Microbattery Through-Silicon Via Electrodes Hermetic Sealing
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Solution Overview
Problem
There is a challenge in creating a hermetic seal for small, low-profile batteries with charge capacity of 1 mAh or less, particularly for lithium-based batteries that cannot be exposed to moisture, as existing packaging options struggle to achieve a seal width of 100 μm or less.
Innovation Solution
The solution involves forming through-silicon vias in the anode and cathode structures with conductive liners and using a metal overcoat to seal the battery components, allowing for electrical access without risking short circuits, and employing a metal joint or adhesive for bonding, which can include materials like indium or low-melting-point solders for hermetic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small physical dimensions and low profile are used for microbatteries, then charge capacity can be reduced to 1 mAh or less, but it becomes difficult to achieve full hermetic sealing with seal widths of 100 μm or less
Solution Approach 1:
The patent transitions from planar sealing to three-dimensional sealing by forming vertical walls that extend upward from the battery components. These walls create a enclosed cavity structure where the sealant can flow and conform to multiple surfaces (side walls, top surface, and bottom surface), achieving hermetic sealing in a compact volume without requiring large seal widths.
Solution Approach 2:
The patent employs a sealant material that exhibits flexible, conformal flow characteristics to fill and seal the cavity formed by the vertical walls. This flexible sealing approach allows the sealant to adapt to the precise geometry of the microbattery components and walls, ensuring complete hermeticity even with minimal seal widths of 100 μm or less.
2Use of energy by moving object
If lithium-based battery chemistry is used, then high energy density is achieved, but the battery cannot be exposed to moisture requiring complete hermetic sealing
Solution Approach 1:
The patent segments the battery structure into distinct functional components (anode, cathode, electrolyte, and sealant) contained within a vertically-walled cavity. This segmentation allows each component to be optimized for its specific function while the enclosed cavity structure protects the moisture-sensitive lithium-based chemistry from environmental exposure.
Solution Approach 2:
The patent creates an inert, moisture-free environment by completely enclosing the lithium-based battery components within hermetically sealed vertical walls. This isolated cavity prevents any contact between the moisture-sensitive battery chemistry and external atmospheric moisture, enabling safe operation of high-energy-density lithium batteries.
3Reliability
If existing packaging options like metal can packages or flexible polymer packages are used, then batteries can be sealed, but seal widths must be several millimeters which is too wide for microbatteries
Solution Approach 1:
The patent moves sealing from a two-dimensional planar interface to a three-dimensional vertical cavity structure. By forming walls that extend upward from the battery components, the sealant can distribute its sealing function across multiple surfaces (side walls, top, and bottom), reducing the required horizontal seal width to 100 μm or less while maintaining complete hermeticity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively seals the battery components from moisture and air while providing electrical access, ensuring the integrity and functionality of the microbattery, even in small form factors.
Implementation Method 1
The conductive overcoat is formed over the anode structure and the cathode structure to seal a cavity formed by the anode structure and the cathode structure. At least one of the anode substrate and the cathode substrate is pierced by through vias that are in contact with the respective anode conductive liner or cathode conductive liner.
Implementation Method 2
The conductive overcoat is formed over the anode structure and the cathode structure to seal a cavity formed by the anode structure and the cathode structure.
Data Source
AI summary
Batteries include an anode structure, a cathode structure, and a conductive overcoat. The anode structure includes an anode substrate, an anode formed on the anode substrate, and an anode conductive liner that is in contact with the anode. The cathode structure includes a cathode substrate, a cathode formed on the cathode substrate, and a cathode conductive liner that is in contact with the cathode. The conductive overcoat is formed over the anode structure and the cathode structure to seal a cavity formed by the anode structure and the cathode structure. At least one of the anode substrate and the cathode substrate is pierced by through vias that are in contact with the respective anode conductive liner or cathode conductive liner.