There are many factors that are taken into account when choosing solar cells for photovoltaic installations. The two main indicators when choosing a battery are the type of battery and its purpose. Today we look at the main types of electricity storage solution.
Types of storage batteries
There are four main types of battery technologies that are used in hybrid solar installations:
- Lead acid batteries
- Lithium-ion batteries
- Nickel-based batteries
- Flow/redox batteries
Each of these battery backup technologies has its own set of unique characteristics.
Lead Acid Batteries (VRLA)
Lead-acid batteries, also known as batteries, are the tried and true technology in the world of solar batteries. These deep-cycle batteries have been used to store energy for a long time—since the 1800s, in fact. And they’ve stuck around because of their reliability. There are two main types of lead-acid batteries: flooded lead-acid batteries and sealed lead-acid batteries.
The main advantages of this type of battery are that they are still the cheapest option for energy storage, which makes them the most cost-effective and reliable. Also, since the technology has been around for years, they can be easily discarded and recycled. The disadvantages are that this type of battery requires ventilation and regular maintenance to work properly, which increases the chances of battery leakage. This in turn limits the ability of the batteries to be installed, as they cannot be monitored far outside the installation. The life of this type of battery is between 5 and 10 years. The reliability of lead-acid batteries is best suited for off-grid solar installations or for emergency backup storage.
Lithium-ion batteries (LMO, NMC, NCA, LFP)
Lithium-ion batteries are one of the most popular and used today. As electric vehicles began to grow in popularity, EV manufacturers realized the potential of lithium-ion as an energy storage solution. They quickly became one of the most widely used solar power banks. The main advantage of lithium-ion batteries is that they do not require regular maintenance. They also have a higher battery energy density, meaning they can hold more energy in a smaller space than a lead-acid battery. Lithium-ion batteries have a longer life cycle – they have a guaranteed service life of at least 10 years. This longer life is because Li-ion batteries have a greater depth of discharge, so you can use more of the energy stored in the battery before it needs to be recharged. The disadvantage is still the price and the unexplored possibilities for their recycling. Lithium-ion batteries are best for residential or small industrial solar installations because they can hold more power in a limited space.
Nickel Cadmium Batteries (NiCd)
Nickel-cadmium (Ni-Cd) batteries are not as widely used as lead-acid or lithium-ion batteries. This type of battery was first used in the 1800s, but underwent a change in the 1980s that greatly increased the amount of energy they could store. They are a favorite among the aviation industry. The main advantage of Ni-Cd batteries is that they are durable. They also have the ability to work in extreme temperatures. In addition, they do not require complex battery management systems and are generally maintenance free. The biggest drawback is the toxicity of cadmium, its use is even banned in some countries, which makes them almost impossible to recycle. They have a wide range of applications, such as electricity storage for utilities.
Redox flow batteries (RFB, HFB)
Redox batteries are a relatively new technology in the energy storage sector. They contain a water-based electrolyte fluid that flows between two separate chambers or reservoirs in the battery. When charging, chemical reactions occur that allow energy to be stored and subsequently discharged. However, their larger size makes them more expensive than other types of batteries. The high cost, combined with the large size, makes it difficult to adapt them to residential use and small solar installations. The main advantage of redox batteries is that they have 100% depth of discharge. This means that the entire amount of stored electricity can be used without harming the technical stability of the battery. They do not need maintenance and have the longest service life – 30 years. Unfortunately, however, this type of battery is much more expensive than other types of solar batteries, due to the low storage capacity, which makes their overall dimensions large. Redox batteries are suitable for large solar parks and installations.
There are a number of different potential decision criteria and comparison points to make when evaluating your energy storage options. Here are some of the most common decision criteria, as well as which battery features are most important if those criteria apply to your situation:
- If you want to power more consumers at once, look for a high power solar battery
- If you want to power a larger energy consumer, look for a battery with high instantaneous power
- If you want to run your home or manufacturing plant with a solar battery for a longer time, look for a battery with a higher usable capacity;
- If you want to get the most out of every kilowatt-hour of electricity you put into your battery, look for batteries with higher bi-directional exchange efficiency;
- If you’re limited on space and want to get the most storage from the least amount of space, look to lithium-ion nickel-manganese-cobalt (NMC) solar cells;
- If you want the battery with the longest life that you can cycle the most times, look for lithium iron phosphate (LFP) batteries;
- If you want a battery with the absolute highest safety rating possible (don’t worry, they’re all safe!) look for LFP solar batteries.
Making a decision on the choice of electricity storage technology will affect the entire energy system. If you are still not sure, do not hesitate to contact us for more information about choosing storage batteries according to the technological features of your solar installation.