Primary battery Facts for Kids

A primary battery or primary cell is a type of battery that you can only use once. Unlike rechargeable batteries, you can't plug them in and fill them up with power again. Once the chemicals inside a primary battery are used up, it stops working and you throw it away. Think of them as single-use power packs for things like flashlights, remote controls, or small toys.

A variety of common primary battery sizes, like those you might use at home.

Primary batteries are still very popular, making up a big part of the battery market. However, rechargeable batteries are becoming more common. Every year, billions of primary batteries are thrown away around the world. Because they contain certain metals and chemicals, batteries can be harmful to the environment if not disposed of properly. Many towns and cities have special rules for how to throw away batteries to keep our planet safe.

Why Rechargeable Batteries are Becoming More Popular
Single-Use vs. Rechargeable Batteries
How Batteries Work: A Simple Look
- What is Polarization?
- Anode and Cathode: The Battery's Poles
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Why Rechargeable Batteries are Becoming More Popular

In recent years, rechargeable batteries have started to take over from primary batteries. This is because rechargeable ones have become cheaper and better. For example, older flashlights used bulbs that needed a lot of power. But now, most flashlights use LED lights, which use much less power. This means batteries last longer, and rechargeable ones make even more sense.

Big battery companies like Energizer and Duracell are seeing changes in the market. Many people are now choosing rechargeable batteries, especially for devices that use a lot of power, like wireless gadgets or cordless tools. It would be too expensive to keep buying new primary batteries for these items all the time.

Single-Use vs. Rechargeable Batteries

Let's look at the main differences between primary (single-use) and secondary (rechargeable) batteries:

Cost Over Time

Rechargeable batteries usually cost more to buy at first, and you also need a special charger. But in the long run, they are much cheaper. You can use them hundreds or even thousands of times. Imagine if you had a power tool that needed new batteries every few hours – it would get very expensive very fast with single-use batteries!

Storing Power

Primary batteries are designed to keep their power for a long time, even when they're just sitting on a shelf. This is because the chemical reactions inside them happen very slowly when not in use. Older rechargeable batteries used to lose their charge quickly. But newer rechargeable batteries, like those found in many phones and laptops, can hold their charge for a long time too.

Power for Strong Devices

Some devices need a lot of power very quickly. Rechargeable batteries, especially types like NiMH and Li-ion, are much better at providing this strong power without losing a lot of their total capacity. Single-use batteries like alkaline or zinc-carbon can struggle and lose more of their power when asked to provide a lot of current.

How Batteries Work: A Simple Look

Inside every battery, there are chemicals that react to create electricity. When you use a primary battery, these chemicals are used up. Once they're gone, the battery is dead.

What is Polarization?

One thing that can make primary batteries stop working faster is something called polarization. This happens when a gas, like hydrogen, builds up on one of the battery's parts (called the cathode). This gas acts like a barrier and stops the battery from working as well. To fix this, battery makers add special chemicals called depolarizers. These chemicals react with the hydrogen gas and turn it into water, helping the battery last longer. For example, manganese dioxide is used in common Leclanché and zinc-carbon batteries.

Anode and Cathode: The Battery's Poles

Every battery has two ends, or terminals, where the electricity comes out. These are often marked with a plus (+) and a minus (-) sign.

The terminal marked with a plus (+) is called the cathode. This is where the electricity leaves the battery to power your device.
The terminal marked with a minus (-) is called the anode. This is where the electricity enters the battery from the inside.

Inside the battery, the anode is where a chemical process called oxidation happens, which releases electrons. The cathode is where reduction happens, which accepts electrons. These electrons then flow through your device, creating the electric current.

Primary battery facts for kids

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