dr. nikita hall - cenex-lcv2018. nikita hall senior engineer ricardo uk ... © ricardo plc 2017...

Dr. Nikita HallSenior Engineer

Ricardo UK

Sponsors

© Ricardo plc 2017

Nikita Hall, John Bailey, Kevin Twell, Gary Bumfrey, Philip Griggs,

07 September 2017

evolutionary lectric ehicle atteryChallenges and Opportunities of Li-S technology

37 September 2017Cenex LCV 2017© Ricardo plc 2017

evolutionary lectric ehicle attery

• Ricardo Hybrid Group Overview and Introduction toREVB project•Mechanical Design and Development• Thermal Design and Development• BMS Hardware and Software Overview•Mini-Pack Build and Testing• Conclusion / Next Steps


Introduction

Ricardo’s - Global Reach

Over

2400employeesworldwide

CambridgeTechnical Centre

50

RicardoJapan

15

Ricardoin Korea

RicardoChina

100

RicardoGermany

240ChicagoTechnical Centre

50 Ricardoin Italy

RicardoPrague

170Detroit

Technical Centre

220

ShorehamTechnical Centre

530

RicardoAEA

400

RicardoIndia

20

Ricardo inMalaysia

Santa ClaraTechnical

Centre

MidlandsTechnical Centre

320

Ricardo inSaudiArabia

Ricardo inSouthAfrica

HES 10+ HES 120+ HES 58+ HES 40+

HES 228+

2700 staff in key global locations enable local delivery, backed by global centres of expertise, witha Hybrid and Electronic Systems design Specialists in excess of 228 heads Globally

CAE 95+CFD/thermal, FEA, performance simulation

Ricardo CATC Ricardo Prague Office

• Hybrid and electronic control module hardware and platform software expertise lead out of the Cambridgetechnical centre with support from our Prague office.

• Cambridge houses over 120 highly qualified engineers covering a variety of disciplines for hybrid systemsengineering and Prague over 50 further electronics engineers to support engineering programmes


Hybrid and Electronic Systems Engineering

Battery Pack &BMS

ArchitectureSelection eMachines Power

ElectronicsHybrid Control

Strategy

FunctionalSafety /

ISO26262

Independent consulting to OEMs and Tier 1 Suppliers on more than 200 projects to date, from pre-concept through development to production

Micro to FullHybrid Vehicles

Battery ElectricVehicles

Range ExtendedElectric Vehicles

FlywheelEnergyStorage

Fuel CellVehicles

Energy Storage& Grid Distribution

DemonstratorVehicle Builds

ChargingInfrastructure

Passenger Car -- Commercial Vehicles -- Motorsport -- Off Highway -- Agriculture -- Marine -- Defence -- Rail

INCORRECT_CMD_CLOOP_ACK_PCM

Q=0

Incorrect closed loopsteering correction

applied whenrequired in PCM

59

INCORRECT_TUG_TO_AC_ANG_BOEING

Incorrectdetermination oftug to A/C angle

(Boeing)

Page 11

INCORRECT_TUG_TO_AC_ANG_AIRBUS


(Airbus)

Page 10

INCORRECT_TUG_TO_AC_ANG

Incorrectdetermination of

need forcorrection

27

GATE221


correction towheel angles

58

INCORRECT_VEH_SPD

Vehicle speeddeterminedincorrectly

r=0Q=0

DATA_INCORRECT_CLOOP_ACK_GAIN

Static data related toclosed loop

ackermann correctiongain corrupted

r=0Q=0

INCORRECT_CMD_CLOOP_ACK_PCM

Q=0

Incorrect closed loopsteering correction

applied whenrequired in PCM

59

INCORRECT_TUG_TO_AC_ANG_BOEING


(Boeing)

Page 11

INCORRECT_TUG_TO_AC_ANG_AIRBUS


(Airbus)

Page 10

INCORRECT_TUG_TO_AC_ANG


need forcorrection

27

GATE221


correction towheel angles

58

INCORRECT_VEH_SPD

Vehicle speeddeterminedincorrectly

r=0Q=0

DATA_INCORRECT_CLOOP_ACK_GAIN

Static data related toclosed loop

ackermann correctiongain corrupted

r=0Q=0

Definition of highlevel requirements

Systemspecificationdesign & selection

Optimised systemsperformance

Topologysimulation andmodelling

Testing andvalidation definition

Cell type andchemistryselection

BMS design andengineering

Mechanical andthermal design

FMEA anddesignverification

Testing andvalidationfacilities

Topologyselection &system analysis

Electromagneticdesign & analysis


FMEA and designverification

Systemintegration,testing &validation

Benchmarking &troubleshooting

Hardware andsoftware design


FMEA and designverification

Systemintegration,testing &validation

Definition ofsystem &requirements

Control strategydevelopment

Rapid prototyping

MiL, HiL and SiLtesting

Integration andvalidation

Compliancesafety training

Hazard & RiskAssessment

FunctionalSafety Conceptdefinition

FunctionalSafetyManagement

FunctionalSafety Analysis /Audit

Definition of highlevelrequirements

Componentdesign &selection

System design &integration

Vehicle build andcommissioning

Testing andvalidation

ConnectedVehicles

AutonomousVehicles

VehicleSystemsControl

Introduction


Introduction

Project Requirements

Ricardo’s understanding of the requirement

Development ofreduced order modelsof batteries andmultivariableoptimisation methodsfor implementation ina real time controller

UK Cell technologyand manufacturerconducting R&Dwork to increase cellenergy density tobeyond 400Wh/kg(Lithium Sulfur)

Cell characterisation,testing and highfidelity modelling ofcells to extend cell life,energy usage andoperating boundaries.Identification of robustcontrol parameters

Chemistry, Cell and Model Development Implementation, Integration and Testing

BMS withcomputationalcapability to executemodel based controland optimisation.

Design & manufactureof A-Sample batterymodules with newOxis cells and newRicardo BMS.Develop thermalmanagement.

Test ,demonstrateand evaluateREVB technology.Load testing usingrepresentativepower profiles

Ricardo will provide the BMS, design and build the module, demonstrate, test and evaluatethe REVB technology


• No battery cell chemistry is suitable for all applications – selection is a trade-off between specificenergy and specific power requirements

Where does Li-S fit within the automotive industry?

050

100150200250300350400450500550600650700750800

0 2 4 6Specific Power - kW/kg

Solid state>2025

Ran

geSp

ecifi

c En

ergy

-Wh/

kg

Acceleration

Zinc

-Air

HEV

Li-Air

BEV/PHEV

NMCPower

LMOLFP

NCANMC

Energy

LTO

Al-Air

LTO

NMC 2020

48V

Li-S

Advantages

• Lightweight

• Safe

• Low Cost

Conclusion

Disadvantages

• Large

• Low Power Density


Mechanical Design Brief – Li-S Battery Pack

• How to hold the cell?– Cell must be self supporting

• The cells must be allowed to expand during use– No pressure applied to the cell body - detrimental to cell

performance• How to efficiently thermally manage the cells?

– Cooling of each individual cell when part of a module– Air cooling was the preferred method

• Simple, safe and low cost

• What is the end-use application?– Automotive

• Robustness and durability is key• Low cost, high volume production solutions

Mechanical Design and Development

Kevin Twell


Concept PhaseMechanical Design and Development


• The backing plate concept was developed– To reduce mass, the design allowed a cell to be bonded

either side

• The backing plate concept also allowed cooling channels to beincorporated between the two cells for consistent airflow.However this means that the cells would be cooled on one sideonly.

CHOSEN CONCEPT: Bonded Backing Plate

Consistent airflow gap – does notchange with cell expansion.

Cell expands this side only

Cells arranged in a module:

Cell body expansion can change the airflow



• Best Adhesive

• Best Substrate (backing plate) and surface treatment type• Important to obtain a bond strength sufficient to cope with the shock and vibration loads that

would be experienced in an automotive environment.

• Plasma treatment was chosen to increase the surface energy of the pouch material

Technical Challenge: Bonding and Surface Treatment

Damage clearly visible to pouch material

VACUUM PLASMA

Cell experiences 3 mbar during 60second treatment, causing the cell body

to bulge 4-5 mm each side.

CORONA PLASMA ATMOSPHERIC PLASMA

No detrimental effect to cells



• Computer Aided Engineering (CAE) simulation– The backing plate assembly was analysed structurally to assess its suitability for an automotive

environment.– Analysis showed that the design of the backing plates was able to withstand shock and

vibration loading for typical automotive use.

Structural rigidness – CAE simulationMechanical Design and Development


Structural mounting frame

Busbar supports Busbars

Fully Built Stack Assembly

Final Module Concept – 24s1pMechanical Design and Development


• Important to predict cell temperatures expected during real world driving

• Simulation is used to validate the module’s cooling performance before prototype is built

• CFD (Computational Fluid Dynamics) provides an insight to:– The air flow distribution within the module

• Does each cell receive similar cooling?• Temperatures in cells need to be similar for performance and ageing of cells

– Cell temperatures and heat taken away by the cooling• Can we provide sufficient cooling with an appropriately sized fan?

• Ricardo’s Vectis software was used to simulate air flow and cell temperatures simultaneously

Thermal Analysis - CFDThermal Design and Development

Philip Griggs


• CFD results of initial design (option 1) showed imbalance in cooling performance between cells

• The design was updated (option 2) which reduced the variation in flow rate to 3% (from 500%)

Thermal Analysis - Air Flow Distribution

0

100

200

300

400

500

600

1 2 3 4 5 6 7 8 9 10 11 12 13

Flow

rate

(L/m

in)

Channel number

Poor cooling in cell 1 for option 1

Thermal Design and Development


Real world:Single cell

Simulation:Single cell

Real world:Module

Simulation:Module

Cell temperatures – plan of attack

Input heat(unknown)

System Temperatures(known)

Input heat(unknown)

System Temperatures(unknown)

Input heat(determine)

System Temperatures(known)

Input heat(from #2)

System Temperatures(determine)

Matched

Matched

• CHT (Conjugate Heat Transfer) tells us about temperatures

• The chosen technology doesn’t follow I2R

1 2

34

Not I2R

Not I2R Want to find out

Thermal Design and Development


• The Battery Management System (BMS) is responsible for– Communicating with the Vehicle

• Pack needs to work as part of the vehicle– Energy available– Power limits– Diagnostic information

– Safety• High voltages can be lethal – protect the

user & system• Protect the cells & battery from damage• Impact on the vehicle of a loss/fluctuations

in available power– Reliability/life

• Ideally you need zero failures– Maximise life of pack / system

BMS Hardware and Software Overview

Why do you need more than just cells in a battery pack?

BMS – Control Module (BCM)

BMS – Acquisition Module (VTBM)

Gary Bumfrey


• Automotive packs are designed to matchthe pack operating voltage with systemcomponents

• Li-S chemistry based cells have nominalcell voltage approaching one half of theirLi-Ion counterparts– 400V pack requires approximately to

108 Li-Ion or 192 Li-S cells in series• Effects on the electrical

components– The manufacturers are rapidly

pushing for 600V packs and beyond


How does the switch from Li-Ion to Li-S affect the BMS?

• Effects on BMS1. 60 - 100% more cell voltage (& temp) measurement channels2. More compute power (more data and more complex algorithms)3. Increases hardware costs and physical space needed for electronics

11.1V (Li-Ion)

10.25V (Li-S)


• Ricardo built 14 new control modules

– Significantly increased processing power• supporting cell SOC and battery SOH prediction algorithms

– Improved cell data acquisition and conditioning

– Automotive application-ready tested hardware• Coated to survive automotive temp. & humid environments• Units passed basic electrical tests verifying functions work• Electrical robustness testing performed

– Tested operation at -40°C & +85°C– Tested for EMC – Radiated emissions & susceptibility– Tested for susceptibility to supply electrical transients


BMS – Control Module (BCM) Electrical Testing


VTBM Contactors BCM

Current sensor

24-Cell module


BMS integration - Pack Electrical system harnessing

Air Temperaturesensors

Acquisition Harness

Front Panelcomponents

Chosen components aretypical for an automotivegrade battery pack

High powercabling


Battery Specifications– Cells – 21 Ah Longlife Oxis cells– Configuration 24s1p– Pack Nominal Voltage – 49.2 V– Pack Capacity – 21 Ah– Target Energy Capacity – 1 kWh

Testing Procedure

• Charged at 0.1 C (CC) to 2.45 V / cell

• Discharged at 0.2 C (CC) to 1.5 V / cell

Results– Capacity - 20.76 Ah– Energy Capacity - 1 kWh– Energy Density – Cell weight - 5.592 kg

= 182 Wh/kg

Battery Build and Testing

Battery Testing Results - Energy Capacity



• Ricardo Hybrid Group Overview and Introduction toREVB project•Mechanical Design and Development• Thermal Design and Development• BMS Hardware and Software Overview•Module Build and Testing• Conclusion / Next Steps


Conclusions

• Designed, built and test 5 prototypeREVB batteries– 1 kWh Mini-Pack Battery– 4 x 0.5 kWh Mini-Pack Batteries

• Developed effective thermal modelsfor Li-S batteries

• Optimised Ricardo’s BMS hardwareand software– More powerful and accurate BMS

for Li-S technology


• No battery cell chemistry is suitable for all applications – selection is a trade-off between specificenergy and specific power requirements

Where does Li-S fit within the automotive industry?

050

100150200250300350400450500550600650700750800

0 2 4 6Specific Power - kW/kg

Solid state>2025

Ran

geSp

ecifi

c En

ergy

-Wh/

kg

Acceleration

Zinc

-Air

HEV

Li-Air

BEV/PHEV

NMCPower

LMOLFP

NCANMC

Energy

LTO

Al-Air

LTO

NMC 2020

48V

Li-S

Challenges

• Volume efficiency

• Power density

Conclusion



Thank you for your attention!John Bailey, Kevin Twell, Gary Bumfrey, Philip Griggs

dr. nikita hall - cenex-lcv2018. nikita hall senior engineer ricardo uk ... © ricardo plc 2017...

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