Pouch Battery Tab Sealing for Uniform Sealant Layer Thickness
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Solution Overview
Problem
The uneven distribution of the sealant layer in the tab part of pouch-type secondary batteries leads to insulation defects and reduced chemical resistance due to the polymer material being pushed from the sealed portion to the unsealed portion during sealing, resulting in thinner thickness and inadequate pressure and heat transfer.
Innovation Solution
A sealing apparatus with a first and second sealing block configuration that includes a third area with a heated atmosphere to ensure even distribution of the sealant layer, maintaining the thickness of the inner layer by adjusting the step between the sealing blocks to evenly transfer heat to the unsealed portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pouch type sheet is directly sealed on the lead tab film in the tab part, then the sealing process can be completed, but the polymer material of the sealant layer is pushed from the sealed portion to the unsealed portion, causing uneven thickness distribution and reliability issues
Solution Approach 1:
The patent applies local quality by creating a stepped structure on the sealing block where different regions have different heights. The first sealing block has a first region that contacts the pouch type sheet and a second region that does not contact it, forming a step. This localized structural variation ensures that polymer material in the unsealed portion receives adequate pressure and heat without being pushed outward, maintaining uniform thickness distribution while completing the sealing process.
2Reliability
If sealing blocks press and heat the sealed portion, then sealing is achieved, but the polymer material is pushed out to the unsealed portion where pressure and heat are only transferred to ambient conditions, preventing uniform melting and adhesion
Solution Approach 1:
The patent implements local quality through a stepped sealing block structure where the first sealing block has a first region at a higher level that contacts the pouch type sheet and a second region at a lower level that does not contact it. This creates localized pressure distribution where the unsealed portion receives controlled pressure and heat from the stepped structure, enabling uniform polymer melting and adhesion without material push-out, thus achieving both reliable sealing and uniform thickness distribution.
3Productivity
If the sealant layer thickness is reduced in the unsealed portion due to polymer push-out, then the sealing process completes, but insulation defects and poor chemical resistance occur, reducing long-term reliability
Solution Approach 1:
The patent applies local quality by designing a stepped sealing block where the first sealing block has a first region that contacts the pouch type sheet and a second region that forms a step and does not contact it. This localized structural modification ensures adequate pressure and heat transfer to the unsealed portion, preventing polymer material push-out and maintaining sufficient sealant layer thickness. Consequently, both sealing process completion and long-term reliability including insulation and chemical resistance are achieved.
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
Prevents insulation defects and enhances long-term reliability by ensuring the sealant layer is evenly formed across the sealed and unsealed portions, maintaining the thickness of the inner layer and improving chemical resistance.
Implementation Method 1
the sealed portion is pressed and heated by sealing blocks
Implementation Method 2
the sealant cannot be uniformly melted on the lead tab film
Implementation Method 3
a third area including an empty space is formed between the second area and the outer layer of the pouch film stack, and the third area has a heated atmosphere
Data Source
AI summary
Disclosed are an apparatus and a method for sealing a pouch type secondary battery. Insulation defects are prevented and a long-term reliability, such as a chemical resistance, is improved by evenly forming a polymer material pushed from a sealed portion in a tab part even in an unsealed portion to prevent a thickness of a sealant layer from being smaller when a pouch outer material and a lead tab film are sealed in accommodating a secondary battery by using a pouch outer material including a pouch film stack.