Battery Packing Bag Step Seal Around Electrode Lead Leakage
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Solution Overview
Problem
Secondary batteries face challenges in maintaining effective sealing performance due to issues with the packing bag's sealing mechanism, which can lead to electrolyte leakage and reduced energy density.
Innovation Solution
The design includes a sealing part with specific thickness and width ratios for the main body, step, and transition areas, along with an insulation part, to control the amount of colloids filled into the gap during hot pressing, ensuring a suitable range for sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the packing bag uses a simple sealing structure, then the manufacturing process is simple, but the sealing performance is insufficient leading to electrolyte leakage
Solution Approach 1:
The sealing part is divided into three distinct areas: main body area, first step area, and first transition area. Each area has specific thickness requirements (main body area thickness H1, first step area thickness H2 where H2 > H1, and transition area connecting them) to control colloid distribution and ensure reliable sealing while preventing electrolyte leakage
Solution Approach 2:
Different areas of the sealing part have different thicknesses to perform different functions. The main body area provides structural support, the first step area controls colloid flow, and the first transition area bridges them. The insulation part is positioned specifically to separate the sealing part from the electrode lead, ensuring local sealing quality where needed
2Reliability
If the sealing part thickness is increased to improve sealing, then the sealing performance improves, but the battery weight increases reducing energy density
Solution Approach 1:
Instead of uniformly increasing the thickness of the entire sealing part, the design segments it into areas with different thicknesses (H1 for main body, H2 for first step area where H2 > H1). This localized thickness increase provides necessary sealing performance only where required, minimizing overall weight addition
Solution Approach 2:
The sealing part has varying thickness distributed according to functional requirements. The main body area has thickness H1, while the first step area has greater thickness H2 specifically where sealing is most critical. This localized quality enhancement improves sealing performance without proportionally increasing overall battery weight
3Reliability
If the sealing part dimensions are optimized for sealing performance, then the sealing reliability improves, but the manufacturing precision requirements increase
Solution Approach 1:
The sealing part is segmented into distinct areas with clear thickness specifications (main body area H1, first step area H2, first transition area connecting them). This segmentation provides clear manufacturing targets for each area, making it easier to control dimensions and achieve reliable sealing through systematic quality control of individual segments
Solution Approach 2:
Each area of the sealing part has specific local quality requirements (thickness H1 for main body, H2 for first step area where H2 > H1, and width L1 for first step area). These localized specifications provide clear manufacturing guidance for each region, enabling precise control of sealing characteristics without requiring extreme precision across the entire component
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 configuration maintains the sealing performance within a suitable range, preventing electrolyte leakage and ensuring the battery's energy density is optimized.
Implementation Method 1
the connection layers of the two layers of the packing films are fused into a whole
Implementation Method 2
The insulation part is wrapped around outside of the electrode lead and separates the sealing part from the electrode lead
Data Source
AI summary
Provided is a secondary battery, including: an electrode assembly, a packing bag, an electrode lead and an insulation part; the electrode assembly is housed in the packing bag having a sealing part on edge, and the electrode lead is connected to the electrode assembly and passes through the sealing part. The sealing part includes a main body area, a first step area and a first transition area which are located on same side of the electrode lead along width direction, and the main body area, first transition area and first step area are successively arranged along direction approaching the electrode lead; the insulation part is wrapped around the electrode lead, and has a first portion which is located on a side of the electrode lead close to the main body area along width direction and covered by the first step area on both sides in thickness direction.