Low temperature is one of the natural enemies of batteries, which has become an important factor restricting the endurance of pure electric vehicles. When the low temperature meets the air conditioner, the already stretched endurance is even worse. In order to reduce the impact of winter air conditioning on battery life, auto companies have opened their minds and have launched heat pump air conditioners.
However, relying solely on heat pump air conditioning can not completely solve the problem, so Cadillac LYRIQ further launched the "BEV Heat Efficient Integrated Thermal Management System" (hereinafter referred to as BEV Heat), proposing the concept of "dual heat source".
Air conditioning, pure electric car owners heartache
In the early days of pure electric popularization, consumers focused a lot on endurance, three-electric safety, attenuation, etc., and paid little attention to air conditioning energy consumption, and car companies were the same. To this end, the early pure electric early equipped with PTC air conditioners, such as Buick Micro Blue 6, Xiaopeng P7, Weilai ES6.
The working principle of PTC air conditioner is to use the resistance wire to heat up, convert electrical energy into heat energy, and warm the battery and crew compartment. Can be simply electric heater. This type of air conditioner has the advantages of simple structure, high safety and low cost, but the disadvantage is that the power is large and the efficiency is not high.
In order to ensure a rapid increase in cockpit temperature, car companies need to configure a higher power PTC heating module, a medium and large pure electric SUV front and rear heating power can reach 9.2 kilowatts. Even if the temperature rises to a constant, the PTC air conditioner only needs 2 kilowatts to keep the temperature constant, and the power consumption cannot be ignored.
Overseas media have tested the tesla Model 3 with PTC air conditioning for long battery life, and the results show that the energy consumption of turning on air conditioning and seat heating is 35% more than when turning off, and the cruising range is nearly 100 kilometers less. According to the normal power consumption in winter, 100 kilometers is equivalent to consuming 20 kWh of battery capacity.
Low temperature has seriously affected the endurance, PTC air conditioning makes pure electric vehicles more overwhelmed, causing consumers to complain, forming the impression that pure electric vehicles have a short winter endurance and fast power loss in winter. In the long run, pure electric vehicles themselves can not be left alone, let alone compete head-on with fuel vehicles.
Heat pump air conditioning, new option
Due to the performance of PTC air conditioner crotch pulling, car companies began to look for new air conditioners, and heat pump air conditioners stood out. Tesla announced that it will be equipped with heat pump air conditioners in all models in the future, and Tesla CEO Elon Musk has also taken advantage of popular heat pump air conditioners on social media.
Like Tesla, Cadillac also featured heat pump air conditioning on the first pure electric SUV, the LYRIQ; unlike Tesla, cadillac LYRIQ uses a more versatile design, more reliable parts, and more sophisticated algorithms, bringing performance and maintenance advantages.
However, heat pump air conditioning is not a new thing, daily life can be seen everywhere, air conditioning, refrigerator is the most typical example. Heat pump air conditioning uses the transformation of the medium under different forms, the medium is converted from liquid to gaseous to absorb heat, the gas is guided from the outdoor to the indoor, and the compressor is used to compress it into a liquid state and release heat, thereby realizing the handling of heat.
Compared with PTC air conditioning, the advantage of heat pump air conditioning is higher heating efficiency and excellent body feeling, and the disadvantage is higher cost. PTC air conditioners can completely convert electrical energy into heat energy, and the efficiency can reach 100%, but the heat pump air conditioner itself does not generate heat, only carries heat, so the efficiency can reach a staggering 300%.
Although the use of heat pump air conditioning will increase the cost by 30%-50%, if the high energy consumption of PTC is solved by increasing the battery, the cost will increase by 150-450%. In contrast, heat pump air conditioners are very affordable.
However, heat pump air conditioning is not as versatile as PTC air conditioning, because the work depends on the medium, in very low temperature conditions, the medium will freeze or other conditions can not work. This is also one of the main reasons why early heat pump air conditioning could not be popularized on pure electric vehicles.
Fortunately, the current technology can already make the heat pump air conditioner work in an environment of -20 °C, Cadillac LYRIQ through research to achieve -10 °C without frost risk, within 2 minutes the air outlet temperature reached 45 °C performance.
Cadillac LYRIQ, came a little different
Pure electric vehicles challenge the winter performance of fuel vehicles, which is very difficult. Fuel vehicles carry far more energy than pure electric vehicles, and even if the thermal efficiency of the 40% internal combustion engine, there are nearly 70% of the heat wasted. Fuel vehicles only need to use this wasted heat to meet the heating needs in winter and will not increase fuel consumption.
In contrast, pure electric vehicles are not so stupid, but Cadillac still wants to use the heat that may be wasted, after all, for pure electric vehicles, every bit of heat is precious, less loss is more gain. As a result, Cadillac LYRIQ targets the heat generated by the operation of batteries, motors and electrical systems.
To this end, Cadillac LYRIQ designed a waste heat collection system using battery coolant. At 0 °C, the motor heat is collected, the power can reach 2.5 kilowatts, the power can reach 1.9 kilowatts of electrical circuit heat, and the total power can reach 3.8 kilowatts when calculating the loss, which greatly relieves the pressure of the heat pump air conditioning, even in the cold of -8 °C, the power of such a system can reach 3.5 kilowatts.
Through the waste heat collection system, the heat of the battery, motor, and electrical system is stored in the battery coolant, and heat exchanged with the air conditioning refrigerant to warm the crew compartment. This means that Cadillac LYRIQ needs to establish a new "water heat source" on the basis of the "air heat source" of the heat pump air conditioner, forming a "double heat source".
The data shows that only the use of heat pump air conditioning can save 17% of energy, the design of dual heat source can save up to 83% of heat, even if the heat pump air conditioner is turned off, only the waste heat collection system can be retained, and 49% of energy can be saved.
Using the heat stored in battery coolant, Cadillac LYRIQ has introduced a Pre-Condition pretreatment function to help users alleviate the anxiety of air conditioning battery life in winter.
In the case of connecting the charging pile, cadillac BEV Heat will take power from the charging pile as much as possible, preheat the cockpit in advance, minimize the high energy consumption stage when the heat pump air conditioner is started, and increase the battery life.
If the user sets the departure time through the APP or the car machine, the pretreatment mode will also use the charging pile power to heat the cockpit temperature to the appropriate, store enough energy in the battery system and the hot circuit, and preheat the battery to the most suitable range of 25 ° C to maintain the strongest performance.
According to cadillac LYRIQ official data, this part of the heat can meet the daily commute of 1-2 hours, close to 50 kilometers of heating needs, so that daily driving does not consume cruising range at all.
In addition, low temperatures can also affect the fast charge of the battery. If the battery is not preheated, the pure electric vehicle heats the battery at the initial stage of connecting the charging pile to increase the rate. Cadillac LYRIQ BEV Heat can make users choose to book a charging pile on the map, that is, preheat the battery in advance, greatly reducing the charging time.
With BEV Heat, users no longer have to worry about low night temperatures affecting the battery. Cadillac's thermal management system combines the thermal insulation technology between the battery cell and the module, and the battery cell can still maintain a temperature of 5 to 10 °C for 12 hours in an environment of -7 °C.
The improvement of the "double heat source" greatly solves the impact of low-temperature air conditioning heating on battery life and alleviates anxiety, but to some extent, it is the pursuit of the ultimate energy, the pursuit of not wasting a little energy for the purpose of improving the efficiency and use experience of the whole vehicle as much as possible. Cadillac's BEV Heat system actually takes the low-temperature endurance competition to a new level.
Figure | Sourced from the web
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