Sealed Battery Lead Welding Point Placement for Low Internal Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sealed batteries face high internal resistance due to the positioning of welding points between the sealing body (lid) and lead, which increases electrical resistance and hampers output power performance.
Innovation Solution
Optimizing the placement of welding points on the lid and upper current collecting plate to minimize the length of the lead, with a ratio of L1/X1 between 1 to 2.1, and using a ring-shaped or double-walled lead structure to reduce internal resistance and enhance output power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the welding point of lead to the lid is positioned at the center (beneath the cap), then the structure is simple and easy to manufacture, but the internal resistance increases and output power performance deteriorates
Solution Approach 1:
The patent inverts the conventional welding point positioning from the center (beneath the cap) to the peripheral region (outside the cap periphery). This inversion relocates the welding point of lead to the lid to a position where the radial distance from the center is greater than the cap radius, thereby reducing internal resistance and improving output power performance while maintaining manufacturing simplicity through standardized welding procedures.
2Reliability
If the lead length L1 is minimized, then internal resistance decreases and output power improves, but the ratio L1/X1 becomes too small making welding difficult and reliability decreases
Solution Approach 1:
The patent establishes an optimal parameter range for the ratio L1/X1 between 1.0 and 2.1, where L1 is the lead length from welding point to current collecting plate and X1 is the radial distance from lid center to welding point. This parameter optimization ensures that the lead is sufficiently short to minimize internal resistance while maintaining adequate length for reliable welding operations, achieving output power densities of 1400 W/kg or more.
3Device complexity
If a conventional single-point welding structure is used, then the device complexity is low, but the electrical resistance is high and productivity is limited
Solution Approach 1:
The patent segments the lead structure into multiple functional zones: a welding zone at the peripheral region of the lid, a intermediate zone with optimized length L1, and a connection zone to the current collecting plate. This segmentation allows each zone to perform its function optimally, with the peripheral welding position reducing resistance and the controlled L1/X1 ratio ensuring both low internal resistance and manufacturing feasibility, achieving high output power density without excessive complexity.
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
The optimized placement and structure of welding points result in a sealed battery with reduced internal resistance, achieving output power densities of 1400 W/kg or more, comparable to specialized nickel metal-hydride batteries.
Implementation Method 1
a welding point of lead to the inner surface of lid, in a flat view, outside the periphery of cap
Implementation Method 2
the electric resistance of a current collecting plate and lead connecting between a power generating element and a sealing body is a particularly important factor which greatly affects the performance of the battery
Data Source
AI summary
A sealed battery includes a lid closing a container of a sealed battery, an upper current collecting plate, a lead connecting an upper surface to an inner surface of the lid. A welding point of the lead is outside a position corresponding to a periphery of the cap. The lead includes a cylindrical lateral wall part extending vertically, an annular frame portion extending substantially horizontally from a first end of the lateral wall part, and a plurality of supplementary leads that extends substantially horizontally from a second end part of the lateral wall part. The frame portion extends from the first end part in substantially a first direction along a radial direction of the cylindrical lateral wall part, whereas the plurality of supplementary leads extends from the second end part in substantially a second direction opposite to the first direction along the radial direction.