Electrochemistry

Most battery models fail not because the equations are wrong — but because the assumptions smuggled in with them are wrong. Fifteen years working with battery models across the stack: from ECM spreadsheets that needed to survive a BMS real-time loop, to full electrochemical models trying to capture what actually happens inside the cell during a fast charge. The gap between “runs on paper” and “works in a vehicle” is where most of the interesting problems live. ...

In battery development, the cell you’re simulating is rarely the cell you have test data for. A customer RFI comes in specifying a 60 Ah prismatic. Your characterisation data is for a 40 Ah cylindrical from the same chemistry family. The programme timeline doesn’t allow for a full test campaign on the new cell before the simulation deliverable is due. This is the normal situation — not the edge case. ...

A battery’s safe operating envelope is not a fixed number. It’s a surface — varying continuously with temperature, state of charge, state of health, and operating history. Getting it wrong in the conservative direction costs performance and range. Getting it wrong in the aggressive direction costs cell life, and at the extreme, safety. The Current Limits Generator was built to define that surface correctly — from physics, not from conservative blanket rules. ...