Vehicle Battery Cooling Circuit Using Pump-Driven Refrigerant Flow

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Solution Overview

Problem

Existing cooling devices for vehicle batteries, particularly in rail vehicles, are energy-intensive and require additional components, increasing manufacturing costs, weight, and space, with existing solutions not suitable for high-pressure refrigerant CO2 and inefficient at high ambient temperatures.

Innovation Solution

A cooling device with a refrigerant circuit and coolant circuit coupled via a heat exchanger, featuring a condenser, refrigerant pump, expansion valve, evaporator, and compressor, with a bypass system allowing the compressor to be switched off at low temperatures, using a sensor to control refrigerant flow and optimize cooling capacity, and utilizing common refrigerants like R134a.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a refrigeration system based on compression refrigeration principle is used to cool battery cells below ambient temperatures, then cooling performance is improved, but energy consumption increases significantly

Engineering Contradiction:
Improvebattery cell temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system changes the operating parameters of the refrigeration cycle by using a refrigerant pump to circulate refrigerant instead of relying solely on compressor-driven flow. This allows the system to achieve effective cooling with lower energy input by optimizing the refrigerant circulation parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the traditional compressor-based refrigerant circulation with a pump-based system. This mechanical substitution reduces energy consumption while maintaining the ability to cool battery cells below ambient temperatures

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If additional cooler components are added to enable cooling without refrigeration unit operation, then cooling capability is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvebattery cooling capabilityVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The refrigerant pump serves multiple functions: it circulates refrigerant during both refrigeration mode and ambient cooling mode, replacing the need for separate cooling components. This multi-functionality reduces device complexity while maintaining cooling capability across different operating conditions

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

Solution Approach 2:

The invention merges the refrigerant circulation function with the cooling function by using the same pump and heat exchanger components for both refrigeration-based cooling and ambient temperature cooling, eliminating the need for additional separate cooler components

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If CO2 refrigerant is used in high-pressure applications, then cooling efficiency is improved, but pressure resistance requirements and system tightness become technically impossible or require great effort

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsystem tightness and pressure resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system changes the pressure parameters by using a refrigerant pump instead of a high-pressure compressor, operating at lower pressures while maintaining cooling efficiency. This parameter change eliminates the need for extreme pressure resistance and tightness requirements

Inventive Principle:
Principle #35Parameter changes

4Temperature

If radiator is constantly circulated by air to enable cooling at low temperatures, then cooling performance is improved, but space requirements and manufacturing costs increase

Engineering Contradiction:
Improvebattery cooling performanceVSAvoidspace requirements
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The invention replaces air-based cooling with a closed-loop liquid refrigerant circulation system using a pump. This substitution eliminates the need for large radiators and constant air circulation, reducing space requirements while maintaining cooling performance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables energy-efficient cooling of vehicle batteries with minimal equipment, reducing energy consumption and space requirements, while maintaining optimal cooling performance across varying ambient conditions.

Implementation Method 1

a refrigerant circuit and a coolant circuit, which are coupled via a heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a condenser, a refrigerant pump arranged downstream thereof

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

an evaporator arranged even further downstream, which is designed as a heat exchanger with the coolant circuit

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

a refrigerant pump arranged downstream thereof

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP4049888B1Cooling device for a car battery
Publication Date: 2024.12.18 SIEMENS MOBILITY GMBH
  • EP4049888B1 patent drawingFigure 1~2
  • EP4049888B1 patent drawingFigure 3~4
  • EP4049888B1 patent drawingFigure 5

AI summary

The cooling device according to the invention comprises a refrigerant circuit and a coolant circuit coupled to it. The refrigerant flow can be controlled by means of a sensor, which in turn controls a valve or a refrigerant pump. At low ambient temperatures, the compressor is switched off, thus enabling efficient cooling, particularly for a vehicle battery.