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Electric Car
Electric car charging at National Air and Space Museum, 12 December 2016.
Classification	Vehicle
Industry	Various
Application	Transportation
Fuel source	electric, solar
Powered	Yes
Self-propelled	Yes
Wheels	3–4
Axles	2
Inventor	Robert Anderson

== Electric car charging methods ==

The battery back of electric car

The electronic car is the mainstream of future tool of transportation; many governments and car industry has set a goal to abandon the gasoline car within decades such as Britain, China, France, Germany, India, Ireland, Israel, the Netherlands, Norway, Costa Rica, Denmark, and Spain. The range is still a huge potential issue for electrical vehicle.For now the longest range for the electronic car which be recorded is 606.2 miles achieved by Tesla model 3 in an extreme condition without air condition and held in a constant speed. In a normal situation, the electronic battery power could be held for 500km, equivalent to two or three days city commuting or even one day in winter. Therefore the long road trip is nearly impossible for the electronic car. The rapid charging will be important to electronic since the size of a car is fixed and the developing of batteries power is still on the researching, thus the charging station will provide as an intermediate to expand the range of the electric car.

The principle of rapid charging

the basic process of battery discharging and charging that is when charging, Li‐ions from the positive electrode, pass through a separator/electrolyte, transfer via a solid electrolyte interface (SEI), and intercalate into the negative electrode. The potential negative impact for rapid charging is the battery aging will be accelerating by the unstable SEI produced by multi-times charging and discharging. While the new pulse charging has a significant change in the stability of SEI, since the unnecessary chemical reaction has been reduced by the new charging method and SEI is grown via a reduction reaction. Thus the battery lifecycle and efficiency had a significant improvement with the traditional charging method.

The oxygen will be produced during charging, and in the closed environment the oxygen produced by positive electron can pass through the barrier and be absorbed by the negative electron, and the whole chemical reaction forms a cyclic reaction form. Since the battery is closed so the internal pressure is limited. Therefore if the charging voltage is too high the absorption rate of the negative electron will no longer at the same rate with the production of oxygen. After long time the battery will be damaged. Even more, the over pressure of battery may causes the internal temperature of battery get rise to expansion and explosion.

The comparison of charging time between different charging algorithms

The different algorithms are varies in charging efficiency, charging time, battery life cycles and costs. However the researchers still cannot define which is the most appropriate one for the application, as so many algorithms have been developed. Each one which their own advantages and disadvantages. For instance, making the comparison between the constant current-constant voltage charging method and the multistage current charging algorithm. The former has a longer charging time compared with the latter, while cost of research on latter is way more than the former.

Constant current

The constant charging method is adjusts the output voltage of charging devices or the resistance in series with the battery to keep the current constant.It is using the constant current value form the beginning to the end of charging. As nickel-cadmium batteries are easy to polarize during conventional charging, both conventional constant voltage and constant current charging will make the electrolyte continuously produce hydrogen-oxygen gas. Under the action of internal high pressure, the oxygen penetrates to the negative electrode and interacts with cadmium plate to generate CdO, resulting in the decrease of effective capacity of the electrode plate.As the acceptable current capacity of the battery decreases gradually with the progress of the charging process, it will lead to overcharging of the battery in the later charging period. Constant current in the late charge is mostly used for electrolysis of water to produce gas, making the battery internal pressure rise, do not control easy to make the battery dry due to water loss. Eventually, it will also lead to a sharp drop in battery capacity.

Constant voltage

It is a widely used charging method that the voltage between the battery poles is maintained at a constant value. The starting battery is also in a similar condition of constant voltage charging when the vehicle is running. Its advantage are with the battery charged state changes, automatically adjust the charging current, if the specified voltage constant value is appropriate, can ensure that the battery is fully charged, but also to minimize gas and water loss.

Variant of Constant Current/Constant Voltage charging algorithms

The variant of CC/CV charging algorithms is the further development of the constant CC/CV. The boost charger（BC) is one of it. In stead of using the constant voltage and current in the entire charging period, the BC is to boost the charging efficiency through maximize the voltage in the first period, and the charging capacity could reach 30% of its nominal capacity approximately. After this period, the charging algorithm is then switched to the standard CC/CV. Due to the initial higher charging voltage, the BC-CC/CV can charge the battery faster than the CC/CV, but it is required to fully discharge the battery before charging which requires the discharge circuit. While, this algorithms will increase the number of components and cost. As the charger is needed to be variant in the voltage, all component need to be afford the voltage, contemporary.The necessity of discharge before charging is important as this will influence the efficiency charging algorithm and the lifecycle of batteries. According to the statistical result of survey on The effect of initial higher charging voltage on the battery life has been investigated. It shows that there is no obvious degradation within 500 testing cycles.

Multistage current charging algorithm

This method is mainly divided the entire charging period into several charging stages that were proposed to use the optimal charging current to fit it. In order to, maximize the charging efficient. By determined the optimal charging current for each stage, we can use the fuzzy controller to determining the charging current by the change in temperature. To sum up, this algorithm is based on the micro-controller or a computer. The charging speed is faster and charging efficiency is higher than those of the CC/CV.

Non-contract charging(wireless charging)

The wireless charging technology

Wireless technology is a kind of method to transfer energy in air between the charger and battery, by the magnetic resonance of the coil and capacitor. In order to achieved a high efficient energy transformation.

Applications

The non-contract charging could be used on parking space, garages and even on buses that run in closed routes. on the current technology the application could only be apply on the relative fixed area. Finally, the technology could be applied on multiple occasions like highways, the G-series high-speed train and so on.

Advantages

As the non-contract charger could keeping charging the vehicle so it allows EVs have a smaller battery, it is more economy, safer and more sustainable developed. Since the battery is major cost of the EV, therefore not only the cost of EV is lower, but also the demand is boost for the lower market price.

Disadvantages

The cost side of developing the Non-contract charging system involves huge financial support. For a lager proportion of the new resources car manufactories is using the traditional charging methods to lowering the cost. It could be a competitive priority in the long run. Thus, for the giants in the industry may decide to do so.

The safety side is also important, as the Non-contract charging system is based on the electromagnetic field. In some circumstance exposes in the field may be harmful, the electronic devises and animals may be influenced too.

The efficiency is also being a serious challenge for researchers.Since making the comparison between the traditional charger and Non-contract one, the latter will loss 30% within the charging.

The quick battery swapping charging method

The battery could be fully charged in two or ten minutes, by special of technical personnel, through the use of automatic or semi-automatic technology replace the empty battery to a full powered one. So as to achieve comparable fuel refueling speed like the traditional gasoline vehicle. And the NIO is the leading company in the industry, the world's first battery swapping technology in its kind.

The service capacity

The power is changed 3 minutes at a time, and the battery that feeds still needs to be charged quickly inside the station, because this cannot change power ceaselessly without limit comes out. The design service capacity of NIO electrical changing station is 72 vehicles/day, which is enough to support most vehicle situations.

If the load of local electrical changing station is too high, NIO will use big data analysis to add another electrical changing station in the most convenient geographical location for users.

The biggest advantage

In the swapping mode, the batteries from each individual car is on the circulation. Gathering on the battery station, and for exchange a new one. This will increasing the manufacturer's ability for the Battery monitoring/maintenance and battery iteration. Since battery is a major problem for electric car, the car's life expectancy is 10-20 years，while the electric car is much shorter may be 10 years at most at the current technology This is due to the decline in the battery life. Nevertheless, in this method, the battery power decline will no longer be the excuse for the short lifecycle.

The costs

Even the cost of the electrical changing station has not disclosed. In terms of inference, For one thing, the current output of electrical changing station is limited, the research&development cost is uneven, so the monomer cost could be very high. Second, although the electrical changing station does not need civil construction, the human/capital cost of communication with high-speed service station/residential building material management/power department is very high. Third, do not load the car battery pack, because there is no subsidy, monomer cost is very high; Fourthly, at present, the automatic driving technology of ES8 is still not open, the electrical changing station must have a duty commissioner of 24h, and the labor cost is very high.

The application

If the electrical changing station mode is successful in the future, there is one significant problem how can the car industry ensure each individual is using the same brand of car, the battery size between different brands cannot be unified. Therefore how many changing station is needed for serve the hundreds and thousands of brands of electrical car in the city.

Ideally, the mode is fitted for the public transports, like Cabs, commuting buses, and operating vehicle.Those cars are basic running in the city. Likewise choosing the same brand or model of pure electric cars will facilitate the operating，management and future maintenance of enterprises.

Solar panel charging

Solar panel charging

The Sion is the first real massive production electric car powered by the solar energy.

The main unique characteristic of the car is its appearance, the whole car is covered by the solar cells on the car surface, almost everywhere in which could be visually observed, like the roof, sides, Rear and the hood of the vehicle

By seamlessly integrating solar cells into the entire body, Sion can easily charge its batteries from the sun. Thus, under ideal conditions, using pure solar energy could achieve an additional range of up to 34km per day, which would mean complete self-sufficiency over short distances. For solar integration, Sion USES mono-crystalline silicon cells that generate energy even on cloudy or cool days. At peak performance, the integrated battery can generate up to 1.2 kilowatts of power. It also offers plug-in charging at home or in the workplace.

While the car will be open the delivery until the 2021.

The advantages

The structure of electrical vehicle vehicle is light and small. Light model can greatly reduce energy consumption, reduce cost; small body, the body is unnecessary to be too large, as the less demand of the battery, the small body could improve the traffic condition, especially for some aged city, is hard to increase the traffic flow by remove the protected building.

No pollution. Because it does not use fuel, it will not emit harmful gases that pollute the atmosphere.

No noise. Without an internal combustion engine, you wouldn't hear the roar of fuel-powered cars.

The limited petroleum resources can be saved by replacing oil with light and electricity. During the day, solar cells convert light energy into electricity and store it automatically in power cells. At night or on rainy days, the vehicle can be charged by using the household alternating current (220V) to ensure the normal operation of the vehicle.

Energy saving. The solar electric vehicle of the invention consumes less energy and can be driven by using only 3-4 square meters of solar cell modules. In the process of energy conversion, fuel vehicles should follow the Carnot cycle to do work, and their thermal efficiency is relatively low, about 12%-15%. Only 1/3 of the energy is used to push the vehicle forward, and the rest 2/3 of the energy is lost in the engine and drive chain. However, the energy conversion of solar electric vehicles is not limited by the Carnot cycle law, and the thermal efficiency is much higher, reaching 34-40%, and 90% of the energy is used to push the vehicle forward.

The disadvantages

The low solar conversion efficiency of 24% for the gallium arsenide based cell, and with the limited car size approximate 5.5 meter square. The solar panel could generating the most electricity of 3.3 KWH per day. In the uncertain the wether and quality issue, the even less energy will be produced.

The cost side is also a important method for consumer to measure.For car with the solar panel, cost on the research, development and material will be separately added on each consumer, thus clients will have less incentive to buy it.

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