Preliminary Design Review 1 Team Members: Chris Douglas – Project Manager David Hooker – Lead...
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Team AutoVolt Preliminary Design Review 1 Team Members: Chris Douglas – Project Manager David Hooker – Lead Research, Webmaster James Randall – Liaison, Budget Manager Sponsors: Naval Surface Warfare Center: Acoustic Research Detachment, Bayview ID Advisor: Dr. Gregory Donohoe, University of Idaho Mentor: Dr. Herbert Hess, University of Idaho
Preliminary Design Review 1 Team Members: Chris Douglas – Project Manager David Hooker – Lead Research, Webmaster James Randall – Liaison, Budget Manager
Preliminary Design Review 1 Team Members: Chris Douglas Project
Manager David Hooker Lead Research, Webmaster James Randall
Liaison, Budget Manager Sponsors: Naval Surface Warfare Center:
Acoustic Research Detachment, Bayview ID Advisor: Dr. Gregory
Donohoe, University of Idaho Mentor: Dr. Herbert Hess, University
of Idaho
Slide 2
Problem Statement, Specifications, Deliverables Current System,
Situation Design Concepts Trade Study Equipment Return on
Investment Timeline/Future Work Challenges 2
Slide 3
The Large Scale Vehicle 2 (LSV2) is an autonomous electric
submarine used to study acoustic properties of propulsion systems.
The Acoustic Research Detachment 3 (ARD) has requested improvement
of capacity retention over the course of the propulsion batteries
life cycle.
Slide 4
Document current charging configuration with scheme advantages
and disadvantages Research of potential changes to system to extend
capacity retention Develop a cost-benefit analysis of implementing
a new charging scheme Produce computer simulations of current and
alternate configurations Construct lab scaled model of current and
alternate schemes 4
Slide 5
Current System Report Trade Study Selected Choices Summary
Overview of Rejected Proposals Cost-Benefit Report Lab Test Report
Proof of Safety Report Computer Simulation 5
Slide 6
6 1. CC(45A/string) until 2.35V/cell 2. CV until 6.25A/string
3. CC for 3 hours with 2.50V/cell voltage limit2.50V/cell voltage
limit Main Charge Overcharge 1680 2V batteries divided into 4
parallel strings Approximately 15min checks Batteries
decommissioned @ 4 years(approx. 80% capacity)
Slide 7
Human charge control can lead to undercharge or overcharge Both
OC and UC can lead to battery life degradation Charging
infrastructure maxed Chargers working at max current wiring from
chargers to sub at max current Power grid already overloaded Aux.
battery charge ~ 12 hours Two types of chargers readily available
7
Slide 8
Extend useful life of batteries Reduce expenses over long term
Reduce submarine downtime over long term resulting in higher return
for taxpayer dollars Reduce the capacity loss of batteries over
current service life Maintain underway duration over service life
8
Slide 9
Automate System Free up technicians for other purposes Reduce
risk of error of human control Improve Oxygen recombination
efficiency(ORE) Reduce outgassing Decrease energy waste 9
Slide 10
Zero Delta Voltage (ZDV) Concept Max current charges until 70%
return of charge Constant Current (C/5) until ZDV is reached ZDV is
defined as a limit in change in voltage between two readings A
reading is defined as 30 second averages of voltage readings 10
Voltage
Slide 11
Pros Accurately detects end of charge cycle Reduces human error
during charge cycle Reduces possibility of detrimental
undercharge/overcharge Possible 100% increase of battery life Cons
Will need to be tested on multiple battery system Variable voltage
termination limit over life of batteries 11
Slide 12
Current Interrupt (CI) Concept Used after primary charge has
completed (overcharge) Charge algorithm consists of a pulsed
current CI is employed until 10% overcharge has been achieved
12...
Slide 13
Pros Allows cooling period for batteries preventing excessive
thermal degradation Allows for chemical reactions to stabilize
during the off period leading to higher ORE Can be used
independently of main charge method Cons Unknown change in charge
time Setup of system may be complex Normally employed after a fast
charge algorithm has delivered 100% of depleted charge 13
Slide 14
Fast Charging Start with large current pulses (up to 4C)
Monitor voltage and step down current each time voltage limit is
reached 14
Slide 15
15 Pros Is an extremely fast charge method Increases capacity
retention throughout life Cons Requires enormous amounts of current
(up to 600A) Generates large amounts of heat
Slide 16
16 ItemMethodWeight CI/CVZDVCIFC Cat Caps Software
Complexity0.270.240.2 0.33% Power Requirements0.450.540.30.10.66%
Shore Power Considerations1.5 0 15% Rewiring of both Barge and
Vessel0.20.180.20 2% Difficulty of
Implementation0.450.350.40.20.45% Charge available for
Underway1.21.61.821.620% Expected EOL Capacity0.30.60.910.810%
External Interfacing of Controls?????8% Reduction in Charge
time?????1% Cost of Implementation?????5% Long term Costs
reduction?????25% Higher score is better4.375.015.23.45.4100%
39%
Slide 17
CI and ZDV require testing Charge module capabilities unknown
Testing is required to determine charge time Long term effects to
be determined 17
Slide 18
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Slide 19
Software capable of accurately simulating cycle life has yet to
be discovered State of health simulation is unfeasible at this time
due to: Varying discharge rates during each test run Varying
internal characteristics and chemical composition over battery life
Varying and unknown cell temperatures for charge and discharge
cycles Development contingent upon lab data 19
Slide 20
20 ItemDescriptionQty Base Cost Total BatteriesNew LSV2 battery
(2025 Lead) 6 $340.00 $2,040.00 Charge/Discharge System Arbin
BT2000 / AeroVironment ABC- 150 or ABC-5 1 PENDING Catalyst
CapsOxygen Recombination Catalyst 3 $35.00 $105.00 Total
PENDING
Slide 21
CONTINUED USE OF SYSTEM BENEFITS OF NEW SYSTEM $593,000/4 years
for Main battery replacement Labor costs of replacement process
Extending battery service life by at least 50% yields savings of
$50,000/year (not including man hours) Length of underways can be
maintained over longer period of time yielding more data collected
per run 21
Slide 22
State of health simulations non-existent Time constraints for
cycle life testing Managing multiple test cases Access to charger
control module Access to /Purchase of testing equipment 22
Slide 23
Schedule with design of charge/discharge system Alternative
budget to be determined 23