Secondary battery

Abstract

The present invention relates to a secondary battery and, more specifically, to a secondary battery which can be repeatedly charged and discharged. A secondary battery according to an embodiment of the present invention comprises: an electrode assembly comprising electrodes and a separator; a housing accommodating the electrode assembly; an electrode lead connected to the electrode assembly and protruding to the outside of the housing; a lead film covering at least a part of the electrode lead such that the electrode lead is insulated from the housing; and a gas discharge guide portion provided between the electrode lead and the lead film and forming a gas discharge path through which gas inside the housing is discharged to the outside when the internal pressure of the housing increases, wherein a gap between one end of the lead film adjacent to the electrode assembly and the gas discharge guide portion may be narrower than a gap between the other end of the lead film and the gas discharge guide portion.

Description

secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0114614, filed August 26, 2024, and Korean Patent Application No. 10-2025-0111355, filed August 12, 2025, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery, and more specifically, to a secondary battery capable of being repeatedly charged and discharged.

[0005] Secondary batteries capable of repeated charging and discharging can be categorized into cylindrical, square, and pouch-type batteries based on their shape. Among these, pouch-type secondary batteries use a sheet-type outer packaging material composed of a metal layer (foil) and a multilayer film of resin layers coated on both sides of the metal layer, which can significantly reduce the weight of the battery compared to cylindrical or square batteries that use metal cans.

[0006] The outer shell of these pouch-type secondary batteries may contain an electrolyte together with an electrode assembly. At this time, residual moisture in the electrolyte or moisture that has penetrated from the outside may react with lithium salts to generate HF (hydrogen fluoride), and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to the decomposition of the electrolyte.

[0007] Additionally, depending on the material of the positive electrode included in the electrode assembly of a pouch-type secondary battery, hydrogen and HF may be additionally generated, which may lead to overheating and internal short-circuiting during the charging and discharging process of the secondary battery. Consequently, a large amount of gas may be generated within the outer packaging.

[0008] This gas increases the internal pressure of the outer packaging, which can lead to swelling (inflating the outer packaging) or venting (rupturing a portion of the outer packaging). Therefore, pouch-type secondary batteries require a structure capable of efficiently discharging the gases within the outer packaging to prevent swelling or venting.

[0009] The present invention was conceived in recognition of the above problems, and the purpose of the present invention is to provide a secondary battery having a structure capable of efficiently discharging internal gas of an outer material.

[0010] A secondary battery according to the present invention comprises: an electrode assembly including an electrode and a separator; an outer case accommodating the electrode assembly; an electrode lead connected to the electrode assembly and protruding to the outside of the outer case; a lead film covering at least a portion of the electrode lead so as to insulate the electrode lead from the outer case; and a gas discharge guide provided between the electrode lead and the lead film and forming a gas discharge path through which internal gas of the outer case is discharged to the outside when internal pressure of the outer case increases, wherein a gap between one end of the lead film adjacent to the electrode assembly and the gas discharge guide may be narrower than a gap between the other end of the lead film and the gas discharge guide.

[0011] The above gas discharge path can be formed between one side of the gas discharge induction unit and the lead film.

[0012] The shape of the above gas discharge path may correspond to the shape of the above gas discharge induction part.

[0013] A secondary battery characterized in that a first portion of the lead film facing the gas discharge induction portion maintains a non-adhesive state with the gas discharge induction portion, and a second portion of the lead film between the gas discharge induction portion and the internal space of the outer material is more weakly adhered to the electrode lead than the remaining portions of the lead film excluding the first and second portions.

[0014] The above gas discharge induction unit may include a first member extending along the width direction of the electrode lead; and a second member extending from one end of the first member toward the internal space of the outer material.

[0015] The width of the first member may be greater than the width of the second member.

[0016] A plurality of second members may be connected to one end of the first member.

[0017] A first portion of the lead film facing the gas discharge induction portion may maintain a non-adhesive state with the gas discharge induction portion, and a second portion of the lead film between the second member and the internal space of the outer material may be more weakly adhered to the electrode lead than the remaining portions of the lead film excluding the first and second portions.

[0018] The gap between one end of the lead film adjacent to the electrode assembly and the second member may be narrower than the gap between the other end of the lead film and the first member.

[0019] A gas absorbing member that absorbs the internal gas may be provided in the above gas discharge path.

[0020] The above gas absorbing member may include a carbon dioxide absorbent that absorbs carbon dioxide among the internal gas.

[0021] The above gas absorbing member may be a solid powder containing potassium carbonate or sodium carbonate.

[0022] The above gas absorbing member is a sheet-shaped member attached to the above gas discharging member, and may include potassium carbonate or sodium carbonate.

[0023] According to one embodiment of the present invention, a secondary battery may include a gas discharge guide provided between an electrode lead and a lead film, the gas discharge guide forming a gas discharge path through which internal gas of the outer casing is discharged to the outside when the internal pressure of the outer casing increases. Here, a gap between one end of the lead film adjacent to the electrode assembly and the gas discharge guide may be formed narrower than a gap between the other end of the lead film and the gas discharge guide. In this case, even when gas is generated inside the outer casing, the internal gas of the outer casing can be effectively discharged without damaging the outer casing.

[0024] Meanwhile, the effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in the present specification.

[0025] Figure 1 is a perspective view illustrating a secondary battery according to the present invention.

[0026] Fig. 2 is a cross-sectional view showing a portion of a cross-section taken along line A-A' of Fig. 1.

[0027] Figure 3 is a drawing showing a gas discharge induction section provided between an electrode lead and a lead film.

[0028] Figure 4 is a drawing for explaining that a portion between a gas discharge induction portion of a lead film and an internal space of an outer material is less bonded to an electrode lead than other portions of the lead film.

[0029] FIG. 5 is a drawing for explaining that a portion between the second member of the lead film and the inner space of the outer material is less adhered to the electrode lead than other portions of the lead film.

[0030] Figure 6 is a drawing showing a gas absorption member provided in a gas discharge path.

[0031] Figure 7 is a drawing showing a gas absorbing member in the form of a solid powder.

[0032] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0033] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0034] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0035] Hereinafter, a secondary battery according to the present invention will be described with reference to the drawings.

[0036] Example 1

[0037] Fig. 1 is a perspective view illustrating a secondary battery according to the present invention. Fig. 2 is a cross-sectional view illustrating a portion of a section taken along line A-A' of Fig. 1. Fig. 3 is a drawing showing a gas discharge induction section provided between an electrode lead and a lead film.

[0038] Referring to FIGS. 1 to 3, a secondary battery (10) according to a first embodiment of the present invention may include an electrode assembly (100) including an electrode and a separator, an outer case (140) accommodating the electrode assembly (100), an electrode lead (110) connected to the electrode assembly (100) and protruding to the outside of the outer case (140), a lead film (120) covering at least a portion of the electrode lead (110) so that the electrode lead (110) is insulated from the outer case (140), and a gas discharge induction unit (130) provided between the electrode lead (110) and the lead film (120) and forming a gas discharge path (S) through which internal gas of the outer case (140) is discharged to the outside when the internal pressure of the outer case (140) increases. At this time, the gap (d1) between one end of the lead film (120) adjacent to the electrode assembly (100) and the gas discharge induction part (130) may be formed narrower than the gap (d2) between the other end of the lead film (120) and the gas discharge induction part (130).

[0039] The secondary battery (10) according to the first embodiment of the present invention can effectively discharge internal gas without damaging the outer case (140) even when gas is generated inside the outer case (140) as charging and discharging are repeated. Specifically, the internal gas of the outer case (140) can flow into the gas discharge path (S) through the inner portion (d1) of the lead film (120).

[0040] In this case, since the length of the inner portion (d1) of the lead film (120) is shorter than the length of the outer portion (d2) of the lead film (120), the length of the inlet path through which the internal gas of the outer material (140) flows into the gas discharge path (S) can be formed relatively short. Accordingly, since the internal gas of the outer material (140) flows into the gas discharge path (S) relatively easily, the internal gas of the outer material (140) can be efficiently discharged.

[0041] In addition, as the secondary battery (10) is repeatedly charged and discharged, when the internal pressure of the outer casing (140) increases, the inner part (d1) of the lead film (120) may be pushed outward, and the internal gas of the outer casing (140) may flow into the gas discharge path (S) through the open part. At this time, the length of the inner part (d1) of the lead film (120) is shorter than the length of the outer part (d2) of the lead film (120), so the length of the part of the lead film (120) that is pushed to open the gas discharge path (S) may be relatively short. In this case, the gas discharge path (S) can be opened relatively easily, so the internal gas of the outer casing (140) can be easily discharged.

[0042] The secondary battery (10) may have a form in which the electrode assembly (100) is housed within an outer case (140). For example, the secondary battery (10) according to the present invention may refer to a pouch-type secondary battery among various forms of secondary batteries capable of being charged and discharged. This is merely one example, and the shape of the secondary battery (10) may vary.

[0043] The electrode assembly (100) may include an anode, a cathode, and a separator. Here, the separator may be placed between the anode and the cathode to physically separate the anode and the cathode. The electrode assembly (100) may be in a form in which the anode, the cathode, and the separator are laminated, or in a jelly-roll form in which the anode, the cathode, and the separator are wound.

[0044] The electrode assembly (100) may be accommodated inside an outer material (140). The outer material (140) may be a pouch-shaped outer material including an inner layer, a metal layer, and an outer layer. Here, the inner layer of the pouch-shaped outer material may be bonded to each other by heat and pressure to seal the internal space of the outer material (140). That is, after the outer material (140) accommodates the electrode assembly (100) inside, the inner layer may be sealed by heat and pressure. Meanwhile, the metal layer may mainly be made of Al, STS, or the like, and the outer layer may be composed of a material having insulating properties.

[0045] The inner layer capable of sealing the outer material (140) through sealing may be made of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polyolefin resin such as polypropylene (PP) or polyethylene (PE) may be mainly used.

[0046] The secondary battery (10) may include an electrode lead (110). The electrode lead (110) may be electrically connected to the electrode assembly (100) and may be arranged to protrude outside the outer case (140). The secondary battery (10) may provide electrical energy to the outside by the electrode lead (110) protruding outside the outer case (140). Therefore, the electrode lead (110) may be a conductor.

[0047] The lead film (120) can cover the electrode lead (110) so that the outer material (140) and the electrode lead (110) are insulated from each other. Specifically, the lead film (120) can be placed on both sides of the electrode lead (110) to cover the electrode lead (110). The lead films (120) can be configured as a pair and placed on each side of the electrode lead (110).

[0048] In addition, the lead film (120) may be formed as a semi-permeable membrane that is impermeable to the electrolyte but permeable to the gas generated inside the outer material (140). In this case, the gas generated inside the outer material (140) may be discharged to the outside of the outer material (140) through the lead film (120), which is a semi-permeable membrane, via the aforementioned gas discharge path (S).

[0049] Specifically, when the internal pressure of the outer case (140) accommodating the electrode assembly (100) increases, the internal gas of the outer case (140) can flow into the gas discharge path (S) through the inner portion (d1) of the lead film (120) formed as a semi-permeable membrane and / or the microscopic empty space between the inner portion (d1) of the lead film (120) and the electrode lead (110). The gas flowing into the gas discharge path (S) can be discharged to the outside of the outer case (140) through the lead film (120), which is a semi-permeable membrane.

[0050] In addition, as the secondary battery (10) is repeatedly charged and discharged, when the internal pressure of the outer casing (140) increases, the inner portion (d1) of the lead film (120) may be pushed outward, and the gas discharge path (S) may be opened toward the inner space of the outer casing (140). In this case, the internal gas of the outer casing (140) may flow into the gas discharge path (S) through the open portion. The gas flowing into the gas discharge path (S) may be discharged to the outside of the outer casing (140) through the lead film (120), which is a semi-permeable membrane.

[0051] Meanwhile, as the secondary battery (10) is repeatedly charged and discharged, gas may be generated, which may increase the pressure inside the outer case (140). If the pressure inside the outer case (140) increases excessively, a venting phenomenon may occur, causing the secondary battery (10) to lose its function.

[0052] Specifically, an electrolyte may be accommodated together with an electrode assembly (100) inside the outer case (140) of the secondary battery (10). At this time, residual moisture of the electrolyte inside the outer case (140) of the secondary battery (10) or moisture that has penetrated from the outside may react with a lithium salt to generate HF, and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to decomposition of the electrolyte.

[0053] In addition, depending on the material of the positive electrode included in the electrode assembly (100) of the secondary battery (10), hydrogen and HF may be additionally generated, which may result in overheating due to overcharging and internal short circuit during the charging and discharging process. Accordingly, a large amount of gas may be generated inside the outer case (140). The pressure inside the outer case may increase due to such gas, and the increased pressure may cause a swelling phenomenon in which the outer case (140) swells or a venting phenomenon in which a portion of the outer case (140) bursts.

[0054] The secondary battery (10) according to the present invention may include a configuration capable of discharging gas inside the outer case (140) to the outside of the outer case (140) in order to prevent the venting phenomenon from occurring. Specifically, the secondary battery (10) may include a gas discharge induction unit (130) that forms a gas discharge path (S) through which gas inside the outer case (140) is discharged.

[0055] The gas discharge induction member (130) is a member interposed between the electrode lead (110) and the lead film (120), and one side of the gas discharge induction member (130) can be joined to the electrode lead (110). On the other hand, the other side of the gas discharge induction member (130) is not attached to the lead film (120), so a movement space through which gas can move can be formed between the gas discharge induction member (130) and the lead film (120). This movement space can be a gas discharge path (S) through which the internal gas of the outer material (140) is discharged.

[0056] In addition, the gap (d1) between one end of the lead film (120) of the secondary battery (10) adjacent to the electrode assembly (100) and the gas discharge induction part (130) may be formed narrower than the gap (d2) between the other end of the lead film (120) and the gas discharge induction part (130). Since the lead film (120) is bonded to the electrode lead (110), the bonding force between the outer part (d2) of the lead film (120) and the electrode lead (110) may be maintained stronger than the bonding force between the inner part (d1) of the lead film (120) and the electrode lead (110).

[0057] At this time, the lead film (120) may be configured as a semi-permeable membrane that does not allow the electrolyte to pass through but allows the gas to pass through. That is, when the internal pressure of the outer material (140) that accommodates the electrode assembly (100) increases, the internal gas of the outer material (140) can flow into the gas discharge path (S) through the inner portion (d1) of the lead film (120). Since the length of the inner portion (d1) of the lead film (120) is formed relatively short, the internal gas of the outer material (140) can easily flow into the gas discharge path (S) through the inner portion (d1) of the lead film (120).

[0058] In particular, as the internal pressure of the outer casing (140) increases due to repeated charging and discharging of the secondary battery (10), an outward pressure may be applied to the inner portion (d1) of the lead film (120). In this case, at least a portion of the inner portion (d1) of the lead film (120) may be pushed toward the gas discharge path (S). That is, the length of the region of the inner portion (d1) of the lead film (120) that is coupled to the electrode lead (110) may be shortened.

[0059] In addition, when the internal gas of the outer material (140) flows into the gas discharge path (S), a portion of the lead film (120) may be elongated. Specifically, a portion of the lead film (120) above the gas discharge path (S) is not bonded to the gas discharge induction unit (130), and thus its length may be elongated by the gas flowing into the gas discharge path (S). In other words, as the amount of gas flowing into the gas discharge path (S) increases, the overall volume of the gas discharge path (S) may increase.

[0060] At this time, as the amount of gas flowing into the gas discharge path (S) increases, the portion of the lead film (120) covering the gas discharge path (S) may be stretched. Taking Fig. 1 as an example, as the amount of gas flowing into the gas discharge path (S) increases, the portion of the lead discharge film (120) above the gas discharge path (S) may be stretched. Since the stretched portion of the lead discharge film (120) has a lower density than before being stretched, the speed at which internal gas is discharged through the stretched portion may be increased.

[0061] After the internal gas is sufficiently introduced into the gas discharge path (S), the internal gas can be discharged to the outside through the lead film (120) composed of a semi-permeable membrane. Therefore, the secondary battery (10) according to the present invention can discharge the internal gas of the outer packaging material (140) to the outside of the outer packaging material (140) when the internal pressure of the outer packaging material (140) increases.

[0062] The gas discharge path (S) is an empty space formed on the upper side of the gas discharge induction unit (130) and may have various shapes. For example, the shape of the gas discharge path (S) may correspond to the shape of the gas discharge induction unit (130).

[0063] The gas discharge induction unit (130) may include a first member (131) extending along the width direction of the electrode lead (110) and a second member (132) extending from one end of the first member (131) toward the internal space of the outer material (140). At this time, the width of the first member (131) may be formed to be larger than the width of the second member (132).

[0064] Here, when one second member (132) is connected to one end of the first member (131), the second member (132) may be connected to the center of the first member (131). In this case, the gas discharge induction unit (130) may have approximately the shape of the alphabet "T". At this time, the shape of the gas discharge path (S) may correspond to the shape of the gas discharge induction unit (130), and thus the gas discharge path (S) may also have the shape of the alphabet "T".

[0065] In addition, a plurality of second members (132) may be connected to one end of the first member (131). In this case, the gas discharge induction member (130) may have an approximate "ㅠ" shape. The shape of the gas discharge path (S) may correspond to the shape of the gas discharge induction member (130), and thus, the gas discharge path (S) may have a "ㅠ" shape.

[0066] Meanwhile, Fig. 4 is a drawing for explaining that a portion between the gas discharge induction part of the lead film and the internal space of the outer material is more weakly adhered to the electrode lead than other portions of the lead film. Fig. 4 illustrates that a portion (121) between the gas discharge induction part (130) of the lead film (120) and the internal space of the outer material (140) is more weakly adhered to the electrode lead (110) than other portions (122) of the lead film (120).

[0067] The portion of the lead film (120) facing the upper surface of the electrode lead (110) can be divided into three portions having different adhesive strengths. These may include a portion facing the gas discharge induction unit (130), a portion (121) between the gas discharge induction unit (130) and the internal space of the outer material (140), and other portions (122).

[0068] At this time, the part facing the gas discharge induction unit (130) can maintain a non-adhesive state with the gas discharge induction unit (130). In addition, the part (121) between the gas discharge induction unit (130) and the internal space of the outer material (140) can be opened when the internal pressure of the outer material (140) increases. When the part (121) between the gas discharge induction unit (130) and the internal space of the outer material (140) is opened, the internal gas of the outer material (140) can flow into the gas discharge path (S) through the opened part (121).

[0069] Finally, the remaining portion (122) must remain in an adhesive state even when the internal pressure of the outer shell (140) increases, so that it can be relatively strongly adhered to the electrode lead (110). In this case, even while gas is discharged through the remaining portion (122) composed of a semi-permeable membrane, a strong bond between the portion (122) and the electrode lead (110) can still be maintained.

[0070] That is, the lead film (120) of the secondary battery (10) according to the present invention can be adhered to the electrode lead (110) as described above, so that when the internal pressure of the outer material (140) increases, the gas generated inside the outer material (140) can be effectively discharged into the interior of the outer material (140).

[0071] Specifically, when the internal pressure of the outer material (140) increases, a portion (121) between the gas discharge induction part (130) of the lead film (120) and the internal space of the outer material (140) is detached from the electrode lead (110), and the internal space of the outer material (140) can be connected to the gas discharge path (S) above the gas discharge induction part (130). Thereafter, the internal gas of the outer material (140) can pass through the gas discharge path (S) and the outer portion (122) of the lead film (120), which is a semi-permeable membrane, to be discharged to the outside.

[0072] In addition, during the process of internal gas being discharged to the outside, a portion (122) corresponding to the outer boundary of the gas discharge induction portion (130) of the lead film (120) is strongly adhered to the electrode lead (110), and can thus be maintained in a state of being adhered to the electrode lead (110).

[0073] Meanwhile, Fig. 5 is a drawing for explaining that a portion between the second member (132) of the lead film and the internal space of the outer material is more weakly adhered to the electrode lead than other portions of the lead film. Fig. 5 illustrates that a portion (123) between the second member (132) of the lead film (120) and the internal space of the outer material (140) is more weakly adhered to the electrode lead (110) than other portions (124) of the lead film (120).

[0074] The portion of the lead film (120) facing the upper surface of the electrode lead (110) can be divided into three portions having different adhesive strengths. These may include a portion facing the gas discharge induction unit (130), a portion (123) between the second member (132) and the internal space of the outer material (140), and other portions (124).

[0075] At this time, the portion facing the gas discharge induction unit (130) can maintain a non-adhesive state with the gas discharge induction unit (130). In addition, the portion (123) between the second member (132) and the internal space of the outer material (140) must be opened when the internal pressure of the outer material (140) increases, and thus can maintain a weak adhesive state with the electrode lead (110). Finally, the remaining portion (124) must maintain an adhesive state even when the internal pressure of the outer material (140) increases, and thus can be relatively strongly adhered to the electrode lead (110).

[0076] That is, the lead film (120) of the secondary battery (10) according to the present invention can be adhered to the electrode lead (110) as described above, so that when the internal pressure of the outer material (140) increases, the gas generated inside the outer material (140) can be effectively discharged into the interior of the outer material (140).

[0077] Specifically, when the internal pressure of the outer casing (140) increases, a portion (123) between the second member (132) of the lead film (120) and the internal space of the outer casing (140) is detached from the electrode lead (110), and the internal space of the outer casing (140) can be communicated with the gas discharge path (S) on the upper side of the gas discharge induction unit (130). Thereafter, the internal gas of the outer casing (140) can pass through the gas discharge path (S) and the outer portion (124) of the lead film (120), which is a semi-permeable membrane, to be discharged to the outside.

[0078] During the process of internal gas being discharged to the outside, a portion (124) corresponding to the outer boundary of the gas discharge induction portion (130) of the lead film (120) is strongly adhered to the electrode lead (110), and can be maintained in a state of being adhered to the electrode lead (110).

[0079] Meanwhile, the gap (l1) between one end of the lead film (120) adjacent to the electrode assembly (100) and the second member (132) may be formed narrower than the gap (l2) between the other end of the lead film (120) and the first member (131). In this case, when the internal pressure of the outer material (140) increases, the bonding force between the outer portion (l2) of the lead film (120) and the electrode lead (110) may be maintained stronger than the bonding force between the inner portion (l1) of the lead film (120) and the electrode lead (110).

[0080] When the pressure in the internal space of the outer shell (140) accommodating the electrode assembly (100) increases, the internal gas of the outer shell (140) can flow into the gas discharge path (S) through the inner portion (l1) of the lead film (120) composed of a semi-permeable membrane. The internal gas flowing into the gas discharge path (S) can be discharged to the outside through the outer portion (l2) of the lead film (120).

[0081] Second Example

[0082] The secondary battery according to the second embodiment of the present invention differs from the first embodiment in that a gas absorption member is provided in the gas discharge path. The second embodiment will be described focusing on the differences, omitting any commonalities with the first embodiment as much as possible. It should be understood that any details not described in the second embodiment, if necessary, may be considered as those described in the first embodiment.

[0083] Fig. 6 is a drawing showing a gas absorption member provided in a gas discharge path, and Fig. 7 is a drawing showing a gas absorption member as a solid powder.

[0084] Referring to Fig. 6, a gas absorbing member (200) that absorbs internal gas may be provided in the gas discharge path (S). In this case, among the internal gases of the outer material (140), gas passing through the gas discharge path (S) is absorbed by the gas absorbing member (200), thereby lowering the internal pressure of the outer material (140), thereby providing the advantageous effect of preventing venting or damage to the outer material (140).

[0085] A gas absorbing member (200) is provided in the gas discharge path (S) and can absorb various types of internal gases. For example, the gas absorbing member (200) may include a carbon dioxide absorbent that absorbs carbon dioxide among the internal gases of the outer material (140). Such a carbon dioxide absorbent may include potassium carbonate or sodium carbonate.

[0086] In addition, the gas absorption member (200) is a dry absorption member provided in the gas discharge path (S) and may have various structures and shapes. In particular, the gas absorption member (200) may be a sheet-shaped member attached to the electrode lead (110).

[0087] Specifically, the gas absorbing member (200) is a sheet that is formed by putting a powdered carbon dioxide absorbent containing potassium carbonate and sodium carbonate into a mold and hardening it, and can be attached to the gas discharge member (130) located below the gas discharge path (S). In this case, even when the internal pressure of the outer material (140) increases, the gas absorbing member (200) is fixed in its position, thereby preventing the gas absorbing member (200) from flowing into the internal space of the outer material (140) and floating.

[0088] Referring to Fig. 7, the gas absorbing member (200) may be a solid powder containing potassium carbonate or sodium carbonate. Specifically, the gas absorbing member (200) may be a carbon dioxide absorbent containing potassium carbonate or sodium carbonate, and may be provided in powder form in the gas discharge path (S). In this case, the effective contact surface area between the gas absorbing member (200) and the internal gas of the outer material (140) can be maximized, thereby effectively absorbing the internal gas of the outer material (140).

[0089] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0090] [Explanation of symbols]

[0091] 10: Secondary battery 100: Electrode assembly

[0092] 110: Electrode lead 120: Lead film

[0093] 130: Gas discharge induction part 131: First member

[0094] 132: Second member 140: Exterior material

[0095] 141: Upper cladding 142: Lower cladding

[0096] 200: Gas absorption member S: Gas discharge path

Claims

1. An electrode assembly including an electrode and a separator; An outer material accommodating the above electrode assembly; An electrode lead connected to the electrode assembly and protruding outside the outer material; A lead film covering at least a portion of the electrode lead so that the electrode lead is insulated from the outer material; and It includes a gas discharge induction unit provided between the electrode lead and the lead film, and forming a gas discharge path through which internal gas of the outer material is discharged to the outside when the internal pressure of the outer material increases. A secondary battery characterized in that the gap between one end of the lead film adjacent to the electrode assembly and the gas discharge induction part is narrower than the gap between the other end of the lead film and the gas discharge induction part.

2. In claim 1, A secondary battery characterized in that the gas discharge path is formed between one surface of the gas discharge induction unit and the lead film.

3. In claim 2, A secondary battery characterized in that the shape of the gas discharge path corresponds to the shape of the gas discharge induction unit.

4. In claim 1, The first part of the lead film facing the gas discharge induction part maintains a non-adhesive state with the gas discharge induction part, A secondary battery characterized in that the second portion between the gas discharge induction portion of the lead film and the internal space of the outer material is more weakly bonded to the electrode lead than the remaining portion of the lead film excluding the first and second portions.

5. In claim 1, The above gas discharge induction unit, A first member extending along the width direction of the electrode lead; and A secondary battery characterized by including a second member extending from one end of the first member toward the inner space of the outer material.

6. In claim 5, A secondary battery, characterized in that the width of the first member is greater than the width of the second member.

7. In claim 6, A secondary battery characterized in that a plurality of second members are connected to one end of the first member.

8. In claim 5, The first part of the lead film facing the gas discharge induction part maintains a non-adhesive state with the gas discharge induction part, A secondary battery characterized in that a second portion between the second member of the lead film and the inner space of the outer material is more weakly adhered to the electrode lead than the remaining portion of the lead film excluding the first and second portions.

9. In claim 5, A secondary battery, characterized in that the gap between one end of the lead film adjacent to the electrode assembly and the second member is narrower than the gap between the other end of the lead film and the first member.

10. In claim 1, A secondary battery characterized in that a gas absorbing member for absorbing the internal gas is provided in the gas discharge path.

11. In claim 10, The above gas absorbing member is, A secondary battery characterized by including a carbon dioxide absorbent that absorbs carbon dioxide among the internal gases.

12. In claim 10, A secondary battery characterized in that the gas absorbing member is a solid powder containing potassium carbonate or sodium carbonate.

13. In claim 10, A secondary battery characterized in that the gas absorbing member is a sheet-shaped member attached to the gas discharging member and contains potassium carbonate or sodium carbonate.

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