The Design Of Online Detector Of Rechargeable Batteries

In recent years, with the high-speed development of economy, the electronicproducts have filled with every corner of life, to a great extent, these productsimprove the quality of people’s lives and work efficiency. Energy storagerechargeable batteries have been widely used in real life and work as powersupply of electronic equipment, so people gradually pay attention to theirssecurity. And testing for the energy storage rechargeable batteries has become ahot research direction in the field of testing.This topic mainly doing performance testing for lead-acid batteries, due tothe parameters of the batteries are more, according to the working principle andelectrochemical properties of lead-acid batteries, so we select internal resistanceand voltage of batteries as the target parameters. This subject adopts "fourterminal measurement method", the method adopts the self-designed constantcurrent source to inject stable sinusoidal alternating into lead-acid battery, andthen battery produces corresponding feedback current. The phase differencebetween feedback current and sine signal of constant current source can be usedto make the subsequent processing, finally getting the measurement of internalresistance of battery, this method can effectively remove battery’s own voltageand external noise interference.Because the feedback signal amplitude of battery after injecting constantcurrent source is small, it is in the millivolt level, so separating the design ofanalog and digital circuit can effectively reduce the power frequency interference.This subject adopts modular design, detection terminal can be divided into:constant current source module, signal processing module, keyboard and displaymodule, communication module, power supply module, E2PROM and UARTmodule. The signal processing module is mainly making the analog circuit design,including power amplification circuit, sampling amplification circuit, band-pass filter circuit, voltage detection circuit. Voltage detection circuit is used to realizethe battery voltage measurement, since the voltage detection technology in thecurrent battery testing equipment is already mature, so this article has usedBQ26500chip as the core voltage detection circuit design. Detection terminal hasa built-in E2PROM, it can be stored internally on the measurement results, at thesame time with Ethernet interface in the communication module, themeasurement data can be real-time uploaded for storage to upper machine. Theupper machine has a graphical interactive operating software and database, whichcan effectively complete the mass data storage work. It shows that therechargeable battery online testing instrument has the characteristics of highaccuracy, stability, noise resistance and real-time through the actual workenvironment test, which can effectively finish detection work of lead-acid batteryinternal resistance and voltage.