Switching Cell Connecting Structure for Low-Stray-Inductance Layout

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Solution Overview

Problem

In switching cells for hybrid or electric vehicles, the positioning of power modules and DC link capacitors side by side leads to increased stray inductance due to uncompensated magnetic fields, resulting from the distance between connecting tabs.

Innovation Solution

A connecting device is interposed between the power module and the DC link capacitor, featuring a connecting part in contact with one polarity tab and a covering part that offsets to cover the space between tabs, providing a current path and compensating magnetic fields while preventing short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power module and DC link capacitor are positioned side by side, then the layout flexibility and vehicle integration are improved, but the magnetic field compensation deteriorates leading to increased stray inductance

Engineering Contradiction:
Improvelayout flexibilityVSAvoidstray inductance
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

A connecting device is introduced as an intermediary component between the power module and DC link capacitor. This connecting device includes a connecting part that contacts the connecting tab and a covering part that extends to cover the space between connecting tabs of different polarities, thereby mediating the magnetic field interaction and enabling compensation while maintaining the side-by-side layout

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The covering part of the connecting device is offset from the connecting part perpendicularly to the connection plane, creating a three-dimensional structure. This dimensional offset allows the covering part to extend over the space between connecting tabs without interfering with the planar connection, enabling magnetic field compensation in the side-by-side configuration

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

2Ease of manufacture

If connecting tabs are separated by a space to maintain clearance and accommodate manufacturing, then the manufacturing ease and safety are improved, but the magnetic field compensation deteriorates

Engineering Contradiction:
Improvemanufacturing easeVSAvoidstray inductance
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The connecting device serves as a mediator that bridges the gap between separated connecting tabs. The covering part extends over the space between tabs, creating additional current paths that compensate for the magnetic fields generated by the necessary separation distance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connecting device is segmented into distinct functional parts: a connecting part for electrical contact with the connecting tab, and a covering part that extends to cover the space between tabs. This segmentation allows each part to perform its specific function while working together to reduce stray inductance

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If the connecting device has an offset between connecting part and covering part, then the magnetic field compensation is improved, but the device complexity increases

Engineering Contradiction:
Improvestray inductanceVSAvoiddevice complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The connecting device merges multiple functions into a single integrated component: electrical connection through the connecting part, magnetic field compensation through the covering part, and structural support. This merging reduces the need for separate components while achieving the offset configuration for effective compensation

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively reduces stray inductance and secures the connection between the power module and DC link capacitor, minimizing the risk of short circuits and improving the overall performance of the switching cell.

Implementation Method 1

the covering part covering at least the space between the connecting tabs, the covering part being offset from the connecting part perpendicularly to the connection plane... compensating magnetic fields to solve the stray inductance issues

Methodology Applied
Scientific EffectMagnetic field compensation: Magnetic Field

Data Source

PatentEP4475643A1Switching cell with connecting device
Publication Date: 2024.12.11 VALEO ELECTRIFICATION
  • EP4475643A1 patent drawingFigure 1
  • EP4475643A1 patent drawingFigure 2
  • EP4475643A1 patent drawingFigure 3

AI summary

The present invention relates to a switching cell (1) for an automotive vehicle, comprising at least one power module (2, 2A, 2B, 2C), a DC link capacitor (4), and a connecting device (22) between the power module (2, 2A, 2B, 2C) and the DC link capacitor (4), the power module (2) having at least one connecting tab of a first polarity and at least one connecting tab of a second polarity, the connecting tabs being in a same connection plane and separated by a space, the connecting device (22) comprising at least one connecting part (24, 24A, 24B) in contact with the connecting tab of the first polarity (14) and a covering part (26) covering the space between the connecting tabs, the covering part (26) being offset from the connecting part (24, 24A, 24B) perpendicularly to the connection plane.