Analysis of Li-Ion Battery Joining Technologies*
Wayne Cai, Ph.D. Manufacturing Systems Research Laboratory General Motors Global R&D Center Warren, MI, USA [email protected]
International Battery Seminar and Exhibit March 21, 2017
* W. Cai, B. Kang, and S.J. Hu, (2017), Ultrasonic Welding of Lithium-Ion Batteries, ASME Press * W. Cai, (2016), Lithium-ion Battery Manufacturing for Electric Vehicles: A Contemporary Overview, in Advances in Battery Manufacturing, Service, and Management Systems (eds J. Li, S. Zhou and Y. Han), John Wiley & Sons, Inc., Hoboken, NJ, USA.
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CONCLUSIONS 5.
Module) - to - (Module Assembly Pack 3)
Cell) - to - (Cell Assembly Module 2)
Cell Manufacturing Cell 1)
LANDSCAPE
MANUFACTURING: THE INDUSTRIAL INDUSTRIAL THE MANUFACTURING: BATTERY 4.
Joining Mechanical 5)
bonding - Wire
Second level 4)
Laser Beam Welding Beam Laser 3)
Welding Resistance 2)
Ultrasonic Metal Welding Metal Ultrasonic 1)
BATTERIES BATTERIES FOR TECHNOLOGIES JOINING 3.
Battery Modules and Pack and Modules Battery 2)
ion Battery Cells Battery ion - Li of Formats 1)
BATTERY CELLS, MODULES AND PACKS PACKS AND MODULES CELLS, BATTERY ION - LI 2.
BATTERY BATTERY 1. ELECTRIC ELECTRIC VEHICLES Outline
W. Cai W. 3 Updated 3/30/2015 Updated
Second level 1. Battery Electrical Vehicle Landscape Landscape Vehicle Electrical Battery 1. 1. Battery Electrical Vehicles
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W. Cai W. 5 Source: Google images Google Source:
Second level Chevy Volt Chevy Hierarchy of Battery Pack Manufacturing
Joining Processes of Battery Pack
Cell Level Module Level Pack Level
Electrodes Case Module-to- Cell-to-Cell -to-Tab (Sealing) Module
6 W. Cai 6 2. LI-ION BATTERY CELLS, MODULES & PACKS
Cylindrical Cells
(1) The cylindrical cells are known to be less volumetric efficient than prismatic cells, but were the first format of li-ion cells
(2) 18650 cylindrical cells are used in Tesla’s electric vehicles
(3) PTC, or Positive Temperature Coefficient, is a type of material that demonstrates significantly high electrical resistivity at high temperatures so as to melt the PTC itself to break the circuit at higher electrical current.
(4) CID, or Current Interrupt Device, is another passive device that breaks when the pressure inside a cell reaches high levels. Normally, when the cell is overheated, such as in a thermal-away, the pressure increases to a level to break the CID and thereof the circuit. W. Cai 7 2. LI-ION BATTERY CELLS, MODULES & PACKS
Prismatic Cells
W. Cai 8 2. LI-ION BATTERY CELLS, MODULES & PACKS
Pouch Cells
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highly dissimilar conductive materials materials
thin, multi-layer 100% reliability materials
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Ultrasonic Welding
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Ultrasonic Welding
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Ultrasonic Welding
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The Ultrasonic Bonding Mechanisms
A combination of the following four mechanisms may attribute to the bonding: (a) micro-melting (e.g., a few microns of thin interface layer melting), (b) metal interlocking (due to plastic deformation, particularly the severe deformation caused by sonotrode knurls), (c) atomic diffusion, and (d) metallic bonding W. Cai 14 Chevy Volt Ultrasonic Welding: between battery tabs and the interconnect bus bar
B.S. Kang, W. Cai, and C.A. Tan, “Dynamic Stress Analysis of Battery Tabs under Ultrasonic Welding,” ASME Journal of Manufacturing Science & Engineering, 136(4), 041011 (May 21, 2014).
http://insideevs.com/2013-chevy-volt-battery- W. Cai pack-and-drivetrain-disassembly-video/ 15 3. JOINING TECHNOLOGIES FOR BATTERIES
Ultrasonic Welding Quality Prediction #1: Temperatures and Bonding Quality
The finding: preheating enhances the bonding quality
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Ultrasonic Welding Quality Prediction #2: Fracture
Simulated deformation as compared with the experimental results
Fractures of the top layers should be avoided
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Ultrasonic Welding Quality Prediction #3: Vibration
existing welds Anvil Sonotrode
Interconnect Active welds (Cu)
Tab 1 Tab 3 GM Confidential Tab 4 Tab 6 (Al) (Cu) Tab 2 Tab 5
Cautions should be exercised to void damage from vibrations
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Resistance Spot Welding
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Laser Beam Welding
Laser Braze-Welding
W. Cai 20 BMW i3: Laser Welding
W. Cai 21 3. JOINING TECHNOLOGIES FOR BATTERIES
Wire-bonding
W. Cai 22 3. JOINING TECHNOLOGIES FOR BATTERIES
W. Cai 23 3. JOINING TECHNOLOGIES FOR BATTERIES
W. Cai 24 4. BATTERY MANUFACTURING: THE INDUSTRIAL LANDSCAPE Cell Manufacturing
W. Cai 25 4. BATTERY MANUFACTURING: THE INDUSTRIAL LANDSCAPE
List of battery cell components requiring joining
W. Cai 26 4. BATTERY MANUFACTURING: THE INDUSTRIAL LANDSCAPE
Welding occurs for the following four scenarios in a battery cell
W. Cai 27 4. BATTERY MANUFACTURING: THE INDUSTRIAL LANDSCAPE Module Assembly (Cell-to-Cell)
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Second level Conclusions Thank You!
W. Cai