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Steven Hickey Head of battery testing

Part 1 – Introducing RedFlow and ZBM

RedFlow Background

What is a ZBM?

Battery basics – contrast ZBM & Lead Acid

A Battery is a series of Cells

A Cell is a couple of Half Cells

Electrodes and Electrolyte

Flowing versus Static Electrolyte

Characteristics Comparison

The Challenge of Battery Manufacture for Distribution Network Storage (Reasons to Flow Battery Part 3)

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The Winter’s Shed 2004

Founders Chris & Alex Winter

Prototype ZB cell 2004

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Board

Chairman Peter Pursey, AM (Non-exec director Austin Engineering)

Non-exec Anne-Marie Birkill (General partner of OneVentures)

CEO Phil Hutchings (Ex BE Geothermal GmbH, Wilson HTM, BHP)

CTO Chris Winter (Ex Schlumberger)

RedFlow has approximately 100 staff

Manufacturing and supply 50

Product development 30

Sales, admin, support 20

Amongst our team, RedFlow staff have

25 engineering degrees

9 masters degrees

2 PhDs (engineering)

2 CAs

5 other degrees (finance, business)

RedFlow’s staff have prior work experience with:

GE, Tyco, HP, Norgren, Elpro, Invensys, Australian

Hardboards, Energex, Rockwell, Luk GmbH, Saab,

Larimart SpA, Vinidex, Boeing, Fisher & Paykel, THQ

Inc, Hi-Tech Tooling, Powercell, BHP, QGC and others

Management

Dr. Alex Winter Chief Engineer Ex Schlumberger

Richard Aird COO Ex Lend Lease

Paul Clarke CFO Ex EY, KPMG, VanGlobe

Bernie Reinke GM Sales Ex Tektronix Comms, HP & Agilent

Bruce Ebzery Utility Sales Ex Energex

John Davis US Sales Ex Deeya, VRB (located US)

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RedFlow Staff & Factory

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RedFlow Manufacturing

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What is a ZBM?

3x33 Cell Stacks

240 Vac 150 W (electrical) circulation

pumps & fan

HDPE Tanks 90 l, 2.5M ZnBr2 Supported Electrolyte

Electrolyte heat

exchanger

900 mm

900 mm

Mass 230 kg

x x A Battery Basics

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bat·ter·y [bat-uh-ree]–noun, plural -ter·ies.

1. any large group or series of related things: a battery of questions. 2. Military: two or more pieces of artillery used for combined action. 3. Psychology: a series of tests yielding a single total score, used for

measuring aptitude, intelligence, personality, etc. 4. Law: assault and battery; an unlawful attack upon another person by

beating or wounding, or by touching in an offensive manner. 5. any imposing group of persons or things acting or directed in unison:

a battery of experts. 6. Electricity: Also called galvanic battery, voltaic

battery; a combination of two or more cells electrically connected to work together to produce electric energy.

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Zn++

Br-

Br Br

Zinc Collector e- e-

Zn

Separator

Bromine Collector

Br-

e- e-

ZBM Electrochemistry When charging electrical potential overcomes chemical potential, a current flows by conversion of species at the electrodes. This stored potential is released during discharge with reverse current flow.

DC Ch

Bromide ions in solution exchange with Bromine complex on electrode

1.07 V

0.76 V

Zinc ions in solution exchange with metal plate on electrode

Ch DC

DC

Ch

Ch

DC

Ions in solution migrate through porous separator to balance charge

+ -

+ -

Conventional current flow is opposite electron (e-) flow

Lead-Acid Electrochemistry

x x Flowing versus Static Electrolyte

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Lead Acid batteries don’t have pumps, why must the electrolyte flow in a ZBM? ZBM: 90 litres electrolyte ~= 14 kg Zinc in solution At full charge plated ~= 10 kg Zinc metal = 71% utilisation @ 100% DoD (Losses increase as concentration falls) LA (Equal 240 Ah @ Nom 48 V): Total battery mass: 272 kg Electro-active mass: 69 kg = 25% utilisation @ 100% DoD 53 litre H2SO4 from 6 to 2 molar (Typically limit DoD to ~20% for cycle life)

x x Flowing versus Static Electrolyte

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The ZBM requires flowing electrolyte, the concentration and density changes during a cycle. The energy storage capacity is partly determined by the amount of ions in solution. Hence a larger volume (than the stack) is pumped around the two circuits (zinc side and bromine side).

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ZBM Specs

Power (working) 5 kW Capacity 10 kWhr (240 Ah) Voltage Range 60-50 V Gross DC Efficiency 75%

x x Characteristics Comparison – BATTERY LIFE

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LEAD ACID BATTERY 80% of all LA battery failure is related to sulphation build-up. This build up occurs when the sulphur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's lead plates. Equalizing or over-charging the battery is intended to remove the sulphation (PbSO4) from the battery's plates. ZINC BROMINE BATTERY Separator degradation reduced with new electrolyte formulation. Conductive plastic electrode degradation reduced with new electrode formulation.

x x Reasons to Flow Battery

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All plastic materials – low cost , volume automation, recyclable 100% capacity utilisation – cf Lead-Acid 20-30% Electrodes not consumed in operation – long life Electrolyte unaffected by cycling – long life

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Steven Hickey Head of battery testing

Part 2 – how we design with ZBM

Hybrid ZBM/Lead Acid Design

AEST Project

ESV Project

GUSS Project

AusGrid Project

Scalability to MegaWatts

Communications, Data Logging and Control

The Challenge of Battery Manufacture for Distribution Network Storage (Reasons to Flow Battery Part 3)

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Lead Acid batteries have been developed for over 140 years. This is what most people and Engineers first think of when in need of energy storage (beyond hand-held devices). So it is understandable that all existing systems are intended for use with LA batteries. If you wanna beat ‘em join ‘em!

LA batteries are best operated at 100% SoC and with few small reductions in SoC. ZBMs are best operated in cycles with brief increases in SoC quickly returning to fully discharged. Combining the two characteristics in a hybrid system can achieve a better outcome.

Hybrid ZBM/Lead Acid Design

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AEST Project Advanced Electricity Storage Technologies

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5kW SMA SB 300 Ah LA

Grid BOS 300

Reference Design

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You can’t just connect two different batteries together … without managing the consequences! Strategies:

Divert excess current – SMA Grid-feed Vary LA voltage – 57/54, Tempcontrol Regulate ZBM output – MPPT, DC/DC converter

Hybrid ZBM/Lead Acid Design

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5kW SMA SB 300 Ah LA

+ 2 x 240 Ah ZBM

Power BOS Hybrid

Hybrid Design

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Hybrid Overflow Gridfeed

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Connecting ZBM to LA

ZBM Notes

Cells 34

Eo V 1.83 150 Ah Charge

Voc V 62.22

Ri ohms 0.15 Old battery

LA

Cells 24

Eo V 2.25

Voc V 54 Float

Ri ohms 0.0144

Vdiff V 8.22

Ih A 50 Grid Feed

Discharge I & P follow ZBM Nernst LA Vfloat

ZBM Icharge = 150 Ahr

ZBM Vcharge ZBM Voc

ZBM SoC ZBM Idischarge

Pgf

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ESV Project Energy Safe Victoria Bush fire risk minimisation trial

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Power+BOS

FM80 MPPT

4.8kW Solar Panels

YANMAR 7kVA

Diesel Generator

ESV System Arrangement

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Intermediate bus to match ZBM voltage

Tidal flow allows ZBM to dynamically balance PV and load

PV supply varies with Sol

AC load varies with demand

ESV Hybrid Design – MPPT

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ESV Cycles Chart

ZBM SoC

ZBM Solar Charge

LA SoC

Domestic Load

LA Volts MPPT Reg ZBM Volts

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ESV Energy Balance Report

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GUSS Project Grid Utility Storage System

• Connection: 3phase • Power/Energy: 15kW/60kWh • Grid Feed mode: Overflow • ZBM: 6 (ready for 12) • Inverters: 3 (3 used/6 cabled) • LA battery: Used, 42V nominal voltage, 106Ah

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GUSS Hybrid Design – MPPT

MPPT regulates ZBM discharge, LA not cycled

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AusGrid Project

Smart Grid, Smart City initiative 60 domestic installations Utility Demand Management System controlled

R510

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5kW SMA SB 240 Ah ZBM

Pure ZBM Design

RedFlow’s custom SMA firmware allows disabling BMS. The (33 cell) ZBM can now charge from the SMA. ZBM discharge is not compromised by LA hybrid.

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DC charge (Ah) -269.6 DC discharge (Ah) 225.6 ZBM Max SoC 100.0% DC charge (kWh) -16.8 DC discharge (kWh) 11.2

AC Charge energy (kWh) -18.0 AC Discharge energy (>=4.0kW, 2.11h) (kWh) 8.5 AC Discharge energy Total (kWh) 10.5

2h07m@4.0kW (Constant Power Feed)

Total Area 10.5 kWh

Total Area 18.0 kWh

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x x Scalability to MegaWatts

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M120:

• Connection: 3phase

• Power/Energy: 120kW/360kWh

• Grid Feed mode: Signal

• Batteries: 36

• Inverters: 24

• Connection type: Single phase AS4777 contactor

• LA battery: Not Used

• Phase balancing: Yes

• Power factor correction: Yes

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Work in progress: DC/DC converter – 4 quadrant, high efficiency DC pumps – variable speed reduced power

x x Communications, Data Logging and Control

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RedFlow

server

3G/Next G

Network

RTU

RTU

RTU

\\10.0.0.120

\\10.0.0.122

x x Communications, Data Logging and Control

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The RTU logs 4x32 point sessions uploaded to the Host.

Conventionally, related points share a session (e.g. SMA, ZBM).

Sample rate is adjustable from seconds to hours (typ 15 s).

Chart templates are customised for session, device and application.

Files are stored by CabinetID.

x x Communications, Data Logging and Control

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Live View represents the developing front for the human interface.

It now supports DHCP without port-forwarding.

A chart mode provides live observations of the remote systems.

User lists ease filtering of points

x x Questions?

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