Curved Secondary Battery Two-Stage Shaping Method
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Solution Overview
Problem
Existing methods for manufacturing curved secondary batteries face challenges in minimizing stress and preventing deformation during the shaping process, which can lead to wrinkles in the pouch and removal of active materials, especially when forming smaller curvature radii.
Innovation Solution
A two-stage shaping method is employed, where a flat secondary battery is first pressed in a first jig to form a primarily-shaped battery with a larger curvature radius, and then in a second jig to achieve a smaller second curvature radius, using controlled pressures and temperatures to minimize stress and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a single-stage shaping method is used to form small curvature radius, then the curvature radius is reduced, but stress concentration and deformation increase causing pouch wrinkles and active material removal
Solution Approach 1:
The shaping process is divided into multiple stages with progressively decreasing curvature radii. The first shaping stage uses a first jig to form a first curvature radius, and the second shaping stage uses a second jig to form a smaller second curvature radius. This segmentation allows stress to be distributed across multiple steps rather than concentrated in a single step, preventing pouch deformation and active material removal while achieving the desired small final curvature radius.
2Shape
If high pressure is applied to achieve small curvature radius, then the curvature radius is reduced, but stress increases causing damage to battery components
Solution Approach 1:
The first shaping operation is performed as a preliminary action before the second shaping operation. The first jig pre-forms the battery with a larger curvature radius, creating a gradually deformed structure that is more resistant to stress concentration. This preliminary deformation prepares the battery for the subsequent second shaping stage, allowing the final small curvature radius to be achieved with reduced stress and without damaging the battery components.
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 allows for the efficient formation of curved secondary batteries with smaller curvature radii while reducing stress and deformation, thereby minimizing damage and maintaining the integrity of the battery components.
Implementation Method 1
Primary shaping the secondary battery may include heating the flat secondary battery with heat from the first jig
Implementation Method 2
The second jig may be located in an oven, and may include a second upper jig and a second lower jig such that the second upper jig and the second lower jig are separate from each other. The second jig may be formed of a metal, and the oven may heat the second jig to about 50° C. to about 75° C.
Implementation Method 3
Pressing the flat secondary battery may include the first jig pressing the flat secondary battery with a first pressure of about 1 kgF/cm2 to about 5 kgF/cm2 for a time period of about 3 seconds to about 30 seconds
Implementation Method 4
Secondary shaping the secondary battery may include the second jig pressing the primarily-shaped secondary battery with a second pressure of about 3.5 kgF/cm2 to about 8 kgF/cm2 for a time period of about 10 minutes to about 4 hours
Data Source
AI summary
A method of manufacturing a curved secondary battery, the method including preparing a flat secondary battery such that the flat secondary battery includes an electrode assembly and a pouch accommodating the electrode assembly; primary shaping the secondary battery such that the primary shaping includes disposing the flat secondary battery in a first jig, and pressing the flat secondary battery to form a primarily-shaped secondary battery such that the primarily-shaped secondary battery has a first curvature radius; secondary shaping the secondary battery such that the secondary shaping includes disposing the primarily-shaped secondary battery in a second jig, and pressing the primarily-shaped secondary battery to form a secondarily-shaped secondary battery having a second curvature radius; and maintaining the secondarily-shaped secondary battery after forming thereof in the second jig for a predetermined time period.