Analysis of automobile cr2032 button battery management system

　　Battery Management System (BMS) has become a hot topic as lithium batteries are increasingly used in different industries and products. This article mainly outlines its application in electric vehicles, mainly introducing the role, architecture and design considerations of BMS. , Battery Management System (BMS) has become a hot topic as lithium batteries are increasingly used in different industries and products. This article mainly outlines its application in electric vehicles, mainly introducing the role, architecture and design considerations of BMS.

　　Analysis of automobile cr2032 button battery management system

　　Battery Management System (BMS) has become a hot topic as lithium batteries are increasingly used in different industries and products. This article mainly outlines its application in electric vehicles, mainly introducing the role, architecture and design considerations of BMS.

　　Among China's electric vehicle standards, there is a recommended national standard "Technical Conditions for Battery Management Systems for Electric Vehicles" that is being submitted for approval. This standard defines many BMS functional requirements, which are divided into general requirements and technical requirements. General requirements include battery data collection, information transmission and safety management. Specifically, it includes detection of battery data related to heat and electricity (voltage, current and temperature and other parameters)) real-time estimation of state of charge (SOC)) and battery system Carry out fault diagnosis, including fault handling mechanism) Realize information interaction with other vehicle controllers through the bus) Realize control and management of the charging process through communication with charging equipment. Technical requirements include insulation resistance, insulation withstand voltage performance, battery system status monitoring, SOC estimation, battery fault diagnosis, and safety protection. It also defines operating conditions including over-voltage operation, under-voltage operation, high-temperature operation, low-temperature operation, high-temperature resistance performance, Low temperature resistance, salt spray resistance, moisture and heat resistance, vibration resistance, power supply polarity reversal resistance and electromagnetic radiation immunity, etc.

　　The above standard definition may make the concept of BMS somewhat vague. Another classification may be more precise:

　　1. Monitoring: BMS monitors the condition of battery cells and battery packs by detecting physical parameters in the battery pack. Since the general battery pack requires a thermal system, flow as an important parameter) state of charge (SOC) and battery state of health (SOH) should theoretically be placed in the monitoring content, although it is desired to conclude that both states are Requires more data and calculation support.

　　2. Calculation: The real calculation is actually the battery usage limit based on the monitored status under the vehicle controller. For example, under different SOC, the maximum charging power and discharge power of the battery have different limits. Electric vehicles need to calculate and count battery usage. They need to count the energy used in a single time, the total energy used after the first use, and the time since the first use to evaluate the vehicle's electric driving range and battery life.

　　3. Communication: Both internal and external BMS need to send data through communication. Aggregating battery and vehicle data wirelessly and wiredly is a basic requirement for BMS communication. In the field of electric vehicle charging, DC fast charging, vehicle and grid power exchange (V2G), and vehicle and home power exchange (V2H), the communication function of BMS plays a vital role in these future expanded functions.

　　4. Protection: This content covers fault diagnosis and processing, including overvoltage, undervoltage, overcurrent, low temperature, high temperature and short circuit. This part of the content has been regarded as the basic content of the BMS, but it is closely related to the characteristics of the battery cells. When troubleshooting, the BMS is often required to configure switches and cooling systems, but the important point is to balance battery safety and vehicle operation safety. If the BMS suddenly performs some operations without considering the safety of the car, it will bring very bad results.

　　5. Optimization: This content involves battery pack balancing, battery capacity calculation and other life optimization. After the car leaves the factory and is used, as the number of charging times increases and the use time prolongs, it is an important job of the BMS to regularly analyze the changes in battery status through a series of parameters.

　　Of course, in the BMS, high-voltage interlocking, insulation detection or other functions may need to be added due to the safety requirements of the entire electric vehicle. These parts can be considered as safety features common to all high-voltage related components and can be listed separately. 4R.^*9D(amp)i3Z0?6H

　　A typical BMS system can be divided into internal architecture and external architecture

　　It can be divided into:

　　1. Signal conditioning part: single voltage, module voltage, battery pack voltage, current and temperature sensors, flow sensors, insulation detection and other signal conditioning circuits, usually located on the sub-module and main module respectively.

　　2. Control drive part: control parts such as positive relay, negative relay, heating device driver, heat sink driver and high-voltage interlock.

　　3. Generally only controlled by the main module.

　　4. Power supply and clock part: Since the BMS has high voltage and 12V low voltage, you need to pay attention to the isolation problem first.

　　5. Processing part: This part is basically the work of control strategies and algorithms.

　　7 can be divided into the following three parts:

　　1. Mechanical connection: Depending on the number and arrangement of battery cells, the BMS can be distributed or centralized. This will involve the fixation of main modules and sub-modules. The mechanical connection of the entire battery pack system is often a key consideration in the design of electric vehicles. Analysis of force and vibration, as well as mass configuration such as climbing, are also considerations.

　　2. Data communication: This refers to the actual bus interface, generally high-speed and low-speed CAN. In the future implementation of smart grid systems, wired interfaces such as power line carrier communications (PLC) and wireless interfaces such as Zigbee may be configured. The battery pack designed by the State Grid is also equipped with circuit modules such as GPS. '

　　3. Physical connection: The voltage, temperature measurement sensor and current sensor on the positive and negative electrodes of the single battery all need to be directly physically connected to the BMS. This part seems simple but is full of wisdom.

　　The external architecture is the cornerstone of how the BMS works with the battery system and other components, and cannot be left sloppy.

　　In order to meet the usage habits of traditional drivers, HEV, PHEV, EREV and EV are all designed according to the basic requirements of ordinary cars, so that the improved power system and basic driving conditions need to be significantly different from the original internal combustion engine cars. similarity. Based on driving conditions based on European NEDC, ECE15, EUDC, American FTP72, FTP75, SFTP, US06, SFTP, SC03 and Japanese 10-15 Mode, the actual working conditions of the battery pack can be obtained through the conditions of the entire vehicle. In many laboratories, you can see the data obtained based on such vehicle test platforms, and the actual working environment of BMS is based on these abstracted typical working conditions.

　　A very important factor that distinguishes electric vehicles from other electrical equipment is that they require both high power and a lot of energy. High power means large current, which means it is difficult to accurately measure current at low cost. High energy means huge battery capacity and quantity, both of which have high safety requirements for battery packs. A series of combinations of factors make automotive BMS involve many things. What is described here are some personal opinions. I hope to discuss this field with everyone.

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