A battery string DC converging and string balancing control device for an energy storage system

Abstract

The present invention belongs to the technical field of battery energy storage application, and specifically relates to a battery string DC convergence and string balancing control device for an energy storage system. The battery monitoring and management module in the battery string DC convergence and string balancing control device collects the voltage, current, power and other electrical energy parameters and temperature parameters of each battery string and all battery cells in real time, and performs electrical energy balancing control with the battery string as the control unit according to the degree of inconsistency between the corresponding battery cells and the battery string and the operation assurance parameters preset by the comparison system. By controlling the on-off of the control and protection circuits connected and set for each battery string and during the charging and discharging process of the bidirectional energy storage inverter, the electrical energy balancing of the corresponding battery string is completed, thereby reducing the battery cell balancing loop and risk, saving investment and improving the safety of the energy storage system, and having a positive effect and beneficial contribution to the application and promotion of the battery energy storage system.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical battery energy storage application, and in particular relates to a battery string DC convergence and string balancing control device for an energy storage system. Background Art

[0002] Battery energy storage system is an important part of electric vehicle new energy power, smart grid and energy Internet. In particular, electrochemical battery energy storage system is a battery string composed of multiple battery cells connected to enter the inverter equipment for charging and discharging, and completes power regulation and charging and discharging in a controlled manner. Due to the differences in the physical and chemical properties of each battery cell, coupled with the differences in environmental dimensions during installation and operation, the batteries in the battery string produce inconsistencies in voltage and power, which affects the overall efficiency and utilization of the battery string and also brings safety hazards.

[0003] In this regard, real-time monitoring of battery operation, charge and discharge current control, voltage and power of each battery cell in a battery string and other energy consistency balancing control are the key to the safe, healthy and efficient operation of the energy storage system. Most of the existing battery management systems BMS monitor each battery cell and battery packs with multiple battery cells in parallel in real time and perform static or dynamic energy balancing in real time. Each battery cell and battery pack with multiple battery cells in parallel is equipped with a balancing circuit and loop, which not only greatly increases the investment cost, but also the huge number of charge and discharge current circuit loops pose unexpected risks to the energy storage system. Summary of the invention

[0004] In order to solve the defects of the existing technology in the battery management of the energy storage system and save investment on the basis of providing safety, the present invention proposes a battery string DC bus and string balancing control device of the energy storage system, including: a battery string DC bus and string balancing control device, a battery monitoring management module, a host computer communication line, a bidirectional energy storage inverter communication line, a bidirectional energy storage inverter, a battery string DC bus bus, a bidirectional energy storage inverter AC power line, a battery monitoring management module monitoring bus, a power grid, an energy storage system host computer, a first battery string, a first battery string battery parameter acquisition module, a first battery string battery parameter acquisition module, a second ... 1 battery string battery parameter collection harness, 1 battery string DC power line, 1 battery string DC power line on-off switch and protection circuit, 2 battery string, 2 battery string battery parameter collection module, 2 battery string battery parameter collection harness, 2 battery string DC power line, 2 battery string DC power line on-off switch and protection circuit, N battery string, N battery string battery parameter collection module, N battery string battery parameter collection harness, N battery string DC power line, N battery string DC power line on-off switch and protection circuit, wherein:

[0005] The first battery string DC power line on-off switch and protection circuit, the second battery string DC power line on-off switch and protection circuit, the N battery string DC power line on-off switch and protection circuit, the battery string DC busbar and the battery monitoring management module are installed in one cabinet, forming a battery string DC busbar and string balancing control device for performing battery string power balancing and safety protection on-off control;

[0006] The first battery string connected to the battery parameter collection module of the first battery string through the battery parameter collection harness of the first battery string is connected to the first battery string DC power line on-off switch and protection circuit via the first battery string DC power line, and the first battery string DC power line on-off switch and protection circuit are connected to the power grid in sequence via the battery string DC busbar, the bidirectional energy storage inverter, and the bidirectional energy storage inverter AC power line, forming a power path for charging and discharging the first battery string;

[0007] The second battery string connected to the battery parameter collection module of the second battery string through the battery parameter collection harness of the second battery string is connected to the DC power line on-off switch and protection circuit of the second battery string through the DC power line of the second battery string, and the DC power line on-off switch and protection circuit of the second battery string are connected to the power grid in sequence through the DC busbar of the battery string, the bidirectional energy storage inverter, and the AC power line of the bidirectional energy storage inverter, thereby forming a power path for charging and discharging the second battery string;

[0008] The Nth battery string connected to the battery parameter collection module of the Nth battery string through the battery parameter collection harness of the Nth battery string is connected to the DC power line on-off switch and protection circuit of the Nth battery string through the DC power line of the Nth battery string, and the DC power line on-off switch and protection circuit of the Nth battery string are connected to the power grid in sequence through the DC busbar of the battery string, the bidirectional energy storage inverter, and the AC power line of the bidirectional energy storage inverter, forming a power path for charging and discharging the Nth battery string;

[0009] The first battery string battery parameter acquisition harness is connected to each battery cell in the first battery string through the first battery string battery parameter acquisition module, forming the first battery string single cell battery parameter real-time monitoring subsystem and connected to the battery monitoring management module of the battery string DC bus and the battery monitoring management module of the string balancing control device through the battery monitoring management module monitoring bus;

[0010] The second battery string battery parameter acquisition harness is connected to each battery cell in the second battery string through the second battery string battery parameter acquisition module, forming a second battery string single cell battery parameter real-time monitoring subsystem and connected to the battery monitoring management module of the battery string DC bus and the battery monitoring management module of the string balancing control device through the battery monitoring management module monitoring bus;

[0011] The battery parameter acquisition harness of the Nth battery string is connected to each battery cell in the Nth battery string through the battery parameter acquisition module of the Nth battery string, forming a real-time monitoring subsystem for battery parameters of the Nth battery string, and is connected to the battery monitoring management module of the battery string DC bus and the battery monitoring management module of the string balancing control device through the monitoring bus of the battery monitoring management module;

[0012] The battery monitoring and management module is connected to the first battery string battery parameter acquisition module, the second battery string battery parameter acquisition module, the Nth battery string battery parameter acquisition module, and the first battery string DC power line on-off switch and protection circuit, the second battery string DC power line on-off switch and protection circuit, and the Nth battery string DC power line on-off switch and protection circuit through the battery monitoring and management module monitoring bus, forming a communication link for real-time monitoring of each battery string and all battery cells of the overall energy storage system and energy balancing management and control of the battery string;

[0013] The battery monitoring and management module is connected to the bidirectional energy storage inverter through the bidirectional energy storage inverter communication line, forming a control link for the battery monitoring and management module to manage and control the bidirectional energy storage inverter to perform power regulation of battery charging and discharging and battery string power balancing;

[0014] The host computer of the energy storage system is connected to the battery monitoring and management module through the host computer communication line, forming a control communication link for the host computer of the energy storage system to monitor and control the charging and discharging of the battery string in real time through the battery monitoring and management module;

[0015] The host computer of the energy storage system is connected to the bidirectional energy storage inverter via the host computer communication line, forming a control link for the host computer of the energy storage system to regulate the charging and discharging of the bidirectional energy storage inverter;

[0016] An operation control method of a battery string DC convergence and string balancing control device of an energy storage system is as follows:

[0017] ① During the power-on and operation of a battery string DC bus and string balancing control device of an energy storage system, the battery monitoring management module in the battery string DC bus and string balancing control device and the host computer of the energy storage system perform real-time monitoring of each battery string and all battery cells in parallel;

[0018] ② In case of abnormality, alarm and stop operation;

[0019] ③ Under normal circumstances, the battery monitoring management module of the battery string DC bus and string balancing control device monitors the voltage, current, temperature and calculated stored electricity of each battery string and all battery cells of the energy storage system in real time and compares the consistency of the parameters, and compares and judges with the preset operation assurance parameters of the system. When it is detected that the preset operation assurance parameter requirements of the system are not met, an alarm message is sent to the bidirectional energy storage inverter and the host computer of the energy storage system, and at the same time, the on-off switch of the corresponding battery string DC power line and the protection circuit in the battery string DC bus and string balancing control device are controlled according to the conditions set by the system;

[0020] ④ When the preset operation guarantee parameters of the system are met, the host computer of the energy storage system monitors the real-time parameters of each battery string and all battery cells of the energy storage system according to the power demand of the power grid and the DC convergence of the battery strings and the battery monitoring management module in the string balancing control device, and controls the charging and discharging power of the bidirectional energy storage inverter according to the preset control strategy of the system; ⑤ is performed during charging, and ⑥ is performed during discharging;

[0021] ⑤Continue to operate. The host computer of the energy storage system monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module in the battery string DC convergence and string balancing control device, and performs battery string power balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system. That is, during the charging process, the battery strings whose electric energy is higher than the average value of each battery string and whose consistency deviation value is higher than the operation assurance requirement control the corresponding battery string DC power line on-off switch and protection circuit to be disconnected. When the electric energy of the corresponding battery string is lower than the average value of each battery string and the consistency deviation value is within the operation assurance requirement range, the corresponding battery string DC power line on-off switch and protection circuit are controlled to be closed, and then go to ①;

[0022] ⑥Continue to operate. The host computer of the energy storage system monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module in the battery string DC convergence and string balancing control device, and performs battery string power balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system. That is, during the discharge process, the battery strings whose power is lower than the average value of the battery strings and whose consistency deviation value is lower than the operation assurance requirement control the corresponding battery string DC power line on-off switch and protection circuit to be disconnected. When the power of the corresponding battery string is higher than the average value of the battery string and the consistency deviation value is within the operation assurance requirement range, control the corresponding battery string DC power line on-off switch and protection circuit to be closed, and go to ①;

[0023] After the energy storage system based on battery string control is started normally, the upper computer of the energy storage system controls and circulates steps ① to ⑥, disconnecting the power path of the corresponding battery strings whose electric energy during charging is higher than the average value of each battery string during discharging and whose consistency deviation value is greater than the system preset operation assurance parameter requirement value, and connecting the corresponding power path when the equilibrium condition parameter value is met, so as to control the safe and efficient operation of the overall energy storage system.

[0024] The battery monitoring and management module of the energy storage system battery string DC convergence and string balancing control device is characterized by being mainly composed of an embedded controller, a program and data storage circuit, a clock circuit, a power supply circuit, a communication management and interface circuit, an I / O drive control and interface and isolation protection circuit, an analog-to-digital conversion circuit, a circuit control bus, and a manual control circuit module, wherein:

[0025] The embedded controller is connected to the program and data storage circuit, clock circuit, power supply circuit, communication management and interface circuit, I / O drive control and interface and isolation protection circuit, analog-to-digital conversion circuit, and manual control circuit module through the circuit control bus, forming a monitoring information link and signal acquisition and processing circuit module for real-time signal acquisition and processing of battery string units and manual control.

[0026] The present invention provides a battery string DC bus and string balancing control device for an energy storage system. The battery monitoring and management module in the battery string DC bus and string balancing control device collects electric energy parameters and temperature parameters such as voltage, current, and power of each battery string and all battery cells in real time, and performs electric energy balancing control with the battery string as the control unit according to the degree of inconsistency between the corresponding battery cells and the battery string and the preset operation assurance parameters of the comparison system. By performing on-off control on the control and protection circuits connected and set for each battery string and controlling and completing the electric energy balancing of the corresponding battery string during the charging and discharging process of the bidirectional energy storage inverter, the loop and risk of battery cell balancing are greatly reduced, the safety of the energy storage system is greatly improved while saving investment, and the application and promotion of electrochemical battery energy storage systems are played a positive role and beneficial contribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic diagram of the composition and principle of a battery string DC bus and string balancing control device for an energy storage system.

[0028] Figure 2 This is a schematic diagram of the composition and principle of the battery monitoring and management module. DETAILED DESCRIPTION

[0029] As an implementation example, a battery string unit module and a monitoring and management system are described in conjunction with the accompanying drawings. However, the described embodiment is a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The technology and solutions of the present invention are not limited to the contents given in this embodiment example.

[0030] like Figure 1As shown, a battery string DC busbar and string balancing control device for an energy storage system comprises: a battery string DC busbar and string balancing control device (1), a battery monitoring and management module (2), a host computer communication line (3), a bidirectional energy storage inverter communication line (4), a bidirectional energy storage inverter (5), a battery string DC busbar (6), a bidirectional energy storage inverter AC power line (7), a battery monitoring and management module monitoring bus (8), a power grid (9), an energy storage system host computer (30), a first battery string (10), a first battery string battery parameter acquisition module (11), a first battery string battery parameter acquisition wiring harness (12), and a first battery string DC busbar (6). The invention relates to a first battery string DC power line (13), a first battery string DC power line on-off switch and a protection circuit (14), a second battery string (20), a second battery string battery parameter collection module (21), a second battery string battery parameter collection wiring harness (22), a second battery string DC power line (23), a second battery string DC power line on-off switch and a protection circuit (24), an Nth battery string (N0), an Nth battery string battery parameter collection module (N1), an Nth battery string battery parameter collection wiring harness (N2), an Nth battery string DC power line (N3), and an Nth battery string DC power line on-off switch and a protection circuit (N4), wherein:

[0031] The first battery string DC power line on-off switch and protection circuit (14), the second battery string DC power line on-off switch and protection circuit (24), the N battery string DC power line on-off switch and protection circuit (N4), the battery string DC busbar (6) and the battery monitoring management module (2) are installed in a cabinet to form a battery string DC busbar and string balancing control device (1) for performing battery string power balancing and safety protection on-off control;

[0032] The first battery string (10) connected to the first battery string battery parameter acquisition module (11) via the first battery string battery parameter acquisition harness (12) is connected to the first battery string DC power line on-off switch and protection circuit (14) via the first battery string DC power line (13), and the first battery string DC power line on-off switch and protection circuit (14) are connected to the power grid (9) in sequence via the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the first battery string (10);

[0033] The second battery string (20) connected to the second battery string battery parameter acquisition module (21) via the second battery string battery parameter acquisition harness (22) is connected to the second battery string DC power line on-off switch and protection circuit (24) via the second battery string DC power line (23), and the second battery string DC power line on-off switch and protection circuit (24) are connected to the power grid (9) in sequence via the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the second battery string (20);

[0034] The Nth battery string (NO) connected to the Nth battery string battery parameter acquisition module (N1) through the Nth battery string battery parameter acquisition harness (N2) is connected to the Nth battery string DC power line on-off switch and protection circuit (N4) through the Nth battery string DC power line (N3), and the Nth battery string DC power line on-off switch and protection circuit (N4) are connected to the power grid (9) in sequence through the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the Nth battery string (N0);

[0035] The first battery string battery parameter acquisition harness (12) is connected to each battery cell in the first battery string (10) through the first battery string battery parameter acquisition module (11), forming a first battery string (10) single cell battery parameter real-time monitoring subsystem and is connected to the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) through the battery monitoring management module monitoring bus (8);

[0036] The second battery string battery parameter acquisition harness (22) is connected to each battery cell in the second battery string (20) through the second battery string battery parameter acquisition module (21), forming a second battery string (20) single cell battery parameter real-time monitoring subsystem and is connected to the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) through the battery monitoring management module monitoring bus (8);

[0037] The Nth battery string battery parameter acquisition harness (N2) is connected to each battery cell in the Nth battery string (NO) through the Nth battery string battery parameter acquisition module (N1), forming a real-time monitoring subsystem for battery cell parameters of the Nth battery string (N0), and is connected to the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) through the battery monitoring management module monitoring bus (8);

[0038] The battery monitoring and management module (2) is respectively connected to the first battery string battery parameter acquisition module (11), the second battery string battery parameter acquisition module (21), the Nth battery string battery parameter acquisition module (N1), the first battery string DC power line on-off switch and protection circuit (14), the second battery string DC power line on-off switch and protection circuit (24), and the Nth battery string DC power line on-off switch and protection circuit (N4) through the battery monitoring and management module monitoring bus (8), forming a communication link for real-time monitoring of each battery string and all battery cells of the overall energy storage system and energy balancing management and control of the battery strings;

[0039] The battery monitoring management module (2) is connected to the bidirectional energy storage inverter (5) via the bidirectional energy storage inverter communication line (4), forming a control link in which the battery monitoring management module (2) manages and controls the bidirectional energy storage inverter (5) to perform power regulation of battery charging and discharging and battery string power balancing;

[0040] The energy storage system host computer (30) is connected to the battery monitoring and management module (2) via the host computer communication line (3), thereby forming a control communication link for the energy storage system host computer (30) to monitor and control the charging and discharging of the battery group string in real time via the battery monitoring and management module (2);

[0041] The energy storage system host computer (30) is connected to the bidirectional energy storage inverter (5) via the host computer communication line (3), forming a control link for the energy storage system host computer (30) to regulate the charging and discharging of the bidirectional energy storage inverter (5);

[0042] An operation control method of a battery string DC convergence and string balancing control device of an energy storage system is as follows:

[0043] ① During the power-on and operation of a battery string DC bus and string balancing control device of an energy storage system, a battery monitoring management module (2) in the battery string DC bus and string balancing control device (1) and an energy storage system host computer (30) perform real-time monitoring of each battery string and all battery cells in parallel;

[0044] ② In case of abnormality, alarm and stop operation;

[0045] ③ Under normal circumstances, the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) monitors the voltage, current, temperature of each battery string and all battery cells of the energy storage system in real time, calculates the stored electricity, and compares the consistency of the parameters, and compares and determines with the system preset operation assurance parameters. When it is detected that the system preset operation assurance parameter requirements are not met, an alarm message is sent to the bidirectional energy storage inverter (5) and the energy storage system host computer (30), and at the same time, the on-off switch of the corresponding battery string DC power line and the protection circuit in the battery string DC bus and string balancing control device (1) are controlled according to the conditions set by the system;

[0046] ④ When the preset operation guarantee parameters of the system are met, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system according to the power demand of the power grid (9) and the battery string DC convergence and string balancing control device (1), and controls the charging and discharging power of the bidirectional energy storage inverter (5) according to the preset control strategy of the system; ⑤ is performed during charging, and ⑥ is performed during discharging;

[0047] ⑤ Continue to run, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module (2) in the battery string DC convergence and string balancing control device (1), and performs battery string power balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system, that is, during the charging process, for the battery strings whose power is higher than the average value of the battery strings and whose consistency deviation value is higher than the operation assurance requirement, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be disconnected; when the power of the corresponding battery string is lower than the average value of the battery string and the consistency deviation value is within the operation assurance requirement range, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be closed, and then go to ①;

[0048] ⑥ Continue to run, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module (2) in the battery string DC convergence and string balancing control device (1), and performs battery string electric energy balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system, that is, during the discharge process, for the battery strings whose electric energy is lower than the average value of the battery strings and whose consistency deviation value is lower than the operation assurance requirement, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be disconnected; when the electric energy of the corresponding battery string is higher than the average value of the battery strings and the consistency deviation value is within the operation assurance requirement range, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be closed, and the process goes to ①;

[0049] After the energy storage system based on the control of battery strings is started normally, the upper computer (30) of the energy storage system controls and circulates the steps ① to ⑥, disconnecting the power path of the corresponding battery strings whose electric energy during charging is higher than the average value of each battery string and during discharging is lower than the average value of each battery string and whose consistency deviation value is greater than the system preset operation assurance parameter requirement value in real time, and connecting the corresponding power path when the equilibrium condition parameter value is met, thereby controlling the safe and efficient operation of the overall energy storage system.

[0050] As attached Figure 2 The battery monitoring and management module (2) of the energy storage system is characterized by being mainly composed of an embedded controller (201), a program and data storage circuit (202), a clock circuit (203), a power supply circuit (204), a communication management and interface circuit (205), an I / O drive control and interface and isolation protection circuit (206), an analog-to-digital conversion circuit (207), a circuit control bus (208), and a manual control circuit module (209), wherein:

[0051] The embedded controller (201) is respectively connected to a program and data storage circuit (202), a clock circuit (203), a power supply circuit (204), a communication management and interface circuit (205), an I / O drive control and interface and isolation protection circuit (206), an analog-to-digital conversion circuit (207), and a manual control circuit module (209) via a circuit control bus (208), thereby forming a monitoring information link and a signal acquisition and processing circuit module for real-time signal acquisition and processing of battery string units and manual control.

[0052] The present invention provides a battery string DC convergence and string balancing control device for an energy storage system. The battery monitoring management module (2) in the battery string DC convergence and string balancing control device (1) collects the voltage, current, power and other energy parameters and temperature parameters of each battery string and all battery cells in real time, and performs energy balancing control with the battery string as the control unit according to the inconsistency between the corresponding battery cells and the battery string and the operation assurance parameters preset by the comparison system. By controlling the on-off of the control and protection circuit connected and set for each battery string and controlling the energy balancing of the corresponding battery string during the charging and discharging process of the bidirectional energy storage inverter (5), the circuit and risk of battery cell balancing are greatly reduced, the safety of the energy storage system is greatly improved while saving investment, and the application and promotion of electrochemical battery energy storage systems are actively played and beneficially contributed.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery string DC convergence and string balancing control device for an energy storage system, comprising: A battery string DC busbar and string balancing control device (1), a battery monitoring and management module (2), a host computer communication line (3), a bidirectional energy storage inverter communication line (4), a bidirectional energy storage inverter (5), a battery string DC busbar (6), a bidirectional energy storage inverter AC power line (7), a battery monitoring and management module monitoring bus (8), a power grid (9), an energy storage system host computer (30), a first battery string (10), a first battery string battery parameter acquisition module (11), a first battery string battery parameter acquisition wiring harness (12), a first battery string DC power line (13), a first battery string A DC power line on-off switch and protection circuit (14), a second battery string (20), a second battery string battery parameter collection module (21), a second battery string battery parameter collection wiring harness (22), a second battery string DC power line (23), a second battery string DC power line on-off switch and protection circuit (24), an Nth battery string (N0), an Nth battery string battery parameter collection module (N1), an Nth battery string battery parameter collection wiring harness (N2), an Nth battery string DC power line (N3), an Nth battery string DC power line on-off switch and protection circuit (N4), wherein: The first battery string DC power line on-off switch and protection circuit (14), the second battery string DC power line on-off switch and protection circuit (24), the N battery string DC power line on-off switch and protection circuit (N4), the battery string DC busbar (6) and the battery monitoring management module (2) are installed in a cabinet to form a battery string DC busbar and string balancing control device (1) for performing battery string power balancing and safety protection on-off control; The first battery string (10) connected to the first battery string battery parameter acquisition module (11) via the first battery string battery parameter acquisition harness (12) is connected to the first battery string DC power line on-off switch and protection circuit (14) via the first battery string DC power line (13), and the first battery string DC power line on-off switch and protection circuit (14) are connected to the power grid (9) in sequence via the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the first battery string (10); The second battery string (20) connected to the second battery string battery parameter acquisition module (21) via the second battery string battery parameter acquisition harness (22) is connected to the second battery string DC power line on-off switch and protection circuit (24) via the second battery string DC power line (23), and the second battery string DC power line on-off switch and protection circuit (24) are connected to the power grid (9) in sequence via the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the second battery string (20); The Nth battery string (N0) connected to the Nth battery string battery parameter acquisition module (N1) through the Nth battery string battery parameter acquisition harness (N2) is connected to the Nth battery string DC power line on-off switch and protection circuit (N4) through the Nth battery string DC power line (N3), and the Nth battery string DC power line on-off switch and protection circuit (N4) are connected to the power grid (9) in sequence through the battery string DC busbar (6), the bidirectional energy storage inverter (5), and the bidirectional energy storage inverter AC power line (7), thereby forming a power path for charging and discharging the Nth battery string (N0); The first battery string battery parameter acquisition harness (12) is connected to each battery cell in the first battery string (10) through the first battery string battery parameter acquisition module (11), forming a first battery string (10) single cell battery parameter real-time monitoring subsystem and is connected to the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) through the battery monitoring management module monitoring bus (8); The second battery string battery parameter acquisition harness (22) is connected to each battery cell in the second battery string (20) through the second battery string battery parameter acquisition module (21), forming a second battery string (20) single cell battery parameter real-time monitoring subsystem and is connected to the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) through the battery monitoring management module monitoring bus (8); The Nth battery string battery parameter acquisition harness (N2) is connected to each battery cell in the Nth battery string (N0) through the Nth battery string battery parameter acquisition module (N1), forming a real-time monitoring subsystem for battery cell parameters of the Nth battery string (N0) and connected to a battery monitoring management module (2) of a battery string DC bus and a string balancing control device (1) through a battery monitoring management module monitoring bus (8); The battery monitoring and management module (2) is respectively connected to the first battery string battery parameter acquisition module (11), the second battery string battery parameter acquisition module (21), the Nth battery string battery parameter acquisition module (N1), the first battery string DC power line on-off switch and protection circuit (14), the second battery string DC power line on-off switch and protection circuit (24), and the Nth battery string DC power line on-off switch and protection circuit (N4) through the battery monitoring and management module monitoring bus (8), forming a communication link for real-time monitoring of each battery string and all battery cells of the overall energy storage system and energy balancing management and control of the battery strings; The battery monitoring management module (2) is connected to the bidirectional energy storage inverter (5) via the bidirectional energy storage inverter communication line (4), forming a control link in which the battery monitoring management module (2) manages and controls the bidirectional energy storage inverter (5) to perform power regulation of battery charging and discharging and battery string power balancing; The energy storage system host computer (30) is connected to the battery monitoring and management module (2) via the host computer communication line (3), thereby forming a control communication link for the energy storage system host computer (30) to monitor and control the charging and discharging of the battery group string in real time via the battery monitoring and management module (2); The energy storage system host computer (30) is connected to the bidirectional energy storage inverter (5) via the host computer communication line (3), forming a control link for the energy storage system host computer (30) to regulate the charging and discharging of the bidirectional energy storage inverter (5); An operation control method of a battery string DC convergence and string balancing control device of an energy storage system is as follows: ① During the power-on and operation of a battery string DC bus and string balancing control device of an energy storage system, a battery monitoring management module (2) in the battery string DC bus and string balancing control device (1) and an energy storage system host computer (30) perform real-time monitoring of each battery string and all battery cells in parallel; ② In case of abnormality, alarm and stop operation; ③ Under normal circumstances, the battery monitoring management module (2) of the battery string DC bus and string balancing control device (1) monitors the voltage, current, temperature of each battery string and all battery cells of the energy storage system in real time, calculates the stored electricity, and compares the consistency of the parameters, and compares and determines with the system preset operation assurance parameters. When it is detected that the system preset operation assurance parameter requirements are not met, an alarm message is sent to the bidirectional energy storage inverter (5) and the energy storage system host computer (30), and at the same time, the on-off switch of the corresponding battery string DC power line and the protection circuit in the battery string DC bus and string balancing control device (1) are controlled according to the conditions set by the system; ④ When the preset operation guarantee parameters of the system are met, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system according to the power demand of the power grid (9) and the battery string DC convergence and string balancing control device (1), and controls the charging and discharging power of the bidirectional energy storage inverter (5) according to the preset control strategy of the system; ⑤ is performed during charging, and ⑥ is performed during discharging; ⑤ Continue to run, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module (2) in the battery string DC convergence and string balancing control device (1), and performs battery string power balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system, that is, during the charging process, for the battery strings whose power is higher than the average value of the battery strings and whose consistency deviation value is higher than the operation assurance requirement, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be disconnected; when the power of the corresponding battery string is lower than the average value of the battery string and the consistency deviation value is within the operation assurance requirement range, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be closed, and then go to ①; ⑥ Continue to run, the energy storage system host computer (30) monitors the real-time parameters of each battery string and all battery cells of the energy storage system through the battery monitoring management module (2) in the battery string DC convergence and string balancing control device (1), and performs battery string electric energy balancing control according to the inconsistency between the corresponding battery strings and the operation assurance parameters preset by the comparison system, that is, during the discharge process, for the battery strings whose electric energy is lower than the average value of the battery strings and whose consistency deviation value is lower than the operation assurance requirement, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be disconnected; when the electric energy of the corresponding battery string is higher than the average value of the battery strings and the consistency deviation value is within the operation assurance requirement range, the DC power line on / off switch and protection circuit of the corresponding battery string are controlled to be closed, and the process goes to ①; After the energy storage system based on the control of battery strings is started normally, the upper computer (30) of the energy storage system controls and circulates the steps ① to ⑥, disconnecting the power path of the corresponding battery strings whose electric energy during charging is higher than the average value of each battery string and during discharging is lower than the average value of each battery string and whose consistency deviation value is greater than the system preset operation assurance parameter requirement value in real time, and connecting the corresponding power path when the equilibrium condition parameter value is met, thereby controlling the safe and efficient operation of the overall energy storage system.

2. According to the device for controlling the direct current convergence and balancing of battery strings of an energy storage system as claimed in claim 1, the battery monitoring and management module (2) is characterized in that it is mainly composed of an embedded controller (201), a program and data storage circuit (202), a clock circuit (203), a power supply circuit (204), a communication management and interface circuit (205), an I / O drive control and interface and isolation protection circuit (206), an analog-to-digital conversion circuit (207), a circuit control bus (208), and a manual control circuit module (209), wherein: The embedded controller (201) is respectively connected to a program and data storage circuit (202), a clock circuit (203), a power supply circuit (204), a communication management and interface circuit (205), an I / O drive control and interface and isolation protection circuit (206), an analog-to-digital conversion circuit (207), and a manual control circuit module (209) via a circuit control bus (208), thereby forming a monitoring information link and a signal acquisition and processing circuit module for real-time signal acquisition and processing of battery string units and manual control.

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