Electric Work Vehicle PDU Layout for Safer Battery Cooling

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Solution Overview

Problem

Existing electric work vehicles, such as electric tractors, face challenges in efficiently distributing power and cooling their battery systems, which can affect performance and longevity.

Innovation Solution

The electric work vehicle incorporates a power distribution unit (PDU) with separate housings for positive and negative rails, strategically located battery strings connected through contactors, and an air cooling system with evaporators and ducts to manage temperature effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single housing is used for both positive and negative rails in the power distribution unit, then the device complexity is reduced, but the reliability and safety of power distribution deteriorate due to potential short circuits and heat accumulation

Engineering Contradiction:
ImprovePDU structure complexityVSAvoidPower distribution safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The power distribution unit is divided into separate housings for positive rails and negative rails. This segmentation prevents short circuits between opposite polarity rails, reduces heat accumulation by separating heat-generating components, and improves overall system reliability while maintaining manageable complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If battery modules are placed close together to reduce vehicle size, then the volume of the vehicle is reduced, but the cooling efficiency deteriorates due to insufficient air flow and heat dissipation

Engineering Contradiction:
ImproveVehicle volumeVSAvoidBattery temperature
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The battery housing is designed with differentiated local structures: insulation walls between adjacent battery modules to reduce heat transfer, and open-side designs at front and rear ends to maximize air flow. This local quality variation optimizes both thermal isolation and heat dissipation, enabling compact battery arrangement while maintaining effective cooling.

Inventive Principle:
Principle #3Local quality

3Temperature

If insulation walls are added between battery modules to improve cooling, then the cooling efficiency is improved, but the device complexity and space utilization deteriorate

Engineering Contradiction:
ImproveBattery cooling efficiencyVSAvoidBattery housing structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The battery housing is segmented into modular units with insulation walls positioned only where thermally critical. The modular design allows standardized components to be replicated, managing complexity through repetition rather than unique custom parts for each section.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulation walls serve multiple functions: thermal isolation between modules, structural support for battery placement, and guidance for assembly. This multi-functionality reduces the need for additional dedicated cooling components, managing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If contactors are placed close to battery strings to reduce connection length, then the use of energy is reduced, but the reliability deteriorates due to increased heat exposure and potential interference

Engineering Contradiction:
ImproveEnergy loss in connectionsVSAvoidContactor reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The power distribution unit serves as an intermediary structure that houses both contactors and battery terminals in a controlled environment. This intermediary design allows optimized connection length for energy efficiency while providing thermal management and protection to maintain component reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enhances power distribution, improves battery cooling efficiency, and extends the vehicle's operational life by maintaining optimal temperature and charge levels.

Implementation Method 1

at least one evaporator is located between the first PDU housing and the second PDU housing

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

improves battery cooling efficiency, and extends the vehicle's operational life by maintaining optimal temperature

Methodology Applied
Scientific EffectHeat absorption: Heat Exchanger

Data Source

PatentEP4570577A1Electric work vehicle
Publication Date: 2025.06.18 KUBOTA CORP
  • EP4570577A1 patent drawingFigure 1A
  • EP4570577A1 patent drawingFigure 1B
  • EP4570577A1 patent drawingFigure 1C

AI summary

An electric work vehicle (1) includes a power distribution unit (PDU) (130). The PDU includes a first PDU housing to house a positive rail (130-1) and a second PDU housing to house a negative rail (130-2), and the first PDU housing is spaced away from the second PDU housing. The first PDU housing is located on a first side of a centerline (CL) of the electric work vehicle (1) that extends in a front-rear direction of the electric work vehicle, and the second PDU housing is located on a second side of the centerline (CL) of the electric work vehicle opposite to the first side of the centerline (CL) of the electric work vehicle.