High Precision Charger
The Novonix High Precision Charger (HPC) is the state-of-the-art system for non-destructively diagnosing the degradation mechanism of Li-ion cells and predicting the lifetime of the cells. The system can measure the coulombic efficiency (ratio of discharge to charge capacity) of a Li-ion battery more accurately than any commercially available chargers. The HPC was originally built by Prof. Jeff Dahn’s group at the Dalhousie University in Canada and has a wide variety of applications in battery design, reliability testing, and life-cycle analysis.
The HPC system in the SRSL is currently being used to support multiple research projects related to the reliability and safety of Li-ion batteries and is part of the Advanced Battery Failure Diagnostics research capacity that is being developed at the SRSL. Examples of these projects are listed as follows:
- Long-term performance prediction of new battery chemistries and designs through short-term measurement of coulombic efficiency, which allows lifetime estimates to be made in a short term (e.g., a few weeks);
- Differential voltage (dV/dQ) and differential capacity (dQ/dV) analyses for identification of degradation mechanisms and prediction of lifetime, and the integration of these analyses with Battery Management Systems (BMSs) for improving the operational reliability and safety of Li-ion cells under varying operating conditions;
Non-intrusive detection of critical failure modes such as the onset of lithium plating, which allows the identification of voltage and current thresholds of when lithium plating occurs for a specific cell design, and the optimization of the charging rate at a given temperature without degrading the cell capacity.
Neware BTS4000 Battery Test System
The SRSL has recently purchased new battery test equipment, BTS4000, provided by Neware as part of a collaborative research project. The BTS4000 battery test system is based on Neware’s 4th generation testing system and is extensively used in both academia and industry. Test procedures can be programmed into a simple computer user interface, allowing for a variety of constant or variable current charge and discharge routines. In addition to standard charge/discharge testing, the BTS4000 can also perform electric vehicle (EV) pulse tests, hybrid pulse power characterization (HPPC) tests, and DC Internal Resistance tests.
The BTS4000 battery test system, when coupled with the HPC, creates the perfect combination for battery research. The BTS4000 greatly complements the HPC in life cycle testing and other long-term testing applications where high precision measurements are not needed. For example, the lifetime prediction of Li-ion cells by the HPC can be validated by performing full life-cycle testing on the cells with the BTS4000 System. With this new test equipment and a partnership with Neware, the SRSL will continue to develop advanced diagnostics and prognostics to determine degradation mechanisms and predict lifetime of Li-ion batteries.