This reference design provides a cost-effective solution for battery formation and test applications. The design uses the C2000™ real-time control MCU for high-resolution pulse-width modulation (PWM) generation, and constant-current (CC) and constant-voltage (CV) control loops. It efficiently utilizes the MCU, and does not require a precision digital-to-analog converter, which saves more than 30% in the bill of materials. The flexibility of current and voltage loops in software allows users to achieve multiple current and voltage levels output with one design.

• Bidirectional current control up to 10 A with less than ±0.01% accuracy

• C2000 on-chip 12-bit ADC achieves control accuracy better than ±0.05%

• Parallel up to 8 channels for wide output current range

• Flexible digital constant-current and constant-voltage control loops

• Channel-to-channel crosstalk error below 0.01%

• Multilevel protection in hardware and software for reliable power supply design

• Battery test

The battery tester equipment includes a wide variety of battery formation and test equipment for single cells, battery modules, and high-voltage battery packs. The test equipment contains precision control circuits, data acquisition systems, and various manufacturing tools that are important quality control and battery research activities.

Figure 1-1 shows a simplified Li-Ion battery manufacturing process. Battery testing comes at final stages of the production, in which formation is the most critical process. After the cell assembly process, each Li-ion battery goes through gradual charging, during which it forms a solid electrolyte interphase (SEI) layer that can consume significant portions of total battery capacity. Therefore, the test equipment must be able to precisely control the thickness of the SEI layer, which can bring down the capacity loss during formation to below 5%.

Tests such as self-discharge measurement and life span estimation are performed to remove defective cells during production. The battery test equipment must possess accurate voltage and current control, often better than ±0.05%, over the specified temperature range.

Figure 1-1 Simplified Li-Ion Battery Manufacturing Process.