How Is Energy Stored in Batteries?

We use energy constantly – when we're awake, when we're asleep, no matter what we're doing. We tend to take for granted how easy it is for us to obtain the energy required to power devices, appliances, tools, machines, vehicles, and all the things we use throughout the day and night. But how is energy stored so that it's available when we need it?

Let's delve into this topic to understand the basics of this magical concept better.

What Is Energy & How Is It Stored?

If we revisit our memory of high school physics, we may recall that energy is the ability to do work. Energy is the ability of any force to do work. There are many forms of energy, but they can all be categorized into one of two major groups: kinetic energy or potential energy.

Forms of energy

To understand the difference between the two, science teachers often use the example of a rock. A rock that is rolling down a hill has kinetic energy that it could impart to something if it crashed into it. Kinetic energy is the energy of motion.

A rock positioned at the edge of a steep hill has the potential to roll, so we consider that potential energy conserved in the rock.

Electric energy or electricity falls into the category of kinetic energy. Why? Because all electrical energy is in motion. Electrical energy, however, can be converted into other forms of energy we can store. Let's find out how this works!

energy storage dam

While not a rock, water behind a dam is stored potential gravitational energy.

Can You Store Electrical Energy?

No. While you cannot store electricity itself, it can be converted to other forms of energy that are capable of being stored. Then later you can convert that energy back to electricity for use by the consumer.

We can store electrical energy in several ways, including a flywheel (mechanical energy), elevated water or weight (gravitational energy), compressed air (potential energy), capacitors (electrical charge), or, the most common, batteries (chemical energy).

What Is A Battery?

A battery is a storage device that stores chemical energy for later conversion to electrical energy. Every battery contains one or more electrochemical cells. Within those cells, chemical reactions take place, creating a flow of electrons in a circuit. This flow of electrons provides the electric current required to do the work!

Better Understanding Of Batteries – Li-Ion Vs. Li-Po

When we buy gizmos, we try to make sure that they have a good, long-lasting battery. Although, we only look at battery capacities. The formula seems simple – the larger the capacity, the better the battery life, right? But have you ever tried to find out what do terms like Li-ion and Li-Po mean? These abbreviations denote the types of batteries your device packs, and this plays a vital role in keeping your device juiced up. Let’s take a deeper look at these battery types and how they affect our phones and laptops in our daily life.

Lithium-ion (Li-ion) batteries are used in most of our modern-day smartphones. These batteries are made of three different parts, an anode (a negative terminal) made of lithium metal, a cathode (positive terminal) made up of graphite and a separating electrolyte layer between them to prevent short-circuiting. Whenever we charge our batteries, through a chemical reaction, ions from the negative terminal travels towards the positive terminal where energy is stored. As the battery discharges, ions travel back again to the anode.

Ever wondered how our phones stop themselves from overcharging? Well, these batteries are also equipped with a small electronic controller to do just that. Some brands have made developments in reshaping these batteries into layers to gain even more capacity.

A Lithium-polymer (Li-Po) is quite an old technology that you can find in your old, bar phones or laptops. These batteries have a similar structure like Li-ion batteries, but is made of a gel-like (Silicon-Graphene) material which is quite light in weight. Due to its light and flexible characteristics, these batteries are used in laptops and most of the high-capacity powerbanks.

What Are Cylindrical Lithium Batteries?

Cylindrical lithium batteries, as the name suggests, feature electrodes that are encased in a cylindrical cell that is wound very tightly within a specially designed metal casing. This unique makeup helps to minimize the chances that the electrode material inside will break up, even under the heaviest of use conditions.

Issues like mechanical vibrations, thermal cycling from charging and discharging, and the mechanical expansion of current conductors are all things that can affect a battery's lifespan. Therefore, the design of these cylindrical units is intended to help mitigate risk from these and other factors as much as possible.

On the inside of a cylindrical battery, a series of cells are combined and operate in parallel to one another. This is done to help increase both the voltage and the overall capacity of the battery pack.

For these reasons, cylindrical batteries are usually the kind that are found in the aforementioned medical device systems. Smaller, more specially designed cylindrical cells are also commonly found in portable devices like laptop computers. Notably, Tesla also made headlines recently by selecting cylindrical lithium batteries to power its fleet of popular electric cars.