Lithium Secondary Battery Tab Bonding Layout for Lower Resistance
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Solution Overview
Problem
Existing lithium secondary battery technologies face issues with decreased output characteristics and productivity due to the need for complex folding and lamination processes that increase resistance and deteriorate mechanical bonding.
Innovation Solution
A lithium secondary battery design featuring a first and second laminate with insulating layers and conductive layers, a metal sheet aligned with end parts, and an electrode tab with distinct bonding marks to improve electrical connectivity and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple current collectors are folded and laminated to connect metal layers separated by insulating resin layers, then electrical conduction between electrodes and electrode tabs is achieved, but the structure becomes complex and resistance increases
Solution Approach 1:
The current collector is divided into multiple independent conductive layers, each sandwiching an insulating resin layer. This segmentation allows each layer to be independently connected to electrode tabs, simplifying the overall connection structure while maintaining reliable electrical conduction across multiple electrodes.
Solution Approach 2:
The patent transitions from a three-dimensional folded lamination structure to a planar stacked arrangement where multiple current collector-resin layer combinations are arranged in parallel. This dimensional simplification reduces structural complexity while achieving the same electrical connection function through a more straightforward manufacturing process.
2Reliability
If multiple current collectors are folded and laminated to connect metal layers, then electrical conduction is achieved, but output characteristics deteriorate due to increased resistance
Solution Approach 1:
By segmenting the current collection into multiple parallel conductive paths through separate current collector layers, the patent reduces the resistance of each individual path. This segmentation effect improves overall electrical conductivity and output characteristics while maintaining reliable connection between electrodes and tabs.
Solution Approach 2:
Multiple current collector layers are electrically merged through parallel connection to electrode tabs, creating a combined conductive system with lower equivalent resistance. This merging of multiple conduction paths enhances power output characteristics while achieving reliable electrical connection.
3Reliability
If complex folding and lamination processes are used to connect current collectors, then electrical conduction is achieved, but productivity decreases
Solution Approach 1:
The current collector system is segmented into standardized modular units, each consisting of a current collector layer with sandwiched insulating resin. These modular units can be independently manufactured and then easily assembled, significantly improving manufacturing efficiency while ensuring reliable electrical conduction.
Solution Approach 2:
The insulating resin layers are pre-positioned between current collector layers before final assembly, and electrode tabs are pre-connected to multiple current collector layers. This preliminary arrangement of components simplifies the manufacturing process and enhances productivity while maintaining reliable electrical connections.
Data Source
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AI summary
There is provided a technique for suppressing a decrease in output characteristics and productivity of a lithium secondary battery. A lithium secondary battery is provided. The lithium secondary battery includes (a) a first laminate including a first end part, (b) an intermediate laminate, (c) a second laminate including a second end part, (d) a metal sheet disposed to be lined up in the lamination direction with respect to the first end part and the second end part, the metal sheet having a first bonding mark due to bonding to any one of the first end part or the second end part, and (e) an electrode tab electrically connected to the first laminate and the second laminate. The electrode tab has a second bonding mark due to bonding of the first end part, the metal sheet, and the second end part. The second bonding mark is at a position different from a position of the first bonding mark in viewing from the lamination direction.