Battery Management System Measurements — Lesson 2

This lesson covers the essential aspects of Battery Management System (BMS) measurements. It delves into the importance of sensing voltage, current, temperature, and isolation in a battery pack. The lesson explains how these parameters are crucial for calculating the State of Charge (SOC) and State of Health (SOH) of a battery. It also discusses how these measurements are taken using integrated chips, current sensors, thermistors, and isolation monitoring devices. For instance, voltage is measured using an Analog to Digital Converter (ADC), which converts analog signals into digital values that a microcontroller can read. The lesson also provides practical examples and assignments to help learners understand these concepts better.

Video Highlights

00:19 - Concept of sensing in battery packs
06:21 - Use of analog to digital converter (ADC) in battery packs
09:33 - Explanation of how to relate ADC value to voltage
12:02 - How to sense thermistor value
15:10 - Example on how to measure thermistor temperature
14:50 - Sensing current values

Key Takeaways

- Voltage, current, temperature, and isolation are critical parameters in a Battery Management System.
- Voltage is essential for calculating the SOC and SOH of a battery pack.
- Current is used to detect any abnormal conditions in the battery pack.
- Temperature is crucial for predicting short-term and long-term cell performance.
- Isolation sensing enhances the safety of the battery pack.
- Analog to Digital Converter (ADC) is used to convert analog signals into digital values.
- The resolution of ADC is determined by its bit rating.
- Thermistors are used to measure temperature, and their resistance changes with temperature.
- Current can be sensed using a low resistance current path in series or a Hall Effect sensor.