Aging

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. ...

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. ...

After spending years working in battery simulation across Mercedes-Benz, Caterpillar, Volvo Trucks and later A123 Systems, I slowly realised something that was not obvious to me in the beginning. Most battery engineers think they are building battery models. In reality, they are usually building battery infrastructure. The distinction sounds subtle. It isn’t. A battery model answers a question. A battery simulation framework enables an organisation to ask thousands of questions. Those are completely different engineering problems. ...

After spending years working in battery simulation across Mercedes-Benz, Caterpillar, Volvo Trucks and later A123 Systems, I slowly realised something that was not obvious to me in the beginning. Most battery engineers think they are building battery models. In reality, they are usually building battery infrastructure. The distinction sounds subtle. It isn’t. A battery model answers a question. A battery simulation framework enables an organisation to ask thousands of questions. Those are completely different engineering problems. ...