The Tesla Roadster scales laptop cells into an electric-car pack

The original Tesla Roadster did not rely on one giant cell. Its pack combined thousands of cylindrical lithium-ion cells similar in format to those used in laptops, organised into modules and supervised by a battery-management system. Sensors, electronics and liquid cooling kept cell temperatures and charge levels within controlled limits, while isolation measures reduced the chance that one failed cell would affect the entire pack. The approach showed that mature consumer-cell manufacturing could be scaled into a vehicle with roughly 200 miles of rated range and rapid acceleration. It also demonstrated that the battery pack is an engineered system, not a box of cells: performance, lifespan and safety depend heavily on software, cooling, packaging and power electronics.