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Technology File - Safety Technology

FC Stack

Toyota First1<Volume power density> Global Top Level2Column

Hundreds of cells are stacked, creating a small power plant.

The fuel cell (FC) stack is a power generating device that produces electricity by using a chemical reaction between hydrogen and oxygen in the air. Hydrogen is supplied to a negative electrode (anode) and air (oxygen) is supplied to positive electrode (cathode), generating electric power in an opposite reaction of electrolysis. The FC stack comprises hundreds of stacked components called cells. Each cell consists of a membrane electrode assembly (MEA), which is a solid polymer electrolyte membrane coated with catalyst on both sides (electrodes), sandwiched between separators. The voltage of a single cell is less than 1 V, and consequently, the voltage is increased by stacking hundreds of cells in series. The cells are stacked in this manner to create a single FC stack, also known as a fuel cell stack (a “fuel cell” generally refers to an FC stack or fuel cell stack).

Innovations to the cell flow channel structure and electrodes of the Mirai FC stack produce a power density of 3.1 kW/L, which is at that world’s highest level. This enabled miniaturization of the FC stack, making it possible to install the FC stack below the floor of a sedan and create a spacious vehicle interior.

  1. As of November 2014.
  2. As of November 2014. According to Toyota Motor Corporation.
FC Stack
Main specifications of the Mirai FC stack
Maximum output 114 kW (155PS)
Volume power density 3.1 kW/L (global top level)
Number of cells in one stack 370 cells (single-line stacking)

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Specifications may differ depending on country, region, or model.