Abstract:
The present invention provides an apparatus for controlling the temperature of a battery, which is capable of cooling a battery such as a lithium ion battery and the like by using the circulation of a liquid refrigerant and controlling the temperature of the battery through an endothermic reaction or an exothermic reaction caused by a phase transformation process of the corresponding supersaturated liquid refrigerant. To this end, the present invention comprises: at least one temperature sensor for sensing the temperature of a battery pack so as to generate a temperature detection signal; a refrigerant pipe which is extended between arrangement spaces of a plurality of battery cells included in the battery pack and circulates the supersaturated liquid refrigerant through the inside thereof; a refrigerant circulation driving unit which drives a cooling operation by circulating the supersaturated liquid refrigerant through the refrigerant pipe when the temperature of the battery pack rises; and a control unit for driving and controlling the refrigerant circulation driving unit when the rise in the temperature of the battery pack is detected according to a temperature detection signal received from at least one temperature sensor.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an apparatus for controlling battery temperature, and, more particularly, to an apparatus for controlling battery temperature capable of controlling temperature of a battery through endothermic reaction or exothermic reaction in phase transformation of a supersaturated liquid refrigerant and through cooling by the supersaturated liquid refrigerant. 
       BACKGROUND ART 
       [0002]    Recently, as environmental destruction and pollution problems become more critical, to solve these, research and development of alternative energy sources is underway all over the world. As part of these developments of alternative energy sources, development of battery systems is ongoing. 
         [0003]    As a typical battery system, a lithium ion (Li-ion) battery has been researched and developed and put to practical use. A lithium ion battery is fabricated by introducing a non-aqueous electrolyte containing a lithium salt and an organic solvent into an electrode structure composed of a cathode, an anode, and a separator interposed between the cathode and the anode, and generates electrical energy through oxidation and reduction upon intercalation/deintercalation of lithium ions into/from the cathode and the anode. 
         [0004]    Such a lithium ion battery uses carbonate organic solvents, particularly, alkylene carbonates such as propylene carbonate or ethylene carbonate as an organic solvent constituting a non-aqueous electrolyte, and is used as a battery for electric vehicles such as hybrid automobiles, plug-in hybrid automobiles, electric automobiles, and the like. 
         [0005]    One example of the related art is disclosed in Korean Patent Publication No. 10-2012-0050799 (published on May 21, 2012) entitled “Battery cell assembly having heat sink attached thereto”. 
       DISCLOSURE 
     Technical Problem 
       [0006]    When conventional lithium ion batteries are used in vehicles such as electric vehicles, the battery is required to maintain a certain temperature or to be cooled to an appropriate temperature in order to achieve normal supply of battery power in extreme regions, such as extremely cold regions or extremely hot regions. 
         [0007]    Generally, cooling methods for lithium ion batteries include water cooling and air cooling. Despite having relatively high cooling efficiency, a water cooling system has problems of difficulty in weight reduction and inconvenience of device replacement due to a non-detachable structure thereof. On the other hand, despite good replaceability, an air cooling system has difficulty in cooling to a desired temperature, thereby causing deterioration in heat control efficiency. 
         [0008]    Moreover, in order to maintain efficiency of the battery at a constant level in an extremely cold region or in winter, there is a need for a separate preheater such as a thermoelectric element, which requires separate additional power and has poor replaceability while causing inevitable increase in weight and volume. 
         [0009]    Further, when a vehicle such as an electric vehicle is provided with both a preheater and a cooler, weight and volume of the vehicle are unavoidably increased, thereby causing deterioration in energy efficiency. 
         [0010]    The present invention has been conceived to solve such problems in the art and it is an object of the present invention to provide an apparatus for controlling battery temperature, which is capable of cooling a battery such as a lithium ion battery by circulating a liquid refrigerant and controlling temperature of the battery through an endothermic reaction or an exothermic reaction in phase transformation of the supersaturated liquid refrigerant. 
         [0011]    It is another object of the present invention to allow functions of preheating or cooling a battery such as a lithium ion battery to be achieved using the same supersaturated liquid refrigerant whether in cold seasons or hot seasons and whether in cold areas or hot areas, thereby improving charge/discharge efficiency of the battery. 
         [0012]    It is a further object of the present invention to allow temperature of a battery such as a lithium ion battery to be maintained at a level suitable for operation of the battery, while extending lifespan of the battery. 
       Technical Solution 
       [0013]    In accordance with one aspect of the present invention, an apparatus for controlling battery temperature includes: at least one temperature sensor sensing temperature of a battery pack and generating a temperature sensing signal; a refrigerant pipe extending between plural battery cells contained in the battery pack to allow a supersaturated liquid refrigerant to be circulated therethrough; a refrigerant circulation driving unit circulating the supersaturated liquid refrigerant through the refrigerant pipe to cool the battery pack upon increase in temperature of the battery pack; and a controller controlling the refrigerant circulation driving unit to operate when detecting increase in temperature of the battery pack in response to the temperature sensing signal from the at least one temperature sensor. 
         [0014]    The at least one temperature sensor may be provided in plural number to individually detect respective temperatures of the plural battery cells, and the controller may calculate an average temperature value from plural respective temperature sensing signals generated by the plurality of temperature sensors and detect increase in temperature of the battery pack based on the average temperature value. 
         [0015]    The apparatus may further include: inlet side and outlet side on/off valves placed at pipe inlet and outlet sides of connections between the refrigerant circulation driving unit and the refrigerant pipe, respectively; and a plurality of on-off valves respectively placed at entry sides of extensions of the refrigerant pipe extending between the plural battery cells. 
         [0016]    The controller may set multiple successive modes based on temperature obtained from the temperature sensing signal from the at least one temperature sensor and controls opening/closing of the inlet side on/off valve, the outlet side on/off valve, and the plurality of on/off valves in a differential manner according to each of the multiple modes. 
         [0017]    The supersaturated liquid refrigerant may include at least one of a sodium acetate (CH 3 COONa) solution and a sodium thiosulfate (Na 3 AsO 3 ) solution. 
         [0018]    In accordance with another aspect of the present invention, an apparatus for controlling battery temperature includes: at least one temperature sensor sensing a temperature of a battery pack and generating a temperature sensing signal; a refrigerant pipe extending between plural battery cells contained in the battery pack to allow a supersaturated liquid refrigerant to be circulated therethrough; a refrigerant circulation driving unit transmitting the supersaturated liquid refrigerant to an inside of the refrigerant pipe to preheat the battery pack through phase transformation of the supersaturated liquid refrigerant upon drop in temperature of the battery pack; an electric shock applying unit applying an electric shock voltage to the refrigerant pipe to generate static electricity by which the supersaturated liquid refrigerant is transformed from a liquid phase to a solid phase to generate heat; and a controller controlling the refrigerant circulation driving unit to operate and controlling the electric shock applying unit to generate the electric shock voltage upon detecting decrease in temperature of the battery pack in response to the temperature sensing signal from the at least one temperature sensor. 
         [0019]    The at least one temperature sensor may be provided in plural number to individually detect respective temperatures of the plural battery cells, and the controller may calculate an average temperature value from plural temperature sensing signals generated by the plurality of temperature sensors and detect decrease in temperature of the battery pack based on the average temperature value. 
         [0020]    The apparatus may further include: inlet side and outlet side on/off valves placed at pipe inlet and outlet sides of connections between the refrigerant circulation driving unit and the refrigerant pipe, respectively; and a plurality of on/off valves respectively placed at entry sides of extensions of the refrigerant pipe extending between the plural battery cells. 
         [0021]    The controller may set multiple successive modes based on temperature obtained from the temperature sensing signal from the at least one temperature sensor and controls opening/closing of the inlet side valve, the outlet side valve, and the plural on-off valves in a differential manner according to each of the multiple modes. 
         [0022]    The supersaturated liquid refrigerant may include one of a sodium acetate (CH 3 COONa) solution and a sodium thiosulfate (Na 3 AsO 3 ) solution. 
         [0023]    The refrigerant pipe may be provided therein with heating wires along extensions of the pipe. 
       Advantageous Effects 
       [0024]    According to the present invention, temperature of a battery such as a lithium ion battery can be adjusted through endothermic reaction or exothermic reaction in phase-transformation of a supersaturated liquid refrigerant or in cooling of the supersaturated liquid refrigerant in a liquid state, thereby eliminating a need for a preheating device that requires additional electric energy for preheating the battery, thereby enabling significant reduction in weight and volume while allowing self-preheating without additional energy loss. In addition, in terms of battery cooling functions, the apparatus for controlling battery temperature according to the present invention has merits of both water cooling and air cooling, thereby maximizing cooling efficiency. 
         [0025]    Further, according to the present invention, temperature of a battery can be adjusted to a proper level using the same supersaturated liquid refrigerant whether in cold seasons or hot seasons and in cold areas or hot areas, thereby improving charge/discharge efficiency of a battery while extending lifespan of the battery. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0026]      FIG. 1  is a view of an apparatus for controlling battery temperature according to one embodiment of the present invention, which is applied to a battery. 
           [0027]      FIG. 2  is a view showing configuration of the apparatus for controlling battery temperature according to the embodiment of the present invention. 
           [0028]      FIGS. 3   a  to  3   c  are views of a refrigerant circulation path through a refrigerant pipe in a battery pack for each mode in the apparatus for controlling battery temperature according to the embodiment of the present invention. 
           [0029]      FIG. 4  is a flowchart illustrating operation of the apparatus for controlling battery temperature according to the embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0031]    It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or size of components for descriptive convenience and clarity only. In addition, the terms used herein are defined by taking functions of the present invention into account and can be changed according to user or operator custom or intention. Therefore, definition of the terms should be made according to the overall disclosure set forth herein. 
       MODE FOR INVENTION 
       [0032]      FIG. 1  is a view of an apparatus for controlling battery temperature according to one embodiment of the invention, which is applied to a battery. 
         [0033]    Although the apparatus for controlling battery temperature according to this embodiment may also be used in various batteries other than a lithium ion battery, the present invention will be described by way of example wherein the apparatus is used in a lithium ion battery. 
         [0034]    Referring to  FIG. 1 , the apparatus for controlling battery temperature according to the embodiment includes first to sixth temperature sensors  120 ,  122 ,  124 ,  126 ,  128 ,  130 , a service plug  140 , a battery management system module (BMS module)  150 , a refrigerant pump  160 , a refrigerant reservoir  170 , a refrigerant pipe  180 , and first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 . 
         [0035]    The first to sixth temperature sensors  120 ,  122 ,  124 ,  126 ,  128 ,  130  are allocated to first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  constituting a lithium ion battery pack  100 , respectively, to detect temperature of the respective lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  and to generate first to sixth temperature sensing signals corresponding thereto. 
         [0036]    The refrigerant pump  160  is connected to an outlet of the refrigerant pipe  180  and performs pumping operation for circulating a supersaturated liquid refrigerant between the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  in the lithium ion battery pack  100  through the refrigerant pipe  180 . 
         [0037]    The refrigerant reservoir  170  is connected to an inlet of the refrigerant pipe  180  and serves to receive and store the supersaturated liquid refrigerant circulated between the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  through respective extensions of the refrigerant pipe  180 . 
         [0038]    The refrigerant pump  160  and the refrigerant reservoir  170  allow the supersaturated liquid refrigerant to be circulated through the refrigerant pipe  180 , and may be collectively referred to as a refrigerant circulation driving unit. 
         [0039]    The refrigerant pipe  180  is connected at the outlet thereof to the refrigerant pump  160  and connected at the inlet thereof to the refrigerant reservoir  170 , and extends between the first and sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  via the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  to allow the supersaturated liquid refrigerant to be circulated therethrough. 
         [0040]    The refrigerant pipe  180  is provided therein with heating wires along the extensions of the pipe, wherein the heating wire is used to preheat the lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  in cold seasons together with a main preheating operation through phase transformation of the supersaturated liquid refrigerant into a solid phase. 
         [0041]    Here, the supersaturated liquid refrigerant refers to a material which remains in a liquid phase in its normal state and undergoes phase transformation from a liquid phase to a solid phase, and is composed of one of a sodium acetate (CH 3 COONa) solution having a phase transformation temperature of 58° C. and a sodium thiosulfate (Na 3 AsO 3 ) solution having a phase transformation temperature of 48° C. 
         [0042]    The first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  individually perform opening/closing operation to control a flow of the supersaturated liquid refrigerant circulating through the refrigerant pipe  180 . 
         [0043]    The first on/off valve  182  is placed at the outlet side of the refrigerant pipe  180  connected to the refrigerant pump  160  and the second on/off valve  184  is placed at the inlet side of the refrigerant pipe  180  connected to the refrigerant reservoir  170 . 
         [0044]    In addition, the third on/off valve  186  is placed at an entry side of an extension of the refrigerant pipe  180  extending between the first lithium ion battery cell  102  and the second lithium ion battery cell  104 ; the fourth on/off valve  188  is placed at an entry side of an extension of the refrigerant pipe  180  extending between the second lithium ion battery cell  104  and the third lithium ion battery cell  106 ; and the fifth on/off valve  190  is placed at an entry side of an extension of the refrigerant pipe  180  extending between the third lithium ion battery cell  106  and the fourth lithium ion battery cell  108 . 
         [0045]    The sixth on/off valve  192  is placed at an entry side of an extension of the refrigerant pipe  180  extending between the fourth lithium ion battery cell  108  and the fifth lithium ion battery cell  110 , and the seventh on/off valve  194  is placed at an entry side of an extension of the refrigerant  180  extending between the fifth lithium ion battery cell  110  and the sixth lithium ion battery cell  112 . 
         [0046]    Next,  FIG. 2  is a view showing configuration of the apparatus for controlling battery temperature according to the embodiment of the invention. 
         [0047]    As shown in  FIG. 2 , the apparatus for controlling battery temperature according to this embodiment includes a controller  200 , a valve driving unit  210 , and an electric shock applying unit  220 . 
         [0048]    The controller  200  receives the first to sixth temperature sensing signals from the first to sixth temperature sensors  120 ,  122 ,  124 ,  126 ,  128 ,  130 , respectively, to detect temperature change of the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112 , and calculates an average temperature value from the first to sixth temperature sensing signals. When the average temperature value falls into a range in which operational efficiency of the battery is deteriorated, the controller controls the refrigerant pump  160  to operate while controlling the valve driving unit  210  to operate whereby the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  individually perform opening/closing operation depending upon temperature conditions, such that the supersaturated liquid refrigerant is circulated in a liquid phase to cool the lithium ion battery pack  100 , or the supersaturated liquid refrigerant is subjected to phase transformation into a solid phase through application of an electric shock voltage by the electric shock applying unit  220  to preheat the lithium ion battery pack  100 . 
         [0049]    On the other hand, when the average temperature value obtained from the first to sixth temperature sensing signals is less than or equal to a predetermined cold season-mode temperature, the controller  200  controls the refrigerant pump  160  to operate and allows the electric shock applying unit  220  to apply an electric shock voltage to the supersaturated liquid refrigerant in the refrigerant pipe  180  to preheat the lithium ion battery pack  100 , wherein opening/closing of the first to the seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  is controlled in a differential manner in proportion to degree of decrease in the average temperature value. 
         [0050]    In other words, the controller  200  sets multiple modes including a basic mode, an intermediate mode, and a lowest mode, divided according to a degree of decrease in the average temperature value. Specifically, when the average temperature value is less than or equal to the cold season-mode temperature, the controller initially sets the basic mode; when the average temperature value is less than or equal to the cold season-mode temperature and less than a mode setting temperature of the basic mode, the controller sets the intermediate mode; and when the average temperature value is less than a mode setting temperature of the intermediate mode, the controller sets the lowest mode. 
         [0051]    As shown in  FIG. 3   a , when the basic mode is set, the controller  200  opens only the first on/off valve  182  at the outlet side of the refrigerant pipe  180  connected to the refrigerant pump  160  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  connected to the refrigerant reservoir  170  among the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  such that a refrigerant circulation cycle is established only by an inner peripheral region of the lithium ion battery pack  100 . Further, the controller  200  allows the electric shock applying unit  220  to apply an electric shock voltage to the supersaturated liquid refrigerant such that heat generated through exothermic reaction in phase transformation of the supersaturated liquid refrigerant from a liquid phase to a solid phase is transmitted to the lithium ion battery pack  100  to preheat the battery pack. 
         [0052]    As shown in  FIG. 3   b , when the intermediate mode is set, the controller  200  opens the fourth on/off valve  188  at an entry side of an extension of the refrigerant pipe  180  extending between the second lithium ion battery cell  104  and the third lithium ion battery cell  106  and the sixth on/off valve  192  at an entry side of an extension of the refrigerant pipe  180  extending between the fourth lithium ion battery cell  108  and the fifth lithium ion battery cell  110  as well as the first on/off valve  182  at the outlet side of the refrigerant pipe  180  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  among the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 , such that a refrigerant circulation cycle is formed at only half of the entire battery sell section including the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112 . In addition, the controller  200  allows the electric shock applying unit  220  to apply an electric shock voltage to the supersaturated liquid refrigerant such that heat generated by the exothermic reaction upon phase transformation of the supersaturated liquid refrigerant from a liquid phase to a solid phase is transmitted to the lithium ion battery pack  100  to preheat the battery pack. 
         [0053]    As shown in  FIG. 3   c , when the lowest mode is set, the controller  200  opens all of the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 , such that a refrigerant circulation cycle is formed along all the extensions of the refrigerant pipe  180  for the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112 . In addition, the controller  200  allows the electric shock applying unit  220  to apply an electric shock voltage to the supersaturated liquid refrigerant such that heat generated by the exothermic reaction upon phase transformation of the supersaturated liquid refrigerant from a liquid phase to a solid phase is transmitted to the lithium ion battery pack  100  to preheat the battery pack. 
         [0054]    Further, when the average temperature value obtained from the first to sixth temperature sensing signals is higher than or equal to a predetermined cooling-mode temperature, the controller  200  controls the refrigerant pump  160  to operate to cool the lithium ion battery pack  100 , wherein opening/closing of the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  is controlled in a differential manner in proportion to degree of increase of the average temperature value. 
         [0055]    In other words, the controller  200  sets multiple modes including a basic mode, an intermediate mode, and a highest mode, divided according to the degree of increase in the average temperature value. Specifically, when the average temperature value is higher than or equal to the cooling-mode temperature, the controller initially sets the basic mode; when the average temperature value is higher than or equal to the cooling-mode temperature and exceeds a mode setting temperature of the basic mode, the controller sets the intermediate mode; and, when the average temperature value exceeds a mode setting temperature of the intermediate mode, the controller sets the highest mode. 
         [0056]    As shown in  FIG. 3   a , when the basic mode is set, the controller  200  opens only the first on/off valve  182  at the outlet side of the refrigerant pipe  180  connected to the refrigerant pump  160  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  connected to the refrigerant reservoir  170  among the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 , such that a refrigerant circulation cycle is established by only the inner peripheral region of the lithium ion battery pack  100 . Further, the controller  200  continuously drives the refrigerant pump  160  such that the supersaturated liquid refrigerant in the refrigerant pipe  180  is circulated to cool the lithium ion battery pack  100 , while remaining in liquid phase. 
         [0057]    As shown in  FIG. 3   b , when the intermediate mode is set, the controller  200  opens the fourth on/off valve  188  at the entry side of the extension of the refrigerant pipe  180  extending between the second lithium ion battery cell  104  and the third lithium ion battery  106  and the sixth on/off valve  192  at the entry side of the extension of the refrigerant pipe  180  extending between the fourth lithium ion battery cell  108  and the fifth lithium ion battery  110  as well as the first on/off valve  182  at the outlet side of the refrigerant pipe  180  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  among the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 , such that a refrigerant circulation cycle is formed at only half of the entire battery cell section including the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112 . Further, the controller  200  continuously drives the refrigerant pump  160  such that the supersaturated liquid refrigerant in the refrigerant pipe  180  is circulated to cool the lithium ion battery pack  100 , while remaining in liquid phase. 
         [0058]    As shown in  FIG. 3   c , when the highest mode is set, the controller  200  opens all of the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194 , such that a refrigerant circulation cycle is generated along all the extensions of the refrigerant pipe  180  for the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112 . Further, the controller  200  continuously drives the refrigerant pump  160  such that the supersaturated liquid refrigerant in the refrigerant pipe  180  is circulated to cool the lithium ion battery pack  100 , while remaining in liquid phase. 
         [0059]    The valve driving unit  210  individually opens or closes the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  under the control of the controller  200  in accordance with the basic mode, the intermediate mode, the lowest mode, or the highest mode. 
         [0060]    The electric shock applying unit  220  applies an electric shock voltage for generating static electricity to the refrigerant pipe  180  under the operational activation control of the controller  200 . 
         [0061]    Here, the electric shock voltage generated by the electric shock applying unit  220  only needs to have a voltage value capable of generating static electricity similar to static electricity typically generated under natural conditions. 
         [0062]    Next, operation of the apparatus for controlling battery temperature according to the present invention will be described in detail with reference to a flowchart in  FIG. 4 . 
         [0063]      FIG. 4  is a flowchart illustrating the operation of the apparatus for controlling battery temperature according to the present invention. 
         [0064]    First, in operation of a power consumption system such as an electric vehicle provided with the lithium ion battery pack  100 , when use of battery power is initiated (S 10 ), the controller  200  senses temperature conditions of the first to sixth lithium ion battery cells  102 ,  104 ,  106 ,  108 ,  110 ,  112  constituting the battery pack  100  through the respective temperature sensors  120 ,  122 ,  124 ,  126 ,  128 ,  130  (S 11 ). 
         [0065]    Then, the controller  200  converts the temperature sensing signals generated by the first to sixth temperature sensors  120 ,  122 ,  124 ,  126 ,  128 ,  130  into an average temperature value and determines whether the average temperature value is less than or equal to a predefined cold season-mode temperature (S 12 ). 
         [0066]    As a result, when it is determined that the average temperature value is less than or equal to the predefined cold season-mode temperature, the controller  200  determines whether the average temperature value is a temperature value corresponding to the basic mode (S 13 ). 
         [0067]    As a result, when it is determined that the average temperature value is a temperature value corresponding to the basic mode, as shown in  FIG. 3   a , the controller  200  opens only the first on/off valve  182  at the outlet side of the refrigerant pipe  180  connected to the refrigerant pump  160  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  connected to the refrigerant reservoir  170  among the first to seventh on/off valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  such that a refrigerant circulation cycle is established only by an inner peripheral region of the lithium ion battery pack  100 ; and drives the refrigerant pump  160  for the supersaturated liquid refrigerant to be moved along the circulation cycle of the refrigerant pipe  180  (S 14 ). 
         [0068]    On the other hand, when it is determined in S 13  that the average temperature value is not the temperature value corresponding to the basic mode, the controller  200  determines whether the average temperature value is a temperature value corresponding to the intermediate mode (S 15 ). 
         [0069]    As a result, when it is determined that the average temperature value is the temperature value corresponding to the intermediate mode, as shown in  FIG. 3   b , the controller  200  opens the fourth on/off valve  188  at the entry side of the extension of the refrigerant pipe  180  extending between the second lithium ion battery cell  104  and the third lithium ion battery cell  106  and the sixth on/off valve  192  at the entry side of the extension of the refrigerant pipe  180  extending between the fourth lithium ion battery cell  108  and the fifth lithium ion battery cell  110  as well as the first on/off valve  182  at the outlet side of the refrigerant pipe  180  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180 ; and drives the refrigerant pump  160  for the supersaturated liquid refrigerant to be moved along the circulation cycle of the refrigerant pipe  180  (S 16 ). 
         [0070]    Further, when it is determined in S 15  that the average temperature value is not the temperature value corresponding to the intermediate mode, the controller  200  determines that the average temperature value is a temperature value corresponding to the lowest mode, and opens all of the first to seventh valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  while driving the refrigerant pump  160  for the supersaturated liquid refrigerant to be moved along the circulation cycle of the refrigerant pipe  180  (S 17 ). 
         [0071]    After S 14 , S 16 , or S 17 , the controller  200  allows the electric shock applying unit  220  to apply an electric shock voltage for generating static electricity to the refrigerant pipe  180 , whereby heat generated by phase transformation of the supersaturated liquid refrigerant filled in the refrigerant pipe  180  from a liquid phase to a solid phase is transmitted to an inside of the lithium ion battery pack  100 , thereby preheating the battery pack (S 18 ). 
         [0072]    On the other hand, when it is determined in S 12  that the average temperature value is neither less than or equal to the predetermined cold season-mode temperature, the controller  200  determines whether the average temperature value is higher than or equal to the predetermined cooling-mode temperature (S 19 ). 
         [0073]    As a result, when it is determined that the average temperature value is higher than or equal to the predefined cooling-mode temperature, the controller  200  determines whether the average temperature value is a temperature value corresponding to the basic mode (S 20 ). 
         [0074]    As a result, when it is determined that the average temperature value is the temperature value corresponding to the basic mode, as shown in  FIG. 3   a , the controller  200  opens only the first on/off valve  182  at the outlet side of the refrigerant pipe  180  connected to the refrigerant pump  160  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  connected to the refrigerant reservoir  170  such that a refrigerant circulation cycle is established only by an inner peripheral region of the lithium ion battery pack  100  (S 21 ); and continuously drives the refrigerant pump  160  for the supersaturated liquid refrigerant to be circulated along the circulation cycle of the refrigerant pipe  180  to cool the lithium ion battery pack  100  (S 22 ). 
         [0075]    On the other hand, when it is determined in S 20  that the average temperature value is not the temperature value corresponding to the basic mode, the controller  200  determines whether the average temperature value is a temperature value corresponding to the intermediate mode (S 23 ). 
         [0076]    As a result, when it is determined that the average temperature value is the temperature value corresponding to the intermediate mode, as shown in  FIG. 3   b , the controller  200  opens the fourth on/off valve  188  at the entry side of the extension of the refrigerant pipe  180  extending between the second lithium ion battery cell  104  and the third lithium ion battery cell  106  and the sixth on/off valve  192  at the entry side of the extension of the refrigerant pipe  180  extending between the fourth lithium ion battery cell  108  and the fifth lithium ion battery cell  110  as well as the first on/off valve  182  at the outlet side of the refrigerant pipe  180  and the second on/off valve  184  at the inlet side of the refrigerant pipe  180  (S 24 ); and the operation proceeds to S 22 , whereby the controller  200  continuously drives the refrigerant pump  160  for the supersaturated liquid refrigerant to be circulated along the circulation cycle of the refrigerant pipe  180  to cool the lithium ion battery pack  100 . 
         [0077]    Further, when it is determined in S 23  that the average temperature value is not the temperature value corresponding to the intermediate mode, the controller  200  determines that the average temperature value is a temperature value corresponding to the highest mode and opens all of the first to seventh valves  182 ,  184 ,  186 ,  188 ,  190 ,  192 ,  194  (S 25 ). Thereafter, the operation proceeds to S 22  whereby the controller  200  continuously drives the refrigerant pump  160  for the supersaturated liquid refrigerant to be circulated along the circulation cycle of the refrigerant pipe  180  to cool the lithium ion battery pack  100 . 
         [0078]    Next, after S 18  or S 22 , the controller  200  determines whether use of the lithium ion battery pack  100  is terminated (S 26 ). 
         [0079]    As a result, when use of the lithium ion battery pack  100  is determined to be terminated, the controller cancels the mode for preheating or cooling the lithium ion battery  100  and finishes use of the battery (S 27 ). 
         [0080]    On the other hand, when it is determined in S 26  that use of the lithium ion battery pack  100  is not terminated, the operation returns to S 11 . 
         [0081]    Although some embodiments have been described herein, it should be understood that these embodiments are provided for illustration only and are not to be construed in any way as limiting the present invention, and that various modifications, changes, alterations, and equivalent embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. The scope of the present invention should be defined by the appended claims and equivalents thereof.