Battery pack

Abstract

The present invention relates to a battery pack containing a cell assembly, the battery pack being characterized by comprising: a battery pack case in which the cell assembly is disposed; and an upper case coupled to the pack case so as to cover an upper portion of the cell assembly disposed inside the pack case, in which the upper case includes, at a lower end thereof, a protrusion for pressing the upper portion of the cell assembly disposed in the pack case.

Description

Technical Field

[0001] The present disclosure relates to a battery pack accommodating a battery cell assembly.

[0002] This application claims the benefit of priority of Korean Patent Application No. 10-2023-0107092, filed on Aug. 16, 2023, the disclosure of which is incorporated herein by reference. Background Art

[0003] Generally, a battery cell includes: an electrode assembly in which alternating layers of an electrode and a separator are stacked; an electrode lead wire connected to the electrode of the electrode assembly; a case from which the electrode lead wire is led out to the outside, and the case surrounds the electrode assembly; and an electrolyte filled inside the case together with the electrode assembly.

[0004] According to the shape of the case, the battery cells can be roughly classified into cylindrical battery cells, pouch-type battery cells, and prismatic battery cells.

[0005] Although battery cells are sometimes used alone, they are more commonly configured as a plurality of battery cells electrically connected in series and / or in parallel to each other. In particular, a plurality of battery cells are electrically connected to each other to form a battery cell stack. In addition, the battery cell stack can be stored in a module frame to form a single battery cell assembly.

[0006] Figure 1 A battery cell assembly 20 accommodating a pouch-type battery cell 24 is illustrated, and Figure 2 A battery cell assembly 20 accommodating a prismatic battery cell 24 is illustrated.

[0007] As Figure 1 shown, the pouch-type battery cell 24 is arranged such that the electrode lead wire 26 of each battery cell 24 is located on the side. Accordingly, the battery cell assembly 20 can have terminals formed on the side corresponding to the electrode lead wire 26 of the accommodated battery cell 24.

[0008] The battery cell assembly 20 accommodating the pouch-type battery cell 24 can have end plates 21 connected to the front and rear surfaces of the battery cell stack 25 to protect the terminals. Accordingly, the battery cell assembly 20 accommodating the pouch-type battery cell 24 can have external terminals electrically connected to the battery cell stack 25 on the end plates 21.

[0009] As Figure 2 shown, the prismatic battery cell 24 is arranged such that the electrode lead wire 26 of each battery cell 24 faces upward. Accordingly, the battery cell assembly 20 can have terminals formed on the upper part corresponding to the electrode lead wire 26 of the accommodated battery cell 24. Accordingly, the battery cell assembly 20 accommodating the prismatic battery cell 24 can be disposed on the module frame 22 when the external terminals electrically connected to the battery stack 25 are located on the upper part of the battery stack 25.

[0010] As Figure 2 shown, the cell assembly 20 accommodating the prismatic cell 24 does not adopt the configuration of the end plate 21 increased due to the electrode lead 26 provided on the side portion.

[0011] As Figure 1 and Figure 2 shown, the cell assemblies 20 are slightly different based on the shape of the cells 24 accommodated therein, but are the same in other aspects that the internal cell stack 25 is surrounded and protected by the module frame 22.

[0012] The cell assemblies 20 used in products requiring high power (e.g., electric vehicles) may be two or more that are electrically connected in series and / or in parallel with each other to form a higher-level device (e.g., a battery pack).

[0013] Figure 3 Illustrated are a conventional battery pack and the cell assembly 20 accommodated therein. The battery pack may include a battery pack case 10 and an upper case. The cell assembly 20 is directly inserted and accommodated in the battery pack case 10, and the upper case is coupled to the battery pack case 10 such that the space inside the battery pack case 10 is sealed from the outside. As Figure 3 shown, each of the cell assemblies 20 is stored in a partitioned space inside the battery pack case 10.

[0014] In addition, in the cell assembly 20 including a plurality of cells 24 tightly packaged together in a small space, some of the cells 24 may experience problems such as short circuits, which causes the temperature of the cells 24 to continuously increase, resulting in a thermal runaway phenomenon where the temperature of the cells 24 exceeds the threshold temperature. High-temperature gas and spark particles can be ejected from the thermally runaway cells 24 (the spark particles refer to, for example, active materials deintercalated from the electrodes inside the cells 24 or molten aluminum particles). Additionally, in some cases, some of the cells 24 may even burst into flames.

[0015] As described above, if gas is generated inside the cell assembly 20 surrounded by the module frame 22, the end plate 21, etc., there may be a risk that the cell assembly 20 may explode due to the gas pressure, and the explosion may cause the transfer of flames, heat, etc. to other cell assemblies. The conventional cell assembly 20 may be formed with an opening hole 23 through which the gas can be discharged to solve the above explosion problem.

[0016] Figure 4 Illustrated is a conventional cell assembly 20 having an opening hole 23. The cell assembly 20 having the opening hole 23 can prevent the generation of internal pressure by quickly discharging the high-temperature gas even if the internal cell 24 generates high-temperature gas due to thermal runaway.

[0017] However, when the opening hole 23 is formed in the battery cell assembly 20 as described above, there is often a problem that the spark particles and flames generated in the battery cell 24 are transmitted to other battery cell assemblies 20 through the opening hole 23. Summary of the Invention

[0018] Technical Problem

[0019] Therefore, the present disclosure aims to solve the above problems and provides a battery pack having a structure capable of effectively discharging internally generated gas to the outside in the case of thermal runaway.

[0020] Another object of the present disclosure is to provide a battery pack having a structure capable of delaying the progress of thermal runaway to other battery cell assemblies even if thermal runaway occurs in any one of the battery cell assemblies accommodated therein.

[0021] Other objects and advantages of the present disclosure will be understood from the following description and will become more apparent from the embodiments of the present disclosure. It will also be apparent that the objects and advantages of the present disclosure can be achieved by the means and combinations disclosed in the claims.

[0022] Technical Solution

[0023] The present disclosure provides a battery pack accommodating a battery cell assembly.

[0024] The battery pack includes: a battery pack housing in which the battery cell assembly is disposed; and an upper housing coupled to the battery pack housing to cover an upper portion of the battery cell assembly disposed inside the battery pack housing, wherein the upper housing includes a protrusion at a lower end, and the protrusion presses an upper portion of the battery cell assembly disposed in the battery pack housing.

[0025] The battery cell assembly may include: a battery cell stack including a plurality of battery cells; and a module frame surrounding at least one side of the battery cell stack.

[0026] According to the battery pack of claim 2, the module frame may include an opening hole that is opened to expose the battery cell stack in the module frame to the outside.

[0027] The opening hole may be formed in any one of a circular shape and a polygonal shape.

[0028] The opening hole may extend along at least one of a longitudinal direction and a width direction of the battery cell assembly.

[0029] The battery cell assembly may further include a protective sheet attached to a surface of the module frame to cover the opening hole.

[0030] The protrusion of the upper housing may be formed at a position where the opening hole of the battery cell assembly is not provided.

[0031] An opening hole may be formed in the module frame located on the upper part of the battery cell assembly.

[0032] The protective sheet may be a porous structure including a plurality of holes that selectively allow gas to pass through.

[0033] The protective sheet may be a structure in which no holes are formed to prevent gas from passing through.

[0034] The protective sheet may have electrical insulation properties.

[0035] The protective sheet may have heat resistance and flame retardancy.

[0036] The protrusion may be in the form of a column with a flat end.

[0037] The protrusion may be in the form of a downwardly protruding projection.

[0038] The protrusion may extend along at least one of the longitudinal direction and the width direction of the upper housing.

[0039] Advantageous Effects

[0040] According to the present disclosure, in a battery pack accommodating a plurality of battery cell assemblies, even if thermal runaway occurs in one of the battery cell assemblies, heat transfer to other adjacent battery cell assemblies can be maximally suppressed to improve explosion-proof safety. Brief Description of the Drawings

[0041] Figure 1 A conventional battery cell assembly including a pouch-type battery cell is illustrated.

[0042] Figure 2 A conventional battery cell assembly including a prismatic battery cell is illustrated.

[0043] Figure 3 A conventional battery pack and the battery cell assemblies accommodated therein are illustrated.

[0044] Figure 4 A conventional battery cell assembly is illustrated.

[0045] Figure 5 A battery pack according to a first embodiment of the present disclosure is illustrated.

[0046] Figure 6 The battery cell assembly of the present disclosure is illustrated.

[0047] Figure 7 It is illustrated that the protective sheet is removed from the Figure 6 battery cell assembly.

[0048] Figure 8 It is a bottom perspective view of the upper housing.

[0049] Figure 9 The upper housing is illustrated with hidden lines to show the protrusion from the Figure 5 battery pack in

[0050] Figure 10 is illustrated Figure 9 the state where the upper housing and the battery pack housing are coupled together.

[0051] Figure 11 is a simplified cross-sectional view of the battery pack that houses one of the cell assemblies.

[0052] Figure 12 is illustrated the migration of gas in the battery pack during thermal runaway in the cell stack Figure 11 in

[0053] Figure 13 is illustrated a battery pack according to a second embodiment of the present disclosure.

[0054] Figure 14 is illustrated Figure 13 the housed cell assembly in

[0055] Figure 15 is illustrated the protective sheet being removed from the Figure 14 cell assembly in

[0056] Figure 16 is illustrated a battery pack according to a third embodiment of the present disclosure.

[0057] Figure 17 is illustrated a battery pack according to a fourth embodiment of the present disclosure. Detailed Embodiments

[0058] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before that, it should be noted that the terms or words used in this specification and claims should not be construed in their ordinary or dictionary meanings, but rather based on the principle that the inventor can appropriately define the concept of the term to best describe his / her invention, and be construed in a meaning and concept consistent with the technical concept of the present invention.

[0059] Therefore, it should be understood that the embodiments described herein and the configurations illustrated in the drawings are only the most preferred embodiments of the present disclosure, and are not intended to exhaust the technical concept of the present invention, and there may be various equivalents and modifications that can replace them at the time of filing.

[0060] In addition, when describing the present invention, in cases where a detailed description of a related known configuration or feature would obscure the essence of the present invention, such detailed description is omitted.

[0061] Since the embodiments of the present disclosure are provided to more fully explain the present disclosure to those of ordinary skill in the art, for clarity, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically shown. Therefore, the size or ratio of each component does not necessarily indicate its actual size or ratio.

[0062] The present disclosure relates to a battery pack containing a plurality of battery cell assemblies, characterized in that the battery pack has a protrusion having a structure for pressing the upper part of the contained battery cell assemblies.

[0063] Figures 5 to 12 Relates to a battery pack according to a first embodiment of the present disclosure, Figures 13 to 15 Relates to a battery pack according to a second embodiment of the present disclosure, Figure 16 Relates to a battery pack according to a third embodiment of the present disclosure, and Figure 17 Relates to a battery pack according to a fourth embodiment of the present disclosure.

[0064] Hereinafter, specific embodiments of the battery pack of the present disclosure will be described in detail with reference to the drawings. As a reference, unless otherwise defined, relative positioning names such as front and back or up and down used in the following description are intended to assist in understanding the present disclosure and refer to the orientation shown in the drawings.

[0065] In addition, the battery cell assemblies of the present disclosure may be in the form of storing pouch-type battery cells as Figure 1 shown, or in the form of storing prismatic battery cells as Figure 2 shown, but for convenience, the description will focus on the form of storing Figure 1 pouch-type battery cells.

[0066] (First Embodiment)

[0067] Figure 5 Illustrates a battery pack according to a first embodiment of the present disclosure.

[0068] The battery pack includes a battery pack housing 100 and an upper housing 200. The battery cell assemblies 300 are disposed in the battery pack housing 100, and the upper housing 200 is coupled to the battery pack housing 100 to cover the upper part of the battery cell assemblies 300 disposed in the battery pack housing 100.

[0069] The battery cell assemblies 300 accommodated in the battery pack of the present disclosure are characterized in that an opening hole 321 is formed on one side and a protection sheet 340 covers the opening hole 321.

[0070] Figure 6 Illustrates the battery cell assemblies 300 of the present disclosure, and Figure 7 Illustrates the protection sheet 340 being removed from the Figure 6 battery cell assemblies 300.

[0071] The battery cell assembly 300 includes a battery cell stack 310 and a module frame 320. The battery cell stack 310 includes a plurality of battery cells, and the module frame 320 surrounds at least one side of the battery cell stack 310.

[0072] As Figure 6 shown, the battery cell assembly 300 may further include an end plate 330. The end plate 330 protects the battery cell stack 310 accommodated therein from external impacts and the like, and the end plate 330 has external terminals electrically connected to the battery cell stack 310.

[0073] As Figure 7 shown, the module frame 320 includes a plurality of opening holes 321, and the plurality of opening holes 321 are opened to expose the internal battery cell stack 310 to the outside.

[0074] * The purpose of forming the opening holes 321 is to prevent the battery cell assembly 300 from exploding due to an increase in the pressure of the gas (g) inside the battery cell assembly 300 when high-temperature gas (g) is generated due to thermal runaway of the stored battery cell stack 310. In other words, the opening holes 321 serve as channels for the gas (g) generated by thermal runaway of the battery cell stack 310 to escape to the outside.

[0075] The opening holes 321 are formed on the module frame 320 located at the upper part of the battery cell assembly 300 relative to Figure 7 .

[0076] The opening holes 321 can be formed in either a circular shape or a polygonal shape.

[0077] The battery cell assembly 300 of the present disclosure further includes a protection sheet 340, and the protection sheet 340 is attached to the surface of the module frame 320 to cover the opening holes 321.

[0078] The protection sheet 340 covers the side of the module frame 320 where the opening holes 321 are formed to restrict the escape of flame and spark particles and the like through the opening holes 321. In addition, in the case of thermal runaway of any battery cell assembly in the accommodated battery cell assembly 300, the protection sheet 340 is used to restrict the entry of flame and gas into the opening holes 321 of other normal battery cell assemblies 300.

[0079] The protection sheet 340 preferably includes heat-resistant and flame-retardant materials so as not to be damaged by high-temperature gas (g) and not to be burned by flame.

[0080] In addition, the protection sheet 340 preferably includes materials having electrical insulation properties.

[0081] The protection sheet 340 can be a non-porous structure that does not allow gas to pass through, or it can be a porous structure including a plurality of holes that selectively allow gas to pass through.

[0082] A protective sheet 340 with a non-porous structure is attached to seal the opening hole of the battery cell assembly. Therefore, in the case of the battery cell assembly 300 to which the protective sheet 340 is usually attached, it is difficult for gas, flame, etc. to pass through the opening hole 321.

[0083] The protective sheet 340 has a limit pressure below which the protective sheet 340 will not deform due to external pressure, and when a pressure exceeding the limit pressure is applied, the protective sheet 340 may be damaged. For example, as described above, when the pressure inside the battery cell assembly 300 reaches the limit pressure range, the protective sheet 340 sealing the opening hole 321 can be partially broken to release gas and flame. In this case, the protective sheet 340 can have a fracture line applied to it to intentionally open the expected area first.

[0084] The porous protective sheet 340 allows the gas (g) generated by the thermal runaway of the battery cell to pass through, but does not allow the spark particles that may be generated together with the gas (g) to pass through.

[0085] The battery pack housing 100 includes a substrate 110 that supports the lower part of the battery cell assembly 300 and side beams 120 that are coupled to the edges of the substrate 110 to support the side parts of the battery cell assembly 300.

[0086] In addition, the battery pack housing 100 can include a cross beam 130 that has a lower end coupled to the substrate 110 to partition the internal space.

[0087] A plurality of battery cell assemblies 300 can be separately arranged and placed in the internal space of the battery pack housing 100 partitioned by the cross beam 130 and the like. In this case, as Figure 5 shown, each battery cell assembly 300 is arranged such that the opening hole 321 and the protective sheet 340 are on the upper surface.

[0088] The upper housing 200 is coupled to the upper ends of the side beams 120 of the battery pack housing 100 such that the upper part of the battery cell assembly 300 disposed inside the battery pack housing 100 is covered, as Figure 5 shown.

[0089] The protective sheet 340 can be attached to the surface of the module frame 320 by an adhesive or glue, etc. However, when the pressure of the gas (g) is very large and exceeds the adhesion force, it may come off from the module frame 320. In other words, when the pressure of the gas (g) is large, the protective sheet 340 may peel off from the surface of the module frame 320 and may not function to filter spark particles, flame, etc.

[0090] As described above, the battery pack of the present disclosure is characterized in that a structure is added that can press the protective sheet 340 against the module frame 320 to prevent the protective sheet 340 from being removed from the surface of the module frame 320.

[0091] Specifically, the upper housing 200 includes a protrusion 210 at its lower end, and the protrusion 210 presses against the upper part of the battery cell assembly 300 disposed in the battery pack housing 100.

[0092] Figure 8 is a bottom perspective view of the upper housing 200.

[0093] Refer to Figure 8 , and a plurality of protrusions 210 are formed at the lower end of the upper housing 200.

[0094] Each of the protrusions 210 is in the form of a column with a flat end and protrudes from the surface of the upper housing 200 by a predetermined length.

[0095] In addition to the shape shown above, the protrusion 210 can also be in the form of a downwardly protruding projection. That is to say, the protrusion 210 can be any shape that can fully press the upper part of the battery cell assembly 300.

[0096] Figure 9 The upper housing 200 is illustrated using hidden lines so that the protrusion 210 is visible from Figure 5 the battery pack.

[0097] The protrusions 210 are formed at positions corresponding to each of the battery cell assemblies 300.

[0098] Preferably, when the upper housing 200 is fully coupled to the battery pack housing 100, the protrusion 210 extends sufficiently to press the upper part of each battery cell assembly 300. Therefore, the protective sheet 340 attached to the module frame 320 of the battery cell assembly 300 can press the lower end of the protrusion 210 and maintain the attachment.

[0099] However, the opening hole 321 of the battery cell assembly 300 should not be completely blocked by the protrusion 210. If the protrusion 210 blocks the opening hole 321, in the case of thermal runaway of the battery cell, the gas (g) inside the battery cell assembly 300 may not escape smoothly, which may lead to an explosion.

[0100] Figure 10 Illustrates Figure 9 the state where the upper housing 200 and the battery pack housing 100 are coupled together.

[0101] The protrusions 210 are formed at the lower end of the upper housing 200 to correspond to the positions where the opening holes 321 of the battery cell assemblies 300 are not provided, as Figure 10 shown.

[0102] Figure 11 is a simplified cross-sectional view of the battery pack in which one of the battery cell assemblies 300 is disposed.

[0103] Reference Figure 11 Each of the protrusions 210 formed at the lower end of the upper case 200 presses the module frame 320 at the non-positioned opening hole 321 in the battery cell assembly 300.

[0104] Figure 12 Illustrated is the migration of gas (g) in the battery pack when the battery cell stack 310 is in thermal runaway Figure 11 of the battery pack.

[0105] Reference Figure 12 The gas (g) rising upward from the battery cell stack 310 passes through the opening hole 321 and the protective sheet 340 and travels between the upper case 200 and the battery cell assembly 300. That is, the gas (g) can travel between the plurality of protrusions 210 inserted between the upper case 200 and the battery cell assembly 300 and is then discharged to the outside.

[0106] The battery pack of the present disclosure further includes a discharge hole (not shown) formed to communicate with the internal space to allow the gas (g) generated inside to be discharged to the outside.

[0107] Therefore, the battery pack of the present disclosure can allow the high-temperature gas (g) discharged through the opening hole 321 of the battery cell assembly 300 to be discharged to the outside through the discharge hole.

[0108] The discharge hole may be formed on one side of the side beam 120 of the battery pack housing 100 or may be formed on one side of the upper case 200.

[0109] (Second Embodiment)

[0110] The shape of the opening hole 321 of the battery cell assembly 300 accommodated in the battery pack of the present disclosure may be a slit shape. That is, the opening hole 321 may be elongated in one direction.

[0111] Figure 13 Illustrated is a battery pack according to the second embodiment of the present disclosure, Figure 14 illustrated is the battery cell assembly 300 accommodated in Figure 13 and Figure 15 illustrated is the protective sheet 340 removed from the Figure 14 battery cell assembly 300.

[0112] Reference Figures 13 to 15 The opening hole 321 is formed to extend along the longitudinal direction d4 of the battery cell assembly 300.

[0113] The opening hole 321 may have a shape extending along the width direction d3 of the battery cell assembly 300 in addition to the illustrated shape.

[0114] (Third Embodiment)

[0115] The protrusion 210 included in the battery pack of the present disclosure can extend in any direction.

[0116] Figure 16 Illustrated is an upper case 200 included in a battery pack according to a third embodiment of the present disclosure.

[0117] Refer to Figure 16 , the protrusion 210 is formed to extend along the width direction d1 of the battery pack. Although not shown, the opening hole 321 of the cell assembly 300 is preferably also formed in a shape corresponding to the shape of the protrusion 210.

[0118] (Fourth Embodiment)

[0119] The protrusion 210 included in the battery pack of the present disclosure can extend in any direction.

[0120] Figure 17 Illustrated is an upper case 200 included in a battery pack according to a fourth embodiment of the present disclosure.

[0121] Refer to Figure 17 , the protrusion 210 is formed to extend along the longitudinal direction d2 of the battery pack. Although not shown, the opening hole 321 of the cell assembly 300 is preferably also formed in a shape corresponding to the shape of the protrusion 210.

[0122] The present disclosure has been described in more detail above with reference to the drawings and embodiments. However, it should be understood that the configurations shown in the drawings or the embodiments described herein are only one embodiment of the present invention, do not represent all the technical concepts of the present invention, and there can be various equivalents and modifications that can replace them when this application is filed.

[0123] [Description of Reference Numerals]

[0124] 10: (Prior Art) Battery Pack Case

[0125] 20: (Prior Art) Cell Assembly

[0126] 21: (Prior Art) End Plate

[0127] 22: (Prior Art) Module Frame

[0128] 23: (Prior Art) Opening Hole

[0129] 24: (Prior Art) Cell

[0130] 25: (Prior Art) Cell Stack

[0131] 26: (Prior Art) Electrode Lead

[0132] 100: Battery Pack Case

[0133] 110: Substrate

[0134] 120: Side beam

[0135] 130: Cross beam

[0136] 200: Upper housing

[0137] 210: Protrusion

[0138] 300: Battery cell assembly

[0139] 310: Battery cell stack

[0140] 320: Module frame

[0141] 321: Opening hole

[0142] 330: End plate

[0143] 340: Protective sheet

[0144] g: Gas

[0145] d1: Width direction of the battery pack

[0146] d2: Longitudinal direction of the battery pack

[0147] d3: Width direction of the battery cell assembly

[0148] d4: Longitudinal direction of the battery cell assembly

Claims

1. A battery pack containing a battery cell assembly, the battery pack comprising: A battery pack housing, wherein the battery cell assembly is placed in the battery pack housing; as well as an upper housing, the upper housing being coupled to the battery pack housing to cover an upper portion of the battery cell assembly disposed inside the battery pack housing, wherein: The upper case includes a protrusion at a lower end, the protrusion pressing the upper portion of the cell assembly seated in the battery pack case.

2. The battery pack according to claim 1, wherein: The battery core assembly comprises: A battery cell stack, the battery cell stack comprising a plurality of battery cells; and A module frame surrounds at least one side of the battery cell stack.

3. The battery pack according to claim 2, wherein: The module frame includes an opening hole that is opened to expose the battery cell stack in the module frame to the outside.

4. The battery pack according to claim 3, wherein: The opening hole is formed in any one of a circular shape and a polygonal shape.

5. The battery pack according to claim 3, wherein: The opening hole extends along at least one of a longitudinal direction and a width direction of the battery cell assembly.

6. The battery pack according to claim 3, wherein: The battery cell assembly also includes: A protection sheet is attached to a surface of the module frame to cover the opening hole.

7. The battery pack according to claim 6, wherein: The protrusion of the upper case is formed in a position where the opening hole of the battery cell assembly is not provided.

8. The battery pack according to claim 6, wherein: The opening hole is formed on the module frame located on the upper portion of the battery cell assembly.

9. The battery pack according to claim 6, wherein: The protection sheet is a porous structure including a plurality of pores that selectively allow gas to pass therethrough.

10. The battery pack according to claim 6, wherein: The protective sheet is a structure in which no holes are formed to prevent gas from passing therethrough.

11. The battery pack according to claim 6, wherein: The protection sheet has electrical insulation properties.

12. The battery pack according to claim 6, wherein: The protective sheet has heat resistance and flame retardancy.

13. The battery pack according to claim 1, wherein: The projections are in the form of flat-ended posts.

14. The battery pack according to claim 1, wherein: The protrusion is in the form of a downwardly projecting projection.

15. The battery pack according to claim 1, wherein: The protrusion extends in at least one of a longitudinal direction and a width direction of the upper case.

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