The Large Capacity Lithium Battery Into Test System Hardware Design And Implementation

With the world’s growing shortage of non-renewable energy and rapiddevelopment of mobile electronic devices, those Li-ion batteries with higher power ratioand energy ratio have been widely used. Battery formation in battery manufacturingprocess as key processes related to the quality of battery and it is a direct impact onproduction costs. So formation and test system play an important role in Li-ion batteriesindustry. At present formation and test device in our country has to be improved in thefunction, such as the device’s stability, accuracy, power consumption need to improve.Detection parameters is not comprehensive enough, what’s more its price is relativelyhigher. Due to the problem of the battery formation equipment’s design and itsefficiency caused a lot of energy wasted, especially during large-capacity batteryformation process. So we urgently need a new type of testing equipment to meetdomestic demand. According to the need of market, a new type of high-capacity Li-Ionbattery formation and test system is designed and developed.According to design demand, the system adopts a distributed three-tier distributedcontrol structure: the host computer, upper computer and lower computer of three parts,namely the PC, ARM, STM32controller and the underlying controller. The PC realizeremote control with Ethernet, while the crew as site controller transmit command to thebottom and receive tested data with CAN communication. The system have achievedformation centralized control management to single lithium-ion battery and test therelevant parameters of battery, such as its current, voltage, temperature and other dataalso can be tested, then detecting whether the battery is qualified and separate thebattery. The system combined information and test function, which can easilycentralized control and management. This dissertation mainly recounts the hardwaredesign of a Li-Ion battery testing system. It emphasizes the characteristics of charge anddischarge circuit design and testing of the subsystem design, then competed testing ofthe system.There are two discharge and charge modules which are chosen tocharge-discharge to the battery. TL494as PWM controller achieve the control of half-bridge DC\DC converter. The regulation of pulse width can realize charge anddischarge to battery by the mode of constant current or constant voltage. According tothe feedback values of current and voltage, using closed-loop control can achieveprecise charge-discharge to battery. In order to improve the energy efficiency, during theprocess of formation, energy released can be transfer to other battery and its energy alsocan be transfer to grid by DC bus. The cost of equipment can greatly reduced by energyefficient design. The overall system has security design, equipped with over-current andover-voltage protection, monitoring ambient temperature. The device ambienttemperature can be detected by temperature sensor DS18b20. Because of Li-ion internalstructure and electrochemical property, its resistance measurement is a little difficult.After studying domestic and international current situation, the resistance is measuredaccurately by the method of AC injection. The whole system is tested after eachhardware module is design. The system has been proved high stability, high precision,high security, and easy to operate equipment.