The Development Status of Charging Mode of Pure EV for Home Use


Influenced by the current international situation, the global oil prices hit a new high, accompanied by the national macro policy guidance and increasingly acute environmental protection issues, the demand for new energy vehicles also continues to go up. According to the data of China Economic Net , in the first two quarters of 2022, the production and sales volume of China's automobile industry amounted to 12.117 million and 12.057 million respectively, of which, the production and sales volume of new energy vehicles amounted to 2.661 million and 2.6 million respectively, with a year-on-year growth of about 120%, and the market share exceeded 20% for the first time, amounting to 21.6%, which was realized three years ahead of schedule. The "14th Five-Year Plan" for a modern energy system put forward in the "new vehicle sales of new energy vehicles accounted for 20% by 2025" of the target. In particular, pure electric vehicles for domestic use are favored by the market for their advantages of low noise, energy saving and zero emission, and their sales continue to boom.

Pure electric vehicles for domestic use are non-operating pure electric vehicles owned by private individuals or individuals, with electric energy as their single power source, and the charging frequency is about 2~7 d charging times according to the domestic use scenarios. In addition to plug-in hybrids, superchargers, and other new energy vehicles, the domestic market share of pure electric vehicles for domestic use has reached 17% of the domestic vehicle market. The purpose of this paper is to illustrate the current development of the charging mode of pure electric vehicles for home use and to analyze and predict the trend of the charging mode by means of comparative research and case studies.

zeconex charging pile brand factory

Development Status of New Energy Vehicle Charging Industry at Home and Abroad

Foreign Development Status

Western developed countries, especially Japan, the United States, Germany and other veteran automotive powerhouse, new energy vehicles and related charging industry, basic research and construction layout started earlier, compared to China, the degree of perfection of its related policies and the depth of cooperation between the government and enterprises, is more complete and mature.

Domestic Development Status

Compared with the new energy vehicle charging industry in the western developed countries, China's technical research and accumulation in the relevant fields started late, but along with the country's strong support for the new energy vehicle industry on the macro level, and after taking the best of the best, learning from the relevant experience of foreign countries in the development of China's charging industry has made great strides, and even catching up with the trend. At present, China's new energy vehicle charging industry and charging infrastructure construction also ranks among the world's forefront, and in the world, has become the most invested and operated charging and switching equipment countries.

Explanation and Comparison of Three Charging Methods

External Plug-in Charging Method

The charging method of external plug-in charging (hereinafter referred to as plug-in charging) is that after the power battery of a pure electric vehicle is discharged, DC or AC power is input from the outside world and passes through the power battery in the direction opposite to that of the discharging current, so as to make it restore the power reserve, and the process is called the plug-in charging of the power battery.

This process is called the plug-in charging process of the power battery. The charging method of plug-in charging is divided into fast DC charging and slow AC charging.

Fast DC Charging (hereinafter referred to as fast charging)

Fast charging, also known as ground charging, is to charge the power battery directly by the high-intensity DC power output from the fast charging post, and the power battery can be charged to about 80% in a short time. The voltage of this charging method is generally between 150~400 V, and the power is large. The advantages of fast charging are high charging efficiency and short charging time, but fast charging requires high voltage and power for automobile power batteries, which may also lead to increased load on the thermal management system of the power battery and cause adverse effects on it.

Under the background of the continuous progress and popularization of power battery technology and fast charging technology, the range and charging speed of pure electric vehicles for domestic use are continuously improving, and the influence of fast charging on the reduction of vehicle battery efficiency is also gradually decreasing. Taking an ordinary 60 kW charging post as an example, it takes less than 30 minutes to charge a domestic pure electric vehicle from 20% to 75% of its range.

Slow AC Charging (hereafter referred to as slow charging)

Slow charging, also known as conventional charging and in-vehicle charging, is charging with portable charging equipment carried in the vehicle, using household power supply and charging piles. The charging current of slow charging is small, generally around 6~32 A, and the charging current is in the form of three-phase AC. Depending on the size of the current and the size of the power battery, it takes 8~12 h or even longer to fully charge a domestic pure electric vehicle by slow charging. It can be seen that the disadvantage of slow charging is very obvious. That is, the charging time is too long, but the cost requirements for charging are not high. More importantly, slow charging can deeply charge the power battery of a pure electric vehicle for home use, which has less impact on the decrease in battery efficiency and can extend its service life.

Charging Method of Battery Replacement in Power Exchange Stations

The charging method of battery replacement in power exchange stations (hereinafter referred to as power exchange) is: centralized charging, centralized storage and unified distribution of power batteries of pure electric vehicles for domestic use by centralized power exchange stations, and power battery replacement service for pure electric vehicles for domestic use in the power exchange stations.

For ordinary household users, although the power exchange mode can solve range anxiety and improve charging efficiency, it also has many problems. For example, in the process of power exchange, the mechanical connection between the battery box and the vehicle structure may be unstable, leading to wear and tear of the electrode plugs, and even generating sparks that may lead to potential safety hazards. There are three major challenges facing the power-switching charging method today: a. the high upfront construction cost of power-switching stations; b. the different technical standards and power battery standards of various vehicle companies; and c. the general lack of initiative by vehicle companies to share their technical standards. The above three points are three important reasons why it is difficult to popularize and promote the charging method of power switching in the end. However, in some specific areas, power switching has unique advantages and competitiveness, such as in the field of electric public transportation, where there are customized and scaled vehicles, and a closed-loop power switching model may be formed in these areas in the future.

The user experience of pure electric vehicles for home use is more convenient and faster, and the time cost of switching is almost comparable to the refueling efficiency of a fuel vehicle. However, in terms of cost, the investment in the preliminary construction of the power exchange facilities is quite huge, and the investment in the reserve batteries required by the power exchange station itself should also be taken into account, which will be a huge expense.

Wireless Charging Method

Wireless charging is a charging research result that has only entered the public's view in recent years, and it is a kind of non-contact and inductive charging technology. In the form of high-frequency alternating magnetic field energy, the power supply guide rail buried under the ground transmits the electric energy to the electric energy receiving end of pure electric vehicles for domestic use above the ground, so as to charge the power battery. Through this charging method, the vehicles can carry a small amount of power battery packs by themselves, and can prolong the mileage of the power battery packs, and at the same time, the non-contact form makes the charging process safer and more convenient.

At present, automobile wireless charging is only an attempt and innovation of charging method, but compared to the familiar wireless charging of cell phone, the charging frequency of automobile is relatively low, and not like the miniaturized wireless charging device of cell phone, which makes the automobile able to realize wireless charging at any time, and the wireless charging of the automobile must be driven to the designated place, so there is no way for wireless charging of the automobile in the present stage. Therefore, there is no way for wireless charging of automobiles at this stage to fundamentally achieve "charging and using at the same time, convenient and fast". Previously, some experts at home and abroad have clearly put forward the idea of "intelligent highway", which can be used to replenish the energy of running electric vehicles by laying wireless charging boards underneath the highway pavement, that is, "charging while driving".

Charging Pile

Comprehensive Comparative Analysis

Wireless charging charging mode, subject to the influence of many factors, in the current situation, to achieve practical application is still very difficult, because of the limited space, so not in the comprehensive comparative analysis of the discussion, comprehensive comparative analysis focuses on the plug-in charging and power exchange of the two charging modes of discussion. 3.4.1 Comparison of the investment in the early stage.

According to some data, at present, the construction of a power exchange station requires about 2 million yuan of equipment and 2 million yuan of power battery reserve, plus other costs, basically, the construction of a power exchange station requires about 5 million yuan of upfront investment, and the cycle of profitability of a power exchange station is too long. The construction cost of an ordinary charging pile is about 18,000 RMB, the construction cost of a fast charging pile is about 90,000 RMB, and the construction cost of a small charging station with 5-8 charging piles is about 100,000-800,000 RMB, which makes the cost of a power exchange station almost 5-10 times of the cost of a charging station.

Comparison on the Degree of Adaptability

At present, the power exchange stations that occupy a large scale in the market basically come from the new energy vehicle enterprises themselves and only provide power exchange service for their own models, which is in a situation of "each fighting on its own", with a low degree of generality and universality. Due to the independent production of pure electric vehicles of various automobile brands, there is no unified standard for power exchange within the industry, resulting in power exchange stations not being able to be networked, and even if a brand lays out more power exchange stations, for the time being, it is not possible to do the same thing as a fuel car going to a gas station to refuel, so that pure electric vehicles of any brand can be exchanged at the same power exchange station. The compatibility of most charging piles with the charging of domestic pure electric vehicles of various automobile brands is much better. After the release of the national standard for the general standard of charging piles, the newly built charging facilities have been manufactured and installed in accordance with the unified national standard, and the original charging facilities are gradually updating the plug-in charging interfaces to realize the unification of the plug-in charging standard for domestic pure electric vehicles.

Comparison on User Experience

Owners who buy and use pure electric vehicles for domestic use generally have charging piles at home, in their living quarters, or in the units where they often park their vehicles, so that they can combine their own needs with their own vehicle needs and make use of their leisure time or the nighttime power valleys for charging, thus reducing the impact of the long charging time on the time cost of using the vehicle. Although the speed of a single switch is fast, due to the difficulty of popularizing the switching station, the coverage is not wide enough, and the car owner has a high time cost on the way to and from the switching station, the coverage of the switching station and the user's actual use experience have a direct relationship.