Metal-Housed Button Lithium-Ion Cell Sealing for Higher Energy Density
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Solution Overview
Problem
Lithium ion batteries with metal housings suffer from low energy density due to inefficient use of radial and axial space, and unreliable sealing, which can lead to short circuits and reduced yield.
Innovation Solution
A button-type lithium ion battery design featuring a metal housing with an insulating member between the metal housing and terminal, sealed through heat or adhesion, using non-metallic materials like polypropylene or epoxy resins, and a simplified three-layer structure that eliminates the need for a riveted structure, ensuring effective insulation and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer metal housing is configured as an anode with a riveted structure for insulation, then insulation between metal housing and aluminum cap is achieved, but the five-layer structure takes up too much axial space (thickness more than 1 mm), resulting in low energy density
Solution Approach 1:
The patent merges the insulation function and sealing function into a single integrated insulating member made of non-metallic material. This insulating member simultaneously provides electrical insulation between the metal housing and terminal, and sealing to prevent electrolyte leakage, eliminating the need for separate insulation layers and riveted structures. The merging of functions reduces the axial thickness from more than 1 mm to a much thinner structure, thereby improving energy density while maintaining insulation reliability.
Solution Approach 2:
The insulating member is designed with multi-functionality, serving as both an electrical insulator and a sealing element. By using non-metallic materials with both insulating and sealing properties, the single component performs multiple functions that previously required separate layers and structures, thus reducing overall thickness and improving space utilization in the axial direction.
2Reliability
If three-layer metal housing structure (inner housing, outer housing, sealing ring) is used, then sealing between inner housing and outer housing is achieved, but the structure takes up much radial space, resulting in low energy density
Solution Approach 1:
The patent extracts and eliminates the complex three-layer metal housing structure (inner housing, outer housing, sealing ring) and replaces it with a simplified single-layer metal housing. The sealing function is transferred to the insulating member made of non-metallic material that seals between the metal housing and terminal. This extraction of the sealing function from the metal housing structure itself allows for a much thinner radial profile, improving energy density while maintaining sealing reliability through the dedicated insulating member.
Solution Approach 2:
The patent changes the material parameter from metal to non-metallic material for the sealing component. By using insulating materials such as polypropylene, polyethylene, or epoxy resins for the insulating member, the structure achieves both electrical insulation and effective sealing with much reduced thickness compared to traditional metal housing structures, thereby improving radial space utilization and energy density.
3Reliability
If R-angle sealing technology with compressed plastic sealing ring is used, then sealing between inner housing and outer housing is achieved, but measurement of R-angle is not very accurate, resulting in low reliability and low yield
Solution Approach 1:
The patent replaces the mechanical R-angle sealing system with a chemical/adhesive bonding system. Instead of relying on precise mechanical R-angle measurements and compressed plastic sealing rings that require high manufacturing precision, the invention uses insulating members bonded through adhesion or heat sealing methods. This substitution eliminates the need for accurate R-angle measurement and control, significantly improving manufacturing precision and yield while maintaining sealing reliability.
Solution Approach 2:
The insulating member acts as an intermediary element that provides sealing between the metal housing and terminal without requiring precise geometric matching like R-angle sealing. The intermediary insulating member can accommodate manufacturing tolerances and provides reliable sealing through material properties (adhesion, heat sealing) rather than geometric precision, thereby improving both reliability and manufacturing yield.
4Productivity
If metal housing and terminal are directly connected, then electrical connection is achieved, but short circuit may occur between cathode and anode
Solution Approach 1:
The patent introduces an insulating member as an intermediary element between the metal housing and terminal. This intermediary non-metallic component provides electrical insulation to prevent short circuits between the cathode (metal housing) and anode (terminal), while still allowing for effective sealing and structural integrity. The insulating member mediates between the electrical connection requirement and short circuit prevention, ensuring both functions are achieved safely.
Solution Approach 2:
The insulating member copies the sealing and structural support functions of traditional direct metal connections while adding the critical insulation property. By using materials like polypropylene, polyethylene, or epoxy resins, the insulating member replicates the mechanical and sealing functions of direct metal connections but with the added benefit of electrical insulation, preventing short circuits while maintaining connection efficiency.
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 design enhances energy density by over 20% and improves manufacturing efficiency with a simpler structure and reduced parts, while ensuring reliable sealing and preventing short circuits.
Implementation Method 1
The metal housing and the terminal are sealed to the insulating member by means of heat or adhesion
Implementation Method 2
The metal housing and the terminal are sealed to the insulating member by means of heat or adhesion
Data Source
AI summary
The present disclosure provides a button-type lithium ion battery with a metal housing, including: a metal housing; a cell, received in the metal housing; a terminal, disposed on an outside of the metal housing; at least one first electrode tab, arranged on the cell and electrically connected to the metal housing; at least one second electrode tab, arranged on the cell and electrically connected to the terminal; and an insulating member disposed between the metal housing and the terminal; wherein the insulating member is insulating and sealing the metal housing and the terminal; a polarity of the at least one first electrode tab is opposite to that of the at least one second electrode tab; a polarity of the metal housing is opposite to that of the terminal; the metal housing and the terminal are sealed to the insulating member by means of heat or adhesion.