[2025 Green Mobility] Hyundai Toyota Maximizes Efficiency of 'Bipolar' Battery

by Woo Sooyoun

Published 12 Feb.2025 07:30(KST)

Toyota's Bipolar Battery Technology
Maximizing Fuel Efficiency and Advancing Carbon Neutrality

Toyota Motor Corporation has been continuously striving for carbon neutrality since the launch of the world's first mass-produced hybrid model, the Prius, in 1997. The Toyota Crown and Lexus RX models released domestically in 2023 are equipped with bipolar battery technology to maximize fuel efficiency.

Toyota Bipolar Battery Module Structure (Provided by Toyota Motor Korea)

Bipolar batteries break away from the traditional cell-based configuration by utilizing both sides of the electrode plate to construct the battery, resulting in reduced volume and increased output. Conventional batteries connect cells in series, which limits current flow and output while increasing volume.

However, bipolar batteries apply the positive electrode on one side of a single cell and the negative electrode on the other, allowing current to flow freely and enabling a more compact battery size.

Toyota Bipolar Battery Module Structure (Provided by Toyota Motor Korea)

Currently, bipolar technology is applied only to nickel-metal hydride batteries, but a representative from Toyota Korea explained that applying it to lithium-ion batteries could achieve even higher integration density.

Bipolar technology reduces battery volume, making packaging easier, and lowers electrical resistance in the battery, enabling high output. Additionally, increased current freedom allows for higher levels of regenerative energy recovery, contributing to improved fuel economy.

Toyota has applied bipolar technology to its latest hybrid vehicles. The Toyota Crown, a mid-to-large hybrid sedan, is equipped with a 2.4ℓ dual boost hybrid system and a 2.5ℓ series-parallel hybrid system, both utilizing batteries with bipolar technology. This technology is also applied to Lexus’s mid-to-large sport utility vehicles (SUVs), the RX 350h and RX 500h F SPORT Performance hybrids.

Crown 2.4 Liter Dual Boost Hybrid (Provided by Korea Toyota Motor)

In Toyota’s own tests with the compact hatchback Aqua, the conventional lithium-ion battery showed about 3% better fuel economy than Toyota’s bipolar nickel-metal hydride battery. However, when the curb weight increased by about 10 kg, the bipolar nickel-metal hydride battery measured approximately 3% higher fuel economy.

Toyota continues to practice carbon neutrality based on the group’s goal of "protecting the beautiful earth and enriching the lives of people worldwide."

Toyota aims to reduce the average carbon dioxide (CO2) emissions of vehicles sold worldwide by 33% by 2030 and by more than 50% by 2035 compared to 2019 levels. To achieve this, Toyota plans to offer customers diverse options centered on the "Multi Pathway" strategy, which considers future energy supply and demand and regional conditions worldwide.