SoH, SoC Estimation and Self Discharge - II — Lesson 8

This lesson covers the intricacies of measuring the State of Charge (SOC) and State of Health (SOH) in lithium-ion batteries. It explains the voltage method and the coulomb counting method for determining SOC. The lesson also highlights the importance of accurate SOH estimation and the role of Battery Management Systems (BMS) in maintaining battery health. It further discusses the impact of self-discharge on battery performance and the need for periodic recalibration. The lesson concludes with a discussion on the challenges of SOC and SOH estimation in real-world scenarios, such as electric vehicles.

Video Highlights

00:18 - Masuring the state of charge (SOC) and state of health (SOH) in batteries
01:36 - Coulomb counting method for SOC estimation
08:25 - Explanation of how to recalibrate the battery to correct for errors in SOC estimation
13:50 - Estimate the cycle/lifetime remaining in a battery
17:15 - How self-discharge affects the SOC of a battery

Key Takeaways

- The voltage method for determining SOC is applicable only when the battery is at rest or charging at a very slow rate.
- The coulomb counting method is more accurate but requires a correct starting point and depends on the precision of current measurement.
- Accurate estimation of SOH is crucial for maintaining battery health and performance.
- Self-discharge of batteries can impact their performance and should be considered in SOC and SOH estimation.
- Periodic recalibration is necessary to correct errors in SOC estimation.
- Battery Management Systems (BMS) play a vital role in maintaining battery health and ensuring accurate SOC and SOH estimation.