Balanced topology circuit of new energy storage battery and control method thereof

Abstract

The invention discloses an equalization topology circuit of a new energy storage battery and a control method of the equalization topology circuit, and relates to the technical field of power electronics and energy storage. Comprising the steps that when the charge state of a first battery module is higher than the average value of the charge states of three battery modules, an input control signal of a first power MOSFET switch is set to be high level, the first power MOSFET switch is turned on, the first battery module discharges, and a first energy storage inductor stores energy; when the state of charge is equal to the average state of charge, the input control signal of the first power MOSFET switch is set to be at a low level, the first power MOSFET switch is turned off, the electric energy of the first battery module is converted into magnetic energy, the magnetic energy is stored in the first energy storage inductor, the current is gradually reduced to zero, and the magnetic energy in the first energy storage inductor is released and converted into the electric energy again. According to the invention, the problem of inconsistency of the lithium battery pack in the new energy storage system can be solved.

Description

Technical Field

[0001] The present invention relates to the technical fields of power electronics and energy storage, and particularly relates to a balancing topology circuit for a new energy storage battery and a control method therefor. Background Art

[0002] With the rapid expansion of the electric vehicle market, in the future, the treatment of retired lithium-ion batteries will become a new problem. Compared with traditional material recycling solutions, the recycling of retired batteries is more economical and environmentally friendly. In fact, retired batteries can still maintain nearly 70% - 80% of their initial capacity, which is sufficient for safe use in certain scenarios, such as electric bicycles, low-speed electric vehicles, and energy storage systems. However, due to the different aging degrees of each recycled battery, there may be a serious risk of energy mismatch in the reconfigured battery pack. Therefore, an active battery balancing method is needed to maximize the utilization of recycled batteries.

[0003] Active balancing methods can transfer energy from high-voltage batteries to low-voltage batteries to mitigate the energy mismatch condition. According to the energy balancing method, they can be divided into five categories: transfer between adjacent batteries (AC2C), direct transfer between batteries (DC2C), from cell to stack (C2S), from stack to cell (S2C), and transfer between any battery cells (AC2AC).

[0004] The AC2C balancing method transfers energy between adjacent monomers. Its characteristics are simple structure and strong scalability. However, when the target battery monomers are far apart from each other, multiple conversions are required. This reduces the overall efficiency, especially in the case of a long battery pack. The DC2C balancing method uses a selection switch to directly transfer energy from the battery with the highest voltage to the battery with the lowest voltage, which improves the balancing efficiency to a certain extent. However, numerous selection switches make the system large and complex. The C2S and S2C balancing methods transfer energy between unbalanced cells and the battery stack. Since the battery stack works as a whole, some balanced cells may undergo unnecessary charge and discharge.

[0005] In addition, when balancing the target battery monomer by the above energy balancing methods, other battery monomers must wait for the target battery monomer to complete the balancing. However, in the lithium battery pack existing in the new energy storage system, when there are a large number of unbalanced batteries in the battery pack, the balancing takes a long time and the balancing rate is low. Summary of the Invention

[0006] Based on this, it is necessary to provide a balancing topology circuit for a new energy storage battery and a control method therefor in view of the above technical problems.

[0007] An embodiment of the present invention provides a balancing topology circuit for a new energy storage battery, including: a multi-stage single-layer buck-boost balancing topology, and adjacent single-layer buck-boost balancing topologies are connected through an additional energy storage inductor, an additional power MOSFET switch and its additional body diode; The single-layer buck-boost balancing topology includes: a first energy storage inductor, a second energy storage inductor, a first power MOSFET switch and its first body diode, a second power MOSFET switch and its second body diode, a third power MOSFET switch and its third body diode, a fourth power MOSFET switch and its fourth body diode, a first battery module, a second battery module, and a third battery module; The drain of the first power MOSFET switch is connected to the positive electrode of the first battery module and the drain of the third power MOSFET switch, and the gate of the first power MOSFET switch is connected to the drain of the second power MOSFET switch and one end of the first energy storage inductor; the other end of the first energy storage inductor is connected to the negative electrode of the first battery module and the positive electrode of the second battery module; The drain of the second power MOSFET switch is connected to the negative electrode of the third battery module and the source of the fourth power MOSFET switch, the positive electrode of the third battery module is connected to the negative electrode of the second battery module and one end of the second energy storage inductor; the other end of the second energy storage inductor is connected to the source of the third power MOSFET switch and the drain of the fourth power MOSFET switch.

[0008] Optionally, the drain of the additional power MOSFET switch is connected to the drain of the third power MOSFET switch, the source of the additional power MOSFET switch is connected to the drain of the adjacent additional power MOSFET switch and one end of the additional energy storage inductor, and the other end of the additional energy storage inductor is connected to the adjacent single-layer buck-boost balancing topology.

[0009] Optionally, the positive electrode of the additional body diode is connected to the source of the additional power MOSFET switch, and the negative electrode of the additional body diode is connected to the drain of the additional power MOSFET switch.

[0010] Optionally, the positive electrode of the first body diode is connected to the source of the first power MOSFET switch, and the negative electrode of the first body diode is connected to the drain of the first power MOSFET switch; The positive electrode of the second body diode is connected to the source of the second power MOSFET switch, and the negative electrode of the second body diode is connected to the drain of the second power MOSFET switch; The positive electrode of the third body diode is connected to the source of the third power MOSFET switch, and the negative electrode of the third body diode is connected to the drain of the third power MOSFET switch; The positive electrode of the fourth body diode is connected to the source electrode of the fourth power MOSFET switch, and the negative electrode of the fourth body diode is connected to the drain electrode of the fourth power MOSFET switch.

[0011] An embodiment of the present invention further provides a control method for an equalization topology circuit of a new energy storage battery, including: Obtain the state of charge of the first battery module, the state of charge of the second battery module, and the state of charge of the third battery module, and calculate the average value of the state of charge of the first battery module, the second battery module, and the third battery module; Compare the state of charge of each battery module with the average value respectively, and control the on-off states of each component in the equalization topology circuit according to the comparison results.

[0012] Optionally, controlling the on-off states of each component in the equalization topology circuit according to the comparison results includes: When the state of charge of the first battery module is higher than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the first power MOSFET switch to a high level, the first power MOSFET switch conducts, the first battery module discharges, and the first energy storage inductor stores energy; when the state of charge of the first battery module is less than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the first power MOSFET switch to a low level, the second power MOSFET switch conducts, the second battery module and the third battery module discharge, and the first energy storage inductor stores energy; When the state of charge is equal to the average state of charge, set the input control signal of the first power MOSFET switch to a low level and turn off the first power MOSFET switch; after the first power MOSFET switch is turned off, the first energy storage inductor, the second battery module, the third battery module, and the second body diode form a loop, the current gradually decreases to zero, and the energy stored in the first energy storage inductor is released and reconverted into electrical energy; set the input control signal of the second power MOSFET switch to a low level and turn off the second power MOSFET switch; When the state of charge of the first battery module and the second battery module is higher than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the third power MOSFET switch to a high level, the third power MOSFET switch conducts, the first battery module and the second battery module discharge, and the second energy storage inductor stores energy; when the state of charge of the first battery module and the second battery module is less than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the third power MOSFET switch to a low level, and then the fourth power MOSFET switch conducts, the third battery module discharges, and the second energy storage inductor stores energy; When the state of charge of the first battery module and the second battery module is equal to the average value of the state of charge of the first battery module, the second battery module, and the third battery module, turn off the third power MOSFET switch and the fourth power MOSFET switch.

[0013] The above-mentioned balanced topology circuit and its control method for a new energy storage battery provided by the embodiments of the present invention have the following beneficial effects compared with the prior art: The present invention transforms the buck-boost converter widely used in power electronics technology into a buck-boost balanced topology, compares the state of charge of each battery module with the state of charge of each battery module, and controls the opening and closing states of each component in the balanced topology circuit according to the comparison result, which can reduce the possibility of problems such as performance degradation and damage of lithium batteries caused by the long-term inconsistency of lithium battery packs in the energy storage system; through balanced control, the influence caused by natural inconsistencies caused by production conditions and working environments is minimized as much as possible, and the structure and balanced strategy are optimized, thereby reducing time costs and economic costs.

[0014] In addition, the present invention proposes a control method for the balanced topology circuit of a new energy storage battery, which has a faster balancing rate than the traditional double-layer buck-boost balanced topology under the condition of using fewer components, that is, lower cost. Description of the Drawings

[0015] Figure 1 It is a flow chart of the balancing method of the balanced topology circuit of a new energy storage battery provided in an embodiment; Figure 2 It is a schematic diagram of the traditional buck-boost balanced topology of the balanced topology circuit of a new energy storage battery provided in an embodiment; Figure 3 It is a schematic diagram of the improved double-layer buck-boost balanced topology of the balanced topology circuit of a new energy storage battery provided in an embodiment; Figure 4 It is a schematic diagram of the improved buck-boost balanced topology of the balanced topology circuit of a new energy storage battery provided in an embodiment; Figure 5 It is a schematic diagram of the traditional double-layer buck-boost balanced topology of the balanced topology circuit of a new energy storage battery provided in an embodiment; Figure 6 It is a working principle diagram of the second layer of the improved balanced topology of the balanced topology circuit of a new energy storage battery provided in an embodiment, Figure 6 in which (a) is the process of the first battery module transferring energy to the second battery module,Figure 6 In (b), it is the process of the second battery module transferring energy to the first battery module; Figure 7 It is the working schematic diagram of the improved first layer of the balancing topology of a balancing topology circuit for a new energy storage battery provided in an embodiment; Figure 7 In (a), it is the process of the first battery module transferring energy to the second battery module and the third battery module, Figure 7 In (b), it is the process of the second battery module and the third battery module transferring energy to the first battery module, Figure 7 In (c), it is the process of the battery cells of the first battery module and the second battery module transferring energy to the third battery module, Figure 7 In (d), it is the process of the battery cells of the third battery module transferring energy to the first battery module and the second battery module; Figure 8 It is the flowchart of the double-layer balancing control method of a control method for a balancing topology circuit of a new energy storage battery provided in an embodiment; Figure 9 It is the balancing simulation model diagram of a control method for a balancing topology circuit of a new energy storage battery provided in an embodiment; Figure 10 It is the simulation result diagram of the balancing process of the improved balancing circuit of a control method for a balancing topology circuit of a new energy storage battery provided in an embodiment; Figure 11 It is the simulation result diagram of the traditional balancing circuit of a control method for a balancing topology circuit of a new energy storage battery provided in an embodiment; Figure 12 It is the comparison diagram of two balancing methods under the UDDS condition of a control method for a balancing topology circuit of a new energy storage battery provided in an embodiment. Specific embodiments

[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] In one embodiment, a balancing topology circuit for a new energy storage battery and its control method are provided. As Figure 1 shown, the process includes: S101: Analyze the traditional buck-boost balancing topology and the proposed optimized buck-boost balancing topology; S102: Design the balancing strategy for the provided balancing topology; S103: Perform specific calculations on the balanced topology parameters; S104: Simulate the provided balanced topology.

[0018] In one embodiment, a balanced topology circuit for a new energy storage battery is provided, including: a multi-level single-layer buck-boost balanced topology. The single-layer buck-boost balanced topology includes: a first energy storage inductor L1, a second energy storage inductor L2, a first power MOSFET switch Q1 and its first body diode D1, a second power MOSFET switch Q2 and its second body diode D2, a third power MOSFET switch Q3 and its third body diode D3, a fourth power MOSFET switch Q4 and its fourth body diode D4, a first battery module, a second battery module, and a third battery module. Among them, the first battery module, the second battery module, and the third battery module are denoted as B 3N-2 , B 3N-1 and B 3N , where N is the number of levels of the single-layer buck-boost balanced topology; for example, the first battery module, the second battery module, and the third battery module of the first-level single-layer buck-boost balanced topology are denoted as B1, B2, and B3, and the first battery module, the second battery module, and the third battery module of the second-level single-layer buck-boost balanced topology are denoted as B4, B5, and B6.

[0019] The drain of the first power MOSFET switch Q1 is connected to the positive electrode of the first battery module and the drain of the third power MOSFET switch Q3. The gate of the first power MOSFET switch Q1 is connected to the drain of the second power MOSFET switch Q2 and one end of the first energy storage inductor L1. The other end of the first energy storage inductor L1 is connected to the negative electrode of the first battery module and the positive electrode of the second battery module.

[0020] The drain of the second power MOSFET switch Q2 is connected to the negative electrode of the third battery module and the source of the fourth power MOSFET switch Q4. The positive electrode of the third battery module is connected to the negative electrode of the second battery module and one end of the second energy storage inductor L2. The other end of the second energy storage inductor L2 is connected to the source of the third power MOSFET switch Q3 and the drain of the fourth power MOSFET switch Q4.

[0021] Adjacent single - layer buck - boost equalization topologies are connected by an additional energy - storage inductor Ls, an additional power MOSFET switch Qs and its additional body diode Ds. Among them, the drain of the additional power MOSFET switch Qs is connected to the drain of the third power MOSFET switch Q3. The source of the additional power MOSFET switch Qs is connected to the drain of the adjacent additional power MOSFET switch Qs and one end of the additional energy - storage inductor Ls. The other end of the additional energy - storage inductor Ls is connected to the adjacent single - layer buck - boost equalization topology. The anode of the additional body diode Ds is connected to the source of the additional power MOSFET switch Qs, and the cathode of the additional body diode Ds is connected to the drain of the additional power MOSFET switch Qs.

[0022] The anode of the first body diode D1 is connected to the source of the first power MOSFET switch Q1, and the cathode of the first body diode D1 is connected to the drain of the first power MOSFET switch Q1. The anode of the second body diode D2 is connected to the source of the second power MOSFET switch Q2, and the cathode of the second body diode D2 is connected to the drain of the second power MOSFET switch Q2. The anode of the third body diode D3 is connected to the source of the third power MOSFET switch Q3, and the cathode of the second body diode D2 is connected to the drain of the third power MOSFET switch Q3. The anode of the fourth body diode D4 is connected to the source of the fourth power MOSFET switch Q4, and the cathode of the fourth body diode D4 is connected to the drain of the fourth power MOSFET switch Q4.

[0023] As Figure 2 shown, the traditional buck - boost equalization topology of the new - energy energy - storage battery based on the power electronic converter provided by the embodiment of the present invention consists of two energy - storage inductors (L1 and L2), four power MOSFET switches (Q1, Q2, Q3 and Q4) and body diodes (D1, D2, D3 and D4).

[0024] As Figure 4 shown, taking three battery cells in series as an example, the two - stage topology structure consists of 2 inductors, 4 MOSFET switches and 4 diodes. Just for three batteries, the number of components used is the same as that of the traditional buck - boost, but it has more advantages through structural improvement and control strategy design.

[0025] As Figure 3 and 5 shown, Figure 3 the two - stage topology structure shown consists of n - 1 inductors, 2n - 2 MOSFET switches and 2n - 2 diodes. Figure 5The shown secondary topology consists of n + 2 inductors, 2n + n / 3 MOSFET switches, and 2n + n / 3 diodes. Compared with the two, the improved equalization topology can save 3 inductors, 2 + n / 3 MOSFETs and diodes.

[0026] In one embodiment, a control method for an equalization topology circuit of a new energy storage battery is provided, including: Obtain the state of charge of the first battery module, the state of charge of the second battery module, and the state of charge of the third battery module, and calculate the average value of the state of charge of the first battery module, the second battery module, and the third battery module.

[0027] Compare the state of charge of each battery module with the average value respectively, and control the opening and closing states of each component in the equalization topology circuit according to the comparison results.

[0028] As Figure 6 shown, taking the operation of the first power MOSFET switch Q1 of the first-stage single-layer buck-boost equalization topology as an example, When the state of charge of the first battery module is higher than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the first power MOSFET switch Q1 to high level, the first power MOSFET switch Q1 conducts, the first battery module discharges, and the first energy storage inductor L1 stores energy. When the state of charge of the first battery module is less than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, set the input control signal of the first power MOSFET switch Q1 to low level, the second power MOSFET switch Q2 conducts, the second battery module and the third battery module discharge, and the first energy storage inductor L1 stores energy.

[0029] When the state of charge is equal to the average state of charge, set the input control signal of the first power MOSFET switch Q1 to low level and turn off the first power MOSFET switch Q1. After the first power MOSFET switch Q1 is turned off, a loop is formed by the first energy storage inductor L1, the second battery module, the third battery module, and the second body diode D2, and the current gradually decreases to zero. The energy stored in the first energy storage inductor L1 is released and re-converted into electrical energy. Set the input control signal of the second power MOSFET switch Q2 to low level and turn off the second power MOSFET switch Q2.

[0030] When the state of charge of the first battery module and the second battery module is higher than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, the input control signal of the third power MOSFET switch Q3 is set to a high level, the third power MOSFET switch Q3 conducts, the first battery module and the second battery module discharge, and the second energy storage inductor L2 stores energy. When the state of charge of the first battery module and the second battery module is less than the average value of the state of charge of the first battery module, the second battery module, and the third battery module, the input control signal of the third power MOSFET switch Q3 is set to a low level, then the fourth power MOSFET switch Q4 conducts, the third battery module discharges, and the second energy storage inductor L2 stores energy.

[0031] When the state of charge of the first battery module and the second battery module is equal to the average value of the state of charge of the first battery module, the second battery module, and the third battery module, the third power MOSFET switch Q3 and the fourth power MOSFET switch Q4 are turned off.

[0032] As Figure 6 shown in (a), when the control signal input to the equalization control system reaches a high level, Q1 will conduct. Then, the first battery module discharges through the marking loop, and the marking loop consists of the first battery module, Q1, and L2. During this period, the current increases from zero, and at the same time, electrical energy is converted into magnetic energy and stored in the inductor L2. After that, when the control signal turns to a low voltage, it causes Q1 to turn off, releasing the magnetic energy in L2 and converting it back into electrical energy. During this period, the current decreases, and the second battery module is charged. These two cycles constitute a switching cycle, and its time length and duty cycle both depend on the control signal. Similarly, energy can be transferred from the second battery module to the first battery module by controlling Q2, as Figure 6 shown in (b). That is, only one switch needs to be controlled to transfer energy between adjacent battery cells once.

[0033] As Figure 7 shown, it shows the working principle of the equalization unit during the equalization process. According to the comparison results of the state of charge of the three batteries, it is divided into four different situations. As Figure 7 shown in (a), if the state of charge of the first battery module is higher than the average value of the state of charge of the three batteries, the input control signal of Q1 is set to a high level, then Q1 conducts, the first battery module discharges, and L1 stores energy. When the state of charge is equal to the average state of charge, the input control signal Q1 is set to a low level, and Q1 is turned off. On the contrary, as Figure 7For the situation shown in (b), if the state of charge of the first battery module is less than the average of the state of charge of the three batteries, the input control signal of Q1 is set to low level, then Q2 conducts, and the second and third battery modules discharge while L1 stores energy. When the state of charge is equal to the average state of charge, the input control signal of Q2 is set to low level to turn off Q2. As Figure 7 For the situation shown in (c), if the state of charge of the first and second battery modules is higher than the average of the state of charge of the three batteries, the input control signal of Q3 is set to high level, then Q3 conducts, and the first and second battery modules discharge while L2 stores energy. When the state of charge is equal to the average state of charge, the input control signal of Q3 is set to low level to turn off Q3. On the contrary, if the state of charge of the first and second battery modules is less than the average of the state of charge of the three batteries, the input control signal of Q3 is set to low level, then Q4 conducts, and the third battery module discharges while L2 stores energy. When the state of charge is equal to the average state of charge, the input control signal of Q4 is set to low level to turn off Q4.

[0034] Since one module consists of three battery cells, the judgment condition is no longer the comparison of adjacent battery cells, but the comparison of the SOC of each battery cell with the average of the three battery cells. According to the difference between the SOC of each battery and the average value, Q1 to Q4 can be operated separately to achieve consistency as soon as possible. Determined by the circuit structure itself, only two of the four MOSFET switches are allowed to operate simultaneously. To prevent the occurrence of some similar foreseeable faults or "over - equalization", the operating conditions of the MOSFET switches must be strictly restricted. A certain threshold must be set and the corresponding control strategy designed. Set the threshold according to the required accuracy of equalization. The higher the accuracy, the smaller the threshold and the longer the required equalization time.

[0035] Since the working principle of the second layer is the same as that of the boost - buck topology, the control method is also the same. Based on obtaining the average state - of - charge values of each module, a simple control method can be formulated to equalize each module.

[0036] Referring to the concepts of mean and maximum difference in statistics, the maximum difference between the SOC values of the three unit batteries and the mean is used as an index for evaluating inconsistency. Adjust the sensitivity of the system by changing the threshold of the maximum difference. The overall operation principle is to perform the first - layer equalization on the basis of the second - layer equalization, and the two can be carried out simultaneously to shorten the time. However, for the proposed two - layer equalization circuit, the second - layer equalization of the topology needs to be completed before the end of the first - layer equalization. If the second - layer equalization is still in progress while the first - layer equalization stops, the local equalization state may change, resulting in the re - expansion of inconsistency. For the three different states of the battery pack, namely static, charging, and discharging, only the determination conditions for the start and end of the equalization action need to be correspondingly restricted at the selected switching period and duty cycle.

[0037] (1)Stationary and charging: The SOC threshold of the second - layer equalization battery is set to 0.02, and the threshold of the first - layer equalization module is set to 0.01.

[0038] (2)Discharging: Considering that the battery is in a discharging state and the randomness of current change is very large, which is likely to cause over - equalization, the equalization threshold should be increased accordingly. In the second - layer equalization, the threshold is set to 0.04, while in the first - layer equalization, the threshold is set to 0.02.

[0039] The above - mentioned strategy is that the SOC between modules should be completed before the cells. Therefore, the threshold voltage of the second layer should be greater than that of the first layer. Considering the accuracy requirements and the sampling ability of the actual circuit, two significant figures are retained. The threshold voltage of the first layer is set to 0.01V, and the threshold voltage of the second layer is set to 0.02V.

[0040] The established overall working principle is as Figure 8 shown, which is reflected in the form of a block diagram. When the calculated SOC difference is not within the set threshold range, the equalization operation exits. To ensure the stability of the second - layer equalization, both the first - layer and second - layer equalizations are carried out simultaneously in the control strategy (i.e., the first - layer equalization and the second - layer equalization work simultaneously), and the threshold is set to ensure that the second layer is completed before the first layer, thus avoiding conflicts between the two layers and preventing the equalization from falling into an infinite loop.

[0041] To verify the effectiveness of the proposed topology, a model was constructed in MATLAB software, as Figure 9 shown. Combining the above - mentioned analysis, the equalization circuit and its control module can be modeled and work together based on the Simscape module, and the system modeling can be achieved. Compared with the traditional equalization topology, the most important feature of the proposed equalization topology lies in the structure of the equalization unit, which consists of three battery cells. Therefore, more attention should be paid to the working characteristics of this equalization unit in this simulation.

[0042] Figure 10 This is a typical simulation result of the equalization process in the stationary state. When the maximum difference in SOC is less than 1%, it can be considered as equalized. When the maximum difference in the initial state of charge value is less than 10%, equalization can be achieved within 500s, and different initial states of charge of the battery will not cause changes in the equalization speed. On the contrary, if the traditional buck - boost topology is used for equalization, the equalization time spent within the same current limit is usually about 600s, as Figure 11 shown.

[0043] Meanwhile, the charge and discharge states of the battery during the UDDS (urban dynamometer driving schedule) cycle are introduced into the simulation of the two equalization circuits for dynamic performance comparison. The SOC extreme value differences between the two equalization methods are as Figure 12 shown. The results show that the two-layer equalization topology proposed in this paper can achieve faster battery equalization with fewer devices during the operation of electric vehicles.

[0044] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic. The software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design software. Those of ordinary skill in the art can understand that the above devices and methods can be implemented using computer-executable instructions and / or included in processor control code, such as provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits of programmable hardware devices such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above hardware circuits and software such as firmware.

[0045] The advantages and positive effects of the technical solution to be protected by the present invention are as follows: First, the buck-boost converter widely used in power electronics technology is transformed into a buck-boost equalization topology in the present invention, and the structure and equalization strategy are optimized, thereby reducing the time cost and economic cost. The purpose of the present invention is to solve the problem of inconsistency of lithium battery packs in new energy energy storage systems. Through equalization control, the influence caused by natural inconsistencies caused by production conditions and working environments can be minimized as much as possible, such as: battery capacity decline, battery life shortening, or even damage.

[0046] After the technical solution of the present invention is transformed, it can be applied to the problem of inconsistency of energy storage lithium batteries in new energy energy storage systems. To a certain extent, it can solve problems such as battery capacity decline, battery life shortening, or even damage caused by long-term inconsistency of battery packs.

[0047] Second, the present invention proposes an equalization method for an improved two-layer buck-boost equalization topology. Compared with traditional optimization methods, the advantages of the present invention are: achieving a breakthrough in having a faster equalization speed than the traditional two-layer buck-boost equalization topology with fewer components, that is, at a lower cost.

[0048] Third, the expected benefits and commercial value after the transformation of the technical solution of the present invention are as follows: optimizing the balancing performance of the energy storage lithium battery equalization topology, enhancing the safety of the system, and reducing the possibility of problems such as performance degradation and damage of lithium batteries caused by the long-term inconsistency of lithium battery packs in the energy storage system. This will reduce the costs of lithium battery repair or replacement and the consumed time costs. The commercial value of the equalization method for new energy storage batteries of power electronic converters is reflected in multiple aspects such as technical advantages, market competitiveness, product quality improvement, cost and time savings. Such a technical solution can enhance the innovation ability of enterprises and gain a better position and return for them in the market.

[0049] Does the technical solution of the present invention overcome technical prejudice: The equalization technology for new energy storage batteries based on power electronic converters does not directly involve the issue of overcoming technical prejudice. Using the equalization technology for new energy storage batteries based on power electronic converters is a tool and method to help engineers and researchers better understand the equalization circuit, optimize the design, and solve potential inconsistencies of energy storage lithium batteries. This technology does not overcome prejudice, but provides a means for engineers and researchers to analyze and optimize the equalization circuit. It can help engineers more comprehensively consider the problem of battery pack inconsistency, optimize the design, and improve product quality and reliability.

[0050] Fourth, the significant technological progress of the equalization method provided by the present invention is mainly reflected in the following aspects: Using the equalization topology design method provided by the present invention, the equalization speed can be increased, the equalization cost can be reduced, and the stability and reliability of lithium batteries can be improved.

[0051] Adopting the improved double-layer buck-boost equalization topology circuit can improve the equalization efficiency, reduce energy loss, and improve the performance and life of lithium battery packs.

[0052] The technological progress of the optimization method provided by the present invention can not only enhance product performance, but also help enterprises reduce production costs and enhance market competitiveness.

[0053] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A balancing topology circuit for a new energy storage battery, characterized in that, Including: A multi-level single-stage buck-boost equalization topology, where adjacent single-stage buck-boost equalization topologies are connected by an additional energy storage inductor, an additional power MOSFET switch and its additional body diode; The single-stage buck-boost equalization topology includes: a first energy storage inductor, a second energy storage inductor, a first power MOSFET switch and its first body diode, a second power MOSFET switch and its second body diode, a third power MOSFET switch and its third body diode, a fourth power MOSFET switch and its fourth body diode, a first battery module, a second battery module and a third battery module; The drain of the first power MOSFET switch is connected to the positive electrode of the first battery module and the drain of the third power MOSFET switch, and the gate of the first power MOSFET switch is connected to the drain of the second power MOSFET switch and one end of the first energy storage inductor; the other end of the first energy storage inductor is connected to the negative electrode of the first battery module and the positive electrode of the second battery module; The drain of the second power MOSFET switch is connected to the negative electrode of the third battery module and the source of the fourth power MOSFET switch, and the positive electrode of the third battery module is connected to the negative electrode of the second battery module and one end of the second energy storage inductor; the other end of the second energy storage inductor is connected to the source of the third power MOSFET switch and the drain of the fourth power MOSFET switch.

2. The equalization topology circuit of a new energy storage battery as described in claim 1, wherein The drain of the additional power MOSFET switch is connected to the drain of the third power MOSFET switch, the source of the additional power MOSFET switch is connected to the drain of the adjacent additional power MOSFET switch and one end of the additional energy storage inductor, and the other end of the additional energy storage inductor is connected to the adjacent single-stage buck-boost equalization topology.

3. The equalization topology circuit of a new energy storage battery as described in claim 2, wherein The positive electrode of the additional body diode is connected to the source of the additional power MOSFET switch, and the negative electrode of the additional body diode is connected to the drain of the additional power MOSFET switch.

4. The equalization topology circuit of a new energy storage battery according to claim 1, characterized in that, The positive electrode of the first body diode is connected to the source of the first power MOSFET switch, and the negative electrode of the first body diode is connected to the drain of the first power MOSFET switch; The positive electrode of the second body diode is connected to the source of the second power MOSFET switch, and the negative electrode of the second body diode is connected to the drain of the second power MOSFET switch; The positive electrode of the third body diode is connected to the source of the third power MOSFET switch, and the negative electrode of the third body diode is connected to the drain of the third power MOSFET switch; The positive electrode of the fourth body diode is connected to the source of the fourth power MOSFET switch, and the negative electrode of the fourth body diode is connected to the drain of the fourth power MOSFET switch.

5. A control method for an equalization topology circuit of a new energy energy storage battery according to any one of claims 1-4, characterized in that, Including: Obtain the state of charge of the first battery module, the state of charge of the second battery module and the state of charge of the third battery module, and calculate the average value of the state of charge of the first battery module, the second battery module and the third battery module; Compare the state of charge of each battery module with the average value respectively, and control the on / off states of each component in the equalization topology circuit according to the comparison results.

6. The control method of the equalization topology circuit of a new energy storage battery according to claim 5, characterized in that, The control of the on / off states of each component in the equalization topology circuit according to the comparison results includes: When the state of charge of the first battery module is higher than the average value of the states of charge of the first, second, and third battery modules, set the input control signal of the first power MOSFET switch to high level, the first power MOSFET switch conducts, the first battery module discharges, and the first energy storage inductor stores energy; when the state of charge of the first battery module is less than the average value of the states of charge of the first, second, and third battery modules, set the input control signal of the first power MOSFET switch to low level, the second power MOSFET switch conducts, the second and third battery modules discharge, and the first energy storage inductor stores energy; When the state of charge is equal to the average state of charge, set the input control signal of the first power MOSFET switch to low level and turn off the first power MOSFET switch; after the first power MOSFET switch is turned off, the first energy storage inductor, the second battery module, the third battery module, and the second body diode form a loop, and the current gradually decreases to zero, and the energy stored in the first energy storage inductor is released and reconverted into electrical energy; set the input control signal of the second power MOSFET switch to low level and turn off the second power MOSFET switch; When the states of charge of the first and second battery modules are higher than the average value of the states of charge of the first, second, and third battery modules, set the input control signal of the third power MOSFET switch to high level, the third power MOSFET switch conducts, the first and second battery modules discharge, and the second energy storage inductor stores energy; when the states of charge of the first and second battery modules are less than the average value of the states of charge of the first, second, and third battery modules, set the input control signal of the third power MOSFET switch to low level, and then the fourth power MOSFET switch conducts, the third battery module discharges, and the second energy storage inductor stores energy; When the states of charge of the first and second battery modules are equal to the average value of the states of charge of the first, second, and third battery modules, turn off the third and fourth power MOSFET switches.

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