Secondary battery having venting portion, battery module and battery pack including the same

Abstract

The present invention relates to a secondary battery including a venting portion, a battery module including the same, and a battery pack. When the secondary battery expands due to abnormal behavior, the first and second members of the venting portion are separated from the venting hole of the pouch case, thereby opening the venting hole and improving safety.

Description

Technology Field

[0001] The present invention relates to a secondary battery including a venting portion, a battery module including the same, and a battery pack. Background Technology

[0003] With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, much research is being conducted on lithium secondary batteries, which possess high energy density and discharge voltage, and they are also being commercialized and widely used.

[0004] Among various types of rechargeable batteries, lithium-ion batteries are becoming widely used due to their high operating voltage and high energy density per unit weight. Lithium-ion batteries are manufactured in various shapes, with representative types including cylindrical, can, and pouch types.

[0005] A lithium secondary battery largely comprises an electrode assembly including a positive electrode, a negative electrode, and a separator, and an electrolyte that interacts with the electrode assembly. The above charging and discharging are achieved through the interaction between this electrode assembly and the electrolyte.

[0006] In such secondary batteries, the internal temperature may rise or the internal gas pressure may become excessively high due to overcharging, over-discharging, internal short circuits, or other overheating conditions. This causes a swelling phenomenon in which the secondary battery bulges.

[0007] Meanwhile, if such swelling of the secondary battery occurs continuously, deformation of the secondary battery may occur, and local deformation of the battery module or battery pack may occur during this process. However, if deformation of the battery module or battery pack occurs as described above, problems such as fire may arise due to interference between the battery cells.

[0008] Therefore, there is a need to develop technology for secondary batteries capable of addressing the swelling phenomenon, as well as battery modules and battery packs containing such batteries. Prior art literature

[0010] Republic of Korea Published Patent No. 10-2006-0091788 The problem to be solved

[0011] The present invention aims to solve the above-mentioned problems by providing a secondary battery including a venting portion to cope with the swelling phenomenon of the secondary battery, a battery module including the same, and a battery pack. means of solving the problem

[0013] The present invention relates to a secondary battery comprising a venting portion. In one example, the secondary battery according to the present invention comprises: an electrode assembly; a pouch case that accommodates the electrode assembly and has at least one venting hole formed therein for discharging internal gas; and a venting portion coupled to the venting hole of the pouch case to open the venting hole when the pouch case expands.

[0014] In a specific example, the venting portion may include first and second members that are joined together by compressing both sides with a pouch case in between, but are separated when the pouch case expands.

[0015] In one example, the first member includes a fastening pin penetrating a venting hole, and the second member may have a structure in which a fastening groove or a fastening hole is formed to which the fastening pin is fastened.

[0016] At this time, the above-mentioned fastening pin may further include a tube-shaped sealing member that wraps around the outer surface.

[0017] In addition, the sealing member may include one or more materials selected from flexible or elastic synthetic resins, silicone, and rubber.

[0018] In addition, the above-mentioned fastening pin may be one or more materials selected from the group consisting of metal, fiber-reinforced metal, polymer, ceramic, metal coated with polymer, and fiber-reinforced plastic.

[0019] In another example, the second member may have a structure in which a fastening hole is formed to which a fastening pin is fastened, and the fastening pin may have a structure in which a fixing projection is formed at its end to engage with the fastening hole.

[0020] At this time, the first and second members may include one or more materials selected from a flexible or elastic synthetic resin, silicone, and rubber.

[0021] Furthermore, in the secondary battery according to the present invention, the first and second members may each have a structure having a contact surface that covers the venting hole of the pouch case.

[0022] Meanwhile, the above pouch case has a structure in which a terrace area is formed that surrounds a part of the electrode lead connected to the electrode assembly, and the venting hole may be formed in the terrace area.

[0023] In addition, the above secondary battery may be a lithium secondary battery.

[0025] In addition, the present invention provides a battery module including the secondary battery described above.

[0027] Furthermore, the present invention provides a battery pack comprising the battery module described above.

[0028] In a specific example, the above battery pack can be used as a power source for medium to large devices. Effects of the invention

[0030] According to the secondary battery including the venting portion of the present invention, when the secondary battery expands due to abnormal behavior, the first and second members of the venting portion are separated from the venting hole of the pouch case, thereby opening the venting hole.

[0031] Accordingly, the present invention can provide a secondary battery with improved safety, a battery module including the same, and a battery pack. Brief explanation of the drawing

[0033] FIG. 1 is a plan view of a secondary battery including a venting portion according to the present invention. FIG. 2 is a left side view of a secondary battery including a venting portion according to the present invention. FIGS. 3 and 4 are detailed drawings of a secondary battery including a venting portion according to the present invention. FIGS. 5 and 6 are conceptual diagrams for explaining the operation of the vent portion when swelling occurs in a secondary battery according to the present invention. FIG. 7 is a detailed diagram of a secondary battery including a venting portion according to the present invention. FIG. 8 is a detailed view of a secondary battery including a venting portion according to the present invention. FIG. 9 is a schematic diagram of a battery module according to the present invention. Specific details for implementing the invention

[0034] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail in the detailed description.

[0035] However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0036] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0037] Furthermore, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "immediately above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "immediately below" the other part, but also cases where there is another part in between. Additionally, in the present application, being "placed on" may include cases where it is placed on the lower part as well as on the upper part.

[0038] In the present invention, "secondary battery" refers to a battery cell and may be a pouch-type secondary battery having a structure in which an electrode assembly having a positive / separator / negative electrode structure is embedded in a laminate sheet outer material in a state connected to electrode leads formed on the outside of the outer material. In addition, the electrode leads may be structured to be drawn out to the outside of the sheet and extended in the same direction or opposite directions.

[0039] In the present invention, the term "venting part" refers to a part coupled to a pouch case, which is intended to form a vent in the pouch case when the pouch case of a secondary battery swells due to swelling. Specifically, the venting part is coupled to a venting hole of the pouch case and is intended to be separated from the pouch case to open the venting hole when the secondary battery expands due to abnormal behavior.

[0041] Hereinafter, a secondary battery including a venting portion including an insulating coating portion according to the present invention, a battery module including the same, and a battery pack including the same will be described in detail with reference to the drawings.

[0043] [First embodiment]

[0044] The present invention provides a secondary battery including a venting portion as a first embodiment.

[0046] secondary battery

[0047] FIG. 1 is a plan view of a secondary battery including a venting portion according to the present invention, FIG. 2 is a left side view of a secondary battery including a venting portion according to the present invention, and FIG. 3 to 4 are detailed views of a secondary battery including a venting portion according to the present invention.

[0048] Referring to FIGS. 1 to 4, a secondary battery (100) according to the present invention comprises an electrode assembly (not shown), a pouch case (110) that accommodates the electrode assembly, and a venting part (120) coupled to the pouch case (110).

[0049] The above electrode assembly has a structure comprising an anode having an anode composite layer formed on the surface of an anode current collector, a cathode having a cathode composite layer formed on the surface of a cathode current collector, and a separator positioned between the anode and the cathode to insulate the anode and the cathode, and can be wound into a stack type, a stack folding type, or a jelly-roll shape and accommodated in the pouch case (110).

[0050] Meanwhile, the electrode assembly may be structured to be embedded in a state connected to first and second electrode leads (112, 113) formed outside the pouch case (110). Specifically, the first and second electrode leads (112, 113) may be formed to extend from the inside to the outside of the pouch case (110). For example, the first electrode lead (112) may be electrically connected to a positive or negative electrode, and the second electrode lead (113) may be electrically connected to a positive or negative electrode, but may have an electrically opposite polarity to the first electrode lead (112).

[0051] Meanwhile, the first and second electrode leads (112, 113) are drawn out to the outside of the pouch case (110) and may have a structure extending in the same direction or in opposite directions. In the drawing, the first and second electrode leads (112, 113) are shown as having a structure extending in opposite directions, but are not limited thereto.

[0052] The above pouch case (110) may be made of a commonly used aluminum laminate sheet and may provide a space capable of accommodating the electrode assembly. At this time, the pouch case (110) may have a structure in which at least one venting hole (111) is formed for venting internal gas. In a specific example, the pouch case (110) may have a structure in which a terrace area (1110) is formed that surrounds a part of the electrode lead (112, 113) connected to the electrode assembly, and the venting hole (111) may be formed in the terrace area (1110) of the pouch case (110).

[0053] Generally, in a secondary battery (100), the terrace area (1110) refers to the space between each electrode lead (112, 113) and the area where the electrode assembly is accommodated. In particular, the terrace area (1110) may be the area where the change in pressure occurs most significantly and rapidly among the entire area of ​​the secondary battery (100). Accordingly, it is preferable that the venting hole (111) be formed in the terrace area (1110) of the pouch case (110).

[0054] The venting hole (111) is for discharging internal gas of the pouch case (110) and may be a structure formed in one or more places in the pouch case (110). Although the venting hole (111) is shown as including two in the drawing, it is not limited thereto.

[0055] Meanwhile, a venting part (120) may be coupled to the venting hole (111) of the pouch case (110). In a specific example, the venting part (120) is intended to open the venting hole (111) when the pouch case (110) expands, and may include first and second members (121, 122) that are joined together by compressing both sides with the pouch case (110) in between. The first and second members (121, 122) are joined together by compressing both sides with the pouch case (110) in between, and can be separated from each other when the pouch case (110) expands to open the venting hole (111).

[0056] Conventionally, a technology including a pin directed toward the terrace area (1110) was developed to form a hole in the terrace area (1110) when the secondary battery (100) expands. However, since the end of the pin is directed toward the terrace area (1110), there was a problem such as forming a hole in the secondary battery (100) due to interference from the pin when the secondary battery moves or when the secondary battery does not expand sufficiently. Accordingly, the present invention can solve the above-mentioned problem by forming a vent hole (111) in the secondary battery (100), attaching a venting part (120) to the vent hole (111), and designing the venting hole to open when the pouch case (110) expands.

[0057] As previously explained, the terrace area (1110) of the secondary battery (100) is the area that swells the most when swelling occurs. Due to the expansion of the pouch case (110), the gap between the first and second members (121, 122) of the venting section (120) widens, allowing them to be separated from each other. Accordingly, the venting section (120) is removed from the venting hole (111), and the venting hole (111) can be opened. In addition, the secondary battery (100) according to the present invention has the venting hole (111) opened, allowing gas inside the pouch case (110) to be discharged to the outside through the venting hole (111).

[0058] Meanwhile, the first and second members (121, 122) can be joined together by pressing both sides with the pouch case (110) in between to close the venting hole (111). In a specific example, the first and second members (121, 122) may have a contact surface that covers the venting hole (111).

[0059] In one example, the first and second members (121, 122) may be in the form of blocks, and the first member (121) may include a fastening pin (1211) that penetrates the venting hole (111). Additionally, the second member (122) may be a structure in which a fastening groove or fastening hole (1222) corresponding to the fastening pin (1211) is formed. For example, the second member (122) may be a structure in which a fastening groove (1222) corresponding to the fastening pin (1211) is formed.

[0060] Since the first and second members (121, 122) must be separated from each other when the pouch case (110) is expanded, the length of the fastening pin (1211) of the first member (121) may be shorter than the height of the secondary battery (100) when the pouch case (110) is expanded.

[0061] In addition, the above-mentioned fastening pin (1211) may be made of one or more materials selected from the group consisting of metal, fiber-reinforced metal, polymer, ceramic, metal coated with polymer, and fiber-reinforced plastic.

[0062] The above polymer may be one or more selected from the group consisting of, for example, heat-resistant plastic, aramid fiber, carbon fiber, nylon, polyethylene, polypropylene, and polyethylene terephthalate, and the above metal may be one or more selected from the group consisting of aluminum, nickel, iron, tungsten, titanium, titanium, and cobalt, but is not limited thereto.

[0063] In addition, the materials of the first and second members (121, 122) are not specifically limited and may include various materials, for example, materials such as polymer resin.

[0064] Furthermore, the secondary battery according to the present invention may be a lithium secondary battery. In a specific example, the lithium secondary battery comprises an electrode assembly including a positive electrode, a negative electrode, and a separator, and an electrolyte that interacts with the electrode assembly. Through the interaction between the electrode assembly and the electrolyte, the above charging and discharging may be performed, and the internal temperature of the battery may rise or the gas pressure inside the battery may become excessively high due to overcharging and overdischarging, internal short circuits, or other overheating conditions.

[0065] Accordingly, the present invention is intended to separate the first and second members from the venting hole of the pouch case and open the venting hole when the lithium secondary battery expands due to the continuous occurrence of a swelling phenomenon in which the lithium secondary battery swells.

[0067] Operating mechanism of the venting section

[0068] FIGS. 5 and 6 are conceptual diagrams for explaining the operation of the vent portion when swelling occurs in a secondary battery according to the present invention. Referring to FIGS. 5 and 6, the secondary battery (100) according to the present invention has a structure in which an electrode assembly (101) in which a positive electrode, a negative electrode, and a separator are stacked inside a pouch case (110) is included, so when swelling occurs, the terrace area (1110) swells the most.

[0069] The terrace area (1110) of the above pouch case (110) may swell above a certain level, thereby allowing the first and second members (121, 122) of the venting section (120) that are compressing both sides of the pouch case (110) to be spaced apart. For reference, the first member (121) may be placed on the upper surface of the terrace area (1110) and the second member (122) may be placed on the lower surface of the terrace area (1110) so as to be combined to compress both sides of the pouch case (110), and the first and second members (121, 122) may be separated from each other by the expansion of the pouch case (110).

[0070] The first and second members (121, 122) of the venting section (120) can be removed from the venting hole (111) so that the venting hole (111) can be opened. And, in the secondary battery (100) according to the present invention, the venting hole (111) can be opened so that gas inside the pouch case (110) can be discharged to the outside through the venting hole (111).

[0071] A secondary battery (100) including a venting portion (120) according to the present invention can open the venting hole (111) when expanded to relieve overpressure inside the pouch case (110) and improve safety.

[0073] [Second embodiment]

[0074] The present invention provides a secondary battery including a venting portion as a second embodiment.

[0076] secondary battery

[0077] FIG. 7 is a detailed view of a secondary battery including a venting portion according to the present invention. Referring to FIG. 7, the secondary battery (200) according to the present invention comprises an electrode assembly (not shown), a pouch case (210) that accommodates the electrode assembly, and a venting portion (220) coupled to the pouch case (210).

[0078] The pouch case (210) of the secondary battery (200) according to the present invention may have a structure in which a venting hole (211) is formed, and the venting portion (220) may be coupled to the venting hole (211). In a specific example, the venting portion (220) is intended to open the venting hole (211) when the pouch case (210) expands, and may include first and second members (221, 222) that are joined together by compressing both sides with the pouch case (210) in between. The first and second members (221, 222) are joined together by compressing both sides with the pouch case (210) in between, and can be separated from each other when the pouch case (210) expands to open the venting hole (211).

[0079] Meanwhile, the first and second members (221, 222) may be in the form of blocks, and the first member (221) may include a fastening pin (2211) that penetrates the venting hole (211). Additionally, the second member (222) may have a structure in which a fastening hole (2222) corresponding to the fastening pin (2211) is formed. Furthermore, the end of the fastening pin (2211) of the first member (221) may have a structure in which a fixing projection (2212) is formed to engage with the fastening hole (2222) of the second member (222).

[0080] Since the first and second members (221, 222) must be separated from each other when the pouch case (210) is expanded, the length of the fastening pin (2211) of the first member (221) may be shorter than the height of the secondary battery (200) when the pouch case (210) is expanded.

[0081] In addition, the first and second members (221, 222) may include one or more materials selected from flexible or elastic synthetic resin, silicone, and rubber. Likewise, the fastening pin (2211) may also include one or more materials selected from flexible or elastic synthetic resin, silicone, and rubber. For example, the first and second members (221, 222) may be made of silicone.

[0082] The secondary battery (200) of the configuration described above can open the venting hole (211) when expanded to relieve overpressure inside the pouch case (210) and improve safety.

[0084] [Third Embodiment]

[0085] The present invention provides a secondary battery including a venting portion as a third embodiment.

[0087] secondary battery

[0088] FIG. 8 is a detailed view of a secondary battery including a venting portion according to the present invention. Referring to FIG. 8, the secondary battery (300) according to the present invention comprises an electrode assembly (not shown), a pouch case (310) that accommodates the electrode assembly, and a venting portion (320) coupled to the pouch case (310).

[0089] The pouch case (310) of the secondary battery (300) according to the present invention may have a structure in which a venting hole (311) is formed, and the venting portion (320) may be coupled to the venting hole (311). In a specific example, the venting portion (320) is intended to open the venting hole (311) when the pouch case (310) expands, and may include first and second members (321, 322) which are joined together by compressing both sides with the pouch case (310) in between. The first and second members (321, 322) are joined together by compressing both sides with the pouch case (310) in between, and when the pouch case (310) expands, they separate from each other to open the venting hole (311).

[0090] In a specific example, the first and second members (321, 322) may be in the form of blocks, and the first member (321) may include a fastening pin (3211) that penetrates the venting hole (311). Additionally, the second member (322) may have a structure in which a fastening groove or a fastening hole (3222) corresponding to the fastening pin (3211) is formed. For example, the second member (322) may have a structure in which a fastening groove (3222) corresponding to the fastening pin (3211) is formed.

[0091] At this time, the fastening pin (3211) of the first member (321) may further include a tube-shaped sealing member (3213) that surrounds the outer surface. The sealing member (3213) is intended to prevent leakage of electrolyte or gas inside the pouch case (310) when the first and second members (321, 322) are coupled to the venting hole (311) of the pouch case (310).

[0092] In addition, the sealing member (3213) may include one or more materials selected from a flexible or elastic synthetic resin, silicone, and rubber. The sealing member (3213) may be silicone, but is not limited thereto.

[0093] Furthermore, the sealing member (3213) can prevent secondary risks such as short circuits from occurring when the fastening pin (3211) is made of metal and the fastening pin (3211) passes through the venting hole (311) and comes into contact with the electrodes inside the secondary battery.

[0094] The secondary battery (300) of the configuration described above can open the venting hole (311) when expanded to relieve overpressure inside the pouch case (310) and improve safety.

[0096] [Fourth embodiment]

[0097] The present invention provides a battery module and a battery pack including the secondary battery described above as a fourth embodiment.

[0099] Battery modules and battery packs

[0100] FIG. 9 is a schematic diagram of a battery module according to the present invention. Referring to FIG. 9, the present invention provides a battery module (401) comprising the secondary battery (400) described above. In addition, the present invention provides a battery pack (not shown) comprising the battery module (401).

[0102] In a specific example, the secondary battery (400) according to the present invention may be used in a high-output, high-capacity battery requiring a long lifespan and excellent durability, or in a battery module or battery pack comprising a plurality of such batteries as unit cells.

[0103] Meanwhile, since multiple secondary batteries (400) are stacked together within the battery module (401) or battery pack, a venting hole (not shown) may be included in a terrace area that swells outward relatively during swelling, and a venting portion (420) may be included in the venting hole.

[0104] The above secondary battery (400) can open the venting hole when expanded to relieve overpressure inside the pouch case (410) and improve safety. Since the configuration of the venting part (420) has been described above, the specific configuration and operating mechanism will be omitted.

[0105] In addition, the above battery pack can be used as a power source for medium-to-large devices requiring high temperature stability, long cycle characteristics, and high rate characteristics. Specific examples of such medium-to-large devices include power tools that are powered by an electric motor; electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; electric trucks; electric commercial vehicles; or power storage systems.

[0106] The structure and manufacturing method of such medium-to-large battery modules or medium-to-large battery packs are known in the art, so a detailed description thereof will be omitted.

[0108] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0110] 100, 200, 300, 400: Secondary battery 101: Electrode assembly 110, 210, 310, 410: Pouch Case 1110, 2110, 3110: Terrace area 111, 211, 311: Benting Hall 112, 212, 312: First electrode leads 113, 213, 313: Second electrode leads 120, 220, 320, 420: Venting section 121, 221, 321: First part 1211, 2211, 3211: Fastening pins 2212: Fixed protrusion 3213: Sealing component 122, 222, 322: Second absence 1222, 3222: Fastening groove, fastening hole 2222: Fastening hole 401: Battery Module

Claims

Claim 1 A secondary battery comprising: an electrode assembly; a pouch case that accommodates the electrode assembly and has at least one venting hole formed therein for internal gas discharge; and a venting portion coupled to the venting hole of the pouch case and opening the venting hole when the pouch case expands, wherein the venting portion comprises first and second members that are joined together by compressing both sides with the pouch case in between, but are separated when the pouch case expands, wherein the first member includes a fastening pin that penetrates the venting hole, and the second member has a structure formed therein in a fastening groove or a fastening hole into which the fastening pin is fastened. Claim 2 delete Claim 3 A secondary battery according to claim 1, wherein the fastening pin further comprises a tube-shaped sealing member that surrounds the outer surface. Claim 4 A secondary battery according to claim 3, wherein the sealing member comprises one or more materials selected from a flexible or elastic synthetic resin, silicone, and rubber. Claim 5 A secondary battery according to claim 1, wherein the fastening pin is made of one or more materials selected from the group consisting of metal, fiber-reinforced metal, polymer, ceramic, metal coated with a polymer, and fiber-reinforced plastic. Claim 6 A secondary battery according to claim 1, wherein the second member has a structure in which a fastening hole is formed to which a fastening pin is fastened, and the fastening pin has a structure in which a fixing projection is formed at the end to act as a catch in the fastening hole. Claim 7 A secondary battery according to claim 6, wherein the first and second members comprise one or more materials selected from a flexible or elastic synthetic resin, silicone, and rubber. Claim 8 In claim 1, the first and second members are each a secondary battery having a structure having a contact surface that covers a venting hole of a pouch case. Claim 9 A secondary battery according to claim 1, wherein the pouch case has a structure in which a terrace area is formed that surrounds a part of an electrode lead connected to an electrode assembly, and the venting hole is formed in the terrace area. Claim 10 In claim 1, the secondary battery is characterized as being a lithium secondary battery. Claim 11 A battery module including a secondary battery according to claim 1. Claim 12 A battery pack comprising a battery module according to claim 11. Claim 13 In Clause 12, the battery pack is a battery pack used as a power source for medium to large devices.

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