Battery Pouch Wall Thickness Layout for Higher Energy Density
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Solution Overview
Problem
The energy density of lithium-ion batteries is insufficient due to the need for a thick pouch to form an indentation for the bare cell, which compromises the battery's capacity and size.
Innovation Solution
A pouch design with a first pouch body having a thicker first wall portion and a second pouch body with a thinner second wall portion, where the second wall portion's thickness is less than the first, allowing for a larger accommodation cavity that can house a larger electrode assembly and electrolyte solution, thereby increasing capacity and energy density while meeting miniaturization requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pouch is made thick to ensure indentation capability, then the pouch can form the required indentation for the bare cell, but the energy density of the lithium-ion battery is impaired
Solution Approach 1:
The pouch adopts different wall thicknesses at different locations: the first wall portion has a first thickness while the second wall portion has a second thickness that is less than the first thickness. This local differentiation allows the pouch to maintain sufficient indentation capability at the first wall portion while increasing the accommodation cavity volume at the second wall portion, thereby resolving the contradiction between indentation strength and energy density.
2Strength
If the pouch is made thick to ensure indentation capability, then the pouch can form the required indentation for the bare cell, but the accommodation space for the electrode assembly is reduced
Solution Approach 1:
The pouch structure differentiates wall thickness locally: the first wall portion maintains a greater thickness for indentation capability, while the second wall portion reduces thickness to maximize the accommodation cavity volume. This resolves the contradiction between structural strength and internal volume.
3Strength
If the pouch is made thick to ensure indentation capability, then the pouch can form the required indentation for the bare cell, but the overall dimensions of the electrochemical device are increased
Solution Approach 1:
The pouch uses non-uniform wall thickness distribution, being thicker only where indentation capability is needed and thinner elsewhere, which minimizes the overall dimensions of the electrochemical device while maintaining the required structural function.
Solution Approach 2:
The patent transitions from a uniform thickness design to a variable thickness design, adding dimensional variation in the wall thickness parameter. This allows the pouch to achieve both indentation capability and compact overall dimensions by strategically distributing material thickness in three-dimensional space.
Data Source
AI summary
A pouch includes a first pouch body and a second pouch body connected to each other. A first cavity is recessed in a first pouch body. A second pouch body covers the first cavity so that the first pouch body and the second pouch body jointly close around to form the accommodation cavity. The first pouch body includes a first wall portion oriented toward the second pouch body. The first wall portion includes a first wall face oriented toward the accommodation cavity and a third wall face oriented away from the accommodation cavity. A thickness of the first wall portion is H1. The second pouch body includes a second wall portion oriented toward the first pouch body. The second wall portion includes a second wall face oriented toward the accommodation cavity and a fourth wall face oriented away from the accommodation cavity.