Patent Publication Number: US-2010112419-A1

Title: Battery temperature controller for electric vehicle using thermoelectric semiconductor

Description:
TECHNICAL FIELD 
     The present invention relates to a device for controlling the temperature of batteries for electric vehicles (including hybrid vehicles). 
     More particularly, the present invention relates to a device for controlling the temperature of batteries for electric vehicles, which can cool batteries, which are mounted in an electric vehicle, using thermoelectric semiconductor elements. 
     BACKGROUND ART 
     Generally, vehicles are classified into steam vehicles, internal combustion engine vehicles, and electric vehicles according to the type of power source. Of the vehicles, the electric vehicle is currently attracting more attention as a means for solving the problem of serious atmospheric pollution due to the exhaust gas of internal combustion engine vehicles and the problem of increased fuel expenses due to the high price of oil. 
     Such an electric vehicle is a device that uses electricity as its power source, and is moved by operating an electric motor using electrical energy, unlike a general vehicle, which moves using the energy that is obtained by burning petroleum-based fuel in an internal combustion engine. 
     Furthermore, the electric vehicle generates hardly any noise or vibrations, and does not discharge any exhaust gas, so that it does not cause any smell and does not pollute the atmosphere. 
     The electric vehicle is designed to be moved based on the principle of driving wheels by rotating an electric motor using electrical energy. Battery energy having a high-voltage characteristic is necessarily required in order to move the vehicle. 
     However, currently, a high battery energy, which is sufficient to operate an electric vehicle, cannot be realized using only a single battery, and thus a plurality of batteries must be connected in series or in parallel not only to realize a high voltage but also to maintain a long lifespan. 
     An entity in which a plurality of batteries is aggregated and held is called a battery pack. In practice, the battery pack is fastened to a tray having a box shape, and is then mounted in an electric vehicle. 
     The performance and lifespan of the above-described batteries are maintained by appropriately radiating the high heat that is generated upon operation. For example, the batteries are cooled using air inside or outside a vehicle. When air inside or outside a vehicle is used as described above, a delay occurs until the temperature of the batteries reaches a required appropriate temperature because air outside the vehicle can be anywhere within wide temperature and humidity ranges. Accordingly, a problem occurs in that the performance of the batteries is lowered until the temperature of the batteries falls within a normal temperature range. 
       FIG. 1  is a diagram showing the construction of a prior art battery cooling device. 
     Referring to  FIG. 1 , the battery cooling device includes a plurality of batteries  1 , which are mounted in a battery tray  2  and are spaced apart from each other at regular intervals, the battery tray  2 , which is configured such that the plurality of batteries  1  is mounted therein, and a cooling fan  3 , which is configured to discharge heat, which is radiated from the batteries  1 , at one side of the battery tray  2 . 
     In the above-described battery cooling device, the cooling fan  3  is mounted in the battery tray  2 , in which the plurality of batteries  1  is mounted, and an auxiliary battery  4  is connected to the cooling fan  3  via a starting switch  5  and a battery controller  6 . 
     Furthermore, a temperature sensor  7  is mounted in the battery tray  2 . A relay is provided in the battery controller  6 , and is configured to be controlled in response to a detection signal from the temperature sensor  7  and to interrupt the supply of power to the cooling fan  3  or supply the power to the cooling fan  3 . 
     The prior art cooling device, described above, causes the battery controller  6  to maintain an appropriate temperature according to the detection signal from the temperature sensor  7  when the starting switch  5  is merely turned on, and can control an increase in the temperature of the batteries at room temperature to some extent. However, the prior art cooling device cannot actively response to variations in the temperature conditions outside a vehicle, that is, low or high temperature conditions. This is a major cause of reduction in the performance of the batteries. 
     In order to solve the above-described problems occurring in the prior art, a method of supplying the exhaust gas of a vehicle, or cool air, which is obtained through heat exchange in an air-conditioner, to batteries is used. However, this method not only makes the device complicated but also makes it difficult to control, and thus the manufacturing cost of each vehicle is increased. 
     Furthermore, there is a method of thermally connecting a heat sink and the electrodes of batteries to each other and heating or cooling the heat sink. However, this method is problematic in that it is difficult to select and use the medium that is used to heat or cool the heat sink and in that a separate heat source must be provided. 
     Based on semiconductor cooling and heating elements, there is a method of attaching thermoelectric cooling elements to the respective outer surfaces of batteries and performing heating and cooling using separate heat transfer media. In this case, there is a problem in that the heat generated in high-capacity electric vehicle batteries cannot be cooled to an appropriate temperature due to the amount of heat energy that is transmitted to the batteries, depending on the transfer media, and due to a transfer time delay. Furthermore, the main body casing of each battery is generally made of thick plastic material, rather than metal, so that individual batteries cannot be effectively cooled due to the low thermal conductivity thereof, even if the main body casing is cooled. In the thermoelectric semiconductor elements, the outer surface thereof performs a heat radiating operation while a cooling surface is formed therein to perform a cooling operation. In the case where the operations are performed in reverse, reverse conditions are established. In the prior art, there is no cooling device for protecting semiconductor elements from the heat that is generated at the time of reversible reaction of elements, so that a problem occurs in that the elements are overheated and damaged upon practical application. 
     Unlike a general battery, such as a lead acid battery, an electric vehicle high-voltage battery provides a high voltage using a combination of a plurality of individual batteries. In the case where cooling is achieved through rapid heat transfer in this process, and the batteries are place at a low temperature, means for directly cooling and heating the individual batteries is required in order for the batteries to realize normal performance when rapidly heating. However, this problem cannot be solved using a method of cooling and heating the outer surface of a battery package. 
     DISCLOSURE  
     Technical Problem 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements, which enables the temperature of batteries to be maintained at an appropriate level using thermoelectric semiconductor elements. 
     Technical Solution 
     In order to solve the above-described problems, the present invention provides a device for controlling the temperature of batteries for electric vehicles, including: a thermoelectric semiconductor unit configured such that a portion thereof is exposed in a battery tray, thus radiating heat into a battery tray when input current flows in a first direction and absorbing heat inside the battery tray when the input current flows in a second direction; a thermoelectric semiconductor unit controller for causing the thermoelectric semiconductor unit to radiate heat by supplying the current, which flows in the first direction, to the thermoelectric semiconductor unit when a heat radiating control signal is input thereto, and causing the thermoelectric semiconductor unit to absorb heat by supplying the current, which flows in the second direction, to the thermoelectric semiconductor unit when a heat absorbing control signal is input thereto; a temperature sensor for detecting and outputting the temperature of the battery tray; and a battery controller for outputting the heat radiating control signal to the thermoelectric semiconductor unit controller when the temperature detected by the temperature sensor is lower than a predetermined value, and outputting the heat absorbing control signal to the thermoelectric semiconductor unit controller when the temperature detected by the temperature is equal to or higher than the predetermined value. 
     Advantageous Effects 
     The optimal temperature of the batteries is satisfied by automatically control the ON/OFF operation of the thermoelectric semiconductor elements and the direction of current according to conditions of use of the batteries, so that the batteries can realize their optimal performance. 
     Furthermore, according to the present invention, semiconductor cooling elements are used as a heat source for cooling and heating, so that noise and vibrations, which are generated by the prior art cooling device using a vehicle air-conditioner or heater or using a fan, can be reduced. 
     Furthermore, according to the present invention, the heat radiating operation and the heat absorbing operation can be controlled using a single thermoelectric semiconductor element, so that the temperature control device can be easily implemented. 
     Furthermore, according to the present invention, the heat insulating material, which surrounds the batteries, the inlet three-way valve, and the outlet three-way valve isolate the battery unit from the external air, so that the batteries can be protected from variation in the external temperature even when a vehicle is not traveling. 
     Furthermore, according to the present invention, the temperature of the battery unit can be more effectively, rapidly and accurately controlled when the temperature of the external air, having a wide temperature range and a large volume, is controlled according to the cooling flow that is formed in order of the heat insulating material, which surrounds the batteries, the inlet three-way valve, the outlet three-way valve and the thermoelectric semiconductor unit. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing the construction of a prior art battery cooling device; 
         FIG. 2  is a diagram showing the construction of a device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to an embodiment of the present invention; 
         FIG. 3  is a diagram showing the construction of a device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to another embodiment of the present invention; and 
         FIG. 4  is a diagram showing the internal construction of the thermoelectric semiconductor unit of  FIGS. 2 and 3 . 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS OF PRINCIPLE ELEMENTS 
       
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 11: battery 
               
               
                   
                 12: battery tray 
               
               
                   
                 13: cooling fan 
               
               
                   
                 14: auxiliary battery 
               
               
                   
                 15: switch 
               
               
                   
                 16: battery controller 
               
               
                   
                 17: temperature sensor 
               
               
                   
                 18: relay 
               
               
                   
                 19: thermoelectric semiconductor unit 
               
               
                   
                 20: thermoelectric semiconductor unit controller 
               
               
                   
                 21: thermoelectric semiconductor elements 
               
               
                   
                 22: heat radiating fins 
               
               
                   
                 23: control wire 
               
               
                   
                 30: inlet three-way valve 
               
               
                   
                 31: outlet three-way valve 
               
               
                   
                 32: heat insulating material 
               
               
                   
                 33: recirculation air pipe 
               
               
                   
                   
               
            
           
         
       
     
     BEST MODE 
     A device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to a preferred embodiment of the present invention is described in detail with reference to  FIG. 2  below. 
       FIG. 2  is a diagram showing the construction of the device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to an embodiment of the present invention. 
     Referring to  FIG. 2 , the device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to an embodiment of the present invention includes a plurality of batteries  11 , a battery tray  12 , a cooling fan  13 , an auxiliary battery  14 , a starting switch  15 , a battery controller  16 , a temperature sensor  17 , a relay  18 , a thermoelectric semiconductor unit  19 , and a thermoelectric semiconductor unit controller  20 . 
     The battery tray  12  is formed to have a hollow shape and, for example, is mounted on the bottom of an electric vehicle while containing the plurality of batteries  11  therein. This battery tray  12  is not limited thereto, and, for example, may be mounted in the front or rear portion or a vehicle. 
     The cooling fan  13  is located in the exhaust port of the battery tray  12 , and discharges heat, which is radiated from the batteries  11 , by sucking and discharging air inside the battery tray  12 . 
     The above-described cooling fan  13  is connected to the auxiliary battery  14  so that the heat, which is radiated from the batteries  11 , can be discharged to the outside via the starting switch  15  and the battery controller  16 . 
     The auxiliary battery  14  is used to supply low power to parts other than parts that are supplied with power from the batteries  11 , and is mounted outside the battery tray  12 . 
     Furthermore, the battery controller  16  causes power to be supplied to the cooling fan  13  or the thermoelectric semiconductor unit  19  by operating the relay  18  according to the temperature in the battery tray  12 . 
     The temperature sensor  17  is mounted in the battery tray  12 , and detects and outputs the temperature in the battery tray  12 . 
     The temperature sensor  17  transmits the detected temperature in the battery tray  12  to the battery controller  16 . 
     Furthermore, the battery controller  16  is configured to supply power to the cooling fan  13  and the thermoelectric semiconductor unit  19 , or to interrupt the supply of the power thereto, by controlling the operation of the relay  18  in response to the detection signal of the temperature sensor  17 . 
     Meanwhile, as shown in  FIG. 4 , the thermoelectric semiconductor unit  19  is located between the cooling fan  13  and the batteries  11 , and is provided with thermoelectric semiconductor elements  21  and heat radiating fins  22 . 
     Each of the thermoelectric semiconductor elements  21  has a structure in which two metals having different properties from each other are bonded to each other, and performs a heat radiating operation or a heat absorbing operation according to the direction of current (which is called the Peltier effect). The heat radiating or absorbing operation causes heat to be transmitted to the battery tray  12  via the heat radiating fins  22 . 
     The heat radiating fins  22  function to transmit heat to the battery tray  12  when the thermoelectric semiconductor elements  21  perform the heat radiating operation or the heat absorbing operation, and are configured such that the first ends thereof are attached to the thermoelectric semiconductor elements  21  and such that the second ends thereof are exposed into the exhaust port of the battery tray  11 . 
     Furthermore, the thermoelectric semiconductor unit controller  20  is located between the thermoelectric semiconductor elements  21  and the battery controller  16 , and supplies current to the themioelectric semiconductor elements  21  under the control of the battery controller  16 . 
     In this case, it is necessary for the thermoelectric semiconductor unit controller  20  to control the direction of the current that is transmitted to the thermoelectric semiconductor elements  21 . The reason for this is because the thermoelectric semiconductor elements  21  perform the heat radiating or absorbing operation according to the direction of the flowing current. 
     Meanwhile, the thermoelectric semiconductor unit controller  20  and the thermoelectric semiconductor elements  21  are connected to each other using control wires  23 . 
     The above-described temperature control device according to the present invention enables the battery controller  16  to maintain an appropriate temperature in response to the detection signal from the temperature sensor  17  when the starting switch  15  is merely turned on. 
     That is, the battery controller  16  receives the detected temperature from the temperature sensor  17 , which is located in the battery tray  12 . 
     Furthermore, if it is determined that the temperature received from the temperature sensor  17  is equal to or greater than a predetermined temperature, the battery controller  16  causes heat to be radiated by sequentially operating the relay  18  and the cooling fan  13 . 
     The battery controller  16  transmits a control signal to the thermoelectric semiconductor unit controller  20 , thus causing the heat absorbing operation to be performed by causing the thermoelectric semiconductor unit controller  20  to supply current to the thermoelectric semiconductor elements  21 . Subsequently, the heat radiating fins  22  transfer the heat in the battery tray  11  to the thermoelectric semiconductor elements  21  thanks to the heat absorbing operation of the thermoelectric semiconductor elements  21 , thus reducing the temperature of the battery tray  11 . 
     Meanwhile, if it is determined that the temperature received from the temperature sensor  17  is lower than the predetermined temperature, the battery controller  16  transmits a control signal to the thermoelectric semiconductor unit controller  20 , thus causing the heat radiating operation to be performed by causing the thermoelectric semiconductor unit controller  200  to supply current to the thermoelectric semiconductor elements  21 . Subsequently, the heat radiating fins  22  transmit the heat of the thermoelectric semiconductor elements  21  to the battery tray  11  thanks to the heat radiating operation of the thermoelectric semiconductor elements  11 , thus increasing the temperature in the battery tray  11 . 
     Meanwhile, a combination of the thermoelectric semiconductor elements and the cooling fan has been described herein, but a combination of the thermoelectric semiconductor elements and a heater may be made. 
     Mode for Invention 
     Meanwhile, a device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to another embodiment of the present invention is described in detail with reference to  FIG. 3  below. 
       FIG. 3  is a diagram showing the construction of the device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to another embodiment of the present invention. 
     Referring to  FIG. 3 , the device for controlling the temperature of batteries for electric vehicles using thermoelectric semiconductor elements according to the embodiment of the present invention includes a plurality of batteries  11 , a battery tray  12 , a cooling fan  13 , an auxiliary battery  14 , a starting switch  15 , a battery controller  16 , a temperature sensor  17 , a relay  18 , a thermoelectric semiconductor unit  19 , a thermoelectric semiconductor unit controller  20 , an inlet three-way valve  30 , an outlet three-way valve  31 , a heat insulating material  32 , and a recirculation air pipe  33 . 
     The battery tray  12  is formed to have a hollow shape and, for example, is mounted on the bottom of an electric vehicle and contains the plurality of batteries  11  therein. The battery tray  12  is not limited thereto, and, for example, may be mounted in the front or rear portion or a vehicle. 
     The cooling fan  13  is located in the intake or exhaust port of the battery tray  12 , and discharges heat, which is radiated from the batteries  11 , by sucking and discharging the air inside the battery tray  12 , or forcibly blowing air outside the vehicle into the battery tray  12 . 
     The above-described cooling fan  13  is connected to the auxiliary battery  14  so that the heat radiated from the batteries  11  can be discharged to the outside via the starting switch  15  and the battery controller  16 . 
     Furthermore, the inlet three-way valve  30  is used to change the direction of inlet air or to isolate the air inside the battery tray  12  and the air outside the battery tray  12  from each other, and is located in the intake port of the battery tray  12 . 
     Furthermore, the outlet three-way valve  31  is used to change the direction of outlet air or to isolate the air inside the battery tray  12  and the air outside the battery tray  12  from each other, and is located in the exhaust port of the battery tray  12 . 
     Furthermore, the heat insulating material  32  is located outside the battery tray  12 , so that the outer portion of the battery tray  12  can be thermally insulated. 
     The recirculation air pipe  33  is used as a circulation path for recirculating air inside the battery tray  12 , and is configured such that the inlet port thereof is connected to the inlet three-way valve  30  and such that the outlet port thereof is connected to the outlet three-way valve  31 . 
     The inlet three-way valve  30  and the outlet three-way valve  31 , described above, isolate the air inside the battery tray  12  and the air outside the battery tray  12  from each other in the state in which a vehicle system is not operated, by which the batteries  11  are little affected by the external temperature when a vehicle is exposed to low temperatures or high temperatures. 
     Furthermore, the recirculation air pipe  33  enables the heat, which is generated due to the use of the batteries  11  while the vehicle is traveling, to be recirculated in the battery tray  12  via the outlet three-way valve  31 -recirculation air pipe  33 -inlet three-way valve  31 -batteries  11 -cooling fan  13 -thermoelectric semiconductor unit  19  of the battery tray  12 . Accordingly, the heat inside a battery unit, which is generated while the vehicle is traveling, is cooled by the thermoelectric semiconductor unit and is rapidly supplied again, and thus air recirculation can be achieved such that the batteries can be used in a normal temperature range. 
     In this case, it is determined by the battery controller  16  whether it is necessary to suck the external air or to discharge the internal air through the switching operation of the inlet three-way valves  30  or the outlet three-way valve  31 . 
     The auxiliary battery  14  is used to supply low power to parts other than parts that are supplied with power from the batteries  11 , and is mounted outside the battery tray  12 . 
     Furthermore, the battery controller  16  causes power to be supplied to the cooling fan  13  or the thermoelectric semiconductor unit  19  by operating the relay  18  according to the temperature in the battery tray  12 . 
     The temperature sensor  17  is mounted in the battery tray  12 , and detects and outputs the temperature in the battery tray  12 . 
     The temperature sensor  17  transmits the detected temperature in the battery tray  12  to the battery controller  16 . 
     Furthermore, the battery controller  16  is configured to supply power to the cooling fan  13  and the thermoelectric semiconductor unit  19 , or to interrupt the supply of the power thereto, by controlling the operation of the relay  18  in response to the detection signal of the temperature sensor  17 . 
     Meanwhile, as shown in  FIG. 4 , the thermoelectric semiconductor unit  19  is located between the cooling fan  13  and the batteries  11 , and is provided with thermoelectric semiconductor elements  21  and heat radiating fins  22 . 
     Each of the thermoelectric semiconductor elements  21  has a structure in which two metals having different properties from each other are bonded to each other, and performs a heat radiating operation or a heat absorbing operation according to the direction of current (which is called the Peltier effect). The heat radiating or absorbing operation causes heat to be transmitted to the battery tray  12  via the heat radiating fins  22 . 
     The heat radiating fins  22  function to transmit heat to the battery tray  12  when the thermoelectric semiconductor elements  21  perform the heat radiating operation or the heat absorbing operation, and are configured such that the first ends thereof are attached to the thermoelectric semiconductor elements  21  and such that the second ends thereof are exposed in the exhaust port of the battery tray  11 . 
     Furthermore, the thermoelectric semiconductor unit controller  20  is located between the thermoelectric semiconductor elements  21  and the battery controller  16 , and supplies current to the thermoelectric semiconductor elements  21  under the control of the battery controller  16 . 
     In this case, it is necessary for the thermoelectric semiconductor unit controller  20  to control the direction of the current that is transmitted to the thermoelectric semiconductor elements  21 . The reason for this is because the thermoelectric semiconductor elements  21  perform the heat radiating or absorbing operation according to the direction of the flowing current. 
     Meanwhile, the thermoelectric semiconductor unit controller  20  and the thermoelectric semiconductor elements  21  are connected to each other using control wires  23 . 
     The above-described temperature control device according to the present invention enables the battery controller  16  to maintain an appropriate temperature in response to the detection signal from the temperature sensor  17  when the starting switch  15  is merely turned on. 
     That is, the battery controller  16  receives the detected temperature from the temperature sensor  17 , which is located in the battery tray  12 . 
     Furthermore, if it is determined that the temperature received from the temperature sensor  17  is equal to or higher than a predetermined temperature, the battery controller  16  causes heat to be radiated by sequentially operating the relay  18  and the cooling fan  13 . 
     The battery controller  16  transmits a control signal to the thermoelectric semiconductor unit controller  20 , thus causing the heat absorbing operation to be performed by causing the thermoelectric semiconductor unit controller  20  to supply current to the thermoelectric semiconductor elements  21 . Subsequently, the heat radiating fins  22  transfer heat in the battery tray  11  to the thermoelectric semiconductor elements  21  thanks to the heat absorbing operation of the thermoelectric semiconductor elements  21 , thus reducing the temperature of the battery tray  11 . 
     Meanwhile, if it is determined that the temperature received from the temperature sensor  17  is lower than the predetermined temperature, the battery controller  16  transmits a control signal to the thermoelectric semiconductor unit controller  20 , thus causing the heat radiating operation to be performed by causing the thermoelectric semiconductor unit controller  200  to supply current to the thermoelectric semiconductor elements  21 . Subsequently, the heat radiating fins  22  transmit the heat of thermoelectric semiconductor elements  21  to the battery tray  11  thanks to the heat radiating operation of the thermoelectric semiconductor elements  11 , thus increasing the temperature of the battery tray  11 . 
     Meanwhile, a combination of the thermoelectric semiconductor elements and the cooling fan has been described herein, but a combination of the thermoelectric semiconductor elements and a heater may be made.