Bipolar plate and a fuel cell stack comprising same

Abstract

Provided are a bipolar plate and a fuel cell stack comprising the same. The invention relates to a bipolar plate (10) for a fuel cell stack. The bipolar plate (10) has two profiled separator plates (12, 14), which each have an active region (16) and two distributor regions (18, 20) for supplying and removing reaction gases and coolant to or from the active region (16), wherein the separator plates(12, 14) are designed and arranged one over the other in such a way that the bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, which connect ports (22, 24,26) for reaction gases and coolant of both distributor regions (18, 20) to each other. In the assembled fuel cell stack, the channels (28, 30) for the reaction gases are each bounded by a surface ofa separator plate (12, 14) and a surface of a gas diffusion layer (58). According to the invention, the bipolar plate (10) has an impermeable first separating plate (38), which divides the channels (28) for a reaction gas into two volume regions in an inlet region (40) of the active region (16) and extends in the flow direction (42) of the reaction gas, wherein only one volume region of the channel (28) is adjacent to the gas diffusion layer (58). The invention further relates to a fuel cell stack having such bipolar plates (10) and to a fuel cell system having a fuel cell stack according to the invention.

Description

technical field [0001] The invention relates to a bipolar plate for a fuel cell stack, the bipolar plates each having two profiled diaphragm plates each having an active zone; and two distributed zone for directing reaction gas and coolant to or from the active zone, wherein the diaphragm plates are constructed and arranged superimposed such that the respective bipolar plates have separate channels for reaction gas and coolant , the ports of the channels for the reaction gas and the coolant of the two distribution zones are connected to each other, wherein the channels for the reaction gas are bounded by the surface of the diaphragm plate and the surface of the gas diffusion layer, respectively. Furthermore, the invention also relates to a fuel cell stack with such a bipolar plate and a fuel cell system with such a fuel cell stack. Background technique [0002] Fuel cells use the chemical conversion of fuel and oxygen into water to generate electricity. For this purpose, t...

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Problems solved by technology

[0005] In order to control the water supply with respect to the reaction gases in the bipolar plates to increase the power density, efficiency and service life of the fuel cell, inter alia WO 2012 / 143781 A1 (Toyota Group (Toyota)) and US 20090197134 A1 (Daimler Group (Daimler)) to introduce a plurality of metal strips made of titanium into the channel for the reaction gas to be wetted, however this is expensive and also expensive in production, since these metal strips may Difficult to fix and difficult to position; or introduce a perforated metal plate into the channel, which is also expensive and expensive to manufacture

Furthermore, these solutions cannot be applied in combination with bipolar plates of graphite

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