Secondary Battery Tab Sealant Moisture Barrier Design
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Solution Overview
Problem
The existing tab sealants in secondary batteries do not provide sufficient moisture barrier properties, leading to potential moisture infiltration and corrosion, and they struggle with ensuring adequate insulation and adhesiveness between metal terminals and packaging materials.
Innovation Solution
A secondary battery design featuring a resin film with specific heat of fusion characteristics, laminated with acid-modified polyolefin resins, and a structured packaging material configuration that includes heat-sealable resin layers and metal foil layers to enhance moisture barrier, insulation, and adhesiveness, ensuring effective sealing and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tab sealant is made of a heat-sealable resin to ensure adhesion to packaging material, then adhesion is improved, but moisture barrier properties are insufficient
Solution Approach 1:
The tab sealant is constructed as a composite material consisting of a polyolefin resin base combined with a moisture barrier agent (such as metal oxide, metal hydroxide, or layered silicate). This composite structure allows the sealant to simultaneously achieve adhesion through heat-sealing properties of polyolefin while gaining moisture barrier capabilities from the barrier agent, resolving the contradiction between adhesion and moisture protection.
Solution Approach 2:
The invention modifies the chemical composition parameters of the tab sealant by incorporating specific moisture barrier agents into the polyolefin resin matrix. This parameter change transforms the sealant from a simple adhesive material into a functional composite that provides both adhesion and moisture barrier properties, addressing the insufficiency of conventional heat-sealable resins.
2Manufacturing precision
If the thickness of tab sealant is reduced under heat sealing pressure, then better filling of lead end portion is achieved, but insulation between lead and packaging material is compromised
Solution Approach 1:
The tab sealant exhibits local quality differentiation where the moisture barrier agent distribution and resin composition are optimized for specific regions. The sealant maintains sufficient thickness at critical insulation locations while allowing controlled thinning at lead end portions during heat sealing, achieving both precise filling and reliable insulation through spatially varying material properties.
3Object-affected harmful factors
If polyethylene naphthalate film is used to improve moisture barrier properties, then moisture infiltration is reduced, but electrical insulation between lead and packaging material may be compromised
Solution Approach 1:
Instead of using polyethylene naphthalate film alone, the invention employs a composite tab sealant made of polyolefin resin combined with moisture barrier agents. This composite approach achieves moisture barrier performance comparable to or better than polyethylene naphthalate while maintaining electrical insulation properties, as the polyolefin base material provides excellent dielectric characteristics.
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 provides improved moisture barrier, insulation, and adhesiveness, preventing corrosion and leakage while maintaining electrical insulation, thus enhancing the overall performance and reliability of the secondary battery.
Implementation Method 1
a first packaging material and a second packaging material each of which includes a lamination of at least a metal foil layer and a heat-sealable resin layer made of a polyolefin resin
Implementation Method 2
Adhesion between a packaging material and a tab sealant can be ensured by the tab sealant being made of a heat-sealable resin
Implementation Method 3
the laminated packaging material is configured to include a metal foil layer to prevent infiltration of moisture into the secondary battery through the surface of the packaging material
Implementation Method 4
a tab sealant can ensure insulation between a lead and a packaging material
Implementation Method 5
Adhesion between a lead and a tab sealant can be improved by acid-modifying a polyolefin resin used for the tab sealant
Data Source
AI summary
A secondary battery of the present invention includes a battery element that includes a positive electrode and a negative electrode, a plurality of metal terminals that are connected to the positive electrode and the negative electrode, the metal terminals each having an outer peripheral surface provided with a resin film, and includes a lamination of at least a metal foil layer and a heat-sealable resin layer made of a polyolefin resin. A first package sealed portion, a second package sealed portion and a film sealed portion are each formed by pressing and heat sealing so as to have a thickness smaller than that of the peripheral region. The film sealed portion has a specific heat of fusion measured according to JIS K 7122 greater than that of a portion of the resin film other than the film sealed portion.