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©2016 A123 Systems, LLC. All rights reserved. ©2016 A123 Systems, LLC. All rights reserved.
Angela Duren 11 February 2016
48V Battery System Design for Mild Hybrid Applications
©2016 A123 Systems, LLC. All rights reserved.
Low voltage hybrids are a cost effective solution for higher volume impact on fuel economy requirements
OEM Portfolio Planning; A Balanced Strategy for Fuel Economy
Fuel Economy Requirements
EV
HEV
Micro-hybrid
sales volume
Mild hybrid
48V
©2016 A123 Systems, LLC. All rights reserved.
48V mild hybrids are gaining maturity; should be transparent as start-
stop restarts are improved
• Powertrain efficiencies + Most mature technologies
+ Typically modest gains; except engine downsizing
+ Usually transparent to consumer, unless performance is sacrificed
• Light weighting + Somewhat mature
+ Large impact if implemented across many components
+ Somewhat transparent to consumer except possibly in repair costs
• Electrification + Varying maturity by technology
+ Full range of impact depending on battery/motor size
+ Dramatic variance in levels of consumer transparency
3
Weighing technology maturity and consumer acceptance
Fuel Efficiency Options
©2016 A123 Systems, LLC. All rights reserved. 4
Fuel Economy/ Emissions Impact
Two OEMs have tested A123 battery
in 48V systems coupled with 1.xL
engines, and average fuel economy improvement
projected is 12%
Low Voltage Electrification Steps
©2016 A123 Systems, LLC. All rights reserved.
Attractive system cost per % fuel economy gain
48V Mild Hybrid Incremental Cost
DCT 8-speed (from 6 speed)
F150 700lb reduction
Start-stop
$0
$500
$1,000
$1,500
$2,000
$2,500
0 5 10 15 20 25 30
Incremental system cost ($)
Fuel Economy Improvement (%)
48V mild hybrid
Full hybrid
$55
$83
$87
$167
$35 48V mild hybrids are now
competitive among mainstream fuel saving solutions
$/%
©2016 A123 Systems, LLC. All rights reserved.
2013 2014 2015 2016 2017 2018 2019
A123 Continues to Expand in Low Voltage
12V micro hybrid TBA
48V mild
hybrid
Start of Production
• Low voltage hybridization is a strategic focus for A123 Systems • A123 has now secured 9 low voltage customers globally, some with multiple programs • This experience has enabled insights in market trends and technical requirements
©2016 A123 Systems, LLC. All rights reserved.
48V Battery Requirements are Diverse
• Drivers of 48V systems vary globally and among vehicle types
+ Fuel economy/ emissions improvement (aggressive charge pulses)
+ Electric super charger support/ engine downsizing (aggressive discharge pulses)
+ High power features such as e-A/C and e-Chassis
+ Combinations of the above
• Power requirements from OEMs globally
+ Peak charge power specifications have ranged from 2kW to 21kW
+ Peak discharge power specifications have ranged from 6kW to 18kW
• Various package locations considered affect battery life & dimensional requirements
7
©2016 A123 Systems, LLC. All rights reserved.
Sizing a 48V Battery for Mainstream Markets
• Lithium-ion cells used for HEV applications have power/energy ratios that work well in 48V applications, but most are not sized properly to balance energy, thermal requirements, and cost
• Energy throughput requirements for 48V battery systems range from 100-200Wh
+ Sizing toward the maximum of 180-200Wh yields approximately 4Ah capacity at EOL
• Assuming 50% capacity needed for usable energy window and capacity fade over life, approximately 8Ah BOL capacity is required
• Each lithium-ion chemistry has different requirements that might change this size factor slightly, but this is a good starting point for a chemistry fit comparison
8
©2016 A123 Systems, LLC. All rights reserved.
• Considerations of market solutions + Cost will limit favorability of LTO in this application due to inherent series cell counts
+ NMC and LFP have most potential for mainstream success based on cost
+ Higher impedance of NMC makes active cooling a basic system requirement
• A123 concluded that LFP could be optimized to further reduce impedance and potentially reduce/eliminate the need for active cooling in most 48V applications
9
Considerations for 48V mild HEV battery solutions
A123 Chemistry Solution Portfolio
EV PHEV
EV w/ fast charge HEV Single Battery Micro-Hybrid EV
PHEV
EV w/ fast charge HEV 12V Single Battery (Europe/VDA)
48V Hybrid
High Energy
Dual Battery/ Aux 12V Micro-hybrid
Transportation Battery Solutions
High Power
LFP
LTO NMC (13s)
(14s)
(20s)
©2016 A123 Systems, LLC. All rights reserved. 10
8Ah prismatic cell
Introducing UltraPhosphate™
0%
20%
40%
60%
80%
100%
Cathode Anode Electrolyte Loading
Impedance Change by Attribute
Nanophosphate UltraPhosphate
UltraPhosphate improvements total 65% additional power over previous HEV design
8Ah UltraPhosphate™
[48V]
14Ah Nanophosphate®
[HEV]
HEV Electrode High P/E
Ultra Electrode Extreme P/E
©2016 A123 Systems, LLC. All rights reserved. 11
Custom Battery Solution for 48V Mild Hybrids
0
5
10
15
20
25
0
5
10
15
20
25
LTO NMC A123UltraPhosphate
Pac
k im
ped
ance
[mΩ]
RT
10
s C
har
ge P
ow
er [
kW]
Solution Comparison Scaled to 8Ah
RT 10s Pack Charge Power [kW] Pack impedance [mΩ]
LTO NMC UltraPhosphate
COOLING Not required in
most applications
Usually required due to
higher impedance of
NMC
Not required in most
applications
COST 40-50% more
cells for voltage match
Lowest cell count and
reuse of xEV electrodes
Low cell count and optimal
power density
Typical peak charge power requirement for 48V mild
HEV
UltraPhosphate : very low impedance supports reduced system complexity
without active cooling
©2016 A123 Systems, LLC. All rights reserved.
• Packaging volume, weight, and noise reduction + Reduces battery pack dimensions with elimination of cooling
components
+ No clean air-duct routing
+ No fan noise
+ No cabin pressure concerns
• No thermal integration for OEM
• Reduced vehicle system cost
12
A simpler and more cost effective solution
Benefits of Eliminating Battery Cooling
©2016 A123 Systems, LLC. All rights reserved. 13
C-sample, sourced for production in 2017
48V UltraPhosphate Battery Specification
Specification Unit Performance
Pack Configuration - 14s1p
Chemistry - UltraPhosphate
Capacity Ah 8
Minimum Voltage* V 24
Nominal Voltage V 46
Maximum Voltage* V 54
SOC Range % 30 - 80
10s Discharge @25°C, BOL, 50% SOC kW 15
60s Discharge @25°C, BOL, 50% SOC kW 7.5
10s Charge @ 25°C, BOL, 50% SOC kW 16
60s Charge @ 25°C, BOL, 50% SOC kW 9
Usable Energy BOL @ 25°C Wh > 180
Mass kg 8
Communication Protocol CAN
Length x width x height mm 304 x 108 x 95
©2016 A123 Systems, LLC. All rights reserved. 14
48V Battery Life Projection without Active Cooling
• Cycling in Shanghai hot climate 2.5h/day for 365 days/year
• 1.4 MWh yearly energy throughput
• 23% impedance growth over 10 years
NEDC Drive Cycle Battery Temperatures in Shanghai
©2016 A123 Systems, LLC. All rights reserved. 15
Cold crank gap with lead-acid addressed
UltraPhosphate also supports 12V Starter Battery
0
100
200
300
400
500
600
700
800
900
1000
lead-acid AGM12V 60Ah
A123 Gen212V 60Ah
A123 Gen312V 60Ah
Cold Cranking Amps (7.5V minimum for 10 seconds*)
-18degC
-30degC
A123 has recently achieved parity with lead-acid cold crank performance at -30oC, erasing
the performance barriers to mass market
* Tested to BS EN 50342-1 HE Electrode High E/P
8Ah UltraPhosphate™ 20Ah
UltraPhosphate™
Ultra Electrode Extreme P/E
©2016 A123 Systems, LLC. All rights reserved.
Summary
• System costs of 48V architectures are competitive with other fuel saving technologies, especially with regard to cost per percent improvement and consumer acceptance
• Active battery cooling is an obstacle for mainstream solutions which can be solved with battery cells designed specifically for the 48V application
• A123 Systems’ 48V UltraPhosphate battery is a compact design which can support vehicle architectures designed for fuel economy improvement without active cooling
16
©2016 A123 Systems, LLC. All rights reserved.
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