CK2018: Battery technology
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The document discusses battery technology for electric vehicles. It notes there are uncertainties around evolving battery chemistries, material availability, policy changes, and demand. Original equipment manufacturers have limited research and development capacity for batteries, and connections between research institutions and the auto industry are weak. The document outlines challenges for automakers around battery life, safety, performance, cost, resources, and disposal. It then discusses ongoing innovations in lithium-ion and new battery technologies like solid-state, graphene supercapacitors, sodium-ion, magnesium-ion, and flow batteries. Charts show declining battery costs and increasing energy density, with costs expected to further decrease through production growth and technology advances.
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CK2018: Battery technology
- 2. EV components Batteries BMS Electric motors Power Electronics
- 3. • Four primary levers of uncertainty: Evolving technology/cell chemistry, material availability, policy direction, scale of demand • Limited R&D capacity within OEMs – unclear focus • Connection between R&D institutions and the industry is weak Challenges from the OEM perspective
- 4. Battery characteristics Life span Safety Performance Energy density Power density C-rate capability Cost Resource constraints Disposal risks Recyclability
- 5. Li Ion battery technologies Source:BCG research
- 6. • Innovation in the Li-ion battery space continues on many fronts, including new cathode and anode materials, membranes, electrolytes, electrode processing and battery assembly • New solid and liquid electrolytes • Several automakers are working on their version of all-solid-state batteries • Graphene supercapacitor technology • Sodium-ion, magnesium-ion and other metal anodes, and sulfur and air/oxygen cathodes, as well as high energy density flow batteries Innovations in battery technology
- 7. Encouraging trends overall 0 200 400 600 800 1000 2009 2010 2011 2012 2013 2014 2015 2016 BatteryCostUS$/KWh) 0 50 100 150 200 250 300 350 400 200920102011201220132014201520162017 BatteryEnergyDensity(WH/L) Battery costs are set to fall further with Increasing production, technological advances and Indigenization Expected to reach about 410 Wh/L by 2022
Editor's Notes
- Thanks everyone for joining us today for this session. Although the session name says battery technology, In this session we are also going to focus on technology more broadly as well given the larger theme of bus karo. We have a mix of experts with us today, including those with experience in manufacturing, R&D, city level applications and logistics applications of EVs. So this should be a very interesting discussion bringing many different experiences and applications of EVs into this conversation. With this presentation we just wanted to set the context, and provide a quick background on how technology is evolving that would be relevant to all the conversations to follow.
- To start off, like I said, While in this session, we will focus more on battery technologies. It is important to mention that all of these components that constitute an EV are undergoing technological improvements that are crucial as well. And the other speakers may touch upon some of these areas in their relevant conversations. I just quickly wanted to run through some of these developments as well before we dig deeper into battery technologies. Battery management systems (BMS) as most of us know has two main roles: the first one is to monitor the battery to determine information such as its State of Charge, State of Health and Remaining Useful Life. The second role is to operate the battery itself in a safe, efficient and nondamaging way. Passive balancing methods have been used in the past, but it is not an efficient solution. Second generation batteries will probably rely on active cell balancing, the benefits of which longer life, increased safety and a higher power capability, and that’s beneficial specially because it comes at an incremental cost. The reason that BMS is just as important as batteries is because it can significantly improve the efficiency of EVs and extend the life of batteries. As these two parameters are crucial for optimizing both range and life cycle cost, so improvements in this technology could enhance greater adoption These are important for Lithium-ion technologies since they are more prone to damage and present a risk of fire or explosion. Plus, they are expensive so you would want to extend their life as much as possible. So what I wanted to say is that BMS are quite important even if we are not focusing on them in this particular session. The next is Electric motor. We know that electric motors have many advantages over internal combustion Engines. For one, the efficiency of the conversion from electrical to mechanical energy is high at between 70% and 95%. They have high torque and power density and better torque characteristics at low speed. It is also possible to use electric motors as generators during braking to recover energy. At one point, DC motors used to be considered as the most suitable technology for EVs. They are not so complicated and not so expensive, but they are more prone to wear and tear. AC motors are less expensive, however they require complicated and costly power electronics, which increases its overall cost. But, their big advantages is higher power density, which allows u to make them smaller and lighter motors, which maximizes the range for a given battery capacity. And again, there are different type of AC and DC motors, but we wont get into that here. But Future possible improvements of current electric motors are aimed at reduction in the cost of the high temperature permanent magnets, the development of controllers for safer operation, and a decrease in the number of sensors in the motor. The next is Power electronics which is essentially the intermediate between the battery, a DC current source, and the AC motor. It is composed of an inverter. The efficiency of power electronics is typically between 95% and 98% [29]. In the past decade, several technological impovements have been made but but there are challenges and many improvements still need to be made to make it truly efficient. But overall, there certainly are developments in each of these areas that are driving EVs to greater efficency.
- Before we get into battery chemistries, I’d like to take some time to reflect on some of the major challenges that were highlighted by auto manufactures and OEMs in the workshop we had held with Niti Aayog earlier this year. Some of these conversations spurred us to look at battery technologies more deeply. There are four primary levers of uncertainty that were identified by the OEMS i.e. Technology/cell chemistry, uncertainty around material availability, unclear policy direction, unclear scale of demand of specific technologies. Taking the case for Li Ion, it was discussed that even a small chemistry variation takes a few years to get to the manufacturing stage, so that’s a significant challenge. R&D staff in every organisation is limited, so this is a clear challenge and It is unclear today where companies should focus, whether on R&D or on manufacturing with established chemistries. It is unclear what the raw material availability is in India today. We heard from PSUs that Lithium is available in India, but classified as an atomic mineral, hence it’s real availability as a resource within the country is not clear to the private sector. Lithium is available in many other countries however, and Afganistan has the largest established reserves so far. The resources are concentrated in a handful of countries (only nine countries and 95% of global lithium production comes from Argentina, Australia, Chile and China). But it is a clear challenge in terms of resource security, and whether we would want as a country to depend as much on other countries is a question we have to ask ourselves. Especially with countries like China and US, which are actively seeking control of lithium mining assets in other countries. Then there are other minerals like Cobalt which another critical component of current battery chemistries, 50% of which comes from Congo, and the price is very volatile. There may be other limiting raw materials used for processing such as Copper coils, which one tends to sideline but is also a clear challenge. To be abe to handle these challenges, the feedback mechanism between R&D and industry is currently weak and needs to be strenghtened with parternships and coalitions. Research results are not disseminated widely enough which was identified as another big issue. Which led us to this partnership with IESA to understand how some of these challenges could be overcome.
- So there are essentially a number of characteristics that define batteries, and different cell chemistries that impact different characteristics to a battery. Safety (such as fire risk) Life span (number or charge and discharge cycles and overall battery age) Performance (peak power at low temperatures, state of charge, and thermal management) Energy efficiency (%) Energy density (energy per kilogram of weight or per Litre of volume, Wh/kg, Wh/L) Power density (power per kilogram of mass or per Litre of volume, W/kg, W/L) C-rate capability Cost Environmental/disposal risks/Toxicity Resource constraints (materials requirements)/ security Recyclability Others These are all important characteristics when it comes to defining a battery and its suitability. Technological advancements are essentially focused on improving these characteristics of batteries.
- If we talk about established chemistries, Li-ion batteries are the current enabling technology and are the fastest growing segment. They have advantage of high energy density, relatively light weight and the ability to retain capacity after hundreds of recharging cycles. Current commercial batteries use liquid electrolytes and predominantly graphite (G) or lithium titanium oxide (LTO) anodes in combination with different cathodes Even within these established chemistries, there are trade-offs between the primary Li Ion technologies as well, with different compositions faring differently on different characteristics On the price side however, prices for Li-ion cells have been decreasing at an average rate of 6-8%/year from over $1000/kWh in 2010, so that’s a very good trend. We do see spikes based on increased demand, but overall it’s quite a stable trend.
- Innovation in the Li-ion batteries is happening on many fronts, including new cathode and anode materials, membranes, electrolytes, electrode processing and battery assembly Li-ion batteries they still have an inherent ability to overheat and catch fire These issues have spurred other improvements in Li-ion technology which include new solid and liquid electrolytes, eliminating or replacing the polyethylene separator with less flammable options such as ceramic-coated or Kevlar membranes. It is projected that swapping liquid electrolytes for solid ones could provide a 15-20% increase in energy storage capacity But the most anticipated competitor to Li-ion technology is an all-solid-state battery andhere are many manufacturers working in with Solid state in terms of R&D all over the world. Many other battery technologies are currently in development (sodium-ion, magnesium-ion and other metal anodes, and sulfur and air/oxygen cathodes, as well as high energy density flow batteries), and may have significant advantages over the most anticipated technologies, but have not made it to the productive end of the “Hype Cycle” yet. Innovative concept that a Professor in the Department of Mechanical Engineering at Carnegie Mellon University has developed that quantifies a battery chemistries position with respect to others. And of course, this is by no means exhaustive. It is such a rapidly growing sector that the canvas is huge. There are several innovations that I haven’t been able to cover given the paucity of time such as supercapacitors. But hopefully some of these will come up in our conversations today, and hopefully we can talk about some of the innovative applications of existing technologies as well.
- There are encouraging trends we have been witnessing over the past decade, with battery costs falling and energy densities increasing. However, specifically for India, there are significant challenges around increasing manufacturing base. RMI suggests that India will require at least 800 GWh of batteries per year in order to meet the demands of a 100% EV mark. That may not be the target for now anymore, but may be a target for the future. Even a fraction of this is quite significant, so there is enough demand to drive up domestic manufacturing , but there are challenges around limited or unknown reserves, lack of a base- very nascent battery industry, and a high perceived risk due to the factors I mentioned in terms of uncertainties earlier in the presentation. On that note, I’m going to hand over the mike to Dr. Walawalkar who is going to take you through, in further details, some of the broad technology trends and important factos that determine technology selection.