Secondary Battery Current Collector Layout for Higher Energy Density
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Solution Overview
Problem
The existing design of secondary batteries is hindered by the space occupied by the current collector, which reduces energy density due to its placement between the pole tabs and the housing.
Innovation Solution
The current collector and pole tabs are positioned side by side, with the pole tab being narrower than the end faces, allowing the current collector to overlap with the pole tab, thereby reducing the space occupied and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current collector is disposed between the pole tabs and the housing, then the current collector can be fixedly connected with the end of the tab, but the current collector occupies space which makes the secondary battery larger and reduces energy density
Solution Approach 1:
The patent transitions the current collector from a planar arrangement (between pole tabs and housing) to a three-dimensional overlapping arrangement. The current collector extends along the axial direction and overlaps with the pole tab in the radial direction, utilizing spatial dimensionality to reduce footprint while maintaining connection integrity.
Solution Approach 2:
The current collector is positioned to overlap with the pole tab, with the current collector's main body at least partially located between the end face and the housing. This nested spatial arrangement allows the current collector to be accommodated within the existing structural envelope without requiring additional lateral space.
2Reliability
If the current collector is disposed between the pole tabs and the housing, then the current collector can be fixedly connected with the end of the tab, but the current collector occupies space which affects energy density
Solution Approach 1:
By arranging the current collector to overlap with the pole tab in the radial direction and extend along the axial direction, the design utilizes vertical stacking to reduce horizontal space occupation, thereby increasing the proportion of active materials and improving energy density.
Solution Approach 2:
The current collector and pole tab are merged in space through overlapping arrangement, where the current collector's main body is positioned to overlap with the pole tab. This spatial merging eliminates wasted space and allows more efficient utilization of the battery internal volume for energy-storing components.
3Volume of moving object
If the pole tab is narrower than the end faces, then the main body and pole tab can be disposed side by side, but the pole tab provides less structural support
Solution Approach 1:
The pole tab is designed with differentiated dimensions: narrower in the radial direction (second direction) to enable overlapping arrangement, but maintaining sufficient length in the axial direction (first direction) to provide adequate structural support and electrical connection. This local quality variation optimizes both space utilization and mechanical strength.
Solution Approach 2:
The combination of the narrower pole tab and the current collector's main body creates a composite structural system. The current collector provides additional mechanical support and electrical conductivity, compensating for the reduced cross-sectional area of the pole tab while enabling the space-efficient overlapping configuration.
Data Source
AI summary
The present application relates to a secondary battery and a battery module. The secondary battery comprises: a casing, which is provided with an accommodating hole with an opening; a top cover assembly, which is in sealed connection with the casing to close the opening; an electrode assembly, which is arranged in the accommodating hole, and comprises two end faces opposite to a first direction perpendicular to an axial direction of the accommodating hole, and tabs extending from the end faces, the electrode assembly comprises two or more electrode units, wherein two or more electrode units are stacked in the axial direction, and in a second direction perpendicular to the axial direction and the first direction, the size of the tabs is smaller than that of the end faces; and a current collector, which comprises a body portion.