A new type of lithium battery management system design

Source: 2020 - 03 - 23 14:48 hits: time was designed and implemented a new battery conduction system (lithium battery management system 'management system, BMS) , it includes technology and computer testing, the implementation of dynamic monitoring the battery unit and battery operating circumstances, can accurately check the residual capacity of battery, battery charging and discharging the maintenance, the best operating conditions, reduced working capital, working life. A combination of some advanced technological achievements at home and abroad, this paper designs and realizes a new kind of lithium battery management system. Management structure, modular and distributed planning system, including secondary control structure, namely the local measurement module and the central processing module. In the meantime, the main function of the central processing module is communicate with PC through RS232 interface, and through the CAN bus network connection method and the local measurement modules. Local measurement module's main function is data acquisition ( Is mainly used for temperature, current and voltage data acquisition) , charge and discharge control, balance of power measurement, single battery and using CAN bus technology to communicate with the central processing module. 1. System hardware planning in this paper, the planning of battery processing system is mainly used in electric vehicles and part of the underwater equipment, so the system planning should be reasonable structure, advanced technology, strong scalability; High precision system parameters of technology. As a result, the battery management system planning should complete the following functions: 1) Real-time acquisition battery information, including single battery voltage, battery voltage, charge and discharge current, temperature parameters such as; 2) Remaining power measurement and display; 3) CAN provide data transmission interface, complete with CAN bus and PC communication; 4) Good human-computer interaction, the system safe and reliable, strong anti-jamming capability. 2. Local measurement module 2 hardware planning. 1 voltage acquisition module monomer voltage of the battery is the main basis of calculating the residual battery, the choice of the ways of charging and discharging, as well as the running condition assessment, so monitoring is the premise of the battery pack should have reasonable monomer battery terminal voltage measurement. But always larger quantity of batteries in the battery voltage is higher, the measuring accuracy is higher, so to achieve power measurement is difficult. The working principle of voltage monitoring plan is as follows: the first step, single-chip microcomputer control kn - multi-channel switch 1 and kn 2 ( N Numbers between 1 to 7) , the synchronous connection corresponding capacitance at the ends of the battery, startup capacitor charging, and achieve the purpose, capacitor voltage is the same as the battery voltage; The second step is to disconnect the kn - MCU control 1 and kn More than 2 way switch, shut off the switch K1 and K2, connect it to the MCU A/D module is measured. When measuring time, according to prevent the battery terminal voltage instability formed by considering the influence of the results, choose the method of average measurement module. The scheme can be easily used microprocessor inside the A/D unit, do not add A/D module, improve the efficiency of programming, save money. Usually in the actual circuit, can use the relay to complete analog switch. 2. 2 current acquisition module for measuring dynamic current charge and discharge process, this paper USES the LEM company ltsr25 - Np current sensor. The element is a closed loop multirange current sensor, according to compensate hall effect, using the unipolar voltage method. With high measurement precision, without insertion loss, good linear, current overload ability, etc. Below 25 ℃ measurement precision can reach & plusmn; 0. 2%. Rated current of 25 amps, the maximum measurable current of 80 amperes. Current sensor can be converted to charge and discharge current 0 ~ 5 v voltage signal, and then connect to the MCU A/D unit, measuring the charge and discharge current.