Multi-mode fused active equalizer for power battery

Abstract

The invention discloses a multi-mode fused active equalizer for a power battery, which is used for transmitting the energy of an overcharge battery monomer to a battery string, transmitting the energy of the battery string to an under-charge battery monomer, or directly transmitting the energy of the overcharge battery monomer to the under-charge battery monomer, so that the SOC (State of Charge) consistency of a battery cluster is realized through active equalization. The battery string is connected with the detection circuit, the detection circuit is used for monitoring the open-circuit voltage and the charge state of the battery, the detection circuit is connected with the microprocessor, the microprocessor is connected with the bidirectional converter through the driving circuit, and the bidirectional converter is connected with the battery string through the bidirectional switch array; and when the charge states of the batteries are inconsistent, different bidirectional switch arrays are formed to communicate the target battery with the bidirectional converter, so that equalization from the battery monomers to the battery strings, equalization from the battery strings to the battery monomers or equalization from local battery monomers to the battery monomers is realized. According to the invention, the equalization speed and efficiency of the power battery system under complex over-charge and under-charge conditions are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of battery energy storage and power electronics, and in particular to a multi-mode integrated power battery active equalizer. Background Art

[0002] Power batteries are the power source and key link of electric vehicles. Strengthening breakthroughs and innovations in core power battery technologies can enhance the market competitiveness of new energy electric vehicles and promote the low-carbon and sustainable development of the automotive industry.

[0003] As one of the core technologies of power batteries, balancing technology can reduce the inconsistency between battery cells caused by differences in status during production and use. By making the battery module reach a more balanced state, it can significantly improve the performance, life and cruising range of power batteries and reduce safety hazards caused by differences in battery cell performance.

[0004] The active balancing technology of power batteries based on bidirectional converters transfers energy from high SOC (State of Charge) batteries to low SOC batteries in a high-speed and high-efficiency manner by applying the principles of power electronics, achieving consistency between battery modules and battery cells, thereby effectively meeting the safety and reliable application requirements of power battery modules with high string counts and large capacity. Taking battery cells as the balancing target, active balancing modes can be divided into AC2C (Adjacent Cell to Cell), S2C (String to Cell), C2S (Cell to String), AC2AC (Any Cell to Any Cell), etc. Among them, the AC2C mode has the disadvantages of repeated balancing paths and slow balancing speed; the S2C, C2S and AC2AC modes can achieve good balancing effects between battery cells and battery strings or between battery cells and battery cells, but limited by the active balancing structure, the existing active balancing technology cannot achieve the above three balancing modes at the same time. The power battery system is a complex and strongly nonlinear system. When inconsistency occurs, the following three situations may exist: ① Multiple battery cells are overcharged, ② Multiple battery cells are undercharged, and ③ Multiple battery cells are overcharged and undercharged at the same time. At this time, for situation ①, since there are no undercharged battery cells in the system, the active balancer that can only implement the AC2AC mode cannot locate and establish an energy transmission loop with the undercharged cells, and the balancing mode fails; for situation ②, since there are no overcharged battery cells in the system, the active balancer that can only implement the AC2AC mode cannot form and establish a transmission loop provided by the overcharged cells, and the balancing mode fails; for situation ③, since there are overcharged battery cells and undercharged battery cells in the system at the same time, the active balancer that can only implement the S2C and C2S modes needs to transfer energy from the overcharged battery cells to the battery string first, and then from the battery string to the undercharged battery cells, which will reduce the balancing speed and cause safety hazards.

[0005] In order to solve the above problems, people have been seeking an ideal power battery active balancing technology solution.

[0006] In CN 118381138 A, the bidirectional converter connected between the first battery and the second battery is controlled to be in the target working mode to maintain the charge balance between the first battery and the second battery. The application scenario of this patent is low-power portable devices such as mobile phones. There are only two batteries in the system. The method proposed in this patent can easily achieve the charge balance between the two batteries. However, the vehicle-mounted power battery system is composed of hundreds or thousands of battery cells. At this time, the method proposed in this patent cannot be used to achieve the charge balance of many battery cells, and the safety hazard caused by inconsistent battery SOC cannot be solved.

[0007] CN 103199589 A proposes a modular fast equalization circuit and equalization method suitable for a series power battery pack. In the patent, the lithium-ion battery pack is divided into 2N three-cell battery modules, each of which is composed of three adjacent lithium-ion batteries, and has the following characteristics: each three-cell equalization submodule requires a bidirectional DC / DC converter, and only S2C and C2S equalization can be achieved between the three cells inside the submodule. Summary of the invention

[0008] The technical problem to be solved by the present invention is: how to find an ideal battery balancing technical solution, and therefore a multi-mode integrated power battery active equalizer design method is provided.

[0009] To achieve the above object, the present invention is achieved through the following technical solutions:

[0010] The multi-mode fusion power battery active equalizer is characterized in that: the active equalizer is arranged between the power battery modules, and is used to transfer the energy of the overcharged battery cell to the battery string, transfer the energy of the battery string to the undercharged battery cell, or directly transfer the energy of the overcharged battery cell to the undercharged battery cell, so as to achieve the SOC consistency of the battery cluster through active balancing;

[0011] The active equalizer is used to achieve the consistency of SOC of a battery string composed of n battery cells connected in series. The battery string is connected to a detection circuit, which is used to monitor the open circuit voltage and charge state of the battery. The detection circuit is connected to a microprocessor. The microprocessor is connected to a bidirectional converter through a drive circuit. The bidirectional converter is connected to the battery string through a bidirectional switch array.

[0012] When the battery charge states are inconsistent, different bidirectional switch arrays are formed to connect the target battery with the bidirectional converter to achieve battery cell to battery string balancing, battery string to battery cell balancing, or local battery cell to battery cell balancing;

[0013] The bidirectional converter is realized by a bidirectional Sepic converter including two N-channel enhancement mode MOS tubes, two magnetic inductors, one charge pump capacitor and two filter capacitors: a low voltage filter capacitor is arranged in parallel at the low voltage end, a high voltage filter capacitor is arranged in parallel at the high voltage end, the low voltage filter capacitor is connected with a first magnetic inductor and a first enhancement mode MOS tube, the high voltage filter capacitor is connected with a second magnetic inductor and a second enhancement mode MOS tube, and a charge pump capacitor is arranged between the first enhancement mode MOS tube and the second enhancement mode MOS tube;

[0014] In the bidirectional switch array, 2 (n+1) N-channel enhancement type MOS transistors are connected in series in pairs to form (n+1) bidirectional switches Sc1 -S c(n+1) The drain of the MOS tube at the lower end is connected to n battery cells B 1 -B n Directly connected, the drain of the odd-numbered MOS tube at the upper end is connected through the selection switch S K1 Connect to polarity switch S L2 , S L4 The left end and the polarity switch S H1 , S H3 The right end of the even-numbered MOS tube at the upper end is connected to the drain through the selection switch S K2 Connect to polarity switch S L1 , S L3 The left end and the polarity switch S H2 , S H4 The right end of the polarity switch S H6 Connect to battery cell B n The positive terminal and the polarity switch S H1 , S H3 The right end of the polarity switch S L1 , S L2 The right end of the bidirectional converter is connected to the low voltage side V L The positive polarity end is connected to the polarity switch S L3 , S L4 The right end of the bidirectional converter is connected to the low voltage side V L The negative polarity terminal is connected to the polarity switch S H1 , S H2 The left end of the bidirectional converter is connected to the high voltage side V H The positive polarity end is connected to the polarity switch S H3 , S H4 , S H5 The left end of the bidirectional converter is connected to the high voltage side V H The negative polarity terminal is connected to the polarity switch S H5 The right side is connected to the reference ground;

[0015] The detection circuit is used to monitor the battery voltage, and the sensor is used to collect battery signals. The sampled information generates a control signal through a microprocessor, which is isolated and amplified by a driving circuit to control the on and off of the switch devices in the bidirectional converter and the bidirectional switch array, so that energy flows from the high SOC battery to the low SOC battery, achieving consistency of the battery SOC.

[0016] When there are m battery cells in the battery string that are in an overcharged state, the active balancer will balance the overcharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. cm With S c(m+1) , Select switch S K1 With S K2 and polarity switch SH1 , S H5 With S H6 On this basis, when m is an odd number, the polarity switch S is controlled L1 , S L4 When m is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The boost mode on the side transfers the excess energy of the overcharged battery cell to the battery string, and the battery cell B is balanced through the C2S balance mode. m SOC consistency with the battery string.

[0017] When there are i battery cells in the battery string that are undercharged, the active balancer will balance the undercharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. ci With S c(i+1) , Select switch S K1 With S K2 and polarity switch S H1 , S H5 With S H6 On this basis, when i is an odd number, the polarity switch S is controlled L1 , S L4 When i is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V L The buck mode on the side transfers the battery string energy to the undercharged battery cell, and the battery cell B is realized through the S2C balancing mode. i SOC consistency with the battery string.

[0018] When there are j overcharged battery cells and q undercharged battery cells in the battery string at the same time, the active balancer will realize the balance from overcharged battery cells to undercharged battery cells according to the priority level. At this time, the switch S is selected. K1 With S K2 All disconnected;

[0019] When the number of overcharged battery cells is greater than n / 2 and the number of undercharged battery cells is less than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled H1 , S H4 When j is an even number, the polarity switch S is controlled.H2 , S H3 When q is an odd number, the polarity switch S is controlled. L1 , S L4 When q is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V L The voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency;

[0020] When the number of overcharged battery cells is less than n / 2 and the number of undercharged battery cells is greater than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled L1 , S L4 When j is an even number, the polarity switch S is controlled. L2 , S L3 When q is an odd number, the polarity switch S is controlled. H1 , S H4 When q is an even number, the polarity switch S is controlled. H2 , S H3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the present invention has outstanding substantial features and significant progress over the prior art. Specifically, the present invention provides a multi-mode fusion power battery active equalizer. By controlling and forming different bidirectional switch arrays to connect the target battery with the bidirectional converter, the equalizer can realize three modes of C2S (battery cell to battery string) balancing, S2C (battery string to battery cell) balancing and HAC2AC (local battery cell to battery cell) balancing, thereby effectively improving the balancing speed and efficiency of the power battery system under complex overcharging and undercharging conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a schematic diagram of the structure of the multi-mode fusion power battery active equalizer of the present invention;

[0023] Figure 2 A schematic diagram of a C2S balancing mode for realizing energy flow from an overcharged battery cell to a battery string when the battery cell number is an odd number;

[0024] Figure 3 A schematic diagram of a C2S balancing mode for realizing energy flow from an overcharged battery cell to a battery string when the battery cell number is an even number;

[0025] Figure 4 It is a schematic diagram of the S2C balancing mode for realizing the energy flow of the battery string to the undercharged battery cell when the battery cell number is an odd number;

[0026] Figure 5 It is a schematic diagram of the S2C balancing mode for realizing the energy flow of the battery string to the undercharged battery cell when the battery cell number is an even number;

[0027] Figure 6 To achieve V L Side voltage is higher than V H Side and V H Side voltage is higher than V L Schematic diagram of HAC2AC balancing mode where the energy from the overcharged battery cell on the side flows to the undercharged battery cell. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] like Figure 1As shown, the active balancer is arranged between the power battery modules to complete the C2S balance of transmitting the energy of the overcharged battery cells to the battery string, the S2C balance of transmitting the energy of the battery string to the undercharged battery cells, and the HAC2AC balance of directly transmitting the energy of the local overcharged battery cells to the undercharged battery cells, thereby achieving the SOC consistency of the battery cluster through the active balancing strategy of multi-mode fusion and improving the life and safety of the power battery.

[0031] The active equalizer is composed of a bidirectional switch array and a bidirectional converter, wherein the bidirectional converter is implemented by a bidirectional Sepic converter including two N-channel enhancement mode MOS tubes, two magnetic inductors, one charge pump capacitor and two filter capacitors. A low voltage capacitor C is connected in parallel at the low voltage end. L , a high voltage capacitor C is connected in parallel to the high voltage end H , the low voltage capacitor C L Connected with the first magnetic inductor L 1 And the first enhancement mode MOS tube Q 1 , the high voltage capacitor C H Connected with a second magnetic inductor L 2 And the second enhancement MOS tube Q 2 , in the first enhancement mode MOS tube Q 1 And the second enhancement MOS tube Q 2 A charge pump capacitor C is also provided between 1 .

[0032] In the bidirectional switch array, 2(n+1) N-channel enhancement MOS transistors are connected in series back-to-back to form (n+1) bidirectional switches S c1 -S c(n+1) The drain of the MOS tube at the lower end is connected to n battery cells B 1 -B n Directly connected, the drain of the odd-numbered MOS tube at the upper end is connected through the selection switch S K1 Connect to polarity switch S L2 , S L4 The left end and the polarity switch S H1 , S H3 The right end of the even-numbered MOS tube at the upper end is connected to the drain through the selection switch S K2 Connect to polarity switch S L1 , S L3 The left end and the polarity switch S H2 , S H4 The right end of the polarity switch S H6 Connect to battery cell B n The positive terminal and the polarity switch S H1 , S H3 The right end of the polarity switch S L1 , SL2 The right end of the bidirectional converter is connected to the low voltage side V L The positive polarity end is connected to the polarity switch S L3 , S L4 The right end of the bidirectional converter is connected to the low voltage side V L The negative polarity terminal is connected to the polarity switch S H1 , S H2 The left end of the bidirectional converter is connected to the high voltage side V H The positive polarity end is connected to the polarity switch S H3 , S H4 , S H5 The left end of the bidirectional converter is connected to the high voltage side V H The negative polarity terminal is connected to the polarity switch S H5 The right side is connected to the reference ground.

[0033] A multi-mode fusion power battery active balancer, for a battery string composed of n battery cells connected in series, when the SOC is inconsistent under complex overcharge and undercharge conditions, by controlling the conduction and shutdown of the switch devices in the active balancer, C2S balance, S2C balance and HAC2AC balance are achieved, achieving consistency and balanced operation of the power battery system:

[0034] (1) C2S Balance Mode

[0035] When there are m battery cells in the battery string that are in an overcharged state, the active balancer will balance the overcharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. cm With S c(m+1) , Select switch S K1 With S K2 and polarity switch S H1 , S H5 With S H6 On this basis, when m is an odd number, such as Figure 2 As shown, the control polarity switch S L1 , S L4 When m is an even number, Figure 3 As shown, the control polarity switch S L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The boost mode on the side transfers the excess energy of the overcharged battery cell to the battery string, and the battery cell B is balanced through the C2S balance mode. m SOC consistency with the battery string.

[0036] (2) S2C Balance Mode

[0037] When there are i battery cells in the battery string that are undercharged, the active balancer will balance the undercharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. ci With S c(i+1) , Select switch S K1 With S K2 and polarity switch S H1 , S H5 With S H6 On this basis, when i is an odd number, such as Figure 4 As shown, the control polarity switch S L1 , S L4 When i is an even number, Figure 5 As shown, the control polarity switch S L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V L The buck mode on the side transfers the battery string energy to the undercharged battery cell, and the battery cell B is realized through the S2C balancing mode. i SOC consistency with the battery string.

[0038] (3) HAC2AC balanced mode

[0039] When there are j overcharged battery cells and q undercharged battery cells in the battery string at the same time, the active balancer will implement HAC2AC balancing according to the priority level. Figure 6 As shown, select switch S K1 With S K2 All disconnected;

[0040] When the number of overcharged battery cells is greater than n / 2 and the number of undercharged battery cells is less than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled H1 , S H4 When j is an even number, the polarity switch S is controlled. H2 , S H3 When q is an odd number, the polarity switch S is controlled. L1 , S L4 When q is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V LThe voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency;

[0041] When the number of overcharged battery cells is less than n / 2 and the number of undercharged battery cells is greater than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled L1 , S L4 When j is an even number, the polarity switch S is controlled. L2 , S L3 When q is an odd number, the polarity switch S is controlled. H1 , S H4 When q is an even number, the polarity switch S is controlled. H2 , S H3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency;

[0042] The above process is repeated until the SOC difference between the battery string and the overcharged and undercharged battery cells is less than 1%, and the balancing is completed.

[0043] Compared with CN 103199589 A, this patent application has the following beneficial effects:

[0044] (1) The number of bidirectional converters required is different. CN 103199589 A requires four bidirectional converters (each bidirectional converter consists of one primary winding, three secondary windings, four RCD absorption circuits and seven NMOS switch tubes) to complete balancing, while the present invention only requires one bidirectional converter (consisting of two NMOS tubes, two magnetic inductors, one charge pump capacitor and two filter capacitors) to complete balancing. Therefore, under the premise that the sensing and monitoring circuits are the same, the present invention has lower cost and smaller volume;

[0045] (2) The balancing time is different from the balancing speed. The power battery is a complex and strongly nonlinear system. When there is one overcharged battery cell and one undercharged battery cell in the three battery cells in the module, CN 103199589 A needs to first transfer the energy of the overcharged battery cell to the battery submodule via a bidirectional converter, and then the battery submodule transfers the energy to the undercharged battery cell, so as to achieve submodule balancing. However, the present invention can use the HAC2AC mode to directly transfer the energy of the overcharged battery cell to the undercharged battery cell. Therefore, under complex working conditions, the balancing time required by the present invention is half of that of CN 103199589 A, and the balancing speed is faster.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. Multi-mode fusion power battery active equalizer, characterized by: The active equalizer is set between the power battery modules to transfer the energy of the overcharged battery cells to the battery string, transfer the energy of the battery string to the undercharged battery cells, or directly transfer the energy of the overcharged battery cells to the undercharged battery cells, so as to achieve the SOC consistency of the battery cluster through active balancing; The active equalizer is used to achieve the consistency of SOC of a battery string composed of n battery cells connected in series. The battery string is connected to a detection circuit, which is used to monitor the open circuit voltage and charge state of the battery. The detection circuit is connected to a microprocessor. The microprocessor is connected to a bidirectional converter through a drive circuit. The bidirectional converter is connected to the battery string through a bidirectional switch array. When the battery charge states are inconsistent, different bidirectional switch arrays are formed to connect the target battery with the bidirectional converter to achieve battery cell to battery string balancing, battery string to battery cell balancing, or local battery cell to battery cell balancing; The bidirectional converter is realized by a bidirectional Sepic converter including two N-channel enhancement mode MOS tubes, two magnetic inductors, one charge pump capacitor and two filter capacitors: a low voltage filter capacitor is arranged in parallel at the low voltage end, a high voltage filter capacitor is arranged in parallel at the high voltage end, the low voltage filter capacitor is connected with a first magnetic inductor and a first enhancement mode MOS tube, the high voltage filter capacitor is connected with a second magnetic inductor and a second enhancement mode MOS tube, and a charge pump capacitor is arranged between the first enhancement mode MOS tube and the second enhancement mode MOS tube; In the bidirectional switch array, 2 (n+1) N-channel enhancement type MOS transistors are connected in series in pairs to form (n+1) bidirectional switches S c1 -S c(n+1) The drain of the MOS tube at the lower end is connected to n battery cells B1-B n Directly connected, the drain of the odd-numbered MOS tube at the upper end is connected through the selection switch S K1 Connect to polarity switch S L2 , S L4 The left end and the polarity switch S H1 , S H3 The right end of the even-numbered MOS tube at the upper end is connected to the drain through the selection switch S K2 Connect to polarity switch S L1 , S L3 The left end and the polarity switch S H2 , S H4 The right end of the polarity switch S H6 Connect to battery cell B n The positive terminal and the polarity switch S H1 , S H3 The right end of the polarity switch S L1 , S L2 The right end of the bidirectional converter is connected to the low voltage side V L The positive polarity end is connected to the polarity switch S L3 , S L4 The right end of the bidirectional converter is connected to the low voltage side V L The negative polarity terminal is connected to the polarity switch S H1 , S H2 The left end of the bidirectional converter is connected to the high voltage side V H The positive polarity end is connected to the polarity switch S H3 , S H4 , S H5 The left end of the bidirectional converter is connected to the high voltage side V H The negative polarity terminal is connected to the polarity switch S H5 The right side is connected to the reference ground; The detection circuit is used to monitor the battery voltage, and the sensor is used to collect battery signals. The sampled information generates a control signal through a microprocessor, which is isolated and amplified by a driving circuit to control the on and off of the switch devices in the bidirectional converter and the bidirectional switch array, so that energy flows from the high SOC battery to the low SOC battery, achieving consistency of the battery SOC.

2. The multi-mode fusion power battery active equalizer according to claim 1 is characterized in that: When there are m battery cells in the battery string that are in an overcharged state, the active balancer will balance the overcharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. cm With S c(m+1) , Select switch S K1 With S K2 and polarity switch S H1 , S H5 With S H6 On this basis, when m is an odd number, the polarity switch S is controlled L1 , S L4 When m is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The boost mode on the side transfers the excess energy of the overcharged battery cell to the battery string, and the battery cell B is balanced through the C2S balance mode. m SOC consistency with the battery string.

3. The multi-mode fusion power battery active equalizer according to claim 1 is characterized in that: When there are i battery cells in the battery string that are undercharged, the active balancer will balance the undercharged battery cells in turn according to the priority level; at this time, the bidirectional switch S is controlled and driven. ci With S c(i+1) , Select switch S K1 With S K2 and polarity switch S H1 , S H5 With S H6 On this basis, when i is an odd number, the polarity switch S is controlled L1 , S L4 When i is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V L The buck mode on the side transfers the battery string energy to the undercharged battery cell, and the battery cell B is realized through the S2C balancing mode. i SOC consistency with the battery string.

4. The multi-mode fusion power battery active equalizer according to claim 1 is characterized in that: When there are j overcharged battery cells and q undercharged battery cells in the battery string at the same time, the active balancer will realize the balance from overcharged battery cells to undercharged battery cells according to the priority level. At this time, the switch S is selected. K1 With S K2 All disconnected; When the number of overcharged battery cells is greater than n / 2 and the number of undercharged battery cells is less than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled H1 , S H4 When j is an even number, the polarity switch S is controlled. H2 , S H3 When q is an odd number, the polarity switch S is controlled. L1 , S L4 When q is an even number, the polarity switch S is controlled. L2 , S L3 Turn on; design the bidirectional converter to work when the energy is from V H Side flow V L The voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency; When the number of overcharged battery cells is less than n / 2 and the number of undercharged battery cells is greater than n / 2, the bidirectional switch S is controlled and driven. cj With S c(j+1) , Bidirectional switch S cq With S c(q+1) On this basis, when j is an odd number, the polarity switch S is controlled L1 , S L4 When j is an even number, the polarity switch S is controlled. L2 , S L3 When q is an odd number, the polarity switch S is controlled. H1 , S H4 When q is an even number, the polarity switch S is controlled. H2 , S H3 Turn on; design the bidirectional converter to work when the energy is from V L Side flow V H The voltage reduction mode on the side is used to transfer the energy of the overcharged battery cell to the undercharged battery cell, and the battery cell B is balanced by the HAC2AC mode. q With B j SOC consistency.

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