Zinc based battery technology for electric vehicles

Zinc (Zn) batteries date back to Edison’s time who patented one back in 1901. However, Zinc based batteries have been thought of as disposable for decades because they have always resisted recharging due to formation of sharp destructive spikes, known as dendrites, that lead to short-circuiting and ultimately destruction of the battery.

This article talks about upcoming 3D Zinc Sponge Battery technology, that claims:

– Equivalent performance to Li-ion batteries

– At half the price of Li-ion batteries

– Approx. half the mass and volume of Li-ion batteries

– Complete fire-resistance

– Made from 100% recyclable low-cost materials

– Pose no resource supply risk as materials are abundantly available in India

3D Sponge Zinc

The problem with poor rechargeability of Zn batteries has recently been solved by the patented redesigning of the Zn electrode as a monolithic, porous, aperiodic structure in which an inner core of electron-conductive metallic Zn persists even to deep levels of discharge.

Zinc, when converted to an open cell sponge form (referred to as 3D Sponge Zinc), becomes a continuously wired structure, preventing the formation of dendrites.

Alkaline (non- toxic) batteries based on a 3D Zinc anode (with silver oxide, nickel oxyhydroxide, or air cathode) offer a structural solution to the zinc electrode that enables an uninterrupted flow of current during charge and discharge, obtaining cyclic (recharging) durability.

Zn batteries
Battery Performance with different form factors of Zn

Technology Development and Future Plans

The technology is jointly developed between the US Naval Research Laboratory and EnZinc Inc. The team has invested over 15 years of R&D on the tech that is now being commercialised by EnZinc. EnZinc has partnered with SIMPAL who have secured exclusivity for production & distribution of the batteries throughout SAARC. SIMPAL are looking to form collaborations for a Make In India initiative to begin immediately. 

The technology is currently at TRL 5 / TRL 6 as per rating allocated by the US Department of Defense & NASA. (TRL – Technology Readiness Level)

Comparison with Prevalent Batteries

Speaking to EVreporter.com, Sauman Das Gupta – Director of Technology at SIMPAL mentions that 3D Zn based battery technology offers the energy of Li-ion batteries at the cost of lead-acid batteries and is safer than both. He says that Indians were the first civilization to discover the unique properties of the element Zinc back in the 6th Century BC.

3D-Zinc-volume-comparison
A portrayal of space saved in a naval vessel when 3D Zinc batteries replace conventional lead-acid batteries used in the onboard UPS. 

“With two redox electrons and low polarizability, Zinc offers what electro pioneer Alessandro Volta originally saw as superior electrochemistry with high specific capacity and power. We are ready to showcase 3D Zinc battery chemistry with a Nickel-based cathode (i.e. Ni-3D Zn battery) with an aqueous electrolyte and polythene separator. The manufacturing process is similar to that of the Lead-Acid battery production line that will allow rapid adoption with minimum capital investment. Unlike Lithium-based technology, there are no expensive cleanroom requirements that mandate a specialist workforce. 3D Zn batteries offer a completely environmentally friendly alternative that does away with all toxicity being introduced to the environment as happens with all other existing energy storage solutions today”, says Sauman.

Applications of 3D Zinc Battery Technology

For EV applications in all vehicle segments, Ni-3D Zn batteries claim to offer a much safer alternative with at least an equivalent cycle life of existing Lithium-ion at a much more economical price. The batteries can work safely in a temperature range of -200 to at least 600 C, eliminating the need for an expensive thermal management system that is necessary for most storage technologies.

“There also lies an opportunity in replacing Lead Acid based battery technology completely including SLI (Starting, Lighting, Ignition) batteries that are found in all vehicles including ICE and EVs. When compared to Lead Acid batteires, 3D Zinc based batteries are lighter, compact (1/3rd the weight, size and volume) and have 4-5 times the life span. We have demonstrated in-laboratory SLI applications with up to 54,000 plus cycles at 4% Depth of Discharge”, adds Sauman.

Sauman mentions that the scope of this technology is applicable to both mobile and stationary applications, i.e. from IoT and wearables to the Grid and space-based colonies. 3D Zinc anode based batteries have form factors that can go from micro batteries to 60MW applications.

The technology has received multiple accolades in India & Internationally, including recognition during MOVE Summit 2018 and Clean Tech to Market (C2M) by UC Berkeley Haas in December 2019. You may download a white paper about the technology that was selected by India SmartGrid forum for energy utility week 2019.

Keep watching this space for more updates! For any enquiries and further information on the technology, please leave a comment.

Note – This article is second in the series dedicated to exploring upcoming battery chemistries for EV applications, that can potentially serve as alternatives to Lithium-ion batteries. For the first part of the series, read about the promise shown by Sodium-ion battery research.

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