Sensor solutions for e-mobility

The expansion of cell thickness caused by charging can typically be reversed during discharge. However, under certain conditions, such as low temperatures or high charging currents, this reversal may not be fully effective due to a phenomenon known as lithium plating. This occurrence not only reduces the lifespan of the battery cells but also elevates safety risks.

To accurately measure the forces acting on the battery during these processes, specialized force transducers are employed. These devices are designed to maintain precision even under challenging environmental conditions. Moreover, they are capable of detecting even the smallest changes in force with high reliability, ensuring accurate measurements throughout extended test durations.

The lithium-ion battery serves as the central power source for electric vehicles, but its positioning differs significantly from the fuel tank in conventional cars. Typically housed beneath the passenger compartment for added protection, the battery is particularly vulnerable during collisions.

When subjected to external forces during a crash, a charged battery can experience a short circuit. This may trigger a chemical reaction that, in the presence of oxygen, can ignite and lead to a fire. To mitigate these risks, batteries are designed with reinforced housing and placed in carefully selected locations within the vehicle.

Comprehensive testing ensures battery safety under collision scenarios. Specialized test benches measure parameters such as distance, power, voltage, and temperature, while full-scale crash tests are conducted in dedicated facilities. For example, Mercedes-Benz performs approximately 900 such tests annually (Autosport, Luca Leicht, March 19, 2022).

Crash tests play a crucial role in evaluating the risks associated with vehicle accidents. While computer simulations provide valuable insights, real-world crash tests remain indispensable. These tests involve specialized force sensors placed both in the vehicle and in crash test dummies, which are meticulously designed to replicate various occupant types.

Modern crash test dummies are equipped with up to 220 measurement points, enabling detailed analysis of biomechanical loads experienced by occupants during a collision. Data collected from these physical tests is compared with computer simulation results to validate their accuracy and reliability.

The outcomes of these tests offer critical insights into occupant protection, vehicle structural weaknesses, and the performance of advanced safety and assistance systems. This comprehensive approach ensures that vehicles meet stringent safety standards before they reach the roads.

In the latest generation of Advanced Driver Assistance Systems (ADAS) and autonomous vehicles, highly accurate IMUs are indispensable. They enable precise prediction of a vehicle’s movement and determine its exact position in real time. To further enhance accuracy, IMU data is often integrated with inputs from GPS receivers and image-based sensors, such as lidar and cameras. This combined information allows for continuous and reliable estimation of the vehicle's position, ensuring safe and effective navigation.

Pedal force transducers are essential tools for measuring the forces required to operate the brake, accelerator, and clutch pedals. These measurements provide critical insights into ergonomic factors and the interplay of various muscles involved in generating force. By analyzing these dynamics, manufacturers can optimize pedal design for enhanced user comfort and performance.

Similarly, 3-axis force sensors are used to assess gear lever operation, allowing for early evaluation of shift quality. These sensors provide precise measurements by outputting the force components along three axes as separate signals. Delivered fully calibrated, these force transducers are ready for immediate use in testing environments.

For safety belt testing, specialized force transducers are employed to perform accurate force measurements. Characterized by their low weight and high strength, these sensors are ideal for dynamic applications, such as crash tests, where distortion-free measurements are critical. Their robust design ensures reliable performance under extreme conditions, providing valuable data for the development of safer vehicles.