7th January 2022

The importance of a safe BMS in two and three-wheeler EVs

Electric Vehicles that are primarily run by Lithium-ion batteries are in demand all over the world. As per Allied Market Research, the global electric vehicle is expected to grow at a CAGR of 22.6% between 2020 to 2027.

As EVs run on batteries, they don’t emit CO2 or GHG gases unlike petrol or diesel-driven vehicles. They cause less or no pollution which is beneficial to the environment. The greener aspect of these modern vehicles is something that can’t be ignored. However, these modern vehicles also brought a challenge along with them. There are recent incidents reported of many electric vehicles catching fire. 

But why is this happening? The reason lies in the complexity of the fuel of EVs –  the battery packs. A single error in the wiring inside the EVs can cause thermal runaway of cells ultimately resulting in fire and or even a blast.

However, there’s also another component of an EV that plays an important role in its working – the Battery Management System (BMS). A good quality battery along with an efficient BMS ensures the smooth and safe operation of an EV.

What is a Battery Management System (BMS)?

A Battery Management System (BMS) is a technology that is integrated into battery packs for battery monitoring and management. The primary goal of a BMS is not only to ensure the safety of the EVs but also to improve the overall battery performance for its prolonged usage and long life.

Since the chemistry inside a battery is quite complex, it is prone to undesirable conditions like overheating, over-voltage or over-current, deep discharge, and mechanical stresses. To prevent these conditions, a battery must operate within its safe operational window, thereby requiring a BMS.  

Functions of a Battery Management System (BMS) inside EVs

There is no set rule or fixed criteria to develop a BMS for an EV, as it depends on a variety of factors like the battery pack size, cost, the desired application, battery lifespan, and other factors.

Nonetheless, a safe and high-quality battery management system is essential and it performs the following functions inside a 2 or 3 wheeler EV:


1. Indicating State of Charge (SOC)

The State of Charge (SOC) in an EV is like the fuel indicator in common vehicles. A driver of an electric vehicle also will want to know how much further it can drive with his last charge. 

So, similar to our mobile phone or laptop battery percentage, the SOC of an EV tells how much capacity a battery is left to utilize. Apart from this, SOC calculation also assists in cell balancing (more on this ahead).

However, there also comes a limitation with SOCs. It doesn’t indicate the overall health of a battery. Over the long period of usage, a cell gets eroded and its capacity decreases. Even if a battery shows 100% SOC, its actual or real-world capacity is likely less than this. So, for determining the overall health of a battery pack, we have another indicator called State of Health (SOH).

2. Determining State of Health (SOH)

The SOH tells us about the long-term capacity of a battery pack and it’s measured against the time when the battery was fresh or newly installed. For this, the BMS keeps the record of the health status of the entire lifecycle of a battery. 

For the SOH estimation, the BMS takes into account various factors such as the charge acceptance at the moment, internal resistance, voltage, self-discharge, and other parameters.

3. Maintaining Safe Operating Area (SOA)

As battery packs are susceptible to adverse environmental conditions, they must operate within their operating limits known as Safe Operating Area (SOA).

The cells inside an EV are designed to operate within certain limits or ratings with regards to parameters like current, voltages, and temperature. An intelligent and well-designed BMS will protect the battery pack from going outside the defined range.

It’s important to note that the battery capacity and its SOA get altered or degraded with time due to changes in chemical reactions. A high-quality BMS will also take this factor into consideration. 

4. Cell Balancing

Cell balancing is a process that equalizes the charge between all the cells inside a battery pack. 

The process of cell balancing is required because no two cells are identical or operate equally. One cell has a charging rate different from the other cell within the battery pack – even if they are manufactured by the same company and in the same batch. 

This phenomenon may result in deep discharging or overcharging which can degrade the cells and ultimately the entire battery pack. A BMS plays an important role here as it monitors the cells, calculates their SOC, and controls the charging of each cell to ensure each cell is charged evenly. 

5. Reporting operational feedbacks

A safe and efficient BMS not only manages the operations of a battery but also reports complete information regarding the battery’s operational status. It even provides necessary feedback to the end-user or the maintenance technician about unusual events or errors so that required action could be taken on time to avoid any major accident.

In conclusion

As a part of a fortunate incident, the demand for electric vehicles is increasing among the masses. Thanks to these modern vehicles, they don’t cause any pollution and help in contributing towards a greener earth. 

Looking at this opportunity, many EV players are coming entering the market. However, there also arrives a major challenge with EVs which is related to their fuel system. Several fire-catching incidents of EVs have been reported across the world. 

The fuel system of the EVs mainly comprises batteries and the Battery Management System (BMS) that comes along with it. So, good quality batteries with an efficient BMS are important to ensure the safety and smooth operation of EVs.

Finally, needless to say, an independent inspection of EVs and stringent regulation from the government are also important to ensure the complete safety of buyers.

ION Energy – India’s Most Reliable BMS for Electric Two & Three Wheelers

Electric 2 & 3 wheelers such as scooters and rickshaws have complex use-cases that require smarter management of their batteries. ION Energy’s automotive-grade battery management systems have been designed to meet the requirements of next-generation electric two and three-wheelers.

Learn how ION Energy can help you build a high-performing e-scooter/rickshaw battery pack with long-lasting battery life.


About ION Energy

ION Energy is an advanced battery management and intelligence platform. We’re focused on building technologies that improve the life and performance of lithium-ion batteries that power electric vehicles and energy storage systems.

Our customers typically choose ION Energy because of its reliability, transparency, commitment towards customer success, and innovative business models. OEMs and battery pack manufacturers across the globe choose ION’s integrated battery management solutions to continuously improve the life and performance of the battery.

Also read: Maxwell gets accredited with ISO 9001:2015 Certification


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