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Key Components of EV Charging

Time:2024-03-27   Author:As Beam   Browse:

What are the important components of charging stations? What roles do each of the components play? Below, we will share detailed explanations of the 6 major components of charging stations, hoping to be helpful to you.


1.Charging Module

The charging module, also known as the power module, is the "heart" of the charging station, accounting for about 50% of the hardware cost of the charging station, and hardware costs account for 90% of the total cost.

In DC charging stations, the charging module converts AC power to DC power, which is crucial for the overall performance and safety of the charging station. Here is a diagram from YouYou Green Energy's prospectus:

Starting from the diagram above, brief introductions to important components are made below, including: vehicle power supply, distribution system (relays, fuses), film capacitors, metal soft magnetic powder cores, and wiring harnesses (cables + connectors).

EV Charging.jpg


2.Vehicle Power Supply

(a) Overview

The biggest difference in core technology between new energy vehicles and traditional vehicles is the "three-electric" system: 1) Power battery assembly, battery cells, battery pack, battery management system, etc.; 2) Motor assembly, drive motor, motor controller, etc.; 3) Electronic control assembly, on-board charger (OBC), on-board DC/DC converter, high-voltage distribution box, etc. Among them, the on-board charger OBC and the on-board DC/DC converter are collectively referred to as the vehicle power supply.


(b) According to Weimaisu's 2020 prospectus, the vehicle power supply specifically includes:

On-board charger, which refers to the charger fixedly installed on the vehicle, used to efficiently convert grid voltage into battery pack voltage, converting input AC power to DC power for charging. In other words, OBC is only required when charging with AC power (slow charging).

On-board DC/DC converter, which converts high-voltage DC power input from the electric vehicle battery into low-voltage DC power, providing power for low-voltage electrical devices such as air conditioning, lights, windshield wipers, electronic instruments, and safety airbags.

Integrated vehicle power supply products, which integrate multiple components such as on-board chargers and on-board DC/DC converters, forming smaller, more precise, and lower-cost integrated vehicle power supply products.


(c) Trends in the development of vehicle power supply under high-voltage fast charging:

Integration: By sharing parts of circuits, control chips, etc., material costs can be saved, volume and weight can be reduced, costs can be lowered; it is conducive to software development under a unified software architecture, improving efficiency; reducing the number of components, reducing production management difficulty, improving production efficiency; reducing aftermarket service pressure; optimizing space layout.

Currently, physical integration is common; while the magnetic integration scheme used by Weimaisu and others, under the premise of ensuring unchanged output performance, significantly reduces the material usage by largely reusing power devices through magnetic integration control and decoupling core technologies, effectively reducing costs and improving efficiency.

Bidirectional charging: Bidirectional OBCs can meet the needs of bidirectional charging and discharging of new energy vehicles, including V2L (Vehicle-to-load), V2V (Vehicle-to-vehicle), V2G (Vehicle-to-grid), etc.

High voltage: OBCs are evolving towards high power directions such as 11kW/22kW.


Application of third-generation semiconductors: The replacement of traditional silicon-based materials by silicon carbide in vehicle power supplies is a general trend. Third-generation semiconductor materials have advantages such as high power characteristics, high efficiency and low loss, high-frequency characteristics, etc., making them more suitable for making high-temperature, high-frequency, high-power, and radiation-resistant devices.


(d) Under the trend of high-voltage fast charging, areas where vehicle power supplies may not be favorable:


As mentioned above, OBCs are only required when charging with AC power.

Therefore, in the medium and short term, the impact of DC fast charging is not significant; but in the long term, the comprehensive deployment of high-voltage fast DC charging piles may to some extent replace OBCs. In fact, in 2021, the NIO ET7 model cancelled the AC charging port for the first time, and subsequent new models followed this design. In the future, household AC charging piles may also have the possibility of migrating OBCs from vehicles to the inside of charging piles.



3.Distribution System

The distribution system of new energy vehicles coordinates with relays and fuses to effectively protect loads and batteries. With the significant increase in voltage and current in the 800V architecture, the requirements for relays and fuses are increased.

(a) Relays

Relays are automatic switching components that play a role in circuit control and protection, and are essential components for electrical automation control and protection.

High-voltage DC relays are core components of new energy vehicles;

In traditional oil-powered vehicles, 45 low-voltage relays at 12V are usually used, with a unit price of about RMB 3-4, and the value of a single vehicle is about RMB140-180. In new energy vehicles, in addition to 45 automotive relays, usually 5-8 high-voltage DC relays are required, with a current unit price of about 80 yuan, and the value of a single vehicle is about RMB400-640.


Under high-voltage architecture, when relays cut off circuits, more serious arcing phenomena may occur, so the requirements for withstand voltage level, current carrying capacity, arc extinction, service life, etc., of products are increased. Some securities firms predict that in the future, the value of a single vehicle for high-voltage DC relays will reach RMB450-800, with a growth rate of about 12%-25%.


(b) Fuses


Overview: Fuses are devices for overcurrent protection of circuits. When a short circuit or overload occurs in the circuit, the thermal effects generated by overcurrent cause the fuse element to melt and vaporize, creating a gap, and an arc is generated. The fuse cuts off the faulty circuit by extinguishing the arc, thus playing a protective role in the circuit.


Under the same conditions, fuses can interrupt tens of times the maximum current of other switch protection devices, and the maximum current and fault energy passed through are less than one percent of other protective devices. The irreplaceability of fuses is reflected here.


Industry chain: Fuses are mainly composed of fuse elements, arc extinguishing medium, M-effect point, insulation tube shell, contact terminal, and indicator. According to Zhongmelt Electric's prospectus in April 2021, the fuse industry chain is as follows:


New energy electric vehicles drive fuse demand

Automotive fuses are divided into low voltage and high voltage.

Low-voltage applications generally have voltages below 60VDC and are mainly used to protect low-voltage loads in vehicles (such as headlights, power windows, windshield wipers, etc.), both oil-powered and electric vehicles.


High voltage is mainly applicable to new energy vehicles, with voltages generally ranging from 60VDC to 1,500VDC, mainly used to protect main circuits (large current charging and discharging of batteries, vehicle drive circuits), auxiliary circuits (air conditioning, PTC heating, slow charging, etc.), and direct current charging pile circuits. Under the trend of high-voltage fast charging, incentives/intelligent fuses are needed for active protection:


Excitation fuse: It can actively cut off the fault current when the excitation device is triggered by a control signal, that is, it can open protection when a fault is expected to occur, while traditional fuses can only protect after the fault current occurs, resulting in higher power consumption and weaker protection effectiveness. Intelligent fuse: It is a further upgrade of the excitation fuse, which can customize protection characteristics according to requirements, automatically trigger protection actions, and can also accept external control signals for active disconnection, providing integrated active and passive protection.


4.Film Capacitors

(a) Overview of Capacitors Capacitors are indispensable passive components that have the function of allowing alternating current to pass through while blocking direct current. The basic structure consists of two metal conductor materials separated by an insulating dielectric, forming two electrode plates. After charging, the two electrode plates will each store an equal amount of positive and negative charges, thus becoming a "charge storage container." Capacitors play important roles in tuning, bypassing, coupling, filtering, and energy storage in circuits. According to different insulating dielectric materials, capacitors are divided into ceramic capacitors, aluminum electrolytic capacitors, tantalum electrolytic capacitors, and film capacitors, among others.


(b) Overview of Film Capacitors Film capacitors use metal foil as electrodes and plastic films such as polyester, polypropylene, polystyrene, or polycarbonate as dielectrics. Film capacitors with different dielectric materials have different characteristics. Film capacitors have advantages such as non-polarity, low dielectric loss, long life, excellent high-frequency and temperature characteristics. With the expansion of high-frequency and high-current application scenarios, the market share of PP (polypropylene) film capacitors with excellent high-frequency characteristics continues to increase.


(c) Application of Film Capacitors in New Energy Vehicles

Inverters: Efficient inverter technology requires powerful power modules for inversion, matching DC-Link capacitors for DC support, and absorption capacitors for voltage absorption.

On-board chargers: Applications of film capacitors include EMI filtering capacitors, DC-Link capacitors, output filtering capacitors, resonant capacitors, power factor correction (PFC), etc.

Charging piles: DC fast charging piles use high voltage and high power, requiring output filtering capacitors and DC-Link capacitors, among others.


(d) Continued increase in demand for film capacitors under high-voltage fast charging: The role of capacitors is energy storage and filtering, which can be used as automotive DC support capacitors to prevent damage to IGBTs caused by power changes. Previously, automotive capacitors were mainly aluminum electrolytic capacitors, but their rated voltage could not exceed 500V; Film capacitors have a rated voltage of over 1000V, strong high-voltage resistance, excellent frequency characteristics, high safety, wide temperature range, and are therefore suitable for 800V high-voltage trends. The main usage per vehicle is 1-2 units, with an average price of 200-300 yuan. For a 400V architecture, the unit value of film capacitors is about 400 yuan. With the upgrade to an 800V architecture, the unit value is expected to increase by another 20%.



5.Metal Soft Magnetic Powder Cores

(a) Overview of Magnetic Materials Electronic components are mainly divided into active components and passive components. Inductive components belong to passive components because they do not have any controlled source functions internally. Magnetic materials are core materials for manufacturing inductive components, and the quality of materials largely determines the performance of inductive components. Magnetic materials are divided into permanent magnets and soft magnets. Permanent magnets, also known as hard magnets, can retain their residual magnetism for a long time and withstand not very strong magnetic field interference. Soft magnetic materials correspond to them, are easy to magnetize and demagnetize, and their main function is to guide magnetic flux and convert electromagnetic energy, widely used in various electrical energy transformation devices.


(b) Introduction to Metal Soft Magnetic Powder Cores Metal soft magnetic powder cores are made by pressing magnetic powder coated with insulating materials and are the best-performing soft magnetic materials in the field of soft magnetic materials today. The comprehensive properties of soft magnetic materials, such as high saturation magnetic induction, low loss, high magnetic permeability, miniaturization, and corrosion resistance, are suitable for manufacturing key equipment or components such as 5G base stations, photovoltaic inverters, rail transit transformers, new energy vehicles and charging piles, large data center substations, and ultra-high voltage control cabinets.


(c) Application of Soft Magnetic Materials in New Energy Vehicles Soft magnetic materials are mainly used in three application areas of the new energy vehicle sector: charging piles, on-board AC/DC chargers, and on-board DC/DC converters. In addition, they are also used in other parts of vehicles such as keyless systems, audio speakers, and backup cameras.


(d)Continued increase in demand for soft magnetic materials under high-voltage fast charging Metal soft magnetic powder cores are mainly used in OBC inductors for pure electric vehicles, with a single vehicle usage of 0.7kg, and in boost inductors and OBC inductors for hybrid models, with a single vehicle usage of 3.3kg. Achieving an 800V high-voltage platform requires installing a boost inductor on the DC/DC converter, which will increase the single vehicle usage of pure electric vehicles from the original 0.7kg to about 2.7kg, an increase of about 300%. DC fast charging piles can also increase demand for metal soft magnetic powder cores. According to industry production data, the usage of metal soft magnetic powder cores is 0.1kg per kw. The penetration rate of high-voltage fast charging piles is gradually increasing. Conservatively assuming that due to technological upgrades, the future single consumption of metal soft magnetic powder cores will decrease from 0.1kg to 0.06kg per kw, then the usage of metal soft magnetic powder cores per charging pile will still increase significantly from the original 2kg to about 18kg.



Wiring Harnesses (Cables + Connectors)

(a) Overview Automotive wiring harnesses are the main network of automotive circuits and are the "blood vessels" of automobiles. A complete vehicle's wiring harness products cover engine wiring harnesses, dashboard wiring harnesses, body wiring harnesses, etc. Wiring harnesses mainly consist of three parts: cables, wrapping materials, and connectors (terminals), and are customized products. The core material of cables is copper, and the cost of copper materials constitutes the absolute majority of the cost of wiring harnesses.


(b) Trends in the development of wiring harnesses High-voltage wiring harnesses Drive for automotive intelligence, vehicle networking driving high-bandwidth wiring harnesses Requirements for vehicle lightweighting: Aluminum instead of copper


(c) Continued increase in demand for wiring harnesses under high-voltage fast charging: High-voltage wiring harnesses, due to their special operating characteristics, have high voltage, high sealing, high heat resistance, anti-interference, and high durability requirements. As the voltage increases to 800V, and the increase in charging power does not double, the current will be appropriately reduced. At this time, high voltage wiring harnesses with smaller cross-sections can be used to transmit electrical energy, resulting in reduced harness weight and volume. This leads to a decrease in resistance losses within the circuit, indirectly enhancing power density and energy utilization efficiency.


Currently, under existing technological architectures, each new energy vehicle requires 15-20 high-voltage connectors. With the upgrade from a 400V to an 800V platform, additional components such as high-power fast charging interfaces and high-to-low voltage converters (DC/DC) will be necessary. These new additions will require additional high-voltage connectors, leading to an increase in the usage of high-voltage connectors and consequently driving up the value of high-voltage wiring harnesses (cables + connectors) per vehicle.


In summary, these six key components - charging modules, on-board power supplies, distribution systems, film capacitors, metal soft magnetic powder cores, and wiring harnesses - are crucial for the operation and safety of charging piles, especially under the trend of high-voltage fast charging in the new energy vehicle industry. Their roles and demand are expected to continue evolving as the industry progresses towards higher efficiency, greater power, and increased integration of new technologies.

New industry Technology regarding to Bussmann fuse, ABB breakers, Amphenol connectors, HPS transformers, etc. 

TAG:   EV Charging  Fuse