Rising Unauthorized EV Battery Modifications Pose Serious Risks

Recently, a large number of accounts have emerged on short-video platforms promoting unauthorized battery modification services for new energy vehicles (NEVs) under the guise of technical sharing. These accounts offer two installation options—trunk-mounted and cargo-bed-mounted—with modified battery packs priced between RMB 500 and RMB 800 per kilowatt-hour (kWh). Adding a 20-kWh battery pack costs approximately RMB 15,000 in total, with claims of extending driving range by 160 kilometers. Full battery replacements are quoted at RMB 20,000 to RMB 30,000. As the first generation of NEVs gradually reaches the end of their 8-year or 120,000-kilometer warranty period for the "three electric systems" (battery, motor, and electronics), an estimated cumulative total of 41.6 million vehicles will be out of warranty over the next eight years. Assuming an average original-equipment battery replacement cost of RMB 60,000 per vehicle, the potential market size amounts to roughly RMB 2.5 trillion. However, such unauthorized modifications carry significant risks. Under current regulations, altering the power battery without authorization constitutes illegal vehicle modification. Added batteries typically lack the original manufacturer’s thermal management system; if installed in the trunk, they are prone to thermal runaway—and even spontaneous combustion—in rear-end collisions or electrical faults. Moreover, vehicle annual inspections now explicitly check for signs of modification, meaning illegally modified vehicles cannot pass inspection. In the event of an accident, insurers may deny claims on this basis, and the vehicle’s original warranty coverage (under China’s "three guarantees" policy) would also become void. The current chaos stems from dual challenges faced by vehicle owners and independent repair shops, with unmet demand and supply gaps fueling an illicit modification industry chain.