Battery cell, battery pack, and vehicle comprising the same

Abstract

A battery cell according to an embodiment of the present application includes: an electrode assembly including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; a battery case accommodating 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 a gas discharge portion configured to be ruptured when an internal pressure in the battery case increases to a predetermined level or more, wherein: the gas discharge portion includes an upper notch portion provided at an upper surface of the case cover and a lower notch portion provided at a lower surface of the case cover; and the upper notch portion and the lower notch portion are disposed to be offset from each other.

Description

Battery cells, battery packs and vehicles including the battery pack

[0001] This application claims priority to Korean Patent Application 10-2022-0157708, filed in Korea on November 22, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to battery cells, battery packs, and vehicles including them. Background Technology

[0003] Secondary batteries, due to their ease of application and electrical characteristics such as high energy density, are commonly used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric drive sources, as well as portable devices. These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency because they offer the key advantages of significantly reducing fossil fuel use and producing no byproducts due to energy consumption.

[0004] Currently widely used secondary battery packs include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of a single secondary battery cell (i.e., a single battery cell) is approximately 2.5V to 4.5V. Therefore, when the output voltage is higher than the required voltage, multiple battery cells can be connected in series to configure a battery pack. Furthermore, depending on the required charge / discharge capacity of the battery pack, multiple battery cells can be connected in parallel to configure the battery pack. Therefore, the number of battery cells included in a battery pack can be set in various ways according to the required output voltage or charge / discharge capacity.

[0005] Simultaneously, the battery cell may include a battery can and a cover covering one side of the battery can. In this case, the cover may have a venting section formed to prevent an increase in internal pressure caused by gas generated inside the battery casing. However, to ensure a certain level of venting pressure in a conventional battery cell, a large number of processes are required to form the notch, thereby increasing damage to the mold. Therefore, it is necessary to reduce mold damage and improve mold life when forming the notch. Furthermore, when manufacturing the notch, there is a problem of reduced productivity due to the large number of forming processes. Summary of the Invention

[0006] Technical issues

[0007] This disclosure has been designed to solve related technical problems, and therefore aims to effectively ensure venting pressure even when the notch is formed in the venting section of a battery cell, even if the notch forming amount is small.

[0008] Furthermore, this disclosure aims to reduce damage to the mold when forming notches in the venting section of the battery cell, thereby increasing and improving the lifespan of the battery cell.

[0009] On the other hand, this disclosure aims to improve productivity by reducing the amount of notch forming.

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

[0011] Technical solution

[0012] According to one aspect of this disclosure, a battery cell is provided, the battery cell comprising: an electrode assembly including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a battery housing configured to receive the electrode assembly through an opening formed on one side thereof; and a housing cover configured to cover the opening and having a vent, the vent being configured to rupture when the internal pressure of the battery housing increases to a predetermined level or higher, wherein the vent includes an upper recess on an upper surface of the housing cover and a lower recess on a lower surface of the housing cover, and wherein the upper recess and the lower recess are disposed in a staggered manner.

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

[0014] In one aspect of this disclosure, the centerline of the upper recess and the centerline of the lower recess may be spaced apart from each other by a predetermined distance in the radial direction.

[0015] Preferably, the upper recess may be positioned further inward in the radial direction than the lower recess.

[0016] In another aspect of this disclosure, the upper recess and the lower recess may be configured such that their width decreases as the upper recess and the lower recess move from the surface of the housing cover toward the interior of the housing cover.

[0017] In another aspect of this disclosure, the upper recess may have an axisymmetric structure with an inclination relative to the center line of the upper recess, and the lower recess may have an axisymmetric structure with an inclination relative to the center line of the lower recess.

[0018] In one aspect of this disclosure, a first straight line and a second straight line may be 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 recess and the lower recess, and the second straight line being a virtual straight line perpendicular to the first straight line.

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

[0020] In one aspect of this disclosure, assuming the inlet width of the upper recess is W1 and the inlet width of the lower recess is W2, the distance between the centerline of the upper recess and the centerline of the lower recess satisfies the following formula (1):

[0021]

[0022] In another aspect of this disclosure, the upper recess and the lower recess may be configured to be point-symmetric to each other in a longitudinal section passing through the center of the housing cover.

[0023] In another aspect of this disclosure, in a longitudinal section passing through the center of the housing cover, the shortest distance between the upper recess and the lower recess can be configured to be greater than the shortest distance between the upper recess and the lower recess when they are located at the same position in the radial direction.

[0024] In another aspect of this disclosure, in a longitudinal section passing through the center of the housing cover, the shortest distance between the upper recess and the lower recess may be less than the thickness of the housing cover.

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

[0026] In another aspect of this disclosure, the shortest distance between the upper recess and the lower recess can be greater than 10% of the thickness of the housing cover.

[0027] Meanwhile, this disclosure provides a battery pack that includes at least one battery cell according to the above embodiments.

[0028] In addition, this disclosure also provides a vehicle that includes at least one battery pack as described in the above embodiments.

[0029] Beneficial effects

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

[0031] According to another aspect of this disclosure, a smaller notch forming amount reduces damage to the mold, thereby potentially increasing the lifespan of the battery cell.

[0032] According to another aspect of this disclosure, productivity can be increased by reducing the amount of notch forming.

[0033] However, the effects available from this disclosure are not limited to those described above, and those skilled in the art will clearly understand, based on the description of the invention below, other effects not mentioned above. Attached Figure Description

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

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

[0036] Figure 2 is a longitudinal sectional perspective view of Figure 1.

[0037] Figure 3 is a longitudinal cross-sectional view of the battery cell in Figure 1.

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

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

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

[0043] Figure 9 is a diagram showing the rupture process of the exhaust section corresponding to the comparative example in this disclosure.

[0044] Figure 10 is a diagram illustrating the rupture process of the exhaust section according to an embodiment of the present disclosure.

[0045] Figure 11 is a diagram illustrating a battery pack including battery cells according to an embodiment of the present disclosure.

[0046] Figure 12 is a diagram showing a vehicle including the battery pack shown in Figure 11. Detailed Implementation

[0047] The preferred embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but rather is interpreted based on the principle that inventors are allowed to appropriately define terms for best interpretation, and on the meanings and concepts corresponding to the technical aspects of this disclosure. Therefore, the configurations presented in the embodiments and drawings of this specification indicate only the most preferred embodiments of this disclosure and do not represent all the technical ideas of this disclosure. Thus, it should be understood that various equivalents and modifications can be made thereto upon filing this application.

[0048] Additionally, to aid in understanding this disclosure, the drawings are not drawn to scale, and the dimensions of some elements may be exaggerated. Furthermore, the same reference numerals may indicate the same elements across different embodiments.

[0049] Describing two objects as identical means that they are "substantially identical." Therefore, "substantially identical" can include cases with deviations considered low in the field, such as less than 5%. Furthermore, consistent parameters within a certain region can indicate consistency from an average perspective.

[0050] Although terms such as "first" and "second" 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, and unless otherwise stated, the first element may also be the second element.

[0051] Throughout this specification, unless otherwise stated, the corresponding elements may include one or more elements.

[0052] The configuration of an element being positioned "above or below" or "top or bottom" on a target element indicates that the element can be configured to contact the upper or lower surface of the target element, and another element can be inserted between the target element and the element positioned at the top or bottom of the target element.

[0053] In addition, the phrase "components are connected, coupled or fastened to another component" should be understood to mean that components can be directly connected or fastened to each other, and another component can be "inserted" between components, or components can be "connected", "coupled" or "fastened" through other components.

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

[0055] For ease of explanation, in this specification, the longitudinal direction of the winding axis of the electrode assembly 10 wound into a core shape will be referred to as the "axial direction (Y)". Furthermore, the direction around the winding axis will be referred to as the "circumferential direction (X)". Additionally, the direction of movement towards or away from the winding axis will be referred to as the "radial direction". The direction closer to the winding axis is called the "centripetal direction", and the direction farther from the winding axis is called the "centrifugal direction".

[0056] Figure 1 is a diagram showing a battery cell 1 according to an embodiment of the present disclosure, Figure 2 is a longitudinal sectional perspective view of Figure 1, and Figure 3 is a longitudinal sectional view of the battery cell 1 in Figure 1.

[0057] Referring to FIG1, a battery cell 1 according to an embodiment of the present disclosure includes an electrode assembly 10, a battery casing 20, and a casing cover 30. The battery cell 1 may also include a current collector 40. This disclosure is not limited to a specific type of battery and can be applied to other types of batteries, such as prismatic batteries.

[0058] Referring to Figures 2 and 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 inserted therebetween. The electrode assembly 10 has a structure in which the first electrode and the second electrode, sandwiching the separator, are wound around a winding axis, thereby defining a core and an outer peripheral surface. That is, the electrode assembly 10 used in this disclosure can be a core-type electrode assembly 10. In this case, an additional separator can be provided on the outer peripheral surface of the electrode assembly 10 to insulate it from the battery casing 20. The electrode assembly 10 can have a winding structure known in the art without limitation.

[0059] Furthermore, any active material known in the art can be used in this disclosure, but is not limited to, as a positive active material coated on a positive electrode plate and a negative active material coated on a negative electrode plate.

[0060] Referring to Figures 1 and 2, the battery casing 20 is a generally cylindrical container with an opening formed on one side thereon, and is made of a conductive metallic material. Typically, the side surface and the bottom surface opposite the opening of the battery casing 20 are integrally formed. That is, the battery casing 20 is generally configured such that it is open at the top and closed at the bottom in the height direction. The bottom surface of the battery casing 20 may be configured to be a generally flat shape. The battery casing 20 receives the electrode assembly 10 through the opening formed on one side in the height direction. The battery casing 20 may also receive the electrolyte through the opening.

[0061] The battery housing 20 may have a rolled edge 21 formed at the end of an opening located adjacent to the top of the battery housing 20. The battery housing 20 may also include a press-fit portion 22 formed on the rolled edge 21. The rolled edge 21 may be configured to press-fit the outer peripheral surface of the battery housing 20 to a predetermined depth. More specifically, the rolled edge 21 may be configured to press-fit inwardly in the region between the opening formed on one side of the battery housing 20 and the receiving portion that accommodates the electrode assembly 10.

[0062] A rolled edge 21 is formed above the electrode assembly 10. The inner diameter of the battery housing 20 in the region where the rolled edge 21 is formed is smaller than the diameter of the electrode assembly 10.

[0063] The crimped portion 21 provides a support surface for mounting the housing cover 30. Additionally, the crimped portion 21 can provide a support surface for mounting 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 and / or the edge of the housing cover 30 can be mounted on the upper surface of the crimped portion 21. To stably support at least a portion of the edge of the current collector 40 and / or the edge of the housing cover 30, the upper surface of the crimped portion 21 can be configured to extend in a direction substantially parallel to the bottom surface of the battery housing 20, i.e., in a direction substantially perpendicular to the sidewalls of the battery housing 20.

[0064] The rolled edge 21 prevents the electrode assembly 10 (which may have a size approximately corresponding to the inner diameter of the battery housing 20) from protruding through the opening formed at the top of the battery housing 20 and serves as a support for the housing cover 30. The upper rolled edge 21 can also serve as a support for fixing the current collector 40, the sealing gasket G1, and the housing cover 30.

[0065] A crimping portion 22 is formed on the top of the rolled edge portion 21. The crimping portion 22 is configured to extend and bend to surround the edge of the housing cover 30 disposed above the rolled edge portion 21. This configuration of the crimping portion 22 secures the housing cover 30 to the rolled edge portion 21.

[0066] Referring to Figures 1 to 3, the housing cover 30 may include a vent 31, which is 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 structurally more fragile area than the surrounding area so that it is easily ruptured when internal pressure is applied. For example, the vent 31 may be a region with a thickness less than the surrounding area.

[0067] In other words, for some reason, a thermal event may occur inside the battery cell 1 to generate venting, and the pressure inside the battery casing 20 may increase due to the venting. At this time, the venting section 31, which is structurally more fragile than the surrounding area so that it is prone to rupture when the internal pressure of the battery cell 1 increases, may rupture when venting occurs.

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

[0069] Furthermore, in this disclosure, the housing cover 30 is not necessarily a component that serves as a current path. Therefore, as long as the airtightness of the opening of the battery housing 20 can be ensured by welding or using other components to securely fix the battery housing 20 and the housing cover 30, the sealing gasket G1 is not required.

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

[0071] Referring to Figures 4 and 6, the venting section 31 may include an upper recess N1 provided on the upper surface of the housing cover 30 and a lower recess N2 provided on the lower surface of the housing cover 30. Here, the upper recess N1 and the lower recess N2 may be provided in a staggered manner.

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

[0073] If the upper notch N1 and the lower notch N2 are positioned on the same line in the conventional housing cover 30 shown in FIG. 5, tensile stress may be the principal stress applied to the region between the upper notch N1 and the lower notch N2. When the region between the upper notch N1 and the lower notch N2 is subjected to the same magnitude of pressure as shown in FIG. 5 or FIG. 6, it is more likely to crack when shear stress is applied compared to when tensile stress is applied. Therefore, according to this disclosure, even if a lower venting pressure is applied to the venting section 31, the venting section 31 may crack. Alternatively, since the upper notch N1 and the lower notch N2 are staggered, the same venting pressure can be ensured even with a smaller notch forming amount. As a result, damage to the mold can be reduced by decreasing the forming amount, and the life of the housing cover 30 is expected to increase.

[0074] Referring to Figures 1 to 4, the venting section 31 can be configured to form a substantially circular closed loop. Therefore, if venting occurs from the inside of the battery cell 1, causing internal pressure to be applied to the housing cover 30 in the upward direction, the venting section 31 may rupture, and the inner region of the circular closed loop of the housing cover 30 may rupture. Thus, venting 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 this disclosure, the center line of the upper recess N1 and the center line of the lower recess N2 can be configured to be spaced apart from each other by a predetermined distance in the radial direction. Here, the center line can refer to a line extending along the height direction of the battery cell 1 and passing through the center of the width direction of the recess N1 or N2.

[0077] For example, referring to FIG6, the upper recess N1 may be positioned further inward than the lower recess N2 in the radial direction. As another embodiment of this disclosure, referring to FIG7, the upper recess N1 may be positioned further outward than the lower recess N2 in the radial direction.

[0078] According to the configuration in which the center lines of the upper notch N1 and the lower notch N2 are spaced apart from each other by a predetermined distance in the radial direction, the shear stress can be the principal stress applied to the region between the upper notch N1 and the lower notch N2. Therefore, according to this disclosure, even if a low venting pressure is applied to the venting section 31, the venting section 31 may still rupture. Alternatively, since the upper notch N1 and the lower notch N2 are staggered, the same venting 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.

[0079] In another aspect of this disclosure, the upper recess N1 and the lower recess N2 can be configured such that their width decreases as they move closer to the interior of the housing cover 30 from their surface.

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

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

[0082] If the notches N1 and N2 have rectangular cross-sections, unlike this disclosure, even if the centerlines of the upper notch N1 and the lower notch N2 are radially spaced apart by a predetermined distance, the region between the upper notch N1 and the lower notch N2 can have a vertical structure instead of an inclined structure. Therefore, in this state, shear stress cannot be the principal stress applied to the region between the upper notch N1 and the lower notch N2. Consequently, the venting pressure required for rupture may increase compared to this disclosure.

[0083] On the other hand, according to this disclosure, since the region between the upper recess N1 and the lower recess N2 has an inclined structure, the stress applied to the region between the upper recess N1 and the lower recess N2 can be shear stress when the center line of the upper recess N1 and the center line of the lower recess N2 are radially spaced by a predetermined distance.

[0084] Preferably, referring to FIG6 or FIG7, the upper notch N1 may have an axisymmetric structure with an inclination relative to the center line of the upper notch N1. On the other hand, the lower notch N2 may have an axisymmetric structure with an inclination relative to the center line of the lower notch N2.

[0085] According to this structure, since the region between the upper notch N1 and the lower notch N2 has an inclined structure, when the center lines of the upper notch N1 and the lower notch N2 are radially spaced by a predetermined distance, the shear stress can be the principal stress applied to the region between the upper notch N1 and the lower notch N2. Furthermore, since the notches N1 and N2 have an axisymmetric structure with respect to the center lines, the notches N1 and N2 can be easily formed during the manufacturing process.

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

[0087] Referring to Figure 8, in 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 is a virtual straight line passing through the shortest distance D1 between the upper recess N1 and the lower recess N2, and the second straight line PL is a virtual straight line perpendicular to the first straight line SL.

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

[0089] For example, as shown in Figure 5, if the upper notch N1 and the lower notch N2 are arranged on the same line, the first straight line SL can be perpendicular to the housing cover 30. Correspondingly, 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 region between the upper notch N1 and the lower notch N2 becomes tensile stress, thereby increasing the venting pressure required for the venting section 31 to rupture. Although the thickness of the region between the upper notch N1 and the lower notch N2 can be reduced by increasing the size of the notch to decrease the venting pressure, this requires a larger molding process, thus increasing the possibility of mold damage. Consequently, the lifespan 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 recess N1 and the center line of the lower recess 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 can be close to 90 degrees. In this case, the excessive increase in the distance D2 between the upper recess N1 and the lower recess N2 increases the thickness of the area between the upper recess N1 and the lower recess N2, thereby further increasing the exhaust pressure required for the exhaust section 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, more preferably, the angle formed between the second straight line PL and the surface of the housing cover 30 is in the range of 30 to 60 degrees. If the angle falls within the range of 30 to 60 degrees, the thickness of the region between the upper notch N1 and the lower notch 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 N1 and the lower notch N2. Therefore, according to this embodiment, the same venting pressure can be ensured even with a smaller notch forming amount. 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.

[0092] In another aspect of this disclosure, referring to FIG8, preferably, the distance D2 between the center line of the upper notch N1 and the center line of the lower notch N2 satisfies the following formula:

[0093]

[0094] Here, W1 represents the width of the entrance to the upper recess N1, and W2 represents the width of the entrance to the lower recess N2. That is, preferably, the distance D2 between the center line of the upper recess N1 and the center line of the lower recess N2 is less than the average of the widths W1 and W2 of the entrances to the upper recess N1 and the lower recess N2, and is greater than 0.

[0095] If the distance D2 between the centerline of the upper notch N1 and the centerline of the lower notch N2 is greater than the average of the width W1 of the inlet of the upper notch N1 and the width W2 of the inlet of the lower notch N2, the distance D2 between the upper notch N1 and the lower notch N2 may be excessively increased, thereby increasing the thickness of the area between the upper notch N1 and the lower notch N2, and thus may further increase the venting pressure required for the vent 31 to rupture. On the other hand, if the distance D2 between the centerline of the upper notch N1 and the centerline of the lower notch N2 is 0, the upper notch N1 and the lower notch N2 may be located on the same line. Therefore, the main force applied to the vent 31 may be tensile stress. As a result, the venting pressure required for the vent 31 to rupture may be further increased. Therefore, only when the above formula (1) is satisfied can the same venting pressure required for the vent 31 to rupture 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 this disclosure, the upper recess N1 and the lower recess N2 can be configured to be point-symmetric to each other in a longitudinal section passing through the center of the housing cover 30.

[0097] Referring to Figure 8, based on the intersection of the first straight line SL and the second straight line PL, the upper notch N1 and the lower notch N2 can be configured to be point-symmetric to each other on a longitudinal section passing through the center of the housing cover 30. That is, the shapes of the upper notch N1 and the lower notch N2 can be configured to be substantially the same. According to this structure, since the notches N1 and N2 have inclined shapes, shear stress can be applied to the region between the upper notch N1 and the lower notch N2.

[0098] In another aspect of this disclosure, in a longitudinal section passing through the center of the housing cover 30, the shortest distance D1 between the upper recess N1 and the lower recess N2 can be configured to be greater than the shortest distance D1 between the upper recess N1 and the lower recess N2 when they are radially positioned at the same location.

[0099] When the upper notch N1 and lower notch N2 are positioned on the same line as shown in Figure 5, tensile stress may be applied to the area between them, potentially increasing the venting pressure required for the vent 31 to rupture. Therefore, in this case, to reduce the venting pressure, the thickness of the area between the upper notch N1 and lower notch N2 must be reduced by increasing the size of the notches. That is, the shortest distance D1 between the upper notch N1 and lower notch N2 in 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 likelihood of mold damage. Consequently, the lifespan of the housing cover 30 may be reduced.

[0100] On the other hand, according to the structure shown in Figure 8 where the upper notch N1 and the lower notch N2 are arranged in a staggered state, shear stress can be mainly applied to the area between the upper notch N1 and the lower notch N2. Under the same pressure, the vent is more likely to rupture when shear stress is applied compared to when tensile stress is applied. Therefore, the same venting pressure required for the vent 31 to rupture can be ensured with a smaller notch forming amount. That is, even if the shortest distance D1 between the upper notch N1 and the lower notch N2 on the longitudinal section passing through the center of the housing cover 30 is increased more than the distance in the case of Figure 5, the same venting pressure required for the vent 31 to rupture can be ensured. 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.

[0101] In another aspect of this disclosure, the shortest distance D1 between the upper recess N1 and the lower recess N2 in a longitudinal section passing through the center of the housing cover 30 can be configured to be less than the thickness of the housing cover 30.

[0102] For example, referring to Figure 8, the shortest distance D1 between the upper recess N1 and the lower recess N2 can be less than the thickness of the housing cover 30. Furthermore, the shortest distance D1 between the upper recess N1 and the lower recess N2 can be less than the maximum width of the recesses N1 and N2.

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

[0104] In another aspect of this disclosure, the region forming the upper notch N1 and the region forming the lower notch N2 can be configured to at least partially overlap each other in a direction perpendicular to the housing cover 30. For example, referring to Figures 6 and 7, the region forming the upper notch N1 and the region forming the lower notch N2 can be configured to at least partially overlap each other in a direction substantially perpendicular to the housing cover 30, i.e., in the up-down direction shown in the figures. According to this configuration, the shortest distance D1 between the upper notch N1 and the lower notch N2 can be configured within a predetermined range. If the region forming the upper notch N1 and the region forming the lower notch N2 do not overlap each other in a direction substantially perpendicular to the housing cover 30, the shortest distance D1 between the upper notch N1 and the lower notch N2 may be excessively increased. In this case, the thickness of the region between the upper notch N1 and the lower notch N2 can be increased, thereby further increasing the exhaust pressure required for the venting section 31 to rupture. Therefore, as described above, preferably, the region having the upper recess N1 and the region having the lower recess N2 are configured to at least partially overlap each other in a direction substantially perpendicular to the housing cover 30.

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

[0106] For example, according to embodiments of this disclosure, the venting pressure of a battery cell 1, including a housing cover 30 made of SUS430 and having a thickness of 0.7t, may need to reach approximately 17 kgf / cm². 2 To achieve the aforementioned exhaust pressure, the shortest distance D1 between the upper notch N1 and the lower notch N2 must be approximately 0.070 mm, which corresponds to approximately 10% of the thickness of the housing cover 30. As mentioned above, if the shortest distance D1 between the upper notch N1 and the lower notch N2 is less than or equal to the aforementioned level, the mold is likely to be damaged during formation, thereby reducing the lifespan of the housing cover 30. Therefore, preferably, the shortest distance D1 between the upper notch N1 and the lower notch N2 is greater than 10% of the thickness of the housing cover 30.

[0107] Figure 9 is a diagram showing the rupture process of the exhaust section 31 corresponding to the comparative example in this disclosure, and Figure 10 is a diagram showing the rupture process of the exhaust section 31 according to an embodiment of this disclosure.

[0108] Referring to Figure 9, in a conventional housing cover 30, the upper recess N1 and the lower recess N2 can be arranged on the same line. In this case, stress is applied in the direction of arrow A to the area between the upper recess N1 and the lower recess N2. In this case, tensile stress can be mainly applied in the direction of arrow A.

[0109] On the other hand, referring to FIG10, in the housing cover 30 according to the embodiment of the present disclosure, since the upper notch N1 and the lower notch N2 are arranged in a staggered state, stress is applied to the region between the upper notch N1 and the lower notch 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 pressure, the vent is more likely to rupture when shear stress is applied compared to when tensile stress is applied. Therefore, according to the present disclosure, even if a lower venting pressure is applied to the vent 31, the vent 31 may rupture. Alternatively, as in the present disclosure, if the upper notch N1 and the lower notch N2 are staggered, the same venting pressure required for the vent 31 to rupture 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] Referring to Figures 1 and 2, the current collector 40 according to an embodiment of the present disclosure is housed inside the battery housing 20, electrically connected to the electrode assembly 10, and also electrically connected to the battery housing 20. That is, the current collector 40 is electrically connected to the electrode assembly 10 and the battery housing 20.

[0111] Referring to FIG11, the battery pack 3 according to an embodiment of the present disclosure includes a battery assembly and a battery pack housing 2 for housing the battery assembly. In the battery assembly, a plurality of battery cells 1 according to the above-described embodiment of the present disclosure are electrically connected. For ease of explanation, components such as busbars, cooling units, and power terminals for electrical connections are omitted from the accompanying drawings of this disclosure. That is, the battery pack 3 may also include elements of the battery pack 3 known at the time of submission of this disclosure, such as a BMS, a battery pack housing, a relay, a current sensor, etc.

[0112] Referring to FIG12, the vehicle 5 according to an embodiment of the present disclosure may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack 3 according to an embodiment of the present disclosure. The vehicle 5 includes four-wheeled vehicles and two-wheeled vehicles. According to an 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 also include various other components 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 also include a body, a motor, control devices such as an electronic control unit (ECU), etc.

[0113] At the same time, although terms indicating directions such as up and down are used in this specification, it will be apparent to those skilled in the art that these terms are for ease of interpretation only and may vary depending on the position of the target object or the observer's position.

[0114] As described above, although this disclosure has been described with reference to limited embodiments and drawings, this disclosure is not limited thereto, and various modifications and variations are possible within the scope of the technical concept of this disclosure and the equivalents of the claims to which those skilled in the art to which this disclosure pertains.

[0115] [Explanation of reference numerals in the attached figures]

[0116] 5: Vehicles

[0117] 3: Battery pack

[0118] 2: Battery pack casing

[0119] 1: Battery cells

[0120] 10: Electrode assembly

[0121] 20: Battery casing

[0122] 21: Rolled edge

[0123] 22: Crimping section

[0124] 30: Housing cover

[0125] 31: Exhaust section

[0126] N1: Upper notch part

[0127] N2: Lower recess

[0128] G1: Sealing gasket

Claims

1. A battery cell, the battery cell comprising: An electrode assembly, the electrode assembly including a first electrode, a second electrode, and a diaphragm inserted between the first electrode and the second electrode; A battery housing configured to receive the electrode assembly through an opening formed on one side thereon; and a housing cover configured to cover the opening and having a vent, the vent being configured to rupture when the internal pressure of the battery housing increases to a predetermined level or higher, wherein the vent includes an upper recess formed by the upper surface of the housing cover recessing into the material of the housing cover and a lower recess formed by the lower surface of the housing cover recessing into the material of the housing cover, and wherein the upper recess and the lower recess are arranged in a staggered manner.

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

3. The battery cell according to claim 1, wherein, The centerline of the upper recess and the centerline of the lower recess are spaced apart from each other by a predetermined distance in the radial direction.

4. The battery cell according to claim 1, wherein, The upper recess is positioned further inward in the radial direction than the lower recess.

5. The battery cell according to claim 1, wherein, The upper recess and the lower recess are configured such that their width decreases as they move from the surface of the housing cover closer to the interior of the housing cover.

6. The battery cell according to claim 1, wherein, The upper recess has an axisymmetric structure with an inclination relative to the center line of the upper recess, and the lower recess has an axisymmetric structure with an inclination relative to the center line of the lower recess.

7. The battery cell according to claim 1, wherein, 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 is a virtual straight line that passes through the shortest distance between the upper recess and the lower recess. The second straight line is a virtual straight line that is perpendicular to the first straight line. The angle formed between the second straight line and the surface of the housing cover is greater than 0 degrees and less than 90 degrees.

8. The battery cell according to claim 1, wherein, Assuming the inlet width of the upper recess is W1 and the inlet width of the lower recess is W2, the distance D2 between the centerline of the upper recess and the centerline of the lower recess satisfies the following formula (1): ...Official (1).

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

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

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

12. The battery cell according to claim 1, wherein, The regions forming the upper recess and the regions forming the lower recess overlap at least partially with each other in a direction perpendicular to the housing cover.

13. The battery cell according to claim 1, wherein, The shortest distance between the upper recess and the lower recess 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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