in almost every portable electronic device.

幾乎在每一個便攜式電子設備中。

They're in smartphones, laptops, and even in our cars.

它們存在於智能手機、筆記本電腦中，甚至我們的汽車中。

In fact, batteries are one of the keys to realizing

事實上，電池是實現的關鍵之一。

a 100% renewable energy future.

100%可再生能源的未來。

In 2018, there were over five million electric cars on the road,

2018年，有超過500萬輛電動汽車在路上行駛。

which includes both hybrid vehicles

其中包括混合動力車

and fully battery powered electric cars.

和全電池供電的電動汽車。

And their popularity only continues to grow.

而且他們的知名度只會不斷提高。

Since batteries are powering more and more of our lives,

由於電池為我們的生活提供了越來越多的動力。

why don't we explore how exactly batteries work,

我們為什麼不探討一下電池的工作原理呢？

and what makes lithium-ion batteries so special?

又是什麼讓鋰離子電池如此特別？

Now, there are a bunch of batteries out there,

現在，有一堆電池在那裡。

made of different materials, in different shapes,

由不同的材料製成，形狀各異。

and with different charge capabilities.

並具有不同的充電能力。

But on the most basic level,

但在最基本的層面上。

batteries are composed of electrochemical cells.

電池由電化學電池組成。

And the materials that make up an electrochemical cell

組成電化學電池的材料是

can create the positive and negative sides

可以製造正反兩方面

you see on the either end of that battery.

你看在那電池的兩端。

Inside a single electrochemical cell,

在單個電化學電池內。

there are a few main parts

有幾個主要部分

that help the cell create electricity.

幫助細胞產生電能的。

Two electrodes, which are the materials

兩個電極，是材料

that make the battery ends positive or negative.

使電池端正或負極。

The negative side is called the anode,

負的一面稱為陽極。

and the positive side is called the cathode.

而正極稱為陰極。

The next part is called the electrolyte,

接下來的部分叫做電解質。

which sits between the anode and the cathode.

它位於陽極和陰極之間。

And this is important, because it's what enables

這一點很重要，因為它能使

charged ions to flow between the two electrodes.

帶電離子在兩個電極之間流動。

The electrolyte can be liquid or solid,

電解液可以是液體或固體。

or any material that helps the chemical reaction flow smoothly.

或任何有助於化學反應順利進行的材料。

And finally, there's a semipermeable layer

最後，還有一個半透膜層。

that keeps everything separate

涇渭分明

so that we can control the reaction.

這樣我們就可以控制反應。

Now, if we wanted to power, say, a flashlight,

現在，如果我們想給手電筒供電，比如說，一個手電筒。

you would add an external circuit

你會添加一個外部電路

that connects the anode to the light bulb

陽極和燈泡的連接處

and the flashlight to the cathode.

並將手電筒對準陰極。

When we add a charge to this circuit,

當我們在這個電路上加一個電荷。

we initiate a chemical reaction

我們發起化學反應

between the anode and the electrolyte.

陽極和電解質之間。

This releases electrons

這將釋放電子

and leaves leftover ions at the anode.

並在陽極留下剩餘離子。

These released electrons

這些釋放的電子

will travel through our circuit as electricity,

會以電的形式通過我們的電路。

ending up in the cathode.

最終在陰極結束。

At the same time, the electrolyte

同時，電解質

will help the ions they left behind at the anode

將有助於它們在陽極留下的離子。

flow through the semipermeable barrier

流過半透壁

and meet the electrons at the cathode.

並在陰極與電子相遇。

This whole process is called

這整個過程叫做

a reduction-oxidation reaction,

還原-氧化反應；

also commonly referred to as a redox reaction.

也就是通常所說的氧化還原反應。

Oxidation is where a material loses electrons,

氧化作用是指材料失去電子。

and reduction is when it accept electrons.

而還原是指它接受電子時。

Now, when we talk about battery performance,

現在，當我們談論電池性能時。

we have to consider both energy and power density.

我們必須同時考慮能量和功率密度。

And a good example to highlight the difference

並舉出一個很好的例子來強調兩者的區別

between energy and power density,

能量和功率密度之間。

is comparing a mug to a large jug

濫竽充數

with one of those narrow bottlenecks.

與那些狹窄的瓶頸之一。

If your water represents energy,

如果你的水代表能量。

and you fill both vessels with water,

你把兩個容器都裝滿水。

you see that the jug has a greater overall energy storage.

你看這把壺的整體儲能更大。

It can simply hold more water or energy.

它可以簡單地容納更多的水或能量。

But if we were to pour that water out,

但如果我們要把這些水倒出來。

well, then it's clear that the water or that stored energy

那麼，很顯然，水或儲存的能量。

comes out of the mug at a much faster rate,

以更快的速度從杯子裡出來。

demonstrating that the mug has a higher power output.

證明該杯子具有較高的功率輸出。

Energy density is defined

能量密度定義為

as how much energy is within a given mass.

作為給定品質內有多少能量。

So if something has a high energy density,

所以，如果某個東西的能量密度很高。

it means it can store a lot of energy

意味著它可以儲存大量的能量

in a small amount of mass.

在少量的品質。

Power density, on the other hand, is defined as,

而功率密度則定義為：

you guessed it, how much power is within a given mass.

你猜對了，在一個給定的品質內有多少力量。

So when something has a high power density,

所以，當東西的功率密度很高時。

it can output large amounts of energy

它可以輸出大量的能量

in a short amount of time.

在短時間內。

So if you have a device with high energy density

所以，如果你有一個高能量密度的設備。

and low power density,

和低功率密度。

it means that the device can store a lot of energy

這意味著該設備可以存儲大量的能量。

and doesn't use it up quickly.

並不會很快用完。

A good example of this is your very own phone.

一個很好的例子就是你自己的手機。

It actually has a small battery,

其實它有一個小電池。

but can run for a long time.

但可以運行很長時間。

Now, you may notice your phone doesn't really generate that much power.

現在，你可能會注意到你的手機並沒有真正產生那麼多的電力。

I mean, it probably has enough power

我的意思是，它可能有足夠的權力

to have all of your apps open while streaming

在串流時打開所有的應用程序

cool science videos like this one,

像這樣酷炫的科學視頻。

but then you'd probably have to recharge it pretty soon afterwards.

但之後你可能很快就要充電了。

You'll find that most phones today

你會發現，如今大多數手機

use lithium-ion batteries,

使用鋰離子電池。

and materials are important

和材料的重要性

for chemical reactions in battery cells.

用於電池單元的化學反應。

So, in the case of lithium-ion cells,

所以，在鋰離子電池的情況下。

both the anode and the cathode are made of materials

陽極和陰極都是由材料製成。

that can enhance their ability to absorb lithium ions.

可以增強其吸收鋰離子的能力。

This means the ions are held

這意味著，離子的持有量是

inside the structure of the material,

在材料的結構裡面。

and they can't get loose.

而他們卻無法脫身。

In most cases, the anode is made of graphite,

在大多數情況下，陽極是由石墨製成的。

which has this structure of carbon atoms.

其中具有這種結構的碳原子。

This structure allows the graphite anode

這種結構使得石墨陽極

to store positive lithium ions,

以儲存正鋰離子。

while the cathode, typically made of lithium cobalt oxide,

而陰極，一般由氧化鈷鋰製成。

has a structure that also is conducive

有一個結構，也有利於

to storing lithium ions.

以儲存鋰離子。

These enhanced materials are key

這些強化材料是關鍵

for a couple of different reasons.

有幾個不同的原因。

It means that the cell can store more energy

這意味著細胞可以儲存更多的能量

while remaining small, and that's energy density.

而保持小，這就是能量密度。

And this also means the battery is rechargeable.

而這也意味著電池是可以充電的。

When we want to use a lithium-ion battery,

當我們要使用鋰離子電池時。

it works similarly to our other batteries.

它的工作原理與我們的其他電池類似。

As the cell gets used,

隨著小區的使用。

those electrons are freed from the anode,

這些電子從陽極釋放出來。

and they shuffle through an external circuit to the cathode.

並通過外部電路將它們洗牌到陰極。

While the electrons move through the circuit as electricity,

當電子以電的形式在電路中運動時。

the lithium ions left behind

殘餘的鋰離子

travel through the electrolyte to the cathode.

通過電解質傳到陰極。

And there, they get absorbed and stay put

在那裡，它們會被吸收，並保持原樣

until the device that uses the battery

直到使用電池的設備

is plugged in and begins the charging cycle.

插上電源並開始充電循環。

Then they all do the whole process again, but backward.

然後他們都再做一次整個過程，但要倒退。

Also, depending on how much energy density you need,

另外，根據你需要多少能量密度。

the cathode can be created with different metal oxides

陰極可以用不同的金屬氧化物來製造。

for different applications.

針對不同的應用。

For example, lithium cobalt oxide is what's used in our phones,

比如，我們手機裡用的就是氧化鈷鋰。

while something like a Tesla vehicle

而像特斯拉汽車

uses lithium nickel cobalt aluminum oxide.

採用鎳鈷鋁氧化鋰。

So you were probably aware

所以你可能知道

that electric cars use lithium-ion batteries,

即電動汽車使用鋰離子電池。

but maybe you didn't know that Tesla cars used

但也許你不知道，特斯拉汽車使用的是。

such a different kind of lithium-ion battery.

這樣一種不同的鋰離子電池。

DEREK: Electric vehicles have been developing for decades now,

DEREK：電動汽車已經發展了幾十年了。

but they only sort of hit a tipping point recently.

但他們最近才算是達到了一個臨界點。

I've been driving one for a couple of years,

我開了好幾年的車了。

and I just wouldn't go back.

我只是不會回去。

And part of that is due to their

而部分原因是由於他們的

very innovative battery technology.

非常創新的電池技術。

Electric vehicles look pretty different under the hood

電動汽車的引擎蓋下看起來很不一樣

from internal combustion engine cars.

從內燃機汽車。

I mean, there's not much to see here,

我是說，這裡沒什麼好看的。

it's just a storage space.

它只是一個存儲空間。

The batteries that this car uses are individual cells,

這輛車使用的電池是獨立電池。

which are packaged together into modules,

它們被打包成模塊。

and modules joined together to form the battery pack,

和模塊連接在一起，形成電池組。

which actually sits down here

竟然坐在這裡

along the bottom of the vehicle.

沿著車輛的底部。

And it's really heavy, so it gives the car

而且它真的很重，所以它給了汽車。

a low center of gravity.

低重心。

Now, those batteries are pretty impressive.

現在，這些電池是相當令人印象深刻。

Lithium-ion.

鋰離子。

In the Model S version of this car,

在這款車的S型版本中。

there are 7,000 of them stuck together,

有七千人粘在一起。

and that can give these cars a range

而這可以給這些車一個範圍

over 595 kilometers.

超過595公里。

The next most efficient electric cars on the market

市場上下一個最高效的電動汽車

only have a range of about 415 kilometers.

只有415公里左右的射程。

And this huge gap demonstrates that Tesla

而這種巨大的差距表明，特斯拉

is leading the charge, at least for now,

是上司的，至少目前是這樣。

in terms of energy density and even power density,

在能量密度乃至功率密度方面。

in a way that makes those electric cars

的方式，使這些電動汽車

relatively affordable for a mass market.

對於大眾市場來說，相對實惠。

But lithium-ion batteries do have their downsides.

但鋰離子電池也有其缺點。

They're not super powerful, they're expensive,

它們不是超級強大，而是昂貴。

the materials they're made from are unsustainable,

他們的材料是不可持續的。

and their electrolyte can be flammable,

而其電解質可能是易燃的。

making the product potentially hazardous.

使該產品具有潛在的危險性。

So clearly there are improvements to be made.

所以，很明顯是要改進的。

But what's it gonna take to make an even better battery?

但要怎樣才能做出更好的電池呢？

Check out our next episode

請看我們的下一集

to learn what scientists are working on today.

以瞭解科學家們今天正在進行的工作。