Sodium Batteries for Electric Bikes - Prof. Amreesh Chandra

Battery Generation by Patrick Rosen and Lena Peters. Brought to you by Celeste. This podcast is brought to you by the Helmholtz Institute On and Celeste, the Center for Electrochemical Energy Storage, On and Casual Germany. Welcome back to Battery Generation, your podcast on electro-mobility and European battery research. So today we have a very special guest. It is Professor Amrish Chandra. Hello. Hello, Patrick. How are you? Good. Let me introduce you to our audience. You are a professor for physics at the Indian Institute of Technology in Karakpur, West Bengal. As a scientist, you are among the first developers of sodium ion batteries in and for India, which is really, really exciting. But that's not all. Very soon, you might become the first sodium ion battery producer. And for that reason, you want to equip electric bikes with sodium cells. So, Professor Chandra, what's the story behind all this? Thank you, Patrick and Lena, for inviting me for your podcast. The story is very simple. As we move towards the electric mobility, India wants to have batteries which can be made in India and can be used in India. Till few months back, we did not know that there were lithium reserves in India. But yes, sodium was always there. And sodium having a similar chemistry like lithium was always known to the community that it can be used for battery technologies. And that is why around seven years back, Indian government started specific calls for research in post lithium chemistries. And that is where we were funded by the Department of Science and Technology in India to develop sodium ion batteries. And our journey on sodium ion batteries started. And luckily, we have been quite successful in our journey. And very soon, you may see batteries developed by us in the Indian market and right from small scale usage to electric vehicles. That sounds very exciting. So, let me get this right. As a university professor, you are exploring battery materials. And as an entrepreneur, you are going to sell and possibly produce sodium ion batteries. Is that correct? That is very well said. We are a team of researchers who are working right from the fabrication of batteries using the materials which are synthesized by us. The IPR of those materials are owned by us. And also the design of the batteries are owned by us. So, we are not dependent on anybody to supply materials to us. And we are quite self-sufficient to take it forward without having the problems of fighting patents from other companies. In addition to that, we will be sending it to the market via an industry route. So, the industry will tie up with us mass-produced using those technologies where the name of my Institute, that is Indian Institute of Technology, Kharagpur, and the industry will be jointly promoted. We don't want to reveal too much. We'll talk about your sodium ion cells in a while, but very quickly. Why are you producing sodium ion batteries and why for electric bikes, especially? There are two aspects to this question. Why do we do it? Because lithium-based technologies are well-established, but we do not have lithium ore which is still being mined in India. So, for even the raw material, we are dependent on outside countries. And that obviously, as we want to become self-reliant on battery technologies, we would like to have the raw materials which are being produced by India itself. And second comes the question about e-cycles or e-bikes, which also have a pedal in it. That is where our first interest lies, because if you see every Indian household has a cycle. So, we would like to address the problem or access every Indian household, and that is a huge market. So, even if you say that there are 1.5, 4 billion people in the country, and if you count just half of it households or one-fourth the number, we are talking about a number which can be quite high, hundreds of thousands of cycles. And if we can make them electrically powered, it serves a lot of purpose, and it gives us a big market. E-bikes are also getting very popular here in Europe, in Germany. Many people are using them. I have mine in repair right now, but also use it to commute to work. When looking at India, where do you see the people who will use the bicycle? Do you see it more like in the private sector, like you mentioned right now? Or is it also something that will be very important in the business sector for transportation of food, or maybe even to cook tuk tuk with sorry mine batteries? So, as of now, we already have e-bikes in the market, and they are being used by people ranging from school going kids, like in my house, my son uses e-bike to go to school, and I also have e-bike in my own research team for students to move within the academic campus. And also we have e-bikes used by food delivery people at large, but in addition to that, the trend of going for a cycling tour for fitness is also growing in India, and especially after COVID when everybody is more focusing on fitness. So, people are going for long cycle tours, and that is where the advantages of e-bikes would come in, because you can drive, let's say 25 kilometers in one way, but on the way back, you would like to use a backup system, which brings you home on time without you getting tired. So, it is a range of application we are talking about. How is the transition towards electro-mobility going in India in general? Do you see many EVs on India's roads, for example, tuk tuk or even electric bikes already? Yes, at the tuk tuk level, most of the conventional tuk tuk which you see in Indian movies have been replaced. And what you see today are 75% tuk tuk which are on batteries, but these batteries necessarily may not be on lithium-ion cells, some of them are on lead acid, and some of them are on lithium-based systems. So, tuk tuk are nearly 80% tuk tuk has been replaced. Coming on the cycle side, the number is increasing on daily basis, and typically all the food deliveries, the Amazon's, the people who are having packages being delivered, they are using e-bikes. Coming to cars, the target is to have at least 40% to 50% of the cars to have e-support, not if not fully e-cars, but sub-hybrid kind of cars by the end of this decade, nearly 30% to 40% of the cars would end up being a hybrid type of car. So, it's a massive movement going across the country. So, speaking of bikes especially, how do I picture, how do Indians charge their electric bikes? We have heard of crazy swapping concepts that are already working quite nicely, that people just swap their batteries basically. That is something Europeans are not used to at all. Could you talk on that please? Yeah, the concept of swapping batteries is very much acceptable to us, because it gives us the time to charge the batteries while the vehicle is being used. So, rather than having a one battery pack, you will have two battery packs. And if one gets discharged, you just go to a station, put your battery back for charging while you take the second battery pack and install and start running it. So, this is a concept which is quite prominent and is being proposed by many companies, swapping of batteries. But as of today, you have charging stations being provided by most of the e-bike suppliers. So, you will have a charging station or a doctor's are being supplied to the customer along with the e-bike. And that doctor can be directly used through the socket of your household grid-based supply, and then you can charge the vehicle. So, both the concepts are working. It depends in which part of the country you are and where the infrastructure is being developed. So, if I imagine that is that like a renting system, so I rent the battery and I swap it, or do I buy a battery but then swap it for another one or like who owns the battery? So, the concept is like this that if you have the swapping concept, then basically you will be buying one battery. And then once it gets discharged, you will go and put it in a station exchange station and take the battery which is already charged, but with similar characteristic and put it in your bike and you move forward. But because both the batteries are looking similar, it doesn't matter whether you are using another battery. So, you are paying for one battery, but you can go on swapping as and when required. And so, when the battery dies, what happens then? Like batteries have a lifetime, right? Yes, use it a lot. What happens if my battery packs basically dead, but I put it in and I take another one who will replace them. Because of now, the car manufacturers are giving a warranty period of 8 years. So, if your battery pack dies in 8 years, they will replace the battery. So, that is similar kind of warranties are being given to the other users as well. So, it does not matter that if you are buying, you pay for one battery, but if that battery is dying, you already have the warranty for next 8 years and you will get a new one. So, that is covered in this swapping process. Awesome. I honestly admire the practicality of your approach there because I kind of doubt that it would fly in Germany because people would be like, but you didn't charge it right and my battery is still better. And now I have a battery that's not so good. I think there might be a lot of fuss happening. Let us, I will add to this point is that the charging is like a box station. So, what will happen that when I put a battery in, it is being charged by a standard of the company itself. So, I don't come into picture and then it is a standard which is to be followed. And so, whether you put a battery in or I put a battery in, the standard remains the same. So, the output remains the same. Then let's talk about your sodium ion battery cells that you will introduce to the market very soon from our previous podcasts. We have learned that there is a huge variety of electrode mixes that are possible within the sodium ion world. Which one did you choose for your intentions especially on cathode, on anode and electrolytes? Okay. So, the fun of working with sodium based systems is like this that you don't have any standard combination which is given. And with our experience, every material behaves independent to the other material. So, if I, for example, if I pick up an electrode material which we have been using, which is sodium ion phosphate, it works with a different electrolyte than the other material like sodium titanate which is also used in sodium ion batteries. So, for every combination you will have to standardize, optimize the anode, the cathode as well as the electrolyte. For example, for sodium ion phosphate, we have been using sodium ion phosphate as a cathode, sodium hydroxide as an electrolyte. But we have been using a standard sectorator which is available in the market. And on the anode side, we have been using hard carbons or carbon-coated molybdenum sulfides. So, they, these are the combinations which we have been trying. But if I go to another material, this combination doesn't work. So, every sodium based material needs to be optimized with another material. Okay, so sodium phosphate, sodium hydroxide and hard carbons made probably out of bio waste. These are all materials that are, I guess, abundant and available in India, right? The raw materials to make these materials are abundant. They are not naturally occurring. So, you have to synthesize these materials. So, the raw materials which we require be sodium nitrate or sodium metal or any other kind of stuff, that is abundant. And from there, we synthesize these materials using a large number of protocols. But again, we're talking that you avoid vanadium, you're avoiding copper, lithium, cobalt and even graphite, which is really great because then you're not dependent on China anymore, right? Yes, as of now, we are working on only those materials which are available in India. And that was the mandate given to us by the funding agencies. Use these stuff which you have in India and become self-reliant. And your first cells, how many what hours do they provide? So, we are starting from coin cell onwards. So, we are looking at around 235 to 250 milli ampere hours per gram. That's the kind of specific capacities we are looking at. And they are comparable to lithium-based coin cells which we already have in the market. Or to an extent they are better than many lithium-based coin cells which are marketed in the various companies. That is really exciting since that is something I wouldn't necessarily expect. In the previous podcast, we have heard that sodium ion batteries can really keep up with lithium ion batteries when it comes to gravimetric or volumetric energy densities. So, you're saying your cells, they provide the same energy density, then comparable lithium ion batteries. That is great. Yes, because if you do the theoretical calculation, then the theoretical energy density of sodium is comparable or slightly higher than lithium-based. So, theoretically we know that sodium-based technologies should give you that kind of specific capacities. It was only the limitation on the material side which was preventing us to go and achieve that target. But with the expertise and knowledge on materials, one can achieve those kind of numbers. It's very impressive. And now if I imagine the battery, you mentioned that for a Tuk-Tuk battery maybe it's an ADL lifespan that is guaranteed by the producer. How would you see the lifespan for your batteries? How long do you think they can work before they need recycling? So, Linda, if you see these batteries, the massive advantage with sodium comes in that you can take it to zero-volt and charge it again which is not true with lithium. So, if that concept is there and we are able to make large batteries with this advantage, then I believe that the life cycle would be similar or even higher because then I don't use the battery for three months. But then when I charge it, it regenerates. Whereas lithium if you don't charge it for three months, then it is dead. So, that is a big advantage with sodium. So, I believe that the life cycle of this would be quite high. I cannot comment the exact number because we have not reached the ADL period. So, let's not comment on a number which is still not achieved by us. That sounds nothing short of a game changer because I mean you have good performance levels, you have a good lifetime for the battery. And then also if we look at the environmental footprint, maybe you can elaborate a bit on that but sodium ion batteries, as we have learned so far, do have a much better environmental footprint than lithium batteries. I am very happy Leonard that you actually raised this question because many people working on this topic we tend to forget this. This kind of studies are done by the whole calculation which is called life cycle assessment studies, the LCS studies. And my group also has a division which focuses on LCS studies. So, in addition to just talking about sodium material, people sometimes talk about you have an X morphology of a particle which is best performing and should be used for batteries. It doesn't work like this because the best performing materials may also have a very high carbon footprint and they cannot be used in batteries and they will not be used in by the industries. So, for sodium based materials because our transportation cost comes down quite significant in India, the storage cost comes down quite significantly. For India, the carbon footprint which we have from sodium based materials is significantly lower than what we have from lithium and that gives us a pick advantage. Another advantage would be the costs themselves. Could you talk about your first cells in terms of price or is that hard to measure? No, it is not hard to measure but Patrick, if you see the way we have done it, it is like a lab level not done by the economics in the company. So, for us we have procured a lithium based cycle from the market and then we have our own E cycle which was running on sodium and based battery. So, then we did the LCA study, then we did the cost analysis and we have seen that sodium based batteries reduce the cost of the E cycle by 25% to 30%. That is great. I have even heard greater numbers but that has been a while, maybe five years ago, these measurements go up to even 40% reduction of costs. So, that sounds great anyways. How about safety of these sodium and battery cells? Have you been able to test them already? Yes, we have tested them in, there are three kind of tests which we have done. One is temperature because if you know in India, temperature variation can be significant. For example, winters can be zero degree temperature and in summers we can have temperature as high as 45 degrees and during operations that the cells can get heated and you can have temperatures of the cells going up to 70 degrees or so. So, we have tested our batteries in the range of 10 degrees to 65 degrees C and up to 70. So, we find that these batteries are quite stable, they do not degrade from 10 to 65 degrees and beyond that the performance do not change too much. So, we believe that their usage up to 65 degrees is quite useful. I am not quoting it below 10 degrees because these are equals based systems. So, if you go to a zero degree then the electrolyte starts to get frozen and the performance will go down and therefore I am not quoting zero degree. I am giving a reasonable number of 10 to 60 degrees or 65 degrees. Professor Shandra, this is too good to be true, this sounds really outstanding. Is there any downside, any challenge you see when now producing sodium ion batteries? Now you have listed all the advantages, is there any disadvantage? Yes, there are disadvantages as of now we need large scale production of sodium based electrode materials. That is a different area altogether because most of the companies, most of the manufacturers have moved on towards lithium based technologies. So, you will have to develop synthesis protocols, standardize them and then convince the manufacturers of these electrode materials to produce them in bulk so that the batteries can be produced in bulk. That is one of the aspects. In addition, as these cycles or these batteries run for a couple of years then we will have to find out what is the protocol of discarding these materials as they undergo some phase transfer measures. And that is an ongoing study and hopefully in couple of years time we will know what are the byproducts which become available as they are running as a function of time, as a function of temperature and then how do we address those problems. So, there are massive issues which need to be addressed. Can you tell us a bit more about the plans on recycling, how recyclable is that battery you're planning to produce? What materials can you recover and what are maybe not even worth recovering because they are so cheap and maybe renewable anyway. So, for the present site batteries which we are using for stationary applications or small scale applications like toys, the remote controls, the calculators, the watches. We are expecting to recover iron or some extent of sodium from it but other than that we don't want to recover anything else because they are not worth it. So, we don't have to recover very high expensive components like nickel or cobalt which is there in the lithium based system. So, these are not there. So, on the second aspect of your question which was regarding the cycling effect, a typical coin cell is expected to run for a thousand cycle. And the advantage which we are having is we already have them tested that you run it for six months or a thousand cycles. And once they stop working you put a small charger again and then it is alive again and then again you can run it for six months. So, we are having coin cells which are running for a couple of years or at least a year or so and they discharge and you can charge it again and take it forward. I believe similar things would happen as we go to larger size form factors and then they would be having a cycle life of a thousand times or more. Well then let's talk about the production of your sodium ion batteries. How do I picture a done and industrial pack? You have up until now produced lap cells. That's a huge step towards huge companies building batteries. How do I picture these packs? The way forward which we have we have a non-disclosure agreements with three major companies in India and as we go along they are already investing in setting up the fabrication unit for these batteries. So, first we would like to start with coin cell then we would either go to the cylindrical cells and the pouch cells. For e-bikes or e-bikes without pedals we are focusing on the pouch cells but for small scale applications or toys level applications. We are talking about coin cell fabrication which is a standard process and both of them do not require any new knowledge because that is available from the lithium based fabrication unit. So, it is only the change in the material but the know house are already available. You don't need to invest in some new equipments. And what form factor would you use for the bicycles that we talked earlier? We would be talking about 18650 cells. This is what is being used and those are the cells which are actually using German e-cycles. I saw many of them and they are using the 18650 cells and the requirement sent to us by the e-bike manufacturers are also in 18650 cells for the e-bikes with pedals. Now India is quite a huge country and surprisingly there is currently just a handful companies claiming that they will soon build up lithium ion battery production plans. I thought Indian producers would be probably a little faster than Europeans are so does India still purchase most of these cells from China right? There are manufacturers buying lithium batteries from various parts of the world. I cannot pinpoint from which country because that is for the company people to answer. Coming in why India did not have its manufacturing unit? You don't want to manufacture something for which you are dependent on the very raw material. For example lithium if you don't have lithium if you are dependent on a country to get lithium from somewhere else and then start manufacturing then it is not a sustainable process. In last 4-6 months we have found out that India also has significant reserves for lithium and that is where the interests have come in and immediately our industry people have come forward and said now we have the resource we will make our own lithium. With the work which is being done by me and along with me by many other colleagues in different suits who are working. People have also got interested in sodium based energy storage technologies and the reason is that we have the raw materials for the sodium based energy storage technologies. And it is much better for the environment if you can actually replace lithium with your sodium technology that would be nothing short of a game changer I think in the transition to an electric world. In addition to that this would standardize the uses of electric vehicles because you can have every country making its own battery because sodium reserves are there. The most common is your sea water you can extract from sodium from there in a sea and then you extract and somehow use it as a starting from material. So then if you can make the batteries in every country first of all you increase the job market is enormous. You introduce sustainability it will be available for us and our future generation and you also ensure security of supply and that defines energy storage or generation technology and that is what we are working at if a technology can take care of these three terms what else do we want in our research. Thank you very much for your expertise we're wishing you good luck with your mission that was professor Shandra from the Indian Institute of Technology dear listeners now it's your time if you got any questions comment below send us an email towards hello at battery generation dot com with the battery topic of your choice and again follow us and Spotify and Apple Google or YouTube thank you very much for listening see you soon bye bye. This podcast is also supported by the Cots who Institute of Technology will university the German aerospace center and the center for solar energy and hydrogen research bottom wooden back.