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Thermal imagers and electrical car battery storage

The trend of electric-powered vehicles is creating a growing worldwide problem for Li-ion fires, particularly in the hot summer. The battery cells contain large amounts of chemical energy in a condensed space with only a narrow separator between the electrodes that are highly flammable. When a battery fails due to overcharging or short-circuiting, the temperature rises and triggers chemical reactions inside the battery called a “Thermal Runaway”.

A white vapor cloud of toxic flammable gases including hydrogen fluoride could be produced, which will explode without warning. In addition, since the Li-ion cells are contained in several layers of aluminum casings, it’s impossible to get water directly onto the seat of the fire. As a result, it’s highly dangerous and difficult for firefighters to extinguish the fire.

Fire crews cannot use traditional techniques to extinguish fires started by lithium-ion batteries, such as those that burned for three days in Australia.

A Thermal Runaway event in a battery system can spread from cell to cell, causing a major fire. Before that, there are early signs, but unfortunately, smoke and gas detectors that are widely employed in battery management systems (BMS) are proven to be unreliable for extracting critical real-time data and fail to provide proper early warnings. Therefore, it is essential to monitor the battery's temperature to stop a cascade failure by intervention.

The main drawbacks posed to this industry are the battery cell’s temperature excursions and non-uniformity. Therefore, as a non-invasive measurement tool, the fixed-mount thermal camera is ideal to get real-time temperature data and the thermal fingerprint of the battery surface for the investigation of Li-ion battery thermal behavior, having a wider temperature range, higher accuracy, and more vivid colors compared to Liquid Crystal (LC).

Minute thermal inhomogeneity can be easily detected with thermal cameras for the analysis of temperature homogeneity and distribution on the battery surface. Using a thermal camera, the BMS can follow the dynamics of the heat evolution during the discharge and charge processes, thus alerting any abnormalities that might lead to a Thermal Runaway, buying time for the system and operators to activate countermeasures.

The FOTRIC thermal monitoring system can protect the Li-ion battery storage through:

  • Automatic alarm triggering when critical temperature thresholds are exceeded

  • Segmentation of image areas for alerting

  • Documentation of alarm situations to analyze potential causes of fire

  • Localization of heat sources, even in dusty or smoke-polluted environments

  • Continuous operation 24 h / 7 without supervision

  • The camera feed can be routed to the control room or other locations

  • Single or multi-camera systems are possible.

A hotspot that is a potential risk of a fire can be determined when the measured temperature exceeds a user-defined threshold. Once set, the 24/7 heat detection cameras can highlight the problematic region in the video image by displaying the area exceeding the pre-defined temperature threshold in a brighter color and alert with a sound.

Hotspot detected by FOTRIC Fixed-mount camera

Lithium batteries stored for a long time without use have to maintain a 50-60% charge state, should be recharged every three months, and charged-discharged once every six months. However, during charge and discharge cycles, batteries are subjected to an increment of temperature, and overcharging or short-circuiting might take place too, which can be detected as hotspots by thermal cameras.

FOTRIC Fixed-mount Thermal Cameras monitor the Li-ion battery storage hall

[1] What is thermal runaway?

[2] Fire risks at battery energy storage facilities.

[3] Early Fire Detection in Warehouses and Assembly Halls.


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