KR20070093164A - Manufacturing process of prismatic battery - Google Patents

Abstract

A method for manufacturing a prismatic battery is provided to remove thickness difference among battery cells effectively while minimizing damage to a battery cell, to reduce working time and production costs, and to improve a working environment. A method for manufacturing a prismatic battery having an electrode assembly within a prismatic battery case comprises a step of compressing a battery cell in a thickness direction by rollers(110,120) to remove thickness difference among battery cells while transferring the battery cells on a belt conveyor(130,140), wherein the battery cell is injected with an electrolyte and sealed. The battery cell is transferred between a pair of rollers with a predetermined distance to the same direction as a movement direction of the belt conveyor and is compressed in a thickness direction at the same time.

Description

Manufacturing Process of Square Battery {Manufacturing Process of Prismatic Battery}

1 is a schematic diagram of a roller compaction apparatus according to one embodiment of the present invention;

2 and 3 are schematic views according to a modification of the compression apparatus of FIG. 1;

4 and 5 are front views of the compression apparatus of FIGS. 2 and 3;

6 is a schematic diagram of a roller compaction apparatus according to another embodiment of the present invention;

7 is a schematic view according to a modification of the compression apparatus of FIG.

The present invention relates to a method for manufacturing a rectangular battery, and more particularly, in the manufacture of a rectangular battery in which an electrode assembly is built into a rectangular battery case, a battery cell in which an electrolyte is injected and sealed is moved while moving on a belt conveyor. It provides a manufacturing method characterized in that the compression in the thickness direction to eliminate the thickness deviation.

As technology development and demand for mobile devices increase, the demand for this battery as an energy source is rapidly increasing. Secondary batteries are roughly classified into cylindrical batteries, rectangular batteries and pouch-shaped batteries according to the external and internal structural features. In recent years, with the miniaturization of mobile devices, square batteries and pouch-type batteries having a small width (thickness) to length have attracted particular attention.

An electrode assembly in which a battery reaction occurs in a secondary battery generally has a structure in which an electrolyte solution is impregnated into a cathode plate coated with a cathode active material, an anode plate coated with an anode active material, and a separator. The electrode assembly of the secondary battery is largely divided into a jelly-roll type (wound) electrode assembly and a stack type (laminated) electrode assembly according to its structure. Thus, a rectangular battery is produced by storing a jelly-roll type electrode assembly or a stacked type electrode assembly in a rectangular metal case.

In general, a rectangular battery is manufactured through an assembly process in which an electrode assembly is mounted inside a rectangular metal can and an upper insulator is mounted on an open upper end thereof, and then the base plate is welded thereon, followed by an injection of an electrolyte to seal it. At this time, the primary charge is injected to activate the battery in a state in which a predetermined amount of electrolyte is injected and the injection port is not sealed, and the secondary charge is performed after the electrolyte is injected and sealed again.

In this process, the rectangular secondary battery increases in volume in the thickness direction due to the pressure applied during sealing of the inlet and the gas generated during the secondary charging, and the increase in the thickness varies depending on the battery cells. Will cause. In this case, the increased thickness is approximately 200 μm, while the thickness of the rectangular battery is about 3.5 mm to 10 mm, which is not negligible.

In order to eliminate the thickness variation of this rectangular secondary battery, the method of pressing a battery with a metal mold | die in the state which sealed the injection hole is widely used. However, the pressing causes damage to the battery due to a strong impact since the rectangular can proceeds at a descending speed fast enough to cause plastic deformation to prevent the thickness of the battery from being restored again. For example, a phenomenon in which the active material is detached from the current collector during compression by a die, or a shape in which a welding part for electrical connection or the like is broken may appear. In addition, this pressing has a disadvantage of delaying the working time because it is made by a discontinuous process of moving the battery and lowering the mold, and noise occurs at the moment of contact between the mold and the battery cell.

Accordingly, there is a high need for a technology capable of effectively reducing the thickness variation between battery cells while preventing damage to the battery as much as possible, and simplifying the mass production process to shorten the working time and lower the manufacturing cost.

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.

After repeated studies and various experiments, the inventors of the present invention, when the battery cells are compressed in the thickness direction by using a belt conveyor and a rotating roller in the manufacturing process of the rectangular battery, effectively minimizing the damage to the battery cells between the cells In order to solve the thickness variation of the present invention, and to reduce the working time and manufacturing cost by the continuous and simple mass production process, and to confirm the advantages of improving the poor working environment such as noise and to complete the present invention. Reached.

In the manufacturing method of a square battery according to the present invention for achieving the above object, in manufacturing a square battery in which the electrode assembly is built in the square battery case, the battery cells injected with the electrolyte and sealed are rotated while moving on the belt conveyor. The roller is compressed in the thickness direction to eliminate thickness deviation.

That is, the manufacturing method according to the present invention manufactures a square battery by a compression process using a belt conveyor and a rotating roller in the overall mass production process for manufacturing the battery as one finished product.

In the manufacturing method, the belt conveyor and the rotating roller may have a variety of structures, these structures are also referred to herein as a 'roller type compression device (or compression device)'. Some preferred examples of such a roller type extrusion apparatus are as follows.

In one preferred example, the compression device consists of a pair of rotating rollers spaced at a predetermined width and a belt conveyor responsible for the movement of the battery cells on both sides thereof. The rotating roller and the belt conveyor have the same driving direction so that the battery cells can proceed continuously without changing the direction, and thus the battery cells can be compressed in the thickness direction while moving in a straight line on the belt conveyor and the rotating roller. Therefore, the compression apparatus can simplify the overall structure by simultaneously operating the belt conveyor and the rotating rollers by one drive by arranging the drive shaft of the belt conveyor and the rotating rollers in parallel, and the movement direction of the battery cell to the belt conveyor By making the same between the rollers and the rotating roller it is possible to implement a continuous compression process.

The structure in which the drive shaft of the pair of rotating rollers and the belt conveyor are arranged in parallel is more preferable in view of the ease of implementation and the maintenance of the device by the simplified structure. However, when the battery cell is introduced between the rollers, the thickness applied to the battery cell may be inhomogeneously as the pressure applied to the battery cell becomes uneven, so that the upper height of the lower roller is preferably higher than the belt conveyor. The height difference can be determined in the range of 0.5 mm to 1 mm.

As a preferred variant of the structure, the upper roller may be configured to be deflected (tilted) in the inflow direction of the battery cell with respect to the lower roller among the pair of rotary rollers of the compression device. This is because when the battery cell enters between the rotating rollers, the upper end of the lower roller is slightly higher than the height of the belt conveyor, so that the inflow direction of the battery cell cannot be maintained 90 degrees with respect to the central axis of the rotating rollers, so that partial pressure difference This can be caused. Therefore, the deflection degree is preferably an inclination in which the extension line (the central axis of the rotating rollers) of the axis of the upper roller and the axis of the lower roller can be approximately perpendicular to the inflow direction of the battery cell.

As a further variant, the rotary rollers of the compression device may consist of two or more consecutive pairs spaced apart by a predetermined width. When the battery cell is momentarily subjected to high pressure while moving between the rotating rollers, partial damage may be caused. When the battery cells are sequentially compressed by the above-described continuous rotating roller configuration, the possibility of such damage is minimized. can do. Therefore, in the above structure, it is preferable that successive roller pairs are positioned as upper and lower rollers with a sequentially narrowing width.

In another preferred example, the compression device may be comprised of a belt conveyor and a rotating roller spaced from it by a predetermined width. Therefore, the battery cell can be compressed in the thickness direction by the rotating roller while moving on the belt conveyor. In general, the belt conveyor in the form of a plate-shaped rail is subjected to a strong compressive force from the rotating roller and the battery cell during the compression process of the battery cell, it is preferable that a member (support member) for supporting the belt conveyor is installed. The support member may be installed at the lower portion of the belt conveyor at a position corresponding to the rotary roller, and its shape may vary.

As a preferred variant of the structure, the belt conveyor may be formed with an opening for mounting the battery cell, the lower portion of the belt conveyor is provided with a support member to move the battery cell mounted in the opening state In some embodiments, a rotary roller may be installed at a position spaced apart from the support member by a predetermined width on the belt conveyor. In this case, the battery cell can be compressed in the thickness direction by the rotating roller while moving on the belt conveyor in a state supported by the support member.

In the above structure, the opening is not particularly limited as long as it is a structure in which the battery cell can be mounted, and preferably, the opening may be formed in an intaglio structure on the cross section of the belt conveyor. In addition, the support member is formed not only to support the belt conveyor in the process of compressing the battery cell, but also to support the belt conveyor in the process of moving the battery cell mounted in the opening, formed throughout the lower portion of the belt conveyor It is preferable that it is done.

In the present invention, the electrode assembly is a power generator capable of charging and discharging composed of a laminated structure of the anode / separator / cathode, may be a jelly-roll-type structure wound through a separator between the long sheet-type anode and the cathode coated with the active material. It may be a stacked structure in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked in a state interposed in a separator. Among them, a jelly-roll type electrode assembly having advantages of easy manufacturing and high energy density per weight is more preferable. Since the construction and manufacturing method of such an electrode assembly are known in the art, a detailed description thereof is omitted herein.

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

1 is a schematic diagram of a roller compaction apparatus according to one embodiment of the present invention.

Referring to FIG. 1, the compression device 100 includes a pair of rotating rollers (upper rollers and lower rollers 110 and 120) spaced apart by a predetermined width, and two units that are responsible for movement of a battery cell (not shown). Belt conveyors (first belt conveyor, second belt conveyor: 130, 140). Accordingly, the battery cells that have been moved through the first belt conveyor 130 are inserted between the pair of rotating rollers 110 and 120, compressed by them, and then moved onto the second belt conveyor 140. . The pair of rotary rollers 110 and 120 and the two-unit belt conveyors 130 and 140 are arranged such that their drive shafts 111, 121, 131, and 141 are parallel to each other to move the battery cells in one direction of travel. You can.

2 and 3 are schematic diagrams according to a modification of the compression apparatus of FIG. 1, and FIGS. 4 and 5 are front views of FIGS. 2 and 3.

Referring to FIG. 2, the compression device 101 is modified such that the upper roller 110 is inclined in the inflow direction of the battery cell with respect to the lower roller 120 in the compression device 100 of FIG. 1.

The battery cell is tilted to the rotary rollers 110 and 120 to prevent the pressure applied to the battery cells from being uneven, and to move easily from the rotary rollers 110 and 120 to the second belt conveyor 140. The roller 120 has its upper end 122 mounted higher than the belt conveyors 130, 140. This may also be applied to the compression device 100 of FIG. In addition, when the battery cell is inserted between the rotary rollers (110, 120) in the first belt conveyor 130, in order to prevent the inclined insertion by the lower roller 140 higher than the first belt conveyor 130. The connection member 190 connecting the driving shaft 111 of the upper roller 110 and the driving shaft 121 of the lower roller 120 is inclined to be perpendicular to the inflow direction of the battery cell. These structures can be easily identified in FIG. 4, in which the front view of FIG. 2 is shown.

3 and 5, the compression device 102 includes three pairs of rotation rollers 110, 120, and 150 in which the rotation rollers 110 and 120 are sequentially narrowed in the compression device 100 of FIG. 1. , 160, 170, 180). At this time, the lower rollers (120, 160, 180) of the upper ends (122, 162, 182) are both installed higher than the belt conveyor (130, 140) of both units, it consists of a relationship that increases sequentially. In addition, all the upper rollers 110, 150, and 170 are inclined toward the inflow direction of the battery cell based on the respective lower rollers 120, 160, and 180.

6 is a schematic diagram of a roller compaction apparatus according to another embodiment of the present invention, Figure 7 is a schematic diagram according to a modification of the compression apparatus of FIG.

As shown in FIG. 6, the compression apparatus 200 supports the belt conveyor 210 so as to correspond to the integrated belt conveyor 210, the rotary roller 220 spaced apart from the predetermined width, and the rotary roller 220. It is composed of a support member 230. Thus, the battery cells are compressed by the rotary roller 220 while moving on the integrated belt conveyor 210. The support member 230 is positioned below the belt conveyor 210 in a state of being connected to the rotating roller 220 so as to correspond to the load acting on the belt conveyor 210 when the battery cell is compressed.

The compression apparatus 200 may support the belt conveyor 211 even when the battery cell is moved and the belt conveyor 211 having the opening 240 in which the battery cell is mounted, as shown in FIG. 7. Can be deformed into a compression device 201 composed of a support member 231, and a rotating roller 220.

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, in the manufacturing method of the square secondary battery according to the present invention by compressing the battery cells in the thickness direction by using a belt conveyor and a rotating roller, the thickness variation between the battery cells effectively while minimizing damage to the battery cells It can solve the problem, and it is possible to reduce the working time and manufacturing cost by continuous and simple mass production process, and improve the poor working environment such as noise.

Claims (10)

In the manufacturing of a rectangular battery in which the electrode assembly is built in the rectangular battery case, the battery cell in which the electrolyte is injected and sealed is compressed in the thickness direction by a rotating roller while moving on the belt conveyor, thereby eliminating the thickness variation. Way. The method according to claim 1, wherein the battery cell is compressed in a thickness direction while moving in the same traveling direction as on the belt conveyor between a pair of rotating rollers spaced at a predetermined width. The manufacturing method according to claim 2, wherein the upper height of the lower roller of the pair of rotating rollers is installed by a predetermined size higher than the height of the belt conveyor on which the battery cells are placed. 4. A method according to claim 3, wherein the height difference (difference between the top height of the lower roller and the height of the belt conveyor) is 0.5 to 1 mm. The upper roller of the pair of rotary rollers is biased (tilted) in the inflow direction of the battery cell with respect to the lower roller, wherein the degree of deflection is an extension of the axis of the upper roller and the axis of the lower roller. The manufacturing method, characterized in that the inclination is approximately perpendicular to the inflow direction of the battery cell. The method of claim 1, wherein the battery cell is compressed in a thickness direction while moving between two consecutive pairs or more rotating rollers spaced apart by a predetermined width. 7. A method according to claim 6, wherein the continuous roller pairs are positioned with upper and lower rollers at a progressively narrower separation width. The method of claim 1, wherein the battery cell is compressed in a thickness direction by a rotating roller spaced apart from the belt conveyor by a predetermined width. According to claim 1, wherein the belt conveyor is formed with an opening for mounting the battery cell, the lower portion of the belt conveyor is provided with a member (support member) for supporting the battery cell to move in the state mounted in the opening The upper part of the belt conveyor is provided with a rotating roller at a position spaced apart from the supporting member by a predetermined width, and the battery cell is compressed in the thickness direction by the rotating roller while being supported by the supporting member. Manufacturing method. The method of claim 1, wherein the electrode assembly is a jelly-roll structure.

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