What are solar batteries made of?

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Developing technology for solar home storage batteries is becoming more efficient and economically feasible. Lead-acid, nickel-based, flow batteries and lithium-ion batteries are the four most popular types of home storage batteries.

Lithium-ion batteries are the new and upcoming battery of choice, with a better energy density and a longer lifespan than lead-acid batteries. However, they are also the priciest. Although modern technologies are replacing lead-acid batteries, they are still reliable. In recent years lead-acid batteries have been built using hazardous materials.

Therefore, nickel-based batteries have better environmental and safety benefits. A more recent technology, flow batteries have a long lifespan, a high energy density, and the capacity to function at various temperatures. However, they are also expensive.

How is solar battery technology evolving, and what are solar batteries made of?

A solar home storage battery is very similar to a car battery. This means that the charge controller or battery management system chooses a voltage compatible with the battery’s voltage.

The battery management system also regulates the PV array’s voltage output to supply the right amount of electricity to the battery.

This electric current is subjected to an energy conversion process during charging. This process, when charging, transforms electrical energy into chemical energy. During discharging, chemical energy is converted back to electrical power.

Usually, this process also requires some energy, meaning energy will be lost during the charge and discharge process. As a result, we never will retrieve 100% of the power we have charged the battery.

Today four main types of solar batteries are available for you to purchase. These are:

  • Lithium-ion
  • Lead-acid
  • Nickel-based, and
  • Flow batteries


Lithium-ion batteries, which were initially discovered in 1912, are made up of several different raw materials, mainly lithium, graphite, cobalt, and manganese.

Furthermore, the actual battery consists of three main components: the anode and cathode, a separator between two electrodes, and an electrolyte.

Due to the increase in EV interest, lithium-ion batteries are considered the ‘newer’ and more advanced battery technology. As EV producers popularised this battery technology, many solar battery manufacturers also began to use this technology in products such as Tesla’s Powerwall and LG’s RESU batteries.

Lithium-ion battery technology is constantly evolving as the electric car industry continues to push large amounts of research funds towards their ongoing development.

Furthermore, their higher energy density has overtaken Lead-acid batteries as the most popular battery choice. They also display a longer lifespan, with an average warranty life of 10 years.

In saying this, they are also the most expensive solar battery option. However, their increase in popularity and production numbers should lead to eventual decreases in price. Read our FAQ on why battery prices have not been reduced as yet – here.

Lead-acid batteries 

Lead-acid batteries are the original technology of the solar world, discovered in the early 1800s. They are considered ugly and bulky but dependable and trustworthy.

The primary materials of this battery are; metallic lead, lead dioxide, lead sulphate, and sulfuric acid. Similar to the Lithium-ion battery, this battery also consists of two electrodes. However, they are submerged in an electrolyte of sulfuric acid.

Also known as ‘deep-cycle batteries, ‘ these technology pieces are mainly used today for off-grid solar storage. However, their popularity is slowly decreasing as newer, more evolved technology, such as the Lithium-ion battery, emerges.

lead-acid batteries
Lead-acid batteries are slowly declining in popularity

Nickel-based batteries

These batteries have been around since the late 1800s; however, they have not been as popular as lead-acid battery technology. The primary material for these batteries is Nickel Cadmium, which is their biggest downfall as it is considered very toxic.

In saying this, there have been recent battery improvements by GridEdge. They are aiming to increase the environmental and safety benefits of the battery. Although toxic materials are toxic, they are fully sealed and safe. The storm has been used for residential, commercial, and off-grid solar storage due to its ability to operate at extreme temperatures. This is a benefit very relevant for Australia. Furthermore, it works on a simple battery system requiring little maintenance.

Flow batteries

Flow batteries are a relatively new technology in the solar battery market. The primary materials involved in these batteries are vanadium, iron chromium, zinc-bromine, and zinc ion.

The name ‘flow’ comes from the technology having a water-based electrolyte liquid. They are pretty significant, which has led to them having a higher price. However, their technology has been evolving recently, and an Australian company has produced an excellent residential solar battery known as the ZCell.

Furthermore, these batteries can have all their energy used, meaning they can be discharged next to empty without damaging the current technology, which the other battery technologies struggle with.

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