Batteries and Smart Battery Management

Dr. Martin März © Fraunhofer IISB

1

PCIM Europe 2012 – Conference Nuremberg, 10 May 2012

Fraunhofer Institute for Integrated Systems

and Device Technology (FhG-IISB)

Schottkystrasse 10 ● 91058 Erlangen / Germany

Tel. +49 9131/761-310 ● www.iisb.fraunhofer.de

Dr. Martin März

Batteries and Smart Battery Management


2

Smart Battery

Not only a battery

but an intelligent power supply and power management unit!

Safety, protection, and diagnostic functions integrated

(cell monitoring and balancing, SoC (SoH) monitoring, isolation monitoring, deratings, etc.)

Power converters integrated (charger, system voltage sources, etc.)

Effective stand-by and sleep-mode power management integrated

Thermal management integrated


3

Smart Battery

Eigenschaften

Expensive because of numerous shielded

high-voltage cables and connectors

High weight and large occupied space

High effort for safety, reliability and EMC

Eigenschaften

Minimum complexity of HV-harness

No AC-loaded cables,

EMC favourable pure DC-net

Reduced system cost and weight!

Central Power Electronics Smart System Integration

Cost Reduction by System Integration


4

Smart Battery

… the keys to

minimizing the

complexity of

the high-voltage

electrical system!

Smart Drives


Smart Battery


5

Smart Battery

Coolant

Co

nta

ctle

ss s

ign

al tr

an

sm

issio

n

Electrical insulation monitoring

DC

DC

Ibat, Vbat, T

Manual service

disconnect

Main

switch

AC

grid

Mobile AC

socket CAN

isolation

Thermal management and cooling system E-Car controller

Syste

m C

AN

E-D

rive b

us

Smart Battery System

Vehicle contour

High voltage insulation

AC

DC

Aux switch

S-Bat CAN

DC link

precharge

discharge

Cell

heating

Cell

mo

nito

ring a

nd

ba

lan

cin

g

Cell

sta

ck

Thermal insulation

Battery Management Unit (BMU)

Charging

connector

14V Power-Net

DC

DC


6

Smart Battery

Smart

Battery

Ambient: -40°C ... +50°C

+25°C Passenger

compartment

+21°C

AC

AC

DC

AC

AC

DC

Holistic Management of Electrical and Thermal Energy

Reuse of power losses in drives, battery, and power electronics

Thermal preconditioning and battery heating

Thermal encapsulation (insulation)

Smart Battery Energy

Management

-40...+85°C


7

Smart Battery

Benefits

Minimized overall cost, weight, and

installation space

Minimized complexity of HV harness

Favourable EMC characteristics

Integral thermal management

power losses accessible in a combined

form, e.g. for passenger compartment

warming

Stable traction voltage (HV Power net)

improved powertrain efficiency

thinner HV cables (less copper)


14 V Power net

Smart Battery

HV Power net

Public

AC grid

Coolant CAN

Cel

l b

alan

cin

g

Bat

tery

mo

nito

ring

(B

MU

)

Hig

h v

olta

ge

in

sula

tion

Th

erm

al i

nsula

tion

DC

DC

CAN

isolation

DC

DC

AC

DC


8

Smart Battery

+10

+8

+6

+4

+2

0

-2

Ch

an

ge in

Eff

icie

ncy [

%]

0 20 40 60 80 100

Wheel Power [kW]

Powertrain Efficiency

Effect of a HV DC/DC converter for stabilizing the traction voltage

VHV = const.

+7

+6

+5

+4

+3

+2

+1

0

Art

em

is J

am

NE

DC

Art

em

is H

igh

way

DC

DC

Gain in efficiency despite an additional conversion step! Eff

icie

ncy I

mp

rove

me

nt

[%

]

Smart Battery


9

Smart Battery

Half-bridge buck/boost

Voltage VHV may never drop

below VLV !

A short circuit at the HV

terminals cannot be controlled!

Voltage and current-mode with

source or sink characteristic is

possible at both sides

VHV

VLV

Full-bridge buck/boost

Voltage windows may overlap

Short circuit protection and

emergency shut-down is possible

at both terminals

Voltage and current-mode with

source or sink characteristic is

possible at both sides

Basic topologies

V1 V2 V1 V2

VHV

VLV

V1 V2

vo

lta

ge

vo

lta

ge

High-voltage DC/DC Converters for Stabilizing the Traction Voltage


10

Smart Battery

VLV

VHV

A project in cooperation of and

120 kW Buck/Boost Converter

Output power: 120 kW

Switching frequency: 200 kHz

Efficiency: 98,75% (max.)

Power density: 40 kW/liter

Si MOSFET and SiC diodes

Multiport DC/DC Converter

Time base [1 µs/div]

50

40

30

20

10

0

Cu

rre

nt

I L [A

]

500

400

300

200

100

0

Vo

lta

ge

VH

S [V

]

Switching frequency: 200 kHz

Mode: Buck

VHS

IL


11

Smart Battery


Eff

icie

ncy

[%]

100

99

98

97

96

95 0 20 40 60 80 100 120

Output Power [kW]

Buck/Boost

VLV = 333 V

VHV = 400 V

VHV = 450 V

120 kW Buck/Boost Converter

Six buck/boost channels (each 20 kW)

Each channel can be configured as

power source or load,

current or voltage controlled

Fully digital control, CAN interface

Input/output voltage up to 450 V

Water-cooled

Volume: 3 liters


12

Smart Battery


Charge management and balancing of several cell strings or distributed batteries

Support of range extender, hybrid battery1) and battery exchange concepts

DC fast charger functionality for free

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

Smart Battery System


400 V

120 kW

1) e.g. Li-Ion + SuperCap

DC voltage

unstabilized

unsmoothed

(> Vbat)

SuperC

aps


13

Smart Battery

AFE

Active line

frontend

Fast Charger Functionality for Free

DC – the superior approach for quick charging

Minimization of overall system cost

no extra on-board fast charger,

no extra vehicle cost and weight

no expensive quick-charge stations, but

low-cost quick-charge wall sockets without

individual converters

Precise charge management by the Smart Battery itself (advantageous with respect

to liability issues, IP

protection, etc.)

DC bus


14

Smart Battery

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC


400 V

100 kW


Configuration with maximum flexibility regarding

voltage levels of battery, traction drive, and charging point:

Smart

Battery

System

DC voltage

unstabilized

unsmoothed

(>/< Vbat)


15

Smart Battery

Insulating DC/DC Converters for 14/24V on-board Power Supply

2,5 kW Insulating DC/DC-Converter

Input voltage range from 240 V to 400 V

Output voltage range: 9 V to 16 V

Output current: 180 A

Volume: 250 cm³ (10 kW/cm³)

Efficiency up to 95 %

Fully digital control

EMI filter chokes based on polymer

bonded soft magnetics

500 W Insulating DC/DC-Converter

For 14 V supply of electric cars during charging

Optimized for high efficiency up to 96%

Input voltage range from 240 V to 400 V

Volume: 50 cm³

Power density: 10 kW/cm³

Project: Pelikan

Modern Power Converters No limiting factors regarding the Smart Battery Approach.

Neither with respect to size nor with respect to power

dissipation (i.e. the thermal budget of the battery system).


16

Smart Battery

Insulating DC/DC Converters for 14/24V on-board Power Supply

5 kW Insulating DC/DC-Converter

Wide input voltage range: 450 V to 800 V

5 kW continuous output power

24 V to 32 V output voltage

Efficiency up to 94,8 %

Volume: 1 Liter (5 kW/liter)

Fully digital control

Cost effective full silicon power

semiconductor design (no SiC or GaN)


17

Smart Battery

High-voltage

DC/DC Converter

Modular Battery Cell Stack

(incl. cell monitoring and active balancing)

■ LiFePO4 cells (A123)

■ Nominal voltage: 320 V

■ Energy: 2,4 kWh

ICE Starter Battery (14 V)

14V Power-net

DC/DC Converter

(14.4 V, 2.5 kW)

Multi-functional V2G Interface (charger)

BMU (battery management unit)

for a Hybrid Electric Vehicle (HEV)

Smart Battery for Hybrid-TT


18

Smart Battery

How to minimize

■ assembly costs,

■ failure rates, and to

■ maximize modularity

with respect to cell

monitoring and balancing?



19

Smart Battery

System Integrated

New approach

Cell monitoring

and balancing

electronics

CAN-bus Interface Contactless data bus

Balancing resistor

Temperature sensor

Cell heater

Cell Monitoring and Balancing

State-of-the-Art

Cell monitoring

and balancing

electronics


20

Smart Battery

Contactless data transmission via

capacitive coupling

Differential mode ensures high noise immunity

Bidirectional data transmission (for cell

monitoring and control)

Fail safe parallel connection of each cell

to the data bus (no daisy chain)

Battery cells are manufactured with cell

electronics as System-in-Package

(cost reduction by economies of scale)

No failure-prone signal connectors

Simplified battery stack assembly

Cell technology and electronics per-

fectly match (less possible errors)


Data Bus

(bidirectional, contactless, differential)


21

Smart Battery

A System Approach Not Only For Mobile Applications

DC charging

Energy efficient local DC grids

Local power generation

380 V DC Backbone

24...48 V=

20 kV~

Micro-Grid B

1) e.g. a building, small village or city block

Micro-Grid1)

230/400V

AC Grid

Micro-Grid C

En

erg

y B

ac

kb

on

e

AC Consumer

MPP

tracking

Stationary

Smart

Battery

System

Mu

ltipo

rt DC

/DC

Co

nv

erte

r

HV DC Consumer

DC

DC

DC

DC

DC

DC

AC

DC

DC

DC

DC

DC

DC

DC

20 kW

20 kW

20 kW


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PCIM Europe 2012 – Conference Nuremberg, 10 May 2012

Thank You for Your Attention!


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Documents

Batteries and Smart Battery Management