Cylindrical Battery Venting With a Tapered Terminal Cap
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Solution Overview
Problem
Existing cylindrical batteries face issues with gas discharge efficiency due to gas accumulation in the sealing assembly, leading to impaired operation of the safety vent, especially when internal pressure increases from abnormal heat generation.
Innovation Solution
A cylindrical battery design featuring a terminal cap with a tapered portion projecting toward the electrode assembly, guiding high-temperature gas efficiently to a rupturable portion in the bottom of the exterior housing can, ensuring smooth operation of the safety vent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a safety vent with large discharge area is provided in the bottom portion of the exterior housing can, then the capability to discharge gas generated inside the battery is improved, but gas accumulation in corner portions of the sealing assembly and gaps between members prevents the safety vent from operating smoothly
Solution Approach 1:
A gas guide member is introduced as an intermediary component between the electrode assembly and the sealing assembly. This guide member directs gas flow from the electrode assembly toward the safety vent, preventing gas accumulation in corner portions and gaps of the sealing assembly, thereby ensuring the safety vent operates smoothly even with large discharge area
Solution Approach 2:
The gas guide member extends in the axial direction from the electrode assembly toward the sealing assembly, creating a three-dimensional gas flow path. This dimensional approach guides gas along a specific trajectory, preventing it from stagnating in two-dimensional corner portions and gaps of the sealing assembly
2Reliability
If the strength of the sealing assembly is insufficient to withstand internal pressure from abnormal heat generation, then gas can be discharged, but the sealing assembly deflects and prevents high-temperature gas from smoothly flowing to the bottom portion
Solution Approach 1:
The sealing assembly is segmented into multiple components: a terminal cap, a terminal plate, and a gas guide member. This segmentation allows each component to perform its specific function - the gas guide member directs gas flow while the terminal cap and plate provide structural support, preventing deflection that would block gas flow to the safety vent
Solution Approach 2:
The gas guide member serves as a mediator that maintains gas flow pathways even when the sealing assembly experiences pressure-induced deflection. It ensures high-temperature gas can still reach the safety vent by providing a dedicated flow channel independent of sealing assembly deformation
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 enhances gas discharge efficiency by smoothly guiding high-temperature gas to the rupturable portion, improving safety by ensuring the safety vent operates effectively, even under high internal pressure conditions.
Implementation Method 1
the terminal cap has a tapered portion that projects toward the electrode assembly side and is tapered toward a hollow portion of the electrode assembly
Data Source
Figure 1
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AI summary
This cylindrical battery (10) is provided with: a bottomed cylindrical exterior can (16) that accommodates an electrode body (14); and a sealing body (17) that is crimped and secured to an opening of the exterior can (16) with a gasket (28) therebetween. The external can (16) has thin-walled easily-breakable sections (70) on a bottom (68) thereof, and the sealing body (17) has a terminal cap (27) for sealing the opening of the external can (16). The terminal cap (27) has a tapered part (27c) that protrudes toward the electrode body (14) and becomes tapered toward a hollow space (14a) of the electrode body (14). A tip (53) of the tapered part (27c) is positioned closer to the electrode body (14) than a part of the sealing body (17) other than the tapered part (27c).