This is a beginners guide to lithium batteries which have been used for years in smart phones and power tools because they are powerful and lightweight. Companies like Tesla and Lithium Battery Systems have developed the control systems to bring the power of lithium battery chemistry into batteries designed for cars, boats, RV’s, caravans and home storage. This wave of new battery technology is long overdue with lead-based batteries being the only choice for over 50 years. Lithium batteries are revolutionising the sector and here we explore why all the smart users are moving to lithium battery systems.
What is lithium?
Lithium is the lightest known metal and highly reactive which makes it perfect for storing electrical charge. Lithium is found combined with other elements in ores around the world and Australia has vast high-quality deposits. You may be hearing about several lithium projects going on right now around the country as companies take advantage of growing global demand for lithium.
Australia is not only one of the largest lithium miners in the world but is also starting to process more of it here before exporting it to countries like China and the USA, to be made into battery cells.
Why is lithium used in batteries?
Batteries have an anode and a cathode that allows the transfer of electrons to store and provide electrical energy. Lead and acid have been the chemical mix that have been used for decades. Wet cell, deep cycle, AGM and Gel are all variants of the same chemical lead acid mix.
Lithium has physical, thermal and electro-chemical properties that make it ideal for use in batteries. Physically, lithium is the least dense solid element know to man, which means batteries made using lithium are much lighter. Lithium also has the highest specific heat of any solid element, making it an efficient heat transfer agent.
But perhaps the greatest advantage of lithium is that because it is highly reactive it can pack more power than other battery types. Lithium cells can produce a voltage up to 3.6V and are put together to create batteries that are 12V/24V/48V systems.
What lithium cells are best and why?
There are several types of lithium-ion chemistry on the market, including lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide and lithium iron phosphate. The cells come in different packages including cylindrical and prismatic. Cylindrical look like bigger AA batteries while prismatic cells are rectangular about the size of a small book.
Lithium iron phosphate is the the safest chemistry and prismatic cells are the most efficient and mechanically robust way to package the stored energy.
A quality Battery Management System (BMS) controls the whole system (more about this next month). Beware of lithium batteries using the small cylindrical cells soldered together in plastic boxes using a cheap low quality BMS.
So why use lithium over lead acid batteries?
Lithium batteries allow you to pull far more amps out of the same size battery. This allows you to run all of your appliances that require a lot of power. Good quality lithium batteries are capable of 200A continuous output and can peak at 500A which is ample for all household appliances and even air conditioning systems.
Lithium batteries are less than half the weight of the equivalent lead acid battery. This is an important consideration for recreational vehicles and boats. Light weight portable lithium batteries are also an advantage when camping. Carrying a 10kg battery is a lot easier than carrying a 32kg of lead!
Lithium batteries provide more usable capacity than lead acid batteries. Deep discharging does not affect the life of a lithium battery the way it does with lead acid batteries. You can use the battery longer before needing to recharge, without damage to the battery.
Lithium batteries are rated for 2,000 – 5,000 cycles and much more if used carefully, giving you several times the life expectancy of standard lead acid batteries.
COST EFFECTIVE OVER LIFE CYCLE
When considering the usable capacity and lifespan of lithium batteries, they work out cheaper than lead acid. When you add the cost and inconvenience of refitting new lead-based batteries every few years the total cost of ownership over the long term is far better with lithium batteries.
Lithium batteries charge more efficiently, and don’t require as many stages during charging. Therefore, they will charge faster, and hold more of the energy from solar panels and other charging devices.
In most cases lithium batteries can be a direct replacement to AGM batteries. Some chargers and controllers might need a different mode but in almost all cases the reconfiguration to lithium is something that can be done with minimal disruption to existing systems.
Read the full article here: