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quote:The tendency these days is to move from chemical batteries towards ultra-capacitors. This is still very new technology, and I imagine still very full of holes, but can deliver massive amounts of peek power
quote:The problem I can assume with compressing gas is how to limit the amount of loss of energy through adiabatic heating as the gas is compressed.
quote:Beyond that, you also have to take into account the massive weight that a pressure vassal may add to the weight of the vehicle.
quote:Originally posted by Atomic-Squote:The tendency these days is to move from chemical batteries towards ultra-capacitors. This is still very new technology, and I imagine still very full of holes, but can deliver massive amounts of peek powerInteresting. I wonder what sorts of quantities of energy these things can store. The only ones I am familiar with are limited to a few volts.
quote:ISE Corporation Case StudyThe depletion of natural resources, air pollution and the rocketing price of gas are all issues that impact the automotive industry. Fortunately, something is being done about it. “Transportation for a clean planet” is the motto of the ISE Corporation, which has been building hybrid and electric vehicles since 1996. A privately held company, ISE Corporation was founded in 1994 by David Mazaika and Michael Simon in San Diego, California. ISE produces Integrated Hybrid Drive Systems, vehicle prototypes and engineering services. Its mission is to become the leading supplier, developer and service provider of electric, hybrid-electric and fuel cell vehicle components, subsystems and drive systems. Thus far, it has successfully integrated dozens of prototype and demonstration vehicles encompassing more than ten different bus, truck and tractor models. The ProblemISE's Hybrid Electric Vehicle (HEV) technology combines the best characteristics of fuel-driven engines, electric motor drives and energy storage components. Their solution has been designed with a combustion engine that functions as the primary power source, and an electric motor with a power storage system that functions as the secondary power source. Designers are able to size the combustion engine for cruising power requirements thanks to the presence of the secondary power source that handles the peak power demands for acceleration. Additionally, regenerative braking energy is captured by the secondary power system and that energy is applied for further acceleration or for the basic energy needs of supplementary electrical systems by using the secondary source.Using only batteries to provide the electrical power storage has drawbacks in the hybrid application. These deficiencies are multiple, and they create many design challenges for automotive engineers. Firstly, batteries have difficulty functioning in cold weather. Secondly, batteries require a sophisticated charge equalization management. Thirdly, batteries have limited cycle life under extreme conditions, which results in high cost replacement throughout the life of the vehicle. A new battery has to be purchased and installed; the old battery has to be removed and disposed. Battery disposal can be problematic unless the manufacturer has a recycling program. All of this adds to the cost of a battery-based system. Perhaps most importantly though, batteries are limited in their ability to capture and provide bursts of high power during short duration events such as acceleration and regenerative braking. This high power limitation reduces the efficiency of the hybrid electric drive system design. The SolutionISE's solution to the above stated problems has been to think beyond batteries; to the reliable technology of ultracapacitors. An ultracapacitor can fulfill many of the functions of batteries in this application, but with dramatically higher reliability and overall performance.Compared to batteries, the key benefits offered by BOOSTCAP ultracapacitors are as follows. Ultracapacitors function well in cold weather, down to –40° Celsius, whereas, without heating, batteries do not operate reliably below 0° degrees Celsius. Ultracapacitors are a safe solution as a pack with equalization is discharged over night. Ultracapacitors have a long life cycle, basically built to last the lifetime of the machine into which they are incorporated and as they are maintenance-free, that ultimately results in cost savings. Ultracapacitors are more efficient than batteries; 84-95% as compared to an average of below 70% for batteries in this application as measured by ISE. Ultracapacitors are very earth-friendly as they are 70% recyclable and do not include any heavy metals which are detrimental to the environment. Ultracapacitors offer up to 10x the power of batteries and in terms of acceleration of a vehicle, this plays an important role. Following is a comparison of a specialized, heated ZEBRA battery solution also used by ISE Corporation as compared to their proprietary Thunderpack II ultracapacitor solution. Code: [Select] ZEBRA Battery Pack Thunderpack II Ultracapacitor PackTypical Usable Energy 18kWh 0.3 kWhCharge and Discharge Current 32kW Over 150 kW Energy Density 87 Wh/kg 4 Wh/kgPower Density 0.16kW/kg 1.5kW/kgExpected Life 2.5-5 year 10-12 yearsSystem Cost 375 $/kW 100 $/kWLife Cycle Cost $1125/kW 100$/KwAs is clearly seen, batteries have high energy capability while the ultracapacitors have high power capability. In an optimal hybrid storage system, both technologies would be combined in a way to maximize the benefits of both.
ZEBRA Battery Pack Thunderpack II Ultracapacitor PackTypical Usable Energy 18kWh 0.3 kWhCharge and Discharge Current 32kW Over 150 kW Energy Density 87 Wh/kg 4 Wh/kgPower Density 0.16kW/kg 1.5kW/kgExpected Life 2.5-5 year 10-12 yearsSystem Cost 375 $/kW 100 $/kWLife Cycle Cost $1125/kW 100$/Kw
quote:Applications Supercapacitors were initially used by the US military to start the engines of tanks and submarines. Most applications nowadays are in the field of hybrid vehicles and handheld electronic devices. NASA has a research project to use supercapacitors in an electric bus called the Hybrid Electric Transit Bus. The energy used to start the engine and accelerate the bus is regenerated from braking. During test runs, a bus loaded with 30 supercapacitors, each of them weighing 32 kg and releasing energy of 50 kJ at 200 V managed to run for four miles. In most hybrid vehicles, 42 V supercapacitors are used. General Motors has developed a pickup truck with a V8 engine that uses the supercapacitor to replace the battery. The efficiency of the engine rose by 14%. The supercapacitor supplies energy to the alternator. Toyota has developed a diesel engine using the same technology and it is claimed to use just 2.7 litres of fuel per 100 km. In rural areas, where there are voltage sags in the power grid, supercapacitors can be used to reduce the effect of fluctuations. The supercapacitor has become available to the public. A commercial supercapacitor can hold 2500 farads, release 300 A of peak current with a peak voltage handling of about 400 V. The life-cycle of this supercapacitor is more than 1,000,000 charge/recharge cycles.
quote:As of spring 2006, EEStor Inc. claims to have a supercapacitor with a barium titanate dielectric nearing production. The company claims a unit with 37 farads capacitance and an operating voltage of 3.5 kV, capable of storing up to 52kWh. The technology is scheduled for third-party verification during the summer of 2006.
quote:quote:The problem I can assume with compressing gas is how to limit the amount of loss of energy through adiabatic heating as the gas is compressed. If the tank is thermally insulated (preferably internally), this would not be a problem.
quote:quote:Beyond that, you also have to take into account the massive weight that a pressure vassal may add to the weight of the vehicle.As compared to what? Lead-acid batteries?