High-efficiency Air Compressor
Screw Air Compressor (working principle) :
Screw compressor is a volumetric gas compression machine with working volume for rotary motion. The compression of gas depends on the change of volume, and the change of volume is achieved by the rotary motion of a pair of rotors in the housing of the compressor. Basic structure: in the body of the compressor, a pair of helical rotors are arranged in parallel to each other. Usually, the rotor with convex teeth outside the section circle is called the Yang rotor or Yang screw. The rotor with concave teeth in the section circle is called Yin rotor or Yin screw, a Yang rotor is connected with the prime mover, driven by the Yang rotor Yin rotor rotor rotation on the last pair of bearings to achieve axial positioning, and bear the axial force in the compressor. Cylindrical roller bearings at both ends of the rotor enable the rotor to achieve radial positioning and withstand radial forces in the compressor. At both ends of the compressor body, a certain shape and size of the orifice are respectively opened. One for inhalation, called the air inlet; The other is used for exhaust, called exhaust port.
Product advantages:
1. Screw Air Compressor works smoothly, has small vibration and low noise compared with piston machine.
2, oil and gas separator: filter material, high efficiency, air oil content rate is less than 2ppm.
3, controller: operation and related data are displayed on the control panel, easy and convenient operation.
4, spraying lubricating oil with sealing, cooling, noise reduction and lubrication.
5, high stability, high efficiency, small vibration, low noise advantages.
6. Good heat dissipation system. Adopting plate-fin structure and material, the cooler has high pressure resistance, high heat dissipation efficiency and good corrosion resistance.
7, Air Filter: heavy duty, multi-stage air filter, large working face.
High-Efficiency Air Compressor,High Efficiency Compressor,High Efficiency Rotary Compressor,High Output Air Compressors Yangzhou Mustang Air Compressor Co. , Ltd , https://www.aircompressor-ym.com
At this year's battery forum of the electric car hundred people's power, everyone is enthusiastically discussing how to achieve the goal of the magnificent car power lithium battery: for example, the car's power distribution should be 80 kWh or even 100 kWh, and the cruising range is 500. Kilometers, such as charging for 400 kilometers in 15 minutes, such as PACK does not exceed 800 yuan per kilowatt hour, the battery core is 600 yuan and so on.
On the one hand, all lithium battery manufacturers follow the OEM, and they are blindfolded on the road of high energy density, fast charge and high safety. Under the stimulation of the energy density and mileage of the subsidy policy, the life of various pure electric vehicles is 150 kilometers, 260 kilometers and 380 kilometers, all the way up. On the other hand, at the same time, in the economic short-haul market represented by low-speed electric vehicles, when they began to upgrade the power system under the dual pressure of product upgrade and standard, they found that finding a suitable lithium battery system is not An easy task.
Long driving mileage and fast charging are the development direction of electric vehicles, but must we go 500 kilometers, 600 kilometers, 700 kilometers? In low-speed urban conditions, if you commute 30 kilometers a day, the car is loaded with a 300-kilometer battery pack. This configuration makes the system energy inefficient and uneconomical.
In response to this problem, the founder of CATL, Zeng Yiqun, proposed the way of marketization of power batteries, namely: launching different platform products for different needs of market segments -
Special road-right market: For example, the BEV market under the limited purchase of Beijing and Shanghai, users expect to completely replace the fuel car, requiring long battery life and fast charging.
Economic market: Meet daily short-distance travel, requiring low price and basic safety performance.
Operational market: Highly reliable battery, high cycle life, high cost performance, no need for fast charging.
Performance market: Saobao type, the pursuit of the ultimate products, such as Tesla, EP9 super run.
Under the requirements of relevant national technical standards, the lithium electrification process of low-speed electric vehicles suddenly accelerates. This is a market that currently has more production and sales than new energy vehicles and has great potential to be explored. So how can current lithium battery manufacturers better integrate with the product characteristics of low-speed electric vehicles and cut into this market?
This article will take an example of a typical 330 model product in the industry for analysis.
A 330 model, the whole preparation quality is 849kg, equipped with 6 12v100AH ​​maintenance-free lead-acid batteries, motor power 5kw. The maintenance-free lead-acid battery has a specific energy of about 34 wh/kg and a cost of about 580 yuan/kWh.
1. Energy density selection
Lead-acid version: The weight of the battery is about 210kg, which accounts for 25% of the weight of the whole vehicle.
According to the specific requirements of the battery energy density in the 2017 subsidy policy: the mass energy density of the pure electric passenger car power battery system is not less than 90Wh/kg, and the subsidy is 1.1 times higher than 120Wh/kg.
In terms of lithium iron phosphate, most of the current battery system energy density levels in the market are around 70 wh / kg -80 wh / kg, 90 wh / kg enterprises easily reach the standard, 120 wh / kg to work hard. In terms of ternary lithium batteries, 90 wh/kg has been exceeded, and there are not many enterprises that achieve 120 wh/kg.
The energy density is one level, and the safety of the battery is also difficult to ensure. Low-speed vehicles have neither subsidies nor excessive mileage. The standard weight of 800kg is also easy to achieve, and the energy density of 80-90 wh/kg is sufficient. Cost > Energy Density.
Lithium-ion version: The battery system weighs about 80kg, which accounts for 11% of the total vehicle weight.
2. Charging characteristics
Charging characteristics of current major customer groups of low-speed electric vehicles:
First, generally accept slow charging, lead-acid battery charging time is about 8-10 hours;
Second, there is no charging pile, using household 220v system charging;
Third, most customers use during the day and charge at night.
Fast charging required for high-speed cars requires improved power performance, and efforts are required in all aspects of the battery, including the positive electrode, the negative electrode, the electrolyte, the diaphragm, and the structural design. Large current charging will cause the Joule heating effect to be aggravated (Q=I2Rt), and bring a series of problems such as material side reaction decomposition and gas production in the battery, and the risk factor suddenly increases.
For the low-speed electric vehicle's lithium battery system, basically do not consider fast charging, 0.5C charging, 3-5 hours, enough to meet customer needs. Cost > Energy Density.
3. Voltage selection
According to the "GB-T18384.3-2001 electric vehicle safety requirements Part 3: personnel electric shock protection" provisions: the working voltage is lower than 60V, is a Class A voltage circuit, does not require protection against electric shock.
The existing low-speed electric vehicle products mainly have 48V, 60V, and 72V operating voltages, and the voltage is controlled below 60v. Compared with high-speed vehicles, the cost of the high-voltage system can be saved.
4. Discharge performance
The 330 model has an instantaneous maximum current of 300A. During normal driving, the current is about 60-90A. Choose a 18650 battery that is common in the market. The specifications are as follows:
Set the power system to 60v 120AH, that is, the battery cells are connected in parallel 60 times, and then 16 groups are connected in series. It can be seen that the continuous discharge current and the maximum instantaneous discharge current meet the requirements. According to the parameter characteristics of low-speed electric vehicles, the cost can be prioritized and the performance of ordinary batteries can be selected.
5. Temperature management
The market of low-speed electric vehicles has obvious regional characteristics, and Shandong Henan accounts for about 60% of sales.
The annual average temperature in Shandong Province is around 13 °C. In January, the lowest temperature in the province is generally around -3 °C; most of the other regions are at -2.0 to -1.0 °C. The average annual temperature in Henan Province is 12.8~15.5 °C. The whole winter is cold in the province, and the average temperature in the coldest month (January) is around 0 °C. Low temperature performance requirements for batteries are relatively low.
For low-speed electric vehicles:
Cost > low temperature performance improvement
Cost>system fever management
6. Cycle life
The longer the cycle life, the better? According to the product characteristics, comprehensive settings, to meet the needs is the best:
Low-speed electric car consumers, in addition to a part of taxis to pull passengers, delivery, the largest proportion is the daily travel. According to the information released by the first electric network, the mileage of consumers in one month is 90.8% less than 1000 kilometers. Through this picture, you can see that there are more people with a monthly mileage of around 300 kilometers. Very few in more than 1,000 kilometers, almost no more than 2,000 kilometers. The market's mainstream products have a cruising range of 80-120km, which also confirms this statistic.
According to the above data, 1000km per month, 35km per day, 12000km per year. The battery is charged for 100km, and the battery is charged once every 2 days, that is, 180 cycles a year. In the automobile market, the average turnover period of Chinese people is 5 years. According to the 5-year cycle, the total mileage is about 60,000 kilometers.
If you want to ensure that the battery system is used for 5 years, the number of cycles required is 900. The lead-acid battery should be replaced at least once in 300-500 cycles. At present, the theoretical number of cycles of ordinary lithium battery system is 1500, and the actual number of cycles after grouping is between 500 and 700 times. To ensure the economics of the whole life cycle, you need to jump and reach 900 times. .
7. Cost setting
The 330 product, the lead-acid battery price is about 4,200 yuan, accounting for about 19% of the total vehicle cost. If the two-year cycle is exchanged according to the 5-year cycle, the price of the lithium-ion system is about 8,400 yuan, that is, 1,200 yuan/degree, which can be balanced.
Current electric vehicle power system price information: Prabhakar Patil, CEO of LG Chemical Power Battery Division, said, "The battery cost of most electric vehicles is about $400/kWh, Tesla is $240/KWh.", according to ASEC Most of the public information given by Matsushita is between $350 and $400/kWh, or $2,380/kWh.
The estimated downward trend in costs for countries:
The International Energy Agency (IEA) and the US Department of Energy also predict that battery costs will be below $200/KWh by 2020. The 2025 manufacturing plan released by the Ministry of Industry and Information Technology in 2016 has positioned the battery cost at 0.8 yuan/Wh. If calculated according to this standard, a typical low-speed lithium battery system is about 5,760 yuan, which is lower than the two sets of lead-acid prices of the same capacity, which has an absolute economic advantage.
8. Overview
The traditional high-speed pure electric passenger car has high energy density and fast charging requirements, and is a high temperature + high voltage system with high risk factor. Therefore, the battery system will include: battery + cooling / heating components + high voltage components + low voltage components + structural components + battery management system.
Low-speed electric vehicles, if using a system below 60v, can be greatly simplified to battery + low-voltage components + structural parts + battery management system. And with only 16 sets of series modules, the battery management system can also be simplified for specific purposes.
The design considerations for the lithium battery system of low-speed electric vehicles are arranged according to the weights as follows:
The number of cycles is not less than 900> the cost is less than 1.2 yuan / wh> basic safety> low temperature performance> energy density> charging time.
Low-speed electric vehicles are purely market-oriented products. There are no subsidies, how to integrate with the market, and to ensure economic and competitiveness. Lithium-ion manufacturers that want to enter this market must study. The current annual output of low-speed electric vehicles is about 600,000 units. If the growth rate is normal at next year, it is expected to reach 1 million units, calculated according to the average of 7 kWh per unit, totaling 7 million kwh, which is about 10 billion yuan. If we can balance the above factors, we will be able to do a good job in the market and promote the low-speed electric vehicle industry.
At present, the battery manufacturers supporting high-speed vehicles, on the one hand, due to the inertia of thinking and the lack of attention, on the other hand, because of the different requirements of the main products, in the battery materials, equipment, technology, technical routes, design methods, etc., Not suitable for low-speed lithium battery. Then, this brand-new market will be upgraded by 3C manufacturers, or it will be redefined by high-speed power battery companies. Finally, we can see who can adapt to the market faster, who can more closely match the characteristics of low-speed cars. Hehe.