Single Junction Box Layout for Multi-String PV Module Connections

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Solution Overview

Problem

Existing photovoltaic (PV) modules require multiple junction boxes and increased assembly effort due to separate connection contacts for each cell arrangement, which complicates installation and sealing.

Innovation Solution

A photovoltaic module design featuring a single, elongated junction box housing that covers and contacts all connection contacts along a central line on the back of the module, simplifying assembly and providing additional stabilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate junction boxes are used for each cell arrangement, then each connection contact can be individually protected and contacted, but the assembly effort and complexity increase significantly

Engineering Contradiction:
Improveconnection contact protectionVSAvoidnumber of junction boxes
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple separate junction boxes for different cell arrangements are merged into a single common junction box that houses all connection contacts from multiple cell arrangements. This consolidation reduces the total number of junction boxes while maintaining individual protection and contact capability for each connection contact, thereby reducing assembly complexity without compromising reliability

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple separate junction boxes are used for each cell arrangement, then each connection can be independently managed, but the sealing and mounting effort increases

Engineering Contradiction:
Improveconnection sealingVSAvoidsealing and mounting effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple sealing and mounting operations for separate junction boxes are merged into a single sealing and mounting operation for one common junction box. The housing is sealed as a single unit and mounted once to the module rear side, significantly reducing the total sealing and mounting effort while maintaining proper sealing for all connection contacts

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If connection contacts are arranged at several different positions on the rear side, then the module geometry can be optimized, but the junction box arrangement becomes more complex

Engineering Contradiction:
Improvemodule geometryVSAvoidjunction box arrangement
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The common junction box is designed with universal capability to accommodate connection contacts from multiple cell arrangements at different positions along the rear side of the module. The housing and contact carrier are configured to receive and contact connection contacts regardless of their specific positions, allowing the module geometry to be optimized while keeping the junction box arrangement simple and unified

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If a common junction box is used for all connection contacts, then assembly effort is reduced, but the housing must cover a larger area

Engineering Contradiction:
Improveassembly effortVSAvoidjunction box housing area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The common junction box housing is segmented into multiple contact areas, each dedicated to specific connection contacts from different cell arrangements. This segmentation allows the housing to cover a larger area efficiently by organizing connection contacts in groups within distinct contact areas, reducing assembly effort while managing the housing area through structured layout

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4228153B1Photovoltaic module and connection box for a photovoltaic module
Publication Date: 2025.04.23 WEIDMULLER INTERFACE GMBH & CO
  • EP4228153B1 patent drawingFigure 1a~1b
  • EP4228153B1 patent drawingFigure 2a~2b
  • EP4228153B1 patent drawingFigure 2c~3a

AI summary

The invention relates to a photovoltaic module (1) with at least two cell arrangements that can be externally connected to terminal contacts (4). The groups of two terminal contacts (4) assigned to each cell arrangement are arranged along a line on the rear side of the photovoltaic module (1). The photovoltaic module (1) is characterized in that exactly one terminal box (11) is arranged on a rear side (3) of the photovoltaic module (1), which has a housing (111) that has at least one opening towards the rear side (3) for the passage of the terminal contacts (4), the housing (111) covering all terminal contacts (4) of the photovoltaic module (1). The invention further relates to a terminal box (11) for such a photovoltaic module (1), in which the housing (111) has an elongated shape, with all terminal contacts (4) arranged in a line along a longitudinal direction of the housing (111).