Cylindrical battery cells, battery packs and automobiles containing them, and current collector plates.

Abstract

A cylindrical battery cell, a battery pack and an automobile containing the same, and a current collector plate are disclosed. A cylindrical battery cell according to one embodiment of the present invention includes an electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separator membrane 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 which has through holes formed therein, 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 holes of the battery can, and a negative electrode current collector plate electrically connected to the negative electrode plate, wherein a fracture induction portion is formed on the positive electrode current collector plate or the negative electrode current collector plate such that at least a part of the positive electrode current collector plate or the negative electrode current collector plate fractures due to gas generated inside the battery can.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0099233 filed on July 28, 2023, and all the content disclosed in the specification and drawings of the said application is incorporated into this application.

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

Background Art

[0003] Secondary batteries, which are easily applicable according to product groups and have electrical characteristics such as high energy density, are not only universally applied to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), etc., which are driven by an electric drive source.

[0004] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels but also are environmentally friendly in that no by-products are generated during energy use, and are attracting attention as a new energy source for improving energy efficiency.

[0005] Currently, the types of secondary batteries widely used include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such a single secondary battery cell is about 2.5V to 4.5V.

[0006] Therefore, if a higher output voltage is required, multiple battery cells can be connected in series to form a battery module or battery pack. Alternatively, multiple battery cells can be connected in parallel to form a battery module or battery pack depending on the required charge / discharge capacity. Thus, the number of battery cells and the electrical connection configuration included in a battery module or battery pack can be set in various ways depending on at least one of the required output voltage and charge / discharge capacity.

[0007] In addition, cylindrical, prismatic, and pouch-type battery cells are known as secondary battery cells. In the case of cylindrical battery cells, an insulating separator membrane is interposed between the positive and negative electrodes, and this is wound up to form an electrode assembly in the form of a jelly roll, which is then placed in a battery case together with the electrolyte to constitute the battery. A current collector plate may be used to electrically connect the positive and negative electrodes of the cylindrical battery cell.

[0008] Cylindrical battery cells can explode if the internal pressure increases due to the generation of gas inside the electrode assembly during repeated charge-discharge cycles, and if this internal pressure is not reduced. Therefore, vents can be formed in cylindrical battery cells in various ways.

[0009] However, in the case of conventional cylindrical battery cells, the current collector plate obstructs the space between the center of the electrode assembly and the vent, which presents a problem as gas discharge is not easy. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a cylindrical battery cell, a battery pack and an automobile containing the same, and a current collector plate, which can prevent explosion by reducing the internal pressure when gas is generated inside the cylindrical battery cell and the internal pressure increases, by deforming the shape of the current collector plate.

[0011] However, the technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0012] According to one aspect of the present invention, a cylindrical battery cell can be provided that includes an electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separation membrane 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 which has through holes formed therein; 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 holes of the battery can; and a negative electrode current collector plate electrically connected to the negative electrode plate, wherein a fracture induction portion is formed on the positive electrode current collector plate or the negative electrode current collector plate such that at least a part of the positive electrode current collector plate or the negative electrode current collector plate fractures due to gas generated inside the battery can.

[0013] In one embodiment, the positive electrode current collector plate or the negative electrode current collector plate may include a peripheral portion defining the periphery, a central portion separated from the peripheral portion and coupled to the electrode assembly, and a connecting portion connecting the peripheral portion and the central portion.

[0014] In one embodiment, the fracture induction portion may be formed in the connection portion.

[0015] In one embodiment, the fracture induction portion may be formed in the connecting portion at the point where the central portion and the connecting portion come into contact.

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

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

[0018] In one embodiment, there are four connection parts, and a total of eight notch grooves may be formed, one pair per connection part.

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

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

[0021] In one embodiment, the twisted portion may include a first portion connected to the central part and a second portion that is twisted and folded from the first portion and then connected to the peripheral part.

[0022] In one embodiment, the twisted portion may be formed in a curved shape to rotate the gas.

[0023] In one embodiment, the twisted portion may be configured such that the connecting portion rotates 180° from the center and connects to the peripheral portion.

[0024] Furthermore, according to another aspect of the present invention, a battery pack comprising at least one of the aforementioned cylindrical battery cells is provided, and an automobile comprising at least one of the aforementioned cylindrical battery cells is also provided.

[0025] Furthermore, according to yet another aspect of the present invention, a current collector plate is provided for electrically connecting an electrode assembly located in a portion of a cylindrical battery cell where a vent portion is formed, comprising: a peripheral portion defining the periphery; a central portion separated from the peripheral portion and coupled with the electrode assembly; and a connecting portion connecting the peripheral portion and the central portion, wherein a fracture-inducing portion is formed on the current collector plate such that at least a part of the current collector plate fractures due to gas generated in the cylindrical battery cell. [Effects of the Invention]

[0026] According to an embodiment of the present invention, when gas is generated inside the cylindrical battery cell and the internal pressure increases, the internal pressure is reduced by the deformation of the shape of the current collector plate.

[0027] In addition, an explosion of the cylindrical battery cell can be prevented.

[0028] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Brief Description of the Drawings

[0029] The following drawings attached to this specification illustrate desirable embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings. [Figure 1] It is a perspective view of a cylindrical battery cell according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present invention. [Figure 3] It is a view showing a battery can in a cylindrical battery cell according to an embodiment of the present invention. [Figure 4] It is a perspective view of a negative electrode current collector plate of a cylindrical battery cell according to an embodiment of the present invention. [[ID=二十九]] [Figure 5] It is a perspective view of a negative electrode current collector plate according to a modified embodiment of FIG. 4. [Figure 6] It is a perspective view of a negative electrode current collector plate according to a modified embodiment of FIG. 4. [Figure 7] It is a perspective view of a negative electrode current collector plate according to a modified embodiment of FIG. 4. [Figure 8] It is a perspective view of a negative electrode current collector plate according to a modified embodiment of FIG. 4. [Figure 9] It is a perspective view of a negative electrode current collector plate according to a modified embodiment of FIG. 4. [Figure 10]Figure 4 is a perspective view of the negative electrode current collector plate according to a modified embodiment. [Figure 11] Figure 10 is a perspective view showing how the shape of the negative electrode current collector plate has been deformed. [Figure 12] This figure schematically shows the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention. [Figure 13] This is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention. [Modes for carrying out the invention]

[0030] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concepts of terms in order to best describe the invention. Accordingly, it should be understood that the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entirety of the technical idea of ​​the present invention, and that there may be a variety of equivalents and modifications that can be substituted therein at the time of this application.

[0031] The size of each component or specific part of a component in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity and ease of explanation. Therefore, the size of each component may not fully reflect its actual size. Specific descriptions of known functions or configurations related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention.

[0032] As used herein, the terms “joining” or “connecting” include 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 via a connecting member.

[0033] Figure 1 is a perspective view of a cylindrical battery cell according to one embodiment of the present invention, Figure 2 is a cross-sectional view of a cylindrical battery cell according to one embodiment of the present invention, Figure 3 shows the battery casing in a cylindrical battery cell according to one embodiment of the present invention, and Figure 4 is a perspective view of the negative electrode current collector plate of a cylindrical battery cell according to one embodiment of the present invention.

[0034] Referring to Figures 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 current collector plate 300, cell terminals 400, and a negative electrode current collector plate 600.

[0035] Referring to Figure 2, the electrode assembly 100 has a structure in which a positive electrode plate 110, a negative electrode plate 120, and a separation membrane 130 interposed between the positive electrode plate 110 and the negative electrode plate 120 are wound in one direction. A central hole 140 is formed in the center of the electrode assembly 100, and it can be formed in a jelly roll shape.

[0036] For example, the electrode assembly 100 can be manufactured by winding up a laminate formed by sequentially stacking a negative electrode plate 120, a separation membrane 130, a positive electrode plate 110, and another separation membrane 130 at least once. Here, the positive electrode plate 110 and the negative electrode plate 120 can be formed in sheet form.

[0037] That is, the electrode assembly 100 to be applied to this embodiment may be a winding type electrode assembly 100. In this case, the outer circumferential surface of the electrode assembly 100 may be further provided with a separation film for insulation from the battery can 200. That is, the electrode assembly 100 may have any known winding structure in the relevant art without limitation.

[0038] The positive electrode plate 110 has positive electrode active material coated on one or both sides, and a first uncoated portion 111 (see Figure 2) where the positive electrode active material is not coated may be formed at the end of the positive electrode plate 110. Figure 2 shows a positive electrode plate 110 with the first uncoated portion 111 formed thereon, but a cylindrical battery cell 10 according to one embodiment of the present invention also includes embodiments relating to a positive electrode plate 110 in which the first uncoated portion 111 is not formed. However, for the sake of explanation, the following description will focus on the case in which the first uncoated portion 111 is formed on the positive electrode plate 110. The first uncoated portion 111 is exposed to the outside of the separator membrane 130 while forming multiple winding turns with respect to the center of the electrode assembly 100, and can be used as an electrode tab.

[0039] The negative electrode plate 120 has a negative electrode active material coated on one or both sides, and a second uncoated portion 121 (see Figure 2) where the negative electrode active material is not coated may be formed at the end of the negative electrode plate 120. Figure 2 shows a negative electrode plate 120 with the second uncoated portion 121 formed thereon, but the cylindrical battery cell 10 according to one embodiment of the present invention also includes embodiments relating to a negative electrode plate 120 in which the second uncoated portion 121 is not formed. However, for the sake of explanation, the following description will focus on the case in which the second uncoated portion 121 is formed on the negative electrode plate 120. The second uncoated portion 121 is exposed to the outside of the separation membrane 130 while forming multiple turns with respect to the center of the electrode assembly 100, and can be used as an electrode portion.

[0040] That is, at least one of the positive electrode plate 110 and the negative electrode plate 120 may each include an uncoated portion at the long edge in the winding direction where the active material is not applied. The first uncoated portion 111 and the second uncoated portion 121 may be configured to face in opposite directions.

[0041] Here, the positive electrode active material applied to the positive electrode plate 110 and the negative electrode active material applied to the negative electrode plate 120 can be any active material known in the industry without limitation.

[0042] Furthermore, the separation membrane 130 can be made using porous polymer films, such as porous polymer films made from polyolefin polymers like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, or ethylene / methacrylate copolymer, either alone or in a laminated configuration.

[0043] As another example, the separation membrane 130 may be made of a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0044] At least one surface of the separation membrane 130 may include a coating layer of inorganic particles. Furthermore, the separation membrane 130 itself may consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound to a binder such that interstitial volumes exist between adjacent particles.

[0045] Furthermore, the central hole 140 of the electrode assembly 100 can be used for welding the cell terminal 400 (positive electrode terminal) and the positive electrode current collector plate 300. That is, the electrode assembly 100 can be configured to weld the cell terminal 400 and the positive electrode current collector plate 300 by irradiating them with a laser from the central hole 140.

[0046] Referring to Figure 2, the electrode assembly 100 is housed in the battery can 200. Then, referring to Figure 3, a through hole 211 is formed in the battery can 200. For example, the battery can 200 is formed in a cylindrical shape, 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. As a result, the battery can 200 can have the same polarity as the negative electrode plate 120, i.e., be a negative electrode.

[0047] 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 predetermined size is formed between the battery can 200 and the positive electrode current collector plate 300, and an insulator 500 may be interposed in the gap.

[0048] If the size of the electrode assembly 100 is increased while the size of the battery can 200 is determined by the standard, the total capacity of the battery cells will increase, but the distance between the battery can 200 and the electrode assembly 100 will decrease.

[0049] In other words, if the size of the electrode assembly 100 is increased to increase the total capacity of the battery cell, the distance between the battery can 200 and the electrode assembly 100 decreases. Therefore, in order to increase the capacity of the battery cell, an insulator 500 should be interposed in the reduced distance between the battery can 200 and the electrode assembly 100. For this reason, it is desirable that the thickness of the insulator 500 be as thin as possible.

[0050] Referring to Figure 3, the battery can 200 may have a closed section 210 and an open section 220 that are positioned opposite each other.

[0051] For example, using Figure 3 as a reference, an opening 220 may be formed at the bottom of the battery can 200. The electrode assembly 100 is housed in the battery can 200 through the opening 220 formed at the bottom, and the electrolyte is also injected through the opening 220 formed at the bottom of the battery can 200.

[0052] In other words, the battery can 200 is a substantially cylindrical housing with an open portion 220 formed at its bottom, and may be made of a conductive material such as metal. The material of the battery can 200 may be made of a conductive metal, such as aluminum, steel, or stainless steel, but is not limited to these.

[0053] Furthermore, with reference to Figure 3, a closed portion 210 may be formed on the upper part of the battery can 200. The closed portion 210 may be partially formed on the opposite side of the open portion 220. A through hole 211 is formed in the closed portion 210, and as shown in Figure 2, the cell terminal 400 is connected to the through hole 211 and electrically connected to the positive electrode current collector plate 300 through the through hole 211. Referring to Figure 2, an insulator 500 may be interposed between the battery can 200 on the closed portion 210 side and the positive electrode current collector plate 300.

[0054] The positive electrode current collector plate 300 is electrically connected to the positive electrode plate 110. For example, referring to Figure 2, the positive electrode current collector plate 300 is connected to the positive electrode plate 110 at the top of the electrode assembly 100. Here, a fracture induction portion 700 may be formed on the positive electrode current collector plate 300. As will be explained in detail below, this specification will mainly describe the case in which the fracture induction portion 700 is formed on the negative electrode current collector plate 600, and the description of the case in which the fracture induction portion 700 is formed on the positive electrode current collector plate 300 will be replaced by the description relating to the negative electrode current collector plate 600.

[0055] The positive electrode current collector plate 300 is made of a conductive metal material and is connected to the first uncoated portion 111 of the electrode assembly 100. The positive electrode current collector plate 300 can be connected to the upper part of a coupling surface formed by bending the end of the first uncoated portion 111 parallel to the positive electrode current collector plate 300. The bending direction of the first uncoated portion 111 may be, for example, towards the winding center of the electrode assembly 100.

[0056] When the first uncoated portion 111 has this folded shape, the space occupied by the first uncoated portion 111 is reduced, which can improve energy density. In addition, by increasing the bonding area between the first uncoated portion 111 and the positive electrode current collector plate 300, it is possible to improve bonding strength and reduce resistance.

[0057] The cell terminal 400 is made of a conductive metal material and is connected to a through hole 211 formed in the closed portion 210 of the battery can 200, and is electrically connected to the positive electrode current collector plate 300 through the through hole 211. The cell terminal 400 is then electrically connected to the positive electrode plate 110 of the electrode assembly 100 via the positive electrode current collector plate 300, thereby having positive polarity.

[0058] In other words, the cell terminal 400 can function as a positive terminal. The battery can 200 is electrically connected to the negative electrode plate 120 of the electrode assembly 100, as described above, and thus has negative polarity.

[0059] Referring to Figure 2, the negative electrode current collector plate 600 is electrically connected to the negative electrode plate 120. Here, a fracture induction portion 700 may be formed on the negative electrode current collector plate 600. However, a detailed explanation of the fracture induction portion 700 will be given later.

[0060] The negative electrode current collector plate 600 is connected to the second uncoated portion 121 of the electrode assembly 100. The negative electrode current collector plate 600 is coupled to the lower part of the electrode assembly 100. The negative electrode current collector plate 600 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and can be electrically connected to the second uncoated portion 121 of the negative electrode plate 120.

[0061] The negative electrode current collector plate 600 can be electrically connected to the battery can 200. To achieve this, at least a portion of the peripheral edge of the negative electrode current collector plate 600 can be interposed and fixed between the inner surface of the battery can 200 and the sealing gasket 260.

[0062] In one embodiment, at least a portion of the peripheral edge of the negative electrode current collector plate 600 can be fixed to the beading portion 240 by welding while being supported by the lower end surface of the beading portion 240 formed at the lower end of the battery can 200. In a modified embodiment, at least a portion of the peripheral edge of the negative electrode current collector plate 600 can be directly welded to the inner surface of the battery can 200.

[0063] Furthermore, at least a portion of the remaining part of the negative electrode current collector plate 600, excluding the joint portion of the beading portion 240, can be joined to the bent surface of the second uncoated portion 121 by welding, for example, laser welding.

[0064] Furthermore, at least one of the peripheral edges of the negative electrode current collector plate 600 can be electrically coupled to the upper and lower surfaces of the beading portion 240 that are adjacent to the crimping portion 250.

[0065] Referring to Figure 2, the cap plate 230 is configured to seal the opening 220 (see Figure 3) formed at the lower end of the battery can 200. The cap plate 230 may be made of a metal material, for example, to ensure rigidity.

[0066] Furthermore, the cap plate 230 can be separated from the electrode assembly 100 and provided in a non-polar manner. That is, even if the cap plate 230 is provided as a conductive metallic material, it will not have polarity.

[0067] The fact that the cap plate 230 has no polarity means that the cap plate 230 is electrically insulated from the battery can 200 and the cell terminals 400. Thus, the cap plate 230 does not need to have polarity, and its material does not necessarily have to be a conductive metal.

[0068] The cap plate 230 can be mounted and supported on a beading portion 240 formed on the battery can 200. The cap plate 230 is also fixed by a 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 the airtightness of the battery can 200. That is, the sealing gasket 260 may be provided so as to be interposed between the peripheral edge of the cap plate 230 and the open portion 220 of the battery can 200.

[0069] A beading section 240 and a crimping section 250 may be formed at the bottom of the battery can 200.

[0070] The beading portion 240 is formed by press-fitting the outer surface of the battery can 200 inward in the region adjacent to the opening portion 220 of the battery can 200.

[0071] The beading portion 240 supports the electrode assembly 100, which has a size approximately corresponding to the width of the battery can 200, so as not to come out of the opening 220 formed at the bottom of the battery can 200, and can also function as a support for mounting the cap plate 230. In addition, the beading portion 240 can support the outer surface of the sealing gasket 260.

[0072] The crimping portion 250 extends inward from the battery can 200 and is bent to surround and secure the periphery 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, if the battery can 200 is arranged so that the cell terminals 400 are located at the top, as shown in Figure 2, the crimping portion 250 is formed at the bottom of the battery can 200, based on Figure 2. And, as shown in Figure 2, the crimping portion 250 is formed at the bottom of the beading portion 240. However, this is only one embodiment, and the positions of the crimping portion 250 and the beading portion 240 are not limited to this.

[0073] The present invention does not exclude cases 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, if the battery can 200 does not have at least one of the beading portion 240 and the crimping portion 250, fixing the electrode assembly 100, fixing the cap plate 230, or sealing the battery can 200 can be achieved by at least one of the following: additional application of a component that can function as a stopper to the electrode assembly 100, additional application of a structure on which the cap plate 230 can be provided, or welding of the battery can 200 and the cap plate 230.

[0074] Based on Figure 2, the crimping portion 250 is formed at the bottom of the beading portion 240. The crimping portion 250 has a shape that extends and bends to surround the periphery of the cap plate 230, which is positioned at the bottom of the beading portion 240. The shape of the bent crimping portion 250 fixes the cap plate 230 to the beading portion 240.

[0075] On the other hand, the battery can 200 of the present invention does not necessarily have to have at least one of the beading portion 240 and the crimping portion 250. In this case, the sealing gasket 260 may be interposed between the fixing structure provided on the open portion 220 side of the battery can 200 and the cap plate 230 in order to ensure the airtightness of the battery can 200.

[0076] For example, the crimping portion 250 may be omitted, and the cap plate 230 may be fixed to cover the opening 220 of the battery can 200 by other fixing structures. For example, the applicant's Korean Published Patent No. 10-2019-0030016 discloses a cylindrical battery cell in which the beading portion 240 is omitted, and such a structure may be adopted in the present invention.

[0077] A vent notch 231 may be formed in the cap plate 230 so as to rupture if the internal pressure of the battery can 200 exceeds a critical value.

[0078] For example, the vent notches 231 may be formed on both sides of the cap plate 230, and on the surface of the cap plate 230, they may be formed in at least one of a continuous circular pattern, a discontinuous circular pattern, and a linear pattern. In addition, the vent notches 231 may be formed in a variety of other patterns.

[0079] The vent notch 231 is formed at the lower end of the battery can 200, based on the arrangement of the battery can 200 in Figure 2, and is designed so that when the vent notch 231 ruptures, the gas inside the battery can 200 is discharged from the lower end of the battery can 200. For example, if the battery can 200 is arranged so that the cell terminals 400 are located at the upper end, as shown in Figure 2, the vent notch 231 may be formed at the lower end of the battery can 200, based on Figure 2.

[0080] The vent notch 231 may be formed in the cap plate 230 as a region having a thinner thickness than the surrounding region.

[0081] Because the vent notch 231 is thinner than the surrounding area, it is more easily ruptured than the surrounding area, and when the internal pressure of the battery can 200 increases above a certain level, the vent notch 231 ruptures, allowing the gas generated inside the battery can 200 to be released.

[0082] For example, the vent notch 231 may be formed by notching one or both sides of the cap plate 230 to partially reduce the thickness of the battery can 200.

[0083] A cylindrical battery cell 10 according to one embodiment of the present invention can have a structure in which both positive and negative terminals are present at the top, with reference to Figure 2, and this makes the upper structure more complex than the lower structure.

[0084] Therefore, a vent notch 231 may be formed in the cap plate 230 that forms the lower surface of the cylindrical battery cell 10 in order to facilitate the smooth discharge of gas generated inside the battery can 200.

[0085] Thus, if the gas generated inside the battery can 200 provided in the cylindrical battery cell 10 is discharged downward, it may also be advantageous for the user's safety.

[0086] For example, if the cylindrical battery cell 10 is placed directly beneath the driver's seat of an electric vehicle, the gas could be discharged upwards, potentially posing a safety risk to the driver. However, if the gas is discharged downwards from the battery can 200, as in the cylindrical battery cell 10 according to one embodiment of the present invention, the aforementioned problem does not occur even if the cylindrical battery cell 10 is placed directly beneath the driver's seat of an electric vehicle.

[0087] The fracture induction portion 700 will now be described. The fracture induction portion 700 may be formed on a current collector plate positioned in the direction from which gas is discharged. That is, in a cylindrical battery cell 10, the fracture induction portion 700 may be formed on a current collector plate that electrically connects the electrode assembly 100 located in the portion where the vent portion is formed.

[0088] In this embodiment, the vent portion is a vent notch 231 formed in the cap plate 230, and in this case, the fracture guide portion 700 can be formed in the negative electrode current collector plate 600 located in the portion where the vent notch 231 is formed.

[0089] For example, as mentioned above, in Figure 2, the gas generated inside the battery can 200 provided in the cylindrical battery cell 10 is discharged downwards, so a fracture induction portion 700 is formed on the negative electrode current collector plate 600 located at the bottom. And, although not shown, if, for example, the gas is discharged from the top of the cylindrical battery cell 10 and the positive electrode current collector plate 300 is located at the top, the fracture induction portion 700 can be formed on the positive electrode current collector plate 300.

[0090] That is, depending on the direction of gas discharge, the fracture induction portion 700 may be formed on the positive electrode current collector plate 300 or on the negative electrode current collector plate 600. However, in the embodiment shown in Figure 2, the fracture induction portion 700 is formed on the negative electrode current collector plate 600, so for the sake of explanation, the following description will focus on the case where the fracture induction portion 700 is formed on the negative electrode current collector plate 600. Furthermore, in embodiments where the fracture induction portion 700 is formed on the positive electrode current collector plate 300, the description of the embodiment where the fracture induction portion 700 is formed on the negative electrode current collector plate 600 will be used instead.

[0091] As shown in Figure 2, the fracture induction portion 700 is formed on the negative electrode current collector plate 600, and is configured such that at least a portion of the negative electrode current collector plate 600 fractures due to gas generated inside the battery can 200.

[0092] Referring to Figure 2, the negative electrode current collector plate 600 is positioned between the central hole 140 of the electrode assembly 100 and the cap plate 230. Therefore, when gas generated inside the battery can 200 moves from the central hole 140 towards the cap plate 230, the negative electrode current collector plate 600 obstructs its movement.

[0093] In other words, if the negative electrode current collector plate 600 maintains its original position, the gas generated inside the battery can 200 is obstructed by the negative electrode current collector plate 600 and has difficulty being released, causing the internal pressure of the battery can 200 to increase. If the internal pressure of the battery can 200 is left unchecked, an explosion may occur in the cylindrical battery cell 10.

[0094] Therefore, in order to solve these problems, a cylindrical battery cell 10 according to one embodiment of the present invention is configured such that a fracture induction portion 700 is formed on the negative electrode current collector plate 600, and the negative electrode current collector plate 600 is fractured by the internal pressure of the battery can 200.

[0095] Referring to Figure 4, the negative electrode current collector plate 600 may be composed of a peripheral portion 610, a central portion 620, and a connecting portion 630. In Figure 4, the negative electrode current collector plate 600 is shown as an inverted version of the negative electrode current collector plate 600 in Figure 2. That is, in Figure 2, the central portion 620 is located above the peripheral portion 610, but in Figure 4, the central portion 620 is located below the peripheral portion 610. This is also true for Figures 5 to 11.

[0096] The peripheral portion 610 defines the periphery and may have a substantially rim shape with at least a portion of the inner region open. In Figure 4, the peripheral portion 610 is shown as having a substantially circular rim shape, but the shape of the peripheral portion 610 is not limited to this. The peripheral portion 610 may have a substantially square rim shape, a hexagonal rim shape, an octagonal rim shape, or other shapes, different from those shown. The peripheral portion 610 may be connected to the connecting portion 630.

[0097] The central part 620 is located inside the peripheral part 610 and is separated from the peripheral part 610. For example, the central part 620 may, but is not limited to, be located at the exact center of the inner space of the peripheral part 610. The central part 620 is connected to the connecting part 630, and the connecting part 630 connects it to the peripheral part 610. The central part 620 is then connected to the electrode assembly 100. Here, the central part 620 may be positioned in a location corresponding to the central hole 140 of the electrode assembly 100.

[0098] The connecting portion 630 connects the peripheral portion 610 and the central portion 620. Multiple connecting portions 630 may be provided, and the multiple connecting portions 630 may be spaced apart from each other. In Figure 4, four connecting portions 630 are provided, but the number of connecting portions 630 is not limited to this. Furthermore, the multiple connecting portions 630 may be arranged at equal intervals from each other, but is not limited to this.

[0099] Here, the fracture guide portion 700 can be formed in various locations, for example, on the connecting portion 630. In one embodiment, as shown in Figure 4, the fracture guide portion 700 can be formed on the connecting portion 630 at the point where the central portion 620 and the connecting portion 630 meet. However, the fracture guide portion 700 is not necessarily formed only at the point where the central portion 620 and the connecting portion 630 meet, but can be formed on any part of the connecting portion 630.

[0100] Referring to Figure 4, the fracture guide portion 700 may be formed as a groove, for example, a notch groove 710, in which the width of the connecting portion 630 narrows at the point where the central portion 620 and the connecting portion 630 meet. The notch groove 710 may be formed as a recess toward the inside of the connecting portion 630 in a direction that gradually or continuously reduces the width of the connecting portion 630 (left-right direction of the connecting portion 630). That is, the notch groove 710 may be formed in the width direction toward the inside from the outer end of the connecting portion 630. Here, the outer end of the connecting portion 630 is on the peripheral edge 610 side, and the inner end of the connecting portion 630 is on the central portion 620 side.

[0101] The notch groove 710 can have a variety of shapes. In Figure 4, it is formed in a triangular shape, but it is not limited to this and can be formed in a wider variety of shapes.

[0102] As shown in Figure 4, the fracture guide sections 700 are provided in pairs and may be formed on both ends of the connecting section 630. For example, there may be four connecting sections 630, and a total of eight notch grooves 710 may be formed in pairs on each connecting section 630, but this is not limited to this.

[0103] Thus, when a fracture-inducing portion 700 such as a notch groove 710 is formed in the connection portion 630, if the internal pressure of the battery can 200 increases, fracture occurs in the connection portion 630 along the notch groove 710, making it possible to easily remove the central portion 620 that is bonded to the electrode assembly 100.

[0104] Then, when the central hole 140 of the electrode assembly 100 is opened by removing the central part 620, the gas inside the battery can 200 moves from the central hole 140 towards the cap plate 230, causing the vent notch 231 formed in the cap plate 230 to burst. As a result, the gas inside the battery can 200 is easily released from the battery can 200.

[0105] Furthermore, the release of gas from inside the battery can 200 not only reduces the internal pressure of the cylindrical battery cell 10, but also prevents the cylindrical battery cell 10 from exploding.

[0106] Figures 5 to 10 are perspective views of the negative electrode current collector plate according to the modified embodiment of Figure 4, while Figure 11 is a perspective view showing the modified shape of the negative electrode current collector plate in Figure 10.

[0107] In the modified embodiments shown in Figures 5 to 11, the parts that are common to the parts described in the embodiment of Figure 4 will be described in the previously mentioned explanation. Also, the parts of the embodiment of Figure 4 that are applicable to the modified embodiments of Figures 5 to 11 can be applied to the modified embodiments of Figures 5 to 11.

[0108] Referring to Figure 5, the fracture guide portion 700 can be formed as a groove, for example, a notch groove 710, as shown in Figure 4. However, in Figure 4, it is formed as a groove in which the width (left-right direction) of the connecting portion 630 becomes narrower, whereas in Figure 5, it is formed as a groove in which the thickness (up-down direction) of the connecting portion 630 becomes thinner. That is, the notch groove 710 can be formed as a recess toward the inside of the connecting portion 630 in a direction that gradually or continuously reduces the thickness of the connecting portion 630.

[0109] Referring to Figure 5, the notched groove 710 can be formed on the upper and lower parts of the connecting portion 630 where the central portion 620 and the connecting portion 630 meet. In this way, even when the notched groove 710 is formed as a groove that reduces the thickness of the connecting portion 630, the connecting portion 630 can still be fractured along the notched groove 710 by the internal pressure of the battery can 200.

[0110] Referring to Figure 6, the fracture guide portion 700 may be formed in the 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 in the connecting portion 630 at the point where the central portion 620 and the connecting portion 630 meet.

[0111] The number of through-holes 720 can vary. For example, Figure 6 shows a case where there is one through-hole 720 in one connection part 630, but this is only one embodiment, and the number of through-holes 720 formed in one connection part 630 can be set in various ways.

[0112] Furthermore, the through-hole 720 can have a variety of shapes. For example, in Figure 6, a circular through-hole 720 is shown in the connecting portion 630, but this is only one embodiment, and the shape of the through-hole 720 can be various, such as elliptical, triangular, or quadrilateral.

[0113] In this way, when a through hole 720 is formed in the connection portion 630, the internal pressure of the battery can 200 makes it easier for the connection portion 630 to break.

[0114] Referring to Figure 7, the fracture guide section 700 has a circular through hole 720 with a further notched groove 710 formed within it. That is, a pair of triangular notched grooves 710 are formed outward from around the circular through hole 720. Here, the pair of notched grooves 710 can be formed facing in opposite directions. Here, the shapes of the through hole 720 and the notched grooves 710 can be formed in various ways.

[0115] Referring to Figure 8, the fracture guide portion 700 may be configured to include a twisted portion 730 formed by twisting the connecting portion 630. The twisted portion 730 may be formed by cutting the portion of the connecting portion 630 that connects with the peripheral portion 610, twisting it so that the opposite surface (bottom surface) is facing upward, and welding it to the peripheral portion 610.

[0116] Furthermore, when twisting the connecting portion 630 to join it to the peripheral portion 610, the degree of welding can be adjusted to induce fracture so that the fracture between the peripheral portion 610 and the connecting portion 630 is facilitated. Here, a cut or groove (for example, a notch groove) may be formed in the portion where the peripheral portion 610 and the twisted portion 730 come into contact, which may further facilitate the fracture between the peripheral portion 610 and the connecting portion 630.

[0117] For example, the twisted portion 730 may be composed of a first portion 731 and a second portion 732. The first portion 731 connects to the central portion 620. The second portion 732 is twisted and folded away from the first portion 731 and then connects to the peripheral portion 610.

[0118] In this way, when a twisted portion 730 is formed on the connection portion 630, the gas inside the battery can 200 moves and strikes the twisted portion 730, causing it to rotate. As the gas moves and rotates, energy consumption increases and the force is evenly distributed in all directions, resulting in a reduction in the explosive force caused by the gas.

[0119] Furthermore, when joining the connecting portion 630, which has a twisted portion 730 formed thereon, to the peripheral portion 610 by welding, the degree of welding can be adjusted, or a cut or groove (for example, a notch groove) can be formed to facilitate the fracture of the peripheral portion 610 and the connecting portion 630 by gas.

[0120] In other words, the embodiment shown in Figure 8 facilitates gas discharge by making it easy to break the peripheral portion 610 and the connecting portion 630 provided on the negative electrode current collector plate 600. This not only prevents internal pressure and explosion, but also reduces the explosive force caused by the gas by consuming the gas energy through the rotation of the gas by the twisted portion 730 and distributing the force uniformly.

[0121] Figure 9 shows a modified embodiment of Figure 8, in which the twisted portion 730 is formed in a curved shape to rotate the gas. The twisted portion 730 can have a variety of curved surfaces. For example, referring to Figure 9, the twisted portion 730 may be configured such that the connecting portion 630 rotates 180° from the central portion 620 and connects to the peripheral portion 610.

[0122] Then, as shown in Figure 9, a notch groove 710 can be formed in the second part 732 of the twisted portion 730.

[0123] The embodiment in Figure 9 offers a more advantageous gas rotation than the embodiment in Figure 8. However, the embodiments in Figure 8 and Figure 9 can be appropriately selected as needed.

[0124] Note that a detailed explanation of the embodiment shown in Figure 9 may be replaced by the section described in Figure 8.

[0125] Referring to Figure 10, the fracture guide portion 700 is formed in a groove, for example, a notched groove 710. It is formed as a groove in which the thickness (vertical direction) of the connecting portion 630 becomes thinner. However, in Figure 5, a pair of notched grooves 710 are provided and formed on both the upper and lower parts of the connecting portion 630, whereas in Figure 10, the notched groove 710 is formed only on the upper part of the connecting portion 630, which is a difference.

[0126] As shown in Figure 10, if the notch groove 710 is formed only on the upper part of the connection portion 630, the gas inside the battery can 200 causes the central part 620 of the negative electrode current collector plate 600 to move in the opposite direction (see arrow in Figure 11), as shown in Figure 11. When the central part 620 is deformed in the opposite direction in this way, it becomes easier to expel the gas inside the battery can 200. However, if gas continues to be generated after the central part 620 has been deformed in the opposite direction, eventually a fracture will occur between the central part 620 and the connection portion 630. Of course, in the embodiment of Figure 5, as in Figure 10, the central part 620 of the negative electrode current collector plate 600 can be deformed in the opposite direction by the gas inside the battery can 200.

[0127] Figure 12 is a schematic diagram showing the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention.

[0128] Referring to Figure 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. The battery pack 20 may further include a battery can 200 for housing the cylindrical battery cells 10, and various devices for controlling the charging and discharging of the cylindrical battery cells 10, such as a BMS, current sensor, fuse, etc.

[0129] Figure 13 is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention.

[0130] Referring to Figure 13, an automobile 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 embodiments described above. Here, the automobile 30 includes various types of automobiles that use electricity, such as electric vehicles or hybrid vehicles.

[0131] In this specification, terms indicating direction such as up, down, left, right, front, and back are used. However, it is obvious to those skilled in the art that such terms indicate relative positions and are used only for the sake of convenience, and that these positions can change depending on the position of the object in question, the observer's position, and so on.

[0132] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and of course, various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims below by persons with ordinary skill in the art to which the present invention pertains. Therefore, the embodiments described above should be considered from an explanatory rather than restrictive viewpoint. That is, the true technical concept of the present invention is shown in the claims, and all differences within the equivalent scope thereto should be interpreted as being included in the present invention. [Industrial applicability]

[0133] The present invention relates to cylindrical battery cells, battery packs and automobiles containing them, and current collector plates, and is particularly applicable to the secondary battery industry. [Explanation of symbols]

[0134] 10 cylindrical battery cells 20 Battery Packs 30 automobiles 100 electrode assembly 110 Positive plate 111 First unmounted section 120 Negative plate 121 Second uncoated area 130 Separation membrane 140 Center hole 180 Center 200 Battery Can 210 Closing part 211 Through hole 220 Open area 230 Cap Plate 231 Bent Notch 240 Beading section 250 Crimping section 260 Sealing Gasket 300 Positive electrode current collector plate 400 cell terminals 500 Insulators 600 Negative electrode current collector plate 610 Peripheral area 620 Center 630 Connection part 700 Fracture induction section 710 Notch groove 720 Through hole 730 Twisted section 731 Part 1 732 Part 2

Claims

1. An electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separation membrane interposed between the positive electrode plate and the negative electrode plate are wound in one direction, A cylindrical battery can containing the electrode assembly and having a through hole formed therein, 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 a through-hole in the battery can, A negative electrode current collector plate electrically connected to the aforementioned negative electrode plate, A cylindrical battery cell comprising, A cylindrical battery cell characterized in that a fracture-inducing portion is formed on the positive electrode current collector plate or the negative electrode current collector plate such that at least a part of the positive electrode current collector plate or the negative electrode current collector plate fractures due to gas generated inside the battery can.

2. The positive electrode current collector plate or the negative electrode current collector plate is The peripheral part that defines the periphery, A central part that is separated from the peripheral part and coupled to the electrode assembly, A cylindrical battery cell according to claim 1, characterized by including a connecting portion that connects the peripheral portion and the central portion.

3. The fracture induction portion is The cylindrical battery cell according to claim 2, characterized in that it is formed in the connection portion.

4. The fracture induction section is The cylindrical battery cell according to claim 2, characterized in that it is formed on the connection portion at the point where the central portion and the connection portion come into contact.

5. The cylindrical battery cell according to claim 1, characterized in that the fracture induction portion is formed as a notch groove.

6. The cylindrical battery cell according to claim 1, characterized in that the fracture induction portion is formed as a through hole.

7. The aforementioned connection part consists of four parts. The cylindrical battery cell according to claims 2 and 5, characterized in that a total of eight notch grooves are formed in pairs at each connection portion.

8. The cylindrical battery cell according to claims 2 and 5, characterized in that the notch groove is formed to be recessed toward the inside of the connection portion in a direction in which the width or thickness of the connection portion decreases in a stepwise or continuous manner.

9. The cylindrical battery cell according to claim 2, characterized in that the fracture induction portion includes a torsion portion formed by twisting the connection portion.

10. The aforementioned twisted portion is, The first part connected to the central part, A cylindrical battery cell according to claim 9, characterized by comprising: a second part which is twisted and folded from the first part and then joined to the peripheral edge.

11. The cylindrical battery cell according to claim 9, characterized in that the twisted portion is formed in a curved shape to rotate the gas.

12. The cylindrical battery cell according to claim 11, characterized in that the twisted portion is configured such that the connecting portion rotates 180° from the central part and connects to the peripheral part.

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

14. An automobile comprising at least one cylindrical battery cell as described in any one of claims 1 to 12.

15. In a cylindrical battery cell, a current collector plate electrically connects an electrode assembly located in a portion where a vent is formed, The peripheral part that defines the periphery, A central part that is separated from the peripheral part and coupled to the electrode assembly, It includes a connecting portion that connects the peripheral portion and the central portion, A current collector plate characterized in that a fracture-inducing portion is formed on the current collector plate such that at least a part of the current collector plate is fractured by gas generated in the cylindrical battery cell.

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