High technology applications require working in precisely controlled environmental conditions. Lithium battery application is fast growing across diversified industries like Electronics, Automotive, Electric Vehicles (EV), Energy Storage, Solar, Telecom, Power, Defence, Space/Satellite, Healthcare etc.
The Lithium ions are the carrier that creates the battery power but Lithium is only component of a complex battery system. A Lithium Ion battery is made up of four primary components. The cathode, which defines the battery’s capacity and voltage and is the source of the lithium ions. The anode allows electric current to flow through an external circuit, and when the battery is charged, lithium ions are stored in the anode.
The electrolyte, which consists of salts, solvents, and additives, serves as a pathway for lithium ions between the cathode and anode. Finally, the separator is the last component, which is a physical barrier that separates the cathode and anode.
In 1991, a standard battery was of 80Wh/Kg, by 2018 it had increased to 250Wh/kg, and expected to reach 400 – 600 Wh/kg with new innovations of high energy density, fast production processes and fast charge, even wireless charging.
These new innovations involve different types of packaging, physics and chemistries. However, these new LI battery technologies also involve micro-miniaturisation and this leads to the need for Dry Cleanrooms, to minimise defects and maximise yields, reliability and safety.
There are 3 types of battery technologies, Cylindrical, Prismatic and Pouch, with Pouch applications expected to grow to dominate the market in future.
The technology of cylindrical lithium batteries has been around for a long time, which means the pack consistency is high. The cost of the packs is also low, making them suitable for mass production. The cylindrical cell battery is particularly convenient to use for its various combinations and suitability for electric-powered vehicles like Tesla, for instance. However, cylindrical lithium-ion battery packs are heavy, with not the best space utilisation and may have already reached its limit in terms of performance and optimisation.
Prismatic cells are packaged in welded aluminium housings make optimal use of space by using the layered approach. These wrappings resemble a box of chewing gum or a small chocolate bar These cells were predominantly found in mobile phones with lithium-ion but are now being used in electric powertrains and energy storage systems.
The pouch cell battery pack makes the most efficient use of space and achieves a 90 to 95 percent packaging efficiency, the highest among battery packs. Eliminating the metal enclosure reduces weight but the cell needs some alternative support in the battery compartment.
The pouch cell offers a simple, flexible and lightweight solution to battery design. Exposure to high humidity and hot temperature can shorten service life. The electrodes and the solid electrolyte are usually stacked in layers or laminations and enclosed in a foil envelope. The solid electrolyte permits safer, leak-proof cells. The foil construction allows very thin and light weight cell designs suitable for high power applications but because of the lack of rigidity of the casing the cells are prone to swelling as the cell temperature rises and gas generation during charge and discharge cycles. Pouch cells are also vulnerable to external mechanical damage and battery pack designs should be designed to prevent such possibilities.
There are future battery technologies and alternative chemistries being developed. These include Solid State batteries, Sodium Ion and other chemistries, alternative electrodes; all of which will give higher power densities and capacities with increased range and rapid charging.
Other innovations will include hot swapable battery packs for flexibility in travel options.
