We need an estimate of how long this device will run with different power sources....
Look at batteries of various voltage ratings as options… how long will batteries of these various voltage ratings power a thermoelectric and one compression sensor, one temperature sensor and one Arduino micro-controller? Look up relevant figures for the thermoelectric power consumption, Arduino micro-controller power consumption, compression sensor power consumption and temperature power consumption. Be sure to source where these figures came from i.e. what device, what brand, and corresponding specifications etc. Determine the right formula for estimating power consumption. Knowing the power needs of the compression sensor, temperature sensor, micro-controller, and TEC, you will be able to generate estimates of the amount of battery power we will need and how long those batteries will last. Summarize what you have taught yourself, cite where you found your information, cite where you found your power figures for the components (TEC, sensors, micro-controller) and show comparative values of battery types and sizes versus operation time. Find your batteries on Amazon and remember to include the price. Look at cell phone and laptop batteries as well and include the dimensions and weight of the battery. Everyone in POWER will have this same objective, though the values, and results will be different from each other. The important thing here is to learn how to calculate our power needs and research battery options. Be thorough, go slow and meet all of the requirements to fulfill your objectives. If you have issues don't hesitate to contact me or your other comrades but first, "Be reasonable, just Google It..." -Thanh Ngyuen
Mike Jennings
++++++++++++++++++++++++++++++++++
Power Supply Information Lithium Ion:
It seems the best battery we can get as far as cell voltage is lithium ion. Theres a few new technologies out there but they only seem to better the charging the capacity and have lower cell voltages. Since were looking to have the least bulky power device Lithium ion seems like the best choice. It has an average cell voltage of about 3.6V. This is dependent on the positive and negative electrode materials though. After watching a few videos online it seems far too complex for us to design our own lithium ion batteries (we lack the necessary tools) so our best bet would be to combine various batteries or purchase a battery used for another device which could supply us the power we need. The only difficulty with the lithium ion batteries seems to be charging them. They need to be monitored when charging so as to not overcharge them. Overcharge can have irreversible consequences which will reduce the maximum battery life. There hasn't been much research yet on our chips, TECs and sensors but you could easily combine multiple lithium ion batteries in parallel. This would be much easier to supply the power than trying to create one single battery with the necessary specs to power all of our devices. Due to the recent popularity in Lithium ion batteries, perhaps a small pouch design, such as batteries in cell phones or computers, may be more beneficial to us when trying to create a less bulky device. If a lithium ion battery ever got short circuited on us we could have an explosion on our hands though. It would create an increase in temperature which can be dangerous for us. We would need to create a system to monitor the charge on the lithium ion batteries in order to get the greatest potential from them.
They have some higher voltage lithium ion batteries for sale that we may not have to modify much. They also come with chargers usually so we wouldn't have to worry about overcharging issues. We could possibly use a drill battery which often comes around 18V or a lawnmower battery which comes around 25V. If anyone has old power tools or electric lawnmowers at home we could possibly utilize those as well without spending the money. However the condition of battery life is possibly an issue with going that route.
More to come. Been busy with work all weekend because of Valentines day. Will work with the recommended chips, TECs and sensors once more research is done. --------------------------------------------------------------
Taha Bosaleh
Jerred Jordan
++++++++++++++++++++++++++++++++
So far I have spent many hours not only looking at power supplies but also at one of the building blocks which was the micro-controller that we would be using. I came across not only the Arduino micro-controller but also looked at the PIC.
If we were to go ahead with the lithium battery, an advantage that we would have with using the battery would be that the battery can store up to 25 watt-hours per kilogram. Another benefit about this battery is that you don't need to recondition the battery.Essentially, meaning that you don't have to recharge the battery.Because of the inherent instability of lithium metal, especially during charging, research shifted to a non-metallic lithium battery using lithium ions. Although slightly lower in energy density than lithium metal, lithium-ion is safe, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first lithium-ion battery. Other manufacturers followed suit.
The energy density of lithium-ion is typically twice that of the standard nickel-cadmium. There is potential for higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts allows battery pack designs with only one cell. Most of today's mobile phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion is a low maintenance battery, an advantage that most other chemistries cannot claim. There is no memory and no scheduled cycling is required to prolong the battery's life. In addition, the self-discharge is less than half compared to nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.
Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored to prevent temperature extremes. The maximum charge and discharge current on most packs are is limited to between 1C and 2C. With these precautions in place, the possibility of metallic lithium plating occurring due to overcharge is virtually eliminated.
Aging is a concern with most lithium-ion batteries and many manufacturers remain silent about this issue. Some capacity deterioration is noticeable after one year, whether the battery is in use or not. The battery frequently fails after two or three years. It should be noted that other chemistries also have age-related degenerative effects. This is especially true for nickel-metal-hydride if exposed to high ambient temperatures. At the same time, lithium-ion packs are known to have served for five years in some applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months or so. With such rapid progress, it is difficult to assess how well the revised battery will age.
Storage in a cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, the battery should be partially charged during storage. The manufacturer recommends a 40% charge.
The most economical lithium-ion battery in terms of cost-to-energy ratio is the cylindrical 18650 (18 is the diameter and 650 the length in mm). This cell is used for mobile computing and other applications that do not demand ultra-thin geometry. If a slim pack is required, the prismatic lithium-ion cell is the best choice. These cells come at a higher cost in terms of stored energy. Advantages
High energy density - potential for yet higher capacities.
Does not need prolonged priming when new. One regular charge is all that's needed.
Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
Low Maintenance - no periodic discharge is needed; there is no memory.
Specialty cells can provide very high current to applications such as power tools.
Limitations
Requires protection circuit to maintain voltage and current within safe limits.
Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries. (See last section)
Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
Not fully mature - metals and chemicals are changing on a continuing basis.
The lithium Polymer battery The lithium-polymer differentiates itself from conventional battery systems in the type of electrolyte used. The original design, dating back to the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte. The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring as little as one millimeter (0.039 inches), equipment designers are left to their own imagination in terms of form, shape and size. Unfortunately, the dry lithium-polymer suffers from poor conductivity. The internal resistance is too high and cannot deliver the current bursts needed to power modern communication devices and spin up the hard drives of mobile computing equipment. Heating the cell to 60°C (140°F) and higher increases the conductivity, a requirement that is unsuitable for portable applications. To compromise, some gelled electrolyte has been added. The commercial cells use a separator/ electrolyte membrane prepared from the same traditional porous polyethylene or polypropylene separator filled with a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are very similar in chemistry and materials to their liquid electrolyte counter parts. Lithium-ion-polymer has not caught on as quickly as some analysts had expected. Its superiority to other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved - in fact, the capacity is slightly less than that of the standard lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as batteries for credit cards and other such applications. Advantages
Very low profile - batteries resembling the profile of a credit card are feasible.
Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
Limitations
Lower energy density and decreased cycle count compared to lithium-ion.
Expensive to manufacture.
No standard sizes. Most cells are produced for high volume consumer markets.
Higher cost-to-energy ratio than lithium-ion
Restrictions on lithium content for air travel
Resources- Introduction to Background of Lithium-ion Battery
Research Group of Lithium-ion Battery Material of USTC
Look at batteries of various voltage ratings as options… how long will batteries of these various voltage ratings power a thermoelectric and one compression sensor, one temperature sensor and one Arduino micro-controller? Look up relevant figures for the thermoelectric power consumption, Arduino micro-controller power consumption, compression sensor power consumption and temperature power consumption. Be sure to source where these figures came from i.e. what device, what brand, and corresponding specifications etc. Determine the right formula for estimating power consumption. Knowing the power needs of the compression sensor, temperature sensor, micro-controller, and TEC, you will be able to generate estimates of the amount of battery power we will need and how long those batteries will last. Summarize what you have taught yourself, cite where you found your information, cite where you found your power figures for the components (TEC, sensors, micro-controller) and show comparative values of battery types and sizes versus operation time. Find your batteries on Amazon and remember to include the price. Look at cell phone and laptop batteries as well and include the dimensions and weight of the battery. Everyone in POWER will have this same objective, though the values, and results will be different from each other. The important thing here is to learn how to calculate our power needs and research battery options. Be thorough, go slow and meet all of the requirements to fulfill your objectives. If you have issues don't hesitate to contact me or your other comrades but first, "Be reasonable, just Google It..." -Thanh Ngyuen
Mike Jennings
++++++++++++++++++++++++++++++++++
Power Supply Information
Lithium Ion:
It seems the best battery we can get as far as cell voltage is lithium ion. Theres a few new technologies out there but they only seem to better the charging the capacity and have lower cell voltages. Since were looking to have the least bulky power device Lithium ion seems like the best choice. It has an average cell voltage of about 3.6V. This is dependent on the positive and negative electrode materials though. After watching a few videos online it seems far too complex for us to design our own lithium ion batteries (we lack the necessary tools) so our best bet would be to combine various batteries or purchase a battery used for another device which could supply us the power we need. The only difficulty with the lithium ion batteries seems to be charging them. They need to be monitored when charging so as to not overcharge them. Overcharge can have irreversible consequences which will reduce the maximum battery life. There hasn't been much research yet on our chips, TECs and sensors but you could easily combine multiple lithium ion batteries in parallel. This would be much easier to supply the power than trying to create one single battery with the necessary specs to power all of our devices. Due to the recent popularity in Lithium ion batteries, perhaps a small pouch design, such as batteries in cell phones or computers, may be more beneficial to us when trying to create a less bulky device. If a lithium ion battery ever got short circuited on us we could have an explosion on our hands though. It would create an increase in temperature which can be dangerous for us. We would need to create a system to monitor the charge on the lithium ion batteries in order to get the greatest potential from them.
Resources:
http://en.wikipedia.org/wiki/Lithium-ion_battery
http://www.greenbatteries.com/libafa.html
Buying Options:
They have some higher voltage lithium ion batteries for sale that we may not have to modify much. They also come with chargers usually so we wouldn't have to worry about overcharging issues. We could possibly use a drill battery which often comes around 18V or a lawnmower battery which comes around 25V. If anyone has old power tools or electric lawnmowers at home we could possibly utilize those as well without spending the money. However the condition of battery life is possibly an issue with going that route.
Lawnmower battery:
http://www.amazon.com/Gardena-25-Volt-Lithium-Ion-Battery-Cordless/dp/B001RCUGAO/ref=sr_1_155?s=hi&ie=UTF8&qid=1297651204&sr=1-155
This here is basically an encyclopedia of lithium ion batteries to purchase and modify for our power source. None of them take up much room. I'm assuming they could all easily be attached to someones waist without much hinderance:
http://www.onlybatteries.com/?cat1=27
More to come. Been busy with work all weekend because of Valentines day. Will work with the recommended chips, TECs and sensors once more research is done.
--------------------------------------------------------------
Taha Bosaleh
Jerred Jordan
++++++++++++++++++++++++++++++++
So far I have spent many hours not only looking at power supplies but also at one of the building blocks which was the micro-controller that we would be using. I came across not only the Arduino micro-controller but also looked at the PIC.
This is the Arduino that I took a look at http://arduino.cc/en/Main/ArduinoBoardNano - jus basic specifications
http://store.gravitech.us/arna30wiatp.html - page that looks at the price and specifications
This is the pic: http://www.best-microcontroller-projects.com/pic-microcontroller.html
Also I took a look at this specifically: http://www.best-microcontroller-projects.com/temperature-recorder.html
http://forum.allaboutcircuits.com/showthread.php?t=24317 – This is where a lot of reading was done.
When it comes to prices the PIC is a better deal however from what I read the Arduino is easy for beginner programmers. Also I believe that the project with the temperature recorder would be a nice place to start from
Next I looked at Thermo electric Devices, after a while of looking I stopped at Marlow industries they have not only a lot of choices their but some other things as wellhttp://www.marlow.com/thermoelectric-modules/
Below is one of the Thermoelectric devices I thought would be best to use then again there are a lot and I would like to discuss it with the class as well.
http://www.marlow.com/thermoelectric-modules/single-stage/xlt2393-00l.html
I also liked this http://www.marlow.com/resources/university/rules-of-thumb-for-tecs.html
Lastly Marlow does partnerships with universities check it out : http://www.marlow.com/resources/university/partnering-universities.html
Professor Mellodge this is something I think you and I should look into further,
--------------------------------------------------------------
Evan Thomson
+++++++++++++++++++++++++++++++++++
If we were to go ahead with the lithium battery, an advantage that we would have with using the battery would be that the battery can store up to 25 watt-hours per kilogram. Another benefit about this battery is that you don't need to recondition the battery.Essentially, meaning that you don't have to recharge the battery.Because of the inherent instability of lithium metal, especially during charging, research shifted to a non-metallic lithium battery using lithium ions. Although slightly lower in energy density than lithium metal, lithium-ion is safe, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first lithium-ion battery. Other manufacturers followed suit.
The energy density of lithium-ion is typically twice that of the standard nickel-cadmium. There is potential for higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts allows battery pack designs with only one cell. Most of today's mobile phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion is a low maintenance battery, an advantage that most other chemistries cannot claim. There is no memory and no scheduled cycling is required to prolong the battery's life. In addition, the self-discharge is less than half compared to nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.
Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored to prevent temperature extremes. The maximum charge and discharge current on most packs are is limited to between 1C and 2C. With these precautions in place, the possibility of metallic lithium plating occurring due to overcharge is virtually eliminated.
Aging is a concern with most lithium-ion batteries and many manufacturers remain silent about this issue. Some capacity deterioration is noticeable after one year, whether the battery is in use or not. The battery frequently fails after two or three years. It should be noted that other chemistries also have age-related degenerative effects. This is especially true for nickel-metal-hydride if exposed to high ambient temperatures. At the same time, lithium-ion packs are known to have served for five years in some applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months or so. With such rapid progress, it is difficult to assess how well the revised battery will age.
Storage in a cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, the battery should be partially charged during storage. The manufacturer recommends a 40% charge.
The most economical lithium-ion battery in terms of cost-to-energy ratio is the cylindrical 18650 (18 is the diameter and 650 the length in mm). This cell is used for mobile computing and other applications that do not demand ultra-thin geometry. If a slim pack is required, the prismatic lithium-ion cell is the best choice. These cells come at a higher cost in terms of stored energy.
Advantages
- High energy density - potential for yet higher capacities.
- Does not need prolonged priming when new. One regular charge is all that's needed.
- Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
- Low Maintenance - no periodic discharge is needed; there is no memory.
- Specialty cells can provide very high current to applications such as power tools.
Limitations- Requires protection circuit to maintain voltage and current within safe limits.
- Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
- Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries. (See last section)
- Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
- Not fully mature - metals and chemicals are changing on a continuing basis.
The lithium Polymer batteryThe lithium-polymer differentiates itself from conventional battery systems in the type of electrolyte used. The original design, dating back to the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring as little as one millimeter (0.039 inches), equipment designers are left to their own imagination in terms of form, shape and size.
Unfortunately, the dry lithium-polymer suffers from poor conductivity. The internal resistance is too high and cannot deliver the current bursts needed to power modern communication devices and spin up the hard drives of mobile computing equipment. Heating the cell to 60°C (140°F) and higher increases the conductivity, a requirement that is unsuitable for portable applications.
To compromise, some gelled electrolyte has been added. The commercial cells use a separator/ electrolyte membrane prepared from the same traditional porous polyethylene or polypropylene separator filled with a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are very similar in chemistry and materials to their liquid electrolyte counter parts.
Lithium-ion-polymer has not caught on as quickly as some analysts had expected. Its superiority to other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved - in fact, the capacity is slightly less than that of the standard lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as batteries for credit cards and other such applications.
Advantages
- Very low profile - batteries resembling the profile of a credit card are feasible.
- Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
- Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
- Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
Limitations- Lower energy density and decreased cycle count compared to lithium-ion.
- Expensive to manufacture.
- No standard sizes. Most cells are produced for high volume consumer markets.
- Higher cost-to-energy ratio than lithium-ion
Restrictions on lithium content for air travelResources-
Introduction to Background of Lithium-ion Battery
http://libattery.ustc.edu.cn/english/introduction%202.htm