Greendzine claims their vehicle chargers are half the size. Plus, they have a LEGO-like modular system. One unit can power an e-bicycle. Two can power a 2-wheeler. Three can power a car. What tech has enabled these innovations? Co-founder Karthikeyan Sundaram explained the technology to Yashasvini Razdan from Electronics For You and gave a few
additional insights as well.
You Claim that your Chargers are like LEGO Modules. What’s your Unique Recipe?
We have 30+ intellectual properties in design but this is The One. The innovation that we have got here is in power electronics. You cannot connect two power-generating converters in a series, because you would get into load-balancing issues. We also faced that problem but we were able to solve it through multiple iterations, and we used a special switching mechanism called GaN FET. We were able to switch GaN FET switches at a frequency of 1MHz, increasing the power density of the charger, which is a great achievement in power electronics systems. With this switching frequency, as well as the hardware we developed, plus the homework we did, we were able to connect the modules in series and parallel to enhance both current and voltage.
Why do you use GaN FET? What’s special about it?
We are using GaN FET because we wanted to make sure that we are switching at a frequency of 1MHz or more. If you use MOSFETs and other FETs available in the market, you can’t switch at that frequency. If you try to do that, it starts burning. Secondly, when we switch at a higher frequency, the overall size of the power electronics grid will come down. So, we wanted to make a compact and highly efficient power electronics converter and that’s why we used GaN FETs.
Was this Innovation Intentional or Accidental?
The initial idea wasn’t to use GaN FETs, but the idea came from a need as we had to connect our modules in series and parallel. We were making multiple electric vehicles and designing different battery packs. We realized that we had to buy different chargers for different sets of batteries. So, we decided to go for one charger for all the batteries, but that type of configuration was not available in the market. We decided to solve this problem ourselves.
We brainstormed and arrived at the concept of connecting small modules into series and parallel to arrive at a higher configuration or removing them to achieve a lower configuration. We call this concept an Infinity Charger; there is no limit for voltage and current in this configuration.
What’s the Secret behind Chargers that are half in size?
It is the technology called Immersive Cooling. This tech enables you to immerse a power-electronics board in a water-like liquid and thereby develop a more compact module. Our charger is half the size of the ones available in the market but can deliver the same capacity of power.
Any safety or structural challenges associated with having power electronics immersed in a liquid? Any risk of short circuits, etc, especially under extreme conditions like an earthquake?
There is no chance of a short circuit because this is a deionized liquid. It is not an electrically conductive liquid. It is only thermally conductive. It is safe. It helps to protect the battery from thermal runaway. Thermal runaway happens when the battery reaches a particular temperature and catches fire.
Using this immersive cooling technology, we don’t allow the battery to reach that temperature. The liquid effectively transfers the heat from the switch to the surface. The immersion liquid will get heated up and cool the switch instead. The surface will then get cooled by the surrounding liquid.
Did You Face any other Challenges in Manufacturing such Equipment?
Prototyping in India is a bit challenging, of course. Procurement of components is a challenging task. While researching what components to use, we had to try out different types of components available in the market that worked the best for our technology. The other challenge came up during design. When faced with a problem, we have to go through multiple iterations before we finalize a particular design, and most people don’t know when to stop these iterations. They continue to do it because they either want a perfect solution or they think that there is something better. So, the challenge is knowing when to stop and finalize a particular design.
How many members were involved in the development and prototyping of this unique technology?
We had a research team of five members initially who worked for 18 months to come up with this solution. The team has people who have expertise in power electronics and mechanical engineering.
Any mistakes made and/or lessons learned in the process of developing this tech, which you’d like to share with peer innovators?
Managing the aspirations of the innovators was a challenging task. Research work requires a patient mindset. When research scholars get upset over small failures, it becomes a challenge. That’s where the management team comes into the picture to encourage them to shed their fear of failure. We also faced certain challenges concerning resources. To motivate our team, we made them aware of the impact of their work. When they were clear about the purpose, things fell into place.
With the current condition of Indian roads and shortage of power, or rather inadequate distribution of power in India, what’re the opportunities that stand out?
We have excess power in India which is not distributed properly. Power generated in the grid needs to be stored somewhere, otherwise, it would go to waste. Batteries are the only way to store that energy. If you can generate clean energy through solar and store it in a place where you can replace traditional vehicles, that’s a great thing. India is not short on power. It has to be distributed properly and saved properly.
Many EV sellers are targeting end-mile delivery companies. Why is that so?
End-mile delivery is a very attractive market because the operational cost is less than that of traditional IC engine vehicles. A delivery worker may be covering 80 kilometers, on average, every day, and the fuel charges for the same could be anywhere between ₹250 and ₹400. But in electric vehicles, you may spend only ₹10 to ₹20 for two units of power. This is the math that helps companies adopt electric vehicles faster. It is not the electric vehicle companies trying to sell EVs but the last-mile delivery companies who find EVs useful in their operations, because of the low operational cost. That is why there is increasing adoption of EVs by end-mile delivery companies.
What are the future trends and technologies that you see in this space, especially when it comes to battery charging and chargers?
The time taken to charge would reduce drastically in the future. Presently, it takes an average of four hours. A few companies claim that it can be done in one or two hours but that requires a special charger as well as a special cooling mechanism, which will come in the future. Secondly, you will have a common pool of batteries where you can just go to the charging station, take the charged battery, and give back the discharged battery. This is especially beneficial for last-mile delivery. For personal mobility, people usually charge their vehicles at home. Charging stations for the last mile delivery will become very prominent.
Can you tell us about the challenges you faced ever since you entered this business?
I would like to highlight two things. One is the availability of talent. When I did my master’s degree in power electronics, I realized that very few people remain in this field. So, there is a lack of experienced people who are passionate about building something in power electronics. The second challenge that we faced was with respect to marketing. We assumed that since our engineering design and product are good, we could relax on the marketing front, but that was not correct. We learned marketing and sales. It was the biggest learning struggle we had to go through for a long time. If I had to establish a startup again, I would focus more on marketing, sales, branding, as well as engineering, and not the other way around. If a startup wants to be recognized, that is the way forward. Building a brand has been the toughest thing.
You can also check the Greendzine Official Website.