High-reuse battery pack equalization system, method and equipment

Abstract

The invention discloses a high-reuse battery pack balancing system, method and equipment, and relates to the field of energy storage of new energy power systems. The system is characterized in that each energy storage unit is connected with a power grid and a digital energy exchange unit; the AC end of the energy storage converter is connected with the power grid, the anode of the DC end is connected with the anode of the battery cluster, and the cathode of the battery cluster is connected with the anode of the relay; the positive electrode and the negative electrode of each battery pack in each battery cluster are connected with the digital energy exchange unit; the cathode of the relay is connected with the cathode of the energy storage converter, and the normally open contact of the relay is connected with the digital energy exchange unit; and the digital energy exchange unit is connected with the control end of the energy storage converter and is used for performing data acquisition, charging and discharging, charging and circuit protection actions in a time-sharing manner according to the state of the battery cluster. According to the invention, the reliability and reusability during battery equalization are improved, the utilization rate of power elements and the battery equalization cost are reduced, and the battery equalization energy consumption is reduced by time-sharing data acquisition and control.

Description

Technical Field

[0001] This application relates to the field of energy storage in new energy power systems, and particularly to a high-reusability battery pack balancing system, method, and device. Background Art

[0002] The global energy transition triggered by new energy has put forward an urgent demand for low-cost and sustainable energy storage solutions. For example, the explosive growth of the new energy vehicle industry has brought a large-scale wave of retired power batteries. The remaining capacity at the end of the battery life (usually 70%-80% of the initial capacity) can still meet the energy storage needs of low-rate and non-mobile scenarios. Directly reusing the complete battery pack can avoid the high costs and safety risks of disassembly and recombination, while alleviating the pressure on the mining of scarce resources such as lithium and cobalt. Its core utilization value lies in economy (the cost of retired batteries is only 30%-50% of that of new batteries, significantly reducing the initial investment of the energy storage system), environmental protection (reducing battery waste pollution and resource waste), and social benefits (extending the value of the industrial chain and alleviating the pressure on grid expansion). Retired standby battery packs need to be balanced when participating in energy storage.

[0003] In some cases, the fixed series-parallel scheme of the battery pack depends on strict battery sorting, and the battery pack balancing functional circuit has problems such as high cost, high energy consumption, and high failure rate, making it difficult to be widely promoted and deployed on a large scale. Summary of the Invention

[0004] The purpose of this application is to provide a high-reusability battery pack balancing system, method, and device, which can improve the reliability and reusability during battery balancing, reduce the usage rate of power components and the battery balancing cost, and reduce the energy consumption of battery balancing.

[0005] To achieve the above object, this application provides the following solutions:

[0006] In a first aspect, the present application provides a highly reusable battery pack equalization system. The highly reusable battery pack equalization system includes: a digital energy exchange unit and a plurality of energy storage units; one end of each energy storage unit is connected to the power grid, and the other end is connected to the digital energy exchange unit; each energy storage unit includes: an energy storage inverter, a battery cluster, and a relay; the battery cluster includes: a plurality of battery packs connected in series in sequence; the AC terminal of the energy storage inverter is connected to the power grid; the positive electrode of the battery cluster is connected to the positive electrode of the DC terminal of the energy storage inverter, and the negative electrode of the battery cluster is connected to the positive electrode of the relay; the positive and negative electrodes of each battery pack within each battery cluster are both connected to the digital energy exchange unit; the negative electrode of the relay is connected to the negative electrode of the energy storage inverter, and the normally open contact of the relay is connected to the digital energy exchange unit; the digital energy exchange unit is connected to the control terminal of the energy storage inverter; the digital energy exchange unit is configured to, when the battery cluster enters the off-line measurement state, disconnect the relay, and obtain the maximum open-circuit voltage, the minimum open-circuit voltage, and the temperature of each battery pack; when the battery cluster enters the on-line measurement state, close the relay, and obtain the working voltage and the temperature of each battery pack; when the battery cluster enters the on-line charge and discharge state, close the relay, and control the energy storage inverter to charge and discharge the battery cluster; when the battery cluster enters the off-line charge compensation state, disconnect the relay, and perform equalization charge compensation on the target battery pack; the target battery pack is the battery pack whose open-circuit voltage difference ratio is greater than a preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage; when a voltage abnormality or a temperature abnormality occurs in the battery pack, disconnect the corresponding relay.

[0007] In a second aspect, the present application provides a highly reusable battery pack equalization method. The highly reusable battery pack equalization method is applied to the highly reusable battery pack equalization system described above. The highly reusable battery pack equalization method includes: when the battery cluster enters the off-line measurement state, disconnect the relay through the digital energy exchange unit, and obtain the maximum open-circuit voltage, the minimum open-circuit voltage, and the temperature of each battery pack; when the battery cluster enters the on-line measurement state, close the relay through the digital energy exchange unit, and obtain the working voltage and the temperature of each battery pack; when the battery cluster enters the on-line charge and discharge state, close the relay through the digital energy exchange unit, and control the energy storage inverter to charge and discharge the battery cluster; when the battery cluster enters the off-line charge compensation state, disconnect the relay through the digital energy exchange unit, and perform equalization charge compensation on the target battery pack; the target battery pack is the battery pack whose open-circuit voltage difference ratio is greater than a preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage; when a voltage abnormality or a temperature abnormality occurs in the battery pack, disconnect the corresponding relay through the digital energy exchange unit.

[0008] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the high-reuse battery pack balancing method described above.

[0009] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0010] This application uses relays and digital energy exchange units to perform data collection, charging and discharging, power replenishment, and circuit protection actions on multiple battery packs in multiple battery clusters according to different modes of the battery cluster. It can use a digital energy exchange unit to complete the individual control of multiple battery packs, improve the reusability of battery balancing, and reduce the sorting requirements of battery packs. At the same time, the one-to-many control method simplifies the original battery balancing circuit, replaces a large number of DC / DC circuit components, and thus improves the reliability of battery balancing. At the same time, it reduces the utilization rate of power components in the battery balancing circuit, thereby reducing the cost of battery balancing. Data collection and control in different modes at different times reduce battery balancing energy consumption, and realize large-scale promotion and deployment of battery packs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0012] Figure 1 A schematic diagram of a high-reuse battery pack balancing system provided in an embodiment of the present application Figure 1 .

[0013] Figure 2 A schematic diagram of a high-reuse battery pack balancing system provided in an embodiment of the present application Figure 2 .

[0014] Figure 3 A schematic diagram of the working state transition of a battery cluster provided in an embodiment of the present application.

[0015] Figure 4 A flowchart of a high-reuse battery pack balancing method provided in an embodiment of the present application.

[0016] Figure 5 A flowchart for recycling retired / backup battery packs provided in an embodiment of the present application.

[0017] Figure 6Schematic structural diagram of a computer device provided by an embodiment of the present application.

[0018] Reference numerals: Digital energy exchange unit - 1; Interface module - 11; Measurement module - 12; Equalization module - 13; Protection module - 14; Digital energy management module - 15; Receiving module - 16; Battery replenishment robot - 17; Wireless communication module - 18; Energy storage unit - 2; Energy storage converter - 21; Battery cluster - 22; Battery pack - 221; Relay - 23. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0020] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0021] First, the most common scenarios for retired / spare battery packs include: user-side distributed energy storage (such as peak-valley electricity price arbitrage in factories, industrial parks, and commercial complexes), grid-side frequency modulation and peak shaving (smoothing the fluctuations of new energy power generation), renewable energy supporting energy storage (storing surplus electricity in photovoltaic / wind farms), and off-grid power supply for microgrids in remote areas. Its core utilization value is reflected in economy (the cost of retired batteries is only 30%-50% of that of new batteries, significantly reducing the initial investment of the energy storage system), environmental protection (reducing battery waste pollution and resource waste), and social benefits (extending the industrial chain value and alleviating the pressure of grid expansion). Typical cases such as "photovoltaic-energy storage-charging" integrated charging stations, household energy storage systems, and grid-level energy storage projects all achieve the safe operation of retired battery packs or backup battery packs under low-stress conditions through BMS (battery management system) upgrade, real-time monitoring of the state of health (SOH), and cluster-level equalization control. The cost per kilowatt-hour of the entire life cycle can be reduced by more than 40%, becoming an important pillar of the new energy industry closed-loop.

[0022] Secondly, the key issues to be addressed for retired backup battery packs to participate in energy storage include battery consistency management: due to long-term use, the differences in monomer capacity, internal resistance, and aging degree are significant, and direct reuse is likely to cause system imbalance; accurate assessment and grading of the state of health (SOH): relying on high-precision algorithms and detection technologies to avoid capacity overstatement or safety hazards; prevention and control of thermal runaway risks: the thermal stability of retired batteries decreases, and thermal management and monitoring need to be strengthened; life prediction and optimization of charge and discharge strategies: a dynamic model needs to be established to adapt to low-stress conditions and extend the cycle life; system integration compatibility: the protocols of the original vehicle BMS and the energy storage system do not match, and software and hardware transformation is required; lack of regulations and standards: there is no unified specification for echelon utilization certification, safety testing, and liability definition; economic balance: the sorting and recombination costs and the remaining value need to be matched to avoid excessive investment offsetting the low-cost advantage of retired batteries; and environmental protection recycling closed-loop: ensuring harmless treatment after secondary retirement to avoid final pollution. Among them, battery consistency management is the most critical core issue. There are various solutions in the industry. The current fixed series-parallel battery pack solution relies on strict battery sorting. However, as the battery packs are used for a long time, the imbalance between battery packs will gradually increase, and regular disassembly and charging are required, resulting in high long-term operation and maintenance costs. The battery pack string management solution generally uses a DC / DC circuit for battery pack balancing management. Since the voltage level of vehicle battery packs is relatively high, usually above 300V and the rated energy is above 60kWh, the corresponding DC / DC circuit cost is very high, making it difficult to deploy and promote on a large scale. Active balancing methods such as transformer voltage division have high costs and poor reliability. The solution based on dynamic reconfigurable battery network technology is also difficult to achieve a low-cost solution because the management object is a battery pack with a high voltage and high energy level.

[0023] Example 1, as Figure 1 and Figure 3 shown, this embodiment provides a high-reuse battery pack balancing system. The reuse battery pack balancing system includes: a digital energy exchange unit 1 and multiple energy storage units 2.

[0024] One end of each energy storage unit 2 is connected to the power grid, and the other end is connected to the digital energy exchange unit 1.

[0025] Each energy storage unit 2 includes: a power conversion system (PCS) 21, a battery cluster 22, and a relay 23; the battery cluster 22 includes: a plurality of battery packs 221 connected in series in sequence.

[0026] Further, the voltage range of the DC side of the power conversion system 21 is 600V - 1500V.

[0027] Further, the relay 23 is a high-voltage DC relay 23.

[0028] Further, the battery pack 221 is a retired battery pack 221 or a backup battery pack 221.

[0029] Optionally, measurement points are provided at the positive and negative electrodes of each battery pack 221 for voltage and temperature measurement and for equalizing and charging.

[0030] The AC side of the energy storage converter 21 is connected to the power grid.

[0031] The positive electrode of the battery cluster 22 is connected to the positive electrode of the DC side of the energy storage converter 21, and the negative electrode of the battery cluster 22 is connected to the positive electrode of the relay 23; the positive and negative electrodes of each battery pack 221 within each battery cluster 22 are both connected to the digital energy exchange unit 1.

[0032] The negative electrode of the relay 23 is connected to the negative electrode of the energy storage converter 21, and the normally open contact of the relay 23 is connected to the digital energy exchange unit 1.

[0033] In actual application, the relay 23 can be controlled by the digital energy exchange unit 1 to be disconnected and closed as needed. When disconnected, the open-circuit voltage of the battery pack 221 can be measured and equalizing and charging can be performed.

[0034] The digital energy exchange unit 1 is connected to the control terminal of the energy storage converter 21; the digital energy exchange unit 1 is used to disconnect the relay 23 when the battery cluster 22 enters the offline measurement state to obtain the maximum open-circuit voltage, minimum open-circuit voltage, and temperature of each battery pack 221; when the battery cluster 22 enters the online measurement state, close the relay 23 to obtain the working voltage and temperature of each battery pack 221; when the battery cluster 22 enters the online charge and discharge state, close the relay 23 to control the energy storage converter 21 to charge and discharge the battery cluster 22; when the battery cluster 22 enters the offline charging state, disconnect the relay 23 to perform equalizing and charging on the target battery pack 221; when a voltage anomaly or temperature anomaly occurs in the battery pack 221, disconnect the corresponding relay 23 (to avoid thermal runaway of the battery pack 221); the target battery pack 221 is a battery pack 221 with an open-circuit voltage difference ratio greater than a preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage.

[0035] Further, the preset value is 1%.

[0036] Optionally, the battery cluster 22 is a series battery cluster 22.

[0037] Optionally, each battery cluster 22 includes three battery packs 221.

[0038] Optionally, the battery pack 221 is a vehicle-use battery pack 221 with 360V and 68kWh.

[0039] Optionally, a single energy storage converter 21 manages only one battery cluster 22, avoiding the circulating current problem existing in multiple battery clusters 22.

[0040] Optionally, voltage anomalies include at least any one of overvoltage, undervoltage, and overcurrent.

[0041] Optionally, temperature anomalies include at least any one of overtemperature and undertemperature.

[0042] As an optional implementation method 1, when no BMS (Battery Monitoring and Management System) is provided in each battery pack 221, the digital energy exchange unit 1 includes: an interface module 11, a measurement module 12, a balancing module 13, a protection module 14, and a digital energy management module 15.

[0043] The interface module 11 is respectively connected to the control ends of all energy storage converters 21.

[0044] In the actual application process, the interface module 11 is responsible for the communication and command interaction with the energy storage converter 21.

[0045] The measurement module 12 is respectively connected to the positive and negative electrodes of all battery packs 221.

[0046] In the actual application process, the measurement module 12 is an optional module. In the scenario where there is no BMS module supporting the battery pack 221, the working voltage value and temperature value of each battery pack 221 port can be polled and collected through the time-sharing measurement module 12. Since the cell-level measurement data cannot be obtained, the cell faults cannot be accurately detected, and the time-sharing measurement method is adopted to reduce costs.

[0047] The balancing module 13 is respectively connected to the positive and negative electrodes of all battery packs 221.

[0048] In the actual application process, when the battery cluster 22 is in the offline state, the balancing module 13 receives the balancing instruction sent by the digital energy management module 15 and performs the charging operation on the target battery pack 221.

[0049] The protection module 14 is respectively connected to the normally open contacts of all relays 23.

[0050] In the actual application process, after receiving the instruction from the digital energy management module 15 to open and close the relay 23 switch, the protection module 14 performs the corresponding operation.

[0051] The digital energy management module 15 is respectively connected to the interface module 11, the measurement module 12, the equalization module 13 and the protection module 14; when the battery cluster 22 enters the off-line measurement state, the digital energy management module 15 is used to control the protection module 14 to disconnect the relay 23 and control the measurement module 12 to collect the maximum open-circuit voltage, the minimum open-circuit voltage and the temperature of each battery pack 221; when the battery cluster 22 enters the on-line measurement state, the digital energy management module 15 is used to control the protection module 14 to close the relay 23 and control the measurement module 12 to collect the working voltage and the temperature of each battery pack 221; when the battery cluster 22 enters the on-line charge and discharge state, the digital energy management module 15 is used to control the protection module 14 to close the relay 23 and control the energy storage converter 21 to charge and discharge the battery cluster 22; when the battery cluster 22 enters the off-line charging state, the digital energy management module 15 is used to control the protection module 14 to disconnect the relay 23 and control the equalization module 13 to perform equalization charging on the target battery pack 221; when the voltage or temperature of the battery pack 221 is abnormal, the digital energy management module 15 is used to control the protection module 14 to disconnect the corresponding relay 23.

[0052] In the actual application process, the digital energy management module 15 controls the working state of the battery cluster 22 according to the measurement information of the battery pack 221 and the charge and discharge instructions issued by the superior management system, including the off-line measurement state, the on-line measurement state, the on-line charge and discharge state, and the off-line charging state. Considering that the battery cluster 22 composed of retired or spare battery packs 221 is often used in application scenarios such as peak shaving and valley filling, the system can be in the off-line measurement and off-line charging states for a long time. During the idle time after the charge and discharge are completed, the digital energy management module 15 in the digital energy exchange unit 1 issues a disconnection operation to the relay 23 of all the battery clusters 22 it manages after reaching the preset time (2 hours), and the battery cluster 22 enters the off-line measurement state. After standing for 2 hours (or longer, determined according to the charge and discharge time constant of the battery cluster 22), the digital energy exchange unit 1 polls and collects the voltage measurement values of each battery pack 221. At this time, the voltage measurement values of each battery pack 221 are the open-circuit voltages of the battery packs 221. By analyzing the open-circuit voltage values of each battery pack 221 in the same cluster, if the difference ratio between the maximum open-circuit voltage value and the minimum open-circuit voltage value in the battery pack 221 is greater than 1%, the charging operation needs to be started. Taking the rated voltage of the battery pack 221 as 360V as an example, when the voltage difference is greater than 3.6V, the charging operation should be started, and the highest open-circuit voltage value is used as the charging target value. All battery packs 221 with a voltage difference greater than 3.6V need to be charged. The equalization module 13 of the digital energy exchange unit 1 uses a closed-loop control algorithm to charge the battery pack 221 in the way of constant current charging with a small current, and supports over-voltage, over-current, over-temperature, short-circuit and reverse connection protection designs to prevent the battery from overcharging or being damaged.

[0053] Further, when a BMS is provided in each battery pack 221, the digital energy exchange unit 1 includes: an interface module 11, a receiving module 16, a balancing module 13, a protection module 14, and a digital energy management module 15.

[0054] The interface module 11 is respectively connected to the control ends of all energy storage converters 21.

[0055] The receiving module 16 is respectively connected to the positive and negative electrodes of all battery packs 221.

[0056] The receiving module 16 is configured to obtain the cell-level voltage and temperature values of the BMS, analyze the SOX indicators of the battery pack 221 and the cells, as well as the OCV (Open Circuit Voltage) value based on the measurement data, and provide prediction and early warning information (voltage anomaly or temperature anomaly) for the digital energy management module 15 to analyze and make decisions and issue corresponding operation instructions.

[0057] The balancing module 13 is respectively connected to the positive and negative electrodes of all battery packs 221.

[0058] The protection module 14 is respectively connected to the normally open contacts of all relays 23.

[0059] The digital energy management module 15 is respectively connected to the interface module 11, the receiving module 16, the balancing module 13, and the protection module 14; when the battery cluster 22 enters the off-line measurement state, the digital energy management module 15 controls the protection module 14 to disconnect the relay 23 and controls the receiving module 16 to receive the maximum open circuit voltage, the minimum open circuit voltage, and the temperature collected by the BMS of each battery pack 221; when the battery cluster 22 enters the on-line measurement state, the digital energy management module 15 controls the protection module 14 to close the relay 23 and controls the receiving module 16 to receive the working voltage and temperature collected by the BMS of each battery pack 221; when the battery cluster 22 enters the on-line charge and discharge state, the digital energy management module 15 controls the protection module 14 to close the relay 23 and controls the energy storage converter 21 to charge and discharge the battery cluster 22; when the battery cluster 22 enters the off-line charge replenishment state, the digital energy management module 15 controls the protection module 14 to disconnect the relay 23 and controls the balancing module 13 to perform balancing charge replenishment on the target battery pack 221; when a voltage anomaly or temperature anomaly occurs in the battery pack 221, the digital energy management module 15 controls the protection module 14 to disconnect the corresponding relay 23.

[0060] As an optional second implementation manner, as Figure 2 shown, the digital energy exchange unit 1 includes: an interface module 11, a measurement module 12, a balancing module 13, a protection module 14, a digital energy management module 15, a charge replenishment robot 17, and a wireless communication module 18.

[0061] The interface module 11 is respectively connected to the control ends of all energy storage converters 21.

[0062] The measurement module 12 is respectively connected to the positive and negative electrodes of all battery packs 221.

[0063] The charging robot 17 is respectively connected to the positive and negative electrodes of all battery packs 221, and the charging robot is connected to the wireless communication module 18 through a wireless network.

[0064] The protection module 14 is respectively connected to the normally open contacts of all relays 23.

[0065] The digital energy management module 15 is respectively connected to the interface module 11, the measurement module 12, the charging robot 17, the protection module 14, and the wireless communication module 18; the digital energy management module 15 is used to control the protection module 14 to disconnect the relay 23 when the battery cluster 22 enters the off-line measurement state, and control the measurement module 12 to collect the maximum open-circuit voltage, minimum open-circuit voltage, and temperature of each battery pack 221; when the battery cluster 22 enters the on-line measurement state, control the protection module 14 to close the relay 23, and control the measurement module 12 to collect the working voltage and temperature of each battery pack 221; when the battery cluster 22 enters the on-line charge and discharge state, control the protection module 14 to close the relay 23, and control the energy storage converter 21 to charge and discharge the battery cluster 22; when the battery cluster 22 enters the off-line charging state, control the protection module 14 to disconnect the relay 23, and control the charging robot 17 to perform balanced charging on the target battery pack 221 through the wireless communication module 18; when the voltage or temperature of the battery pack 221 is abnormal, control the protection module 14 to disconnect the corresponding relay 23.

[0066] In the actual application process, the deficiency of the fixed-wiring battery equalization method in Embodiment 1 lies in that: it is necessary to provide wiring harnesses for each battery. Considering that the frequency of charge replenishment operations is not high, designing a large number of wiring harnesses increases the system complexity, and the charge replenishment range is restricted by the length of the wiring harnesses, resulting in inflexible operations. Based on this, the present application proposes Embodiment 2, namely a movable battery equalization method, which is different in that the digital energy exchange unit 1 does not provide the equalization module 13 and the measurement module 12, but adds a wireless communication module 18 and a charge replenishment robot 17. The digital energy management module 15 communicates with the charge replenishment robot 17 through the wireless communication module 18, sends a charge replenishment instruction to the charge replenishment robot 17, and the charge replenishment robot 17 realizes the charge replenishment operation. Considering the mobility of the charge replenishment robot 17 and the low frequency of charge replenishment operations, the charge replenishment robot 17 can realize the charge replenishment operation of a large-scale energy storage system, achieving a higher equipment reuse rate. At the same time, since the robot can be operated through voice commands, in addition to being controlled by the digital energy management module 15, the charge replenishment robot 17 can also be directly controlled by an operator through a terminal. The charge replenishment robot 17 includes a battery module, a positioning and mapping module, a charge replenishment robotic arm, an equalization control module, a large language model, and a wireless communication module 18. Among them, the battery module is responsible for providing power supply for the charge replenishment robot 17 and supporting the automatic charging function. The positioning and mapping module realizes functions such as environmental map construction, robot position positioning, and visual positioning, providing support for the robot to locate the position and contacts of the target charge replenishment battery pack 221. The charge replenishment robotic arm is responsible for connecting the positive and negative electrodes of the battery and performing the charge replenishment operation, and the equalization control module realizes an accurate charge replenishment control process. The large language model is responsible for receiving charge replenishment operation instructions, generating a charge replenishment action process, and calling each functional module to complete the entire charge replenishment process according to the process. In addition, in Embodiment 2, when a BMS is provided in each battery pack 221, the receiving module 16 can also be used to directly obtain the battery data in the battery, namely voltage and temperature, which will not be elaborated here.

[0067] The technical effects of the present application are as follows:

[0068] This application proposes a low-cost energy storage solution based on retired or standby battery packs. A series circuit is formed by multiple battery packs and a relay dedicated to high-voltage direct current is connected in series to construct an energy storage unit. Multiple such energy storage units are obtained. Measurement points are provided at both the positive and negative terminals of the battery packs for online real-time detection of the terminal voltage and temperature of the battery packs, and for testing the open-circuit voltage in the offline state. At the same time, an automated charging operation is provided in the offline state. The charging operation can be carried out in real time through a fixed cable by a digital energy exchange unit, or by issuing commands to a movable charging robot to execute the charging operation. The series circuit composed of multiple battery packs and relays is connected to an energy storage converter to achieve a low-cost string topology structure, improve the reusability during battery equalization, and at the same time reduce the sorting requirements for battery packs. A time-sharing measurement device and method are provided to reduce the measurement cost, and the cell-level measurement data collected by the BMS supporting the battery pack can be used for measurement. A method for real-time detection of the battery pack status and control of relay switch disconnection is provided to prevent and control the risk of thermal runaway. This application improves the reliability and reusability during battery equalization, reduces the usage rate of power components and the battery equalization cost, and time-sharing data acquisition and control reduce the energy consumption of battery equalization. In addition, each component adopts a modular design, which is convenient for quick replacement and substitution as needed, reduces the long-term operation and maintenance cost of the system, and realizes the large-scale promotion and deployment of battery packs.

[0069] Embodiment 2, as Figure 4 shown, this application also discloses a high-reusability battery pack equalization method. The high-reusability battery pack equalization method is applied to the above high-reusability battery pack equalization system. The high-reusability battery pack equalization method includes:

[0070] When the battery cluster 22 enters the offline measurement state, the relay 23 is disconnected through the digital energy exchange unit 1, and the maximum open-circuit voltage, minimum open-circuit voltage, and temperature of each battery pack 221 are obtained.

[0071] When the battery cluster 22 enters the online measurement state, the relay 23 is closed through the digital energy exchange unit 1, and the working voltage and temperature of each battery pack 221 are obtained.

[0072] When the battery cluster 22 enters the online charge and discharge state, the relay 23 is closed through the digital energy exchange unit 1, and the energy storage converter 21 is controlled to charge and discharge the battery cluster 22.

[0073] When the battery cluster 22 enters the offline charging state, the relay 23 is disconnected through the digital energy exchange unit 1, and the target battery pack 221 is equalized and charged; the target battery pack 221 is the battery pack 221 with an open-circuit voltage difference ratio greater than a preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage.

[0074] When the voltage or temperature of the battery pack 221 is abnormal, the corresponding relay 23 is disconnected through the digital energy exchange unit 1.

[0075] During the actual application process, as Figure 5 shown, the process of performing grouped balancing on retired or standby battery packs 221 is as follows:

[0076] First step: Detect the retired or standby battery pack 221, repair it if there is a problem, and detect performance indicators such as battery capacity.

[0077] Second step: Sort the normal battery packs 221, string together the battery packs 221 with approximate capacity and open-circuit voltage to form a single-string battery cluster 22, connect the relay 23 switch in series, the relay 23 is in the open state, and connect it to the DC side of the PCS.

[0078] Third step: The digital energy exchange unit 1 connects the relay 23 control circuit of the battery cluster 22. If the battery pack 221 is equipped with a BMS, then connect to the BMS control interface. The digital energy exchange unit 1 connects the positive and negative detection wires of the battery pack 221. The digital energy exchange unit 1 operates online, and each module operates normally.

[0079] Fourth step: The digital energy exchange unit 1 detects and confirms that the voltages and temperatures of all battery packs 221 are normal values, closes the relay 23 switch, and the battery cluster 22 enters the online state. The digital energy exchange unit 1 continuously detects the working voltage and temperature of the battery pack 221. If the battery pack 221 is equipped with a BMS, then detect the cell voltage and temperature of the corresponding battery pack 221. The digital energy exchange unit 1 waits for the charging and discharging instructions issued by the superior management system.

[0080] Fifth step: The digital energy exchange unit 1 receives the charging and discharging instructions issued by the superior management system, enters the charging and discharging state, and returns to the online state after completing the charging and discharging.

[0081] Sixth step: After the predefined time to switch to the offline state arrives, the digital energy exchange unit 1 cuts off the relay 23 switch, and the battery cluster 22 switches from the online state to the offline state. After standing for a preset time (2 hours), the open-circuit voltage is detected.

[0082] Seventh step: If the voltage difference between the battery packs 221 in the battery cluster 22 is within the allowable range, the digital energy exchange unit 1 issues a relay 23 closing instruction, and the battery cluster 22 enters the online state. Otherwise, start the charging compensation operation. There are three modes of the charging compensation operation, which can be executed by the balancing module 13, the BMS, and the charging compensation robot 17 respectively.

[0083] Step 8: After completing the supplementary power operation, after standing for a preset time (2 hours), the digital energy exchange unit 1 detects the open-circuit voltage again. If the voltage difference between the battery packs 221 in the battery cluster 22 is within the allowable range, it returns to the online state. If the voltage difference condition is not met, the abnormal battery pack 221 needs to be disassembled and enter the maintenance process.

[0084] Embodiment 3. The present application further provides a computer device, which can be a server or a terminal, and its internal structure diagram can be as Figure 6 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store processed data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, the above-mentioned various methods are implemented.

[0085] Those skilled in the art can understand that Figure 6 the structure shown in

[0086] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0087] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0088] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A highly reusable battery pack balancing system, characterized in that, The high-reusability battery pack equalization system includes: a digital energy exchange unit and multiple energy storage units; One end of each of the energy storage units is connected to the power grid, and the other end is connected to the digital energy exchange unit; Each energy storage unit includes: an energy storage converter, a battery cluster, and a relay; the battery cluster includes: multiple battery packs connected in series in sequence; The AC terminal of the energy storage converter is connected to the power grid; The positive electrode of the battery cluster is connected to the positive electrode of the DC terminal of the energy storage converter, and the negative electrode of the battery cluster is connected to the positive electrode of the relay; the positive and negative electrodes of each battery pack in each battery cluster are both connected to the digital energy exchange unit; The negative electrode of the relay is connected to the negative electrode of the energy storage converter, and the normally open contact of the relay is connected to the digital energy exchange unit; The digital energy exchange unit is connected to the control terminal of the energy storage converter; the digital energy exchange unit is configured to, when the battery cluster enters the off-line measurement state, disconnect the relay, and obtain the maximum open-circuit voltage, minimum open-circuit voltage, and temperature of each battery pack; when the battery cluster enters the on-line measurement state, close the relay, and obtain the working voltage and temperature of each battery pack; when the battery cluster enters the on-line charge and discharge state, close the relay, and control the energy storage converter to charge and discharge the battery cluster; when the battery cluster enters the off-line charge replenishment state, disconnect the relay, and perform equalization charge replenishment on the target battery pack; when a voltage anomaly or temperature anomaly occurs in the battery pack, disconnect the corresponding relay; the target battery pack is the battery pack whose open-circuit voltage difference ratio is greater than a preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage.

2. The high-reuse battery pack equalization system according to claim 1, characterized in that, When no BMS is provided in each battery pack, the digital energy exchange unit includes: an interface module, a measurement module, an equalization module, a protection module, and a digital energy management module; The interface module is respectively connected to the control terminals of all the energy storage converters; The measurement module is respectively connected to the positive and negative electrodes of all the battery packs; The equalization module is respectively connected to the positive and negative electrodes of all the battery packs; The protection module is respectively connected to the normally open contacts of all the relays; The digital energy management module is respectively connected to the interface module, the measurement module, the equalization module, and the protection module; when the battery cluster enters the offline measurement state, the digital energy management module is configured to control the protection module to disconnect the relay, and control the measurement module to collect the maximum open-circuit voltage, the minimum open-circuit voltage, and the temperature of each battery pack; when the battery cluster enters the online measurement state, control the protection module to close the relay, and control the measurement module to collect the working voltage and temperature of each battery pack; when the battery cluster enters the online charge and discharge state, control the protection module to close the relay, and control the energy storage converter to charge and discharge the battery cluster; when the battery cluster enters the offline charge replenishment state, control the protection module to disconnect the relay, and control the equalization module to perform equalization charge replenishment on the target battery pack; when a voltage anomaly or a temperature anomaly occurs in the battery pack, control the protection module to disconnect the corresponding relay.

3. The high-reuse battery pack balancing system according to claim 1, characterized in that When a BMS is provided in each battery pack, the digital energy exchange unit includes: an interface module, a receiving module, an equalization module, a protection module, and a digital energy management module; The interface module is respectively connected to the control terminals of all the energy storage converters; The receiving module is respectively connected to the positive and negative electrodes of all the battery packs; The equalization module is respectively connected to the positive and negative electrodes of all the battery packs; The protection module is respectively connected to the normally open contacts of all the relays; The digital energy management module is respectively connected to the interface module, the receiving module, the equalization module, and the protection module; when the battery cluster enters the offline measurement state, the digital energy management module is configured to control the protection module to disconnect the relay, and control the receiving module to receive the maximum open-circuit voltage, the minimum open-circuit voltage, and the temperature collected by the BMS of each battery pack; when the battery cluster enters the online measurement state, control the protection module to close the relay, and control the receiving module to receive the working voltage and temperature collected by the BMS of each battery pack; when the battery cluster enters the online charge and discharge state, control the protection module to close the relay, and control the energy storage converter to charge and discharge the battery cluster; when the battery cluster enters the offline charge replenishment state, control the protection module to disconnect the relay, and control the equalization module to perform equalization charge replenishment on the target battery pack; when a voltage anomaly or a temperature anomaly occurs in the battery pack, control the protection module to disconnect the corresponding relay.

4. The high-reuse battery pack balancing system according to claim 1, characterized in that, The digital energy exchange unit includes: an interface module, a measurement module, an equalization module, a protection module, a digital energy management module, a charge replenishment robot, and a wireless communication module; The interface module is respectively connected to the control terminals of all the energy storage converters; The measurement module is respectively connected to the positive and negative electrodes of all the battery packs; The charge replenishment robot is respectively connected to the positive and negative electrodes of all the battery packs, and the charge replenishment machine is connected to the wireless communication module through a wireless network; The protection module is respectively connected to the normally open contacts of all the relays; The digital energy management module is respectively connected to the interface module, the measurement module, the charging robot, the protection module and the wireless communication module; the digital energy management module is used to control the protection module to disconnect the relay when the battery cluster enters the offline measurement state, and control the measurement module to collect the maximum open-circuit voltage, the minimum open-circuit voltage and the temperature of each battery pack; when the battery cluster enters the online measurement state, control the protection module to close the relay, and control the measurement module to collect the working voltage and temperature of each battery pack; when the battery cluster enters the online charge and discharge state, control the protection module to close the relay, and control the energy storage converter to charge and discharge the battery cluster; when the battery cluster enters the offline charging state, control the protection module to disconnect the relay, and control the charging robot to perform equalizing charge on the target battery pack through the wireless communication module; when a voltage abnormality or a temperature abnormality occurs in the battery pack, control the protection module to disconnect the corresponding relay.

5. The high-reuse battery pack balancing system according to claim 1, wherein, The preset value is 1%.

6. The high-reuse battery pack balancing system according to claim 1, wherein The relay is a high-voltage DC relay.

7. The high-reuse battery pack equalization system according to claim 1, wherein The voltage range of the DC side of the energy storage converter is 600V - 1500V.

8. The high-reuse battery pack equalization system according to claim 1, characterized in that, The battery pack is a retired battery pack or a backup battery pack.

9. A high-reusability battery pack equalization method, characterized in that The high-reusability battery pack equalization method is applied to the high-reusability battery pack equalization system according to any one of claims 1-8. The high-reusability battery pack equalization method includes: When the battery cluster enters the offline measurement state, disconnect the relay through the digital energy exchange unit, and obtain the maximum open-circuit voltage, the minimum open-circuit voltage and the temperature of each battery pack; When the battery cluster enters the online measurement state, close the relay through the digital energy exchange unit, and obtain the working voltage and temperature of each battery pack; When the battery cluster enters the online charge and discharge state, close the relay through the digital energy exchange unit, and control the energy storage converter to charge and discharge the battery cluster; When the battery cluster enters the offline charging state, disconnect the relay through the digital energy exchange unit, and perform equalizing charge on the target battery pack; the target battery pack is the battery pack with an open-circuit voltage difference ratio greater than the preset value; the open-circuit voltage difference ratio is the difference ratio between the maximum open-circuit voltage and the minimum open-circuit voltage; When a voltage abnormality or a temperature abnormality occurs in the battery pack, disconnect the corresponding relay through the digital energy exchange unit.

10. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the high-reusability battery pack equalization method described in claim 9.

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