Battery management control method

Abstract

The invention discloses a battery management control method, and relates to the field of intelligent power grids, and the method comprises the steps: a battery array management unit detects the number of battery cluster management units which start to work; when all M battery cluster management units start to work, the battery array management unit controls full-power charging and discharging; when the number of the working battery cluster management units is smaller than M, the battery array management unit controls the charging and discharging power according to the number of the battery cluster management units starting to work; when the number of the working battery cluster management units is smaller than a preset value N, the battery array management unit controls not to charge and discharge; after the battery cluster management unit detects the working state of the battery cluster management unit, the relays of all the battery cluster management units are controlled to be closed; when the battery array management unit detects that the voltage difference between the maximum total voltage and the minimum total voltage of the current battery pack exceeds an allowable value, the battery array management unit reports a fault that the total voltage difference is large. And the battery system is effectively controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and in particular to a battery management control method. Background Art

[0002] The common characteristics of distribution substations are wide coverage, long power supply lines, relatively scattered power supply areas, small and unstable load density. There are currently long-term overloads in the substations, long-term overloads on the distribution substation side, long-term seasonal overloads of distribution transformers, short-term seasonal overloads of distribution transformers, random and frequent overloads of distribution transformers, low voltage on the user side, and new energy access.

[0003] In the related art, the energy storage batteries in the substation area have the problems of low battery safety, low environmental adaptability, short battery life, and inability to effectively control and monitor the battery system in real time according to a specific control strategy. Based on this, a battery management control method is provided. Summary of the invention

[0004] The present invention provides a battery management control method, which solves the technical problem that a station area cannot effectively control and monitor a battery system according to a specific control strategy in real time.

[0005] According to one aspect of the present disclosure, a battery management control method is provided, the method comprising: The battery array management unit detects the number of battery cluster management units that have started to work; When all the M battery cluster management units start working, the battery array management unit controls full-power charging and discharging; When the number of working battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of working battery cluster management units; When the number of working battery cluster management units is less than the preset value N, the battery array management unit controls not to charge or discharge; When the battery cluster management unit detects the working state of the battery cluster management unit, it detects and determines that the pressure difference between the maximum total pressure and the minimum total pressure of the battery group is less than the maximum total pressure difference allowed by the battery group, and then controls the relays of all battery cluster management units to close; When the battery array management unit detects that the pressure difference between the maximum total pressure and the minimum total pressure of the current battery group exceeds the allowable value, the battery array management unit reports a total pressure difference large fault.

[0006] In a possible implementation, the method further includes: before each closing of the relay switch, the capacitors in the high-voltage system connected to the battery cluster are pre-charged, and when the battery array management unit performs pre-charging control, it first controls each battery cluster management unit to close the pre-charging relay switch; when the battery cluster management unit detects that the pre-charging time is greater than a preset value, the battery cluster management unit reports that the pre-charging is completed, and when the battery array management unit detects that all capacitors are pre-charged, it controls to disconnect the pre-charging circuit.

[0007] In a possible implementation, the excess energy in the battery is consumed by energy balancing, or by transferring the energy of a single battery with high energy to a single battery with low energy.

[0008] In a possible implementation, the method further includes: When the cell voltage is charged to the first preset cell voltage, a current reduction request is made according to the current charging current of the energy storage converter; After reaching the first preset single cell voltage multiple times, the current will reach the minimum limit charging current, and the control will no longer reduce the current, maintaining the energy storage converter charging until the charging reaches the second preset single cell voltage, the charging limit current is limited to 0, and the energy storage converter stops charging.

[0009] In a possible implementation, the method further includes: when the cell voltage is set to a third preset cell voltage, making a current reduction request according to a current discharge current of the energy storage converter; After reaching the third preset single cell voltage multiple times, the current will reach the minimum limit discharge current, control the current reduction, and maintain the energy storage converter discharge until the discharge reaches the fourth preset single cell voltage, the discharge limit current is limited to 0, and the energy storage converter stops discharging.

[0010] In a possible implementation, when the number of operating battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of operating battery cluster management units, including: controlling the charging and discharging power by controlling the charging and discharging current.

[0011] In a possible implementation, the method further includes: During the charging and discharging process, if the working current exceeds the safe value, measures are taken to limit the current growth. The current protection includes battery cluster charging overcurrent protection and battery cluster discharging overcurrent protection; During the charging and discharging process, when the voltage exceeds the set value, measures are taken to limit the voltage. The voltage exceeding the set value includes: the battery cluster voltage is too high or too low, the single cell voltage is too high or too low, and the single cell voltage difference is too large.

[0012] In a possible implementation, the method further includes: When the battery temperature exceeds the limit value, protective measures are taken for the battery. Temperature protection includes single cell over-temperature protection, single cell under-temperature protection, single cell temperature difference protection, and pole over-temperature protection. When the remaining battery power is lower than the set value, the battery discharge is restricted.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The battery management control method of the disclosed embodiment is capable of real-time monitoring and collecting the state parameters of the battery module, and performing necessary calculations and processing on the relevant state parameters to obtain more system parameters, and effectively control the battery system according to a specific control strategy. At the same time, the BMS can exchange information with other external devices (converters, energy management units, fire protection, etc.) through its own communication interface and analog / digital input and output interface to form a linkage of the entire energy storage system, and utilize all system components through reliable physical and logical connections to efficiently and reliably complete the monitoring of the entire energy storage system. The battery cluster management unit is responsible for the management of all battery management units in a battery cluster, and also has the functions of current collection, total voltage collection, insulation resistance detection, SOC estimation, etc. of the battery cluster, and when a fault occurs in the battery cluster, the DC contactor is tripped to make the battery cluster exit operation and ensure battery safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram showing the connection between a battery management system, a power storage converter system PCS and an energy management system EMS according to an embodiment of the present disclosure is shown.

[0015] Figure 2 A flowchart of a battery management control method according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0016] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0017] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0018] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0019] As the core component of the battery system, the energy storage battery management system is the bridge between the battery pack and external devices, which determines the utilization rate of the battery. Its performance is very important to the cost and safety performance of the energy storage system. The topology configuration of the energy storage battery management system should match the topology of the energy storage converter (power storage system, PCS) and the battery grouping method, such as Figure 1 shown.

[0020] The battery management system consists of three parts: Battery Management Unit (BMU), Battery Cluster Management Unit (BCU), and Battery Array Management Unit (BAU). BMU is responsible for the management of battery cells and battery modules, integrating the functions of voltage, temperature and other information collection, balancing, information transmission, thermal management, etc. of each single battery. BCU is responsible for the management of all BMUs in a battery cluster, and also has the functions of current collection, total voltage collection, insulation resistance detection, SOC estimation, etc. of the battery cluster, and when a battery cluster fails, it will trip the DC contactor to make the battery cluster exit operation to ensure battery safety. BAU performs numerical calculation, performance analysis, and data storage on the data uploaded by BMU and BCU, and exchanges information with PCS and monitoring background. BAU is equipped with a display screen to realize functions such as battery information, parameter configuration, and fault alarm display. The monitoring background controls the inverter to effectively charge and discharge the battery group based on the various information uploaded by BAU, so as to achieve the functions of peak and frequency regulation, peak shaving and valley filling, and power output.

[0021] According to one aspect of the present disclosure, a battery management control method is provided, the method comprising: S01, the battery array management unit detects the number of battery cluster management units that have started working; S02, when all the M battery cluster management units start working, the battery array management unit controls full power charging and discharging; S03, when the number of working battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of working battery cluster management units; S04, when the number of working battery cluster management units is less than a preset value N, the battery array management unit controls not to charge or discharge; S05, after the battery cluster management unit detects the working state of the battery cluster management unit, it detects and determines that the pressure difference between the maximum total pressure and the minimum total pressure of the battery group is less than the maximum total pressure difference allowed by the battery group, and then controls the relays of all battery cluster management units to be closed; S06, when the battery array management unit detects that the pressure difference between the maximum total pressure and the minimum total pressure of the current battery group exceeds the allowable value, the battery array management unit reports a total pressure difference large fault.

[0022] For example, when the BAU passes the in-place detection, the total pressure difference is judged. When the pressure difference between the maximum total pressure and the minimum total pressure of the battery pack is less than the maximum total pressure difference allowed for the battery pack to be energized, the BMS determines that the pressure difference of all in-place battery packs is small and meets the relay energization conditions, then closes all BCU main negative relays and enters the pre-charge equalization process. When the BAU detects that the current in-place total pressure difference exceeds the allowable value, the BAU reports a total pressure difference fault, requiring manual intervention to shut down the faulty battery pack, or enable maintenance mode to manually balance the battery pack.

[0023] In a possible implementation, the method further includes: before each closing of the relay switch, the capacitors in the high-voltage system connected to the battery cluster are pre-charged, and when the battery array management unit performs pre-charging control, it first controls each battery cluster management unit to close the pre-charging relay switch; when the battery cluster management unit detects that the pre-charging time is greater than a preset value, the battery cluster management unit reports that the pre-charging is completed, and when the battery array management unit detects that all capacitors are pre-charged, it controls to disconnect the pre-charging circuit.

[0024] In a possible implementation, the excess energy in the battery is consumed by energy balancing, or by transferring the energy of a single battery with high energy to a single battery with low energy.

[0025] The parameters of the battery, such as capacity, internal resistance and voltage, cannot be completely consistent. The tiny internal performance differences between battery cells will continue to accumulate with the charging and discharging operation, and will be clearly reflected in the defects such as poor consistency of the battery system, degradation of the charging and discharging performance of the battery system, and significant attenuation of the available capacity of the battery system. Balancing control performs balanced charging between batteries according to the battery voltage, which can improve the consistency of the grouped batteries and alleviate the problem of battery system performance degradation caused by the battery short board effect. Balancing control is divided into passive balancing and active balancing. Passive balancing is a resistance energy consumption type. A resistor shunt is connected in parallel to each single cell. Energy consumption balancing is to consume the excess energy in the battery to achieve voltage balance of the entire group of batteries. Active balancing is an energy transfer type, which transfers the high energy of the single cell to the low energy of the single cell, or uses the energy of the entire group to supplement the lowest single cell. During the implementation process, an energy storage link is required so that the energy can be redistributed through this link.

[0026] In a possible implementation, the method further includes: When the cell voltage is charged to the first preset cell voltage, a current reduction request is made according to the current charging current of the energy storage converter; After reaching the first preset single cell voltage multiple times, the current will reach the minimum limit charging current, and the control will no longer reduce the current, maintaining the energy storage converter charging until the charging reaches the second preset single cell voltage, the charging limit current is limited to 0, and the energy storage converter stops charging.

[0027] When the system is running, the voltage of each cell and the temperature of the battery pack are monitored in real time. The upper limit voltage value of charging, the lower limit voltage value of discharging, the maximum chargeable current, and the maximum dischargeable current are evaluated according to the battery system status and sent to the PCS through a message. The PCS performs charge and discharge operations to control the charge and discharge currents so that they cannot exceed the maximum value requested by the BMS. In charging mode: When the cell voltage is charged to the first preset cell voltage, the BMS makes a current reduction request based on the current PCS charging current. After reaching the first preset cell voltage multiple times, the current will reach the minimum limit charging current, and the BMS will no longer control the current reduction and maintain PCS charging until the charging reaches the second preset cell voltage. The BMS will set the full flag, the charging limit current limit is 0, and the PCS stops charging.

[0028] In a possible implementation, the method further includes: when the cell voltage is set to a third preset cell voltage, making a current reduction request according to a current discharge current of the energy storage converter; After reaching the third preset single cell voltage multiple times, the current will reach the minimum limit discharge current, control the current reduction, and maintain the energy storage converter discharge until the discharge reaches the fourth preset single cell voltage, the discharge limit current is limited to 0, and the energy storage converter stops discharging.

[0029] When the cell voltage is lowered to the third preset cell voltage, the BMS makes a current reduction request based on the current PCS discharge current. When the third preset cell voltage is reached multiple times, the current will reach the minimum limit discharge current, and the BMS will no longer control the current reduction and maintain PCS discharge until the discharge reaches the fourth preset cell voltage. The BMS will set the empty flag, the discharge limit current is limited to 0, and the PCS stops discharging.

[0030] In a possible implementation, when the number of operating battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of operating battery cluster management units, including: controlling the charging and discharging power by controlling the charging and discharging current.

[0031] Battery safety protection is the most important function of the battery management system. The battery management system monitors and analyzes the battery status to protect the battery from various abnormal conditions during operation, and can send out alarm signals or trip commands to implement local fault isolation. The battery management system includes current protection, voltage protection, temperature protection, and SOC protection.

[0032] In a possible implementation, the method further includes: During the charging and discharging process, if the working current exceeds the safe value, measures are taken to limit the current growth. The current protection includes battery cluster charging overcurrent protection and battery cluster discharging overcurrent protection; During the charging and discharging process, when the voltage exceeds the set value, measures are taken to limit the voltage. The voltage exceeding the set value includes: the battery cluster voltage is too high or too low, the single cell voltage is too high or too low, and the single cell voltage difference is too large.

[0033] In a possible implementation, the method further includes: When the battery temperature exceeds the limit value, protective measures are taken for the battery. Temperature protection includes single cell over-temperature protection, single cell under-temperature protection, single cell temperature difference protection, and pole over-temperature protection. When the remaining battery power is lower than the set value, the battery discharge is restricted.

[0034] It can realize fast charging and discharging of batteries, improve battery utilization and life. At the same time, it can also monitor the battery status in real time and report the battery status to the power grid cloud platform to prevent battery failure, and support control strategies such as peak shaving and valley filling, and emergency power protection.

[0035] The control strategy issued by the dispatching platform is updated in real time to the BMS internal system to implement one strategy for each area; the battery's requestable charging and discharging power is adjusted in real time based on the current EMS system decision or the dispatching platform's control command, as well as the battery's current status; all system status information is open to the fusion terminal, and the dispatching platform can make a more accurate assessment of the battery status based on the real data of the BMS system.

[0036] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of the module, program segment or instruction includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of special hardware and computer instructions.

[0037] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A battery management control method, characterized in that: The method comprises: The battery array management unit detects the number of battery cluster management units that have started to work; When all the M battery cluster management units start working, the battery array management unit controls full-power charging and discharging; When the number of working battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of working battery cluster management units; When the number of working battery cluster management units is less than the preset value N, the battery array management unit controls not to charge or discharge; When the battery cluster management unit detects the working state of the battery cluster management unit, it detects and determines that the pressure difference between the maximum total pressure and the minimum total pressure of the battery group is less than the maximum total pressure difference allowed by the battery group, and then controls the relays of all battery cluster management units to close; When the battery array management unit detects that the pressure difference between the maximum total pressure and the minimum total pressure of the current battery group exceeds the allowable value, the battery array management unit reports a total pressure difference large fault.

2. A battery management control method according to claim 1, characterized in that: The method further includes: before each closing of the relay switch, the capacitors in the high-voltage system connected to the battery cluster are pre-charged, and when the battery array management unit performs pre-charging control, it first controls each battery cluster management unit to close the pre-charging relay switch; when the battery cluster management unit detects that the pre-charging time is greater than a preset value, the battery cluster management unit reports that the pre-charging is completed, and when the battery array management unit detects that all capacitors are pre-charged, it controls to disconnect the pre-charging circuit.

3. A battery management control method according to claim 1, characterized in that: Excess energy in the battery is consumed through energy balancing, or by transferring energy from a single cell with high energy to a single cell with low energy.

4. A battery management control method according to claim 1, characterized in that: The method further comprises: When the cell voltage is charged to the first preset cell voltage, a current reduction request is made according to the current charging current of the energy storage converter; After reaching the first preset single cell voltage multiple times, the current will reach the minimum limit charging current, and the control will no longer reduce the current, maintaining the energy storage converter charging until the charging reaches the second preset single cell voltage, the charging limit current is limited to 0, and the energy storage converter stops charging.

5. A battery management control method according to claim 1, characterized in that: The method further includes: when the cell voltage is lowered to a third preset cell voltage, making a current reduction request according to the current discharge current of the energy storage converter; After reaching the third preset single cell voltage multiple times, the current will reach the minimum limit discharge current, control the current reduction, and maintain the energy storage converter discharge until the discharge reaches the fourth preset single cell voltage, the discharge limit current is limited to 0, and the energy storage converter stops discharging.

6. A battery management control method according to claim 1, characterized in that: When the number of operating battery cluster management units is less than M, the battery array management unit controls the charging and discharging power according to the number of operating battery cluster management units, including: controlling the charging and discharging power by controlling the charging and discharging current.

7. A battery management control method according to claim 1, characterized in that: The method further comprises: During the charging and discharging process, if the working current exceeds the safe value, measures are taken to limit the current growth. The current protection includes battery cluster charging overcurrent protection and battery cluster discharging overcurrent protection; During the charging and discharging process, when the voltage exceeds the set value, measures are taken to limit the voltage. The voltage exceeding the set value includes: the battery cluster voltage is too high or too low, the single cell voltage is too high or too low, and the single cell voltage difference is too large.

8. A battery management control method according to claim 1, characterized in that: The method further comprises: When the battery temperature exceeds the limit value, protective measures are taken for the battery. Temperature protection includes single cell over-temperature protection, single cell under-temperature protection, single cell temperature difference protection, and pole over-temperature protection. When the remaining battery power is lower than the set value, the battery discharge is restricted.

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