The development trend of 48V power supply


In addition to autonomous driving and electric vehicles, the hottest topic in the automotive field this year is the 48V power supply system, which is a low-cost fuel-saving technical solution. The system replaces the traditional 12V lead-acid battery with a 48V lithium ion battery with an energy of less than one kilowatt-hour. , Replace the traditional starter motor and generator with BSG motor, and add 48V/12V bidirectional DC-DC, battery management system and other devices.

In the past 60 years, the 12V power supply system has been used in automobiles worldwide. There are no doubts about the stability and safety. What is the reason for the transition from 12V to 48V in automotive power systems? I think we should start from two points:

First, automobile functions continue to increase. In addition to basic air conditioners, fans, wipers, and lights, many entertainment information systems have now been added. In the future, they will be further intelligent. The 12V power system cannot bear the ever-increasing burden of the engine.

Second, environmental protection regulations have become stricter. According to EU regulations, by 2020, fuel consumption will be reduced to 4L/100km and CO2 emissions will be as low as 95g/km. Satisfying this standard obviously cannot be accomplished by simply improving the fuel efficiency of the engine. Hybrid and pure electric vehicles are regarded as the best technical routes.

Therefore, in 2011, Audi, BMW, Daimler, Porsche, and Volkswagen jointly launched a 48V system to meet the increasing demand for on-board loads, and more importantly, to meet the strict emission regulations in 2020, and subsequently released 48V System specification LV148.

In view of the improvement of the 12V to 48V power supply system, the OEM and the solution provider still need to coordinate in many aspects. Some manufacturers have adopted a 12V/48V dual power supply system, in which the 12V power supply supplies power to the system with a small load current, such as audio, meters, and wipers. The 48V power supply supplies power to devices with relatively large load currents, such as air-conditioning, car lights, fans and other electrical systems.

Advantages and disadvantages of 48V power supply system:

The 48V power supply system has both advantages and disadvantages. The advantage is that it reduces carbon dioxide emissions, improves fuel efficiency, and adapts to future policies and regulations. Automakers can increase their costs by 30%, achieve a 50% to 70% increase, and can save 15% of fuel; improve driving power and improve Driving comfort: Compared with the high-voltage system, it reduces the difficulty of matching, reduces the weight and cost; increases the power load, improves the active and passive safety of the car, and provides power support for assisted driving, long-range and short-range radar, and ultrasonic sensor camera systems.

The disadvantage is that as the voltage rises, the electronic compatibility requirements increase; 48V voltage has potential arcing hazards, which need to be prevented in advance; migration from 12V to 48V requires redevelopment and testing, and the risk of long cycle is high; 48V is more expensive than 12V. High, energy-saving effect is not as good as high-pressure hybrid system.

Component manufacturers and vehicle manufacturers are taking action

The automotive market is a market with a large market share and rapid growth. The 48V power supply system includes batteries, DC/DC converters, fuses and battery controllers. A wide range of applications will surely drive the growth of automotive electronic components sales. Component suppliers have also seen this opportunity and have made efforts.

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