After the cell assembly process, each Li-ion battery goes through gradual charging, during which it forms a solid electrolyte interphase (SEI) layer, which is critical for its long-term functionality. If this process is not well controlled, the battery can lose up to 50% of its capacity. Therefore, test equipment must provide precise constant-current and constant-voltage charging and discharging to control the thickness of the SEI layer. This can bring down capacity losses to below 5%.

Figure 7-1 shows application schematic using the ADS93x8V8I. The ADS93x8V8I enables solution for 8-cell battery formation and testing applications, providing simultaneous, high-precision monitoring of all battery cells in real-time. With 8 dedicated voltage channels and 8 current channels, this 24-bit ADC enables comprehensive characterization of each cell during charge/discharge cycles at 125kSPS per channel. The integrated zero-drift programmable gain amplifiers deliver ±0.01% full-scale current measurement accuracy, critical for precise battery testing and quality control. The device no-cycle-latency architecture enable immediate fault detection and fast closed-loop control, essential for protecting cells against over-current, over-voltage, or thermal events during formation cycles. Multiple configurable input ranges accommodate various shunt resistor configurations and cell voltage levels, while the 140dB common-mode rejection ratio ensures accurate high-side current sensing. By integrating 8 instrumentation amplifiers, 8 difference amplifiers, and a 16-channel SAR ADC in a single 8mm x 8mm package, the ADS9308V8I significantly reduces BOM cost, simplifies PCB layout, and enables compact automated battery test equipment design.

Figure 7-1 Multichannel Battery Cell Testing using the ADS9308V8I