The Toyota Bipolar NiMh hybrid pack was introduced in the Aqua in July 2021. This pack is smaller and lighter than the monopolar NiMh pack that has been used in variations across models and platforms.
In this innovative battery, a cathode is applied to one side of a metal component called a current collector and an anode to the other. Several of these structures, which are known as “bipolar electrodes,” are stacked together to form a battery. By having cathode and anode together in the current collector, batteries can be made smaller as they require fewer parts. In addition, the wider electrical path and simple structure reduce resistance within the battery, allowing large currents to flow quickly. This means that they can produce higher outputs compared to conventional nickel-metal hydride batteries.
Toyota Industries [2]
Bipolar Battery
The bipolar battery essentially moves the series connections inside the cell. This brings a number of advantages and significant challenges. The advantage is that you remove the need for external connections and some of the cell packaging. Reducing cost, package space and mass.
This is great, but do we have enough data to compare this to the monopolar NiMh battery pack?
- each cell gives 1.5 times the power output
- 1.4 times as many cells packed into the same volume
- 2x power output at pack level
This post has been built based on the support and sponsorship from: Thermo Fisher Scientific, Eatron Technologies, About:Energy, Quarto Technical Services and Alvatek.
At the moment there is not enough data to absolutely confirm the weight, power and package benefits.
References
- THE ALL-NEW LEXUS LBX, Lexus Media
- Toyota Industries establishes on-board battery production line at its new Ishihama Plant, Toyota Industries Corporation
- Bipolar Nickel Metal Hydride Battery, Patent JP2018028982A
See also: Toyota Batteries, Bipolar Battery