Pouch-type secondary battery

Abstract

The present invention relates to a pouch-type secondary battery, comprising: a first cup portion indented in a predetermined first direction to form a first internal space; a first pouch having a first peripheral portion extending from the first cup portion in a predetermined horizontal direction perpendicular to the first direction and surrounding at least a portion of the first cup portion; a second cup portion disposed opposite the first pouch and indented in a direction opposite to the first direction to form a second internal space for accommodating an electrode assembly together with the first internal space; and a second pouch having a second peripheral portion extending from the second cup portion in the horizontal direction to surround at least a portion of the second cup portion and coupled to the first peripheral portion, wherein the second internal space may include an overlapping space overlapping the first internal space when projected in the first direction, and an additional space extending in the horizontal direction within the overlapping space but not overlapping the first internal space.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0000188, filed on January 2, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

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

[0003] Generally, a secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be recharged, and is widely used in electronic devices such as mobile phones, laptops, and camcorders, as well as electric vehicles, etc. In particular, lithium secondary batteries have a larger capacity and higher energy density than nickel-cadmium batteries or nickel-metal hydride batteries, and therefore their use is rapidly increasing.

[0004] Depending on the shape of the battery case, secondary batteries can be classified into cylindrical or prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is housed in a pouch-type case made of a laminate sheet.

[0005] FIG. 1 is a diagram showing an example of a pouch-type secondary battery. The pouch-type secondary battery 1 (pouch-type cell) includes an electrode assembly 2 formed by alternately stacking electrodes and separators, and a pouch-type exterior material 20 that houses the electrode assembly 2. Electrode tabs 15 may be connected to the electrodes of the electrode assembly 2. The electrode tabs 15 may be welded to each other in predetermined areas and then connected to an electrode lead 17 by welding. The exterior material 20 includes a housing portion 21 for housing the electrode assembly 2. The housing portion 21 of the exterior material 20 may be formed into one or two indented portions. FIG. 1 illustrates an example of the housing portion 21 formed into two indented portions. A sealing portion 23 (terrace) is formed around the periphery of the housing portion 21 by sealing.

[0006] Meanwhile, gas may be generated inside a pouch-type secondary battery under high temperature conditions. The generation of gas can increase the internal pressure of the secondary battery. When the internal pressure increases, it may be necessary to delay venting to ensure the safety of the secondary battery. To delay venting, it may be possible to consider increasing the space inside the secondary battery for accommodating the gas. However, this may be undesirable because it can increase the size of the secondary battery, thereby reducing the volumetric energy density of the secondary battery. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a pouch-type secondary battery that can secure additional space inside the secondary battery for accommodating gas due to delay in venting caused by gas generation in the secondary battery during use.

[0008] Another object of the present invention is to provide a pouch-type secondary battery that can secure additional space inside the secondary battery without reducing the volumetric energy density. [Means for solving the problem]

[0009] In one example, a pouch-type secondary battery includes a first cup portion indented in a predetermined first direction to form a first internal space; a first pouch having a first peripheral edge portion extending from the first cup portion in a predetermined horizontal direction perpendicular to the first direction and surrounding at least a portion of the first cup portion; a second cup portion disposed opposite the first pouch and indented in a direction opposite to the first direction to form a second internal space for accommodating an electrode assembly together with the first internal space; and a second pouch having a second peripheral edge portion extending from the second cup portion in the horizontal direction to surround at least a portion of the second cup portion and coupled to the first peripheral edge, wherein the second internal space may include an overlapping space overlapping the first internal space when projected in the first direction, and an additional space extending in the horizontal direction within the overlapping space but not overlapping the first internal space.

[0010] In another example, the additional space of the second internal space may be a space in which the electrode assembly is not disposed.

[0011] In yet another example, the additional space of the second internal space may be configured to accommodate gas so as to delay the start time of discharging the gas generated from inside the first pouch and the second pouch to the outside of the first pouch and the second pouch.

[0012] In yet another example, the horizontal length of the first peripheral portion may be determined based on the size of the first cup-shaped portion.

[0013] In yet another example, the first peripheral portion may include a non-overlapping portion that is positioned to correspond to the additional space of the second internal space and does not overlap the second peripheral portion when projected in the opposite direction to the first direction, and an overlapping portion that extends horizontally from the non-overlapping portion and overlaps the second peripheral portion.

[0014] In yet another example, the overlapping portion of the first peripheral edge portion and the second peripheral edge portion may be folded toward the first cup portion.

[0015] In yet another example, the overlapping portion of the first peripheral portion and the second peripheral portion may be bent toward the first cup portion so that the non-overlapping portion is not exposed outside the horizontal direction when projected in the opposite direction to the first direction.

[0016] In yet another example, the horizontal length of the non-overlapping portion may be a length that allows the overlapping portion of the first peripheral portion and the second peripheral portion to contact the first cup portion by bending.

[0017] In yet another example, the overlapping portion of the first peripheral portion and the second peripheral portion may be folded toward the first cup portion along a first folding line that is spaced a first distance from the outer end of the horizontal side of the first peripheral portion toward the first cup portion and parallel to the outer end of the first peripheral portion, and may be folded toward the first cup portion along a second folding line that is spaced a second distance from the first folding line toward the first cup portion and parallel to the first folding line.

[0018] In yet another example, the pouch-type secondary battery may further include a fixing tape attached to both the outer surface of the first cup portion and the second peripheral portion so as to pull the second peripheral portion toward the first cup portion and prevent the overlapping portion of the first peripheral portion and the second peripheral portion from opening in a direction away from the first cup portion.

[0019] In yet another example, a pouch-type secondary battery includes: a first cup portion indented in a predetermined first direction to form a first internal space; a first pouch having a first peripheral edge extending from the first cup portion and surrounding at least a portion of the first cup portion; a second cup portion disposed opposite the first pouch and indented in a direction opposite to the first direction to form a second internal space for accommodating an electrode assembly together with the first internal space; and a second pouch having a second peripheral edge extending from the second cup portion and surrounding at least a portion of the second cup portion and coupled to the first peripheral edge, wherein the second internal space is formed in a shape asymmetrical with the first internal space, and may include an additional space, in which the electrode assembly is not disposed, for accommodating gas generated from inside the first pouch and the second pouch, as a space provided by the asymmetric shape. [Effects of the Invention]

[0020] According to the present invention, the second internal space may be formed in a shape that is asymmetrical with the first internal space, thereby providing additional space for accommodating gas in the second internal space, thereby delaying the time at which venting begins.

[0021] Furthermore, according to the present invention, the additional space is provided by utilizing a portion of the space occupied by the secondary battery due to the peripheral portion of the conventional secondary battery, so that the additional space can be provided without reducing the volumetric energy density. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram showing an example of a pouch-type secondary battery. [Figure 2] 1 is a perspective view showing a pouch-type secondary battery according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing a cross section taken along line AA in FIG. 2. [Figure 4] 1 is a diagram for explaining a comparison between a conventional secondary battery and the secondary battery of Example 1. FIG. [Figure 5] FIG. 10 is a perspective view showing a pouch-type secondary battery according to a second embodiment of the present invention. [Figure 6] 6 is a perspective view showing the secondary battery of FIG. 5 before the peripheral edge portion is folded. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line CC in FIG. 6. [Figure 8] FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 9] 10 is a diagram for explaining a comparison between a conventional secondary battery and a secondary battery according to a second embodiment. FIG. [Figure 10] FIG. 6 is a perspective view showing a modified example of the secondary battery of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] 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 preferred embodiments of 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.

[0024] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or of related known technologies that may obscure the gist of the present invention will be omitted, and when adding reference numbers to components in each drawing in this specification, the same or similar reference numbers will be used for the same or similar components throughout the specification.

[0025] Furthermore, the terms and words used in this specification and claims should not be interpreted in a way that is limited to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that the inventor himself / herself can appropriately define the concept of a term in order to explain the invention in the best possible way.

[0026] Example 1 Fig. 2 is a perspective view showing a pouch-type secondary battery 100 according to a first embodiment of the present invention, and Fig. 3 is a cross-sectional view showing a cross section taken along line AA in Fig. 2. As shown in Fig. 2 and Fig. 3, the pouch-type secondary battery 100 according to this embodiment may include a first pouch 110 and a second pouch 120. For reference, the contents related to the first embodiment may be similarly applied to the following embodiments, unless they are mutually contradictory.

[0027] The pouch-type secondary battery 100 may include an electrode assembly 130 (see the electrode assembly designated by reference numeral 2 in FIG. 1) housed in the first and second pouches 110 and 120. The electrode assembly 130 may be formed by alternately stacking electrodes and separators. The electrodes may include a positive electrode and a negative electrode. The electrode assembly 130 may include electrode tabs (see FIG. 1) connected to the electrodes. The electrode tabs may be provided separately or as part of current collectors constituting the electrodes. The electrode tabs may be welded to each other at predetermined regions and then electrically connected to electrode leads (see FIG. 1).

[0028] Pouch-type secondary battery 100 may include a first pouch 110. First pouch 110 may include a first cup portion 111 that is indented in a predetermined first direction (D1, e.g., vertically upward) to form a first internal space 112, as shown in FIG. 3 . First pouch 110 may include a first peripheral edge portion 113 that extends from first cup portion 111 and surrounds at least a portion of first cup portion 111. First peripheral edge portion 113 may extend in a predetermined horizontal direction (D3; the direction opposite to D3 is also considered a horizontal direction) that is perpendicular to the first direction (D1). This may also be the case for second peripheral edge portion 123, which will be described later.

[0029] The pouch-type secondary battery 100 may include a second pouch 120. The second pouch 120 may be disposed opposite the first pouch 110 and may include a second cup portion 121 that is recessed in a direction (D2, e.g., vertically downward) opposite to the first direction (D1) to form a second internal space 122. The first and second internal spaces 112, 122 may together form a space for accommodating the electrode assembly 130. The second pouch 120 may include a second peripheral portion 123 that extends from the second cup portion 121 and surrounds at least a portion of the second cup portion 121.

[0030] The first and second pouches 110 and 120 may be prepared separately and then coupled to each other while facing each other, as shown in Figures 2 and 3. In this case, the first and second peripheral portions 113 and 123 may entirely surround the first and second pouches 110 and 120, respectively, as shown in Figure 2. The first and second peripheral portions 113 and 123 may be coupled to each other by heat sealing or the like to form a sealing portion.

[0031] The first and second pouches may be joined together by folding them to face each other as shown in Fig. 1. In this case, the first and second peripheral portions may partially surround the first and second pouches 110 and 120, respectively, excluding the folded portions. In this case, the first and second peripheral portions may be joined together to be sealed by heat sealing or the like to form a sealing portion.

[0032] The first and second pouches 110, 120 may be made of a laminate sheet including a metal layer such as aluminum, a first resin layer disposed on the inner surface of the metal layer, and a second resin layer disposed on the outer surface of the metal layer. The first resin layer may be a layer formed of polypropylene (PP). The first resin layer is required to have high insulating properties and corrosion resistance, and may be formed of another resin that meets these requirements. The second resin layer may be a layer formed of polyethylene terephthalate (PET). The second resin layer is required to protect the secondary battery while electrically insulating it, and may be formed of another resin that meets these requirements.

[0033] Meanwhile, the second internal space 122 of the second pouch 120 may be formed in a shape that is asymmetrical with the first internal space 112 of the first pouch 110, as shown in Fig. 3. For example, the second internal space 122 may include an overlapping space 122a that overlaps the first internal space 112 when projected in the first direction (D1), and additional spaces 122b (which may be formed at both the left and right ends of Fig. 3) that extend from the overlapping space 122a in the horizontal direction (D3) and do not overlap the first internal space 112. The second internal space 122 may be formed in a shape that is asymmetrical with the first internal space 112 due to the additional spaces 122b.

[0034] In the case of the secondary battery of this embodiment, the first peripheral portion 113 may include a non-overlapping portion 113a and an overlapping portion 113b due to the additional space 122b. The non-overlapping portion 113a may be a portion that is located to correspond to the additional space 122b of the second internal space 122 when projected in the opposite direction (D2) of the first direction (D1) and does not overlap with the second peripheral portion 123. The overlapping portion 113b may be a portion that extends from the non-overlapping portion 113a in the horizontal direction (D3) and overlaps with the second peripheral portion 123.

[0035] The secondary battery of this embodiment can delay the onset of venting due to the additional space 122b. This will be described below. Gas may be generated from within the first and second pouches 110 and 120. For example, gas may be generated during high-temperature storage of the secondary battery. The generation of gas can increase the internal pressure of the secondary battery. If the internal pressure increases, it may be necessary to delay venting (discharging gas from the inside of the secondary battery to the outside of the secondary battery) to ensure the safety of the secondary battery. In the secondary battery of this embodiment, the second internal space 122 is formed in an asymmetrical shape with the first internal space 112, so that an additional space 122b may be formed within the second internal space 122. Since gas can be accommodated in this additional space 122b, the onset of venting can be delayed compared to conventional secondary batteries that do not have the additional space 122b. This can improve the reliability of the secondary battery during high-temperature storage.

[0036] The additional space 122b of the second internal space 122 is a space that accommodates gas to delay venting, and may be a space in which the electrode assembly 130 is not disposed. To accommodate an asymmetrically shaped electrode assembly, the first and second internal spaces 112, 122 may be formed asymmetrically. For example, if the remaining lower portion of the electrode assembly 130 is larger than the upper portion, the second internal space may be formed larger than the first internal space to accommodate the electrode assembly. However, in this case, since the lower portion of the electrode assembly is entirely disposed in the second internal space, there may not be sufficient space in the second internal space to accommodate the gas.

[0037] As described above, the additional space 122b of the second internal space 122 may be provided to accommodate gas so as to delay the start time of discharging gas generated from the inside of the first and second pouches 110 and 120 to the outside of the first and second pouches 110 and 120, i.e., the start time of venting. However, in a secondary battery having an asymmetric internal space to accommodate the asymmetric electrode assembly described above, it appears that there is no extra space provided to accommodate gas.

[0038] The secondary battery of this embodiment can be provided with the aforementioned additional space 122b without reducing the volumetric energy density. This will be described above with reference to Fig. 4. Fig. 4 is a diagram for explaining the comparison between a conventional secondary battery and the secondary battery of Example 1.

[0039] To provide extra space for accommodating gas, it may be possible to increase the size of the pouch while maintaining the size of the electrode assembly. However, this would increase the size of the secondary battery, which would reduce the volumetric energy density of the secondary battery. However, compared to a conventional secondary battery (upper drawing of FIG. 4), the secondary battery of Example 1 (lower drawing of FIG. 4) provides additional space 122b by utilizing a portion of the space occupied by the secondary battery (i.e., space where other secondary batteries cannot be placed) due to the periphery of the conventional secondary battery. This allows the additional space 122b to be provided while maintaining the volumetric energy density of the conventional secondary battery, i.e., without reducing the volumetric energy density.

[0040] For example, in the case of the secondary battery of this embodiment, the length of first peripheral portion 113 in the horizontal direction (D3) may be determined regardless of additional space 122b provided in second pouch 120. When first and second internal spaces are symmetrically arranged, if the length of first peripheral portion 113 can be determined to be a predetermined L, the length of first peripheral portion 113 can be maintained at the same L as shown in FIG. 4 even when first and second internal spaces 112, 122 are asymmetrically arranged. This allows the secondary battery of this embodiment to maintain the volumetric energy density of a conventional secondary battery without additional space 122b. The length of first peripheral portion 113 in the horizontal direction (D3) may be determined based on, for example, the size of first cup portion 111 (e.g., the volume of the first internal space), and the length can be maintained even if additional space 122b is provided in second internal space 122 of second cup portion 121.

[0041] Example 2 Fig. 5 is a perspective view showing a pouch-type secondary battery 200 according to a second embodiment of the present invention. As shown in Fig. 5, the secondary battery 200 according to this embodiment differs from the secondary battery 100 according to the first embodiment in that the overlapping portion 213b of the first peripheral edge portion 213 and the second peripheral edge portion 223 are folded toward the first cup portion 211 (see Fig. 8). For reference, the contents of the second embodiment may be similarly applied to the above-mentioned embodiments, unless they are mutually contradictory.

[0042] First, the folding process will be described with reference to Figures 6 and 7. Figure 6 is a perspective view showing the secondary battery of Figure 5 before folding the peripheral portion, and Figure 7 is a cross-sectional view taken along line CC in Figure 6. A line extending parallel to the outer end of first peripheral portion 213 and spaced a first distance L1 from the outer end of first peripheral portion 213 in the horizontal direction (opposite the direction D3 in Figure 6) toward first cup portion 211 is referred to as first folding line F1. Overlapped portion 213b of first peripheral portion 213 and second peripheral portion 223 may be primarily folded toward first cup portion 211 along first folding line F1. Thereafter, a line extending parallel to the first folding line F1 and spaced a second distance L2 from the first folding line F1 toward the first cup portion 211 is referred to as a second folding line F2. The overlapping portion 213b of the first periphery 213 and the second periphery 223 may be folded a second time along the second folding line F2 toward the first cup portion 211. The secondary battery 200 of FIG. 5 may be realized by folding the battery two times. The secondary battery of this embodiment may be folded only once along the second folding line.

[0043] As shown in Fig. 8, the secondary battery of this embodiment may include a first pouch 210 having a first cup portion 211 and a first peripheral portion 213, and a second pouch 220 having a second cup portion 221 and a second peripheral portion 223, similar to the secondary battery of Example 1. Fig. 8 is a cross-sectional view taken along line BB in Fig. 5, and for ease of explanation, the electrode assembly is not shown. Second cup portion 221 of this embodiment may also include an overlapping space 222a that overlaps first internal space 212 and an additional space 222b that does not overlap first internal space 212 when projected in the first direction (D1). The first peripheral portion 213 of this embodiment may also include a non-overlapping portion 213a that does not overlap with the second peripheral portion 223, and an overlapping portion 213b that overlaps with the second peripheral portion 223, based on when projected in the direction opposite to the first direction (D2) (before folding).

[0044] As shown in FIG. 9, in comparison with the conventional folding secondary battery (upper drawing), the secondary battery of this embodiment (lower drawing) has an additional space 222b formed by utilizing a portion of the space occupied by the secondary battery due to the peripheral portion of the conventional secondary battery. Therefore, the additional space 222b can be formed while maintaining the conventional volumetric energy density, i.e., without a decrease in volumetric energy density.

[0045] Meanwhile, as shown in Fig. 8, the overlapping portion 213b and the second peripheral portion 223 of the first peripheral portion 213 may be bent toward the first cup portion 211 so as to minimize exposure outside the non-overlapping portion 213a in the horizontal direction (D3) when projected in the opposite direction (D2) to the first direction. This maximizes additional space 222b below the non-overlapping portion 213a while minimizing reduction in volumetric energy density. However, as shown in Fig. 8, portions of the overlapping portion 213b and the second peripheral portion 223 of the first peripheral portion 213 may be exposed outside the non-overlapping portion 213a of the first peripheral portion 213 during the gradual bending process.

[0046] In the secondary battery of this embodiment, the horizontal length (D3) of non-overlapping portion 213a may be a length that allows overlapping portion 213b of first peripheral portion 213 and second peripheral portion 223 to contact first cup portion 211 when bent. FIG. 8 illustrates an example in which second peripheral portion 223 contacts first cup portion 211. If non-overlapping portion 213a is long enough that overlapping portion 213b of first peripheral portion 213 and second peripheral portion 223 cannot contact first cup portion 211 even when bent to the maximum extent (e.g., horizontally), the volume of additional space 222b located below non-overlapping portion 213a becomes excessively large compared to the volume occupied by the electrode assembly inside the secondary battery, which may result in a relatively reduced capacity of the secondary battery.

[0047] 10, the secondary battery of this embodiment may further include a fixing tape 240. The fixing tape 240 may be attached to both the outer surface of the first cup portion 211 and the second periphery 223 to pull the second periphery 223 toward the first cup portion 211 and prevent the overlapping portion 213b of the first periphery 213 and the second periphery 223 from opening in a direction away from the first cup portion 211. FIG. 10 is a perspective view showing a modified example of the secondary battery of FIG. 5.

[0048] 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.

[0049] Therefore, the embodiments disclosed in the present invention are intended to explain, not to 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.

[0050] 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.

Claims

1. a first pouch including a first cup portion indented in a predetermined first direction to form a first internal space; and a first peripheral edge portion extending from the first cup portion in a predetermined horizontal direction perpendicular to the first direction and surrounding at least a portion of the first cup portion; a second cup portion disposed opposite to the first pouch and recessed in a direction opposite to the first direction to form a second internal space for accommodating an electrode assembly together with the first internal space; and a second pouch including a second peripheral portion extending in the horizontal direction from the second cup portion, surrounding at least a portion of the second cup portion, and coupled to the first peripheral portion, The second internal space is A pouch-type secondary battery including an overlapping space that overlaps the first internal space when projected in the first direction, and an additional space that extends from the overlapping space in the horizontal direction and does not overlap the first internal space.

2. The additional space of the second internal space is The pouch-type secondary battery according to claim 1 , wherein the space is a space where the electrode assembly is not disposed.

3. The additional space of the second internal space is 2. The pouch-type secondary battery according to claim 1, wherein the pouch-type secondary battery is configured to contain gas generated from the inside of the first pouch and the second pouch so as to delay a start time of discharging the gas to the outside of the first pouch and the second pouch.

4. The length of the first peripheral edge portion in the horizontal direction is The pouch-type secondary battery according to claim 1 , wherein the size is determined based on the size of the first cup portion.

5. The first peripheral portion is 2. The pouch-type secondary battery of claim 1, further comprising: a non-overlapping portion that does not overlap the second peripheral portion and is positioned to correspond to the additional space of the second internal space when projected in a direction opposite to the first direction; and an overlapping portion that extends in the horizontal direction from the non-overlapping portion and overlaps the second peripheral portion.

6. The overlapping portion of the first peripheral edge portion and the second peripheral edge portion are The pouch-type secondary battery according to claim 5 , wherein the pouch-type secondary battery is bent toward the first cup portion.

7. The overlapping portion of the first peripheral edge portion and the second peripheral edge portion are The pouch-type secondary battery according to claim 6 , wherein the pouch-type secondary battery is bent toward the first cup portion so that the non-overlapping portion is not exposed outside the horizontal direction when projected in a direction opposite to the first direction.

8. The length of the non-overlapping portion in the horizontal direction is The pouch-type secondary battery according to claim 6 , wherein the length of the first peripheral edge portion allows the overlapping portion of the first peripheral edge portion and the second peripheral edge portion to come into contact with the first cup portion when folded.

9. The overlapping portion of the first peripheral edge portion and the second peripheral edge portion are the first peripheral portion is spaced a first distance from an outer end of the horizontal direction toward the first cup portion, and is primarily folded toward the first cup portion along a first folding line that is parallel to the outer end of the first peripheral portion; 7. The pouch-type secondary battery of claim 6, wherein the pouch-type secondary battery is secondarily folded toward the first cup portion along a second folding line that is spaced a second distance from the first folding line toward the first cup portion and is parallel to the first folding line.

10. 10. The pouch-type secondary battery of claim 5, further comprising a fixing tape attached to both an outer surface of the first cup portion and the second peripheral edge portion to prevent the overlapping portion of the first peripheral edge portion and the second peripheral edge portion from opening in a direction away from the first cup portion when the second peripheral edge portion is pulled toward the first cup portion.

11. a first pouch including a first cup portion indented in a predetermined first direction to form a first internal space; and a first peripheral portion extending from the first cup portion and surrounding at least a portion of the first cup portion; a second pouch including a second cup portion disposed opposite to the first pouch and recessed in a direction opposite to the first direction to form a second internal space for accommodating an electrode assembly together with the first internal space; and a second pouch including a second peripheral portion extending from the second cup portion, surrounding at least a portion of the second cup portion, and coupled to the first peripheral portion, The second internal space is The first internal space is formed in a shape asymmetrical with the first internal space, The pouch-type secondary battery includes an additional space in which the electrode assembly is not disposed, for accommodating gas generated from inside the first pouch and the second pouch, as a space provided by the asymmetric shape.

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