1. Introduction to Charging Module
1.1 Development of Charging Pile
The charging pile industry has been growing for more than ten years and has entered an era of rapid growth. 2006-2015 was the embryonic stage of China’s charging pile industry. In 2006, BYD established the first car charging station at its headquarters in Shenzhen. In 2008, the first centralized charging station in China was built during the Beijing Olympic Games. At this stage, the charging piles were mainly built by the government, and social enterprise capital did not enter. 2015-2020 was the early growth period of charging piles. After the state issued the “Guidelines for the Development of Electric Vehicle Charging Infrastructure (2015-2020)” in 2015, it attracted some social capital to enter the charging pile industry. From this point in time, the charging pile industry officially has the attributes of social capital. 2020-to-date is the key growth period of charging piles. During this period, the government has issued several policies to support charging piles. In March 2021, charging was included in the construction of new infrastructure, stimulating industry enterprises to further expand capacity and increase production. So far, the charging pile industry is still in a key growth period, and the number of charging piles is expected to continue to grow rapidly.
1.2. Introduction to charging module companies
From the current type of the module, the existing charging modules include ACDC charging module, DCDC charging module, and bidirectional V2G charging module. ACDC is used for unidirectional charging piles, which is the most widely used and most widely used charging module. DCDC is used for photovoltaic charging of batteries and battery charging of vehicles, and is used in photovoltaic storage and charging projects or storage and charging projects. V2G charging module is to solve the future vehicle-grid interactive function or bidirectional charging needs of energy power stations.
From the supply relationship of charging piles, charging modules are mainly divided into two categories, one is self-production and self-use type, represented by TELD, Sinexcel Electric, KSTAR, etc.; the other is supply type, represented by INFYPOWER, UUGREENPOWER, Tonhe Elect, SZWINLINE, HUAWEI, Shenzhen Megmeet, ENSDS, etc.
1.3 Charging module market
The top three module manufacturers in terms of module shipments in 2022 are INFYPOWER, Teladian and Youyou Green Energy. Among them, INFYPOWER mainly accounts for overseas markets and power grid companies. Teladian, as a leading domestic charging operator, occupies half of the domestic market, followed by UUGREENPOWER, SZWINLINE, HUAWEI, etc.
The module market size and share in 2023. According to the annual summary and comparative analysis of each company, in the total charging module market including all participants in 2023, the top five companies in terms of market share are: INFYPOWER, UUGREENPOWER, Tonhe Elect, SZWINLINE, Sinexcel Electric; compared with 2023, Tonghe Technology has made obvious progress. The only unchanged thing is that INFYPOWER, which has long been at the top of the list, has maintained a market share of more than 33%.
2. Introduction To The Development Trend Of Charging Modules
With the advent of large-scale electric vehicles, simple charging piles are obviously unable to support the development of large-scale electric vehicles, and the charging network technology route has become a consensus in the new energy vehicle charging industry. It is simple to make charging piles, but it is very complicated to make charging network technology. The charging network is a cross-industry and cross-professional ecological system, involving at least 10 fields of technology such as power electronics, dispatching control, big data, cloud platform, artificial intelligence, industrial Internet, substation distribution, intelligent environmental control, system integration, and intelligent operation and maintenance. The deep integration of these technologies can ensure the integrity of the charging network system.
The core technical barriers of the charging module lie in the topological structure design and integration capabilities. The key components of the charging module are power devices, magnetic components, resistors and capacitors, chips, PCBs, etc. When the charging module is working, the three-phase AC power is rectified by the active power factor correction (PFC) circuit and becomes DC power to supply the DC/DC conversion circuit. The software algorithm of the controller acts on the semiconductor power switch through the drive circuit to control the output voltage and current of the charging module, thereby charging the battery pack. The internal structure of the charging module is complex, and a single product contains a relatively large number of components. The topological structure’s design directly determines the product’s efficiency and performance, and the heat dissipation structure design determines the heat dissipation efficiency of the product, which has a high technical threshold.
As a power electronic product with a high technical threshold, the charging module needs to consider many parameters in order to achieve high quality, such as: volume, mass, heat dissipation method, output voltage, current, efficiency, power density, noise, operating temperature, standby loss, etc. Previously, charging piles had low power and poor quality, and the requirements for charging modules were not high. However, under the trend of high power, low-quality charging modules will cause major problems in the subsequent charging pile operation stage and increase the subsequent operation and maintenance costs. Therefore, charging pile companies’ requirements for charging module quality are expected to further increase, and higher requirements will be placed on the technical capabilities of charging module manufacturers.
2.1. Charging module standardization
The standardization of charging modules is constantly improving. The State Grid has issued standardized design specifications for charging piles and charging modules within the system:
(1) Charging pile “six unifications”: unified electrical performance, unified structural layout, unified special component design, unified general device selection, unified appearance structure, and unified equipment installation;
Tonghe Technology’s products are mainly 20kW high voltage wide constant power modules and 30kW and 40kW high voltage wide constant power modules that meet the State Grid’s “six unifications” standards;
(2) Charging module “three unifications”: unified module appearance size, unified module installation interface, and unified module communication protocol. The standardization of charging pile and charging module design specifications has to some extent solved the problem of poor product compatibility in the market in the past, and will effectively promote the rapid development of the charging pile industry.
2.2 Charging modules develop towards high power
The power of a single charging module has gradually evolved from the early 3kW, 7.5kW, and 15kW to the current 20kW, 30kW, and 40kW, and continues to move towards higher power levels such as 50kW, 60kW, and 100kW. This power upgrade not only means that more power can be output per unit time, but also significantly increases the value and profitability of charging module products. With the advancement of technology and the continuous expansion of the market, the charging module industry will continue to usher in more development opportunities.
For example, in the current charging pile market where the single-gun power is 60-120KW, the 15KW module can also meet the market demand, but many pile companies use 40kW modules with lower per-watt cost based on the cost of the whole machine. In fact, the more system modules there are, the smaller the impact of single module failure on the overall system. Car owners do not need to bear the risk of extended charging time due to reduced system availability. When charging pile operators make flexible charging intelligent allocation, they expect the module granularity to be smaller, which is easier to schedule and allocate, reduce power waste, and a single failure has less impact on the availability of the system, and the requirements for timeliness of operation and maintenance will also be reduced. Therefore, the current layout of mainstream companies is relatively complete, and the market coverage is mainly 30/40kW products.
In November 2022, Sinexcel Electric successfully launched the first 50kW DC charging module in China, which is equipped with SICMOS core devices inside, with a maximum efficiency of more than 97%, and has obtained sales certificates for the domestic market.
At the 2022 Third China International Charging Pile Operator Conference, Eurotron released its 75KW ACDC product for the first time, with an output voltage of up to 1000V DC and a peak efficiency of 97%.
3. Diversification Of Heat Dissipation Methods
The current development direction of charging module technology, from the perspective of heat dissipation methods, is roughly divided into three categories of products: one is the direct ventilation type module, which is the mainstream product type in the market and is produced by all module companies; one is the independent air duct and glue-filled isolation type module, the former is represented by UUGREENPOWER, and the latter is represented by INFYPOWER and Tonhe Elect; one is the full liquid cooling heat dissipation charging module, represented by INFYPOWER and HUAWEI.
The three types of charging module products have technical iteration characteristics, and due to the principle of economic use, the heat dissipation method is improved and optimized. For charging pile operating companies, the failure rate of charging piles and noise nuisance are two major problems. Among them, the failure rate of charging piles directly affects the profitability of the site and the user experience. The main reason for the failure of charging piles is the failure of the charging module. The air-cooled module is the most widely used product type at present.
4. High Current And High Voltage Technology
As the mileage gradually increases, challenges such as shortening charging time and reducing usage costs need to be faced. The primary task is to optimize the module size to achieve power upgrades. Since the power of the charging pile mainly depends on the power superposition of the charging modules, and is limited by the product volume, floor space and manufacturing cost, simply increasing the number of modules is no longer the best solution. Therefore, how to increase the power of a single module without increasing the additional volume has become a technical problem that charging module manufacturers urgently need to overcome.
DC charging equipment achieves excellent fast charging capabilities through high current and high voltage technology. With the gradual increase in voltage and power, this puts forward more stringent requirements on the stable operation, efficient heat dissipation and conversion efficiency of the charging module, which undoubtedly sets higher technical challenges for charging module manufacturers.
Facing the market demand for high-power fast charging, charging module manufacturers need to continuously innovate and upgrade the underlying technology and build their own core technology barriers. This will become the key to future market competition. Only by mastering the core technology can we be invincible in the fierce market competition.
(1) High current route: low promotion level and high requirements for thermal management. According to Joule’s law (formula Q=I2Rt), the increase in current will greatly increase the heat generated during charging, which places high demands on heat dissipation. For example, Tesla’s high-current fast charging solution, its V3 supercharging pile has a peak operating current of more than 600A, which requires the use of thicker wiring harnesses. At the same time, it has higher requirements for heat dissipation technology, and can only achieve a maximum charging power of 250kW at 5%-27% SOC, and efficient charging is not fully covered. At present, domestic car manufacturers have not made major customized changes to the heat dissipation solution, and high-current charging piles rely heavily on self-built systems, which has high promotion costs.
(2) High-voltage route: This is the mode currently commonly adopted by car manufacturers, which can take into account the advantages of reducing energy consumption, improving battery life, reducing weight, and saving space. Currently, due to the voltage resistance of silicon-based IGBT power devices, the fast charging solution commonly adopted by car companies is the 400V high-voltage platform, that is, a charging power of 100kW can be achieved with a current of 250A (100kW power charging for 10 minutes can travel about 100km). Since Porsche launched the 800V high-voltage platform (achieving 300KW power and reducing high-voltage wiring harnesses by half), major car companies have started research and layout of the 800V high-voltage platform. Compared with the 400V platform, the 800V voltage platform has a smaller operating current, which saves wiring harness volume and reduces circuit internal resistance loss, thereby improving power density and energy efficiency in disguise.
5.Reliability Requirements Are Getting Higher And Higher
Under the pressure of low cost, charging piles still face great challenges to be safe, reliable and stable. Since charging piles are installed outdoors, dust, temperature and humidity are not well protected, and the environment is relatively harsh. Under special working conditions such as high latitudes, high cold and high altitudes, the performance requirements of charging modules are extremely high.
At present, the 15kW module mainly dissipates heat by forced air cooling, which inevitably brings interference such as dust, corrosive gases and moisture. Therefore, module failures are mainly concentrated in the phenomenon of “hot explosion” caused by the environment. In order to overcome the adverse consequences of forced air cooling, natural cooling (mainly relying on heat sinks) is one of the possible effective options.
6. V2G Bidirectional Charging Technology
In addition to the traditional function of charging electric vehicles, the charging module is also developing bidirectional charging technology. The development of bidirectional modules has further enabled V2G technology and V2H technology to be realized, playing a positive role in peak shaving and valley filling, balancing power load, and improving the efficiency of charging piles.
The photovoltaic storage and charging integration policy provides top-level policy design for intelligent and orderly charging and bidirectional charging and discharging, and determines the direction for charging stations to participate in grid peak and valley regulation, virtual power plants, aggregated transactions, and integrated charging and storage. However, these are inseparable from the hardware foundation of bidirectional V2G charging modules. The earliest domestic manufacturer to pre-research bidirectional V2G charging modules is Infrared. At present, Infrared V2G module market share is in an absolute advantage, and V2G charging piles in the power grid system are the only one.
7. Intelligent Operation and Maintenance
There are many challenges in the current charging operation market. First, the operation and maintenance costs of charging stations are high. For operators using charging equipment with high failure rates, the operation and maintenance costs exceed 10% of the operating income. Insufficient intelligence leads to the need for regular inspections, large investment in operation and maintenance manpower, and untimely operation and maintenance will also lead to poor user charging experience; second, the equipment life cycle is short, and the power and voltage of charging piles built in the early stage cannot meet the charging evolution needs of future vehicles, wasting the initial investment of operators; third, low efficiency affects operating income; fourth, DC charging piles are noisy, which directly affects the site selection of stations. In order to solve the pain points of charging facilities and follow the development trend of the industry.
Take Huawei HUAWEI HiCharger DC fast charging module as an example. In terms of intelligent operation and maintenance, HUAWEI HiCharger DC fast charging module also brings new value features to customers. Through the temperature data collected by internal sensors and combined with artificial intelligence algorithms, HUAWEI HiCharger can identify the blockage of the dust screen of the charging pile and the blocking state of the module fan, and remotely remind operators to implement accurate and predictable maintenance, eliminating frequent on-site inspections.
To solve the noise problem, the HUAWEI HiCharger DC fast charging module provides a silent mode for noise-sensitive environment applications. At the same time, the temperature of the sensor in the module is monitored to accurately adjust the fan speed according to the change of ambient temperature. When the ambient temperature drops, the fan speed decreases, reducing the noise and achieving low temperature and low noise.
The HUAWEI HiCharger DC fast charging module adopts full glue filling and full isolation protection technology to solve the problem that the air-cooled charging module is easily affected by the environment and fails. Through dust accumulation and high humidity tests, accelerated high salt spray tests, and long-term reliability tests in Hainan, Xishuangbanna, Dunhuang, Lhasa and other fields, the long-term reliability of the module in harsh scenarios has been verified, which greatly reduces the operator’s operation and maintenance costs.
As a new iteration of the previous generation of charging modules, the overseas version of the 20kW DC fast charging module has a maximum efficiency of 96.55%, and the domestic version of the 30kW has a maximum efficiency of 96.4%. Through the application of efficient patented topology, efficient control algorithm and low-loss devices to reduce losses, smooth air duct design, precise fan speed regulation, reduce the additional losses caused by heat dissipation, and achieve the optimal efficiency of the module.
