Fusing a Proper BMS?

In the last few months, the number of EVs catching fire has reinstated the nascent technology. This has not just turned heads toward the future of EVs but has nudged to reevaluate newer safer mechanics and integrated technologies in the new automotive. From industry leaders to the government authorities, everyone is emphasizing the need of adopting electric vehicles. To some extent, people also have started moving toward electric vehicles. For operating such vehicles, few things are necessary and the battery is the most important or can be said the central unit of these automobiles. For proper battery operations, there is a sensor available that monitors and regulates internal operational parameters, i.e. temperature, voltage, and current during charging and discharging of the battery. In a technical language, the BMS monitors the SoC (State of Charge) and SoH (State of Health) of the battery to improve safety and performance. Research from Verified Market Research says, the automotive battery management system market size was valued at USD 4.05 Billion in 2020 and is projected to reach USD 13.52 Billion by 2028, growing at a CAGR of 16.27% from 2021 to 2028. In our June issue cover story, Sushant Kumar, Founder & Managing Director, AMO Electric Bikes | Ranjita Ravi and Dr. Prajwal Sabnis, Co-Founders, Orxa Energies | Vijayalayan R, Manager- Automotive Industry, MathWorks India | Shreshth Mishra, Co-Founder, Simple Energy | Naveen Dachuri, CTO and Co-Founder, Yulu extensively elaborates about BMS and the future towards safer EVs in India.

Battery Management System (BMS) Transforming the Industry

Battery management systems are very critical for the continuing health of battery packs and even more critical in higher power and higher capacity battery packs. It is required for better coordination with vehicle electronic systems and control systems. BMS is one of the most important segments of battery pack engineering. It has to match the requirements of the vehicle (vehicle performance, power and current ratings, performance throughout the endurance, and others). At Orxa Energies, we spend quite a lot of time developing different kinds of batteries for Automotive, Aerospace, Defense, Leisure, and other high-performance systems. One thing we keep in mind is that there are multiple things going into a battery pack – the cells, how the cells are put together (mechanical design, electrical design, electronics design), how the electricity is being taken out of the cells, and at what rate or how quickly you are pulling the current out of the cells (current rates, power, etc). So, these battery management systems are built with multiple levels of safety, including a communication system as well
to interact with the vehicles, says Ranjita & Prajwal.

Battery as a storage unit of energy plays a significant role in taking the electric vehicle industry to another level, but recent mishaps in the vehicles are raising many questions. LI battery is nothing but a series of LI cells and Battery management system helps in maintaining the health of each cell by displaying the accurate percentage of cell’s capacity, and remaining charging cycles of the cell and hence gives a longer life to the battery. It also helps the original equipment manufacturer (OEM) to record the crucial data of vehicle. This accumulated data universe helps the OEM to pin point the problem, to analyse if there is a trend in the data, to figure out issues and finally to seek the solution and improve the product, explains Sushant.

Vijayalayan says, the battery packs and battery technology design enable the automotive companies to produce more efficient electric vehicles. The batteries require accurate real-time monitoring and control to avoid overcharge or over discharge conditions that shorten their lifespan and affect safety. The parameters that are critical for the functioning of the battery packs and the electric vehicles are State of Charge (SoC), State of Health (SoH) and temperature. For example, State of charge (SOC) is a relative measure of the amount of energy stored in a battery, defined as the ratio between the amount of charge extractable from the cell at a specific point in time and the total capacity. Accurate state-of-charge estimation is important because battery management systems (BMSs) use the SOC estimate to inform the user of the expected usage until the next recharge, keep the battery within the safe operating window, implement control strategies, and ultimately improve battery life. Whereas Shreshth feels, BMS plays a very important role in optimising the performance of the battery pack, making it safer, smarter and more efficient. It balances each cell and ensures proper charge and discharge from the battery pack to ensure the safety of the battery pack and also optimum performance.

Naveen explains, in the fast growing and technologically fast-moving Electric Vehicle (EV) industry, BMS is of significant importance to know, interpret and maintain the health and functionality of the cells and battery packs. Our BMS system helps us in regulation and preventive maintenance of the batteries charge-discharge process, heat management, data communication, and safety management. BMS, and the subsequent development in its technologies has made it easier, and more efficient for the automotive industry to track various parameters of the cells and battery packs like voltage, current, temperature, wear and tear of our battery packs, etc. Our Vehicles, Batteries, and Charging units are continuously communicating with our cloud systems, giving us real-time data on the state, status, and health of our batteries.

BMS- A Safety Concern

Safety has become a major concern in Electric vehicles as fire incidents of EVs are lately reported. Recently, an electric scooter caught fire in Hosur in Tamil Nadu’s Krishnagiri district. The owner, a supervisor at a private firm in Bengaluru, however had a providential escape. A father and his daughter died due to suffocation in Vellore district in March due to the smoke caused by the explosion of the electric bike while being charged. An electric two-wheeler caught fire in Manapparai in Tiruchirappalli district, later. In April, a man died when the detachable battery of the electric scooter kept for charging exploded in his house in Telangana. Such kinds of issues have made every EV owner bit afraid about safety. One side government authorities and industry leaders are trying to get EV adopted in the country and the other side fire catching story has become a daily update of the day.

Safety being the biggest concern all across the industry, Every OEM needs to maintain international standards of quality not only at the product development stage but also at the time of mass production, mentions Sushant.

As we can see the mushrooming of LI Battery manufacturers in the country, to standardised the quality Government needs to put stringent manufacturing norms for all the manufacturers. Consumers should be educated on how to maintain their electric Vehicle specifically the battery. One should always use genuine accessories, using spurious / unauthorised accessories may become a reason of such unpleasant events. Customers as well as OEMs needs to control the temptation of having high-speed vehicle. This area requires research and development and we as an OEM needs to understand our responsibility and provide faster charging and high-speed options only in the recommended range, he adds.

While sharing their own experience, Ranjita & Prajwal explains, one thing that we would want to call out is that it’s a misconception that the summer in India is responsible for causing such incidents. A battery pack would have to go to 100 plus degrees Celsius for such a situation to occur. At Orxa Energies, we tested out the vehicles in extreme weather conditions during the Electric Bharatmala ride, where for example the Mantis was riding for more than 470 Kms a day or they were riding for 2000 Kms a week in a heatwave through places like Punjab, Rajasthan, Haryana, and Gujarat. And the remarkable part is we did about 2000 km when the temperature was above 40-44 degrees Celsius. We were curious to know how well the EV could withstand freezing cold now that we had tried riding through heat waves. So our riders did a week between Dehradun, Manali, Srinagar, and Jammu where the temperature dropped to -2 degrees C.

Li-ion battery technology is the most used battery technology in the development of batteries that run electric vehicles. This is a sophisticated technology; hence proper care is necessary in manufacturing and operations. The Li-ion battery does store energy in small packages. If, due to some adverse event, this energy is released without proper control, it could cause a dangerous condition known as thermal runaway, mentions Vijayalayan.

The battery management system is responsible for safe operation, performance, and battery life under diverse charge-discharge and environmental conditions. When designing a BMS, engineers develop feedback and supervisory control that monitors cell voltage and temperature, estimates state-of-charge and state-of-health, and limits power input and output for thermal and overcharge protection. With the increase in software content in today’s electric vehicles, companies need to focus on migrating their existing embedded software development process to be in compliant with objectives of functional safety standard such as ISO 26262, he adds.

He further explains, in summary, with the need for efficiency improvement and meeting the shrinking timelines, there is a big need for virtualization of the Electric Vehicle development and testing using the simulation-based approach. Using simulation, engineers can assemble all the key software components that have to work together for a specific application and study how well the integrated system meets their requirements. Virtual Vehicle also enables engineers to assess functional behaviour and gain insight while reducing time spent in the vehicle, especially when the test cases have any hazardous scenarios.

In the automotive industry, Safety should be taken care of from the design stage and followed through the whole lifecycle of the battery and vehicle. Cells, BMS, Thermal management, redundant safety systems, Battery pack assembly process plays an important role in the safety of battery packs. Data from the BMS should be monitored regularly to identify the symptoms of battery failure. Vehicle and charging systems should be designed accordingly. Last but not least, all the processes for incoming checks, deployment checks, periodic maintenance checks, Degraded and faulty battery checks should be imbibed for proper maintenance and for enhanced safety, says Naveen.

Safety should be of the utmost importance for automotive players. Some of the ways it can be resolved are proper battery packaging, choosing the right quality of cells, proper thermal management, usage of a good quality BMS with proper cell balancing, short circuit protection and other features, clarifies Shreshth.

Battery Swapping Policy

The Battery Swapping Policy show the intent of the policymakers toward pushing new business models in EVs and helping the ecosystem evolve. Since EVs and battery packs are nascent technologies, and there is rapid innovation happening in this space, allowing multiple operation models and market-driven innovation is critical for both cost improvements as well as for consumers’ access to the latest technologies.

Ranjita & Prajwal says, we strongly believe that the ability to innovate business models, such as the novel financing models will be crucial for the success of any battery swapping ecosystem. This is something we, at Orxa, have worked with our financing partners as well. For this to be successful, vehicle makers and battery makers will have to work closely to ensure the battery packs work well with the vehicle parameters. What is interesting here is that distinctions are being drawn between a ‘Charging station’ and a ‘Swapping station’ – meaning that in certain situations, large, centralized warehouses for charging, with small ‘Kirana’ swap stations are also a possibility. This is a positive step. There are many smaller locations that may not have the financial or other means to obtain appropriate permissions and/or additional permits needed from DISCOMs to function as charging stations. With this policy, these can still earn revenues from being a swap station. It can help level the field for these two players, they clarifies.

Battery swapping policy will definitely induce the confidence of travelling longer distances in the users. This is surely a huge step towards 100% electrification in auto sector. But to successfully achieve the desired results from this move, bigger players need to work on developing the infrastructure and standardised the battery specs so that the swapping happens smoothly. I believe battery policy will bring revolution in this industry. Busses, cars & three-wheeler would be the most beneficial segments. Two-wheeler will also enjoy the benefits of
this policy, feels Sushant.

Vijayalayan points out few technical hurdles and challenges that need to be addressed before the successful implementation of battery swapping technology. The draft policy currently under review and feedback phase (at the time of this interview) has captured them as shown below:

• Batteries must be BMS enabled – to enable monitoring, data analysis and safety.
• BMS of the battery must be self-certified and open for testing to check its compatibility with various systems, and capability to meet safety requirements.
• Batteries must be IoT enabled to allow for safety and security monitoring Unique identification numbers must be assigned at the manufacturing stage – to help traceability.
• Testing and certification – Batteries shall be tested and certified as per AIS 156 (2020) and AIS 038 Rev 2 (2020) standards
• Standards for communication between battery & vehicle controller, battery & charger, battery & energy operator server to be defined by BIS

Battery being a very critical component of the vehicle is also a safety hazard, we have seen problems coming up with battery packs and a single battery pack being used by multiple people becomes a problem because you don’t know how every individual uses that and at the same time buying a new battery pack and swapping it with another battery pack which might be a year-old or more. The uncertainty of the performance increases significantly, says Shreshth.

Naveen supports the EV battery swapping policy, he says;

• Battery Swapping solves two significant problems faced by EV users range anxiety and downtime of vehicles.
• Being India’s largest Shared Mobility company, we have created a dense and well-connected
  network of battery swapping stations called Max Network.
• With the proposed Battery Swapping policy, it will enable shared EV mobility players to create the necessary Battery swapping infrastructure, thus increasing the scope of EV usage by delivery workers, apart from shared mobility users.
• This swapping network will also reduce the cost of EV ownership, and function as an accelerator for EV infrastructure development, and adoption by personal EV mobility users.
• The policy will also help in recognizing Battery-as-a-Service players to come under the ambit of BaaS related specific subsidies, incentives and financing options by the government.
• Standardization is another topic that we closely discuss. Our personal thoughts on the matter is that stringent regulations around battery standards stifle innovation. We believe that for a nascent industry like EV, different players have to be allowed to innovate, and decide the industry standards for themselves with time.

Innovation in BMS Sector

There have been pretty significant leaps in measurement accuracy. This we would say has given rise to a better than before synchronicity in measurements which helps us estimate more precisely for both SoC as well as SoH calculations. Another notable improvement would probably be the advancement in sensor applications especially when it comes to temperature measurements. This can drive better control of the vehicular systems. Lastly, the refined communication protocols have been a major breakthrough if you consider it from an engineering
point of view, feels Ranjita & Prajwal.

Battery Management System (BMS) not only helps in tracking the vehicle records but also helps in controlling the short circuits in case of any such situation, regulating the performance of the vehicle etc. At AMO Electric Bikes we use Smart Battery Management System and ensure the safety of each vehicle. When it comes to innovation in any field, we all know sky is the limit. In collaboration with our supplier, we are working on marring the IOT technology to BMS technology. I am a believer of the quote stated by Thomas A Edison “There’s a way to do it better- Find it.” We at AMO Mobility Solutions keep working on betterment of the product and procuring best of the technology and we will constantly work towards our vision on converting E-Mobility in to Mass Mobility, shares Sushant.

According to Vijayalayan, the following are the innovations in BMS Sector;

• A battery is probably the costliest part of an EV, contributing to 25-40% of the total cost. So, you can expect continuous innovations by OEMs and other related players to bring the cost down.
• Some OEMs believe that solid-state batteries offer higher energy density than that of conventional lithium-ion batteries. There is research in this field as this could shorten the charging time and lower costs
• Battery state of charge (SOC) is a critical signal for a battery management system (BMS). Yet, it cannot be directly measured. Virtual sensor modeling can help in situations where the signal of interest cannot be measured or when a physical sensor adds too much cost and complexity to the design. Deep learning and machine learning techniques can be used as alternatives or supplements to Kalman filters and other well-known virtual sensing techniques. These AI-based virtual sensor models must integrate with other parts of the embedded system.
• With the need for remote monitoring of performance of a battery, we would be seeing more technologies like IoT being leveraged to make them happen.
• With the need for better calibration increasing, companies are set to leverage cloud technologies to help frequent calibrations that will optimize the SoC and SoH of the battery.
• To make most of the above happen, you will see researchers and other stakeholders using digital twin models of batteries to help accelerate development time and reduce costs.

Some innovations driving the BMS are higher efficiency, cloud connectivity, adaptive BMS & battery packs, short circuit, under-voltage, overvoltage protection units, and optimising advanced connectivity features, says Shreshth.

BMS is not just for keeping the battery in a safe operating area, it also helps in extending the life of the battery packs, mentions Naveen. He says the recent innovations are more focused on;

• AI in the BMS: it helps to analyze all the sensor information locally and predict a failure of the battery, degradation of the battery etc. It also helps in extending the range of the battery. There are much other analytics that is open to being explored now because of the above features.
• Data storing and Diagnostics: till now there was a basic level of diagnostics and data logging. Now, along with GPS and GSM, detailed and deeper diagnostics can be achieved and data logging helps in recreating the issues faced on the field.
• Dynamically configurable parameters: The parameters of Current, Voltage and temperature are dynamically changed to enhance range or decrease charging time. This is made possible by adding more sensors and accurate measuring by the sensors.

Conclusion

Any electric vehicle requires a sensor to operate and the Battery management systems (BMS) are the “brains” responsible for the efficiency, safety, and longevity of lithium-ion batteries. As the firing cases are increasing and EV sectors are facing major losses, we need to have a proper R&D done battery management system. According to a news portal, the consumer affairs ministry is likely to set standards for electric vehicle (EV) batteries soon. The proper action from the Indian government may improve the EV situation in India.