KR102275878B1 - Method for producing cell module improved in characteristics of safety - Google Patents

Abstract

The present invention comprises the steps of: (a) arranging a plurality of cells at predetermined intervals in a cell module case; And (b) injecting a filler containing silica airgel into the cell module case to perform a foaming treatment to fill the space between the cells with silica airgel; Including, in the step (b), silica airgel Disclosed is a method for manufacturing a cell module, characterized in that after dispersing in a polymer, the dispersion is injected into the space between the cells to perform foaming treatment.

Description

Manufacturing method of cell module with improved safety {METHOD FOR PRODUCING CELL MODULE IMPROVED IN CHARACTERISTICS OF SAFETY}

The present invention relates to a method for manufacturing a cell module, and more particularly, to a method for manufacturing a cell module with improved safety by providing means for blocking fire propagation between cells when a fire occurs.

Lithium secondary batteries are widely applied to fields requiring high energy, such as automobile batteries or power storage devices, by grouping several unit cells to form one module.

However, a cell module composed of several unit cells has a problem in that when one cell is ignited, the fire is propagated to other cells adjacent thereto and a large fire occurs.

As an alternative, a method of providing a circuit for blocking the flow of current in case of a fire in the cell module has been proposed. However, when a fire occurs, high-temperature heat moves rapidly, which may cause an operation error of the circuit.

As another alternative, a technique for blocking the propagation of a fire between cells by inserting a thin pad between each cell has been proposed. In this regard, Patent Document 1 discloses a battery having a thermal insulator made of a silica airgel material, and Patent Document 2 discloses a battery module having an insulating member interposed between a plurality of battery cells to control the heat of the battery cells. This is disclosed.

However, existing fire propagation blocking technologies require a lot of work and low productivity because pad-type parts for insulation must be individually placed between each cell.

In addition, even if the pad for insulation is disposed, there is a disadvantage in that the fire may propagate to adjacent cells through a predetermined gap existing between the cell and the pad.

Patent Document 1: US Patent Registration No. 8,993,145 Patent Document 2: Korean Patent Publication No. 2014-0089456

The present invention was devised in consideration of the above problems, and a method for manufacturing a cell module capable of improving both productivity and safety by performing a process capable of collectively forming a structure capable of blocking the propagation of fire between cells Its purpose is to provide

In order to achieve the above object, the present invention comprises the steps of: (a) arranging a plurality of cells at predetermined intervals in a cell module case; And (b) injecting a filler containing silica airgel into the cell module case to perform a foaming treatment to fill the space between the cells with silica airgel; Including, in the step (b), silica airgel It provides a method for manufacturing a cell module, characterized in that after dispersing in the polymer, the dispersion is injected into the space between the cells to perform foaming treatment.

The step (b), 90% by weight of polypropylene glycol, and 1 to 2% by weight of airgel in a solution obtained by stirring a polyol component consisting of 5 to 6% by weight of water, and a disocyanate component at 1000 to 2000rpm After being added, the dispersion may be prepared by stirring at 1000 to 2000 rpm.

At least one through hole communicating with the inner space is formed in the cell module case, and it is preferable to inject the dispersion into the through hole.

In the step (b), it is preferable to form a foam having a thickness of 6 to 10 mm between the cells.

In the step (b), it is preferable to perform the foaming treatment while maintaining the internal temperature of the cell module case at 30 to 45°C.

According to another aspect of the present invention, there is provided a cell module manufactured by the method for manufacturing the cell module.

According to the present invention, it is possible to improve the safety of the cell by blocking the propagation of fire by filling the space between the cell module case and the cell, including the space between the cells, with silica airgel.

In addition, since the work efficiency can be increased by collectively filling the silica airgel in the cell module through the foaming process, there is an advantage in that productivity can be improved.

When the present invention is applied, there is no gap between the cells by the silica airgel foam, and the flat portion of each cell makes surface contact with the silica airgel, thereby effectively blocking the fire propagation between the cells.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so the present invention is described in such drawings should not be construed as being limited only to
1 is a flowchart illustrating a process in which a method of manufacturing a cell module according to a preferred embodiment of the present invention is performed.
FIG. 2 is a cross-sectional view showing the injection and foaming process of the silica airgel dispersion in FIG. 1 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

1 is a flowchart illustrating a process in which a method of manufacturing a cell module according to a preferred embodiment of the present invention is performed.

1, the cell assembly according to a preferred embodiment of the present invention comprises a cell arrangement process (step S10), a silica airgel dispersion preparation process (step S20), and a dispersion injection and foaming process (step S30 and step S40). include

In the cell arrangement process (step S10 ), a plurality of cells are arranged at predetermined intervals in a rectangular cell module case.

Each cell is preferably a battery having a plate-like body that is generally rectangular and has a thin thickness, such as a pouch-type cell. The plurality of cells are arranged in one direction and electrically connected to each other to form a cell assembly.

The pouch-type cell includes an electrode assembly embedded in a pouch case and in which positive electrodes, separators, and negative electrodes are alternately stacked. The positive electrode and the negative electrode are manufactured by applying a slurry of an electrode active material, a binder resin, a conductive agent, and other additives to at least one surface of a current collector. As the electrode active material, in the case of a positive electrode, a conventional positive electrode active material such as a lithium-containing transition metal oxide is used, and in the case of a negative electrode, lithium metal, carbon material and metal compound or mixtures thereof that can occlude and release lithium ions. A conventional negative active material may be used. In addition, as the separator, a conventional porous polymer film used in a lithium secondary battery may be employed.

As the electrolyte accommodated in the pouch case together with the electrode assembly, a conventional electrolyte for a lithium secondary battery may be employed. The pouch case is formed of a sheet material, and includes a accommodating part for accommodating the electrode assembly. Preferably, the pouch case is formed by combining the first case and the second case formed by processing a sheet material into a predetermined shape. The sheet material constituting the pouch case is the outermost resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, and an aluminum material that maintains mechanical strength and prevents penetration of moisture and oxygen It has a multi-layered structure in which a metal layer of a metal layer and an inner resin layer made of a polyolefin-based material serving as a sealing material with thermal adhesiveness are laminated.

As for the sheet material constituting the pouch case, a predetermined adhesive resin layer may be interposed between the inner resin layer and the metal layer, and the outer resin layer and the metal layer, if necessary. The adhesive resin layer is for smooth adhesion between dissimilar materials, and is formed as a single layer or multiple layers, and the material is usually a polyolefin-based resin or a polyurethane resin may be used for smooth processing, and a mixture thereof may also be employed. .

The edge of the pouch-type cell is sealed by thermocompression bonding or the like. Accordingly, the edge portion of the pouch-type cell is configured to have a relatively thin thickness compared to the body portion.

A plurality of cells are disposed with a gap in the cell module case and are electrically connected to each other in a parallel or series manner.

The silica airgel dispersion preparation process (step S20) is a process for preparing a silica airgel-containing filler to be filled in the cell module case. Specifically, in the silica airgel dispersion preparation process, 100 parts by weight of a polyol component consisting of 94 to 95 parts by weight of polypropylene glycol (PPG) and 5 to 6 parts by weight of water, and a diisocyanate component is stirred at 1000 to 2000 rpm, and then 1 to 2 parts by weight of airgel is added to the resulting solution, and then stirred at 1000 to 2000 rpm to prepare a dispersion. Here, the diisocyanate component is preferably composed of 87 parts by weight or more of diphenylmethane-4,4'-diisocyanate.

The dispersion injection process (step S30) and the foaming process (step S40) are as shown in FIG. 2 by injecting a filler corresponding to the dispersion containing the silica airgel into the inside of the cell module case 100 and foaming the cell module case ( 100) It is a series of processes to fill the empty space inside with silica airgel.

In the dispersion injection and foaming process (step S30 and step S40), the silica airgel dispersion is injected through at least one through hole 101 formed to communicate with the inner space in a part of the cell module case 100 (see arrow) to perform the foaming process carry out Here, the through hole 101 may be provided with a dedicated hole formed on one side of the cell module case 100 for injection of the dispersion. Alternatively, the through hole 101 may utilize a predetermined gas discharge hole provided in the cell module case 100 to discharge gas during the manufacturing process of the cell module. When the cell module manufacturing process is finished after the foaming process is completed, the through hole 101 is sealed and closed.

The dispersion liquid containing silica airgel injected into the cell module case 100 is filled in the space between the cell module case 100 and the cell 110 as well as the space between the cells 110 to be foamed. At this time, between the cells 110, a foam having a thickness of 6 to 10 mm, a thermal conductivity of 14.0 mW / mK or more, a density of 0.17 g / cc, a minimum use temperature of -200 ° C, and a maximum use temperature of 650 ° C is formed it is preferable

In the range where the thickness of the silica airgel foam 120 filled between the cells 110 is less than 6 mm, the blocking performance against the flame is rapidly reduced, and in the range where the thickness of the silica airgel foam 120 exceeds 10 mm, the cell ( 110) occupying a lot of space occupied by the silica airgel foam 120 interposed between them, and there is a problem that the foaming process takes too much time.

When the thermal conductivity of the silica airgel foam 120 is less than 14.0 mW / mK, heat is accumulated in a portion that is in surface contact with the cell 110 , thereby significantly reducing the performance of the cell 110 .

During the foaming process, it is preferable to perform the foaming treatment for at least 24 hours while maintaining the internal temperature of the cell module case 100 at 30 to 45°C. When the internal temperature of the cell module case 100 is less than 30 ℃, the foaming of the dispersion containing the silica airgel is not done properly, so the workability is not good, and when the internal temperature exceeds 40 ℃, the temperature of the cell 110 is excessively increased, so that the performance of the cell 110 may be deteriorated. Considering these points, the internal temperature of the cell module case 100 is most preferably maintained at 40 ℃.

Since the silica airgel foam 120 interposed between the cells 110 by the foaming process is in close contact with the adjacent cells 110, there is substantially no gap, so that the propagation of fire between the cells 110 is prevented. can be effectively blocked.

In the method for manufacturing a cell module according to a preferred embodiment of the present invention having the above configuration, a foaming process of injecting a silica airgel dispersion into the inner space through the cell module case 100 is performed to form the cell module case 100 and the cell The fire propagation prevention structure is completed by collectively filling the gaps between the cells 110, including the space between the 110, with the silica airgel foam 120.

Accordingly, as shown in FIG. 2, a plurality of cells 110 are arranged in the cell module case 100, and the silica airgel foam ( A cell module having a structure in which 120) is integrally filled is provided. As described above, the through hole 101 used for injection of the dispersion during the foaming process is sealed and closed in a subsequent process.

In order to further increase cooling efficiency, a heat transfer unit 102 made of a heat transfer material (TIM) may be added between the bottom surface of the cell module case 100 and the cells 110 .

As described above, according to the method for manufacturing a cell module according to the present invention, since the silica airgel can be collectively filled in the cell module through the foaming process, productivity can be improved.

When the present invention is applied, when any one cell 110 is ignited, it is possible to block the propagation of the fire to the adjacent cells 110 by the silica airgel foam 120, in particular, the flat portion of each cell 110. By making surface contact with the silica airgel foam 120, it is possible to block the fire propagation between the cells 110 with high efficiency. In addition, the silica airgel foaming process for the inside of the cell module case 100 can be effectively performed by the optimized foaming process conditions, and physical properties such as thickness, thermal conductivity, and density of the foam are optimized to decrease the performance of the cell 110 . It is possible to block the propagation of fire between the cells 110 without it.

In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.

100: cell module case 101: through hole
110: cell 120: silica airgel foam

Claims (6)

(a) disposing a plurality of cells at predetermined intervals in a cell module case; and
(b) injecting a filler containing silica airgel into the cell module case to perform a foaming treatment to fill the space between the cells with silica airgel;
The step (b) is,
Airgel 1-2 in a solution obtained by stirring 94 to 95 parts by weight of polypropylene glycol, 100 parts by weight of a polyol component consisting of 5 to 6 parts by weight of water, and 87 parts by weight or more of diphenylmethane-4,4'-diisocyanate A method of manufacturing a cell module, characterized in that the dispersion is injected into the space between the cells and subjected to foaming treatment after adding parts by weight and stirring. delete According to claim 1,
At least one through hole communicating with the inner space is formed in the cell module case,
A method of manufacturing a cell module, characterized in that the dispersion is injected through the through hole. According to claim 1, wherein the step (b),
A method of manufacturing a cell module, characterized in that a foam having a thickness of 6 to 10 mm is formed between the cells. 5. The method of claim 4, wherein in step (b),
Method of manufacturing a cell module, characterized in that performing the foaming treatment while maintaining the internal temperature of the cell module case at 30 ~ 45 ℃. A cell module manufactured by the manufacturing method of any one of claims 1 and 3 to 5.

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