Pouch-type battery cell

Abstract

A pouch-type battery cell according to an embodiment of the present invention may include an electrode assembly accommodated between a first case and a second case. The pouch-type battery cell may include a cup portion formed in at least one of the first case or the second case and accommodating the electrode assembly, a folding portion where an edge of the first case wraps around an edge of the second case to form a discharge flow path between an edge of the first case and an edge of the second case, a sealing portion formed in the folding portion, and a vent portion that connects the cup portion to the discharge flow path when the pressure resistance of the cup portion increases.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0048247 filed on April 12, 2023 and Korean Patent Application No. 10-2023-0067111 filed on May 24, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a pouch-type battery cell. [Background technology]

[0003] Recently, secondary batteries have been attracting attention as a power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are being proposed as a way to solve the air pollution caused by existing gasoline and diesel vehicles that use fossil fuels.

[0004] Small mobile devices generally use one or two to three secondary batteries, whereas medium to large devices such as electric vehicles use a battery module in which multiple secondary batteries are electrically connected or a battery pack in which multiple battery modules are electrically connected to each other due to the need for high output and large capacity.

[0005] Among the currently commercially available secondary batteries, lithium secondary batteries are one of the most popular. Lithium secondary batteries can be classified into can-type, prismatic-type, and pouch-type batteries depending on the type of exterior material. Among these, pouch-type secondary batteries are widely used in medium- to large-sized battery modules due to their high energy density and ease of stacking.

[0006] Meanwhile, as demand for high-energy secondary battery modules installed in vehicles increases, customer needs for battery stability are gradually increasing. That is, if a secondary battery has a high energy density, stability risks (e.g., risk of battery fire or explosion) may occur.

[0007] In general, a pouch-type battery cell has a structure in which an electrode assembly is housed in a pouch-type battery case, and a sealing portion is formed on the edge of the battery case.

[0008] If a battery cell exceeds its critical temperature due to abnormal heat generation, the temperature and pressure resistance rise rapidly, which can lead to an explosion. This can cause thermal propagation (TP) in other surrounding battery cells. Therefore, to prevent or sufficiently slow this heat propagation, it is necessary to vent the gas generated in the battery cell due to abnormal heat generation in a specific direction in advance. Summary of the Invention [Problem to be solved by the invention]

[0009] One problem to be solved by the present invention is to provide a pouch-type battery cell configured to release gas in a predetermined direction when the withstand pressure of a cup portion containing an electrode assembly increases. [Means for solving the problem]

[0010] A pouch-type battery cell according to an embodiment of the present invention may include an electrode assembly accommodated between a first case and a second case. The pouch-type battery cell may include: a cup portion formed in at least one of the first case or the second case and accommodating the electrode assembly; a folding portion where the edge of the first case wraps around the edge of the second case to form a discharge flow path between the edge of the first case and the edge of the second case; a sealing portion formed in the folding portion; and a vent portion that is unsealed or is sealed weaker than the sealing portion so that the cup portion and the discharge flow path communicate when the pressure resistance of the cup portion increases.

[0011] The sealing portion and the venting portion may be located between the cup portion and the discharge channel.

[0012] The folding portion may include a first facing portion facing one side of the edge of the second case, a second facing portion facing the other side of the edge of the second case, and a connecting portion connecting the first facing portion and the second facing portion and being bent or flexible with a predetermined gap from an end of the edge of the second case. The discharge channel may be formed within the connecting portion.

[0013] The thickness of the connecting portion in a direction parallel to the thickness of the edge portion of the second case may be greater than the sum of the thickness of the first facing portion, the thickness of the edge portion of the second case, and the thickness of the second facing portion.

[0014] A width of the discharge passage in a direction parallel to the thickness of the edge portion of the second case may be greater than the thickness of the edge portion of the second case.

[0015] The connecting portion may include a curved surface formed convexly on an outer side.

[0016] The sealing portion may be formed by sealing the first and second facing portions with the edge portion of the second case.

[0017] The venting portion may be formed by unsealing or weakly sealing the first facing portion and the edge portion of the second case to each other.

[0018] The discharge passage may extend in a direction of the entire length or width of the cup portion and have at least one end open.

[0019] A plurality of the venting portions may be provided along the peripheries of the first case and the second case.

[0020] The cup may include a first folding portion extending along the entire length of the cup and a second folding portion extending along the entire width of the cup. The venting portions may include a first venting portion located on an outer side of a long side of the cup, the first venting portion connecting the cup to a discharge channel in the first folding portion when the pressure resistance of the cup increases, and a second venting portion located on an outer side of a short side of the cup, the second venting portion connecting the cup to a discharge channel in the second folding portion when the pressure resistance of the cup increases.

[0021] A pouch-type battery cell according to an embodiment of the present invention may include an electrode assembly accommodated between a first case and a second case. The pouch-type battery cell may include: a cup portion formed in at least one of the first case or the second case and accommodating the electrode assembly; a folding portion where an edge of the first case wraps around an edge of the second case so as to form an exhaust flow path between the edge of the first case and the edge of the second case; a sealing portion formed in the folding portion; and a gas exhaust member disposed between the cup portion and the exhaust flow path and made of a gas-permeable material.

[0022] The gas discharge member may include a moisture absorbing material.

[0023] An inner end of the gas discharge member may be exposed to the inside of the cup portion.

[0024] An outer end of the gas discharge member may be exposed to the inside of the discharge passage.

[0025] The outer end of the gas discharge member may protrude further than the end of the edge of the second case.

[0026] The folding portion may include a first facing portion facing one side of the edge of the second case, a second facing portion facing the other side of the edge of the second case, and a connecting portion connecting the first facing portion and the second facing portion and being bent or flexible with a predetermined gap from an end of the edge of the second case. The discharge channel may be formed within the connecting portion.

[0027] The gas discharge member may be located between the first facing portion and the edge portion of the second case.

[0028] A plurality of the gas discharge members may be provided along the peripheries of the first case and the second case. [Effects of the Invention]

[0029] Therefore, when the pressure resistance of the cup portion accommodating the electrode assembly increases, the gas inside the cup portion can be discharged through the vent portion and the discharge passage in the folding portion in that order, thereby discharging the gas in a predetermined direction, thereby preventing the pouch-type battery cell from exploding and preventing thermal propagation (TP) from occurring in other surrounding battery cells due to the explosion.

[0030] Furthermore, the discharge flow path can be simply and easily realized using only the folded portion without the need for a separate device or additional sealing process.

[0031] Another advantage is that it is easy to appropriately design the flow rate at which gas is discharged by adjusting the length, number, and position of the venting portions.

[0032] Furthermore, when the pressure resistance of the cup portion housing the electrode assembly increases, the gas inside the cup portion can be discharged by passing through the gas discharge member and the discharge flow path in the folded portion in that order. This allows gas to be discharged without physically opening the cup portion, which has the advantage of maintaining the pressure resistance of the cup portion at an appropriate level and enabling continuous use of the pouch-type battery cell.

[0033] In addition, the present invention can include other effects that can be easily predicted by a person skilled in the art from the configuration of the preferred embodiment of the present invention. [Brief explanation of the drawings]

[0034] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited solely to the matters shown in such drawings.

[0035] [Figure 1] 1 is a perspective view illustrating a case and an electrode assembly of a pouch-type battery cell according to a first embodiment of the present invention; [Figure 2] FIG. 1 is a plan view of a pouch-type battery cell according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a partial cross-sectional view taken along line AA' in FIG. [Figure 4] FIG. 3 is a partial cross-sectional view taken along line BB' in FIG. [Figure 5] FIG. 5 is a diagram illustrating a modification of the coupling portion shown in FIGS. 3 and 4. [Figure 6] FIG. 10 is a plan view of a pouch-type battery cell according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a partial cross-sectional view taken along the line CC' in FIG. [Figure 8] FIG. 10 is a plan view of a pouch-type battery cell according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a plan view of a pouch-type battery cell according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a partial cross-sectional view taken along line DD' in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand the present invention. However, the present invention may be embodied in various different forms and should not be construed as being limited to the following embodiments.

[0037] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related known technologies that may obscure the gist of the present invention will be omitted. In this specification, when referring to components in each drawing, the same or similar reference numerals will be used throughout the specification to refer to the same or similar components.

[0038] FIG. 1 is a perspective view illustrating a case and an electrode assembly of a pouch-type battery cell according to a first embodiment of the present invention, FIG. 2 is a plan view of the pouch-type battery cell according to the first embodiment of the present invention, FIG. 3 is a partial cross-sectional view taken along line A-A' in FIG. 2, and FIG. 4 is a partial cross-sectional view taken along line B-B' in FIG. 2.

[0039] The pouch-type battery cell 10 according to the first embodiment may include a pair of cases 100 and an electrode assembly 200. More specifically, the pouch-type battery cell 10 may be manufactured by housing the electrode assembly 200 between a first case 100A and a second case 100B.

[0040] The first case 100A and the second case 100B can be sealed together with the electrode assembly 200 housed therein together with an electrolyte to form a pouch-type battery cell 10.

[0041] The electrode assembly 200 may include a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes to insulate them. The type of electrode assembly 200 is not limited. For example, the electrode assembly 200 may be a stack-type electrode assembly in which positive electrodes and negative electrodes are alternately stacked with a separator sandwiched between them. For another example, the electrode assembly 200 may be a jelly-roll-type electrode assembly in which sheet-type positive electrodes and negative electrodes are wound together with a separator sandwiched between them.

[0042] The combination of the first case 100A and the second case 100B provides a storage space capable of accommodating the electrode assembly 200, and may have an overall pouch shape.

[0043] One side of the first case 100A and one side of the second case 100B may be connected to each other, and the connected portion may form the folding region 103. That is, the pair of cases 100 may be connected together by the folding region 103. However, as another example, the first case 100A and the second case 100B may be provided as separate components that are subsequently sealed together.

[0044] Each case 100 can include a first resin layer forming the innermost layer, a second resin layer forming the outermost layer, and a metal layer positioned between the first and second resin layers. That is, each case 100 can be manufactured by molding a laminate film including the first resin layer, the second resin layer, and the metal layer.

[0045] The first resin layer, which forms the innermost layer, may be in direct contact with or adjacent to the electrode assembly 200 and the electrolyte. Therefore, the first resin layer may be formed of a material having high insulating properties and high corrosion resistance. For example, the first resin layer may include polypropylene (PP). However, the first resin layer is not limited thereto, and those skilled in the art may select the material of the first resin layer as appropriate.

[0046] The second resin layer, which forms the outermost layer, protects the pouch-type battery cell 10 from external friction and impact and electrically insulates the electrode assembly 200 from external objects. For example, the second resin layer may include a polyethylene terephthalate (PET) material. However, the second resin layer is not limited to this, and those skilled in the art can select the material for the second resin layer as appropriate.

[0047] Furthermore, at least one of the first resin layer and the second resin layer may be provided in a structure including two or more layers in order to improve formability and adhesiveness.

[0048] The metal layer ensures the mechanical strength of the case 100, blocks the ingress and egress of external gases or moisture, and prevents electrolyte leakage. The metal layer may be made of aluminum (Al) or stainless steel (STS). However, the metal layer is not limited thereto, and those skilled in the art may select the appropriate material for the metal layer.

[0049] Meanwhile, the pouch-type battery cell 10 may include a cup portion 110 formed in at least one of the first case 100A and the second case 100B, and configured to accommodate the electrode assembly 200 therein.

[0050] The cup portion 110 can be formed by drawing a laminate film, which is the base material of the case 100, and recessing it to a predetermined depth.

[0051] 1, a cup portion 110 may be provided in each of the first case 100A and the second case 100B. For example, the electrode assembly 200 may be accommodated in an accommodating space defined by the pair of cup portions 110. However, the present invention is not limited thereto, and the cup portion 110 may be provided in only one of the first case 100A and the second case 100B. In other words, the case not including the cup portion 110 may be flat.

[0052] The first case 100A and the second case 100B may include a rim 120 located on the periphery of the cup portion 110. The rim 120 may also be referred to as a terrace portion. The rims 120 of the first case 100A and the second case 100B may be positioned to abut against each other and may be sealed together, thereby sealing the electrode assembly 200 within the first case 100A and the second case 100B.

[0053] When the first case 100A and the second case 100B are integrally provided with the folding region 103, the folding region 103 can be folded so that the edges 120 of the first case 100A and the second case 100B abut against each other. In this case, the abutting edges 120 can form three sides of the pouch-type battery cell 10, and the folding region 103 can form the remaining side. Therefore, sealing portions 150, which will be described later, can be formed on the three sides of the pouch-type battery cell 10.

[0054] The pouch-type battery cell 10 may include a folding portion 130 in which the edge 120 of the first case 100A wraps around the edge 120 of the second case 100B so that a discharge flow path 140 is formed between the edge 120 of the first case 100A and the edge 120 of the second case 100B.

[0055] The edge 120 of the first case 100A can be folded, flexed, or bent to form the folded portion 130. More specifically, to form the folded portion 130, the edge 120 of the first case 100A can be folded over an end of the edge 120 of the second case 100B at a predetermined distance.

[0056] The fold portion 130 can extend the entire length or width of the cup portion 110 .

[0057] At least one, and preferably a plurality of, folding portions 130 may be provided. For example, as shown in Fig. 2, folding portions 130 may be formed on three of the four sides of the pouch-type battery cell 10 excluding the folding region 103. In this case, the plurality of folding portions 130 may include a first folding portion 130A extending along the entire length of the cup portion 110 and a second folding portion 130B extending along the entire width of the cup portion 110.

[0058] However, the present invention is not limited to this, and it goes without saying that the folding portion 130 may be formed only on a part of the third side.

[0059] To form the folding portion 130, the edge 120 of the first case 100A may be formed wider than the edge 120 of the second case 100B. More specifically, the edge 120 of the first case 100A may be formed longer in the overall length and / or width direction than the edge 120 of the second case 100B.

[0060] 1, a first line L1 and a second line L2 are shown on the edge 120 of the first case 100A to exemplarily indicate lines corresponding to the ends of the edge 120 of the second case 100B. The first line L1 may be parallel to the overall length of the pouch-type battery cell 10, and the second line L2 may be parallel to the overall width of the pouch-type battery cell 10.

[0061] The corner portion where the first line L1 and the second line L2 overlap at the edge 120 of the first case 100A can be double-folded, or alternatively, the corner portion can be cut to an appropriate shape by a person skilled in the art.

[0062] More specifically, referring to Figure 3 or Figure 4, the folding portion 130 may include a first facing portion 131 facing one side of the edge portion 120 of the second case 100B, a second facing portion 132 facing the other side of the edge portion 120 of the second case 100B, and a connecting portion 133 connecting the first facing portion 131 and the second facing portion 132.

[0063] The first facing portion 131 can come into contact with one surface of the edge portion 120 of the second case 100B. The second facing portion 132 can come into contact with the other surface of the edge portion 120 of the second case 100B.

[0064] The connecting portion 133 may be folded, bent, or flexed at a predetermined distance from the end of the rim portion 120 of the second case 100B. With this configuration, an exhaust passage 140 may be formed within the connecting portion 133. When the pressure resistance of the cup portion 110 increases, gas generated within the cup portion may be exhausted to the outside of the pouch-type battery cell 10 by passing through a vent portion 160 (described below) and the exhaust passage 140 in that order.

[0065] The cross-sectional shape of the discharge channel 140 may be defined by the shape of the connecting portion 133. For example, the connecting portion 133 may include a curved surface formed in a convex shape on the outside. In this case, a portion of the cross section of the discharge channel 140 may be substantially rounded.

[0066] The first facing portion 131 and the second facing portion 132 can overlap each other in the thickness direction of the edge portion 120 of the second case 100B. The first facing portion 131 and the second facing portion 132 can be joined to the edge portion 120 of the second case 100B by a sealing portion 150, which will be described later.

[0067] A thickness t2 of the connecting portion 133 in a direction parallel to the thickness of the edge portion 120 of the second case 100B (the vertical direction with reference to FIG. 3) may be greater than the sum t1 of the thickness of the first facing portion 131, the thickness of the edge portion 120 of the second case 100B, and the thickness of the second facing portion 132. That is, the thickness t2 of the connecting portion 133 may be greater than the thickness of the sealing portion 150. In other words, the connecting portion 133 may be formed to protrude further in the thickness direction than the first facing portion 131 and the second facing portion 132.

[0068] The width W of the discharge flow path 140 in a direction parallel to the thickness of the edge portion 120 of the second case 100B (the vertical direction with reference to FIG. 4) may be greater than the thickness t0 of the edge portion 120 of the second case 100B.

[0069] With this configuration, the cross-sectional area of ​​the exhaust flow path 140 can be made sufficiently large, and the gas can be smoothly discharged through the exhaust flow path 140.

[0070] The exhaust channels 140 may extend along the entire length or width of the cup portion 110 and may be open at least at one end, preferably both ends. The open ends of the exhaust channels 140 may act as exhaust ports through which gas is discharged. The arrows in FIG. 2 schematically show gas being discharged from the ends of the exhaust channels 140 in each folded portion 130. This eliminates the need to form a separate exhaust port in the folded portion 130.

[0071] As shown in FIG. 2, the sealing portion 150 may be formed on the folded portion 130 and may be formed to extend along the folded portion 130 .

[0072] The sealing portion 150 may be formed by various methods, for example, by heat sealing, laser welding, ultrasonic welding, or resistance welding.

[0073] More specifically, the sealing portion 150 may be located between the cup portion 110 and the discharge channel 140. Therefore, the sealing portion 150 may separate the internal space of the cup portion 110 from the discharge channel 140.

[0074] 3, the sealing portion 150 may be formed by sealing the first facing portion 131 and the second facing portion 132 to the edge portion 120 of the second case 100B. More specifically, the sealing portion 150 may include a first sealing portion 151 that seals the edge portion 120 of the second case 100B to the first facing portion 131, and a second sealing portion 152 that seals the edge portion 120 of the second case 100B to the second facing portion 132. In other words, the sealing portion 150 may be doubly sealed to the folding portion 130, thereby providing high sealing strength.

[0075] The pouch-type battery cell 10 may include a venting portion 160 located between the cup portion 110 and the exhaust channel 140. The venting portion 160 may be formed by sealing a portion of the folded portion 130 weaker than the sealing portion 150 so that when the pressure resistance of the cup portion 110 increases, the weak seal breaks and the cup portion 110 and the exhaust channel 140 communicate with each other. Alternatively, the venting portion 160 may not be sealed. Therefore, the cup portion 110 can selectively communicate with the exhaust channel 140 in any case.

[0076] More specifically, the venting portion 160 may be formed by loosely sealing the first facing portion 131 and the edge portion 120 of the second case 100B to each other or by leaving a specific area unsealed. That is, a portion of the first sealing portion 151 may be left unsealed or loosely sealed, and defined as the venting portion 160.

[0077] The venting portion 160 may overlap the second sealing portion 152 in the thickness direction of the edge portion 120 of the second case 100B.

[0078] When the first facing portion 131 and the edge portion 120 of the second case 100B are weakly sealed to each other to form the venting portion 160, the sealing strength of the venting portion 160 may be lower than the sealing strength of each of the first sealing portion 151 and the second sealing portion 152.

[0079] 4, when the first opposing portion 131 and the edge portion 120 of the second case 100B are not sealed to each other to form the venting portion 160, an increase in the pressure resistance of the cup portion 110 may cause the first opposing portion 131 and the edge portion 120 of the second case 100B to separate, creating a gap g. As a result, gas within the cup portion 110 can flow to the exhaust passage 140 through the gap g.

[0080] Alternatively, if the first opposing portion 131 and the edge portion 120 of the second case 100B are weakly sealed to each other to form the venting portion 160, an increase in the pressure resistance of the cup portion 110 may cause the first opposing portion 131 and the edge portion 120 of the second case 100B to separate, destroying the weak seal and creating a gap g. As a result, gas within the cup portion 110 can flow to the exhaust passage 140 through the gap g.

[0081] At least one, preferably a plurality of venting portions 160 may be provided along the periphery of the first case 100A and the second case 100B.

[0082] At least one venting portion 160 may be formed in each folding portion 130. For example, if the plurality of folding portions 130 includes a first folding portion 130A and a second folding portion 130B, the plurality of venting portions 160 may include a first venting portion 160A located along the length of the edge portion 120 and a second venting portion 160B located along the width of the edge portion 120.

[0083] When the pressure resistance of the cup portion 110 increases, the first venting portion 160A can connect the discharge flow path 140 in the first folding portion 130A to the cup portion 110, and the second venting portion 160B can connect the discharge flow path 140 in the second folding portion 130B to the cup portion 110.

[0084] However, it goes without saying that a single folded portion 130 may have multiple vents 160 formed therein.

[0085] The pouch-type battery cell 10 has the advantage that it is easy to design an appropriate flow rate for discharging gas from the cup portion 110 by adjusting the length, number, and position of the venting portion 160.

[0086] FIG. 5 is a diagram illustrating a modification of the coupling portion shown in FIGS.

[0087] The connection portion 133′ according to the modified example may form a discharge channel 140′. The width of the discharge channel 140′ in a direction parallel to the thickness of the edge portion 120 of the second case 100B (the vertical direction in FIG. 5) may be the same as or similar to the thickness t0 of the edge portion 120 of the second case 100B.

[0088] In order to ensure that the cross-sectional area of ​​the discharge flow passage 140' is sufficiently wide, the width W' of the discharge flow passage 140' in a direction parallel to the width of the edge portion 120 of the second case 100B (the horizontal direction with reference to FIG. 5) may be greater than the thickness t0 of the edge portion 120 of the second case 100B. Preferably, the width W' of the discharge flow passage 140' may be at least twice the thickness t0 of the edge portion 120 of the second case 100B.

[0089] The connecting portion 133' may form a polygonal discharge channel 140' that does not include any curved surfaces. However, this is not limited to this, and it goes without saying that the connecting portion 133' may include a curved surface, as in the first embodiment.

[0090] FIG. 6 is a plan view of a pouch-type battery cell according to a second embodiment of the present invention, and FIG. 7 is a partial cross-sectional view taken along CC' in FIG.

[0091] In the pouch-type battery cell 10a according to the second embodiment, a folding portion 130 may be formed on some of the three sides other than the folding region 103, and a sub-folding portion 170 may be formed on the remaining sides.

[0092] The sub-folding portion 170 may be provided such that the edge 120 of the first case 100A is folded to enclose the edge 120 of the second case 100B, so that no discharge passage is formed. That is, the sub-folding portion 170 may be folded, bent, or bent at a position that contacts or is adjacent to the end of the edge 120 of the second case 100B.

[0093] Similar to the folding unit 130, the sub-folding unit 170 may include a first facing unit 171 facing one side of the edge 120 of the second case 100B, a second facing unit 172 facing the other side of the edge 120 of the second case 100B, and a connecting unit 173 connecting the first facing unit 171 and the second facing unit 172. The connecting unit 173 may be folded, bent, or flexed while in contact with or adjacent to the end of the edge 120 of the second case 100B.

[0094] A sealing portion 150 may be formed on the sub-folding portion 170. The sealing portion 150 formed on the sub-folding portion 170 may be formed by sealing a first facing portion 171 and a second facing portion 172 to the edge portion 120 of the second case 100B. More specifically, the sealing portion 150 may include a first sealing portion 151 that seals the edge portion 120 of the second case 100B to the first facing portion 171, and a second sealing portion 152 that seals the edge portion 120 of the second case 100B to the second facing portion 172. That is, the sealing portion 150 may be doubly sealed to the sub-folding portion 170, thereby providing higher sealing strength.

[0095] The sub-folding portion 170 can be formed more compactly than the folding portion 130. Therefore, by forming the sub-folding portion 170 instead of the folding portion 130 in areas where the formation of the discharge flow path 140 is not necessary, the energy density of the pouch-type battery cell 10a can be improved.

[0096] FIG. 8 is a plan view of a pouch-type battery cell according to a third embodiment of the present invention.

[0097] The pouch-shaped battery cell 10b according to the third embodiment can be manufactured by sealing a first case 100A and a second case 100B, which are separate components and not connected together. The edges 120 of the first case 100A and the second case 100B can abut against each other and then be sealed together to form the four sides of the pouch-shaped battery cell 10b. Therefore, sealing portions 150 can be formed on the four sides of the pouch-shaped battery cell 10b.

[0098] The folding portion 130 may be formed on at least one of the four sides of the pouch-type battery cell 10. As an example, as shown in Fig. 8, the folding portions 130 may be provided in a pair, arranged parallel to each other and on opposite sides of the cup portion 110. As another example, the folding portion 130 may be formed on each of the four sides of the pouch-type battery cell 10. As described above, at least one venting portion 160 may be formed in each folding portion 130.

[0099] FIG. 9 is a plan view of a pouch-type battery cell according to a fourth embodiment of the present invention, and FIG. 10 is a partial cross-sectional view taken along line DD' in FIG.

[0100] Below, we will omit content that overlaps with the above content and focus on the differences.

[0101] The pouch-type battery cell 10c according to the fourth embodiment may include a gas discharge member 180 provided in the folding portion 130 and disposed between the cup portion 110 and the discharge passage 140. The gas discharge member 180 can be used in place of the venting portion 160 of the first embodiment described above.

[0102] The gas discharge member 180 can be positioned between the cup portion 110 and the discharge passage 140. The gas discharge member 180 can be positioned between the first facing portion 131 of the folded portion 130 and the edge portion 120 of the second case 100B.

[0103] The gas discharge member 180 can overlap the second sealing portion 152 in the thickness direction of the edge portion 120 of the second case 100B.

[0104] The gas exhaust member 180 may be made of a gas-permeable material. Therefore, when the pressure resistance of the cup part 110 increases, the gas inside the cup part 110 can be exhausted to the exhaust passage 140 through the gas exhaust member 180.

[0105] An inner end of the gas discharge member 180 may be disposed inside the cup portion 110. An outer end of the gas discharge member 180 may be disposed inside the discharge passage 140. The width of the gas discharge member 180 may be wider than the width of the sealing portion 150, particularly the second sealing portion 152. Therefore, gas generated in the cup portion 110 may be smoothly discharged to the discharge passage 140 through the gas discharge member 180.

[0106] Preferably, the outer end of the gas exhaust member 180 can protrude further than the end of the edge 120 of the second case 100B. This allows the gas that has permeated the gas exhaust member 180 to be exhausted not only in the width direction of the gas exhaust member 180 (the horizontal direction in FIG. 10) but also in the surface direction (the vertical direction in FIG. 10). That is, the gas can be smoothly exhausted to the exhaust flow path 140.

[0107] The length L of the gas discharge member 180 can be adjusted as needed depending on the gas discharge amount required for the pouch-type battery cell 10c and the gas permeability of the gas discharge member 180. The length of the gas discharge member 180 may refer to the direction parallel to the length of the sealing portion 150.

[0108] The gas discharge member 180 may be made of a material having a higher melting point than the first resin layer (e.g., a PP layer) that forms the innermost layer of the case 100. In addition, the gas discharge member 180 may be made of a material that does not react with the electrolyte.

[0109] For example, the gas discharge member 180 may include a binder including at least one of an olefin-based resin, an acrylic-based resin, and a fluorine-based resin. For example, the olefin-based resin may be polypropylene (PP), polyethylene (PE), or polyvinyldifluoride (PVDF). The fluorine-based resin may be polytetrafluoroethylene (PTFE) or polyvinylidenefluoride.

[0110] The gas discharge member allows gas to be discharged without physical opening, which has the advantage of maintaining the pressure resistance of the cup portion 110 at an appropriate level and allowing the pouch-type battery cell 10c to be used continuously.

[0111] The gas discharge member 180 may further include a moisture absorbing material to increase gas permeability while minimizing moisture penetration. That is, the gas discharge member 180 may include a getter material. For example, the moisture absorbing material may be calcium oxide (CaO), barium oxide (BaO), lithium chloride (LiCl), silica (SiO2), calcium (Ca), barium (Ba), etc., but is not limited thereto. Any material that reacts with water (H2O) may be used.

[0112] Moisture outside the pouch-type battery cell 10c reacts with the moisture-absorbing material of the gas discharge member 180 and is removed, so that moisture can be prevented from penetrating into the cup portion 110.

[0113] The gas discharge member 180 may be in the form of a film, but is not limited thereto, and may be formed by coating at least one of the first facing portion 131 and the edge portion 120 of the second case 100B with a resin containing the binder and / or moisture absorbing material by a known coating method.

[0114] The joining force of the gas discharge member 180 to the first facing portion 131 and / or the edge portion 120 of the second case 100B may be smaller than the joining force of the sealing portion 150, particularly the second sealing portion 152.

[0115] As the pressure resistance of the cup portion 110 increases, the interface between the first facing portion 131 and / or the edge portion 120 of the second case 100B and the gas discharge member 180 can gradually separate, thereby increasing the amount of gas permeating through the gas discharge member 180.

[0116] Furthermore, if the pressure resistance of the cup portion 110 becomes very high, the interface between the first facing portion 131 and / or the edge portion 120 of the second case 100B and the gas discharge member 180 can be completely separated, creating a passage for gas discharge similar to the gap g in Figure 4. This allows gas to be discharged quickly, improving the safety of the pouch-type battery cell 10c.

[0117] Referring to FIG. 9, at least one, preferably a plurality of gas discharge members 180 may be provided along the peripheries of the first case 100A and the second case 100B.

[0118] Each folded portion 130 may be provided with at least one gas discharge member 180. For example, if the plurality of folded portions 130 includes a first folded portion 130A and a second folded portion 130B, the plurality of gas discharge members 180 may include a first gas discharge member 180A positioned along the length of the edge portion 120 and a second gas discharge member 180B positioned along the width of the edge portion 120.

[0119] When the pressure resistance of the cup portion 110 increases, gas that passes through the first gas discharge member 180A can be discharged to the discharge flow path 140 in the first folded portion 130A, and gas that passes through the second gas discharge member 180B can be discharged to the discharge flow path 140 in the second folded portion 130B.

[0120] However, it goes without saying that a plurality of gas discharge members 180 can be formed on a single folded portion 130. On the other hand, it goes without saying that the gas discharge member 180 can be used in place of the venting portion 160 of the second and third embodiments described above.

[0121] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains without departing from the essential characteristics of the present invention.

[0122] Therefore, the embodiments disclosed in the present invention are intended to illustrate, not limit, the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0123] The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0124] 10 Pouch-type battery cells 100 cases 110 Cup section 120 Edge 130 Folding section 131 First Meeting Area 132 Second facing section 133 Connecting part 140 Discharge flow path 150 sealing part 151 First sealing section 152 Second sealing section 160 Venting section 180 Gas exhaust member 200 electrode assembly

Claims

1. A pouch-type battery cell in which an electrode assembly is housed between a first case and a second case, a cup portion formed in at least one of the first case and the second case and configured to accommodate the electrode assembly; a folding portion in which the edge of the first case wraps around the edge of the second case so that a discharge flow path is formed between the edge of the first case and the edge of the second case; a sealing portion formed on the folding portion; The pouch-type battery cell includes a venting portion that connects the cup portion to the discharge flow path when the pressure resistance of the cup portion increases.

2. The pouch-type battery cell according to claim 1 , wherein the sealing portion and the venting portion are located between the cup portion and the discharge channel.

3. The folding portion is a first facing portion facing one surface of the edge portion of the second case; a second facing portion opposite the first facing portion and facing the other surface of the edge portion of the second case; a connecting portion that connects the first facing portion and the second facing portion and is bent or flexible at a predetermined interval from an end of the edge portion of the second case, The pouch-type battery cell according to claim 1 , wherein the discharge channel is at least partially formed by the connecting portion.

4. 4. The pouch-type battery cell according to claim 3, wherein a thickness of the connecting portion in a direction parallel to a thickness of the edge portion of the second case is greater than a sum of a thickness of the first facing portion, a thickness of the edge portion of the second case, and a thickness of the second facing portion.

5. The pouch-type battery cell according to claim 3 , wherein a width of the discharge flow path in a direction parallel to a thickness of the edge portion of the second case is greater than a thickness of the edge portion of the second case.

6. The pouch-type battery cell according to claim 3 , wherein the connecting portion includes a curved surface formed in a convex shape on an outer side.

7. The sealing portion is a first sealing portion formed by sealing the first facing portion to the edge portion of the second case; The pouch-type battery cell according to claim 3 , wherein the second facing portion includes a second sealing portion sealed to the edge portion of the second case.

8. The venting section is The pouch-type battery cell according to claim 3 , wherein the first facing portion and the edge portion of the second case are formed unsealed or weakly sealed to each other.

9. The discharge flow path is The pouch-shaped battery cell according to claim 1 , wherein the cup portion extends in a full length or width direction and at least one end is open.

10. The pouch-type battery cell according to claim 1 , wherein the venting portion is provided in a plurality along the peripheries of the first case and the second case.

11. The folding portion and the venting portion are provided in plural, The plurality of folding portions include: a first folded portion extending in the overall length direction of the cup portion; a second folded portion extending in the width direction of the cup portion, The plurality of venting portions are a first venting portion located in the first folding portion; 2. The pouch-type battery cell according to claim 1, further comprising a second vent located in the second folded portion.

12. A pouch-type battery cell in which an electrode assembly is housed between a first case and a second case, a cup portion formed in at least one of the first case and the second case and configured to accommodate the electrode assembly; a folding portion in which the edge of the first case wraps around the edge of the second case so that a discharge flow path is formed between the edge of the first case and the edge of the second case; a sealing portion formed on the folding portion; a gas discharge member disposed between the cup portion and the discharge flow path and formed of a gas-permeable material;

13. The pouch-type battery cell of claim 12 , wherein the gas-permeable material includes a moisture-absorbing material.

14. The pouch-type battery cell according to claim 12 , wherein at least a portion of the inner end of the gas discharge member is located inside the cup portion.

15. The pouch-type battery cell according to claim 12 , wherein at least a portion of the outer end of the gas discharge member is located inside the discharge flow path.

16. The pouch-type battery cell according to claim 12 , wherein an outer end of the gas discharge member protrudes further than an end of the rim of the second case.

17. The folding portion is a first facing portion facing one surface of the edge portion of the second case; a second facing portion facing the other surface of the edge portion of the second case; a connecting portion that connects the first facing portion and the second facing portion and is bent or flexible at a predetermined interval from an end of the edge portion of the second case, The pouch-type battery cell according to claim 12 , wherein the discharge channel is at least partially formed by the connecting portion.

18. The pouch-type battery cell according to claim 17 , wherein the gas discharge member is located between the first facing portion and the edge portion of the second case.

19. The pouch-type battery cell according to claim 12 , wherein a plurality of the gas discharge members are provided along the peripheries of the first case and the second case.

20. the folding portion includes a sub-folding portion, The pouch-type battery cell according to claim 1 , wherein the connecting portion of the sub-folded portion contacts or is adjacent to an end of the edge portion of the second case.

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