Tandem Solar Cell Short-Circuit Detection Using Reference Potentials

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Solution Overview

Problem

Existing solar power generation systems with tandem solar cell modules face challenges in detecting short circuits between different types of solar cell submodules due to voltage differences, which can lead to inefficiencies and potential damage.

Innovation Solution

A solar power generation system with a short-circuit detection device that measures potential differences between the bottom-side and top-side solar cell submodules in tandem solar cell modules, using ground fault detection circuits and a control unit to identify and locate short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If tandem solar cell modules with different photoelectric conversion layers are stacked to improve conversion efficiency, then the use of energy by stationary object is improved, but the difficulty of detecting and measuring increases due to voltage differences between submodules

Engineering Contradiction:

Improveconversion efficiencyVSAvoidshort circuit detection difficulty

Core Design Contradiction:

Use of energy by moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The detection method segments the measurement process by separately measuring the voltage of each submodule relative to a common reference potential. This allows independent measurement of each submodule's voltage without being affected by voltage differences between submodules, enabling accurate short circuit detection in tandem solar cell modules while maintaining high conversion efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A reference potential is introduced as an intermediary measurement point. By measuring each submodule's voltage relative to this common reference rather than directly comparing submodule voltages, the system can detect short circuits without being influenced by the inherent voltage differences between different photoelectric conversion layers

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If ground fault detection methods using detection resistors are used to detect ground faults, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improveground fault detection capabilityVSAvoiddetection circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The reference potential measurement method serves multiple functions: it detects ground faults, detects short circuits between submodules, and provides voltage measurement for both positive and negative terminals. This multi-functional approach improves reliability without requiring separate detection circuits for each function, thereby reducing overall device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own terminal voltages and a common reference potential to perform self-diagnosis for both ground faults and inter-submodule short circuits. This self-service capability eliminates the need for external complex detection equipment while maintaining high reliability

Inventive Principle:

Principle #25Self-service

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

Effectively detects and locates short circuits in tandem solar cell modules, enhancing system efficiency and preventing damage by identifying voltage imbalances.

Implementation Method 1

a solar cell string in which M number of 4-terminal tandem solar cell modules each including a bottom-side solar cell submodule and a top-side solar cell submodule are electrically connected

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20260025099A1Photovoltaic system and short circuit detection method for photovoltaic system

Publication Date: 2026.01.22 KANEKA CORP

AI summary

A photovoltaic system that detects a short circuit in tandem solar cell modules, and includes a solar cell string in which a number of tandem solar cell modules are connected; and a short circuit detector. A number of bottom-side solar cell submodules constitute a series-connected, bottom-side solar cell string, and a number of top-side solar cell submodules constitute a series-connected, top-side solar cell string. The short circuit detector measures the potential difference Vps+ between a positive potential terminal of the bottom-side solar cell string and a positive potential terminal of the top-side solar cell string, measures the potential difference Vps− between a negative potential terminal of the bottom-side solar cell string and a negative potential terminal of the top-side solar cell string, and detects a short circuit in the tandem solar cell modules if the absolute values of the potential differences Vps+ and Vps− are greater than 0 V.