エネルギー

EVのバッテリー容量が減少しましたか？水素のせい

公開日 2024年9月18日

更新日 2026年5月31日

著者

Jonathan Schramm

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バッテリーのエネルギー損失

Even after decades of utilizing them in electronics—and now EVs—we still do not fully understand lithium-ion batteries. For example, one such issue is the tendency of batteries to self-discharge over time. This is an issue that tends to become larger over time, and a major reason why batteries reach the end of their useful life after 7-10 years in most cases.

自己放電は、コバルトを使用しないバッテリー化学系でも問題となり、コバルトが高価で人権侵害の疑いがある条件で生産されている場合でも採用が制限されます。

最近まで、科学者たちは自己放電がリチウムイオンに関連していると考えていました（詳細は下記参照）。しかし、これは事実ではないようです。

研究者らは最近、実際に自己放電の原因はプロトン（水素原子核）であることを発表しました。この発見は新しい設計や問題緩和の方法への道を開き、将来のバッテリーを大幅に改善する可能性があります。

彼らはこの成果を、Scienceという権威ある誌に「層状正極における溶媒媒介酸化物水素化」というタイトルで掲載しました。

This was achieved with a massive collaborative effort bringing together researchers from the University of Colorado, DEVCOM Army Research Laboratory, SLAC National Accelerator Laboratory, Argonne National Laboratory, Pacific Northwest National Laboratory, University of Houston, National Renewable Energy Laboratory, Oregon State University, Stanford University, Lawrence Berkeley National Laboratory, National Taiwan University.

従来のパラダイム

Lithium batteries work by moving lithium ions from the anode side to the cathode side through an electrolyte. This flow creates an electric current. The process is reversed when charging the battery.

出典: ResearchGate

これまでの前提は、自己放電がリチウムイオンが正極に捕捉されてしまい、充電時にアノードへ戻らず、利用可能なイオンが減少して電力が生成できなくなることに起因すると考えられていました。

This has been central to improving lithium-ion designs, with many attempts to optimize the flow of lithium-ion and make their returns to the anode as perfect as possible. It appears, however, that this is not the actual issue.

水素がリチウムの位置を奪う

The researchers were able to analyze in-depth battery material using a powerful X-ray machine at the U.S. Department of Energy’s Argonne National Laboratory in Illinois.

その結果、バッテリー電解質中の水素分子が正極材料に侵入し、リチウムイオンの位置を奪うことが判明しました。これによりリチウムイオンが占有できる空間が減少し、バッテリー容量が低下します。

この現象は主に正極の層状遷移金属酸化物で起こります。

さらに、このプロセスは正極自体を物理的に損傷させ、ひび割れを引き起こし、バッテリーの劣化を加速させます。

So not only do the hydrogen protons reduce the battery life by reducing the capacity, but also by causing direct damages that were until now assumed to be caused by lithium-ions.

直接的な可能性

EVの制限を解決する

A key limitation in EV adoption & switching to cobalt-free batteries is that alternative chemistries display a relatively lower range. For some drivers, this is an unacceptable limitation compared to fuel cars.

バッテリーパックの寿命が車体全体より短くなる懸念や、予測できない追加費用が発生することは、EVへの乗り換えを阻む大きな要因です。特に多くのEVモデルは依然として購入価格が高めです。

This short lifespan is also an ecological concern, as it means more material needs to be mined, more energy is consumed to produce the batteries, and more efforts need to be put into recycling.

正極の寿命改善

Now that we know hydrogen, not lithium, is to blame for cathode degradation, we are more likely to find effective solutions. The researchers for example discuss the use of a special coating on the cathode that could block the hydrogen molecules.

Another option would be to use different electrolytes that do not generate hydrogen in the first place.

固体電池

This is also an encouraging discovery for solid-state batteries. As these designs do not use an electrolyte at all, they might be entirely immune from the problems caused by hydrogen created from the electrolyte.

In itself, this could explain some of the remarkable performance of solid-state batteries.

先進バッテリー技術への投資

Batteries are at the center of the trend of electrification, itself a major multi-trillion-dollar endeavor looking to remove fossil fuels from our power sources. And more reliable, cheaper, or more durable batteries will be at the center of the effort of “greening” our energy system.

You can invest in battery-related companies through many brokers, and you can find here, on securities.io, our recommendations for the best brokers in the USA, Canada, Australia, the UK, as well as many other countries.

If you are not interested in picking specific battery companies, you can also look into battery ETFs like Amplify Lithium & Battery Technology ETF (BATT), Global X’s Lithium & Battery Tech ETF (LIT), or the WisdomTree Battery Solutions UCITS ETF (WT ), which will provide a more diversified exposure to capitalize on the growing battery industry.

Or you can look at our article on the “投資すべきトップ10バッテリーストック” and “トップ10バッテリーメタル＆再生可能エネルギー鉱業株“.

先進バッテリー企業

1. CATL (300750.SZ)

We talked already of CATL technological lead. The company is the global leader in battery manufacturing, producing more than half of the global battery volume. It is present at every step of the battery manufacturing supply chain and is a leader in battery technology.

This is true for lithium-ion batteries, where the company has been a long-established leader for a long time. Now it looks small in comparison to the latest announcement.

CATL has also announced in the past impressive progress on multiple other battery types :

出典: CATL

CATLは中国でバッテリーリサイクル施設に3.25億ドルを投資. CATLは特にニッケル、コバルト、マンガンで99.6%、リチウムで91%の回収率という顕著な回収率を達成しています。

Thanks to its scale, focus, and R&D achievements, CATL is likely to be at the forefront of battery innovation, manufacturing, and recycling.

This makes it a key partner for EV manufacturers, including Tesla (TSLA ), NIO, Ford, Stellantis, etc, with Hyundai recently added to CATL growing rooster of strategic alliances.

In addition, the lessons learned in one chemistry can be applicable in another, so we might see soon honeycomb or condensed-state sodium-ion batteries for example. The economies of scale in producing half of the world’s batteries are also likely applicable to the whole company, regardless of the specific technology used in an individual product.

2. BYD (BYDDY)

A long-time challenger of Tesla in the EV market, BYD has become a serious competitor not only for Tesla but for virtually all automakers.

The company evolved from its origin as a supplier of lithium-ion phone batteries to selling almost as many EVs as Tesla in China (the world’s largest EV market) and being the best-selling EV in Thailand, Sweden, Australia, New Zealand, Singapore, Israel, and Brazil.

BYD is a large part of why China suddenly became the world’s largest car exporter in 2023, surpassing Japan. The company’s aggressive overseas expansion is also carried by new factories, like in Hungary.

And with the release of $10,000-$12,000 cars like the Seagul, using sodium batteries, a whole new market might open for BYD EVs.

出典: By User3204 – Own work, CC BY-SA 4.0

Still a battery manufacturer at its core, BYD is a serious challenger to CATL in the LFP (lithium iron phosphate) battery market, with a 41.1% market share in China (compared to CATL’s 33.9%).

The “flood” of cheap EVs produced by BYD into the European and American markets is likely to be met with some level of protectionism (even above the recently imposed tariffs), which could hinder BYD’s growth.

But at the same time, cheap Chinese EVs are already a great success in the rest of the world, which does not have incumbents much in the way of domestic automakers to protect, including the entirety of South America, Russia, Africa, the Middle East, and Southeast Asia.

This represents several billion potential customers for BYD, living in countries eager to strike a geopolitical balance and stay on good terms with both the West and China, so it is unlikely to create too strong protectionist barriers.

And even in the EU or the USA, BYD might stay competitive, thanks to the much higher prices of local EV manufacturers compared to prices in China, as well as localization of the production out of China for these markets, like, for example, in Eastern Europe, Mexico, or Turkey.