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Exergy analysis of the thermal behavior of battery cooling processes for HEV and BEV applications

  • Alexander SchydloEmail author
  • Jonas Stöckl
Original Paper
  • 2 Downloads

Abstract

This paper presents the results of a holistic exergy analysis of the cooling circuits for HEV and BEV battery cooling systems. The aim of the performed analysis is to give a proposal for the best possible thermohydraulic solution of the cooling system for battery units. The exergy analysis helps to detect possibilities to improve thermal processes and systems. Exergy is defined as the maximum useful work possible during a reversible process that brings the system into equilibrium with the local ambient parameters. The exergy analysis can help to establish a quality rating of counter-clockwise cyclic processes (e.g. air conditioning, heat pump) with a COP value smaller or even greater than 1. Using evaluation coefficients for the hierarchic exergetic analysis (efficiency, loss coefficient, significance factor and loss component), it is possible to identify the maximum potential of each individual component and also of the total cooling system itself. New optimized concepts for the cooling and heating of battery units are proposed by a numerical analysis of the current cooling circuit for selected operation points. The final effect of the proposed solution is an increase of the vehicle cruising range, an increase of the overall vehicle efficiency and finally—a reduction of the lifecycle costs.

Keywords

Battery cooling Thermal management Hierarchic exergy analysis HEV BEV 

List of symbols

BEV

Battery electric vehicle (–)

CFD

Computational fluid dynamics (–)

COP

Coefficient of performance (–)

DCS

Direct cooling system (–)

\({\dot{E}} \)

Total exergy flow (W)

\(\Delta{\dot{E}} \)

Total exergy loss flow (W)

HEV

Hybrid electric vehicle (–)

ICS

Indirect cooling system (–)

NHV

Noise vibration harshness (–)

PTO

Power take-off (–)

\({\dot{Q}} \)

Heat flux (W)

TXV

Thermal expansion valve (–)

Greek symbols

\(\eta \)

Exergetic efficiency (–)

\(\varepsilon \)

Loss coefficient (–)

\(\kappa \)

Significance factor (–)

λ

Loss component (–)

Subscripts

COMP

Compressor

CON

Condenser

EVAP

Evaporator

IN

Input

0

Reference

P

Product

S

Source

Sub

Subsystem

Sys

System

Notes

References

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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.MAN Truck & Bus MünchenMunichGermany

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