KR20160115167A - Manufacturing Method of Battery Cell Having Bent Sealing Surplus Portion - Google Patents

Abstract

The present invention relates to a method of manufacturing a battery cell having bent sealed surplus portions on lateral surfaces. More specifically, the present invention relates to a battery cell designed in a structure that an electrode assembly with a cathode, anode and a separator interposed between the cathode and the anode is mounted on an accommodation unit in the battery case; a sealed surplus portion on an upper end, which is sealed by thermosetting while an electrode terminal is disposed, is included on the upper end of the battery case; and sealed surplus portions on both lateral parts which are adjacent with the sealed surplus portion on the upper end are bent and fixated on both lateral outer surfaces of the accommodation unit in the electrode assembly. Provided is the method of manufacturing battery cell comprising the steps of: (a) mounting the battery cell on a jig and overlapping and bending end units of the sealed surplus portions on the lateral surfaces towards the accommodation unit in the battery case; (b) coating an adhesive agent on the bent sealed surplus portions on the lateral surfaces; (c) vertically bending and closely attaching the adhesive agent-coated sealed surplus portions on the lateral surface to a lateral portion of the accommodation unit in the battery case; and (d) pressurizing and fixating the sealed surplus portions on the lateral surfaces which are closely attached to the lateral portion of the accommodation in the electrode assembly with a heated first block.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a battery cell having a side-

The present invention relates to a method of manufacturing a battery cell in which a side sealing surplus portion is folded.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and the like, which is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels. Therefore, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to many fields and products in the future.

Such a secondary battery may be classified as a lithium ion battery, a lithium ion polymer battery, or a lithium polymer battery depending on the configuration of an electrode and an electrolytic solution. The amount of the lithium ion polymer battery Is growing. 2. Description of the Related Art Generally, a secondary battery includes a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of a battery case, and a pouch type battery in which an electrode assembly is embedded in a pouch- , And an electrode assembly embedded in the battery case is a power generation device that includes a positive electrode, a negative electrode, and a separator structure sandwiched between the positive electrode and the negative electrode, and is capable of charging and discharging. The electrode assembly includes a long sheet-like positive electrode coated with an active material, A jelly-roll type which is wound with a separator interposed therebetween, and a stacked type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween.

Among them, due to the high capacity of the battery, enlargement of the size of the case and the processing of a thin material are attracting much attention. Accordingly, a stacked or stacked / folded type electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

Fig. 1 schematically shows a cross-sectional structure of a conventional pouch-shaped battery.

Referring to FIG. 1, the pouch type secondary battery 10 includes an electrode assembly 30 including an anode, a cathode, and a separator disposed between the anode and the cathode, 31 and 32 are sealed to be exposed to the outside.

The battery case 20 includes a case body 21 including a concave shaped storage portion 23 on which the electrode assembly 30 can be seated and a cover 22 integrally connected to the body 21 have.

The battery case 20 is made of a laminate sheet and is composed of an outer resin layer 20a forming an outermost periphery, a barrier metal layer 20b for preventing penetration of a material, and an inner resin layer 20c for sealing .

In the stacked electrode assembly 30, a plurality of positive electrode tabs 31 and a plurality of negative electrode tabs 32 are fused to each other and coupled to the electrode leads 40 and 41. In addition, when the upper end portion 24 of the case body 21 and the upper end portion of the cover 22 are thermally fused by a heat welding machine (not shown), a short circuit occurs between the heat fusion welding machine and the electrode leads 40 and 41 An insulating film 50 is attached to the upper and lower surfaces of the electrode leads 40 and 41 in order to prevent the electrode leads 40 and 41 and ensure the sealing property between the electrode leads 40 and 41 and the battery case 20.

The sealing surplus portions of the outer circumferential surface of the pouch-shaped battery cell cause an increase in the size of the battery, and thus are brought into close contact with the side surface of the electrode assembly receiving portion.

However, the above-mentioned sealing surplus portions are generally performed by hand, so that the productivity is very low, and the sealing surplus portions are restored from the side of the electrode assembly receiving portion to the state before bending, and the structural stability of the close contact state is not excellent There are problems.

Accordingly, these problems are caused by the fact that the sealing surplus portions at the upper and lower ends of the pouch-shaped battery cell have different widths, resulting in defects, thereby causing safety problems of the battery cells.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to solve the problem that surplus portions of both outer surfaces of the electrode assembly receiving portion in the battery case are restored to the state before bending from both outer surfaces of the electrode assembly receiving portion, And a side surface sealing surplus portion which is in close contact with the side portion of the electrode assembly receiving portion is pressed and fixed by a preheated block to form a battery cell and a battery cell manufacturing method .

According to an aspect of the present invention, there is provided a method of manufacturing a battery cell having a side-

An electrode assembly including a positive electrode, a negative electrode, and a separator interposed between an anode and a cathode is mounted on a receiving portion of a battery case, and an upper end sealing surplus Wherein the side sealing surplus portions on both sides adjacent to the upper end sealing portion are bent and fixed to both outer surfaces of the electrode assembly receiving portion, the method comprising:

(a) mounting the battery cell to the jig and bending the end portion of the side sealing surplus portion in the direction of the receiving portion of the battery case;

(b) applying an adhesive onto the folded side sealing pad;

(c) vertically bending and attaching the side sealing surplus portion coated with the adhesive to the side portion of the battery case receiving portion; And

(d) pressing and fixing the side sealing surplus portion closely attached to the side of the electrode assembly receiving portion by the preheated first block.

That is, in the method of manufacturing a battery cell in which the side sealing surplus portion is folded according to the present invention, the side sealing surplus portions on both sides adjacent to the housing portion of the battery case are bent to the outer surfaces on both sides of the electrode assembly housing portion, And the side sealing surplus portions are brought into close contact with the outer surface of the electrode assembly receiving portion to produce a battery cell having a uniform overall width, thereby preventing the occurrence of defects and improving the productivity.

In one specific example, the electrode assembly may have a structure in which the positive electrode terminal and the negative electrode terminal are positioned together with the upper sealing member in a horizontal plane.

In the step (a), the structure may be such that the battery cell is transferred toward the mold for bending the end portion of the side sealing surplus portion by 180 degrees toward the housing portion of the battery case.

Here, the end portion having a size of 10% to 40% may be folded in the direction of the receiving portion of the battery case, based on the width of the side sealing surplus portion.

In one specific example, the jig may include a second block that vertically bends and adheres the side seal surplus portion coated with the adhesive to the side portion of the battery case housing portion.

The length of the folded side sealing surplus portion may be 50% to 100% of the height of the battery case receiving portion.

In the step (b), the adhesive may be applied to the first side and the second side of the folded side-sealing surplus portion. The adhesive may be, for example, a urethane-based resin as the thermosetting resin.

In the step (c), the second block located below the side sealing surplus portion coated with the adhesive may be moved upward to closely contact the side of the battery case housing portion.

In such a configuration, for example, the first block may be preheated at 120 to 160 degrees Celsius and pressurized for 3 to 9 seconds at a pressure of 0.2 Mpa to 0.5 Mpa.

In addition, in the step (d), the first block may be a structure for pressing and fixing the side sealing surplus portion, which is in close contact with the side portion of the electrode assembly receiving portion, in both lateral directions.

In this case, the maximum deviation of the overall width of the upper end of the battery case and the lower end of the battery case may be in the range of 0.01 mm to 0.3 mm.

The present invention provides a battery pack including the battery cell and a device including the battery pack as a power source.

Such a device may be, for example, a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug-in hybrid electric vehicle, Or a system for power storage.

The structure and manufacturing method of such a device are well known in the art, so a detailed description thereof will be omitted herein.

As described above, in the method of manufacturing a battery cell in which the side sealing surplus portion is folded according to the present invention, in the state where the side sealing surplus portions on both sides adjacent to the housing portion of the battery case are bent on both outer sides of the electrode assembly housing portion, It is possible to solve the problem of restoring to the previous state, thereby reducing the defective rate.

1 is a schematic view of a pouch type secondary battery including a conventional stacked electrode assembly;
2 is a schematic view showing a process in which a side sealing surplus portion according to an embodiment of the present invention is bent;
Fig. 3 is a schematic view showing how the sealing surplus portion according to Fig. 2 is pressed by the second block to bend and closely contact the battery case housing portion;
4 is a schematic view showing a process in which the side sealing surplus portion of the battery case according to FIG. 3 is closely attached to the battery case housing portion;
5 is a schematic view showing a state in which the sealing surplus portion according to FIG. 4 is pressed into the preheated first block to come into close contact with the battery case housing portion;
6 is a graph showing the overall width of a battery cell according to the present invention;
7 is a schematic view showing a method of manufacturing a battery cell in which a side sealing surplus portion according to the present invention is folded.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

2 to 5 are schematic views showing that the side sealing surplus portion of the battery case according to one embodiment of the present invention is pressed and closely contacted with the first block and the second block so as to be in close contact with the battery case housing portion.

Referring to FIGS. 2 to 5, the side sealing surplus portions 125 on both sides adjacent to the upper end of the battery case 120 are folded tightly to the battery case receiving portion.

The battery cell 100 is mounted on the jig 170 and is fixed to the mold case 120 in order to bend the end portions 127 and 128 of the side sealing surplus portions 125 and 126 of the battery case 120 in the direction of the battery case housing portion 123, The end portion 127 of the side seal ingot 125 is bent 180 degrees while being conveyed in the direction of the position 180 of the side seal engaging portion 125.

The width W ₂ of the end portion 127 of the side seal ingot 125 is 30% larger than the width W ₁ of the side seal ingot 125 and overlaps in the direction of the battery case receiving portion 123 Is bent. The width W ₃ of the side seal ingot 125 has the same size as the height H ₁ of the battery case receiving portion 123. Here, a side seal Ying whether 125 width (W ₃₎ if this is larger or smaller than the height of battery case housing 123 of the adhesive force is weak and the deviation of the width increases.

The jig 170 includes a second block (not shown) for vertically bending the side sealing surplus portions 125 and 126 to which the adhesives 195 and 196 have been applied, to the side portions 123a and 123b of the battery case receiving portion 123 193, and 194, respectively.

The second blocks 193 and 194 are located below the sealing surplus portions 125 and 126. When the adhesives 195 and 196 are applied to the sealing surplus portions 125 and 126 so that the second blocks 193 and 194 move upward with respect to the ground and the sealing surplus portions 125 and 126 are inserted into the battery case receiving portion 123 The sealing surplus portions 125 and 126 are brought into close contact with the side surface portions A of the battery case housing portion 123 by bending the sealing surplus portions 125 and 126 in close contact with the side portions 123a and 123b.

The sealing abutment 125 is composed of a first surface 125a and a second surface 125b opposed thereto and the end 127 of the sealing abutment 125 has a first surface 127a and a second surface 125b, (127b).

The adhesives 195 and 196 are thermosetting urethane resins which are applied to the first surface 127a of the end portion 127 of the seal ingot 125 and the second surface 125b of the seal ingot 125, And is bent perpendicularly to the side portion 123a of the case accommodating portion 123 and tightly contacted.

That is, before the adhesive is applied and cured in the state where the end portions 127 and 128 of the sealing surplus portions 125 and 126 are overlapped and bent in the direction of the battery case containing portion 123, 123a, and 123b. Here, the opposing side seal abutment 126 is the same as the structure of the side seal abutment 125, and thus a duplicate description will be omitted.

When the side sealing surplus portions 125 and 126 are brought into close contact with the side portions 123a and 123b of the battery case housing portion 123 by the second blocks 193 and 194, Lt; / RTI >

The first block 191, 192 presses the seal ingots 125, 126 at a pressure of 130 degrees Celsius and 0.3 MPa for 6 seconds. The first blocks 191 and 192 press and fix the side seal ingots 125 and 126 which are in close contact with the side portions 123a and 123b of the electrode assembly receiving portion 123 in both lateral directions. With this structure, the deviation between the overall width G1 of the upper end of the battery case 123 and the overall width G2 of the lower end of the battery case 123 is at most 0.3 mm.

FIG. 6 is a graph showing a result of the improvement of the full width of the battery cell according to the present invention.

According to the present invention, the process capability index (Cpk) rises from 0.8 to 2.4 without increasing the full width to either side.

For reference, the Process Capability Index indicating the process capability includes Cp, Cpk, Pp, Ppk, etc., and the Process Capability Index is a ratio of the process capability to the specification, Cpk is a process capability index considering the bias in order to compensate for the disadvantage of Cp indicating the same value if the overall size does not change even if the center position is changed.

The process capability index indicates the extent to which the process capability deviates from the center of dispersion, and the higher the process capability index, the higher the accuracy is located at the center of the specification upper limit and specification lower limit.

Also, Cp represents a quantitative expression of the allowable process spread (part tolerance) for the actual process spread (natural tolerance).

Specifically, Cpk = (k-1) Cp, k = [u-M] (2 / T)

Where u denotes an average, M denotes a specification center value, T denotes a USL-LSL, and a specification upper limit (USL: LSL), wherein Cp denotes USL-LSL / Upper specification limit (LSL) and Lower specification limit (LSL) are set.

In the case of Cpk≥1.33, it is considered to have process capability. If 1.0? Cpk < 1.3, the process capability is improved but it is necessary to improve.

Referring to the graphs according to the present invention, it is confirmed that Ppk increases from 0.8 to 2.48. Cpk is the standard deviation of the short term process and Ppk is the process capability index obtained by using the overall standard deviation of the long term process including the intra-group variation of the whole sample and the inter-group variation.

Therefore, as described above, it is confirmed that the manufacturing method of the battery cell according to the present invention improves the short-term and long-term overall process capability.

7 is a flowchart showing a method of manufacturing a battery cell in which a side sealing surplus portion according to the present invention is folded.

Referring to FIG. 7, first, the battery cell is mounted on a jig, and the end portion of the side sealing surplus portion is transferred toward a mold which is bent at 180 degrees to be bent 180 degrees in the direction of the receiving portion of the battery case (S110). Then, an adhesive is applied on the first and second faces of the overlap-folded side-sealing surplus (S120), and the second block located below the side-sealing surplus portion to which the adhesive is applied is moved upward, And is vertically bent on the side portion of the pouring portion so as to be closely contacted (S130). Finally, the side sealing surplus portion closely attached to the side portion of the electrode assembly receiving portion is pressed and fixed by the preheated first block for a predetermined time (S140).

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (17)

An electrode assembly including a positive electrode, a negative electrode, and a separator interposed between an anode and a cathode is mounted on a receiving portion of a battery case, and an upper end sealing surplus Wherein the side sealing surplus portions on both sides adjacent to the upper end sealing portion are bent and fixed to both outer surfaces of the electrode assembly receiving portion, the method comprising:
(a) mounting the battery cell to the jig and bending the end portion of the side sealing surplus portion in the direction of the receiving portion of the battery case;
(b) applying an adhesive onto the folded side sealing pad;
(c) vertically bending and attaching the side sealing surplus portion coated with the adhesive to the side portion of the battery case receiving portion; And
(d) pressing and fixing the side sealing surplus portion, which is in close contact with the side portion of the electrode assembly receiving portion, with the preheated first block;
And forming a battery cell. The method as claimed in claim 1, wherein the electrode assembly has a positive electrode terminal and a negative electrode terminal positioned together in a top seal with respect to a horizontal plane. The method for manufacturing a battery cell according to claim 1, wherein in the step (a), the battery cell is transported toward a mold for bending the end portion of the side sealing surplus portion by 180 degrees toward the accommodating portion of the battery case. The method according to claim 1, wherein the end portion of the size of 10% to 40% is overlapped in the direction of the receiving portion of the battery case, based on the width of the side sealing surplus portion in the process (a). The method of manufacturing a battery cell according to claim 1, wherein the jig includes a second block that vertically bends and adheres the side seal surplus portion coated with the adhesive to the side portion of the battery case receiving portion. The method of claim 1, wherein the length of the bent side sealing surplus portion is 50% to 100% of the height of the battery case receiving portion. The method according to claim 1, wherein, in the step (b), an adhesive is applied to the first surface and the second surface of the bent side surface surplus portion. The method for manufacturing a battery cell according to claim 1, wherein the adhesive is a thermosetting resin. The method for manufacturing a battery cell according to claim 8, wherein the thermosetting resin is a urethane-based resin. The battery cell manufacturing method according to claim 1, wherein, in the step (c), the second block located below the side sealing surplus portion coated with the adhesive is moved upward and brought into close contact with the side portion of the battery case accommodating portion . 2. The method of claim 1, wherein the first block is preheated at 120 to 160 degrees Celsius. 12. The method of claim 11, wherein the first block is pressurized at a pressure of 0.2 Mpa to 0.5 Mpa for 3 seconds to 9 seconds. The method according to claim 1, wherein, in the step (d), the first block presses and fixes the side sealing surplus portion in close contact with the side portion of the electrode assembly receiving portion in both lateral directions. The method according to claim 1, wherein the maximum width of the upper end of the battery case and the lower end of the battery case is in a range of 0.01 mm to 0.3 mm. A battery pack comprising the battery cell according to claim 1. A device comprising the battery pack according to claim 15 as a power source. 17. The system of claim 16, wherein the device is a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug- , Or a system for power storage.

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