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Gigafactories and Energy Density

The High-Tech Future of Automobile Manufacturing

Metal.Digital: 09/04/2021

A huge number of electric vehicles are required to cut greenhouse gases from internal combustion engine-powered vehicles, necessitating massive scale ‘gigafactories’.  Lithium-ion batteries are today’s preferred high energy density store, with research into advanced and alternative technologies rapidly progressing.  Massive increases in demand for battery raw material inputs and the associated pollution implications makes efficient recycling essential.

Gigafactories Matter

The term ‘gigafactory’ was coined by Elon Musk, drawing on the Greek word for giant to illustrate the scale of required electric vehicle (EV) manufacturing facilities; Musk was also playing on the electrical term gigawatt expressing a huge amount of energy transfer.

Wood MacKenzie estimate if emissions from road transport are to be cut in half by 2040, some 900 million new EVs are needed to replace internal combustion engine-powered automobiles.  In 2019, the world’s EVs totalled just 10 million, requiring around 70 million new vehicles to be built every year.  Illustrating the extent of this challenge, today’s 100-year-old auto industry produces between 90 and 100 million conventional automobiles per annum, while Europe alone has almost 300 production and assembly plants.  Battery facilities would also be challenged by the need to grow battery output 10-fold to 3,000 GWh per annum by 2030; existing and planned battery manufacturing only represents 1,800 GWh.1 

In 2020, across the globe there were 119 facilities either producing batteries, under construction or planned, of which 109 were located in China, representing 70% of global production.2 

Market-leading Asian manufacturers such as CATL, LG Chem, BYD and SK Innovation control the bulk of production capacity.  These firms are now expanding into Europe with CATL building a plant in Erfurt, in Germany’s Thuringia region; LG Chem’s plant in Wroclaw, Poland; and Samsung SDI’s Goed plant, outside Budapest in Hungary. 

By 2030 it is expected there will be at least 16 battery plants operating in Europe, representing around 450 GWh of capacity, making the region the second largest after China. This is largely as a result of local manufacturers such as Northvolt, Daimler and Automotive Cells Company (ACC), the joint venture between France’s PSA and Total groups, ramping up production.3  Northvolt is one of Europe’s front runners, benefitting from strategic support from both the EU’s Battery Alliance and financing from the European Investment Bank (EIB).  Northvolt’s Skelleftea gigafactory is planned to have an output of 40 GWh on completion in 2021, while another factory planned in Salzgitter in Germany in partnership with Volkswagen is due for completion in 2024.4

Tesla’s operational gigafactories in the US are located in Fremont, California, producing around 500,000 vehicles per annum; and Reno, Nevada which on completion is expected to be the largest building in the world.  Outside the US, Tesla is producing Model 3s at its Shanghai gigafactory, with a capacity of 250,000 vehicles per annum, where Model Y production is also commencing.  A factory in Berlin is due to start production mid-2021, producing both the Model 3 and Model Y, with reports of further planned factories in the UK and another Asian plant in either Japan or South Korea.

Energy Density – The Holy Grail

Energy density is the measure of how much energy a battery can deliver in proportion to its weight, typically measured in watt hours per kilo (Wh/kg). Energy density is a critical attribute for portable batteries used within personal electronic devices and EVs, as these are applications under constant pressure to reduce weight and cost while increasing battery life.

The term should not be confused with power density, which is a measure of how quickly energy can be delivered.  An example of a unit with high power density is a battery powering a camera flash, which discharges energy in a short burst then rapidly recharges.

The energy density of lead acid batteries used within internal combustion engine vehicles is between 30-50 Wh/kg, while lithium-ion (Li-ion) batteries range from 50 to 260 Wh/kg; nickel manganese cobalt oxide (NMC) technology provides a range of 150-220 Wh/kg, while lithium iron phosphate (LFP) is 90-160 Wh/kg.5    

As discussed in NTree Technical Paper #10, Electric Vehicles Go Mainstream, historically a high cobalt content was used to achieve higher energy density however with increasing cobalt prices and concerns about the cobalt mining practices new technology has increasingly focused on the potential of nickel which is now recognised as the key component.6  In early technology such as NMC 111 the cathode contains equal quantities of each mineral, nickel use increased in the NMC 532 and 622, while the most recent high performance NMC 811 uses eight parts nickel for each of the other elements.

Li-ion Batteries Evolve

The first EVs, such as the Nissan Leaf, were powered by lithium manganese oxide (LMO) batteries, which were relatively low-cost but proved to have low durability.  Lithium iron phosphate (LPF) is currently commonly used in EVs manufactured in China such as by BYD, the world’s largest battery producer, where it’s valued for medium cost and energy density attributes.  MNC and NCA, two high nickel low cobalt technologies which provide high energy density at greater cost, are widely used in performance orientated western markets by manufacturers such as Tesla, Renault and VW, where longer driving ranges are essential to make EVs attractive to consumers.  By 2030 its estimated high nickel content technology will be in use in almost all EVs in western countries and around 50% of those in China.7

Next Generation Solutions

Pressure to lower costs, decrease charging times, increase operating ranges and reduce greenhouse gas emissions is fuelling extensive research manipulating the workings of Li-ion batteries by substituting materials and using alternative structures. 

There is a whole range of developments looking to improve the efficiency of the individual battery components – cathode, anode, separator and electrolyte – which cumulatively will provide significant enhancements in the Li-ion battery technology over the next 5-10 years. 

In one such development, Volkswagen has partnered with QuantumScape, a US battery specialist developing solid state batteries that promise greater energy density than existing Li-ion electrolytes.  Solid electrolytes replace liquid electrolytes through which lithium ions travel between cathode and anode, using a highly conductive ceramic material.  Solid electrolytes have the advantage of being chemically stable, allowing materials with higher voltage capacity to be used to produce lighter and denser batteries with higher energy-to-weight ratios.8

US based Evonix has designed a silicon-based anode to replace graphite within Li-ion battery anodes promising a 30% increase in energy capacity.9  Advances to cathode technology include research by the energy company Total into developing a lithium sulphur (Li-S) cathode technology that exploits the chemical characteristics of sulphur. As sulphur converts into different chemical compounds during ion transfer, providing up to four times the energy density of Li-ion, this is an innovation initially suited to the aviation and aerospace industries.10

Large Scale Storage Now Viable

Large scale battery-based electric storage that also applies Li-ion technology is expected to rapidly grow from 1.2 gigawatts in 2020 to 7.5 gigawatts in 2030.  The largest facility at Moss Landing has doubled California’s energy storage capacity, while New York’s Ravenswood 316-megawatt project is large enough to replace two gas fired power stations, capable of powering 250,000 homes for 8 hours.  In Florida, the 409-megawatt Manatee project will store solar energy capable of providing 900 megawatt hours of low carbon electricity capable of powering Disney World for 7 hours.11 

Alternatives to Li-ion technology that mitigate its high component costs and safety risks are being developed.  Technologies such as Redox Flow Batteries, using electrolyte material selected for their abundance (for example salt, iron and water), are being found to provide advantages of low cost, non-corrosive and non-toxic materials along with attributes of long life and high rechargeability.12

Recycling – Tricky but Necessary

If the International Energy Agency’s estimate of a global fleet of 125 million EVs by 2030 is accurate, demand for nickel and manganese could grow by 800% and cobalt by 150%.13  Such increases are expected to lead to consistently higher demand than planned mined supply; significant increases in mining supply are challenging as nickel mines require large-scale capital investment and take almost a decade to go from discovery to full production. 

Consistent excess demand is likely to bring about increases in mineral prices, enhancing the commercial case for battery recycling.  While the environmental implications of large-scale recycling are not presently well understood, its known that mining and refining activities account for 30% of greenhouse gasses associated with battery manufacture.  Europe’s leading battery manufacturer Northvolt is targeting 50% recycled raw material inputs by 2030 illustrating the importance the EU have regarding sustainability and considerations such as security of supply; sizeable EU funding alongside extensive battery regulations are expected to contribute to commercially viable recycling.14

As batteries aren’t designed for easy recycling or constructed to a common design, recycling is a complex business.  The initial recycling process, involving manual disassembly, is time consuming and dangerous as chemical instability creates a risk of fire and explosion.  The most common recycling method requires smelting to remove all organic and plastic materials, a simple process that is polluting and inefficient as much of the aluminium and lithium is lost.  The alternative hydrometallurgical process is increasing in use; batteries are first crushed, with materials separated by sieving and magnets used to produce a ‘black mass’ which is immersed in an acid bath to extract the nickel, manganese, cobalt, lithium hydroxide and graphite for reuse.15

Planned EU battery regulation is the most comprehensive of all countries, aimed to achieve greenhouse gas and sustainable targets while also establishing a globally competitive industry.  These complex and wide-ranging regulations include requirements for all EVs to have a carbon footprint declaration by 2024, disclose the amount of cobalt, lead, lithium and nickel used by 2027, in 2030 minimum recycled amounts will be introduced with recycling standards increased in 2035.  All these requirements will be enforced and traced through a system of official digital battery passports.16

Conclusion

The frantic pace of development of new industrial infrastructure and technological advances reflects the challenges associated with rapidly replacing the world’s stock of internal combustion engine automobiles in a sustainable manner.  Technology improvements are lowering the cost of battery energy as well as improving the efficiency of consumer applications, while reducing the use of the most sensitive materials, however EV battery inputs are expected to become increasingly scarce, expensive and therefore suitable for recycling.  

Footnotes

  1. Wood MacKenzie, April 2020.  https://www.woodmac.com/news/opinion/batteries-powering-the-fight-against-climate-change/

  2. Wood MacKenzie, August 2020.  https://www.woodmac.com/press-releases/global-lithium-ion-cell-manufacturing-capacity-to-quadruple-to-1.3-twh-by-2030/

  3. Climate Home News, July 2020.  https://www.climatechangenews.com/2020/07/27/european-battery-gigafactories-boom-despite-covid-slowdown/

  4. Benchmark Mineral Intelligence, April 2020.  https://www.benchmarkminerals.com/membership/coronavirus-supply-chain-shift-was-already-underway-in-battery-industry-2/

  5. TXF News, September 2020.  https://www.txfnews.com/News/Article/7055/EV-gigafactories-Europe-moves-up-a-gear

  6. Fluxpower, August 2020.  https://www.fluxpower.com/blog/what-is-the-energy-density-of-a-lithium-ion-battery#:~:text=What%20is%20Battery%20Energy%20Density,one%20watt%20for%20one%20hour

  7. NTree Technical Paper #10, Electric Vehicles Go Mainstream, February 2021.  https://dl.airtable.com/.attachments/d45e3250c8b256316438df968cc1dcab/bcbb7de3/NTree_TechnicalPaper10_20210210_EVs.pdf

  8. McKinsey, June 2018.  https://www.mckinsey.com/~/media/mckinsey/industries/metals%20and%20mining/our%20insights/lithium%20and%20cobalt%20a%20tale%20of%20two%20commodities/lithium-and-cobalt-a-tale-of-two-commodities.ashx

  9. Volkswagen, June 2020.  https://www.volkswagen-newsroom.com/en/press-releases/volkswagen-increases-stake-in-quantumscape-6136

  10. Argus, January 2021.  https://www.argusmedia.com/en/news/2182042-battery-makers-expand-silicon-anode-production

  11. SAFT.  https://www.saftbatteries.com/media-resources/our-stories/three-battery-technologies-could-power-future/11.   BBC, December 2020.  https://www.bbc.com/future/article/20201217-renewable-power-the-worlds-largest-battery

  12. Energy Storage World Forum.  https://energystorageforum.com/blog/which-emerging-battery-technology-will-be-the-future-of-stationary-energy-storage

  13. Fortum.  https://www.fortum.com/products-and-services/fortum-battery-solutions/recycling/lithium-ion-battery-recycling-solution

  14. Wired, November 2020.  https://www.wired.co.uk/article/electric-car-battery-recycling

  15. Wired, November 2020.  https://www.wired.com/story/the-race-to-crack-battery-recycling-before-its-too-late/

  16. European Commission, December 2020.  https://ec.europa.eu/commission/presscorner/detail/en/QANDA_20_2311

 

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