WO2019103302A1

WO2019103302A1 - Pouch-type secondary battery

Info

Publication number: WO2019103302A1
Application number: PCT/KR2018/011441
Authority: WO
Inventors: 이승환
Original assignee: 삼성에스디아이(주)
Priority date: 2017-11-21
Filing date: 2018-09-27
Publication date: 2019-05-31
Also published as: KR20190058196A; KR102143627B1

Abstract

Various embodiments of the present invention relate to a pouch-type secondary battery, and the objective of the present invention is to provide a pouch-type secondary battery capable of: improving adhesion by increasing the contact area between a sealing part and a pouch exterior; reducing the width distribution of the pouch exterior; and allowing an end portion of the sealing part to face the outer direction instead of the inner direction of the pouch exterior so as to reduce damage to the pouch exterior, caused by the end portion of the sealing part. To this end, disclosed is a pouch-type secondary battery comprising: an electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; and a pouch exterior having a first exterior part for accommodating one side of the electrode assembly, a second exterior part for accommodating the other side of the electrode assembly, and a sealing part formed to allow the first and second exterior parts to be sealed in an area corresponding to the outside of the electrode assembly, wherein the sealing part comprises: an inner folding part folded from the pouch exterior; an outer folding part folded in the outer direction from the inner folding part; and an adhesive interposed between the inner folding part and the pouch exterior.

Description

Pouch type secondary battery

Various embodiments of the present invention relate to a pouch type secondary battery.

A secondary battery is a battery that can be charged and discharged unlike a non-rechargeable primary battery. The secondary battery of low capacity is used for portable electronic devices such as smart phones, feature phones, tablet computers, notebook computers, digital cameras and camcorders, and a large-capacity secondary battery is used for motor drive power and electric power of hybrid vehicles, Storage batteries and the like.

The secondary battery may include an electrode assembly including an anode and a cathode, a case for accommodating the electrode assembly, and an electrode terminal connected to the electrode assembly. The secondary battery can be classified into a circle, a square, and a pouch type according to its shape. Among them, the pouch type secondary battery can be formed into a pouch type outer case having various shapes and easy to deform and having a small weight.

The above-described information disclosed in the background of the present invention is only for improving the understanding of the background of the present invention, and thus may include information not constituting the prior art.

A problem to be solved according to various embodiments of the present invention is to provide a sealing member which is strongly adhered to a pouch outer covering member by interposing an adhesive between the sealing portion and the pouch outer covering member to reduce scattering of the battery width, The present invention also provides a pouch type secondary battery which can prevent damage to the pouch exterior member due to the end portion of the sealing portion by folding the pouch type exterior member in a direction other than the inside direction.

The pouch type secondary battery according to various embodiments of the present invention includes an electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; And a sealing part formed by sealing the first and second external parts in a region corresponding to the outside of the electrode assembly, and a sealing part formed by sealing the first and second external parts, A pouch exterior, wherein the sealing portion includes an inner folding portion folded from the pouch exterior material and an outer folding portion folded outwardly from the inner folding portion, wherein an adhesive interposed between the inner folding portion and the pouch exterior material .

And an insulating tape adhered to an end of the outer folding portion.

The heat-melting temperature of the adhesive may be 100 ° C to 200 ° C.

The adhesive may comprise a thermoplastic resin or a thermosetting resin.

The adhesive force of the adhesive may be 200 mPa to 600 mPa.

The pouch exterior member may include a long side portion facing the long side region of the electrode assembly and a short side portion facing the short side region of the electrode assembly, the inner folding portion facing the short side portion, And the short side portion.

The pouch exterior material may further include a curved surface portion connecting the long side portion and the short side portion, wherein the inner folding portion faces the curved portion, and the adhesive may be interposed between the inner foldable portion and the curved portion.

The height of the outer folding portion may be smaller than the height of the inner folding portion.

An insulating tape is attached to the inner folding portion and the outer folding portion so that the insulating tape covers the end portion of the outer folding portion.

The various embodiments of the present invention prevent the end portion of the sealing portion from being damaged by the end portion of the sealing portion by folding the end portion of the sealing portion outward rather than the inside direction of the pouch case, The folded sealing portion can be strongly adhered to the pouch exterior member to reduce the spreading of the cell width and to prevent the bonded folded portion from hardening in the opened state before the hot melt adhesive is firmly fixed .

That is, various embodiments of the present invention provide that by providing an adhesive between the entirety of the inner folding portion of the folded sealing portion and the short side portion of the pouch exterior material, the adhesion area between the folded sealing portions and the pouch exterior material is increased . As the adhesive force is improved, the overall width of the pouch exterior member is always kept constant, thereby reducing the width scattering of a plurality of pouch type secondary batteries.

The various embodiments of the present invention also allow the outer folding portion of the folded sealing portion to be folded in the outward direction away from the pouch exterior material, not in the inward direction toward the pouch exterior material, so that the damage of the pouch exterior material by the end of the outer folding portion, So that the folding portion and the corresponding pouch exterior material are prevented from being damaged).

Also, in various embodiments of the present invention, the end of the outer folding portion of the sealing portion is finished with an insulating tape so that the metal layer is not exposed to the outside through the end of the outer folding portion. Therefore, it is possible to prevent an electrical short circuit due to the external set and the metal layer.

1A through 1C are an exploded perspective view, a plan view, and a partial perspective view of a secondary battery according to various embodiments of the present invention.

FIG. 2 is a side view illustrating folding and adhesion of a sealing part in a pouch type secondary battery according to various embodiments of the present invention. FIG.

3 is a side view illustrating folding, bonding, and taping of a sealing portion of a pouch type secondary battery according to various embodiments of the present invention.

4A to 4F are side views illustrating folding, bonding, and taping methods of a pouch type secondary battery according to various embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following drawings, thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. As used herein, the term " and / or " includes any and all combinations of one or more of the listed items. In the present specification, the term " connected " means not only the case where the A member and the B member are directly connected but also the case where the C member is interposed between the A member and the B member and the A member and the B member are indirectly connected do.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise, " and / or " comprising, " when used in this specification, are intended to be interchangeable with the said forms, numbers, steps, operations, elements, elements and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

It is to be understood that the terms related to space such as "beneath," "below," "lower," "above, But may be utilized for an easy understanding of other elements or features. Terms related to such a space are for easy understanding of the present invention depending on various process states or use conditions of the present invention, and are not intended to limit the present invention. For example, if an element or feature of the drawing is inverted, the element or feature described as "lower" or "below" will be "upper" or "above." Thus, " lower " is a concept encompassing " upper " or " lower ".

Referring to FIGS. 1A to 1C, an exploded perspective view, a plan view, and a partial perspective view of a secondary battery according to various embodiments of the present invention are shown. Here, FIG. 1A is a secondary cell before the sealing portion is folded, and FIGS. 1B and 1C are secondary cells after the sealing portion is folded.

1A to 1C, a secondary battery 100 according to various embodiments of the present invention includes an electrode assembly 110, a pouch case 120, and a pouch 120 formed outside the pouch case 120, And an adhesive 130 for bonding the

sealing portions

121b and 122b (or folding portions) of the casing member 120 to the side portions of the pouch casing member 120. [ Here, the embodiment of the present invention may further include an insulating tape (not shown) for finishing the end portions of the

sealing portions

121b and 122b.

The electrode assembly 110 may include a negative electrode plate 111, a positive electrode plate 112, and a separator 113 interposed between the negative electrode plate 111 and the positive electrode plate 112. The electrode assembly 110 may be formed by stacking the negative electrode plate 111, the separator 113, and the positive electrode plate 112, or in the form of a jelly roll.

The negative electrode plate 111 may include a negative electrode active material layer coated on both sides of a negative electrode current collector plate made of, for example, but not limited to, a conductive metal thin plate, for example, copper or nickel foil or a mesh. The negative electrode active material layer may include, for example, but not limited to, a carbon-based material, Si, Sn, a tin oxide, a tin alloy composite, a transition metal oxide, a lithium metal nitride or a metal oxide. The negative electrode uncoated portion in which the negative electrode active material layer is not formed on the negative electrode collector plate can be fixed (for example, welded) to the substantially flat negative electrode tab 114, for example, but not limited thereto. That is, one end of the negative electrode tab 114 may be electrically connected to the negative electrode uncoated portion, and the other end may protrude and extend outward. An insulating member 114a is attached to the negative electrode tab 114 to prevent the negative electrode tab 114 from being short-circuited with the pouch case 120.

The positive electrode plate 112 may include, for example, but not limited to, a positive electrode active material layer coated on both sides of a positive electrode current collector plate made of a metal thin plate having excellent conductivity, for example, an aluminum foil or a mesh. Here, the cathode active material layer may include, for example, but not limited to, chalcogenide compounds. For example, composite metal oxides such as LiCoO2, LiMn2O4, LiNiO2, and LiNiMnO2 may be used. The positive electrode tab 115 may be fixed (for example, welded) to the positive electrode uncoated portion where the positive electrode collector plate is not provided with the positive electrode active material layer, for example, but not limited thereto. An insulating member 115a is attached to the positive electrode tab 115 to prevent the positive electrode tab 115 from being short-circuited with the pouch case 120.

The separator 113 is interposed between the negative electrode plate 111 and the positive electrode plate 112 to prevent electrical shorting of the negative electrode plate 111 and the positive electrode plate 112. A pair of the separators 113 is substantially provided, and the anode plate 111 is sandwiched between the pair of separators 113. The separator 113 may be made of any one selected from the group consisting of, for example, polyethylene, polypropylene, and a porous copolymer of polyethylene and polypropylene. The separator 113 may be wider than the negative electrode plate 111 and the positive electrode plate 112 to prevent electrical shorting between the negative electrode plate 111 and the positive electrode plate 112.

The electrode assembly 110 includes a relatively long first long side 110a and a relatively long second long side 110b opposite to the first long side 110a, And four short side regions 110c connecting the two

short side regions

110a and 110b.

The pouch outer sheath 120 is formed by receiving the electrode assembly 110 and sealing the outer periphery of the electrode assembly 110. The pouch exterior member 120 may include a first exterior part 121 and a second exterior part 122, one end of which is connected to the first exterior part 121. The first enclosure 121 accommodates one side of the electrode assembly 110 (for example, the first long side region 110a of the electrode assembly 110 and a part of the short side region 110c around the first long side region 110a) And the second external portion 122 may include the first recess 121a and the second external portion 122 may be formed on the other side of the electrode assembly 110 (for example, the second long side region 110b of the electrode assembly 110 and its vicinity And a second recess 122a that receives a portion of the short side region 110c of the first recess 122a. Here, only one of the first and

second recesses

121a and 122a may be formed.

In addition, the peripheries or peripheries of the first and second

external parts

121 and 122 corresponding to the outer periphery of the electrode assembly 110 are mutually thermally fused to each other so that the electrode assembly 110 ) Are accommodated. That is, the pouch exterior member 120 is formed by bending the pouch exterior member 120 having a rectangular plate shape, which is integrally formed, about the longitudinal direction of one side and forming the first exterior part 121 and the second exterior part 122 . The first and

second enclosures

121 and 122 are provided with first and second recesses (or cavities) 121a (or 121a) having a predetermined depth at which the electrode assembly 110 can be received through a press or a drawing process, And sealing

portions

121b and 122b for sealing between the first and second

external portions

121 and 122 may be formed on the outer circumferences of the first and

second recesses

121a and 122a. The sealing

portions

121b and 122b may be formed along one side and the other side where the first and second

external portions

121 and 122 are in contact with each other.

Meanwhile, the negative electrode tab 114 and the positive electrode tab 115 of the electrode assembly 110 are drawn out to the outside through the region where the first and second

external portions

121 and 122 are fused. At this time, the insulating members 114a and 115b formed on the negative electrode tab 114 and the positive electrode tab 115 are sealed together with the sealing

portions

121b and 122b. That is, the insulating members 114a and 115b are formed at portions where the negative electrode tab 114 and the positive electrode tab 115 come in contact with the sealing

portions

121b and 122b so that the negative electrode tab 114 and the positive electrode tab 115, (120).

The pouch exterior member 120 may be formed in a multilayer or laminate structure having, for example and without limitation, a first insulation layer 120a, a metal layer 120b, and a second insulation layer 120c. Of course, a variety of adhesive layers and functional layers may be further added, but a description thereof will be omitted so as not to obscure the gist of the present invention.

The first insulating layer 120a is formed on the inner surface of the pouch case 120, and is made of a material having insulating property and heat adhesion property. The first insulating layer 120a is formed on one surface of the metal layer 120b and forms an inner surface of the pouch case 120 facing the electrode assembly 110. [ The first insulating layer 120a may be formed of a cast polypropylene film, a modified polypropylene, or the like, which does not react with an electrolyte or the like, but is not limited thereto. When the electrode assembly 110 is housed in the first and

second recesses

121a and 122a of the first and

second enclosures

121 and 122 and the first and

second enclosures

121 and 122 are folded to each other, 121 and 122 are brought into contact with each other. Accordingly, when the sealing

portions

121b and 122b are thermally fused, the first insulating layers 120a of the first and second

external portions

121 and 122 are bonded to each other to seal the pouch exterior member 120.

The metal layer 120b is sandwiched between the first insulating layer 120a and the second insulating layer 120c to prevent water and oxygen from entering from the outside and if the electrolyte is filled in the inside of the pouch case 120 , And serves to prevent the outflow thereof. In addition, the metal layer 120b serves to maintain the mechanical strength of the pouch exterior member 120. In general, the metal layer 120b may be formed of, but not limited to, aluminum, an aluminum alloy, an iron, and an iron alloy.

The second insulating layer 120c is an outer surface of the pouch outer cover 120 and serves to mitigate mechanical and chemical impacts with external electronic devices. The second insulating layer 120c is formed on the other surface of the metal layer 120b and forms the outer surface of the pouch case 120. The second insulating layer 120c may be formed of, but not limited to, nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), or the like.

Here, the metal layer 120b may be exposed to the outside through the first insulating layer 120a and the second insulating layer 120c.

The second exterior portion 122 of the pouch exterior material 120 of the secondary battery 100 according to various embodiments of the present invention includes a plurality of substantially flat short sides extending in a direction away from the second exterior portion 122, And a substantially flat long side portion 122d connected to the plurality of short side portions 122c, respectively. Furthermore, the short side portion 122c and the long side portion 122d may be connected to each other via a curved surface portion 122e. Although the short side portion 122c, the long side portion 122d and the curved side portion 122e formed in the second external portion 122 have been described above, the first external portion 121 may have the short side portion 121c, It is a matter of course that the portion 121d and the curved portion 121e can be formed (see Fig. 2). Of course, the short side portion, the long side portion and the curved portion of the first enclosure 121 may be omitted in some cases. That is, the first enclosure 121 may be entirely flat.

The

long sides

121d and 122d and the

curved portions

121e and 122e of the

short sides

121c and 122c and the first and

second recesses

121a and 122a accommodating the electrode assembly 110 Can be defined.

The sealing

portions

121b and 122b may include an inner folding portion 123a folded from the pouch jacket 120 and an outer folding portion 123b folded outwardly from the inner folding portion 123a. That is, the inner folding portion 123a is folded toward the short side portion 122c provided on the second external portion 122 of the pouch exterior material 120, for example, but not limited to, the outer folding portion 123b may be folded outwardly away from the short side 122c. In other words, the inner folding part 123a is folded in a direction substantially parallel to the short side part 122c of the pouch exterior material 120 provided on the second exterior part 122, and the outer folding part 123b is folded inward And can be folded in a direction substantially parallel to the inner folding part 123a outwardly from the folding part 123a. The folding form of the inner folding part 123a and the outer folding part 123b will be described below again.

The adhesive 130 is interposed between the inner folding part 123a and the pouch sheathing material 120 so that the inner folding part 123a does not expand to the pre-folding state due to the restoring force. That is, the adhesive 130 is interposed between the inner side folding part 123a and the short side part 122c of the pouch exterior material 120, so that the inner side folding part 123a does not extend from the short side part 122c. For example, the adhesive 130 is heated to approximately 100 to 200 占 폚 and interposed between the inner folding portion 123a and the short side portion 122c in a molten state, and then thermally compressed and cooled to be hardened. At this time, the compression tool is pressurized and bonded within about 10 seconds to about 100 to 150 占 폚 to facilitate adhesion, and thereafter is pressed again at room temperature (for example, about 10 占 폚 to 30 占 폚) It can be cooled and fixed by pressurization. Here, the heat melting temperature of the adhesive 130 may be lower than the heat sealing temperature of the lead-free polypropylene film constituting the sealing

portions

121b and 122b. Therefore, when the adhesive 130 is applied and pressed, the lead-free polypropylene film constituting the sealing

portions

121b and 122b is not remelted.

Specifically, the adhesive 130 may include a thermoplastic resin or a thermosetting resin including, for example, but not limited to, an inorganic filler (for example, silica, alumina, or boehmite).

The heat melting temperature (i.e., heat curing temperature) of the adhesive 130 may be, for example, but is not limited to, about 100 to 200 캜. However, the heat melting temperature of the adhesive 130 should be lower than the heat sealing temperature of the non-oriented polypropylene film as described above. That is, if the heat-melting temperature of the adhesive 130 is higher than the heat-sealing temperature of the unleaded polypropylene film, the sealing

portions

121b and 122b are opened during application of the folded portion by applying and pressing the molten adhesive 130 Or modified.

Further, the adhesive force of the adhesive 130 may be approximately 200 mPa to 600 mPa. If the adhesive force of the adhesive 130 is less than about 200 mPa, there is a problem that the inner folding part 123a can be stretched again from the pouch sheathing material 120. [ However, when the adhesive force of the adhesive 130 is approximately 200 mPa to 600 mPa, the inner folding part 123a does not expand from the pouch exterior material 120 again. However, if the adhesive force of the adhesive 130 is larger than approximately 600 mPa, there is a problem that the cost of purchasing the adhesive 130 increases. Here, the adhesive force of the adhesive 130 means a force when the inner folding portion 123a starts to separate from each other when pulled at an angle of about 180 from the short side portion 122c of the pouch exterior material 120 .

In addition, the thickness of the adhesive 130 is, for example, not limited, but may be approximately 1 m to 10 m. If the thickness of the adhesive 130 is less than about 1 탆, the adhesive force between the inner folding portion 123a and the pouch exterior member 120 may be reduced. If the thickness of the adhesive 130 exceeds approximately 10 mu m, the thickness of the secondary battery 100 may be unnecessarily increased.

As described above, in the various embodiments of the present invention, the adhesive 130 is further interposed between the folded sealing

portions

121b and 122b and the short side portion 122c of the pouch exterior material 120, so that the folded sealing

portions

121b, 122b and the short side portion 122c of the pouch exterior member 120 are adhered firmly to each other. Therefore, the sealing

portions

121b and 122b folded from the pouch exterior member 120 do not expand to their original positions, thereby reducing the width scattering of the pouch exterior member 120. [ The end portions of the sealing

portions

121b and 122b are double folded so as to face the outside direction of the pouch exterior member 120 and not the inside direction of the pouch exterior member 120, Can be prevented from being damaged.

That is, in the various embodiments of the present invention, the adhesive 130 is further interposed between the entire inner folding part 123a of the sealing

parts

121b and 122b and the pouch exterior material 120, So that the adhesion between the sealing

portions

121b and 122b and the pouch exterior member 120 is improved. As the adhesive force is improved, the entire width of the pouch exterior member 120 is kept constant, thereby decreasing the width scattering of each pouch type secondary battery. Also, in various embodiments of the present invention, the outer folding portion 123b of the sealing

portions

121b, 122b is folded outwardly away from the pouch exterior material 120, not inwardly toward the pouch exterior material 120, The damage of the pouch exterior member 120 due to the end of the portion 123b is prevented. For example, damage to the inner folding portion 123a due to the end portion of the outer folding portion 123b and a corresponding portion of the pouch outer covering member 120 are prevented.

Referring to FIG. 2, there is shown a side view of folding and adhesion of a sealing portion of a pouch type secondary battery according to various embodiments of the present invention.

2, the pouch skin member 120 includes a first skin 121 covering the upper part of the electrode assembly 110, a second skin 122 covering the lower portion of the electrode assembly 110, And sealing

portions

121b and 122b formed by sealing the first and second

external portions

121 and 122 in a region corresponding to the outside of the electrode assembly 110. [

The sealing

portions

121b and 122b include an inner folding portion 123a folded downward from the pouch exterior member 120 and an outer folding portion 123b folded upward and outward from the inner folding portion 123a . Here, the outward direction is not an area between the inner folding part 123a and the short side 122c of the pouch exterior material 120 (i.e., the short side 122c of the second enclosure 122) And the outer side of the inner folding part 123a away from the inner folding part 122c.

Further, the adhesive 130 (130) is provided between the inner folding portion 123a of the sealing

portions

121b and 122b and the short side portion 122c of the pouch exterior material 120 (i.e., the short side portion 122c of the second exterior portion 122) ) Are further intervened. When the inner folding portions 123a of the sealing

portions

121b and 122b extend to the curved surface portion 122e of the pouch exterior material 120 (that is, the curved surface portion 122e of the second exterior portion 122) The adhesive 130 may also be filled between the inner folding part 123a and the curved part 122e of the pouch exterior material 120.

The inner folding portions 123a of the sealing

portions

121b and 122b are firmly / firmly adhered to the short side portion 122c of the pouch exterior member 120 by the adhesive agent 130 so as to seal the sealing

portions

121b and 122b. The inner folding part 123a of the pouch exterior member 120 does not expand outwardly. Therefore, the width dispersion for a plurality of secondary batteries is reduced. The adhesive layer 130 is formed on the entire inner surface of the inner folding part 123a facing the short side 122c of the pouch outer cover 120 so that the short side 122c and the inner folding part 122c of the pouch outer casing 120 The inner folding portion 123a is not separated from the short side portion 122c of the pouch exterior material 120. As a result,

The outer folding part 123b of the sealing

parts

121b and 122b is folded outside the inner folding part 123a not between the inner folding part 123a and the short side part 122c, It is possible to prevent damage to the pouch exterior member 120 due to the end portion of the pouch exterior member 120. [ That is, when the outer folding part 123b is folded inwardly between the inner folding part 123a and the short side part 122c, the end of the outer folding part 123b is pressed against the outer surface of the pouch case 120, The embodiment of the present invention allows the outer folding portion 123b to be directed to the outside rather than the inside, thereby making it possible to fundamentally prevent the above-described problem.

Referring to FIG. 3, there is shown a side view of folding, bonding, and taping of a sealing portion of a pouch type secondary battery according to various embodiments of the present invention.

As shown in FIG. 3, an insulating tape 140 may be further adhered to an end of the outer folding part 123b. That is, a series of insulating tapes 140 are further adhered to the inner folding part 123a and the outer folding part 123b, so that the insulating tape 140 covers the end of the outer folding part 123b. Here, the end of the outer folding part 123b means the upper end of the figure.

As described above, the metal layer may be exposed to the outside through the end of the outer folding part 123b. However, as described above, since the insulating tape 140 is further adhered to the end of the outer folding part 123b, the metal layer is not exposed to the outside, and thus unnecessary electrical connection between the metal layer and the external device The contact is blocked. The outer folding part 123b and the inner folding part 123a are covered with the insulating tape 140 so that the outer folding part 123b does not expand outward but is kept in close contact with the inner folding part 123a . Therefore, the width scattering for a plurality of secondary batteries is further reduced.

In addition, the height (or the vertical length) of the outer folding part 123b is preferably smaller than the height (or the vertical length) of the inner folding part 123a. That is, if the height of the outer folding part 123b is equal to or larger than the height of the inner folding part 123a, there is a risk that the process control is difficult and the end portion thereof passes through the insulating tape 140.

The insulation tape 140 substantially covers both the short side 121c and the curved side 121e of the first external casing 121 and the curved side 122e of the second external casing 122, The folding portion 123a and the outer folding portion 123b may not be extended outward.

4A-4F, a side view of folding, gluing, and taping methods of a pouch type secondary battery according to various embodiments of the present invention is shown.

4A, an electrode assembly (not shown) is housed inside the pouch case 120, that is, inside the first and second

external parts

121 and 122, and then the pouch case 130, which corresponds to the outside of the electrode assembly, The sealing

portions

121b and 122b are formed in a substantially horizontal shape along the periphery of the pouch outer casing 120. [ That is, sealing

portions

121b and 122b extending outward in the horizontal direction are formed along the periphery of the pouch exterior member 120. [

Next, as shown in FIG. 4B, one side of the sealing

portions

121b and 122b is folded upward and inward to form an outer folding portion 123b. The length of the outer folding part 123b is shorter than the length of the remaining sealing

parts

121b and 122b such that the length of the outer folding part 123b is smaller than that of the inner folding part 123a.

Next, as shown in FIG. 4C, the other of the sealing

portions

121b and 122b is folded downward to form an inner folding portion 123a. That is, by folding the sealing

portions

121b and 122b extending from the pouch exterior member 120 in the lower direction, the short side portion 122c of the pouch exterior member 120 (i.e., the short side portion 122c of the second exterior portion 122 ) Is formed in the inner folding part 123a.

4D, an adhesive 130 is injected between the inner folding portion 123a of the sealing

portions

121b and 122b and the short side portion 122c of the pouch exterior material 120. As shown in FIG.

The viscosity of the adhesive 130 may be about 5,000 mPa · s to 10,000 mPa · s so that the adhesive 130 can be easily injected between the inner folding part 123a and the short side part 122c.

If the viscosity of the adhesive 130 is less than about 5,000 mPa.s, the adhesive 130 may easily flow into other areas during the filling process of the adhesive 130, causing a problem of contamination, and the viscosity of the adhesive 130 may be about 10,000 mPa · s, it takes a long time to fill the adhesive 130 between the inner folding portion 123a and the short side portion 122c, or the adhesive 130 is not filled.

Also, in order to liquefy the solid adhesive and maintain the viscosity, the adhesive vessel and the feed syringe can be heated to approximately 100 ° C to 200 ° C. That is, when the temperature of the adhesive container and the supply syringe is lower than about 100 ° C, the solid adhesive is not sufficiently phase-changed to the liquid adhesive, and the viscosity is higher than about 10,000 mPa · s, It is difficult to inject into the gap between the part and the pouch exterior. Further, when the temperature of the adhesive container and the supply syringe is higher than about 200 ° C, the viscosity of the adhesive becomes higher than about 5,000 mPa · s, so that the adhesive injected into the gap between the inner folding portion and the pouch exterior member can easily flow into another region, Ambient pollution problems can occur.

Subsequently, when filling of the molten adhesive 130 is completed between the inner folding part 123a and the short side part 122c, the inner folding part 123a and the outer folding part 123c are pressed by using a thermocompression pressing tool before the adhesive hardens, The portion 123b is pressed toward the short side portion 122c. The adhesive is melted and supplied at a temperature of approximately 100 ° C to 200 ° C, and may exist in a solid state at room temperature. At this time, the thermocompression pressing tool presses the inner folding portion 123a and the outer folding portion 123b toward the short side portion 122c of the pouch exterior member within about 10 seconds to about 100 ° C to 150 ° C to facilitate the adhesion.

If the temperature of the thermocompression pressing tool is lower than about 100 캜, the adhesive 130 may be completely cured and fixed in a widened state before the inner folding portion and the short side portion are attached. If the temperature of the thermocompression tool is about 150 캜 If it is too high, the curing operation of the adhesive may not be performed or the lead-free polypropylene film constituting the sealing

portions

121b and 122b may be remelted. When the lead-free polypropylene filament film is remelted in this manner, the sealing portion can be opened, weakened or deformed.

Then, as shown in FIG. 4E, when the pressing by the thermocompression pressing tool is completed, the cooling and pressing tool operates for hardening and cooling of the adhesive 130. For example, the cooling and pressing tool may have an inner folding portion 123a and an outer folding portion 123b at a short side portion of the pouch exterior member (for example, about 10 to about 30 seconds) at a room temperature of about 10 ° C to 30 ° C to facilitate curing and cooling of the adhesive. 122c.

Here, the thermocompression pressing tool and the cooling pressurizing tool may be the same tool capable of adjusting the temperature range, or may be tools provided separately from each other.

As a result, the adhesive 130 is hardened by the thermocompression process, so that the inner folding portion 123a is firmly adhered to the short side portion 122c. That is, the inner folding portion 123a does not extend outward from the short side portion 122c.

Finally, as shown in FIG. 4F, an insulating tape 140 is further attached between the outer folding part 123b and the inner folding part 123a. That is, the outer folding part 123b and the inner folding part 123a including the end of the outer folding part 123b are finished with the insulating tape 140 so that the end of the outer folding part 123b is not exposed to the outside do. The outer folding part 123b is not expanded in the horizontal direction by the insulating tape 140 and the metal layer is not exposed to the outside through the end of the outer folding part 123b so that the electrical short between the metal layer and the external device The phenomenon is also prevented.

As described above, the pouch type secondary battery according to the present invention is only one embodiment, and the present invention is not limited to the above-described embodiment, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

An electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; And

A pouch having a first external portion accommodating one side of the electrode assembly, a second external portion accommodating the other side of the electrode assembly, and a sealing portion formed by sealing the first and second external portions in a region corresponding to the outside of the electrode assembly, Comprising an exterior material,

Wherein the sealing portion includes an inner folding portion folded from the pouch exterior material and an outer folding portion folded outwardly from the inner folding portion and an adhesive interposed between the inner folding portion and the pouch exterior material, Pouch type secondary battery.
The method according to claim 1,

And an insulating tape adhered to an end of the outer folding part.
The method according to claim 1,

Wherein the thermal melting temperature of the adhesive is lower than the thermal fusion temperature of the sealing portion.
The method according to claim 1,

Wherein the adhesive has a thermal melting temperature of 100 ° C to 200 ° C.
The method according to claim 1,

Wherein the adhesive comprises a thermoplastic resin or a thermosetting resin.
The method according to claim 1,

Wherein the adhesive has an adhesive strength of 200 mPa to 600 mPa.
The method according to claim 1,

Wherein the pouch exterior member includes a long side portion facing the long side region of the electrode assembly and a short side portion facing the short side region of the electrode assembly,

Wherein the inner folding portion faces the short side portion, and the adhesive is interposed between the inner folding portion and the short side portion.
8. The method of claim 7,

Wherein the pouch exterior member further comprises a curved surface portion connecting the long side portion and the short side portion,

Wherein the inner folding portion faces the curved portion, and the adhesive is interposed between the inner folding portion and the curved portion.
The method according to claim 1,

Wherein the height of the outer folding portion is smaller than the height of the inner folding portion.
The method according to claim 1,

Wherein an insulating tape is attached to the inner folding portion and the outer folding portion so that the insulating tape covers an end portion of the outer folding portion.