India’s electric vehicle (EV) enthusiasts are worried over several incidents involving two-wheelers bursting into flames since last month. Such incidents are a major cause of concern for stakeholders in the EV industry and their customers. Some have attributed these fires to a combination of the rising temperatures in our cities and the poor thermal management system of the EV battery. Yet, blaming the weather is wrong. There are many misconceptions such as the Indian summers and poor thermal management being the reason for the outbreaks of EV fires are not true.
Instead, we should prefer looking more closely at how a lithium-ion (Li-ion) battery is packed and designed. An EV comprising lithium-ion (Li-ion) cells requires a few hundred degrees Celsius before suffering a ‘thermal runaway incident’ and that causes EV fires. Extreme hot weather conditions and improper thermal management systems of the battery can negatively impact performance and shorten life, they do not cause fires. Several manufacturers of the Li-ion batteries ensure that they automatically switch off around 45-55 degrees Celsius. If these safety features aren’t built-in in the vehicle, it’s impossible for the ambient heat and the heat generated by batteries can cause a spike of a few hundred degrees Celsius.
These fires are a case of QC concern, perhaps something not taken into consideration in the design stage. It could be that weather patterns for different target geographies that were not considered, pack assembly process not being the most robust or simply limited testing not exposing chinks in the armor. One thing we have seen over the past one year is the booming demand and subsequent sales of EVs, especially 2-wheelers. We have also seen a scramble for securing battery cell supply chains given the global demand boom. That’s why OEMs look for alternatives in order to safeguard their production schedules. While most cells across makes offer similar output for a given specification band, QC can be a big variable.
Cell selection is a big factor in the whole battery pack design development, and variances in cells can translate to bigger variances in pack output. Thus, when we look at multiple cell supply chains, each one needs to be vetted as well as the first choice. Vetting a cell make and model requires exhaustive testing to ensure performance and safety under a wide range of conditions and as such is not a process that can be hastened.
In recent times, most of the battery fires are due to short circuits leading to uncontrolled current. In this condition, the cells heat themselves up beyond 100°C. Poor cell quality and shoddy battery design causes short circuits, and the lack of proper battery management system (BMS) is a condition in which cells are not managed properly with the right sensing and software technolgies. This rise in temperature affects life and performance of the battery, but it doesn’t cause EV fire. To catch a fire in a lithium-ion battery, it needs a few hundred degrees Celsius. Which is not possible through ambient heat or the heat generated by an operational battery.
There has to be a short circuit for the battery cell to hit that sort of temperature which causes fire. Many EVs that caught fire were using more temperature-sensitive battery chemistry called NMC. To use a more temperature-sensitive battery, at the battery pack level, there were no design measures taken to ensure that it’s thermally cooled properly. The fire suppressant materials were lacking in those vehicles because that may lead to additional costs, volume and weight requirements in the vehicle. Many OEMs cut corners just to reduce cost and ensure greater battery range and then launch these products without all of the right design choices.
The rapid scale up in EV and battery assembly that has happened over the past year. Manufacturing is an activity that requires capacity. Capacity build-up requires time. There are QC challenges that come up when manufacturing scale is increased, which also need time to sort out. It is not a process that can be hurried up, and certainly not as fast as it has happened in the last year or so. If not done right, manufacturing scale-up can be chaotic and can lead to QC nightmares. Both EV/battery assembly as well as the supporting vendor ecosystem is quite new to India and will take some time to establish QC norms. The rapid scale up of battery assembly facilities and component manufacturing/vendor development could be a reason why variance in quality would crop up.
OEMs being incentivized by the FAME subsidy rise to deliver larger capacity battery packs without changing the vehicle designs. Trying to stuff larger capacity in the same volume pressurizes pack designers to compromise on safety aspects of pack engineering. The increase in sheer numbers of vehicles sold before QC could have been stabilized is the major reason for these fires.
Measures to solve this problem – First off, the QC for battery pack assembly (and the localized component manufacturing) needs to be perfected. We need secure local supply chains for cells, ones that are made with Indian conditions in mind. The QC challenges of manufacturing come in for cell manufacturing, perhaps even more so. India has not seen LIB cell manufacturing yet, and is looking for a massive scale up with the PLI plans. The conventional LIB cell manufacturing process is extremely QC sensitive and even the smallest of slip-ups cause safety concerns. Cell manufacturing in India needs to happen as a well thought out exercise after fully understanding the process involved and its limits, lest we see an even bigger problem when locally manufactured cells enter the huge EV market. If the LIB cell design and manufacturing process itself can be reworked for Indian requirements, keeping in mind the impact of the process on the QC, it could be a fundamental solution to the fires in batteries. We need a proper temperature measurement system sensor built-in. When the battery cell is going above a certain temperature, the system either cuts off power, immobilises the vehicle and sends a message to the user that they need to take this vehicle to another place where if the vehicle caught fire, it doesn’t result in the loss of life and property.
We also required it on the charger side. Nowadays, many people use smart chargers to charge their EVs. There are high chances that these chargers can communicate with the battery pack, and get data on the temperature or the health of the battery. We need to work to build failsafe measures so that the charger can communicate that the battery temperature has become very hot and can’t be charged right now. There are many regulations related to the EV Industry that are also evolving, but industry always has a choice to stand ahead of it. All EV players should present temperature resilient certification and provide it to customers when they buy a new vehicle. We should build multiple third-party labs in India that can test these batteries at different temperatures be it high or low, operating conditions and provide OEMs with a temperature certificate.
In the age of viral internet media spread, misunderstandings can negatively affect the future of EVs, which is very beneficial for the nation. So, to avoid such incidents in the future, We need to indigenise our standards and values for Indian roads. The industry players themselves can take a call to get a third-party certification even if the regulator does not require it. With this note, I can only say that these kinds of mishaps and setbacks are part of the technology especially when we are moving toward modern technologies, and it would eventually lead to better solutions and safety systems being built into Electric vehicles.