Basics and latest technology of automotive lithium-ion secondary batteries: Post-LIB and all-solid-state batteries

Understanding Automotive Lithium-Ion Secondary Batteries

In recent years, the world has witnessed a significant shift towards sustainable energy solutions.
At the heart of this transformation is the development and use of lithium-ion secondary batteries, which have become an integral part of modern electric vehicles (EVs).
This article delves into the basics of these batteries, as well as the latest advancements, including post-lithium-ion batteries and all-solid-state batteries.

What Are Lithium-Ion Secondary Batteries?

Lithium-ion secondary batteries are rechargeable batteries that use lithium ions as the primary component of their electrochemistry.
They are designed to be reused hundreds or even thousands of times, making them ideal for repeated charging and discharging cycles, as required in automotive applications.
The term “secondary” indicates their reusable nature, distinguishing them from primary (non-rechargeable) batteries.

Basic Structure and Functionality

Lithium-ion batteries consist of four primary components: anode, cathode, electrolyte, and separator.
The anode, typically made of graphite, and the cathode, made of a lithium compound, are the positive and negative poles of the battery, respectively.
When the battery discharges, lithium ions move from the anode to the cathode through the electrolyte.
During charging, this process is reversed.
The separator prevents direct contact between the anode and the cathode, avoiding short circuits.

Advantages of Lithium-Ion Batteries in Automotive Use

Lithium-ion batteries offer several benefits for automotive applications.
Their high energy density allows for a greater amount of energy to be stored in a smaller space, essential for the high energy requirements of electric vehicles.
They also have a relatively low self-discharge rate, meaning they retain charge well when not in use.
Moreover, lithium-ion batteries are known for their long lifespan and efficiency, making them a cost-effective option over time.

Challenges in Current Lithium-Ion Technologies

Despite their numerous advantages, lithium-ion batteries also present some challenges.
One of the main challenges is the risk of thermal runaway, a phenomenon where the battery can overheat and potentially catch fire.
Additionally, the extraction and processing of lithium and other raw materials pose environmental and ethical concerns.
Recycling remains a challenge as well, as efficient processes for reclaiming materials from used batteries are still being developed.

Exploring Post-Lithium-Ion Batteries

To address both the performance limitations and resource concerns of current lithium-ion technology, researchers are exploring alternatives.
These alternatives are collectively known as post-lithium-ion batteries.

Sodium-Ion and Magnesium-Ion Batteries

Two promising post-lithium-ion technologies are sodium-ion and magnesium-ion batteries.
Sodium-ion batteries use sodium instead of lithium, making them a more abundant and potentially cheaper alternative.
While they have a lower energy density compared to lithium-ion batteries, recent advancements in materials and design are helping bridge this gap.

Magnesium-ion batteries, on the other hand, offer the potential for higher volumetric energy density and improved safety.
This is due to magnesium’s stable electrochemical behavior and the elimination of dendrite formation, which can cause short circuits in lithium-ion batteries.

Air-Breathing Batteries

Air-breathing batteries, such as lithium-air and zinc-air, are another area of interest.
These batteries use oxygen from the air as the cathode material, potentially delivering much higher energy densities.
However, challenges such as oxygen reactivity and the development of suitable electrolytes remain hurdles to their commercialization.

The Rise of All-Solid-State Batteries

One of the most promising advancements in battery technology is the development of all-solid-state batteries.
These batteries replace the liquid electrolyte found in traditional lithium-ion batteries with a solid electrolyte.

Benefits of All-Solid-State Batteries

All-solid-state batteries offer several benefits, including improved safety, as they eliminate the risk of leakage and flammability associated with liquid electrolytes.
They also promise higher energy densities and longer lifespans.
This makes them ideal candidates for automotive applications where efficient energy storage, safety, and longevity are critical.

Challenges and Developments

Despite their promise, all-solid-state batteries face significant development challenges.
Identifying and developing suitable solid electrolytes that provide both ionic conductivity and stability is a primary research focus.
Additionally, manufacturing processes need optimization to ensure scalability and cost-effectiveness.

Conclusion

The evolution of lithium-ion secondary batteries continues to reshape the automotive industry.
While current lithium-ion batteries power the majority of today’s electric vehicles, the development of post-lithium-ion and all-solid-state technologies holds great promise for the future.
These advancements aim to overcome existing challenges while enhancing battery performance, safety, and sustainability.
As the push for greener transportation grows, innovations in battery technology will play a crucial role in achieving a sustainable future for mobility.