Design Ideas of Lithium Iron Phosphate Battery Pack Management System

Lithium iron phosphate battery management system design In order to ensure the safety and reliability of lithium iron phosphate batteries, a coordinated management system for battery packs must be developed and manufactured. The battery management system provides interfaces for interaction with external systems (such as charging power supplies, switching devices, loads, and data display devices). A battery management system turns a pile of dumb batteries into smart batteries. The rapid development of electric vehicles in automobile manufacturers and related manufacturers benefited from the higher performance and better functions provided by the battery management system. The management system can be divided into two categories: battery monitoring and battery control; the monitoring part includes voltage and temperature measurement and battery balance. These are the basic attributes of a battery management system. Although the lithium iron phosphate battery is still safe under short circuit, overcharge, squeeze, needle stick, etc., it will greatly affect the cycle life of the battery. The processing technology of lithium iron phosphate battery is complicated. The consistency difference of the single battery is greater than that of the sealed valve-regulated lead-acid battery, which can make the voltage of the single battery rise rapidly in the later stage of the personal battery pack charging, and the difference will seriously affect the service life of the battery. In order to prevent the above phenomenon, a power management system is required to ensure The battery is safe and reliable. The battery management system (battery management system, or BMS) and the battery pack are the core parts of protection and management, which not only ensure the safe and reliable use of the battery. It can also give full play to the performance of the battery and extend the service life. As a backup power source, the communication between the high-voltage DC power supply and the battery management system serves as a bridge. The battery management system must meet the requirements of the communication power system, so the safety management mode of the battery management system is very important to the safety of the battery. The battery management system mainly includes a data acquisition unit, a calculation and control unit, a balance unit, a control execution unit and a communication unit. The schematic diagram of the architecture is as follows: Design of lithium iron phosphate battery management system 1. Basic functions of the battery management system (1) Monitor the working status of the single battery, such as detecting the voltage of the single battery, charging and discharging current, and the ambient temperature of the battery pack; 2) Protect the battery to prevent shortened battery life and battery damage under extreme conditions. 2. Important functions of the battery management system (1) Over-voltage protection When the charging voltage of a single battery exceeds the allowable value, immediately stop charging and disconnect the charging device from the battery pack: (2) Over-discharge alarm when the single battery is discharged When the voltage is lower than the warning value, an alarm signal is issued. (3) Over-discharge protection When the discharge voltage of the single battery is lower than the protection value, the discharge is stopped immediately, and the electrical equipment is disconnected from the battery pack, accompanied by an alarm; (4) The over-current alarm is when the battery is input or output When the current exceeds the warning value, an alarm will be issued. (5) Short-circuit protection When the battery is short-circuited, it immediately stops discharging, disconnects the electrical equipment from the battery, and gives an alarm; (6) Over-temperature alarm When the battery temperature or ambient temperature exceeds the warning value, an alarm: (7) ) High temperature alarm When the battery temperature or ambient temperature exceeds the warning value, an alarm is issued. (8) Over-temperature protection When the ambient temperature or the internal temperature of the battery exceeds the protection value, immediately disconnect the charging or the connection between the electrical appliance and the battery pack, accompanied by an alarm. When the ambient temperature or the internal temperature of the battery returns to the allowable value, the battery management function can be restored manually or automatically without affecting the battery discharge function. 3. Estimate the battery SOC state of charge, that is, the remaining battery power. Keep the SOC within a reasonable range, prevent the battery from being damaged due to overcharge or overdischarge, and predict the remaining capacity of the battery at any time; 4. Balanced single battery Because the manufacturing process of lithium iron phosphate battery is complicated, the lithium ion is relatively active, so there is a single battery in the battery pack. The battery voltage is not consistent. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the charging methods for lithium batteries?