OXIS Energy LtdLi-S Batteries for Energy Storage Applications

Dr David Ainsworth, Chief Technical Officer

Frontier Energy Storage Technologies and Global Energy Challenges 11th May 2016

OXIS Company Background

$70 million investment since 2005

Expanding rapidly: 3 fold increase in the number of employees since 2012 =>

59 today Highly trained staff (14 PhDs, 13 MSc/MA)

Cutting edge development facilities => second largest high specification dry room in Europe

Strong patent portfolio protecting IP => 79 patents granted, 81 pending, encompassing 25 families)

OXIS have been working on Li-S since 2005 at Culham Science Centre (Oxfordshire, UK)

High Gravimetric Energy• Theoretical 2500 Wh kg-1

• >400 Wh kg-1 achievable in the future

Low Predicted Costs

High Safety • Short Circuit Test • Nail Penetration Test• Overcharge• Thermal Stability

Producing Li-S battery cells at pilot scale Internally at OXIS and at manufacturing partners

OXIS Li-S Pouch Cell Technology

Variety of different sizes and capacities

2.0 – 3.4 Ah6 Ah – 10 Ah

> 20 Ah

10Ah Li-S pouch cells 3 KWh Li-S Rack Mounted Battery System

Introduction

Overview of Li-S cell technology

Key considerations for energy storage applications

OXIS materials research activities

OXIS activities relating to energy storage

Concluding remarks

Overview of Li-S Technology

Company Confidential

Li-S Batteries: Principles

Li

Curr

ent c

olle

ctor

Curr

ent c

olle

ctor

Li+

Li+

Li+

Li+

Li+

Li+

(-) (+)

Sepa

rato

r

+-

Discharge

Load / Charger

S8

(-) : 16 Li° → 16 Li+ + 16 e-

(+) : S8 + 16 e- → 8 S2-

16 Li° + S8 → 8 Li2S

Elemental sulfur

Conductive carbon

Binder Average voltage:

2.1 V (vs. 3.7 V of Li-ion)

Sulfur electrode specific capacity: 1675 mAh g-1 (vs. 170 mAh g-1 of LiFePO4)

Complex working mechanism: with intermediate species (soluble Li2Sx)

Theoretical gravimetric and volumetric energy: 2500 Wh kg-1 and 2800 Wh L-1, respectively

OXIS Key Technical Competences

R&D Pilot Production Battery SystemsMaterials Research Li-S Cell and Components Battery Design and Testing

History of OXIS Li-S Cell Development

Q2 2015: 10Ah CellEnergy Storage/LEV’s160Wh/kg

2010: 500 mAh pouch cell< 100 Wh/kg

Q4 2014:39Ah automotive cell220 Wh/kg

2011-2013: 1.7-3.4Ah pouch cells170 Wh/Kg

Q1 2015: Ultra light for UAV market35 Ah ; 300 Wh/kg

ULT

RA L

IGHT

LON

G LI

FE

Q3 2014: 25Ah automotive cells200 Wh/Kg

Q4 2014: Ultra light for UAV market6.5 Ah ; 265 Wh/kg

2013-2014: R&D prototype2 Ah ; 220-240 Wh/kg

Q2 2015: Ultra light for UAV market21 Ah ; 325 Wh/kg

Company Confidential

Improvements to Li-S Technology

OXIS is researching the following areas to improve cell performances

Sulfur/Carbons/Binders Current collectors Separators Lithium & protection mechanisms Electrolytes

Current CollectorSulfur/Carbon/Binder

ElectrolyteSeparator

LithiumCurrent Collector

Cathode

Anode

SeparatorSulfur/Carbon/Binder

Ni Tab

Al TabCathode

Anode

Separator

Pouch

20 R&D scientists (11 PhD’s) 20 production staff

Aiming to achieve 500Wh/Kg by 2020

Li-S Cells for Energy Storage Over 1400 cycles demonstrated on OXIS Long-Life Li-S cells

Key Considerations of Energy Storage

Considerations for Li-S Batteries in Energy Storage

Cost per KWh => > $200/KWh at over 3M units production

Cycle Life => 1400 cycles today, targeting 2000 cycles

Recyclability => No heavy/transition metals, lithium probable only material of value

Price per kWh of energy storage is key! => Strongly dependant of deployed location

Considerations for Li-S Batteries in Energy Storage

Other; 5%Separa-tor; 5%

Lithium; 15%

Cathode; 25%

Electrolyte 50%

A typical distribution ofmasses in an Li-S cell

Electrolyte can represent up to 50% of the weight of a cell!

Electrolyte and Lithium are most expensive cell components

Sulfur can only represent up to 15% of the mass of the cell

Materials Research Activities

Optimisation of Li-S cells from Materials Research

Cathode:New S/C composites

• Increase S8 loading• Increase S8 utilisation• Improve power capability

Electrolyte:Development of new additives and solvents• Maintain Safety• Increase S8 utilisation• Stability vs Anode

Anode:New anode coating

• Enhance cycle life• High resistance to corrosion• Reduce electrolyte degradation• Increase volumetric energy

Anodes for Li-S Batteries: Cycle Life

Coated Lithium Anode

Solution => Deposit thin protective coating onto anode surface

Required Properties:

Good adhesion to lithium metal

High sheer modulus

High ionic conductivity

Chemical resistance

Development of Protected Lithium Metal Anodes

Unprotected Lithium: 50 cycles Protected Lithium: 50 cycles

Very aggressive conditionsHigh surface area lithium

Integrity of foil is preserved

Cathode Development: Energy Density and Cost

TEM image of Sulfur/CNT composite material

Issues: Both Sulfur and Lithium are insulating Low surface capacity for good utilization Access/Wettability of active material Power Migration of Polysulfides

Solutions: Form 3D conductive network form S/CNT

composite Functionalization of binder/carbon materials? Control process parameters to tailor cathode

porosity/ morphology

Energy Storage Activities at OXIS Energy

OXIS Li-S Battery EvolutionBike Battery V2

using 3.4 Ah cells2013

Rack Mount Batteryusing 10 Ah cells

2016

Control BoardVery simple safety

circuitryComponents = 58

Bike Battery V1using 1.7 Ah cells

2012

Stackable Batteryusing 3.4 Ah cells

2015

Navyausing 3.4 Ah cells

2014

LINCAD BMSAdapted from LIPS10

RDVS BMSCell Control BoardBalancing and Safety

per cellComponents = 101

Control BoardPrototype only

Enhanced safetyCommunications

Components = 261

Control Board with integrated cell monitoring

ProductionSafety + reliability (fault

diagnostics)Components = 897

Cell Wiring BoardProduction orientated connectivity. Board per

module

Charger BoardFor direct PV connection

LIPS 10 Battery Development for MoD

Li-S Batteries for Stationary Energy Storage

3KWh Rack Mounted Battery

48KWh Battery System

1MWh Containerised Battery System

3 kWh Rack Mounted Battery• Prototype 1 of 3KWh Rack Mounted Battery manufactured in Q1 2016

– Prototype battery completed and initial tests successful

N.B. Flying leads are deliberate to allow testing of the prototype

3 kWh Rack Mount Battery SpecificationDimensions (h x w x d) 130 x 482 x 650 mmWeight 25 kgCell type OXIS POA0122 10Ah Long-Life Lithium-Sulfur cellsNumber of cells 144Environmental protection IP 20Storage temperature -27 to + 30 °COperating temperature 0 to 60 °C

Nominal voltage 50 V Minimum voltage 38 V Maximum voltage 56.4 V Rated stored energy 3 kWh Charge 0.1C, discharge 0.2CUsable stored energy 2.5 kWh Charge 0.1C, discharge 0.2CRated capacity 60 Ah Charge 0.1C, discharge 0.2COperating Depth of Discharge (DoD) 80 % Maximum continuous discharge current 60 A Peak discharge current (30 secs max) 180 A Maximum charging current 15 A Recommended charging current 6 A Equivalent series resistance < 100 mΩ Isolation to chassis 1 kV Cycle life 1400 cycles Charge 0.1C, discharge 0.2C, 80% DoD.Battery equivalent series resistance < 100 mΩ

Features:• Cell balancing• Cell safety monitoring circuits with redundancy• Electronic short circuit protection (LV only)• High voltage interlock/ trip (HV only)• Chassis isolation monitor• Isolated user CAN bus interface• Isolated user RS485 bus interface• Ethernet port• Internal history and fault logging

Master Controller

Battery System Architecture

System Integrator responsibility

OXIS custom design and manufacture

OXIS standard design, 3rd party manufacture

Key

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

Rack 1

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

Container

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

Rack 21

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

Rack 2

RMB

RMBRMBRMBRMBRMBRMB

RMB

SC

Inverter and grid connection

RMB Rack Mount Battery

SC String Controller

Conclusions Li-S Cells need to be low cost and long cycle life for Energy Storage

Costs of <$200/kWh are already possible at mass manufacturing scale

Cathode/Electrolyte Interface for reduced cost plus lithium protection for extended cycle life

Prototype Li-S battery systems for stationary energy storage are being tested by OXIS

OXIS R&D Development Partners

Joint Development Agreements

Development Programmes

Partnerships

Mark Wild Geraint MintonLaura O’Neill Rajlakshmi Purkayastha Steffen Schlueter Sylwia Walus

David Ainsworth Agata Swiatek Ashley Cooke Jacob Locke Justyna Kreis Lisset UrrutiaLukasz Kabacik

Martin CleggLukasz Solek Maciej SzczygielskiSebastien Desilani Sebastien Liatard Stephen Lawes Steve Rowlands

OXIS R&D TEAM

Acknowledgements