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Why fiber optics sensors are the best temperature sensors to use in EV Battery Abuse testing?

posted by Rugged Monitoring on 2021-09-01

What is EV Battery Abuse Testing? Why is it important when designing an EV Battery?

Lithium-ion batteries are a proven technology that is used in the E-Mobility industry and its usage in the creation of a high-performance electric vehicle fleet in undeniable. So, ensuring the safety of these EV batteries are paramount in building confidence and encouraging customers to switch to electric vehicles. To achieve this, the batteries that are being developed must be tested in terms of its performance, durability, and mainly their tolerance of extreme EV conditions. An EV Battery’s ability to withstand harsh ambient conditions without its performance or longevity being affected is the goal of EV Battery Abuse testing. There are several types of battery abuse testing that occur before it is implemented into the EV. These include electrical, thermal, mechanical abuse testing.

Why is thermal monitoring required during EV Battery abuse testing?

Thermal monitoring is crucial at battery abuse testing as it informs that engineers in which materials have a higher abuse tolerance and a higher overall energy storage system safety. Also, temperature monitoring during abuse testing allows for a detailed analysis of the shortcomings and limitations of the battery. The thermal profiling of crucial components within the battery during abuse testing is imperative as the monitoring system will detect which parts of the battery will be compromised. Furthermore, these monitoring systems help the EV battery design and regulatory engineers because it helps detect vulnerabilities within their product before it gets implemented into EVs which eliminates the chance of a recall and loss of money for the battery manufacturing company.  

Why fiber optics sensors are better than thermocouples in thermal monitoring of EV Battery Abuse testing?

Fiber optics sensors provide fast, accurate readings which reliable and have a repeatability rate of 100%. On the other hand, traditional sensors such as thermocouples have low rates of repeatability especially when they exposed to high electromagnetic frequencies. Thermocouples can also be compromised at high voltages which leads them to produce inaccurate, slow, and unreliable readings. 

Furthermore, thermocouples are made from metal which is an issue because when EV prototypes are being tested at high voltages, metals have a high risk of creating a short-circuit which is hazardous for the researchers, the prototype and the testing environment. Alternatively, fiber optics sensors provide safety to the testing faculties and its researchers as it has a GaAs (non-metal) crystal which shows precise readings while being ultra-small. This allows it to reach tight spaces within the battery to detect the presence of any hotspots or identify if there is any thermal runaway happening within the battery. 

Additionally, Fiber optics sensors have numerous benefits over traditional sensors such as -  

  • The CANBUS is implemented to communication with dataloggers or car Battery Management System
  • Easy to reuse sensors and monitors; do not require recalibration or complex inputs to operate
  • Rugged sensor tip (vibration withstand capability of 8g) is suitable for all test conditions
  • Faster response time of 0.1s to 1 ms helps in identifying sudden temperature increase within cells
  • Higher immunity to electromagnetic interferences increases the testing accuracy and repeatability

Rugged Monitoring Thermal Profiling Sensors

Rugged Monitoring’s Fiber Optic battery temperature sensors are being used by battery design/test engineers at each stage for battery performance testing

  • Battery cell core and anode thermal profiling for fast charging
  • Intercell temperature monitoring in Battery Modules
  • Battery pack abuse testing and HV connectors temperature testing

The CANBUS is implemented to communication with Battery Management System or dataloggers. Also, RM sensors and monitors are easy to use as they don’t require calibration or complex inputs along with being rugged and suitable for all test conditions. Also, RM sensors have a higher immunity to electromagnetic interferences which increases the testing accuracy and reliability while being having a very fast response time of 0.1ms to 1ms that helps identify a sudden shift in the temperature within the cells. The state-of-the-art sensors of RM such as  LSENS-B, LSENS-T, LSENS-R are most reliable option that provides accurate, fast results while being easy to setup and use. The EV test rigs come with built in Fiber Optic temperature monitors , R501, O201 etc.