Why do Electric Vehicles catch on fire in India?

Electric Vehicle sales have seen a month-on-month increase of over 400%. From just selling 6000 units in Feb of 2021 the industry had a monthly sale of 32,416 units in Feb of 2022. 

 

The surging fuel prices and the increase in the range of Electric Vehicles are the primary reasons for this exponential climb in EV sales. 

 

The two-wheeler EV market in India is an ever-evolving one with traditional brands like Hero, TVS, and Bajaj competing against start-ups like Ather and Ola Electric.

 

EVs have enjoyed an increase in growth thanks to a multitude of factors. However, the recent incidents of battery packs exploding and causing fatal injuries to users have thrown the spotlight on EVs. Laying bare to the general public the internal circuitries that have gone wrong. 

 

What causes a Battery to explode? 

A battery is a cell that has positive and negative terminals. Current is generated when electrons move from one end to the other. A battery in the Electric Vehicle is an arrangement of thousands of these cells, first in series and then in parallel. These are then connected to the motor which then powers the vehicle.

 

These cells have an individual voltage of 3.6V. The charging and discharging of the battery ensure that the voltage and charge difference in each cell remains the same. Electric Vehicle batteries are designed to reduce cell overcharging. The cell balance should be maintained to ensure that the Lithium-ion cells do not explode.  

 

The process of charging and discharging is an exothermic process generating heat in the system. But, batteries operate within a temperature range of -30*C and 60*C. If the temperature rises above or below this specified temperature, the battery will stop functioning. 

 

The rapid rise in temperature can increase internal chemical reactions which can then further raise the temperature of the battery eventually leading to the battery exploding in a process called thermal runaway. 

 

What prevents an EV battery explosion?

The Battery Management System ensures that the battery does not compromise the integrity of the EV system. While charging the battery the BMS along with the onboard charger maintains the charging protocol. The charging of a battery occurs in three phases. The first phase or the initial cc charging phase followed by the constant voltage charging phase and the fine control charging phase.

 

To improve the life and range of the battery, the cells of the battery have to be equally charged or discharged, a function which is carried out by the BMS. The BMS monitors the SOH (state of health) and the SOC (state of charge) of the battery. It provides valuable feedback to the driver about the life and range of the battery. 

 

Most 4-wheelers Electric Vehicles manage their temperature through a process called liquid cooling. In this method, a coolant (glycol in the case of Tesla) runs through the battery pack inside specially designed pipes. This pipe is then connected to a radiator that transfers the heat from the coolant to the atmosphere. 

 

The battery management system is responsible for efficiently running the liquid through the cooling pipes; BMS failure can be due to many reasons. One of the possible reasons for the battery explosions of leading OEMs can be attributed to the BMS not being calibrated for Indian conditions. 

 

Reasons why EV batteries fail in India

India has a huge unorganized three-wheeler EV sector. Cycle-rickshaws or manually driven rickshaws are converted using Lithium-ion based batteries. The quality of the cells used in these batteries is poor and is often saddled with bad BMS systems. These batteries have an average power of 1kWh and are primarily used for short-distance freight hauling. With no adequate management of the batteries, these vehicles end up catching fire and cause hazardous injuries to the user.

 

The production of lithium batteries used in EVs is concentrated in the hands of 5 manufacturers, worldwide. Two of them are based in China, which holds a substantial reserve of Lithium. It is a finite resource that is found in small pockets in the world, currently, it is being mined in Australia, China, Chile, Argentina, and Bolivia.  

 

There is a lack of proper quality inspections for all the battery packs that are being used in India. The low regulation from the Indian government has led to substandard battery cells entering the market. 

 

Importing components which are designed for cold environment conditions and using them in India’s hot conditions. The BMS could’ve been configured to work at a temperature that is usually expected during summer, which due to global warming, has shot up against previous years.

 

Steps to prevent Battery explosions of EV vehicles?

• The whole market has to be regulated. Every part of the EV sector from the battery to the sensors used in the BMS and to the coolants used should be tested. Every EV that is launched in the Indian market should adhere to the AIS 156 standards. Currently, the industry follows the AIS-048 standard which was designed for lead-acid batteries. Proper implementation and adherence to the AIS-156 standard will see a decrease in fatal incidences. 

 

• Skill-Lync’s curriculum handles product development covering all the safety measures as specified by ISO 26262. various failure mode analysis, validation strategies, that are needed for safe operations of the product.

 

• There needs to be a structural change in the design of battery packs. The battery packs have to go through various iterations of safety checks and adhere to industry guidelines. To achieve this there needs to be a clear line of communication between the safety engineers and management.

 

• When importing batteries, firms often use substandard materials to cut costs and reduce the price of their EVs.  The Indian Government needs to impose stringent requirements, like the ones followed in Denmark, The Netherlands, or Norway, to ensure that batteries do not catch fire at the first sign of additional stress.

 

The Electric Vehicle market in India is under-regulated and has seen many new Original Equipment Manufacturers begin production. These new entrants have insufficient experience in designing and deploying automobiles. The government regulations have to be stringent to ensure automotive passenger safety. These regulations have to be strictly enforced. 

 

The recent spate of battery explosions in Electric Vehicles has thrown light on the severe lack of rules and regulations in the EV marketplace. The Government of India has started to clamp down on the quality of battery cells that are being imported into India.

With stringent efforts, the Electric Vehicle sector in India is sure to experience a positive upswing and achieve the targets set by the Government of India. 

 

Written with help and inputs from Skill-Lync’s in-house experts on Electric Vehicles.