Energy storage system and balance management strategy thereof

Abstract

The invention discloses an energy storage system and an equalization management strategy thereof, and belongs to the technical field of new energy storage and power generation, and the system comprises a bidirectional energy storage converter, a bidirectional DC converter, a power supply management and control unit, a battery management high-voltage box and a battery system. One end of the bidirectional energy storage converter is externally connected with a load or grid-connected alternating current, the other end of the bidirectional energy storage converter is in bidirectional connection with one end of the bidirectional direct current converter, and the other end of the bidirectional direct current converter is in bidirectional connection with multiple groups of lines of the battery management high-voltage box; the other end of the battery management high-voltage box is bidirectionally connected with a battery system through a plurality of groups of lines, and the power supply management and control unit is in bidirectional communication connection with the bidirectional energy storage converter, the bidirectional direct-current converter and the battery management high-voltage box. According to the energy storage system with a distributed structure, multi-channel independent charging and discharging control is carried out on the battery system through a plurality of mutually independent channels, and rapid energy storage balance between battery packs is realized.

Description

Technical Field

[0001] The present invention relates to the field of new energy storage and power generation technology, and in particular to an energy storage system and a balanced management strategy thereof. Background Art

[0002] Lithium batteries are crucial as energy storage vessels, and different disciplines and industry chains focus on different issues and solve different technical challenges. Materials scientists focus on the performance and material quality of lithium battery cells; systems integrators focus on the relationships between lithium batteries, such as the relationships between battery modules, battery packs, and battery systems. Since these are all composed of battery cells connected in series and parallel, there are differences and consistency issues. These issues lead to reduced system charge and discharge capacity, shortened lifespan, and reduced safety. To address these issues, cell screening is the foundation, assembly process is the key, and balancing is the primary guarantee.

[0003] Existing balancing technologies include active balancing and passive balancing. Due to limitations in technology, devices, heat dissipation, etc., existing technologies can only solve the problem of local differences in lithium batteries with low consistency. For large-scale and complex energy storage systems, traditional balancing technologies cannot solve the differences in battery packs.

[0004] Therefore, there is an urgent need for an energy storage system and its balancing management strategy that can solve the technical problem in the existing technology that it is impossible to accurately balance the large differences in energy storage within a complex power system. Summary of the Invention

[0005] In view of this, it is necessary to provide an energy storage system and its balancing management strategy to achieve energy balance within a complex power system.

[0006] In order to solve the above technical problems, on the one hand, the present invention provides an energy storage system, comprising: a bidirectional energy storage converter, a bidirectional DC converter, a power supply management and control unit, a battery management high-voltage box and a battery system; One end of the bidirectional energy storage inverter is connected to an external load or grid-connected AC power, and the other end is bidirectionally connected to one end of the bidirectional DC converter. The other end of the bidirectional DC converter is bidirectionally connected to multiple groups of lines of the battery management high-voltage box. The other end of the battery management high-voltage box is bidirectionally connected to the battery system through multiple groups of lines. The power supply management and control unit is bidirectionally communicatively connected to the bidirectional energy storage inverter, bidirectional DC converter and battery management high-voltage box.

[0007] In one possible implementation, the bidirectional energy storage converter is used to convert internal direct current into alternating current to output electrical energy externally, or to convert external alternating current into direct current to input into the bidirectional direct current converter.

[0008] In one possible implementation, the bidirectional DC converter includes a plurality of DC conversion channels; The bidirectional DC converter is used to receive DC power output from the battery system through multiple DC conversion channels, convert the DC power into DC power of different voltage values ​​and output it to the bidirectional energy storage converter, or convert the DC voltage input to the bidirectional energy storage converter into a DC voltage for the battery system to operate, and input it to the battery system through multiple DC conversion channels, and each of the DC conversion channels is independently controlled.

[0009] In one possible implementation, the power management and control unit includes a human-computer interaction device, a master controller, a battery, a DC power supply, and a charging module; The human-computer interaction device is used to send control instructions and receive and display the status of the energy storage system; The master controller is used to receive communication information from the bidirectional energy storage converter, the bidirectional DC converter, the battery management high-voltage box, and the battery system, and control the input or output of electric energy according to the energy management strategy; The battery is used to provide starting power for the energy storage battery system, is charged by the charging module, and outputs control power to the outside through the DC power supply; The charging module is used to convert the electric energy of the battery management high-voltage box into low-voltage electric energy to charge the battery; The DC power supply is used to convert the battery power into control power, providing control power for the human-computer interaction device, main controller, bidirectional energy storage converter, bidirectional DC converter, battery management high-voltage box and battery system.

[0010] In one possible implementation, the battery system includes a plurality of parallel battery packs and a plurality of battery pack connection cables; the battery packs are bidirectionally connected to the battery management high-voltage box via the battery pack connection cables in a multi-channel manner; The battery pack includes a plurality of battery modules connected in series; The battery module includes a plurality of battery module units connected in series and a slave control board; The battery module unit includes a battery module, an energy consumption resistor and a switch component; the energy consumption resistor and the switch component are connected in series and then in parallel with the battery module; The battery module includes a plurality of battery cells connected in parallel; The external interfaces of the battery module include positive and negative electrode interfaces, charging interfaces, and communication and control interfaces; The battery pack connection cable includes positive and negative pole lines, a charging line, a control line and a communication line. A plurality of aviation plug interfaces are connected in series in the middle of the battery pack cable. The battery modules are connected in series through the aviation plug interfaces. The aviation plug interfaces include positive and negative pole interfaces, a charging interface, and a communication and control interface.

[0011] In one possible implementation, the battery management high-voltage box includes a plurality of battery management channels, a plurality of channel cables, and a system control board; The battery management channel includes a main control board, a contactor, a unidirectional conductive component, and a battery pack charging module; One end of the contactor is connected to the battery pack in a one-to-one correspondence, and the other end is connected to the DC conversion channel of the bidirectional DC converter in a one-to-one correspondence. The main control board is connected to the contactor for controlling the on and off of the contactor to form a main circuit; The input end of the one-way conducting component is connected to the battery pack in a one-to-one correspondence, and is used to output the electric energy of the battery pack in a one-way direction. Multiple one-way conducting components are connected in parallel to output the electric energy of multiple battery packs in a one-way direction. The power input end of the battery pack charging module is connected to the output end of the unidirectional conductive component, and the power output end of the battery pack charging module is connected to the battery pack in a one-to-one correspondence; The main control board is used to communicate and receive status information of each battery module in the corresponding battery pack and the system control information, and generate main control information according to the status information and the system control information; The channel cable includes the positive and negative lines of the main circuit, the charging line of the battery pack charging module, the control line and the communication line of the main controller. These lines are combined into a channel cable, and one battery management channel corresponds to one channel cable; The channel cables are correspondingly connected to the battery pack connection cables; The system control board receives status information of each battery pack through the main control board, generates system control information based on the status information, and sends the status information to the power management and control unit, and sends the control information to the main control board; In a second aspect, the present invention further provides a balancing management strategy, based on the above energy storage system, including: a battery module energy consumption balancing management strategy, a battery pack charging balancing management strategy and an energy storage system charge and discharge balancing management strategy.

[0012] In one possible implementation, the battery module energy consumption balancing management strategy includes: During the non-charging and discharging process, each slave control board obtains the voltage of each battery module in the corresponding battery pack, and determines the battery module voltage target value according to the voltage of each battery module; The voltage value of each battery module is compared with the target value. When the difference exceeds a first preset threshold, the slave control board controls the switch component to connect, the energy consumption resistor is connected in parallel with the battery module, and the energy consumption resistor discharges to consume the power of the battery module.

[0013] In one possible implementation, the battery pack charge balancing management strategy includes: During non-charging or non-discharging or charging processes, each of the main control boards obtains information about each battery module in the corresponding battery pack, including the state of charge of the battery modules, and determines the state of charge of the highest battery module as the target state of charge of the battery module; The difference between the state of charge of each battery module in the battery pack and the target value is determined in sequence. When the difference exceeds a second preset threshold, the main control board generates charging control information for the corresponding module, and the main control board uses a polling mode to charge the corresponding battery module one by one; The slave control board receives the charging control information sent from the master control board, and controls the charging module to charge the corresponding battery module.

[0014] In one possible implementation, the energy storage system charge and discharge balance management strategy includes: During the charging and discharging process, the system control board receives the state of charge of each battery pack and determines the target value of the state of charge of the battery pack; sequentially determining a difference between the state of charge of each battery pack and a target state of charge value of the battery pack, and generating a charge and discharge current control signal when the difference exceeds a third preset threshold; The system control board sends the charge and discharge current control signal to the bidirectional DC converter through the battery management and control unit; the bidirectional DC converter independently adjusts the electric energy input or output power of the corresponding DC conversion channel.

[0015] The beneficial effects of the present invention are as follows: by setting up a bidirectional energy storage converter, a bidirectional DC converter, a power supply control unit, a battery management high-voltage box and a battery system, an energy storage system capable of achieving automatic energy storage balancing is constructed; wherein, one end of the bidirectional energy storage converter is externally connected to a load or grid-connected AC power, and the other end is bidirectionally connected to one end of the bidirectional DC converter, the other end of the bidirectional DC converter is bidirectionally connected to multiple groups of lines of the battery management high-voltage box, the other end of the battery management high-voltage box is bidirectionally connected to the battery system through multiple groups of lines, the power supply control unit is bidirectionally connected to the bidirectional energy storage converter, the bidirectional DC converter and the battery management high-voltage box, and the battery system is divided into multiple independent charge and discharge channels through the multi-channel DC converter, the battery high-voltage box and the battery system, and the charge and discharge control of the independent channels is performed. The present invention realizes energy storage balancing between battery groups through a distributed structure energy storage system and a multi-channel independent charge and discharge control and balancing strategy for the battery system through multiple independent channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic structural diagram of an embodiment of the energy storage system provided by the present invention; Figure 2 A schematic structural diagram of an embodiment of a battery module provided by the present invention; Figure 3 A schematic structural diagram of an embodiment of a battery management high-voltage box provided by the present invention; Figure 4 A flow chart of an embodiment of the battery module energy consumption balancing management strategy provided by the present invention; Figure 5 A flow chart of an embodiment of a battery pack charge balancing management strategy provided by the present invention; Figure 6 This is a flow chart of an embodiment of the charge-discharge balance management strategy for the energy storage system provided by the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present invention, unless otherwise specified, “a plurality of” means two or more.

[0020] The terms "first," "second," and so on, used in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature designated as "first" or "second" may explicitly or implicitly include at least one such feature.

[0021] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] The present invention provides an energy storage system and a balanced management strategy thereof, which are described below.

[0023] Figure 1 A schematic flow chart of an embodiment of the energy storage system provided by the present invention is shown as follows: Figure 1 As shown, the energy storage system includes: a bidirectional energy storage converter 100, a bidirectional DC converter 200, a power supply management and control unit 300, a battery management high-voltage box 400 and a battery system 500; One end of the bidirectional energy storage inverter 100 is connected to an external load or grid-connected AC power, and the other end is bidirectionally connected to one end of the bidirectional DC converter 200. The other end of the bidirectional DC converter 200 is bidirectionally connected to multiple groups of lines of the battery management high-voltage box 400. The other end of the battery management high-voltage box 400 is bidirectionally connected to the battery system 500 through multiple groups of lines. The power supply management and control unit 300 is bidirectionally communicatively connected to the bidirectional energy storage inverter 100, the bidirectional DC converter 200 and the battery management high-voltage box 400.

[0024] It should be noted that the energy storage system in this example is applied to various large-scale power supply systems to provide power for electrical equipment. The energy storage system collects and monitors the charging and discharging parameter data of each battery group 510 through the battery management high-voltage box 400, and realizes energy balance from battery group to battery pack by analyzing the acquired data.

[0025] This embodiment constructs an energy storage system capable of achieving automatic energy balancing by providing a bidirectional energy storage converter 100, a bidirectional DC converter 200, a power management unit 300, a battery management high-voltage box 400, and a battery system 500. One end of the bidirectional energy storage converter 100 is connected to an external load or grid-connected AC power, and the other end is bidirectionally connected to one end of the bidirectional DC converter 200. The other end of the bidirectional DC converter 200 is bidirectionally connected to multiple groups of lines of the battery management high-voltage box 400. The other end of the battery management high-voltage box 400 is bidirectionally connected to the battery system 500 via multiple groups of lines. The power management unit 300 is bidirectionally connected to the bidirectional energy storage converter 100, the bidirectional DC converter 200, and the battery management high-voltage box 400. Through the multi-channel DC converter, the battery high-voltage box 400, and the battery system 500, the battery system 500 is divided into multiple independent charging and discharging channels, and charging and discharging of the independent channels are controlled. This embodiment uses a distributed energy storage system to perform multi-channel independent charge and discharge control and balance on the battery system 500 through multiple independent channels, thereby achieving energy storage balance among battery groups.

[0026] In some embodiments of the present invention, the bidirectional energy storage converter 100 is used to convert internal DC power into AC power for external output, or to convert external AC power into DC power for input into the bidirectional DC converter 200 .

[0027] Specifically, during the discharge process of the energy storage system, the bidirectional energy storage converter 100 converts the DC power inside the energy storage system into AC power output. During the charging process, the bidirectional energy storage converter 100 converts the external three-phase AC power or single-phase AC power into DC power to charge the internal power. The AC power can be three-phase AC power or single-phase AC power, and the AC power output can be an independent output interface or a grid-connected output interface.

[0028] Furthermore, in this embodiment, the power range of the bidirectional energy storage converter 100 is 10-1000kW, the DC side voltage range is DC650-750V, and the AC side voltage is three-phase AC400V (1±10%), or single-phase AC230V (1±10%). The bidirectional energy storage converter 100 converts the internal DC650-750V into three-phase AC400V, and the three-phase imbalance is greater than 50%. It can output single-phase AC230V for use. The output power can be used independently with three-phase loads or single-phase loads, and can also be used in conjunction with the mains or other power sources, and output three-phase power or single-phase power in conjunction with the grid; the three-phase AC400V or single-phase AC400V of the grid-connected port is converted by the bidirectional energy storage converter 100. The 230V AC power is converted into DC power of DC650-750V for internal charging. For example, when the bidirectional energy storage converter has a power of 50kW, a DC side voltage range of DC650-750V, and an AC side voltage of three-phase AC400V or single-phase AC230V, when the bidirectional energy storage converter 100 outputs power externally, it outputs 50kW of three-phase AC400V power and 25kW of single-phase AC230V power. This can be output independently or in conjunction with the grid. The bidirectional energy storage converter 100 inputs power internally, converting the 50kW of three-phase AC400V power or 25kW of single-phase AC230V power from the grid-connected port into DC power of DC650-750V for internal charging.

[0029] In some embodiments of the present invention, the bidirectional DC converter 200 includes a plurality of DC conversion channels; The bidirectional DC converter 200 is used to receive DC power output from the battery system 500 through multiple DC conversion channels, convert the DC power into high-voltage DC power and output it to the bidirectional energy storage converter 100, or convert the DC voltage input to the bidirectional energy storage converter into a DC voltage for the battery system 500 to operate, and input it to the battery system 500 through multiple DC conversion channels. Each DC conversion channel is independently controlled.

[0030] Specifically, one end of the bidirectional DC converter 200 is the high-voltage side, and the other end is the low-voltage side. The low-voltage side is a plurality of DC conversion channel ports, and each DC conversion channel is independently controlled. The low-voltage side of the bidirectional DC converter 200 is a plurality of bidirectional DC conversion channels, and the high-voltage side is merged into one channel. During the charging process, the bidirectional DC converter 200 converts the high-voltage DC power output by the bidirectional energy storage converter 100 into a plurality of channels of low-voltage DC power to control the input of electrical energy. During the discharging process, the bidirectional DC converter 200 converts the low-voltage DC power output by the battery pack 510 into high-voltage DC power, and connects them in parallel to control the output of electrical energy.

[0031] Furthermore, in this embodiment, the bidirectional DC converter 200 has a power range of 10-1000kW, a high-voltage DC side voltage range of DC650-750V, a low-voltage side voltage range of DC40-250V, 2 to 20 DC conversion channels, each channel independently controlled, and a power range of 5-50kW; the DC power supply is independent on the low-voltage side and combined on the high-voltage side; during the discharge process of the energy storage system, the low-voltage side DC40-250V DC voltage is converted into high-voltage side DC650-750V power output; during the charging process of the energy storage system, the high-voltage side DC650-750V DC power is converted into low-voltage side DC40-250V DC power input, and multiple channels are independently controlled to control different low-voltage values ​​and powers. For example, when the bidirectional DC converter 200 has a power of 50kW, the high-voltage DC side voltage range is DC650-750V, the low-voltage DC side voltage range is DC100-148V, and 6 channels are designed, each channel has a power of 9kW. When used, the charging and discharging power of the 6 channels can be adjusted, and the current control accuracy can reach the 1A level.

[0032] In some embodiments of the present invention, the power management and control unit 300 includes a human-computer interaction device, a master controller, a battery, a DC power supply, and a charging module; Human-computer interaction equipment, used to send control commands, receive and display the status of the energy storage system; The master controller is used to receive communication information from the bidirectional energy storage converter 100, the bidirectional DC converter 200, the battery management high-voltage box 400, and the battery system 500, and control the input or output of electric energy according to the energy management strategy; The battery is used to provide starting power for the energy storage battery system 500, charges the battery through the charging module, and outputs control power to the outside through the DC power supply; The charging module is used to convert the unidirectional output power of the battery management high-voltage box 400 into low-voltage power to charge the battery; The DC power supply is used to convert battery power into control power, providing control power for the human-computer interaction device, the main controller, the bidirectional energy storage converter 100, the bidirectional DC converter 200, the battery management high-voltage box 400 and the battery system 500.

[0033] It should be noted that in the human-computer interaction device, human-computer interaction is achieved through a touch screen or computer, and a control panel is used to send control instructions and receive and display the energy storage system status. The main controller is implemented using an embedded controller or a PLC module, the battery is a valve-regulated lead-acid battery, and the DC power supply is a Mingwei DC power supply.

[0034] It should be further noted that in this embodiment, the power management and control unit 300 comprises a 12-inch touch screen, a control panel including start, stop, and emergency stop buttons, an audible and visual alarm indicator, a Siemens PLC, a 24V DC battery, a Mingwei DC regulated power supply (input range: 18-32V DC, output: 24V DC), and a Mingwei charging module (input: 100-200V DC, output: 18-32V DC). Manual start and stop control is possible, and the touch screen displays detailed status information and saves it in real time.

[0035] In some embodiments of the present invention, the battery system 500 includes a plurality of parallel battery packs 510 and a plurality of battery pack connection cables; the battery packs 510 are bidirectionally connected to the multi-channel cable of the battery management high-voltage box via the battery pack connection cables; The battery pack 510 includes a plurality of battery modules 511 connected in series; The battery module 511 includes a plurality of battery module units 51110 connected in series and a slave control board; The battery module unit 51110 includes a battery module 51111, an energy dissipation resistor 51112, and a switch component 51113. The energy dissipation resistor 51112 and the switch component 51113 are connected in series and then in parallel with the battery module 51111. The battery module 51111 includes a plurality of battery cells connected in parallel; The external interfaces of the battery module 511 include positive and negative electrode interfaces, charging interfaces, and communication and control interfaces; The battery pack connection cable includes positive and negative pole lines, charging lines, control lines and communication lines. Multiple aviation plug interfaces are connected in series in the middle of the battery pack cable. The battery modules 511 are connected in series through the aviation plug interfaces. The aviation plug interfaces include positive and negative pole interfaces, charging interfaces, and communication and control interfaces.

[0036] Specifically, if Figure 2 As shown, Figure 2 This is a schematic structural diagram of an embodiment of a battery module provided by the present invention.

[0037] It should be noted that there is no restriction on the type of battery cell. In this embodiment, lithium iron phosphate battery cells, ternary battery cells, or ternary high nickel battery cells can be selected. The model can be standard sizes such as INR18650, IFR26650, or IFR4680, or customized square shell batteries.

[0038] It should be further explained that multiple battery cells are connected in parallel to form a battery module 51111, and multiple battery modules 51111 are connected in series to form a battery module 511, and each battery module 51111 is connected in parallel with an energy-consuming resistor 51112; the battery module 51111 can have 2 to 20 battery cells, and then 2 to 10 battery modules 51111 are connected in series to form a battery module 511, and the battery module 511 has a positive and negative electrode interface, a charging interface, and 6 cables (4 of which form a BCD code selection address and 2 for CAN communication); the battery pack 510 is composed of 2 to 16 battery modules 511 connected in series through battery pack connecting cables; the battery system 500 is composed of 2 to 20 battery packs 510 connected in parallel.

[0039] It should be further explained that, in this embodiment, the lithium iron phosphate battery cell IFR26650 is selected, with a rated voltage of DC3.2V, a usage range of DC2.5~3.7V, and a rated current of 3800mA; the battery module is composed of 16 battery cells in parallel, and 4 battery modules are connected in series to form a battery module, with a battery module voltage range of DC10-14.8V, a current of 60.8Ah, and an electric energy of 780Wh; the battery pack is composed of 10 battery modules in series, with a voltage range of DC100-148V, a current of 60.8Ah, and an electric energy of 7800Wh; the battery system is composed of 6 battery packs in parallel, with a voltage range of DC100-148V, a current of 364.8Ah, and a total electric energy of 46.8kWh.

[0040] In some embodiments of the present invention, Figure 3 As shown, Figure 3 This is a structural diagram of an embodiment of a battery management high-voltage box provided by the present invention. The battery management high-voltage box 400 includes a system control board 410, multiple battery management channels 420, and multiple channel cables; The battery management channel 420 includes a main control board 421, a contactor 422, a one-way conducting component 423, and a battery pack charging module 424; One end of the contactor 422 is connected to the battery pack 510 in a one-to-one correspondence, and the other end is connected to the DC conversion channel of the bidirectional DC converter 200 in a one-to-one correspondence. The main control board 421 is connected to the contactor 422 for controlling the on and off of the contactor 422 to form a main circuit; The input end of the unidirectional conductive component 423 is connected to the battery pack 510 in a one-to-one correspondence, and is used to output the power of the battery pack 510 in a unidirectional manner. Multiple unidirectional conductive components 423 are connected in parallel to output the power of multiple battery packs 510 in a unidirectional manner. The power input terminal of the battery pack charging module 424 is connected to the output terminal of the unidirectional conductive component 423, and the power output terminal of the battery pack charging module 424 is connected to the battery pack 510 in a one-to-one correspondence; The main control board 421 is used to communicate and receive status information and system control information of each battery module 511 in the corresponding battery pack 510, and generate main control information based on the status information and system control information; The channel cable includes the positive and negative lines of the main circuit, the charging line of the battery pack charging module, and the control line and communication line of the main controller. These lines are combined into a channel cable, and one battery management channel corresponds to one channel cable; The channel cables are correspondingly connected to the battery pack connection cables; The system control board 410 is used to communicate and receive status information of each battery pack 510, generate system control information based on the status information, and communicate the status information to the power management and control unit 300, and send control information to the main control board 421; It should be noted that the battery management high-voltage box includes an embedded control board, 2 to 10 battery management channels, and 2 to 10 cables. The power of the battery management high-voltage box is 10-1000kW, with a single channel capable of handling 2-50kW. The number of battery management channels and cables should be consistent with the number of battery packs. In this embodiment, the battery management high-voltage box preferably includes an embedded control board (developed with a DSP, ARM, or other embedded chip), 6 battery management channels, and 6 channel cables. The power of the battery management high-voltage box is 50kW, with a single channel capable of handling 9kW.

[0041] Specifically, after the energy storage system is powered on, the battery packs within the battery system are interconnected and connected in series with the battery management high-voltage box. The unidirectional conductive components are connected to the circuit and operate to output electrical energy. Depending on the voltage state of the battery pack, multiple unidirectional conductive components compete for or simultaneously output electrical energy. Some of this output electrical energy is used by the internal charging module to charge the battery modules within the battery pack, while some is output to the power management unit to charge the battery through the charging module or converted back into control power through the DC power supply.

[0042] In some embodiments of the present invention, the balancing management strategy includes a battery module energy consumption balancing management strategy, a battery pack charge balancing management strategy, and an energy storage system charge and discharge balancing management strategy.

[0043] In some embodiments of the present invention, Figure 4 As shown, Figure 4 A flowchart of an embodiment of the battery module energy consumption balancing management strategy provided by the present invention includes: S401. During a non-charging / discharging process, each slave control board obtains the voltage of each battery module in the corresponding battery pack, and determines a target battery module voltage value based on the voltage of each battery module; S401. Compare the voltage value of each battery module with the target value. When the difference exceeds a first preset threshold, control the switch component from the control board to connect, connect the energy dissipation resistor in parallel with the battery module, and discharge the energy dissipation resistor to consume the power of the battery module.

[0044] It should be noted that the energy consumption resistor and the switch component are connected in series to form a battery module energy consumption balancing circuit with the battery module. The discharge of the corresponding battery module is controlled by controlling whether the energy consumption resistor is connected in parallel to the battery module from the control board.

[0045] Specifically, multiple cells are connected in parallel to form a battery module, and multiple battery modules are connected in series to form a battery module. Each battery module is connected in parallel with an energy-dissipating resistor. A battery module can consist of 2 to 20 cells connected in parallel, and a battery module can consist of 2 to 10 battery modules connected in series. Together with the slave control board, the battery module has a designed energy-dissipating resistor value of 3.6 to 0.5 Ω, and the discharge current of the energy-dissipating resistor is controlled within 1 to 5 A. The slave control board monitors the battery module voltage in real time and uses the minimum voltage value of each battery module as the target voltage value. When the slave control board detects that the difference between the battery module voltage and the target voltage value exceeds a first preset threshold, the control switch component connects the energy-dissipating resistor to the battery module for energy balancing management.

[0046] Furthermore, in this embodiment, preferably, the battery module is composed of 64 battery cells, 16 battery cells are connected in parallel to form a battery module, and then 4 battery module strings are used to form a battery module. Each battery module is incorporated with an energy consumption resistor, the energy consumption resistor is 1500 milliohms, and the rated energy consumption current is 2A, which fluctuates by 1.6~2.4A according to the voltage change; the battery module has 4 energy consumption resistors, and the minimum value of the battery module voltage is used as the target value. The battery module voltage value is calculated and compared with the target value. When the difference exceeds 300mV, the energy consumption resistor corresponding to the battery module is controlled to be connected and used to perform energy consumption balancing management. Up to 3 energy consumption resistors can be controlled to work at the same time.

[0047] In some embodiments of the present invention, Figure 5 As shown, Figure 5 This is a flow chart of an embodiment of a battery pack charge balancing management strategy provided by the present invention. The battery pack charge balancing management strategy includes: S501. During non-charging or non-discharging or charging processes, each main control board obtains information about each battery module in the corresponding battery pack, including the state of charge of the battery module, and determines the highest state of charge of the battery module as a target state of charge of the battery module; S502: sequentially determining the difference between the state of charge of each battery module in the battery pack and the target value. When the difference exceeds a second preset threshold, the main control board generates charging control information for the corresponding module, and the main control board uses a polling mode to cyclically charge the corresponding battery module one by one. S503: The slave control board receives the charging control information sent from the main control board, and controls the charging module to charge the corresponding battery module.

[0048] It should be noted that the channel cable includes positive and negative lines, charging lines, control lines, and communication lines. These lines are combined into a channel cable, and one battery management channel corresponds to one channel cable. The charging line in the channel cable is connected in series with the charging line, battery pack charging module, battery module, and charging interface in the battery pack to form a battery pack charging balancing circuit.

[0049] Specifically, when the main control board determines that a battery module needs to be charged, the main control board controls the battery pack charging balancing circuit to start by the slave control board to supplement the charging of the battery module. If there are multiple battery modules in the battery pack that need to be supplemented, the main control board uses a polling mode to charge the battery modules one by one in a cycle to avoid charging a single battery module for too long, ensuring that the power of the battery modules that need to be supplemented is increased synchronously. Multiple battery packs in the battery system can be supplemented and charged synchronously.

[0050] Furthermore, the battery pack consists of 2 to 16 battery modules connected in series. The battery management channel of the battery management high-voltage box is used in series with the battery pack. The battery system consists of 2 to 10 battery packs and the battery management high-voltage box. The main control board communicates with the battery management channel to monitor the battery module voltage, state of charge (SOC), and temperature information in the battery pack. The main control board calculates the target SOC of the battery module and calculates the difference between the SOC of each battery module and the target SOC. When the difference exceeds a second preset threshold, the main control board marks the battery module as requiring charging. If each battery module charges for 1 to 3 minutes and there are 8 battery modules requiring charging, the main control board uses a polling mode to supplement the charging of the 8 battery modules. Using a constant power charging module (e.g., 20 to 200W), the main control board charges the battery modules in descending order of the difference. After each polling cycle, the main control board calculates the module requiring charging again. Multiple battery packs in the battery system can simultaneously perform supplementary charging and balancing management. For example, a battery pack consists of 10 battery modules connected in series, the battery system has 6 battery packs, and the battery management high-voltage box has 6 battery management channels. The main control board in the battery management channel collects the voltage, SOC, and temperature information of the battery modules in the battery pack. Using the maximum SOC of the battery module as the target value, the main control board calculates the difference between the SOC of the other nine battery modules and the target SOC value. If the difference exceeds 2%, supplementary charging is required. For example, if there are four battery modules in the battery pack that need supplementary charging, the main control board uses polling mode to supplementary charge these four battery modules. The charging module power is 100W, and the battery modules are charged in descending order of the difference. Each battery module is charged for one minute. After polling charging, the module that needs charging is calculated again.

[0051] In some embodiments of the present invention, Figure 6 As shown, Figure 6 A flow chart of an embodiment of the energy storage system charge and discharge balance management strategy provided by the present invention includes: S601: During the charge and discharge process, the system control board receives the state of charge of each battery pack and determines a target state of charge value of the battery pack; S602, sequentially determining the difference between the state of charge of each battery pack and a target state of charge value of the battery pack, and generating a charge and discharge current control signal when the difference exceeds a third preset threshold; S603: The system control board sends the charge and discharge current control signal to the bidirectional DC converter via the battery management and control unit; the bidirectional DC converter independently adjusts the power input or output power of the corresponding DC conversion channel.

[0052] It should be noted that the energy storage system charge-discharge balancing management strategy addresses the significant variability among battery packs in a battery system. These variability is difficult to address or requires a long time to address using the previously described battery module energy consumption balancing management strategy and battery pack charge balancing management strategy. The multiple DC conversion channels of the bidirectional DC converter, the multiple battery management channels of the battery management high-voltage box, and the multiple battery packs are connected in series. Each DC conversion channel, battery management channel, and battery pack are connected in series to form a battery pack charge-discharge channel. Each battery pack charge-discharge channel is independent of the others. Energy storage system balancing is achieved by independently regulating and controlling the power input or output of the DC conversion channels of the bidirectional DC converter.

[0053] Specifically, when the state of charge (SOC) of a battery pack in the battery system differs from a target battery pack state of charge (SOC) by more than a third preset threshold, energy balancing is achieved between the battery packs in the energy storage system by independently adjusting and controlling the power input or output of the DC conversion channels of the bidirectional DC converter. In this embodiment, when the state of charge (SOC) of the battery packs in the battery system differs by more than 5%, multiple battery pack charge and discharge channels operate simultaneously during charging. When the battery pack state of charge (SOC) of the channel is higher, the bidirectional DC converter adjusts the input current to be lower, such as 5A lower than the target battery pack charge current value; when the battery pack state of charge (SOC) of the channel is lower, the bidirectional DC converter adjusts the input current to be higher, such as 5A higher than the target battery pack charge current value. The specific value can be calculated using a segmented table lookup method or a fitting formula interpolation method based on the battery pack SOC value and the charge and discharge current value.

[0054] The energy storage system and balancing management strategy provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An energy storage system, characterized in that: include: Bidirectional energy storage converter, bidirectional DC converter, power management and control unit, battery management high-voltage box and battery system; One end of the bidirectional energy storage inverter is connected to external AC power, and the other end is bidirectionally connected to one end of the bidirectional DC converter. The other end of the bidirectional DC converter is bidirectionally connected to multiple groups of lines of the battery management high-voltage box. The other end of the battery management high-voltage box is bidirectionally connected to the battery system through multiple groups of lines. The power supply management and control unit is bidirectionally communicatively connected with the bidirectional energy storage inverter, bidirectional DC converter and battery management high-voltage box.

2. The energy storage system according to claim 1, characterized in that The bidirectional energy storage converter is used to convert internal direct current into alternating current and output electric energy externally, or to convert external alternating current into direct current and input it into the bidirectional direct current converter.

3. The energy storage system according to claim 2, characterized in that: The bidirectional DC converter includes a plurality of DC conversion channels; The bidirectional DC converter is used to receive DC power output from the battery system through multiple DC conversion channels, convert the DC power into DC power of different voltage values ​​and output it to the bidirectional energy storage converter, or convert the DC voltage input to the bidirectional energy storage converter into a DC voltage for the battery system to operate, and input it to the battery system through multiple DC conversion channels, and each of the DC conversion channels is independently controlled.

4. The energy storage system according to claim 1, characterized in that The power management and control unit includes a human-computer interaction device, a main controller, a battery, a DC power supply and a charging module; The human-computer interaction device is used to send control instructions and receive and display the status of the energy storage system; The master controller is used to receive communication information from the bidirectional energy storage converter, the bidirectional DC converter, the battery management high-voltage box, and the battery system, and control the input or output of electric energy according to the energy management strategy; The battery is used to provide starting power for the energy storage battery system, is charged by the charging module, and outputs control power to the outside through the DC power supply; The charging module is used to convert the unidirectional output power of the battery management high-voltage box into low-voltage power to charge the battery; The DC power supply is used to convert the battery power into control power, providing control power for the human-computer interaction device, main controller, bidirectional energy storage converter, bidirectional DC converter, battery management high-voltage box and battery system.

5. The energy storage system according to claim 3, characterized in that: The battery system includes a plurality of parallel battery packs and a plurality of battery pack connection cables; the battery packs are bidirectionally connected to the multi-channel cable of the battery management high-voltage box via the battery pack connection cables; The battery pack includes a plurality of battery modules connected in series; The battery module includes a plurality of battery module units connected in series and a slave control board; The battery module unit includes a battery module, an energy consumption resistor and a switch component; the energy consumption resistor and the switch component are connected in series and then in parallel with the battery module; The battery module includes a plurality of battery cells connected in parallel; The external interfaces of the battery module include positive and negative electrode interfaces, charging interfaces, and communication and control interfaces; The battery pack connection cable includes positive and negative pole lines, a charging line, a control line and a communication line. A plurality of aviation plug interfaces are connected in series in the middle of the battery pack cable. The battery modules are connected in series through the aviation plug interfaces. The aviation plug interfaces include positive and negative pole interfaces, a charging interface, and a communication and control interface.

6. The energy storage system according to claim 5, characterized in that: The battery management high-voltage box includes multiple battery management channels, multiple channel cables and a system control board; The battery management channel includes a main control board, a contactor, a unidirectional conductive component, and a battery pack charging module; One end of the contactor is connected to the battery pack in a one-to-one correspondence, and the other end is connected to the DC conversion channel of the bidirectional DC converter in a one-to-one correspondence. The main control board is connected to the contactor for controlling the on and off of the contactor to form a main circuit; The input end of the one-way conducting component is connected to the battery pack in a one-to-one correspondence, and is used to output the electric energy of the battery pack in a one-way direction. Multiple one-way conducting components are connected in parallel to output the electric energy of multiple battery packs in a one-way direction. The power input end of the battery pack charging module is connected to the output end of the unidirectional conductive component, and the power output end of the battery pack charging module is connected to the battery pack in a one-to-one correspondence; The main control board is used to communicate and receive status information of each battery module in the corresponding battery pack and the system control information, and generate main control information according to the status information and the system control information; The channel cable includes the positive and negative lines of the main circuit, the charging line of the battery pack charging module, the control line and the communication line of the main controller. These lines are combined into a channel cable, and one battery management channel corresponds to one channel cable; The channel cables are correspondingly connected to the battery pack connection cables; The system control board receives status information of each battery pack through communication with the main control board, generates system control information according to the status information, and communicates the status information to the power management and control unit, and sends the control information to the main control board.

7. A balancing management strategy based on the energy storage system according to any one of claims 1 to 6, characterized in that: It includes battery module energy consumption balancing management strategy, battery pack charge balancing management strategy and energy storage system charge and discharge balancing management strategy.

8. The balancing management strategy according to claim 7, characterized in that: The battery module energy consumption balancing management strategy includes: During the non-charging and discharging process, each slave control board obtains the voltage of each battery module in the corresponding battery pack, and determines the battery module voltage target value according to the voltage of each battery module; The voltage value of each battery module is compared with the target value. When the difference exceeds a first preset threshold, the slave control board controls the switch component to connect, the energy consumption resistor is connected in parallel with the battery module, and the energy consumption resistor discharges to consume the power of the battery module.

9. The balancing management strategy according to claim 7, characterized in that: The battery pack charge balancing management strategy includes: During non-charging or non-discharging or charging processes, each of the main control boards obtains information about each battery module in the corresponding battery pack, including the state of charge of the battery modules, and determines the state of charge of the highest battery module as the target state of charge of the battery module; The difference between the state of charge of each battery module in the battery pack and the target value is determined in sequence. When the difference exceeds a second preset threshold, the main control board generates charging control information for the corresponding module, and the main control board uses a polling mode to charge the corresponding battery module one by one; The slave control board receives the charging control information sent from the master control board, and controls the charging module to charge the corresponding battery module.

10. The balancing management strategy according to claim 7, characterized in that: The energy storage system charge and discharge balance management strategy includes: During the charging and discharging process, the system control board receives the state of charge of each battery pack and determines the target value of the state of charge of the battery pack; sequentially determining a difference between the state of charge of each battery pack and a target state of charge value of the battery pack, and generating a charge and discharge current control signal when the difference exceeds a third preset threshold; The system control board sends the charge and discharge current control signal to the bidirectional DC converter through the battery management and control unit; the bidirectional DC converter independently adjusts the electric energy input or output power of the corresponding DC conversion channel.

Images