KR100882488B1 - Process of Improved Productivity for Preparation of Secondary Battery - Google Patents

Abstract

The present invention relates to a method of manufacturing a secondary battery in which a plate-shaped electrode assembly is sealed together with an electrolyte solution in a sheet-shaped battery case, wherein the electrode is formed in a sheet for a battery case in which two or more storage portions in which the plate-shaped electrode assembly is formed are formed. Mounting each assembly; Heating and pressing the facing portion of the battery case to seal the remaining portions except at least one portion of each storage portion; Injecting an electrolyte into an accommodation portion through the unsealed portion; And sealing the battery case by heating and pressing the non-sealed portion, and separately cutting the battery case.

Description

Process of Improved Productivity for Preparation of Secondary Battery

1a to 1e are a series of schematic diagrams for the manufacturing process of the pouch type secondary battery according to the prior art;

FIG. 2A is a perspective view of an exemplary heating plate that may be used in the heat fusion step of the manufacturing process of FIG. 1, and FIG. 2B is a cross sectional view along its straight line B-B;

3A to 3E are schematic diagrams of a manufacturing process capable of manufacturing a plurality of secondary batteries according to one embodiment of the present invention;

4 is a perspective view of an exemplary heating roll that may be preferably applied in the heat press step of FIGS. 3B and 3D;

5A and 5B are schematic views of a heating pressurization process according to one modified example in the manufacturing process of FIG. 3.

The present invention relates to a method for manufacturing a secondary battery having improved productivity, and more particularly, in a method of manufacturing a secondary battery in which a plate-shaped electrode assembly is sealed together with an electrolyte solution in a sheet-shaped battery case, each of which includes two plate-shaped electrode assemblies embedded therein. Or attaching the electrode assembly to the battery case sheet in which more storage portions are formed; Heating and pressing the facing portion of the battery case to seal the remaining portions except at least one portion of each storage portion; Injecting an electrolyte into a storage portion through the unsealed portion; And a step of cutting the battery case separately by heating and pressing the battery case of the non-sealed portion, and separately sealing the battery cell.

As technology development and demand for mobile devices increase, the demand for batteries as energy sources is rapidly increasing, and accordingly, many studies on batteries that can meet various demands have been conducted.

Representatively, there is a high demand for rectangular secondary batteries and pouch secondary batteries, which can be applied to products such as mobile phones with a thin thickness in terms of shape of batteries, and lithium ion batteries with high energy density, discharge voltage, and output stability in terms of materials. There is a high demand for lithium secondary batteries such as lithium ion polymer batteries.

In general, a pouch type secondary battery is manufactured through a series of processes as shown in FIGS. 1A to 1E.

Referring to these drawings, the pouch type secondary battery 10 includes a laminate sheet (upper pouch 20) in which the electrode assembly accommodating portion 21 is formed and a laminate sheet (lower pouch: 30) in which the accommodating portion is not formed. With the electrode assembly 40 in the state (see FIG. 1A), one side unsealed portion (sealing) of the accommodating portion 21 in which the excess portion 50 of the upper pouch 20 and the lower pouch 30 is formed. After the heat-sealing the remaining sealing portions 61, 62, and 63 except for the predetermined portion 60 (see FIG. 1B), the electrolyte is injected through the unsealed portion 60 (see FIG. 1C), and the unsealed portion ( 60) and then cut along the dashed line AA (see FIGS. 1D and 1E).

However, since only one battery cell can be manufactured by a series of processes in this manner, there is a disadvantage in that productivity is low in manufacturing a large number of battery cells.

On the other hand, in Japanese Patent Application Laid-Open No. 2001-15099, in order to manufacture a plurality of battery cells based on the above-described manufacturing method, after separating partitions in a laminate sheet and embedding a plurality of electrode assemblies, a thermal fusion process and a cutting process Techniques for carrying out are disclosed. However, the above technology merely applies a plurality of electrode assemblies to the conventional manufacturing technology, and does not provide a specific process technology for efficiently manufacturing a plurality of battery cells. That is, for example, in the process of heat-sealing a laminate sheet in a state where a plurality of electrode assemblies are embedded, a technique for efficiently sealing an extended heat-sealing portion has not been proposed.

On the other hand, in the heat fusion process, in order to heat fusion the battery case of the laminate sheet, a heating plate as shown in Figures 2a and 2b is used.

Referring to these drawings, the heating plate 70 consists of an upper plate 71 and a lower plate 72 to which the heating wire 74 is connected, respectively, and is connected to the cylinder 73 while the lower plate 72 is fixed. The battery case (not shown) can be thermally fused by pressurizing the upper plate 71. The heating plate 70 may be formed in a shape as shown in FIG. 2A on a plane (structure of the B-B axis) so that it may be easily applied in the manufacturing process as described above.

Specifically, referring to FIGS. 1A to 1D and 2A and 2B, the remaining sealing parts 61, 62, and 63 except for the one side sealing part 60 among the facing portions of the upper pouch 20 and the lower pouch 30 may be removed. In the process of heat fusion (see FIG. 1B), the heating part 70a having a shape corresponding to the three sealing parts 61, 62, and 63 is heated by the heating wire 74a, and after the injection of the electrolyte solution, unsealing. In the process of heat-sealing the part 60 (refer FIG. 1D), the heating part 70b of the shape corresponding to the unsealed part 60 is heated through the hot wire 74b. The heating parts 70a and 70b are hollow parts 75 and sealing parts 60 corresponding to the housing part 21 and sealing parts 60, 61, 62, so that the heating parts 70a and 70b can be appropriately applied in the respective heat fusion processes (see FIGS. 1B and 1D). And a width w corresponding to 63). However, since the heating parts 70a and 70b may be applied only to a specific battery cell and a manufacturing process, the heating parts 70a and 70b may be manufactured in various structures according to the size and manufacturing process of the battery cell.

In particular, when using a heating plate for thermal fusion in the process of manufacturing a plurality of battery cells, a heating plate of a structure corresponding to the arrangement of the battery cells should be manufactured separately, in a sealing area that is not desired by a complex heating plate Since heat fusion is likely to be performed, a demanding heat fusion process is required. In addition, the heat is not evenly distributed throughout the heating plate causes a problem that the defect of the battery cell is increased.

Therefore, there is a high need for an improved manufacturing method that can be easily applied to manufacturing a plurality of battery cells.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

It is an object of the present invention to provide an improved manufacturing method for simultaneously manufacturing at least two battery cells in a single process.

Another object of the present invention is to provide a manufacturing method that can further improve the productivity of the battery cell by including a heat pressurization step with improved processability.

Still another object of the present invention is to provide a secondary battery manufactured by this method.

Manufacturing method according to the present invention for achieving this object,

In the method of manufacturing a secondary battery in which the plate-shaped electrode assembly is sealed with the electrolyte in the sheet-shaped battery case,

(a) mounting the electrode assembly on a sheet for a battery case in which two or more receiving portions each having a plate-shaped electrode assembly formed therein are formed;

(b) heating and pressing the facing portion of the battery case so as to seal the remaining portions except at least one portion of each receiving portion;

(c) injecting electrolyte into a storage portion through the unsealed portion; And

(d) heating and pressing the battery case of the non-sealed portion to seal the battery case, and separately cutting the battery case;

It is configured to include.

Therefore, the manufacturing method according to the present invention can manufacture at least two or more battery cells in a series of processes, it is possible to implement a mass production process with improved productivity.

In some cases, the battery case sheet may have various structures according to the upper sheet in which the accommodating parts are formed and the lower sheet in which the accommodating parts are not formed. For example, the upper sheet and the lower sheet may be separate members. It may be a detachable structure consisting of a, and may be a foldable (hinged) structure consisting of one member the upper sheet and the lower sheet is integrated on one side.

In one preferred example, the battery case sheet may be formed with four or more even number receiving portions. In this case, the mutually adjacent accommodating parts may be arranged to share approximately one vertex. For example, when six storage units are formed in the battery case sheet, the storage units share one vertex of two adjacent four storage units based on two storage units located at the center. It may be arranged in the form. In this case, the two storage units located in the center may be included in all four adjacent storage units of two units located in both directions, and may share a vertex in each unit storage unit. More specifically, when these storage units are described as a matrix structure, the six storage units formed in the battery case sheet may be arranged in a matrix structure of 2 3 or 3 2. Due to this structure, all the receiving portions formed in the battery case sheet are in contact with the end of the sheet on at least one side, so that the electrode assembly including the terminal for electrical connection has all terminals thereof protruding from the end of the sheet. It can be mounted in a structure.

Sharing the vertices substantially means sharing a virtual vertex located at the center of four adjacent storage units on the sheet for battery case, and not substantially sharing the vertices of the storage units.

In the present invention, the battery case sheet is particularly preferably applied to a pouch type battery made of a laminate sheet, specifically, an aluminum laminate sheet, including a resin layer and a metal layer.

In one preferred example, the heating pressurization of step (b) or step (d) may be performed by a heating plate including a heater at a position corresponding to the battery case sealing portion. Such a heating plate, as described above, may cause various problems in the process of manufacturing a plurality of battery cells, but in the process of manufacturing a few battery cells, such as when the case 4 is formed in the sheet for the battery case. It can be easily applied.

In another preferred example, the heating pressurization of process (b) or process (d) may be done by a heating roll comprising a heater. Such a heating roll may be preferably applied in a process of manufacturing a plurality of battery cells, such as when four or more storage portions are formed in the battery case sheet.

Specifically, the heating roll may be heated and pressurized while moving the sealing scheduled portion by, for example, the operation of the process controller, and in some cases, two or more heating rolls are to be sealed simultaneously by the operation of the fixed controller. It can heat-pressurize while moving a part. Therefore, the heating roll can be applied in various ways regardless of the size and arrangement of the battery cell, it is possible to maintain a constant heat and pressure in all the sealing scheduled portion, the movement is easy to improve the processability of the battery Have.

In the above example, the heating roll is not particularly limited as long as it consists of a pair of rotating rolls spaced apart by a predetermined width in a state in which the heater is embedded, and may be formed in various structures. More specifically, the heating roll is composed of an upper roll and a lower roll spaced apart by a predetermined width, and the upper roll and the lower roll are connected to the control device through the side so as not to affect the traveling direction thereof, and the control By adjusting the width and temperature spaced by the device, the sealing scheduled portion can be heated and pressurized. In addition, the upper roll and the lower roll is made of the same length with respect to each side surface, the length of the roll may vary according to the width of the sealing portion.

As an example of one preferred process according to the present invention, the battery case sheet includes a top sheet in which the accommodating parts are formed and a lower sheet in which the accommodating part is not formed, and the battery case sheet includes four accommodating members. The parts are arranged in a shape substantially sharing one vertex, and in the step (b), a process of sealing the remaining facing portions except for the opposite facing portions of the upper sheet and the lower sheet may be performed.

In detail, when the four storage units are arranged in a matrix structure of 2 2 capable of substantially sharing one vertex, in the step (b), the upper sealing unit of the first row storage units and the first row storage unit are arranged. Heat and pressure is applied to the sealing portion between the portions and the second row receiving portion, the lower sealing portion of the second row receiving portion, and the sealing portion between the first column receiving portion and the second row receiving portion, and the process (d) In this case, heating and pressing may be performed on the left sealing part of the first row receiving parts and the right sealing part of the second row receiving parts. In this case, in the process (d), the electrolyte may be injected into the four storage units from the left side of the first column receiving units and the right side of the second column receiving units, respectively.

As another example of a preferred process, the sheet for battery case is composed of a separate member of the upper sheet and the lower sheet is not formed the receiving portion is formed, the battery case sheet is four vertices in one corner Are arranged in a substantially shared form, and in the process (b), the same one side portion and two pairs of storage parts of the respective storage units may be simultaneously injected into each housing unit in one direction in the process (c). The step of sealing the remaining portions except for the portion can be performed.

In detail, when the four storage units are arranged in a matrix structure of 2 2 capable of substantially sharing one vertex, in the step (b), the upper sealing unit of the first row storage units and the first row storage unit are arranged. Heat and pressure is applied to the sealing portion between the portions and the second row receiving portion, the lower sealing portion of the second row receiving portion, and the left sealing portion of the first row receiving portion or the right sealing portion of the second row receiving portion; In step (d), heating and pressing may be performed on the sealing part between the first and second row receiving parts and the right sealing part of the second row receiving parts or the left sealing part of the first row receiving parts. In this case, in the process (d), the electrolyte may be injected into the two storage units forming the column, respectively, on the right side of the second column storage units or on the left side of the first column storage units.

The present invention also provides a secondary battery produced by this method. The secondary battery according to the present invention may be a plate-shaped secondary battery having an approximately pouch-type structure, and the plate-shaped secondary battery having such a pouch-type structure may be used as a battery cell of a small battery pack or a large battery pack.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

3A to 3C are schematic diagrams of a manufacturing process capable of manufacturing a plurality of secondary batteries according to one embodiment of the present invention.

First, referring to FIG. 3A, four electrode assemblies 400, 401, 402, and 403 are formed between an upper sheet 200 and a lower sheet 300 on which four accommodating parts 210, 211, 212, and 213 are formed. ) (See FIG. 3A).

Next, as shown in FIG. 3B, between the upper sealing part 500 of the first row receiving parts 210 and 211, the first row receiving parts 210 and 211 and the second row receiving parts 212 and 213. Between the sealing portion 510, the lower sealing portion 520 of the second row receiving portions 212 and 213, and the first column receiving portions 210 and 212 and the second column receiving portions 211 and 213. The sealing portion 540 is heated and pressurized.

In addition, as shown in FIG. 3C, four accommodating parts 210, 211, 212, and 213 are located along the arrow direction on the left side of the first column accommodating parts 210 and 212 and the right side of the second column accommodating parts 211 and 213. Inject the electrolyte into

Then, as in FIG. 3D, the left sealing part 530 of the first row receiving parts 210 and 212 and the right sealing part 550 of the second row receiving parts 211 and 213 are heated and pressurized and sealed. After that, finally, as shown in FIG.

Through this series of manufacturing process, as shown in Figure 3d, four battery cells (100, 101, 102, 103) can be manufactured at the same time.

4 schematically illustrates a perspective view of an exemplary heating roll that may be preferably applied in the heat press step of FIGS. 3b and 3d.

4, the heating roll 600 consists of a pair of upper rolls 610 and lower rolls 620, the upper rolls 610 and lower rolls 620 controlling its separation width and temperature. In order to be connected to a separate control device (not shown), which can be connected to each side (611, 621) includes a connecting shaft (630, 640). The upper roll 610 and the lower roll 620 have the same length L, the length L of which is approximately equal to the width of the sealing portions 500, 510, 520, 530, 540, 550 of FIG. 3. Do.

5A and 5B are schematic views of a heating pressurization process according to one modification in the manufacturing process of FIG. 3.

Referring to these drawings, the manufacturing process may include the upper sealing part 500 of the first row receiving parts 210 and 211, the first row receiving parts 210 and 211 and the second row receiving parts 212 and 213. A process of heating and pressing the sealing part 510 between the lower part, the lower sealing part 520 of the second row receiving parts 512 and 513, and the left sealing part 530 of the first row receiving parts 210 and 212. (See FIG. 5A); And heating the sealing portion 540 between the first row receiving portions 210 and 212 and the second row receiving portions 211 and 213, and the right sealing portion 550 of the second row receiving portions 211 and 212. Pressing may include a process (see FIG. 5B).

After the primary sealing process of FIG. 5A, when the electrolyte is injected through the right unsealed portions of the second column receiving portions 211 and 213, the accommodating portions 210 and 211 of the first row and the accommodating portions 212 of the second row are provided. , 213 can be injected at the same time.

Although described above with reference to the drawings according to an embodiment of the present invention, those of ordinary skill in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

As described above, the manufacturing method according to the present invention can produce at least two or more battery cells at the same time in one process, and further improves the productivity of the battery cells by including a heat pressurization step with improved processability. There is.

Claims (13)

In the method of manufacturing a secondary battery in which the plate-shaped electrode assembly is sealed with the electrolyte in the sheet-shaped battery case, (a) mounting the electrode assembly on a sheet for a battery case in which two or more receiving portions each having a plate-shaped electrode assembly formed therein are formed; (b) heating and pressing the facing portion of the battery case so as to seal the remaining portions except at least one portion of each receiving portion; (c) injecting electrolyte into a storage portion through the unsealed portion; And (d) heating and pressing the battery case of the unsealed portion to seal the battery case, and then cutting the battery case for each battery cell; Method of manufacturing a secondary battery comprising a. The method of claim 1, wherein the sheet for battery case is characterized in that the upper sheet in which the accommodating parts are formed and the lower sheet in which the accommodating part is not formed are formed of detachable members. The method of claim 1, wherein the battery case sheet is a manufacturing method, characterized in that the upper sheet is formed of the receiving portion and the lower sheet is not formed with a folding (hinging type) member is connected to one side. The method of claim 1, wherein the battery case sheet is provided with four or more even numbers receiving portions, and adjacent receiving portions are arranged in a form of sharing one vertex. The method of claim 1, wherein the battery case sheet is a laminate sheet comprising a resin layer and a metal layer. A method according to claim 5, wherein the sheet is an aluminum laminate sheet. The method according to claim 1, wherein the heating pressurization of step (b) or step (d) is performed by a heating plate including a heater at a position corresponding to the battery case sealing portion. . The method according to claim 1, wherein the heating pressurization of step (b) or step (d) is carried out by a heating roll including a heater. The manufacturing method according to claim 8, wherein the heating roll performs heating and pressurization while moving the sealing scheduled portion by the operation of the process control apparatus. 10. The manufacturing method according to claim 9, wherein the heating roll has a structure of a pair of rotating rolls spaced apart by a predetermined width. The method of claim 4, wherein The battery case sheet includes an upper sheet in which the accommodating parts are formed and a lower sheet in which the accommodating parts are not formed, the detachable members; Four battery compartments are arranged in the battery case sheet in such a way that they share one vertex; In the process (b), except for the opposite side portions of the upper sheet and the lower sheet, the manufacturing method, characterized in that for sealing the remaining facing portion. The method of claim 4, wherein The battery case sheet includes an upper sheet in which the accommodating parts are formed and a lower sheet in which the accommodating parts are not formed, the detachable members; Four battery compartments are arranged in the battery case sheet in such a way that they share one vertex; In the process (b), in order to simultaneously inject the electrolyte into each housing part in one direction in the process (c), in the process (b), sealing the remaining portions except for the same one portion of each storage unit and between the two pairs of the storage units. Characterized in the manufacturing method. A secondary battery manufactured by the method according to any one of claims 1 to 12.

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