Afton Chemical presents Understanding Base Oils and Lubricants for Electric Drivetrain Applications

Understanding Base Oils and Lubricants for Electric Drivetrain Applications

Yungwan Kwak, Ph.D. May 20, 2019 STLE 74th Annual Meeting Nashville, Tennessee AftonChemical.com

Content Introduction New Fluid Requirements Thermal Properties of Base Oils

Electrical Property of Fluids Afton’s ETF Technology Summary

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eMobility - The Global Automotive Mega-Trend

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Drivers for Electrification

Grams CO2 per kilometer, normalized to NEDC

CO2 and EU6 regulations 270

US-LDV 250

(PC+LDT)

US baseline

230

China

219

China (2040) UK (2040) France (2040) India (2030) …

210 China baseline

EU

185

190

170 China 2015

167

150 EU baseline

130

US 2025

142

107

110

EU 2020

95

90 2000

2005

2010

2015

2020

Banning ICE Vehicles:

2025

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Development Focus will Shift Source: Afton estimate

Light Duty Vehicles on the road (M)

2000

1800

BEV

16%

Hybrid

16%

50% Growth in the Global Car Parc that require lubricants from 2015-2040

1600 1400 1200

Hybrid

1000

Traditional Internal Combustion Engine (ICE) Sales Peak by 2035

800

Traditional Traditional ICE ICE

600 400

68%

200 0 2000

2005

2010

2015

2020

2025

2030

Gradual changes of vehicle type and number Fluid decisions are being made now

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2035

2040

Traditional vs. New Drivetrains Ford F150

ICE

Traditional

Transmission

(‘powers the wheels’)

(includes stop-start & micro hybrid - eBoost)

Battery (‘powers the wheels’)

Parallel Hybrid (Mild & Full Hybrid)

ICE

Toyota Prius

Transmission (with e-motor) HYBRID / DHT

(‘powers the wheels’ & ‘powers the battery’)

BMW i3

Series Hybrid (PHEV & REEV)

Generator

Battery

(‘powers the battery’)

(‘powers the wheels’)

e-motor (Transmission) eAxle

Nissan Leaf

Full-Electric (BEV or Fuel Cell)

Battery (‘powers the wheels’)

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e-motor (Transmission) eAxle

Electric Drivetrain Fluid Requirements Cooling Ability  Thermal

conductivity, heat capacity

Electrical Properties  Electrical

conductivity breakdown voltage, dielectric constant conductivity,  Oxidative and thermal stability  Contamination

Material Compatibility  Engineering

plastics and wire coating materials  Cu protection

Performance at Higher Rotational Speed  Gear

and bearing protections  Foam and aeration

Overall Efficiency AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

Fluids Thermal Transfer (Cooling) Natural convection đ?‘¸ = đ?’‰đ?‘¨(đ?‘ťđ?&#x;? − đ?‘ťđ?&#x;?)

Forced convection

Q = Overall heat transfer (W) h = Heat transfer coefficient (W/(m2ďƒ—K)) A = Area (m2)

đ?‘´đ?’?đ?’–đ?’“đ?’?đ?’Žđ?’•đ?’”đ?’†đ?’‡đ?’‡ đ?‘ľđ?’–đ?’Žđ?’ƒđ?’†đ?’“ đ?‘´đ?’?

đ??†đ?’‚ đ??€đ?’ƒ đ?‘Şđ?’‘đ?’„ = đ?? đ?’…

ď ˛ = Density ď Ź = Thermal Conductivity Cp = Heat Capacity ď ­ = Kinematic viscosity

Natural convections

đ??†đ?’‚ đ??€đ?’ƒ đ?‘Şđ?’‘đ?’„

Forced convections

đ??†đ?’‚ đ??€đ?’ƒ đ?‘Şđ?’‘đ?’„ đ?? đ?’…

Higher Mo number higher cooling efficiency AftonChemical.com 2019Š Afton Chemical Corporation, All rights reserved

Thermal Property Measurement ASTM D7896 

Measurement of thermal property for engine coolants and related fluid

Thermal Conductivity () 

Ability of matter to transfer or conduct heat from a hot to a cold object  Lattice vibration (phonons) causes TC in non-metal

Specific Heat Capacity (Cp) 

Amount of heat energy required to raise the temp. of one kg of mass by 1 K

Thermal Diffusivity () 

Rate of transfer of heat of a material from the hot side to the cold side

Relationship  

=  x density x Cp Volumetric heat capacity (VHC) =  /  = Cp x density

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Transient Hot Wire TC Meter

Thermal Properties of PAOs PAO10 PAO 8 PAO 6 PAO 4 PAO 2

PAO10 PAO 8 PAO 6 PAO 4 PAO 2

Higher BOV PAOs provided both higher  and Cp  decreased as temperature increased Cp increased as temperature increased AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

Thermal Properties of Various BOs (Cooling) 300

2.80

at 100 oC 280

Ethylene glycol 2.60

260

Ethylene glycol Propylene glycol

240

2.40

Propylene glycol

220 200

B. O. Grp. 1 - 5

180 160

Cp (kJ/kgK)

 (mW/mK)

at 100 oC

B. O. Grp. 1 - 5 2.20

2.00 1.80

140 1.60

120 100

1.40

Selected data among 40+ BOs Understanding on base oils for cooling 

EG and PG have higher cooling efficiency but have EC concerns and are incompatible with current additive chemistry  Other base oils can be used where the fluid is in direct contact with hardware  About 30% performance difference range AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

No Influence of Add. TR on Thermal Property 160

2.20 11.4 (6X) 7.6 (4X) 3.8 (2X) 1.9 (1X) 7.6 (4X, AP)

150 145 140 135

2.10 2.05 2.00

130

1.95

125

1.90 0

20

40

60

80

100

11.4 (6X) 7.6 (4X) 3.8 (2X) 1.9 (1X) 7.6 (4X, AP)

2.15

Cp (kJ/kgK)

 (mW/mK)

155

120

Temp. (°C)

0

20

40

60

80

Temp. (°C)

Additive TR does not affect finished fluids thermal properties AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

100

120

Thermal Properties - Summary Thermal Properties (Cooling) Depend on BO Type and Viscosity  Additive

TR does not affect thermal properties

High  and Cp Important for Higher Performance  Higher

Mo provides higher cooling performance

About 30% Performance Differences Between Various BOs

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Electrical Conductivity/Resistivity ASTM D2624  Electrical

conductivity of aviation and distillate fuels  D4308 for electrical conductivity of liquid hydrocarbons by precision meter

Electrical Conductivity vs. Volume Resistivity unit: pS/m = 10-12 -1 m-1  Resistivity unit = 1/pS = 1012 m = 1014 cm Current leakage Electrical signal interference Short circuit

Electrostatic buildup

Emcee electronics Model 1152

Too Low

Too High

 Conductivity

Balance Between EC and Other Required Performances AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

EC of Fluids: Additive Effect 1.E+6

6

EC (pS/m)

1.E+5

T. R. 6X-A 4X-A 4X-B 2X-A 2X-B 1X-A

1.E+4

1.E+3

Rel. EC at 100 °C

5

T. R.

4

1X 2X

3

4X 6X

2 1 0

0

20

40

60

80 100 120 140 160

Temp. (oC)

Rel. Treat Rate (A)

Electrical conductivity is linearly proportional to additive TR Lower additive treat leads to lower EC AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

EC of Fluids: Viscosity Effect 14

10

12

9

50 oC °C

8

Rel. EC at 50 °C

75 oC °C

10

Rel. EC

20 oC °C

8 6 4

2 4.6

7

6.3

6

8.6

5

10.9

4 3 2

2

1

0

0 0

2

4

6

8

10

12

KV100 (cSt)

KV100 (cSt)

Electrical conductivity increases as viscosity decreases Balance required between lower viscosity for efficiency and EC AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

EC of Fluids: Viscosity and Temp. Effect

Similar additive chemistry led to similar EC within close viscosity ď ž

BO and commercial fluids have 3-5 orders of magnitude different

Lower viscosity increased EC noticeable AftonChemical.com 2019Š Afton Chemical Corporation, All rights reserved

EC of Fluids: Components Effect

Others (FM, AW, EP, CI, SS‌) Detergents Dispersants

ECs of various components are very different Understanding on majority of components for formulation Balance between EC and other performance AftonChemical.com 2019Š Afton Chemical Corporation, All rights reserved

Electrical Conductivity - Summary

Additives are the Main Influencer ď ž EC

linearly proportional to additive TR

Viscosity, BO Type, and Temperature Effect EC Significant EC variation from Various Components Balance Between EC and Other Performance

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ETF Technology Development 2.0E+5

170 ETF Benchmark

Benchmark

160

 (mW/mK)

1.6E+5

EC (pS/m)

ETF

1.2E+5

8.0E+4

4.0E+4

150

140

130

0.0E+0 0

20

40

60

80

100

Temp. (°C)

120

140

160

120 0

20

40

60

80

100

120

Temp. (°C)

Benchmark: industry well-known HEV fluid

New ETF has lower EC and higher  Components and BO selection are the key Need to maintain other traditional performance AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

ETF Technology Development

Composition (ppm)

Benchmark

ETF

P

282

69

S

632

1351

N

1890

695

74

27

FLS = 5 B

FLS = 8

100 °C (cSt) BV (40 °C, cP)

5.71 10,500

5.93 7,970

Flash point (°C)

175

213

D-130

1B

1B

FZG (A10/16.6R/120) FLS

5

8

4 ball EP (kgf)

200

200

Pin-on-vee block seizure load (N)

5000

7500

FLS = 5

FLS = 8

New ETF maintained min. conventional performances New ETF had superior performances AftonChemical.com 2019© Afton Chemical Corporation, All rights reserved

ETF Technology Development DKA test (170 °C / 192 h)

Nylon test (150 °C / 240 h)

Benchmark

ETF

SOT, KV100

5.82

5.79

+16

EOT, KV100

17.2

7.03

No crack

% KV100

191

21.4

Benchmark

ETF

% TS

+13

+17

% E

+10

Visual

No crack

Extended D-130 test (150 °C) ppm Cu by ICP

120

Benchmark

100 80 60 40

ETF

20 0 0

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40

80

120

160

200

Time (h) 2019© Afton Chemical Corporation, All rights reserved

Summary Insights Into Cooling Performance Provided Insights Into EC Property Discussed Prototype ETF Technology Developed  Had

high cooling performance and low EC

 Maintained

and further improved essential

performance features  Had

better Cu corrosion protection

 Balancing

all learnings enabled us to develop

advanced fluid technology  Afton

has know-hows to design better ETFs

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Thank you for your attention!

Any Questions?

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