Cap plate, battery cell, battery pack comprising same, and vehicle

Abstract

Disclosed are a cap plate, a battery cell, a battery pack comprising same, and a vehicle. A cap plate according to one embodiment of the present invention is a cap plate coupled to a battery can, the cap plate comprising: a main body part for sealing the battery can; a vent notch part which is formed in the main body part and ruptures when the pressure inside the battery can exceeds a threshold value; and a fracture induction part spaced apart from the vent notch part and formed in the main body part so that the vent notch part can be fractured at a preset position.

Description

Cap plate, battery cell and battery pack including the same and automobile

[0001] This application is a priority application for Korean Patent Application No. 10-2024-0184960 filed on December 12, 2024, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0002] The present invention relates to a cap plate, a battery cell, a battery pack including the same, and an automobile, and more specifically, to a cap plate, a battery cell, a battery pack including the same, and an automobile that is easily broken upon a thermal event.

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

[0004] These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, as they not only have the primary advantage of being able to drastically reduce the use of fossil fuels but also the advantage of not generating any by-products from the use of energy.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells is approximately 2.5V to 4.5V.

[0006] Therefore, if a higher output voltage is required, a battery module or battery pack is configured by connecting multiple battery cells in series. Additionally, a battery module or battery pack is configured by connecting multiple battery cells in parallel depending on the required charge / discharge capacity. Accordingly, the number of battery cells included in the battery module or battery pack and the electrical connection type can be varied according to at least one of the required output voltage and charge / discharge capacity.

[0007] Meanwhile, cylindrical, prismatic, and pouch-type battery cells are known as types of secondary battery cells. In the case of a cylindrical battery cell, an insulating separator is interposed between a positive plate and a negative plate, and this is wound to form a jellyroll-shaped electrode assembly, which is then inserted into a battery can along with an electrolyte to constitute a battery.

[0008] FIG. 1 is a perspective view of a conventional cap plate. The cap plate is coupled to the battery can of a cylindrical battery cell.

[0009] Referring to FIG. 1, a vent notch (2) is formed in the cap plate (1), and the vent notch (2) is configured to rupture when the pressure inside the battery can exceeds a critical value. In FIG. 1, the battery can is omitted and only the cap plate (1) is shown.

[0010] Although the thinner the thickness of the vent notch (2) in the cap plate (1), the easier it is to break in the event of a thermal event, there is a limit to how thin the thickness of the vent notch (2) can be reduced through processing.

[0011] In addition, if the thickness of the vent notch portion (2) in the cap plate (1) becomes thinner than a certain level, there is a problem in that the electrolyte, gas, etc. leak out due to cracks during the activation process of the battery cell.

[0012] Accordingly, the technical problem to be solved by the present invention is to provide a cap plate, a battery cell, a battery pack including the same, and an automobile, wherein the vent notch portion can be easily fractured through a fracture-inducing portion even if the thickness of the vent notch portion is formed thicker than a certain level.

[0013] In addition, the invention provides a cap plate, a battery cell, a battery pack including the same, and an automobile capable of specifying a location among the vent notch portions where fracture and venting may occur.

[0014] In addition, it provides a cap plate, a battery cell, a battery pack containing the same, and an automobile, which have improved mass production capabilities and are easy to manage.

[0015] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below.

[0016] According to one aspect of the present invention, a cap plate is provided that is coupled to a battery can, the cap plate comprising: a main body portion that seals the battery can; a vent notch portion formed on the main body portion that ruptures when the pressure inside the battery can exceeds a critical value; and a rupture-inducing portion formed on the main body portion that is spaced apart from the vent notch portion and allows the vent notch portion to rupture at a preset position.

[0017] In one embodiment, at least one stiffness-increasing portion is formed in the main body, and a fracture-inducing portion may be formed between a plurality of stiffness-increasing portions.

[0018] In one embodiment, the rigidity enhancing portion may be composed of an indentation groove formed in an intaglio shape on the main body portion inside the vent notch portion.

[0019] In one embodiment, three insertion grooves are formed, and one fracture-inducing member may be formed between two of the three insertion grooves.

[0020] In one embodiment, three fracture-inducing sections are formed, and at the portion where the three fracture-inducing sections meet, a central section connected in a straight line to the fracture-inducing sections may be formed.

[0021] In one embodiment, each of the three fracture-inducing parts may be spaced apart by 120 degrees from each other.

[0022] In one embodiment, the rigidity-increasing portion may include a first portion formed on the inner side of the vent notch portion; a second portion extending from one side of the first portion toward the inner side of the main body portion; a third portion extending from the other side of the first portion toward the inner side of the main body portion; and a fourth portion connecting the second portion and the third portion.

[0023] In one embodiment, the vent notch portion includes a curve, and the first portion may have a curve parallel to a part of the curve of the vent notch portion.

[0024] In one embodiment, the second part and the third part may be formed in a straight line shape.

[0025] In one embodiment, the virtual extension line of the second part and the virtual extension line of the third part may be formed to meet each other.

[0026] In one embodiment, the fourth part may have a curve parallel to a part of the curve of the first part.

[0027] According to one aspect of the present invention, a battery cell may be provided, comprising: an electrode assembly including a positive plate, a negative plate, and a separator interposed between the positive plate and the negative plate; a battery can having an opening and a closing portion, in which the electrode assembly is housed; and a cap plate configured to seal the opening portion of the battery can.

[0028] In one embodiment, the battery can includes a sealing gasket interposed between the edge of the cap plate and the opening of the battery can, and the battery can may include a beading portion formed such that the outer circumference of the battery can is pressed inward; and a clamping portion that extends inwardly and is bent to wrap around and secure the edge of the cap plate together with the sealing gasket.

[0029] Meanwhile, according to another aspect of the present invention, a battery pack comprising at least one of the aforementioned battery cells may be provided, and a vehicle comprising at least one of the aforementioned battery cells may also be provided.

[0030] The embodiments of the present invention have the effect that even if the thickness of the vent notch is formed thicker than a certain level, the vent notch can be easily fractured through the fracture inducing portion.

[0031] In addition, it has the effect of identifying locations within the vent notch where fracture and venting may occur.

[0032] In addition, it has the effect of improving mass production capabilities and making management easier.

[0033] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0034] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0035] Figure 1 is a perspective view of a conventional cap plate.

[0036] FIG. 2 is a perspective view of a cap plate according to one embodiment of the present invention.

[0037] FIG. 3 is a perspective view showing a cross-section along A-A' of FIG. 2.

[0038] Figure 4 is a cross-sectional view taken along A-A' of Figure 2.

[0039] FIG. 5 is a perspective view showing a cross-section along B-B' of FIG. 2.

[0040] Figure 6 is a cross-sectional view taken along B-B' of Figure 2.

[0041] FIG. 7 is a cross-sectional view of a battery cell according to one embodiment of the present invention, in which a cap plate according to each embodiment of the present invention is combined.

[0042] FIG. 8 is a drawing illustrating a battery can in a battery cell according to one embodiment of the present invention.

[0043] Figure 9 is a graph showing the correlation of venting pressure according to the thickness of the vent notch portion in a cap plate according to one embodiment of the present invention.

[0044] FIG. 10 is a graph showing the correlation of venting pressure according to the thickness of the vent notch portion in a battery cell including a cap plate according to one embodiment of the present invention.

[0045] FIG. 11 is a graph showing the change in the center of a cap plate when venting pressure is applied to a cap plate according to one embodiment of the present invention.

[0046] FIG. 12 is a graph showing the change in the outer diameter of a cap plate when a venting pressure is applied to the cap plate according to one embodiment of the present invention.

[0047] FIG. 13 is a schematic diagram showing the configuration of a battery pack including a battery cell according to each embodiment of the present invention.

[0048] FIG. 14 is a drawing for explaining a vehicle including the battery pack of FIG. 13.

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely one preferred embodiment of the present invention and do not represent all aspects of the technical spirit of the present invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0050] In the drawings, the size of each component or specific part constituting the component is exaggerated, omitted, or schematically depicted for convenience and clarity of explanation. Accordingly, the size of each component does not entirely reflect its actual size. If it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the invention, such description shall be omitted.

[0051] As used in this specification, the terms "combination" or "connection" include not only cases where one member and another member are directly joined or directly connected, but also cases where one member is indirectly joined or indirectly connected to another member through a connecting member.

[0052] FIG. 2 is a perspective view of a cap plate according to an embodiment of the present invention, FIG. 3 is a perspective view showing a cross-section along A-A' of FIG. 2, FIG. 4 is a cross-sectional view taken along A-A' of FIG. 2, FIG. 5 is a perspective view showing a cross-section taken along B-B' of FIG. 2, and FIG. 6 is a cross-sectional view taken along B-B' of FIG. 2.

[0053] Referring to FIG. 2, a cap plate (10) according to one embodiment of the present invention is a cap plate (10) coupled to a battery can (210), and includes a main body part (100), a vent notch part (110), and a breakage induction part (120).

[0054] The main body (100) is coupled to the battery can (210) of the battery cell (20) and seals the battery can (210). Referring to FIGS. 7 and 8, when an opening (211) and a closing (212) are formed in the battery can (210) of the battery cell (20), the main body (100) is configured to seal the opening (211) of the battery can (210).

[0055] A sealing gasket (220) may be attached to the edge of the main body (100) to ensure airtightness of the battery can (210).

[0056] A vent notch (110) is formed in the main body (100) so that it ruptures in the event of a thermal event, thereby allowing gas inside the battery can (210) to be discharged. Here, the vent notch (110) is formed as an area having a thinner thickness compared to the surrounding area of ​​the main body (100) and is configured to rupture when the pressure inside the battery can (210) exceeds a critical threshold.

[0057] Since the vent notch (110) is thinner than the surrounding area, it can be broken more easily than the surrounding area, and if the internal pressure of the battery can (210) increases above a certain level, the vent notch (110) can be broken so that the gas generated inside the battery can (210) can be discharged. For example, the vent notch (110) can be formed through notching.

[0058] The vent notch portion (110) may have various shapes. For example, the vent notch may be formed on the surface of the cap plate (10) in at least one of a continuous circular pattern, a discontinuous circular pattern, and a straight pattern. Additionally, the vent notch may be formed in various other patterns.

[0059] Here, the vent notch portion (110) can be formed in various shapes including curves, and for example, as shown in FIG. 2, it may be circular, but the shape of the vent notch portion (110) is not limited thereto. However, for convenience of explanation, the following description will focus on the case where the vent notch portion (110) is formed in a circular shape.

[0060] The fracture-inducing portion (120) is formed on the main body portion (100) spaced apart from the vent notch portion (110). The location of the fracture-inducing portion (120) can vary; for example, it may be formed inside the vent notch portion (110), but is not limited thereto. However, for convenience of explanation, the following description will focus on the case where the fracture-inducing portion (120) is formed inside the vent notch portion (110).

[0061] Here, the inner and outer sides are based on the diameter direction of the cap plate (10). That is, based on the diameter direction, the side where the diameter increases from the center of the cap plate (10) is the outer side, and the side where the diameter decreases is the inner side.

[0062] A fracture-inducing portion (120) is formed in the main body (100) so that the vent notch portion (110) can be easily fractured at a preset position.

[0063] As in the conventional cap plate of Fig. 1, when the vent notch is formed as a circular shape with the same thickness, there is a problem in that it is impossible to predict which part of the vent notch will break when the pressure inside the battery can rises during a thermal event. That is, breakage occurs at any part of the vent notch, and since the point of breakage cannot be accurately predicted, there is a problem of reducing the ease of venting gas.

[0064] To solve the problems of the conventional technology, a fracture-inducing portion (120) is formed in the cap plate (10) according to one embodiment of the present invention. That is, when the pressure inside the battery can (210) increases, fracture can easily occur at the vent notch portion (110) at the location where the fracture-inducing portion (120) is formed. Accordingly, it can be designed so that fracture occurs at the vent notch portion (110) at a preset location.

[0065] Additionally, referring to FIGS. 9 and 10 described later, a vent notch (110) having a thicker thickness based on the same venting pressure can be formed on the cap plate (10) to prevent cracking of the cap plate (10).

[0066] Referring to FIGS. 2 to 4, at least one rigidity-enhancing portion (101) may be formed in the main body portion (100). The rigidity-enhancing portion (101) may be formed in various ways, for example, by an indentation groove (102) formed in an intaglio shape in the main body portion (100) on the inner side of the vent notch portion (110).

[0067] In this way, when an insertion groove (102) is formed in the main body (100), the rigidity against bending (bending rigidity) increases in the insertion groove (102) portion.

[0068] To explain this, when an indentation groove (102) is formed in the main body (100), the second moment of area changes due to a change in the cross-sectional shape. That is, when the indentation groove (102) is formed, the material is relocated to an area far from the neutral axis, and the second moment of area increases. Since bending stiffness is proportional to the second moment of area, when the indentation groove (102) is formed in the main body (100), both the second moment of area and the bending stiffness increase.

[0069] Accordingly, the part of the main body (100) in which the insertion groove (102) is formed has increased bending rigidity compared to the part in which the insertion groove (102) is not formed, so it can act as a rigidity-increasing part (101).

[0070] Referring to FIGS. 2, FIGS. 3 and FIGS. 5, the insertion groove (102) may include a first part (103), a second part (104), a third part (105), and a fourth part (106).

[0071] The first part (103) is formed on the inner side of the vent notch portion (110). The first part (103) can be formed in various shapes. For example, as described above, focusing on the case where the vent notch portion (110) is circular among various shapes including curves, it can be formed to have a curve parallel to a part of the curve of the vent notch portion (110). However, the shape of the first part (103) is not limited to this.

[0072] The fact that a part of the curve of the vent notch portion (110) and the curve of the first portion (103) are parallel means that a part of the vent notch portion (110) is also formed as a curve and the first portion (103) is also formed as a curve, but they do not meet each other. However, this is merely one embodiment, and it is acceptable for a part of the curve of the vent notch portion (110) and the curve of the first portion (103) not to be parallel.

[0073] The second part (104) extends from one side of the first part (103) toward the inside of the main body part (100). Here, the second part (104) may be formed in a straight shape.

[0074] The third part (105) extends from the other side of the first part (103) toward the inside of the main body part (100). Here, the third part (105) may be formed in a straight shape.

[0075] And, the virtual extension line of the second part (104) and the virtual extension line of the third part (105) can be formed to meet each other. That is, it means that the second part (104) and the third part (105) are not parallel.

[0076] The fourth part (106) is configured to connect the second part (104) and the third part (105). The fourth part (106) may have various shapes, for example, it may be configured to have a curve parallel to a part of the curve of the first part (103), but is not limited thereto.

[0077] Referring to FIG. 2, the fracture-inducing portion (120) may be formed between a plurality of rigidity-increasing portions (101), that is, a plurality of internal grooves (102). The fracture-inducing portion (120) does not cause fracture itself, but rather induces fracture to occur at the vent notch portion (110) located close to the portion where the fracture-inducing portion (120) is formed.

[0078] As described above, when an insertion groove (102) is formed in the main body (100), the bending rigidity is increased in the insertion groove (102) compared to the fracture-inducing part (120) where the insertion groove (102) is not formed, so it is difficult for a fracture to occur in the vent notch part (110) located close to the part where the insertion groove (102) is formed.

[0079] That is, even if the thickness of the vent notch portions (110) are all formed equally and the same pressure is applied to the vent notch portions (110), the vent notch portions (110) formed in a position adjacent to the insertion groove (102), where the bending rigidity is increased and deformation does not easily occur, are unlikely to break, whereas the vent notch portions (110) formed in a position adjacent to the breakage-inducing portion (120) formed between the insertion grooves (102) are relatively likely to break.

[0080] Accordingly, even if the thickness of the vent notch portion (110) is formed to be thicker than a certain level, the vent notch portion (110) can be easily broken through the fracture inducing portion (120).

[0081] Additionally, the fracture inducing portion (120) induces fracture to occur in the vent notch portion (110) located adjacent to the fracture inducing portion (120), thereby having the effect of specifying the location in the vent notch portion (110) where venting may occur.

[0082] In this way, when the venting position of the venter notch is specified, it is possible to vent gas or the like in a certain direction, which is advantageous in the design of the battery cell (20), and also has the effect of improving mass production and making management easier.

[0083] Referring to FIG. 2, three indentation grooves (102) may be formed. However, the number of indentation grooves (102) may vary, and the formation of three indentation grooves (102) is merely one embodiment. However, for convenience of explanation, the following description will focus on the case where there are three indentation grooves (102).

[0084] And, a fracture-inducing portion (120) may be formed between two of the three insertion grooves (102).

[0085] Referring to FIG. 2, three fracture-inducing sections (120) may be formed. However, the number of fracture-inducing sections (120) may vary, and the formation of three fracture-inducing sections (120) is merely one embodiment. However, for convenience of explanation, the following description will focus on the case where there are three fracture-inducing sections (120).

[0086] Referring to FIG. 2, a center (130) may be formed at the point where three fracture-inducing sections (120) meet. Also, referring to FIG. 5 and FIG. 6 together, the fracture-inducing sections (120) and the center (130) may be connected by a straight line. That is, the fracture-inducing sections (120) and the center (130) are located on the same straight line, and the insertion groove (102) is formed to go inward from the fracture-inducing sections (120) and the center (130). Here, the insertion groove (102) may be formed by press processing, etc.

[0087] And, referring again to FIG. 2, each of the three fracture-inducing sections (120) may be spaced apart from each other by 120 degrees. However, it is not limited to this.

[0088] FIG. 7 is a cross-sectional view of a battery cell according to one embodiment of the present invention in which a cap plate according to each embodiment of the present invention is combined, and FIG. 8 is a drawing showing a battery can in a battery cell according to one embodiment of the present invention.

[0089] Referring to FIG. 7, a battery cell (20) according to one embodiment of the present invention includes an electrode assembly (200), a battery can (210), and a cap plate (10).

[0090] The electrode assembly (200) includes an anode plate, a cathode plate, and a separator interposed between the anode plate and the cathode plate, and the anode plate, the cathode plate, and the separator may have a structure wound in one direction. In addition, a center hole (201) is formed in the center of the electrode assembly (200), and it may be formed in a jelly roll type.

[0091] For example, the electrode assembly (200) can be manufactured by winding a laminate formed by sequentially stacking a cathode plate, a separator, an anode plate, and a separator at least once. Here, the anode plate and the cathode plate may be formed in a sheet shape.

[0092] That is, the electrode assembly (200) applied in this embodiment may be a wound-type electrode assembly (200). In this case, an additional separator may be provided on the outer surface of the electrode assembly (200) to insulate it from the battery can (210). That is, the electrode assembly (200) may have a wound structure well known in the relevant technical field without limitation.

[0093] A positive active material is coated on one or both sides of the positive plate, and a first uncoated portion, on which the positive active material is not coated, may be formed at the end of the positive plate. The first uncoated portion may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (200), and may be used as an electrode tab itself. However, the first uncoated portion may not be formed on the positive plate.

[0094] A negative electrode active material is coated on one or both sides of the negative electrode plate, and a second uncoated portion, on which the negative electrode active material is not coated, may be formed at the end of the negative electrode plate. The second uncoated portion may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (200), and may be used as an electrode tab itself. However, the second uncoated portion may not be formed on the negative electrode plate.

[0095] Here, when the positive plate and the negative plate each include a non-existent portion, the first non-existent portion and the second non-existent portion may be configured to face in opposite directions.

[0096] In addition, the positive active material coated on the positive plate and the negative active material coated on the negative plate may be used without limitation as long as they are active materials known in the art.

[0097] The separator can be a porous polymer film made of a polyolefin-based polymer, such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., used alone or by laminating them.

[0098] As another example, the separation membrane may use a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0099] At least one surface of the separation membrane may include a coating layer of inorganic particles. It is also possible for the separation membrane itself to consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded with a binder such that interstitial volume exists between adjacent particles.

[0100] Additionally, the center hole (201) of the electrode assembly (200) is also used for welding the cell terminal (240, positive terminal) and the positive current collector plate (230). That is, it can be configured to weld the cell terminal (240) and the positive current collector plate (230) by irradiating a laser through the center hole (201) of the electrode assembly (200).

[0101] An electrode assembly (200) is housed in a battery can (210). For example, the battery can (210) is formed in a cylindrical shape so that the electrode assembly (200) is housed inside the battery can (210) and can be electrically connected to the negative plate of the electrode assembly (200). Accordingly, the battery can (210) can have the same polarity as the negative plate, that is, a negative electrode.

[0102] Referring to FIG. 8, a closed portion (212) and an open portion (211) may be formed in the battery can (210) so as to be positioned opposite each other.

[0103] For example, based on FIG. 8, an opening (211) may be formed at the top of the battery can (210). The battery can (210) accommodates an electrode assembly (200) through the opening (211) formed at the top, and an electrolyte may also be injected through the opening (211) formed at the top of the battery can (210). However, the opening (211) of the battery can (210) may also be formed at the bottom.

[0104] That is, the battery can (210) is a roughly cylindrical receptacle with an opening (211) formed at the top, and is made of a conductive material such as, for example, metal. The material of the battery can (210) may be a conductive metal, for example, aluminum, steel, stainless steel, etc., but is not limited thereto. A Ni coating layer may optionally be formed on the surface of the battery can (210).

[0105] Additionally, based on FIG. 8, a closure (212) may be formed at the bottom of the battery can (210). A through hole (215) is formed in the closure (212), and a cell terminal (240) may be coupled to the through hole (215) as in FIG. 7.

[0106] The diameter of the battery can (210) is formed to be larger than the diameter of the electrode assembly (200). A gap of a predetermined size is formed between the battery can (210) and the positive current collector plate (230), and an insulator (250) may be interposed between the gaps.

[0107] If the size of the electrode assembly (200) is increased while the size of the battery can (210) is determined according to the specifications, the total capacity of the battery cell (20) increases, but the gap between the battery can (210) and the electrode assembly (200) decreases.

[0108] That is, to increase the total capacity of the battery cell (20), the size of the electrode assembly (200) is increased, and thus the gap between the battery can (210) and the electrode assembly (200) is reduced. Therefore, to increase the capacity of the battery cell (20), an insulator (250) must be interposed in the reduced gap between the battery can (210) and the electrode assembly (200), and for this purpose, it is desirable that the thickness of the insulator (250) be as thin as possible.

[0109] The battery can (210) is a roughly cylindrical receptacle and may be made of a conductive material, such as metal. The material of the battery can (210) may be made of a conductive metal, such as aluminum, steel, stainless steel, etc., but is not limited thereto.

[0110] The cap plate (10) is a cap plate (10) including a fracture-inducing portion (120) according to each of the embodiments described above, as described above.

[0111] The cap plate (10) is coupled to the battery can (210) and configured to seal the opening (211) formed in the battery can (210). The cap plate (10) may be made of, for example, a metal material to ensure rigidity.

[0112] Additionally, the cap plate (10) can be separated from the electrode assembly (200) and provided as non-polar. That is, even if the cap plate (10) is made of a conductive metal material, it may not have polarity.

[0113] The fact that the cap plate (10) does not have polarity means that the cap plate (10) is electrically insulated from the battery can (210) and the cell terminal (240). As such, the cap plate (10) does not need to have polarity, and its material does not necessarily have to be a conductive metal.

[0114] The cap plate (10) can be seated and supported on the beading portion (213) formed on the battery can (210). Additionally, the cap plate (10) can be secured by the clamping portion (214). A sealing gasket (220) may be interposed between the cap plate (10) and the clamping portion (214) of the battery can (210) to ensure airtightness of the battery can (210). That is, the sealing gasket (220) may be provided to be interposed between the edge of the cap plate (10) and the opening (211) of the battery can (210).

[0115] And, a vent notch (110) that bursts due to internal pressure of the battery can (210) may be formed in the cap plate (10), as described above.

[0116] A beading portion (213) and a crimping portion (214) can be formed in the battery can (210).

[0117] The beading portion (213) is formed so that the outer circumference of the battery can (210) is pressed inward. The beading portion (213) supports the electrode assembly (200) so that the electrode assembly (200), which has a size approximately corresponding to the width of the battery can (210), does not come out of the battery can (210), and can also function as a support for the cap plate (10) to be seated. In addition, the beading portion (213) can support the outer surface of the sealing gasket (220).

[0118] The crimping portion (214) is extended and bent inward toward the battery can (210) to wrap around and secure the edge of the cap plate (10) together with the sealing gasket (220). Additionally, the crimping portion (214) may be formed on the upper part of the beading portion (213) based on FIG. 7, as shown in FIG. 7. However, this is merely one embodiment, and the positions of the crimping portion (214) and the beading portion (213) are not limited thereto.

[0119] When the clamping portion (214) is formed on the upper part of the beading portion (213) based on FIG. 7, the clamping portion (214) has an extended and bent shape that wraps around the edge of the cap plate (10) placed on the upper part of the beading portion (213). Due to the shape of this folded clamping portion (214), the cap plate (10) can be fixed on the beading portion (213).

[0120] The positive current collector plate (230) is electrically connected to the positive plate of the electrode assembly (200). For example, the positive current collector plate (230) may be made of a conductive metal material and may be electrically connected to the first non-conductive portion of the positive plate.

[0121] The cell terminal (240) is made of a conductive metal material and is electrically connected to the positive current collector plate (230). The cell terminal (240) is electrically connected to the positive plate of the electrode assembly (200) through the positive current collector plate (230) and thereby has a positive polarity.

[0122] That is, the cell terminal (240) can function as a positive terminal. Also, the battery can (210) is electrically connected to the negative plate of the electrode assembly (200) as described above, and thereby can have a negative polarity.

[0123] The negative electrode collector plate (260) is electrically connected to the negative electrode plate of the electrode assembly (200). For example, the negative electrode collector plate (260) is made of a conductive metal material such as aluminum, steel, copper, or nickel, and can be electrically connected to the second non-conductive portion of the negative electrode plate.

[0124] The negative electrode collector plate (260) can be fixed by interposing at least a portion of its edge portion between the inner surface of the battery can (210) and the sealing gasket (220).

[0125] FIG. 9 is a graph showing the correlation of venting pressure according to the thickness of the vent notch portion in a cap plate according to one embodiment of the present invention, and FIG. 10 is a graph showing the correlation of venting pressure according to the thickness of the vent notch portion in a battery cell including a cap plate according to one embodiment of the present invention.

[0126] FIG. 9 is a graph showing the venting pressure measured using only a cap plate (10) with a vent notch (110) formed therein. Here, the comparative example is the conventional cap plate (10) of FIG. 1, and the embodiment of the present invention is the cap plate (10) according to one embodiment of the present invention of FIG. 2.

[0127] And, FIG. 10 is a graph measuring the venting pressure of a battery cell (20) coupled to a battery can (210) with a cap plate (10) having a vent notch (110) formed therein. Here, the comparative example is a battery cell (20) coupled with a conventional cap plate (10) of FIG. 1, and the embodiment of the present invention is a battery cell (20) coupled with a cap plate (10) according to one embodiment of the present invention of FIG. 2.

[0128] That is, in FIG. 9, the change in venting pressure according to the thickness of the vent notch portion (110) of the cap plate (10) of FIG. 1 and the cap plate (10) of FIG. 2 is shown as a graph, and in FIG. 10, the change in venting pressure according to the thickness of the vent notch portion (110) of each cap plate (10) in the battery cell (20) combined with the cap plate (10) of FIG. 1 and the battery cell (20) combined with the cap plate (10) of FIG. 2 is shown as a graph.

[0129] Referring to FIG. 9 and FIG. 10 together, it can be seen that when the same venting pressure is applied in both FIG. 9 and FIG. 10, the thickness of the vent notch portion (110) of the embodiment of the present invention is thicker than the thickness of the vent notch portion (110) of the comparative example.

[0130] For example, in FIG. 9, when the venting pressure is 30 [kgf / cm2], the thickness of the vent notch portion (110) of the comparative example is approximately 87.5 [μm], but the thickness of the vent notch portion (110) of the embodiment of the present invention is approximately 102 [μm]. Also, in FIG. 10, when the venting pressure is 30 [kgf / cm2], the thickness of the vent notch portion (110) of the comparative example is approximately 84 [μm], but the thickness of the vent notch portion (110) of the embodiment of the present invention is approximately 102 [μm].

[0131] As described above in the background technology of the invention, if the thickness of the vent notch portion (110) is reduced to a certain level or less, there is a problem in that the electrolyte, gas, etc. leak out due to cracks during the activation process of the battery cell.

[0132] However, in the case of an embodiment of the present invention, referring to FIG. 9 and FIG. 10, a vent notch portion (110) having a thicker thickness based on the same venting pressure can be formed on the cap plate (10), so that cracking of the cap plate (10) can be prevented.

[0133] In addition, since it is not sensitive to the thickness of the vent notch portion (110), it is easy to ensure thickness variation of the vent notch portion (110), and even if the thickness of the vent notch portion (110) is not uniform due to processing errors, etc., fracture can easily occur in the vent notch portion (110) of a preset part.

[0134] FIG. 11 is a graph showing the change in the center of a cap plate when venting pressure is applied to a cap plate according to one embodiment of the present invention.

[0135] Here, the comparative example is the conventional cap plate (10) of FIG. 1, and the embodiment of the present invention is the cap plate (10) according to one embodiment of the present invention of FIG. 2.

[0136] Referring to FIG. 11, when venting pressure is applied to the cap plate (10), the amount of change in the center (130) of the cap plate (10) according to one embodiment of the present invention is smaller than the amount of change in the center (130) of the cap plate (10) of the comparative example.

[0137] That is, since the amount of change in the center (130) of the cap plate (10) is small, even if a thermal event occurs and the pressure inside the battery can (210) exceeds a critical value, the deformation of the battery cell (20) in the height direction is suppressed.

[0138] FIG. 12 is a graph showing the change in the outer diameter of a cap plate when a venting pressure is applied to the cap plate according to one embodiment of the present invention.

[0139] The change in the outer diameter of the cap plate (10) shown in the graph in FIG. 12 is the value obtained by subtracting the initial outer diameter from the outer diameter after the change, and since the outer diameter of the cap plate (10) decreased when the venting pressure was applied, the amount of change is indicated as a negative number (minus).

[0140] Referring to FIG. 12, the amount of change in the outer diameter of the cap plate (10) according to one embodiment of the present invention is smaller than the amount of change in the outer diameter of the cap plate (10) of the comparative example.

[0141] As described above, when the cap plate (10) is fixed by the clamping part (214), if the outer diameter of the cap plate (10) shrinks, a gap may form between the cap plate (10) and the clamping part (214), and gas may be discharged through the clamping part (214), which may cause a problem with the stability of the battery cell (20).

[0142] However, referring to FIG. 12, the cap plate (10) according to one embodiment of the present invention has a smaller change in the outer diameter of the cap plate (10) compared to the comparative example, so it has the effect of minimizing the phenomenon of gas being discharged through the cap plate (10) and the clamping part (214) when a thermal event occurs in the battery cell (20).

[0143] FIG. 13 is a schematic diagram showing the configuration of a battery pack including a battery cell according to each embodiment of the present invention.

[0144] Referring to FIG. 13, a battery pack (30) according to one embodiment of the present invention may include one or more battery cells (20) according to each embodiment of the present invention as described above. Here, the battery cell (20) according to each embodiment of the present invention includes a cap plate (10) according to each embodiment of the present invention.

[0145] Additionally, the battery pack (30) may further include a pack case (31) for housing a battery cell (20), and various devices for controlling the charging and discharging of the battery cell (20), such as a BMS, a current sensor, a fuse, etc.

[0146] FIG. 14 is a drawing for explaining a vehicle including the battery pack of FIG. 13.

[0147] Referring to FIG. 14, a vehicle (40) according to one embodiment of the present invention may include one or more battery cells (20) or battery packs (30) according to each of the above embodiments. Here, the vehicle (40) includes various vehicles configured to use electricity, such as, for example, electric vehicles or hybrid vehicles.

[0148] In this specification, where terms indicating directions such as up, down, left, and right are used, these terms are used merely for convenience of explanation, and it is obvious to those skilled in the art that they may vary depending on the location of the object or the position of the observer.

[0149] Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims set forth below by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed above should be considered in an illustrative rather than a restrictive sense. That is, the scope of the true technical spirit of the present invention is indicated in the claims, and all variations within the equivalent scope thereof should be interpreted as being included in the present invention.

[0150] The present invention relates to a cap plate, a battery cell, a battery pack including the same, and an automobile, and is particularly applicable to industries related to secondary batteries.

Claims

1. As a cap plate coupled to a battery can, A main body that seals the above battery can; A vent notch formed in the main body and rupturing when the pressure inside the battery can exceeds a critical value; and A cap plate comprising a fracture guide formed in the main body portion, spaced apart from the above-mentioned vent notch portion and configured to allow the vent notch portion to be fractured at a preset position.

2. In Paragraph 1, At least one rigidity-enhancing portion is formed in the above main body, and A cap plate characterized by having a fracture-inducing section formed between a plurality of rigidity-increasing sections.

3. In Paragraph 2, A cap plate characterized in that the above-mentioned rigidity-enhancing portion is composed of an indentation groove formed in an intaglio shape on the main body portion inside the above-mentioned vent notch portion.

4. In Paragraph 3, Three of the above-mentioned grooves are formed, and A cap plate characterized by having one fracture-inducing portion formed between two of the three insertion grooves.

5. In Paragraph 4, The above-mentioned fracture-inducing parts are formed in three numbers, and A cap plate characterized by having a central portion formed in a straight line connecting to the fracture guide portion at the portion where the three fracture guide portions meet.

6. In Paragraph 5, A cap plate characterized in that each of the three above-mentioned fracture-inducing parts is spaced 120 degrees apart from each other.

7. In Paragraph 3, The above insertion groove is, A first part formed on the inner side of the above-mentioned vent notch; A second part extending from one side of the first part toward the inside of the main body part; A third part extending from the other side of the first part toward the inside of the main body part; and A cap plate characterized by including a fourth part connecting the second part and the third part.

8. In Paragraph 7, The above-mentioned vent notch includes a curve, A cap plate characterized in that the first part above has a curve parallel to a part of the curve of the vent notch portion.

9. In Paragraph 7, A cap plate characterized in that the second part and the third part are formed in a straight shape.

10. In Paragraph 9, A cap plate characterized in that the virtual extension line of the second part and the virtual extension line of the third part are formed to meet each other.

11. In Paragraph 7, A cap plate characterized in that the above-mentioned fourth part has a curve parallel to a part of the curve of the above-mentioned first part.

12. An electrode assembly comprising an anode plate, a cathode plate, and a separator interposed between the anode plate and the cathode plate; A battery can having an opening and a closing portion, in which the above electrode assembly is housed; and A battery cell characterized by including a cap plate according to claims 1 to 10 configured to seal the opening of the battery can.

13. In Paragraph 12, It includes a sealing gasket interposed between the edge of the cap plate and the opening of the battery can, and The above battery can is, A beading portion formed such that the outer circumference of the battery can is pressed inward; and A battery cell characterized by including a clamping portion that extends and bends inwardly into the battery can and wraps around and secures the edge of the cap plate together with the sealing gasket.

14. A battery pack comprising at least one battery cell according to paragraph 12.

15. An automobile comprising at least one battery cell according to paragraph 12.

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