We spotted this brilliant post from René Ruusunen explaining the concept of stranded energy in a lithium battery following a thermal runaway event.
As you can see from the video that René has included with the post, when voltmeter probes are placed on a fire damaged lithium battery, it is very clear to see that stranded energy is present as the display shows a voltage reading of 4.109 DC.
Comments Matt Butcher: “Stranded energy poses a significant potential risk in any electric vehicle or device that is subject to a lithium-ion battery fire. Why? Well, if the battery does go into thermal runaway and the resulting fire is seemingly extinguished there could be stranded energy in the battery that might reignite at any time. And this can happen days, weeks or even months later.
“This is just one of the reasons why we advocate allowing lithium-ion battery fires to burn out completely to reduce the likelihood of stranded energy. By covering the vehicle with a Fire Cloak™ EV fire blanket, this will minimise collateral damage and allow the fire to burn in a controlled and restricted manner. “
Concludes Matt: “If the battery does reignite due to stranded energy the Fire Cloak™ will contain and control any potential fire, minimising damage to nearby property.”