NY BEST: Metal-Air Batteries

March 2012

The Big Picture

• De-linking of supply and demand to avoid peak energy and capacity cost

• Greater profitability and adoption of renewable generation

• A means for retail electricity customers to reduce cost

• Electric vehicles that are cost competitive with gasoline-powered cars

Current energy storage technologies are too expensive to compete with existing solutions

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Goal: Produce energy

storage tech with the cost and specs to beat

current solutions

Storage solution value creation:

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The Challenge

De-linking of supply and demand on the grid • Cost must be less than marginal generation (low cost/long life)

• Also lower cost/more flexible than transmission and distribution infrastructure

• Must have good total efficiency (power in vs. power out)

Greater profitability & adoption of renewable generation • Cost + Efficiency +Long Cycle Life

A means for retail electricity customers to reduce cost • Cost + Energy Density + Safety + Efficiency

Electric vehicles that are cost competitive with gasoline cars

• Cost + Energy Density + Safety

Promising energy storage applications and corresponding battery characteristics:

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Why Metal-Air?

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Vs

Metal Air provides highest potential energy density for batteries

Energizer, Zinc Air Prismatic Handbook

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History of Metal Air Batteries

5 Marta Baginska ,NPRE 498 Energy Storage Systems, Dec 2011

Characteristic Data of Metal Air Cells

6 confidential

Metal Anode

Electrochemical equivalent of metal

Ah/kg

Theoretical cell voltage with O2 electrode, Volts

Theoretical specific energy of metal-O2

couple, Wh/kg

Practical operating voltage metal-O2

couple

Lithium 3,861 3.3 12,741 2.4

Calcium 1,337 3.4 4,547 2

Magnesium 2,205 3.1 6,837 1.4

Aluminum 2,980 2.7 8,046 1.6

Zinc 820 1.6 1,312 1.1

Iron 960 1.3 1,248 1

Cadmium 478 1.2 572 0.9

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Reproduced from Barin Y. (1989) Thermochemical Data of Pure Substances Weinheim: VCH and Linden D (1984) Handbook of Batteries and Fuel Cells

Battery Systems

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Choosing Metals for a Battery System

High Energy Density React with moisture, non-aqueous

solvents needed, poor plating, capacity fading, expensive, limited world supplies

High cell voltages Poor cycling, corrosion

Good plating, inexpensive, low corrosion

Dendrite formation

Lithium, Sodium, Calcium

Magnesium, Aluminum

Iron, Zinc

Advantages Disadvantages

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Zinc: Plentiful and Reliable

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• Zinc: Inexpensive

High energy density

Safe, non toxic, non flammable

Environmentally friendly, recyclable

One of the world’s most plentiful metals

• Zinc is produced at 11 mines in 6 US states: New York, Alaska, Idaho, Missouri, Montana, and Washington

• US has 35% of the world's zinc reserves, but <1% of known lithium reserves

Machine Design

Primary Zn-Air batteries used for years

Initially used as large batteries for applications such as

railroad signaling, remote communications, and ocean navigational units requiring

long term, low rate discharge

With development of thin electrodes, these systems are

used in small, high capacity primary cells, such as for hearing

aids, small electronics, and medical devices

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Why use high pH, alkaline, aqueous electrolyte?

• Air electrode performs better in base

• Good electrolyte conductivity

• Wider choice of catalysts and current collectors

However, the penalties are:

• Carbonation (CO2 from air) forms insoluble carbonates which block air electrode

• Non-uniform zinc deposition (dendrites)

• Caustic electrolyte

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Eos’ Proprietary Problem/Solution Portfolio

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The Problem Eos Solution

• Air electrode clogging due to carbonate, as a result of CO2 absorption with traditional KOH electrolyte

• Novel aqueous electrolyte with near neutral pH

• Rupture of ion-selective membrane due to dendrite formation of Zn metal, caused by electrolyte and wear and tear over time

• No membrane required and electrolyte is non-dendritic

• Electrolyte drying out over time as oxygen enters • Electrolyte management system and self-filling/healing

system design

• Zinc electrode changes shape due to expansion from the change in density from zinc metal to zinc oxide

• Electrode maintains integrity and shape during charge and discharge cycles

• Zinc corrodes due to inefficient plating • Proprietary additives optimize zinc plating

• Materials degradation/corrosion over time • Selection and proprietary treatment of materials

• Cell ionic and electrical connection failure • Integral and redundant electrical and ionic connections

Comparison of Voltage Profiles: Zinc Air Cells Cycled in Eos’ Near Neutral Aqueous Electrolyte and in Alkaline

KOH electrolyte

• Identical Cells and Test Protocols

• Two Different Electrolytes

• Note: Cells using Eos’ electrolyte have higher discharge voltages and lower charge voltages

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Important: No signs of physical degradation

SEM Images

Before Battery Cycling After 388 Cycles

Eos’ Robust Current Collector

Round Trip Energy Efficiency One-Hour Discharge/Charge Cycles

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Discharge/charge cycles

Ro

un

d T

rip

En

ergy

Eff

icie

ncy

(%

)

Spikes represent weather-related power outages

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20

40

60

80

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0 500 1000 1500 2000 2500

Energy Efficiency

Coulombic Efficency

Eos Superior to Gas Peaking Plants

* Chart Notes: Levelized Cost of Energy included cap. fix, and var. costs. Gas peaking cost estimate from Lazard, 2009, midpoint of est. range. Assump: 150MW facility, Capital cost $1,125/MW, Heat rate 10.5 MMBtu/MWh, Cap. factor 10%, Facility Life 35 years, Construction time 25 months. Eos: 2MW plant, 25% cap. factor (6hrs of energy production), Round-trip efficiency of 75%, Cap. cost for entire system with Eos battery $1.7/watt, O&M costs: $20,000/year for a 2MW/12MWh operating costs, Facility Life 30 years.

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Eos utility scale energy storage systems can be cheaper than gas peaking plants when compared at realistic operating conditions

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500

1000

1500

2000

2500

3000

3500

4000

4500

Q4 2009

Q2 2010

Q4 2010

Q2 2011

Q3 2011

Q4 2011

Q1 2012

Eos Competitive Advantages

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Fraction of capital and operating cost

System-level energy density

Safety

vs. Li-ion Eos

Long and deep cycle life

Nu

mb

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f C

ycle

s d

emo

nst

rate

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Value Proposition: Grid and Load Centers

End User Benefits • Time of Use (TOU) Energy management (arbitrage)

• Demand charge reduction

• Electricity supply reliability improvement (backup)

• Electricity supply quality improvement

Grid/Utility Benefits • Electricity peak shifting (arbitrage)

• Supply of flexible, distributable capacity

• Ancillary services

✴ Load following

✴ Frequency regulation

✴Voltage support

• Transmission congestion relief / upgrade deferral

• Renewable energy integration support via supply firming and time shift

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A variety of overlapping revenue

streams

EOS EV Battery Metrics

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EOS excels with DOD, safety, cycle and calendar life

A dual EOS and power battery can add kW with small weight and affordable cost penalty

Eos EV Near-

term goal Eos EV Med-

term goal Average Li

Ion USABC Min

Goals USABC LT

Goals

System Level W/kg

91 145 2,445 150 200

System Level Wh/kg

120 180 135 460 600

System Level W/l

208 530 3,901 230 300

System Level Wh/l

273 620 228 150 100

Cost USD/kWhr

100 <100 300-1000 <150 100

19 EOS densities are system level including BOP

70kWh battery < $10,000 = EV with same range and cost as ICE vehicle

Expert Opinions of Eos

• SCE, Rittershausen J and McKonah, Moving Energy Storage from Concept to Reality, 2011.

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“Metal air batteries… have the potential to be lower-power, long-duration energy storage devices…” - SCE, 2011*

“ Eos has developed a number of improvements for the conventional zinc-air battery to become a viable secondary battery.”

- KEMA Energy Consultants

“(Eos’) novel non-flow design offers elegant approach to management of prior zinc-air issues.” - Electric Power

Research Institute

“Metal-air batteries contain high energy metals and literally breathe oxygen from the air, giving them the ability to store extreme amounts of energy.” - US Energy Secretary, Steven Chu

“I think that EOS is one of the most exciting and

promising early-stage ventures in the space,” -Steven Minnihan, Lux

Research

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MARKET/TECH 2011 2012 2013 2014 2015

Eos Aurora

Grid Storage

Convergent Energy & Power

Convergent: Pre-Dev.

R&D

Pilot tests

Manufacture Prototype Q1

Asset Deployment

Marketing and Sales

Scale Manuf.

Business Timeline

Site Prep

• Prototype manufacturing plant in Edison, NJ online in 2013

• Scale manufacturing in 2013 / 2014

• Convergent Energy & Power project development

Summary

• The Eos Aurora will be a safe, reliable, non-toxic, non-combustible, low cost zinc-air energy storage system for the electric grid that can be sold for $1000/kw and $160/kWh, rechargeable over 10,000 cycles (30 years)

• Superior value proposition to incumbent technology: gas-fired turbines for additional generation capacity and gasoline engines for transportation

• Scaling up battery prototypes (100 kWh units) in 2012 in preparation for manufacturing and delivery of MW scale systems to first customers in 2013/4

• One full cycle includes full charge, discharge and additional frequency regulation over the course of one full day.

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www.eosenergystorage.com

A number of good references Metal Air Batteries: Their Status and Potential- a Review Keith F. Blurton and Anthony F. Sammells Journal of Power Sources, 4(1979) 263-279

Metal/Air Batteries: The Zinc/Air Case O.Haas, F. Holzer, K. Muller and S. Muller Chapter 22 Handbook of Fuel Cells – Fundamentals, Technology and Applications, edited by Wolf Vielstich, Hubert A. Gasteiger, and Arnold Lamm 2003 John Wiley and Sons ISBN: 0-471-49926-9

A Review on Air Cathodes for Zinc–Air Fuel Cells Vladimir Neburchilov, Haijiang Wang, Jonathan J. Martin, and Wei Qu Journal of Power Sources 195 (2010) 1271-1291

Metal-Air Batteries with High Energy Density: Li-Air versus Zn-Air Jang-Soo Lee, Sun Tai Kim, Ruiguo Cao, Nam-Soon Choi, Meilin Liu, Kyu Tae Lee, and Jaephil Cho Adv. Energy Mater. 2011, 1, 34-50

Please find these documents and a collection of energy storage information

in the Eos library: http://www.eosenergystorage.com/energy-storage-library/registration