Chapter 3. Energy Conversion and Minerals Used for Materials
A. Secondary cells and core mineral materials
in a few regions around the world, the abundance of these reserves suggests that there is less a possibility that silicon metal availability will pose a threat to the quantitative supply of materials than a sudden disruption in supply. However, both the fact that silicon metal is produced in high-purity quartzite mines, and the fact that there is such a heavy reliance on China signifies a very high supply risk.
According to the outlook on silicon metal prices illustrated in Figure 3-21, silicon metal prices are expected to decline and stabilize; therefore, the possibility of any problems related to the silicon metal supply, from an economic perspective, is very low. However, China, a major importer of silicon metal, is continuously strengthening its environmental regulations. Given that electricity costs account for the largest share of production costs, increased electricity costs—resulting from changes in the power mix due to stricter environmental policies—may impact production costs. Changes in silicon metal prices may influence polysilicon prices to a certain degree62, but the impact of silicon metal prices on PV system prices is estimated to be less than 1%.
Therefore, fluctuations of silicon metal prices are not expected to have a large impact on the proliferation of PV systems.
2. Secondary cells and materials
분리막 Separator
양극과 음극의 접촉을 차단하는 역할 Separates positive electrodes from negative electrodes so that there is no contact between the two.
전해액 Electrolyte
이온이 원활하게 이동하도록 돕는 매개체 A medium that enables the ions to move efficiently.
양극 Positive electrode
리튬이온 소스로 배터리의 용량과 평균전압을 결정
Source of lithium ions. Determines battery capacity and average voltage.
음극 Negative electrode
양극에서나온 리튬이온을 저장했다가 방출하면서 외부회로를 통해 전류를 흐르게 하는 역할
Stores and then discharges lithium ions from positive electrodes and enables electric currents to flow through an external circuit.
The negative electrode stores and discharges electrons from the positive electrode and generates power. The medium that enables the electrons to move freely is the electrolyte. However, if the positive and negative electrodes make direct contact and the electrons do not move, the battery generates heat but no electricity. This is why a separator is needed to separate the two electrodes and enable only the electrons to move. Lithium ion batteries, which are now widely being used, are secondary cells made of positive active materials based on lithium.
There are many types of lithium ion batteries, whose positive electrodes all have different characteristics.
Table 3-2. Types of Lithium Ion Batteries
LCO LMO NCA LFP NMC
(111)
NMC (811) Content*
(kg/kWh)
Lithium 0.11 0.09 0.10 0.08 0.13 0.10
Cobalt 0.90 0.13 0.35 0.08
Nickel 0.69 0.35 0.64
Stability High High Low Very
high
Somewhat
high Somewhat high
Disadvantages Price Lifespan Stability Density Price Improvements※ Advantages Lifespan Price Density Stability Density Improvements※ Major fields of
application
Small home appliances
Medium- sized home appliances
All fields
Domestic demand in China
All fields All fields
*Source: BNEF (2017a) p.22.
※ Compared to the NMC111 series.
The most widely used type of lithium ion battery is NMC (Lithium Nickel Manganese Cobalt Oxide) and LFP (Lithium Ferrophosphate), which is most actively being produced in China. NCA (Lithium Nickel Cobalt Aluminum Oxide) batteries, used by Tesla, have also been widely used since the introduction of cylinder secondary cells by the Panasonic 18650. The positive electrodes of each battery type have specific characteristics.
NCA is the oldest form of lithium ion battery and has a high density but low stability. In contrast, LFP has high stability and is cost effective, but its low density makes it heavy. Of all the lithium battery types, NMC boasts the most developed technology. This type of battery is known for its high performance and is backed by continued technological developments, with increasing energy density. The basic materials used to make lithium batteries are lithium (a fundamental component), nickel, and cobalt. For NMC lithium ion batteries, the ratio of nickel, manganese, and cobalt was originally 1:1:1, but since cobalt is relatively expensive, this ratio is gradually being reduced to 6:2:2 and 8:1:1.
In the past, lithium ion batteries were often used in cellular phones. In comparison to cell phones, EV proliferation will require an astronomical amount of lithium. As illustrated in Table 3-3, it takes less than 5 g of lithium carbonate to produce an iPhone 8, but around 8,000 times more lithium to manufacture one EV.
Table 3-3. Types of Lithium Ion Batteries
iPhone 8 Tesla Model S Hyundai Kona
Battery weight 26g 530kg 453kg
Battery capacity 6.96Wh 75kWh 64kWh
Basic lithium carbonate contact* Around 4.8g LCE Around 40kg LCE Around34kg LCE
Battery type NMC NCA NMC
*Photos selected by the author from manufacturer websites. Figures calculated by the author based on public data.63
Research is currently being conducted to procure mineral alternatives to lithium, such as vanadium and natrium, but in most cases, batteries made using these minerals are better suited for large-scale storage devices, as opposed to portable batteries, or have limited commercial viability. Lithium-based battery technology is also still under development. The IEA forecasts that the NMC811 battery, currently being developed, will become a major battery technology in the market by 2030, as seen in Figure 3-26. Overall, there is a rising interest in securing major mineral materials for lithium ion batteries.
Figure 3-26. Outlook on the Commercial Viability of Developing Battery Technologies
Source: Recitation of IEA (2018) p.66, ((IEA analysis based on Meeus (2018); Nationale Plattform Elektromobilitat (2016); NEDO (2018); Howell (2016); Pillot (2017)).
Of the main lithium ion battery materials, this study will focus on lithium and cobalt, the two minerals that have the most concentrated production volumes and the greatest price fluctuations.
63Product images (https://images.apple.com/legal/more-resources/docs/apple-product-information-sheet.pdf), (https://teslamotorsclub.com/tmc/threads/wk057-tesla-model-s-battery-weight.106143/),
(https://pushevs.com/2018/03/29/2019-hyundai-kona-electric-gets-estimated-epa-ratings/), accessed on each website on July 22, 2018.