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. 4/6/2019

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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 4/6/2019

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 4/6/2019

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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 4/6/2019

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 4/6/2019