KR101676407B1 - Test method for thermal pad and method of fabricating battery module using the same - Google Patents

Abstract

A method of inspecting a state of adhesion between a thermal pad and a surface to be adhered, and a method of manufacturing a battery module including the method, wherein a thermal pad is completely bonded to a surface to be adhered, . A method of inspecting a thermal pad according to the present invention includes: a battery cell laminate in which battery cells are stacked; A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack; A cooling plate interposed between the cooling part and the battery cells; And a thermal pad provided on a thermal interface formed between the battery cell stack, the cooling unit, and the cooling plate, the method comprising: inspecting a contact state between the thermal pad and the object to be adhered, Disposing a thermal pad and a pressure-sensitive paper on the pad; Applying pressure to the thermal pad and the pressure sensitive paper; And inspecting the decompression paper.

Description

TECHNICAL FIELD [0001] The present invention relates to a thermal pad inspection method and a battery module manufacturing method using the same,

The present invention relates to a battery module manufacturing method, and more particularly, to a battery module manufacturing method that includes a battery module including an electrode assembly composed of a positive electrode plate, a separator, and a negative electrode plate, And a manufacturing method thereof. The present invention particularly relates to a method of manufacturing a battery module in which a thermal pad is interposed between a cooling member and battery cells.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. Also, the secondary battery is attracting attention as a power source for an electric vehicle (EV) and a hybrid electric vehicle (HEV), which are suggested as solutions for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels .

BACKGROUND ART A middle- or large-sized device such as an automobile uses a battery module in which a plurality of battery cells are electrically connected and a middle- or large-sized battery pack including the same as a unit module due to the necessity of a high output large capacity. Since the battery module and the battery pack are preferably manufactured with a small size and a weight, a prismatic battery, a pouch-shaped battery, or the like, which can be stacked at a high density and have a small weight to capacity ratio, are mainly used as unit cells of a battery module. Particularly, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has attracted much attention due to its advantages such as small weight, low manufacturing cost, and easy shape deformation.

The battery cells constituting the battery module generate a large amount of heat during the charging and discharging process. Particularly, a laminate sheet of a pouch-type battery widely used for a high-output large-capacity battery module and a battery pack is coated with a polymer material having a low thermal conductivity, so that it is difficult to effectively cool the entire battery cell. If the heat of the battery module generated during the charging and discharging process can not be effectively removed, heat accumulation may occur, thereby accelerating the deterioration of the battery module and possibly causing ignition or explosion. Therefore, a cooling member for cooling the battery cells built in the high-power, large-capacity battery module and the battery pack in which the battery module is mounted is necessarily required.

Generally, a battery module is manufactured by stacking a plurality of battery cells at a high density, and adjacent battery cells are stacked at a predetermined interval so as to remove heat generated during charging and discharging. For example, the battery cells themselves may be sequentially stacked while being spaced apart from each other by a predetermined space, or in the case of a battery cell having low mechanical rigidity, one or a combination of two or more batteries may be built in a cartridge or the like. The battery module can be configured.

A heat transfer member which is in thermal contact with the battery cells and a water cooling type or air cooling type cooling unit which removes heat absorbed by the heat transfer member are used so as to effectively remove the heat accumulated in the stacked battery cells. The heat transfer member is a heat bridge for connecting the battery cell and the cooling unit, and moves the heat of the battery cell to the cooling unit to lower the heat of the battery cell.

Meanwhile, a thermal pad is used to improve the thermal interface formed in the laminated structure of the cooling unit, the heat transfer member, and the battery cells. The thermal pad may be a sheet-like member having a predetermined thickness formed with bonding surfaces on both sides and interposed between the heat conductive member and the battery cell or between the heat conductive member and the cooling member.

For effective cooling, the thermal interface with the thermal pad must be fully contacted by the thermal pad. In order to bond the thermal pad, a thermal pad is spread on the surface to be adhered, usually a wide surface of the heat conductive member, and a predetermined pressure is applied to the thermal pad. However, if the surface to be adhered is not smooth or the pressure is not uniform, the thermal pad and the object to be adhered are not properly adhered to each other. If bubbles are formed, the thermal pad and the object to be adhered are spread, Of course, the physical fixing force of the battery cell with respect to the heat transfer member is weak, for example, the heat transfer member can be easily detached from the battery cell due to impact or vibration applied from the outside.

The degree of adhesion or degree of the thermal pad can be guessed visually, but there is no way to measure the bonding area. In addition, the adhesion problem is due to the unevenness of the pressure, which is not uniformly adjusted, or when the pressure is not set to an optimal value, so there is no way to evaluate the pressure uniformity, which is very important for process stabilization. In particular, as the size of the object to be adhered becomes larger, the influence of the adhering area also increases, so a method of inspecting the adhered state more closely is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method of inspecting a state of adhesion between a thermal pad and a surface to be adhered, And a method of manufacturing a battery module that can increase heat radiation and adhesion efficiency.

According to another aspect of the present invention, there is provided a method of inspecting a thermal pad comprising: a battery cell laminate having battery cells stacked thereon; A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack; A cooling plate interposed between the cooling part and the battery cells; And a thermal pad provided on a thermal interface formed between the battery cell stack, the cooling unit, and the cooling plate, the method comprising: inspecting a contact state between the thermal pad and the object to be adhered, Disposing a thermal pad and a pressure-sensitive paper on the pad; Applying pressure to the thermal pad and the pressure sensitive paper; And inspecting the decompression paper.

The pressure sensitive area may be a film including a film containing a coloring agent and a color developing agent. The adhesion area, adhesion pressure and pressure uniformity of the thermal pad can be measured through the area of the discolored portion of the pressure-sensitive paper, the degree of discoloration, and the distribution of the discolored portion.

The method of manufacturing a battery module according to the present invention uses the above-described method of inspecting a thermal pad, comprising: a battery cell laminate in which battery cells are stacked; A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack; A cooling plate interposed between the cooling part and the battery cells; And a thermal pad provided on a thermal interface formed between the battery cell stack, the cooling unit, and the cooling plate, the method comprising: inspecting a state of adhesion between the thermal pad and a surface to be adhered; And an optional step of feeding back the result of the step to the manufacturing method.

In the method of manufacturing a battery module according to the present invention, the inspecting step may include: disposing a thermal pad and a pressure sensitive adhesive on the surface to be adhered; Applying pressure to the thermal pad and the pressure sensitive paper; And inspecting the pressure sensitive adhesive sheet.

The manufacturing method may include a step of fastening the laminated structure including the battery cell laminate, the cooling part, the cooling plate, and the thermal pad. At this time, it is possible to perform the inspecting step by changing the fastening point of the fastening step or the pressure at the time of fastening.

The manufacturing method includes: placing the thermal pad on the contact surface and pressing the thermal pad using a pressing means; And assembling the laminated structure including the battery cell laminate, the cooling part, the cooling plate, and the thermal pad. At this time, it is possible to perform the inspecting step by changing the shape, position and applied pressure of the pressing means.

Wherein the battery module further includes cooling fins interposed at an interface of the battery cells and having ends protruding from one side or both sides of the battery cell stack body and the cooling unit is mounted on a protruding end portion of the cooling fins Lt; / RTI > At this time, the battery cell has a positive electrode and a negative electrode terminal protruded on one side of the outer circumferential surface, or a positive electrode terminal protruded on one side of the outer circumferential surface and a negative electrode terminal protruded on the opposite side, The end portion may protrude in a direction perpendicular to the direction in which the terminal protrudes. The cooling plate may be machined to form an air flow path.

In one preferred embodiment, the battery cell is a plate-shaped battery cell, and one side or both sides of the battery cell are stacked so as to face adjacent battery cells to form a battery cell stack body. Particularly, the plate-shaped battery cell is a pouch-shaped battery cell having a structure in which an outer peripheral surface of a battery case is thermally fused and sealed while an electrode assembly is embedded in a battery case of a laminate sheet including a resin layer and a metal layer, And the outer circumferential surface of the heat-sealed member may be fixed between the cartridges forming the battery cell stack by fixing the battery cells.

According to the present invention, the adhesion state of the thermal pad is measured and fed back to the battery module manufacturing method, whereby the pressure applied to the thermal pad can be made uniform, so that the bonding state can be made even. This pressure uniformity is important for stabilizing the process of the battery module manufacturing method.

According to the present invention, since the inspection of the bonding state of the thermal pad is performed so that the thermal interface with the thermal pad can be completely contacted by the thermal pad, heat transfer through the thermal pad is properly performed, It is possible to prevent the members from falling off from the battery module due to impact or vibration exerted from the outside.

As described above, according to the present invention, the thermal pad can be completely bonded to the surface to be adhered by checking the adhesion between the thermal pad and the surface to be adhered, and heat radiation and adhesion efficiency can be improved.

FIG. 1 is a schematic view of a battery module that can be manufactured by the method of manufacturing a battery module according to an embodiment of the present invention.
FIG. 2 and FIG. 3 are diagrams showing inspection steps in a method of manufacturing a battery module according to the present invention.
Figs. 4 and 5 show exemplary results when the roller is applied to the pressure sensitive paper according to the experimental example of the present invention.
6 is an exploded perspective view of a battery module that can be manufactured by the method of manufacturing a battery module according to another embodiment of the present invention.
FIG. 7 is a schematic cross-sectional view taken along a cross section across battery cells in the battery module shown in FIG. 6;
8 is a photograph showing an experimental example according to the present invention in which a pressure sensitive paper is applied to the manufacture of the battery module as shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know. It should be noted that the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention so that various equivalents And variations are possible.

FIG. 1 is a schematic view of a battery module that can be manufactured by the method of manufacturing a battery module according to an embodiment of the present invention.

Referring to FIG. 1, a battery module 100 that can be manufactured by the method of manufacturing a battery module according to an embodiment of the present invention includes a battery cell stack 30 in which battery cells 10 are stacked, a cooling unit 60, a cooling plate 70, and a thermal pad 80.

The cooling plate 70 moves the heat generated in the battery cell 10 to the outside of the battery cell 10 while being tightly fixed to the battery cell stack 30 with the thermal pad 80 interposed therebetween, The portion 60 receives heat from the cooling plate 70 and removes it. Although the thermal pad 80 is interposed between the battery cell stack 30 and the cooling plate 70 in the drawing, the thermal pad 80 is interposed between the cooling plate 70 and the cooling portion 60. However, . That is, the thermal pad 80 may be located at one or more of the thermal interface formed in the laminated structure of the cooling section 60, the cooling plate 70, and the battery cell laminate 30. In any case, the thermal pad 80 is adhered to the cooling plate 70, and thus the cooling plate 70 is always included in the surface to be bonded of the thermal pad 80.

The battery cell 10 is preferably a plate-shaped battery cell so as to provide a high deposition rate in a limited space. The battery cell 10 is stacked so that one surface or both surfaces of the battery cell 10 face the adjacent battery cells 10 to form a battery cell stack body 30 .

The battery cell 10 includes an electrode assembly composed of a positive electrode plate, a separator and a negative electrode plate. The positive electrode lead and the negative electrode lead are electrically connected to a plurality of positive electrode tabs and negative electrode tabs protruding from the positive electrode plate and the negative electrode plate of each battery cell 10, .

As the material of the positive electrode plate, aluminum is mainly used. Alternatively, the positive electrode plate may be formed by surface-treating a surface of stainless steel, nickel, titanium or aluminum or stainless steel with carbon, nickel, titanium, silver or the like. Further, if the secondary battery is made of a material having high conductivity without causing a chemical change, there is no limitation to use it as a positive electrode plate.

A positive electrode tab may be provided on a part of the positive electrode plate, and the positive electrode tab may be formed to extend the positive electrode plate. Alternatively, it is also possible to form a configuration in which a member made of a conductive material is joined to a predetermined portion of the positive electrode plate through welding or the like. Further, the positive electrode material may be applied and dried on a part of the outer surface of the positive electrode plate to form the positive electrode tab.

The negative electrode plate corresponding to the positive electrode plate is mainly made of a copper material. Alternatively, the cathode plate may be a surface treated with carbon, nickel, titanium or silver on the surface of stainless steel, aluminum, nickel, titanium, copper or stainless steel, and aluminum-cadmium alloy or the like may be used.

The negative electrode plate may also be provided with a negative electrode tab in a certain area and may be formed to extend from the negative electrode plate as in the positive electrode tab described above. In addition, the negative electrode plate may be formed by welding a conductive member to a predetermined portion of the negative electrode plate Or it may be formed in such a manner that a negative electrode material is applied and dried on a part of the outer circumferential surface of the negative electrode plate.

The positive electrode lead is electrically connected to the positive electrode tab provided on the positive electrode plate, and the negative electrode lead is electrically connected to the negative electrode tab provided on the negative electrode plate. Preferably, the positive electrode lead and the negative electrode lead are bonded to a plurality of positive electrode tabs and a plurality of negative electrode tabs, respectively.

The positive electrode plate and the negative electrode plate are respectively coated with a positive electrode active material and a negative electrode active material. LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ or Li _{1 + z} Ni _{1 -xy} Co _x M _y O ₂ (0? 1, 0? y? 1, 0? x + y? 1, 0? z? 1, and M is a metal such as Al, Sr, Mg, La, or Mn). The negative electrode active material is a carbonaceous active material, and examples of the negative electrode active material include a carbon material such as crystalline carbon, amorphous carbon, carbon composite, carbon fiber, lithium metal, lithium alloy and the like. The types and chemical compositions of the cathode active material and the anode active material may vary depending on the kind of the secondary battery. Therefore, it should be understood that the specific examples given above are only examples.

The separation membrane is not particularly limited as long as it has a porous material. The separation membrane may be a porous polymer membrane such as a porous polyolefin membrane, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene, polymethyl methacrylate, polyacrylonitrile, polyvinyl Polyvinyl pyrrolidone, polyvinyl acetate, ethylene vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinyl alcohol, cyanoethylcellulose, Polybutylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polyether ether ketone, polyether sulfone, polyether sulfone, polyether sulfone, , Poly Alkenylene may be formed of oxide, polyphenylene sulfide, polyethylene naphthalene, a non-woven film, a porous web (web) or a mixture film having a structure like. An inorganic particle may be adhered to an end surface or both surfaces of the separation membrane.

The inorganic particles are preferably inorganic particles having a high dielectric constant of 5 or more, more preferably inorganic particles having a dielectric constant of 10 or more and a low density. This is because it can easily transfer lithium ions moving in the cell. Non-limiting examples of inorganic particles having a high dielectric constant of 5 or more is _{Pb (Zr, Ti) O 3} (PZT), Pb 1 - x La x Zr 1 -y Ti y O 3 (PLZT), Pb (Mg 3 Nb _{2/3) O 3 -PbTiO 3} (PMN-PT), BaTiO 3, HfO 2, SrTiO 3, TiO 2, Al 2 O 3, ZrO 2, SnO 2, CeO 2, MgO, CaO, ZnO, Y 2 O ₃ Or a mixture thereof.

The battery cell stack 30 may have a structure in which a plurality of battery cells 10 are simply stacked with an insulating film interposed between the battery cells 10. Alternatively, the battery cell stack 30 may be formed by arranging the battery cells 10 at appropriate intervals on the top and / or bottom of the insulating film, then folding the insulating film together with the battery cell 10 in one direction, And the battery cell 10 is inserted between the stacked structure. As another example, the battery cell stack 30 may be a pouch-shaped battery assembly.

In this embodiment, the thermal pad 80 is interposed between the battery cell stack 30 and the cooling plate 70 to fix the battery cell stack 30 to the cooling plate 70. According to the present invention, the thermal pad 80 is inspected for an adhesive state meaning a bonding area including an area to be bonded to the cooling plate 70 as an object to be bonded, a pressure, and the like, thereby ensuring a good bonding state under a predetermined standard.

The thermal pad 80 is a member for efficiently transferring the heat of the battery cell stack 30 to the cooling plate 70 and the cooling portion 60. The thermal pad 80 includes a battery cell stack 30 and a cooling plate 70, It may be made of an elastic material in order to improve adhesion. As one example, a heat transfer pad in which a thermally conductive material is combined with silicon may be manufactured to have a structure in which both elasticity and thermal conductivity are exerted. For example, carbon black, a copolymer, graphite, a flame retardant, and a stabilizer. The conductive polymer is a mixture of a conductive polymer and a non-conductive polymer. The conductive polymer may include polyacetylene, polythiophene, polypyrrole, poly (p-phenylene) , Poly (phenylenevinylene), poly (phenylenesulfide), and polyaniline. The non-conductive polymer is preferably selected from the group consisting of EVA (Ethylene vinyl acetate), Acrylic , POLYBUTADIENE RUBBER (BR), ACRYLONITRILE BUTADIENE RUBBER (SBR), styrene butadiene rubber (SBR), etc.), silicone series, and siloxane series. The flame retardant may be any one of magnesium hydroxide (Mg (OH) ₂ ) and aluminum hydroxide (Al (OH) ₃ ). The stabilizer may be either magnesium oxide (MgO) or zinc oxide (ZnO). The thermal pad (80) is designed to dissipate heat internally, which is used in places where the device generates heat due to the heat generated by the components, and is manufactured by various manufacturers, and a commercially available thermal pad may be purchased and applied. It is preferable to select a thermal pad having excellent thermal conductivity, stretchability, flexibility, and insulation.

The cooling plate 70 functions to transfer the heat generated from the battery cell stack 30 to the cooling unit 60 and is preferably made of a material having a high thermal conductivity for more efficient heat transfer. The material of the cooling plate 70 is not particularly limited as long as it is a thermally conductive member, for example, a metal material can be preferably used. The metal material may be aluminum or aluminum alloy having high thermal conductivity and light weight among metals, but is not limited thereto. Specifically, the cooling plate 70 may include at least one of copper, gold, silver, aluminum nitride, silicon carbide, and aluminum.

Table 1 below shows the thermal conductivity of each material capable of forming the cooling plate 70 and has a thermal conductivity of about 400 W / m.K for copper, for example, as shown in Table 1. Therefore, when the cooling plate 70 is made of copper, the heat generated in the battery cell stack body 30 at the time of charging and discharging can be rapidly transferred to the cooling unit 60, thereby enhancing the cooling efficiency.

The cooling unit 60 may be a water-cooled heat exchanger through which the cooling water passes. As the cooling water passes, the cooling part 60 maintains a low temperature state and absorbs and removes the heat transmitted through the cooling plate 70.

The method of manufacturing the battery module 100 may be as follows.

The first manufacturing method is a method in which there is no separate process step for bonding the cooling plate 70 and the thermal pad 80. In this method, the battery cell laminate 30 is placed on the thermal pad 80 and the cooling part 60 is placed on the lower part of the cooling plate 70 in a state where the thermal pad 80 is spread on the cooling plate 70, And the battery modules 100 are assembled by tightening them all at a predetermined point.

The second manufacturing method is a method in which there is a separate processing step for bonding the cooling plate 70 and the thermal pad 80. In this method, the thermal pad 80 is pressed on the cooling plate 70 in an unfolded state by a pressing means such as a roller or a plunger. Then, the battery cell stack body 30 is placed on the thermal pad 80 and the cooling unit 60 is placed on the lower side of the cooling plate 70 to form a laminate structure and then assembled into a battery module 100.

In the present invention, the step of inspecting the adhesion state of the cooling plate (70) and the thermal pad (80) is further performed in the method of manufacturing the battery module such as the first manufacturing method or the second manufacturing method, whereby the thermal pad (80) 70, the thermal pad 80 and the cooling plate 70 are adhered to each other with good adhesion at a predetermined reference level by inspecting the bonding state in a meaningful manner including a bonding area, State is secured.

In the present invention, a pressure sensitive paper is used as the adhesion state checking means. If the adhesion state is poor, the process conditions are changed and applied and evaluated. The process condition change and inspection steps can be repeated until an adhesion state satisfying a desired criterion is obtained. For example, in the first manufacturing method, the inspection step is performed by changing the fastening point or the pressure at the time of tightening. This process can be repeated until the appropriateness of the process change is evaluated and a desired degree of adhesion is obtained. In the second manufacturing method, the inspection step is performed by changing the shape, position and applied pressure of the pressing means. According to the present invention, the adhesion state between the cooling plate 70 and the thermal pad 80 is inspected through a pressure sensitive paper and applied to the process change, so that the heat radiation and adhesion efficiency of the battery module 100, including the thermal pad 80, .

It can be seen that the decompression paper is a paper whose color changes according to the state of adhesion, and is not contacted when marking does not appear. Decompression is a film that can easily and precisely confirm the pressure and flatness of a desired substrate. Fine microcapsules and a developer are applied to the film, and when pressure is applied, the color develops into a red color. The color density changes depending on the size of the pressure (the higher the color density, the higher the pressure). The amount of pressure can be determined by the eye according to the red color density. The balance of the pressure and the pressure can be checked through the distribution of the color density. On the market, there is a product called "prescale" which is produced in Fuji film. In particular, prescale is available in seven grades depending on the pressure, so it can be measured from ultrahigh pressure to extremely low pressure. The prescale is a product measuring the pressure between 0.05-02 MPa, the product measuring the pressure between 0.2-0.6 MPa, the product measuring the pressure between 0.5-2.5 MPa, the product measuring the pressure between 2.5-10 MPa, Products measuring medium pressure between 10 and 50 MPa, products measuring high pressure between 50 and 130 MPa, products measuring ultra high pressure between 130 and 300 MPa. To check the adhesion between the cooling plate 70 and the thermal pad 80, a product that measures the low pressure between 0.05 and 2.0 MPa or a product that measures the ultimate low pressure between 0.2 and 0.6 MPa may be preferred. A product measuring megapressure is provided in the form of a rolled film with a width of 310 mm, while a product measuring the ultra low pressure is provided in the form of a rolled film having a width of 270 mm. It is convenient because it can be applied to the surface to be bonded by cutting the appropriate length in the longitudinal direction of the roll in consideration of the size of the cooling plate 70 and the thermal pad 80 having a size of approximately A4 size. Using the reference chart provided for each product type, pressure can be measured by visual evaluation of color density by comparing measured pressure sensitive paper with reference chart. In order to effectively cool the battery module 100, the contact between the thermal pad 80 and the cooling plate 70 is a sensitive issue. However, in the present invention, the pressure applied to the thermal pad 80 and the cooling plate 70 is visually identified It is possible. It is suitable as an inspection means for obtaining a good bonding state between the thermal pad 80 and the entire surface of the cooling plate 70. [

FIG. 2 and FIG. 3 are views showing such an inspecting step included in the method of manufacturing a battery module according to the present invention.

First, referring to FIG. 2, a first manufacturing method without a separate process step for bonding the cooling plate 70 and the thermal pad 80 is applied. The cooling plate 70, the thermal pad 80, the pressure sensitive paper 90, and the battery cell laminate 30 are stacked in this order on the cooling portion 60 as shown in FIG. 2 (a) So that the battery module 100 is manufactured. Pressure is applied to the decompression paper 90 by a force as indicated by an arrow in the process of fastening.

Next, as shown in FIG. 2 (b), the fastening is released and the pressure-sensitive paper 90 is exposed to confirm the state. If there is a problem in the pressure-sensitive paper 90, the adhesion state is not good. Therefore, the inspection result is fed back to the manufacturing method as in the case of changing the process conditions such as the clamping point and the pressure at the time of clamping, After the battery module 100 is formed, the pressure sensitive paper 90 is inspected again as shown in FIG. 2 (b), and the appropriateness of the process condition change is examined. If not, the process of FIGS. 2 (a) and 2 (b) is again carried out and, if appropriate, applied to the manufacture of the battery module according to the modified process conditions.

Fig. 3 shows a case in which a second manufacturing method with a separate processing step for bonding the cooling plate 70 and the thermal pad 80 is applied. A thermal pad 80 and a pressure sensitive paper 90 are sequentially laminated on a cooling plate 70 as shown in FIG. 3 (a), and then a thermal pad 80 is placed on the cooling plate 70 using a pressing means 95 Press and stick. At this time, the pressing means 95 has a predetermined length in the width direction across the thermal pad 80 and may be moved in the direction of the arrow starting from one end of the thermal pad 80 as shown in the drawing.

Next, the state of the pressure-sensitive paper 90 is inspected as shown in FIG. 3 (b). It is confirmed whether or not the pressure is applied evenly along with the width and direction of the pressure means in accordance with the color change of the pressure-sensitive paper 90. Also check that the degree of pressure is adequate. If there is a problem in the pressure-sensitive paper 90, the inspection result is fed back to the manufacturing method as in the case of changing the process conditions such as the shape, position and applied pressure of the pressure means 95, The thermal pad 80 is stuck on the pressure pad 90 and then the pressure sensitive paper 90 is inspected again as shown in FIG. If not, the process of FIGS. 3 (a) and 3 (b) is again carried out and, if appropriate, applied to the manufacture of the battery module according to the modified process conditions.

As described above, in the present invention, the pressure-sensitive adhesive sheet 90 is applied to the thermal pad 80 to check the bonding state between the thermal pad 80 and the cooling plate 70. The items that can be inspected are the adhesion area (the area of the discolored area), the pressure (degree of discoloration) and the pressure uniformity (distribution of the discolored area) at the time of adhering, the fastening point of the first manufacturing method, ), Load distribution uniformity, and the like. Through such inspection, it becomes possible to grasp and control the optimum bonding condition, and it becomes possible to manufacture a battery module with improved heat dissipation and adhesion efficiency and reduced defects.

The pressure sensitive paper 90 may be a C film including an A film containing a coloring agent and a color developer. The A film is obtained by applying a coloring agent (microcapsule) to a support (PET base), and the C film is obtained by applying a coloring agent to a support (PET base). Cut the two films to the size required for the measurement, and apply pressure (or sandwich) to the reaction surface of the film (the coloring agent of each film and the surface coated with the color developer) against the measurement surface. When the microcapsules of the coloring agent layer are broken by the pressure, the coloring agent in the inside sucks the coloring agent and reacts to red color. After the pressure is applied, the decompression paper 90 is removed and the inspection is performed.

The greatest advantage of the depressurized paper 90 is that it is simple to use, and the pressure represented by the pressure-sensitive paper 90 can be quantified by using a pressure distribution mapping system program called FPD-8010E. The FPD-8010E can digitize the output from the pressure sensitive paper 90 to produce multi-plane measurement data such as pressure distribution, magnification, cross-sectional distribution, and 3D image display. Through the whole measurement, various specific parts such as mean pressure and maximum pressure can be enlarged and observed closely, so that it is possible to measure pressure and pressure uniformity. The enlargement ratio can be 4, 8, 16 times, and so on. There is also a cross line display function so that the pressure distribution on a straight line passing through a certain point can be displayed as a graph. A wire frame in which the pressure is displayed in 3D form, and the like. Rod uniformity can be assessed by displaying the load distribution as a bar graph on the upper and left side of the total pressure. The pressure of the circumference can be analyzed by the histogram. Since the pressure data is displayed in a text file, it can be output as text data. Since the gradual pressure is shown in the form of a figure, it is easy to analyze through the pressure distribution diagram. The method of use is to scan the used pressure sensitive paper 90 and analyze it using the FPD-8010E program.

By applying the decompression paper 90 in this way, the adhesion area can be visualized, and the pressure size, distribution and uniformity can be visually confirmed, so that the adhesion state can be immediately known. In other words, visual check is convenient. Since the pressure sensitive paper 90 does not require a power source and is used in accordance with the size of the object to be contacted, the pressure sensitive paper 90 can be easily measured and can be easily measured using a pressure distribution mapping system program FPD-8010E It is easy to quantify the surface pressure indicated by the shade of the surface. As a result, it is possible to improve quality and build trust. No special equipment or equipment is required and the cost is low. Since the measurement can be made at a glance within a short time, it can be introduced easily and productivity can be improved.

As described above, in the present invention, it is possible to perform various pressure analyzes through the pressure-sensitive paper 90, and can be used for solving problems concerning pressure and flatness.

On the other hand, the pressure sensitive paper 90 functions not only as a means for initial complete process setting or process change by feeding back the test result to the manufacturing method, but also as a means for performing the thermal pad adhesion step It can also be used as an experimental work means for previously checking whether a defect is detected or an accurate adhesion is performed by an operation performed at any time. For example, the decompression paper 90 can be used as a means for inspecting whether or not the process conditions are properly applied without fail even after the desired process conditions are established through the inspection step as described above. For example, after the adhesive pressure is applied to the pressure-sensitive paper 90, the state of the pressure-sensitive paper 90 is inspected to measure the pressure uniformity and the like. For example, the concentration difference of the specimen detected from the state of the pressure- If it exceeds, it is judged to be defective. Thus, the quality of the product can be assured by periodically checking the battery module during the manufacture of the battery module.

As a specific example of the step of applying the pressure sensitive paper in the second manufacturing method, the following two methods may be possible.

The first method is to apply the pressure sensitive paper 90 to the cooling plate 70 and the thermal pad 80 as described with reference to FIG. 3 and then to pressurize the pressure sensitive paper 90, particularly the roller, Is to check whether the pressure is applied evenly with the width and direction of the means. Also, check that the degree of pressure is adequate.

The result can be shown in FIG.

(a) is judged to be defective because it is judged that the roller pressure is too low at the start and end portions. (b) is judged to be good because it is judged that the thermal pad 80 is performed on the cooling plate 70 at a constant roller pressure during the whole process.

The second method is to apply the pressure sensitive paper 90 to the cooling plate 70 and the thermal pad 80 and then adjust the rollers to a specified pressure in a loose state and perform measurement. It is confirmed whether or not the pressure of the roller is uniformly applied to the specified value in accordance with the color change of the pressure sensitive paper 90. [

The result can be shown in FIG.

(a) is a case where the pressure at the center of the roller is too high, (b) is poor because the pressure decreases toward the right side of the roller, and (c) is good because the pressure is applied evenly.

By inspecting the pressure through the pressure-sensitive paper in this way, it is possible to stabilize the process and improve the quality by ensuring a uniform adhesive pressure.

FIG. 6 is an exploded perspective view of a battery module that can be manufactured by the method of manufacturing a battery module according to another embodiment of the present invention, and FIG. 7 is a schematic cross-sectional view taken along a cross section across battery cells in the battery module shown in FIG. 6 .

The battery module 200 of FIGS. 6 and 7 is particularly a case where the battery cell 110 is a pouch-shaped battery cell. A pouch-shaped battery cell is a battery cell in which an electrode assembly having a structure of a positive electrode plate, a separator, and a negative electrode plate is sealed inside a battery case together with an electrolyte, and is a plate-shaped battery cell having a generally rectangular parallelepiped structure. Such a pouch-shaped battery cell is generally composed of a pouch-shaped battery case, and the battery case includes an outer covering layer made of a polymer resin having excellent durability, a barrier layer made of a metal material exhibiting barrier properties against moisture, air, And an inner sealant layer made of a polymer resin that can be fused. The case of the pouch type battery cell may have various structures. In this embodiment, the pouch-shaped battery cell may have a structure in which the outer circumferential surface of the battery case is thermally fused and sealed with the electrode assembly embedded in the battery case of the laminate sheet including the resin layer and the metal layer. The outer circumferential surface of the pouch-shaped battery cell may be fixed between the cartridges forming the battery cell stack 130 by fixing the battery cells 110 to each other.

The battery module 200 has a structure including the battery cell stack 130, the cooling plate 170, and the cooling unit 160 including the pouch-shaped battery cells as the unit battery cells 110. The cooling plate 170 may have a structure maximizing a contact surface with air or may be processed to form an air flow path.

7, the battery cell stack 130 is interposed at the interface of the battery cells 110, and the cooling fins 130 having ends protruding from one side or both sides of the battery cell stack 130, (120).

As shown in the drawing, the battery cell 110 has a positive terminal protruded on one side of the outer circumferential surface and a negative terminal protruded on the opposite side of the battery cell 110. However, the positive electrode and the negative terminal may protrude from one side of the outer circumferential surface, The fin 120 may protrude in the direction perpendicular to the direction in which the positive and negative terminals are protruded.

The structure of the cooling fin 120 is not particularly limited as long as it is a thin, thermally conductive member, for example, a sheet of a metal material can be preferably used. The metal material may be aluminum or aluminum alloy having high thermal conductivity and light weight among metals, but is not limited thereto.

The cooling unit 160 is disposed at the protruding end of the cooling fins 120 with the cooling plate 170 therebetween so that the battery cells 110 and the cooling unit 160 are in thermal contact with each other .

The projecting ends of the cooling fins 120 are bent so as to be in close contact with the cooling plate 170. Specifically, the ends of the protruding cooling fins 120 may be bent at an angle of about 90 degrees and adhered to the cooling plate 170. [ This structure increases the contact area with the cooling plate 170 to increase the heat conduction efficiency and further improve the cooling effect. As shown in the enlarged view of FIG. 7, the cooling plate 170 is corrugated like a corrugated cardboard so as to form an air flow path between the cooling plate 160 and the cooling unit 160, thereby enabling efficient heat transfer and cooling.

The cooling plate 170 conveys the heat of the battery cells 110 through the cooling fins 120 and conducts the cooling to the cooling unit 160 to cool the battery cells 110. [ . In this embodiment, the thermal pad 180 is interposed between the cooling plate 170 and the cooling portion 160. As another example, the thermal pad 180 may be included between the protruding end of the cooling fin 120 and the cooling plate 170. According to the present invention, the thermal pad 180 is inspected for the bonding state, meaning that it includes the bonding area and the pressure with the cooling plate 170, so that a good bonding state is secured on a predetermined basis.

The battery module 200 includes a structure in which the cooling fin 120 is cooled by the cooling unit 160 when the battery cells 110 generate heat through the cooling fin 120 between the battery cells 110 The cooling efficiency can be improved with a simple cooling structure.

8 is a photograph showing an experimental example according to the present invention in which a pressure sensitive paper is applied to the manufacture of the battery module as shown in FIG.

8 (a) shows a state in which the thermal pad is adhered to the cooling plate. Although contact and degree of contact can be estimated, information on adhesion area and pressure can not be obtained.

FIG. 8 (b) shows a state in which pressure sensitive paper is applied when the cooling plate and the thermal pad are adhered according to the present invention. The contact area can be visualized by changing the color of the depressurized paper and the pressure and distribution can be determined by comparison with the reference chart. By using more dedicated programs, you can quantify the pressure at that site.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

10, 110 ... battery cells 30, 130 ... battery cell laminate
60, 160 ... cooling section 70, 170 ... cooling plate
80, 180 ... thermal pad 90 ... decompression paper
95 ... pressing means 100, 200 ... battery module
120 ... cooling pin

Claims (15)

A battery cell laminate in which battery cells are stacked;
A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack;
A cooling plate interposed between the cooling part and the battery cells; And
And a thermal pad, which is a sheet-like member provided between the battery cell stack and the cooling plate or between the cooling plate and the cooling unit and having an adhesive surface formed on both surfaces thereof, CLAIMS What is claimed is:
Disposing a thermal pad and a pressure sensitive adhesive on the surface to be adhered;
Applying pressure to the thermal pad and the pressure sensitive paper; And
And inspecting the decompression paper,
Wherein an adhesion area, a bonding pressure and a pressure uniformity of the thermal pad are measured through the area of the discolored area of the pressure sensitive paper, the degree of discoloration, and the distribution of the discolored area. The thermal pad inspection method according to claim 1, wherein the pressure sensitive sheet is a film including a film containing a coloring agent and a color developer. delete A battery cell laminate in which battery cells are stacked;
A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack;
A cooling plate interposed between the cooling part and the battery cells; And
And a thermal pad which is a sheet-like member provided between the battery cell stack and the cooling plate or between the cooling plate and the cooling unit and having an adhesive surface formed on both surfaces thereof,
The battery module is fabricated by fastening a laminated structure including the battery cell stack, the cooling unit, the cooling plate, and the thermal pad,
Inspecting an adhesion state between the thermal pad and the object to be adhered,
The step of inspecting the adhesion state includes:
Stacking the battery cell stack, the cooling unit, the cooling plate, the thermal pad, and the pressure sensitive paper, and fastening the same in accordance with the fastening method of the battery module manufacturing method; And
Disassembling the fastener and exposing the pressure sensitive paper so as to inspect the pressure sensitive paper,
The adhesion area, adhesion pressure and pressure uniformity of the thermal pad are measured through the area of the discolored area of the pressure-sensitive paper, the degree of discoloration, and the distribution of the discolored area,
Wherein the fastening point of the fastening method or the pressure at the time of fastening or the failure is detected according to the result of the measurement. delete delete A battery cell laminate in which battery cells are stacked;
A cooling unit in thermal contact with the battery cells on at least one side of the battery cell stack;
A cooling plate interposed between the cooling part and the battery cells; And
And a thermal pad which is a sheet-like member provided between the battery cell stack and the cooling plate or between the cooling plate and the cooling unit and having an adhesive surface formed on both surfaces thereof,
Placing the thermal pad on a surface to be contacted and pressing the thermal pad using a pressing means; And
Assembling a laminated structure including the battery cell stack, the cooling unit, the cooling plate, and the thermal pad to manufacture the battery module,
Inspecting an adhesion state between the thermal pad and the object to be adhered,
The step of inspecting the adhesion state includes:
Placing the thermal pad and the pressure sensitive adhesive on the surface to be adhered, and pressing the thermal pad and the pressure sensitive adhesive using the pressing means of the battery module manufacturing method; And
And inspecting the decompression paper,
The adhesion area, adhesion pressure and pressure uniformity of the thermal pad are measured through the area of the discolored area of the pressure-sensitive paper, the degree of discoloration, and the distribution of the discolored area,
Wherein a shape, a position, or an applied pressure of the pressing means is changed or a failure is detected according to a result of the measurement. The method of claim 4, wherein the step of inspecting the adhesion state is performed by changing a fastening point or a pressure at the time of fastening. 8. The method of claim 7, wherein the step of inspecting the adhesion state is performed by changing the shape, position and applied pressure of the pressing means. delete The battery pack according to claim 4 or 7, further comprising cooling fins interposed at the interface of the battery cells, the cooling fins protruding from one side or both sides of the battery cell stack body, And the battery module is mounted on the protruding end portion. The battery pack according to claim 11, wherein the battery cell has an anode and an anode terminal protruded on one side of an outer circumferential surface, or a cathode terminal protruded on one side of an outer circumferential surface, and an anode terminal protruded on an opposite side of the battery cell, And the end portion protrudes in a direction perpendicular to a direction in which the positive electrode and the negative electrode terminal protrude. 12. The method of claim 11, wherein the cooling plate is machined to form an air flow path. The battery module manufacturing method according to claim 11, wherein the battery cell is a plate-shaped battery cell, and the battery cell stack is formed by stacking the battery cells so that one surface or both surfaces of the battery cell faces the adjacent battery cells. 15. The pouch-shaped battery cell according to claim 14, wherein the plate-shaped battery cell is a pouch-shaped battery cell having a structure in which an outer periphery of a battery case is thermally fused and sealed while an electrode assembly is embedded in a battery case of a laminate sheet including a resin layer and a metal layer, Wherein the heat-sealed outer circumferential surface of the pouch-shaped battery cell is fixed between the cartridges forming the battery cell stack by fixing the battery cells to each other.

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