1 Warning signs and preventive actions Presented by Peter DeMar Thermal Runaway
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Warning signs and preventive actions
Presented by Peter DeMar
Thermal Runaway
Thermal runaway
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If thermal runaway does not scare you, then you are…
Thermal runaway
Brand new to the stationary battery industry
Ignorant of thermal runaway disasters
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Thermal runaway
Someone who realizes there are always warning signs
Knows what they are
Is applying the correct preventive measures
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What is thermal runaway?
CAUSED BY
Excess of battery charging current
Produces more internal heat than the battery can dissipate
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Thermal runaway can be detected, prevented and recovered from
Recovery = green benefit
RECOVER a battery from thermal runaway and continue to use it
Reduces carbon footprint for that battery
GREEN benefit for the environment
Good for your budget
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The monster appears unexpectedly?
“ It occurredwithout
warning ”
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The monster appears unexpectedly?
There is ALWAYS an early warning
We just did not understand the signals • They are obvious
• There for many months!
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What are these early warning signs?
Increase in float current • Starts very slowly
• Increases over time
• Current through the battery
• Not necessarily = charger meter
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What are these early warning signs?
Increase in float current • Starts very slowly
• Increases over time
• Current through the battery
Gradual increase in the temperature differential between cells and ambient
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What are these early warning signs?
Increase in float current • Starts very slowly
• Increases over time
• Current through the battery
Gradual increase in the temperature differential between cells and ambient
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These two items – when properly checked and tracked – will provide substantial warning so that
you can take necessary actions to prevent a thermal runaway
What causes thermal runaway?
Negative plate discharge and sulfation
Increase in float current
Dry out of cells
Loss of electrolyte contact through AGM from plate to plate
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= inability of cells to dissipate internally generated excess heat
Preventing thermal runaway
IEEE 1188 standard
Maintain overall float voltage correct for ambient temperature
Track temp. differential between cells and ambient monthly
Track float current monthly
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Contact us for guidance on what “typical”float current should be for your battery
How to take the measurements
Hand held meters
Monitoring, such as the BEM device
Keep accurate records and keep track of records
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Track readings for the life of the battery
Recovery after thermal runaway
Re‐establish proper saturation
Remove sulfates from the negative plates
Install catalysts
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You can take a structurally intact battery from full‐blown thermal runaway and turn it back into
a usable and reliable battery
Preventing thermal runaway
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Re‐establish proper saturation
Remove sulfates from the negative plates
Install catalysts
You can prevent thermal runaway by applying these
actions early
Who and what
Now that the early warning signs of thermal runaway are so easily observed, just who is responsible when it occurs?
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Who and what
Now that the early warning signs of thermal runaway are so easily observed, just who is responsible when it occurs? YOU ARE.
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Who and what
Now that you understand that there is a means of recovering a battery from thermal runaway• You can be pro‐active instead of re‐active
• You have time to determine just what actions are best for you
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STATIONARY POWER SERVICES FOR INDUSTRY
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(800) 221‐7123www.batteryresearch.com
Experts in DC Systemsa WBE Enterprise
(800) 221‐7123www.batteryresearch.com
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