Lithium Ion Battery Extruded Resin Length Control
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Solution Overview
Problem
Laminated type lithium ion batteries suffer from decreased insulation resistance due to stress concentration in extruded resin portions with varying lengths, leading to insulation breakdown.
Innovation Solution
Controlling the difference between the maximum and minimum lengths of the extruded resin portion within a specific range (0.0 mm to 1.0 mm) in the heat-fusion resin layer, ensuring stable insulation properties by adjusting the heat fusion conditions during sealing, and maintaining an obtuse angle between the extruded resin portion and the non-fusion portion to prevent electrolyte infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heat-fusion resin layer is sealed during battery manufacturing, then sealing reliability is improved, but stress concentration in extruded resin portions causes insulation breakdown
Solution Approach 1:
The patent controls the length of extruded resin portions by adjusting heat fusion parameters (temperature, time, pressure) to keep lengths within 0.5-2.0mm and length differences within 1.0mm. This parameter control prevents stress concentration that leads to insulation breakdown while maintaining sealing reliability.
Solution Approach 2:
The patent removes extruded resin portions that exceed the specified length limits before they can cause insulation breakdown. This preventive measure eliminates potential stress concentration points beforehand, ensuring long-term insulation reliability.
2Reliability
If extruded resin portions are removed to prevent insulation breakdown, then insulation resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes heat fusion parameters to produce extruded resin portions within acceptable length ranges (0.5-2.0mm) directly during sealing. This reduces or eliminates the need for additional removal operations, maintaining insulation resistance while minimizing manufacturing complexity.
3Stability of the object's composition
If the length of extruded resin portions is controlled within a specific range, then stress distribution is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges for heat fusion (temperature, time, pressure) that consistently produce extruded resin portions within the 0.5-2.0mm length range. By optimizing these parameters, the patent achieves good stress distribution without requiring excessive manufacturing precision.
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 controlled extruded resin portion length and angle configuration enhance insulation resistance, prevent corrosion, and maintain long-term sealing reliability, thereby providing a lithium ion battery with excellent insulating properties and improved durability against external stresses.
Implementation Method 1
an outer package which includes at least a heat-fusion resin layer (21) and a barrier layer (23), and in which the battery main body (10) is sealed
Data Source
AI summary
A lithium ion battery (100) of the invention includes a battery main body (10) which includes one or more power generation elements configured by laminating a positive electrode layer, an electrolyte layer, and a negative electrode layer, in this order; an outer package (20) which includes at least a heat-fusion resin layer (21) and a barrier layer (23), and in which the battery main body (10) is sealed; and a pair of electrode terminals (30), each of which is electrically connected to the battery main body (10) and at least a part of which is exposed to the outside of the outer package (20). The outer package (20) includes an accommodation portion (25) which accommodates the battery main body (10), a joint portion (27) where the heat-fusion resin layers (21) positioned on a peripheral portion of the accommodation portion (25) are joined with each other directly or through the electrode terminal (30), and an extruded resin portion (29) which is formed by extrusion of a part of the heat-fusion resin layer (21) of the joint portion (27) from the joint portion (27) to the accommodation portion (25) side, and a difference (Lmax−Lmin) between a maximum length Lmax and a minimum length Lmin of the extruded resin portion (29) is equal to or greater than 0.0 mm and equal to or smaller than 1.0 mm.