Electric vehicles have their own terminology—some are colloquial, some are technical—which can be mysterious and confusing to unfamiliar people. Understanding the meaning of these terms is not only the key to deciding whether an electric car is right for you, but also the key to deciding which electric car is right for you. For example, do you care how fast your car receives gasoline from the pump? No, but you need to know how quickly your car and home can replenish the battery to use the home to charge, and there is no standard answer. However, we can help you learn more by understanding the terms related to charging in the EV glossary of Cars.com.
Alternating Current (AC) Alternator Ampere Battery Pack Battery Module Combined Charging System (CCS) Charger Direct Current (DC) Direct Current Fast Charging Destination Charging Resistance Coefficient (Cd) EVSEfrunkinverterJ1772 Kilowatt (kW) Kilowatt-hour (kWh) Level 1, 2, 3mpg-erangerion motor Supercharges
In alternating current, electrons regularly reverse direction. The relevance of alternating current in the field of electric vehicles is that all batteries require direct current (DC), where electrons always flow in the same direction, so whenever the vehicle is charged, the alternating current must be converted or rectified into direct current.
In Level 1 and Level 2 charging, a component called the charging module hidden in each EV is responsible for this task and controls the charging rate. In public DC fast charging, the charger is external and directly provides DC power to the car battery, bypassing the on-board charging module as the current blocking point. The DC fast charger starts at a voltage almost twice the household voltage, and rectifies the AC power from the outside using components that are larger than the car can accommodate. These are two reasons why DC charging is much faster than Level 2.
Alternating current gets its name because the current changes direction. In the United States, it changes 60 times per second. It is difficult to understand what this even means. When you dig deeper and understand that when the current is reversed, it is technically more confusing. From positive to negative in the same conductor. However, alternating current has advantages over direct current, such as the smallest loss during long-distance transmission, and the possibility of using a transformer to increase or decrease its voltage. The irony is that most electric vehicles use AC drive motors, so yes, the battery’s DC power must be converted back to AC power again. This process is called inversion to propel the vehicle. In fact, hybrid vehicles usually use AC motors, which means that the current is actually continuously converted from AC to DC or back. Every time these conversions occur, whether in or outside the car, there will be a related energy loss.
Traditional gasoline and diesel-powered vehicles use belt-driven alternators, or alternators, even though all power requirements are direct current.
In all traditional modern cars, a gasoline or diesel engine uses a belt to drive an alternator to generate electricity, charge the starter battery, and power the lights, electronics, and other electrical components on the car. Nowadays, virtually all of these devices require direct current, which makes the type of generators that only produce alternating current seem strange, but alternating current generators are the preferred generators because they are smaller, lighter, and more durable than direct current generators – The three craziest standards for automakers. This has been roughly the case since the 1960s, when solid-state rectification (conversion of alternating current to direct current) became feasible. The alternator contains such rectifiers and voltage regulators to ensure that the DC voltage is correct.
Level 2 means 240 volts, but the amount of electricity delivered to the car also depends on the current, which varies greatly between level 2 chargers. Using the classic pipe analogy to compare the current passing through the wire, the voltage represents the pressure that forces water through the pipe, and the current is the rate of water flow mainly determined by the diameter of the pipe. To get more water from the end of the pipe, you can increase the pressure or pipe diameter. The same is true for electricity: increase the voltage or current (amperage) to get more power (in watts) at the other end of the wire. Unlike pipes, larger diameter wires have less resistance and allow more current to flow.
An ampere is the unit of measurement for the electrical service that a household can allocate from the power company-for example, 50, 100, or 200 amperes-and the current that a given circuit or level 2 charger can pass.
Regardless of the type, the batteries in the battery pack are usually grouped into modules, which increases the structure and simplifies the replacement of failed batteries. The battery pack includes a battery management system that can track the charging status of the battery pack and monitor battery voltage and temperature. The kit contains its own fuse and a method of manually disconnecting it from the rest of the vehicle for maintenance. Contactors (heavy load relay switches) usually exist, especially in pure battery power systems. If the battery fails the on-board safety test or detects a collision, it is used to isolate the battery from the vehicle.
Battery electric vehicles rely on circulating fluid to manage battery temperature, except for the Nissan Leaf (shown in the picture), which does not have active thermal management. In most of these battery packs, there are channels through which the coolant (usually a mixture of water and traditional antifreeze) flows out of the battery, in a simple radiator or a heat exchanger connected to an air conditioner or heat pump. Adjusting the circuit.
Like any other standalone battery, these batteries are only suitable for a few volts. (What we call a battery with a higher voltage, such as a 12-volt car battery, is itself a collection of individual batteries in a housing—in this case, six batteries.) Lithium-ion batteries are divided into three basic types, namely Say three shapes: cylindrical, prismatic and bag-shaped. The cylindrical batteries that power some electric cars look so much like something that can be placed in a flashlight, so much so that you might think they are not complicated. Critics have said a lot about their packaging efficiency because their shape leaves space between the two, but Tesla seems to have performed well with this type for most of its history, despite the The brand is now dabbling in prismatic batteries, which are shaped like a deck card or candy. The style chosen by most other electric car manufacturers is the pouch, which looks like an almost empty polyester film Ziploc sandwich bag. Unlike the other two styles, the structure of the floppy disk bag depends on the battery module.
Because the voltage of battery cells is measured in low single digits, electric vehicles use tens to hundreds of battery cells, grouped in the case of providing structure (especially important for soft-pack batteries) and simplifying wiring. Each module usually has its own voltage and temperature sensors, and regardless of the number of internally connected batteries, there are only two terminals, depending on the manufacturer’s design. Typically, the module includes isolated channels through which coolant flows to manage the thermal state of the battery pack.
In the early days, electric vehicles purchased in Japan relied on a separate connector called CHAdeMO for DC fast charging, but now, most new electric vehicles with this function (except Tesla with its own connector) provide this composite CCS port . When searching for public charging options online or through apps, the owners of these cars must select J1772 for level 2 charging and CCS for DC fast charging.
For direct current, electrons flow in one direction. The main relevance in the world of electric vehicles is that electricity is transmitted on the grid in the form of alternating current (AC), so any time a car battery is charged, the alternating current must be converted or rectified to direct current. For level 1 and level 2 charging, the car itself achieves this through an invisible component called the on-board charging module. The DC fast charger starts at almost twice the household voltage, and uses bulky components that are usually hidden outside the charging area to rectify the AC power from the outside, and then feeds the DC power directly into the car battery, bypassing its on-board charging module. The blocking point of the current.
Although some electric vehicles use DC drive motors, most use AC motors, which means that the vehicle must convert the battery’s DC power to AC power to accelerate-and return it again during regenerative braking. Both rectification and inversion (the name of DC-AC conversion) can cause inefficiency, but automakers who choose AC motors are considering the overall performance and efficiency of the vehicle, not just a component or process. In terms of its value, even traditional vehicles rely on alternating current through the use of an alternator, which is a generator that generates alternating current, even though the entire vehicle is flooded with direct current.
Due to the existence of electric vehicles today, DC fast charging is best suited for occasional charging in a short period of time (for example, when traveling long distances or when the cruising range is insufficient). As the name implies, it is “fast”, but beginners of electric vehicles will not think that DC charging is faster than filling up the gas tank, and it can provide hundreds of miles of range in a few minutes. Automakers’ DC fast charging claims usually involve a 30-minute session, but this rarely represents a full charge. Although more and more automakers are offering some free DC fast charging when buying new electric vehicles, almost everyone admits that frequent fast charging will damage the life of vehicle battery packs. When there is a cost, fast charging is more expensive than public level 2 charging and is usually sufficient to eliminate the cost advantage of electric vehicles and home charging.
Both DC fast chargers and the three-phase AC power they require make them too expensive for home installations. They provide a power range of 24 to 350 kW, but there is no guarantee that EVs will be charged at this rate regardless of their own acceptance specifications.
Popularized by Tesla, the term “destination charging” aims to distinguish between slower away-from-home charging and DC fast charging (or super charging, in Teslaspeak).
The more stylish appearance of current vehicles reflects the aerodynamic movement that began decades ago, partly to improve fuel efficiency. Resistance is no different from a stuck parking brake or any other form of resistance, which hinders the effort of the engine or drive motor. The higher the drag coefficient of a vehicle, the more difficult it is for its engine to work and the more fuel it uses, whether it is gasoline, diesel or electricity.
The drag coefficient of a vehicle is not only affected by its size and shape, but also by its bottom surface and ground clearance. Vehicles on the ground tend to be more aerodynamic, which is why modern vehicles with active suspension are usually designed to automatically lower themselves on the highway. There is no doubt that the most efficient vehicles on the market-usually hybrid and electric cars-are hatchbacks, because the high rear is inherently more aerodynamic than traditional sedans or coupes. The top line dropped sharply. Car designers work in the wind tunnel, trying to reduce future models by one percent. After designing as much of the overall shape as possible, the engineers turned their attention to the airflow around the wheels, entering and passing through the engine compartment, with active grille shutters and past exterior door handles, which are increasingly Many places are flush with the side of the body. Side-view mirrors are a long-standing goal. If they are not required by federal and state regulations to use rear-view mirrors by name, they will be replaced by cameras.
EVSE is what we usually call an electric vehicle charger, whether it’s the included trickle charger cable or a more robust level 2 device you might install in your home or find it at a public “destination” charging station. The reason for the different names is that in electronic products, the name charger is technically reserved for components that manage battery charging and convert alternating current to direct current when necessary. EVSE does not do these things. Every car has a car charger that you can’t see to fill these roles. EVSE is mainly a safety device that can protect you and your vehicle from injury. It only contains a ground fault circuit breaker, some switches and circuits, which can communicate the power it can provide to the EV.
Whether it is a J1772 or a Tesla connector, 240 volts need to be held in your hand, especially when you are outside when it is raining. Before the connector is connected to the EV, the EVSE will not provide high voltage to the cable. After plugging in, the car can detect the EVSE pilot signal, which indicates how much power it can provide. Then charging can begin, and the EVSE will trigger a heavy-duty switch (called a contactor) to supply power to the cable. You can usually hear the click of this contactor. Similarly, if you want to remove the connector from the EV, the moment you press the release button, both the car and EVSE will turn off charging, so there is no danger.
Like the name itself, frunks tend to please and satisfy people. They can add versatility to the vehicle, but they are not always an advantage. We remind shoppers not to ignore the overall cargo capacity of the vehicle. For example, according to Cars.com’s measurement, Volkswagen ID.4 without a trunk provides more cubic feet of storage space behind the rear seat than its rival Ford Mustang Mach-E, when its trunk and trunk capacity are combined Time.
Inverter is a key component in electric vehicles and most hybrid vehicles, because most of the motors used in both vehicles are alternating current, and the battery is always direct current, so it must be converted by a traction inverter. The name is because its only task is to create AC power to power AC traction motors. Because Ford uses this technology in its Pro Power Onboard option, which powers the 120 and 240 volt sockets on the bed of the 2021 F-150 hybrid car (and the following F-150 Lightning electric car), the inverter The term also proliferated. The system can provide AC power from the hybrid battery pack alone, but a low battery state will cause the hybrid truck’s engine to start. Pro Power Onboard recalled the so-called inverter generator, which is similar to a standby generator that generates alternating current, rectifies it into direct current, and then inverts it back to alternating current. This may seem silly, but it is this redundant conversion that allows the inverter generator to run the engine at variable speeds depending on the load-a more efficient and quieter method-leaving the production of AC power to the electronics . In contrast, traditional generators are actually alternators, and they must run at a constant speed (essentially full speed and maximum output) to maintain a consistent 60 Hz AC cycle.
J1772 is not a good name for one of the two ubiquitous connectors on American electric cars and chargers (the other is a proprietary Tesla connector), but if you are in Google Maps Enter “Electric Vehicle Charging Station” or use any charging station finder app. Technically speaking, J1772 is only suitable for level 1 and level 2 charging. J1772 forms the basis of the combined charging system connector, which adds two conductors below it for DC fast charging. (This allows EVs with DC charging capabilities to have a composite charging port instead of two separate charging ports, as was the case with early Japanese electric vehicles equipped with CHAdeMO DC ports.)
Ironically, the more complex version of the J1772 connector got a simpler name, CCS. But there is nothing better than the name CHAdeMO.
Watt is the root unit, but we use kilowatts because when discussing electric cars instead of light bulbs, we always deal with quantities over 1,000. Kilowatts are important because they are the final product of a unit of electricity-the product of voltage and current. Therefore, when you talk about kilowatts, you don’t have to be as confused about variables as you do with other units. For example, level 2 chargers have a voltage of 240 volts, but unless you know their current rating (in amperes), you will not know how many kilowatts are provided for an electric car.
Although we are accustomed to using horsepower to measure the rated power of an internal combustion engine, fundamentally, kilowatts is also a rated power, because it has a built-in time component (1 watt = 1 joule per second), so each can be Convert to other. (In fact, both horsepower and watts are the products of the 18th-century Scottish inventor James Watt.) Although it is not common, electricity and internal combustion power are now combined in the same car, and engine readings are sometimes expressed in kilowatts for consistency.
In the final analysis, 1 kWh is the energy required for operation, for example, a space heater that consumes 1 kW in one hour. Or the power consumed by a 6 kW motor in 10 minutes. Although it is easy to conclude that an electric car with a 70 kWh battery will increase the electricity bill by 70 kWh each time it is charged, it is not that simple. On the one hand, there is always a loss when charging-energy is lost in the form of heat in the circuit, especially when the car converts the alternating current from the grid to direct current and recharges the battery. On the other hand, you usually don’t charge a completely dead battery-and most electric cars and plug-in hybrids don’t use their full battery capacity as advertised; this is the total (total capacity) Or net (usable capacity) measures the difference between battery ratings. One of the keys to keeping batteries healthy is not to fully charge or discharge them. The onboard software is programmed to manage them. Even if the battery level display of your EV shows that it is fully charged or empty, there may be unregistered buffers above or below.
We released a detailed explanation of the fee levels, mainly because we disagree with them. Level 1 represents trickle charging, which is of little use to pure electric EV owners. Level 2 indicates that this is a single thing, in fact it can mean fully charging the car in a few hours…or it takes all night to do so. Level 3 does not exist technically, but DC fast charging does exist.
The EPA’s mpg-e rating is not very useful when comparing the efficiency of plug-in vehicles with the efficiency of internal combustion engine vehicles, because it does not take into account the cost difference between the two fuel types. But it is great for comparing one battery electric vehicle with another, and it is better than nothing for plug-in hybrid electric vehicles (PHEV). maybe.
Carefully read the EPA’s ratings of new and old electric vehicles, and you may notice that efficiency has always been the advantage of Tesla models compared to similar competitors. It is easy to assume that any vehicle that is plugged into a power source must be efficient, but this is not the case. In a plug-in car, higher efficiency means longer range for a given battery capacity and an increase in the same charging time. Longer cruising range.
We are not too keen on the EPA’s method of rating PHEVs because the mpg-e rating combines electricity and natural gas. This means that there are already two variables, and for the purpose of calculating the rating, the distance traveled by the pair is any third. Suffice it to say that the PHEV should be rated for its mpg-e in pure electric mode, rather than combining a high electric mpg-e rating with a low hybrid mpg rating, so as to meet the official EPA regulations at some point in the journey, but here It may be higher before or lower afterwards, depending on the electric range of the vehicle-this is another variable.
The mileage of a plug-in vehicle is always an estimate, whether it is a manufacturer’s statement, an EPA estimate, or the remaining distance displayed on the vehicle’s dashboard. The same is true for gasoline-powered cars, as are many of the following points, but for the rich range and fast refueling represented by liquid fossil fuels, it has never been so important, so we have never paid attention to it before. Some electric vehicles do a better job than other electric vehicles in showing the variability of mileage and how to exceed or fall below mileage estimates based on conditions and driver behavior.
Aggressive driving, high speeds and the use of accessories (such as lights, especially cabin climate control devices) will reduce the mileage, but the impact of weather is the most significant: smooth roads will affect the mileage to a certain extent, but cold temperatures The biggest damage to battery capacity and swallowing is the electric cabin heating juice. An AAA study showed that when comparing the average EV of 20 degrees Fahrenheit to 70 degrees Fahrenheit, the distance loss was about 40%. (It helps to warm up or cool the cabin while it is still plugged in.)
Electric car shoppers in cold climates need to consider this effect and two other important factors: They may charge at home every night, and they should focus on the mileage per day instead of “per tank”, which is normal over time Over time, electric vehicles will lose some range, just like any other rechargeable device. Experts believe that by the end of the car’s warranty period (usually 8 to 10 years or 100,000 miles), the amount is about 20%.
Regenerative braking is often referred to as recycling by German automakers. Since GM EV-1 (calculated based on actual products), regenerative braking has always been a sign of the efficiency of EVs and hybrids, and its effectiveness only follows more sophisticated computers. Control and increase, this is the core of regeneration. Fortunately, regenerative braking has also improved the driver’s feeling, but it is rarely as linear and satisfactory as traditional hydraulic brakes, usually accompanied by a mushy feel on the brake pedal. One of the challenges engineers face is to provide a smooth transition between regenerative braking and traditional braking when regeneration reaches its limit (such as in harder braking), and traditional brake pads or brake shoes must interact with the brake disc or The brake drum is engaged.
One of the main advantages of regenerative braking is that it is frictionless, which means that the brake pads and brake shoes have a longer service life and require less frequent replacement than traditional cars. Another benefit is that the level of regeneration, and the intensity of the braking when you raise the throttle, can be adjusted, and many electric vehicles now offer at least a few settings-although some electric vehicles have temporary weird paddle trigger patterns. The strongest trend is single-pedal driving, that is, the accelerator brake is pressed hard enough to trigger the brake lights-this makes the brake pedal itself only need full-threshold braking during an emergency stop.
Due to regeneration, a more powerful (faster) EV can also become a relatively efficient performance vehicle, which is different from its gasoline-powered vehicle. Understandably, a larger and more powerful drive system will increase weight, which will damage efficiency, but in electric vehicles, a more powerful drive motor also represents a higher capacity regenerative generator, so at least it can restore some efficiency.
Although the term is borrowed from the world of internal combustion engines, Supercharge has begun to represent DC fast charging for Tesla car owners. The Supercharger network is the most mature fast charging network in the United States, with sophisticated automatic payment functions. Competitors are trying to catch up with it through the Pay & Charge standard. Although it has always been a unique resource for Tesla, CEO Elon Musk said on Twitter in July 2021 that the network will be open to other brands before the end of the year.
Although the term technically represents any type of electric motor that drives a vehicle, in today’s automobiles, traction motors already refer to electric motors. It seems unnecessary to designate an electric motor in a vehicle as a driving motor, but not all electric motors (even in a power system) drive the wheels, at least not directly. Some electric motors or motor generators are part of a hybrid power system, but are not primarily responsible for powering the wheels. Similarly, mild hybrid vehicles use belt alternator starters (also known as starter generators), which can contribute to the vehicle’s propulsion, but the term traction motor is usually reserved for larger (or largest) motors or direct The motor that powers the wheels.
For such a generally accepted term, voltage is a mystery-partly because there are no other specifications, such as amperage, which does not always make sense. Therefore, we will try to eliminate some common confusion about electric vehicles and voltage in the charging world. First of all, when you see a reference to 120 volts household voltage, it is the same as 110 volts, 115 volts, or whatever voltage you grew up with. The voltage in your home is the nominal specification, which means it can be higher or lower than 120 volts without any consequences, depending on how much electricity your utility company generates and how much electricity you and your neighbors are consuming. The same is true for 240 volts and 220 volts. We use higher numbers because this is how manufacturers specify the charging time for their vehicles. If we say 220 volts and they actually use 240 volts (faster), we will give them credit for nothing.
One of our biggest concerns about EV technology is that the charging name Level 2 represents 240 volts, but voltage is only one factor-pressure-and in American homes, it is the maximum. Therefore, if the pressure is constant, there is still a problem with current or flow, in amperes, to determine the power available at the end of the line (in kilowatts). The ampere ratings of level 2 chargers vary greatly.
As far as car batteries are concerned, the familiar starter battery has a rated voltage of 12 volts (although a healthy battery has a rated voltage of more than 13 volts, you can take the “nominal” battery home). Mild hybrids are usually 48 volts, full hybrids average about 200 volts, and 400 volts has always been a common nominal rating for pure electric vehicles, although some manufacturers have begun to double it. Brands such as Porsche, Hyundai and Kia said that this is mainly for faster DC charging, which requires a higher voltage public charger. Whether such devices can be downgraded to 400-volt electric vehicle charging remains to be determined.
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Post time: Aug-26-2021