CN213782928U

CN213782928U - Battery management system for energy storage of lithium battery

Info

Publication number: CN213782928U
Application number: CN202022863851.2U
Authority: CN
Inventors: 张怀
Original assignee: Wuhu Churui Intelligent Technology Co ltd
Current assignee: Wuhu Churui Intelligent Technology Co ltd
Priority date: 2020-12-03
Filing date: 2020-12-03
Publication date: 2021-07-23
Anticipated expiration: 2030-12-03

Abstract

The utility model relates to a battery management system for lithium cell energy storage. The battery pack comprises a battery pack, a PC (personal computer), a battery control unit, a plurality of battery monitoring units, a high-voltage unit and a remote terminal module. The battery management system monitors parameters such as open-circuit voltage and temperature of the battery pack in real time through the BMU, and sends the parameters to the BCU through the CAN bus in real time after being converted by the MCU in the BMU. Meanwhile, the high-voltage unit HVU measures the total voltage, the current and the insulation resistance state of the battery pack and sends the state to the battery control unit BCU. And then the BCU estimates the state information of the single batteries of the battery pack, such as SOC, SOH and the like, further makes a balance decision, and controls a charger to connect the battery system into a power grid and to connect a load. The battery management system for lithium battery energy storage is convenient for managers to know and master the state of the battery system in real time, improves the working performance and the overall efficiency of the energy storage system, improves the safety and the reliability of the system, and reduces the cost.

Description

Battery management system for energy storage of lithium battery

Technical Field

The utility model belongs to the technical field of the lithium cell, concretely relates to battery management system for lithium cell energy storage.

Background

Under the background that the problems of energy shortage and environmental protection are gradually valued, the lithium battery energy storage system is valued by novel strategic industries of many countries. The lithium battery group operation has some defects of service life and safety due to problems of production process, working environment and the like. Firstly, in practical application, due to improper management, the lithium iron phosphate battery is easy to cause overlong charging and discharging time, and the overcharge and overdischarge phenomena can cause irreversible damage to the lithium battery. Secondly, the high temperature can make the internal voltage of lithium cell improve rapidly, produces a large amount of heats, and the aggravation chemical reaction arouses electrolyte to decompose, causes the potential safety hazard easily. Finally, the problems of high voltage insulation of lithium batteries and balancing of single batteries are also the most notable problems in practical applications.

In order to meet the voltage and power requirements of product loads, the battery cells are often subjected to energy storage in groups of dozens or even hundreds in the energy storage application through series-parallel connection. Because the battery has production and processing errors in the manufacturing process, even if the battery monomer of the same model has certain difference in actual capacity. Secondly, the difference of various working environment factors (such as temperature) makes the discharge efficiency of each monomer different during the use process. Finally, the charge and discharge amount of the whole energy storage system is unbalanced, so that the charge and discharge efficiency of the energy storage system is too low, and even the monomer is over-charged and over-discharged to cause failure. In addition, along with the increasing production demand, the functions of monitoring, estimating and safety management of the battery state are also required to be enriched gradually. Therefore, scientific management and control in various aspects such as the electric quantity state and the temperature state in the working process of the lithium battery become a necessary trend for future development.

Disclosure of Invention

An object of the utility model is to provide a battery management system for lithium cell energy storage.

The utility model provides a battery management system for lithium cell energy storage comprises group battery, battery control unit BCU (Battery Controller Unit), battery monitoring unit BMU (Battery Monitor Unit), high Voltage unit HVU (high Voltage Unit), remote Terminal unit RTU (remote Terminal Unit) and PC, wherein:

the battery control unit, the battery monitoring unit, the high-voltage unit and the remote terminal unit are respectively in bidirectional connection with the CAN bus, and are respectively hung on the CAN bus as CAN nodes;

the PC is in bidirectional connection with the remote terminal unit;

the output end of the commercial power is connected with the power input end of the charger, the power output end of the charger is respectively connected with the battery pack and the input end of the load, the signal input end of the charger is connected with the output end of the battery control unit, and the high-voltage unit is connected in parallel with a power cable between the charger and the battery pack; the battery pack is provided with a plurality of batteries, each battery pack is internally provided with a battery monitoring unit, and signal wires are respectively led out from two ends of adjacent battery monomers, clustered and connected with a data acquisition port of the battery monitoring unit.

In the utility model, the charger converts the 220V alternating current of the commercial power into direct current to charge the battery pack; when the battery pack discharges, the direct current is converted into pure and stable alternating current to supply power to a load, and the mode conversion is controlled by the battery control unit;

in the utility model, 8-20 batteries are arranged in each battery pack.

The utility model discloses in, battery monitoring unit installs in the group battery, has a battery monitoring unit in every group battery.

And the battery control unit BCU is used for data communication and control. Before the whole battery management system runs, the system is initialized and historical data is read; when the battery pack monitoring unit BMU is operated, real-time data such as voltage, current, temperature, electric quantity and the like of any battery in each battery pack during charging and discharging are obtained; then controlling a battery pack monitoring unit to perform balance control on each battery pack according to the obtained data; when each battery pack reaches an equilibrium state, the battery control unit controls the rectifier to access the national power grid, and charging and discharging of the battery pack are completed.

The BMU has the functions of data acquisition and balanced execution; a plurality of are linked to each other with battery control unit through the bus mode in groups, when monitoring battery number surpass a group battery and hold quantity, expand step by step through bus type connected mode between the group battery monitoring unit to satisfy different scale battery energy storage system's supervisory control demand. The battery monitoring unit mainly comprises a data conversion chip and a multi-battery monitoring and equalizing chip, wherein each multi-battery monitoring and equalizing chip comprises a voltage signal acquisition and processing circuit, a temperature signal acquisition and processing circuit and a battery equalization control circuit, and is connected with each battery in the same battery pack. The data conversion chip receives various real-time data of the battery pack monitored by the multi-battery monitoring and balancing chip through an in-board communication protocol, mainly comprises open-circuit voltage of each battery in the pack and temperature information of a plurality of measuring points, converts the data into a CAN message format, and transmits the CAN message format to the battery control unit through a CAN bus to perform subsequent calculation, control and operation.

The high voltage unit HVU is responsible for monitoring states of total battery voltage, current, insulation resistance and the like of the battery pack, and the current can be collected by a Hall sensor or a shunt. And then the HVU sends the measured data to the BCU through the CAN bus to carry out the next calculation.

The remote Terminal unit RTU (remote Terminal Unit) is a special measurement and control unit with a modular structure designed for long communication distance and severe field environment, transmits data on a CAN bus to a remote PC (personal computer), has remote data acquisition, control and communication functions, and is responsible for transmitting historical data stored in a BMU and a BCU and operating instructions of the PC.

The battery pack serves as a controlled object. One battery pack may only contain one single cell, or may include a plurality of single cells. In a large energy storage system, as the capacity, voltage and current of a single battery are small, dozens or even hundreds of single batteries are required to achieve the required voltage and capacity grade through series-parallel combination, so that the energy transfer with an external network is realized. The most desirable management mode is to be able to monitor and control each cell. In order to improve the working efficiency of the system and the economy of hardware, the BMU and the battery can adopt a one-to-many supervision mode, namely, one battery monitoring unit simultaneously monitors the state parameters and controls the electric quantity balance of a plurality of battery monomers in the battery pack, and the monomers in the battery pack are connected in series. Considering the problems of accuracy and time consumption of battery state parameter sampling, the single battery pack is not suitable to be overlarge in size, and the number is preferably 8-20 as known from mainstream multi-battery monitoring and equalization chip model investigation.

The beneficial effects of the utility model reside in that:

1. and management personnel can conveniently know and master the state of the battery system in real time. The manager can monitor and manage the state parameters (voltage, current, electric quantity and temperature) of the battery in real time through the battery management system, and the battery management system is used for warning users and limiting excessive charging and discharging of the system so as to reduce battery damage and functional faults. In future application, managers can also read historical data stored in the BMS system, and can perform big data analysis and further algorithm optimization.

2. The working performance and the overall efficiency of the energy storage system are improved. The battery management system can effectively improve the service efficiency of the energy storage system and avoid causing energy secondary loss through real-time battery state monitoring, electric quantity balancing and working process control.

3. The safety and the reliability are improved, and the system cost is reduced. The battery management system monitors each single battery in the storage battery in real time, obtains the voltage value, the current value, the temperature and the like of the single battery, can find the battery in an abnormal state in time, realizes the adjustment of the residual electric quantity of the battery pack through strategies such as balance control and the like, and can prompt managers to replace the single battery in time when the battery is scrapped. The safety and the reliability are greatly improved. And on the basis of the passive equalization function of the original chip, the active equalization function can be expanded and realized, and the efficiency can be improved to a greater extent. The battery scrap cycle is prolonged, and the cost is greatly reduced.

Drawings

Fig. 1 is a frame diagram of the overall structure of a battery management system;

fig. 2 is a BMS system application single line diagram;

reference numbers in the figures: the system comprises a PC (personal computer) 1, a battery control unit 2, a battery monitoring unit 3, a high-voltage unit 4, a remote terminal unit 5, a battery pack 6 and a charger 7.

Detailed Description

The present invention is further described in the following by the embodiments, which are only a part of the embodiments described herein, and other embodiments without inventive labor, which are based on the present invention, will also belong to the protection scope of the present invention.

Example 1: the battery management system shown in fig. 1 and 2 is composed of a PC 1, a battery control unit 2, a battery monitoring unit 3, a high voltage unit 4, a remote terminal unit 5, a battery pack 6, and a charger 7.

The specific working process is as follows:

1. after the installation and deployment of the battery management system are completed, the PC 1 sends an instruction to the battery control unit 2, and then the battery monitoring unit 3 is used for measuring the open-circuit voltage and the temperature of the battery system under the battery management system;

2. when the battery pack 6 is charged and discharged, the battery monitoring unit 3 has the functions of data acquisition and balanced execution, wherein the measurement pins of the voltage signal acquisition circuit are respectively connected with the two ends of each battery monomer in parallel, and the temperature signal acquisition circuit measures the temperature of a plurality of points in the battery pack. After the battery monitoring unit 3 collects the relevant data, the data is converted into a CAN message through the MCU on the battery monitoring unit 3 and is sent to the CAN bus. And meanwhile, the high-voltage unit 4 measures the total voltage, current, insulation resistance and other information of the whole system and sends the information to the CAN bus. Subsequently, the battery control unit 2 receives data of each battery monitoring unit 3 and the high voltage unit 4, and performs SOC, SOH estimation of each battery cell. And simultaneously, the remote terminal module RTU sends the real-time data on the bus to the PC and displays the real-time data on a visual interface. Then, a balance control command is sent to the battery monitoring unit 3 according to the residual electric quantity among different batteries, and a battery balance control circuit in the balance control module is switched on, so that the batteries with more residual electric quantity are discharged, and the residual electric quantity of each battery monomer in the battery pack 6 is balanced; for the battery with the health state meeting the scrapping standard, the battery control unit 2 sends alarm information to the remote terminal unit 5 to inform the manager to replace the scrapped battery monomer. The remote terminal unit 5 sends the real-time data on the bus to the PC and displays it on the visual interface. Finally, the battery control unit 2 can control the charger 7 to connect the power grid and the load, and control the charging and discharging actions of the battery system.

It does to go up the utility model discloses a work flow to this technical field's technical personnel, the utility model discloses can have various changes and change. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a battery management system for lithium cell energy storage, comprises group battery, battery control unit, battery monitoring unit, high-pressure unit, remote terminal unit and PC, its characterized in that:

the PC is in bidirectional connection with the remote terminal unit;

2. The battery management system of claim 1, wherein the battery management system comprises: the charger converts 220V alternating current of the commercial power into direct current to charge the battery pack; when the battery pack discharges, the direct current is converted into pure and stable alternating current to supply power to the load, and the mode conversion is controlled by the battery control unit.

3. The battery management system of claim 1, wherein the battery management system comprises: 8-20 batteries are arranged in each battery pack.

4. The battery management system of claim 1, wherein the battery management system comprises: the battery monitoring units are mounted in battery packs, with one battery monitoring unit in each battery pack.