How does a rechargeable battery work?
Our devices are increasingly losing the wire. Literally that is. To power all those devices, rechargeable batteries are often a good alternative to traditional batteries. But what are the main differences between the two, besides the fact that one can be recharged and the other cannot?
NiMH = NoRM
Although rechargeable batteries may seem like the new normal today, the concept has existed for much longer. In 1859, the Frenchman Gaston Planté assembled the first rechargeable battery: a lead-acid battery. Today, there are about ten types of rechargeable batteries. A large part of these are not found in stores, but are used, for example, in satellite probes or for industrial applications. Most rechargeable batteries - we mean the familiar AA and AAA types - are primarily nickel-metal hydride (NiMH) batteries. Previously, nickel-cadmium (NiCd) was the standard, but this type has almost completely been phased out today. This is partly because they lose their capacity more quickly.
How does a battery work?
A battery emits current when it is in a closed circuit. That means when the positive and negative poled are connected through a consumer, such as a light bulb. Closing the circuit initiates a reaction at the negative pole, which starts producing electrons, while a second reaction consumes electrons at the positive pole. In the battery, there's a separator between the negative and positive poles, which prevents the electrons from moving between the negative and positive poles inside the battery, thereby also preventing internal short circuiting. The separator only allows ions to pass through. The only way for electrons to travel from the negative to the positive pole is through the circuit outside the battery. When this happens, a voltage difference occurs causing the lamp to function.
At the same time, other things also happen inside the battery. The electrons that flow 'from outside' to the positive poles engage in a reaction. This reaction causes the ions to move through an electrolyte (a conducting liquid inside the battery) to the other conductor. At the negative pole, a reaction also occurs which generates electrons that are again delivered to the external circuit. This process continues until the electrodes become saturated and no longer engage in reactions. At this point, the battery is depleted.
And how do they recharge?
To recharge batteries, the discharging process is simply reversed. The supplied electricity is converted back into a chemical reaction. The charger removes the negatively charged electrons from the positive ole and transfers them to the negative pole. As energy flows through the battery, the active materials return to their initial state, allowing the discharge process to begin again.
In a battery, electrical energy (power) is generated through a chemical process. The electric current flows due to a chemical reaction between two materials separated by a separator. Naturally, this means that you need different raw materials to facilitate this process. These substances are not found in traditional batteries. The raw materials in rechargeable batteries are somewhat scarcer and require more processing. Also, the actual production process is often more expensive and slower. This partly explains why rechargeable batteries are significantly more expensive than their non-rechargeable counterparts.
When do I choose rechargeable and when not?
That depends on what you want to use the batteries for.
Non-rechargeable batteries
For energy-efficient devices (calculator, clock, or remote control) that require relatively little power, it is more evident to use a primary battery. For devices that must always be ready, such as smoke detectors and flashlights, it is also better to use primary batteries. These lose, unlike rechargeable batteries, little power over time (the 'self-discharge').
Rechargeable batteries
For devices that require a lot of power in a short time or that are used very often and intensively, you are better off with rechargeable batteries. Consider devices like gaming consoles, music players, your child's favorite toy, walkie-talkies, and digital cameras.
