Insulated Bus Bar Coating for Complex Shapes and Corner Peeling

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Solution Overview

Problem

Existing bus bars with ceramic tapes face challenges in maintaining insulation and heat resistance due to complex shapes, tape peeling, and temperature changes, especially in miniaturized power storage devices, leading to potential insulation failures and safety risks.

Innovation Solution

A bus bar design with an insulating film having a thicker film thickness on corner portions and an R-shaped outer surface, combined with inorganic compounds and a silicone-based material, is produced using dip coating to ensure robust insulation and heat resistance, even in complex shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ceramic tape is wound around the bus bar body to provide insulation and heat resistance, then the insulation property and heat resistance are improved, but the manufacturing complexity increases and the insulating film may peel off when the bus bar has a complicated shape

Engineering Contradiction:
Improveinsulation propertyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical winding process of ceramic tape with a chemical coating process. The insulating film is formed by applying an insulating coating material to the bus bar body and drying it, eliminating the need for manual or automated tape winding operations. This substitution resolves the contradiction by maintaining insulation reliability while significantly reducing manufacturing complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and application method of the insulating material from pre-formed ceramic tape to a liquid or paste insulating coating material that can be applied conformally to complex geometries. This parameter change allows the coating to adapt to any bus bar shape without requiring complex winding operations, thereby reducing manufacturing complexity while maintaining insulation reliability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the bus bar is designed with a complicated shape to fit spatial limitations, then the adaptability to installation locations is improved, but the insulating film becomes difficult to apply uniformly and may peel off

Engineering Contradiction:
Improveadaptability to installation locationVSAvoiduniformity of insulating film
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the insulating material from rigid ceramic tape to a flowable coating material that can conform to complex geometries. This parameter change enables uniform coating application on bus bars with complicated shapes, maintaining manufacturing precision while preserving adaptability to various installation locations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The insulating coating material forms a flexible thin film that can conform to the complex surface geometry of the bus bar body. This flexible film structure adapts to any shape without peeling, resolving the contradiction between geometric adaptability and coating uniformity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Volume of moving object

If the bus bar is used in a narrow region or transported in mass production, then the space utilization is improved, but the corner portions may collide and the insulating film may be damaged

Engineering Contradiction:
Improvespace utilizationVSAvoidintegrity of insulating film
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies the insulating coating to the bus bar body in advance during the manufacturing process, forming a protective layer before the bus bar is subjected to transportation or installation. This preliminary protection prevents damage during subsequent handling, resolving the contradiction between compact usage and film integrity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The insulating coating material acts as a cushioning layer that absorbs impact energy during collisions of corner portions. This beforehand protection maintains the integrity of the insulating film even when bus bars collide during transportation or installation in narrow regions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Adaptability or versatility

If the bus bar operates under repeated temperature changes, then the operational flexibility is improved, but the temperature difference causes the insulating film to peel off

Engineering Contradiction:
Improveoperational flexibilityVSAvoidadhesion of insulating film
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent changes from a rigid ceramic tape with poor thermal expansion matching to a polymer-based insulating coating that can accommodate thermal expansion and contraction. This parameter change maintains adhesion stability under repeated temperature changes while preserving operational flexibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The insulating coating material is formulated as a composite containing inorganic fillers (such as alumina, silica, or mica) dispersed in a polymer matrix. This composite structure combines the thermal stability of inorganic materials with the flexibility and adhesion of polymers, resolving the contradiction between operational flexibility and adhesion stability under temperature cycling.

Inventive Principle:
Principle #40Composite materials

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 film peeling and enhances insulation and heat resistance, ensuring high safety in abnormal states by minimizing damage from collisions and temperature changes.

Implementation Method 1

a drying step of drying the insulating coating material to form the insulating film

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

the bus bar is required to have an insulation property and heat resistance

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4700800A1Bus bar and method for producing same, and power storage device
Publication Date: 2026.02.25 IBIDEN CO LTD
  • EP4700800A1 patent drawingFigure 1
  • EP4700800A1 patent drawingFigure 2~3
  • EP4700800A1 patent drawingFigure 4~5

AI summary

To provide a bus bar in which an insulating film is formed in a desired region even when a bus bar body has a complicated shape, and peeling off or the like of the insulating film can be suppressed, and a method for producing the same. A bus bar (20) includes a bus bar body (25) and an insulating film (10) formed on a surface of the bus bar body (25). The bus bar body (25) includes a pair of main surface portions (25a) facing each other, a plurality of end surface portions (25b) connecting the main surface portions (25a) facing each other, and corner portions (25c) formed between the main surface portions (25a) and the end surface portions (25b). An outer surface of the insulating film (10) formed on the corner portion (25c) of the bus bar body (25) has an R shape. A film thickness of the insulating film (10) formed on the corner portion (25c) of the bus bar body (25) is larger than a film thickness of the insulating film (10) formed on the main surface portion (25a) of the bus bar body (25).