Battery Thermal Analysis: Five Reasons for Using Optical Technology

With the electrification of vehicles of all kinds, the demand for durability, safety and performance of batteries, fuel cells and other e-drive solutions is also growing. To satisfy such requirements, the thermal management of batteries, is a key focus for hybrids or full electric vehicles.

With many years of experience, HBK develops and offers the necessary solutions for thermal validation measurements, covered by electrical or optical components, or even hybrid systems.

Taking a closer look at temperature measurements in battery testing, we talk about analysing performance and durability of batteries, but also optimizing their design. How do extreme temperatures impact the battery’s performance and charging? How does temperature influence the lifetime and durability of batteries? When does heat become dangerous? What battery design is ideal to provide enough power without being too big, heavy, etc.? Such questions are important to consider when developing safe, efficient, and reliable electric vehicles.

1. Fast Thermal Response

The response time of optical temperature sensors, and, particularly that of Fiber Bragg Grating (FBG) based sensors, can be extremely short, as heat transfer to this small, low-mass sensor is almost immediate.

2. Immunity to EM and RF Interferences

Optical technology can easily be used for very specific application scenarios in harsh environments, such as high magnetic fields, intense radio frequencies etc. Where electrical sensors would simply fail or need advanced protection methods, optical measurements are still reliable, accurate and stable.

3. Sensors: Passive and Made of Dielectric Materials

Optical technology is very well-suited for stable measurements and operations, such as in high-voltage environments or potentially explosive atmospheres. Passivity, corrosion resistance and the dielectric characteristics of optical sensors are advantages that can make FBG/optical sensors the only or best possible solution for certain applications. As these sensors are electrically insulated, they avoid interference with any other operation during measurement, and can be left inside the battery after the test, saving valuable time and resources. Moreover, they do not require a so-called excitation signal for measuring, making intrinsically safe devices in explosive atmospheres.

4. Multipoint Measurements

FBG technology offers the capability of multiplexing, which provides multi-point measurements, namely temperature measurements. The number of measuring points, FBG wavelengths and the distances between sensors can be freely defined allowing the collection of temperatures and the mapping of gradients with the desired spatial resolution. For a higher measurement density, the number of sensors can be easily increased while the number of cables that need to exit the battery is kept to a minimum, limiting the interference on the element under test. FBG technology also significantly reduces the number of cables that need to exit the battery, limiting the interference on the element under test.

5. Flexible Switch to Hybrid Measurements

The HBK QuantumX MXFS operates as a single optical interrogator module but, at the same time, it is also an optical integration toolkit for the complete QuantumX DAQ platform – a flexible and precise measurement chain that can be easily set up by ‘Plug and Measure’, for example, with catman. QuantumX MXFS also operates in synchronization with other QuantumX modules, so all the different sensors needed – electrical and optical – can be easily combined in a hybrid setup.

Taking these five advantages and many more into account, optical technology is indisputably suitable for the thermal testing of electric drive solutions.

HBK provides optical measurement solutions consisting of the QuantumX MXFS BraggMETER and the newLight optical FBG sensor FS70FBG, customized for temperature measurements.