Battery Safety
Lithium-ion batteries can rupture, ignite, or explode when exposed to high temperature environments - including areas that have prolonged exposure to sunlight. Short-circuiting a Li-ion battery can also lead to fires and explosions. As such, any attempt to open or modify a lithium-ion battery's casing or circuitry is very dangerous. Li-ion batteries contain safety devices that protect the cells inside from abuse. If damaged, the battery becomes a risk to experience an enornous spike in temperature and ignite or explode.
Contaminants inside the lithium-ion cells can compromise the effectiveness of these safety devices. |
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For example, the mid-2006 recall of approximately 10 million Sony batteries used in Dell, Sony, Apple, Toshiba, Acer and Sharp laptops was due to internal contamination from metal particles.
Under certain circumstances these particles can pierce the cell's separator, causing the cell to short and rapidly convert all of its energy to heat. The resulting exothermic oxidizing reaction increases the cell's temperature to a few hundred degrees Celsius in a fraction of a second, causing the neighboring cells to heat up, starting a chain thermal reaction (a.k.a. thermal runaway). |
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