Separator, electrode laminate including separator, and secondary battery including electrode laminate

Abstract

The secondary battery according to the present invention comprises: a first electrode; a second electrode alternately stacked with the first electrode along the stacking direction; and a separator provided to separate the first electrode and the second electrode from each other, wherein the separator comprises: a first separator portion positioned between the first electrode and the second electrode; a second separator portion positioned at a side opposite to the first separator portion with respect to the first electrode; and a connection portion connecting the first separator portion and the second separator portion and covering an end of the first electrode, and the connection portion has a gas discharge hole formed therein, the gas discharge hole having a length in a longitudinal direction parallel to a direction in which the end of the first electrode extends and a rounded corner, the length being longer than the width thereof.

Description

Separator, electrode stack including separator, and secondary battery including electrode stack

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority based on Korean patent application 10-2024-0153027 filed on October 31, 2024, and all contents disclosed in the literature of said Korean patent applications are incorporated herein as part of this specification.

[0003] [Technology Field]

[0004] The present invention relates to a separator, an electrode stack including the separator, and a secondary battery including the electrode stack. More specifically, the invention relates to a separator configured to facilitate gas discharge, an electrode stack including the separator, and a secondary battery including the electrode stack.

[0005] Generally, a secondary battery configured to produce electricity includes an electrode stack comprising a plurality of electrodes and a separator positioned between each electrode, and a battery case housing the electrode stack.

[0006] Among the processes involved in manufacturing secondary batteries is the degassing process. The degassing process is performed after the activation process, in which the battery is activated by housing the electrode stack in the battery case and performing preliminary charging and discharging. More specifically, gas is generated as the electrolyte reacts with the electrodes during the activation process, and the degassing process is designed to remove this gas. If the gas is not removed from the secondary battery, it hinders the movement of ions, such as lithium ions, between the electrodes, leading to a decrease in electricity generation.

[0007] When a separator is formed by being composed of multiple individual sheets separated from one another, it may be easy for gas to move between adjacent separators. However, if adjacent separators are connected to each other, or if a single separator separates each of the multiple electrodes, a problem may arise where it is difficult for gas to move to a part of the separator. In other words, a problem may arise where gas is trapped between the separator and the electrode.

[0008] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the content of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application.

[0009] The present invention has been devised to solve the above problems, and the objective of the present invention is to facilitate the movement of gas through a separator to prevent gas trapping.

[0010] The technical problems to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0011] A secondary battery according to one embodiment of the present invention comprises a first electrode, a second electrode stacked alternately with the first electrode along a stacking direction, and a separator arranged to separate the first electrode and the second electrode from each other. The separator comprises a first separator portion located between the first electrode and the second electrode, a second separator portion located on the opposite side of the first separator portion with respect to the first electrode, and a connecting portion connecting the first separator portion and the second separator portion and covering the end of the first electrode. The connecting portion has a gas discharge hole formed therein, the length in the longitudinal direction parallel to the extension direction of the end of the first electrode is longer than the width and the corner is rounded.

[0012] The longitudinal end of the gas discharge hole can be drawn inward as it extends outward in the width direction.

[0013] The gas exhaust holes may be provided in multiple numbers and arranged along the extension direction of the first electrode end.

[0014] The connecting portion may include a bridge portion connecting the first membrane portion and the second membrane portion between a plurality of gas discharge holes.

[0015] The length of the gas discharge hole in the first electrode extension direction may be longer than the length in the extension direction of the first electrode of the bridge part.

[0016] The length of the first electrode extension direction of the bridge portion may be 1 / 10 or less of the length of the first electrode extension direction of the connecting portion.

[0017] The width of the bridge portion connected to the first membrane portion or the second membrane portion may be larger than the width located between the first membrane portion and the second membrane portion.

[0018] The bridge portion may include a space-forming portion that is opposite and spaced apart so that a gas movement space is formed between it and the first electrode.

[0019] It further includes an end bridge portion located on the outer side relative to the arrangement direction of a plurality of gas discharge holes, and the width of the end bridge portion may be wider than the width of the bridge portion.

[0020] The gas discharge hole can be bent from the end of the first electrode toward the first separator portion or the second separator portion.

[0021] The gas exhaust hole can have a width greater than the thickness of the first electrode end.

[0022] The gas exhaust hole may overlap with the first electrode and the stacking direction so that the first electrode is exposed with respect to the stacking direction.

[0023] The gas exhaust hole may be configured to limit overlap with the second electrode in order to prevent the first electrode and the second electrode from coming into contact.

[0024] It includes a receiving portion that accommodates a first electrode, a second electrode, and a separator, and a side portion configured to extend from one side of the receiving portion and be sealed, and a gas discharge hole may be configured to face the side portion.

[0025] A connecting portion is defined as a first connecting portion, and the first connecting portion is connected to one end of a first separator portion and one end of a second separator portion adjacent to one end of the first separator portion, and the separator may further include a second connecting portion connected to a third separator portion located on the opposite side of the first separator portion with respect to the second electrode, another end of the second separator portion and one end adjacent to the other end of the second separator portion of the third separator portion.

[0026] An electrode laminate according to one embodiment of the present invention comprises a first electrode, a second electrode stacked alternately with the first electrode along a stacking direction, a first separator portion located between the first electrode and the second electrode, a second separator portion located on the opposite side of the first separator portion with respect to the first electrode, and a connecting portion connecting the first separator portion and the second separator portion and covering the end of the first electrode, wherein the connecting portion has a gas discharge hole formed therein that allows gas to move and overlaps with respect to the stacking direction with respect to either the first electrode or the second electrode, and prevents overlap with respect to the other.

[0027] The gas discharge hole may have a length in the longitudinal direction parallel to the extension direction of the end of the first electrode that is longer than its width, and the corners may be rounded.

[0028] The longitudinal end of the gas discharge hole can be drawn inward as it extends outward in the width direction.

[0029] The gas exhaust holes may be provided in multiple numbers and arranged along the extension direction of the end of the first electrode.

[0030] A separator according to one embodiment of the present invention comprises a first separator portion configured to face a first surface of a first electrode, a second separator portion configured to face a second surface opposite to the first surface of the first electrode, and a connecting portion configured to connect the first separator portion and the second separator portion, wherein the connecting portion comprises a plurality of gas discharge holes having a longitudinal length longer than the width, a bridge portion formed between the plurality of gas discharge holes, and an end bridge portion formed on the outer side of the plurality of gas discharge holes, wherein the length of the gas discharge hole is longer than the length of the bridge portion, and the length of the end bridge portion is longer than the length of the bridge portion.

[0031] A separation membrane according to one embodiment of the present invention is provided with a gas discharge hole, so that gas is not trapped and can move easily.

[0032] The gas discharge hole formed in the separator according to one embodiment of the present invention has rounded corners, thereby preventing the formation of cracks at the corners.

[0033] According to one embodiment of the present invention, a plurality of gas discharge holes formed in a separator are formed to be longer than the bridge portion located between the plurality of gas discharge holes, thereby making it easier to discharge gas.

[0034] A gas discharge hole formed in a separator according to one embodiment of the present invention overlaps with a part of the first electrode and does not overlap with the second electrode adjacent to the first electrode, thereby facilitating the discharge of gas while simultaneously preventing a short circuit from occurring between the first electrode and the second electrode.

[0035] An electrode laminate and a secondary battery according to one embodiment of the present invention may have the above effects by including the above separator.

[0036] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0037] FIG. 1 is an assembly diagram of a secondary battery according to a first embodiment of the present invention.

[0038] Figure 2 is a cross-sectional view showing the battery cases illustrated in Figure 1 cut while in contact with each other.

[0039] FIG. 3 is a side view showing the electrode assembly illustrated in FIG. 2 as viewed from the side.

[0040] FIG. 4 is a cross-sectional view showing the first electrode, second electrode, and separator shown in FIG. 3 cut.

[0041] FIG. 5 is a perspective view illustrating the first electrode, the second electrode, and the separator shown in FIG. 4.

[0042] FIG. 6 is a front view of the first electrode, second electrode, and separator shown in FIG. 5, viewed from above.

[0043] Figure 7 is a perspective view illustrating the separation membrane shown in Figure 6.

[0044] Figure 8 is an enlarged view showing the portion where the gas discharge hole shown in Figure 6 is located.

[0045] FIG. 9 is an enlarged view illustrating a separation membrane according to a second embodiment of the present invention.

[0046] FIG. 10 is an enlarged view illustrating a separation membrane according to a third embodiment of the present invention.

[0047] FIG. 11 is an enlarged view illustrating a separation membrane according to a fourth embodiment of the present invention.

[0048] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0049] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0050] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0051] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0052] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0053] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0054] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0055] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components.

[0056] Terms such as “first,” “second,” or “first” or “second” may be used simply to distinguish one component from another and do not limit the components in other aspects (130a-1) (e.g., importance or order).

[0057] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0058] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0059] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0060] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0061] Meanwhile, terms such as "up-and-down direction," "downward side," and "front-backward direction" used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0062] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0063] First embodiment

[0064] FIG. 1 is an assembly diagram of a secondary battery (B) according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the battery case (300) shown in FIG. 1 cut in a state where they are in contact with each other. FIG. 3 is a side view showing the electrode assembly (EA) shown in FIG. 2 viewed from the side.

[0065] As illustrated in FIGS. 1 to 3, a secondary battery (B) according to the first embodiment of the present invention is described.

[0066] As illustrated in FIG. 1, a secondary battery (B) may be provided to generate electricity. The secondary battery (B) may include an electrode assembly (EA) and a battery case (300) configured to accommodate the electrode assembly (EA). The type of the secondary battery (B) may vary depending on the type of the battery case (300). More specifically, the battery case (300) may be provided as a pouch, and the secondary battery (B) may be pouch-type. However, if necessary, the secondary battery (B) may be prismatic or cylindrical.

[0067] The electrode assembly (EA) may include an electrode stack (ES) formed by stacking electrodes (100), an electrode lead (10) connected to a plurality of electrode tabs (101) each electrode (100), and a lead film (20) coupled to the electrode lead (10). At this time, the electrode assembly (EA) may include a separator (200) that separates the plurality of electrodes (100) as shown in FIG. 2. As shown in FIG. 2, the separator (200) is formed integrally and can pass between the plurality of electrodes (100) in a zigzag pattern. The zigzag separator (200) has the advantage of forming a stable secondary battery (B) by reducing the possibility of a short circuit occurring between adjacent electrodes (100). However, the separator (200) may be provided in multiple numbers as needed, and each separator (200) may be positioned between adjacent electrodes (100).

[0068] The battery case (300) may include a receiving portion (310) configured to accommodate an electrode assembly (EA) and a side portion (320) extending from the receiving portion (310). The receiving portion (310) may be formed by pressing and stretching a pouch. The receiving portion (310) may be formed concavely so that a battery receiving space (310S) is formed on the inside. At this time, the receiving portion (310) may be provided in a pair so that an electrode stack (ES) is accommodated between the pair of receiving portions (310). The side portion (320) may include a folding portion (323) located between a pair of receiving portions (310), a degas sealing portion (322) extending in a direction away from the outer edge of each of the pair of receiving portions (310), and / or a lead sealing portion (321) extending in a direction perpendicular to the degas sealing portion (322) from each of the pair of receiving portions (310). In this case, the lead sealing portion (321) may, if necessary, have a configuration that extends in the direction of extension of the degas sealing portion (322) from an extension point different from the extension point of the degas sealing portion (322). The battery case (300) may be folded so that the folding portion (323) is folded so that a pair of receiving portions (310) face each other. Accordingly, the lead sealing portions (321) of the battery case (300) may be configured to be in contact with each other, and the degas sealing portions (322) may be configured to be in contact with each other. A lead film (20) may be positioned at the location where the lead sealing portions (321) are in contact with each other, so that the electrode lead (10) may be configured to extend to the outside of the battery case (300).

[0069] The secondary battery (B) that has completed the above process can be completed through the following process.

[0070] After the battery case (300) containing the electrode assembly (EA) is folded, the opposing lead sealing portions (321) may be fused together and sealed by applying heat and pressure. After the lead sealing portions (321) are sealed, the electrolyte may flow into the battery receiving space (310S) through the gap between the ends of the degas sealing portions (322) that are not yet sealed. After that, after sealing a part of the degas sealing portions (322), an activation process may be performed to perform preliminary charging and discharging. Accordingly, the electrode (100) and the electrolyte may react to generate gas. To remove the generated gas, a hole may be formed in the degas sealing portions (322) and negative pressure may be applied to discharge the gas. Afterwards, a trimming process is performed to cut the degas sealing portion (322) in which the hole is formed, and a side folding process can be performed to fold the remaining degas sealing portion (322) to reduce its width.

[0071] At this time, as illustrated in FIG. 3, a phenomenon may occur in which gas that needs to be removed in the degas process is located between the separator (200) and the electrode (100) and trapped. If the gas is not removed from the secondary battery (B), it hinders the movement of ions such as lithium ions between the electrodes (100), which may result in a decrease in the amount of electricity generated. Furthermore, if the gas is trapped, a problem may occur in which the separator (200) located adjacent to the trapped gas is not properly impregnated with the electrolyte. A problem may occur in which the separator (200) that is not impregnated with the electrolyte has a reduced function as a pathway for ion movement. As shown in the drawing of the electrode assembly (EA) in FIG. 3, the trapped gas may be located in the upper inner part of the electrode assembly (EA). Since the gas is lighter than the electrolyte, it has the property of moving upward within the electrolyte, and its movement may be blocked by the separator (200) and trapped. At this time, as indicated by the arrows on both ends of the electrode assembly (EA) shown in Fig. 3, if gas is discharged only through the ends of the separator (200), the gas can be trapped in the upper inner part of the separator (200) to hinder the movement of ions.

[0072] Hereinafter, a separator (200) for solving the above problem is described. However, prior to that, the specific structure of the separator (200) is described assuming that the separator (200) has a zigzag shape as shown in FIG. 2. The electrode (100) separated by the separator (200) may include a first electrode (110) and a second electrode (120) that is alternately stacked along the stacking direction with respect to the first electrode (110) facing the first electrode (110). The stacking direction may be left and right directions based on FIG. 2. Here, the first electrode (110) may mean a negative electrode and the second electrode (120) may mean a positive electrode. However, if necessary, the first electrode (110) may be a positive electrode and the second electrode (120) may be a negative electrode. As shown in FIG. 2, the separator (200) may include a first separator portion (211) located between the first electrode (110) and the second electrode (120), a second separator portion (212) located on the opposite side of the first separator portion (211) with respect to the first electrode (110), and a third separator portion (213) located on the opposite side of the first separator portion (211) with respect to the second electrode (120). Furthermore, the separator (200) may include a first connecting portion (220a) connected to one end of the first separator portion (211) and one end of the second separator portion (212) adjacent to the first separator portion (211), and a second connecting portion (220b) connected to the other end of the second separator portion (212) and one end of the third separator portion (213) adjacent to the second separator portion (212). At this time, when the first connecting portion (220a) is referred to alone, it may be referred to as the connecting portion (220). In this case, the connecting portion (220) may be defined as connecting the first separator portion (211) and the second separator portion (212) and covering the end of the first electrode (110). The structure of the separator (200) that facilitates gas discharge will be described in detail below with reference to the drawings.

[0073] FIG. 4 is a cross-sectional view showing the first electrode (110), the second electrode (120), and the separator (200) shown in FIG. 3. FIG. 5 is a perspective view showing the first electrode (110), the second electrode (120), and the separator (200) shown in FIG. 4. FIG. 6 is a front view of the first electrode (110), the second electrode (120), and the separator (200) shown in FIG. 5, viewed from above.

[0074] With reference to FIGS. 4 to 6, the structure of a separation membrane (200) that facilitates gas discharge according to the first embodiment of the present invention will be explained.

[0075] As illustrated in FIG. 5, the connecting portion (220) may have a plurality of gas discharge holes (223H) formed therein. However, the gas discharge hole (223H) may be formed as a single one as needed. The gas discharge holes (223H) may be provided in plurality and arranged along the extension direction of the end of the first electrode (110). More specifically, the extension direction of the end of the first electrode (110) may be the front-rear direction with respect to FIG. 5. As illustrated in FIG. 5, six gas discharge holes (223H) may be provided along the front-rear direction. However, the number of gas discharge holes (223H) may be changed as needed.

[0076] Additionally, the part referred to as the first electrode (110) may be understood as being substituted for the second electrode (120) as needed. The content applied based on the first electrode (110) in the present disclosure may be seen as being applied to the second electrode (120) or simultaneously applied to the first electrode (110) and the second electrode (120).

[0077] The gas discharge hole (223H) may be formed such that the length (D1) in the longitudinal direction parallel to the extension direction of the end of the first electrode (110) is longer than the width (D2). The connecting portion (220) may include a bridge portion (221) between a plurality of gas discharge holes (223H). The bridge portion (221) may connect the first separator portion (211) and the second separator portion (212). The length (D1) of the gas discharge hole (223H) in the extension direction of the first electrode (110) may be longer than the length (W2) of the bridge portion (221) in the extension direction of the first electrode (110). Accordingly, the length occupied by the gas discharge hole (223H) may be longer than that of the bridge portion (221) with respect to the extension direction of the first electrode (110). More specifically, for example, the length of the first electrode (110) in the extension direction of the bridge portion (221) may be 1 / 10 or less of the length of the first electrode (110) in the extension direction of the connecting portion (220). Thus, compared to the case where the length of the bridge portion (221) is longer than the gas discharge hole (223H), gas can be discharged more effectively through the extension portion.

[0078] The gas discharge hole (223H) may be formed with rounded corners. Accordingly, the gas discharge hole (223H) may be formed to be substantially close to an elliptical shape. In other words, the longitudinal end of the gas discharge hole (223H) may be drawn inward as it extends outward in the width direction. If the corners of the gas discharge hole (223H) are formed at an angle, stress may be concentrated at the corner portion, making it highly likely that cracks or tears will occur at the corner portion. As in the first embodiment of the present invention, if the corners are formed at a rounded shape, stress is distributed, and the likelihood of tearing or cracking occurring is reduced. Furthermore, the width (W1) of the bridge portion (221) connected to the first separator portion (211) or the second separator portion (212) may be greater than the width (W2) located between the first separator portion (211) and the second separator portion (212). The part where the bridge part (221) and the first separator part (211) or the second separator part (212) are connected is a part where the width changes abruptly and significantly, so stress may be concentrated therein, but since the thickness of this part is made thick, the possibility of damage to the bridge part (221) can be reduced.

[0079] The separator (200) may further include an end bridge portion (222) located on the outer side relative to the arrangement direction of a plurality of gas discharge holes (223H). The width of the end bridge portion (222) may be wider than the width (W2) of the bridge portion (221). One end of the end bridge portion (222) may be formed as a free end, so the resistance to breakage may be low. Furthermore, since the end bridge portion (222) is located on the outer side compared to the bridge portion (221), the possibility of impact being applied may be higher than that of the bridge portion (221). Therefore, the end bridge portion (222) may need to have a stronger resistance to breakage than the bridge portion (221). The end bridge portion (222) according to the first embodiment may have a stronger resistance to breakage by being formed with a wide width. Furthermore, if the end bridge section (222) is damaged, the bridge section (221) closest to the end bridge section (222) becomes the end again and is exposed to impact, so it may be even more necessary to prevent damage to the end bridge section (222) in order to prevent damage to the bridge section (221).

[0080] The bridge portion (221) may include a space-forming portion (221a) that is opposite and spaced apart so that a gas movement space (221S) is formed between it and the first electrode (110). As shown in FIG. 4, the space-forming portion (221a) may have an arc-shaped cross-section. The gas discharge hole (223H) may be a passage through which gas that can be trapped in the gas movement space (221S) is moved.

[0081] As shown in FIG. 5, the gas discharge hole (223H) can be bent toward the first separator portion (211) and the second separator portion (212) at the end of the first electrode (110). However, depending on the need, only the portion of the gas discharge hole (223H) closer to the first separator portion (211) may be bent, or only the portion closer to the second separator portion (212) may be bent. Furthermore, the bridge portion (221) can be bent toward the first separator portion (211) or the second separator portion (212) at the end of the first electrode (110).

[0082] The gas exhaust hole (223H) may have a width greater than the thickness of the end of the first electrode (110). Accordingly, the bending gas exhaust hole (223H) may overlap with the first electrode (110) in the stacking direction so that the first electrode (110) is exposed in the stacking direction. At this time, as shown in FIG. 4, the first electrode (110) may protrude beyond the second electrode (120). The gas exhaust hole (223H) may be configured so that the overlap with the second electrode (120) is limited to prevent contact between the first electrode (110) and the second electrode (120). That is, as shown in FIG. 6, the gas exhaust hole (223H) may not extend beyond the second electrode (120). In other words, the connecting portion (220) is movable with respect to the stacking direction with respect to either the first electrode (110) or the second electrode (120), and overlap with respect to the other.

[0083] As illustrated in FIG. 2, the gas discharge hole (223H) may be configured to face the side portion (320). Since the part of the separator (200) facing the side portion (320) is a location where gas is easily trapped, the gas discharge hole (223H) may be formed accordingly. In other words, based on FIG. 2, the gas discharge hole (223H) may be located on the upper side of the electrode stack (ES). However, if necessary, the gas discharge hole (223H) may be located on both the upper and lower sides of the electrode stack (ES).

[0084] FIG. 7 is a perspective view illustrating the separator (200) illustrated in FIG. 6. FIG. 8 is an enlarged view illustrating the portion where the gas discharge hole (223H) illustrated in FIG. 6 is located.

[0085] Referring to FIGS. 7 and 8, a separator (200) according to the first embodiment of the present invention will be described.

[0086] The separator (200) may be formed by winding as shown in FIG. 7. The separator (200) may include a first separator portion (211) configured to face a first surface of the first electrode (110), a second separator portion (212) configured to face a second surface opposite to the first surface of the first electrode (110), and a connecting portion (220) configured to connect the first separator portion (211) and the second separator portion (212). The connecting portion (220) may include a plurality of gas discharge holes (223H) having a longitudinal length longer than the width, a bridge portion (221) formed between the plurality of gas discharge holes (223H), and an end bridge portion (222) formed on the outer side of the plurality of gas discharge holes (223H). The length of the gas discharge holes (223H) may be longer than the length of the bridge portion (221). The length of the end bridge section (222) may be longer than the length of the bridge section (221).

[0087] The first embodiment and other embodiments are described below. Content common to the first embodiment will be omitted as much as possible, and the other embodiments will be described focusing on the differences. In other words, it is obvious that if content not explained in the other embodiments is necessary, it can be supplemented through the content of the first embodiment.

[0088] 2nd embodiment

[0089] FIG. 9 is an enlarged view illustrating a separator (200) according to a second embodiment of the present invention.

[0090] Referring to FIG. 9, a gas discharge hole (223H-1) according to a second embodiment of the present invention will be described.

[0091] The second embodiment differs from the first embodiment in that the shape of the gas discharge hole (223H-1) is different.

[0092] The gas exhaust hole (223H-1) may have a substantially rectangular shape. Although such a gas exhaust hole (223H-1) is more likely to crack than the gas exhaust hole (223H) of the first embodiment, it has the advantage of being easy to manufacture.

[0093] Third embodiment

[0094] FIG. 10 is an enlarged view illustrating a separator (200) according to a third embodiment of the present invention.

[0095] Referring to FIG. 10, a gas discharge hole (223H-2) according to a third embodiment of the present invention will be described.

[0096] The third embodiment differs from the first embodiment in that the shape of the gas discharge hole (223H-2) is different.

[0097] The gas exhaust hole (223H-2) may be substantially circular. A circular gas exhaust hole (223H-2) has the advantage of having strong resistance against cracking because the applied stress is evenly distributed. However, it has a disadvantage in that more gas exhaust holes (223H-2) than in the first embodiment must be formed to facilitate gas exhaust.

[0098] 4th embodiment

[0099] FIG. 11 is an enlarged view illustrating a separator (200) according to a fourth embodiment of the present invention.

[0100] Referring to FIG. 11, a gas discharge hole (223H-3) according to the fourth embodiment of the present invention will be described.

[0101] The fourth embodiment differs from the first embodiment in that the shape of the gas discharge hole (223H-3) is different.

[0102] Despite its name, the gas discharge hole (223H-3) may have the shape of a cut line. When gas is discharged, the cut part opens up, making it easier to discharge the gas.

[0103] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, unless explicitly limited in the combination of any embodiment with another, it should be considered that combinations between embodiments are possible. Any combination of any embodiment with another embodiment is deemed to be disclosed herein.

[0104] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0105] [Explanation of the symbol]

[0106] B: Secondary battery

[0107] EA: Electrode assembly

[0108] 10: Electrode Lead

[0109] 20: Lead film

[0110] ES: Electrode laminate

[0111] 100: Electrode

[0112] 101: Electrode tab

[0113] 110: First electrode

[0114] 120: Second electrode

[0115] 200: Separator

[0116] 211: First separator section

[0117] 212: Second separator section

[0118] 213: Third separator section

[0119] 220: Connection part

[0120] 220a: First connecting part

[0121] 220b: Second connecting part

[0122] 221: Bridge section

[0123] 221a: Space forming part

[0124] 221S: Gas transport space

[0125] 222: End bridge section

[0126] 223H, 223H-1, 223H-2, 223H-3: Gas exhaust holes

[0127] 300: Battery case

[0128] 310: Reception Department

[0129] 310S: Battery compartment

[0130] 320: Side

[0131] 321: Lead sealing section

[0132] 322: Digas sealing section

[0133] 323: Folding section

Claims

First electrode; A second electrode stacked alternately with the first electrode along the stacking direction; and It includes a separator arranged to separate the first electrode and the second electrode from each other, The above separator is, A first separator portion located between the first electrode and the second electrode; A second separator portion located on the opposite side of the first separator portion with respect to the first electrode; and It includes a connecting portion that connects the first separator portion and the second separator portion and covers the end of the first electrode, The above connecting portion is a secondary battery in which a gas discharge hole is formed with a length in the longitudinal direction parallel to the extension direction of the end of the first electrode that is longer than the width and has rounded corners. In paragraph 1, A secondary battery in which the longitudinal end of the above gas discharge hole is drawn inward as it extends outward in the width direction. In paragraph 1, A secondary battery having a plurality of gas discharge holes arranged along the extension direction of the first electrode end. In paragraph 3, The above connecting portion is a secondary battery comprising a bridge portion connecting the first separator portion and the second separator portion between a plurality of the above gas discharge holes. In paragraph 4, A secondary battery in which the length of the gas discharge hole in the first electrode extension direction is longer than the length of the first electrode in the bridge portion in the extension direction. In paragraph 4, A secondary battery in which the length of the first electrode extension direction of the bridge portion is 1 / 10 or less of the length of the first electrode extension direction of the connecting portion. In paragraph 4, The above bridge portion is a secondary battery in which the width of the portion connected to the first separator portion or the second separator portion is greater than the width located between the first separator portion and the second separator portion. In paragraph 4, A secondary battery comprising a space-forming portion that is opposite and spaced apart so as to form a gas movement space between the bridge portion and the first electrode. In paragraph 4, It further includes an end bridge portion located on the outer side with respect to the arrangement direction of a plurality of the above gas discharge holes, and A secondary battery in which the width of the end bridge portion is wider than the width of the bridge portion. In paragraph 1, The above gas discharge hole is a secondary battery that is bent toward the first separator portion or the second separator portion at the end of the first electrode. In paragraph 1, The above gas discharge hole is a secondary battery having a width greater than the thickness of the first electrode end. In paragraph 1, The above gas exhaust hole is a secondary battery that overlaps with the first electrode and the stacking direction so that the first electrode is exposed with respect to the stacking direction. In paragraph 1, A secondary battery in which the above gas exhaust hole is configured to limit overlap with the second electrode in order to prevent the first electrode and the second electrode from coming into contact. In paragraph 1, It includes a receiving portion for accommodating the first electrode, the second electrode, and the separator, and a side portion configured to extend from one side of the receiving portion and be sealed. A secondary battery in which the above gas discharge hole is configured to face the above side portion. In paragraph 1, The above connection part is defined as a first connection part, and The first connecting portion is connected to one end of the first separator portion and one end of the second separator portion adjacent to the one end of the first separator portion, and The above separator is, A third separator portion located on the opposite side of the first separator portion with respect to the second electrode; and A secondary battery further comprising a second connecting portion connected to the other end of the second separator portion and the first end of the third separator portion adjacent to the other end of the second separator portion. First electrode; A second electrode stacked alternately with the first electrode along the stacking direction; and A first separator portion located between the first electrode and the second electrode; A second separator portion located on the opposite side of the first separator portion with respect to the first electrode; and It includes a connecting portion that connects the first separator portion and the second separator portion and covers the end of the first electrode, The above connecting portion is an electrode stack having a gas discharge hole formed therein that allows gas to move and overlaps with respect to the stacking direction with respect to either the first electrode or the second electrode, and prevents overlap with respect to the other. In Paragraph 16, The above gas discharge hole is an electrode laminate in which the length in the longitudinal direction parallel to the extension direction of the end of the first electrode is longer than the width and the corners are rounded. In Paragraph 16, The longitudinal end of the above gas discharge hole is an electrode laminate that is drawn inward as it extends outward in the width direction. In Paragraph 16, The above gas exhaust holes are provided in plurality, and the electrode stack is arranged along the extension direction of the end of the first electrode. A first separator portion configured to face the first surface of the first electrode; A second separator portion configured to face a second surface opposite to the first surface of the first electrode; and It includes a connecting portion configured to connect the first separator portion and the second separator portion, The above connecting portion includes gas discharge holes provided in plurality, the length in the longitudinal direction being longer than the width, a bridge portion formed between the plurality of gas discharge holes, and an end bridge portion formed on the outer side of the plurality of gas discharge holes. The length of the gas discharge hole is longer than the length of the bridge part, and A separator in which the length of the end bridge portion is longer than the length of the bridge portion.

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