Pouch Battery Case Sealing With Conformal Edge Coating
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Solution Overview
Problem
The existing manufacturing methods for pouch-type secondary batteries expose metal layers during the cutting process, leading to reduced battery performance due to moisture and air exposure, and previous solutions increase battery volume or fail to form effective sealing.
Innovation Solution
A method involving the formation of a conformal coating layer on the side surface of the sealing portion between the upper and lower cases of the battery case, using a laminate sheet with outer and inner coating layers, to prevent metal layer exposure, combined with heat sealing and resin coating to enhance sealing and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the battery case is cut during manufacturing, then the battery case can be formed to receive the electrode assembly, but the metal layer is exposed to moisture and air causing battery deterioration
Solution Approach 1:
A conformal coating layer is formed on the side surface of the sealing portion before final assembly, proactively protecting the metal layer from exposure to moisture and air during subsequent manufacturing and operation steps
Solution Approach 2:
The conformal coating layer acts as an intermediary protective barrier between the metal layer and the external environment (moisture and air), preventing direct contact and subsequent deterioration
2Reliability
If an additional sealing portion is formed by pressing to prevent metal layer exposure, then metal layer protection is improved, but the inner resin layer must be formed thick increasing battery volume
Solution Approach 1:
The conformal coating layer is applied locally and conformally to the side surface of the sealing portion, providing targeted protection exactly where the metal layer is exposed without requiring thick coating throughout the entire battery structure
Solution Approach 2:
Instead of increasing thickness in the radial direction (which would increase volume), the solution applies a conformal coating that follows the surface geometry, providing protection through surface coverage rather than bulk thickness
3Reliability
If an additional sealing portion is formed by pressing, then sealing is attempted, but parts of the exposed metal layer surface fail to form effective sealing
Solution Approach 1:
The conformal coating layer serves as an intermediary that uniformly covers the metal layer surface, ensuring complete and consistent protection across the entire exposed area without the variability associated with pressing operations
Solution Approach 2:
The conformal coating process changes the protective parameter from mechanical pressing (which varies with pressure distribution) to a controlled coating application, achieving more uniform and predictable coverage
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 approach effectively prevents metal layer exposure, maintaining battery performance by blocking moisture and air, while maintaining a standard laminate sheet thickness and heat sealing conditions, thus reducing defects and increasing the battery's lifespan.
Implementation Method 1
forming an insulating coating layer including a conformal coating layer on the metal layer exposed to a cut surface
Implementation Method 2
heat sealing and resin coating to enhance sealing and protection
Data Source
AI summary
A pouch-type secondary battery and a method of manufacturing same are capable of completely protecting a metal layer from moisture or air by forming an insulating coating layer including a conformal coating layer on the metal layer exposed at a cut surface of a battery case. The method includes a first step of preparing a battery case including an upper case and a lower case by cutting a laminate sheet including an outer coating layer, a metal layer, and an inner coating layer; a second step of receiving an electrode assembly between the upper case and the lower case; a third step of forming a sealing portion by contacting outer peripheries of the upper case and the lower case; and a fourth step of forming a conformal coating layer on a side surface of the sealing portion so as to prevent exposure of the metal layer.