Cylindrical battery cell, battery pack and vehicle including same, and current collector plate

Abstract

A cylindrical battery cell, a battery pack and a vehicle including same, and a current collector plate are disclosed. The cylindrical battery cell according to one embodiment of the present invention comprises: an electrode assembly structured such that a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction; a cylindrical battery can in which the electrode assembly is accommodated and which has a through hole; a positive electrode current collector plate electrically connected to the positive electrode plate; a cell terminal connected to the positive electrode current collector plate through the through hole of the battery can; and a negative electrode current collector plate electrically connected to the negative electrode plate, wherein the positive electrode current collector plate or the negative electrode current collector plate has a fracture-inducing portion so that at least a portion of the positive electrode current collector plate or the negative electrode current collector plate is fractured by gas generated in the battery can.

Description

Cylindrical battery cells and battery packs and vehicles including the same and current collectors

[0001] This application claims priority to Korean Patent Application No. 10-2023-0099233, filed on July 28, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0002] The present invention relates to a cylindrical battery cell, a battery pack and a vehicle including the same, and a current collector, and more specifically, to a cylindrical battery cell capable of reducing the internal pressure of the cylindrical battery cell, a battery pack and a vehicle including the same, and a current collector.

[0003] Secondary batteries, which have high applicability according to product group and electrical characteristics such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electrical power sources.

[0004] These secondary batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency because they not only have the primary advantage of drastically reducing the use of fossil fuels, but also have the advantage of producing no byproducts from energy use.

[0005] Commonly used secondary battery types include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells ranges from approximately 2.5 V to 4.5 V.

[0006] Therefore, when a higher output voltage is required, multiple battery cells are connected in series to form a battery module or battery pack. Furthermore, depending on the required charge / discharge capacity, a number of battery cells are connected in parallel to form a battery module or battery pack. Accordingly, the number and electrical connection configuration of battery cells included in a battery module or battery pack can be varied depending on at least one of the required output voltage and charge / discharge capacity.

[0007] Meanwhile, known secondary battery cell types include cylindrical, prismatic, and pouch-shaped battery cells. Cylindrical battery cells are constructed by interposing a separator, which serves as an insulator, between the positive and negative plates, winding the separator to form a jelly-roll-shaped electrode assembly. This assembly, along with an electrolyte, is then inserted into a battery can to form the battery. Furthermore, cylindrical battery cells may use current collectors to electrically connect the positive and negative plates.

[0008] Cylindrical battery cells have an increased internal pressure due to gas generation inside the electrode assembly as a result of repeated charge and discharge cycles. If this internal pressure is not reduced, an explosion may occur. Therefore, venting parts can be formed in various ways in cylindrical battery cells.

[0009] However, in the case of conventional cylindrical battery cells, there is a problem in that gas discharge is not easy because the current collector blocks the space between the center of the electrode assembly and the venting part.

[0010] Accordingly, the technical problem to be solved by the present invention is to provide a cylindrical battery cell, a battery pack and a vehicle including the same, and a collector plate capable of reducing the internal pressure and thereby preventing an explosion when gas is generated inside the cylindrical battery cell and the internal pressure increases by changing the shape of the collector plate.

[0011] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0012] According to one aspect of the present invention, a cylindrical battery cell can be provided, comprising: an electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction; a cylindrical battery can in which the electrode assembly is accommodated and a through hole is formed; a positive electrode current collector electrically connected to the positive electrode plate; a cell terminal connected to the positive electrode current collector through the through hole of the battery can; and a negative electrode current collector electrically connected to the negative electrode plate, wherein a break-inducing portion is formed on the positive electrode current collector plate or the negative electrode current collector plate so that at least a portion of the positive electrode current collector plate or the negative electrode current collector plate is broken by gas generated inside the battery can.

[0013] In one embodiment, the positive electrode collector plate or the negative electrode collector plate may include a frame portion defining a frame; a central portion spaced from the frame portion and coupled to the electrode assembly; and a connecting portion connecting the frame portion and the central portion.

[0014] In one embodiment, the fracture-inducing portion may be formed in the connecting portion.

[0015] In one embodiment, the fracture-inducing portion may be formed in the connecting portion at a point where the central portion and the connecting portion meet.

[0016] In one embodiment, the fracture inducing portion may be formed as a notching groove.

[0017] In one embodiment, the fracture inducing portion may be formed as a through hole.

[0018] In one embodiment, the number of connecting portions is four, and the notching grooves can be formed in pairs, one for each connecting portion, for a total of eight.

[0019] In one embodiment, the notching groove may be formed toward the inside of the connecting portion in a direction that gradually or continuously reduces the width or thickness of the connecting portion.

[0020] In one embodiment, the fracture-inducing portion may be configured to include a twist portion formed by twisting the connecting portion.

[0021] In one embodiment, the twisted portion may include a first portion connected to the central portion; and a second portion twisted and folded from the first portion and then joined to the edge portion.

[0022] In one embodiment, the twist portion may be formed into a curved shape so as to rotate the gas.

[0023] In one embodiment, the twist portion may be configured such that the connecting portion rotates 180 degrees from the center and is joined to the edge portion.

[0024] Meanwhile, according to another aspect of the present invention, a battery pack including at least one cylindrical battery cell as described above may be provided, and further, a vehicle including at least one cylindrical battery cell as described above may be provided.

[0025] Meanwhile, according to another aspect of the present invention, a current collector plate for electrically connecting an electrode assembly located at a portion where a venting portion is formed in a cylindrical battery cell may be provided, the current collector plate including a rim portion defining a rim; a center portion spaced apart from the rim portion and coupled to the electrode assembly; and a connecting portion connecting the rim portion and the center portion, wherein a break-inducing portion is formed on the current collector plate so that at least a portion of the current collector plate is broken by a gas generated in the cylindrical battery cell.

[0026] Embodiments of the present invention have the effect of reducing the internal pressure by changing the shape of the current collector plate when gas is generated inside the cylindrical battery cell and the internal pressure increases.

[0027] Additionally, it has the effect of preventing explosion of cylindrical battery cells.

[0028] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0030] FIG. 1 is a perspective view of a cylindrical battery cell according to one embodiment of the present invention.

[0031] FIG. 2 is a cross-sectional view of a cylindrical battery cell according to one embodiment of the present invention.

[0032] FIG. 3 is a drawing illustrating a battery can in a cylindrical battery cell according to one embodiment of the present invention.

[0033] FIG. 4 is a perspective view of a negative electrode collector plate of a cylindrical battery cell according to one embodiment of the present invention.

[0034] FIGS. 5 to 10 are each a perspective view of a negative electrode collector plate according to a modified embodiment of FIG. 4.

[0035] Fig. 11 is a perspective view showing a deformed shape of the negative electrode collector plate of Fig. 10.

[0036] FIG. 12 is a schematic drawing showing the configuration of a battery pack including a cylindrical battery cell according to each embodiment of the present invention.

[0037] FIG. 13 is a drawing for explaining a vehicle including a battery pack according to each embodiment of the present invention.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Terms or words used in this specification and claims should not be interpreted as limited to their conventional or dictionary meanings, but should be interpreted with 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 best explain his or her own invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention, and various equivalents and modified examples may exist as of the time of this application.

[0039] In the drawings, the sizes of each component or specific parts of that component are exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect its actual size. If a detailed description of a related known function or configuration is deemed to unnecessarily obscure the gist of the present invention, such description will be omitted.

[0040] The term 'joint' or 'connection' as used herein includes not only cases where one member is directly joined or directly connected to another member, but also cases where one member is indirectly joined or indirectly connected to another member through a connecting member.

[0041] FIG. 1 is a perspective view of a cylindrical battery cell according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present invention, FIG. 3 is a drawing illustrating a battery can in a cylindrical battery cell according to an embodiment of the present invention, and FIG. 4 is a perspective view of a negative electrode collector plate of a cylindrical battery cell according to an embodiment of the present invention.

[0042] Referring to FIGS. 1 and 2, a cylindrical battery cell (10) according to one embodiment of the present invention includes an electrode assembly (100), a battery can (200), a positive electrode collector plate (300), a cell terminal (400), and a negative electrode collector plate (600).

[0043] Referring to FIG. 2, the electrode assembly (100) has a structure in which a positive electrode plate (110), a negative electrode plate (120), and a separator (130) interposed between the positive electrode plate (110) and the negative electrode plate (120) are wound in one direction. In addition, a central hole (140) is formed in the center of the electrode assembly (100), and can be formed in a jelly roll type.

[0044] For example, the electrode assembly (100) can be manufactured by winding a laminate formed by sequentially stacking a negative electrode plate (120), a separator (130), a positive electrode plate (110), and a separator (130) at least once. Here, the positive electrode plate (110) and the negative electrode plate (120) can be formed in a sheet shape.

[0045] That is, the electrode assembly (100) applied to the present embodiment may be a coiled type electrode assembly (100). In this case, an additional separator may be provided on the outer circumferential surface of the electrode assembly (100) for insulation from the battery can (200). That is, the electrode assembly (100) may have a coiled structure well known in the related technical field without limitation.

[0046] A positive electrode plate (110) may have a positive electrode active material applied to one or both sides, and a first non-coated portion (111, see FIG. 2) on which the positive electrode active material is not applied may be formed at an end of the positive electrode plate (110). Although FIG. 2 illustrates a positive electrode plate (110) on which a first non-coated portion (111) is formed, a cylindrical battery cell (10) according to an embodiment of the present invention includes an embodiment of a positive electrode plate (110) on which a first non-coated portion (111) is not formed. However, for convenience of explanation, the following description will focus on a case where a first non-coated portion (111) is formed on the positive electrode plate (110). The first non-coated portion (111) may be exposed to the outside of the separator (130) while forming a plurality of winding turns based on the center of the electrode assembly (100), and may be used as an electrode tab in itself.

[0047] The negative electrode plate (120) may have a negative active material applied to one or both sides, and a second non-coated portion (121, see FIG. 2) on which the negative active material is not applied may be formed at an end of the negative electrode plate (120). Although FIG. 2 illustrates a negative electrode plate (120) on which a second non-coated portion (121) is formed, the cylindrical battery cell (10) according to an embodiment of the present invention includes an embodiment of a negative electrode plate (120) on which a second non-coated portion (121) is not formed. However, for convenience of explanation, the following description will focus on a case where the second non-coated portion (121) is formed on the negative electrode plate (120). The second non-coated portion (121) may be exposed to the outside of the separator (130) while forming a plurality of winding turns based on the center of the electrode assembly (100), and may be used as an electrode tab in itself.

[0048] That is, at least one of the positive electrode plate (110) and the negative electrode plate (120) may each include a non-coated portion in which the active material is not coated on the long side in the winding direction. In addition, the first non-coated portion (111) and the second non-coated portion (121) may be configured to face in opposite directions.

[0049] Here, the positive electrode active material coated on the positive electrode plate (110) and the negative electrode active material coated on the negative electrode plate (120) can be used without limitation as long as they are active materials known in the art.

[0050] In addition, the separation membrane (130) may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., which may be used alone or in a laminated manner.

[0051] As another example, the separator (130) may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0052] At least one surface of the separator (130) may include a coating layer of inorganic particles. Furthermore, the separator (130) itself may be formed of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are combined with a binder such that an interstitial volume exists between adjacent particles.

[0053] In addition, the center hole (140) of the electrode assembly (100) is also used for welding the cell terminal (400) (positive terminal) and the positive current collector (300). That is, the electrode assembly (100) can be configured to weld the cell terminal (400) and the positive current collector (300) by irradiating a laser through the center hole (140).

[0054] Referring to Fig. 2, an electrode assembly (100) is housed in a battery can (200). And, referring to Fig. 3, a through hole (211) is formed in the battery can (200). For example, the battery can (200) is formed in a cylindrical shape, and the electrode assembly (100) is housed inside the battery can (200) and can be electrically connected to the negative electrode plate (120) of the electrode assembly (100). Accordingly, the battery can (200) can have the same polarity as the negative electrode plate (120), i.e., a negative electrode.

[0055] Here, the diameter of the battery can (200) is formed to be larger than the diameter of the electrode assembly (100). A gap of a preset size is formed between the battery can (200) and the positive electrode collector plate (300), and an insulator (500) may be interposed between the gap.

[0056] If the size of the electrode assembly (100) is increased while the size of the battery can (200) is determined according to the standard, the total capacity of the battery cell increases, but the gap between the battery can (200) and the electrode assembly (100) decreases.

[0057] That is, when the size of the electrode assembly (100) is increased to increase the overall capacity of the battery cell, the gap between the battery can (200) and the electrode assembly (100) decreases, so in order to increase the capacity of the battery cell, an insulator (500) must be able to be interposed between the reduced gap between the battery can (200) and the electrode assembly (100), and for this purpose, it is preferable that the thickness of the insulator (500) be as thin as possible.

[0058] Referring to FIG. 3, a battery can (200) may be formed with a closed portion (210) and an open portion (220) positioned opposite each other.

[0059] For example, with reference to FIG. 3, an opening (220) may be formed at the bottom of the battery can (200). The electrode assembly (100) is received through the opening (220) formed at the bottom of the battery can (200), and an electrolyte is also injected through the opening (220) formed at the bottom of the battery can (200).

[0060] That is, the battery can (200) is a roughly cylindrical container having an opening (220) formed at the bottom, and may be made of a conductive material such as metal, for example. The material of the battery can (200) may be made of a conductive metal such as aluminum, steel, stainless steel, etc., but is not limited thereto.

[0061] In addition, with reference to FIG. 3, a closure (210) may be formed on the upper portion of the battery can (200). The closure (210) may be partially formed on the opposite side of the open portion (220). A through hole (211) is formed in the closure (210), and as shown in FIG. 2, a cell terminal (400) is coupled to the through hole (211) and is electrically connected to the positive electrode collector plate (300) through the through hole (211). In addition, referring to FIG. 2, an insulator (500) may be interposed between the battery can (200) on the closure (210) side and the positive electrode collector plate (300).

[0062] The positive electrode collector plate (300) is electrically connected to the positive electrode plate (110), and for example, referring to FIG. 2, the positive electrode collector plate (300) is connected to the positive electrode plate (110) at the upper portion of the electrode assembly (100). Here, a fracture-inducing portion (700) may be formed on the positive electrode collector plate (300). As will be described in detail below, the present specification will focus on a case where the fracture-inducing portion (700) is formed on the negative electrode collector plate (600), and the case where the fracture-inducing portion (700) is formed on the positive electrode collector plate (300) will be replaced with a description of the negative electrode collector plate (600).

[0063] The positive electrode collector plate (300) is made of a conductive metal material and is connected to the first non-coated portion (111) of the electrode assembly (100). The positive electrode collector plate (300) can be coupled to the upper portion of a coupling surface formed by bending an end of the first non-coated portion (111) in a direction parallel to the positive electrode collector plate (300). The bending direction of the first non-coated portion (111) may be, for example, a direction toward the winding center of the electrode assembly (100).

[0064] When the first non-conductive portion (111) has a folded shape like this, the space occupied by the first non-conductive portion (111) is reduced, which can lead to an improvement in energy density. In addition, the increase in the bonding area between the first non-conductive portion (111) and the positive electrode current collector (300) can lead to an improvement in bonding strength and a reduction in resistance.

[0065] The cell terminal (400) is made of a conductive metal material and is coupled to a through hole (211) formed in a closed portion (210) of a battery can (200) and is electrically connected to a positive electrode collector plate (300) through the through hole (211). In addition, the cell terminal (400) is electrically connected to a positive electrode plate (110) of an electrode assembly (100) through the positive electrode collector plate (300), thereby having a positive polarity.

[0066] That is, the cell terminal (400) can function as a positive terminal. In addition, the battery can (200) is electrically connected to the negative plate (120) of the electrode assembly (100) as described above, thereby having a negative polarity.

[0067] Referring to FIG. 2, the negative electrode collector plate (600) is electrically connected to the negative electrode plate (120). Here, a fracture-inducing portion (700) may be formed on the negative electrode collector plate (600). However, a detailed description of the fracture-inducing portion (700) will be described later.

[0068] The negative electrode collector plate (600) is connected to the second non-conductive portion (121) of the electrode assembly (100). The negative electrode collector plate (600) is coupled to the lower portion of the electrode assembly (100). The negative electrode collector plate (600) is made of a conductive metal material such as aluminum, steel, copper, nickel, etc., and can be electrically connected to the second non-conductive portion (121) of the negative electrode plate (120).

[0069] The negative electrode collector plate (600) can be electrically connected to the battery can (200). To this end, at least a portion of the edge portion of the negative electrode collector plate (600) can be interposed and fixed between the inner surface of the battery can (200) and the sealing gasket (260).

[0070] In one embodiment, at least a portion of the edge portion of the negative electrode current collector (600) may be supported by the lower surface of the bead portion (240) formed at the lower end of the battery can (200) and fixed to the bead portion (240) by welding. In a modified embodiment, at least a portion of the edge portion of the negative electrode current collector (600) may be directly welded to the inner wall surface of the battery can (200).

[0071] And, at least a portion of the remaining portion, excluding the joining portion of the beading portion (240) of the negative electrode collector plate (600), can be joined to the folded surface of the second non-conductive portion (121) by welding, for example, laser welding.

[0072] Additionally, the negative electrode collector (600) may be electrically coupled to at least a portion of its edge on the upper and lower surfaces of the beading portion (240) adjacent to the crimping portion (250).

[0073] Referring to FIG. 2, the cap plate (230) is configured to seal the opening (220, see FIG. 3) formed at the bottom of the battery can (200). The cap plate (230) may be made of, for example, a metal material to ensure rigidity.

[0074] In addition, the cap plate (230) may be provided as non-polar by being separated from the electrode assembly (100). That is, the cap plate (230) may not have polarity even if it is provided as a conductive metal material.

[0075] The fact that the cap plate (230) does not have polarity means that the cap plate (230) is electrically insulated from the battery can (200) and the cell terminal (400). As such, the cap plate (230) does not have to have polarity, and its material does not necessarily have to be a conductive metal.

[0076] The cap plate (230) may be supported by being seated on the beading portion (240) formed on the battery can (200). In addition, the cap plate (230) is fixed by the crimping portion (250). A sealing gasket (260) may be interposed between the cap plate (230) and the crimping portion (250) of the battery can (200) to ensure airtightness of the battery can (200). That is, the sealing gasket (260) may be arranged to be interposed between the edge of the cap plate (230) and the opening portion (220) of the battery can (200).

[0077] A beading portion (240) and a crimping portion (250) can be formed at the bottom of the battery can (200).

[0078] The beading portion (240) is formed by pressing the outer circumference of the battery can (200) inward in an area adjacent to the opening (220) of the battery can (200).

[0079] The beading portion (240) supports the electrode assembly (100) so that the electrode assembly (100), which has a size roughly corresponding to the width of the battery can (200), does not escape through the opening (220) formed at the bottom of the battery can (200), and can also function as a support on which the cap plate (230) is mounted. In addition, the beading portion (240) can support the outer peripheral surface of the sealing gasket (260).

[0080] The crimping portion (250) is provided to extend and bend inwardly of the battery can (200) to wrap and secure the edge of the cap plate (230) together with the sealing gasket (260). Here, the crimping portion (250) is formed at the bottom of the battery can (200) based on the arrangement of the battery can (200). For example, when the battery can (200) is arranged such that the cell terminal (400) is positioned at the top as shown in FIG. 2, the crimping portion (250) is formed at the bottom of the battery can (200) based on FIG. 2. In addition, as shown in FIG. 2, the crimping portion (250) is formed at the bottom of the beading portion (240). However, this is merely one embodiment, and the positions of the crimping portion (250) and the beading portion (240) are not limited thereto.

[0081] In addition, the present invention does not exclude a case where the battery can (200) does not have at least one of the beading portion (240) and the crimping portion (250). In the present invention, when the battery can (200) does not have at least one of the beading portion (240) and the crimping portion (250), fixing of the electrode assembly (100), fixing of the cap plate (230), or sealing of the battery can (200) can be realized through at least one of additional application of a component that can function as a stopper for the electrode assembly (100), additional application of a structure on which the cap plate (230) can be secured, and welding between the battery can (200) and the cap plate (230).

[0082] Referring to Fig. 2, the crimping portion (250) is formed at the lower portion of the beading portion (240). The crimping portion (250) has an extended and bent shape so as to wrap around the edge of the cap plate (230) positioned at the lower portion of the beading portion (240). Due to the shape of the folded crimping portion (250), the cap plate (230) is fixed on the beading portion (240).

[0083] Meanwhile, the battery can (200) of the present invention may not have at least one of the beading portion (240) and the crimping portion (250), and in this case, the sealing gasket (260) may be interposed between the structure for fixing provided on the opening portion (220) side of the battery can (200) and the cap plate (230) to ensure the airtightness of the battery can (200).

[0084] For example, it is also possible to omit the crimping portion (250) and fix the cap plate (230) by covering the opening (220) of the battery can (200) through another fixing structure. For example, the applicant's published patent KR 10-2019-0030016 A discloses a cylindrical battery cell in which the beading portion (240) is omitted, and such a structure may be adopted in the present invention.

[0085] A vent notch (231) may be formed in the cap plate (230) so that it bursts when the pressure inside the battery can (200) exceeds a threshold.

[0086] For example, the vent notch (231) may be formed on both sides of the cap plate (230), and may be formed in at least one pattern among a continuous circular pattern, a discontinuous circular pattern, and a linear pattern on the surface of the cap plate (230). In addition, the vent notch (231) may be formed in various other patterns.

[0087] The vent notch (231) is formed at the bottom of the battery can (200) based on the arrangement of the battery can (200) in FIG. 2, and may be arranged so that gas inside the battery can (200) is discharged through the bottom of the battery can (200) when the vent notch (231) is ruptured. For example, when the battery can (200) is arranged such that the cell terminal (400) is positioned at the top as in FIG. 2, the vent notch (231) may be formed at the bottom of the battery can (200) based on FIG. 2.

[0088] The vent notch (231) may be formed as an area having a thinner thickness compared to the surrounding area of ​​the cap plate (230).

[0089] The vent notch (231) is thinner than the surrounding area and thus may be more easily broken than the surrounding area. When the internal pressure of the battery can (200) increases above a certain level, the vent notch (231) may be broken and gas generated inside the battery can (200) may be discharged.

[0090] For example, the vent notch (231) can be formed by partially reducing the thickness of the battery can (200) through notching on one side or both sides of the cap plate (230).

[0091] A cylindrical battery cell (10) according to one embodiment of the present invention may have a structure in which both a positive terminal and a negative terminal are present at the upper portion as shown in FIG. 2, and thus the upper portion structure is more complex than the lower portion structure.

[0092] Accordingly, a vent notch (231) may be formed on the cap plate (230) forming the lower surface of the cylindrical battery cell (10) to facilitate the discharge of gas generated inside the battery can (200).

[0093] In this way, if the gas generated inside the battery can (200) equipped in the cylindrical battery cell (10) is discharged downward, it can also be beneficial to the user's safety.

[0094] For example, if a cylindrical battery cell (10) is placed directly under the driver's seat in an electric vehicle, there may be a risk of safety accidents for the driver if gas is discharged upward. However, if the gas is discharged downwards of the battery can (200), as in the cylindrical battery cell (10) according to one embodiment of the present invention, the above-mentioned problem does not occur even if the cylindrical battery cell (10) is placed directly under the driver's seat in an electric vehicle.

[0095] Hereinafter, the fracture inducing portion (700) will be described. The fracture inducing portion (700) may be formed on a collector plate positioned in the direction in which gas is discharged. That is, the fracture inducing portion (700) may be formed on a collector plate electrically connecting an electrode assembly (100) located in a portion of a cylindrical battery cell (10) where a venting portion is formed.

[0096] In this embodiment, the venting portion is a vent notch (231) formed in the cap plate (230), and in this case, the fracture inducing portion (700) can be formed in the negative electrode collector plate (600) located at the portion where the vent notch (231) is formed.

[0097] For example, as described above, in FIG. 2, since the gas generated inside the battery can (200) provided in the cylindrical battery cell (10) is discharged downward, a fracture-inducing portion (700) is formed in the negative electrode collector plate (600) disposed at the bottom. In addition, although not shown in the drawing, if, for example, the gas is discharged through the upper portion of the cylindrical battery cell (10) and the positive electrode collector plate (300) is disposed at the upper portion, the fracture-inducing portion (700) may be formed in the positive electrode collector plate (300).

[0098] That is, depending on the direction of gas discharge, the fracture inducing portion (700) may be formed on the positive collector plate (300) or the negative collector plate (600). However, in the embodiment of FIG. 2, the fracture inducing portion (700) is formed on the negative collector plate (600), so for convenience of explanation, the following description will focus on the case where the fracture inducing portion (700) is formed on the negative collector plate (600). In addition, the embodiment where the fracture inducing portion (700) is formed on the positive collector plate (300) is replaced with the description of the embodiment where the fracture inducing portion (700) is formed on the negative collector plate (600).

[0099] As shown in Fig. 2, the fracture inducing portion (700) is formed on the negative electrode collector plate (600), and is configured so that at least a portion of the negative electrode collector plate (600) is fractured by gas generated inside the battery can (200).

[0100] Referring to FIG. 2, the negative electrode collector plate (600) is positioned between the center hole (140) of the electrode assembly (100) and the cap plate (230), so that when gas generated inside the battery can (200) moves toward the cap plate (230) through the center hole (140), the movement is impeded by the negative electrode collector plate (600).

[0101] That is, if the negative electrode collector (600) continues to maintain its original position, the gas generated inside the battery can (200) is not easily discharged due to the obstruction of the negative electrode collector (600), so the internal pressure of the battery can (200) increases. However, if the internal pressure of the battery can (200) is left unattended without being reduced, an explosion may occur in the cylindrical battery cell (10).

[0102] Therefore, in order to solve this problem, a cylindrical battery cell (10) according to one embodiment of the present invention is configured such that a fracture inducing portion (700) is formed on the negative electrode current collector (600) so that the negative electrode current collector (600) is fractured by the internal pressure of the battery can (200).

[0103] Referring to FIG. 4, the negative electrode collector (600) may be configured to include a border portion (610), a center portion (620), and a connection portion (630). In FIG. 4, the negative electrode collector (600) is illustrated as viewed from the opposite direction to FIG. 2. That is, in the case of FIG. 2, the center portion (620) is positioned above the border portion (610), but in FIG. 4, the center portion (620) is positioned below the border portion (610). This also applies to FIGS. 5 to 11.

[0104] The rim portion (610) defines a rim and may have a roughly rim shape in which at least a portion of the inner area is empty to form an inner space. In the case of FIG. 4, the rim portion (610) is illustrated as having a roughly circular rim shape, but the shape of the rim portion (610) is not limited thereto. Unlike the illustrated shape, the rim portion (610) may have a roughly square rim shape, a hexagonal rim shape, an octagonal rim shape, or other shapes. The rim portion (610) may be coupled to the connecting portion (630).

[0105] The central portion (620) is located on the inside of the rim portion (610) and is spaced apart from the rim portion (610). For example, the central portion (620) may be located at the exact center of the inner space of the rim portion (610), but is not limited thereto. In addition, the central portion (620) is coupled to the connecting portion (630) and is connected to the rim portion (610) by the connecting portion (630). In addition, the central portion (620) is coupled to the electrode assembly (100). Here, the central portion (620) may be positioned at a position corresponding to the central hole (140) of the electrode assembly (100).

[0106] The connecting portion (630) connects the edge portion (610) and the center portion (620). A plurality of connecting portions (630) may be provided, and the plurality of connecting portions (630) may be spaced apart from each other. In FIG. 4, four connecting portions (630) are provided, but the number of connecting portions (630) is not limited thereto. In addition, the plurality of connecting portions (630) may be arranged at equal intervals, but is not limited thereto.

[0107] Here, the fracture inducing portion (700) may be formed at various locations, for example, at the connecting portion (630). In one embodiment, as shown in FIG. 4, the fracture inducing portion (700) may be formed at the connecting portion (630) at the point where the central portion (620) and the connecting portion (630) meet. However, the fracture inducing portion (700) does not have to be formed only at the point where the central portion (620) and the connecting portion (630) meet, and may be formed at any portion of the connecting portion (630).

[0108] Referring to FIG. 4, the fracture inducing portion (700) may be formed as a groove, for example, a notching groove (710), in which the width of the connecting portion (630) narrows at the point where the center portion (620) and the connecting portion (630) meet. In addition, the notching groove (710) may be formed toward the inside of the connecting portion (630) in a direction (left and right direction of the connecting portion (630)) that gradually or continuously reduces the width of the connecting portion (630). That is, the notching groove (710) may be formed in the width direction from the outer end of the connecting portion (630) toward the inside. Here, the outer end of the connecting portion (630) is toward the edge portion (610), and the inner end of the connecting portion (630) is toward the center (620).

[0109] The shape of the notching groove (710) may vary. In Fig. 4, it is formed in a triangular shape, but is not limited thereto and may have a wider variety of shapes.

[0110] And, as shown in Fig. 4, the fracture inducing portion (700) may be provided in pairs and formed at each end of the connecting portion (630). For example, there may be four connecting portions (630), and eight notching grooves (710) may be formed, one pair per connecting portion (630), but this is not limited thereto.

[0111] In this way, when a fracture-inducing portion (700) such as a notched groove (710) is formed in the connecting portion (630), when the internal pressure of the battery can (200) increases, a fracture occurs in the connecting portion (630) along the notched groove (710), and the central portion (620) coupled to the electrode assembly (100) can also be easily removed.

[0112] And, when the center (620) is removed and the center hole (140) of the electrode assembly (100) is opened, the gas inside the battery can (200) moves toward the cap plate (230) through the center hole (140) and ruptures the vent notch (231) formed in the cap plate (230). As a result, the gas inside the battery can (200) can be easily discharged from the battery can (200).

[0113] In addition, not only can the internal pressure of the cylindrical battery cell (10) be reduced by the discharge of gas inside the battery can (200), but also an explosion of the cylindrical battery cell (10) can be prevented.

[0114] FIGS. 5 to 10 are each a perspective view of a negative electrode collector plate according to a modified embodiment of FIG. 4, and FIG. 11 is a perspective view of a shape of the negative electrode collector plate of FIG. 10 that has been modified.

[0115] In the modified embodiments of FIGS. 5 to 11, the common parts described in the embodiment of FIG. 4 are replaced with the aforementioned description. In addition, the parts described in the embodiment of FIG. 4 that are applicable to the modified embodiments of FIGS. 5 to 11 can be applied to the modified embodiments of FIGS. 5 to 11.

[0116] Referring to FIG. 5, the fracture inducing portion (700) may be formed as a groove, for example, a notching groove (710), as in FIG. 4. However, in the case of FIG. 4, the groove is formed in a form in which the width (left-right direction) of the connecting portion (630) becomes narrower, whereas in the case of FIG. 5, the groove is formed in a form in which the thickness (up-down direction) of the connecting portion (630) becomes narrower. That is, the notching groove (710) may be formed by being drawn inward toward the connecting portion (630) in a direction in which the thickness of the connecting portion (630) is gradually or continuously reduced.

[0117] Referring to FIG. 5, the notching groove (710) may be formed at the upper and lower portions of the connection portion (630), respectively, at the point where the center portion (620) and the connection portion (630) meet. Likewise, even when the notching groove (710) is formed in a groove in which the thickness of the connection portion (630) becomes narrower, the connection portion (630) may be broken along the notching groove (710) due to the internal pressure of the battery can (200).

[0118] Referring to Fig. 6, the fracture inducing portion (700) may be formed as a through hole (720). Here, the through hole (720) may be formed in any part of the connecting portion (630). For example, the through hole (720) may be formed in the middle of the connecting portion (630), or may be formed in the connecting portion (630) at the point where the central portion (620) and the connecting portion (630) meet.

[0119] The number of through holes (720) may vary. For example, although FIG. 6 illustrates one through hole (720) in one connection portion (630), this is only one embodiment, and the number of through holes (720) formed in one connection portion (630) may vary.

[0120] In addition, the through hole (720) may have various shapes. For example, in FIG. 6, a circular through hole (720) is illustrated in the connecting portion (630), but this is only one embodiment, and the shape of the through hole (720) may be various, such as an oval, a triangle, or a square.

[0121] In this way, when a through hole (720) is formed in the connecting portion (630), a break may easily occur in the connecting portion (630) due to the internal pressure of the battery can (200).

[0122] And, referring to Fig. 7, the fracture inducing part (700) further has a notched groove (710) formed in a circular through hole (720). That is, a pair of triangular notched grooves (710) are formed toward the outside from the periphery of the circular through hole (720). Here, the pair of notched grooves (710) may be formed to face opposite directions. Here, the shapes of the through hole (720) and the notched groove (710) may vary.

[0123] Referring to Fig. 8, the fracture inducing portion (700) may be configured to include a twist portion (730) formed by twisting the connecting portion (630). The twist portion (730) may be formed by cutting the portion of the connecting portion (630) that is joined to the edge portion (610), twisting it so that the opposite surface (lower surface) is positioned upward, and welding it to the edge portion (610).

[0124] In addition, when twisting the connecting portion (630) and joining it to the edge portion (610), the degree of welding can be adjusted to induce a break so that the edge portion (610) and the connecting portion (630) can be easily broken. Here, a cut portion or a groove (e.g., a notching groove) can be formed at the portion where the edge portion (610) and the twisted portion (730) meet, thereby making it easier to break the edge portion (610) and the connecting portion (630).

[0125] For example, the twisting portion (730) may be configured to include a first portion (731) and a second portion (732). The first portion (731) is connected to the center portion (620). Then, the second portion (732) is twisted and folded from the first portion (731) and then connected to the edge portion (610).

[0126] In this way, when a twisting portion (730) is formed in the connecting portion (630), the gas inside the battery can (200) moves and collides with the twisting portion (730), causing it to rotate. As the gas moves and rotates, energy consumption increases, and also, since the force is evenly distributed in each direction, there is an effect of reducing the explosive power caused by the gas.

[0127] In addition, when welding the connecting portion (630) in which the twisted portion (730) is formed to the edge portion (610), the welding degree can be controlled, or a cut portion or groove (e.g., a notching groove) can be formed to facilitate the breaking of the edge portion (610) and the connecting portion (630) by gas.

[0128] That is, the embodiment of FIG. 8 facilitates the breakage of the edge portion (610) and the connection portion (630) provided in the negative electrode collector (600), thereby facilitating gas discharge, thereby preventing internal pressure and explosion. In addition, it also has the effect of reducing the explosive power caused by the gas by consuming the energy possessed by the gas and uniformly distributing the force through the rotation of the gas through the twisting portion (730).

[0129] FIG. 9 is a modified embodiment of FIG. 8, in which the twisting portion (730) is formed in a curved shape so as to rotate the gas. The twisting portion (730) may have various curved shapes, and for example, referring to FIG. 9, the twisting portion (730) may be configured such that the connecting portion (630) rotates 180 degrees from the center (620) and is coupled to the edge portion (610).

[0130] And, as in Fig. 9, a notching groove (710) may be formed in the second part (732) of the twisted part (730).

[0131] The embodiment of Fig. 9 is more advantageous in terms of gas rotation than the embodiment of Fig. 8. However, the embodiment of Fig. 8 and the embodiment of Fig. 9 may be appropriately selected as needed.

[0132] Meanwhile, the detailed description of the embodiment of Fig. 9 is replaced with the part described in Fig. 8.

[0133] Referring to Fig. 10, the fracture inducing portion (700) is formed as a groove, for example, a notched groove (710). In addition, the groove is formed in a shape in which the thickness (upper and lower direction) of the connecting portion (630) becomes narrower. However, while in Fig. 5, the notched grooves (710) are provided in pairs and formed on both the upper and lower portions of the connecting portion (630), in Fig. 10, the notched grooves (710) are formed only on the upper portion of the connecting portion (630), which is different.

[0134] In the case where the notching groove (710) is formed only at the upper portion of the connection portion (630) as in Fig. 10, the center portion (620) of the negative electrode current collector (600) moves in the opposite direction (see the arrow in Fig. 11) due to the gas inside the battery can (200) as in Fig. 11. When the center portion (620) is flipped in the opposite direction in this way, the gas inside the battery can (200) is easily discharged. Here, if the gas continues to be generated after the center portion (620) is flipped in the opposite direction, a break may eventually occur in the center portion (620) and the connection portion (630). Of course, in the embodiment of Fig. 5 as well, the center portion (620) of the negative electrode current collector (600) may be flipped in the opposite direction due to the gas inside the battery can (200) as in Fig. 10.

[0135] FIG. 12 is a schematic drawing showing the configuration of a battery pack including a cylindrical battery cell according to each embodiment of the present invention.

[0136] Referring to FIG. 12, a battery pack (20) according to one embodiment of the present invention may include one or more cylindrical battery cells (10) according to one embodiment of the present invention as described above. In addition, the battery pack (20) may further include a pack housing (200) for storing the cylindrical battery cells (10), and various devices for controlling charging and discharging of the cylindrical battery cells (10), such as a BMS, a current sensor, a fuse, etc.

[0137] FIG. 13 is a drawing for explaining a vehicle including a battery pack according to each embodiment of the present invention.

[0138] Referring to FIG. 13, a vehicle (30) according to one embodiment of the present invention may include one or more cylindrical battery cells (10) or battery packs (20) according to each of the above-described embodiments. Here, the vehicle (30) includes various types of vehicles that are designed to use electricity, such as electric vehicles or hybrid vehicles.

[0139] In this specification, when terms indicating directions such as up, down, left, and right are used, these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the location of the target object or the location of the observer.

[0140] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and those skilled in the art to which the present invention pertains may make various modifications and variations within the scope of the technical spirit of the present invention and the equivalent scope of the claims to be described below. Therefore, the embodiments disclosed above should be considered in an illustrative rather than a restrictive sense. In other words, the true scope of the technical spirit of the present invention is set forth in the claims, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

[0141] The present invention relates to a cylindrical battery cell, a battery pack including the same, an automobile, and a current collector, and is particularly applicable to industries related to secondary batteries.

Claims

1. An electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction; A cylindrical battery can in which the electrode assembly is housed and a through hole is formed; A positive electrode collector electrically connected to the positive electrode plate; a cell terminal connected to the positive electrode collector plate through a through hole in the battery can; and It includes a negative electrode current collector plate electrically connected to the above negative electrode plate, A cylindrical battery cell characterized in that a fracture-inducing portion is formed on the positive electrode current collector or the negative electrode current collector so that at least a portion of the positive electrode current collector or the negative electrode current collector is fractured by gas generated inside the battery can.

2. In paragraph 1, The above positive electrode collector plate or the above negative electrode collector plate, A border that defines the border; a central portion spaced apart from the above-mentioned edge portion and coupled to the electrode assembly; and A cylindrical battery cell characterized by including a connecting portion connecting the edge portion and the center portion.

3. In paragraph 2, The above fracture induction part is, A cylindrical battery cell characterized by being formed in the above connecting portion.

4. In paragraph 2, The above fracture induction part is, A cylindrical battery cell characterized in that the connection part is formed at the point where the center part and the connection part meet.

5. In paragraph 1, A cylindrical battery cell characterized in that the above-mentioned fracture-inducing portion is formed as a notching groove.

6. In paragraph 1, A cylindrical battery cell characterized in that the above-mentioned fracture-inducing portion is formed as a through hole.

7. In paragraph 5, There are four above-mentioned connections, A cylindrical battery cell characterized in that the above-mentioned notching grooves are formed in pairs in total of eight at each of the above-mentioned connecting portions.

8. In paragraph 5, A cylindrical battery cell characterized in that the notching groove is formed toward the inside of the connecting portion in a direction that gradually or continuously reduces the width or thickness of the connecting portion.

9. In paragraph 2, A cylindrical battery cell characterized in that the above-mentioned fracture-inducing portion comprises a twisted portion formed by twisting the above-mentioned connecting portion.

10. In paragraph 9, The above twisted part is, a first part connected to the center; and A cylindrical battery cell characterized by including a second part that is twisted and folded from the first part and then joined to the edge part.

11. In paragraph 9, A cylindrical battery cell characterized in that the above-mentioned twisted portion is formed in a curved shape so as to rotate gas.

12. In paragraph 11, A cylindrical battery cell characterized in that the twisted portion is configured such that the connecting portion is rotated 180 degrees from the center and is joined to the edge portion.

13. A battery pack comprising at least one cylindrical battery cell according to any one of claims 1 to 12.

14. A vehicle comprising at least one cylindrical battery cell according to any one of claims 1 to 12.

15. A current collector that electrically connects an electrode assembly located in a portion where a venting portion is formed in a cylindrical battery cell. A border that defines the border; a central portion spaced apart from the above-mentioned edge portion and coupled to the electrode assembly; and It includes a connecting portion connecting the above-mentioned border portion and the above-mentioned center portion, A current collector plate characterized in that a fracture-inducing portion is formed on the current collector plate so that at least a portion of the current collector plate is fractured by gas generated from the cylindrical battery cell.

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