Fuel cell thermal management system with phase change heat storage and preheating functions

Abstract

The invention discloses a fuel cell thermal management system with phase change heat storage and preheating functions. The fuel cell thermal management system comprises a heat pipe heat exchange part,a liquid path preheating loop, a liquid path heating loop, a gas path preheating loop and a gas path heating loop, wherein the heat pipe heat exchange part is embedded into a heat pipe in a polar plate to exchange heat with an external liquid path, a first phase-change heat exchanger is connected with a liquid path, a second phase-change heat exchanger is simultaneously connected with a gas pathand the liquid path, the liquid path preheating loop heats the liquid path through the first phase change heat exchanger, the gas path preheating loop heats the gas path through the second phase change heat exchanger to jointly preheat a fuel cell, waste heat of a fuel cell in the liquid path heating loop accumulates heat for the phase change heat exchanger or heats a lithium battery and a passenger compartment, the gas path heating loop indirectly heats inlet gas through cooling liquid. The fuel cell thermal management system is advantaged in that the waste heat of the fuel cell can be storedin the phase change heat exchanger and used for preheating the fuel cell through a liquid path and a gas path or for heat preservation of the fuel cell, in addition, the waste heat of the fuel cell can heat intake air, a lithium battery or a passenger compartment, and the energy utilization rate is increased.

Description

technical field [0001] The invention relates to a thermal management system of a hydrogen fuel cell for vehicles, in particular to a thermal management system of a fuel cell with phase change heat storage and preheating functions. Background technique [0002] The proton exchange membrane fuel cell directly converts chemical energy into electrical energy without going through the heat engine process and is not limited by the Carnot cycle. The energy conversion efficiency can be as high as 40% to 60%. The advantages of fast load response and high energy conversion efficiency have broad application prospects in electric vehicles; the optimum operating temperature range of hydrogen fuel cells should be kept at 70-80°C, but at low temperatures, especially below 0°C in cold winter, it must be considered Low-temperature storage and cold start problems. When the liquid water inside the fuel cell freezes, the volume expands and when it fuses, uneven stress will be generated, causing...

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Problems solved by technology

[0002] The proton exchange membrane fuel cell directly converts chemical energy into electrical energy without going through the heat engine process and is not limited by the Carnot cycle. The energy conversion efficiency can be as high as 40% to 60%. The advantages of fast load response and high energy conversion efficiency have broad application prospects in electric vehicles; the optimum operating temperature range of hydrogen fuel cells should be kept at 70-80°C, but at low temperatures, especially below 0°C in cold winter, it must be considered Low-temperature storage and cold start problems. When the liquid water inside the fuel cell freezes, the volume expands and when it fuses, uneven stress will be generated, causing damage to the battery material, resulting in a decline in fuel cell performance and service life. Therefore, low temperature cold start should be achieved as soon as possible. Normal operating temperature is also an important factor limiting the application range of fuel cells;

[0003] In the existing technology, fuel cell vehicles generally use PTC water heating or air heating to provide warm air in winter, which will consume a lot of electric energy and affect the battery life of the vehicle, and the waste heat during the operation of the fuel cell is passed through the radiator and exhaust gas. The exhaust is not effectively used, which affects the energy utilization rate of the whole vehicle; fuel cells are generally used in combination with lithium battery packs to form a hybrid power system, and the optimal operating temperature of lithium batteries is 25 ° C ~ 40 ° C, and low temperature in winter also affects lithium Battery performance and life have a great impact. Lithium batteries also need to be preheated to reach the normal operating temperature, but the existing technology also uses PTC water heating, which requires more power consumption

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