This page contains links to a whole bunch of relevant battery related resources necessary to understand and implement State of Charge (SoC) models.
Understanding Batteries
Battery Basics
Battery Safety
Battery 101 Zoom Meetings
Individual Cell Testing
Contains information on relevant parameters to test and why we test them - attempts to explain effects at a system level
Individual Cell Testing Evaluation
Single Cell Testing Data Processing
Explains some of the issues that occur with measurements and how to overcome them with data processing
Single Cell Testing - Data Processing Guide
Karl Ding’s SoC Estimation for MSXII - very good explanations
/wiki/spaces/~karlding/pages/620036100
Batteries & Strategy
There are 2 easy parameters in order to
State of Charge Models - Coulomb Counting
Measures the amount of energy going in and out of the battery pack, and makes an estimate on the amount of energy available. Requires a stream of data (current and time values) to measure the energy.
State of Charge Models - Open Circuit Voltage Correlation
The voltage of a battery decreases as energy is drained from it. By measuring the voltage, the state of charge can be estimated (but remember this is only at ‘open circuit’ - i.e. not when then car is drawing a large current from the motors). Requires only a single point of data under ideal conditions (voltage).
We have found that combining these 2 methods - the Coulomb Counting providing accurate energy usage during driving periods and the SoC OCV correcting for accumulated error in the current measurement to be fairly accurate.
Online Resources:
This is the most applicable to how we are currently thinking of pursuing this:
The rest of them in no particular order:
https://batteryuniversity.com/learn/article/how_to_measure_state_of_charge
Coursera Course - I haven’t taken it but it seems to look good: https://www.coursera.org/lecture/battery-state-of-charge/3-1-4-what-are-some-approaches-to-estimating-battery-cell-soc-TqN1d
Files from Micah Black
These are from my first crack at making a model for the strategy team - they worked but were not very expandable.