Solar batteries can store the excess electricity your solar panels generate to power your home. These batteries can also connect with the electricity grid to charge themselves or add power back into the grid if excess electricity is generated. This article will cover the working, chemistries, types, features, and benefits of solar batteries.
Battery Chemistry
It is the combination of chemicals that facilitate reactions within the cells of a battery, allowing the conversion of electrical energy to chemical energy and vice versa. Different types of batteries have varying battery chemistries, which affect the backup power storage capacity and power level of these batteries.
Types of Batteries
Rechargeable batteries can be charged and discharged countless times. They have a specific lifecycle after which they can’t hold a charge. Solar battery banks have these batteries made for regular use and have a long life.
Typically, solar batteries can handle the large power supply from the solar panels, store it, and provide it to the devices in your home if needed. However, the real comparison boils downs to the longevity and capacity of a battery.
Unlike traditional single-use batteries, rechargeable batteries have chemicals that allow the reversal of charge and retain it rather than deteriorating completely.
Not charging a battery properly, charging it at a voltage, or with a charger that is not suited to it can result in overheating and damage due to the destructive reactions in the cells.
Different Battery Types
The most common five types of solar batteries in the market are:
- Flow Battery.
- Nickel-Cadmium.
- Lithium-Iron-Phosphate (LFP).
- Lead-Acid.
- Lithium-Ion.
Less common options include Nickel-Zinc and Nickel-Metal hybrid batteries. They lack popularity because they possess low durability and a smaller capacity than the options listed above.
Flow Battery
This battery has two tanks of hydrogen and liquid bromine solution pumped through a membrane between two electrodes. This chemical solution also contains ions, and a charge difference is created by the transference of ions, which powers the cells.
This battery needs ample space to store the tanks that house the chemicals, the electrical components used by those tanks, and the pipelines they use to pump and transfer the liquid through the membranes to the terminals.
Pros:
- Ample space between different components decreases the electrolytes’ interaction, increasing the lifespan (nearly limitless lifespan).
- Significant space is available due to the size of the tanks.
- There are extensive facilities to store more batteries with larger tanks and electrolytes.
- Appropriate for large-scale storage.
- Zero flammable liquids.
- Flexible layout.
- Advanced technology.
Cons:
- Frequently exhaustive electrolytes.
- Large area needed for separate chemical tanks.
- Expensive.
- Large membrane separators are required to increase charge and discharge rates.
- Low energy density.
Nickel-Cadmium Battery
These batteries pack a lot of power and are really efficient. They are primarily used in aviation, industrial, and transportation applications. The batteries are made of cadmium and nickel mixed in an alkali solution that discharges and charges the elements as negative or positive.
Advantages:
- Needs less maintenance.
- Long cycle life.
- Wide temperature range.
- High recyclability.
- Lower self-discharge rate.
- Vented nickel-cadmium batteries can live upto 20 years or more and can function in temperatures of −20°C to 45 °C.
Disadvantages:
Cadmium is highly toxic and harmful. It is a heavy metal and has to be handled by professionals trained in hazardous waste removal. Due to its toxic nature, it’s been banned by the European Union and is only used in medical equipment. Other disadvantages include:
- Needs to be stored away from wet areas.
- Terminals should be kept clean.
- Sealing the terminals to keep them clean can lead to memory loss and higher self-discharge.
- Increased electrolytic resistance.
- Nitrogen impurities result in increased self-discharge occurrence.
- Overcharging leads to the loss of water in gaseous form. This decreases the capacity of charge being held in the cells.
- Using cheap charging devices harms the cells due to overcharging, decreasing longevity.
- High cost.
Lithium-Iron-Phosphate (LFP) Battery
This battery comprises iron, phosphate, and lithium, interacting with the graphitic carbon electrodes to start a chemical reaction needed to discharge electricity and store it. It's an excellent alternative to lithium-ion batteries due to its low price and toxicity.
Benefits:
- Environment friendly.
- Decreases carbon footprint.
- Decent lifespan and ageing.
- Lower cost.
- Great thermal stability.
- Higher peak power ratings.
Drawbacks:
- Requires timely maintenance to ensure peak performance.
- Needs consistent temperature control.
- Needs protection from temperature and elements.
- Faces problems with safe transport.
- Deep discharge issues.
- Doesn't perform well in low temperatures.
- Decreased electrical conductivity.
Lead-Acid Battery
These batteries have cells submerged in water and sulfuric acid with porous lead. This battery operates by converting lead into lead sulfate and vice versa during the charging and discharging.
Advantages:
- Lower cost.
- Long life cycle (can last 3-12 years depending upon maintenance).
- Deep cycle capability (can discharge more frequently).
- 85% efficacy (compared to other rechargeable battery types).
Disadvantages:
- Decreased charge ability in extremely low temperatures.
- Sulfur spillage is toxic to the environment, animals, and humans.
- Frequent motion can damage the electrodes attached to the soft lead terminals.
- Water and electrolyte loss due to the gassing process.
Lithium-Ion Battery
The most popular and affordable version of rechargeable batteries today. They are very adaptable and versatile, which is why you’ll find them in most electronics nowadays. The solar cells inside these batteries have layered electrolytes and lithium compounds. The lithium ions travel via the electrolyte to the positive side, where they discharge and move back to the negative side when the charging process occurs.
Pros:
- Minimal charge loss during inactivity.
- Higher energy-to-weight ratio.
- Longer lifespan.
- Higher efficiency.
- Needs less maintenance.
- High energy density (holds more power).
Cons:
- Higher risk of fires and overheating.
- Low resiliency.
- Toxic to the environment and all living things due to lithium. It can cause poisoning, burns, and allergic reactions.
The Right Solar Battery For You
After carefully considering the positives and negatives of all the battery types listed above, many people would choose lithium-ion batteries for storing solar energy. They have a long lifespan, high capacity, and occupy less space than other batteries. If you’re low on cash, lead-acid batteries might be a better and more affordable choice. However, they are an older technology and might not work with a high-tech setup.
Solar Storage And Battery Chemistry
You can decrease your dependence on the electrical grid by buying battery systems for your
residential solar power setup. Solar batteries can provide significant support to solar panels in powering your home.
Your savings depend upon your choice of solar battery. You need to understand the different battery chemistries and compositions to make a well-rounded choice. This is where the five battery types come in with their advantages and disadvantages so that you can select the one which will best serve your purpose.