Ever wondered what the best battery storage for solar might be?
There is no doubt that we rely on electric appliances to perform many of our daily routine activities. This is why the demand for electricity is increasing day by day.
Fossil fuels are the major source of electricity generation, but that is not a clean energy source. They pollute the air with green house gas (GHG) emissions. Renewable power generation sources are not net GHG polluters.
Increasing proportions of the electricity generated comes from renewable sources with more residential rooftop solar panels being installed each year. Solar power installations are often subsidised but then so too coal powered generators obtain a subsidy.
We are unlikely to stop subsidizing the use of fossil fuels for power but we might want to leverage the benefits of clean power generation to benefit our future generation's air quality.
Fortunately, with advancing technology, we can use the renewable energy resources in wind, water and sun. The sun is an unlimited power source that is available free to us every day.
Best Battery Storage For Solar Panel
If you install a solar power system, invest in getting the best battery storage for solar power.
Batteries compliment a photovoltaic system by storing the DC energy produced by the solar panels. Energy generated and stored during the daytime is available when the sun sets. This store of energy runs electronic appliances in your house.
In 2018 more home battery storage capacity was installed than the existing supply. There are expectations that in 2019 the trend to installing solar storage batteries will continue.
The solar battery storage trend following the solar PV installation is growing rapidly. Batteries for energy storage usually have one of three chemical compositions. Lead acid, nickel cadmium and lithium ion. In time as the storage size of the VRFB technology is refined into the scale size suited for home solar as low as 8kW the use of vanadium redox flow batteries (VRFB) will increase into residential applications. VRFB are currently restricted to the commercial and utility sized applications.
The first types of batteries listed are more affordable. But, lithium-ion battery is the best battery storage for a solar panel system.
Lead Acid Battery
This type of battery is common as an electrical store in off-grid energy systems.
The batteries store the electrical energy in the form of chemical energy. During use the internal reactions convert stored energy into electrical energy when required. In this battery, the positive and negative electrodes immerse in an electrolytic solution. That solution is sulphuric acid diluted with pure water. The positive electrode plate is lead peroxide. The negative electrode plate is pure lead in sponge-like condition. An external electrical load connects between these plates.
When we connect a load, the molecules of sulphuric acid is split into H+ ions and So4—ions. The hydrogen ions react with PbO2 plate to form PbO and H2O. This PbO reacts with sulphuric acid (H2SO4) and forms PbSO4 and H2O.
PbO2 + 2H → PbO + H2O
PbO+ H2SO4→ PbSO4+H2O
SO4 ions move freely in the solution. Some of them react with pure lead and give extra electrons to become radical SO4 due to which it can’t exist alone and react with Pb to form PbSO4. As H+ ions take electrons form PbO2 and SO4- ions will discharge electrons to Pb plate, there would be a difference between the concentrations of two plates. Due to this there is a flow of current between two plates for balancing this inequality of electrons.
When we disconnect the load, the density of sulphuric acid falls, but hydrogen ions being positively charged move to the electrode connected with a negative terminal of DC source. They take one electron form that source to become a hydrogen atom.
These hydrogen atoms react with PbSO4 to form lead and sulphuric acid.
PbSO4 + 2H → H2SO4 + Pb
SO4- ions move towards the electrode connected to DC source. They give their extra electrons to become radical SO4 and these radicals react with PbSO4 to form PbO2 and H2SO4.
PbSO4+ 2H2 + SO4 → PbO2 + 2H2SO4
Why Are Lead-Acid Battery Used?
Advantages of Lead-Acid Battery
Disadvantages of Lead-Acid Battery
Lithium-ion batteries are an advanced technology form of solar batteries.
Lithium-ion batteries are displacing the lead-acid batteries for solar storage.
The main reason is deep-cycling capability. That means higher recharging and discharging rates and longer lifespan.
Lithium-ion is the best battery storage for solar panels.
What Are Lithium-ion Batteries?
The battery uses lithium ions to store the electrochemical energy.
That energy can convert into electrical energy when required.
Standard batteries have anode (negative terminal), cathode (positive terminal) and electrolyte (channel). Anodes are usually carbon or another similar non-metal. The cathode is a metal oxide such as cobalt oxide and the electrolyte is a solution of lithium salt and water.
How Does It Work?
The battery components exist in a container. To Charge the battery you connect an external power source. This causes lithium ions at the anode and electrons will move towards the cathode.
When we disconnect the external power source, the reverse process is able to occur.
When you connect an external load you complete the circuit. Electrons will flow through the external circuit. The ionized lithium atoms in the anode separate from their electrode. The lithium ions move toward the cathode through the electrolytic solution. Lithium ions combine with the cathode to become neutral.
Cathode Electrode Reaction:
CoO2 + Li+ + e- LiCoO2
Anode Electrode Reaction:
LiC6 C6 + Li+ + e-
LiC6 + CoO2 C6 + LiCoO2
Why Are Lithium-ion Batteries Better Than Other Batteries?
Advantages Of Lithium-Ion Batteries
Disadvantages of Lithium-Ion Batteries
How Much Will A Lithium-ion Battery Setup Cost?
There is a wide range of lithium-ion batteries available in the market and their prices vary.
The total cost of setting up a solar system with batteries depends on the brand of battery you are choosing. They appear to be the best battery storage for solar. Fortunately the prices will reduce over time.
For example, if you choose a 14kWh system with Tesla battery, then it costs around $USD6,560 (dependant on location and set up). To give a rough price, a 5kW photovoltaic system with a battery ready inverter costs around $8000. If you add powerwall2 battery to this, then that will cost double to around $16,500.
We know it is difficult for the average household to invest in the order of $16,500 at one time. There are benefits over costs that make it worth the investment.
Things To Consider When Choosing The Best Battery Storage for Solar Panels
There are different types of batteries in the market that look similar. They range from low quality to high quality batteries.
Their prices vary depending on the size, brand, and type of battery.
You have so many options, it almost becomes a problem to decide which one to choose.
If you are not technically a battery buyer when it comes to choosing one, then consider the following factors:
What Is The Future Of Lithium-Ion Batteries?
In 2018, the lithium-ion rechargeable battery celebrated 27 years in production.
It's become the best battery storage for solar panel. The lithium-ion rechargeable battery has seen sales and growth over that 27 years. It has displaced many traditional batteries for solar storage. The lithium-ion battery is gaining popularity due to its high efficiency and lifespan.
This quality of lithium will lead to the growth of electrification storage. That will happen in homes and mini-grids as part of decentralized energy systems. But we will see it also go forward in cars and buses.
Lithium is the lightest metal with the lowest reduction potential. That makes lithium batteries superior to other batteries. Also, lithium is abundant in earth deposits and we can use it for another 400 years. The battery technology is cheap compared with other battery technologies.
The most popular type of lithium battery is lithium ion battery. It has an unbeatable combination of higher energy and power density.
Recent developments in batteries reflect that the lithium batteries are continuously improving. Their improvements in energy, safety, power capability and cost mean a long future for lithium batteries. The price of lithium-ion batteries will continue to fall in real terms and its power density will increase by 20%.
With the ongoing concern for global warming an investment in a Solar PV system is an environmental one. These changes to battery price and efficiency will further add momentum in the field for using Lithium-ion in electric vehicles and storage of solar generated power. That will mean support continues for investing in Lithium-ion as the best battery storage for solar generated power.