Hot-melt Battery Pack Assembly via Segmented Injection Ports
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Solution Overview
Problem
Conventional battery pack manufacturing methods using hot-melt processes face high defect rates due to inadequate distribution of hot-melt resin and instability of protection circuit modules (PCMs) under external impacts, leading to increased costs and reduced durability.
Innovation Solution
The method involves arranging multiple injection ports in a mold to improve the mobility of hot-melt resin during the manufacturing process, allowing for low-pressure injection and stable mounting of the PCB to the battery cell without additional members, such as PCM cases or frames, thereby reducing defects and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional hot-melt process with limited injection ports is used, then the manufacturing process is simple, but the hot-melt resin is not distributed properly and the defect rate increases
Solution Approach 1:
The mold is divided into multiple sections with 8 or more injection ports distributed across upper, lower, and side parts, allowing hot-melt resin to be injected from multiple locations simultaneously. This segmentation of the injection system enables proper resin distribution throughout the mold cavity without requiring excessive pressure
Solution Approach 2:
Injection ports are strategically positioned at specific locations (upper part at electrode terminals, lower part, and side parts) to ensure localized and controlled resin flow. This local quality approach allows different regions of the mold to receive resin at optimal rates, preventing both under-filling and over-pressurization
2Manufacturing precision
If high pressure is applied to distribute hot-melt resin to distant mold portions, then resin distribution improves, but impact on the battery cell increases and defects occur
Solution Approach 1:
By dividing the injection system into multiple ports located at upper, lower, and side regions of the mold, the resin distribution task is segmented across multiple entry points. This eliminates the need for high-pressure single-point injection, as resin can flow naturally to distant portions from multiple closer locations
Solution Approach 2:
The hot-melt resin acts as an intermediary material that flows through the mold cavity from multiple injection ports. The resin's流动性 (fluidity) at elevated temperature allows it to reach distant mold portions without requiring excessive injection pressure, thereby protecting the battery cell from impact
3Reliability
If additional members such as PCM cases or frames are used to stabilize the PCB, then structural stability improves, but manufacturing cost increases and capacity decreases
Solution Approach 1:
The mold structure is merged with the battery cell assembly process, where the mold itself provides the stabilizing structure during hot-melt injection. The upper case, PCB, and battery cell are coupled together through the hot-melt process without requiring separate PCM cases or frames, achieving structural integration
Solution Approach 2:
The hot-melt resin serves multiple functions simultaneously: it acts as an adhesive to couple the upper case, PCB, and battery cell, provides structural support during assembly, and eliminates the need for separate stabilizing components. This multi-functionality reduces overall device complexity while maintaining reliability
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 reduces the defect rate, lowers manufacturing costs, and increases the capacity of battery packs by eliminating the need for additional components and ensuring stable assembly under external impacts.
Implementation Method 1
a hot-melt resin is injected into the mold 110 through injection ports 120 formed in the upper and lower parts of the mold in order to wrap the outer edge of the battery cell with the resin
Data Source
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AI summary
Disclosed herein is a method of manufacturing a battery pack including a battery cell having an electrode assembly received in a battery case, made of a laminate sheet including a resin layer and a metal layer, together with an electrolytic solution.