Continental Introduces New Sensor to Protect EV Batteries

Battery Crash Detection - Intelligent Baseplate Protection

Typically, an electric vehicle's lithium-ion battery is integrated into the vehicle's floorboard position, lowering the vehicle's center of gravity and giving it protection from the vehicle structure - but there are two potential anomalies: at high speeds, items such as straps can roll up and damage the floorboard. Damage could also be caused to the battery floor plate when the car touches the ground at low speeds during parking. For this reason, electric cars are often equipped with a large and heavy cover that protects the battery box from the bottom. However, if a crash occurs, the driver has to judge whether the car should be taken to a garage for inspection. Johannes Clemm, Managing Director of Safety Engineering at Continental in Alzenau, says: “This situation is not very satisfactory because visibility under the car is poor, and also because only an experienced driver can assess the true extent of the damage under the car.” To solve this problem and create a viable lightweight underbody protection system, Continental developed a pressure sensor-based battery crash detection solution.

This system is able to detect and differentiate between car underbody impact events in order to alert the driver when the battery is damaged. This allows the vehicle owner to take preventive measures before a damaged battery catches fire, Clemm added: “In addition, the BID is able to identify the damaged area to tell the battery management system to de-energize the battery in that area, thus preventing a fire from occurring.”

The BID responds to two typical crash risks: one is low-speed ground contact, such as when a car slowly rolls over a curb and hits the ground while parked. In this type of situation, the BID signal can trigger the active suspension system to temporarily increase floorboard clearance to mitigate damage. Another use case is high-speed intrusion, which is caused by heavy objects such as rocks or straps rolling up from the road. At certain speeds and impacts, such objects can damage the base plate and may even poke through the battery structure.

Sensor-based underbody protection saves up to 50 percent of the weight of current battery protection solutions compared to existing solutions. the pressure sensor satellites used in the BID originate from the proven Pedestrian Protection System (PPS pSAT), which has been mass-produced and used in millions of vehicles for more than a decade. the BID is designed to protect against the impact of a heavy object, such as a rock or strap-on, on the road surface. Any impact is detected by a pressure signal from an inflatable silicone tube that is integrated in an S-shaped drive belt at the bottom of the battery box. The time difference between the signal reaching the two pressure satellites at each end of the tube helps to calculate the impact area. The severity of the impact can be differentiated by a signal threshold, which triggers a cascading alert to the driver.