INTRODUCTION

With the development of new energy vehicle battery technology becoming more and more mature, the battery life has been significantly improved, but the problem of slow charging still plagues the entire industry and has become an important factor hindering the rapid increase in the penetration rate of new energy vehicles. Traditional high-power fast charging piles have reached their limit with air-cooled technology. As a new trend in the evolution of charging technology, the safer, more efficient, and more economical liquid-cooled overcharging technology has become the focus of the industry.

1. Status and trend of charging pile industry

In recent years, new energy vehicle market has developed rapidly in our country, the number of vehicles has increased rapidly, and the demand for charging electric vehicles has increased significantly.

According to the statistics of Zhiyan Consulting, as of December 2022, the cumulative number of electric vehicle charging piles in the country is 5.21 million units, a year-on-year increase of nearly 100%. Among them, there are 1.797 million public piles, accounting for 34.5%; 3.413 million private piles, accounting for 65.5%. It is estimated that by 2025, the number of electric vehicle charging piles in China will reach 10 million. With the continuous improvement and upgrading of charging and cooling technology in the future, high-power liquid-cooled fast charging piles have obvious advantages over the existing air-cooled technology, and liquid cooling may become the mainstream trend.

At present, most of the civilian fast charging piles adopt air-cooling technology, and they all face the problem of rapid heating and high heat generation, which brings safety problems to high-power fast charging piles. In order to solve the pain points of industrial applications, high-power charging pile engineers thought of liquid cooling to cool down, the use of liquid-cooled high-power charging piles has two obvious advantages: first, the charging current is larger and the charging speed is faster. Second, the charging noise is smaller and the protection level is higher.

2. The principle and application of charging pile liquid cooling technology

The application of liquid cooling technology in super charging piles has become more and more common.

The liquid-cooled super charging pile is mainly composed of a charging module, a charging gun, a controller, a liquid cooling system, and a cabinet. In the liquid cooling system, the coolant is circulated through the water pump to key components such as the battery pack, charging module, charging gun, and controller, and the normal operation of the system is ensured by cooling these components.

The high-power liquid-cooled charging gun uses a pump to drive the flow of coolant. When the coolant passes through the liquid-cooled cable (the liquid-cooled cable will heat up when it is working due to carrying a large current), it will take away the power of the cable and the charging connector. The heat is returned to the fuel tank (stored coolant), and then driven by the pump to dissipate heat through the radiator and work in a cycle, which can meet the requirements of small cross-sectional area cables carrying large currents and low temperature rise.

The liquid cooling method can make the cooling liquid recycle, and the closed heat dissipation environment can ensure the cleanliness of the heat dissipation process while ensuring the heat dissipation efficiency. Compared with traditional air cooling, it has better heat dissipation effect and longer service life, so it is more and more favored by the market.

Application of micro liquid-cooled pump technology in super charging pile liquid cooled system

What pump is suitable for high-power liquid-cooled charging piles? High-power liquid-cooled super charging piles use liquid-cooled pumps to transport ethylene glycol aqueous solution or silicone oil media to cool down the heating components (cables, gun heads), with high cooling efficiency. The liquid-cooled pump in the liquid-cooled system is usually used for liquid circulation. The role is to transfer heat from the inside of the charging pile to the radiator. In the liquid-cooled system of charging piles, micro-water pumps are widely used in small charging piles and mobile charging equipment, and with the advantages of small size, low energy consumption, and low noise. Micro liquid cooling pumps are usually powered by DC power, and can also be used in combination with renewable energy technologies such as solar panels to achieve more energy-saving and environmentally friendly purposes.

As one of the core components of high-power liquid-cooled fast charging piles, the micro liquid-cooled pump is responsible for cooling medium flow transmission and pressure control. It is very important to choose a safe, reliable and efficient liquid-cooled pump. Usually, In the case of the same cooling medium, the cooling effect is better and faster when the delivery flow is large and the pressure is high compared to small flow and low pressure. Based on the above ideas, the selection of the pump mainly considers the flow rate, inlet and outlet pressure conditions, viscosity, At the same time, comprehensive factors such as inlet conditions, volume, energy consumption, noise, and voltage need to be considered. We will combine various types of pumps for horizontal and vertical comparative analysis with gear pumps.

1. Horizontal comparison The traditional pump types mainly include centrifugal pumps, diaphragm pumps, gear pumps, and vane pumps.

Centrifugal pumps belong to centrifugal kinetic energy pumps. The higher the characteristic head, the smaller the flow rate, which is generally not considered;

Some common centrifugal water pumps on the market also have the following deficiencies when they are applied to the charging pile liquid cooling system:

1. The flow and head are limited, and the scope of application is relatively narrow;

2. It is difficult to maintain and needs regular inspection and replacement;

3. Some micro pumps have a short lifespan and need to be replaced frequently.

The reciprocating diaphragm pump belongs to the plunger type volumetric pump. There existing pulse during the fluid delivery process, the temperature rise control is unstable, and it will be limited by the life of the diaphragm. As a rotor type volumetric pump, the gear pump has a history of hundreds of years from its invention to its use. It has a stable flow rate and is used in medium and high pressures. Traditional gear pumps are mainly used to transport lubricating media. The sliding vane pump belongs to the rotor type positive displacement pump, its performance is close to that of the gear pump, but the sliding vane is frictiing colse to the pump cylinder surface, it is easy to wear after a long time, and the abrasive particles will pollute the medium;

2. Vertical comparison of various micro magnetic gear pumps

Before understanding the micro gear pump, we must first understand PEEK, the core gear material of the micro magnetic gear pump. Since the birth of PEEK special engineering plastics, PEEK has been used in precision structural parts, seals, bearings, gears and other fields. With various modifications The development of additives (such as carbon fiber, molybdenum disulfide, glass fiber, tetrafluoroethylene, and ceramics) has derived various formulas of PEEK with different properties. Compared with pure PEEK, it has higher mechanical strength and better wear resistance. PEEK with ceramic fillers has a service life more than 5 times that of pure PEEK, and can be used in various harsh working conditions.

The micro gear pump is developed based on PEEK modification technology. The micro gear pump can operate under low viscosity or even no lubrication conditions. At the same time, it adopts the magnetic coupling design to achieve high pressure without leakage. Precision micro gear pumps are used in small flow, no pulse, high linearity, high pressure difference, no leakage, precision metering and other working conditions.

At present, various miniature magnetic gear pump technical routes of domestic and foreign manufacturers are mainly through PEEK gear shaft material modification and breakthrough in processing technology direction, PEEK sliding bearing material and processing technology direction breakthrough, and micro magnetic gear pump structural design direction improvement. Years of research and experience in miniature magnetic gear pumps tell us that if the overall design direction is wrong, the accuracy, performance and life of the pump will be greatly reduced.

1. Material modification of PEEK gear shaft and breakthrough in processing technology

The gear shaft material is divided into two parts, one is the gear part, and the other is the shaft part.

The first solution: Traditional European and American gear pumps (and some domestic gear pump manufacturers), the gear material is mainly made of ordinary PEEK filled carbon fiber, the shaft is made of SS316L material, and it is used in occasions with small loads. It is processed by hobbing after injection molding into a cylinder. PEEK filled carbon fiber is easy to process, and the machining accuracy is good, but the shaft made of 316L material is relatively soft. After running for about 5-6 months, the shaft will get thiner and thiner, and the gears will run out and wear seriously, until the pump body and gears are worn out, and it can’t be see during short-term use.

Traditional PEEK+ stainless steel shaft shaft surface wear situration

The second option: The gear material is made of imported PEEK high-strength wear-resistant material, and the shaft is made of zirconia nano-ceramic material. Due to the difficulty of PEEK machining, many of them are formed by one-time injection molding of the tooth shape. The injection molding is easily deformed by the injection temperature.The consistency of each batch of gears processing is poor, which affects the flow rate, the production cost is low.

The third solution: the gear shaft of JONSN precision micro gear pump, the gear is made of high-strength wear-resistant PEEK material imported from the UK, the shaft is made of zirconia nano-ceramic material, and the gear is finished by precision CNC rolling. Through improving the coating of the tool material, and strict control of tool processing time, it solves the problem of imported high-strength wear-resistant PEEK gear processing. At the same time, the tooth shape is shaped by several hours of high-temperature molding heat treatment. The gear has high precision, stable size, smooth surface, high consistency, and long service life. The disadvantages are: High cost, it is suitable for heavy-duty high-precision occasions.

Breakthrough in the direction of PEEK sliding bearing materials and processing technology.

The traditional bearing material is mainly made of ordinary PEEK filled carbon fiber material, which is easy to process, has weak wear resistance and load-bearing performance, it can only be used in light-load conditions.

JONSN precision grade miniature gear pump sliding bearing, made of special modified PEEK-based composite nanoscale ceramic formula, made of special processing and molding technology, high strength, strong resistance to dry wear, used in heavy-duty occasions, life up to 20,000 more than hours.

3. Improvement of the structural design direction of the micro magnetic gear pump

The structural design of the traditional micro gear pump has continued the American design (three-stage structure + PTFE diaphragm seal design) more than 20 years ago. The gap between the two ends of the gear is easily affected by the thickness of the gasket, resulting in large internal leakage and poor delivery accuracy. Inefficient, the structure is as follows:

The structural design of JONSN micro gear pump adopts (integrated structure + static sealing ring design picture as follows), and its advantages are as follows: 

(1) The rear pump body and the gear cavity are integrated into one body, and the whole is completed by CNC at one time, which reduces the number of fixture replacements, and the gear shaft assembly accuracy is high.

(2) Reduce the number of sealing rings and reduce the number of leakage points;

(3) The gaps between the gear and the cavity are completely guaranteed by machining accuracy, with high matching precision and high consistency, and there is no need for manual grinding and repair of the gear and cavity. The more human intervention, the worse the consistency;

(4) The internal structure adopts a large-diameter flow channel design to reduce fluid movement resistance and ensure high transmission efficiency;

(5) Flexible connection configuration

Installation type

Type 1 Left in right out

Type 2 Down in up out

Type 3 Up in down out

Type 4 Top in top out(customize)

Type 5 Side in side out(customize)

After analyzing the structural principle and process of the pump horizontally and vertically, let’s analyze the motor. The quality of the motor directly affects the overall life. The advantages of JONSN matching motors are as follows:

(1) It adopts shielded structure with small size.

(2) A DC 24V/150W shielded brushless motor was developed for the high-power charging pile liquid cooling system. The pump body + motor assembly length is only 99mm, small size and high torque. The coil stator is made of fully automatic winding, and the winding orderly rows. See picture as follows:

(3) The motor can work continuously for a long time under high and low temperature environment.

JONSN precision micro magnetic gear pump adopts car-grade brushless motor driver, and the magnetic rotor adopts high-temperature NdFeB strong magnetism, which can adapt to long-term continuous work at ambient temperatures from -40°C to 70°C. The driver comes with over-temperature protection and over-current protection functions.

4. JONSN-MRV Liquid Cooling Charging Pile Liquid Cooling Technology Solution

With a deeper understanding of the JONSN precision micro magnetic gear pump, we return to the specific application of the charging pile liquid cooling system. Take the overcharging system application working condition of DC high voltage charging power above 350KW as an example, the cooling medium is silicone oil medium, viscosity 10mPa.s, flow rate 4-6L/min, pressure 4bar, DC 24V power supply, power ≤150W, effective running time 25000 hours.

MRV220SZKL-TV 150W DC 24V shielded brushless motor

Through the micro gear pump selection system developed by JONSN, the selection parameters are as follows:

Founded in 2010, JONSN is a company deeply involved in the R&D, production and sales of gear pumps. Since the establishment of Jonsn company, we have clearly put forward the business philosophy of " Focus on making each gear pump attentively". Jonsn has a gear pump assembly line, as well as gear hobbling machine, gear grinding machine, surface grinding machines, CNC machine tools, machining centers and all around comprehensive testing, and experiment equipments, etc.  

Due to the changes in internal & external markets since 2019, Shanghai Jonsn Fluid Equipment Co., Ltd. made a new plan which was establishing new factory in the central region. Benefit from Ganzhou high-efficiency business environment and Ganzhou gear industry processing ability, the new factory was officially located in Ganzhou National Economic Technological Development Zone. Our factory has passed German TUV Rheinland ISO9001-2005 quality management system certification, China CCS, France BV, American ABS, Japan NK and other classification societies, and has obtained a number of patented technologies. The company has an excellent R&D and innovation team, cooperates with foreign companies, relies on our rich experience in the field of gear pumps for many years, through innovating technology, adopting new processes and new materials, optimizing the internal structure of the pump, and improving the gear pump. The quality and technical level of the pump have made major breakthroughs in a number of key technical fields of precision gear pumps. JONSN gear pumps have become key control equipment pumping delivery in many high-end manufacturing industries.

JONSN is an early micro-pump company that entered the field of charging pile liquid cooling applications in China. It occupies a large market share in the field of charging pile liquid cooling water pumps, and has a professional and mature solution for fast charging pile liquid cooling.

(1) Customized service. JONSN is a gear pump manufacturer with independent technology research and development and production capacity, owns a professional R&D team, technical support team, and after-sales service team. We can specially customize the gear pump according to the needs of the customer's system, as well as the performance parameters such as flow rate and head, and different motor types can be provided.

(2) Small size and low noise. JONSN strictly controls the noise and space occupied by gear pumps, and its small size and silent design will not cause noise disturbance to the surrounding environment and users.

(3) Reliable quality. Fast charging piles usually need to complete the charging task in a short time,meanwhile they need to run stably for a long time. Therefore, it is necessary to choose a reliable micro gear pump to reduce the impact on the power supply of the charging pile. JONSN strictly controls the quality of each gear pump manufactured, and each gear pump has to undergo multiple tests and quality inspections before leaving the factory to ensure the reliable quality of the gear pump.

The precision micro pump produced by JONSN Fluid Technology Co., Ltd. makes up for the shortcomings of ordinary water pumps in the industry. It can be accurately applied to high-power liquid-cooled fast charging piles. At the same time, it can guarantee product quality, product delivery time, pre-sale professional selection, and after-sale technical support. It is an ideal choice for high-power liquid-cooled fast charging pile liquid-cooled water pumps.

JONSN Marketing department(Original)