Expected Outcomes
The Waikato Battery Team’s research project is good news for battery manufacturers, those who make and use battery management systems, and those who operate grid-level battery energy storage systems (BESS)s. It will make battery systems more profitable, electric vehicles more trusted, and implant surgeries less frequent. It can also prevent laptops going flat suddenly and cellphone batteries wearing out unexpectedly. Accurate measurement will optimize battery usage and minimize the environmental impact of battery waste.
The research project will result in:
- A low-cost battery cell measurement system that can make reliable and repeatable electrochemical impedance spectroscopy (EIS) measurements into the microhertz range (i.e., extra-low frequencies over very long timescales). This system would be invaluable to battery manufacturers, quality controllers and researchers in universities and industry.
- Technology to extract SoH from current and voltage measurements. This technology is efficient, needs very little memory, and could be implemented in a low-cost BMS with little or no modification to existing hardware.
- Technology to extract SoC in addition to SoH: particularly valuable for applications where fully charged and discharged states may not be reached for long periods of time and/or for battery chemistries (e.g. LiFePO4) in which voltage barely changes despite large changes in SoC. This technology will be more computationally intensive and is expected to be suitable for larger applications such as EVs and energy storage systems.
Batteries in medical equipment are replaced too early because the hospital team has no way to know its charge situation. The alert is posted based on estimates of the battery state of charge. The battery might have longer than thirty minutes of charge left, but we can’t be sure. The Waikato Battery Team develops new technology that would provide science-based accurate data on rechargeable batteries’ state of charge.