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
Dr. Martin März © Fraunhofer IISB
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
Dr. Martin März © Fraunhofer IISB
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
Dr. Martin März © Fraunhofer IISB
4
Smart Battery
… the keys to
minimizing the
complexity of
the high-voltage
electrical system!
Smart Drives
Cost Reduction by System Integration
Smart Battery
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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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)
Cost Reduction by System Integration
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
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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Smart Battery
Multiport DC/DC Converter
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
Dr. Martin März © Fraunhofer IISB
12
Smart Battery
Multiport DC/DC Converter
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
Multiport DC/DC Converter
400 V
120 kW
1) e.g. Li-Ion + SuperCap
DC voltage
unstabilized
unsmoothed
(> Vbat)
SuperC
aps
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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Smart Battery
DC
DC
DC
DC
DC
DC
DC
DC
DC
DC
DC
DC
Multiport DC/DC Converter
400 V
100 kW
Multiport DC/DC Converter
Configuration with maximum flexibility regarding
voltage levels of battery, traction drive, and charging point:
Smart
Battery
System
DC voltage
unstabilized
unsmoothed
(>/< Vbat)
Dr. Martin März © Fraunhofer IISB
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).
Dr. Martin März © Fraunhofer IISB
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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)
Dr. Martin März © Fraunhofer IISB
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
Dr. Martin März © Fraunhofer IISB
18
Smart Battery
How to minimize
■ assembly costs,
■ failure rates, and to
■ maximize modularity
with respect to cell
monitoring and balancing?
Cost Reduction by System Integration
Dr. Martin März © Fraunhofer IISB
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
Dr. Martin März © Fraunhofer IISB
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)
Cost Reduction by System Integration
Data Bus
(bidirectional, contactless, differential)
Dr. Martin März © Fraunhofer IISB
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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
Dr. Martin März © Fraunhofer IISB
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PCIM Europe 2012 – Conference Nuremberg, 10 May 2012
Thank You for Your Attention!