The growing trend of electric vehicles has gotten a black eye these days because of the recent battery fires. Although no one was injured, the incidents have raised concerns about the safety of electric vehicles powered by lithium-ion batteries.
There are many unscrupulous manufacturers in the battery industry today. They claim incredible capacities based on poor formulas, and some forgo protection circuitry to save money. But the main thing everyone needs to be focused on is the chemistry as per the applications.

The chemistry behind lithium-ion batteries is complicated, but basically, the choice of cathode material for any application is of particular significance. The material for today’s commercial market has lithium-ion only with the combination of other materials like Ferrous, Cobalt, Nickel, and Manganese or Aluminum. But every Material has different characteristics as depending upon the multiple factors type and the ratio of metal ions- Nickel (Ni) has a high capacity, manganese and cobalt has high safety, and Aluminum increase the power of the battery. Therefore, the choice of material depends on the applications. There are 5 main reasons for a battery pack explosion.
Causes:

1) Manufacturing Defect 
During lithium-ion cell/battery production, manufacturers should keep a close eye on the cleanliness of the area as nanoparticle sized impurities can increase impedance and damage the cell. However, a separator or ultra-thin membrane that only allows the movement of ions within the cell is of good quality, because if a crack or damage occurs, it can cause a short circuit in a cell.

2) Designing, Assembling, and Thermal Management Flaws
Several EV companies have requirements for a sleek and elegant design for their high-range, high-performance vehicles.  For this reason, manufacturers should design the high-capacity battery pack in a compact form with a smaller body. 
But all these reasons can lead to serious thermal runaway problems due to the lack of proper thermal management and cooling vents in a battery and also create a short circuit between electrode and separator.

3) Charger Issues
As every lithium-ion battery pack has a unique chemistry, design and capacity through which the charging and discharging phenomenon will change. There are three modes for charging the Li-ion battery: constant current, balance and constant voltage. Also, chargers used for these battery packs have properly built-in protection to stop and start charging. Because if we overcharge and deeply discharge the battery, it will cause excessive heat and also shorten the battery life.

4) Using Low Quality of Components
The competition among lithium-ion battery manufacturers is increasing day by day. Therefore, each manufacturer reduces the price of the battery pack while reducing costs or using poor quality electronic components in BMS and chargers, but this can directly increase the risk of failures.
Because BMS and chargers are the main components for battery safety and performance analysis. Therefore, for high-capacity batteries, the manufacturer should adopt an intelligent BMS to detect failure earlier before the explosion.

5) Mishandling of Li-ion Battery and Improper Usage 
This cause is mainly for the customers because they need to know how to use the lithium-ion battery pack. What are the pros and cons of the lithium-ion battery? 
The extremely important point is to keep these batteries in a shaded area, away from heat sources or fire that can cause a temperature rise or an explosion. Secondly, never accidentally or intentionally penetrate a sharp object into a battery, as this can cause a short circuit in a lithium-ion battery pack.
For this reason, we always advise customers to buy a battery from authorized manufacturers, because without proper testing and grading, the battery is always dangerous for the users.

Precautions:

1. Proper Thermal Management (Runaway) has to do with a different thermally conductive material and thermal sensors for thermal measurement.
   Proper pressure-sensitive venting Holes are provided for removing the overpressure (hot explosion) in the battery.
   PTC switch that prevents the battery from over-heating.
   Proper Cell balancing and charging need to be done with the help of the Battery Management System (BMS).
   It’s mandatory to connect the BMS with the battery pack without BMS, a Lithium-ion battery is not recommended to any of the customers.

Author Details:

Name: Dr. Snigdha Sharma
Education: Ph.D. (DTU, Delhi) + M.Tech + B.Tech (GBU, Delhi-NCR)
Work: R & D Manager at Solmitra Power & Steel Pvt Ltd