Axial Diode Junction Box with Flat-Pin Welding for Heat Dissipation

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Solution Overview

Problem

The existing junction boxes face challenges with high production costs and complex mounting processes due to the use of modular diodes for high currents, which require additional packaging and testing, and the heat dissipation of diodes is inadequate, affecting their lifespan and electrical safety.

Innovation Solution

An axial diode junction box design featuring an axial diode with first and second pins that have flat portions for direct welding with bus bars, reducing the need for extra connection members and enhancing heat dissipation, while being suitable for high currents (20A-35A).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If modular diodes are used for high currents, then the current handling capability is improved, but the production cost and device complexity increase due to additional packaging and testing requirements

Engineering Contradiction:
Improvecurrent handling capabilityVSAvoidpackaging and testing complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent uses standard axial diodes instead of expensive modular diodes. The axial diodes are designed with flat portions on their pins that allow direct welding to bus bars, eliminating the need for complex modular packaging and testing infrastructure. This approach treats the diode as a simple, replaceable component rather than requiring investment in specialized modular diode handling equipment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent combines the diode body with the mounting structure by integrating the flat portions directly onto the diode pins. This merging eliminates the need for separate connection members (such as conductive sheets) and reduces the number of assembly steps, thereby simplifying the overall device complexity while maintaining high current handling capability.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If modular diodes are used for high currents, then the current handling capability is improved, but the production cost increases due to specialized packaging and testing devices

Engineering Contradiction:
Improvecurrent handling capabilityVSAvoidproduction cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive axial diodes with standard configurations rather than costly modular diodes. The flat portions are created through simple stamping or bending processes during standard diode manufacturing, avoiding the need for expensive specialized packaging and testing equipment required for modular diodes, thereby significantly reducing production costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the physical parameters of standard axial diodes by adding flat portions to the pins through stamping or bending. This parameter change allows direct welding capability and improved heat dissipation without requiring a complete transition to modular diode architecture, thus maintaining cost-effectiveness while achieving high current handling.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional axial diodes are used, then the production cost is low, but the heat dissipation efficiency is insufficient affecting diode lifespan

Engineering Contradiction:
Improveproduction costVSAvoiddiode lifespan
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent changes the geometric parameters of the diode pins by creating flat portions through stamping or bending. This parameter modification increases the surface area for heat dissipation and provides direct welding surfaces for thermal and electrical connection to bus bars, thereby improving heat dissipation efficiency and extending diode lifespan while maintaining low production costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from circular pin cross-sections to flat portions, effectively changing the dimensional characteristics of the pin surfaces. This dimensional change creates larger surface areas for heat dissipation and welding contact, improving thermal management without adding complex three-dimensional structures or increasing manufacturing complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of manufacture

If conventional axial diodes are used, then the production cost is low, but the mounting process complexity increases due to need for extra connection members

Engineering Contradiction:
Improveproduction costVSAvoidmounting process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the connection function directly into the diode structure by creating flat portions on the pins that serve as welding surfaces. This integration eliminates the need for separate connection members such as conductive sheets or additional mounting hardware, thereby simplifying the mounting process while maintaining cost-effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the connection member function from the mounting process and incorporates it directly into the diode structure itself. The flat portions on the pins perform both the electrical connection and mechanical attachment functions, removing the need for extra connection members and simplifying the overall mounting process.

Inventive Principle:
Principle #2Taking out (Extraction)

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 simplifies the mounting process, reduces production costs, and improves heat dissipation, making it suitable for high currents, thus replacing modular diodes and enhancing power utilization and reliability.

Implementation Method 1

The first flat portion and the second flat portion can increase heat dissipation areas of the axial diode and shorten heat dissipation paths (e.g., an original heat dissipation path from the pin to the conductive sheet is shortened to a direct heat dissipation by the pin), improve a heat dissipation effect

Methodology Applied
Scientific EffectHeat dissipation: Conduction (thermal)

Implementation Method 2

the first flat portion and the second flat portion can be directly used as welding surfaces that can be directly welded with bus bars

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4203302B1Axial diode junction box and manufacturing method therefor
Publication Date: 2025.11.19 ZERUN CO LTD
  • EP4203302B1 patent drawingFigure 1~2
  • EP4203302B1 patent drawingFigure 3~4
  • EP4203302B1 patent drawingFigure 5~6

AI summary

The present application discloses an axial diode junction box and a method for manufacturing the same, comprising an axial diode and a junction box body, wherein the axial diode is mounted inside the junction box body; the axial diode comprises a diode body, a first pin, and a second pin, one end of the diode body is connected to the first pin, the other end of the diode body is connected to the second pin, and a direction where the diode body is close to the junction box body is defined as a front direction; the first pin comprises a first connection portion and a first flat portion, one end of the first connection portion is connected to one end of the diode body, and the other end of the first connection portion is connected to the first flat portion; the second pin comprises a second connection portion and a second flat portion, one end of the second connection portion is connected to the other end of the diode body, and the other end of the second connection portion is connected to the second flat portion; and the diode body is clamped to the junction box body. The present application can simplify a production process, reduce a product cost, improve the product reliability, and improve the production efficiency of a production line.