BMS

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. ...

Most battery simulation work happens inside large OEM simulation frameworks - tools with hundreds of subsystems, long setup times, and infrastructure built for full-vehicle analysis. Useful when you need the full vehicle. Counterproductive when you need to iterate quickly on battery-specific questions. At Volvo Trucks, the problem was clear: the battery and BMS teams needed a simulation environment they could actually use - fast iteration, battery-focused, not dragging a full vehicle model along for every run. ...

The EV marketing spec says “0 to 80% in 22 minutes.” It rarely says how long 80 to 100% takes. The omission is deliberate - and it reveals something fundamental about how lithium-ion cells actually work. The CC-CV Profile and Why the Transition Matters Lithium-ion charging follows a two-phase profile, not because someone decided it was a good idea, but because cell physics demands it. Constant Current (CC) phase: You push current in at a fixed rate. The cell voltage rises as SoC increases. This phase is efficient - you’re putting energy into the cell at the maximum rate the chemistry allows without exceeding the voltage limit or driving electrochemical side reactions. ...

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. ...