Aluminum-Air Battery Tech: Powering EVs with Scrap Aluminum

Lateral Thinking To Solve EV Limitations

EVs have taken the car market by storm, with countries like China and Norway already boasting strong market penetration. At the same time, EV adoption has continued to lag in many countries due to a few key limitations:

• Low range for cheaper EV models.
• Slow charging speed, which when combined with regular charging due to low range can make long-distance travel difficult.
• Concern about power grids’ ability to handle the addition of millions of new EVs.

The first 2 problems, range and charging speed, are something the industry is trying to solve with new battery chemistries, as well as a quicker and more dense network of charging stations. But this is still a tough nut to crack. We detailed all the potential avenues for new batteries in our article “The Future Of Energy Storage – Utility-Scale Batteries Tech”.

The grid issues are compounded by the intermittency of renewable power generation. A surge of EVs charging in the evening when people are back home from work and commuting is not welcome when solar power is already out of the picture.

But a new concept could solve all these problems at once. What if instead of choosing between ICE (Internal combustion Engine) & liquid fossil fuel or EV & batteries, we could “refuel” EVs with a fully recyclable fuel?

The Energy Potential Of Aluminum

Aluminum is a very common element on Earth.  In fact, it is actually the most common metal on Earth, ahead of iron, and makes up 8% of the Earth's crust. It is also a metal that requires a lot of electricity for its production, from raw bauxite ore to alumina and then aluminum metal.  This has resulted in Aluminum sometimes even being referred to as “frozen electricity”.

Under its ordinary and placid appearance, aluminum can be a very reactive metal in the right circumstances and has been used in fireworks; aluminum powder was even powering the solid rocket boosters of the space shuttle. In fact, aluminum is 2.5x more energetically dense than diesel or gasoline.  Enter Aluminum-Air batteries.

Aluminum-Air batteries store and produce electricity through the oxidation and reduction of aluminum. It makes the aluminum metal react with air and offers one of the highest energy density of all battery technologies currently available. It can be eight times lighter & four times smaller than Lithium-Ion.

Aluminum-Air batteries are not to be confused with Aluminum-Ion batteries, which are similar to Lithium-ion, just using a different metal.

Source: Energy Post

Aluminum-Air Advantages

As the cathode is just oxygen from ambient air, there is no need for a metallic cathode, making the battery a lot lighter than its competitors.

Another advantage is that it is essentially an “electric engine” consuming aluminum instead of oil and does not lose voltage when discharging like battery systems do.

The limitation is that this consumes aluminum and cannot be recharged by just plugging the battery. So, it is more similar in its principles to a common AA battery than to a lithium-ion battery. Thus, it requires a system for a battery swap, taking around 90 seconds, instead of a liquid fuel refueling or a 10-15 minute electric recharge.

An alternative can also be to use a mix of Aluminum-Air batteries + rechargeable batteries, allowing for flexible use of direct recharge or aluminum-powered drive depending on need, similar to a hybrid vehicle, but without any fossil fuel.

Infrastructure Pros

A strong element in favor of Aluminum-Air batteries is that there is already a well-established, efficient, and scaled-up industry for aluminum recycling—something still direly missing from Lithium-Ion batteries.

It also means that for sourcing the base material, the Aluminum-Air battery industry could source its material from scrap aluminum salvaged from old buildings, machines, or airplanes and generate power simultaneously. Overall, the system requires no critical/polluting/expensive resources like lithium, nickel, cobalt, or rare earth minerals.

As mentioned above, the battery swap also means that there is no pressure on the power grid for the recharging to be done instantly when the EVs are coming to the recharging/fuel station. Instead, the regeneration of the aluminum and recharge of the batteries can be done with renewable energy when it is produced in surplus.

Lastly, not only can aluminum metal be regenerated with green power when convenient, but it can also easily be stored away without much cost, as it is a stable and nontoxic solid metal that does not oxidize much. So, energy can be stored through aluminum stockpiles for long periods of time, at a much lot lower storage cost than with batteries, ammonia, or hydrogen.

The bulk transportation of aluminum also does not require specific infrastructure like hydrogen does and can be done by ordinary trucks or trains.

Aluminum Cost- Source: RiAlAiR

Aluminum-Air Batteries Cons

A limitation of Aluminum-Air batteries is the need for a dense network of battery-swapping stations. Due to the problem of lack of standardization of EVs and the costs of building a dense enough network, battery swapping has often been a failed idea. This is even less likely to succeed for traditional battery concepts, as the EV industry is moving toward “structural batteries” that are integrated into a vehicle frame

Some companies (see below) are working on the battery swap for aluminum-air batteries to be doable by hand, greatly reducing the technological complexity and need for an expensive battery swapping station, with simpler delivery automates, like for propane bottles, enough to do the job instead.  In any case, an infrastructure for collecting and rebuilding/recharging the spent batteries will need to be put in place.

Overall, the concept is not new and was first envisioned in the 1960s. At the time the toxicity of the electrolyte blocked the progress of this technology. Other technical issues can be significant as well, mostly related to the air cathode:

“The sluggish efficiency of the oxygen reduction reaction is the barrier for its application. Other problems include CO2 reaction with alkaline electrolyte producing carbonate precipitates, water evaporation to open air [electrolyte dry-out] and electrolyte penetration into the pores of the air cathode.” – Source: Automotive Logistics

Aluminum-Air Companies

1. Aluma Power

Aluma Power is a Canadian company located on Aamjiwnaang First Nation lands.

Aluma Power envisions a full cycle efficiency of 43% and 700% efficiency when aluminum is first used for other applications like building the frame of cars, buildings, airplanes, greenhouses, boats, etc., before being recycled into fuel.

Source: Aluma

Aluma Power's unique approach is to focus on a mechanical method to mitigate the limitations of Aluminum-Air batteries, like anode corrosion and wear, by rotating the anode. This design can use any scrap aluminum, including melted engine blocks or soda cans. It is documented in the US Patent US10978758B2.

The fuel disk can be changed in a few minutes and lasts up to 130 hours of consumption.

Source: Aluma

The company claims that its disk system allows for 70% fewer capital costs than incumbents and lower labor costs for “storage as a service”.

2. Métalectrique SAS & MAL Research & Development

Métalectrique in France and its subsidiary in the UK MAL are developing Aluminum-Air batteries. The key IP of the company is a proprietary electrolyte chemistry that is claimed to reduce the problems of anode corrosion and pore blockage.

The company’s website is a little bare, with mostly some news article links and the announcement of a future product release in 2024. This could be a little concerning, considering a previous announcement for a launch in Q4 2021.

The company seems to focus on 3 different product concepts:

• A 300-mile range extender for EVs, something in discussion with 2 very large automotive companies.
• A 1,500-mile range EV battery. MAL has signed a multi-million-pound deal with Austin Electric for mass-producing these batteries in the UK.
• £3,500 conversion kits turning regular fuel cars into hybrids.

MAL claims the manufacturing of its battery costs only $36/kWh compared to around $180/kWh for Lithium-Ion batteries. When including the battery amortization, it would bring the cost of driving to £0.08/mile, instead of £0.50/mile for Lithium-Ion.

The technology could also be applied to planes, defense batteries, and remote power on islands.

3. RiAlAiR

The company is focused on producing Aluminum-Air batteries for the boat and fishing industry. The company offers a subscription service for its batteries, reducing the upfront costs and helping reduce pollution and high fuel costs.

The focus on professional boat users like fishing boats and taxi boats means that the economic argument of cheaper fuel can hit home well, and the business case does not need to rely on green energy arguments, but simply on increased profitability.

The switch from fossil fuel to an electric-powered boat also opens the possibility of supplementing the energy supply with solar panels or wind turbines on the boat itself, increasing even further the fuel economy and the autonomy of the boat.

Source: RiAlAiR

Lastly, an electric power train is more efficient for boat propulsion, with 92% of the energy converted into thrust, instead of just 35% for fuel-powered boats (the difference comes from thermal and mechanical losses in ICE engines).

Currently, millions of fishing boats are consuming 50 billion liters of fuel per year, making 1.2% of the global fuel consumption, with the majority with a tonnage below 20 tons and less than 12 meters in length, mostly located in Asia. There are also 15 million recreational boats that have the potential to be switched to greener electric propulsion.

Source: RiAlAiR

While electric propulsion has been a non-starter for boat propulsion, the limitation has always been the energy density of the batteries. This is something that modern Aluminum-Air designs could solve, potentially creating a niche but profitable market for these batteries.

4. Phinergy (PNRG.TA)

Phinergy is the only company involved in Aluminum-Air technology we could find that is also publicly listed. The Israeli company is developing both aluminum and also zinc-based batteries. It is targeting the market of power backups, mobility/EVs, and energy storage. It is also looking at the potential for marine energy, with container-ized batteries.

The company recently signed an agreement to provide 300 power backup systems to Indian telecom company Indus Power, as well as a successful test with Cellnex, another telecom company. It is also testing its system with a leading cloud data center company.

It also showed a prototype electric Tata passenger vehicle in January 2023. India is at the center of the company's export strategy, having signed an agreement for building an ecosystem with Hindalco Industries Limited, one of India’s largest aluminum manufacturers.

5. Log9

This Indian company is the first indigenous Lithiuim-Ion battery cell manufacturer, which also produces its own battery management system. The company produces batteries, graphene ultracapacitors, and Aluminium-Fuel-Cells (AFC).

The company was reported in 2020 to have a team of 45 people working on Aluminum-Air batteries. It also discussed a prototype for a last-mile delivery vehicle able to perform 3,000 km on a single “charge” in 2021.

More recently, the company seems to have mostly focused on fast charging Lithium-Ion batteries, so it is not clear if its goals for Aluminum-Air are being achieved, but the technology is still featured prominently on its website home page.

Conclusion

Aluminum-Air batteries, or maybe aluminum fuel cells would be a better term, are a very interesting alternative to the conventional approach to EV and battery technology.  By providing a metallic solid fuel, it could circumvent most of the obstacles to EV adoption, as well as solve the problem of managing the intermittence of renewable energy by “storing” it in recycled solid aluminum.

For now, the technology is still in its infancy, with none of the largest corporations or battery companies seemingly working on it.  This is partly due to the concept radically departing from conventional wisdom in the EV industry and would require a completely different skill set and manufacturing processes.

It is also because the technology tends to fall through green policies and subsidies, matching neither the requirements for hydrogen fuel-cell technology nor for the rechargeable batteries/EV policies. It seems to be the most welcomed in India, with the country eager to catch up with China in battery technology and green energy.