Development of near hermetic silicon/glass cavities for packaging of integrated lithium micro batteries
- 423 Downloads
A technology was developed for fabrication of very thin, chip-sized lithium secondary micro batteries. With help of wafer level processing the batteries can be directly integrated into silicon chips or MEMS devices. The batteries were packaged in 200 μm deep cavities of the silicon wafer and encapsulated with a glass substrate. Battery demonstrators were realized with 7 and 12 mm square and round foot prints. Near hermetic packaging was accomplished with the help of a UV curable epoxy seal that should ensure several years of battery lifetime. Bonding parameters, shear force and the water permeation rate of the adhesive were investigated. A capacity of 3 mAh/cm2 and an energy density of 10 mWh/cm2 were achieved. The electrical contact between the battery and the contact pads of the housing was investigated in detail. Electrical tests were made with encapsulated micro batteries and compared with macroscopic lithium polymer batteries. A reduction in capacity of approximately 10% was measured after 100 cycles.
KeywordsCurrent Collector Permeation Rate Water Permeation Battery Material Anisotropic Conducting Adhesive
Special thanks go to Konrad Holl, Martin Krebs, and Jürgen Lindner from Varta, Ellwangen, for the fruitful cooperation, supply of battery materials and electrode laminates. We also want to thank the HDI-WLP clean room team for processing Si and glass wafers. Thanks also to Peter Semionyk and Maria v. Suchodoletz for the shear tests.
- DE10 2007 012693 A1, “Micro battery and electrolyte dispensing system”Google Scholar
- Gozdz AS, Tarascon J-M, Gebizlioglu OS, Schmutz CN, Warren PC, Shokoohi FK (eds) (1995a) A new hybrid polymer electrolyte for lithium-ion rechargeable batteries. Proc Electrochem Soc no. 94–28Google Scholar
- Gozdz AS, Tarascon J-M, Schmutz CN, Warren PC, Gebizlioglu OS, Shokoohi FK (eds) (1995b) Polymer considerations in rechargeable Lithium ion plastic batteries. The Tenth Annual Battery Conference on advances and applicationsGoogle Scholar
- Hahn R, Marquardt K, Luger T, Reichl H (2005) Assembly of wafer level secondary batteries. International Symposium PowerMEMS TokioGoogle Scholar
- Mina HS et al (2008) Fabrication and properties of a carbon/polypyrrole three-dimensional microbattery. Journal of Power Sources 178:795–800Google Scholar
- Marquardt K, Hahn R, Luger T, Reichl H (2006) Assembly and hermetic encapsulation of wafer level secondary batteries. MEMS2006 Istanbul, pp 954–957Google Scholar
- Oukassi S et al (2006) Above IC micro power generators for RF-MEMS. DTIP of MEMS and MOEMS, Stresa, Italy, 26–28 April 2006Google Scholar
- WO2005036689 (A3), WO2005036689 (A2), EP1673834 (A3), EP1673834 (A0), DE10346310 (A1), Battery, especially a micro battery, and the production thereof using wafer-level technologyGoogle Scholar