WO2018048133A1 - Secondary battery pouch exterior material, pouch type secondary battery using same, and manufacturing method therefor - Google Patents

Abstract

Provided are a pouch exterior material, a pouch type secondary battery using the same, and a manufacturing method therefor, the material enabling: an electrode assembly to be easily mounted at a correct position at a receiving portion; the pouch exterior material to be prevented from bursting during an assembly step while being an integrated type so as to improve lifespan characteristics of a battery by minimizing a sealing portion coming into contact with the atmosphere; and the energy density of a cell to improve. In the secondary battery pouch exterior material according to the present invention, two corresponding receiving portions on which the electrode assembly can be mounted are symmetrically formed on both sides with a protruding portion therebetween, and when in a state in which the side surface of the electrode assembly is mounted to be erected on the protruding portion, the receiving portions are bent along two folding lines separated from the central portion of the protrusion, and thus the bent portions are made to encompass the side edge of the electrode assembly.

Description

Pouch exterior material for secondary battery, pouch type secondary battery using same and manufacturing method thereof

The present invention relates to a pouch exterior material for a secondary battery, a pouch type secondary battery using the same, and a manufacturing method thereof, and more particularly, to a secondary battery pouch exterior material and a pouch type secondary using the same to improve a cell's energy density. A battery and a method for producing such a pouch type secondary battery. This application is a priority application for Korean Patent Application No. 10-2016-0117301, filed September 12, 2016, and Korean Patent Application No. 10-2017-0106833, filed August 23, 2017. All the contents disclosed in the specification and drawings of this application are incorporated in this application by reference.

Secondary batteries are widely used as a power source for mobile devices such as mobile phones, laptops and camcorders. In particular, the use of lithium secondary batteries is increasing rapidly due to the advantages of high operating voltage and high energy density per unit weight.

The lithium secondary battery mainly uses a lithium-based oxide as a positive electrode active material, a carbon material as a negative electrode active material, and is generally classified into a lithium ion battery, a lithium ion polymer battery and a lithium polymer battery, depending on the type of electrolyte used. Depending on the appearance of the battery, it may be classified into a cylindrical, square and pouch type secondary battery. Representatively, there is a high demand for rectangular secondary batteries and pouch secondary batteries that can be applied to products such as mobile phones with a thin thickness in terms of battery shape.

Among them, there is no restriction in shape and size, it is easy to assemble through thermal fusion, and the effect of exporting gas or liquid in case of abnormal behavior is easy. It is becoming. In general, a pouch type secondary battery has a structure in which an electrode assembly is embedded in a pouch case made of an aluminum laminate sheet. That is, the pouch-type secondary battery is formed of a separate aluminum laminate sheet or an extension which is separated from the aluminum laminate sheet in a state in which an accommodating part for mounting the electrode assembly is mounted on the aluminum laminate sheet and the electrode assembly is mounted on the accommodating part. It is produced by heat-sealing an aluminum laminate sheet.

Such pouch sheaths can form an enclosure by partially compressing an approximately 113 μm thick aluminum laminate sheet in a manner similar to a deep-drawing process using a die and punch. However, as described above, the aluminum laminate sheet having a thin thickness may cause rupture or the like in the process of compressing the aluminum laminate sheet, and thus it is generally difficult to form an accommodating part having a depth of 15 mm or more.

On the other hand, the separate pouch packaging material is bonded in such a way that the two units of the aluminum laminate sheet is overlapped with each other, so that the two receiving parts must be overlapped with each other in a fixed position while the electrode assembly is built in the manufacturing process of the secondary battery. If the electrode assembly is not mounted in place, an internal short circuit is caused, so a separate guide device is required, thereby increasing the manufacturing cost. In addition, since the aluminum laminate sheet of the two units are bonded on the four sides to form a sealing portion, the four sides come into contact with the atmosphere, thereby increasing the possibility of inflow of air during long-term use, thereby shortening the lifespan of the battery. Have.

In order to solve this problem, a lot of techniques have been introduced for forming a unit of two laminates corresponding to each other in the aluminum laminate sheet to overlap each other and seal the three sides.

1 is a top view of a pouch packaging material of a conventional three-side sealing pouch type secondary battery. FIG. 2 is a schematic cross-sectional view of a pouch type secondary battery manufacturing method using the pouch packaging material of FIG. 1, corresponding to section II-II ′ of FIG. 1. 3 is a top view of the pouch type secondary battery manufactured by the same method as in FIG. 2.

First, referring to FIGS. 1 and 2 (a), the storage units 20a and 20b having two shapes and sizes corresponding to two units of the pouch case 10 may be larger than the thickness of the electrode assembly 30. Forming is spaced apart by a predetermined distance (d).

Next, as shown in (b) of FIG. 2, in the state in which the electrode assembly 30 is mounted on the accommodating part 20a or 20b of one side, the center between the accommodating parts 20a and 20b as shown in FIG. The part F is bent to overlap the accommodating parts 20a and 20b as shown in FIG. 2D, and the remaining three surfaces except for the bent surface are sealed S to form the pouch type secondary battery 40 as shown in FIG. 3. ).

The manufacturing technology of the pouch type secondary battery 40 may reduce the depth t of the accommodating parts 20a and 20b formed in the pouch exterior material 10 to about half the thickness of the cell, and the four sides of the pouch type secondary battery One surface (bent center part F side) can be kept closed.

However, in the process of compressing the pouch packaging material 10 to form two adjacent housing portions 20a and 20b, the central portions F to be bent later may have the storage portions 20a and 20b on both sides. Since it is stretched and deformed so that the mechanical strength becomes weak compared with the case in which it is stretched in only one direction, it is very likely to break in forming and / or bending the receiving parts 20a and 20b. high. Therefore, the receiving parts 20a and 20b are formed to be spaced apart at a predetermined distance d, and, in consideration of the bent shape of the folded portion of the pouch case 10, is about the center portion F to be bent during folding. It is formed to have a margin of 1.5mm ~ 3mm.

Pouch type secondary batteries have high capacity and miniaturization demands from customers, and research and development of various structures and processes to realize customer needs. In particular, in the pouch type secondary battery, there are many attempts to study how to increase the battery capacity by utilizing unnecessary space to increase the capacity.

However, in the conventional three-sided sealing pouch type secondary battery 40 described with reference to FIGS. 1 to 3, unnecessary space is provided because of a margin of about 1.5 mm to 3 mm that was left around the center portion F that is bent when the pouch exterior material 10 is folded. The in-folding part w is generated and protrudes. This folding part (w) acts as a limitation of the cell capacity, lowers the energy density in the module / pack, and is disadvantageous in the cooling structure, so improvement is required.

In this way, in the pouch case of one unit, to prevent the breakage of the pouch case in the process of forming the electrode assembly accommodating portion and / or bending to overlap the accommodating portion to minimize the failure rate while improving the energy density of the cell There is a high need for a pouch packaging material that does not have unnecessary space.

The present invention was conceived in view of the above problems, and an object of the present invention is to easily mount the electrode assembly to the receiving portion in a fixed position, and to minimize the sealing portion in contact with the atmosphere to improve the life characteristics of the battery In order to provide a pouch packaging material that is integral with the pouch packaging material and prevents the pouch packaging material from being ruptured during the assembling process, and also improves the energy density of the cell.

Another object of the present invention is to provide a pouch type secondary battery using the pouch packaging material and a method of manufacturing the same.

Further objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized by the means and combinations thereof indicated in the claims.

In order to achieve the above object, the secondary battery pouch packaging material according to the present invention, two corresponding accommodating parts to which the electrode assembly can be mounted are symmetrically formed on both sides with a protrusion between the side, and the electrode assembly side When bent along the two bent lines deviated from the central portion of the protrusion in a state in which the bent portion is to surround the side edge of the electrode assembly.

The pouch sheath length between the two bends may correspond to the thickness of the electrode assembly.

The bottom edge of the housing may be inclined because the depth of the bottom edge of the housing is far greater than the depth of the bottom edge of the housing.

The upper surface width of the protrusion is greater than zero and less than the thickness of the electrode assembly.

A depth of the bottom edge away from the protrusion in the accommodating part may be 1/2 or more of the thickness of the electrode assembly. The depth of the bottom edge of the accommodating portion closer to the protrusion may be 1/2 or more of a value obtained by subtracting the width of the protrusion surface from the thickness of the electrode assembly.

It is preferable that the bottom edges near the protrusions in the both housing parts become the two bent lines.

It is preferable that the said accommodating parts do not communicate.

The outer side of the accommodating part facing the protrusion may be extended relatively.

In order to achieve the above another object, the pouch type secondary battery according to the present invention is formed on both units of the sheet-shaped pouch packaging material to which the electrode assembly can be mounted symmetrically formed on both sides with the protrusions therebetween. And bent along two bend lines away from the central portion of the protrusion in a state in which the electrode assembly side is mounted upright on the protrusion so that the bent portion surrounds the side edges of the electrode assembly while thermally sealing the accommodating parts. It is.

The length of the pouch sheath between the two bends corresponds to the thickness of the electrode assembly, so that no excess is formed between the bent portions.

The bottom edge depth of the housing portion away from the protrusion portion is 1/2 or more of the thickness of the electrode assembly, and the bottom edge depth of the side portion close to the protrusion portion of the housing portion is subtracted from the thickness of the protrusion surface by the electrode assembly thickness. It is preferable that the bottom corners close to the protruding portion in both the receiving portions become the two bends.

And, in the pouch type secondary battery manufacturing method according to the present invention, preparing a pouch case according to the present invention; Mounting the side of the electrode assembly upright on the protrusion and bending along two bend lines so that the bent portion surrounds the side edges of the electrode assembly; And heat-sealing around the nested housing parts.

Here, the pouch sheathing material has a relatively long outer side of the housing facing the protruding portion, the nesting of the housing, then heat-sealed the portions other than the outside of the housing, and injects electrolyte through the outside of the housing. After heat-sealing, the outer side of the housing may be cut.

The present invention provides a pouch packaging material that is formed to remove unnecessary space of the folding part in a three-side sealing pouch type secondary battery.

The pouch exterior material according to the present invention does not need to have a margin of about 1.5mm to 3mm considering the folding around the central area, as the existing pouch exterior material does not fold at the bottom edge side of the receiving portion, rather than folding. Conventionally, in the present invention, the bending shape of the folded portion is ducted to the side edge portion of the electrode assembly as compared to the unnecessary space generated due to the bending shape of the folding portion due to the folding of the pouch exterior material at the central portion of the side of the electrode assembly. Therefore, the electrode assembly area in the pouch case may be maximized without leaving unnecessary space in the cell, thereby improving the energy density of the cell. In addition to increasing cell capacity by eliminating unnecessary space of the folding unit, energy density of a module / pack including such a pouch type secondary battery may be increased. In addition, the unnecessary space of the folding part may be eliminated to simplify the module / pack cooling structure and the assembly process.

The pouch sheath according to the present invention can reduce the defective rate by preventing the pouch sheath from being ruptured during the manufacturing process, and can also mount the electrode assembly in place without a separate device, and minimize the sealing portion in contact with the air In addition, it is possible to further reduce the inflow of moisture and the likelihood of leakage of the electrolyte solution to improve the life characteristics of the battery.

The following drawings attached to this specification are illustrative of the preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a top view of a pouch packaging material of a conventional three-side sealing pouch type secondary battery.

FIG. 2 is a schematic cross-sectional view of a pouch type secondary battery manufacturing method using the pouch packaging material of FIG. 1, corresponding to section II-II ′ of FIG. 1.

3 is a top view of the pouch type secondary battery manufactured by the same method as in FIG. 2.

4 is an exploded perspective view of a pouch type secondary battery according to an embodiment of the present invention.

5 is a top view of the pouch packaging material included in FIG. 4.

FIG. 6 corresponds to a part of section VI-VI ′ of FIG. 5.

FIG. 7 corresponds to section VII-VII ′ of FIG. 5.

FIG. 8 is a schematic cross-sectional view of a pouch type secondary battery manufacturing method using the pouch packaging material of FIG. 5, corresponding to section VI-VI ′ of FIG. 5.

9 is a top view of the pouch type secondary battery manufactured by the same method as in FIG. 8.

FIG. 10 is a front view of the pouch packaging material in the case where the accommodating portions communicate with each other as a comparative example.

11 is a schematic cross-sectional view showing the configuration of a battery module including a pouch type secondary battery according to the present invention.

FIG. 12 is a cross-sectional view corresponding to FIG. 11, assuming a configuration of a battery module including a pouch-type secondary battery having a conventional folding unit as shown in FIG. 3, for example.

13 is a photograph of a conventional three-side sealing pouch type secondary battery.

14 and 15 are photographs of the pouch packaging material according to the present invention.

16 is a photograph of a pouch type secondary battery according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

4 is an exploded perspective view of a pouch type secondary battery according to an embodiment of the present invention. 5 is a top view of the pouch packaging material included in FIG. 4. FIG. 6 corresponds to a part of section VI-VI ′ of FIG. 5. FIG. 7 corresponds to section VII-VII ′ of FIG. 5.

First, referring to FIG. 4, the pouch type secondary battery 100 includes an electrode assembly 200 and a pouch exterior material 300.

The electrode assembly 200 may be a stacked electrode assembly in which a plurality of positive electrode plates and negative electrode plates cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween. The anode 210 and the cathode 220 of the electrode assembly 200 protrude from both sides of the pouch sheath 300 facing each other.

Two corresponding accommodating portions 310a and 310b are formed in the pouch packaging material 300 according to the present invention. The protrusion 315 is formed between the accommodating parts 310a and 310b so that the accommodating parts 310a and 310b do not communicate with each other. The width of the accommodating part 310a of one side is made of a width corresponding to the bottom surface (not shown) of the electrode assembly 200, and the width of the accommodating part 310b of the other side corresponds to the top surface 240 of the electrode assembly 200. It can consist of a width.

The upper surface width P of the protrusion 315 is greater than zero and less than the thickness t of the electrode assembly 200. Compared to the spaced apart distance considering the margin of about 1.5mm to 3mm in the gap larger than the thickness of the electrode assembly between the receiving portion, the protrusion 315 upper surface width (P) is the electrode assembly 200 thickness (t) As it is less, it is smaller than conventional.

Since the upper surface width P of the protrusion 315 should be less than the thickness t of the electrode assembly 200, in the process of compressing the pouch sheath 300 to form two adjacent receiving portions 310a and 310b, In forming the two closer portions 310a and 310b closer together, the material of the pouch sheath 300, the forming method, and the design of the forming mold are accompanied with a change so that the mechanical strength of the protrusion 315 is not weakened or ruptured. You may. However, since the forming depth is not deeper than in the related art, as shown in the experimental example described later, the pouch packaging material 300 can be manufactured without being ruptured.

Reference numerals 320, 330 and 350 denote the upper sealing portion, the lower sealing portion and the side sealing portion, respectively.

In one preferred example, the pouch sheath 300 may have a structure in which the outer sides of the accommodating portions 310a and 310b facing the protrusion 315, that is, the side sealing portion 350, extend relatively. In this case, the pouch type secondary battery 100 accommodates the electrode assembly 200 by overlapping the accommodating parts 310a and 310b, and the remaining sealing parts except for the side sealing part 350 of the extended length (the mutual contact is possible). Area), that is, the upper sealing part 320 and the lower sealing part 330 are sealed, the electrolyte is injected through the side sealing part 350, and then sealed, and the side sealing part 350 is sealed. It can be produced by cutting to the size of. By the structure of the pouch sheath 300, not only can the electrolyte be easily injected, but also the problem of overflowing the electrolyte due to an operator's mistake in the injection process can be solved.

The pouch sheath 300 may be formed of a laminate sheet including a metal layer and a resin layer. In particular, the laminate sheet may be an aluminum laminate sheet. The pouch sheath 300 is formed of a core made of a metal layer, a heat seal layer formed on an upper surface of the core portion, and an insulating film formed on a lower surface of the core portion. The heat seal layer is a polymer resin modified polypropylene, for example, CPP (Casted Polypropylene) to act as an adhesive layer, the insulating film may be formed of a resin material such as nylon or polyethylene terephthalate (PET), wherein the pouch It does not limit the structure and material of an exterior material.

The pouch sheath 300 is a deep-drawing method using a die and a punch. Through compression molding of the aluminum laminate sheet, the accommodating parts 310a and 310b may be simultaneously formed by a single process.

5 to 7, the depth t1 of the bottom edge a1 far from the protrusion 315 in the accommodating part 310a is equal to or greater than 1/2 of the thickness t of the electrode assembly 200. Similarly, the depth t1 of the bottom edge b1 far from the protrusion 315 in the accommodating part 310b is equal to or greater than 1/2 of the thickness t of the electrode assembly 200. The bottom edge (a1) depth (t1) and the bottom edge (b1) depth (t1) should be half the thickness of the electrode assembly 200 (t) is ideal because there is no remaining portion, but depending on the product for the convenience of the process It can be formed a little deeper by marginal division. Therefore, the depth t1 of the bottom edge a1 and the depth t1 of the bottom edge b1 are equal to or greater than 1/2 of the thickness t of the electrode assembly 200 having the thickness t of the electrode assembly 200.

The depth t2 of the bottom edge a2 near the protrusion 315 in the housing 310a, and the depth t2 of the bottom edge b2 near the protrusion 315 in the storage 310b. In other words, the height of the protrusion 315 is 1/2 of the thickness t of the electrode assembly 200 minus the width P of the upper surface of the protrusion.

The bottom edge a2 on the side close to the protrusion 315 in the housing portion 310a and the bottom edge b2 on the side close to the protrusion 315 in the storage portion 310b are then bent lines F1 and F2. . The accommodating part 310a of one side and the accommodating part 310b of the other side are mirror symmetric with respect to the center part F. FIG.

As shown particularly well in FIG. 6, the storage portions 310a and 310b have an inclined bottom surface. The depth t1 of the bottom edge a1 far from the protrusion 315 in the housing 310a is greater than the depth t2 of the bottom edge a2 of the side closer to the protrusion 315 in the storage 310a. Similarly, the depth t1 of the bottom edge b1 far from the protrusion 315 in the housing 310b is greater than the depth t2 of the bottom edge b2 of the side closer to the protrusion 315 in the housing 310b. Big. As the upper surface width P of the protrusion increases, the difference between the depth t1 and the depth t2 increases. On the contrary, as the protrusion upper surface width P becomes smaller, the difference between the depth t1 and the depth t2 becomes smaller. Projection upper surface width (P) may be determined in consideration of the material, elongation, etc. of the pouch packaging material (300).

Conventionally, the depths of the receiving parts correspond to about half of the thickness of the electrode assembly, and the bottom of the receiving part is not inclined. In contrast, the accommodating parts 310a and 310b of the present invention have a maximum depth of t1 and a thickness of at least 1/2 of the thickness t of the electrode assembly 200, and a minimum depth of thickness of the electrode assembly 200 as a depth t2. It is 1/2 of (t) minus the upper surface width (P) of the protrusion. The bottom surface is gradually inclined from one edge having the maximum depth to the other edge having the minimum depth.

As described above, the pouch packaging material 300 of the present invention differs from the existing pouch packaging material in forming depth and bottom shape, and the width of the protrusion between the two housing parts. The molding depth of the pouch sheath 300 of the present invention is smaller. The bottom surfaces of the accommodating portions 310a and 310b of the pouch packaging material 300 of the present invention are inclined. The width of the protrusion 315 of the pouch case 300 of the present invention is smaller.

FIG. 8 is a schematic cross-sectional view of a pouch type secondary battery manufacturing method using the pouch packaging material of FIG. 5, corresponding to section VI-VI ′ of FIG. 5. 9 is a top view of the pouch type secondary battery manufactured by the same method as in FIG. 8.

8 (a) is a cross-sectional view of the expanded state after forming the pouch packaging material 300. Thereafter, as shown in (b) of FIG. 8, the side surface 230 of the electrode assembly 200 having the thickness t is mounted on the center protrusion 315 in a state of standing and mounted with FIGS. 8 (c) and (d). In the same order, the pouch sheath 300 on both sides 310a and 310b is folded to overlap the accommodating portions 310a and 310b on both sides of the electrode assembly 200.

Referring to FIG. 4, the side surface 230 of the electrode assembly 200 is mounted on the protrusion 315 so that the anode 210 and the cathode 220 correspond to the upper sealing portion 320 and the lower sealing portion 330. The pouch sheath 300 is bent such that the upper sealing part 320, the lower sealing part 330, and the side sealing part 350 contact each other.

At this time, rather than bending the central portion F between the accommodating portions 310a and 310b as in the related art, the bending line based on the bottom edge a2 of the side closer to the protrusion 315 in the accommodating portion 310a. A bend line F2 based on the bottom edge b2 near the protrusion 315 at F1 and the receiving portion 310b, and two cutouts deviating from the central portion F of the protrusion 315 as described above. Bending along the curves F1 and F2. The length of the pouch sheath 300 between the two bend lines F1 and F2 corresponds approximately to the thickness t of the electrode assembly 200, thereby unnecessarily leaving the side surface 230 of the electrode assembly 200. Can be wrapped without The pouch packaging material 300 may be easily bent at the preformed bottom corners a2 and b2, and may be firmly sealed in a subsequent step without wrinkles or the like. As described above, in the related art, the bent portion is bent based on one bend line, which is the center portion between the two accommodating portions, and is composed of an excess portion at the center portion of the side of the electrode assembly. The difference is that there are no unnecessary parts left on the side of the electrode assembly 200 because the bent portion is bent to the side edges of the electrode assembly 200 while being bent along the bending line.

Referring to FIG. 9, unlike the related art, it may be seen that the pouch-type secondary battery 100 does not have an unnecessary portion on the right side surface, which is not sealed. As such, when the length of the pouch sheath 300 between the two bend lines F1 and F2 corresponds to the thickness t of the electrode assembly 200, no excess portion is formed between the bent portions.

If the protrusions 315 are not formed and the receiving parts 310a and 310b are completely in communication with each other, the corresponding portions of the outer circumferential surface of the pouch packaging material are deformed during bending of the pouch packaging material, and thus, a structurally stable battery is not manufactured. This can be easily confirmed in FIG. 10 in which a front view of a state in which no protrusion is formed as a comparative example is shown.

FIG. 10 is a front view of the pouch packaging material in the case where the accommodating portions communicate with each other as a comparative example.

Referring to FIG. 10, when the pouch packaging material 400 is bent based on the point A, the lower end portion 302 of the pouch packaging material 400 receives a large tensile force in the direction of the arrow. As described above, since the pouch sheath 400 is made of a laminate sheet having a very thin structure, such tensile force may cause the lower end 302 of the pouch sheath 400 to rupture.

Therefore, in the pouch packaging material 400 having the structure as shown in FIG. 10, the pouch packaging material 400 should be bent based on the point B located on the bottom surface. However, for this bending, since the deformation of the peripheral portion around the point B must be accompanied, the upper end portion 301 of the pouch packaging material 400 is deformed while bending in the direction of the point B. Therefore, a battery of a normal structure which maintains the sealing property cannot be manufactured.

However, in order to provide the protrusion 315 in the present invention, the bottom edges a2 and b2 having a predetermined depth must be formed, and the pouch sheathing material 300 is bent along the bend lines F1 and F2 based on this. The bending process does not require excessive deformation of the surrounding area.

As described above, in the present invention, while changing the forming shape of the pouch exterior material and bending along two bend lines, the bent portion is bent to surround the side edges of the electrode assembly, so that it can be stably sealed without leaving unnecessary space in the bent portion. In addition, it is possible to maximize the area of the electrode assembly in the pouch packaging material, it is possible to provide a pouch type secondary battery that can be used in high-capacity high-density electric vehicle batteries and large-capacity secondary batteries and a method of manufacturing the same.

The process of FIG. 8 (d) and then overlapping and bending the pouch case 300 so that the upper sealing part 320, the lower sealing part 330, and the side sealing part 350 of each of the upper sealing part 320 of FIG. The thermal sealing of the side sealing part 350 and the lower sealing part 330 and the sealing of the side sealing part 350 are carried out by injecting an electrolyte into the gap between the side sealing part 350. This can lead to the cutting in length.

Meanwhile, the pouch-type secondary battery 100 has been described mainly with respect to the electrode assembly 200 in which the positive electrode 210 and the negative electrode 220 protrude from each other, but with respect to the electrode assembly in which the positive electrode and the negative electrode protrude from each other. It is also possible to manufacture a pouch type secondary battery using a pouch packaging material according to the present invention.

The pouch type secondary battery 100 according to the present invention as shown in FIG. 9 may be manufactured as a module / pack by stacking several. 11 is a schematic cross-sectional view showing the configuration of a battery module including a pouch type secondary battery 100 according to the present invention.

Referring to FIG. 11, in the battery module 500, a plurality of pouch-type secondary batteries 100 may be collected so that one unsealed surface is disposed at the bottom and attached to the upper surface of the cooling plate 600. have. For example, the pouch type secondary battery 100 may be configured such that the surface corresponding to the right side in the configuration of FIG. 9 is located at the lower side, such that the surface is seated on and contacts the upper surface of the cooling plate 600. Since the surface that is not sealed has no configuration that protrudes unnecessarily compared to the surface that is sealed, the pouch type secondary battery 100 may be completely in close contact with the cooling plate 600, and the top structure of the cooling plate 600 may be simplified. .

FIG. 12 is a cross-sectional view corresponding to FIG. 11, assuming that a battery module including a pouch type secondary battery 40 having a conventional folding part w as shown in FIG. 3 is shown as a comparative example. to be.

Since the folding part w is present in the pouch-type secondary battery 40, the cooling plate 600 ′ must be a complicated shape having at least a slit as indicated by H in FIG. 12 so that the folding part w can be inserted. will be. If a cooling plate having a wider groove structure is formed to accommodate the folding portion w, the contact area between the pouch-type secondary battery 40 and the cooling plate may be small, so that sufficient cooling performance may be difficult to expect.

11 and 12, according to the configuration of the present invention, the pouch type secondary battery 100 and the cooling plate 600 may be located closer to each other than before. That is, since there is no configuration that unnecessarily protrudes from the unsealed surface, the cooling plate 600 and the pouch type secondary battery 100 may be completely in contact with each other. Therefore, it is possible to increase the energy density by reducing the volume of the entire battery module 500. In addition, according to the configuration of the present invention, the contact area between the pouch type secondary battery 100 and the cooling plate 600 can be secured to the maximum, thereby increasing heat transfer. Therefore, heat generated from the electrode assembly inside the pouch-type secondary battery 100 may be more quickly and smoothly transferred to the cooling plate 600, thereby improving cooling efficiency. In addition, in the case of FIG. 12, the assembly should be performed while fitting the folding portion w into the slit H one by one, and the present invention does not need to do so, thereby simplifying the assembly process.

13 is a photograph of a conventional three-side sealing pouch type secondary battery.

Referring to FIG. 13, the conventional three-sided sealing pouch type secondary battery 40 has a folding portion w in the three-sided sealing, the length of which is about 2.5 mm, and protrudes from the side of the electrode assembly 30.

14 and 15 is a photograph of the pouch packaging material according to the present invention, Figure 14 shows the top surface (insertion of the inner side) of the pouch packaging material 300, Figure 15 is the bottom surface of the pouch packaging material 300 (inset) Shows the outer side).

As can be seen in Figure 14 and 15, it was confirmed that in the manufacturing process of the pouch packaging material 300 according to the present invention can be formed without rupture or tearing. The receiving portions 310a and 310b and the protrusions 315 were formed as desired, and it was confirmed that they could be formed without any distortion or stress concentration at any one place.

16 is a photograph of a pouch type secondary battery according to the present invention manufactured using the pouch case 300.

As can be seen by comparing FIG. 16 and FIG. 13, in the case of the pouch type secondary battery 100 according to the present invention, there is no part that unnecessarily protrudes from the unsealed side. The flat side shape of the electrode assembly is maintained intact on the side of the pouch type secondary battery 100. As described above, in the present invention, unnecessary space is generated as shown in the folding part (w) of FIG. 13 due to the bent shape of the folding part 10 due to the folding of the pouch exterior material 10 at the central portion of the side of the electrode assembly 30. The curved shape of the folded portion of the pouch sheath 300 can be escaped to the side edge portion of the electrode assembly 200, thereby increasing the cell capacity by eliminating unnecessary space from the unsealed surface. In addition, the energy density of the module / pack including the pouch type secondary battery 100 may be increased. In addition, by eliminating unnecessary space, the module / pack cooling structure and the assembly process can be simplified.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

Claims (15)

Two corresponding receiving parts to which the electrode assembly can be mounted are symmetrically formed on both sides with the protrusion interposed therebetween, and two bent lines deviating from the central portion of the protrusion with the electrode assembly side upright mounted on the protrusion. When bent along the pouch exterior material that the bent portion surrounds the side edge of the electrode assembly. The method of claim 1, The pouch sheathing material, wherein the length of the pouch sheathing between the two bend lines corresponds to the thickness of the electrode assembly. The method of claim 1, The bottom edge of the housing is inclined so that the depth of the bottom edge away from the protrusion is greater than the depth of the bottom edge of the housing close to the protrusion. The method of claim 1, The protrusion upper surface width is greater than zero and less than the thickness of the electrode assembly, the pouch packaging material. The method of claim 1, The depth of the bottom edge away from the protruding portion in the accommodating portion is a pouch packaging material, characterized in that more than 1/2 of the thickness of the electrode assembly. The method of claim 5, The bottom edge depth of the accommodating part closer to the protruding portion is equal to or greater than 1/2 of the thickness of the electrode assembly minus the upper surface width of the protruding portion. The method of claim 5, Pouch exterior material, characterized in that the bottom corners of the sides close to the protrusions in the both housing parts become the two bent lines. The method of claim 1, A pouch packaging material, characterized in that the outer side of the receiving portion facing the protruding portion is extended relatively. Two corresponding receiving parts, on which the electrode assembly can be mounted, are formed symmetrically on both sides with a protrusion between the unit-shaped pouch packaging material, and the side of the electrode assembly is mounted on the protrusion in a state where the protrusion is mounted. A pouch type secondary battery, which is bent along two bent lines away from a center portion to cover the side edges of the electrode assembly while the bent portion surrounds the accommodating parts and heat-seaps the secondary battery. The method of claim 9, Pouch type secondary battery, characterized in that the length of the pouch sheath between the two bent lines corresponding to the thickness of the electrode assembly is not formed between the bent portion. The method of claim 9, The bottom edge depth away from the protruding portion of the accommodating portion is 1/2 or more of the thickness of the electrode assembly, The bottom edge depth of the accommodating part closer to the protrusion part is equal to or greater than 1/2 of the electrode assembly thickness minus the width of the protrusion top surface. Pouch type secondary battery characterized in that the bending line. Two corresponding receiving parts to which the electrode assembly can be mounted are symmetrically formed on both sides with the protrusion interposed therebetween, and two bent lines deviating from the central portion of the protrusion with the electrode assembly side upright mounted on the protrusion. Preparing a pouch case having the bent portion surrounding the side edges of the electrode assembly when the bent portion is bent along; Mounting the side of the electrode assembly upright on the protrusion and bending along two bend lines so that the bent portion surrounds the side edges of the electrode assembly; And Pouch-type secondary battery manufacturing method comprising the step of heat-sealing around the nested housing. The method of claim 12, The pouch sheathing material has a relatively long outer side of the accommodating part facing the protruding part, so that the accommodating parts are folded, and heat-sealed the portions except the outer side of the accommodating part, injecting electrolyte through the outer part of the accommodating part, and heat-sealing. Then, the pouch-type secondary battery manufacturing method characterized in that the outside of the receiving portion is cut. The method of claim 12, The pouch-type secondary battery manufacturing method of claim 2, wherein the length of the pouch sheath between the two bent lines corresponds to the thickness of the electrode assembly so that no excess is formed between the bent portions. The method of claim 12, The bottom edge depth away from the protruding portion of the accommodating portion is 1/2 or more of the thickness of the electrode assembly, The bottom edge depth of the accommodating part closer to the protrusion part is 1/2 of the thickness of the electrode assembly minus the width of the upper part of the protrusion part. Pouch type secondary battery manufacturing method characterized in that the curve.

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