Title of Invention: Battery cell thermal conductivity measuring device and battery cell thermal conductivity measuring method using same
technical field
[One]
The present invention relates to an apparatus for measuring thermal properties of a pouch-type battery cell, specifically, thermal conductivity of the battery cell, and a method for measuring thermal conductivity using the same.
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0072383 on June 18, 2019, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
background
[3]
As the energy price of fossil fuels rises and interest in environmental pollution is growing, the demand for eco-friendly alternative energy sources is becoming an indispensable factor for future life. Accordingly, the demand for secondary batteries as an energy source is rapidly increasing.
[4]
Representatively, in terms of battery shape, there is a high demand for prismatic secondary batteries and pouch-type secondary batteries that can be applied to products such as mobile phones with thin thickness, and in terms of materials, lithium ion batteries with high energy density, discharge voltage, and output stability, Demand for lithium secondary batteries such as lithium ion polymer batteries is high.
[5]
[6]
Recently, a pouch-type battery having a structure in which a stack-type or stack/folding-type electrode assembly is embedded in a pouch-type battery case of an aluminum laminate sheet has attracted a lot of attention for reasons such as low manufacturing cost, low weight, and easy shape deformation. is also gradually increasing.
[7]
[8]
The pouch-type battery cell accommodates a stack-type or stack-folding-type electrode assembly manufactured by laminating a positive electrode, a separator, and a negative electrode. Each of the positive and negative electrodes is electrically connected by electrode tabs, and an electrode lead drawn out to the outside is connected to the electrode tabs.
[9]
The electrode assembly to which the electrode tab and the electrode lead are connected is accommodated in a pouch-type battery case, and then the electrolyte is injected. A pouch-type battery cell is manufactured by sealing the battery case while a part of the electrode lead is exposed to the outside.
[10]
[11]
On the other hand, the battery case of the pouch-type battery cell is made in the form of a pouch so that it is easy to process, there are few restrictions depending on the size or shape of the electrode assembly, and the space inside the battery cell can be used efficiently. Accordingly, the pouch-type battery cell has high energy density and can be processed into various shapes, and has recently been used in various types of mobile devices and automobile batteries. However, since the pouch-type battery cell is applied with a high energy density ranging from small devices to large devices, it may cause a temperature increase inside the device. Since this temperature rise affects the performance of the device itself or causes risks such as fire and explosion, it is important to understand the flow of heat emitted from the battery cell, that is, the thermal conductivity of the battery cell.
[12]
[13]
Thermal conductivity refers to a numerical value indicating the degree of heat conduction through an object, and is the value obtained by dividing the amount of heat flowing in a unit time through a unit area perpendicular to the flow of heat by the difference in temperature per unit length. Therefore, the higher the thermal conductivity, the better the heat passes, and in general, the metal has a high thermal conductivity.
[14]
As such a thermal conductivity measurement method, a hot wire method, a guarded heat flow method, and a guarded hot plate method are known. Among them, the guarded hot plate method is a method of measuring the thermal conductivity of a solid sample. It measures the amount of heat flowing from the high temperature side to the low temperature side while accurately measuring the temperature on both sides of the sample. This is the principle of measuring thermal conductivity. That is, an auxiliary hot plate called a guard plate is arranged around the hot plate so that heat flow can be accurately one-dimensionally formed in the sample, so that the hot plate has a constant temperature. In addition, accurate thermal conductivity can be calculated only when heat moves in a direction perpendicular to the surface of the plate.
[15]
Accordingly, the hot plate and the protective hot plate are arranged to be spaced apart from each other by a certain distance, and a space between them is sometimes filled with a material having low thermal conductivity.
[16]
Various structures have been studied for the protection hot plate method as well. In addition to the conventional method of calculating and measuring heat flow with one hot plate and one cooling plate, a test piece is placed between them. The so-called two-section method is also used.
[17]
However, in the case of the conventional protective hot plate method, it is designed only for measurement of a simple type test piece made of a single material. In the case of the two-sheet method, there is a difference in that the heat flow in the upward and downward directions is measured using two specimens, except that the accuracy is improved by averaging the thermal conductivity in the upward and downward directions. It is the same as the conventional method, and basically there is no difference from the conventional method in that a single material having unidirectional thermal conductivity is targeted.
[18]
However, in the case of a pouch-type battery cell, unlike a single material test piece, it contains various materials with different physical properties, such as positive and negative current collectors, separators, electrode mixtures, and battery cases, and the arrangement of each material is not uniformly dispersed. As a result, it appears different from the specimen of a single material.
[19]
Therefore, since it is difficult to evaluate the thermal characteristics of a battery cell with the conventional device and method for the protection hot plate method, a new device and method are needed to measure the same.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[20]
The present invention provides an apparatus and a measurement method using the same for independently measuring the thermal conductivity of a battery cell exhibiting anisotropy in each direction by improving the conventional thermal conductivity measuring apparatus and measuring method, which is difficult to measure the thermal characteristics of a battery cell aim to do
means of solving the problem
[21]
In order to achieve the above object, an apparatus for measuring thermal conductivity of a battery cell according to the present invention includes a hot plate including a heating element; It may include; a protective hot plate surrounding the hot plate in a spaced state from the side of the hot plate,
[22]
In addition, a measuring plate, a cooling plate, and a cooling unit may be sequentially included in the upper and lower portions in a direction perpendicular to the hot plate, respectively, and the measuring plate, the cooling plate, and the cooling unit are respectively disposed in the upper and lower directions of the hot plate has a symmetrical structure around the hot plate.
[23]
In this case, one battery cell may be disposed between the upper and lower measuring plates and the cooling plate to measure thermal conductivity.
[24]
[25]
On the other hand, the protection hot plate is to one-dimensionally guide the heat transfer direction of the hot plate vertically in a vertical direction with respect to the hot plate, and is the same as or higher than the hot plate so that the heat generated from the hot plate does not move laterally. It is characterized in that the temperature is maintained.
[26]
[27]
The thickness of the measuring plate is characterized in that it increases in proportion to the amount of heat generated from the hot plate. The measuring plate may have a thermal tendency toward a high-temperature surface close to the hot plate and a low-temperature surface closer to the cooling plate. However, as the thickness increases, the heat loss also increases, so it is necessary to adjust the thickness to an appropriate thickness according to the amount of heat.
[28]
[29]
It is preferable to use a metal material having excellent thermal conductivity and a well-known reference value for the measurement plate. Specifically, the measuring plate is preferably a metal or a metal alloy having a thermal conductivity of 50 W/m·K or more, and more specifically, it is characterized in that it is made of a metal material such as aluminum, copper, or an alloy thereof.
[30]
[31]
In addition, according to another embodiment of the present invention, a protective measuring plate surrounding the measuring plate at a position spaced apart from the measuring plate may be further included on the side surface of the measuring plate, and in this case, heat loss in the measuring plate can be further reduced.
[32]
[33]
Meanwhile, in order to further reduce heat lost to the side of the thermal conductivity measuring device, a heat insulating member made of a heat insulating material may be provided on the side of the battery cell thermal conductivity measuring device. The heat insulating member is preferably provided spaced apart from the thermal conductivity measuring device so that direct heat transfer is not made therethrough.
[34]
[35]
The hot plate may have a cylindrical or rectangular parallelepiped shape. The shape of the hot plate is not limited, but may be a rectangular shape or a square shape, most preferably a circular shape, in order to suppress heat loss in the lateral direction and to promote one-dimensional heat transfer in the vertical direction.
[36]
[37]
If the battery cell thermal conductivity measuring apparatus of the present invention is used, the thermal conductivity of a battery cell exhibiting different thermal characteristics in the upper and lower directions of the battery cell can be measured separately. Specifically, it is possible to separately measure the upper and lower directions in the vertical direction through the following steps.
[38]
calculating the amount of heat applied to the battery cells in an upper direction perpendicular to the hot plate;
[39]
calculating the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate;
[40]
Calculating the thermal conductivity of the battery cell using the amount of heat applied in the upper direction and the amount of heat applied in the lower direction.
[41]
[42]
In this case, the amount of heat applied to the battery cell in an upper direction perpendicular to the hot plate may be calculated by Equation 1 below.
[43]
[Equation 1]
[44]

[45]
(In Equation 1, P up is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, and T 2 is the battery of the measuring plate disposed on the hot plate. The temperature of the other surface facing the cell, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate, i is the hot plate The current applied to, V means the voltage applied to the hot plate.)
[46]
[47]
In addition, the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate may be calculated by Equation 2 below.
[48]
[Equation 2]
[49]

[50]
(In Equation 2, P down is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, and T 2 is the battery of the measuring plate disposed on the hot plate. The temperature of the other surface facing the cell, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate, i is the hot plate The current applied to, V means the voltage applied to the hot plate.)
[51]
[52]
Using the value of the amount of heat applied in the upward direction, the thermal conductivity in the upward direction of the battery cell may be calculated by Equation 3 below.
[53]
[Equation 3]
[54]

[55]
(In Equation 3, k up is the thermal conductivity in the vertical direction from the lower surface to the upper surface of the battery cell, P up is the amount of heat applied to the battery cell in the upper direction, L top is the thickness of the cooling plate, and A is a unit for measuring the amount of heat Area, T H is the temperature of the lower surface of the battery cell close to the hot plate of the battery cell, and T C is the temperature of the upper surface of the battery cell close to the cooling plate)
[56]
[57]
Meanwhile, by using the value of the amount of heat applied in the downward direction, the thermal conductivity in the downward direction of the battery cell may be calculated by Equation 4 below.
[58]
[Equation 4]
[59]

[60]
(In Equation 4, k down is the thermal conductivity in the vertical direction from the upper surface to the lower surface of the battery cell, P down is the amount of heat applied to the battery cell in the downward direction, L bottom is the thickness of the cooling plate, and A is a unit for measuring the amount of heat Area, T' H is the temperature of the upper surface of the battery cell close to the hot plate of the battery cell, and T' C is the temperature of the lower surface of the battery cell close to the cooling plate)
Effects of the Invention
[61]
The present invention relates to an apparatus for measuring thermal conductivity of a battery cell and a method for measuring thermal conductivity using the same, and it is possible to measure the thermal conductivity of a pouch-type battery cell exhibiting anisotropic thermal conductivity by separating it along each direction, and through this, a rechargeable battery battery Stability evaluation according to thermal characteristics of products using cells can be efficiently performed.
Brief description of the drawing
[62]
1 schematically shows a structure viewed from the side of a conventional thermal conductivity measuring device.
[63]
Figure 2 schematically shows the structure seen from the side of another conventional thermal conductivity measuring device.
[64]
Figure 3 shows the structure seen from the side of the thermal conductivity measuring apparatus according to an embodiment of the present invention.
[65]
4 is a three-dimensional view of the structure of a thermal conductivity measuring device according to an embodiment of the present invention.
[66]
5 is a view showing the structure seen from the side of the thermal conductivity measuring apparatus according to another embodiment of the present invention.
[67]
6 is a three-dimensional view of the structure of a thermal conductivity measuring device according to another embodiment of the present invention.
Modes for carrying out the invention
[68]
Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.
[69]
[70]
In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention. Terms used to describe various components are for helping understanding, and the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.
[71]
[72]
As used throughout the specification of the present invention, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one It should be understood that it does not preclude the possibility of the presence or addition of or more other features or numbers, steps, operations, components, parts, or combinations thereof.
[73]
[74]
Also, when a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where it is "on" another part, but also the case where there is another part in between. Conversely, when a part of a layer, film, region, plate, etc. is said to be “under” another part, it includes not only cases where it is “directly under” another part, but also cases where another part is in between. In addition, in the specification of the present invention, "on" may include the case of being disposed not only on the upper part but also on the lower part.
[75]
[76]
Throughout this specification, "upper", "lower", "upward", "downward", "upper surface", and "lower surface" are all relative positions in the vertical direction with respect to the hot plate of the thermal conductivity measuring device of the present invention. means For example, "upward" means heat transfer in a vertical direction with respect to the hot plate, and "top" of a battery cell means that a pouch-type battery cell is horizontally placed in a thermal conductivity measuring device. When done, it means one side facing the "upward". Therefore, the "lower surface" of the battery cell means the other surface opposite to the "upper surface".
[77]
[78]
Hereinafter, the present invention will be described in more detail.
[79]
[80]
Recently, a variety of product groups, from mobile devices to electric vehicles, require high-energy, high-integration secondary batteries. The pouch-type secondary battery has excellent space utilization and is suitable for manufacturing secondary batteries with high energy density. However, the amount of heat generated during use increases in proportion to such directness. If high heat is not efficiently discharged when high heat is generated in the secondary battery, a thermal runaway phenomenon may occur in the secondary battery itself, which may adversely affect depending on the thermal characteristics of the electronic device including the secondary battery. Therefore, it is very important to measure the thermal characteristics of the pouch-type battery cell.
[81]
However, in the case of a battery cell, unlike a material made of a single material, heat conduction occurs anisotropically, so it is difficult to grasp the characteristics with a conventional thermal conductivity measuring device. In order to solve this problem, the thermal conductivity measuring device of the present invention can separate and measure the vertical thermal conductivity from the lower surface to the upper surface and the vertical thermal conductivity from the upper surface to the lower surface of the pouch-type battery cell. do.
[82]
Through this, it is possible to accurately determine at what ratio the heat generated inside the battery cell is transferred to the upper and lower surfaces of the battery cell, and it is designed by optimizing the arrangement position and direction of the secondary battery in consideration of the thermal characteristics of internal parts of electronic products. it is possible to do
[83]
[84]
Thermal conductivity measuring apparatus of the present invention includes a hot plate including a heating element; It may include; a protective hot plate surrounding the hot plate in a spaced state from the side of the hot plate,
[85]
In addition, a measuring plate, a cooling plate, and a cooling unit may be sequentially included in the upper and lower portions in a direction perpendicular to the hot plate, respectively, and the measuring plate, the cooling plate, and the cooling unit are respectively disposed in the upper and lower directions of the hot plate has a symmetrical structure around the hot plate. Due to this structure, the heat generated from the hot plate moves from the hot plate to the upper and lower cooling plates in a direction perpendicular to the direction.
[86]
In this case, one battery cell may be disposed between the upper and lower measuring plates and the cooling plate to measure thermal conductivity.
[87]
[88]
On the other hand, the protection hot plate is to one-dimensionally guide the heat transfer direction of the hot plate vertically in a vertical direction with respect to the hot plate, and is the same as or higher than the hot plate so that the heat generated from the hot plate does not move laterally. It is characterized in that the temperature is maintained. If the protective hot plate falls to a lower temperature than the hot plate, heat transfer occurs laterally due to the characteristic of moving from a high temperature to a low temperature, so it is difficult to accurately measure the thermal conductivity.
[89]
[90]
The thickness of the measuring plate is characterized in that it increases in proportion to the amount of heat generated from the hot plate. The measuring plate may have a thermal tendency toward a high-temperature surface close to the hot plate and a low-temperature surface closer to the cooling plate. That is, the thicker the thickness of the measurement plate, the more precisely the measurement of thermal properties is possible. However, since heat loss increases as the thickness increases, it is necessary to adjust the thickness to an appropriate thickness according to the amount of heat generated from the hot plate.
[91]
[92]
It is preferable to use a metal material having excellent thermal conductivity and a well-known reference value for the measurement plate. Specifically, as a material for the measurement plate, aluminum, copper, or an alloy thereof may be selected and used. If the thermal conductivity is low, the heat loss increases accordingly, making it difficult to accurately measure the amount of heat.
[93]
On the other hand, the measuring plate is a component that serves as a standard for measuring thermal conductivity, and when calculating thermal conductivity, the temperature of one surface close to the hot plate and the other surface close to the cooling plate are respectively measured.
[94]
[95]
In addition, in order to minimize heat loss due to an increase in the thickness of the measuring plate, the measuring plate may be designed in a structure similar to that of the hot plate. According to another embodiment of the present invention, a protective measuring plate surrounding the measuring plate at a position spaced apart from the measuring plate may be further included on the side surface of the measuring plate, and in this case, heat loss in the measuring plate is further reduced can be reduced
[96]
[97]
In order to further reduce heat lost to the side of the thermal conductivity measuring device, a heat insulating member made of a heat insulating material may be provided on the side of the battery cell thermal conductivity measuring device. The heat insulating member is preferably provided spaced apart from the thermal conductivity measuring device so that direct heat transfer is not made therethrough.
[98]
[99]
The hot plate may have a cylindrical or rectangular parallelepiped shape. The shape of the hot plate is not limited, but may be a rectangular shape or a square shape, most preferably a circular shape, in order to suppress heat loss in the lateral direction and to promote one-dimensional heat transfer in the vertical direction.
[100]
[101]
If the battery cell thermal conductivity measuring apparatus of the present invention is used, the thermal conductivity of a battery cell exhibiting different thermal characteristics in the upper and lower directions of the battery cell can be measured separately. Specifically, it is possible to separately measure the upper and lower directions in the vertical direction through the following steps.
[102]
calculating the amount of heat applied to the battery cells in an upper direction perpendicular to the hot plate;
[103]
calculating the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate;
[104]
Calculating the thermal conductivity of the battery cell using the amount of heat applied in the upper direction and the amount of heat applied in the lower direction.
[105]
[106]
Among the conventional protective hot plate methods, the two-sheet method is a principle of forming a constant heat flux in the vertical direction of the main hot plate in a state where the temperatures of the main and auxiliary hot plates are the same. Accordingly, the size of the auxiliary hot plate must be very large, and the auxiliary hot plate must be maintained at the exact same temperature as the hot plate. Also, assuming that the upper and lower test pieces have the same material conductivity, the amount of heat is calculated as the average of the conductivities in the upward and downward directions. Therefore, although it is suitable for measuring the thermal properties of an isotropic material or an insulator with uniform thermal conductivity, it is impossible to measure the thermal conductivity of a pouch-type battery cell in this way.
[107]
[108]
Therefore, the thermal conductivity measuring apparatus of the present invention separates and separately measures the amount of heat in the upward direction and the amount of heat in the downward direction by arranging the measuring plates above and below the hot plate. In addition, the heat plate must be made large to correspond to the size of the battery cell, but the protective hot plate can be made relatively small according to the arrangement of the measuring plate, and the temperature of the protective hot plate can be maintained at a higher level than the hot plate, so it is easy to control. .
[109]
[110]
The measuring principle of this thermal conductivity measuring device is as follows.
[111]
The total amount of heat generated from the hot plate can be expressed as the product of current and voltage, which is equal to the sum of the amount of heat in the upward direction and the amount of heat in the downward direction.
[112]
On the other hand, by using the surface temperatures of the upper and lower measuring plates, the ratio of the amount of heat applied in the vertical direction can be obtained. Using this, the thermal conductivity in the upward and downward directions of the battery cell can be obtained, respectively, and the ratio can also be easily calculated.
[113]
[114]
First, the amount of heat applied to the battery cell in an upper direction perpendicular to the hot plate may be calculated by Equation 1 below.
[115]
[Equation 1]
[116]

[117]
(In Equation 1, P up is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, and T 2 is the battery of the measuring plate disposed on the hot plate. The temperature of the other surface facing the cell, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate, i is the hot plate The current applied to, V means the voltage applied to the hot plate.)
[118]
[119]
Next, the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate may be calculated by Equation 2 below.
[120]
[Equation 2]
[121]

[122]
(In Equation 2, P down is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, and T 2 is the battery of the measuring plate disposed on the hot plate. The temperature of the other surface facing the cell, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate, i is the hot plate The current applied to, V means the voltage applied to the hot plate.)
[123]
[124]
The thermal conductivity of the battery cell may be calculated using the respective calculated calorie values. The thermal conductivity calculation factors according to the following Equations 3 and 4 are shown below.
[125]
[126]
First, by using the value of the amount of heat applied in the upward direction, the thermal conductivity in the upward direction of the battery cell may be calculated by Equation 3 below.
[127]
[Equation 3]
[128]

[129]
(In Equation 3, k up is the thermal conductivity in the vertical direction from the lower surface to the upper surface of the battery cell, P up is the amount of heat applied to the battery cell in the upper direction, L top is the thickness of the cooling plate, and A is a unit for measuring the amount of heat Area, T H is the temperature of the lower surface of the battery cell close to the hot plate of the battery cell, and T C is the temperature of the upper surface of the battery cell close to the cooling plate)
[130]
[131]
Using the value of the amount of heat applied in the downward direction, the thermal conductivity in the downward direction of the battery cell may be calculated by Equation 3 below.
[132]
[Equation 4]
[133]

[134]
[135]
(In Equation 4, k down is the thermal conductivity in the vertical direction from the upper surface to the lower surface of the battery cell, P down is the amount of heat applied to the battery cell in the downward direction, L bottom is the thickness of the cooling plate, and A is a unit for measuring the amount of heat Area, T' H is the temperature of the upper surface of the battery cell close to the hot plate of the battery cell, and T' C is the temperature of the lower surface of the battery cell close to the cooling plate)
[136]
[137]
With the k up and k down values, the thermal conductivity of the battery cell exhibiting anisotropy can be calculated separately for each direction, and the rate at which heat is transferred in each direction can be easily found.
[138]
[139]
Hereinafter, the structure of the thermal conductivity measuring device of the present invention will be described in more detail with reference to each drawing.
[140]
[141]
1 is a conventional thermal conductivity measuring device 10, including a hot plate 11, a protective hot plate 12, a measuring plate 13, a protective plate 14, a cooling plate 16, a heat insulating material 17, and a protective plate 18 ), and the test piece 15 is placed on the cooling plate 16 . Since the heat generated from the hot plate 11 moves vertically in the direction of the cooling plate 16 , heat transfer from the upper part to the lower part of the test piece 15 occurs. Therefore, this method is applicable only to isotropic materials. In addition, since the heat loss to the side is large, it is possible to grasp the approximate thermal characteristics, but precise measurement is impossible. In addition, the measuring plate 13 does not directly measure the amount of heat generated by the hot plate 11 , but serves as an insulator to prevent heat loss in measuring the amount of heat. Accordingly, the measuring device 10 of FIG. 1 does not measure the vertical surface temperature of the measuring plate 13 . On the other hand, the measuring plate provided in the measuring device of the present invention, unlike the conventional measuring device, exists in a vertically symmetrical structure and moves in the vertical direction of the hot plate by directly measuring the surface temperature of the measuring plate instead of acting as an insulator. It is used to calculate the amount of heat.
[142]
[143]
FIG. 2 is another conventional thermal conductivity measuring device 20, which is a further improvement of the thermal conductivity measuring device 10 of FIG. 1 . It includes a hot plate 21, a measuring plate 22, a measuring instrument 23, a guard plate 24, a protection heat plate 25, a cooling plate 27, a cooling unit 28 and a heat insulating material 29, and a test piece 26 is disposed on the cold plate 27, and heat transfer occurs in the upward to downward direction. Although the heat loss is further suppressed in the thermal conductivity measuring device 10 of FIG. 1 , it is not suitable for measuring the thermal conductivity of the battery cell because it is possible to measure only the thermal conductivity in one direction.
[144]
[145]
3 and 4 are one embodiment of the thermal conductivity measuring apparatus 100 of the present invention. The heat moves vertically upwards and downwards from the central heating plate 110 , and the protective heating plate 120 is spaced apart from each other on the side surface of the heating plate 110 to prevent loss in the lateral direction. In addition, an upper measuring plate 131 and a lower measuring plate 132 exist adjacent to the hot plate in the vertical direction, and by measuring the temperature of each surface of the upper measuring plate 131 and the lower measuring plate 132, in the vertical direction The rate of heat transferred is known. Next, the upper cooling plate 141 and the lower cooling plate 142 are disposed, and the upper cooling unit 151 and the lower cooling unit 152 are disposed adjacent thereto to maintain a low temperature of the cooling plate. The battery cells are respectively arranged in the upper and lower directions (101, 102), and in order to separate and calculate the thermal conductivity from the lower surface to the upper surface and the thermal conductivity from the upper surface to the lower surface, the same type of battery cells are run in the same direction. should be placed
[146]
[147]
5 and 6 are another embodiment of the thermal conductivity measuring apparatus 200 of the present invention. The heat is vertically moved upward and downward from the central heating plate 210 , and the protective heating plate 220 is spaced apart from each other on the side surface of the heating plate 210 to prevent lateral loss. In addition, an upper measuring plate 131 and a lower measuring plate 132 exist adjacent to the hot plate in the vertical direction, and by measuring the temperature of each surface of the upper measuring plate 131 and the lower measuring plate 132, in the vertical direction The rate of heat transferred is known. In addition, on the side of the upper measuring plate 131 and the lower measuring plate 132, respectively, the protection measuring plates 241 and 242 are disposed to be spaced apart. Through this, it is possible to further reduce heat loss in the measurement plate, while maintaining uniform heat transfer characteristics. Next, the upper cooling plate 251 and the lower cooling plate 252 are arranged, and the upper cooling unit 261 and the lower cooling unit 262 are arranged adjacent thereto to maintain a low temperature of the cooling plate. The battery cells are respectively arranged in the upper and lower directions (201, 202), and in order to separate and calculate the thermal conductivity from the lower surface to the upper surface and the thermal conductivity from the upper surface to the lower surface, the same type of battery cells are placed in the same direction. should be placed
[148]

[149]
10: thermal conductivity measuring device
[150]
11: sole plate
[151]
12: protection heat plate
[152]
13: measuring plate
[153]
14: protection plate
[154]
15: test piece
[155]
16: cold plate
[156]
17: insulation
[157]
18: protection plate
[158]
20: thermal conductivity measuring device
[159]
21 : sole plate
[160]
22: measuring plate
[161]
23: measuring instrument
[162]
24: protection plate
[163]
25: protection heat plate
[164]
26: test piece
[165]
27: cold plate
[166]
28: cooling unit
[167]
29: insulation
[168]
100: thermal conductivity measuring device
[169]
101: upper battery cell
[170]
102: lower battery cell
[171]
110: hot plate
[172]
120: protection heat plate
[173]
131: upper measuring plate
[174]
132: lower measuring plate
[175]
141: upper cooling plate
[176]
142: lower cooling plate
[177]
151: upper cooling unit
[178]
152: lower cooling unit
[179]
150: insulation material
[180]
200: thermal conductivity measuring device
[181]
201: upper battery cell
[182]
202: lower battery cell
[183]
210: hot plate
[184]
220: protection heat plate
[185]
231: upper measuring plate
[186]
232: lower measuring plate
[187]
241: upper protection measurement plate
[188]
242: lower protection measuring plate
[189]
251: upper cooling plate
[190]
252: lower cooling plate
[191]
261: upper cooling unit
[192]
262: lower cooling unit
[193]
270: insulation
Claims
[Claim 1]
a hot plate including a heating element; and a protective hot plate surrounding the hot plate while being spaced apart from the side of the hot plate, and sequentially including a measuring plate, a cooling plate, and a cooling unit at the upper and lower portions in a direction perpendicular to the hot plate, respectively, to form a symmetrical structure and a battery cell thermal conductivity measuring device, characterized in that each battery cell is disposed between the upper and lower measuring plates and the cooling plate.
[Claim 2]
According to claim 1, wherein the protective heat plate is a battery cell thermal conductivity measuring device, characterized in that maintained at the same or higher temperature than the hot plate.
[Claim 3]
The battery cell thermal conductivity measuring device according to claim 1, wherein the thickness of the measuring plate increases in proportion to the amount of heat generated from the hot plate.
[Claim 4]
The battery cell thermal conductivity measuring device according to claim 1, wherein the measuring plate is made of aluminum, copper, or an alloy thereof.
[Claim 5]
The battery cell thermal conductivity measuring device according to claim 1, further comprising a protective measuring plate surrounding the measuring plate at a position spaced apart from the measuring plate on a side surface of the measuring plate.
[Claim 6]
According to claim 1, wherein the hot plate is a battery cell thermal conductivity measuring device, characterized in that the cylindrical or rectangular parallelepiped shape.
[Claim 7]
The thermal conductivity measuring device according to claim 1, wherein an insulating member made of an insulating material is provided on a side surface of the battery cell thermal conductivity measuring device to be spaced apart from the thermal conductivity measuring device.
[Claim 8]
A method of measuring the thermal conductivity of a battery cell using the battery cell thermal conductivity measuring apparatus of claim 1, the method comprising: calculating an amount of heat applied to the battery cell in an upper direction perpendicular to a hot plate; calculating the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate; Calculating the thermal conductivity of the battery cell by using the amount of heat applied in the upward direction and the amount of heat applied in the downward direction;
[Claim 9]
The method of claim 8, wherein the amount of heat applied to the battery cell in an upward direction perpendicular to the hot plate is calculated by Equation 1 below. [Equation 1] (In Equation 1, P up is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, T 2 is disposed on the hot plate temperature of the other surface facing the battery cell of the measuring plate, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate Temperature, i is the current applied to the hot plate, and V is the voltage applied to the hot plate.)
[Claim 10]
The method of claim 8, wherein the amount of heat applied to the battery cells in a downward direction perpendicular to the hot plate is calculated by Equation 2 below. [Equation 2] (In Equation 2, P down is the amount of heat applied to the battery cell in the downward direction, T 1 is the temperature of one surface facing the hot plate of the measuring plate disposed on the hot plate, T 2 is disposed on the hot plate temperature of the other surface facing the battery cell of the measuring plate, T 3 is the temperature of one surface facing the hot plate of the measuring plate disposed under the hot plate, T 4 is the temperature of the one surface facing the battery cell of the measuring plate disposed under the hot plate Temperature, i is the current applied to the hot plate, and V is the voltage applied to the hot plate.)
[Claim 11]
The method of claim 8, wherein the thermal conductivity in the upward direction of the battery cell is calculated by Equation 3 below. [Equation 3] (in Equation 3, k up is the thermal conductivity in the vertical direction from the lower surface to the upper surface of the battery cell, P up is the amount of heat applied to the battery cell in the upper direction, L top is the thickness of the cooling plate, and A is The unit area for measuring the amount of heat, T H is the temperature of the lower surface of the battery cell close to the hot plate of the battery cell, and T C is the temperature of the upper surface of the battery cell close to the cooling plate)
[Claim 12]
The method according to claim 8, wherein the thermal conductivity in the downward direction of the battery cell is calculated by Equation 4 below. [Equation 4] (In Equation 4, k down is the vertical thermal conductivity from the top to the bottom of the battery cell, P down is the amount of heat applied to the battery cell in the downward direction, L bottom is the thickness of the cooling plate, A is The unit area for measuring the amount of heat, T' H is the temperature of the upper surface of the battery cell close to the battery cell hot plate, and T' C is the temperature of the lower surface of the battery cell close to the cooling plate)