[Infinite Power] Battery Revolution, All-Solid-State Battery

Hyundai Motor EV Concept Car

[Asia Economy Reporter Park Soyeon] The four main components of a lithium-ion battery are the cathode, anode, separator, and electrolyte. Electricity is generated as lithium ions move between the cathode and anode.

Currently, the lithium-ion batteries used in applications such as smartphones, power tools, electric bicycles, and electric vehicles employ liquid electrolytes.

In contrast, all-solid-state batteries are batteries in which the electrolyte component among the four main materials has changed from liquid to solid.

Structurally, lithium-ion batteries have a separator that prevents contact between the cathode and anode, with liquid electrolyte present alongside the cathode, anode, and separator. However, in all-solid-state batteries, the solid electrolyte replaces the separator and also performs its function.

The biggest concern for users of lithium-ion batteries is safety. Because liquid electrolytes are used, there is a risk of battery swelling due to temperature changes or leakage caused by external shocks, which can lead to fire or explosion in case of battery damage.

On the other hand, all-solid-state batteries with solid electrolytes are structurally rigid and stable, and even if the electrolyte is damaged, the battery can maintain its shape, thereby enhancing safety.

◇Reasons for Developing All-Solid-State Batteries

So why are many battery companies focusing their efforts on developing all-solid-state batteries, the next-generation battery? It is because the capacity of batteries for electric vehicles needs to be increased.

Many market research organizations predict that electric vehicles will replace internal combustion engine vehicles and become the mainstream in the automotive industry. To make electric vehicles a definite trend, increasing the capacity of the core component?the battery for electric vehicles?is paramount.

The first reason for increasing electric vehicle battery capacity is driving range. Currently, the driving range of electric vehicles in operation does not match the 600?700 km range of internal combustion engine vehicles.

There are two ways to increase battery capacity: the first is to increase the number of batteries. However, this approach is difficult to realize because it raises battery costs and reduces space efficiency.

Therefore, research and development should focus on increasing energy density, as batteries have evolved so far. The continuous increase in electric vehicle driving range while maintaining price has been possible because the energy density of electric vehicle batteries has been steadily improved.

This aligns with battery development in general. Over the past century, battery technology has continuously advanced toward the single goal of increasing energy density.

All-solid-state batteries have higher energy density compared to lithium-ion batteries because the risks of explosion or fire have been eliminated, allowing for a reduction in safety-related components and replacing that space with active materials that increase battery capacity. This means better space utilization.

When electric vehicle battery modules and packs are configured with all-solid-state batteries, the reduction in the number of components allows for higher energy density per volume, making them ideal for electric vehicle batteries that require increased capacity.

The second reason for increasing electric vehicle battery capacity is autonomous driving. Autonomous driving requires real-time information exchange and command execution, causing a surge in power consumption within the vehicle.

For autonomous vehicles, the increase in battery capacity is essential due to the rapid rise in data usage. Software company Tuxera announced that autonomous vehicles use 11TB of data per day.

For reference, a semiconductor factory the size of four soccer fields generates 45TB of data daily, highlighting the enormous data volume generated by autonomous vehicles. As data processing increases, power consumption also rises.

◇Trends in All-Solid-State Battery Development

Although all-solid-state batteries are currently in the research and development stage, many automakers and battery/material companies are actively pursuing their development.

Toyota officially mentioned developing all-solid-state batteries in collaboration with the government and academia when it launched its next-generation battery research institute in 2008. German automaker Volkswagen plans to release electric vehicles equipped with all-solid-state batteries around 2025?2026 in cooperation with the U.S. company QuantumScape, and BMW is collaborating with Solid Power for similar plans.

Additionally, companies such as Murata, Hitachi, Kyocera, Toray, and Sumitomo Chemical are also developing all-solid-state batteries.

The industry expects that development at a level to replace lithium-ion batteries has not yet been achieved, and currently, due to low energy density, short lifespan, and high cost, mass production of all-solid-state batteries is anticipated only after 2025.

Samsung SDI, a leading global battery company, is also focusing on all-solid-state battery development. Besides its own projects, it is jointly developing all-solid-state battery technology in cooperation with Samsung Electronics’ Advanced Institute of Technology and its research center in Japan.

Since 2013, Samsung SDI has showcased mid- to long-term all-solid-state battery technologies at motor shows and battery exhibitions. Currently, it is in the element technology development stage, with commercialization expected after 2027.

Meanwhile, in March, Samsung Electronics’ Advanced Institute of Technology revealed research results on all-solid-state batteries capable of 800 km driving range on a single charge and over 1,000 charge-discharge cycles.

This research, which includes core technology that enhances the lifespan and safety of all-solid-state batteries while reducing their size by half, was published in the world-renowned academic journal Nature Energy.

For electric vehicles to travel farther and more safely, the development of all-solid-state batteries is essential. Although still in the early stages and facing many challenges before commercialization, global battery companies are dedicating all their efforts to future technology development.