Days after electric scooters made by Ola Electric and Okinawa Autotech caught fire, there has been concern about the use of lithium-powered batteries in the electric vehicles (EV), and whether they are reliable in handling internal pressures within the machines.
Last year, the American auto giant General Motors Co expanded the recall of its Chevrolet Bolt EVs due to a fire risk posed by pouch-type lithium-ion battery cells manufactured by LG in South Korea. The recall, which is a big one involving LG Chem’s battery company (LG Energy Solution), highlights the difficulties faced by battery manufacturers in developing a reliable product to power the EVs.
It is worth noting that Sony’s handheld video recorder was the first to use lithium-ion batteries, which were invented in the 1970s and marketed in 1991. Everything you see today is powered by batteries, from smartphones to electric cars to the International Space Station, making battery safety even more critical.
Tesla debuted the Roadster in 2008, making it the first automaker to market a battery-powered EV.
However, the global lithium-ion (Li-ion) battery industry is estimated to reach $100.4 billion by 2025, with the automotive market accounting for more than half of this.
In the case of how this battery works, electrodes, electrolyte and separator are the three main components of cells, which come in a variety of shapes and sizes. Lithium is stored in electrodes. The lithium ions are carried between the electrodes by the electrolyte. The separator prevents the positive and negative electrodes from coming into contact.
When lithium ions travel from the negative electrode (anode) to the positive electrode (cathode), energy is discharged from the battery cell in the form of electricity. When the cell is charging, those ions travel from the cathode to the anode in the reverse way.
Lithium-ion batteries, whether in automobiles or electronic devices, can catch fire if they have been badly made or damaged, or if the software that controls the battery has been poorly designed.
The use of organic liquid electrolytes in lithium-ion batteries in electric cars is a serious flaw since they are volatile and combustible at high temperatures. Chemical leakage can also be caused by an external force, such as a crash.
So it is advised that before being sold, cells should be subjected to stringent quality-control tests and certification.
Kim Pil-soo, an automotive engineering professor at Daelim University earlier told Reuters: “For EV fires, it has been always very difficult to pinpoint the exact root cause of the fire because it is extremely difficult to ‘re-enact’ the fire incident with the same conditions.”
Although all three varieties of lithium-ion batteries now used in electric automobiles — cylindrical, prismatic, and pouch-type — perform similarly, each has advantages and disadvantages.
Hard materials are used to encase cylindrical and prismatic batteries. Pouch-types are protected by thin metal bags and use sealed flexible foils.
The technology utilised in cylindrical batteries is outdated, but it consistently produces reliable results. These cells are resistant to deformation under high internal pressure.
They are also less expensive, which makes them perfect for mass production. However, they are heavier, and the structure of the cells prevents them from being packed as densely as other battery types.
Prismatic batteries are considered safer and lighter than cylindrical cells and, because they are rectangular, can be more densely packed. They optimise space better than cylindrical cells, but are typically more expensive and have a shorter life cycle. They can also swell.
Compared with cylindrical and prismatic cells, pouch-type battery cells allow for lighter and thinner cell fabrication and design flexibility for different capacities and space requirements for different vehicle models.
However, they are vulnerable to swelling, and are more vulnerable in crashes, posing a greater fire risk.
In simple words, lithium-ion batteries are naturally flammable and are particularly sensitive to high temperatures. Heat causes these battery packs to degrade much faster than they would otherwise. If a lithium-ion battery pack fails, it will erupt in flames, causing extensive damage. This necessitates rapid battery safety procedures and standards.
Companies like China’s BYD Co make electric vehicle battery cells with lithium iron phosphate cathodes, which are less prone to catching fire but can’t store as much energy as ordinary nickel cobalt manganese cathodes.
Others like GM are experimenting with new chemistries, including nickel-cobalt-manganese-aluminum (NCMA) technology, which uses less cobalt and hence makes the cells more stable and less expensive.
Last month, CATL, a Chinese battery manufacturer, announced a sodium-ion battery that is free of lithium, cobalt, and nickel.
A number of companies are working on solid-state electrolytes for battery cells, which could reduce overheating and fire concerns but require three to five years to commercialise.
Furthermore, by making Lithium-Ion batteries ‘smart’, they can be made safer. One can not only diagnose but also forecast aberrant battery usage or performance by incorporating a layer of intelligence into the batteries. This will allow us to take prompt action, avoid system damage, and assure battery safety.