Cell Module Equipotential Cooling Conduit Design

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Solution Overview

Problem

Cell modules cooled with deionized water conduits face issues with partial discharges due to conductivity differences, leading to high electrical potential differences and requiring extended distances or expensive insulation, which compromises compactness and shielding effectiveness.

Innovation Solution

A cell module design with electrically conductive material walls and connection members that maintain the same electrical potential as the enclosure, reducing the electrical potential difference between the cooling fluid and the module structure, allowing for shorter conduit distances and eliminating the need for expensive isolation materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the distance between water conducting isolating tubes and metallic parts of the cell module is extended to lower the electrical field strength to avoid partial discharges, then the risk of partial discharges is reduced, but the compactness of the cell module is compromised and the shielding effect is reduced

Engineering Contradiction:
Improverisk of partial dischargesVSAvoidcompactness of cell module
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The connection member is made of electrically conductive material and is connected to both the interior cooling conduit and the enclosure wall, establishing an equipotential connection. This ensures that the connection member and wall section are at the same electrical potential, eliminating the electrical potential difference that would otherwise exist between the cooling fluid and the enclosure. This resolves the contradiction by allowing the conduit to be positioned close to the metallic structure without creating harmful electrical fields, thus maintaining compactness while preventing partial discharges.

Inventive Principle:
Principle #12Equipotentiality

2Reliability

If the distance between water conducting isolating tubes and metallic parts of the cell module is extended to lower the electrical field strength to avoid partial discharges, then the risk of partial discharges is reduced, but the shielding effect of the metallic enclosure for all devices inside the cell module is reduced

Engineering Contradiction:
Improverisk of partial dischargesVSAvoidshielding effect against electrical fields
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By establishing an equipotential connection between the cooling conduit and the enclosure through the conductive connection member, the invention eliminates the need for large distances to reduce electrical field strength. The connection member acts as an electrical bridge that equalizes potential, allowing the conduit to remain close to the enclosure while maintaining both partial discharge prevention and effective electromagnetic shielding.

Inventive Principle:
Principle #12Equipotentiality

3Reliability

If expensive isolating material is used for the conduits and connections to avoid partial discharges, then the risk of partial discharges is reduced, but the cost and complexity of the cell module increases

Engineering Contradiction:
Improverisk of partial dischargesVSAvoidcomplexity of insulation system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces complex expensive isolating material systems with a simple equipotential connection using conductive material. The connection member made of electrically conductive material connected to both the conduit and enclosure creates an electrical bridge that eliminates potential differences, achieving partial discharge prevention through electrical potential equalization rather than through complex insulation layers.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The invention extracts and eliminates the need for expensive isolating material by introducing a conductive connection member that creates an equipotential relationship. This removes the harmful electrical field conditions without requiring the previously necessary insulating materials, simplifying the overall system while maintaining reliability.

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

This design reduces the risk of partial discharges, enables a more compact and cost-effective module structure by minimizing the distance between conduits and the enclosure, while maintaining effective shielding against electrical fields.

Implementation Method 1

The conductivity of the cooling water... is much higher than that of the isolating material of the conduit in which it is transported. The water content of the conduit connecting a metallic part in the cell module and a grounded part acts like a resistor.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The water content of the conduit connecting a metallic part in the cell module and a grounded part (or a point between the metallic part in the cell module and the grounded part) acts like a resistor. The electrical potential of the deionized water inside the conduit decreases between the metallic part in the cell module and the grounded part.

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

the at least one connection member and the wall section are at the same electrical potential... reducing the electrical potential difference between the cooling fluid and the module structure

Methodology Applied
Scientific EffectElectrical potential equalization: Electrostatic Induction

Data Source

PatentEP3476187B1Cell module for modular converter
Publication Date: 2020.06.03 ABB POWER GRIDS SWITZERLAND AG
  • EP3476187B1 patent drawingFigure 1
  • EP3476187B1 patent drawingFigure 2
  • EP3476187B1 patent drawingFigure 3~4

AI summary

Cell module (10) for a modular converter, the cell module (10) comprising an enclosure (12) having a wall section (20) of electrically conductive material and an opening (36) in the wall section (20); at least one interior cooling conduit (28) for distributing a dielectric cooling fluid to and/or from an electronic component (18) arranged within the enclosure (12); at least one exterior cooling conduit (26) of dielectric material for delivering the dielectric cooling fluid to or from a region outside of the enclosure (12); and at least one connection member (34) of electrically conductive material connecting the at least one interior cooling conduit(28) to a respective exterior cooling conduit (26) to establish a fluid connection between the electronic component (18) and the region outside of the enclosure (12) through the opening (36); wherein the at least one connection member (34) and the wall section (20) are at the same electrical potential; and wherein the at least one connection member (34) is provided inside of and close to the wall section (20) of the enclosure (12).