The lithium-ion batteries (Li-ion) are generally extremely safe. But very often we read about various explosions, like then with the Galaxy fiasco Notes 7 of Samsung or the latest recall of HP notebook computers. But what about the specific batteries?
Rechargeable lithium-ion batteries (Li-ion), are the batteries found in laptops, smartphones, tablets και σχεδόν κάθε άλλο gadget διαθέτετε. Τι συναντάμε σε αεροπλάνα και ηλεκτρικά cars. Without lithium-ion batteries, we wouldn't be able to do much of what we do, in places that don't have power outlets.
What's inside a lithium-ion battery?
To understand why we sometimes hear about explosions in lithium-ion (Li-ion) batteries, you need to know their structure. Inside every lithium-ion battery, there are two electrodes, the positively charged cathode and the negatively charged anode separated by a thin sheet of "micropermeable" plastic that keeps the two electrodes separate without touching.
When you charge a lithium-ion battery, the lithium ions push electricity from the cathode, through micro-holes in the separator, into an electrically conductive liquid, and on the rise. When the battery discharges, the exact opposite happens with lithium ions flowing from the anode to the cathode. This is the reaction that powers your laptop.
Small batteries, such as those on smartphones, usually have only one lithium-ion cell. Larger batteries, such as laptops, usually have between 6 and 12 lithium-ion cells. Batteries in electric cars and airplanes can have hundreds of cells.
What makes a lithium battery explode?
The same thing that makes lithium-ion batteries so useful is also what gives them the ability to catch fire or explode. Lithium is very good for energy storage. When released slowly, it feeds the phone you all day. But when released at once, the battery may explode.
Most fires and explosions of lithium-ion batteries are referred to as a short circuit problem. This happens when the plastic separator fails to separate the rise and fall. And of course when they meet, the battery starts to overheat.
There are several reasons why the separator may fail in his work:
Poor design or defects construction: The battery is not properly designed as it was Galaxy Note 7. In this case, there was not enough space for the electrodes and the battery separator. On some models, when the battery heats up slightly as it charges, the electrodes bend and cause a short circuit. Even a well-designed battery can fail if the quality control is not followed with "reverence" or if there is a defect in the construction.
External factors: Extreme heat almost guarantees some battery failure. Batteries left too close to a heat source have been known to explode. Another external factor that can cause a lithium-ion battery to fail. is if you drop the device many times. Thus there is a possibility of damaging the separator and causing contact of the electrodes. If you puncture the battery (accidentally or intentionally), then you will almost certainly cause a short circuit.
Problems charger: A poorly built or poorly insulated charger can also damage a lithium-ion battery. If the charger produces heat near the battery, it can cause damage.
Thermal leakage and multiple cells: This particular issue is not related to single cell batteries, such as those found in most smartphones (the iPhone X actually has two cells).
Once a cell overheats, we may have a domino effect called "thermal escape" or "thermal runaway." For batteries with hundreds of cells, such as those of the Tesla Model S, a heat leak can be a really big problem.
