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Lithium-ion
unintended rapid disassembly |
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Bad Lithium Ion
Charging
Basics Most systems using lithium-ion or lithium-polymer batteries
use a two-stage safety system. The first stage is the battery charger, which is designed to safely charge the battery. The
second stage is the safety board, which prevents the battery from damage if the charger goes haywire.
Occasionally for
systems where the battery is not replaceable developers don't put in a separate safety board, but rely on other features of
their internal circuitry to keep the battery safe.
This is what happened to this prototype developed by one of our
customers. They were using a single 900 mAH battery without a safety board. An internal DC/DC converter failed, presenting 6
volts 0.5 amps across the single 3.6 volt prismatic lithium-ion cell.
The cell not only caused the damage shown here,
but filled the room with black soot covered a large area with battery pieces and burned spots on the carpet.
Moral:
please friends, be safe.
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This picture shows the prototype laying on its charging stand shortly after the event. The battery has spewed
its guts. |
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Another view of the ejected battery parts under the original circuit board |
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Here the prototype has been taken off the charging station |
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The more-or-less empty casing of the prismatic lithium-ion battery. |
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Custom design and manufacture of state-of-the-art battery chargers, UPS,
and power supplies for OEMs in a hurry!
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PowerStream Technologies: 1163 S. 1680 West. Orem Utah
84058
Phone: 801-764-9060  Fax: 801-764-9061 |
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© Copyright 2000, 2002, 2003, 2005, 2009 Lund Instrument Engineering, Inc.
All rights reserved |
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