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LABAT’2017
June 13-16, 2017
How to Develop Best Graphite Products for Lead-Carbon Battery Applications
Dr. Joseph Li Dr. Francois Henry
Dr. Yujie Feng
Superior Graphite Co.
• Ownership- Family-owned & Partial ESOP • Since 1917- Providing carbon-based solutions • Employees- 260 globally • Turnover> $100M- >35% non-North American sales • Operations- 5 production sites; 2 R&D facilities • ISO 9001:2008 Certification- USA and Europe; ISO
14001:2004- Europe
Europe Headquarters, Sundsvall, Sweden Plants, Sundsvall, Sweden
World Headquarters, R&D, Chicago, Illinois Plants, Bedford Park, Illinois
Offices Höhr-Grenzhausen, Germany
Plant Russellville, Arkansas
Plants Hopkinsville, Kentucky
Office Shanghai, China
Locations
Classification of Carbon & Graphite
Unstructured Carbons Coke Carbon Black
Petroleum Coke
Pitch Coke Activated Carbon
Nanotubes
3D Structure ---Diamond
Graphene
Graphite
Macro-crystalline
Micro-crystalline Natural Flake
Vein
Synthetic Primary
Secondary
2D Structure
Applications of Graphite in Energy Storage Characterization of Graphite
Primary and Secondary Properties
• Performance additives in Advanced Lead-acid battery
• Anode Materials in Li-ion Battery • Conductive additives
• Alkaline battery, • Li-ion battery • Li-FeS2 battery • Li-MnO2 battery • Zn-Air battery • NiCd battery • Others
• Bipolar plate materials in Fuel Cells • Others
Typical Applications
Hexagonal structure with three dimensional
ordering.
High Purity Graphite Needed for Advanced Batteries
From J. Hu, etc. Int. J. Electrochem. Sci., 11 (2016) 1416-1433
Example: Graphite in advanced Lead acid battery applications: Graphite with high impurities show significant higher gassing
Carbons in negative plates
Carbon contents
Fe Cu Sb Mn Co Ni Expanded Graphite#1 1.50% 2370 56 ★ 53 ★ 23Expanded Graphite#2 1.50% 340 29 ★ ★ ★ ★ Expanded Graphite#3 1.50% 21 ★ ★ 28 ★ ★ Note: ★: metal impurity content <10 ppm.
Metal impurity contents / ppm
Purification Technologies
• Chemical Purification Technologies (e.g., acid leaching technology): Remove impurities including metallic elements with high concentration of either of acids
(HCl/HF/H2SO4) or alkaline salts Simplest form of purification and Economical Potential chemical residues in graphite Environmental concerns
• Thermal Purification Technologies:
Remove impurities including sulfur and metallic elements; Decomposition and carbothermic reduction of impurities/metal oxide. Impurity vapor diffuse outward between the cleavage planes of carbon and carried out by
fluidized bed furnace flue gas.
Thermal Purification Technologies
Acheson Process Horizontal process Moderately efficient High-purity Environmentally not unproblematic
Conductive Graphite Core
Coke Graphite SiC + SiO2 + C SiC
SiO2 + C SiO2 + SiC + C
Removable Side Wall
Superior Graphite EFB Technology
Vertical process flow High throughput High-purity Environmentally friendly
• Continuous processing capability • Consistent quality • Precise control of the process • Ultra-high Purity - +99.95% C • Improved conductivity • Economic effectiveness • Purify a wide range of carbons; Natural and synthetic graphite Carbon black Coke variants
SG Electro-thermal Fluidized Bed (EFB) Technology
Thermal Purification at Superior Graphite
Flake graphite extracted from ores and further upgraded to 95+% carbon
Thermally Purified flake upgraded to 99.9+ % carbon
Thermal
Purification
CeylonCanada
ChinaMozambique
Fe Content After Purification
Fe content before purification
5000
3300
450
3756.3
1619
10
0
1000
2000
3000
4000
5000
Fe C
onte
nt, p
pm
Source of the Natural Crystalline Graphite
Fe Content After Purification Fe content before purification
Effects of EFB Purification Process
market available products
Elements SymbolRaw
material (ppm)
EFB Purified (ppm)
Chemical Purified
599.95 (ppm)Aluminum Al 1570.3 5.6 7.0Arsenic As 4.5 <1.0 <1.0
Chromium Cr 0.7 <1.0 <1.0Cobalt Co 0.7 <1.0 <1.0Copper Cu 13.9 <1.0 <1.0
Iron Fe 2444.9 26.5 115.0Lead Pb 1.7 <1.0 <1.0
Molybdenum Mo 24.9 2.2 <1.0Nickel Ni 1.9 1.5 <1.0
Vanadium V 1.4 1.2 <1.04064.9 37.0 122.0Total
Applications in Lead-carbon Batteries
• Significant Cycle Life Improvement; • Improving dynamic charge acceptance; • Slow down internal resistance increase;
+ -
PbO2 Pb
Traditional Lead-acid Battery
Lead-Carbon Battery for Start-Stop Technology
+
PbO2
Pb with graphite /carbon
-
Carbon/Graphite
Carbon/Graphite Properties and Effect on Battery Performance.
• Electrical conductivity It is one of the most important carbon characteristics. Carbon conductivity is the parameter that allow it to work as conductive bridge among the numerous lead sulphate crystals that develop during battery operation at partial state of charge like in HEV use. Influence of conductivity is clearly seen on high rate discharges at low temperature in which it counteract the deleterious effect of distortion of lead structure caused by carbon addition. Other aspect with high influence of carbon conductivity, is the performance on cycle life. When adding high conductive graphite like expanded graphite or conductive carbons, a noticeable and consistent increase of cycle life is obtained.
• Specific Surface Area This is a carbon parameter directly related with battery charge acceptance. Charge acceptance have an almost direct relation with the SSA of the carbon added. The positive effect of carbon SSA, is also seen on cycle life. As a consequence of increased charge acceptance, the battery is capable of accepting charge in a more efficient way markedly improving the performance on cycle life, but could cause potential high gassing.
• Particle size It is directly related with the degree of distortion of the lead structure. The lower the particle size, the lower the distortion. Its effect has been tested on project 1012M in which working with pre-dispersed graphite, very high durations on High Rate Low temperature were obtain.
21-Jun-17/MTW 14
•Milling and Processing of high Purity Flake Graphite With a Variety of Processing Systems •Dry Blending of Graphite with Non-conductivity Material at Various Concentrations •Determination of Resistivity under Constant Load by Means of Two Point Method
High Purity Flake Graphite >99.9%C, Lc>300 nm
Hammer Milling Air classic Milling Fluidized Bed Milling Exfoliation /Air milling Super Exfoliation /Air milling
Blending With Non-conductivity Material MnO2
Measurement of Electrical Resistivity
Effects of Processing Technologies on Graphite Properties Concept of Investigation
Mill and Processing Technologies (Cont.) Fluidized Bed Milling
Sample 3
Exfoliation/Expansion Air Milling
Sample 4
Physical Properties in Summary
Product Type of Milling Particle Size d50 (micron)
Bulk Density (g/ccm)
SSA BET (m2/g)
Sample 1 Hammer Milling ~ 10 0.16 ~ 9Sample 2 Air Classic Milling ~ 10 0.09 ~ 7Sample 3 Fluidized Bed Milling ~ 10 0.06 ~ 9Sample 4 Exfoliation/Air Milling ~10 0.05 ~ 20Sample 5 Super Exfoliation/Air Milling ~10 0.045 ~ 23
Commercial Available Products
SG Product Portfolio – for Lead-acid Batteries FormulaBT® for
Lead-acid Batteries Negative Active Materials Additives
FormulaBT® ABG1010 Expanded Natural Graphite
FormulaBT® ABG1025 Expanded Natural Graphite
FormulaBT® LBG8004 Purified Natural Graphite
FormulaBT® 2939APH Purified Flake Graphite
FormulaBT® ABG1045 Expanded Natural Graphite
FormulaBT® ABG1010
FormulaBT® LBG8004
FormulaBT® 2939APH
FormulaBT® ABG2010 Super ExpandedNatural Graphite
FormulaBT® ABG2010
Power Assist Cycle Life
From M. Fernández, J. Valenciano, F. Trinidad, N. Mu˜noz, Journal of Power Sources 195 (2010) 4458–4469, project funded by ALABC
Effects on Cycle life improvement by graphite type
EG - expanded graphite; SG - synthetic graphite FG – flake graphite; CCB – conductive carbon black
End of discharge voltage and electrical resistance
Discharge Power vs. SoC (6V 10Ah modules) ABG1010 improved high rate low temperature discharge power
From Exide research group at Spain (Melchior Fernandez), project funded by ALABC
1.5% ABG1010 1% CB1+1% ABG1010 1% CB2
Summary
• Graphite properties, e.g. purity, electric conductivity, specific surface area as well as particle size, have significantly effects on Lead-acid battery performance.
• Superior Graphite’s Electro-thermal Fluidized Bed (EFB) technology has been demonstrated to be the most capable and efficient route to purify carbon and graphite materials for advanced battery applications.
• Processing technologies have large effects on graphite properties.
• Expanded (exfoliated) graphite products, produced with SG’s EFB technology, show high purity, excellent electric conductivity and high specific surface area, and best suitable for Lead-carbon battery application.