Since the beginning of winter, the city has been attacked by cold current for many times, and the cooling range is rare in recent years. For a time, “cold” has become a hot topic in the society. The continuous cold weather not only makes the electric car drivers face the problem of excessive power consumption, but also makes the citizens who travel by electric bus feel chilly. From January 6 to January 14, the public service hotline 12345 frequently received feedback from the public that “some buses do not have air conditioning and heating, especially new energy trams”, “it’s too cold on the bus”
White smoke from passenger’s mask
On January 7, the observation station in the southern suburb of Beijing showed that the lowest temperature was – 19.6 ℃, breaking the record of Beijing’s lowest temperature since February 1966. On the West bus stop of Muxiyuan bridge, the passengers waiting in line are all “fully armed”, and the cold wave weather makes waiting a little painful. “Coming, coming car!” This cry in the crowd is more urgent than usual. The bus has become the pronoun of “Hope”, and everyone is looking forward to getting on the bus. No. 665 bus stops, but when passengers get into the carriage, they find that the inside of the bus is not much warmer than the outside. Under each other’s masks, white smoke is emitted as usual. Sitting passengers hold their shoulders and necks; standing passengers pull their hands into their sleeves and feel the armrest reluctantly.
“On such a cold day, why isn’t it warm in the bus?” According to the passenger’s question, the safety officer on the bus was also very helpless, “according to the requirements of epidemic prevention and control, the bus should open windows for ventilation while driving. We are also electric vehicles. We dare not turn on the air conditioner too much, for fear that the temperature is too low, and the electricity can’t be watched.” However, at the request of several old people, the driver still turned up the hot air of the air conditioner. After a while, there was a little hot air on the bus, but it didn’t last long. As the bus arrived at the station and the front and rear doors opened, the hot air also “got off” with the passengers.
It is understood that No. 665 bus is a pure electric vehicle, 26.77 km one-way. The driving route is from luhaiyuan bus station in Daxing District to the South Square of Beijing south station. The reporter noticed that the South Square of Beijing South Railway Station is not equipped with a charging pile. After route 665 arrives at the South Square of Beijing South Railway Station, it can’t be charged. It needs to turn back according to the original route and return to luhaiyuan bus station to be charged. Many new energy bus drivers told reporters that when they saw the percentage of electricity “Hua Hua” falling down, they had no bottom in their hearts. They were really afraid to walk half the way “lying on the ground”. The electricity consumption of air conditioning and heating was not small, so they did not dare to drive.
On January 11, the temperature picked up. The reporter took bus No. 665 again to see if the problem of driving range reduction is better under the weather environment of 0 ℃ or so, and whether the air conditioning and warm air dare to be turned on. It turns out, it’s still pretty bad.
“Look at my cotton padded jacket. It’s actually two layers, but it’s still cold. It’s so cold that my feet hurt.” The car’s security officer told reporters that in winter, no matter whether there is a cold wave or not, as long as the temperature is close to 0 ℃, the car’s air conditioning and warm air dare not turn up, for fear that the power is not enough.
Listening to the reporter talking about air conditioning and warm air with the security officer, a passenger also came to say that he would take bus No. 665 every day. In the cold winter, he was distressed to see the driver and security officer wearing three layers inside and three layers outside. “We got off at the station anyway. They were really hard-working. The driver sits for two or three hours, and the safety officer can only stomp on the car when he is cold. “
It’s the evening rush hour, when we catch up with the traffic jam or wait for the red light, sometimes other buses are parked side by side outside the window. The reporter can occasionally see several fuel buses, and it seems that we can feel the warmth through the window.
The car doesn’t warm and air conditioning. The batteries suck.
On January 11, the reporter came to Chongwenmen bus station, where there are No. 108, No. 111 buses, and No. 104 buses running in the surrounding Beijing station area. These buses are different from pure electric new energy vehicles. They belong to new energy trolleybus, which can be described as “double drive”. Will this kind of buses also encounter the problem of air conditioning hot air afraid to turn on?
At the bus station, the reporter saw that thick cotton padded clothes and a large pot of hot water are almost standard for all drivers. The driver who was preparing to leave told reporters that according to the requirements, the air conditioning and warm air on the car must be turned on, “but to tell you the truth, it doesn’t work very much. Sometimes when the display temperature is set to very high, the temperature in the car still can’t come up.”
At Beijing station, a No.104 bus is preparing to start. The driver told reporters that about one third of the distance of No.104 bus is driven by battery. In winter, in order to make the car warm and protect the passengers from the cold, he thought of many ways, but the effect was very little. In cold weather, the poor discharge ability of the battery is an unavoidable problem.
Liu Baolai, deputy manager of science and Technology Information Department of Beijing public transport group, told reporters that they are very concerned about the battery problem of new energy vehicles. Especially this winter, the cold wave and epidemic situation are superimposed to highlight the battery problem. Novel coronavirus pneumonia needs to be maintained in order to prevent and control the new crown pneumonia. However, the outdoor bus is ventilated, but the outside is very cold. The operation of the air conditioning brings more load to the battery. There are more than 8200 pure electric vehicles in Beijing public transport group. According to the degree of battery, the driving range is between 40km and 150km. From the actual situation, after the warm air is turned on in winter, the driving range of vehicles will decrease by about 30% – 50%. “For this reason, we require drivers to fully charge and then shut down their vehicles in case of special cold weather, so as to ensure that there will be no power loss in the next operation period. If necessary, we will increase the number of vehicles in operation. “
Liu Baolai said that the new energy vehicles for public transportation in Beijing have been gradually promoted since 2015. I believe that with the continuous improvement of battery technology, such problems will be gradually solved. According to the requirements of national environmental protection and new energy development policies at the present stage, the development of new energy vehicles for public transportation in Beijing during the “14th five year plan” period will still be dominated by electric drive and supplemented by hydrogen fuel vehicles. When purchasing and updating vehicles, Beijing Public Transport Group will focus on the climate characteristics of the operation area, adopt battery type with good low temperature characteristics, and adopt new battery heating technology to improve the vehicle’s all climate adaptability.
Dialogue with experts
How new energy buses cope with severe cold
In line with the concept of environmental protection, the development of new energy buses in Beijing maintains a vigorous momentum, but how to deal with the test of batteries in winter? The reporter interviewed Wang Jian, the chief science communication expert of public transport in China.
Reporter: what do you think of the “battery anxiety” of new energy buses?
Wang Jian: the problem that the working ability of material battery decreases at high or low temperature is determined by the material characteristics, which is an unavoidable physical law. This means that at the present stage, there are problems in the range of use of material batteries. For example, the use of new energy vehicles driven by materials and batteries in southern cities such as Shenzhen is relatively good, because the lowest temperature in winter in these cities is difficult to reach below 0 ℃, and the impact on batteries is much smaller than that in northern cities such as Beijing.
Reporter: what do you suggest Beijing do?
Wang Jian: there are three ways to realize the leap from traditional fuel vehicles to electric buses: the first is to develop trolley buses, the second is to use material battery vehicles, and the third is to use hydrogen fuel vehicles. These three ways have their own advantages and disadvantages. The implementation of trolley bus can achieve zero emission, but it should also be combined with the overall planning of the city. Not all areas are suitable for cable erection. Material cell is restricted by temperature, while hydrogen fuel is environmentally friendly, but its cost is relatively high. In the long run, through continuous technological innovation, the problem of material battery constrained by temperature can be gradually improved, and the cost of hydrogen fuel will continue to decline, which will become a major trend in the future.
According to the specific situation of Beijing, the path of diversified layout can be adopted, and the electrification of the above three ways can be used at the same time and adapted to local conditions. At present, with the development of material battery vehicles, the application of trolley buses can also be promoted simultaneously, which can be flexibly adjusted according to the urban planning, climate temperature, terrain characteristics and other conditions.
Editor in charge ajx