As the sun sets on your solar energy installation, don’t be surprised when the power stays on, thanks to a new flow battery based on Zinc-air chemistry.
As we’ve reported before, energy storage is the key to unleashing the full potential of renewable energies by balancing their shortcomings: the variable output and the mismatch between peak power generation times and peak demand. So energy storage is becoming a huge market, with the requisite array of competing technologies. We’ve covered some of the challenges of Li-ion batteries, what may be considered a leading contender. For large-scale applications, Li-ion batteries must overcome challenges associated with degradation, current and temperature management—and an unacceptable risk of operational failure.
As a result, many companies are eyeing flow batteries as a promising adjunct for solar, wind and other renewable energies. Unlike solid-state batteries, flow batteries store energy in electrolytes which can be pumped in and out of tanks, providing high power output, large energy storage capacity, and the ability to switch between charge and discharge modes quickly. Now out of Vancouver, B.C. arrives a new alternative targeted for long-duration applications like solar power storage. By using atmospheric oxygen, the ZincNyx zinc-air technology needs just one storage tank—much like a fuel cell—resulting in a more simple, compact and scalable flow battery.
ZincNyx began operations in 2012 by acquiring the intellectual property assets of a prior company, Metallic Power Inc. (MPI), which had spent over seven years investigating zinc-air chemistry. ZincNyx has built on this technology with its own team of electrochemists, mechanical engineers and product specialists. This team collaborates with researchers from academia including University of British Columbia, Simon Fraser University, Queen’s University (Kingston), INRS (Montreal) and AzRISE at the University of Arizona. The research and development efforts have been assisted by a grant from Sustainable Development Technology Canada (SDTC).
Interestingly, Canadian natural resource giant Teck Resources Ltd. is the primary investor in ZincNyx. Teck sees broad implications in this technology for how society generates and uses energy.
The ZincNyx flow battery comprises three subsystems: zinc regeneration, fuel storage, and power generation. Each subsystem presented its own development challenges:
- The zinc regeneration subsystem needs to grow a substantial amount of zinc particles efficiently, and to release those particles from their growth site reliably. ZincNyx accomplished this by growing dendritic particles on magnesium plates and washing them off with electrolyte flow.
- The fuel storage subsystem contains the zinc particulate suspended in a KOH electrolyte. It must allow the zinc particles to settle during long periods of standby time, and then quickly fluidize them when power is required. To accomplish this, the subsystem creates a fluidized zone near the bottom of the fuel tank where fresh electrolyte is injected into the particle bed.
- The power generation subsystem has to capture a sufficient quantity of zinc particles to drive the oxidation reaction, while also permitting the reaction products to be removed from the cell. ZincNyx includes an array of “catchers” in its fuel cells that promotes the formation of a semi-porous anode bed of particles.
Unlike conventional energy storage systems, the ZincNyx system operates similar to a fuel cell, so users can increase the energy capacity (kWh) of the system simply by enlarging the fuel tank. The separation of the power generation and zinc regeneration functions makes it possible to configure the discharge power and recharge power separately. For these reasons, ZincNyx is confident the system can fit a wide range of applications between 5kW and 1MW.
Using only zinc and air as fuel, the system is inherently safe and environmentally friendly to manufacture. By eliminating the separate fuel tank for oxygen, the system becomes simpler to build and maintain, and it doubles down on energy density.
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