Electric vehicles have their own difficulties in winter.
When we are worried about the serious loss of heating in winter, some Tesla owners in North America have encountered a more serious problem - air conditioning failure. Since January this year, the Canadian transportation department has received a number of complaints, users said that their Tesla can not operate the air conditioner normally, especially in the cold environment of -10 ° C, the heat pump air conditioner is not heated, and the car is like an ice cellar.
On February 9, Tesla submitted a recall to NHTSA, for 26681 Teslas, it will solve the problem of heat pump air conditioning heat failure through OTA, which involves a variety of Model S/X/3/Y produced so far in 2021. The scope is not unique.
The colder it is, the less it works?
According to the complaint of Tesla owners, the failure of heat pump air conditioners mainly occurs in extremely cold weather, which tesla considers to be "inefficient range", and this situation is usually below -10 ° C.
There is even one owner who complained that he has encountered a heat pump air conditioning failure for two consecutive years, February 2021 is the whole month without blowing hot air, after replacing the manifold to solve the problem, this winter is another situation of heat failure.
Heat pump air conditioning is Tesla's "pride", how can it go wrong. Even if there is a failure, it is the fault of the software.
Therefore, in the recall document submitted by Tesla, it is written that some models of heat pump air conditioners failed, mainly because of the vulnerabilities brought about by them after a software upgrade in December 2021, resulting in the heat pump air conditioning valve has been open, the internal coolant of the evaporator can not flow, and finally the compressor automatically shuts down, and the car cannot heat up.
Driving in a low temperature environment for a long time is more likely to happen. In the complaints of some car owners, it is mentioned that their Tesla heat pump air conditioner failed, even in the case of -30 ° C outside the car temperature.
According to Tesla's explanation, the failure of the heat pump air conditioner only affects the heating in the car, and the defrost function of the front windshield is still working normally. However, this is not the case in fact, and the US "Consumer Report" mentioned that after some users fail the heat pump air conditioner, the defrost effect will also be affected, and the safety will be reduced. At the same time, the blower is still circulating the air normally, bringing air from outside the car into the car.
How bad the experience is, how fierce the user's complaints are. Tesla officials launched a software package on January 15, claiming that software vulnerabilities can be fixed and firmware upgrades can be carried out through OTA. Still, they launched a formal recall to address the potential risk of tens of thousands of Teslas.
It sounds very responsible and responsible, but this does not completely solve the user's concerns. Because, after Tesla began to mass-produce heat pump air conditioners at the end of 2020, it is not the first time that the chain has fallen in winter.
In March 2021, Tesla North America had a small-scale heat pump air conditioning maintenance treatment, the problem at that time was also cold weather heating failure, but different from this year's software bug, OTA solution, 2021 involved in the situation is caused by sensor failure, the need to replace 3 refrigerant pressure / temperature sensors.
At that time, some people questioned why Tesla, a Chinese-made Model Y that also uses heat pump air conditioners, was not included in the official maintenance? Could it be that winter temperatures in most parts of China are not low enough?
At that time, Tesla's response was that the version of the heat pump air conditioning sensor used in the two countries was different, and the first model Y in the Chinese market had a small range of heat pump air conditioning failures, noise and other issues, which were eventually considered to be small probability events and did not cause widespread concern.
Heat pump air conditioning, is it mythical?
Tesla is considered a new weather vane in the mainstream market when it applies heat pump air conditioning on a large scale in 2020.
Prior to this, the PTC heating method commonly used in the automotive industry made pure electric vehicles lose power in winter very seriously. A 500-kilometer electric vehicle with a range of 25 °C is set in a heating mode, and the actual endurance is only about half.
There has been such a survey, some taxi drivers in order to save electricity, only when carrying passengers will turn on the air conditioning heating, the rest of the time are with willpower to carry the freeze. Although pure electric vehicles have made great progress in terms of endurance and BMS in recent years, how to make air conditioners more energy-efficient and more power-efficient has always been a big problem to be solved.
Tesla's heat pump air conditioning can be said to be the most effective solution at present, through software control, to achieve heat pump, motor, PTC with heating, in the working environment of 10-30 ° C, Tesla heat pump air conditioning thermal efficiency ratio can do 5, is the same conditions PTC air conditioning 5 times.
Because of this, even if Tesla uses the standard endurance version of the lithium iron phosphate battery, the winter endurance shrinkage will not be too outrageous. In the winter test of new energy vehicles held by Chedi, models equipped with heat pump air conditioners consume 17.4 kilometers of electricity in half an hour, while PTC air conditioners need to consume 20.1 kilometers. The average actual mileage, the heat pump air conditioning model is also 29 kilometers more than the PTC model.
The energy-saving effect of heat pump air conditioning is obvious to all, but the disadvantages are also obvious.
The heating failure in the low temperature environment may only be the software and hardware design defects of Tesla's heat pump air conditioner. The more realistic problem is that the heat pump air conditioner cannot work effectively at -20 °C or lower temperatures.
The working principle of heat pump air conditioning is to use refrigerant to absorb heat from low temperatures, compress the steam through the compressor, and liquefy the condenser exothermicly, and this cycle process realizes heat handling.
However, when the temperature is too low, the handling efficiency of the heat pump air conditioner is actually not up to the conventional level, in the environment above 10 ° C, the thermal efficiency ratio of the heat pump air conditioner is the best, and the consumption of very little electrical energy can get more thermal energy; and at -20 ° C, the thermal efficiency ratio is only 1 or even lower, and the heating effect and stability are not as good as PTC.
Tesla believes that when the external ambient temperature and battery temperature are lower than -20 ° C, the heat pump air conditioner has no solution, so it uses a hybrid scheme, as long as the battery is heated to meet the working range of the heat pump air conditioner, and it can play a role.
However, tesla's current hybrid collaboration method is controlled by software, and the small replacement of parts in March 2021 and the recall in 2022 reflect the shortcomings of the new plan.
Heat pump + CTP, the same destination
Heat pump air conditioning, bringing the principle of household air conditioning heating to electric vehicles, the industry sees a more energy-efficient, smaller heating scheme. At present, a number of new cars launched by brands such as Xiaopeng and BYD have also added heat pump air conditioning as auxiliary heating equipment.
In the global market, heat pump air conditioning has become a new outlet, including Japan and South Korea Denso, Han Ang system, Europe's Bosch, MAHLE, Valeo and other automotive suppliers and air conditioning manufacturers have also joined the research and development of heat pump air conditioning. This is obviously the most balanced solution for pure electric vehicles to solve energy efficiency endurance and heating needs, and in Tesla's practice, heat pump air conditioning brings better mute effect, which is a necessary plus for the riding experience of pure electric vehicles.
However, heat pump air conditioning is not a low-cost technology, coupled with its relatively complex structure, as well as obvious working defects, it will not be widely used in the pure electric vehicle market. The industry estimates that the assembly rate of heat pump air conditioners in the entire electric vehicle market is only about 50%, and low-end family cars may not be able to enjoy this technology.
Based on this judgment, when bydy Dolphin, Roewe Ei5, GAC Aean V and other independent brand models also provide heat pump air conditioning, naturally let people feel some surprises. For example, the Roewe Ei5, which was the earliest taste in the domestic market, cost more than 10,000 yuan when it was equipped with heat pump air conditioning in the early days, and even though the price has now been significantly reduced, it is still much higher than PTC air conditioning.
We do not doubt the ability of independent brands to roll in the configuration, as well as the strength of Chinese parts suppliers for cost control, but behind the term "heat pump air conditioning", whether they really give the data and experience they should have.
Tesla is not the first person to eat crabs, BMW, Audi, Jaguar in the high-end market, Renault and Toyota in the mainstream market also have superheated air-conditioning solutions. However, Tesla is the first to apply heat pump air conditioning to a wide range in the global market, especially in the winter of 2021 and 2022, after experiencing the severe cold test of Northern Europe and North America, first of all, there were many failures and recalls in Canada, and the instability and immaturity of this technology were quickly exposed.
At the beginning, the cost of heat pump air conditioning was high, CTP air conditioning was the absolute mainstream, when the pure electric vehicle gradually moved from its temperature comfort zone to a higher latitude, the CTP power loss problem became more and more acute. Market demand has driven the technology research and development and cost control of heat pump air conditioners, and then Tesla has obtained a relatively balanced and compatible solution here. But it is also because of the dual demand for heating and battery life in cold areas, which once again poses a challenge to heat pump air conditioning.
How to make CTP air conditioners and heat pump air conditioners work together better? In the face of the inevitable trend of electric vehicles, solving the problem of refrigeration and heating will be the main issue of the industry for a long time to come.
Not long ago, Mercedes-Benz unveiled EQXX mentioned that solar energy to power air conditioners and other low-voltage systems, which is not a new solution, but we are curious about how Mercedes-Benz will make a former chicken rib function into an effective device.
Figure | Sourced from the web
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