The transition from Lead Acid battery to Lithium Ion battery: Why is the shift necessary? – Part 2
The first part of the article "The transition from Lead Acid battery to Lithium Ion battery: Why is the shift necessary?" introduced the need of storage and further detailed about the lead acid battery. It also discussed major disadvantages which were associated with the lead acid battery. This part of the article shall educate its readers about Lithium Ion battery, its working and its advantages over lead acid battery. Further it shall also detail the market dynamics of Lithium ion battery and its applicability in the Indian sub-continent.
While considered to be one of the most emerging technologies in the storage industry, lithium ion isjust 50 years old. Similar to most of the battery technologies, the lithium ion battery has cathode, anode, electrolyte and a separator. The cathode of the battery is usually made up of combination of lithium & oxygen (known as the "active material"), a conductive additive and a binder. The anode of the battery is usually made up of graphite which is known for good structural stability, low electrochemical reactivity, better affinity to lithium ions and lower price. The most common electrolyte used in the battery is a lithium salt, such as LiPF6 in an organic solution. The separator in the battery is usually made up of polyolefin as it has excellent mechanical properties, good chemical stability and lower costs.
Figure 1: A typical Lithium Ion battery (Source: Samsung SDI)
The Li-ion battery works on the principle of electron-ion exchange, similar to most of the batteries. During discharging, the electrode with the high electron affinity will release electron (which is known as anode) and the electrode with the low electron affinity will gain electron (which is known as cathode). This electron would travel through the load and thus allowing the battery to supply energy. Each component however has a specific function to perform. Cathode primarily determines the battery capacity i.e. higher the amount of lithium at cathode, the higher is the battery's capacity.
The anode enables exchange of lithium ion from/to cathode while charging/discharging. The electrolyte is one of the most important components of the battery. The salt present in the electrolyte allow only the passage of lithium ions and thus forcing the electron to be move via the external circuitry only thereby supplying the required energy to external load. The separator further facilitates such movement of lithium ion through its internal microscopic hole while also forming a physical barrier between the electrodes.
Let us now understand the (few important) existing battery technologies of lithium ion:
- Lithium-Cobalt-Oxide (LCO): One of the earliest commercialized chemistry (in 1985) for Lithium ion batteries were the LCO batteries. These batteries had high stable energy capacities which allowed them to be utilized in applications in laptop, mobile phones, etc. However these batteries had higher thermal runaway, meaning that there was a fair chance that the battery possessed risk of exploding if it were damaged or overcharged. This directly led to compromised safety and life span of the battery.
- Lithium Iron Phosphate (LFP): Discovered in 1996, LFP batteries offered good electrochemical performance with reduced resistance, excellent safety and long life span but moderate specific energy and a lower voltage than other lithium-based batteries. Its excellent thermal stability and enhanced safety enabled it to be utilized in applications which needed higher load currents and endurance, for ex: EVs, solar PV plants, UPS.
- Lithium Nickel Manganese Cobalt Oxide (NMC): One of the most balanced performing lithium ion batteries is NMC. The cathode combination ratio which is usually one-third nickel, one-third manganese and one-third cobalt means that the raw material cost is lower than other types of batteries. Such combination further also allows NMC battery to be either utilized as a high energy battery or a high power battery. The battery found its application in EVs, medical devices, industrial applications, etc.
Figure 2: Comparison of various lithium battery technologies (Source: Battery University)
Let us now understand the advantages of Lithium ion battery over lead acid battery:
- Light weight and easily portable: The lower weight of the lithium ion battery (compared to other commercial battery technologies) is probably one of its primary advantages. This is primarily because the battery utilizes lithium as its main components, which has both lower density and highest electrochemical potential. This further means that the battery has both higher energy density (3~4 times higher) and power density (3~6 times higher) which makes the battery even lighter when compared to lead acid battery. Additionally with the lithium battery utilizing dry electrolyte & electrodes, its installation and transportation becomes stress-free.
- Shorter charging times and high energy delivery rates: With the application of storage now diversifying to in EVs, power plants, micro grids, etc. where the end application calls for the devices to be charged quickly and deliver high energy in a short span of time, lithium ion seems to be the perfect match. Compared to lead acid battery, the charging time of lithium ion battery could be reduced by 60% which makes it suitable for such applications.
- Higher cycle life: One of the major concerns for storage is the duration up-till when it could be used. A battery is known to be rendered useless if its capacity reaches to 80% of its rated capacity. A typical lead acid battery runs for 300~500 cycles which means that it need to be replaced between every 1~2 years. A lithium ion battery on the other hand runs between 1,500 to 2,500 cycles which is almost 5 times more than the lead acid battery.
- Better performance in extreme climates: Considering a case of India where extreme ambient temperatures are normal, a battery is required to be operational in all such conditions. Comparing both the battery types, the available capacity of lithium ion battery is better compared to lead acid battery (refer Figure 4) at both the extreme temperatures. This directly points out that lithium ion battery could be utilized at much better levels at all the temperature ranges.
Figure 3: Capacity Available versus Temperature (Source: ALL CELL)
The above factors make it clear that the Lithium Ion battery (and its variants) have a clear potential of covering almost all the applications which utilizes lead acid battery. The battery technology which has started seeing the light of the day is expected to have an exponential uptake, thanks to few specific applications like EVs, energy storage, consumer electronics, E bikes, etc. EVs are already creating a buzz in the automobile sector primarily due to the ill effects of traditional fossil based vehicle. The lithium-ion battery demand for EVs is known to grow from around 200 GWh in 2020 to 1,748 GWh annually by 2030, showing a rise of 900%. Such rise is primarily known to fuel the growth of the battery technology is the next decade. Further with the increased electrification around the world, the need for 24x7 reliable supply of electricity is increasing. With the lifetime limitations of lead acid battery, it is much expected that the grid managers and the generators shift towards lithium battery. It is almost known that no technical breakthrough can make it to the market if it is not cost effective and the same is true for lithium ion as well. The costs of the battery in 2019 have reduced drastically to around 83% when compared to thatin 2010. This cost is further expected to reduce by 65% and stay at around 60 $/kWh by 2030. Such price drop would further fuel the growth and adoption of lithium ion battery.
Talking about the Indian scenario, the country has announced bold plans to adopt and integrate (directly and/or indirectly) storage or more appropriately lithium ion batteries in its energy mix. The National Electric Mobility Mission Plan (NEMMP) aims that the country starts manufacturing, adopting and utilizing electric vehicles. It is further also believed that all the vehicles sold after 2030 shall be electric in nature. The National Energy Storage Mission (NESM) adds on and supports the NEMMP in the country. It aims that to set up the entire supply chain for lithium ion battery thereby capturing the market opportunity between INR 2,000 to 3,000 billion. While the above two plans are still on papers, the scheduling and forecasting regulation (already passed in various states) for solar PV plants directs them to provide a forecast of their generation. A regulation like such demands the power plants to be equipped with adequate storage to ensure that they maintain steady and declared energy output.
Figure 4: Annual Lithium Ion battery demand (Source: Bloomberg NEF, Avicenne)
We at Waaree Energies keep close look at the market trends and in order to facilitate the shift which Indian storage market is undergoing, we have started a new lithium ion battery manufacturing plant. Capable of producing battery packs of both NMC & LFP technology, our batteries could be used specifically for EVs, power backup at grid level/power plant level, solar street lights, etc. These batteries are tested in accordance with all the national and international standards ensuring that the end customers get more than desired returns on their projects.
Figure 5: Typical batteries offerings by Waaree energies
Let us all pledge to make solar energy the primary source of energy in the near future.
RAHE ROSHAN HAMARA NATION