A lithium alternative and silicon anodes promise better performance.
Current lithium-ion battery technology is limited by physics and economics. Lithium-based batteries are heavy, expensive to produce and are relatively slow to charge. A new silicon nanowire anode technology developed by Amprius Technologies promises to deliver lithium-ion batteries with double the gravimetric and volumetric power density of current systems. The solution to the cost problem is to use an alternate battery chemistry. BYD battery business unit FinDreams plans to do just that with the first large-scale sodium ion battery production plant, planned for Jiangsu province in China. Sodium ion batteries are lower in performance, but are much more cost-effective compared to lithium alternatives.
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Episode Transcript:
This week is all about two developments in electric vehicle battery technology.
Lithium-ion technology is now standard in the electric vehicle industry, but it’s not without limitations. Charging is still slow, and fast charging has negative consequences for battery life. The batteries are heavy, expensive and rely on resources like lithium which are in short supply relative to anticipated demand. Correcting these issues is essential, and R&D is ongoing worldwide.
Two noteworthy recent developments involve materials and a core technology to EV batteries: electrodes. Fremont, California based Amprius Technologies has announced a lithium-ion battery using silicon nanowire anodes, which the company claims will give its lithium-ion cells an unprecedented energy density of 500 Wh per kilogram. The firm states that they can deliver cells with half the weight and volume of current commercial lithium-ion products.
The combination of high energy density by both mass and volume suggests that the silicon nano wire cells will be useful for weight-critical applications such as aircraft and VTOL platforms like air taxis and helicopters.
Amprius plans to build a 774,000 square foot facility in Brighton, Colorado with up to 5 gigawatt-hours (GWh) of manufacturing capacity.
While lithium-ion technology currently dominates the EV space, it’s not the only possible chemistry. Sodium ion batteries are an alternative that eliminates the problem of limited lithium supplies, although with a performance penalty compared to lithium chemistries.
A major advantage of sodium ion designs, however, is cost, and Chinese automotive giant BYD has announced a joint venture to begin mass production of sodium ion batteries for EVs. BYD’s battery making venture, FinDreams, has inked a deal with Huaihai Holding Group to build a mass production sodium ion manufacturing plant in the Jiangsu province of China. FinDreams will spearhead production, while Huaihai will handle sales and marketing of the batteries to global automakers.
The combination of lower energy density and lower cost also suggests a lower range, and it’s widely expected that sodium ion batteries will be used primarily for small, urban vehicles that can be charged frequently.
Ironically, China holds a major proportion of the world’s lithium supplies, but does not have a strong supply base in the sodium carbonate soda ash used to produce sodium metal.
The high price of batteries is a known factor in the slow adoption of electric vehicles worldwide, along with the lack of a widespread charging infrastructure. As charging stations proliferate, however, driving range for urban and suburban users becomes less important, opening the door for lower range but lower cost sodium ion equipped cars.
If this technology can lower the cost of EV’s sufficiently that middle-class American households can add one to the existing ICE family vehicle fleet, the change in commuting patterns may create a positive feedback loop of more demand for charging, resulting in more charging stations, which will drive demand for EVs of all types.
