CFx/SVO Cathode Layering for Implantable Battery Energy Density
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Solution Overview
Problem
Existing battery designs for implantable medical devices face challenges in achieving high energy density and discharge rate capabilities while also providing an effective end-of-life indicator, with previous attempts at hybrid cathode materials like CFx/SVO suffering from low packing efficiency or reduced discharge rate.
Innovation Solution
A battery design featuring a cathode with a current collector bonded to alternating layers of sub-fluorinated carbon fluoride (CFx) and silver vanadium oxide (SVO), with the SVO filling bores through the CFx layer, enhancing energy density and discharge rate while providing an end-of-life indicator through a sloped discharge voltage curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-layer sandwiched design with two SVO outer layers and one CFx center layer is used, then the battery provides good EOL indicator and discharge rate capability, but the packing efficiency is low due to requiring two layers of current collector
Solution Approach 1:
The patent merges the CFx and SVO materials into a single integrated cathode layer rather than using separate layers with current collectors between them. This combines the high energy density function of CFx and the EOL indicator function of SVO into one unified structure, eliminating the need for multiple current collector layers and improving packing efficiency.
2Ease of manufacture
If CFx and SVO are physically blended together as one material, then the manufacturing is simplified, but the discharge rate capability is reduced compared to SVO-only cathode
Solution Approach 1:
The patent applies local quality by creating distinct regions within the cathode layer where CFx and SVO are positioned to perform their respective functions optimally. The SVO component is specifically positioned to provide discharge rate capability and EOL indication, while CFx provides energy density, maintaining the discharge performance of SVO-only cathodes while simplifying manufacturing.
3Use of energy by moving object
If CFx material is used to achieve higher energy density, then the energy density is improved, but the discharge rate capability becomes low and EOL indicator is lost
Solution Approach 1:
The patent uses composite materials by combining CFx and SVO in a single cathode layer. This composite structure allows the battery to achieve the high energy density from CFx while simultaneously maintaining the high discharge rate capability and EOL indicator functionality from SVO, resolving the trade-offs between these parameters.
Data Source
AI summary
A battery includes an anode, an electrolyte, and a cathode. The cathode includes a current collector having a first surface and a second surface opposite the first surface, a first material layer comprising sub-fluorinated carbon fluoride (CFx), and a second material layer comprising silver vanadium oxide (SVO) bonded to the first material layer. The first material layer comprising CFx may also be bonded to a third material layer comprising SVO, and the third material layer is bonded to the first surface of the current collector.