Patent Description:
In general, secondary batteries include nickelcadmium batteries, nickel-hydrogen batteries, lithium ion batteries, and lithium ion polymer batteries. Such a secondary battery is being applied to be used in small-sized products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, E-bikes, and the like as well as large-sized products requiring high power such as electric vehicles and hybrid vehicles, power storage devices for storing surplus power or renewable energy, and backup power storage devices.

In general, in order to manufacture the secondary battery, first, electrode active material slurry is applied to a positive electrode collector and a negative electrode collector to manufacture a positive electrode and a negative electrode. Then, the electrodes are stacked on both sides of a separator to form an electrode assembly. Also, the electrode assembly is accommodated in a battery case, and then the battery case is sealed after an electrolyte is injected therein.

Such a secondary battery is classified into a pouch type secondary battery and a can type secondary battery according to a material of a case accommodating the electrode assembly. In the pouch type secondary battery, an electrode assembly is accommodated in a pouch made of a flexible polymer material. Also, in the can type secondary battery, an electrode assembly is accommodated in a case made of a metal or plastic material.

A pouch, which is a case of the pouch type secondary battery, is manufactured by forming a cup part by performing press processing on a pouch film having flexibility. In addition, when the cup part is formed, an electrode assembly is accommodated in an accommodation space of the cup part, and then, a side of the cup part is sealed to manufacture a secondary battery.

In the press processing, drawing molding is performed by inserting a pouch film into a molding device such as a press equipment and applying a pressure to the pouch film by using a punch to draw the pouch film. The pouch film is provided as a plurality of layers, and a moisture barrier layer disposed in the pouch film is made of a metal. However, according to the related art, the metal of the moisture barrier layer has a large crystal grain size among aluminum alloys, and the moisture barrier layer has a thin thickness. Therefore, when the side is folded to reduce energy density relative to a volume, the side is not fixed and unfolded again at a predetermined angle. Accordingly, when the tape is separately attached to the side, there is a problem in that the overall thickness of the secondary battery increases due to a thickness of the tape itself. In addition, since an additional process of attaching the tape is required after the process of folding the side, there is a problem in that the number of processes increases, and manufacturing yield of the secondary battery is reduced.

An object of the present invention is to provide an apparatus and method for folding a side, in which the side and a cup part do not adhere to each other when the side of a secondary battery is folded, but the side increases in retention force to be maintained in a folded state while being in contact with the cup part.

The objects of the present invention are not limited to the aforementioned object, but other objects not described herein will be clearly understood by those skilled in the art from descriptions below.

An apparatus for folding a side extending outward from a cup part in a battery case of a pouch-type secondary battery according to the independent claim <NUM> for solving the above problems includes: a body having a plate shape, adjacent to the side, and disposed to be elongated in a longitudinal direction of the secondary battery, wherein the body includes: a heating part disposed at one side thereof to heat an inner portion disposed at a relatively inner side of the side; and a pressing part disposed at the other side thereof to press an outer portion disposed at a relatively outer side of the side, wherein, when the heating part heats the inner portion, the body rotates to allow the pressing part to press the outer portion.

In addition, the inner portion of the side may not be sealed, and the outer portion of the side may be sealed.

In addition, the side may not adhere to the cup part and be folded at the inner portion.

In addition, the side may be in contact with an outer wall of the cup part and be folded.

In addition, the side may include: a first folding part folded at a position that is relatively closer to an outer end; and a second folding part folded at a position that is relatively closer to the cup part.

In addition, the first folding part may be disposed at the outer portion, and the second folding part may be disposed at the inner portion.

In addition, the side may be folded at an angle of <NUM>° to <NUM>° with respect to the first folding part.

In addition, the side may be folded at an angle of <NUM>° to <NUM>° with respect to the second folding part.

The heating part heats the inner portion at a temperature of <NUM> to <NUM>.

The heating part heats the inner portion for a time of <NUM> second to <NUM> seconds.

In addition, the battery case may be manufactured by molding a pouch film, and the pouch film may include: a sealant layer made of a first polymer and formed at the innermost layer; a surface protection layer made of a second polymer and formed at the outermost layer; and a gas barrier layer made of a metal containing an AA80XX-based aluminum alloy and laminated between the surface protection layer and the sealant layer, wherein the gas barrier layer may have a thickness of <NUM> to <NUM>, and the sealant layer may have a thickness of <NUM> to <NUM>.

In addition, the heating part may include a heating coil, which receives power from the outside to generate heat, therein.

In addition, the heating part may include a tube in which a fluid flows.

A method for folding a side according to the independent claim <NUM> for solving the above problems includes: allowing a body having a plate shape to be disposed adjacent to side and to be elongated in a longitudinal direction of a secondary battery; allowing a heating part disposed at one side of the body to be in contact with an inner portion disposed at a relatively inner side of the side, thereby heating the inner portion; and allow the body to rotate so that a pressing part disposed at the other side of the body presses an outer portion disposed at a relatively outer side of the side.

In the heating of the inner portion, the heating part heats the inner portion at a temperature of <NUM> to <NUM>.

In the heating of the inner portion, the heating part heats the inner portion for a time of <NUM> second to <NUM> seconds.

An apparatus for folding a side, which folds a side extending outward from a cup part in a battery case of a pouch-type secondary battery, according to the independent claim <NUM> includes: a first side folding device configured to primarily fold the side; and a second side folding device configured to secondarily fold the side, wherein the first side folding device includes a first body having a circular shape, adjacent to the side, and disposed to be elongated in a longitudinal direction of the secondary battery, wherein the first body heats an inner portion disposed at a relatively inner side of the side and presses the inner portion in a direction in which the inner portion is folded, and the second side folding device includes a second body having a plate shape, adjacent to the side, and disposed to be elongated in the longitudinal direction of the secondary battery, wherein the second body comprises: a heating part disposed at one side thereof to heat the inner portion disposed at the relatively inner side of the side; and a pressing part disposed at the other side to press an outer portion disposed at a relatively outer side of the side, wherein, after the first side folding device heats and presses the inner portion by using the first body, the second body of the second side folding device moves in a direction closer to the cup part so that the heating part heats the inner portion, and the pressing part presses the outer portion. The heating part heats the inner portion at a temperature of <NUM> to <NUM> for a time of <NUM> second to <NUM> seconds.

The cup part includes a first cup part disposed at a lower side, and a second cup part disposed above the first cup part, and the first body of the first side folding device moves upward from a lower side that is a direction from the first cup part to the second cup part to heat and press the inner portion.

After the first side folding device heats and presses the inner portion, when the second body of the second side folding device moves in the direction closer to the cup part, the second body may linearly move in the direction closer to the cup part.

The linear movement of the second body may be linear movement moving along a virtual plane parallel to a plane formed by a bottom portion of the cup part.

A method for folding a side which extends outward from a cup part in a battery case of a pouch-type secondary battery, according to the independent claim <NUM> includes: a primary side folding process of primarily folding the side by using a first side folding device; and a secondary side folding process of secondarily folding the side by using a second side folding device, wherein the primary side folding process includes a process of heating an inner portion disposed at a relatively inner side of the side and pressing the inner portion in a direction, in which the inner portion is folded, by using a first body of the first side folding device comprising the first body having a circular shape, adjacent to the side, and disposed to be elongated in a longitudinal direction of the secondary battery, and the secondary side folding process performed after the primary side folding process includes a process of heating the inner portion through a heating part disposed at one side thereof and pressing an outer portion disposed at a relatively outer side of the side through a pressing part disposed at the other side thereof while moving a second body of the second side folding device, which includes the second body having a plate shape, adjacent to the side, and disposed to be elongated in the longitudinal direction of the secondary battery, in a direction closer to the cup part. The heating part heats the inner portion at a temperature of <NUM> to <NUM> for a time of <NUM> second to <NUM> seconds.

The cup part includes a first cup part disposed at a lower side, and a second cup part disposed above the first cup part, and in the primary side folding process, the first body of the first side folding device moves upward from a lower side that is a direction from the first cup part to the second cup part to heat and press the inner portion.

In the secondary side folding process, when the second body of the second side folding device moves in the direction closer to the cup part, the second body may linearly move in the direction closer to the cup part.

Other particularities of the embodiments are included in the detailed description and drawings.

According to the embodiments of the present invention, there are at least the following effects.

The heating part of the apparatus for folding the side may heat the inner portion of the side to soften the first polymer of the sealant layer, and then, the pressing part of the apparatus for folding the side may press the outer portion of the side to allow the side to be in completely contact with the outer wall of the cup part and prevent the side from being unfolded again without attaching a separate tape.

The effects of the prevent invention are not limited by the aforementioned description, and thus, more varied effects are involved in this specification.

Advantages and features of the present invention, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. The present invention may, however be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Further, the present invention is only defined by scopes of claims.

Unless terms used in the present invention are defined differently, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art. Also, unless defined clearly and apparently in the description, the terms as defined in a commonly used dictionary are not ideally or excessively construed as having formal meaning.

In the following description, the technical terms are used only for explaining a specific exemplary embodiment while not limiting the present invention. In this specification, the terms of a singular form may include plural forms unless specifically mentioned. The meaning of "includes (comprises)" and/or "including (comprising)" does not exclude other components besides a mentioned component.

<FIG> is an assembled view of a secondary battery <NUM> according to an embodiment of the present invention;
An electrode assembly <NUM> is formed by alternately stacking electrodes and separators. First, slurry in which an electrode active material, a binder, and a plasticizer are mixed with each other is applied to a positive electrode collector and a negative electrode collector to manufacture the electrodes such as a positive electrode and a negative electrode. Then, respective separators are stacked between the electrodes to form the electrode assembly <NUM>, the electrode assembly <NUM> is inserted into the battery case <NUM>, and an electrolyte is injected to seal the battery case <NUM>.

Specifically, the electrode assembly <NUM> includes two types of electrodes, such as the positive electrode and the negative electrode, and the separator interposed between the electrodes to insulate the electrodes from each other. The electrode assembly <NUM> may be a stack type, a jelly roll type, a stacked and folding type, or the like. Each of the two types of electrodes, i.e., the positive electrode and the negative electrode has a structure in which active material slurry is applied to the electrode collector having a metal foil or metal mesh shape. The slurry may be usually formed by agitating a granular active material, an auxiliary conductor, a binder, and a plasticizer with a solvent added. The solvent may be removed in the subsequent process.

As illustrated in <FIG>, the electrode assembly <NUM> includes electrode tabs <NUM>. The electrode tabs <NUM> are respectively connected to a positive electrode and a negative electrode of the electrode assembly <NUM> to protrude outward from the electrode assembly <NUM>, thereby providing a path, through which electrons are moved, between the inside and outside of the electrode assembly <NUM>. An electrode collector of the electrode assembly <NUM> is constituted by a portion coated with an electrode active material and a distal end, on which the electrode active material is not applied, i.e., a non-coating part. Also, each of an electrode tabs <NUM> may be formed by cutting the non-coating part or by connecting a separate conductive member to the non-coating part through ultrasonic welding. As illustrated in <FIG>, the electrode tabs <NUM> may protrude in each of different directions of the electrode assembly <NUM>, but is not limited thereto. For example, the electrode tabs may protrude in various directions, for example, protrude in parallel to each other from one side in the same direction.

In the electrode assembly <NUM>, an electrode lead <NUM> that supplies electricity to the outside of the secondary battery <NUM> is connected to the electrode tab <NUM> through spot welding. Also, a portion of the electrode lead <NUM> is surrounded by an insulating part <NUM>. The insulating part <NUM> may be disposed to be limited to a side <NUM>, at which a first case <NUM> and a second case <NUM> of the battery case <NUM> are thermally fused, so that the electrode lead <NUM> is bonded to the battery case <NUM>. Also, electricity generated from the electrode assembly <NUM> may be prevented from flowing to the battery case <NUM> through the electrode lead <NUM>, and the sealing of the battery case <NUM> may be maintained. Thus, the insulating part <NUM> may be made of a nonconductor having non-conductivity, which is not electrically conductive. In general, although an insulation tape which is easily attached to the electrode lead <NUM> and has a relatively thin thickness is mainly used as the insulating part <NUM>, the present invention is not limited thereto. For example, various members may be used as the insulating part <NUM> as long as the members are capable of insulating the electrode lead <NUM>.

One end of the electrode lead <NUM> is connected to the electrode tab <NUM>, and the other end of the electrode lead <NUM> protrudes to the outside of the battery case <NUM>. That is, the electrode lead <NUM> includes a cathode lead <NUM> having one end connected to a cathode tab <NUM> to extend in a direction in which the cathode tab <NUM> protrudes and an anode lead <NUM> having one end connected to an anode tab <NUM> to extend in a direction in which the anode tab <NUM> protrudes. On the other hand, as illustrated in <FIG>, all of the other ends of the positive electrode lead <NUM> and the negative electrode lead <NUM> protrude to the outside of the battery case <NUM>. As a result, electricity generated in the electrode assembly <NUM> may be supplied to the outside. Also, since each of the positive electrode tab <NUM> and the negative electrode tab <NUM> is formed to protrude in various directions, each of the positive electrode lead <NUM> and the negative electrode lead <NUM> may extend in various directions.

The positive electrode lead <NUM> and the negative electrode lead <NUM> may be made of materials different from each other. That is, the cathode lead <NUM> may be made of the same material as the cathode collector, i.e., an aluminum (Al) material, and the anode lead <NUM> may be made of the same material as the anode collector, i.e., a copper (Cu) material or a copper material coated with nickel (Ni). Also, a portion of the electrode lead <NUM>, which protrudes to the outside of the battery case <NUM>, may be provided as a terminal part and electrically connected to an external terminal.

The battery case <NUM> is a pouch made of a flexible material, which accommodates the electrode assembly <NUM> therein. Hereinafter, the case in which the battery case <NUM> is the pouch will be described. When a pouch film <NUM> having flexibility is drawing-molded by using a punch <NUM> or the like, a portion of the pouch film <NUM> is stretched to form a cup part <NUM> including a pocket-shaped accommodation space <NUM>, thereby manufacturing the battery case <NUM>.

The battery case <NUM> accommodates the electrode assembly <NUM> so that a portion of the electrode lead <NUM> is exposed and then is sealed. As illustrated in <FIG>, the battery case <NUM> includes the first case <NUM> and the second case <NUM>. The accommodation space <NUM> in which the cup part <NUM> is formed to accommodate the electrode assembly <NUM> may be provided in the second case <NUM>, and the second case <NUM> may cover an upper side of the accommodation space <NUM> so that the electrode assembly <NUM> is not separated to the outside of the battery case <NUM>. As illustrated in <FIG>, one side of the first case <NUM> and one side of the second case <NUM> may be connected to each other. However, the present invention is not limited thereto. For example, the first case <NUM> and the second case <NUM> may be separately manufactured to be separated from each other.

When the cup part <NUM> is molded in the pouch film <NUM>, only one cup part <NUM> may be formed in one pouch film <NUM>, but the present invention is not limited thereto. For example, two cup parts may be drawing-molded to be adjacent to each other in one pouch film <NUM>. Then, as illustrated in <FIG>, the cup parts <NUM> are formed in the first case <NUM> and the second case <NUM>, respectively. Here, each of the cup parts <NUM>, which are respectively formed in the first case <NUM> and the second case <NUM>, may have the same depth D, but is not limited thereto, and may have different depths D. After accommodating the electrode assembly <NUM> in the accommodation space <NUM> provided in the cup part <NUM> of the first case <NUM>, the battery case <NUM> may be folded with respect to a bridge <NUM> formed between the two cup parts <NUM> in the battery case <NUM> so that the two cup parts <NUM> face each other. Then, the cup part <NUM> of the second case <NUM> also accommodates the electrode assembly <NUM> from the upper side thereof. Accordingly, since the two cup parts <NUM> accommodate one electrode assembly <NUM>, the electrode assembly <NUM> having a thicker thickness may be accommodated when compared to a case in which one cup part <NUM> is provided. In addition, since the first case <NUM> and the second case <NUM> are integrally connected to each other by folding the battery case <NUM>, the number of sides <NUM> to be sealed when a sealing process is performed later may be reduced. Thus, a process rate may be improved, and the number of sealing processes may be reduced.

The battery case <NUM> may include the cup part <NUM>, in which the accommodation space <NUM> accommodating the electrode assembly <NUM> is provided, and a degassing part <NUM> formed at a side portion of the cup part <NUM> to discharge a gas generated in the cup part <NUM> through a degassing hole H. When the electrode assembly <NUM> is accommodated in the cup part <NUM> of the battery case <NUM>, and the electrolyte is injected, and then an activation process is performed, a gas is generated inside the battery case <NUM>, and thus, a degassing process for discharging the gas to the outside is performed.

When the electrode lead <NUM> is connected to the electrode tab <NUM> of the electrode assembly <NUM>, and the insulating part <NUM> is formed on a portion of the electrode lead <NUM>, the electrode assembly <NUM> is accommodated in the accommodation space <NUM> provided in the cup part <NUM> of the first case <NUM>, and the second case <NUM> covers the accommodation space from the upper side. Also, the electrolyte is injected into the accommodation space, and the side <NUM> extending to the outside of the cup part <NUM> of each of the first case <NUM> and the second case <NUM> is sealed. The electrolyte may move lithium ions generated by electrochemical reaction of the electrode during charging and discharging of the secondary battery <NUM>. The electrolyte may include a non-aqueous organic electrolyte that is a mixture of a lithium salt and a high-purity organic solvent or a polymer using a polymer electrolyte. Furthermore, the electrolyte may include a sulfide-based, oxide-based, or polymer-based solid electrolyte, and the solid electrolyte may have flexibility that is easily deformed by external force. The pouch type secondary battery <NUM> may be manufactured through the above-described method.

<FIG> is a cross-sectional view of a pouch film <NUM> according to an embodiment of the present invention;
The pouch that is the battery case <NUM> of the pouch type secondary battery <NUM> according to an embodiment of the present invention may be manufactured by drawing the pouch film <NUM>. That is, the pouch film <NUM> is drawn by using the punch <NUM> or the like to form the cup part <NUM>, thereby manufacturing the battery case <NUM>. According to an embodiment of the present invention, as illustrated in <FIG>, the pouch film <NUM> includes a sealant layer <NUM>, a moisture barrier layer <NUM>, a surface protection layer <NUM>, and a drawing assistance layer <NUM>.

The sealant layer <NUM> may be made of the first polymer and be formed at the innermost layer to be in direct contact with the electrode assembly <NUM>. Here, the innermost layer represents a layer disposed at the last when oriented in a direction opposite to the direction in which the electrode assembly <NUM> is disposed with respect to the moisture barrier layer <NUM>. The battery case <NUM> may be manufactured while a portion of the pouch film <NUM> is drawn to form the cup part <NUM> including the accommodation space <NUM> having the pocket shape when the pouch film <NUM> having the stacked structure as described above is drawing-molded by using the punch <NUM> or the like. Also, when the electrode assembly <NUM> is accommodated in the accommodation space <NUM>, the electrolyte is injected. Thereafter, when the first case <NUM> and the second case <NUM> are in contact with each other so as to face each other, and thermal compression is applied to the side <NUM>, the sealant layers <NUM> are bonded to each other to seal the pouch. Here, since the sealant layer <NUM> is in direct contact with the electrode assembly <NUM>, the sealant layer <NUM> has to have insulating properties. Also, since the sealant layer <NUM> is in contact with the electrolyte, the sealant layer <NUM> has to have corrosion resistance. Also, since the inside of the battery case <NUM> is completely sealed to prevent materials from moving between the inside and outside of the battery case <NUM>, high sealability has to be realized. That is, the side <NUM> in which the sealant layers <NUM> are bonded to each other should have superior thermal bonding strength. In general, the first polymer forming the sealant layer <NUM> may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, teflon, and glass fiber. Particularly, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) is used for the sealant layer <NUM>. Polypropylene (PP) is excellent in mechanical properties such as tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance and chemical properties such as corrosion resistance and thus is mainly used for manufacturing the sealant layer <NUM>. Furthermore, the sealant layer <NUM> may be made of a casted polypropylene, an acid modified polypropylene, or a polypropylene-butylene-ethylene terpolymer. Here, the acid-treated polypropylene may be maleic anhydride polypropylene (MAH PP). Also, the sealant layer <NUM> may have a single layer structure made of one material or a composite layer structure in which two or more materials are respectively formed as layers.

According to an embodiment of the present invention, the sealant layer <NUM> may have a thickness of <NUM> to <NUM>, and in particular, a thickness of <NUM> to <NUM>. If the sealant layer <NUM> has a thickness less than <NUM>, there is a problem that the sealant layer <NUM> is deteriorated in durability such as a case in which the inside is broken during the sealing. On the other hand, if the thickness of the sealant layer <NUM> is thicker than <NUM>, since the entire pouch is excessively thick, the energy density to the volume of the secondary battery <NUM> may be reduced.

The moisture barrier layer <NUM> is stacked between the surface protection layer <NUM> and the sealant layer <NUM> to secure mechanical strength of the pouch, block introduction and discharge of a gas or moisture outside the secondary battery <NUM>, and prevent the electrolyte from leaking. The moisture barrier layer <NUM> is made of a metal, and in particular, the moisture barrier layer <NUM> according to an embodiment of the present invention may be made of a metal including an AA88XX-based aluminum alloy. Aluminum may secure the mechanical strength having a predetermined level or more, but be light in weight. Thus, aluminum may secure complement and heat dissipation for electrochemical properties due to the electrode assembly <NUM> and the electrolyte.

In the related art, although the AA30XX-based aluminum alloys are frequently used, there is a problem that mechanical strength is low because an iron content is <NUM> wt% or less. Thus, the aluminum alloy according to an embodiment of the present invention may be an AA80XX-based aluminum alloy. A variety of materials may be included in the aluminum alloy. For example, one or more kinds of materials selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), and zinc (Zn).

In addition, according to an embodiment of the present invention, the moisture barrier layer <NUM> may have a thickness of <NUM> to <NUM>, in particular, <NUM> to <NUM>. According to the related art, the moisture barrier layer has a thickness less than <NUM> to deteriorate the moldability. Accordingly, when the pouch film <NUM> is drawing-molded, there is a limit to form an outer wall <NUM> (see <FIG>) of the cup part <NUM> so as to be similar to a vertical state when the cup part <NUM> (see <FIG>) is formed to have a deep depth D.

Conversely, if the moisture barrier layer has a thickness greater than about <NUM>, not only the manufacturing cost increases, but also the total thickness of the secondary battery is excessively thick to deteriorate the energy density relative to the volume of the secondary battery. If the thickness of the sealant layer is reduced to be thinner than <NUM> in order to reduce the total thickness of the secondary battery, sealing durability may be deteriorated.

Therefore, according to an embodiment of the present invention, since moldability of the moisture barrier layer <NUM> is improved, when the pouch film <NUM> is drawing-molded, the outer wall <NUM> of the cup part <NUM> may be formed to be similar to the vertical state while the depth D of the cup part <NUM> is formed deeply. Thus, since the accommodation space <NUM> increases in volume, the electrode assembly <NUM> accommodated in the accommodation space <NUM> may also increase in volume, and energy efficiency compared to the volume of the secondary battery <NUM> may also increase. In addition, the manufacturing costs may not increase significantly, the total thickness of the pouch may not increase significantly without reducing the thickness of the sealant layer <NUM>, and the sealing durability may not be deteriorated.

The surface protection layer <NUM> is made of the second polymer and formed at the outermost layer to protect the secondary battery <NUM> against external friction and collision and also electrically insulates the electrode assembly <NUM> from the outside. Here, the outermost layer represents a layer disposed at the last when oriented in a direction opposite to the direction in which the electrode assembly <NUM> is disposed with respect to the moisture barrier layer <NUM>. The second polymer forming the surface protection layer <NUM> may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, teflon, and glass fiber. Particularly, a polymer such as polyethylene terephthalate (PET) having abrasion resistance and heat resistance may be used mainly. Also, the surface protection layer <NUM> may have a single layer structure made of one material or a composite layer structure in which two or more materials are respectively formed as layers.

According to an embodiment of the present invention, the surface protection layer <NUM> may have a thickness of <NUM> to <NUM>, in particular, <NUM> to <NUM>. If the thickness of the surface protection layer <NUM> is less than <NUM>, there may be a problem that external insulation is deteriorated. On the other hand, if the thickness of the surface protection layer <NUM> is thicker than <NUM>, the entire pouch is thicker, and thus, the energy density to the volume of the secondary battery <NUM> may be reduced.

Although PET is inexpensive, has excellent durability, and has excellent electrical insulation, the PET has poor bonding force with respect to aluminum, which is frequently used for the moisture barrier layer <NUM>, and also, a behavior when the PET is drawn by applying stress may be different. Thus, when the surface protection layer <NUM> and the moisture barrier layer <NUM> are directly bonded to each other, the protection layer <NUM> and the moisture barrier layer <NUM> may be delaminated during the drawing molding. As a result, the moisture barrier layer <NUM> is not uniformly drawn to cause the deterioration in moldability.

According to an embodiment of the present invention, the battery case <NUM> may be made of a third polymer and further include the drawing assistance layer <NUM> that is stacked between the surface protection layer <NUM> and the moisture barrier layer <NUM>. The drawing assistance layer <NUM> may be stacked between the surface protection layer <NUM> and the moisture barrier layer <NUM> to prevent the surface protection layer <NUM> and the moisture barrier layer <NUM> from being delaminated when the surface protection layer <NUM> and the moisture barrier layer <NUM> are drawn. The third polymer forming the drawing assistance layer <NUM> may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, teflon, and glass fiber. Particularly, since a nylon resin easily adheres to polyethylene terephthalate (PET) of the surface protection layer <NUM>, and a behavior when being drawn is similar to that of an aluminum alloy of the moisture barrier layer <NUM>, the nylon resin may be mainly used. Also, the drawing assistance layer <NUM> may have a single layer structure made of one material or a composite layer structure in which two or more materials are respectively formed as layers.

According to the related art, the moisture barrier layer had a thickness of about <NUM> to about <NUM>, particularly <NUM>, and thus, the drawing assistance layer had a fairly thin thickness of about <NUM>. That is, a thickness ratio of the drawing assistance layer and the moisture barrier layer is <NUM>:<NUM>, and a thickness rate of the moisture barrier layer was considerably high. However, as described above, according to an embodiment of the present invention, since the moisture barrier layer <NUM> has a thickness of approximately <NUM> to approximately <NUM>, and in particular, a thickness of <NUM> to <NUM>, the moldability of the moisture barrier layer <NUM> is improved. Here, in order to also improve the moldability of the drawing assistance layer <NUM>, the drawing assistance layer <NUM> may have a thickness of <NUM> to <NUM>, and in particular, a thickness of <NUM> to <NUM>. If the drawing assistance layer <NUM> has a thickness less than <NUM>, the drawing assistance layer <NUM> may not conform to the improved moldability of the moisture barrier layer <NUM> and may be damaged during the drawing. Conversely, if the sealant layer <NUM> has a thickness greater than <NUM>, the total thickness of the pouch is thick to increase in volume of the secondary battery and deteriorate in energy density. Particularly, according to an embodiment of the present invention, a thickness ratio of the drawing assistance layer <NUM> and the moisture barrier layer <NUM> may be less than <NUM>:<NUM>. That is, the thickness ratio of the drawing assistance layer <NUM> may more increase when compared to the thickness ratio of the drawing assistance layer <NUM> according to the related art. However, when the thickness of the drawing assistance layer <NUM> is excessively thick, the total thickness of the pouch is thicker, and thus, the thickness ratio may be greater than <NUM>:<NUM> in order to prevent the total thickness of the pouch from be excessively thicker. That is, the thickness ratio may be <NUM>:<NUM> to <NUM>:<NUM>.

<FIG> is a schematic view illustrating a state in which the side <NUM> of the battery case <NUM> is sealed according to an embodiment of the present invention.

The electrode assembly <NUM> is accommodated in the cup part <NUM> formed by drawing-molding the pouch film <NUM>, and the battery case <NUM> is folded with respect to a bridge <NUM> so that the two cup parts <NUM> of the first case <NUM> and the second case <NUM> face each other. In addition, after sealing the side <NUM> and performing a degassing process through the degassing part <NUM>, the degassing part <NUM> is cut. As a result, as illustrated in <FIG>, a length of the degassing part <NUM> may be shortened, and a volume of the secondary battery <NUM> may be reduced.

In the side <NUM> remaining after cutting the degassing part <NUM> among the plurality of sides <NUM>, the electrode lead <NUM> is not formed to protrude. However, if the side <NUM> is left as it is after sealing, the overall volume of the secondary battery <NUM> increases. Accordingly, to reduce energy density relative to the volume, it is desirable to fold the side <NUM>.

The side <NUM> may include an outer portion <NUM> and an inner portion <NUM> as illustrated in <FIG>. The outer portion <NUM> is a portion that is disposed relatively outward from the side <NUM> and is sealed, and the inner portion <NUM> is an area that is disposed relatively inward from the side <NUM> and is not sealed.

Particularly, when the side <NUM> of the battery case <NUM> is sealed to form the outer portion <NUM>, the outer portion <NUM> may not be directly connected to the cup part <NUM>, but be spaced a predetermined distance from the cup part <NUM>. When sealing the side <NUM>, heat and pressure are applied to the side <NUM> using a separate sealing tool (not shown). However, if the side <NUM> is sealed while the sealing tool is in close contact with the cup part <NUM>, a sealant layer <NUM> disposed inside the side <NUM> is partially melted to leak toward the electrode assembly <NUM>, thereby contaminating the electrode assembly <NUM>. In addition, the heat of the sealing tool may be transferred to the electrode assembly <NUM> to damage the electrode assembly <NUM>. Therefore, it is preferable to seal the side <NUM> in a state in which the sealing tool is spaced apart from the cup part <NUM> to some extent. Then, a portion sealed by the sealing tool becomes the outer portion <NUM>, and a portion that is not sealed because the sealing tool is spaced apart from the cup part <NUM> becomes the inner portion <NUM>.

<FIG> is a schematic side view illustrating a state in which the side <NUM> is folded according to the related art, and <FIG> is a schematic top view illustrating a state in which the side <NUM> is folded according to the related art.

In the related art, when the side <NUM> is folded, there is a problem in that the side <NUM> is not fixed and is unfolded again at a predetermined angle. Specifically, as described above, the pouch film <NUM> is formed by stacking the sealant layer <NUM>, the moisture barrier layer <NUM>, the drawing assistance layer <NUM>, and the surface protection layer <NUM>. Among them, since the sealant layer <NUM> includes a first polymer, particularly polypropylene (PP), flexibility and elasticity are good. Therefore, when the side <NUM> is folded, restoring force to return to the original state is large. On the other hand, since the moisture barrier layer <NUM> is made of a metal, in particular, an aluminum alloy, after the side <NUM> is folded, a limit of elastic deformation is exceeded, and thus the retention force to maintain the folded state is large.

However, in the pouch film <NUM> according to the related art, the moisture barrier layer <NUM> has a thickness of about <NUM> to <NUM>, and the sealant layer <NUM> has a thickness of about <NUM> to <NUM>. That is, the thickness of the moisture barrier layer <NUM> is significantly thinner than the thickness of the sealant layer <NUM>. Therefore, the restoring force is greater than the retention force, and thus, the side <NUM> is not fixed and unfolded again at a predetermined angle. Then, there is a problem in that an unnecessary volume of the secondary battery <NUM> increases due to the side <NUM>.

To solve this problem, according to the related art, as illustrated in <FIG> and <FIG>, a tape <NUM> is separately attached to the side <NUM>. In particular, the tape <NUM> is attached together to the side <NUM> and the outer surface of the bottom <NUM> of the cup part <NUM> to fixing the side <NUM> to the cup part <NUM>, thereby preventing the side from being unfolded again. However, in this case, as illustrated in <FIG>, there is a problem in that the overall thickness of the secondary battery <NUM> increases due to the thickness of the tape <NUM> itself. In addition, as illustrated in <FIG>, there is a problem in that an outer appearance of the secondary battery <NUM> is not elegant, and also, merchantability is deteriorated.

According to an embodiment of the present invention, the thickness of the moisture barrier layer <NUM> may be about <NUM> to about <NUM>, particularly about <NUM> to about <NUM>, and the thickness of the sealant layer <NUM> may be about <NUM> to about <NUM>, particularly about <NUM> to <NUM> to about <NUM>. Therefore, since the thickness of the moisture barrier layer <NUM> increases when compared to the related art, the moldability of the moisture barrier layer <NUM> is improved, and the retention force of the side <NUM> increases, and thus, a phenomenon in which the side <NUM> is unfolded again after being folded may be reduced to some extent. However, since the thickness of the sealant layer <NUM> is not reduced, restoring force of the side <NUM> to return to its original state is also large to some extent. Therefore, even after the side <NUM> is folded, the side <NUM> may not be still in completely contact with the outer wall <NUM> of the cup part <NUM>, but may be unfolded again to some extent.

<FIG> is a schematic side view illustrating a state in which a heating part <NUM> of the apparatus <NUM> for folding the side <NUM> heats the inner portion <NUM> of the side <NUM> according to an embodiment of the present invention.

When only one cup part <NUM> is formed on the pouch film <NUM>, the depth D of the cup part <NUM> may be sufficiently deep, and thus, the side <NUM> may be folded only once. On the other hand, when the two cup parts <NUM> are formed on the pouch film <NUM>, the depth D of the cup part <NUM> may be shallower than when one cup part <NUM> is formed. This is because, when the pouch film <NUM> is molded, not only the cup part <NUM> is intensively drawn, but also the peripheral sides <NUM> of the cup part <NUM> are finely drawn as a whole. However, if the width of the side <NUM> is longer than the depth D of the cup part <NUM>, when the side <NUM> is folded only once, the outer end <NUM> of the side <NUM> may further protrude outward than the bottom part <NUM> of the cup part <NUM>.

Accordingly, if the two cup parts <NUM> are formed on the pouch film <NUM>, double side folding (DSF) method of folding the side <NUM> twice as illustrated in <FIG> may be used. Specifically, the side <NUM> may include a first folding part <NUM> and a second folding part <NUM>. The first folding part <NUM> is a portion folded at a position relatively closer to the outer end <NUM>, and the second folding part <NUM> is a portion folded at a position relatively closer to the cup part <NUM>. Accordingly, after the side <NUM> is first folded based on the first folding part <NUM>, the side <NUM> may be secondarily folded based on the second folding part <NUM>. In this case, the first folding part <NUM> may be disposed on the outer portion <NUM> at the side <NUM>, and the second folding part <NUM> may be disposed on the inner potion <NUM> at the side <NUM>. Thus, it is possible to prevent the outer end <NUM> of the side <NUM> from protruding further outward than the bottom part <NUM> of the cup part <NUM>.

The side <NUM> may be folded at an angle of <NUM>° to <NUM>°, in particular, an angle of <NUM>° with respect to the first folding part <NUM>. In addition, the side <NUM> is preferably folded in the second folding part <NUM> so that the side <NUM> is in completely contact with the outer wall <NUM> of the cup part <NUM>. However, as described above, since the restoring force of the sealant layer <NUM> is also large to some extent, even after the side <NUM> is folded, the side may not be still in completely contact with the outer wall <NUM> of the cup part <NUM> and then may be unfolded again to some extent.

According to an embodiment of the present invention, after the heating part <NUM> of the apparatus <NUM> for folding the side heats the inner portion <NUM> of the side <NUM> to soften a first polymer of the sealant layer <NUM>, the pressing part <NUM> of the apparatus <NUM> for folding the side may press the outer portion <NUM> of the side <NUM>. As a result, the side <NUM> may be in completely contact with the outer wall <NUM> of the cup part <NUM> to prevent the side from being unfolded again without attaching a separate tape.

For this, an apparatus <NUM> for folding a side, which folds a side <NUM> extending outward from a cup part <NUM> in a battery case <NUM> of a pouch-type secondary battery <NUM>, according to an embodiment of the present invention includes a body <NUM> having a plate shape, adjacent to the side <NUM>, and disposed to be elongated in a longitudinal direction of the secondary battery <NUM>, wherein the body <NUM> includes: a heating part <NUM> disposed at one side thereof to heat an inner portion <NUM> disposed at a relatively inner side of the side <NUM>; and a pressing part <NUM> disposed at the other side thereof to press an outer portion <NUM> disposed at a relatively outer side of the side <NUM>, and when the heating part <NUM> heats the inner portion <NUM>, the body <NUM> rotates to allow the pressing part <NUM> to press the outer portion <NUM>.

The apparatus <NUM> for folding the side may include the body <NUM> having a very thin plate shape. The body <NUM> may have a relatively narrow width and a relatively long length. And, as illustrated in <FIG>, the body <NUM> may be disposed adjacent to the side <NUM> of the secondary battery <NUM>, and in this case, the body <NUM> may be disposed to be elongated in the longitudinal direction of the secondary battery <NUM>.

The body <NUM> includes the heating part <NUM> disposed at one side thereof to heat the inner portion <NUM> and the pressing part <NUM> disposed at the other side thereof to press the outer portion <NUM>. When the body <NUM> is disposed adjacent to the side <NUM>, the heating part <NUM> of the body <NUM> may be disposed to be adjacent to the inner portion <NUM> of the side <NUM>. In addition, when the heating part <NUM> may be in contact with the inner portion <NUM> of the side <NUM> to apply heat, thereby softening a first polymer of a sealant layer <NUM> included in the side <NUM>. The heating part <NUM> may heat the inner portion <NUM> at a temperature of <NUM> to <NUM> for a time of <NUM> second to <NUM> seconds, preferably <NUM> seconds to <NUM> seconds. If the heating part <NUM> heats at a temperature lower than <NUM> or for a time shorter than <NUM> second, the first polymer of the sealant layer <NUM> may not be sufficiently softened. Also, if the heating part <NUM> is heated at a temperature higher than <NUM> or for a time longer than <NUM> seconds, the sealant layer <NUM> disposed inside the side <NUM> may be partially melted to leak toward the electrode assembly <NUM>. As a result, an electrode assembly <NUM> may be contaminated, and the heat of the heating part <NUM> may be transferred to the electrode assembly <NUM> to damage the electrode assembly <NUM>.

As described above, since a second folding part <NUM> is disposed on the inner portion <NUM>, and the side <NUM> is secondarily folded based on the second folding part <NUM>, the inner portion <NUM> may include a curved surface. On the other hand, as described above, since the body <NUM> has the plate shape, the heating part <NUM> may be formed to be flat to some extent. Accordingly, in order to allow the heating part <NUM> to be in easily contact the inner portion <NUM>, as illustrated in <FIG>, the body <NUM> may have an inclination about an axis in the longitudinal direction and be disposed to be adjacent to the side <NUM>. In addition, even if the heating part <NUM> is in contact with the inner portion <NUM> to heat the inner portion <NUM> of the side <NUM>, since a contact area is not large, the heating part <NUM> in the body <NUM> may be formed to be relatively narrowed compared to the pressing part <NUM>.

According to an embodiment of the present invention, the heating part <NUM> of the body <NUM> may include a heating coil (not shown) that receives power from the outside to generate heat. For this, a power supply part such as a battery and an external power source may be connected to the body <NUM>. In addition, according to another embodiment of the present invention, the heating part <NUM> of the body <NUM> may include a thin tube in which a high-temperature fluid flows. For this, an inlet/outlet tube (not shown) through which the fluid is introduced and discharged may be connected to the body <NUM>, and a separate pump (not shown) may be connected to the inlet/outlet tube. That is, if the heating part <NUM> generates heat, various methods may be used without being limited.

<FIG> is a schematic side view illustrating a state in which the pressing part <NUM> of the apparatus <NUM> for folding the side <NUM> presses the outer portion <NUM> of the side <NUM> according to an embodiment of the present invention, and <FIG> is a schematic side view illustrating a state in which the side <NUM> is folded according to an embodiment of the present invention.

After the heating part <NUM> heats the inner portion <NUM> of the side <NUM>, the body <NUM> rotates so that the pressing part <NUM> presses the outer portion <NUM> of the side <NUM>. Here, it is preferable that the pressing part <NUM> presses a position that is far away from the second folding part <NUM> of the side <NUM>. This is because the pressing part <NUM> easily presses the side <NUM> at small torque as the pressing position is farther from the second folding part <NUM>, which serves as a rotation center of the side <NUM>. For this, as illustrated in <FIG>, a width of the body <NUM> is preferably formed to be longer than a width of the side <NUM>.

When the heating part <NUM> heats the inner portion <NUM> of the side <NUM>, the first polymer of the sealant layer <NUM> is softened. Thereafter, when the pressing part <NUM> presses the outer portion <NUM> of the side <NUM>, the first polymer of the sealant layer <NUM> is deformed. Then, when a certain amount of time elapses in this state, the first polymer of the sealant layer <NUM> is cooled and hardened. Accordingly, the pressing part <NUM> may press the outer portion <NUM> for <NUM> seconds or more, preferably <NUM> second or more. If the pressing part <NUM> presses the outer portion <NUM> for a time shorter than <NUM> seconds, the first polymer of the sealant layer <NUM> may not be sufficiently hardened, and thus, the side <NUM> may be unfolded again.

The apparatus <NUM> for folding the side may further include a power part (not shown) for moving and rotating the body <NUM>. The power part may move the body <NUM> to be adjacent to the side <NUM>, move the heating part <NUM> to be in contact with the inner portion <NUM>, and rotate the pressing part <NUM> to press the outer portion <NUM>.

In this process, after the side <NUM> is folded toward the cup part <NUM> in the secondary battery <NUM>, the side <NUM> may not adhere to the cup part <NUM> while being maintained in the folded state and thus may not be unfolded. Here, the side <NUM> may be folded at an angle of <NUM>° to <NUM>°, preferably an angle of <NUM>° to <NUM>° with respect to the second folding part <NUM>. In addition, the side <NUM> may be folded at a position adjacent to the cup part <NUM> so that the side <NUM> is in contact with the outer wall <NUM> of the cup part <NUM>. Particularly, when the side <NUM> is folded, it is preferable that the inner portion <NUM> that is relatively closer to the cup part <NUM> is folded. Thus, the unnecessary volume of the secondary battery <NUM> may be further reduced. However, even in this case, the side <NUM> and the cup part <NUM> do not adhere to each other, and the retention force of the side <NUM> increases to maintain the folded state.

<FIG> is a schematic side view illustrating a state in which a first body of a first side folding device heats and presses the inner portion of the side according to another embodiment of the present invention. <FIG> is a schematic side view illustrating a state in which a second body of a second side folding device linearly moves in a direction closer to a cup part according to another embodiment of the present invention. <FIG> is a schematic side view illustrating a state in which a heating part of the second side folding device heats the inner portion of the side, and a pressing part presses an outer portion of the side according to another embodiment of the present invention.

Another embodiment of the present invention is different from the previously described embodiment in that a first side folding device <NUM> and a second side folding device <NUM> move linearly to perform an operation of folding the side <NUM>.

The contents that are duplicated with the foregoing embodiment will be omitted as much as possible, and Embodiment <NUM> will be described with a focus on the differences. That is, it is obvious that the contents that are not described in another embodiment may be regarded as the contents of the foregoing embodiment if necessary.

Referring to <FIG>, an apparatus for folding a side according to another embodiment of the present invention may be an apparatus for folding a side <NUM> extending outward from a cup part <NUM> in a battery case <NUM> of a pouch-type secondary battery and include a first side folding device <NUM> and a second side folding device <NUM>.

The first side folding device <NUM> may be a device for primarily folding the side <NUM> of the battery case <NUM>. In addition, the second side folding device <NUM> may be a device for secondarily folding the side <NUM> of the battery case <NUM>.

Referring to <FIG>, the first side folding device <NUM> may include a first body <NUM> having a circular cross-section and disposed to be adjacent and elongated to the side <NUM> in a longitudinal direction of the secondary battery. The first body <NUM> may heat an inner portion <NUM> disposed at a relatively inner side of the side <NUM> and press the inner portion <NUM> in a direction in which the inner portion <NUM> is folded.

A cup part <NUM> may include a first cup part <NUM>-<NUM> disposed at a lower side and a second cup part <NUM>-<NUM> disposed above the first cup part <NUM>-<NUM>. A first body <NUM> of the first side folding device <NUM> may move upward from the lower side that is a direction from the first cup part <NUM>-<NUM> to the second cup part <NUM>-<NUM> to heat and press the inner portion <NUM>. <FIG> illustrates a state in which the first body <NUM> moves from the lower side to an upper direction U so as to be in contact with the inner portion <NUM>, thereby heating the inner portion <NUM> and also pressing the inner portion <NUM> in the folding direction.

Referring to <FIG> and <FIG>, the second side folding device <NUM> may include a second body <NUM> having a plate shape and disposed to be adjacent and elongated to the side <NUM> in a longitudinal direction of the secondary battery. Here, the second body <NUM> may include a heating part <NUM> and a pressing part <NUM>. The heating part <NUM> may be disposed at one side of the second body <NUM> and may be configured to heat the inner portion <NUM> disposed at a relatively inner side of the side <NUM>. In addition, the pressing part <NUM> may be disposed at the other side of the second body <NUM> and may be configured to press the outer portion <NUM> disposed at a relatively outer side of the side <NUM>.

In the apparatus for folding the side according to another embodiment of the present invention, after the first side folding device <NUM> heats and presses the inner portion <NUM> using the first body <NUM> (see <FIG>), the second body <NUM> of the second side folding device <NUM> may move in a direction closer to the cup part <NUM> (see <FIG>), and the heating part <NUM> may heat the inner portion <NUM>, and also, the pressing part <NUM> may press the outer portion <NUM> to perform the folding of the side <NUM> (see <FIG>).

In the apparatus for folding the side according to another embodiment of the present invention, after the first side folding device <NUM> heats and presses the inner portion <NUM>, when the second body <NUM> of the second side folding device <NUM> moves in the direction closer to the cup part <NUM>, the second body <NUM> may linearly move in the direction closer to the cup part <NUM>. That is, the second body <NUM> of the second side folding device <NUM> may not rotate but move linearly and may be closer to the cup part <NUM> to perform the operation of folding the side <NUM>.

Here, the linear movement of the second body <NUM> may be linear movement moving along a virtual plane parallel to a plane formed by a bottom portion <NUM> of the cup part <NUM>. That is, the second body <NUM> may perform the folding operation while not moving in a downward direction toward the first cup part <NUM>-<NUM> or in an upward direction toward the second cup part <NUM>-<NUM>, but moving linearly in only a direction F that is closer to the side <NUM>.

A method for folding the side <NUM> using the apparatus for folding the side according to another embodiment of the present invention is as follows.

Referring to <FIG>, a method for folding the side <NUM> according to another embodiment of the present invention may be a method for folding a side <NUM> extending outward from a cup part <NUM> in a battery case <NUM> of a pouch-type secondary battery and include a process of primarily folding the side <NUM> and a process of secondarily folding the side <NUM>. The process of primarily folding the side <NUM> may be a process of primarily folding the side <NUM> using a first side folding device <NUM>. The process of secondarily folding the side <NUM> may be a process of secondarily folding the side <NUM> using a second side folding device <NUM>.

Referring to <FIG>, the process of primarily folding side <NUM> may be a process of heating an inner portion <NUM> disposed at a relatively inner side of the side <NUM> and pressing the inner portion <NUM> in a direction, in which the inner portion <NUM> is folded, by using a first body <NUM> of the first side folding device <NUM> including the first body <NUM> having a circular cross-section and disposed to be adjacent and elongated to the side <NUM> in a longitudinal direction of the secondary battery.

Referring to <FIG> and <FIG>, the process of secondarily folding side <NUM> may be a process, in which a second body <NUM> of the second side folding device <NUM> including the second body <NUM> having a plate shape and disposed to be adjacent and elongated to the side <NUM> in the longitudinal direction of the secondary battery moves in a direction closer to the cup part <NUM> (see <FIG>) to heat the inner portion <NUM> through a heating part disposed at one side thereof and press an outer portion <NUM>, which is disposed at a relatively outer side of the side <NUM>, through a pressing part <NUM> disposed at the other side thereof (see <FIG>). Here, the process of secondarily folding the side <NUM> may be a process that is performed after the process of primarily folding the side <NUM>.

In the method for folding the side <NUM> according to another embodiment of the present invention, the cup part <NUM> may include a first cup part <NUM>-<NUM> disposed at a lower side and a second cup part <NUM>-<NUM> disposed above the first cup part <NUM>-<NUM>. In the process of primarily the side <NUM>, the first body <NUM> of the first side folding device <NUM> may move upward from the lower side that is a direction from the first cup part <NUM>-<NUM> to the second cup part <NUM>-<NUM> to heat and press the inner portion <NUM>.

Also, in the process of secondarily folding the side <NUM>, when the second body <NUM> of the second side folding device <NUM> moves in the direction closer to the cup part <NUM>, the second body <NUM> may move linearly in the direction F closer to the cup part <NUM>. Also, in this case, the linear movement of the second body <NUM> may be linear movement moving along a virtual plane parallel to a plane formed by a bottom portion <NUM> of the cup part <NUM>.

As described above, the apparatus and method for folding the side according to another embodiment of the present invention may have an advantage of being able to perform the folding operation while the first body <NUM> of the first side folding device <NUM> and the second body <NUM> of the second side folding device <NUM> move linearly without rotating.

In addition, the first body <NUM> may perform the operation of heating the inner portion <NUM> of the side <NUM>, and then, the second body <NUM> may also perform the operation of heating the inner portion <NUM>. Thus, it may have an advantage of being able to relatively reduce a minimum required time for the heating operation.

Those with ordinary skill in the technical field of the present invention pertains will be understood that the present invention can be carried out in other specific forms without changing the technical idea or essential features. Therefore, the above-disclosed embodiments are to be considered illustrative and not restrictive. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein. Various modifications made within the meaning of an equivalent of the claims of the invention and within the claims are to be regarded to be in the scope of the present invention.

Claim 1:
An apparatus (<NUM>) for folding a side (<NUM>), which folds a side (<NUM>) extending outward from a cup part (<NUM>) in a battery case (<NUM>) of a pouch-type secondary battery (<NUM>), the apparatus (<NUM>) comprising:
a body (<NUM>) having a plate shape, adjacent to the side (<NUM>) of the battery case (<NUM>), and disposed to be elongated in a longitudinal direction of the secondary battery (<NUM>),
wherein the body (<NUM>) comprises:
a heating part (<NUM>) disposed at one side thereof to heat an inner portion (<NUM>) disposed at a relatively inner side of the side (<NUM>) of the battery case (<NUM>); and
a pressing part (<NUM>) disposed at the other side thereof to press an outer portion (<NUM>) disposed at a relatively outer side of the side (<NUM>) of the battery case (<NUM>),
wherein, when the heating part (<NUM>) heats the inner portion (<NUM>), the body (<NUM>) rotates to allow the pressing part (<NUM>) to press the outer portion (<NUM>),
wherein the heating part (<NUM>) heats the inner portion (<NUM>) at a temperature of <NUM> to <NUM> for a time of <NUM> second to <NUM> seconds.