The first fuel-powered automobile was invented in 1885

燃料で動く車が発明されたのは1885年

by Karl Benz of Mercedes-Benz,

カール･ベンツの発明品 原動機付き三輪車で

who applied for a patent for his three wheeled,

翌年 彼は特許を申請した

gasoline-powered Motorwagen the following year.

ただし その前から車はあった

But there were cars even before that,

1830年代に発明された電気自動車

like this electric car that was invented in the 1830s,

蒸気で動いた三輪車は 1769年からフランスで乗り回されていた

and this steam-powered tricycle

ところが驚くことに 世界初のソーラーカーが生まれたのは1955年

which had been rolling around France way back in 1769.

それでも 全長は38センチ 人が乗るには小さすぎた

Incredibly, it wasn't until 1955

しかし1962年には 運転可能なソーラーカーが誕生

that the world's first solar-powered vehicle was demonstrated.

[番組ホスト　マレン･ハンスバーガー]

Even then, at a mere 38cm long,

太陽光を動力とする車の発明は―

it was too tiny for a human to drive.

蒸気を使う車の発明より難しかった

But then, in 1962,

それに化石燃料を使う車よりもね

a drivable solar-powered car was finally unveiled.

一般人が買えるほど メジャーな存在ではないものの

Turns out, building a vehicle that's powered by the sun

ソーラーカーは現実のものとなった

is actually a lot more challenging

これらのソーラーカーは 予想より速く 遠くまで走行可能

than using steam or electricity.

現代技術を応用し よりクリーンで 環境に優しい未来へ向かっている

Or really old carbon, also known as fossil fuel.

今回は世界最速のソーラーカーをご紹介

But while commercially available solar cars

ソーラーカーが動く仕組みを説明するわ

haven't yet made it onto our roadways,

ソーラーカーはSFに出てくる乗り物？

what seems like an impossible piece of technology

あまりにも未来的で複雑な技術であり 現実には存在しないと？

is actually very much a reality.

1955年にウィリアム･コブが発明したモデルカー

And these solar cars are capable of going faster

サンモービルを見る限り ソーラーカーはシンプルだった

and further than you might think.

これは今のソーラーカー

What's more, the technology in today's solar vehicles

モデルカーだけど機能はフル装備

could drive us all toward a cleaner, greener future.

全長は８センチでサンモービルより小型だけど

So in this episode, we take a look under the hood

構成要素はそろってる

of one of the world's fastest solar cars

光子を電気に変換するソーラーパネル

to better understand,

太陽光を電気に変換する過程は第３章を見てね

how does a solar car actually work?

電気はここを通って小さな直流モーターへ到達

Like me, you've probably thought of solar cars

モーターが電気をエネルギーに変換し―

as something out of science fiction.

車を動かす様子を見て

Like, a technology so futuristic and complex

[デレク･ミューラー]

that it feels like it can't actually exist in the real world.

太陽電池が日光を浴びていれば―

But going back to William Cobb's

車輪を回し 車を動かす動力は得られる

38-centimeter model car from 1955,

でも日光が遮られると...

the Sunmobile,

車は ただの置物に

it seems like solar cars of the past

これは とても基本的なデモ走行で

were pretty simple machines.

過去のソーラーカーの動作が分かる

This is today's solar car.

日光があれば動くし なければ動かなかった

Okay, it's a model solar car,

ソーラーカーは使えないとされた理由が分かる

but it is fully functional.

今は もう少し洗練されてる

It's about 8cm long, just over three inches,

[2019 ワールドソーラーチャレンジ]

so it's even smaller than that Sunmobile.

いえ すごく洗練されてる

But it's got all the same major components.

ワールドソーラーチャレンジに出る車は―

Here's the solar panel

最新の太陽光発電技術以外の面でも革新的

that converts those photons into electricity.

デザインやエンジニアリング バッテリーね

We actually covered that whole process in detail

レースカーの内部を探るため―

in a previous chapter, so check that out.

スタンフォード大学のチームメンバーに連絡した

That electricity then travels here

コーリ･ブレンデル スタンフォードのチームリーダーです

to this small direct current motor,

キャメロン･ヘインズワース　３年生だ

and that motor then converts electricity

ジュリア･ゴードン　空気力学チームよ

into mechanical energy, which propels the car.

レースの準備期間中―

Check it out.

何でも屋として働いてるわ

Now, as long as the car's solar cells are exposed to sunlight,

ジュリアはドライバーだったけど―

there's enough power to keep the wheels turning

2019年のレースで好成績を収められなかった

and the car moving.

街なかを抜けたところで 煙の匂いがしたのを覚えてるわ

But if that sunlight is cut off...

何だかヤバそうな匂いがする

then the car becomes a paperweight.

パネルを引き剥がしたら 車から炎が噴き出したの

Now, this basic demonstration,

2019年は残念な結果に終わったけど

and yes, it is a very basic demonstration,

チームは この体験をポジティブに捉えた

it shows how solar cars of the past worked.

常に勝ちたいと願ってる

If there were sunlight, they could go.

うちのチームが原則としてるのは―

No sunlight, no go.

工学的な面でも技術的な面でも とにかく限界に挑むこと

So you can see why solar cars of the past

さまざまな分野の専門家と ゴールを目指すのは最高の体験だ

have not been considered a viable option.

斬新なエンジニアリングの概念を 数多く学べるからね

Luckily, today's solar cars are a bit more sophisticated.

革新性を目指すチームは レースカーのデザインも大胆に変更

Okay, a lot more sophisticated.

30年間の歴史で14台目の車よ

The solar racers competing in the world Solar Challenge, for example,

今まではマルチフェアリング型

don't just use the latest in photovoltaic technology,

２隻の小舟を並べたカタマラン船風だった

they've also adopted innovations

“ブラックマンバ”は新型だ

in design, engineering and battery technology.

ブレットカー風で １つの覆いに全車輪が収まる

To get a closer look under the hood

空気力学的に覆いは１つのほうがいい

of one of these solar racers,

余分なエッジを取り除けるわ

I got to connect with a few members

車輪をまとめたことで 車を傾けやすくなった

of the racing team from Stanford University.

残る問題はアレイの大きさ

My name is Cori Brendel. I was the team lead

車を小型にするため 効率性の高いガリウムヒ素太陽電池を採用

for the 2019 Stanford Solar Car Project cycle.

ドライバーを右に置き 非対称にすれば―

My name is Cameron Haynesworth.

空気力学的に有利で 太陽を遮ることもない

I'm a junior at Stanford University.

パネルが日陰にならないんだ

Hi, I'm Julia Gordon.

ソーラーチャレンジ初の非対称な車だよ

I started out on the aerodynamics team,

他は皆 ドライバーを真ん中に置いてた

and throughout the race preparation time,

より野心的に駆動力を高めるための大胆な変更で

I ended up in a kind of jack-of-all-trades role.

ブラックマンバの可能性が広がった

Julia was actually behind the wheel for the 2019 race,

もう１つのアップグレードが ガリウムヒ素のソーラーパネル

which, unfortunately, didn't go so well for the Stanford team.

シリコン製から ガリウムヒ素のものに変更し―

I think, like, right as we got outside the city,

ソーラーパネルの効率性を高めた

I remember I started smelling smoke.

ガリウムヒ素の技術について 第３章で話したので―

I smell a not good smell.

今回は おさらいを

I remember watching as they pulled the panel off,

ガリウムヒ素のアレイは3.56平方メートル

just flames come out of the car.

これにかかる費用は約10万ドル

MAREN: Although the Stanford team

ソーラーチャレンジではガリウムヒ素の アレイの大きさを制限してる

had a disappointing performance in 2019,

だから資金力のないチームも この技術を使って公平に戦える

the team felt that it was overall

ガリウムヒ素のアレイは 電流も電圧も全く異なる新技術で

an overwhelmingly positive experience.

電流が異なるなら他も変えるべきよ

So we always go in with wanting to win.

バッテリーを車に適合させ―

But I think one of the big principles underlying the team

ドライバーとバランスが取れるよう 対面に配置した

is just pushing the envelope

全く新しい要素なの

for what we can do with engineering and technology.

バッテリーは主要なアップグレード点

So being able to work on a team

これまではパネルで作った電気を 直接 モーターへ送っていた

that has so many different expertises

ブラックマンバのような近代型は―

working toward one common goal is great,

リチウムイオン電池を充電し 動力を与えてる

because you just get exposed to so many really new

基本的に必要なのは ソーラーアレイ バッテリー モーター

and kind of novel engineering concepts.

それらが車の内部回路に接続される

This drive to innovate pushed the Stanford team

アレイで作られた電気がバッテリーを充電し

to make a pivotal change in their race car's design.

モーターへとつながる

The project has been around for 30 years now.

日光が直接当たらなくても走れるの

This was our 14th vehicle that we've built.

電気の供給が需要を超える場合もあるから

We've always done like a multi-fairing car.

電力を蓄える機能も必要になる

Usually that's a catamaran,

すべてのアップグレードを施し デザインも一新して―

which is your traditional two-fairing vehicle.

重量を180キロに絞ったブラックマンバが 2019年に登場

CAMERON: Yeah, Black Mamba was definitely a new car.

フェアリングは単体で形は非対称

We went to Black Mamba, which is a bullet car design,

3.56平方メートルのシングル･ジャンクションに

which means all of the wheels are in one fairing.

ガリウムヒ素の薄いソーラーアレイ

Um, I'm not an aerodynamics expert,

そしてリチウムイオン電池が―

but single fairing is better for aero

最大時速110キロでマンバを走行させる

because you are eliminating extra edges on your car.

高速に乗れるわ

CAMERON: The trade-off to that is,

ただ レースでは最高速度が出せなかった

as you move your wheels closer together,

2019年の事故でスタンフォードチームは―

it's a lot easier to tip your car.

バッテリーとモーターの 良好な接続が不可欠と学んだ

And the other problem is with the array size.

車が炎に包まれる前に バッテリーは取り出せたわ

CORI: To get a really small car,

リチウムイオン電池は引火しやすい

we went with gallium-arsenide cells

とても危険な技術よ

'cause when you use more efficient cells,

ショートを起こせば即座に バッテリーに引火する

you can reduce the size of your car.

このことについては次の２章で話す予定よ

CAMERON: We put the driver on the right side of the car,

バッテリーについて詳しく説明する

so it was asymmetric, which had some advantages with the aerodynamics

まずリチウムイオン電池の話からよ

as well as the shading of the sun on our solar panels,

この続きも ぜひお見逃しなく

so that the driver didn't shade the solar panels.

And it was also the first asymmetrical bullet car in WSC.

All the other bullet cars in WSC were center driver.

JULIA: It felt like this one radical change

just kind of spurred off more ambition and more drive

to see how far we can really push Black Mamba.

Another major upgrade to the Stanford solar racer...

gallium-arsenide solar panels.

CAMERON: In the past we had done a silicon array.

Gallium-arsenide is a new development in solar panel technology

that allows for higher efficiencies in solar panels.

We talked about gallium-arsenide technology

in our previous chapter on solar panels.

So, go learn all about that here.

CORI: The size of the gallium-arsenide array

was 3.56 square meters.

And to cover that size array, you need about 100 grand.

Now, to keep things competitive, the World Solar Challenge

did limit the size of gallium-arsenide arrays for each team,

so that teams without the resources,

meaning money, to access this technology,

could still compete in the race fairly.

So then, gallium-arsenide was a whole new technology

with different current and voltage specifications,

so then that changes the entire electrical system,

because when you're operating with different current,

you have to change things down there, too.

On the battery side,

it's a whole new form-factor that you have to fit in the car.

For balance reasons, you'd want the battery across from your driver,

so that your driver and battery can balance each other out,

so battery had a whole new form factor.

MAREN: The battery is one of the key upgrades

to today's solar cars.

Whereas solar cars of the past

sent electricity generated by their solar panels

directly to the motor,

modern solar cars, like Stanford's Black Mamba,

use photovoltaic technology

to charge the lithium-ion batteries

that then power the vehicle.

So the basic gist is that

you've got your solar array, battery and motors.

Then those are all connected

by the internal circuitry of the car.

So as the solar array generates power,

that goes into a battery pack, which starts recharging,

and the solar ray also connects out to the motors.

MAREN: This allows these solar cars to run

even when there's no direct sunlight available.

CORI: There's times when you have more supply

than you have demand, or vice versa.

So really, what you need is you need to have some kind of storage device

so you can store all that power.

MAREN: Now, after all of these upgrades

and really a total reimagining of their solar racer,

the Stanford team's Black Mamba

came into the 2019 World Solar Challenge

at a sleek 180 kilograms.

Its single fairing asymmetric bullet design

with a 3.56 square meter single junction

thin film gallium-arsenide solar array

and 45 amp lithium-ion battery

pushed Mamba to a top speed

of around 110 kilometers per hour.

That is highway speed.

Unfortunately, Black Mamba didn't hit top speed in Australia,

because as the Stanford team learned the hard way in 2019,

having a good battery to motor connection

is absolutely critical.

JULIA: We managed to get the battery out of the car

before anything else really caught on fire.

CAMERON: When lithium-ion batteries go,

they go pretty violently.

CORI: Lithium-ion technology

is definitely a dangerous technology.

If you do have a short, you can get a battery fire

because things will just propagate really, really quickly.

Which brings us to the next two chapters

of our Light Speed Learning Playlist,

where we're gonna take a deep dive

into the wonderful world of batteries.

First up. How do lithium-ion batteries work?

Click the link to find out, or just let this playlist play.