How is energy stored in batteries?

How is energy stored in batteries?


4 Answers

Aarti Gupta
askIITians Faculty 300 Points
9 years ago
Battery can be defined as a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal known as cathode, and a negative terminal called anode. Electrolytes allow ions to move between the electrodes and terminals, which allows current to flow out of the battery to perform work.There are no batteries that actually store electrical energy; all batteries store energy in some other form.Like store energy in chemical form and convert that into electrical energy when needed.
A battery consists of some number of voltaic cells. Each cell consists of two half-cells connected in series by a conductive electrolyte which contains anions and cations.There are two half-cells. One half-cell includes electrolyte and the negative electrode, the electrode to which anions (negatively charged ions) migrate and the other half-cell includes electrolyte and the positive electrode to which cations (positively charged ions) migrate. Redox reactions power the battery. Cations are reduced (electrons are added) at the cathode during charging, while anions are oxidized (electrons are removed) at the anode during discharge.The electrodes do not touch each other, but are electrically connected by the electrolyte.A separator allows ions to flow between half-cells, but prevents mixing of the electrolytes.Two reactions happen simultaneously.The ions transport current through the electrolyte while the electrons flow in the external circuit, and this is how electric current is generated.
Battery may be disposable,then it will produce electricity until it runs out of reactants (same chemical potential on both electrodes) and work in one direction, transforming chemical energy to electrical energy. But the reaction can be reversed in rechargeable batteries which are designed in such a way so that electrical energy from an outside source can be applied to the chemical system, and reverse its operation, restoring the battery’s charge.
Raheema Javed
156 Points
9 years ago
If you look at a battery, it will have two ends; a positive terminal and a negative terminal. If you connect the two terminals with wire, a circuit is formed. Electrons will flow through the wire and a current of electricity is produced.

Inside the battery, a reaction between the chemicals takes place. But reaction takes place only if there is a flow of electrons. Batteries can be stored for a long time and still work because the chemical process doesn't start until the electrons flow from the negative to the positive terminals through a circuit.
A very simple modern battery is the zinc-carbon battery, called the carbon battery for short.

This battery contains acidic material within and a rod of zinc down the center. Here's where knowing a little bit of chemistry helps.

When zinc is inserted into an acid, the acid begins to eat away at the zinc, releasing hydrogen gas and heat energy. The acid molecules break up into its components: usually hydrogen and other atoms. The process releases electrons from the Zinc atoms that combine with hydrogen ions in the acid to create the hydrogen gas.

If a rod of carbon is inserted into the acid, the acid does nothing to it.

But if you connect the carbon rod to the zinc rod with a wire, creating a circuit, electrons will begin to flow through the wire and combine with hydrogen on the carbon rod. This still releases a little bit of hydrogen gas but it makes less heat. Some of that heat energy is the energy that is flowing through the circuit.

The energy in that circuit can now light a light bulb in a flashlight or turn a small motor. Depending on the size of the battery, it can even start an automobile.

Eventually, the zinc rod is completely dissolved by the acid in the battery, and the battery can no longer be used.
Rahul Jiji George
42 Points
9 years ago
“the negative electrode, the electrode to which anions (negatively charged ions) migrate and the other half-cell includes electrolyte and the positive electrode to which cations (positively charged ions) migrate.“ can you please explain this . I thought it was the other way.
shubham sharda
360 Points
9 years ago
An electric battery is a device consisting of two or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal, or cathode, and a negative terminal, or anode

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