Laser-Welded Copper Insert Cooler Unit for Leak-Safe Power Module Cooling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cooler units for power modules in automotive inverters face challenges in achieving stable coupling and reliable heat dissipation, often requiring complex clamping mechanisms and additional sealing elements that can lead to reliability issues due to thermal cycling and coolant leakage.

Innovation Solution

A cooler unit design featuring a copper insert laser-welded to an aluminum housing, with a recessed structure and precise welding to ensure secure coupling and effective heat dissipation, eliminating the need for additional sealing elements and minimizing thermal impact on adjacent components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional cooler units use mechanical clamping mechanisms and additional sealing elements, then coupling stability is improved, but device complexity increases and reliability deteriorates due to thermal cycling and coolant leakage

Engineering Contradiction:
Improvecoupling stabilityVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the coupling function and sealing function into a single integrated structure. The recess in the housing directly receives and secures the insert through geometric coordination, eliminating the need for separate clamping mechanisms and sealing elements. This integration reduces structural complexity while maintaining coupling stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates unnecessary components (clamping mechanisms and additional sealing elements) from the conventional cooler unit design. By using the recess-insert geometric coordination system, the coupling is achieved without these extra parts, simplifying the overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If conventional cooler units use mechanical clamping mechanisms, then coupling stability is improved, but reliability deteriorates due to thermal cycling and coolant leakage

Engineering Contradiction:
Improvecoupling stabilityVSAvoidoperational reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The coupling and sealing functions are merged into the geometric coordination between the recess and insert. This integrated approach eliminates interfaces between separate components, reducing potential failure points from thermal cycling and coolant leakage, thereby improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By removing additional sealing elements and clamping mechanisms, the patent eliminates the reliability issues associated with these components under thermal cycling conditions. The simple geometric fit between recess and insert provides both coupling stability and sealing without the failure modes of complex mechanical systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If copper insert is laser welded to aluminum housing, then heat dissipation efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidwelding precision
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent uses a composite structure with copper insert and aluminum housing, joining materials with different thermal properties. The copper provides superior heat dissipation at the insert location, while the aluminum housing offers good overall thermal management. The laser welding process enables reliable joining of these dissimilar metals to achieve the desired thermal performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The copper insert is strategically placed in the recess where heat dissipation is most critical. The laser welding is applied locally at the welding areas (edges or peripheral regions) rather than across the entire component, concentrating manufacturing precision requirements only where needed for secure attachment while maintaining overall assembly feasibility.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If welding areas are formed at edge or peripheral regions, then manufacturing ease is improved, but structural strength may deteriorate

Engineering Contradiction:
Improvewelding easeVSAvoidjoint strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The welding process is segmented to occur at specific edge or peripheral regions rather than across the entire insert-housing interface. This segmentation allows for easier manufacturing by concentrating welding operations at accessible locations while the geometric coordination of the recess and insert provides distributed mechanical support throughout the assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The combination of copper insert and aluminum housing with edge-based laser welding creates a composite structure where the welding provides localized strong attachment at the periphery, while the geometric fit and material properties of both components contribute to overall joint strength and structural integrity.

Inventive Principle:
Principle #40Composite materials

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 design provides a stable, reliable, and efficient heat dissipation system with reduced thermal resistance and improved mechanical stability, allowing for thinner baseplates and cost-effective assembly without compromising thermal performance.

Implementation Method 1

The at least one insert is arranged inside the recess and laser welded to the housing

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

The at least one insert comprises copper and is arranged inside the recess and laser welded to the housing such that during operation the coolant flows through the flow channel and around the lower part of the at least one insert

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the coolant flows through the flow channel and around the lower part of the at least one insert

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4184567B1Cooler unit, semiconductor device and method for manufacturing a cooler unit
Publication Date: 2026.01.28 HITACHI ENERGY LTD
  • EP4184567B1 patent drawingFigure 1
  • EP4184567B1 patent drawingFigure 2
  • EP4184567B1 patent drawingFigure 3

AI summary

A cooler unit (1) for liquid cooling of a power module (30) comprises at least one insert (10) that includes an upper part (15) and a lower part (16) and that is configured to be coupled to the power module (30) with the upper part (15). The cooler unit (1) further comprises a housing (20) that limits an internal flow channel (27) for a coolant and that comprises at least one recess (21) which penetrates a wall (25) of the housing (20) up to the flow channel (27) and which is configured in coordination with the at least one insert (10) geometrically, wherein the at least one insert (10) comprises copper and is arranged inside the recess (21) and laser welded to the housing (20) such that during operation the coolant flows through the flow channel (27) and around the lower part (16) of the at least one insert (10).