Lithium-ion battery

In off-grid solar technology batteries are the main source of reserved energy after it is been charged by the solar panels.In solar technology there are different types of batteries  available like Lead-acid batteries , or Lithium-ion batteries or Sodium Nickel Chloride or Flow batteries.In this section we are going to learn lithium-ion batteries.


A lithium-ion battery or Li-ion battery (abbreviated as LIB) is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. Li-ion batteries use an intercalated lithium compound as one electrode material, compared to the metallic lithium used in a non-rechargeable lithium battery. The electrolyte, which allows for ionic movement, and the two electrodes are the constituent components of a lithium-ion battery cell.


For many years, nickel-cadmium had been the only suitable battery for portable equipment from wireless communications to mobile computing. Nickel-metal-hydride and lithium-ion emerged In the early 1990s, fighting nose-to-nose to gain customer's acceptance. Today, lithium-ion is the fastest growing and most promising battery chemistry.




Lithium-ion (or Li-ion) batteries are the type of batteries you get in your Phone and laptop. They are also the type of battery that is inside the Tesla Powerwall.


In fact, Tesla simply connect thousands of AA sized Lithium-ion cells together and assemble them into a liquid-cooled battery pack, wrapped in a strong metal enclosure, which in turn is wrapped in their hallmark fancy plastic shield.There are many more companies coming to market with Li-ion battery packs as we speak. This technology has a very good chance of becoming the most popular home battery technology over the next few years.

Electro-Chemistry :


The reactants in the electrochemical reactions in a lithium-ion battery are the negative and positive electrodes and the electrolyte providing a conductive medium for lithium ions to move between the electrodes. Electrical energy flows out from or in to the battery when electrons flow through an external circuit during discharge or charge, respectively.







Both electrodes allow lithium ions to move in and out of their structures with a process called insertion or extraction , respectively. During discharge, the (positive) lithium ions move from the negative electrode usually graphite to the positive electrode (forming a lithium compound) through the electrolyte while the electrons flow through the external circuit in the same direction. When the cell is charging,the reverse occurs with the lithium ions and electrons moved back into the negative electrode in a net higher energy state. The following equations exemplify the chemistry.




The full reaction (left: charged, right: discharged) being

During discharge, lithium ions (Li+) carry the current within the battery from the negative to the positive electrode, through the non-aqueous electrolyte and separator diaphragm.During charging, an external electrical power source (the charging circuit) applies an over-voltage (a higher voltage than the battery produces, of the same polarity), forcing a charging current to flow within the battery from the positive to the negative electrode, i.e. in the reverse direction of a discharge current under normal conditions. The lithium ions then migrate from the positive to the negative electrode, where they become embedded in the porous electrode material in a process known as intercalation.




The increasing demand for batteries has led vendors and academics to focus on improving the energy density, operating temperature,safety, durability, charging time, output power, and cost of lithium ion battery technology. The following materials have been used in commercially available cells. Research into other materials continues.

Distinguishing between different types of lithium-ion batteries:

There are two core lithium-ion battery technologies: NMC (Nickle Manganese Cobalt) and LiFePO (Lithium Iron Phosphate)NMC battery technology, with its high energy density, is well suited to electric vehicles, whereas LiFePO technology is better suited to residential storage applications.The Tesla Powerwall 2, as well as the LG Chem RESU, uses NMC technology, and those companies will argue vigorously that NMC is the best bet for your home.Brands such as Simpliphi and DCS use LiFePO technology, and like to point out that LiFePO is inherently safer because it is harder to make them go into thermal runaway, otherwise known as exploding.You may ask why companies would use NMC technology for residential storage.The short answer is - because their factories (like Tesla's Gigafactory) are already cranking out massive amounts of NMC lithium-ion batteries for electric vehicles, so they figure they may as well use them in a residential battery as well.NMC batteries are also, for now, cheaper to produce than LiFePO batteries. This may factor into why some companies favor NMC technology over LiFePO.

Advantages :

• High energy density - potential for yet higher capacities.

• Does not need prolonged priming when new. One regular charge is all that's needed.

• Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.

• Low Maintenance - no periodic discharge is needed; there is no memory.

• Specialty cells can provide very high current to applications such as power tools.

Disadvantages : 

• Requires protection circuit to maintain voltage and current within safe limits.

• Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.

• Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.

• Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.

• Not fully mature - metals and chemicals are changing on a continuing basis.

This is mainly due to the fact that lithium-ion batteries can be discharged deeper and have a longer lifetime than lead-acid batteries. They will give you around 4,000 - 6,000 cycles at 80% discharge - so they will have a lifespan of 13-18 years.Their main drawback, at least at the moment, is that they are about 50% more expensive than lead-acid batteries for the same amount of storage. This is expected to change rapidly over the next 5 years, however, as mass-production of lithium-ion batteries (like at Tesla's battery factory, the Gigafactory) significantly reduces the cost of lithium-ion storage.

Hope you enjoyed this post (JajaKallahu Khair)