There are many different materials used for the cathode, and you can change the separator or try another chemistry for the electrolyte. There are even options for the anode material, though one has dominated for a long time. Early attempts at lithium-ion batteries tried using solid lithium metal for the anode, but this produced serious stability problems. Problems that are still being worked on today. The breakthrough was the use of graphite for the anode.
Graphite consumes valuable space while not contributing additional energy capacity, but its sheet-like structure gives lithium ions safe housing while greatly improving cycle life and safety. This enabled the first Sony lithium-ion batteries in Even the first lithium-ion batteries had greater energy density than nickel-metal hydride batteries, holding more charge in less space while weighing less. They also operate with a higher cell voltage, which can be useful. Lithium-ion batteries are more expensive, and the organic solvent used for the electrolyte is flammable, creating a fire risk that must be carefully managed.
But the lithium-ion battery dominates where space and weight is at a premium, in places like a laptop or electric vehicle. Batteries have more than one or two important characteristics, and so they are often represented by a spider chart like the one below. Below, you can see how different cathode materials change the way battery types perform on six measures.
Power is the rate at which energy can be released. A battery strong enough to launch and keep aloft a commercial jet for 1, km requires a lot of energy to be released in very little time, especially during takeoff.
Tackling the power challenge requires us to look inside the black box of commercial batteries. The most cutting-edge battery chemistry we currently have is lithium-ion. Most experts agree that no other chemistry is going disrupt lithium-ion for at least another decade or more. A lithium-ion battery has two electrodes cathode and anode with a separator a material that conducts ions but not electrons, designed to prevent shorting in the middle and an electrolyte usually liquid to enable the flow of lithium ions back and forth between the electrodes.
When a battery is charging, the ions travel from the cathode to the anode; when the battery is powering something, the ions move in the opposite direction. Imagine two loaves of sliced bread. Each loaf is an electrode: the left one is the cathode and the right is one the anode. In the discharged state—i. When the battery is charging, each lithium ion is extracted from between the slices and forced to travel through the liquid electrolyte.
The separator acts as a checkpoint ensuring only lithium ions pass through to the graphite loaf. Drawing lithium-ions out of the cathode loaf too quickly can cause the slices to develop flaws and eventually break down. Every charge and discharge causes the loaf to weaken that little bit. Various companies are working on solutions to the problem. One idea is to replace layered electrodes with something structurally stronger. These structures are better at handling the flow of lithium ions in and out of the material.
These batteries sit at the charging station slowly drawing small amounts of power over a long period from the grid until they are fully charged.
When the car leaves, the station battery starts recharging again. Still, nobody has yet built a battery powerful enough to rapidly deliver the energy needed for a commercial plane to defeat gravity.
Startups are looking to build smaller planes seating up to 12 people , which could fly on relatively lower power-dense batteries, or electric hybrid planes , where jet fuel does the hard lifting and batteries do the coasting.
Currently, a solid-state cell costs about eight times more to make than a liquid li-ion battery, experts say. Japan's Toyota Motor Corp T is one of the front runners to mass produce solid-state batteries. It has said it is struggling with their short service life but still intends to start making them by mid s. In addition to Toyota's in-house research, it has teamed up with Japan's Panasonic Corp DE has invested in Bill Gates-backed U.
N , which aims to introduce its battery in for VW's EVs and eventually for other carmakers. Solid electrolytes are more energy dense, allowing for faster charging, greater range, and longer shelf-life. Longer-lasting batteries reduce the need for expensive storage systems and energy costs for consumers. They handle heat better, but also operate at extremely cold temperatures. Unsurprisingly, EV manufacturers are eager for a breakthrough. Right now, Tesla has a thermal management and electronic control technology which gives it an advantage over its competitors.
By removing temperature as a vulnerability, solid-state technology could allow others to cut costs and compete. Toyota has made battery technology a priority, regarding solid-state as a solution to the limited range and long charge time hindering widespread proliferation of EVs. They hope to sell the first solid-state battery-equipped EV this decade.
Transportation is not the only industry that stands to benefit. Improved batteries in smartphones will potentially allow up to three days of continued usage without changes to design or weight. Other devices from laptops to utility storage units will similarly gain in charge duration.
0コメント