Low-power DC products, are a new charging solution for future electric vehicles, are to replace on-board chargers and AC charging piles with a series of non-on-board DC chargers (DC charging piles):
1. Replace the 11kW/20kW on-board charger (OBC) and related on-board components and the corresponding 11kW/22kW AC charging pile with an 11kW/22kW wall-mounted DC charging pile.
This alternative logic is the most acceptable to car companies, because the proportion of car owners who have the opportunity to use 11kW and 22kW is very small, even if it is conservative, the development of 11kW OBC can be terminated first; For a small number of car owners who have the conditions to use 11kW/22kW, 11kW/22kW DC piles are optional. This will reduce “waste at scale”. The term I use is “mass waste”. This view has not encountered any objections, so the development of 20kW DC piles has become a consistent choice. Friends who have a heart may have noticed that I posted an article in 2018 emphasizing that 11kW OBC is “seeing the light and dying”, and I hope that the OBC industry will not waste time.
The demand of car companies is independent air duct, which is a long-term mainstream solution. The aftermarket is still dominated by forced air cooling.
2. Replace 7.6kW OBC and related on-board components and corresponding 6kW AC charging piles with 7kW wall-mounted DC charging piles.
7kW will be a bloody and large-scale market. Only scale can survive. 7kW will have many product forms, and the BOM price difference will reach 2000,<> yuan. Forced air cooling, independent air ducts and natural cooling products will all be available on the market.
Ride-hailing and taxis are 100% free of OBC. Traditional conservative car companies select some models to use OBC as an option and test the water first. Some models simply removed the OBC. Some car companies, such as NIO and JIDU Automobile, have removed the OBC of all models. The trend of the domestic market moving will become more and more obvious. I interviewed more than 100 car company friends face-to-face, and the final conclusion was: if one or two car companies are removed, they will be removed. However, the European market is not expected to remove OBC until the DC bidirectional charge and discharge scheme matures.
3. Replace the 3.5kW OBC and related on-board components and the corresponding Mode 3 AC charging box with a 3.<>kW mobile DC charging pile.
If developed according to the low-power DC charging standard, the process difficulty of this product is very complicated. Small businesses without precipitation are holding back. The 3.5kW is ideal for minivans, which can be charged at home and put in the trunk as an emergency recharge. There is no reason for minivans to keep OBC. The vast majority of minivans do have OBC removed.4. Replace the 2.2kW OBC and the corresponding Mode 2 AC charging case with a <>kW portable DC charging pile.
The 2kW is the best choice for A00-class models and hybrid models, and can also be charged at home or put in the trunk as an emergency power supply. There is no reason for the A00 and hybrid models to keep the OBC. Geely’s Panda mini EV and Dongfeng Nissan’s hybrid models have been the first to remove OBC.
4. Replace the inverter function of bidirectional OBC with 3kW/7kW discharge motor to meet the needs of camping.
Although camping is a niche need, the scene of a bonfire lit by the sea is easy to make people imagine beautifully. When buying a car, consumers always feel that it would be nice if there was a function, but in fact, this demand is once every two years for one in a thousand people. It’s human nature. This demand in the Chinese market, I think can not replace consumer energy storage products, because China’s seaside and parking lot are not connected, but now also developed some special camping sites, you can drive the car directly to the campsite.
This discharge motor can be used well with consumer energy storage products, because the power of consumer energy storage products is only a few hundred watts, and the power of the energy storage battery is gone, and the power can be replenished from the car by the discharge motor.
Dongfeng Nissan Ariya chose the UCD3500 of Energy Efficiency Electric as the discharge motor.
The highest level of power electronics
In 2002, only 3.3kW of AC/DC PFC was commercialized, and passive PFC was used for 6kW, with a power factor of only 0.7. The widespread mass production of three-phase Vienna was a matter of 2005. At that time, 6kW was considered a lot of power. In 2015, when the charging pile began to be popular, the mainstream power of the charging module was 15kW, but it was not stable, and the “bomber” was flying all over the sky. A company relied on the first generation of charging module products and new energy concepts to achieve the market, but the second generation of products did not keep up, and soon entered a state of brain death. In 2016, the concept of constant power became popular. In 2017, 20kW began to be accepted. Mass production of 2019kW began in 30, and the ultra-wide operating voltage range of 200-1000V became widespread. Mass production of 2022kW will begin in 40. Technology iterations are fast. In 2016, listed companies engaged in charging modules withdrew from the competition. Rich companies can’t do power. There are very few companies like Energy Efficiency Electric that continue to innovate and iterate technology!
The 20kW adopts the method of independent air duct, which is the insistence of WattSaving’s energy efficiency and NIO. In October 2018, the Energy Efficiency Electric team and the NIO team conducted a thorough discussion and decided to abandon forced air cooling and water cooling and adopt an independent air duct technology route.
Before October 2018, the Energy Efficiency Electric team developed a 10kW independent air duct product driven by XPENG. At that time, this product was a very radical concept, hoping to have 7kW in the trunk of the car, take it out and hang it on the trunk of the car to charge.
In December 2018, the Energy Efficiency Electric team and GEELY Automobile collaborated to develop a 12.3kW portable with independent air ducts. Now that I think about it, we are going well forward, so radical. When slow charging DC becomes a 5% fact, we can tell stories, stories about vision.
On August 2020, 8, NIO’s 31kW 20kW went on sale, and car companies began to follow suit frantically. Li Peng, “premier”, who has always been low-key, also posted a high-profile circle of friends.
In 2019 and 2021, two car companies in Beijing and Hangzhou resolutely abandoned independent air ducts and insisted on choosing 20kW with forced air cooling. But in the end, the two 20kW, which cost millions of development costs, could not be accepted by the market, wasting time and development costs. The failure of these two car companies in forced air cooling has made the market realize that noise and protection are rigid needs for the To C market. Even in 2020, more than half of the people within NIO’s R&D insist that forced air cooling is the best choice for 20kW.
The market has come to a conclusion. Independent air ducts are the best choice for 7kW-20kW low-power DC charging products.
Single ultra-high power (now up to 60kW), small size, ultra-wide voltage range, new process, new heat dissipation method, these are all concepts and products that did not exist in the field of power electronics before 2018, so I think that professionals in the field of power electronics give me the assertion that “low-power DC products represent the highest state of power electronics technology“ is acceptable.
Convergence of power electronics, embedded technology and Internet of Things technologies
The entire DC charging pile system includes a large number of digital control units (referred to as CPU units). The high-end DC charging pile includes the following CPU units:
1. PFC of the charging module
2. DC/DC of the charging module
3. Charge controller
4. Communication controller
5. Fan control board (high-end charging pile controls each fan separately)
6. Light board (complex lamp language design, using separate single-chip microcomputer control)
7. Bluetooth module (most charging piles do not customize the software of the Bluetooth module, and the software is directly burned and shipped by the Bluetooth module supplier)
8. 4G module (the charging pile does not customize the software of the 4G module, and the software is directly burned and shipped by the 4G module supplier)
The system framework diagram between the most important CPU units is as follows.
In addition to the fact that these underlying hardware require embedded software support to realize the various functions of the entire charging pile system, the charging piles of car companies need wireless networking. Car companies have their own cloud platforms. Cloud platform software development, mobile APP or mini program software development, is a typical Internet of Things software technology. These CPU units are OTA (over-the-air technology, i.e. remote upgrade) through the cloud platform. The DSP or ARM of the PFC of the charging module, the DSP or ARM of the DC, the ARM of the charging controller, the ARM of the communication controller, the microcontroller of the fan control board, and the microcontroller of the light board are remotely upgraded by OTA.
To play with the above, commercialize and mass produce stability, for those who make products, they are clear – this obviously requires a long way to go!
There won’t be a few who can really stick to doing well! Energy Efficiency Electric adheres to the core values of “people are everything, people and platforms achieve each other”, focuses on the growth of each employee, and focuses on the improvement of each employee’s personal competitiveness. Under the premise of believing that the choice of this track is correct, Energy Efficiency Electric only believes that it will be a matter of course.
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