Battery Separator Multilayer Structure for Uniform Inorganic Coating
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Solution Overview
Problem
The existing lithium ion secondary battery separators with a porous resin layer have low stiffness, leading to surface irregularities and non-uniform metal layer deposition, which affects the charging-discharging properties and shortens the battery's lifetime due to unstable current flow.
Innovation Solution
A multilayer body for batteries is developed, comprising a porous base material laminated over an organic support with an inorganic material layer formed using a sputtering method, enhancing surface uniformity and adhesion, thereby improving the handling and conductivity of the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a porous resin layer is used as a separator, then the separator has flexibility and can be formed easily, but the surface becomes irregular and difficult to handle due to low stiffness
Solution Approach 1:
The patent applies composite materials by combining a porous resin layer with a porous metal layer to create a separator that maintains the flexibility and formability of the resin while gaining the stiffness and handleability of the metal layer. This composite structure resolves the contradiction between ease of manufacture and ease of operation.
2Ease of operation
If a porous metal layer is formed over the resin layer to improve handleability, then the separator becomes easier to handle, but the metal layer deposition becomes non-uniform due to surface irregularities
Solution Approach 1:
The patent applies local quality by creating a specific configuration where the porous metal layer is formed with controlled thickness and porosity distribution. The metal layer is designed to have different properties at different locations - providing stiffness for handleability while maintaining uniform deposition characteristics for manufacturing precision.
3Reliability
If the porous metal layer thickness is reduced to 1 μm or less to maintain charging-discharging properties, then conductivity is improved, but the surface irregularities of the resin layer cause non-uniform metal layer formation
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of the porous metal layer to 1 μm or less while controlling its porosity and forming it on a specifically designed porous resin layer. This allows maintaining high conductivity for charging-discharging properties while achieving uniform metal layer formation through precise parameter control.
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 improves the uniformity of the separator's surface, stabilizes current flow, and extends the battery's service life by maintaining the charging-discharging property and preventing surface irregularities and damage during handling.
Implementation Method 1
forming an inorganic material layer over a principal surface of the porous film on a side of the porous base material by a sputtering method
Data Source
AI summary
A multilayer body for a battery according to the present invention includes: a separator including a porous base material formed in a plate shape, and an inorganic material layer situated over either or both of opposite principal surfaces of the porous base material; and an organic support over which the separator is laminated.