Flexible composite graphite bipolar plate production line

Bipolar plate, also called collector plate, is one of the important parts of fuel cell. It has the following functions and properties: separating fuel and oxidant, preventing gas transmission; collecting and conducting current with high conductivity; designed and processed flow channel, which can evenly distribute the gas to the reaction layer of the electrode for the electrode reaction; able to discharge heat and keep the temperature field of the cell uniform; corrosion resistant; shock and vibration resistant; thin thickness; light weight; and at the same time, low cost, easy to be machined and suitable for batch manufacturing.

The function of the bipolar plate (also known as the spacer) is to provide gas flow paths to prevent hydrogen and oxygen in the gas chamber of the battery from cascading, and to establish current paths between the cathode and anode connected in series. Under the premise of maintaining a certain mechanical strength and good gas barrier, the thickness of the bipolar plate should be as thin as possible to reduce the resistance to current and heat conduction.

Bipolar plate materials can be roughly divided into 3 categories: carbon materials, metal materials and composite materials of metal and carbon.

(1) Carbonaceous materials. Carbonaceous materials include graphite, moulded carbon materials and expanded (flexible) graphite. Conventional bipolar plates are made of dense graphite, which is mechanically processed to make gas flow channels. -Graphite bipolar plates are chemically stable and have low contact resistance with MEA.

(2) Metal materials. Metal materials such as aluminium, nickel, titanium and stainless steel can be used to make bipolar plates. Metal bipolar plates are easy to process, can be manufactured in bulk, low cost, thin thickness, and high volume specific power and specific energy of the battery.

(3) Composite materials. If the contact resistance between the bipolar plate and the MEA is large, the ohmic resistance produces much polarisation loss and the operating efficiency decreases. Among the various bipolar plate materials in common use, graphite material has the lowest contact resistance, and stainless steel and titanium have non-conductive oxide film formed on their surfaces to increase the contact resistance.

CHINA GWELL after continuous exploration and development of bipolar plate production equipment, the equipment produced bipolar plate quality, high carbon powder content, high conductivity, the equipment itself is stable, high degree of automation.

Production process: through the mixer will be plastic particles, carbon powder and related additives mixed evenly, and then use the feeder will be mixed raw materials conveyed to the extruder, the extruder melt through the mould extrusion bipolar plate, and then use the three-roller calender for cooling and shaping, and then the use of the oven for tempering to obtain a good thickness uniformity of the bipolar plate, in the use of other related equipment on the plate for a series of treatments such as trimming, de-static etc., and finally the use of winding After using other related equipment to carry out a series of processing of the plate, such as trimming, de-static, etc., and finally use the winding machine to wind up the rolls.