1 Why do lithium batteries need protectionLithium-ion batteries are most afraid of over-charging and over-discharging in use. Voltage characteristics of batteries in different materials Lithium iron phosphate(LiFePO) series: Factory standard charging cut-off voltage ≤3.85V, discharge cut-off voltage ≥2.5V Nickel, Cobalt, Maganese(NCM) series: Cut-off voltage ≤4.2V, discharge cut-off voltage ≥2.7V Lithium manganate(LM. 1 Why do lithium batteries need protectionLithium-ion batteries are most afraid of over-charging and over-discharging in use. Voltage characteristics of batteries in different materials Lithium iron phosphate(LiFePO) series: Factory standard charging cut-off voltage ≤3.85V, discharge cut-off voltage ≥2.5V Nickel, Cobalt, Maganese(NCM) series: Cut-off voltage ≤4.2V, discharge cut-off voltage ≥2.7V Lithium manganate(LMO) series:Cut-off voltage ≤4.2V, discharge cut-off voltage ≥2.7V Term: Over-charge:The charging voltage exceeds the upp. 2 Lithium battery protection product classificationIn order to meet different needs, there are many types of lithium battery protection products.1 Characteristics and classification of the hardware-type protection boardHardware-type protection board: Use special lithium battery protection chip, when the battery voltage reaches the upper limit or lower limit, the control switch device MOS tube cut off the charging circuit or discharging circuit, to achieve the purpose of protecting the battery pack. Characteristics: 1. Only over-charge and over-discharge protection can be realized. Partial can realize over current protection, short circuit protection, over temperature protection, and reverse connection prote. 2 Hardware-type protection board physical appearanceBelow is the physical appearance of the Hardware-type protection board：3 Separate port Hardware-type protection boardCharging and discharging circuit is different, i.e., charging and discharging port are separated.4 Common port(Same port) Hardware-type protection board2 Software-type protection board System schematicBelow is system schematic of software-type protection board:3 Characteristics and classification of the software-type protection boardIn addition to the basic functions of the hardware-type protection board such as over-charge, over-discharge, over-current, over-temperature, short circuit, etc., it also has the following functions: Communication functions: CAN/RS485/RS232/UART/I2C/SMBus/ModBus, Bluetooth, WIFI, GPS+GPRS, 4G Battery condition estimation(SOC/SOH) Warning function Online fault diagnosis function Data storage and record function Display function Balancing function Charge and discharge management Thermal managem. 4 The difference between MOS tube and relayMOS tube: Advantage: Voltage driven, electronic switch, no touch spot, small size, fast switching speed, high working frequency, no electromagnetic interference, equipped direction, quiet action Disadvantage: Severely emit heat, with high temperature derating characteristics, the higher the temperature, th. 1 Introduction to the Battery Management SystemBMS is the abbreviation of Battery Management System, commonly known as battery nanny or battery housekeeper. It is an electronic device that can monitor and manage the battery. It can control the charging and discharging process of the battery by collecting and calculating the voltage, current, temperature and SOC of the storage, so as to realize the protection of the battery and improve the comprehensive performance of the battery.2 BMS system architecture1. Master-slave Architecture(Centralized): It has the advantages of low cost, compact structure, and high reliability. It is commonly used in scenarios where the capacity is low, the total voltage is low, and the battery system volume is small. Such as power tools, intelligent robots (handling robots, assist robots), IOT smart home (sweeping robots, electric vacuum cleaners), electric forklift, electric low-speed vehicles (electric bicycles, electric motorcycles, electric sightseeing vehicles. 3 BMS electric system diagram.
