Continental Introduces New Sensor to Protect EV Batteries

May 30. 2022 , Technology company Continental has added to its extensive sensor portfolio with the introduction of two new sensors dedicated to electric vehicles - the Current Sensor Module (CSM) and the Battery Impact Detection (BID) system. These two new solutions focus on protecting the battery and/or maintaining battery parameters. Continental will begin manufacturing the new High Voltage Battery Sensor Module (CSM) during 2022. This compact modular sensor design measures current and detects temperature at the same time. Both values are closely related to battery management operations. Another innovative battery protection product introduced to the market by Continental is the Battery Impact Detection (BID) solution, which is a lightweight, breakage-resistant alternative to heavy-duty baseplate “armor”.

Laurent Fabre, Head of Continental's Passive Safety and Sensors Business Unit, said: “The electrification of the vehicle creates new use cases, and this opens up more opportunities for our sensors activities, as electric vehicles have all the same sensor needs as traditional vehicles, and even more. For example, protecting the battery and maintaining its performance are two tasks that need more attention in electric vehicles. The Battery Sensor Module and Battery Crash Detection Solution serve both purposes.”

Given that the battery is the most expensive component in an electric vehicle, the CSM has been developed not only to protect the battery from overload currents, but also to help maintain battery parameters by limiting the effects of aging.The CSM, which can be integrated in the pack disconnect unit or in the battery itself, will provide two decisive pieces of information to perform battery protection as well as reliable range monitoring. To meet stringent functional safety requirements, the CSM can be used as a dual-channel sensor, integrating shunt and Hall technology in a compact single unit to measure current independently.

The BID combines a lightweight structure that detects impacts from the ground and, if necessary, alerts the driver and heads for the repair shop. This eliminates the need for the driver to constantly and personally check for damage to the battery from impacts resulting from ground contact at high or low speeds. The BID solution saves up to 50% of weight compared to current metal chassis protection.

Reliable Charge Monitoring: Current Sensor Module Keeps Batteries Safe and “Healthy”

Lithium-ion batteries store a large amount of electrical energy and have a long life. These batteries can be subjected to high currents during charging. Due to unavoidable physical effects, charging (and discharging) causes the battery to heat up - especially during high-power rapid charging or in sports driving mode. To prevent overloading the car battery with current, the system must control the current to limit the temperature from rising too quickly.” Horst Gering, pre-strategy manager for the Passive Safety & Sensors Business Unit, said, “Lithium-ion batteries have an optimal temperature range in which they are very safe and age very slowly. However, fast charging is a balanced solution to keep the battery safe and 'healthy' and to control the charge duration. It is best to perform this operation with accurate data to support it.” The CSM is also able to help calculate a more accurate remaining charge by monitoring the consumption current.

The CSM measures current calibrated to 2000 amps with better than ±1% accuracy in the shunt channel, better than ±3% accuracy in the Hall channel, and a temperature measurement range of -40°c to 125°c. Both monitoring technologies currently support full current blocking. The sensors then provide this input to the battery management system via the CAN interface. In addition to optimizing charging efficiency and protecting the battery, the CSM will also help detect mechanical failures that could lead to misfire if not detected. the CSM is fully compliant with the system ASIL D. The CSM will be in volume production within 2022 in the advanced electric vehicle program of a global automaker. Its first product is part of a modular sensing platform that can be expanded for additional functionality such as voltage measurement and number of measurement channels.

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.