Wound Battery Electrode Current Collector Welding
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Solution Overview
Problem
Current battery designs with wound electrode assemblies experience high electrical resistance between electrode plates and current collector portions due to the use of lead tabs for electrical connection, which hinders efficient energy transfer.
Innovation Solution
The battery design incorporates a cylindrical shaft core with a metal current collector portion that directly welds to the wound portions of the electrode plates, eliminating the need for lead tabs and reducing electrical resistance by creating a shorter, more efficient current collecting path, while also incorporating a safety vent system that effectively discharges gas to prevent pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead tabs are used to connect electrode plates to current collector portions, then the electrical connection structure is simple to manufacture, but electrical resistance between the electrode plate and current collector portion is high
Solution Approach 1:
The patent merges the lead tab connection function into the wound electrode assembly structure itself. The current collector portions are integrated with the wound electrode assembly, eliminating the need for separate lead tabs. This merging reduces electrical resistance by creating direct electrical contact between the electrode plates and current collector portions through the wound structure, while maintaining manufacturing simplicity through the integrated design.
Solution Approach 2:
The patent transitions from a two-dimensional planar connection (lead tabs connecting flat electrode plates) to a three-dimensional wound structure. The electrode plates are wound around a core in multiple layers, creating a spiral configuration where current collector portions are positioned at different radial and axial positions. This dimensional change allows direct electrical contact between electrodes and current collectors without requiring separate lead tabs, thereby reducing electrical resistance.
2Device complexity
If lead tabs are used for electrical connection, then the connection method is straightforward, but the number of components increases
Solution Approach 1:
The patent combines multiple functions into the wound electrode assembly structure. The current collector portions are integrated with the wound electrodes, serving both as structural support and electrical conduction paths. This eliminates the need for separate lead tab components, reducing the overall component count while maintaining straightforward electrical connection through the wound configuration.
Solution Approach 2:
The wound electrode assembly structure performs multiple functions simultaneously: it provides mechanical support, enables electrical conduction, and facilitates current collection. The current collector portions are multi-functional, serving as both structural elements of the wound assembly and electrical conductors, thereby eliminating the need for separate lead tab components and reducing overall device complexity.
3Productivity
If a through hole is provided in the protruding portion of the shaft core, then gas discharge efficiency is improved, but structural integrity of the shaft core is reduced
Solution Approach 1:
The patent applies local quality by providing the through hole only in the protruding portion of the shaft core, rather than throughout the entire shaft core structure. The protruding portion is specifically designed with the through hole to enable gas discharge from the distal end, while the main body of the shaft core maintains its structural integrity. This localized modification allows gas discharge functionality without compromising the overall strength of the shaft core.
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 design reduces electrical resistance and component count by eliminating lead wires and integrates a functional safety vent system that effectively manages internal pressure, enhancing the battery's performance and safety.
Implementation Method 1
the safety vent being capable of opening when internal pressure of the battery reaches a predetermined vent-opening pressure to discharge gas introduced into the bore of the shaft core inside the battery through the bore from the safety vent to the outside of the battery
Implementation Method 2
the protruding portion of the shaft core includes a through hole extending through the wall forming the protruding portion at a position further on the rear end side in the axial direction than the lid member, or, a cut-out formed by cutting off part of the wall forming the protruding portion from a distal end of itself to a position further on the rear end side in the axial direction than the lid member
Data Source
AI summary
A battery includes a cylindrical shaft core, and a wound electrode formed by winding a first electrode plate, a second electrode plate, and a separator around the outer periphery of the core. The wound electrode has a first wound portion formed by winding a first active material uncoated portion of the first electrode plate, a second wound portion formed by winding a second active material uncoated portion of the second electrode plate, and a power generating portion positioned between the first and second wound portions and formed by winding the first and second electrode plates, and the separator. The shaft core has a current collector portion composed of a metal, which is comprised of a joint portion connected to the first or second wound portion. The portions of the first or second wound portion, which are positioned on the outside of the shaft core in the radial direction with respect to the joint portion, are overlapped and welded to the joint portion.