Fly away! How hard do humans fight to give EV replenishment?

[Aika Auto Industry News Original]

Since the wave of new energy swept the global automotive market, the replenishment of pure electric models has become a topic of common concern in the automotive industry and even the whole society. In order to make the "short-legged monsters" more efficient, convenient and more economical as their oil-drinking predecessors, people can say that they can do everything to the extreme, and new tricks and old methods are put together. Let's take a look at the whimsical ideas about electric vehicle power replenishment.

Solar charging stations that can only "hit the auxiliary"

As we all know, the construction of charging stations and piles cannot be expanded in a disorderly manner, and it is necessary to take into account the load of the local power grid and the cost of connecting the charging station to the power grid. But what if the electrical energy provided by the charging station/pile is completely independent of the grid? Sounds pretty good, right? This thing does exist!

As early as 2016, a domestic photovoltaic company built the first off-grid solar charging station in Dongguan, Guangdong Province, which can indeed be completely independent of the power grid operation, only using solar energy storage for pure electric vehicle charging, the power grid will not cause pressure, and even in the area of no electricity to build and operate.

Compared with grid-connected solar charging stations, off-grid types are more rare, limited by the energy efficiency of solar panels, off-grid solar charging stations do not have the conditions for large-scale promotion.

Coincidentally, between 2020 and 2021, Electrify America, a subsidiary of the Volkswagen Group, has also laid a number of off-grid solar charging stations in more remote areas of California, which are full of light all year round and can provide the required power for the energy storage facilities of these charging stations, so vehicles can recharge these charging stations during the day or at night.

It seems to be a very ideal way to replenish energy, but why is there no promotion?

The biggest problem is actually the efficiency of energy collection, to the above-mentioned off-grid solar charging station located in Dongguan, Guangdong Province, as an example, its daily power generation is only about 80 kWh of electricity, such power generation for today's increasingly large battery capacity of electric vehicles is almost like a joke, even in 2016, the more mainstream BAIC EV160 with 25.6kWh batteries, the power from 30% to 80%, the off-grid solar charging station can only serve 6-7 cars a day.

Even with large-area solar panels, solar charging stations that want to provide fast charging services for pure trams with large-scale traffic still need to be connected to the local grid system.

The off-grid solar charging station built by Electronify America in rural California faces the same problem, relying on a 4.28kW tracking solar array to generate electricity, equipped with a capacity of 32kWh energy storage batteries, such specifications simply can not cope with the demand for high-flow pure electric energy replenishment. This is also why this type of charging station only provides 6kW AC charging piles.

Sunrun Company, which specializes in the manufacture of solar panel arrays, has calculated the scale of solar panels for charging stations, and if it wants to maintain the normal operation of a fast charging pile with 150kW charging power, it is necessary to lay 469 solar panels to power it; and Tesla V3 overcharge (maximum power 300kW) or even a higher power 335kW-350kW supercharge pile produced by ABB needs more than 1000 solar panels to power it. The total area of these solar panels can reach more than 1800 square meters, and it is only a charging pile! According to the current specifications of 4-6 fast charging piles in the mainland high-speed service area, the solar panels required for a charging station are described as "shading the sky".

According to the calculations of solar energy companies, to maintain the normal operation of a 150kW charging power fast charging pile, relying solely on solar energy requires the laying of 469 solar panels with a total area of nearly 1,000 square meters, which is described as "shading the sky" on such a scale.

In fact, as a leading Tesla in the pure electric vehicle industry, its CEO Elon Musk also proposed the idea of off-grid solar charging stations in 2016, but until now, including tesla's construction of photovoltaic storage and charging integrated superchargering stations in Tibet, it exists in the form of grid connection, and cannot be completely independent of large-scale operation outside the grid system.

Tesla has long been involved in the research and development of solar charging stations, and has built integrated superchargering stations with light storage and charging in sunny areas such as Tibet.

Off-grid solar charging mode is not suitable for large-scale application to charging stations, but it is an ideal form of energy replenishment for private users who have the conditions to install corresponding equipment.

Although the off-grid solar charging form can not be applied to the charging station on a large scale for the time being, but in fact, this form can be used for home users, and there are many companies at home and abroad that are promoting solar off-grid charging schemes for home users. Although the efficiency of converting solar panels into electricity is not enough for fast charging or overcharging, the impact of this inefficiency is not so unbearable for home users who use slow charging, and the electricity costs saved by converting electricity through solar energy are quite a real benefit.

Charging Highway: The Battle Between Heaven and Earth

The use of charging piles to charge or to change the power station is the most common way of filling the energy of pure electric vehicles, but even if it is a power exchange mode known for its speed, it still requires the driver to drive to a specific location, and it takes a few minutes to complete the energy replenishment process. Is there a remedial solution that does not require additional time costs during the use of the car?

The French took the lead in trying solar charging roads in 2016, but the results were quite unsatisfactory, with problems such as durability, power generation efficiency, and road noise emerging.

The first to make a relevant attempt were the French. In 2016, Colas, a large French civil construction company, built a 1-kilometer-long solar charging road - "Wattway" in the area where the Allies landed 72 years ago , Normandy in northern France, don't look at it, it is only 1 kilometer, but this road cost up to 5 million euros because of the laying of more than 2800 solar charging panels. It should be noted that this road can not directly charge the vehicle during the driving process, but by converting solar energy into electricity to power road facilities (such as street lights), nearby charging stations, and at the same time, when snowfall, it can also automatically melt the ice and snow by collecting the heat generated when solar energy is collected.

Despite Colas' promise to the public at the beginning of the "Wattway" that the road could withstand the passage of any large vehicle, it made public the structure of the pavement: a layer of high-intensity translucent material as the surface of the pavement was laid on top of the solar charging panels as protection. But in fact, in the third year of the road's opening, the road has been completely damaged, and the surface protective material will directly break when large vehicles pass.

Within three years of use, the €5 million Wattway was in ruins.

The problems of this road are far more than this, the use of special materials only takes into account the need to collect solar energy, but the excessive road noise generated by vehicles disrupts the lives of surrounding residents every day; even in the early days of construction, the road surface is intact, its power generation is less than half of the expected...

Just over a year after the completion of the Watway in France, at the end of 2017, Jinan, Shandong Province, China, also completed and opened a solar highway with a total length of 2 kilometers. The principle is basically the same as that of the French Wattway, but the fate is more tragic. After the sixth day of operation, the 2-kilometer-long solar highway was extensively damaged and several solar panels were stolen. As of 2019, only more than ten meters of solar panels remain in this section.

In 2017, Jinan, Shandong Province, built a solar highway about 2 kilometers long, and the fate of this road is similar to that of Wattway.

It seems that the model of laying solar panels on the road will not work, but the idea of charging roads has not been abandoned. The Swedes and Germans came up with a "new" idea for charging roads, and you asked me why I put them in quotation marks? Look down and you'll see.

The Swedes' "new" thinking is actually quite traditional: trams. In 2018, Swedish road construction company eRoad Arlanda built a 2-kilometer charging road on the outskirts of the capital Stockholm. Compared with the above two solar roads, this road in Sweden can really achieve the function of instantly charging passing vehicles, but only if the vehicle needs to install a connecting arm on the chassis.

The Swedes' tramway, while not new, is practical enough.

Located about 2 kilometres outside Stockholm, the road can recharge vehicles with connecting arms, but it's just as expensive.

Through this connecting arm, the electricity transmitted by the live track laid on the road section of the road is charged into the battery in the car. The connecting arm can be automatically disconnected after the vehicle has left the charging road. The road is equally expensive, costing around £1.4 million (about 11.62 million yuan) per mile. But although it doesn't look very tall and expensive, at least this rail charging road is much stronger than paving with solar panels, and countries including Sweden and Germany are also promoting the technology.

The live rail transfers electricity to the car's battery through the connecting arm, which automatically disconnects from the track and is retracted back into the car as the vehicle leaves the section of the road.

If the tramway is called "escape", then the next idea is to play "flying": in Germany, if you drive from Frankfurt to Darmstadt, you will find that there will be a section of about 3 kilometers on the way, and the entire road is installed with an overhead power grid, which can charge electric vans with overhead pantographs. As of October 2021, there are already 15 kilometres of overhead power grids in Germany, and in Sweden, the E16 motorway from Gavle to Sandvik is also being built.

The Germans have used an overhead grid to charge vehicles with overhead pantographs, and by October 2021, a total of 15 kilometers of elevated power grids have been installed throughout Germany.

Seeing this, some netizens will definitely say: Isn't this the same as the "big braid" bus that has appeared in many cities in China? Indeed, from a technical point of view, neither the rail charging road nor the combination of overhead power grids and pantographs is a new technology. However, the next wireless charging road should be regarded as cutting-edge technology.

In December 2020, Israeli technology company ElectroReon laid the world's first wireless charging road, Smartroad Gothland, in Visby, Gotland, Sweden, which works by laying an induction coil underneath the asphalt layer of the 1.65-kilometer-long road to enable dynamic wireless transmission of electricity for freight vehicles equipped with induction equipment.

Demonstration video of wireless charging highway

In the course of many tests, vehicles traveling at 60km/h can ensure that 70 kW of charging power per hour is obtained, and even the common snowfall in the local area does not affect the efficiency of wireless charging; in Tel Aviv, Israel, and Karlsruhe, Germany, there are also wireless charging roads using the same technology.

Whether it is rail charging, overhead grid pantograph charging or more advanced wireless charging road technology, the success of the "charging road" test has made Sweden and Germany optimistic about the prospect of "solving the EV power supply dilemma", and then willing to make large-scale infrastructure investment in related technologies: Sweden plans to recharge 2,000 kilometers of roads in the country by 2030; while Germany plans to spend 12 billion euros to achieve 4,000 kilometers of road rechargeable by 2030.

Given the success of the pilot phase, both Germany and Sweden plan to invest heavily in the promotion of charging road technology.

Conclusion: As Deng Gong said: "Regardless of black cats and white cats, the one who can catch mice is a good cat." "The same is true of all kinds of new and old charging technologies and ideas. As long as it can solve the problem of pure electric vehicles in the right scene, it is a good way. The above content introduced in this article is only a small corner of human wisdom projected into the field of EV replenishment, I believe that as more enterprises and experts in related fields devote themselves to the field of new energy, there will be newer, more efficient and more market-oriented energy technologies in the future to be excavated.