Separator With Asymmetric Thermal Bonding For Wound Battery Tension
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Solution Overview
Problem
In energy storage devices with wound electrode assemblies, the heat-resistant coated separators are difficult to bond effectively at the winding end point, leading to potential slackness and performance degradation due to their poor thermal bonding properties.
Innovation Solution
The use of a separator with distinct thermal bonding properties, where one surface has superior thermal bonding capabilities, allowing for secure bonding to an insulation sheet, which is then wound around the outermost layer to maintain tension and prevent performance decline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat-resistant coated separator is used to improve thermal stability, then temperature resistance is improved, but thermal bonding capability deteriorates
Solution Approach 1:
The separator is designed with different surface properties on different sides: one surface has a heat-resistant coating for thermal stability, while the other surface maintains good thermal bonding properties for secure attachment to the insulation sheet. This local differentiation resolves the contradiction by assigning different functional qualities to different regions of the same component.
Solution Approach 2:
The separator's functionality is segmented into two distinct surfaces with different properties. The first surface provides heat resistance for thermal stability, while the second surface provides bonding capability for mechanical attachment. This segmentation allows the separator to simultaneously satisfy both requirements that would be contradictory in a uniform material.
2Stability of the object's composition
If the separator surface with heat-resistant coating is used for bonding, then thermal stability is improved, but bonding reliability deteriorates
Solution Approach 1:
Different surfaces of the separator are assigned different functional qualities: one surface is optimized for thermal stability with heat-resistant coating, while the other surface is optimized for bonding reliability with good thermal bonding properties. This local quality differentiation ensures that each function is performed by the most suitable surface.
Solution Approach 2:
The separator acts as an intermediary component between the wound electrode assembly and the insulation sheet. By providing a dedicated bonding surface with appropriate thermal bonding properties, it mediates the connection while preserving the heat-resistant properties needed for thermal stability on the other surface.
3Duration of action of stationary object
If thermal bonding is used to fix the separator, then durability is improved, but bonding effectiveness deteriorates when the separator has poor thermal bonding properties
Solution Approach 1:
The separator is designed with one surface having superior thermal bonding properties specifically for the bonding operation during manufacturing. This localized bonding-friendly surface enables effective thermal bonding to the insulation sheet, while the other surface maintains heat-resistant properties for long-term durability in the battery's internal environment.
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 approach ensures that tension is maintained at the winding end point, preventing slackness and performance degradation by utilizing the superior thermal bonding surface for secure attachment to the insulation sheet, even when the heat-resistant layer is resistant to thermal bonding.
Implementation Method 1
the separator is bonded to the insulation sheet via the first surface thereof, the first surface having thermal bonding properties superior to thermal bonding properties of the second surface
Data Source
AI summary
Provided is an energy storage device which employs the use of a separator provided with a layer having poor thermal properties such as a heat resistant coated layer and is capable of inhibiting a decrease in performance. The energy storage device includes: a wound body including a positive electrode, a negative electrode, and separators which are layered and wound, the separators being interposed between the positive electrode and the negative electrode and having a first surface and a second surface, the first surface having thermal bonding properties superior to thermal bonding properties of the second surface; and an insulation sheet wound around an outermost layer of the wound body. At least one of the separators is bonded to the insulation sheet via the first surface thereof.