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en:dreel:konzept [17.04.2020 23:10]
Bernd.Brincken teardrop |
en:dreel:konzept [19.04.2020 20:02] (current)
Bernd.Brincken [LiFePo] |
| ===== Dreel concept ===== | ===== Dreel concept ===== |
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| The energy required for a vehicle is a sum of the [[wpde>Fahrwiderstand]] (Driving resistances), which have to be overcome: | The energy required for a vehicle is a sum of the [[wpde>Fahrwiderstand]] (Driving resistances), which have to be overcome: |
| - Air resistance or [[wp>Aerodynamic drag]] | - Air resistance or [[wp>Aerodynamic drag]] |
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| === Electro-Economy === | === Electro-Economy === |
| The situation is different for electric vehicles ([[wp>Battery electric vehicle|BEV]]) - the current batteries with the highest energy density, based on [[wp>Lithium]], the element with the greatest [[Wp>normal potential]] in the periodic table, reach about 700 kJ or 200 Wh per kilogram - 1/60 of fossile fuel. This means that the weight and volume of the battery and thus the range become a critical design factor. | The situation is different for electric vehicles ([[wp>Battery electric vehicle|BEV]]) - the current batteries with the highest energy density, based on [[wp>Lithium]], the element with the greatest normalized ionization potentials in the [[wp>periodic table]], reach about 700 kJ or 200 Wh per kilogram - 1/60 of fossile fuel. This means that the weight and volume of the battery and thus the range become a critical design factor. |
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| Another critical factor of the BEV economy is the limited // number of cycles // of the lithium cells, i.e. the number of discharge / charge processes, after which a significant decrease in capacity (typically to 80%) occurs. Cell manufacturers traditionally give this value as '1,000', but the recording of the cycles for laptop batteries already showed the optimism of this number, in real terms often just half is reached. \\ | Another critical factor of the BEV economy is the limited // number of cycles // of the lithium cells, i.e. the number of discharge / charge processes, after which a significant decrease in capacity (typically to 80%) occurs. Cell manufacturers traditionally named '1,000', but the recording of the cycles for laptop batteries already showed the optimism of this number, in real terms often just half was reached. \\ |
| Due to the high charge density, the chemical compounds are broken down faster, in addition there are unavoidable failures ([[https://www.livescience.com/50643-watch-lithium-battery-explode.html|catastrophic failure]]) of individual cells. The 'wear and tear' of a LiIon battery also increases if you exhaust one of the performance parameters: capacity, performance, quick charge and also calendar time. \\ | The reason is that due to the high energy density, the chemical compounds are also broken down faster. In addition [[https://www.livescience.com/50643-watch-lithium-battery-explode.html|catastrophic failures]] of individual cells are unavoidable from time to time. The 'wear and tear' of a LiIon battery also increases if any one of the performance parameters is exhausted: capacity, performance, quick charge and also calendar time. \\ |
| The limited lifespan is therefore an essential cost factor of BEV. This is also explained in the context of the [[: metacell:]] project: [[metacell:ecosystem:Zahlenspiele]]. | The limited battery 'cycle life' is therefore an essential cost factor of current BEV. This is further explained in the [[:metacell:]] project: [[metacell:ecosystem:Zahlenspiele]]. |
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| === Battery strategy === | === Battery strategy === |
| == Tesla == | == Tesla == |
| The US manufacturer Tesla answered these conditions with a simple idea: Let's put so many cells in the car that one battery is sufficient for the typical mileage of the first owner. This resulted in 90 kWh, at roughly 50 ct/Wh until about 2015 - this means $45,000 for the cells alone, without the car around it. A Tesla-S thus inevitably moved into the premium segment and was purposefully marketed there. [[https://www.mdpi.com/2032-6653/9/4/46/htm|Face area and mass]] were high, but this corresponds with the segment. The 90 kWh allow at 20 kWh / 100 km (on US highways) about 450 km (300 miles), which leads to 225,000 km or 140,000 miles even if we only assume 500 cycles - within the typical range of fuel cars. \\ | The US manufacturer Tesla answered these conditions with a simple idea: Let's put so many cells in one car that the battery is sufficient for the typical total mileage of the first owner. This resulted in 90 kWh, which at roughly 50 ct/Wh until about 2015 meant $45,000 for the cells alone, without the car around it. A Tesla-S thus inevitably moved into the premium segment and was purposefully marketed there. [[https://www.mdpi.com/2032-6653/9/4/46/htm|Face area and mass]] were high, but this corresponds with the segment. The 90 kWh allow at 20 kWh / 100 km (on US highways) about 450 km (300 miles), which leads to 225,000 km or 140,000 miles even if we only assume 500 cycles - within the typical range of fuel cars. \\ |
| But at lower retail prices of a BEV, the batteries have to shrink - so does the overall lifespan. What is the price for a middle-class BEV with 100,000 km on the speedometer, whose 50 kWh battery will soon have to be replaced? Close to scrap value. | But at lower retail prices of a BEV, the batteries have to shrink - so does the overall lifespan. \\ |
| | BTW, what would be the sales price for a used middle-class BEV with 100,000 km on the odometer, whose 50 kWh battery will soon have to be replaced? Close to scrap value. |
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| == Dreel == | == Dreel == |
| | {{ :en:dreel:front_dreel_pattern.png?direct&240|}} |
| * Whoever wants to save the climate should suffer. \\ | * Whoever wants to save the climate should suffer. \\ |
| * Comfort, space, performance, design and other traditions are overturned, and instead everything is geared towards lowering air resistance, the essential energy sink for individual transport. | * Comfort, space, performance, design and other traditions are overturned, and instead everything is geared towards lowering air resistance, the essential energy sink for individual transport. |
| * Two people can be transported - one behind the other, because length costs // nothing // when it comes to air resistance. | * Two people can be transported - one behind the other, because length costs // nothing // when it comes to air resistance. |
| * The frontal area becomes significantly smaller when you lie down, your head just high enough that you can see over your feet - see [[wpde>Bobsport]]. \\ target values: end face 0.8 m², cw 0.25 = cw * A __0.20__. | * The frontal area becomes significantly smaller when you lie down, your head just high enough that you can see over your feet - see [[wp>Bobsleigh]]. Target values: Front surface 0.8 m², cw 0.25 = cw * A __0.20__. |
| * Three wheels - two in front, one driven in the back - are ideal, also aerodynamics (teardrop). \\ A two-wheeler is narrower, but has to build the center of gravity higher in order to be acceptable [[wp>Motorbike#cornering | to corner]]. | * Three wheels - two in front, one driven in the back - are ideal for aerodynamics (teardrop shape). \\ A two-wheeler would be narrower, but has to build the center of gravity higher in order to be acceptable [[wp>Motorbike#cornering|to corner]] - this increased front surface as well as aerodynamic turbulences. |
| * Mileage - a Dreel should be able to drive on the highway, because many destinations in Germany can only be reached this way reasonably. 90 km/h are common in the right-hand lane if you do not want to become an obstacle - even on slopes (maximum 8% on motorways). \\ This Dreel's maximum speed is limited to 110 km/h, enough on the flat route to overtake trucks - power requirement increases with the cubic (^ 3) of the speed. | * Performance - a Dreel should be able to drive on the highway, because many destinations in Germany can only be reached this way reasonably. 90 km/h are common in the right-hand lane if you do not want to become an obstacle - even on slopes (maximum 8% on motorways). \\ This Dreel's maximum speed is limited to 110 km/h, enough on the flat route to overtake trucks - power requirement increases with the cubic (^ 3) of the speed. |
| * Engine power - for 80 km / h at cw * A 0.20 modest 2 kW are sufficient, at 90 it is 2.65 kW. | * Engine power - for 80 km / h at cw * A 0.20 modest 2 kW are sufficient, at 90 it is 2.65 kW. |
| * The weight is critical for hills - an additional 5.9 kW is then required, at 300 kg weight and 8% inclination. | * The weight is critical for hills - an additional 5.9 kW is then required, at 300 kg weight and 8% inclination. |
| * 10 kW drive power should therefore be sufficient for these conditions. | * 10 kW engine power should therefore be sufficient for above applications. |
| * Lightweight construction is necessary because of the hills, but with the small space that has to be converted and correspondingly small levers and forces, it can also be easily implemented - target value without passengers: 150 kg | * Lightweight construction is necessary because of the hills, but with the small space that has to be covered and correspondingly small levers and forces, it can also be easily implemented - target value without passengers: 150 kg |
| * Range - 100 km is enough for commuters - at 90 km/h it only takes 2.65 kWh; 4 kWh provide enough buffer and enable a smaller charging stroke (> number of cycles). However, the battery needs to be able to deliver 8 kW for the mountain trip. | * Range - 100 km is enough for commuters - at 90 km/h it only takes 2.65 kWh. 4 kWh battery capacity provide enough buffer and enable a smaller charging stroke, thus a higher cycle count. |
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| == LiFePo == | == LiFePo == |
| Low battery capacity complements each other synergistically with low air resistance: | Low battery capacity complements synergistically with low air resistance: |
| * 4 kWh need e.g. with Samsung 21700 cells only 15 kg and ~ 10 liters, and cost 800 € (net) | * 4 kWh need - for example with Samsung 21700 cells - only 15 kg and ~10 liters, at a cost of € 800 |
| * // Dreel // can thus drive 200 km at 80 km / h, even further with slower driving | * // Dreel // can thus drive 200 km at 80 km / h, or further at lower speeds |
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| This allows a step that is hardly an option for larger BEVs - the switch to [[wp>LiFePO4]] technology. Above all, these batteries offer greater safety - there is no danger of burning electrolyte - and at least twice the number of cycles compared to Li-Cobalt cells. This outweighs the approximately 30% higher price for the user. \\ The disadvantage of the low energy density are double weight and volume, an exclusion criterion for large cars, is not a problem with the // Dreel // because of the low energy requirement in relation to weight and volume: | This allows the switch to [[wp>LiFePO4]] technology which is hardly an option for larger BEVs. These battery technology has better safety because there is no danger of burning electrolyte, and at least twice the number of cycles compared to Li-Cobalt cells. This outweighs the approximately 30% higher price for the user. \\ The disadvantage of the low energy density are double weight and volume. An exclusion criterion for large cars, this is not a problem with the // Dreel // because of the low energy requirement in relation to weight and volume: |
| * 4 kWh LiFePo with brand cells weigh 31 kg and have 22 liters, at a cost of around € 1,000 | * 4 kWh LiFePo with brand cells weigh 31 kg and have 22 liters, at a cost of around € 1,000 |
| * For € 1,600 at 36 kG and 26 l you can get LiFePO cells with a high power density of 20 C. Here you would have enough power for the mountain even with only 500 Wh capacity. \\ Practical middle ground: 2.4 kWh LiFePO at 23 kg and € 1,000. | * For € 1,600 at 36 kG and 26 l you can get LiFePO cells with a high power density of 20 C. Here you would have enough power for the mountain even with only 500 Wh capacity. \\ Practical middle ground: 2.4 kWh LiFePO at 23 kg and € 1,000. |
| * Costs are an additional ~ 8,000 € | * Costs are an additional ~ 8,000 € |
| * This covers EU-approved series of 75 pieces | * This covers EU-approved series of 75 pieces |
| * A [[wpde> EU type approval]] that no longer requires individual approval would be significantly more complex - hardly worthwhile, also because of the ongoing development, which required new approvals for each change. | * A [[wpde>Richtlinie_2007/46/EG|EU model approval]] that allows unlimited production numbers without individual approval would be significantly more complex - hardly worthwhile, also considering the ongoing development, which would require new approvals for each change. |
