Power Module Shielding Layer for EV Drive Thermal Management

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Solution Overview

Problem

Existing power modules for electric vehicle drives face challenges with ineffective heat dissipation and insufficient galvanic separation between control electronics and power switches, leading to impaired functionality due to interference emissions and thermal resistance issues.

Innovation Solution

A power module design featuring a shielding layer with a thermally and electrically conductive support structure and insulation layer, which provides effective thermal coupling between high voltage regions of the control electronics and the heatsink while maintaining galvanic separation, enhancing cooling efficiency and protecting against thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shield is used to shield the control electronics from interference emissions, then the galvanic separation between control electronics and power switches is improved, but the thermal resistance between the control electronics and the heatsink increases significantly

Engineering Contradiction:

Improvegalvanic separationVSAvoidthermal resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent introduces an intermediate shielding layer composed of thermally conductive but electrically insulating materials (such as ceramic coatings or polymer-based thermal interfaces) between the control electronics and heatsink. This intermediary structure enables thermal energy to pass through while blocking electrical interference, thus simultaneously achieving effective shielding and thermal management

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material structures combining materials with different properties - specifically materials that exhibit high thermal conductivity but low electrical conductivity (such as aluminum oxide ceramics, boron nitride, or specialized thermal interface compounds). This composite approach allows the shielding layer to conduct heat away from control electronics while maintaining galvanic separation from power switches

Inventive Principle:

Principle #40Composite materials

2Speed

If the switching time of power switches is reduced using wide bandgap semiconductors, then the switching speed is improved, but interference emissions that couple into control electronics increase

Engineering Contradiction:

Improveswitching speedVSAvoidinterference emissions

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The shielding layer acts as an intermediary barrier between power switches and control electronics, absorbing and redirecting electromagnetic interference emissions generated by high-speed wide bandgap semiconductor switching, thereby protecting control electronics from noise while allowing the high switching speeds to be maintained

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful electromagnetic interference emissions into manageable thermal energy that can be conducted away through the thermally conductive shielding layer, transforming a harmful byproduct of high-speed switching into a controllable thermal management issue

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enables improved heat dissipation and effective cooling of high voltage regions, reducing the risk of thermal damage and maintaining the functionality of the power module by effectively managing heat losses and interference emissions.

Implementation Method 1

insulation layer (108), which is designed such that the heatsink (102) is thermally and electrically connected to the numerous first regions (112) of the control electronics (110)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11497146B2Power module for operating an electric vehicle drive with improved thermal conduction for drive electronics

Publication Date: 2022.11.08 ZF FRIEDRICHSHAFEN AG

AI summary

A power module for operating an electric vehicle drive, comprising power switches for generating an output current based on an input current; control electronics for controlling the power switches including a first region, to which a first electric potential is applied, and a second region, to which a second electric potential is applied, wherein the second electric potential is higher than the first electric potential; a heatsink for discharging heat generated by the power switches and the control electronics; a shielding layer for electrically shielding the control electronics placed between the heatsink and the control electronics, such that the control electronics lies on the shielding layer, and the shielding layer lies on the heatsink; wherein the shielding layer is designed to connect the heatsink thermally and electrically to the first region, and thermally to the second region, and electrically insulate it therefrom.