Liquid injection port cover, battery cell comprising liquid injection port cover and battery module

Abstract

The present disclosure provides a battery cell, comprising: a battery cell housing having an accommodating space formed therein and comprising a housing main body and a cover plate covering an open end of the housing main body; the electrode assembly is arranged in the battery cell shell; an electrode terminal provided in the case main body; the liquid injection opening cover covers a liquid injection opening formed in the cover plate, and the cover plate comprises a step part which is sunken from the outer side surface of the cover plate to the inner side of the battery cell shell; and a recessed space formed in at least a part of a periphery of the step portion and recessed from an inner side surface of the cap plate to an outer side of the cell case, the injection port cap including: a cap main body mounted on the step portion and covering the injection port; and a protruding portion extending from the cap body to be inserted into the liquid injection port, the recessed space having a shape overlapping at least a portion of the cap body when the cap body is projected in a side direction of the cap body.

Description

Technical Field

[0001] This disclosure relates to an inlet cap for covering the inlet of a rechargeable and discharging battery cell (secondary battery), a battery cell including the inlet cap, and a battery module. Background Technology

[0002] Unlike primary batteries, secondary batteries offer the convenience of being rechargeable and discharging, making them a popular choice as a power source for various mobile devices, electric vehicles, energy storage devices, and more.

[0003] Secondary battery cells can be manufactured as pouch-type or can-type cells. Pouch-type cells have a structure in which electrode assemblies are housed inside a flexible cell casing (pouch). Can-type cells have a structure in which electrode assemblies are housed inside a rigid cell casing (can), and can be configured as cylindrical cells, prismatic batteries, coin-shaped cells, etc. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The battery cell contains an electrolyte and electrode assembly inside its casing. An injection port for injecting the electrolyte can be formed on the casing. After the electrolyte is injected into the battery cell casing, the injection port can be sealed with an injection port cap.

[0006] In existing technologies, to seal the injection port, a method of inserting a ball into the injection port or a method of welding a flat sealing cap to cover the injection port is used. However, with existing technologies, there is a problem that the injection port cap does not detach when the internal pressure of the battery cell rises, and the maximum internal pressure it can withstand is small.

[0007] In recent years, as the battery capacity of products containing battery cells (such as automobiles and energy storage systems) has increased, the size of the battery cells has also increased. This increases the internal pressure of the battery cells, making it easier for the filler cap to detach from the filler port or break.

[0008] According to one aspect of this disclosure, a liquid filling cap capable of increasing the ultimate internal pressure of the liquid filling cap, a battery cell including the liquid filling cap, and a battery module can be provided.

[0009] According to one aspect of this disclosure, a liquid filling cap that can prevent breakage of the liquid filling cap and improve the stability of the battery cell, a battery cell including the liquid filling cap, and a battery module can be provided.

[0010] The liquid filling port cap, the battery cell including the liquid filling port cap, and the battery module disclosed herein can be widely used in electric vehicles, battery charging stations, and other green technology fields such as solar power generation and wind power generation that utilize batteries. Furthermore, the liquid filling port cap, the battery cell including the liquid filling port cap, and the battery module disclosed herein can be used in eco-friendly electric vehicles and hybrid vehicles that prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0011] (II) Technical Solution

[0012] The battery cell according to this disclosure may include: a battery cell housing having an internal receiving space, and including a housing body and a cover plate covering an open end of the housing body; an electrode assembly disposed in the receiving space of the battery cell housing; an electrode terminal disposed in the housing body and electrically connected to the electrode assembly; and a liquid inlet cap covering a liquid inlet formed on the cover plate, the cover plate including: a stepped portion recessed from the outer side of the cover plate toward the inner side of the battery cell housing; a recessed space formed in at least a portion of the periphery of the stepped portion and recessed from the inner side of the cover plate toward the outer side of the battery cell housing, the liquid inlet cap including: a cap body mounted on the stepped portion and covering the liquid inlet; a protrusion extending from the cap body to insert into the liquid inlet, the recessed space having a shape that overlaps with at least a portion of the cap body when the cap body is projected along the lateral direction of the cap body.

[0013] According to one embodiment, the cover body may include a wing that protrudes laterally beyond the protrusion, and the recessed space may overlap at least a portion of the wing in the lateral direction of the cover body.

[0014] According to one embodiment, the stepped portion may include a first portion having the injection port and a second portion disposed outside the first portion. The second portion may include an inclined surface extending from the first portion toward the outside of the cell housing. The recessed space may have a shape that gradually widens toward the inside of the cell housing in the portion opposite to the second portion.

[0015] According to one embodiment, the wing may include a first surface that contacts the first portion and a second surface that contacts the second portion, the second surface including an inclined surface that is inclined relative to the first surface.

[0016] According to one embodiment, the side of the protrusion and the inner side of the injection port can be configured to contact each other or to contact each other when the cover plate deforms.

[0017] According to one embodiment, the contact surface between the protrusion and the injection port can be set to be closer to the center of the injection port cap than the center of the welded portion between the injection port cap and the cover plate.

[0018] According to one embodiment, the cover plate has a circular plate shape, and the injection port may be formed at the center of the cover plate.

[0019] According to one embodiment, the cover body may include: a wing that protrudes laterally beyond the protrusion; and a recess that is recessed from the cover body opposite to the protrusion.

[0020] According to one embodiment, the maximum thickness of the central region of the injection port cap can be between 0.8 and 1.2 times the maximum thickness of the wing.

[0021] According to one embodiment, the maximum thickness of the wing may be greater than the maximum thickness of the protrusion.

[0022] According to one embodiment, the injection port cap may include a vertical groove, which may be formed by recessing along the thickness direction of the injection port cap on at least one of the two sides of the injection port cap in the thickness direction.

[0023] According to one embodiment, the maximum thickness of the central region of the injection port cap can be more than twice the thickness of the cap plate.

[0024] According to one embodiment, the thickness of the protrusion may be more than one times the thickness of the cover plate.

[0025] According to one embodiment, the protrusion of the injection port cap may include an insertion groove, which is formed by recessing around the side periphery of the injection port cap along the side direction of the injection port cap, and the inner side of the injection port is inserted into the insertion groove.

[0026] According to one embodiment, the battery cell housing may include: a housing body including side walls and end plates; and a cover plate covering the open end of the housing body, wherein the side walls are integrally formed with the end plates, and the electrode terminals are riveted to the end plates.

[0027] According to the present disclosure, the liquid injection port cover is formed on a cover plate of a battery cell. The liquid injection port cover may include: a cover body, which is mounted on a recessed step portion of the cover plate and covers the liquid injection port; a protrusion extending from the cover body to insert into the liquid injection port; the cover body includes: a wing portion protruding laterally beyond the protrusion portion; and a recessed portion formed from the cover body facing the protrusion portion opposite to the protrusion portion.

[0028] According to one embodiment, the maximum thickness of the central region of the injection port cap has a value between 0.8 and 1.2 times the maximum thickness of the wing.

[0029] According to one embodiment, the wing may include: a first surface that forms a step with the protrusion; and a second surface that extends from the first surface in the thickness direction of the cover body, the second surface including an inclined surface that is inclined relative to the first surface.

[0030] According to one embodiment, the maximum thickness of the wing may be greater than the maximum thickness of the protrusion.

[0031] According to one embodiment, the injection port cap may include a vertical groove, which is formed by recessing on at least one of the two sides of the injection port cap along the thickness direction of the injection port cap.

[0032] The battery module according to this disclosure may include: a plurality of battery cells; and a module housing for accommodating the plurality of battery cells, at least one of the plurality of battery cells including: a cell housing having an internal accommodating space and including a housing body and a cover plate covering an open end of the housing body; an electrode assembly disposed in the accommodating space of the cell housing; an electrode terminal disposed in the housing body and electrically connected to the electrode assembly; and a liquid inlet cap covering a liquid inlet formed on the cover plate, the cover plate including: a stepped portion recessed from the outer side of the cover plate toward the inner side of the cell housing; a recessed space formed in at least a portion of the periphery of the stepped portion and recessed from the inner side of the cover plate toward the outer side of the cell housing, the liquid inlet cap including: a cap body mounted on the stepped portion and covering the liquid inlet; a protrusion extending from the cap body to insert into the liquid inlet, the recessed space having a shape that overlaps with at least a portion of the cap body when the cap body is projected along the lateral direction of the cap body.

[0033] (III) Beneficial Effects

[0034] According to one embodiment of this disclosure, the limit internal pressure of the injection port cap can be increased.

[0035] According to one embodiment of this disclosure, breakage of the filling cap can be prevented and the stability of the battery cell can be improved. Attached Figure Description

[0036] Figure 1 This is a perspective view of a battery cell according to an embodiment.

[0037] Figure 2yes Figure 1 The image shows an exploded perspective view of the battery cell.

[0038] Figure 3 It is along Figure 1 A cross-sectional view taken from the I-I' line.

[0039] Figure 4 As shown Figure 2 The three-dimensional view of the lower surface of the battery cell shown in the figure illustrates the state in which the liquid filling port cap is detached.

[0040] Figure 5 It is shown Figure 4 A three-dimensional view of the injection port cap being engaged.

[0041] Figure 6 It is along Figure 4 A cross-sectional view taken from line II-II'.

[0042] Figure 7 It is along Figure 5 A cross-sectional view taken from line III-III'.

[0043] Figure 8 It is shown Figure 7 A cross-sectional view of the injection port cap in the welded state.

[0044] Figure 9 and Figure 10 This is a cross-sectional view showing the forces acting on the cover plate and the injection port cap. Figure 9 The image shows the state of the cover plate before it deformed. Figure 10 The state of the cover plate after deformation is shown.

[0045] Figure 11 This is a schematic diagram showing the forces acting on an arched structure.

[0046] Figure 12 It is shown Figure 8 A cross-sectional view of a variant embodiment.

[0047] Figure 13 It is shown Figure 8 A cross-sectional view of another variant embodiment.

[0048] Figure 14 It is shown Figure 13 Cross-sectional view of the middle cover plate 110b after deformation.

[0049] Figure 15 This is a perspective view of a battery module according to one embodiment.

[0050] Explanation of reference numerals in the attached figures:

[0051] 100: Battery cell; 110: Battery cell casing

[0052] 110a: Main body of the casing; 110b: Cover plate

[0053] 111: Side wall; 111a: End

[0054] 112: End plate 112a: Through hole

[0055] 113: Main body of the slab; 114: Step section

[0056] 114a: Part One; 114b: Part Two

[0057] 115: Injection port; 115a: Inner side.

[0058] 116: Recessed space; 116a: First internal surface

[0059] 116b: Second internal face; 116c: Third internal face

[0060] 117: Outer step portion; 118: Outer recessed space

[0061] 119: Exhaust guide section; 120: Electrode assembly

[0062] 120a: Main body; 120b: Electrode tabs

[0063] 121: First electrode; 121a: First electrode tab

[0064] 122: Second electrode; 122a: Second electrode tab

[0065] 123: Diaphragm; 131: Current collector

[0066] 140: Electrode terminal; 141: Outer portion

[0067] 142: Insertion part 143: Inner part

[0068] 150: Injection port cap; 151: Cap body

[0069] 152: Recessed part; 153: Wing part

[0070] 153a: Page 1 153b: Page 2

[0071] 154: Protrusion 154a: Protrusion Surface

[0072] 154b: Side view; 155: Central area

[0073] 156: Vertical slot; 157: Insertion slot

[0074] 161: Washer; 163: Insulating component

[0075] 200: Battery module; 210: Module housing

[0076] T1: Thickness of the cover plate

[0077] T2: Maximum thickness of the central area of ​​the injection cap

[0078] T3: Maximum thickness of the wing

[0079] T4: Maximum thickness of the protrusion

[0080] TC: Overall thickness of the filling port cap

[0081] W: Welded section; WC: Center of the welded section Detailed Implementation

[0082] The same reference numerals or symbols used in the accompanying drawings indicate parts or components that perform substantially the same function. For ease of explanation and understanding, the same reference numerals or symbols will also be used in different embodiments. That is, even if components with the same reference numerals are shown in multiple figures, the multiple figures do not necessarily represent the same embodiment.

[0083] In the following description, unless the context clearly indicates otherwise, singular expressions include plural expressions. Terms such as “comprising” or “constituting” should be understood as being intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, without precluding the presence or additional possibilities of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0084] Additionally, it should be noted that in the following descriptions, terms such as upper side, upper part, lower side, lower part, side, front part, and rear part are based on the direction shown in the figure. If the direction of the corresponding object changes, it can be described in different ways.

[0085] Furthermore, in this specification and claims, terms including ordinal numbers such as "first" and "second" may be used to distinguish components. These ordinal numbers are used to distinguish identical or similar components, and the meaning of the terms should not be interpreted restrictively by using these ordinal numbers. For example, the order of use or arrangement of components combined with these ordinal numbers should not be interpreted restrictively by these ordinal numbers. These ordinal numbers may be used interchangeably as needed.

[0086] The present disclosure will now be described in detail with reference to the accompanying drawings. However, these are merely examples, and the present disclosure is not limited to the specific embodiments described herein.

[0087] Figure 1This is a perspective view of a battery cell 100 according to an embodiment. Figure 2 yes Figure 1 An exploded perspective view of the battery cell 100 shown. Figure 3 It is along Figure 1 A cross-sectional view taken from the I-I' line.

[0088] Reference Figures 1 to 3 According to one embodiment of the present disclosure, the battery cell 100 may include: a battery cell housing 110 having an internal accommodating space S, and including a housing body 110a and a cover plate 110b covering the open end of the housing body 110a; an electrode assembly 120 disposed in the accommodating space S of the battery cell housing 110; an electrode terminal 140 disposed on the housing body 110a and electrically connected to the electrode assembly 120; and a liquid injection port cap 150 covering the liquid injection port 115 formed on the cover plate 110b.

[0089] The battery cell 100 according to this disclosure can be composed of a cylindrical battery cell, but is not limited thereto. This disclosure uses a cylindrical battery cell as an example to describe a battery cell 100 according to one embodiment.

[0090] The cell housing 110 may have an internal accommodating space S. The cell housing 110 may include a housing body 110a and a cover plate 110b covering the open end 111a of the housing body 110a. The cell housing 110 may include: a housing body 110a, including sidewalls 111 and end plates 112; and a cover plate 110b, covering the open end of the housing body 110a. The accommodating space S can be defined as the internal space enclosed by the housing body 110a and the cover plate 110b. The accommodating space S of the cell housing 110 can accommodate the electrode assembly 120 and the electrolyte.

[0091] The housing body 110a may include a sidewall 111 having an internal accommodating space S and an end plate 112 having a through hole 112a. The accommodating space S may be formed by the sidewall 111 and the end plate 112 of the housing body 110a.

[0092] In one embodiment, the battery cell 100 may be a cylindrical battery cell. In this case, the housing body 110a may have a cylindrical shape with one end 111a open. The housing body 110a may have a hollow cylindrical shape including a circular cross-section. However, this disclosure is not limited to cylindrical battery cells, and may also be applied to prismatic battery cells.

[0093] The sidewall 111 may have a tubular shape, and the end plate 112 may have a plate shape that covers one end of the receiving space S (e.g., the top side).

[0094] The sidewall 111 may have a circular tubular shape. The end plate 112 may have at least a partially flat plate shape. The thicknesses of the end plate 112 and the sidewall 111 can be varied in various ways within the housing body 110a. For example, the end plate 112 and the sidewall 111 may have the same thickness, but the thickness of the end plate 112 may be greater than the thickness of the sidewall 111. The housing body 110a may contain metallic materials such as aluminum or aluminum alloys, but the material of the housing body 110a can be varied.

[0095] like Figures 1 to 3 As shown, the sidewall 111 and end plate 112 of the housing body 110a can be integrally formed. For example, the housing body 110a can be formed into the shape of the sidewall 111 and end plate 112 integrally formed by deep drawing a sheet of metal. If the housing body 110a is integrally formed, there is no need for the process of joining the sidewall 111 and end plate 112, thus making it easier to manufacture the housing body 110a and / or the battery cell 100 and improving machinability.

[0096] However, the housing body 110a of this disclosure is not limited to a structure in which the side wall 111 and the end plate 112 are integrally formed. The side wall 111 and the end plate 112 can also be manufactured separately and then joined or bonded to each other by welding or pressing.

[0097] A through hole 112a may be formed on the end plate 112 of the housing body 110a. The through hole 112a can be used to connect the electrode terminal 140. The housing body 110a may have a circular cross-section, and the through hole 112a may be formed in the center of the end plate 112. In this case, the electrode terminal 140 connected to the through hole 112a may be located in the center of the end plate 112.

[0098] The cover plate 110b may cover the open end 111a of the housing body 110a. The cover plate 110b may be coupled to the housing body 110a. For example, the cover plate 110b may be welded or crimped to the end 111a of the housing body 110a.

[0099] The cover plate 110b can cover the receiving space S from the opposite side of the end plate 112.

[0100] An injection port 115 for injecting electrolyte into the housing body 110a may be formed on the cover plate 110b. The injection port 115 may be formed in the center of the plate body 113 of the cover plate 110b, but its position or size may be varied. After the electrolyte is injected, the injection port 115 may be sealed by the injection port cap 150.

[0101] The cover plate 110b may include: a stepped portion 114 recessed from the outer side of the cover plate 110b toward the inner side of the cell housing 110; and a recessed space 116 formed in at least a portion of the periphery of the stepped portion 114 and recessed from the inner side of the cover plate 110b toward the outer side of the cell housing 110.

[0102] Electrode assembly 120 can be disposed within the receiving space S of cell housing 110. Electrode assembly 120 may include a positive electrode, a negative electrode, and a separator 123. The positive and negative electrodes may each include a current-collecting foil (or metal foil) and a mixture layer coated on at least one side of the current-collecting foil. The mixture layer may contain an active material. Separator 123 may be sandwiched between the positive and negative electrodes to electrically insulate them. The positive electrode, negative electrode, and separator 123 may be repeatedly arranged to form electrode assembly 120. As an example, electrode assembly 120 may have a winding shape in which the positive electrode, separator 123, and negative electrode are stacked. However, electrode assembly 120 is not limited to a winding structure. For example, electrode assembly 120 may have a stacking shape, a zigzag-folding shape, or a stack-folding shape.

[0103] The electrode assembly 120 may include a first electrode 121 and a second electrode 122 of different polarities. As an example, the first electrode 121 may be a positive electrode and the second electrode 122 may be a negative electrode, or vice versa.

[0104] The electrode assembly 120 may include a body 120a arranged with a first electrode 121 and a second electrode 122 separated by a diaphragm 123, and electrode tabs 120b extending from the first electrode 121 or the second electrode 122. The body 120a may include a coated portion coated with an active material, and the electrode tabs 120b may include an uncoated portion without active material. The electrode tabs 120b may have a shape that overlaps or bends in a predetermined configuration.

[0105] The electrode tab 120b may include a first electrode tab 121a extending from the first electrode 121 and a second electrode tab 122a extending from the second electrode 122. The first electrode tab 121a may include an uncoated portion of the first electrode 121, and the second electrode tab 122a may include an uncoated portion of the second electrode 122.

[0106] The electrode assembly 120 is connected to the current collector 131, which can be welded to the electrode terminal 140 of the cell 100 and electrically connected to the electrode terminal 140.

[0107] The first electrode tab 121a can be electrically connected to the electrode terminal 140 via the current collector 131. The first electrode tab 121a can be electrically connected to the current collector 131. As an example, the first electrode tab 121a and the current collector 131 can be electrically connected by welding or the like. The current collector 131 can be electrically connected to the electrode terminal 140 via welding or the like.

[0108] The second electrode tab 122a can be electrically connected to at least one of the cover plate 110b and the side wall 111 of the housing body 110a. Figure 3 The diagram shows that the second electrode tab 122a is directly electrically connected to the cover plate 110b, but a current collector can also be separately provided between the second electrode tab 122a and the cover plate 110b.

[0109] Electrode terminals 140 may be disposed on the housing body 110a and electrically connected to the electrode assembly 120. Electrode terminals 140 may engage with through holes 112a in the end plate 112. At least a portion of the electrode terminals 140 is exposed to the outside of the housing body 110a.

[0110] Electrode terminal 140 can be electrically connected to electrode assembly 120. When electrode terminal 140 is connected to the positive terminal of electrode assembly 120, electrode terminal 140 can correspond to the positive terminal, and vice versa.

[0111] The electrode terminal 140 can be riveted into the through hole 112a of the housing body 110a. The electrode terminal 140 can be inserted into the through hole 112a of the end plate 112 and then riveted to it. The electrode terminal 140 can be riveted onto the end plate 112 of the housing body 110a. The electrode terminal 140 can have an integral rivet shape.

[0112] The electrode terminal 140 may include: an outer portion 141 disposed on the outer side (upper side) of the end plate 112; an insertion portion 142 extending from the outer portion 141 toward the electrode assembly 120 and passing through the through hole 112a; and an inner portion 143 extending from the insertion portion 142 and disposed on the inner side (lower side) of the end plate 112. The outer portion 141 may be disposed on the outer side of the housing body 110a, and the inner portion 143 may be disposed in the receiving space S of the housing body 110a. The inner portion 143 may have a shape that extends radially outward toward the housing body 110a by pressure deformation. The end plate 112 may be disposed between the outer portion 141 and the inner portion 143. The outer diameter of the outer portion 141 and the outer diameter of the inner portion 143 may be greater than the diameter of the through hole 112a, and the outer diameter of the insertion portion 142 may be smaller than the diameter of the through hole 112a. The outer diameter of the outer portion 141 may be smaller than the outer diameter of the housing body 110a. The outer diameter of the outer portion 141 can be set according to the welding space between the outer portion 141 and the busbar connected to the outer portion 141.

[0113] A gasket 161 may be provided between the electrode terminal 140 and the end plate 112 to insulate the electrode terminal 140 from the end plate 112. The gasket 161 may be disposed between the electrode terminal 140 and the through hole 112a. The gasket 161 may include an electrically insulating material. The gasket 161 serves as a sealing component between the electrode terminal 140 and the end plate 112.

[0114] If the electrode terminal 140 is riveted with the washer 161 positioned outside the electrode terminal 140, the washer 161 can be positioned between the electrode terminal 140 and the end plate 112. The washer 161 can seal and / or insulate between the electrode terminal 140 and the end plate 112.

[0115] An electrically insulating component 163 may be provided between the current collector 131 and the cell housing 110 to provide electrical insulation between them. As an example, the insulating component 163 may be provided between the current collector 131 and the end plate 112. The shape or location of the insulating component 163 may be varied.

[0116] The filler cap 150 can cover the filler port 115 formed on the cover plate 110b. After the electrolyte is injected into the housing body 110a through the filler port 115, the filler cap 150 can seal the filler port 115. The filler cap 150 can be combined with the cover plate 110b while covering the filler port 115. As an example, the filler cap 150 can be welded to the cover plate 110b. The filler port 115 can be circular in shape, and correspondingly, the filler cap 150 can also include a circular cross-section.

[0117] Below, we will refer to Figures 4 to 14 The filling port cap 150 and the cover plate 110b that is combined with the filling port cap 150 will be described.

[0118] Figure 4 As shown Figure 2 The perspective view of the lower surface of the battery cell 100 shown in the figure illustrates the state in which the liquid injection port cap 150 is detached. Figure 5 It is shown Figure 4 A three-dimensional view of the injection port cap 150 in the assembled state. Figure 6 It is along Figure 4 A cross-sectional view taken from line II-II'. Figure 7 It is along Figure 5 A cross-sectional view taken from line III-III'. Figure 8 It is shown Figure 7 A cross-sectional view of the injection port cap 150 in the welded state. Figure 4 and Figure 5 It is Figure 2 A cross-sectional view shown by flipping it up and down. Figures 6 to 8 It is Figure 3 A cross-sectional view shown by flipping it up and down.

[0119] Reference Figures 4 to 8 The cover plate 110b may include: a stepped portion 114 recessed from the outer side of the cover plate 110b toward the inner side of the cell housing 110; and a recessed space 116 formed in at least a portion of the periphery of the stepped portion 114 and recessed from the inner side of the cover plate 110b toward the outer side of the cell housing 110. The cover plate 110b may have a shape in which the stepped portion 114 and the recessed space 116 are formed on the plate body 113.

[0120] The step portion 114 can be located at the center of the cover plate 110b, and the recessed space 116 can be located further radially outward than the step portion 114. The center of the cover plate 110b can be provided with an injection port 115, which can be located at the step portion 114.

[0121] The cover plate 110b may include a plate body 113. When viewed from the outside of the cover plate 110b, the plate body 113 can form a recessed space for the liquid injection cap 150 to be installed through the step portion 114. When viewed from the inside of the cover plate 110b, a recessed space 116 can be formed through the step portion 114.

[0122] The stepped portion 114 may include a first portion 114a having a liquid injection port 115 and a second portion 114b disposed outside the first portion 114a. The second portion 114b may include an inclined surface extending from the first portion 114a toward the outside of the cell housing 110. The stepped portion 114 may have a shape that widens toward the outside of the cell housing 110. The liquid injection port 115 may have a shape that extends through the first portion 114a of the stepped portion 114. The liquid injection port 115 may be formed at the center of the cover plate 110b.

[0123] By forming a step portion 114 on the cover plate 110b, a recessed space is formed on the inner side of the cover plate 110b. When viewed from the inside of the housing body 110a, the recessed space 116 may have a shape that is recessed towards the outside of the housing body 110a. The recessed space 116 may have an annular shape to surround the periphery of the injection port 115.

[0124] The recessed space 116 may have a shape that widens towards the inside of the cell housing 110 in the portion opposite to the second portion 114b.

[0125] The recessed space 116 may include a first inner surface 116a corresponding to the second portion 114b of the stepped portion 114 and a second inner surface 116b extending radially outward from the first inner surface 116a. The recessed space 116 may further include a third inner surface 116c extending from the second inner surface 116b toward the inner side of the cell housing 110. The first inner surface 116a may be defined as the inner surface of the first portion 114a of the stepped portion 114 in the cover plate 110b. The first inner surface 116a and the third inner surface 116c are formed at an angle, and the second inner surface 116b may be perpendicular to the axial direction of the cell housing 110.

[0126] The filler cap 150 can cover the filler port 115 formed on the cover plate 110b of the cell 100. The filler cap 150 may include: a cap body 151, mounted on the stepped portion 114 and covering the filler port 115; and a protrusion 154 extending from the cap body 151 to insert into the filler port 115. The cap body 151 can be defined as a portion disposed on the outside of the cover plate 110b. The protrusion 154 may have a shape extending from the cap body 151 toward the inside of the cell housing 110. The stepped portion 114 may have a first height ( Figure 7 H1 in the middle), so that the injection port cap 150 does not protrude outward of the step portion 114.

[0127] The protrusion 154 may include a protruding surface 154a facing the receiving space S of the cell housing 110 and a side surface 154b facing the lateral direction.

[0128] The protrusion 154 may have a shape that allows it to be inserted into the injection port 115, thus enabling the protrusion 154 and the injection port 115 to contact each other. The side surface 154b of the protrusion 154 and the inner side surface 115a of the injection port 115 may be configured to contact each other or to contact each other when the cover plate 110b is deformed. For example, the diameters of the protrusion 154 and the injection port 115 may each have a size that allows the side surface 154b of the protrusion 154 and the inner side surface 115a of the injection port 115 to contact each other. Alternatively, it may be configured such that even when the side surface 154b of the protrusion 154 is inserted into the injection port 115 and does not contact the inner side surface 115a of the injection port 115, the inner side surface 115a of the injection port 115 will contact the side surface 154b of the protrusion 154 when the cover plate 110b is deformed.

[0129] When the side 154b of the protrusion 154 contacts the inner side 115a of the injection port 115, the stepped portion 114 of the cover plate 110b and the side 154b of the protrusion 154 can interfere with each other, thus limiting the deformation of the cover plate 110b. That is, when internal pressure is applied to the injection port cover 150, the side 154b of the protrusion 154 and the inner side 115a of the injection port 115 interfere with each other, thereby limiting the deformation of the cover plate 110b. This prevents the injection port cover 150 from detaching.

[0130] The recessed space 116 of the cover plate 110b can have a shape that overlaps with at least a portion of the cover body 151 when the cover body 151 is projected along its lateral direction. That is, the recessed space 116 can have a shape that is recessed to a height corresponding to at least a portion of the side surface of the cover body 151. (Refer to...) Figure 7 The height of the recessed space 116, i.e., the second height H2, can be defined as the height from the inner side of the first portion 114a of the step portion 114 to the second inner surface 116b of the recessed space 116. When the cover body 151 is projected along the side direction of the cover body 151, the overlap height between the recessed space 116 and the cover body 151 can correspond to Figure 7 The third height H3 is shown. When the height of the recessed space 116 is set such that the side of the cover body 151 overlaps with the recessed space 116, the cover body 151 may be subjected to a horizontal component force when the internal pressure of the cell housing 110 rises.

[0131] The cover body 151 may include a wing 153 that protrudes laterally beyond the protrusion 154, and a recessed space 116 may overlap at least a portion of the wing 153 in the lateral direction of the cover body 151. That is, when the cover body 151 is projected along its lateral direction, the recessed space 116 may have a shape that is recessed to a height corresponding to at least a portion of the side of the wing 153. When the wing 153 and the recessed space 116 are configured to overlap in the height direction of the recessed space 116, the cover body 151 may be subjected to a horizontal component force when the internal pressure of the cell housing 110 increases. When the horizontal component force acts on the cover body 151, the limit internal pressure value that the filler cap 150 can withstand from the internal pressure of the cell 100 can be increased. This can prevent the filler cap 150 from detaching from the filler port 115.

[0132] At least a portion of the outer surface of the wing 153 contacts the stepped portion 114. The stepped portion 114 may include a first portion 114a and a second portion 114b. The wing 153 may include a first surface 153a that contacts the first portion 114a and a second surface 153b that contacts the second portion 114b. The second surface 153b may correspond to a side surface of the wing 153. The second surface 153b of the wing 153 may include an inclined surface that is inclined relative to the first surface 153a. The second surface 153b of the wing 153 may have an inclination corresponding to the second portion 114b of the stepped portion 114. That is, the second surface 153b of the wing 153 may include an inclined surface extending from the first surface 153a of the wing 153 toward the outside of the cell housing 110, so that the second surface 153b of the wing 153 contacts the second portion 114b of the stepped portion 114.

[0133] The cover body 151 includes: a wing 153 that protrudes laterally beyond the protrusion 154; and a recess 152 that is recessed from the cover body opposite to the protrusion 154. The recess 152 may be disposed opposite to the protrusion 154 in the thickness direction of the cover body 151.

[0134] The overall thickness TC of the filling port cap 150 can be the sum of the maximum thickness T3 of the wing 153 and the maximum thickness T4 of the protrusion 154. The maximum thickness T2 of the central region 155 of the filling port cap 150 can have the same or similar value as the maximum thickness T3 of the wing 153. The maximum thickness T2 of the central region 155 of the filling port cap 150 can be defined as the distance between the protruding surface 154a of the protrusion 154 and the outer surface of the recess 152.

[0135] The material of the cover plate 110b may include plated carbon steel (carbon content less than 0.8%) or stainless steel. The material of the filling port cap 150 may include plated carbon steel (carbon content less than 0.8%) or stainless steel.

[0136] The filling port cap 150 can be manufactured by cutting a long cylindrical raw material into a predetermined length and then forging the cut coin-shaped material. The filling port cap 150 may include a protrusion 154, a recess 152, and a wing 153, which can be formed by forging. When the recess 152 is formed on the filling port cap 150, the maximum thickness T2 of the central region 155 of the filling port cap 150 and the maximum thickness T3 of the wing 153 can be set to be the same or similar.

[0137] The maximum thickness T2 of the central region 155 of the injection port cap 150 can be between 0.8 and 1.2 times the maximum thickness T3 of the wing 153. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be between 0.8 and 1.2 times, 0.85 and 1.15 times, 0.9 and 1.1 times, or 0.95 and 1.05 times the maximum thickness T3 of the wing 153. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be more than 0.8 times, more than 0.85 times, more than 0.9 times, or more than 0.95 times the maximum thickness T3 of the wing 153. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be the same as the maximum thickness T3 of the wing 153. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be less than 1.2 times, less than 1.15 times, less than 1.1 times, or less than 1.05 times the maximum thickness T3 of the wing 153.

[0138] The depth of the recess 152 can be the same as or similar to the height of the protrusion 154. The recess 152 and the protrusion 154 can face opposite directions in the central region 155 of the cover body 151.

[0139] When the maximum thickness T2 of the central region 155 of the injection port cap 150 and the maximum thickness T3 of the wing 153 have the same or similar values, the injection port cap 150 can be easily manufactured by forging. That is, if the thickness varies greatly during forging, it is difficult to process the injection port cap 150. However, according to this embodiment, since the maximum thickness T2 of the central region 155 of the injection port cap 150 and the maximum thickness T3 of the wing 153 have the same or similar values, not only is the power consumption for forging small, but the defect rate can also be reduced.

[0140] The filler cap 150 may include a vertical groove 156, which is recessed along the thickness direction of the filler cap 150 on at least one of its two sides in the thickness direction. When the filler cap 150 is manufactured by forging, a protrusion corresponding to the vertical groove 156 can be formed on the forging die. When the vertical groove 156 is formed on the filler cap 150, the filler cap 150 can be easily manufactured by forging. Although Figures 6 to 8 The diagram shows a structure in which vertical grooves 156 are formed on both sides of the injection port cover 150, but vertical grooves 156 may also be formed on only one side of the two sides of the injection port cover 150.

[0141] The maximum thickness T3 of the wing 153 can be greater than the maximum thickness T4 of the protrusion 154. Furthermore, when the maximum thickness T3 of the wing 153 is greater than the maximum thickness T4 of the protrusion 154, the height H3 of the overlapping area between the wing 153 and the recessed space 116 increases, which may increase the lateral component of the pressure exerted on the wing 153 by the internal pressure of the cell housing 110. This increases the limit of internal pressure that the filler cap 150 can withstand from the internal pressure of the cell 100 and prevents the filler cap 150 from detaching from the filler port 115. Additionally, when the maximum thickness T3 of the wing 153 increases, the contact area between the second surface 153b of the wing 153 and the second portion 114b of the stepped portion 114 increases, thereby increasing the strength of the weld W.

[0142] The thickness T4 of the protrusion 154 can correspond to the depth of the portion of the filler cap 150 inserted into the filler port 115. The thickness T4 of the protrusion 154 can be at least 0.9 times the thickness T1 of the cover plate 110b.

[0143] For example, the thickness T4 of the protrusion 154 can be more than twice the thickness T1 of the cover plate 110b. Since the protrusion 154 of the filler cap 150 is the part inserted into the filler port 115, when the thickness T4 of the protrusion 154 is more than twice the thickness T1 of the cover plate 110b, the protrusion 154 can extend beyond the filler port 115 and protrude into the inside of the cell housing 110. When the thickness T4 of the protrusion 154 is greater than or equal to the thickness T1 of the cover plate 110b, the contact area or contactable area between the side surface 154b of the protrusion 154 and the inner side surface 115a of the filler port 115 can be increased. Therefore, when internal pressure acts on the filler cap 150, the side surface 154b of the protrusion 154 and the inner side surface 115a of the filler port 115 interfere with each other, thereby preventing the filler cap 150 from detaching.

[0144] Between the outer surface of the recess 152 and the protruding surface 154a of the protrusion 154, the maximum thickness T2 of the central region 155 of the injection port cap 150 can be greater than the thickness T1 of the cover plate 110b. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be more than twice the thickness T1 of the cover plate 110b. The protrusion 154 of the injection port cap 150 can be inserted into the injection port 115, and the cap body 151 of the injection port cap 150 can be disposed on the injection port 115. According to one embodiment, since the thick injection port cap 150 covers the injection port 115, the injection port cap 150 can increase the rigidity of the injection port 115 and the step portion 114 formed on the cover plate 110b. The maximum thickness T2 of the central region 155 of the injection port cap 150 can be less than 10 times, less than 7 times, less than 5 times, or less than 3 times the thickness T1 of the cover plate 110b. When the maximum thickness T2 of the central region 155 of the liquid injection port cap 150 is too large relative to the thickness T1 of the cover plate 110b, the volume occupied by the liquid injection port cap 150 increases, thereby reducing the energy density of the battery cell 100.

[0145] The cover plate 110b may include an outer step portion 117 located radially outward of the recessed space 116. The outer step portion 117 of the cover plate 110b may be connected to the third inner surface 116c of the recessed space 116. The outer step portion 117 may be electrically connected to the second electrode tab. The outer step portion 117 may be in direct contact with the second electrode tab or may be electrically connected via a separate current collector. The outer step portion 117 may be the area where the cover plate 110b is welded to the second electrode tab. The plate body 113 may include a plurality of mutually spaced outer step portions 117. When a plurality of outer step portions 117 are formed, the plate body 113 will have an uneven shape, thereby improving the rigidity of the cover plate 110b.

[0146] The cover plate 110b may have an outer recessed space 118 formed radially outward of the outer step portion 117. Multiple outer step portions 117 may be located between the recessed space 116 and the outer recessed space 118.

[0147] The battery cell 100 may include a vent guide 119, which opens when the pressure inside the battery cell housing 110 increases, allowing gas inside the battery cell housing 110 to escape to the outside. The vent guide 119 may be formed on the cover plate 110b. The vent guide 119 may have a structure that breaks when the pressure inside the battery cell housing 110 exceeds a preset pressure. The vent guide 119 may be composed of a weak portion that is easily broken under the preset pressure, and its thickness is thinner than the surrounding area. As an example, the vent guide 119 may include a notch or groove formed on the plate body 113.

[0148] The exhaust guide 119 may have a closed curve shape, but is not limited to this. For example, if at least a portion of the cover 110b can be opened, it may have an open curve shape, and its shape may also be varied.

[0149] Reference Figure 8 The weld portion W can be formed along the periphery of the injection port cap 150 between the plate body 113 of the cap 110b and the cap body 151 of the injection port cap 150. When the periphery of the injection port cap 150 has a circular shape, the weld portion W can form a circular weld line. The weld portion W can be formed at the portion where the wing 153 of the cap body 151 contacts the step portion 114. In the completed welding state, the weld seam of the weld portion W can have a height that does not protrude beyond the space formed by the step portion 114. For example, as... Figure 8 As shown, the welded part W may not protrude beyond the outermost surface of the cover plate 110b.

[0150] The contact surface between the protrusion 154 and the injection port 115 can be positioned closer to the center of the injection port cap 150 than the center WC of the welded portion W between the injection port cap 150 and the cover plate 110b. Since the contact surface between the protrusion 154 and the injection port 115 is located inside the center WC of the welded portion W, the contact surface between the protrusion 154 and the injection port 115 can be separated from the center WC of the welded portion W. In this case, when the cover plate 110b deforms under internal pressure, the torque acting on the welded portion W can be reduced. Therefore, the force exerted on the welded portion W by the deformation of the cover plate 110b is reduced, thereby preventing the injection port cap 150 from detaching.

[0151] Figure 9 and Figure 10 This is a cross-sectional view showing the forces acting on the cover plate 110b and the injection port cap 150. Figure 9 The image shows the state of cover plate 110b before deformation. Figure 10 The state of cover plate 110b after deformation is shown. Figure 11 This is a schematic diagram showing the forces acting on an arched structure.

[0152] Reference Figures 9 to 10 The cover plate 110b may have a recessed space 116 formed around the injection port 115. The recessed space 116 may have a shape that overlaps with at least a portion of the cover body 151 when projected along the side direction of the cover body 151. If the height of the recessed space 116 is set such that the side of the cover body 151 overlaps with the recessed space 116, then when the internal pressure of the cell housing 110 rises, a force F2, including a horizontal component, can act on the cover body 151.

[0153] Reference Figure 11The keystone B1 of the arched structure has an inclined surface, so the first vertical force Fa acting on the keystone B1 can be transmitted to the adjacent voussoir B2. The second force Fb acting on the voussoir B2 in contact with the keystone can include a horizontal component, and the third force Fc acting between the voussoir B2 can also include a horizontal component. In this way, the first vertical force Fa acting on the arched structure can be converted into a horizontal component or a horizontal reaction force, thereby maintaining the stable shape of the arched structure.

[0154] In the embodiments of this disclosure, since a recessed space 116 is formed on the cover plate 110b, a force F2, which has a lateral component similar to the keystone of an arched structure, can act on the first inner surface 116a of the recessed space 116. Under the same internal pressure, when comparing the case with the recessed space 116 and the case without the recessed space 116, the force F1 acting on the cover plate 110b and the filler cap 150 along the axis of the cell housing 110 can be further reduced compared to the case without the recessed space 116. That is, according to one embodiment, since a recessed space 116 is formed on the cover plate 110b, the lateral force acting on the cover plate 110 reduces the force acting in the direction of disengagement of the filler cap 150. Therefore, according to the embodiment, the ultimate internal pressure value that the filler cap 150 can withstand under the internal pressure of the cell 100 will increase. The ultimate internal pressure can be defined as the pressure (force) that the filler cap 150 can withstand without detaching from the filler port 115.

[0155] Reference Figure 10 The center of the cover plate 110b bulges and deforms due to the internal pressure of the cell housing 110, thereby forming a predetermined angle θ tilt on the outer surface of the cover plate 110b. When the cover plate 110b deforms, the side 154b of the protrusion 154 interferes with the inner side 115a of the injection port 115 to limit the deformation of the cover plate 110b. This prevents the injection port cap 150 from detaching.

[0156] Furthermore, according to one embodiment, the contact surface between the protrusion 154 and the injection port 115 is positioned closer to the center of the injection port cap 150 than the center WC of the welded portion W between the injection port cap 150 and the cover plate 110b. This reduces the torque acting on the welded portion W. Consequently, the force acting on the welded portion W is reduced due to the deformation of the cover plate 110b, thereby preventing the injection port cap 150 from detaching.

[0157] Figure 12It is shown Figure 8 A cross-sectional view of a variant embodiment.

[0158] Figure 8 In one embodiment, the injection port cap 150 may include a vertical groove 156 recessed along the thickness direction of the injection port cap 150 on at least one of its two sides in the thickness direction. In contrast, Figure 12 In the variant embodiment shown, the injection port cap 150 may not include the vertical groove 156. In this disclosure, the two sides of the injection port cap 150 along the thickness direction may have a flat shape. That is, the outer side of the recess 152 and the protruding surface 154a of the protrusion 154 may have a flat shape.

[0159] right Figures 4 to 8 In the description of the embodiments, the rest of the content, except for the vertical slot 156, can also be applied. Figure 12 A variant embodiment.

[0160] Figure 13 It is shown Figure 8 A cross-sectional view of another variant embodiment. Figure 14 It is shown Figure 13 A cross-sectional view of the deformed state of the cover plate 110b in the middle.

[0161] and Figure 8 Compared to the embodiments shown, Figure 13 and Figure 14 The difference in the variant embodiment shown is that an insertion groove 157 is formed on the injection port cap 150. Figures 4 to 8 In the description of the embodiments, the content other than the differences can also be applied. Figure 13 and Figure 14 A variant embodiment.

[0162] The protrusion 154 of the filler cap 150 may include an insertion groove 157 formed by recessing the periphery of the side surface 154b along the lateral direction of the filler cap 150. The inner side surface 115a of the filler port 115 can be inserted into the insertion groove 157. The insertion groove 157 may be formed on at least a portion of the periphery of the protrusion 154. The insertion groove 157 may prevent the filler cap 150 from disengaging from the filler port 115. For example, as Figure 14 As shown, even when the cover plate 110b is deformed, it can still maintain the state of being connected to the injection port cover 150.

[0163] Figure 15 This is a perspective view of a battery module according to one embodiment.

[0164] Reference Figure 15According to one embodiment, a battery module 200 may include a plurality of battery cells 100 and a module housing 210 that accommodates the plurality of battery cells 100.

[0165] Reference Figures 1 to 14 At least one of the cells 100 described herein may be used in at least one of the plurality of cells 100 provided in the battery module 200.

[0166] When the battery module 200 of this disclosure includes multiple battery cells 100, its specific type is not limited. For example, the battery module 200 of this disclosure can be defined as including a battery pack or an energy storage device, etc.

[0167] The module housing 210 can provide space for accommodating multiple battery cells 100. The module housing 210 may include a housing body 211 forming the space for accommodating multiple battery cells 100 and a housing cover 215 covering the upper side of the multiple battery cells 100.

[0168] The above description is merely an example of applying the principles of this disclosure, and other configurations may be included without departing from the scope of the invention. Furthermore, the above embodiments can be implemented by deleting some components, and the embodiments can also be combined with each other.

Claims

1. A battery cell comprising: a battery cell case in which an accommodation space is formed inside, and including a case main body and a cover plate covering an open end portion of the case main body; an electrode assembly disposed in the accommodation space of the battery cell case; an electrode terminal disposed in the case main body and electrically connected to the electrode assembly; and a liquid injection port cover covering a liquid injection port formed in the cover plate, the cover plate including: a stepped portion recessed from an outer side of the cover plate toward an inner side of the battery cell case; and a recessed space formed in at least a portion of a periphery of the stepped portion and recessed from an inner side of the cover plate toward an outer side of the battery cell case, the liquid injection port cover including: a cover main body mounted on the stepped portion and covering the liquid injection port; and a protruding portion extending from the cover main body to be inserted into the liquid injection port, the recessed space having a shape that overlaps at least a portion of the cover main body when the cover main body is projected in a side direction of the cover main body.

2. The battery cell according to claim 1, wherein the cover main body includes a wing portion protruding more outward in the side direction than the protruding portion, the recessed space overlaps at least a portion of the wing portion in the side direction of the cover main body.

3. The battery cell according to claim 2, wherein the stepped portion includes a first portion in which the liquid injection port is formed, and a second portion disposed outward of the first portion, the second portion includes an inclined surface inclined toward an outer side of the battery cell case from the first portion, a portion of the recessed space opposite to the second portion has a shape that gradually widens toward an inner side of the battery cell case.

4. The battery cell according to claim 3, wherein the wing portion includes a first surface in contact with the first portion, and a second surface in contact with the second portion, the second surface includes an inclined surface inclined with respect to the first surface.

5. The battery cell according to claim 1, wherein a side surface of the protruding portion and an inner side surface of the liquid injection port are disposed to be in contact with each other, or are disposed to be in contact with each other when the cover plate is deformed.

6. The battery cell according to claim 5, wherein a contact surface of the protruding portion and the liquid injection port is disposed closer to a center of the liquid injection port cover than a center portion of a welding portion between the liquid injection port cover and the cover plate.

7. The battery cell according to claim 1, wherein the cover main body includes: a wing portion protruding more outward in the side direction than the protruding portion; and a recessed portion recessed from a surface of the cover main body opposite to the protruding portion toward the protruding portion.

8. The battery cell according to claim 7, wherein a maximum thickness of a central region of the liquid injection port cover has a value between 0.8 and 1.2 times a maximum thickness of the wing portion.

9. The battery cell according to claim 7, wherein the maximum thickness of the wing portion has a value greater than a maximum thickness of the protruding portion.

10. The battery cell according to any one of claims 1 to 9, wherein the liquid injection port cover includes a vertical groove recessed in at least one of both side surfaces in a thickness direction of the liquid injection port cover in the thickness direction of the liquid injection port cover. ​ 11. The battery cell according to any one of claims 1 to 9, wherein a maximum thickness of a central region of the injection port cover has a value of more than twice a thickness of the cover plate.

12. The battery cell according to any one of claims 1 to 9, wherein a thickness of the protruding portion has a value of more than a thickness of the cover plate.

13. The battery cell according to any one of claims 1 to 9, wherein the protruding portion of the injection port cover includes an insertion groove that is recessed in a side surface direction of the injection port cover along a side surface periphery of the injection port cover, an inner side surface of the injection port is inserted into the insertion groove.

14. The battery cell according to any one of claims 1 to 9, wherein the battery cell case includes a case main body including a side wall and an end plate, and a cover plate covering an open end portion of the case main body, the side wall is integrally formed with the end plate, the electrode terminal is riveted to the end plate.

15. An injection port cover covering an injection port formed in a cover plate of a battery cell, the injection port cover including: a cover main body mounted on a step portion recessed in the cover plate and covering the injection port; a protruding portion extending from the cover main body to be inserted into the injection port, the cover main body includes a wing portion protruding more outward in a side surface direction than the protruding portion, and a recessed portion recessed from a surface of the cover main body opposite to the protruding portion and facing the protruding portion.

16. The injection port cover according to claim 15, wherein a maximum thickness of a central region of the injection port cover has a value of between 0.8 and 1.2 times a maximum thickness of the wing portion.

17. The injection port cover according to claim 15, wherein the wing portion includes a first surface forming a step with the protruding portion, and a second surface extending from the first surface in a thickness direction of the cover main body, the second surface includes an inclined surface inclined with respect to the first surface.

18. The injection port cover according to any one of claims 15 to 17, wherein a maximum thickness of the wing portion has a value greater than a maximum thickness of the protruding portion.

19. The injection port cover according to any one of claims 15 to 17, wherein the injection port cover includes a vertical groove recessed in a thickness direction of the injection port cover along at least one of both side surfaces in the thickness direction of the injection port cover.

20. A battery module including: a plurality of battery cells; and a module case accommodating the plurality of battery cells, at least one of the plurality of battery cells includes: a battery cell case internally formed with an accommodation space and including a case main body and a cover plate covering an open end portion of the case main body; an electrode assembly disposed in the accommodation space of the battery cell case; an electrode terminal disposed in the case main body and electrically connected to the electrode assembly; and an injection port cover covering an injection port formed in the cover plate, the cover plate includes a step portion recessed from an outer side surface of the cover plate toward an inner side of the battery cell case, and a recessed space formed in at least a portion of a periphery of the step portion and recessed from an inner side surface of the cover plate toward an outer side of the battery cell case. ​ The injection port cover includes a cover main body installed at the stepped portion and covering the injection port, a protruding portion extending from the cover main body to be inserted into the injection port, The recessed space has a shape overlapping at least a portion of the cover main body when the cover main body is projected in a lateral direction of the cover main body.

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