Battery Terminal Insulation via Caulking and Composite Gasket
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Solution Overview
Problem
Rechargeable lithium-ion batteries face challenges in maintaining insulation and air-tightness, especially with larger external electrode terminals, which can lead to increased costs and risks of short circuits due to the softness of tetrafluoroetylene-perfluoroalkoxyetylenevinyl-ether copolymers (PFA) gaskets and terminal rotation.
Innovation Solution
A battery design that uses an insulating gasket with a higher melting point than the external and internal insulators, where the external terminal is fixed to the lid through caulking, ensuring insulation and air-tightness while using a harder external insulator to prevent short circuits, and reducing resin material usage for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external electrode terminal is enlarged to reduce resistance and suppress Joule heat, then the electrical performance is improved, but the gasket becomes larger and more expensive resin material is required
Solution Approach 1:
The patent uses a composite structure combining PFA gasket material with a fluororesin coating layer. The PFA provides base sealing properties while the additional fluororesin coating enhances the protective function and allows for reduced overall material usage while maintaining performance.
2Reliability
If PFA is used for the gasket material to maintain high air-tightness, then the sealing performance is improved, but the gasket becomes softer and more susceptible to destruction upon terminal rotation
Solution Approach 1:
The patent creates a composite structure by coating the PFA gasket with additional fluororesin. This composite approach maintains the excellent sealing properties of PFA while adding a harder protective layer that resists mechanical destruction from terminal rotation.
Solution Approach 2:
The patent applies different material properties to different parts of the sealing structure. The PFA base layer provides soft sealing contact for air-tightness, while the outer fluororesin coating provides harder mechanical protection, creating local quality differentiation within the sealing system.
3Reliability
If a harder external insulator is used to prevent short circuits from terminal rotation, then the safety is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces the need for complex mechanical reinforcement structures with a chemical/coating-based solution. By applying fluororesin coating to the insulator, the required hardness and protective properties are achieved through material selection rather than complex mechanical design, simplifying manufacturing.
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 solution effectively maintains air-tightness at high temperatures, reduces the risk of short circuits, and lowers material costs by using a smaller amount of expensive resin, enhancing the safety and reliability of the battery.
Implementation Method 1
an external electrode terminal is fixed to a lid by caulking so that the external terminal maintains an insulation property and a high air-tightness
Implementation Method 2
the insulating gasket is formed of a resin in which the melting point is higher than the external insulator and the internal insulator
Implementation Method 3
an external insulator arranged in an external surface of the lid and having a pedestal portion, an external terminal having a head portion arranged in the pedestal portion of the external insulator
Data Source
AI summary
In one embodiment, a battery includes an exterior can, an electrode group, a lid attached to an opening of the exterior can, and anode and cathode terminal portions arranged in the lid. At least one of the terminal portions includes an insulating gasket having a cylindrical portion, an external insulator having a pedestal portion, an external terminal including a head portion and the axial portion extended from the head portion, an electrode lead located in the exterior can and connected to the external terminal, and an internal insulator to isolate the lid and the electrode lead. The cylindrical portion of the external terminal is fixed to a through hole of the lid and an attachment hole of the electrode lead by a caulking. The insulating gasket is formed of a resin in which the melting point is higher than those of the internal insulator and the external insulator.