Cylindrical Lithium Battery Tab Structure for Lower Heat Buildup
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Solution Overview
Problem
Conventional cylindrical lithium secondary batteries face issues with current concentration at electrode tabs leading to heat generation and safety risks, especially in large-capacity batteries, and the tap-less structure affects electrolyte impregnation properties.
Innovation Solution
A lithium secondary battery design with non-coated portions of the positive and negative electrode plates serving as electrode tabs, connected to a current collector with a large cross-sectional area, and optimizing electrolyte volume to 101% to 119% of the total pore volume, ensuring sufficient impregnation and reducing current concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional cylindrical battery with strip-shaped electrode tabs is used, then the battery structure is simple and easy to manufacture, but current is concentrated on the electrode tabs causing large resistance and heat generation
Solution Approach 1:
The electrode tab is divided into multiple segments (first electrode tab and second electrode tab) to distribute the current flow path. This segmentation reduces current concentration at any single point, thereby reducing resistance and heat generation while maintaining the conventional battery structure for ease of manufacture
Solution Approach 2:
The electrode tab structure transitions from a two-dimensional strip shape to a three-dimensional configuration with multiple tabs extending in different directions. This dimensional change increases the effective surface area for current collection and disperses heat generation across multiple contact points with the current collector
2Quantity of substance
If the battery size is increased to achieve high capacity, then the energy storage increases, but the heat and gas generated inside the battery increase causing temperature and pressure rise
Solution Approach 1:
The battery is divided into multiple independent pouch-type cells, each with its own sealing structure. This segmentation allows heat and gas to be contained and managed at the cell level rather than accumulating throughout the entire battery, reducing temperature and pressure risks while maintaining high overall capacity
Solution Approach 2:
The sealing body includes a relief structure designed to accommodate and relieve pressure before it becomes dangerous. This beforehand cushioning mechanism prevents catastrophic failure by providing a controlled pressure relief path, allowing the battery to safely handle the heat and gas generated during high-capacity operation
3Object-affected harmful factors
If a tap-less structure is applied to solve current concentration, then heat generation is reduced, but the electrolyte impregnation property decreases due to increased pressure inside the electrode assembly
Solution Approach 1:
The electrode plate has different structural qualities in different regions: the main body has active material coating for electrochemical function, while the tab region has no coating to serve as current collection. This local quality differentiation allows the battery to achieve low heat generation through the tab-less structure while the multi-pouch design compensates for electrolyte impregnation by providing pressure relief and maintaining proper electrolyte distribution
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 design reduces heat generation and improves thermal safety, enhances electrolyte impregnation, and achieves excellent output and lifespan characteristics, particularly in large-capacity batteries.
Implementation Method 1
the volume occupied by the electrolyte is 101% by volume or more and 119% or less based on the total pore volume of the positive electrode plate, the negative electrode plate, and the separator
Data Source
AI summary
A lithium secondary battery including: an electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction; a battery can accommodating the electrode assembly; an electrolyte injected into the battery can; and a sealing body sealing an open end of the battery can, wherein each of the positive electrode plate and the negative electrode plate includes a non-coated portion in which an active material layer is not formed, and at least a part of the non-coated portion of the positive electrode plate or the negative electrode plate defines an electrode tab, and wherein a volume occupied by the electrolyte is 101% by volume or more and 119% or less based on the total pore volume of the positive electrode plate, the negative electrode plate, and the separator.