Zinc based energy storage systems for electric vehicles

Zinc based energy systems have tremendous advantages: High specific energy, recyclable, safe use, zero emissions and local supply. Performance, market and economic factors are creating opportunities for these systems. The time has come for zinc energy systems. In addition to priority research, including life cycle analysis, the Consortium will develop generic technical and marketing tools such as brochures, a website and materials for presentation.

Current membership of the ZESTec consortium includes zinc energy system manufacturers (eVionyx, PowerAir, PowerZinc, S.C.P.S.) and zinc producers (Grillo, Industrias Peñoles, TeckCominco, Umicore, Xstrata and Zinifex). New members are welcome. The activities of the consortium are being coordinated through the International Zinc Association.

Key minerals used to create lithium batteries may not be sufficient to meet future demand for plug-in hybrid and electric cars, more effort should be focused on zinc air.

The vast majority of world’s supply of lithium carbonate, the mineral used to make lithium-based batteries for cellphones and laptop computers is found in just four countries: China, Chile, Argentina, and Bolivia, reports William Tahil, director of research for Meridian International Research in a newly released white paper entitled, The Trouble with Lithium.

Zinc based energy systems have tremendous advantages including high specific energy, recyclability, safety and zero emissions. Its not surprising then that zinc is used in the manufacture of a variety of battery chemistries, both primary and rechargeable, consumer and industrial.

The most well known of these chemistries are the primary zinc-carbon and alkaline batteries, which together dominate the standard AAA, AA, C and D size consumer battery market.

Zinc/Air and Zinc/Silver batteries are also widely used in the electronics industry to power hearing aids, wrist watches, calculators and the like. Industrial Zinc/Silver and Zinc/Nickel batteries are of critical importance in a variety of aeronautic and military applications; while larger Zinc/Air cells have been developed to power electric vehicles and Remote Area Power Supply (RAPS) installations.

The zinc air cell is a particularly interesting technology because it acts as a partial fuel cell using the O2 from air as the cathode. There are portable primary zinc/air batteries and industrial primary zinc/air batteries. There are also electrically rechargeable zinc/air batteries that use a bifunctional oxygen electrode for charge and discharge, and mechanically rechargeable zinc/air batteries that require the replacement of discharged anodes.

Zinc + Air = Energy

The Trouble with Lithium -Implications of Future PHEV Demand for Lithium Supply and Resources

Lithium Ion batteries are rapidly becoming the technology of choice for the next generation of Electric Vehicles – Hybrid, Plug In Hybrid and Battery EVs. The automotive industry is committed increasingly to Electrified Vehicles to provide Sustainable Mobility in the next decade. LiIon is the preferred battery technology to power these vehicles.

The alternative battery technologies of ZnAir and NaNiCl are not resource constrained and offer potentially higher performance than current automotive LiIon technology. Research and industrialisation of Electrified Vehicles should also prioritise these alternative battery technologies.

The Zinc-Air Solution – Why the Automotive Industry Must Adopt Zinc-Air Technology to Overcome Peak Oil and Global Warming

Oil Demand must be reduced greatly over the next 10 years in line with declining oil supplies and to reduce CO2 emissions. The only practicable way to achieve this is to electrify Road Transport and replace petroleum with Electric Propulsion. The Lithium Ion battery has become the prime candidate to power electrified road vehicles in the near future.

Lithium supply and future production will be far from adequate to sustain global electric vehicle production. The current focus on LiIon batteries to the exclusion of all other batteries is a grave error that will lead to EV and PHEV production quickly becoming uneconomic due to insufficient Lithium supply.

Instead, the Automotive Industry should adopt the Zinc Air Battery and Fuel Cell technologies. Zinc Air Batteries have the highest specific energy and lowest cost of any Electric Vehicle rechargeable battery technology and are therefore well suited for mass market introduction in millions of electric automobiles. The Zinc Air Fuel Cell has even higher specific energy than the ZnAir Battery. The ZnAir Fuel Cell is the only electric propulsion technology that could forseeably permit very quick recharge times comparable to refuelling a conventional vehicle with petrol. Due to its low weight, ZnAir technology is the only viable contender to power large trucks and heavy commercial vehicles which would require batteries 10 times as large as a car.

Zinc production is the third or fourth highest of all metals – it is therefore the cheapest and most abundant battery metal. Indeed, Zinc is the only metal which can sustain large battery production in the volumes required by the Global Automotive Industry (apart from sodium beta batteries – see below).

Zinc Air batteries must be equipped with a filter to absorb CO2 from the entry air. Therefore vehicles equipped with this technology can be designed to permanently reduce atmospheric CO2 levels, contrary to conventional vehicles.

In light of the logistical, temporal, environmental and financial constraints with which the world is faced, National Governments should prioritise the development of Zinc Air Battery powered automobiles and the development of a refuelling infrastructure for Zinc Air Fuel Cell powered commercial and utility vehicles. A “Zinc Economy” using already available and simple technology presents a viable, practicable and quickly implementable path for society to transition from oil power to renewable electric power, to maintain the essential transport infrastructure on which society depends and lay a foundation for further more advanced developments in Electric Propulsion technology to follow.

Zinc-Air Technology Notes

ZnAir technology has always been attractive due to its very high specific energy and very low cost. Set against this has been its low specific power, low cycle life and need for carbon dioxide absorption.

Zinc Air chemistry has been studied on and off as an EV power source since at least the 1950s. Leesona Moos developed a rechargeable ZnAir EV battery in the 1960s for city car use. At 140 Wh/kg, a 230 kg battery provided 31 kWh capacity and 160 miles range at moderate acceleration capability. Cycle life was only 100 cycles to 100% DoD.

By the mid 1970s, the French Compagnie Generale d’Electricite had developed a tubular cell ZnAir system that could either be recharged electrically or hydraulically. Practical energy density of 110 Wh/kg, at a specific power of 80 W/kg and 500 cycles was projected.

By the early 1990s, the leader in ZnAir development was Dreisbach ElectroMotive (DEMI). In 1991, their converted Honda CRX equipped with a nominal 50 kWh battery pack demonstrated 150 Wh/kg specific energy in an SAE "D" suburban cycle test. The car operated for 215 miles at 45mph, with a 20 mile reserve still available. At 65mph, range was projected to be 150 miles. At 30mph, the car would have a range of over 300 miles. Cycle life did not progress much beyond 100 cycles or a two year life.

Later in the 1990s, Evercel’s Nickel Zinc technology showed very promising improvements in cell cycle life, to 600 cycles 100% DoD at C/2 for both charge and discharge. Lawrence Berkeley’s flowing electrolyte ZnAir system also achieved 600 cycles but only at C/4. Ni-Zn anode technology is directly transferable to ZnAir. In the late 90s, PSI in Switzerland were also making promising progress in air cathode development and power density improvement, while maintaining cycle life. The German company Zoxy tried to commercialise this without success.

While the leader in ZnAir fuel cell technology is currently Electric Fuel/ Arotech in Israel, the country in which the SOLZINC solar thermal reactor is also being tested, commercialisation of their technology for EV applications has stalled. A number of smaller US and Taiwanese technology development firms are trying to develop ZnAir fuel cell systems and Teck Cominco have bought the rights to Metallic Power’s technology. However, overall ZnAir technology development is attracting little funding or interest due to the overriding focus on Lithium Ion technology.

The Zebra Battery

In 1998, Mercedes Benz were on the point of launching an all-electric version of the A Class small car. Powered by a 30 kWh Zebra battery weighing 370kg (including control system), the vehicle was claimed to have demonstrated a real world range of 120 miles. A fleet of 16 A Class cars tested the Zebra battery in all weather conditions – some of these vehicles are still being used by Mercedes today.

Improvements in Zebra technology since then have reduced the weight of a 30 kWh unit to 270kg (120 Wh/kg). This specific energy is superior to any automotive LiIon battery available or under development today.

The Zebra battery is suitable for pure BEVs and could be used for PHEVs. It is not suitable for power assist hybrids (HEV0).

The history of Zebra development dates back to the 1970s. The technology was first developed in South Africa. By the 1990s, there were some 8 companies developing sodium beta batteries and 4 pilot production plants were in operation. Today, only MES-DEA in Switzerland manufacture the Zebra battery, although sodium sulphur is still undergoing extensive development by NGK for stationary applications in Japan. A numbre of test installations are in operation.

As a "hot" battery, ambient temperatures have no effect on battery performance. In sub-zero winter temperatures, a Zebra powered EV will deliver as much power and energy as in mid-summer. This temperature independent capability is a unique feature of "hot" batteries such as the Sodium beta variants (Sodium Sulphur and Sodium Nickel Chloride).

The Zebra battery NaNiCl technology makes far more use of cheap and readily available materials than LiIon and NiMH. The major active materials are nickel, iron and common salt, along with some aluminium. The separator is ceramic beta alumina, a very inexpensive material. The case is made from stainless steel. The only potentially limiting active material is nickel, although MES-DEA state that less than one third as much nickel is required per kWh as NiMH (1.53 kg/kWh compared to 6.8 kg/kWh for NiMH). Cycle life of over 1400 nameplate cycles has been demonstrated in well over 10 years testing. The battery has a 10 year calendar life.

If nickel availability becomes constrained, Zebra technology has the potential to be developed into an even lower cost variant that would use little or no nickel – the Sodium Iron Chloride battery. This has an open circuit voltage of 2.35V against 2.58V for NaNiCl, but could be manufactured in unlimited quantities from very cheap and ubiquitous active materials (iron and common salt). Specific Energy would only fall by 9% and battery operating temperature could be reduced. We have stated before that development of this NaFeCl battery technology should be prioritised, with the prospect of developing an extremely inexpensive, rugged and high specific energy battery that could approach a cost of $100/kWh and enable widespread adoption of BEVs and PHEVs.