Short circuit in batteries: how does it happen and how can you prevent it?
You turn on the oven and suddenly *poof* the lights go out. The main switch trips as soon as a short circuit occurs - in this case in the oven. But what about batteries? Is a short circuit also possible here? And what precautions can you take?
What is a battery?
A battery can best be described as a chemical power source that produces a limited amount of electrical energy, wherever you need it. The electrical current that comes from the socket is sourced from a power plant. (Or from renewable sources such as solar panels and wind turbines.) The energy from a battery is produced by the chemical substances inside the battery until the battery is 'depleted'.
What's inside a battery?
Let's now take a look inside. Each battery consists of one or more cells. And each cell consists of four components:
- two electrodes (conductors)
- an electrolyte, a chemical substance between those electrodes
- a separator between the positive and negative electrode that prevents internal short-circuiting.
Together, they are enclosed in a metal or plastic casing. On the outside of the battery, there are two poles, marked with a plus (the cathode) and a minus (the anode).
How exactly does a battery work?
As soon as you connect the poles of the battery in a circuit, e.g. in a flashlight, the battery is activated. Chemical substances in the electrolyte then convert into others. Ions (atoms with too few or too many electrons) are formed that contribute to the chemical reactions in the electrolyte. At the same time, electrons flow from the negative pole to the positive pole via the external circuit. The flashlight turns on!
This process continues until balance is achieved between the elements at the - and + poles. Then the ions stop moving through the electrolyte and the electrons stop flowing. The battery is empty.
What about a rechargeable battery? In this type, the chemical processes are reversible. By applying electrical voltage, you can force the electron flow in the opposite direction and reverse the chemical reactions. In short: you store energy again.
What is a short circuit?
Electricity thus flows from pole to pole in a battery. If the positive and negative poles of a battery come into direct contact with each other, a short circuit occurs. Electrical current follows the path of least resistance. When the two poles make contact, the current will immediately seek an exit along this path.
Can I get shocks from a battery myself?
Grab a full battery and place one finger on the positive side and another on the negative side. Do you feel anything? Probably not. But did you really feel carefully? When you hold both sides of a battery (positive and negative), a small amount of current flows through your body.
However, the electricity is very weak (much weaker than mains power) and there are no metal conductors inside you. The larger the battery, the greater the chance that you might feel something. Also, if you wet your hand you can increase the effect and feel a gentle tingling from the current. Only do this with small alkaline batteries (AA or AAA), because electricity is fascinating, but never child's play!
In conclusion: you won't get shocks from a battery, but there are still several steps you can take to prevent short circuits in batteries.
How can you prevent a short circuit in batteries?
Since contact between the negative and positive poles of a single battery is the culprit, this should always be avoided. Here are some handy tips:
- The poles of a button cell are very close to each other, which increases the chance of a short circuit when you store them with other batteries. Therefore, stick button cells on a piece of tape. Much safer!
- The 4.5 V and 9 V batteries both have + and - poles that are very close to each other. If a button cell gets stuck between the two poles of a battery, this can also lead to a short circuit. Get that tape out of the cupboard and cover the poles.
- If you drop a device with batteries onto the ground, it might also cause internal damage. After the fall, check whether the battery compartment and the batteries are still intact.
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