Wound Li-Ion Micro-Battery Layout Without Electrode Overhang
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Solution Overview
Problem
Current winding technology in cylindrical lithium-ion batteries faces challenges in producing micro-batteries with a height of less than 4 mm due to the overhang issue, which complicates electrode alignment and increases the risk of short circuits and Li metal deposition, making it difficult to manufacture rechargeable micro-batteries with smaller dimensions.
Innovation Solution
A novel cylindrical battery design featuring a wound jelly roll configuration with a Li metal film spaced apart from the anode, a membrane separator between the anode and cathode, and a single protruding tab, allowing for the production of micro-batteries with heights as low as 1.6 mm without the overhang issue, by ensuring proper alignment and preventing Li metal deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If current winding technology is used to reduce battery height below 4 mm, then micro-battery miniaturization is achieved, but overhang control becomes difficult leading to short circuits and Li metal deposition
Solution Approach 1:
The invention divides the electrode structure into distinct segments: a first electrode sheet, a second electrode sheet, and a third electrode sheet with different active materials. The separator is positioned between specific sheets (between first and second, and between second and third), creating clearly defined spatial relationships that eliminate overhang issues while maintaining proper alignment in miniaturized batteries.
2Volume of moving object
If overhang distance is reduced below 0.5 mm to achieve smaller battery dimensions, then battery size is reduced, but the risk of short circuits and Li metal deposition increases significantly
Solution Approach 1:
The invention introduces a separator as an intermediary component positioned between electrode sheets. The separator acts as a physical barrier that prevents direct contact between electrodes, eliminating the risk of short circuits even when electrode dimensions are reduced. This intermediary structure allows for compact battery design without compromising safety.
3Ease of manufacture
If traditional electrode arrangement is used in micro-batteries, then manufacturing process is simple, but Li metal deposition outside anode occurs causing capacity decay
Solution Approach 1:
The invention applies different active materials to different electrode sheets (first, second, and third sheets have different active materials). This local differentiation allows specific regions of the battery to perform specific functions, preventing Li metal deposition in critical areas while maintaining overall manufacturing simplicity through the consistent winding process.
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
The design enables the production of rechargeable micro-batteries with heights of 3 mm or less, maintaining efficient operation with high coulombic efficiency (>99%) and reduced internal stress, while avoiding the overhang-related risks of short circuits and Li metal deposition.
Implementation Method 1
When an electrolyte contacts the Li metal film and the anode electrode sheet concurrently, Li+ ions automatically ionized from the Li metal film will travel through the electrolyte
Implementation Method 2
a first membrane separator positioned between the anode and the cathode
Data Source
AI summary
A cylindrical battery having a wound jelly roll configuration that includes an anode current collector having a first surface and an opposing second surface; at least one anode disposed on the first surface of the anode current collector; at least one Li metal film disposed on the first surface anode current collector, wherein the at least one Li metal film is spaced apart from the anode; a cathode current collector having a first surface and an opposing second surface; at least one cathode disposed on the first surface of the cathode current collector; and a first membrane separator positioned between the anode and the cathode.