Battery Pack Resin Coating for Dimensional Accuracy and Weight Reduction
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Solution Overview
Problem
Lithium ion secondary battery packs face challenges in achieving high dimensional accuracy, mechanical strength, and lightweight design due to issues with film-shaped packing members, such as large dimensional tolerance and low bonding strength with resin, which increases thickness and weight, making them unsuitable for portable electronics.
Innovation Solution
A battery pack design featuring a frame member surrounding a packing member with a uniformly thick coating layer formed from a curable resin, applied without molds, using a spin coater to ensure high dimensional accuracy and mechanical strength while maintaining light weight and low cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metallic can is used for sealing the battery element, then high dimensional accuracy is ensured, but the battery pack becomes thicker and heavier
Solution Approach 1:
The patent changes the material parameter from metallic can to film-shaped packing member, and changes the sealing method from mechanical sealing to resin coating. This allows achieving the required sealing performance with a lighter, thinner film structure while maintaining dimensional accuracy through the resin coating process
Solution Approach 2:
The patent uses a composite structure combining film-shaped packing member (aluminum laminate film) with resin coating layer. The film provides the basic containment structure with low weight, while the resin coating provides the sealing and bonding function, creating a lightweight yet dimensionally accurate battery pack
2Weight of stationary object
If a film-shaped packing member is used instead of a metallic can, then the battery pack becomes thinner and lighter, but dimensional accuracy decreases due to large variations in battery element size
Solution Approach 1:
The resin coating acts as an intermediary layer between the film-shaped packing member and the battery element. It compensates for size variations of the battery element, providing a uniform outer dimension while allowing the flexible film to accommodate the varying battery element dimensions underneath
Solution Approach 2:
The patent changes the physical state of the packing structure from rigid (metallic can) to flexible (film-shaped member with resin coating). The resin coating can be applied in a controlled manner to achieve uniform thickness and dimensional accuracy despite variations in the underlying battery element size
3Strength
If the casing is made thick enough to protect the battery and circuit board from external shock, then mechanical strength is improved, but the thickness and weight of the battery pack increase
Solution Approach 1:
The patent uses a film-shaped packing member (aluminum laminate film) as a thin protective shell that provides adequate mechanical protection against external shock. The flexibility of the film allows it to absorb and distribute impact forces without requiring excessive thickness, thereby maintaining lightweight design while providing necessary protection
4Weight of stationary object
If a film-shaped packing member is used, then weight is reduced, but the strength of the packing member is inferior so injection pressure cannot be increased during molding
Solution Approach 1:
The patent creates a composite structure where the film-shaped packing member (providing lightweight containment) is combined with a resin coating layer (providing structural strength). The resin layer reinforces the weak film structure, enabling it to withstand injection pressures during molding while maintaining the overall lightweight characteristic of the film-based design
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 enables the formation of a high-strength, lightweight battery pack with improved energy density and manufacturing efficiency, allowing for smaller and more versatile battery designs suitable for portable electronics.
Implementation Method 1
a uniformly thick coating layer formed from a curable resin, applied without molds, using a spin coater
Implementation Method 2
coating layer formed of a curable resin on surfaces of the packing member
Data Source
AI summary
A battery pack has a battery obtained by packing a battery element with a packing member. The battery element is formed by winding or laminating an anode and a cathode through separators. The battery pack includes frame member surrounding the packing member packing the battery element and a coating layer constituted of a curable resin formed on surfaces of the packing member which are surrounded and demarcated by the frame member.