Stepped Hole Electrode Terminal for Secondary Battery Energy Density
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Solution Overview
Problem
Secondary batteries for electric vehicles face challenges in achieving higher energy density due to the electrode terminal's design, which occupies space within the battery case, resulting in low energy density and high costs.
Innovation Solution
The design includes a cap plate with a stepped hole electrode terminal made of different materials, a current collecting member with an extending portion that is laser-welded to the first metal layer, and a composite connection interface, allowing for a more efficient use of space and improved energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode terminal is mounted in the mounting hole with parts located on both outer and inner sides of the cap plate, then the electrode terminal is securely fixed to the cap plate, but the electrode terminal occupies space in the case, resulting in low energy density
Solution Approach 1:
The electrode terminal is redesigned to extend primarily in the radial direction outward from the cap plate, with the majority of its length positioned outside the case. This dimensional repositioning moves the terminal mass from the internal Z-axis space to the external radial space, eliminating the space occupation problem while maintaining fixation through the mounting hole structure
Solution Approach 2:
The electrode terminal is nested through the mounting hole structure, where the mounting hole provides a through-hole path for the terminal to pass through the cap plate. This nesting approach allows the terminal to be securely anchored through the cap plate while extending outward, optimizing space utilization within the case
2Reliability
If a part of the electrode terminal is located on the inner side of the cap plate, then the electrode terminal can be fixed to the cap plate, but the gap between the electrode assembly and cap plate becomes too large, causing low energy density
Solution Approach 1:
The electrode terminal configuration shifts from occupying internal vertical space to extending primarily in the external radial direction. By positioning the terminal's main body outside the case and using the mounting hole for anchoring, the design eliminates the excessive gap problem while maintaining secure fixation
Solution Approach 2:
The electrode terminal is extracted from the internal case space and repositioned to extend primarily outward from the cap plate. This extraction removes the terminal mass from the limited internal volume, allowing better space utilization for the electrode assembly and improving overall energy density
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 enhances energy density by optimizing the use of space within the battery case and improving the structural integrity and reliability of the battery, while reducing the risk of internal short circuits during welding.
Implementation Method 1
the extending portion is laser-welded to the first metal layer
Data Source
AI summary
The present disclosure relates to a secondary battery and a method of manufacturing the secondary battery. The secondary battery includes: a case; an electrode assembly, accommodated in the case and including a main body and a tab connected to the main body; a cap plate, coupled to the case; an electrode terminal, located on an outer side of the cap plate and including a first metal layer and a second metal layer disposed one on top of another; and a current collecting member, connected between the tab and the electrode terminal.