Heat exchange apparatus for cooling water of fuel cell and fuel cell system including the same

Abstract

A heat exchange apparatus for cooling water of a fuel cell includes a body, through which a cooling water pipe having cooling water flowing therethrough to be supplied to a fuel cell stack, passes; and a heat accumulator provided in an interior of the body and filled with a PCM heat accumulation material that exchanges heat with the cooling water. The body includes a medium space provided between the cooling water pipe and the heat accumulator such that the heat accumulator is spaced apart from the cooling water pipe. The PCM heat accumulation material exchanges heat with the cooling water by a medium of the medium space.

What is claimed is: 
     
         1 . A heat exchange apparatus for cooling water of a fuel cell, the heat exchange apparatus comprising:
 a body, through which a cooling water pipe having cooling water flowing therethrough to be supplied to a fuel cell stack passes; and   a heat accumulator provided in an interior of the body and filled with a PCM heat accumulation material that exchanges heat with the cooling water,   wherein the body includes a medium space provided between the cooling water pipe and the heat accumulator such that the heat accumulator is spaced apart from the cooling water pipe, and   wherein the PCM heat accumulation material exchanges heat with the cooling water by a medium of the medium space.   
     
     
         2 . The heat exchange apparatus of  claim 1 , wherein the PCM heat accumulation material is a material, a phase of which is changed at an operation temperature that is lower than a reference temperature due to a spacing interval between the heat accumulator and the cooling water pipe, the reference temperature is a phase change temperature required by the PCM heat accumulation material when the heat accumulator is located to contact the cooling water pipe. 
     
     
         3 . The heat exchange apparatus of  claim 2 , wherein the spacing interval is determined based on a heat transfer rate between the heat accumulator filled with the PCM heat accumulation material, a phase of which is changed at the operation temperature, and the cooling water pipe. 
     
     
         4 . The heat exchange apparatus of  claim 3 , wherein the body is provided such that the heat transfer rate between the heat accumulator and the cooling water pipe is adjusted by changing the spacing interval. 
     
     
         5 . The heat exchange apparatus of  claim 4 , wherein the spacing interval is changed such that a temperature of the cooling water discharged from the body is not more than a limit temperature corresponding to a maximum spacing interval and not less than the operation temperature. 
     
     
         6 . The heat exchange apparatus of  claim 4 , wherein the interior of the body includes a first area provided with the medium space,
 wherein the body includes a first outer wall part of an outer wall that defines the interior of the body, which first outer wall part is located to correspond to the first area and is elastically deformed, and   wherein the first outer wall part is elastically deformed as a pressure change of the medium space moves the heat accumulator in a first direction that is far away from the cooling water pipe or a second direction that is opposite to the first direction.   
     
     
         7 . The heat exchange apparatus of  claim 6 , further comprising:
 a pump configured to inject fluid into the medium space or suction fluid from the medium space to adjust an internal pressure of the medium space,   wherein the pump is an air compressor configured to supply air to the fuel cell stack.   
     
     
         8 . The heat exchange apparatus of  claim 4 , wherein the interior of the body includes a first area provided with the medium space, and a second area that is adjacent to the first area and provided with the heat accumulator,
 wherein the body includes a first outer wall part of an outer wall that defines the interior of the body, the first outer wall part located to correspond to the first area and elastically deformed, and a second outer wall part extending from the first outer wall part and located to correspond to the second area, and   wherein the first outer wall part is elastically deformed as a movement part connected to the second outer wall part moves the second outer wall part in a first direction moving away from the cooling water pipe or a second direction that is opposite to the first direction.   
     
     
         9 . The heat exchange apparatus of  claim 1 , wherein the heat accumulator includes:
 a heat transfer member surrounding at least a portion of the PCM heat accumulation material to transfer heat received from the cooling water to the PCM heat accumulation material by the medium of the medium space or receive heat, which is to be transferred to the cooling water, from the PCM heat accumulation material by the medium of the medium space.   
     
     
         10 . The heat exchange apparatus of  claim 9 , wherein the interior of the body includes a first area provided with the medium space, and a second area that is spaced apart from the cooling water pipe through the medium space and provided with the heat accumulator,
 wherein he heat transfer member includes:   a first member extending along a lengthwise direction of the cooling water pipe to differentiate the first area from the second area; and   a plurality of second members extending from the first member in a direction moving away from the cooling water pipe and spaced apart from each other in the lengthwise direction of the cooling water pipe, and   wherein the PCM heat accumulation material is filled in spaces defined by the first member and the second members in the second area.   
     
     
         11 . The heat exchange apparatus of  claim 1 , wherein the body has a tubular shape having a hollow, into which the cooling water pipe is inserted, and an inner surface spaced apart from an outer surface of the cooling water pipe to define the medium space in the hollow, and
 wherein the heat accumulator is provided in a lengthwise direction of the body along the inner surface of the body to be spaced apart from the cooling water pipe in a radial direction of the body.   
     
     
         12 . The heat exchange apparatus of  claim 11 , wherein the cooling water pipe is elastically deformed depending on a change in an internal pressure thereof, and
 wherein the spacing interval between the heat accumulator and the cooling water pipe is changed as the cooling water pipe expands or contracts in the radial direction of the body due to the change in the internal pressure of the cooling water pipe.   
     
     
         13 . The heat exchange apparatus of  claim 12 , further comprising:
 a body cover accommodating the body in an interior of the body cover and having an inner surface spaced apart from an outer surface of the body to provide a supplementary space between the body cover and the body,   wherein fluid in the medium space flows to the supplementary space through a connection passage connecting the medium space and the supplementary space as the cooling water pipe expands, and   wherein fluid in the supplementary space flows to the medium space through the connection passage as the cooling water pipe is contracted.   
     
     
         14 . The heat exchange apparatus of  claim 13 , wherein the body cover is elastically deformed as the fluid is introduced into or discharged from the supplementary space. 
     
     
         15 . A heat exchange apparatus for cooling water of a fuel cell, the heat exchange apparatus comprising:
 a body including a first pipe having a first hollow therein, and a second pipe having a second hollow therein, the second pipe provided in the first hollow of the first pipe to be spaced inwards apart from an inner surface of the first pipe; and   a heat accumulator provided in the second hollow of the second pipe and filled with a PCM heat accumulation material to exchange heat with cooling water, which flows along a flow space defined between the first pipe and the second pipe to be supplied to a fuel cell stack, and   wherein the body further includes:   a medium space provided between the second pipe and the heat accumulator such that the heat accumulator is located to be spaced inwards apart from the second pipe, and   wherein the PCM heat accumulation material exchanges heat with the cooling water by a medium of the medium space.   
     
     
         16 . The heat exchange apparatus of  claim 15 , wherein the second pipe is elastically deformed as an internal pressure of the flow space is changed, and
 wherein a spacing interval between the heat accumulator and the second pipe is changed as the second pipe expands or contracts in a radial direction of the second pipe.   
     
     
         17 . The heat exchange apparatus of  claim 16 , further comprising:
 a body cover accommodating the body in an interior of the body cover and having an inner surface spaced apart from an outer surface of the body to provide a supplementary space between the body cover and the body,   wherein fluid in the medium space flows to the supplementary space through a connection passage connecting the medium space and the supplementary space as the second pipe is contracted,   wherein fluid in the supplementary space flows to the medium space through the connection passage as the second pipe expands, and   wherein the body cover is elastically deformed as the fluid is introduced into or discharged from the supplementary space.   
     
     
         18 . A fuel cell system comprising:
 a fuel cell stack including a fuel electrode and an air electrode; and   a cooling water pipe configured to supply cooling water to the fuel cell stack; and   a heat exchanger configured to exchange heat with the cooling water in an interior of the heat exchanger,   wherein the heat exchanger includes:   a body, through which the cooling water pipe passes; and   a heat accumulator provided in an interior of the body and filled with a PCM heat accumulation material that is to exchange heat with the cooling water,   wherein the body further includes:   a medium space provided between the cooling water pipe and the heat accumulator such that the heat accumulator is located to be spaced apart from the cooling water pipe, and   wherein the PCM heat accumulation material exchanges heat with the cooling water by a medium of the medium space.   
     
     
         19 . The fuel cell system of  claim 18 , wherein the body is provided such that a heat transfer rate between the heat accumulator and the cooling water pipe is adjusted by changing a spacing interval between the heat accumulator and the cooling water pipe. 
     
     
         20 . The fuel cell system of  claim 19 , further comprising:
 an adjustment device configured to adjust the spacing interval; and   a controller configured to control the adjustment device,   wherein the controller adjusts the spacing interval through the adjustment device such that the cooling water discharged from the body is at a target temperature between a first temperature that is a temperature of the cooling water discharged from the body when the spacing interval is changed to a maximum value, and a second temperature that is lower than the first temperature.