Thermal Enforcement Matt Reznicek Tim Croyle Scott Nedrow
Dec 19, 2015
Thermal Enforcement
Matt Reznicek
Tim Croyle
Scott Nedrow
Project Requirements
•Maintain Battery Pack at 100°F +-20°
•Provide responsive and accurate measurements of battery temperatures
•Be within budget of project ($3000)
•Have low impact on battery performance
Initial State of ProjectData Acquisition Temperature Measurement
Heating Concepts
1. Resistive Pad Heating
2. Convection Heating (i.e. Diesel Heater)
3. AC Internal Resistance Heating
Resistive Pad Heating
Test 1: 60 Watt Pad on side of battery
Pros:
• Fast
• Easy
Cons:
• Expensive
• Not uniform
• Installation
Pad Heater 60W on Side of Battery
0
20
40
60
80
100
120
0 10 20 30 40 50 60 70 80
Time (min)
Tem
p (
F)
Inside Middle Cell
Inside Outer Cell
Resistive Pad HeatingTest 2: 60 Watt Pad underneath battery
Pad Heater 60W Unerneath Battery
70
75
80
85
90
95
0 5 10 15 20 25 30 35 40 45 50
Time (min)
Tem
p (F
)
Outside on Long Side
Inside Top Temp
Inside Bottom Temp
Pros:
• Fast
• Easy
Cons:
• Expensive
• Not uniform
Resistive Pad HeatingTest 3: 80 Watt Wrap-around Pad
Pros:
• Inexpensive
• Uniform Heating
Cons:
• Bulky
• Slow
• Acts as insulator
• Inefficient
Wrap Around 80W Heater
0
10
20
30
40
50
60
0 10 20 30 40 50 60
Time (min)
Tem
pera
ture
(F)
Inside Outer Cell
Inside Inner Cell
Convection Heating
Cons:• Expensive ($2000+)• Slow• High air Temperatures• Quick cycle time
Pros:•Not Primarily Electric•Uniform Heating
Convection Heating testAmbient air at 195 F
6065707580859095
100105110
0 10 20 30 40 50
Time (min)
Te
mp
(F
)
Outside Temp
Inside Temp
AC Current Heating
Pros:
• Uniform Heating• Low Power• Inexpensive• Very Fast
Cons:
• Circuit Design
AC Heating Test (60A 200mV)
70
72
74
76
78
80
82
84
0 1 2 3 4 5 6
Time (min)
Tem
p
Inside Temp
Outside on Short Side
Outside on Long Side
Comparison
Heating Test Speed Power Draw Uniformity Feasibility Cost Average
Pad Heater on Side 2 3 4 1 4 2.8
Pad Heater Underneath 3 3 4 1 4 3
Pad Heater Wrap 4 4 2 4 2 3.2
Convection Heating 5 1 3 3 3 3
AC Resistance Heating 1 2 1 2 1 1.4
Cooling Fan Test
Observations:• Somewhat Linear cooling• Faster than anticipated• Power draw of ~240 W• Air leaking past box lid
Future Work
• More thorough cooling tests
• Get HEHMMWV mobile
• More AC internal resistance heating tests
• Circuit design for AC heating and cost analysis
• Troubleshoot LabView programming
Questions?