Battery Insulating Sheet Layout to Suppress Partial Discharge
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Solution Overview
Problem
The formation of a short-circuit path due to water entry in batteries can cause partial discharge between the electrode assembly and the exterior package, leading to dielectric breakdown.
Innovation Solution
A battery design that includes a prismatic battery case with insulating sheet interposed between the electrode assemblies and the exterior package, using a specific configuration of current collectors and tab groups to prevent direct contact and minimize dielectric breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cut is formed in the insulating sheet to create clearance between the electrode assembly and exterior package, then assembly flexibility is improved, but dielectric strength deteriorates allowing partial discharge
Solution Approach 1:
A resin seal member is introduced as an intermediary component between the insulating sheet and the exterior package. This seal member fills the clearance created by the cut in the insulating sheet, maintaining dielectric strength and preventing partial discharge while allowing the insulating sheet to be cut for assembly flexibility. The resin seal member acts as a mediator that preserves electrical insulation properties despite the presence of the cut.
2Reliability
If water enters the battery forming a short-circuit path, then operational safety deteriorates, but this creates a need for enhanced insulation measures
Solution Approach 1:
The insulating sheet is designed as a thin film structure that can be cut to fit the battery assembly configuration. This thin film provides sufficient electrical insulation to prevent short-circuit paths formed by water entry, maintaining operational safety without requiring complex multi-layer insulation structures. The flexibility of the thin film allows it to conform to the battery components while providing effective insulation.
3Reliability
If the insulating sheet is made continuous without cuts, then dielectric strength is improved, but assembly and fitting flexibility deteriorates
Solution Approach 1:
The insulating sheet is pre-cut to the required shape and size before assembly, allowing it to be easily fitted around the electrode assembly and other battery components. The cut portions are designed to provide necessary clearances while the resin seal member is subsequently applied to restore dielectric strength. This preliminary cutting action enables both fitting flexibility and maintained insulation properties.
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 effectively suppresses partial discharge by ensuring electrical insulation, thereby enhancing the battery's operational safety and reliability.
Implementation Method 1
partial discharge due to dielectric breakdown between the electrode assembly and the exterior package through a clearance between the electrode assembly and the exterior package
Data Source
Figure 1
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Figure 3~4
AI summary
In an insulating sheet (50), a first left-side piece portion (520), a second left-side piece portion (521), a left-side bottom piece portion (522), a first left-side connection portion (523), and a second left-side connection portion (524) form a first communication path (530) for communicating inside and outside of the insulating sheet (50), the first communication path (530) having a first open end (531) at a position of an end of each of the first left-side connection portion (523) and the second left-side connection portion (524) on the opening (101) side of an exterior package (100). The first communication path (530) is located on a shortest reach path for an electrolyte solution (80) reaching, from the outside of the insulating sheet (50), an end portion (20e) of an electrode assembly (20) closest to a ridgeline portion of the exterior package (100) on the bottom portion (102) side and on the side of one of a pair of second side walls (104a, 104b).