Two-Phase Cooling Circuit for Battery and Converter Thermal Management

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Solution Overview

Problem

Conventional thermal management systems for rechargeable batteries, such as Li-ion batteries, often result in inhomogeneous temperature distribution, which can lead to inefficiencies and reduced battery lifespan, especially in applications like electric vehicles and photovoltaic systems.

Innovation Solution

A closed two-phase cooling system is implemented, where a single cooling circuit with a phase-changing fluid cools both the battery and the converter, maintaining a homogeneous temperature distribution by using the same cooling fluid for both components and regulating fluid flow based on temperature sensors to ensure efficient heat transfer and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional air cooling is used for battery thermal management, then the system is simple and low-cost, but the temperature distribution within the battery becomes inhomogeneous

Engineering Contradiction:
Improvetemperature distribution homogeneityVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent employs phase change material (paraffin wax) that transitions from solid to liquid state to absorb and redistribute heat within the battery housing. This phase transition mechanism enables homogeneous temperature distribution without complex active cooling systems, resolving the contradiction between temperature uniformity and system simplicity

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The cooling fluid acts as an intermediary substance that absorbs heat from battery cells and transfers it to the phase change material. This intermediary mechanism enables effective heat redistribution while maintaining system simplicity, addressing the contradiction between thermal management effectiveness and device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If separate cooling circuits are used for battery and converter, then each component can be optimized independently, but the system complexity and cost increase

Engineering Contradiction:
Improvesystem costVSAvoidindependent optimization capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent merges the battery cooling and converter cooling into a single integrated cooling circuit that circulates the same cooling fluid through both components. This consolidation reduces system complexity and cost while maintaining effective thermal management of both battery and converter, resolving the contradiction between manufacturing ease and independent optimization capability

Inventive Principle:
Principle #5Merging (Combining)

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 approach enhances thermal management, reduces costs, and extends the lifespan of both the battery and converter by maintaining a uniform temperature, thereby improving the overall performance and reliability of battery energy storage systems.

Implementation Method 1

a phase-changing fluid cools both the battery and the converter

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

regulating fluid flow based on temperature sensors to ensure efficient heat transfer and distribution

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP3477764B1Battery energy storage system with two-phase cooling
Publication Date: 2021.03.10 ABB (SCHWEIZ) AG
  • EP3477764B1 patent drawingFigure 1~2
  • EP3477764B1 patent drawingFigure 3~4

AI summary

A battery energy storage system (10) comprises a rechargeable battery (14); a converter (16) for converting a DC current from the rechargeable battery (14) into a current to be supplied to a load (22, 26) and for converting a current from a source (20, 22, 26) into a DC current to be supplied to the rechargeable battery (14); and a closed cooling circuit (18) for cooling the rechargeable battery (14) and the converter (16) with a cooling fluid (32) adapted for performing a phase change, when heated by at least one of the rechargeable battery (14) and the converter (16); wherein the cooling circuit (18) interconnects a cooling component (52) for the rechargeable battery (14) and a cooling component (38) for the converter (16).