Active equalization circuit system of energy storage unit

Abstract

The utility model discloses an active equalization circuit system of an energy storage unit. The active equalization circuit system comprises energy storage units of a plurality of battery packs, a BMS module and a plurality of equalization circuits corresponding to the plurality of battery packs. The BMS module respectively monitors the electric quantity states of a plurality of battery packs in the energy storage unit, the plurality of battery packs in the energy storage unit are sequentially connected in series, and the plurality of battery packs in the energy storage unit are electrically connected to one side of the corresponding equalization circuit; the other side of any one of the plurality of equalization circuits is electrically connected with the other equalization circuits of the plurality of equalization circuits through transistor switches; the BMS module controls the on and off of a plurality of transistor switches, and controls the on and off of a transistor in any equalization circuit, so that the corresponding equalization circuit performs discharging and charging operations; the electric quantity difference of other battery packs is small, the battery pack with the high electric quantity can charge the battery pack with the low electric quantity more easily, the stability and safety of the battery packs and the equalization circuit are guaranteed, and the equalization operation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of battery circuit technology, and particularly to an active balancing circuit system for an energy storage unit. Background Technology

[0002] When a transformer is used as the main component of the equalization circuit, during the operation of the equalization circuit, if some battery packs have higher charge levels while others have lower charge levels and the difference in charge levels between the other battery packs is not significant, it will be difficult for the higher-charge battery packs to transfer charge to the other lower-charge battery packs during the equalization operation via the BMS module. This will greatly affect the efficiency of the equalization circuit's charge equalization operation. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides an active balancing circuit system for an energy storage unit, which is equipped with several balancing circuits to perform balancing operations on several battery packs, and a transistor switch is set up to solve the problem of difficulty in power transfer when some battery packs have higher power and the power difference of other battery packs is not significant.

[0004] Technical Solution: To achieve the above objectives, this utility model provides an active balancing circuit system for an energy storage unit, comprising an energy storage unit with several battery packs, a BMS module, and several balancing circuits corresponding to the battery packs. The BMS module monitors the charge status of the several battery packs in the energy storage unit. The several battery packs in the energy storage unit are connected in series. Each battery pack in the energy storage unit is electrically connected to one side of the balancing circuit corresponding to it. The other side of any one of the balancing circuits is electrically connected to the other balancing circuits in the balancing circuit via a transistor switch. The BMS module controls the on and off of the transistor switches and controls the on and off of the transistors in any one of the balancing circuits, enabling the corresponding balancing circuit to perform discharge and charge operations.

[0005] Furthermore, the circuit structures of the various equalization circuits are all the same, and each of the various equalization circuits includes an inductor, a capacitor, a transformer, two transistors and two resistors.

[0006] Furthermore, the first equalization circuit in the plurality of equalization circuits includes an L1 inductor, a C1 capacitor, a TN transformer, an MN1 transistor, an MN2 transistor, an R1 resistor, and an R2 resistor; one end of one coil of the TN transformer is electrically connected to the drain of the MN2 transistor, and the source of the MN2 transistor is electrically connected to one end of the R2 resistor, forming a discharge circuit.

[0007] Furthermore, one end of the coil on one side of the TN transformer is electrically connected to the positive terminal of the battery pack, and the other end of the resistor R2 is electrically connected to the negative terminal of the battery pack.

[0008] Furthermore, one end of the coil on the other side of the TN transformer is electrically connected to the drain of the MN1 transistor, and the source of the MN1 transistor is electrically connected to one end of the R1 resistor, forming a charging circuit.

[0009] Furthermore, the other end of the coil on the other side of the TN transformer is electrically connected to one end of the M1 transistor switch corresponding to the first equalization circuit through the L1 inductor, and the other end of the M1 transistor switch is electrically connected to the remaining equalization circuits through the transistor switches corresponding to the remaining equalization circuits; the other end of the R1 resistor is grounded.

[0010] Furthermore, the charging circuit is connected in parallel with capacitor C1, one end of which is electrically connected to the other end of the coil on the other side of the TN transformer, and the other end of which is electrically connected to the other end of resistor R1.

[0011] Furthermore, when the BMS module detects that some battery packs have high charge levels and the charge difference of other battery packs is less than the threshold H, the BMS module controls the transistor switch corresponding to the high-charge battery packs to turn off for a period of time T before turning it on again.

[0012] Beneficial effects: The active balancing circuit system of the energy storage unit of this utility model constructs a balanced power through a transformer and combines two transistors to realize bidirectional balancing operation of battery pack discharge and charging; and is equipped with capacitors and transistor switches to make it easier for the battery pack with higher power to charge the battery pack with lower power when the power of other battery packs is not much different, so as to ensure the stability and safety of battery pack and balancing circuit, while improving the efficiency of balancing operation. Attached Figure Description

[0013] Figure 1 This is a circuit diagram of an active equalization circuit. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] like Figure 1As shown, an active balancing circuit system for an energy storage unit includes an energy storage unit with several battery packs, a BMS module 2, and several balancing circuits corresponding to the battery packs. The BMS module 2 monitors the charge status of the several battery packs in the energy storage unit. The several battery packs in the energy storage unit are connected in series. Each of the several battery packs in the energy storage unit is electrically connected to one side of the balancing circuit corresponding to its respective balancing circuit. The other side of any balancing circuit is electrically connected to the other balancing circuits in the several balancing circuits through a transistor switch. The BMS module 2 controls the on and off of the several transistor switches, and controls the on and off of the transistors in any of the several balancing circuits, so that the corresponding balancing circuit can perform discharge and charge operations.

[0016] The BMS module 2 includes several BMS sub-modules and a main control module. Each BMS sub-module corresponds to one of the battery packs. The BMS sub-modules collect the status data or power data of their corresponding battery packs, obtain the power data of the battery packs, and transmit it to the main control module. The main control module performs active balancing operations based on the power of each battery in the battery packs, controlling the conduction and cutoff of transistors in the balancing circuit, as well as the conduction and cutoff of transistor switches corresponding to the balancing circuits, to realize the transfer of power from high-power battery packs to low-power battery packs, thereby achieving power balancing of all battery packs in the energy storage module.

[0017] The circuit structures of several equalization circuits are all the same, and each of the several equalization circuits includes an inductor, a capacitor, a transformer, two transistors and two resistors.

[0018] The first equalization circuit in the plurality of equalization circuits includes an L1 inductor, a C1 capacitor, a TN transformer 11, an MN1 transistor, an MN2 transistor, a R1 resistor, and an R2 resistor; one end of one coil of the TN transformer 11 is electrically connected to the drain of the MN2 transistor, and the source of the MN2 transistor is electrically connected to one end of the R2 resistor, forming a discharge circuit.

[0019] One end of the coil of the TN transformer 11 is electrically connected to the positive terminal of the battery pack, and the other end of the resistor R2 is electrically connected to the negative terminal of the battery pack.

[0020] One end of the coil on the other side of the TN transformer 11 is electrically connected to the drain of the MN1 transistor, and the source of the MN1 transistor is electrically connected to one end of the R1 resistor, forming a charging circuit.

[0021] The aforementioned equalization circuits control charging and discharging operations by turning on and off two internal transistors. High-capacity batteries discharge, while low-capacity battery packs charge. Taking the first equalization circuit as an example, when transistor MN1 is turned off and transistor MN2 is turned on, the equalization circuit is in a discharging state, and the corresponding battery pack discharges through a transformer. When transistor MN1 is turned on and transistor MN2 is turned off, the equalization circuit is in a charging state, and the corresponding battery pack charges through a transformer.

[0022] The other end of the coil on the other side of the TN transformer 11 is electrically connected to one end of the M1 transistor switch corresponding to the first equalization circuit through the L1 inductor. The other end of the M1 transistor switch is electrically connected to the other equalization circuits through the transistor switches corresponding to the other equalization circuits. The other end of the R1 resistor is grounded.

[0023] The charging circuit has a capacitor C1 connected in parallel. One end of capacitor C1 is electrically connected to the other end of the coil on the other side of the TN transformer 11, and the other end of capacitor C1 is electrically connected to the other end of resistor R1. The inductors in the balancing circuit and the capacitor connected in parallel with the charging circuit play a role in protecting the balancing circuit and the battery pack during normal balancing operation.

[0024] When BMS module 2 detects that some battery packs have high charge and the charge difference of other battery packs is less than the threshold H, BMS module 2 controls the transistor switch corresponding to the high-charge battery packs to turn off for a period of time T and then turn on. At this time, the discharge circuit in the equalization circuit corresponding to the high-charge battery packs will work and continue to discharge.

[0025] After a period of time T is disconnected, the transistor switches corresponding to a portion of the high-charge battery packs are turned on via the BMS module 2, while the transistor switches corresponding to the other low-charge battery packs are turned on. The charging circuit in the equalization circuit corresponding to the low-charge battery packs is activated to perform the charging operation, thereby achieving the equalization of battery charge.

[0026] The threshold H is set according to requirements. When the difference is less than the threshold, the difference in charge level between the lower-charge battery packs is not significant, making it difficult for the higher-charge battery pack to transfer charge to the lower-charge battery pack. When the difference is not less than the threshold, the higher-charge battery pack can easily transfer heat to the lower-charge battery pack, thus eliminating the need for such an operation. The time T is determined based on the time it takes for the capacitor to fully charge. The equalization circuit of the fully charged capacitor and the discharging battery packs charges the lower-charge battery packs.

[0027] When using a transformer for balancing circuit operation, suppose some battery packs have higher charge levels, while other battery packs have lower charge levels compared to the higher charge packs, and the difference in charge levels among the other battery packs is not significant. Therefore, when performing balancing operations through the BMS module, it is difficult for the higher charge battery packs to transfer charge to the other lower charge battery packs, which greatly affects the charge balancing operation of the balancing circuit.

[0028] At this point, the transistor switches corresponding to a few battery packs with relatively high charge are turned off. These packs remain in a discharging state, and the transformer converts the charge and stores it in the capacitor connected in parallel with the charging circuit. After a period of time T, the transistor switches of these few battery packs are turned on again. The charge converted by the transformer and the charge in the capacitor simultaneously transfer charge outwards. Meanwhile, the other low-charge battery packs are charging. The current released from the capacitor and the current converted by the transformer from the battery packs combine to form a large current. This large current makes it easier for the low-charge battery packs to transfer charge. Therefore, it is easier for the charge of the few high-charge battery packs and the charge in their corresponding capacitors to charge the low-charge battery packs, improving the balancing efficiency of the balancing circuit.

[0029] Meanwhile, when the BMS module monitors the power status data of several battery packs, it can turn off the transistor switches corresponding to several battery packs. At this time, the BMS module controls the battery packs with higher power to discharge and the battery packs with lower power to charge. After a period of time T, it turns on all the transistor switches corresponding to several battery packs to perform power balancing. This operation speeds up the power balancing effect.

[0030] The above description is merely a preferred embodiment of the present utility model. Those skilled in the art can make several modifications and optimizations based on the above disclosure without departing from the basic principles described above. These modifications and optimizations should be considered as the scope of protection of the present utility model as understood.

Claims

1. An active balancing circuit system for an energy storage unit, characterized in that: The system includes an energy storage unit with several battery packs, a BMS module (2), and several equalization circuits corresponding to the battery packs. The BMS module (2) monitors the charge status of several battery packs in the energy storage unit. The battery packs in the energy storage unit are connected in series. Each battery pack in the energy storage unit is electrically connected to one side of the equalization circuit corresponding to it. The other side of any equalization circuit is electrically connected to the other equalization circuits in the equalization circuits through a transistor switch. The BMS module (2) controls the on and off of several transistor switches. The BMS module (2) controls the on and off of the transistors in any equalization circuit in the equalization circuits, so that the corresponding equalization circuit can perform discharge and charge operations.

2. The active balancing circuit system for an energy storage unit according to claim 1, characterized in that: The circuit structures of several equalization circuits are all the same, and each of the several equalization circuits includes an inductor, a capacitor, a transformer, two transistors and two resistors.

3. The active balancing circuit system for an energy storage unit according to claim 1, characterized in that: The first equalization circuit in the plurality of equalization circuits includes an L1 inductor, a C1 capacitor, a TN transformer (11), an MN1 transistor, an MN2 transistor, a R1 resistor, and an R2 resistor; one end of one coil of the TN transformer (11) is electrically connected to the drain of the MN2 transistor, and the source of the MN2 transistor is electrically connected to one end of the R2 resistor, forming a discharge circuit.

4. The active balancing circuit system for an energy storage unit according to claim 3, characterized in that: One end of the coil of the TN transformer (11) is electrically connected to the positive terminal of the battery pack, and the other end of the resistor R2 is electrically connected to the negative terminal of the battery pack.

5. The active balancing circuit system for an energy storage unit according to claim 3, characterized in that: One end of the coil on the other side of the TN transformer (11) is electrically connected to the drain of the MN1 transistor, and the source of the MN1 transistor is electrically connected to one end of the R1 resistor, forming a charging circuit.

6. The active balancing circuit system for an energy storage unit according to claim 5, characterized in that: The other end of the coil on the other side of the TN transformer (11) is electrically connected to one end of the M1 transistor switch corresponding to the first equalization circuit through the L1 inductor. The other end of the M1 transistor switch is electrically connected to the other equalization circuits through the transistor switches corresponding to the other equalization circuits. The other end of the R1 resistor is grounded.

7. The active balancing circuit system for an energy storage unit according to claim 5, characterized in that: The charging circuit is connected in parallel with capacitor C1. One end of capacitor C1 is electrically connected to the other end of the coil on the other side of the TN transformer (11), and the other end of capacitor C1 is electrically connected to the other end of resistor R1.

8. The active balancing circuit system for an energy storage unit according to claim 5, characterized in that: When the BMS module (2) detects that some of the battery packs have high charge and the charge difference of the other battery packs is less than the threshold H, the BMS module (2) controls the transistor switch corresponding to the high charge battery pack to turn off for a period of time T and then turn on.

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