.

[0095] Embodiment 4: This embodiment discloses a balancing circuit for high-rate frequent charge and discharge energy storage modules. When the energy storage scale is large and the number of cells is large, it is necessary to divide it into different balancing units. After the balancing is completed in the balancing unit, further balancing operations are performed between the balancing units, thus forming a multi-level topological balancing circuit. Figure 4 As shown, the specific structure is: The balancing unit adopts the transfer power balancing circuit in Example 3, wherein the positive terminal of the high-voltage side bus serves as the output terminal of the balancing unit, and the negative terminal of the high-voltage side bus serves as the input terminal of the balancing unit. The output terminals and input terminals of each balancing unit are connected respectively, and a secondary transfer capacitor Ct2 is connected between the connection point of the output terminal and the connection point of the input terminal of each balancing unit. A secondary selection switch is provided between the connection of the output terminal of each balancing unit and the secondary transfer capacitor. A current-limiting resistor is connected in series at one end of the secondary transfer capacitor.

[0096] This embodiment takes two balancing units as an example, the energy storage modules of the balancing units are connected in series, the output end of the first balancing unit is connected to the high voltage side of the secondary transfer capacitor through the secondary selection switch Sp1, and the input end is connected to the low voltage side of the secondary transfer capacitor. The output end of the second balancing unit is connected to the high voltage side of the secondary transfer capacitor through the secondary selection switch Sp2, and the input end is connected to the low voltage side of the secondary transfer capacitor.

[0097] The balancing process in each balancing unit is the same. After the balancing in the balancing unit is completed, the voltage of the transfer capacitor is used as the power representative of the current balancing unit and is connected to the secondary transfer capacitor for power balancing. Each balancing unit is connected to the secondary transfer capacitor in turn, and finally power balancing is achieved for multiple balancing units.

[0098] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A balancing circuit for a high-rate frequent charge and discharge energy storage module, the energy storage module comprising energy storage monomers connected in series, characterized in that: It includes a control unit, a balancing capacitor corresponding to the energy storage monomer, the balancing capacitor is connected in parallel with the energy storage monomer, the high-voltage side and the low-voltage side of each balancing capacitor are connected respectively, and a selection switch group is connected between the balancing capacitors. The control unit sorts the voltages of the energy storage monomers in the charging and discharging states, matches the charging and discharging sequences, and sequentially controls the opening and closing of the selection switches of the balancing capacitors corresponding to the energy storage monomers according to the matched sequence to perform balancing operations.

2. The equalizing circuit for high-rate frequent charge and discharge energy storage module according to claim 1, characterized in that: The selection switch group includes a high-voltage selection switch connected to the high-voltage side of each balancing capacitor, and a low-voltage selection switch connected to the low-voltage side of each balancing capacitor.

3. The equalizing circuit for high-rate frequent charge and discharge energy storage module according to claim 2, characterized in that: An access switch is provided between each energy storage unit and the corresponding balancing capacitor.

4. The equalizing circuit for high-rate frequent charge and discharge energy storage module according to claim 3 is characterized in that: A transfer capacitor is connected between a connection point on the high voltage side and a connection point on the low voltage side of each balancing capacitor.

5. A balancing circuit for a high-rate frequent charge and discharge energy storage module according to claim 3 or 4, characterized in that: The energy storage unit is combined with a balancing capacitor, and a switch group is selected to connect to form a balancing unit. The high-voltage side connection point and the low-voltage side connection point of the balancing capacitor are used as the output end and input end of the balancing unit respectively. The output end and input end of each balancing unit are connected respectively, and a secondary transfer capacitor is connected between the output end connection point and the input end connection point of each balancing circuit.

6. A method for balancing a high-rate frequently charged and discharged energy storage module, using the circuit described in any one of claims 1 to 5, characterized in that: The following steps are involved: The energy storage module is in the charging and discharging state. After the set time, the charging and discharging voltage of each energy storage unit is recorded and the connection with the equalizing capacitor is disconnected; According to the charging and discharging states, the energy storage monomers are sorted by voltage respectively, and the charging and discharging sequences are matched; Select the matching energy storage monomers and corresponding balancing capacitors in sequence according to the matching order to balance the electricity; The balancing capacitor is reconnected to the energy storage monomer to balance the charge of the energy storage monomer.

7. A balancing method for high-rate frequent charge and discharge energy storage modules according to claim 6, characterized in that: Compare the current charge and discharge status of the energy storage module with the previous charge and discharge status. If the charge and discharge states are the same, the charge and discharge voltage of the energy storage unit is updated. If the charging and discharging states are opposite, the energy storage module is balanced.

8. A balancing method for high-rate frequent charge and discharge energy storage modules according to claim 6 or 7, characterized in that: In the charging state, the energy storage cells are arranged in descending order according to voltage; In the discharge state, the energy storage cells are arranged in ascending order according to voltage.

9. A balancing method for high-rate frequent charge and discharge energy storage modules according to claim 8, characterized in that: The charging sequence and the discharging sequence are matched in pairs in sequence, and the matching equalizing capacitors are connected in parallel in sequence to balance the charge.

10. A balancing method for a high-rate frequent charge and discharge energy storage module according to claim 8, characterized in that: The charging sequence and the discharging sequence are cross-matched and merged, and the corresponding balancing capacitors are connected to the transfer capacitors in sequence according to the matched sequence to balance the charge.

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