Method for controlling hole size and porosity of cement-based bipolar plate

Abstract

The invention relates to a method for controlling a hole size and a porosity of a cement-based bipolar plate. The method for controlling the hole size and the porosity of the cement-based bipolar plate is characterized by comprising the following steps of: 1) grinding and sieving a graphite conductive filler, so as to obtain two graphite conductive fillers with different sizes; 2) drying the graphite conductive fillers in a dried condition according to a weight ratio of graphite with a large size to graphite with a small size of 4 to 1; 3) mixing the mixed graphite and cement in a ball milling machine in the dried condition, wherein a weight ratio of the mixed graphite and the cement is 6 to 4; and stirring mixture with de-ionized water and hydrating the cement at a constant temperature for 30-120 min, wherein the weight ratio of the cement to the water is 1:(0.2-0.4); 4) forming through compression molding, wherein a compression molding pressure is 10-15 MPa, and a compression molding time is 10-30 minutes; and 5) maintaining, so as to obtain the cement-based bipolar plate with different apertures and porosities. With the adoption of the method provided by the invention, the size of an inner hole and the porosity of the prepared bipolar plate can be controlled well; the hole diameter is dozens to hundreds of nanometers; and the porosity is 7V%-15V%.

Description

technical field [0001] The invention relates to a method for controlling the pore size and porosity of a cement-based bipolar plate for a proton exchange membrane fuel cell. Background technique [0002] Proton exchange membrane fuel cell (PEMFC) is considered as the third generation power system after steam engine and internal combustion engine. At present, for the kilowatt-level PEMFC stack, the external humidification auxiliary system is mainly used to humidify the reaction gas entering the PEMFC to maintain the water content of the proton exchange membrane. This humidification method is very effective and can be adjusted according to the output power of the PEMFC. Adjust the amount of water for humidification. However, these external humidification auxiliary systems complicate the entire power generation system, increase system cost, weight and volume, and increase the complexity of stack assembly when PEMFC is applied to electric vehicles as a power source. Therefore,...

AI Technical Summary

Problems solved by technology

However, the detailed preparation process of the porous bipolar plate is unknown, and it is estimated that it still depends on the modification of the traditional expensive machined graphite plate. The gas flow field of the graphite plate needs to be machined, which leads to its high price, which is also hindering the development of fuel cells. One of the obstacles to commercialization