1. Development of Lithium Batteries for Powering Sensor Arrays
SFR Workshop
November 8, 1999
Nelson Chong, Brianna Fehlberg, Jimmy Lim, Jeff Sakamoto, Dr. Bruce Dunn Advisor, UCLA
Berkeley, CA
In this project we investigate the feasibility of integrating ultra-low profile, rechargeable batteries into silicon substrates, for autonomous sensor application.
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4. 4/6/2019

5. Comparison of Encapsulated and Packaged Battery
4.5 4
3.5 a b 3
0.05
0.1
0.15
0.2
0.25
0.3 1 2 3 4 5 6
Cycle
Capacity (mAh/cm )
Battery in Epoxy
Battery in Bag
Discharge at 1 mA/cm2
5cycles c
0.5 1
1.5 2
2.5
1000
2000
3000
4000
Voltage
5000
6000
7000
8000
9000 d
Time (seconds)
Encapsulated battery
comparable to packaged;
3cm x 3 cm cell to
provide > 2mAh capacity
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6. Encapsulated 3.5 volt Battery held for 10 minutes
under Vacuum and Temperature
10 minute 1
Condition
1 Atm
VAC
Heat at 80 o C
VAC and Heat 80 o C
0.9
Cycling
1 Atm at 25 o C
1 Atm at 25 o C
1 Atm at 25 o C
1 Atm at 25 o C
Condition
0.8 ) 2
0.7
0.6
0.5
Capacity (mAh/cm
0.4
0.3
0.2
0.1 1 2 3 4 5 6 7 8
Cycle
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8. Progress vs. Milestones
Year 1: Milestones accomplished
Packaged 7 Volt lithium battery mounted on wafer
Encapsulation scheme identified and under test
Year 2: Program in progress
• Encapsulated lithium battery integrated in wafer well
• Battery tested under appropriately aggressive conditions
- Vacuum
- Elevated temperature
- RF fields
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9. Plans for 2000 - 2002 Develop higher temperature capability (150°C)
Utilize higher temperature component materials
Construct battery directly on wafer
Integrate materials processing into battery fabrication
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