Electric Axle Power Module Layout for Uniform Semiconductor Loading

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Solution Overview

Problem

Conventional power modules for electric axle drives in motor vehicles often experience uneven current distribution due to the design of leadframes, leading to non-uniform loading of semiconductor elements, which can result in inefficiencies and reduced performance.

Innovation Solution

A power module design featuring a termination substrate with isolated contact portions, where power semiconductor elements have centralized power-source interfacing, allowing for uniform current distribution and connection of control terminals to a corresponding terminal pin, enabling efficient electrical and thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional leadframe design is used for power module, then the module can be manufactured with standard leadframe processes, but the current distribution between semiconductor elements becomes uneven, causing non-uniform loading

Engineering Contradiction:

Improvemanufacturability of leadframeVSAvoiduniformity of current distribution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The termination substrate is divided into multiple isolated contact portions, each serving specific semiconductor elements. This segmentation allows independent optimization of current paths for different semiconductor elements, ensuring uniform current distribution while maintaining manufacturability through standardized substrate processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The termination substrate acts as an intermediary between the power source and semiconductor elements, providing isolated contact portions that mediate current distribution. This intermediary structure enables uniform current flow to each semiconductor element while maintaining compatibility with standard manufacturing processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If semiconductor elements are positioned according to leadframe manufacturability, then the module can be produced efficiently, but the current conduction becomes non-uniform in the power source region

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoiduniformity of semiconductor loading

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Different regions of the termination substrate are designed with different properties: isolated contact portions for uniform current distribution, centralized power terminal for efficient power source interfacing, and distributed control terminals for proper semiconductor control. This local quality differentiation achieves both manufacturing efficiency and reliable uniform loading.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The isolated contact portions on the termination substrate are designed to create equipotential regions that ensure uniform current distribution to each semiconductor element. This equipotential design maintains manufacturing efficiency while ensuring reliable and uniform semiconductor loading conditions.

Inventive Principle:

Principle #12Equipotentiality

3Manufacturing precision

If a centralized power terminal is implemented, then uniform current distribution between semiconductor elements is achieved, but the module design becomes more complex compared to conventional leadframe

Engineering Contradiction:

Improveuniformity of current distributionVSAvoidmodule structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The termination substrate serves multiple functions simultaneously: it provides isolated contact portions for uniform current distribution, centralized power terminal for power source interfacing, and distributed control terminals for semiconductor control. This multi-functionality reduces overall module complexity while achieving uniform current distribution.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The termination substrate merges multiple functions into a single component: current distribution, power source connection, and control terminal integration. This merging approach simplifies the overall module structure while maintaining uniform current distribution, reducing the need for separate leadframe and termination components.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20240022180A1Power module for a current converter for an electric axle drive of a motor vehicle

Publication Date: 2024.01.18 ZF FRIEDRICHSHAFEN AG

AI summary

A power module for a current converter for an electric drive of a motor vehicle comprises a termination substrate having electrical contact portions that are electrically isolated from one another, a plurality of power semiconductor elements arranged on the termination substrate, each having a first terminal, a second terminal, and a control terminal, the first terminals of all the power semiconductor elements being electrically connected to a first contact portion of the termination substrate. The power module also includes a first electrical termination, which is electrically connected to the first contact portion of the termination substrate, and a second electrical termination, which is electrically connected to the second terminals of all the power semiconductor elements, the second termination being arranged centrally between and/or above the power semiconductor elements, and an electrical control termination, which is electrically connected to the control terminals of all the power semiconductor elements.