And once again Friday is here, along with the weekly "A Taste of Physics" column — number 18.
This week: how batteries are built, and why they explode when pressure is applied to them.
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To understand why they explode, we first need to understand the internal structure of a battery.
A battery is made up of an anode (negatively charged), a cathode (positively charged), and an electrolyte that separates them.
When an external connection is made between the anode and the cathode — for example, when we connect the battery to a phone for charging or operation — electrons (which carry a negative charge) flow from the anode to the cathode through the external connection.
At the same time, the positive ions that remain in the anode travel to the cathode through the electrolyte, where they reunite with the electrons received via the external circuit and re-form stable atoms.
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Pressure on a battery causes it to explode in several stages:
- The battery's internal structure collapses, creating direct contact between the anode and the cathode.
- Because there is a high voltage (volts) between the anode and the cathode, direct contact between them causes a large amount of electrical current to flow all at once.
- This current flow generates a great deal of heat, as it encounters resistance while passing through the material (resistance measured in ohms).
- The heat in turn causes the electrolyte to break down — a process that releases additional heat as well as gases that accumulate inside the battery.
- As the circuit continues, the heat and pressure inside the battery build up until they rupture the battery's outer casing in the form of fire and intense heat.
Have a pleasant and peaceful weekend 😊
#ATasteOfPhysics