System for Forming and Testing Batteries in Parallel and in Series

A circuit assembly for forming and testing batteries connected in parallel and in series includes a parallel test management device (PTMD) that connects to each battery and includes a main relay and a current transducer in series and an auxiliary relay in series with a current limiting resistor, which are parallel to the main relay. Parallel battery groups are formed by connecting multiple PTMD-battery combinations and a voltage equalizer in parallel. Multiple parallel battery groups are connected in series. A high-current, high-density battery testing system (BTS) connects to a battery formation rack that uses a double-sided PCB and double-polarity edge connector sockets for receiving a battery tray on a PCB having an edge connector for forming and testing over 1,000 batteries. This smart battery tray replaces a bulky, complicated engagement system and reduces the requirement for BTS channels and cables substantially. An aging rack monitors battery voltage on the smart battery tray. The equalizers and BTS pass current through the batteries simultaneously. The current through batteries and the voltage drop across the current transducer are about zero at the end of charge and discharge. Battery capacity and coulombic efficiency are measured using CCCV charge and CCCV discharge rather than CCCV charge and CC discharge.