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How Does a Lithium-ion Battery Work?

Lithium-ion batteries power the lives of millions of people each day. From laptops and cell phones to hybrids and electric cars, this technology is growing in popularity due to its light weight, high energy density, and ability to recharge.

So how does it work?

This animation walks you through the process.

Animation created by Sarah Harman and Charles Joyner

The Basics

A battery is made up of an anode, cathode, separator, electrolyte, and two current collectors (positive and negative). The anode and cathode store the lithium. The electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive current collector.  The electrical current then flows from the current collector through a device being powered (cell phone, computer, etc.) to the negative current collector. The separator blocks the flow of electrons inside the battery.

Charge/Discharge

While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other. When plugging in the device, the opposite happens: Lithium ions are released by the cathode and received by the anode.

Energy Density vs. Power Density

The two most common concepts associated with batteries are energy density and power density. Energy density is measured in watt-hours per kilogram (Wh/kg) and is the amount of energy the battery can store with respect to its mass. Power density is measured in watts per kilogram (W/kg) and is the amount of power that can be generated by the battery with respect to its mass. To draw a clearer picture, think of draining a pool. Energy density is similar to the size of the pool, while power density is comparable to draining the pool as quickly as possible. 

The Vehicle Technologies Office works on increasing the energy density of batteries, while reducing the cost, and maintaining an acceptable power density. For more information on VTO’s battery-related projects, please visit www.vehicles.energy.gov

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Debunking Myths About Electric Vehicles

 

 

This video is full of misinformation about electric vehicles. Read about the debunked myths below.

Myth #1: Electric cars are more toxic to humans than other cars. 

They based this claim on a study which has been debunked for inflating their emission estimates by 40% by accounting for battery replacement without recycling and adding the need for a replacement gasoline car with the EV.

Myth #2: EV batteries are made from rare Earth materials. 

In the video they claim that batteries are made from rare metals like lithium, cobalt, and cerium. Another claim they make is that the materials come from overseas from countries with a lot of pollution like China and the Republic of the Congo. There are many different battery chemistries using different minerals. They are not all the same nor do they have the same impact. Most battery makers try to avoid all rare earth metals.

Myth #3: Batteries always end up in landfills and are toxic. 

This is completely false. Battery recycling is expected to become a big business in the near future. Many automakers are making less energy dense batteries, using old batteries for energy storage, and recycling the minearls in old batteries to make completely new batteries. 

Article orignally posted on Electrek.

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Extending Your EV Range

Via fleetcarma.com 
Posted by Eric Schaal

For electric vehicles to catch on in the mainstream, consumers have to be comfortable they can handle everything a gas-powered vehicle can. Among other things, that means driving in extreme temperatures. No matter how hot or cold it gets, an EV must maintain its performance on a reasonable scale and keep occupants comfortable. Otherwise, plug-ins will remain a niche segment.

In fairness, the earliest electric cars were not capable of enduring an intense cold spell. Models without thermal management or advanced climate options burned battery power when there wasn’t much to begin with. Furthermore, drivers who weren’t used to EV technology may not have been prepared for handling these models in winter.

Of course, drivers of gas-powered cars also deal with range loss and other issues in the cold, though they are not as magnified. But getting the most out of an EV in winter takes effort, especially when a car’s range is below 100 miles. Here are steps drivers can take to maximize an electric car’s battery life during winter.

Climate Control

Nissan Leaf Climate ControlsSince EVs do not have the manufactured heat of a combustion engine, drivers must find creative ways to stay warm or otherwise sacrifice battery power. Actually, electric cars do not waste the type of energy gas-powered cars do (as heat), so greater efficiency is the source of the problem.

EV drivers have several methods for reducing battery consumption:

  • Heating before you unplug. Cold temperatures make a plug-in climate system work hard to warm a car, so there is no point wasting that energy after you stop charging. Before leaving on a trip during winter, heat the car before disconnecting from the power source.
  • Heated seats. Your car’s power system uses less energy to heat a seat than it would sending warm air into the cabin. Most EVs come with heated seats or offer the option, so consumers living in cold areas should take advantage of them.
  • Layered clothing. The easiest way to conserve battery power is using little to no heat. Always dress in layers when heading out in winter so you can stay warm whether or not the climate control system helps. A scarf, hat and driving gloves complete winter attire in an EV.

 

Parking & Charging

Nissan Leaf parked and chargingBecause a battery can lose range simply sitting in subzero temperatures, drivers have to consider where to park their cars when the weather is frigid. The same applies to charging, which can take longer when it’s cold outside.

Though it may be impossible for drivers without a garage, EV owners can try the following:

  • Parking in an enclosed space. Even public garages with openings on every level are better for retaining battery power than an open-air parking lot. EV owners might try saving charging for overnight in a garage, if possible.
  • Heated garages. Homeowners with a heated garage are in the best shape when it comes to retaining battery power and limiting energy waste. Mild temperatures allow for faster charging as well.

 

Driving

Tesla Model S driving

There are some aspects of winter that can’t be adjusted. For example, the density of cold air creates more drag for a car to power through, limiting an EVs range. However, you can change some aspects of the drive to make a battery hold its charge.

  • Steady pacing. Driving in the cold is often an uncomfortable experience, and it can lead to drivers rushing to a destination. Hurrying – accelerating too quickly and speeding in general – is a guaranteed way to drain your battery.
  • Inflating your tires to the proper pressure level ensures you will get better performance from the car, so check on them frequently during winter. Cold weather changes pressure levels much more than milder temperatures.
  • Remove unneeded accessories. Roof racks and other addons alter the aerodynamics of any vehicle, which in turn creates a heavier load for the powertrain to support. Unless you are using this type of equipment for every trip, consider taking it down for a bit.

 

Best EVs for Cold Weather Climates

Red Chevrolet Volt Driving

As with any vehicle purchase, plug-in enthusiasts should choose the model that suits specific driving needs. In the most frigid conditions, a plug-in hybrid may be the only option if you have to drive long distances on a daily basis, unless you are thinking of a high-end model.

Cold-weather EV choices should take the following into account:

  • Electric cars lose range as the battery ages. If you buy a used model, get an idea of the real-world range and subtract 20-30% to estimate how the car would perform in harsh winter conditions.
  • Charging station implications. If there are no plugs on the route you plan to take to work or other daily activities, make sure the car has the technology to handle the cold. Newer Nissan Leafs have a reversible heat pump that helps range loss in the winter. Older models will not have this, so even if you see a low-mileage used Leaf it might not work for your needs.
  • The Chevrolet Bolt EV and any Tesla are great bets. While first-generation EVs maxed out at around 90 miles, there are now several models featuring over 200 miles of- driving range. Every Tesla – from the original base 60 kWh Model S through the 100 kWh S and X – offers better than 200 miles, while Chevy’s new Bolt EV got 238 miles for its EPA quote. These cars give you leeway.
  • Highway vs. city driving. If your daily routine takes you through city streets with frequent stops, you can get closer to range estimates in winter. Highway drivers will want to trim down their range estimate and then perform the subtraction accounting for the lowest temperatures.

 

Electric Cars’ Track Record in the Cold

Electric vehicles are already a fixture in places with very cold weather, including Norway, which has the highest adoption rate for EVs of any country on earth. Norway’s embrace of EVs came when the technology was at its earliest stages and cars like the first-gen Leaf were consumer’s best bet.

Moving forward, manufacturers will continue adapting plug-ins to accommodate different climates. With the first mass-market, long-range vehicles finally entering North America, it’s clear electric cars are having their moment. Don’t let the cold scare you off buying one for personal or company use.

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