Hybrid Work Machine Independent Battery Cooling System

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Solution Overview

Problem

Conventional hybrid-type working machines face challenges in cooling both the electricity storage device and inverter using a single cooling system, as they operate optimally at different temperature ranges, leading to potential degradation of the lithium-ion battery and reduced working lifetime.

Innovation Solution

A hybrid-type working machine is designed with a separate cooling system for the electricity storage device, utilizing a radiator and cooling pump specifically for the electricity storage device, allowing for independent cooling and optimal temperature settings, thereby improving the operational efficiency and extending the battery's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single cooling system is used to cool both the electricity storage device and inverter, then the device complexity is reduced, but the electricity storage device cannot be cooled to the optimal temperature range

Engineering Contradiction:
Improvecooling system structureVSAvoidcooling temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system is segmented into two independent subsystems: one for the electricity storage device and another for the inverter. This allows each subsystem to be optimized for its specific cooling requirements, with the electricity storage device cooling system capable of maintaining temperatures in the optimal range of -30°C to +45°C, while the inverter cooling system handles its separate thermal management needs.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a single cooling system is used for both components, then the manufacturing cost is reduced, but the working lifetime of the electricity storage device is shortened

Engineering Contradiction:
Improvemanufacturing costVSAvoidworking lifetime
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The cooling system is divided into separate subsystems to prevent thermal interference between the electricity storage device and inverter. This segmentation ensures that the electricity storage device operates within its optimal temperature range, preventing degradation and extending working lifetime, while the inverter is cooled independently according to its own thermal requirements.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If the electricity storage device and inverter are cooled together, then the space occupation is reduced, but the temperature control precision is insufficient

Engineering Contradiction:
Improvespace occupationVSAvoidtemperature control precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The cooling system is segmented into functionally independent subsystems with separate cooling circuits, radiators, and control mechanisms. This enables precise temperature control for the electricity storage device within the range of -30°C to +45°C, while the inverter is cooled separately, ensuring each component maintains optimal operating temperatures despite compact spatial arrangement.

Inventive Principle:
Principle #1Segmentation

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 independent cooling system ensures the electricity storage device operates within an appropriate temperature range, enhancing its performance and extending its working lifetime, while also allowing for a compact cooling system configuration.

Implementation Method 1

a radiator for electricity storage device (42) for cooling the electricity storage device (30)

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

a cooling pump (43) for circulating the coolant, and a cooling line (44) for connection between the radiator (42) and the cooling pump (43)

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 3

The radiator for electricity storage device (42), the cooling pump (43) and the cooling line (44) configuring the cooling system for electricity storage device are provided in the heat exchanger upstream room (28)

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3176334B1Hybrid-type work machine
Publication Date: 2020.01.01 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3176334B1 patent drawingFigure 1
  • EP3176334B1 patent drawingFigure 2
  • EP3176334B1 patent drawingFigure 3

AI summary

There are provided an electric motor (12) that is driven by an engine (8) to generate electric power or assists in a drive of the engine (8) by supply of electric power thereto, a heat exchanger (13) to which cooling air is supplied by a cooling fan (8A), a heat exchanger upstream room (28) that is positioned upstream of the heat exchanger (13) in a flow direction of the cooling air supplied to the heat exchanger (13), and an electricity storage device (30) that stores or discharges electric power. In addition, a radiator (42) for electricity storage device, a cooling pump (43) for electricity storage device and a cooling line (44) for electricity storage device configure a cooling system (41) for electricity storage device that independently cools the electricity storage device (30) aside from the inverter device (34), and the cooling system (41) for electricity storage device is arranged in the heat exchanger upstream room (28).