Battery cell, battery pack and vehicle comprising battery pack

Abstract

A battery cell according to an embodiment of the present invention comprises: an electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; a battery case that accommodates the electrode assembly through an opening portion formed at one side of the battery case; and a case cover covering the opening portion and having an exhaust portion configured to break when an internal pressure in the battery case increases to a predetermined level or higher, wherein the exhaust part comprises an upper notch part arranged on the upper surface of the shell cover and a lower notch part arranged on the lower surface of the shell cover; and the upper notch part and the lower notch part are arranged to be offset from each other.

Description

Technical Field

[0001] The present disclosure relates to battery cells, battery packs, and vehicles including the same.

[0002] This application claims priority to Korean Patent Application No. 10-2022-0157708 filed in Korea on November 22, 2022, the disclosure of which is incorporated herein by reference. Background Art

[0003] Secondary batteries are easily applicable depending on the product group and have electrical characteristics such as high energy density, and are generally used in electric vehicles (EV) or hybrid electric vehicles (HEV) driven by electric drive sources and portable devices. These secondary batteries have attracted attention as new energy sources that improve eco-friendliness and energy efficiency because they have the main advantages of being able to significantly reduce the use of fossil fuels and not generating byproducts due to energy use.

[0004] Currently widely used secondary battery packs include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. The operating voltage of a unit secondary battery cell (i.e., a unit battery cell) is about 2.5V to 4.5V. Therefore, when the output voltage is higher than the required voltage, the battery pack can be configured by connecting a plurality of battery cells in series. In addition, according to the required charge / discharge capacity of the battery pack, the battery pack can be configured by connecting a plurality of battery cells in parallel. Therefore, the number of battery cells included in the battery pack can be set in various ways according to the required output voltage or charge / discharge capacity.

[0005] Meanwhile, the battery cell may include a battery can and a cover covering one surface of the battery can. In this case, the cover may have a vent portion formed to prevent an increase in internal pressure caused by gas generated inside the battery case. However, in order to ensure a certain level of vent pressure in conventional battery cells, a large number of processes are required to form the notch, thereby increasing damage to the mold. Therefore, it is necessary to reduce damage to the mold and improve the life when forming the notch. In addition, when manufacturing the notch portion, there is a problem of productivity degradation due to a large amount of forming. Summary of the invention

[0006] Technical issues

[0007] The present disclosure has been designed to solve the related art problems, and thus the present disclosure aims to effectively ensure venting pressure when forming a notch in a vent portion of a battery cell even if the notch forming amount is small.

[0008] Furthermore, the present disclosure is directed to reducing damage to a mold when forming a recess in a vent portion of a battery cell, thereby increasing and improving the life of the battery cell.

[0009] According to another aspect, the present disclosure is directed to improving productivity by reducing the amount of notch formation.

[0010] However, the technical problems to be solved by the present invention are not limited to the above problems, and those skilled in the art will clearly understand other problems not mentioned above from the description of the present invention described below.

[0011] Technical Solution

[0012] According to one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly, the electrode assembly comprising a first electrode, a second electrode and a separator interposed between the first electrode and the second electrode; a battery case, the battery case being configured to receive the electrode assembly through an opening formed on one side thereof; and a case cover, the case cover being configured to cover the opening and having a vent portion, the vent portion being configured to rupture when the internal pressure of the battery case increases to a predetermined level or higher, wherein the vent portion comprises an upper notch portion arranged on the upper surface of the case cover and a lower notch portion arranged on the lower surface of the case cover, and wherein the upper notch portion and the lower notch portion are arranged in a staggered state.

[0013] Preferably, the exhaust portion may be configured to form a circular closed loop.

[0014] In one aspect of the present disclosure, a center line of the upper notch portion and a center line of the lower notch portion may be spaced apart from each other by a predetermined distance in a radial direction.

[0015] Preferably, the upper notch portion may be disposed more inwardly than the lower notch portion in a radial direction.

[0016] In another aspect of the present disclosure, the upper notch portion and the lower notch portion may be configured such that widths thereof decrease as the upper notch portion and the lower notch portion approach the interior of the case cover from the surface of the case cover.

[0017] In another aspect of the present disclosure, the upper notch portion may have an axisymmetric structure having an inclination relative to a center line of the upper notch portion, and the lower notch portion may have an axisymmetric structure having an inclination relative to a center line of the lower notch portion.

[0018] In one aspect of the present disclosure, a first straight line and a second straight line can be defined in a longitudinal section passing through the center of the shell cover, wherein the first straight line is a virtual straight line passing through the shortest distance between the upper notch portion and the lower notch portion, and the second straight line is a virtual straight line perpendicular to the first straight line.

[0019] In this case, an angle formed between the second straight line and the surface of the housing cover may be greater than 0 degrees and less than 90 degrees.

[0020] In one aspect of the present disclosure, assuming that the entrance width of the upper notch portion is W1 and the entrance width of the lower notch portion is W2, the distance between the center line of the upper notch portion and the center line of the lower notch portion satisfies the following formula (1):

[0021]

[0022] In another aspect of the present disclosure, the upper notch portion and the lower notch portion may be configured to be point-symmetrical to each other in a longitudinal cross-section passing through a center of the housing cover.

[0023] In another aspect of the present disclosure, in a longitudinal cross-section passing through the center of the housing cover, the shortest distance between the upper notch portion and the lower notch portion can be configured to be greater than the shortest distance between the upper notch portion and the lower notch portion when the upper notch portion and the lower notch portion are arranged at the same position in the radial direction.

[0024] In another aspect of the present disclosure, in a longitudinal cross-section passing through the center of the housing cover, a shortest distance between the upper notch portion and the lower notch portion may be smaller than a thickness of the housing cover.

[0025] In another aspect of the present disclosure, a region forming the upper notch portion and a region forming the lower notch portion may at least partially overlap each other in a direction perpendicular to the housing cover.

[0026] In another aspect of the present disclosure, the shortest distance between the upper notch portion and the lower notch portion may be greater than 10% of the thickness of the housing cover.

[0027] Meanwhile, the present disclosure provides a battery pack including at least one battery cell according to the above-mentioned embodiment.

[0028] In addition, the present disclosure also provides a vehicle, which includes at least one battery pack described in the above embodiment.

[0029] Beneficial Effects

[0030] According to the processor disclosure, even if the notch forming amount is small, a predetermined level of exhaust pressure in the battery cell can be ensured.

[0031] According to another aspect of the present disclosure, a smaller notch formation amount makes it possible to reduce damage to the mold, thereby desirably increasing the life of the battery cell.

[0032] According to another aspect of the present disclosure, productivity can be improved by reducing the amount of notch formation.

[0033] However, effects obtainable from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned above will be clearly understood by those skilled in the art from the description of the present invention described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the detailed description of the present invention, are used to provide further understanding of the technical concept of the present disclosure; therefore, the present disclosure is not to be construed as being limited to the accompanying drawings.

[0035] Figure 1 is a diagram showing a battery cell according to an embodiment of the present disclosure.

[0036] Figure 2 yes Figure 1 A longitudinal sectional view of the .

[0037] Figure 3 yes Figure 1 Longitudinal cross-section of a battery cell.

[0038] Figure 4 is a diagram showing a housing cover according to an embodiment of the present disclosure.

[0039] Figure 5 2 is a diagram showing a housing cover corresponding to a comparative example of the present disclosure.

[0040] Figure 6 is a diagram showing a housing cover according to an embodiment of the present disclosure.

[0041] Figure 7 is a diagram illustrating a housing cover according to another embodiment of the present disclosure.

[0042] Figure 8 is a diagram illustrating an exhaust portion according to an embodiment of the present disclosure.

[0043] Fig. 9 1 is a diagram showing a rupture process of a vent portion corresponding to a comparative example in the present disclosure.

[0044] Fig.10 is a diagram illustrating a rupture process of a vent according to an embodiment of the present disclosure.

[0045] Fig.11 is a diagram showing a battery pack including a battery cell according to an embodiment of the present disclosure.

[0046] Fig.12 It is shown that Fig.11 Diagram of a battery pack in a vehicle. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but are interpreted based on the principle that the inventor is allowed to appropriately define the terms for the best interpretation, based on the meanings and concepts corresponding to the technical aspects of the present disclosure. Therefore, the configurations proposed in the embodiments of this specification and the accompanying drawings only indicate the most preferred embodiments of the present disclosure, and do not represent all the technical ideas of the present disclosure, so it should be understood that various equivalents and modifications may be made to them when submitting this application.

[0048] In addition, to help understand the present disclosure, the drawings are not drawn to scale and the sizes of some elements may be exaggerated. In addition, the same reference numerals may indicate the same elements between different embodiments.

[0049] Stating that two objects being compared are identical means that they are "substantially identical." Thus, "substantially identical" can include situations with a deviation that is considered low in the art, for example, less than 5%. In addition, a parameter that is consistent in a certain area can indicate consistency from an average viewing angle.

[0050] Although "first", "second", etc. are used to describe various elements, these elements are not limited to these terms. These terms are only used to distinguish one element from another element, and unless otherwise specified, the first element may also be the second element.

[0051] Throughout the specification, unless otherwise specified, a corresponding element may include a single element or a plurality of elements.

[0052] A configuration in which an element is disposed “above or below” or “on top or bottom” of a target element may indicate that the element may be disposed in contact with an upper or lower surface of the target element, and another element may be interposed between the target element and an element disposed on top or bottom of the target element.

[0053] In addition, the expression “an element is connected, coupled or fastened to another element” should be understood that the elements can be directly connected or fastened to each other, another element can be “interposed” between the elements, or the elements can be “connected”, “coupled” or “fastened” through other elements.

[0054] Throughout the specification, unless otherwise specified, “A and / or B” may mean A or B or A and B, and “C to D” may mean “equal to or greater than C and equal to or less than D” unless otherwise specified.

[0055] For ease of explanation, in this specification, the longitudinal direction of the winding axis of the electrode assembly 10 wound into a winding core shape will be referred to as the "axial direction (Y)". In addition, the direction around the winding axis will be referred to as the "circumferential direction (X)". In addition, the direction moving closer to or away from the winding axis will be referred to as the "radial direction". Among them, the direction close to the winding axis is referred to as the "centripetal direction", and the direction away from the winding axis is referred to as the "centrifugal direction".

[0056] Figure 1 is a diagram showing a battery cell 1 according to an embodiment of the present disclosure, Figure 2 yes Figure 1 A longitudinal sectional view of the . Figure 3 yes Figure 1 A longitudinal cross-sectional view of a battery cell 1 in FIG.

[0057] Reference Figure 1 , a battery cell 1 according to an embodiment of the present disclosure includes an electrode assembly 10, a battery case 20, and a case cover 30. The battery cell 1 may further include a current collector 40. The present disclosure is not limited to a specific type of battery and may be applied to other types of batteries, such as prismatic batteries.

[0058] Reference Figure 2 and Figure 3 , the electrode assembly 10 includes a first electrode connector 11 and a second electrode connector 12. Specifically, the electrode assembly 10 includes a first electrode, a second electrode and a separator interposed therebetween. The electrode assembly 10 has a structure in which the first electrode and the second electrode are wound around a winding axis with a separator sandwiched therebetween, thereby defining a core and a peripheral surface. That is, the electrode assembly 10 applied to the present disclosure may be a core-wound electrode assembly 10. In this case, an additional separator may be provided on the peripheral surface of the electrode assembly 10 to insulate it from the battery case 20. The electrode assembly 10 may have a winding structure known in the art without limitation.

[0059] Meanwhile, in the present disclosure, any active material known in the art may be used, but is not limited to being a positive electrode active material coated on a positive electrode plate and a negative electrode active material coated on a negative electrode plate.

[0060] refer to Figure 1 and Figure 2 The battery case 20 is a substantially cylindrical container having an opening formed on one side thereof, and is made of a conductive metal material. Typically, the side surface of the battery case 20 and the bottom surface opposite to the opening are formed integrally. That is, the battery case 20 is typically configured so that its top in the height direction is open and the bottom is closed. The bottom surface of the battery case 20 may be configured in a substantially flat shape. The battery case 20 receives the electrode assembly 10 through an opening formed on one side in the height direction. The battery case 20 may also receive an electrolyte through the opening.

[0061] The battery case 20 may have a curling portion 21 formed at an end portion adjacent to an opening provided at the top of the battery case 20. The battery case 20 may also include a crimping portion 22 formed on the curling portion 21. The curling portion 21 may be configured so that the outer peripheral surface of the battery case 20 is press-fitted to a predetermined depth. More specifically, the curling portion 21 may be configured to be press-fitted inwardly in a region between an opening formed on one side of the battery case 20 and a receiving portion that receives the electrode assembly 10.

[0062] The beading portion 21 is formed above the electrode assembly 10. The inner diameter of the battery case 20 in the region where the beading portion 21 is formed is smaller than the diameter of the electrode assembly 10.

[0063] The curling portion 21 provides a support surface for placing the case cover 30. In addition, the curling portion 21 can provide a support surface for placing and connecting at least a portion of the edge of the current collector 40. That is, at least a portion of the edge of the current collector 40 of the present disclosure and / or the edge of the case cover 30 can be placed on the upper surface of the curling portion 21. In order to stably support at least a portion of the edge of the current collector 40 and / or the edge of the case cover 30, the upper surface of the curling portion 21 can be configured to extend in a direction substantially parallel to the bottom surface of the battery case 20, that is, in a direction substantially perpendicular to the side wall of the battery case 20.

[0064] The beading portion 21 can prevent the electrode assembly 10 (which may have a size approximately corresponding to the inner diameter of the battery case 20) from coming out through the opening formed at the top of the battery case 20 and serve as a support portion on which the case cover 30 is placed. The upper beading portion 21 can serve as a support portion for fixing the current collector 40, the sealing gasket G1, etc., and the case cover 30.

[0065] The crimping portion 22 is formed on the top of the beading portion 21. The crimping portion 22 is configured to extend and bend to surround the edge of the housing cover 30 disposed above the beading portion 21. Such a configuration of the crimping portion 22 can fix the housing cover 30 to the beading portion 21.

[0066] Reference Figures 1 to 3 , the housing cover 30 may include a vent 31 formed to prevent an increase in internal pressure due to gas generated inside the battery housing 20. The vent 31 may be configured to rupture when the internal pressure of the battery housing 20 increases to a predetermined level or higher. For example, the vent 31 may be formed in a portion of the housing cover 30, and may be a region that is structurally more fragile than the surrounding area so that it is easily ruptured when internal pressure is applied thereto. For example, the vent 31 may be a region having a thickness less than that of the surrounding area.

[0067] That is, for some reason, a thermal event may occur inside the battery cell 1 to generate exhaust gas, and the pressure inside the battery case 20 may increase due to the exhaust gas. At this time, the vent portion 31 corresponding to the area that is structurally weaker than the surrounding area so as to be easily ruptured when the internal pressure of the battery cell 1 increases may rupture when the exhaust gas is generated.

[0068] Reference Figures 1 to 3 , the shell cover 30 covers the opening formed on one side of the battery shell 20. The shell cover 30 may be fixed by a crimping portion 22 formed at the top of the battery shell 20. In this case, a sealing gasket G1 may be inserted between the battery shell 20 and the shell cover 30 and between the current collector 40 and the shell cover 30 to improve the fixing force and airtightness of the battery shell 20. In this case, the contact portion 33a and / or the second contact portion may be inserted between the crimping portion 21 of the battery shell 20 and the sealing gasket G1. As described above, the contact portion 33a and / or the second contact portion inserted between the crimping portion 21 and the sealing gasket G1 may be fixed by bending the crimping portion 22 extending upward from the crimping portion 21.

[0069] Meanwhile, in the present disclosure, the case cover 30 is not necessarily a component used as a current path. Therefore, as long as the airtightness of the opening of the battery case 20 can be ensured by firmly fixing the battery case 20 and the case cover 30 by welding or using other components, the sealing gasket G1 does not need to be applied.

[0070] Figure 4 is a diagram showing a housing cover 30 according to an embodiment of the present disclosure. Figure 5 2 is a diagram showing a housing cover 30 corresponding to a comparative example of the present disclosure. Figure 6 is a diagram showing a housing cover 30 according to an embodiment of the present disclosure.

[0071] Reference Figure 4 and Figure 6 , the exhaust portion 31 may include an upper notch portion N1 provided on an upper surface of the housing cover 30 and a lower notch portion N2 provided on a lower surface of the housing cover 30. Here, the upper notch portion N1 and the lower notch portion N2 may be provided in a staggered state.

[0072] According to this structure, since the upper notch portion N1 and the lower notch portion N2 are disposed in a staggered state, the shear stress may be a principal stress applied to the region between the upper notch portion N1 and the lower notch portion N2.

[0073] If the upper notch portion N1 and the lower notch portion N2 are Figure 5 In the conventional housing cover 30 shown in FIG. 1 , the tensile stress may be the main stress applied to the area between the upper notch portion N1 and the lower notch portion N2. The area between the upper notch portion N1 and the lower notch portion N2 is subjected to the same stress as Figure 5 or Figure 6 In the case of the same pressure as shown, it is more likely to rupture when shear stress is applied than when tensile stress is applied. Therefore, according to the present disclosure, even if a lower exhaust pressure is applied to the exhaust portion 31, the exhaust portion 31 may rupture. Alternatively, since the upper notch portion N1 and the lower notch portion N2 are in a staggered state, the same exhaust pressure can be ensured even when the notch forming amount is small. As a result, damage to the mold can be reduced by reducing the forming amount, and it is expected that the life of the housing cover 30 can be increased.

[0074] refer to Figures 1 to 4 , the vent portion 31 may be configured to form a substantially circular closed loop. Therefore, if exhaust gas is discharged from the interior of the battery cell 1 so that internal pressure is applied to the case cover 30 in an upward direction, the vent portion 31 may be ruptured, and the inner area of ​​the circular closed loop of the case cover 30 may be ruptured. Therefore, exhaust gas can be easily performed.

[0075] Figure 7 is a diagram showing a housing cover 30 according to another embodiment of the present disclosure.

[0076] In one aspect of the present disclosure, the center line of the upper notch portion N1 and the center line of the lower notch portion N2 may be configured to be spaced apart from each other by a predetermined distance in the radial direction. Here, the center line may refer to a line extending in the height direction of the battery cell 1 and passing through the width direction center of the notch portion N1 or N2.

[0077] For example, refer to Figure 6 , the upper notch portion N1 may be arranged inwardly more than the lower notch portion N2 in the radial direction. As another embodiment of the present disclosure, refer to Figure 7 , the upper notch portion N1 may be disposed further outward in the radial direction than the lower notch portion N2.

[0078] According to the structure configured so that the center line of the upper notch portion N1 and the center line of the lower notch portion N2 are spaced apart from each other by a predetermined distance in the radial direction, the shear stress may be the principal stress applied to the area between the upper notch portion N1 and the lower notch portion N2. Therefore, according to the present disclosure, even if a lower exhaust pressure is applied to the exhaust portion 31, the exhaust portion 31 may be broken. Alternatively, since the upper notch portion N1 and the lower notch portion N2 are in a staggered state, the same exhaust pressure can be ensured even when the notch forming amount is small. As a result, damage to the mold can be reduced by reducing the forming amount, and it is expected that the life of the housing cover 30 can be increased.

[0079] In another aspect of the present disclosure, the upper notch portion N1 and the lower notch portion N2 may be configured such that the widths thereof decrease as they approach the inside of the case cover 30 from the surface thereof.

[0080] For example, refer to Figure 6 or Figure 7 , the upper notch portion N1 and the lower notch portion N2 may be configured to have a substantially V-shaped cross section. Alternatively, in another embodiment, the upper notch portion N1 and the lower notch portion N2 may be configured to have a substantially U-shaped cross section. That is, the cross sections of the notch portions N1 and N2 may be configured to have slopes on both sides.

[0081] According to this structure, when the center lines of the upper notch portion N1 and the lower notch portion N2 are spaced a predetermined distance apart from each other in the radial direction, shear stress may be a principal stress applied to a region between the upper notch portion N1 and the lower notch portion N2.

[0082] If the notch portions N1 and N2 have a rectangular cross section, unlike the present disclosure, even if the center line of the upper notch portion N1 and the center line of the lower notch portion N2 are spaced apart from each other by a predetermined distance in the radial direction, the area between the upper notch portion N1 and the lower notch portion N2 may have a vertical structure, not an inclined structure. Therefore, in this state, shear stress cannot be the principal stress applied to the area between the upper notch portion N1 and the lower notch portion N2. Therefore, the exhaust pressure required for rupture may increase compared to the present disclosure.

[0083] On the other hand, according to the present disclosure, since the area between the upper notch portion N1 and the lower notch portion N2 has an inclined structure, when the center line of the upper notch portion N1 and the center line of the lower notch portion N2 are radially spaced a predetermined distance apart, the stress applied to the area between the upper notch portion N1 and the lower notch portion N2 may be a shear stress.

[0084] Preferably, refer to Figure 6 or Figure 7 , the upper notch portion N1 may have an axisymmetric structure having an inclination with respect to the center line of the upper notch portion N1. On the other hand, the lower notch portion N2 may have an axisymmetric structure having an inclination with respect to the center line of the lower notch portion N2.

[0085] According to this structure, since the area between the upper notch portion N1 and the lower notch portion N2 has an inclined structure, the shear stress can be the principal stress applied to the area between the upper notch portion N1 and the lower notch portion N2 when the center line of the upper notch portion N1 and the center line of the lower notch portion N2 are spaced apart by a predetermined distance in the radial direction. In addition, since the notch portions N1 and N2 have an axisymmetric structure with respect to the center line, the notch portions N1 and N2 can be easily formed during the manufacturing process.

[0086] Figure 8 is a diagram showing the exhaust portion 31 according to an embodiment of the present disclosure.

[0087] Reference Figure 8In a longitudinal section passing through the center of the housing cover 30, a first straight line SL and a second straight line PL can be defined, the first straight line SL being a virtual straight line passing through the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2, and the second straight line PL being a virtual straight line perpendicular to the first straight line SL.

[0088] In this case, according to one aspect of the present disclosure, an angle formed between the second straight line PL and the surface of the housing cover 30 may be greater than 0 degree and less than 90 degrees.

[0089] For example, Figure 5 As shown, if the upper notch portion N1 and the lower notch portion N2 are arranged on the same line, the first straight line SL can be perpendicular to the housing cover 30. Accordingly, since the second straight line PL is parallel to the housing cover 30, the angle formed between the second straight line PL and the surface of the housing cover 30 can be 0 degrees. According to this structure, the stress applied to the area between the upper notch portion N1 and the lower notch portion N2 becomes a tensile stress, so that the exhaust pressure required for the rupture of the exhaust portion 31 can be increased. Although in order to reduce the exhaust pressure, the thickness of the area between the upper notch portion N1 and the lower notch portion N2 can be reduced by increasing the size of the notch portion, this requires a larger amount of forming, thereby increasing the possibility of damaging the mold. Accordingly, the life of the housing cover 30 may be reduced. Therefore, preferably, the angle formed between the second straight line PL and the surface of the housing cover 30 is greater than 0 degrees.

[0090] On the other hand, if the distance D2 between the center line of the upper notch portion N1 and the center line of the lower notch portion N2 is too long, the first straight line SL may be almost parallel to the surface of the housing cover 30. Therefore, the angle formed between the second straight line PL and the surface of the housing cover 30 may be close to 90 degrees. In this case, the distance D2 between the upper notch portion N1 and the lower notch portion N2 is excessively increased to increase the thickness of the area between the upper notch portion N1 and the lower notch portion N2, thereby further increasing the exhaust pressure required for the exhaust portion 31 to rupture. Therefore, preferably, the angle formed between the second straight line PL and the surface of the housing cover 30 is less than 90 degrees.

[0091] Furthermore, it is more preferred that the angle formed between the second straight line PL and the surface of the housing cover 30 is within a range of 30 to 60 degrees. If the angle falls within a range of 30 to 60 degrees, the thickness of the region between the upper notch portion N1 and the lower notch portion N2 can be maintained at an appropriate level, and at the same time, shear stress can be applied to the region between the upper notch portion N1 and the lower notch portion N2. Therefore, according to the present embodiment, even with a smaller notch forming amount, the same exhaust pressure can be ensured. As a result, damage to the mold can be reduced by reducing the forming amount, and it is expected that the life of the housing cover 30 can be increased.

[0092] In another aspect of the present disclosure, referring to Figure 8 Preferably, the distance D2 between the center line of the upper notch portion N1 and the center line of the lower notch portion N2 satisfies the following formula:

[0093]

[0094] Here, W1 represents the width of the entrance of the upper notch portion N1, and W2 represents the width of the entrance of the lower notch portion N2. That is, preferably, the distance D2 between the center line of the upper notch portion N1 and the center line of the lower notch portion N2 is smaller than the average value of the width W1 of the entrance of the upper notch portion N1 and the width W2 of the entrance of the lower notch portion N2, and is greater than 0.

[0095] If the distance D2 between the center line of the upper notch portion N1 and the center line of the lower notch portion N2 is greater than the average value of the width W1 of the entrance of the upper notch portion N1 and the width W2 of the entrance of the lower notch portion N2, the distance D2 between the upper notch portion N1 and the lower notch portion N2 may be excessively increased, thereby increasing the thickness of the area between the upper notch portion N1 and the lower notch portion N2, and thus the exhaust pressure required for the exhaust portion 31 to rupture may be further increased. On the other hand, if the distance D2 between the center line of the upper notch portion N1 and the center line of the lower notch portion N2 is 0, the upper notch portion N1 and the lower notch portion N2 may be located on the same line. Therefore, the main force applied to the exhaust portion 31 may be tensile stress. As a result, the exhaust pressure required for the exhaust portion 31 to rupture may be further increased. Therefore, only when the above formula (1) is satisfied, the same exhaust pressure can be ensured even if the notch forming amount is small. As a result, damage to the mold can be reduced by reducing the forming amount, and the life of the housing cover 30 is expected to be increased.

[0096] In another aspect of the present disclosure, the upper notch portion N1 and the lower notch portion N2 may be configured to be point-symmetrical to each other in a longitudinal cross-section passing through the center of the housing cover 30 .

[0097] Reference Figure 8 , based on the intersection of the first straight line SL and the second straight line PL, the upper notch portion N1 and the lower notch portion N2 can be configured to be point symmetrical to each other on a longitudinal cross section passing through the center of the housing cover 30. That is, the shape of the upper notch portion N1 and the shape of the lower notch portion N2 can be configured to be substantially the same. According to this structure, since the notch portions N1 and N2 have an inclined shape, shear stress can be applied to the area between the upper notch portion N1 and the lower notch portion N2.

[0098] In another aspect of the present disclosure, on a longitudinal cross-section passing through the center of the housing cover 30, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 can be configured to be greater than the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 when the upper notch portion N1 and the lower notch portion N2 are arranged at the same position in the radial direction.

[0099] In such Figure 5 In the case where the upper notch portion N1 and the lower notch portion N2 are arranged on the same line, tensile stress may be applied to the area between the upper notch portion N1 and the lower notch portion N2, thereby possibly increasing the exhaust pressure required for the exhaust portion 31 to rupture. Therefore, in this case, in order to reduce the exhaust pressure, the thickness of the area between the upper notch portion N1 and the lower notch portion N2 must be reduced by increasing the size of the notch portion. That is, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 on the longitudinal section passing through the center of the housing cover 30 must be reduced. However, in this case, the forming amount may increase, thereby increasing the possibility of damage to the mold. Accordingly, the life of the housing cover 30 may be reduced.

[0100] On the other hand, according to Figure 8 The structure in which the upper notch portion N1 and the lower notch portion N2 are arranged in a staggered state as shown can mainly apply shear stress to the area between the upper notch portion N1 and the lower notch portion N2. Under the same pressure, the exhaust portion is more likely to rupture when shear stress is applied than when tensile stress is applied, so the same exhaust pressure can be ensured with a smaller notch forming amount. That is, even if the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 in the longitudinal section passing through the center of the housing cover 30 is shorter than that in the longitudinal section passing through the center of the housing cover 30, the exhaust portion D1 can be ruptured. Figure 5 The distance in the case of the middle is increased more, and the same exhaust pressure can also be ensured. As a result, the damage to the mold can be reduced by reducing the forming amount, and the life of the housing cover 30 is expected to be increased.

[0101] In another aspect of the present disclosure, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 in a longitudinal cross-section passing through the center of the case cover 30 may be configured to be smaller than the thickness of the case cover 30 .

[0102] For example, refer to Figure 8 , the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 may be less than the thickness of the housing cover 30. In addition, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 may be less than the maximum width of the notch portions N1 and N2.

[0103] If the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 is configured to be too large, the thickness of the area between the upper notch portion N1 and the lower notch portion N2 may increase, so that the exhaust pressure required for the vent portion 31 to rupture may further increase. Therefore, as described above, preferably, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 is configured to be lower than or equal to a certain level.

[0104] In another aspect of the present disclosure, the region where the upper notch portion N1 is formed and the region where the lower notch portion N2 is formed may be configured to at least partially overlap each other in a direction perpendicular to the housing cover 30. For example, referring to Figure 6 and Figure 7 , the area where the upper notch portion N1 is formed and the area where the lower notch portion N2 is formed can be configured to at least partially overlap each other in a direction substantially perpendicular to the housing cover 30, that is, in the up-down direction in the figure. According to this structure, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 can be configured within a predetermined range. If the area where the upper notch portion N1 is formed and the area where the lower notch portion N2 is formed do not overlap each other along a direction substantially perpendicular to the housing cover 30, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 may be excessively increased. In this case, the thickness of the area between the upper notch portion N1 and the lower notch portion N2 can be increased, thereby further increasing the exhaust pressure required for the exhaust portion 31 to rupture. Therefore, as described above, preferably, the area where the upper notch portion N1 is formed and the area where the lower notch portion N2 is formed are configured to at least partially overlap each other in a direction substantially perpendicular to the housing cover 30.

[0105] In another aspect of the present disclosure, preferably, the shortest distance between the upper notch portion N1 and the lower notch portion N2 is greater than 10% of the thickness of the housing cover 30 .

[0106] For example, according to an embodiment of the present disclosure, the exhaust pressure of a battery cell 1 of a specific design including a case cover 30 made of SUS430 and having a thickness of 0.7t may need to reach approximately 17kgf / cm 2 In order to obtain the above-mentioned exhaust pressure, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 must be about 0.070 mm, which corresponds to about 10% of the thickness of the housing cover 30. As described above, if the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 is less than or equal to the above-mentioned level, the mold is likely to be damaged during forming, thereby reducing the life of the housing cover 30. Therefore, preferably, the shortest distance D1 between the upper notch portion N1 and the lower notch portion N2 is greater than 10% of the thickness of the housing cover 30.

[0107] Fig. 9 is a diagram showing a rupture process of the vent portion 31 corresponding to a comparative example in the present disclosure, and Fig.10 is a diagram illustrating a rupture process of the vent portion 31 according to an embodiment of the present disclosure.

[0108] Reference Fig. 9In the conventional housing cover 30, the upper notch portion N1 and the lower notch portion N2 may be arranged on the same line. In this case, stress is applied to the area between the upper notch portion N1 and the lower notch portion N2 in the direction of arrow A. In this case, tensile stress may be mainly applied in the direction of arrow A.

[0109] On the other hand, refer to Fig.10 In the housing cover 30 according to the embodiment of the present disclosure, since the upper notch portion N1 and the lower notch portion N2 are arranged in a staggered state, stress is applied to the area between the upper notch portion N1 and the lower notch portion N2 in the direction of arrow B. In this case, shear stress can be mainly applied in the direction of arrow B. Under the same magnitude of pressure, the exhaust portion is more likely to rupture when shear stress is applied than when tensile stress is applied. Therefore, according to the present disclosure, even if a lower exhaust pressure is applied to the exhaust portion 31, the exhaust portion 31 may rupture. Alternatively, as in the present disclosure, if the upper notch portion N1 and the lower notch portion N2 are in a staggered state, the same exhaust pressure can be ensured even when the notch forming amount is small. As a result, damage to the mold can be reduced by reducing the forming amount, and the life of the housing cover 30 is expected to be increased.

[0110] Reference Figure 1 and Figure 2 The current collector 40 according to an embodiment of the present disclosure is accommodated inside the battery case 20, is electrically connected to the electrode assembly 10, and is also electrically connected to the battery case 20. That is, the current collector 40 electrically connects the electrode assembly 10 and the battery case 20.

[0111] Reference Fig.11 , the battery pack 3 according to the embodiment of the present disclosure includes a battery assembly and a battery pack housing 2 for accommodating the battery assembly, in which a plurality of battery cells 1 according to the above-mentioned embodiment of the present disclosure are electrically connected. For ease of explanation, components such as bus bars, cooling units, and power terminals for electrical connection are omitted in the drawings of the present disclosure. That is, the battery pack 3 may also include elements of the battery pack 3 known at the time of filing the present disclosure, such as a BMS, a battery pack housing, a relay, a current sensor, and the like.

[0112] Reference Fig.12The vehicle 5 according to the embodiment of the present disclosure may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes the battery pack 3 according to the embodiment of the present disclosure. The vehicle 5 includes a four-wheel vehicle and a two-wheel vehicle. According to the embodiment of the present disclosure, the vehicle 5 operates by receiving power from the battery pack 3. In addition to the battery pack 3, the vehicle 5 according to the present disclosure may further include various other elements included in the vehicle 5. For example, in addition to the battery pack 3 according to the present disclosure, the vehicle 5 according to the present disclosure may further include a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like.

[0113] Meanwhile, although terms indicating directions such as upward and downward are used in the present specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the position of a target object or the position of an observer.

[0114] As described above, although the present disclosure has been described with reference to limited embodiments and drawings, the present disclosure is not limited thereto, and various modifications and changes are possible within the technical concept of the present disclosure and the equivalent scope of the claims to be described below by those skilled in the art to which the present disclosure belongs.

[0115] [Explanation of Reference Numerals]

[0116] 5: Vehicles

[0117] 3: Battery Pack

[0118] 2: Battery pack housing

[0119] 1: Battery Cell

[0120] 10: Electrode assembly

[0121] 20: Battery housing

[0122] 21: Curling part

[0123] 22: Crimping part

[0124] 30: Shell cover

[0125] 31: Exhaust

[0126] N1: Upper notch part

[0127] N2: Lower notch

[0128] G1: Sealing gasket

Claims

1. A battery cell, comprising: an electrode assembly, the electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; a battery case configured to receive the electrode assembly through an opening formed at one side thereof; as well as a case cover configured to cover the opening and having a vent portion configured to rupture when an internal pressure of the battery case increases to a predetermined level or higher, wherein the exhaust portion comprises an upper notch portion disposed on the upper surface of the housing cover and a lower notch portion disposed on the lower surface of the housing cover, and Wherein, the upper notch portion and the lower notch portion are arranged in a staggered state.

2. The battery cell according to claim 1, in, The exhaust portion forms a circular closed loop.

3. The battery cell according to claim 1, in, A center line of the upper notch portion and a center line of the lower notch portion are spaced apart from each other by a predetermined distance in a radial direction.

4. The battery cell according to claim 1, in, The upper notch portion is disposed further inwardly than the lower notch portion in a radial direction.

5. The battery cell according to claim 1, in, The upper notch portion and the lower notch portion are configured such that widths thereof decrease as the upper notch portion and the lower notch portion approach the interior of the housing cover from the surface of the housing cover.

6. The battery cell according to claim 1, in, The upper notch portion has an axisymmetric structure having an inclination relative to a center line of the upper notch portion, and wherein the lower notch portion has an axisymmetric structure having an inclination relative to a center line of the lower notch portion.

7. The battery cell according to claim 1, in, A first straight line and a second straight line are defined in a longitudinal section passing through the center of the housing cover, the first straight line being a virtual straight line passing through the shortest distance between the upper notch portion and the lower notch portion, the second straight line being a virtual straight line perpendicular to the first straight line, and an angle formed between the second straight line and the surface of the housing cover being greater than 0 degrees and less than 90 degrees.

8. The battery cell according to claim 1, in, Assuming that the entrance width of the upper notch is W1 and the entrance width of the lower notch is W2, the distance between the center line of the upper notch and the center line of the lower notch satisfies the following formula (1):

9. The battery cell according to claim 1, in, The upper notch portion and the lower notch portion are configured to be point-symmetrical to each other in a longitudinal cross section passing through the center of the housing cover.

10. The battery cell according to claim 1, in, In a longitudinal section passing through the center of the housing cover, a shortest distance between the upper notch portion and the lower notch portion is greater than a shortest distance between the upper notch portion and the lower notch portion when the upper notch portion and the lower notch portion are arranged at the same position in the radial direction.

11. The battery cell according to claim 1, in, In a longitudinal section passing through the center of the housing cover, a shortest distance between the upper notch portion and the lower notch portion is smaller than a thickness of the housing cover.

12. The battery cell according to claim 1, in, The region forming the upper notch portion and the region forming the lower notch portion at least partially overlap each other in a direction perpendicular to the housing cover.

13. The battery cell according to claim 1, in, The shortest distance between the upper notch portion and the lower notch portion is greater than 10% of the thickness of the housing cover.

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

15. A vehicle comprising at least one battery pack according to claim 14.

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