Shulou(Shulou.com)11/24 Report--

Respondents:

Vehicle control team

Power battery team

Thermal management team

Energy management team

Author: sun Wei

Introduction:

Entering winter, the "big test" of new energy vehicles is coming. Especially in the north, the attenuation of pure electric battery life has become one of the biggest headaches for users. We have also received some user feedback, hoping to optimize the ideal L series of pure battery life rate in winter.

A few days ago, the ideal L-series models launched a new strategy through OTA 4.6.2, as well as a new air-conditioning energy-saving model, with open source and cost-saving measures in parallel to comprehensively improve the performance of pure electric battery life in winter.

Many users have posted new achievements: after the OTA upgrade, the battery life has indeed increased!

Let's see how the engineers do it.

Open source: identify users' typical operating conditions and optimize energy management strategies

Endurance attenuation in winter has always been a difficult problem for new energy vehicles. Some users may think that there is a gap between the actual mileage and the official figures claimed by the car companies, which is the "false mark of battery life". But in fact, there are many factors that determine the mileage of a vehicle in winter.

"the current power battery will inevitably have the problem of discharge attenuation under the condition of low temperature in winter; when the outdoor temperature is low in winter, the demand for heating inside the car increases, and the air conditioner has to work continuously to be heated by cold air, which leads to a substantial increase in power consumption of the air conditioner; the lower the temperature, the higher the air density, the greater the wind resistance and the higher energy consumption; rubber tires will harden at low temperature, resulting in an increase in driving resistance In the electric drive system, the viscosity of the oil lubricated by the reducer gear will increase as the temperature decreases. All these constitute the reasons for the decline of the battery life of electric vehicles in winter. " The whole vehicle energy management engineer, Brother Chuan, introduced.

Under the same performance index of the industry, under the technical framework of non-heat pump air conditioning, the ideal L9's range retention rate has been ranked in the leading position, but we still take the initiative to identify a typical scenario of users' cars-many users only drive to and from work 20 kilometers to and from work every day, and the range under commuting conditions decays more severely than under low-temperature continuous driving conditions. This is because in winter, after users get on the bus twice a day, the air conditioner will turn on heating and high energy consumption. At this time, the battery will also have lower power due to low temperature. In order to ensure the power at low temperature, the range expander will intervene in advance, which leads to the shortening of pure electric life.

"the goal of battery life is the responsibility of our vehicle performance department. when users have a request, we will look at the user's car scenarios and problems encountered to see what happened? is there an opportunity for optimization? then join with various professional departments to analyze and disassemble and formulate optimization strategies and actions." Brother Chuan said.

Some users are used to the smooth acceleration of a pure streetcar at room temperature. when entering the low temperature season, he will most likely ask: "Why is this car so fleshy in winter?" the sense of "meat" comes from the fact that when the temperature is low, the discharge ability of the battery will decline, that is, the so-called "the power of the car becomes worse", which is the characteristic of the battery.

"if users are accustomed to overtaking at high speed or driving in a state of strong power, and the power becomes very poor at low temperature, the user experience will not only be bad, but may also lead to accidents." Jin Ming, an engineer for vehicle control requirements, said.

Reviewing from the ideal ONE to the ideal L series, we have been exploring whether the battery power can be mentioned again. "in terms of hardware, compared with conventional ternary batteries in the market, we have optimized the design of cell materials and improved power performance at low power levels." Wang Jian, an engineer for battery performance research and development, said that we analyzed the user's driving habits and the actual ability of the battery, including that the user's foot oil usually accelerates the battery for a few seconds and the battery performance under intense operating conditions, and then carries out more stringent development and verification of the battery in line with the user's use scene, so as to continuously enhance the discharge capacity of the battery.

There are three kinds of energy modes for an ideal car, namely, pure electricity priority, fuel priority and fuel-electric hybrid. In pure power priority mode, when the battery charge is less than 20%, the extender will start and maintain the battery at about 20%. The pure power priority mode also has a forced pure electricity option, and when the power is turned on, the extender will intervene to work when the power is reduced to 3%, allowing users to maximize the use of electricity and reduce fuel consumption.

This time, we have also optimized the battery power usage strategy, which can be adaptively adjusted according to the real-time situation of each user to maximize the battery capacity.

"these promotion schemes are quite special and we don't have many cases to refer to." Wang Jian said that for this promotion plan, the battery team carried out more than five months of development and verification. User needs and usage scenarios have always been the guidelines for battery improvement-the same battery can provide users with a better experience according to the iterative strategy of scene matching.

Jin Ming is responsible for the range augmentation strategy of the ideal L car series, that is, when the battery power is detected to weaken during winter driving, which can not meet the basic driving requirements, the range extender will start to replenish the power of the vehicle.

This part of the optimization should be based on the real needs of users and use scenarios, redefine new dynamic indicators. " We need to see what the average speed of the user is and what the maximum speed is, and we also need to observe their daily average driving situation, predict the next power demand of the user, and release this part of the power in advance, so that each subsystem is in a better standby state, and the dynamic response will be faster. For different models, there are differences in performance indicators, absolutely not across the board. For example, if you use forced pure electricity under urban conditions, users may not have so high requirements for power performance, and we should consider more about comfort. "

The brand-new pure electric battery life optimization strategy of ideal L series models in winter can effectively improve the discharge performance of power batteries at outdoor temperatures of ≤ 20 ℃. On the premise of ensuring the power, delay the intervention time of the extender, so that the user can get a longer pure electric mileage.

Consumption reduction: new air-conditioning energy-saving mode, further reducing energy consumption

As the saying goes, "dressing indiscriminately in February and August" refers to the alternation of seasons, and there are many changes in temperature and humidity during the day, especially with the changes in the weather and personnel in the car, the fluctuation of cold and heat in the car is more obvious, and the needs of users to use air conditioning are more diverse. "users sometimes need dehumidification and sometimes need heating. In order to better control comfort and temperature, most of the time the compressor cools and PTC heats. This will result in greater energy consumption. " Zhen Nan, an engineer for the development of vehicle thermal management system, said that energy saving and consumption reduction of air conditioners have been going on.

At the beginning of the year, we have done a round of optimization through OTA to reduce the starting range of the compressor and try to avoid unnecessary cooling and heating at the same time. The ideal L series also has the function of automatically turning off the air conditioner without people in the second row, which can further save energy.

In general, in order to prevent fog in winter, traditional cars will adopt the pure external circulation full fresh air mode, but because the outdoor air is very cold, it must be heated to 30 or 40 degrees before blowing into the car, which will consume a lot of energy. Thanks to the good hardware foundation of the ideal L car system, we are the first to adopt a dual-motor circulation throttle on the L9 and L8, which can adjust the proportion of internal and external circulation. "such a part of fresh air can ensure fresh air in the car, but also prevent fog, and the other part of the internal circulation air can greatly reduce energy consumption." According to Zhennan, the circulating throttle of the dual motor has another advantage, which avoids the cold air blowing into the car without passing through the heating core when the speed is high.

The ideal L7 has also evolved into a double-flow air conditioner. To put it simply, the air conditioner will intelligently use the fresh and refreshing air of the outer circulation to blow the occupant's head and glass position, and the relatively warmer inner circulation air to blow the feet.

Many users may not have noticed that there is a temperature and humidity sensor on the front windshield of the ideal L series. "there is a big temperature difference between inside and outside the car in winter, and people will exhale moisture in the car, so it is easy to fog. The lower the outdoor environment temperature, the higher the speed, the more likely it is to fog. It is responsible for detecting humidity changes in the car and further controlling the proportion of internal and external circulation wind better."

This time OTA has further added a new air-conditioning energy-saving mode, which will significantly reduce the energy consumption compared with the previous normal mode. In this mode, the vehicle will automatically adjust the air conditioning output power and the rising / cooling speed, and at the same time automatically adjust the seat heating and steering wheel heating, so as to improve the air conditioning energy consumption in winter while maintaining the temperature comfort in the car. Reduce energy consumption and increase vehicle available pure electricity mileage.

Another key task of Zhennan is the waste heat utilization of the augmenter, which can effectively improve battery activity, reduce power waste and attenuation, and improve battery life.

The ideal ONE already has the waste heat utilization function of the extender, and on this basis, the L series increases the waste heat utilization of the motor, which can ensure that the battery can be heated at the initial stage of pure electric mode and extended range mode.

The waste heat utilization of the motor is mainly to transfer the waste heat generated by the motor and controller to the battery package for heating. The difficulty lies in the ingenious design of the two water loops, upgrading the proportional three-way valve originally used for cooling and heating switching to the proportional four-way valve, and connecting the water circuit of the motor and the battery in parallel, compared with the series waste heat utilization, the pipeline is simpler and easier to arrange. On the other hand, after the car starts to drive, the motor itself needs to dissipate heat, and the heat is dissipated into the air through the radiator. In order to make use of this part of the heat, we add a temperature control valve to the motor circuit, which is retained through a small cycle at low temperature to keep the battery warm.

Through the verification of the real car forced pure electric mode, after OTA 4.6.2, the ideal L9 turns on the air conditioning energy-saving mode below 0 ℃ outdoor, the attenuation of urban commuter service in winter is obviously alleviated, and the actual pure electric mileage can be greatly increased.

OTA: better products, evolution never stops

Ideal car monthly OTA upgrade speed and efficiency, even in the new power brand, are very rare. Haibo, a vehicle control requirements engineer, said: "many enterprises regard OTA as a way to solve BUG, and tend to sew and mend, solve problems and loopholes. But the direction of our OTA work is different. We are constantly providing users with new features, greatly improving the performance of existing features, constantly testing growth boundaries, and refreshing better products for users."

"for traditional car companies, after the car comes on the market, it means that the research and development work is over, only to assist in solving some problems. And what about us? After the launch of the product, research and development has not been over, has been through OTA to improve the performance of the vehicle. When we go out to do the three-high experiment, we will meet colleagues or friends who will make fun of: are you still working on your cars that are already on the market? Yes, in the models that have been on the market, we are still willing to invest a lot of development and verification energy to constantly improve it and enhance its product power. "

Jin Ming, who has many years of experience working for a new energy vehicle consulting company, believes that the greatest advantage of ideal cars is that they attach great importance to and respond quickly to user feedback. "We can really proceed from the needs of users, and there are never simple and rough decisions that are taken for granted or relatively simple."

Let the product continue to grow based on user feedback and demand, we always adhere to the work philosophy, Chuango recalled, "starting from the ideal ONE, we heard more user feedback is that they want to reduce fuel consumption in winter, and very few users complain about short battery life. Ideal L9 in winter battery life is far better than the ideal ONE, but received more user feedback, saying that they want to increase pure electric battery life, we will also be curious, why?"

Through user research, it is found that since the ideal car first used large batteries in Zengji new energy vehicles, users have become accustomed to the mode of urban electricity and long-distance fuel. in urban road conditions, users want to use more pure electricity to drive. In addition, the comfortable "mobile home" makes more scenes of electricity consumption, and many users are willing to have fun or rest in the state of parking, in which users do not want the add-on to start, noisy and emitting, and not environmentally friendly.

"in my opinion, users' higher demand for pure electricity is not a complaint, but a new expectation to us." Brother Chuan said.

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