The global e-bike market exceeded 40 million units sold annually by 2025, with a substantial share consisting of lower-cost direct-to-consumer models sourced from Chinese manufacturers and sold through third-party online platforms. The battery and braking system defects in these products have generated a rapidly growing category of product liability claims, ranging from fire-related burns and property damage to severe orthopedic injuries from sudden brake failure at speed. The legal framework for these claims is standard product liability, but the practical obstacles to recovery, specifically identifying responsible parties and obtaining jurisdiction over them, require a different approach than a domestic product case.
Lithium Battery Thermal Runaway: The Most Serious Injury Profile
Lithium-ion battery fires in e-bikes and e-scooters produce some of the most catastrophic injuries in the product liability case mix: severe burns over large body surface areas, smoke inhalation injury, and fire-related deaths, many of which have occurred indoors when the battery was left charging unattended. The New York City Fire Department reported over 200 e-bike battery fire incidents in 2023 alone, and the pattern continues nationally.
Thermal runaway occurs when an individual battery cell overheats and triggers a chain reaction across adjacent cells, causing the battery pack to ignite. Common design or manufacturing defects that contribute to thermal runaway include: absence of or failure of the battery management system (BMS) to detect and interrupt overcharge; use of substandard lithium cells that do not meet the capacity specifications printed on the battery housing; inadequate thermal separation between cells within the pack; and absence of overtemperature cutoff protection.
In a battery fire case, retain a certified electrical engineer and a fire investigator experienced in lithium-ion battery failures. Preserve the battery pack and charger as evidence immediately: do not allow the fire department or the property owner to dispose of them. The BMS failure analysis requires physical inspection of the cells and the circuit board, and if the battery has been destroyed by the fire, the charger records (some chargers log charge cycles and peak temperatures) may be the only remaining technical evidence.
Brake System Failures at Speed
The second major injury category involves sudden braking system failure in e-bikes and scooters capable of speeds between 20 and 28 mph. Common defects include hydraulic brake fluid contamination at the factory, crimped or undersized brake cable housing that allows the cable to bind under load, disc brake rotors that were not machined to the specified tolerance and produce vibration-induced brake fade, and electronic brake-by-wire systems that lose signal continuity and default to an unintuitive failure mode.
Brake failures in this category typically manifest after a period of use rather than on first use, which raises a manufacturing versus design defect analysis. If the defect is a contaminated hydraulic line that degrades brake performance over time, it is a manufacturing defect. If the design specifies an undersized cable housing that is inherently prone to binding under the forces generated at the rated speed, it is a design defect and affects the entire product line. The distinction matters for the scope of the defendant class and for the availability of punitive damages.
The Multi-Tier Supply Chain Problem
Most lower-cost e-bikes and scooters sold in the United States are manufactured in China by companies that have limited or no U.S. presence. The product typically moves through: a Chinese manufacturer or OEM assembler; a Hong Kong or U.S.-based import entity that holds the brand name; an online platform (Amazon, Walmart Marketplace, Alibaba-affiliated) that facilitated the sale; and in some cases a domestic retailer or rental operator. Depending on the state, each tier may be a proper defendant.
California, New York, and Illinois have statutes or established case law treating online marketplace facilitators as sellers in the product liability chain when they substantially participated in the sale. The California Supreme Court's 2021 decision in Bolger v. Amazon.com, LLC held Amazon strictly liable as a distributor for defective products sold by third-party sellers on its platform. That ruling remains the leading authority for platform liability in e-bike and similar direct-to-consumer product cases.
For the Chinese manufacturer or OEM, service of process under the Hague Convention on Service Abroad is the required mechanism for parties in China. The process is slow (six months to a year for service to complete and acknowledgment to return) and in many cases the manufacturer will default rather than appear. A default judgment against a Chinese manufacturer may have limited collectability unless the manufacturer has U.S. assets or bank relationships. The practical recovery path in most e-bike defect cases runs through the U.S.-based import entity, the platform, or the domestic retailer.
UL Certification and Standards as Evidence
UL 2849 is the voluntary safety standard for the electrical systems of e-bikes, and UL 2272 covers personal e-mobility devices including scooters. Products certified under these standards have been tested for battery safety, electrical fault protection, and mechanical integrity. Products that lack UL certification but carry counterfeit UL marks (a documented problem in the e-bike category) present a fraud-on-the-consumer theory in addition to the product liability claim.
If the subject product bore a UL or CE certification mark, request the certification documentation from the manufacturer or importer. Compare the model number on the certification to the model number on the product. If they do not match, the product was not actually tested and the certification was falsely applied. That is evidence of intentional misrepresentation and supports punitive damages against any party in the distribution chain who knew the mark was counterfeit. For coverage on product liability chain-of-distribution cases and punitive damages theory, see the product liability practice section. Battery fire injury damages and catastrophic burn cases are addressed in the wrongful death and catastrophic injury section.