Typical power lithium battery management system -Lithium - Ion Battery Equipment
Lithium-ion batteries for electric vehicles have large capacity, many series and parallel cells, complex systems, high performance requirements such as safety, durability, and power, and are difficult to implement. Therefore, they have become a bottleneck affecting the popularization of electric vehicles. The safe working area of lithium-ion batteries is limited by the temperature and voltage windows. If the window is exceeded, the performance of the battery will decline rapidly, and even safety problems will occur.
When the temperature is too high, it will adversely affect the life of the battery. When the temperature is high to a certain level, it may cause safety problems, which will cause lithium metal to form an electroplating layer on the surface of the negative electrode, which will reduce the cycle life of the battery.
Too low voltage or over-discharge will cause the electrolyte to decompose and produce flammable gas, which will lead to potential safety risks. Excessive voltage or overcharge may cause the positive electrode material to lose its activity and generate a lot of heat; ordinary electrolytes will decompose when the voltage is higher than 4.5V.
In order to solve these problems, people try to develop a new battery system that can work under very harsh conditions. On the other hand, the current commercial lithium-ion battery must be connected to a management system so that the lithium-ion battery can be effectively controlled and managed. Each single battery works under proper conditions, which fully guarantees the safety, durability and power of the battery.(Lithium - Ion Battery Equipment)
Meaning of battery management system
The important task of the battery management system is to ensure the design performance of the battery system, which can be broken down into the following three aspects:
1) Safety, protect battery cells or battery packs from damage and prevent safety accidents;
2) Durability, so that the battery works in a reliable safe area and prolongs the service life of the battery;
3) Power performance, to maintain the battery working in a state that meets the requirements of the vehicle.
BMS is composed of various sensors, actuators, controllers, and signal lines. In order to meet relevant standards or specifications, BMS should have the following functions.
1) Battery parameter detection. Including total voltage, total current, single battery voltage detection (to prevent overcharge, overdischarge and even reverse polarity), temperature detection (it is best to have a temperature sensor for each string of batteries, key cable connectors, etc.), smoke detection (to monitor electrolysis liquid leakage, etc.), insulation detection (monitoring leakage), collision detection, etc.
2) Battery state estimation. Including state of charge (SOC) or depth of discharge (DOD), state of health (SOH), state of function (SOF), state of energy (SOE), failure and safety state (SOS), etc.
3) Online fault diagnosis. Including fault detection, fault type judgment, fault location, fault information output, etc. Fault detection refers to the use of diagnostic algorithms to diagnose fault types based on collected sensor signals and to provide early warning. Battery failures refer to sensor failures and actuator failures (such as contactors, fans, pumps, heaters, etc.) wait. The failure of the battery pack itself refers to overvoltage (overcharge), undervoltage (overdischarge), overcurrent, ultra-high temperature, internal short circuit fault, loose joint, electrolyte leakage, insulation reduction, etc.
4) Battery safety control and alarm. Including thermal system control, high voltage safety control. After the BMS diagnoses a fault, it notifies the vehicle controller through the network and requires the vehicle controller to deal with it effectively (the BMS can also cut off the main circuit power supply when a certain threshold is exceeded) to prevent high temperature, low temperature, overcharge, overdischarge, and overheating. Damage to the battery and personal life such as current flow and leakage.
5) Charge control. There is a charging management module in the BMS, which can control the charger to charge the battery safely according to the characteristics of the battery, the temperature and the power level of the charger.
6) Battery balancing. The existence of inconsistency makes the capacity of the battery pack smaller than the capacity of the smallest cell in the pack. Battery equalization is to use active or passive, dissipative or non-dissipative equalization methods based on the information of single cells to make the capacity of the battery pack as close as possible to the capacity of the smallest single cell.
7) Thermal management. According to the temperature distribution information in the battery pack and the charging and discharging requirements, the intensity of active heating/radiation is determined
When the temperature is too high, it will adversely affect the life of the battery. When the temperature is high to a certain level, it may cause safety problems, which will cause lithium metal to form an electroplating layer on the surface of the negative electrode, which will reduce the cycle life of the battery.
Too low voltage or over-discharge will cause the electrolyte to decompose and produce flammable gas, which will lead to potential safety risks. Excessive voltage or overcharge may cause the positive electrode material to lose its activity and generate a lot of heat; ordinary electrolytes will decompose when the voltage is higher than 4.5V.
In order to solve these problems, people try to develop a new battery system that can work under very harsh conditions. On the other hand, the current commercial lithium-ion battery must be connected to a management system so that the lithium-ion battery can be effectively controlled and managed. Each single battery works under proper conditions, which fully guarantees the safety, durability and power of the battery.(Lithium - Ion Battery Equipment)
Meaning of battery management system
The important task of the battery management system is to ensure the design performance of the battery system, which can be broken down into the following three aspects:
1) Safety, protect battery cells or battery packs from damage and prevent safety accidents;
2) Durability, so that the battery works in a reliable safe area and prolongs the service life of the battery;
3) Power performance, to maintain the battery working in a state that meets the requirements of the vehicle.
BMS is composed of various sensors, actuators, controllers, and signal lines. In order to meet relevant standards or specifications, BMS should have the following functions.
1) Battery parameter detection. Including total voltage, total current, single battery voltage detection (to prevent overcharge, overdischarge and even reverse polarity), temperature detection (it is best to have a temperature sensor for each string of batteries, key cable connectors, etc.), smoke detection (to monitor electrolysis liquid leakage, etc.), insulation detection (monitoring leakage), collision detection, etc.
2) Battery state estimation. Including state of charge (SOC) or depth of discharge (DOD), state of health (SOH), state of function (SOF), state of energy (SOE), failure and safety state (SOS), etc.
3) Online fault diagnosis. Including fault detection, fault type judgment, fault location, fault information output, etc. Fault detection refers to the use of diagnostic algorithms to diagnose fault types based on collected sensor signals and to provide early warning. Battery failures refer to sensor failures and actuator failures (such as contactors, fans, pumps, heaters, etc.) wait. The failure of the battery pack itself refers to overvoltage (overcharge), undervoltage (overdischarge), overcurrent, ultra-high temperature, internal short circuit fault, loose joint, electrolyte leakage, insulation reduction, etc.
4) Battery safety control and alarm. Including thermal system control, high voltage safety control. After the BMS diagnoses a fault, it notifies the vehicle controller through the network and requires the vehicle controller to deal with it effectively (the BMS can also cut off the main circuit power supply when a certain threshold is exceeded) to prevent high temperature, low temperature, overcharge, overdischarge, and overheating. Damage to the battery and personal life such as current flow and leakage.
5) Charge control. There is a charging management module in the BMS, which can control the charger to charge the battery safely according to the characteristics of the battery, the temperature and the power level of the charger.
6) Battery balancing. The existence of inconsistency makes the capacity of the battery pack smaller than the capacity of the smallest cell in the pack. Battery equalization is to use active or passive, dissipative or non-dissipative equalization methods based on the information of single cells to make the capacity of the battery pack as close as possible to the capacity of the smallest single cell.
7) Thermal management. According to the temperature distribution information in the battery pack and the charging and discharging requirements, the intensity of active heating/radiation is determined
