Battery Thermal Circuit Isolation for Efficient Self-Heating

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Solution Overview

Problem

In electrical apparatuses like electrified vehicles, there is a need for efficient self-heating of electrical storage devices while effectively utilizing heat generated by drive devices like inverters and motors, as existing systems often lead to heat loss and inefficient heating processes.

Innovation Solution

A thermal management system with a network of flow paths and a switching device that isolates heat exchange between the electrical storage device and the drive device, allowing for efficient self-heating by forming a dedicated heating circuit that prevents heat from escaping to the drive device or radiator, and includes sensors and pumps to optimize heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the electrical storage device is heated using self-heating current, then the temperature of the electrical storage device increases, but heat escapes to the drive device and radiator reducing heating efficiency

Engineering Contradiction:
Improvetemperature of electrical storage deviceVSAvoidheat loss to drive device and radiator
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The thermal management system is divided into multiple independent flow paths (first flow path for electrical storage device, second flow path for drive device, third flow path for radiator, fourth flow path for chiller device). The switching device enables selective connection of these segmented paths, isolating the heating circuit from other thermal components to prevent heat loss while maintaining temperature control capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The switching device dynamically changes the connection state among different flow paths based on thermal management requirements. During self-heating, it connects the first and fourth flow paths while disconnecting the second and third flow paths, creating a dynamic isolation that adapts to the heating phase to prevent heat escape to drive device and radiator.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If heat exchange between electrical storage device and drive device is allowed, then heat utilization efficiency improves, but heating efficiency of electrical storage device decreases

Engineering Contradiction:
Improveheat utilization efficiencyVSAvoidheating efficiency of electrical storage device
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system dynamically switches between two operational modes: during self-heating, the switching device isolates the electrical storage device flow path from the drive device flow path to maximize heating efficiency; after heating, it connects the flow paths to enable heat exchange and heat utilization from the drive device, thus optimizing productivity at different stages.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary heating of the electrical storage device by isolating it from heat exchange with the drive device, ensuring the battery reaches optimal temperature before operation. This preliminary action prevents heat loss during the critical heating phase, and only after heating is complete does the system enable heat exchange for heat recovery.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a simple flow path configuration is used, then device complexity is reduced, but heat isolation and heat exchange control become inefficient

Engineering Contradiction:
Improveflow path configuration complexityVSAvoidheat isolation and heat exchange efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The thermal management system uses a segmented flow path configuration with four distinct paths instead of a single mixed path. This segmentation allows independent control of heat flow to and from the electrical storage device, drive device, radiator, and chiller device, achieving efficient heat isolation and exchange without excessive complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The switching device serves multiple functions: it isolates flow paths during heating, enables heat exchange during operation, and can redirect heat to various destinations (radiator, chiller device). This multi-functional component manages complex thermal requirements without requiring separate dedicated components for each function, balancing complexity and efficiency.

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

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 system enables efficient self-heating of electrical storage devices, enhances traveling performance, and increases charging efficiency by effectively utilizing heat generated by the drive device, while also allowing heat to be used in air conditioning systems when needed.

Implementation Method 1

an electrical storage device configured to exchange heat with the heat medium in the first flow path

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a first flow path configured to allow a heat medium to flow through; an electrical storage device configured to exchange heat with the heat medium in the first flow path

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a drive device configured to exchange heat with the heat medium in the second flow path

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

a second flow path configured to allow a heat medium to flow through; a drive device configured to exchange heat with the heat medium in the second flow path

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

a radiator provided on the third flow path

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 6

a third flow path configured to allow a heat medium to flow through; a radiator provided on the third flow path

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 7

a chiller device provided on the fourth flow path

Methodology Applied
Scientific EffectRefrigeration cycle:

Implementation Method 8

a switching device configured to switch a connection state among the first flow path, the second flow path, the third flow path, and the fourth flow path

Methodology Applied
Scientific EffectValve control: Valve

Implementation Method 9

heat that is generated due to power loss in the internal resistance of the electrical storage device

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4427978A1Thermal management system
Publication Date: 2024.09.11 TOYOTA JIDOSHA KK
  • EP4427978A1 patent drawingFigure 1
  • EP4427978A1 patent drawingFigure 2
  • EP4427978A1 patent drawingFigure 3

AI summary

A thermal management system (1) includes: an electrical storage device (173) configured to exchange heat with a first flow path (170b); a drive device (133) configured to exchange heat with a second flow path (130b); a radiator (122) provided on a third flow path (130a); a chiller device (160) provided on a fourth flow path (170a); and a switching device (180, 190). In the thermal management system (1), during heating control for the electrical storage device (173), the switching device (180, 190) are controlled so that a connection flow path (20) connecting the first flow path (170b) and the fourth flow path (170a) is formed and that the connection flow path (20), the second flow path (130b), and the third flow path (130a) are disconnected from and independent of each other.