Li Auto L9 and Livis Models Adopt Brake-by-Wire Tech, Sparking New Challenges in Aftermarket Fitment and High-Temperature Performance

Models such as the Li Auto L9 Livis and Chery’s Exeed EX7 have begun adopting fully x-by-wire digital chassis technology, which includes brake-by-wire systems. These systems eliminate traditional hydraulic lines, instead using electronic signals sent from the vehicle’s computer to directly drive pistons via electric motors for braking, thereby improving response speed and safety. Because brake-by-wire systems replace conventional hydraulic lines with electrical wiring, traditional aftermarket brake calipers are incompatible, posing installation challenges for modification shops that rely on legacy braking architectures. To ensure safety, China’s 2023 “Technical Requirements and Test Methods for Braking Systems of Passenger Cars” explicitly mandates that brake-by-wire systems must still support at least nine emergency braking events meeting regulatory standards even after a single-point communication failure. To comply with this requirement, automakers have implemented multi-layered redundancy designs. For instance, the Chery EX7 is equipped with three independent power sources: the main battery plus two small backup batteries located on the left and right sides of the trunk. Its communication lines also feature multiple redundant pathways to guarantee system functionality under extreme conditions. Despite these extensive safety redundancies, brake-by-wire systems still carry potential risks in high-performance driving scenarios. Under high temperatures, the permanent magnets in motor-driven calipers may experience demagnetization, which could compromise braking performance. Currently, both the Li Auto L9 Livis and Exeed EX7 are primarily targeted at everyday, moderate-use family applications, where this issue remains negligible. However, as the technology becomes more widespread, further optimization of high-temperature stability will be necessary.