Battery cell, battery case, and method for manufacturing battery cell

Abstract

A battery cell according to an embodiment of the present invention may include: an electrode assembly; and a battery case including a first cover part and a second cover part covering both side surfaces of the electrode assembly in the thickness direction. Terrace forming parts may be molded to be recessed at both edges of at least one of the first cover part and the second cover part, and the first cover part and the second cover part may be sealed with each other in the terrace forming parts.

Description

Battery cell, battery case and battery cell manufacturing method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0051538, filed April 17, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a battery case having an unformed cup portion for accommodating an electrode assembly, a battery cell including the same, and a method for manufacturing the same.

[0005] Unlike primary batteries, secondary batteries can be recharged and discharged, making them suitable for a wide range of applications, including digital cameras, mobile phones, laptops, and hybrid vehicles. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries.

[0006] Among these secondary batteries, much research is being conducted on lithium secondary batteries with high energy density and discharge voltage, and recently, lithium secondary batteries are manufactured as flexible pouch-type battery cells and used by connecting multiple batteries to form a module.

[0007] A pouch-type battery cell uses a pouch-type battery case as an outer material that surrounds an electrode assembly, wherein the electrode assembly has a structure in which a positive electrode plate and a negative electrode plate filled with an electrode active material and a separator interposed between the positive electrode plate and the negative electrode plate are laminated. A positive electrode tab is formed on one side of the positive electrode plate, and a negative electrode tab is formed on one side of the negative electrode plate. The tabs are connected to an electrode lead, thereby connecting to an external circuit. This electrode assembly is sealed by the pouch-type battery case as an outer material.

[0008] A typical pouch-type battery case can be manufactured by forming a cup-shaped storage portion through a forming process to accommodate an electrode assembly in a pouch sheet. In the forming process, a mold is used to pressurize a portion of the pouch sheet to form the storage portion. However, there is a concern that the corner portion (apex portion) of the storage portion may be excessively elongated, resulting in a thin remaining thickness and cracks. Due to these concerns, the depth of the storage portion formed through the forming process is limited by factors such as the elongation of the pouch sheet, and there is a limit to the thickness and capacity of the electrode assembly that can be accommodated in the storage portion.

[0009] In addition, the sealing portion formed by attaching some areas of the pouch-type battery case to each other is formed by attaching areas that were not pressurized to each other during the forming process of the storage portion. Therefore, due to the step between the sealing portion that was not formed and the storage portion that was formed, some areas of the sealing portion extend beyond the width of the storage portion. Such protruding areas are generally referred to as bat ears. The bat ears cause an increase in dead space that does not contribute to the capacity of the secondary battery, which in turn leads to a problem of lowering the energy density of the secondary battery.

[0010] The problem to be solved by the present invention is to provide a battery cell having a high energy density, which can accommodate an electrode assembly having a larger thickness and in which bat ears are not formed.

[0011] Another problem to be solved by the present invention is to provide a battery case included in the battery cell.

[0012] Another problem that the present invention seeks to solve is to provide a method for manufacturing the battery cell.

[0013] A battery cell according to an embodiment of the present invention may include an electrode assembly; and a battery case including a first cover part and a second cover part that cover both thickness-wise sides of the electrode assembly. A terrace forming part may be recessed into both edges of at least one of the first cover part and the second cover part, and the first cover part and the second cover part may be sealed to each other at the terrace forming part.

[0014] The first cover part includes a first edge part where the terrace forming part is not formed, the second cover part includes a second edge part where the terrace forming part is not formed, the first edge part and the second edge part are sealed to each other, and at least one of the first edge part and the second edge part can be folded to face the terrace forming part.

[0015] The above terrace forming part may include a first terrace forming part in which both edges of the first cover part are formed to be sunken; and a second terrace forming part in which both edges of the second cover part are formed to be sunken and are sealed with the first terrace forming part.

[0016] The battery cell may further include an electrode lead connected to the electrode assembly and protruding outward from the battery case. The terrace forming portion may be formed to be concave toward the electrode lead.

[0017] The battery cell may further include an insulating member surrounding a portion of the periphery of the electrode lead and sealing a portion of the terrace forming portion.

[0018] The above terrace forming portion can be opened with respect to the protruding direction of the electrode lead.

[0019] The above terrace forming part may include a sealing surface on which sealing is performed; a first circumferential surface connecting the first cover part or the second cover part and the sealing surface; and a pair of second circumferential surfaces connected to the sealing surface and the first circumferential surface and facing each other.

[0020] The first circumferential surface faces in a direction parallel to the protruding direction of the electrode lead, and the pair of second circumferential surfaces may face each other in the width direction of the electrode lead.

[0021] The battery case may further include a connecting portion that integrally connects the first cover portion and the second cover portion. The connecting portion is formed flat, and a first boundary between the connecting portion and the first cover portion and a second boundary between the connecting portion and the second cover portion may each be foldable.

[0022] When the battery case is unfolded, the gap between the first terrace forming portion and the second terrace forming portion may be equal to the width of the connecting portion.

[0023] The width of the above connecting portion may correspond to the thickness of the above electrode assembly.

[0024] The connecting portion may include a center portion facing the electrode assembly; and an end portion extending from the center portion and connected to the terrace forming portion.

[0025] The above terrace forming portion may include a sealing surface having a seal; a first circumferential surface connecting the first cover portion or the second cover portion and the sealing surface; and a pair of second circumferential surfaces connected to the sealing surface and the first circumferential surface and facing each other. One of the pair of second circumferential surfaces may be connected to the end portion.

[0026] Any one of the pair of second peripheral surfaces may face the end portion and be in contact with or adjacent to the end portion.

[0027] The electrode assembly is positioned between the two terrace forming portions, and the distance between the two terrace forming portions may correspond to either the length or the width of the electrode assembly.

[0028] The length of the above terrace forming portion may correspond to the other of the length or width of the electrode assembly.

[0029] A battery case according to an embodiment of the present invention may be provided to accommodate an electrode assembly. The battery case may include a first cover portion covering one side of the electrode assembly in the thickness direction; and a second cover portion covering the other side of the electrode assembly in the thickness direction. A terrace forming portion may be recessed and formed on both edges of at least one of the first and second covers.

[0030] A method for manufacturing a battery cell according to an embodiment of the present invention can manufacture a battery cell including a battery case including a first cover part and a second cover part, and an electrode assembly accommodated in the battery case. The method for manufacturing a battery cell can include a step of recessing and forming a terrace forming part on both edges of at least one of the first cover part and the second cover part; a step of covering the electrode assembly on both sides in the thickness direction with the first cover part and the second cover part; and a step of sealing the first cover part and the second cover part to each other at the terrace forming part.

[0031] The first cover part and the second cover part may be integrally connected by a connecting part. In the step of bringing the first cover part and the second cover part into contact with each other, the first boundary between the connecting part and the first cover part and the second boundary between the connecting part and the second cover part may each be folded.

[0032] The above battery cell manufacturing method may further include a step of sealing the edges of the first cover portion and the second cover portion where the terrace forming portion is not formed. The step of sealing the edges of the first cover portion and the second cover portion where the terrace forming portion is not formed may include a step of folding at least one of the edges of the first cover portion and the edges of the second cover portion.

[0033] According to a preferred embodiment of the present invention, the first cover part and the second cover part forming the battery case can be sealed to each other at the terrace forming part. That is, with respect to the completed battery cell, the concave side of the terrace forming part can face the outside of the battery case. Therefore, compared to the cup-shaped recessed molded receiving part of a conventional battery case, the terrace forming part can be molded deeper, thereby providing the advantage of being able to accommodate a thick, high-capacity electrode assembly and increasing the energy density of the battery cell.

[0034] Additionally, there is no need to form a cup-shaped, recessed housing to accommodate the electrode assembly in the battery case. Therefore, a portion of the sealing portion of a conventional battery case that protrudes beyond the width of the housing (so-called "bat-ear") is not formed. This has the advantage of increasing the energy density of the battery cell.

[0035] In addition, the configurations according to preferred embodiments of the present invention may include effects that can be easily predicted by those skilled in the art.

[0036] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0037] Figure 1 is an assembly diagram of a battery cell according to a first embodiment of the present invention.

[0038] Fig. 2 is a perspective view showing the battery case illustrated in Fig. 1 in a folded state.

[0039] Figure 3 is a perspective view of the battery case illustrated in Figure 1 viewed from another direction.

[0040] Figure 4 is a side view of a battery cell according to the first embodiment of the present invention.

[0041] Fig. 5 is a modified example of the sealing portion shown in Fig. 4.

[0042] Figure 6 is an assembly diagram of a battery cell according to a second embodiment of the present invention.

[0043] Figure 7 is an assembly diagram of a battery cell according to a third embodiment of the present invention.

[0044] Fig. 8 is a perspective view showing the battery case illustrated in Fig. 7 in a folded state.

[0045] Figure 9 is an assembly diagram of a battery cell according to a fourth embodiment of the present invention.

[0046] Figure 10 is a flowchart of a battery cell manufacturing method according to one embodiment of the present invention.

[0047] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0048] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0049] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0050] In the drawing, each component of a secondary battery according to one embodiment of the present invention is schematically illustrated, and the size of the component or the thickness of the line may be expressed somewhat exaggerated for the convenience of understanding.

[0051] FIG. 1 is an assembly diagram of a battery cell according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the battery case shown in FIG. 1 in a folded state, FIG. 3 is a perspective view of the battery case shown in FIG. 1 viewed from another direction, and FIG. 4 is a side view of a battery cell according to the first embodiment of the present invention.

[0052] A battery cell (1) according to a first embodiment of the present invention includes an electrode assembly (10) and a battery case (100). The battery cell (1) may further include an electrode lead (11) connected to the electrode assembly (10) and protruding outside the battery case (100).

[0053] The electrode assembly (10) may be formed by alternately interposing a plurality of electrodes and separators. That is, each electrode assembly (10) may include a plurality of electrodes and a separator interposed between the plurality of electrodes to mutually insulate the plurality of electrodes.

[0054] The electrode assembly (10) may be of a stack type, a jelly roll type, a stack and folding type, etc., and the type of the electrode assembly (10) is not limited.

[0055] An electrode lead (11) may be connected to the electrode assembly (10). The electrode lead (11) may protrude outside the battery case (100). The electrode lead (11) may act as a passage through which current flows between the electrode assembly (10) and an external load.

[0056] The electrode lead (11) may include a positive lead connected to the positive electrode of the electrode assembly (10) and a negative lead connected to the negative electrode of the electrode assembly (10). As illustrated in FIG. 1, the positive lead and the negative lead may protrude in opposite directions from the electrode assembly (10). However, this is not limited thereto, and the positive lead and the negative lead may also protrude in parallel in the same direction.

[0057] The battery cell (1) may further include an insulating member (12) that surrounds a portion of the periphery of the electrode lead (11) and is sealed with a portion of a terrace forming portion (110) to be described later. The insulating member (12) may insulate the electrode lead (11) and the battery case (100) from each other. In more detail, the insulating member (12) may insulate the electrode lead (11) and the terrace forming portion (110) from each other. The insulating member (12) may be an insulating tape attached to the electrode lead (11), but is not limited thereto.

[0058] Meanwhile, the battery case (100) may be a pouch-type battery case. That is, the battery case (100) may be manufactured by forming a pouch sheet. The pouch sheet may be a laminate sheet including first and second polymer layers positioned at the outermost sides, and a metal layer positioned between the first and second polymer layers. However, the type of the battery case (100) is not limited thereto.

[0059] The following description is basically based on the state in which the battery case (100) is folded (Fig. 2), but may also be related to the state in which the battery case (100) is unfolded (Figs. 1 and 3) as needed, and those skilled in the art will be able to appropriately understand this based on the context or description.

[0060] The battery case (100) may include a first cover part (101) and a second cover part (102) that cover both sides in the thickness direction of the electrode assembly (10).

[0061] The first cover part (101) can cover the electrode assembly (10) on one side in the thickness direction, and the second cover part (102) can cover the electrode assembly (10) on the other side in the thickness direction.

[0062] A terrace forming portion (110) can be sunken-molded on at least one of the two edges of the first cover portion (101) and the second cover portion (102). The terrace forming portion (110) can be formed by a forming process. More specifically, the terrace forming portion (110) can be formed by pressing an edge region of at least one of the first cover portion (101) and the second cover portion (102) having a sheet shape using a mold.

[0063] The concave side of the terrace forming part (110) may face the outside of the battery case (100).

[0064] The two terrace forming portions (110) formed on either side edge of the first cover portion (101) and the second cover portion (102) may face each other in either the longitudinal direction or the width direction of the electrode assembly (10). In addition, each terrace forming portion (110) may be formed to be long in the other direction of the longitudinal direction or the width direction of the electrode assembly (10). For example, as illustrated in FIG. 1, the two terrace forming portions (110) may face each other in the longitudinal direction of the electrode assembly (10), and each terrace forming portion (110) may be formed to be long in the width direction of the electrode assembly (10).

[0065] The electrode assembly (10) may be positioned between the two terrace forming portions (110). The distance between the two terrace forming portions (110) may correspond to either the length or the width of the electrode assembly (10). Here, correspondence may mean the same or similar. Accordingly, the electrode assembly (10) may be fitted between the two terrace forming portions (110), and the empty space within the battery case (100) may be reduced, thereby increasing the energy density of the battery cell (1).

[0066] In addition, the length of each terrace forming portion (110) may correspond to the other of the length or width of the electrode assembly (10). Here, correspondence may mean the same or similar. Accordingly, the electrode assembly (10) can be fitted between the connecting portion (103) and the sealing portion (140) described below, and the empty space within the battery case (100) can be reduced, thereby increasing the energy density of the battery cell (1).

[0067] For example, referring to FIG. 1, the distance between the two terrace forming parts (110) corresponds to the length of the electrode assembly (10), and the length of each terrace forming part (110) may correspond to the width of the electrode assembly (10).

[0068] The terrace forming portion (110) may be formed at a position corresponding to the electrode lead (11). More specifically, the terrace forming portion (110) may be formed concavely toward the electrode lead (11). The electrode lead (11) may be adjacent to the terrace forming portion (110).

[0069] The terrace forming portion (110) may be open with respect to the protruding direction of the electrode lead (11). More specifically, the terrace forming portion (110) may include a sealing surface (111), a first circumferential surface (112), and a second circumferential surface (113).

[0070] The sealing surface (111) may be a surface where sealing is performed. The sealing surface (111) may be a bottom surface formed during forming of the terrace forming portion (110).

[0071] The first circumferential surface (112) can connect the first cover part (101) or the second cover part (102) and the sealing surface (111). The first circumferential surface (112) can be the inner surface of the terrace forming part (110). The first circumferential surface (112) can be formed approximately perpendicular to the sealing surface (111). The first circumferential surface (112) can face a direction parallel to the protrusion direction of the electrode lead (11). That is, the terrace forming part (110) can be open with respect to the direction in which the first circumferential surface (112) faces.

[0072] The second circumferential surface (113) may be provided in a pair facing each other. The pair of second circumferential surfaces (113) may face each other in the width direction of the electrode lead (12). The second circumferential surface (113) may be connected to the sealing surface (111) and the first circumferential surface (112). Like the first circumferential surface (112), the second circumferential surface (113) may connect the first cover part (101) or the second cover part (102) and the sealing surface (111). The second circumferential surface (113) may be formed approximately perpendicular to the sealing surface (111) and the first circumferential surface (112).

[0073] In the present embodiment, as illustrated in FIG. 1, terrace forming parts (110) may be sunken-molded on both sides of the first cover part (101) and the second cover part (102). More specifically, the terrace forming part (110) may include a first terrace forming part (110A) in which both sides of the first cover part (101) are sunken-molded, and a second terrace forming part (110B) in which both sides of the second cover part (102) are sunken-molded.

[0074] The first terrace forming part (110A) and the second terrace forming part (110B) can face each other with the electrode lead (11) therebetween. More specifically, when the first cover part (101) and the second cover part (102) cover the electrode assembly (10) on both sides, the respective sealing surfaces (111) of the first terrace forming part (110A) and the second terrace forming part (110B) can face each other with the electrode lead (11) and the insulating member (12) therebetween.

[0075] The first cover part (101) and the second cover part (102) can be sealed to each other at the terrace forming part (110). In the present embodiment, the first terrace forming part (110A) and the second terrace forming part (110B) can be sealed to each other.

[0076] In more detail, the first terrace forming portion (110A) and the second terrace forming portion (110B) may be partially sealed by being in contact with each other and partially sealed by being in contact with the insulating member (12). Even more specifically, a portion of each of the sealing surface (111) of the first terrace forming portion (110A) and the sealing surface (111) of the second terrace forming portion (110B) may be sealed by being in contact with each other and partially sealed by being in contact with the insulating member (12).

[0077] Accordingly, the electrode lead (11) can pass between the first terrace forming portion (110A) and the second terrace forming portion (110B) and protrude to the outside of the battery case (100).

[0078] The depth of the first terrace forming portion (110A) and the depth of the second terrace forming portion (110B) may be the same. However, this is not limited to the depth of the first terrace forming portion (110A) and the depth of the second terrace forming portion (110B) may be formed differently.

[0079] The sum of the depth of the first terrace forming portion (110A) and the depth of the second terrace forming portion (110B) may correspond to the thickness (t) of the electrode assembly (10). Corresponding may mean identical or similar, and the standard for similarity may be the difference in thickness of the portion where the electrode lead (11) and the insulating member (12) are combined.

[0080] As described above, the battery case (100) according to the present invention may have a terrace forming portion (110) that is recessed and molded. Since the concave side of the terrace forming portion (110) faces the outside of the battery case (100), the limitation on the radius of curvature of the corner portion of the terrace forming portion (110), i.e., the portion where the sealing surface (111), the first circumferential surface (112), and the second circumferential surface (112) meet, may be reduced. Therefore, compared to the recessed-molded receiving portion of a conventional battery case in a cup shape, the terrace forming portion (110) can be molded more deeply. As a result, the battery case (100) according to the present invention has the advantage of being able to accommodate a thick, high-capacity electrode assembly (10) and increasing the energy density of the battery cell (1).

[0081] Meanwhile, the battery case (100) may further include a connecting portion (103) that integrally connects the first cover portion (101) and the second cover portion (102). That is, a battery case (100) including the first cover portion (101), the second cover portion (102), and the connecting portion (103) can be manufactured by forming a single pouch sheet.

[0082] The first boundary (B1) between the connecting portion (103) and the first cover portion (101) and the second boundary (B2) between the connecting portion (103) and the second cover portion (102) can each be folded.

[0083] The connecting portion (103) may extend parallel to the direction in which the two terrace forming portions (110) face each other. For example, the connecting portion (103) may extend parallel to the longitudinal direction of the electrode assembly (10).

[0084] The connecting portion (103) may face the electrode assembly (10). The connecting portion (103) may be in contact with or adjacent to the electrode assembly (10).

[0085] The width (W) of the connecting portion (103) may correspond to the thickness (t) of the electrode assembly (10). The width (W) of the connecting portion (103) may be constant along the longitudinal direction of the connecting portion (103).

[0086] When the battery case (100) is unfolded, the gap between the first terrace forming portion (110A) and the second terrace forming portion (110B) may be equal to the width (W) of the connecting portion (103). The first terrace forming portion (110A) and the second terrace forming portion (110B) may be connected to the connecting portion (103). In more detail, one second circumferential surface (113) of the first terrace forming portion (110A) and one second circumferential surface (113) of the second terrace forming portion (110B) may be connected to the connecting portion (103).

[0087] The connecting portion (103) can be formed flat. More specifically, the center portion (104) and the end portion (105), which will be described later, can form the same plane. That is, compared to a conventional battery cell, an unnecessarily protruding portion (e.g., bat-ear) from the battery case (100) can be eliminated, and the energy density of the battery cell (1) can be improved.

[0088] The connecting portion (103) may include a center portion (104) and an end portion (105).

[0089] The center portion (104) may face the electrode assembly (10). The center portion (104) may be in contact with or adjacent to the electrode assembly (10). The length of the center portion (104) may be equal to the length or width of the electrode assembly (10).

[0090] The center portion (104) can be connected to the first cover portion (101) and the second cover portion (102). The boundary between the center portion (104) and the first cover portion (101) and the boundary between the center portion (104) and the second cover portion (102) can be folded at approximately 90 degrees.

[0091] The end portion (105) may extend from the center portion (104). A pair of end portions (105) may be provided. A pair of end portions (105) may define both ends of the connecting portion (103).

[0092] The end portion (105) can be connected to the terrace forming portion (110). The length of the end portion (105) can be the same as the width of the terrace forming portion (110).

[0093] One of the pair of second circumferential surfaces (113) of each terrace forming portion (110) can be connected to the end portion (105). More specifically, one of the pair of second circumferential surfaces (113) of the first terrace forming portion (110A) can be connected to one widthwise end of the end portion (105), and one of the pair of second circumferential surfaces (113) of the second terrace forming portion (110B) can be connected to the other widthwise end of the end portion (105).

[0094] Referring to FIG. 2, one of the pair of second circumferential surfaces (113) of each terrace forming portion (110) may face the end portion (105). One of the pair of second circumferential surfaces (113) of each terrace forming portion (110) may be in contact with or adjacent to the end portion (105).

[0095] Meanwhile, referring to FIG. 4, the battery case (100) may be provided with a sealing portion (140) in which the first edge portion (101a) of the first cover portion (101) and the second edge portion (102a) of the second cover portion (102) are sealed to each other.

[0096] The terrace forming portion (110) may not be formed on the first edge portion (101a) and the second edge portion (102a).

[0097] In more detail, the first cover portion (101) may include a first edge portion (101a) on which the first terrace forming portion (110A) is not formed. The second cover portion (102) may include a second edge portion (102a) on which the second terrace forming portion (110B) is not formed.

[0098] The first edge portion (101a) and the second edge portion (102a) can be sealed to each other. That is, the portion where the first edge portion (101a) and the second edge portion (102a) are sealed to each other can be defined as a sealing portion (140).

[0099] The first edge portion (101a) may be located on one side of the first cover portion (101). The second edge portion (102a) may be located on one side of the second cover portion (102). More specifically, the first edge portion (101a) and the second edge portion (102a) may be located on opposite sides of the connecting portion (103). Accordingly, the sealing portion (140) in which the first edge portion (101a) and the second edge portion (102a) are sealed to each other may be located on the opposite side of the connecting portion (103).

[0100] Each terrace forming portion (110) may be connected to the first edge portion (101a) or the second edge portion (102a). More specifically, the first terrace forming portion (110A) may be connected to the first edge portion (101a), and the second terrace forming portion (110B) may be connected to the second edge portion (102a). Even more specifically, one of the pair of second circumferential surfaces (113) of the first terrace forming portion (110A) may be connected to the first edge portion (101a), and one of the pair of second circumferential surfaces (113) of the second terrace forming portion (110B) may be connected to the second edge portion (102a).

[0101] At least one of the first edge portion (101a) and the second edge portion (102a) may be folded. More specifically, at least one of the first edge portion (101a) and the second edge portion (102a) may be folded to face the terrace forming portion (110). At least one of the first edge portion (101a) and the second edge portion (102a) may be folded to contact or be adjacent to the terrace forming portion (110).

[0102] For example, as illustrated in FIG. 4, the first edge portion (101a) and the second edge portion (102a) can each be folded to face the terrace forming portion (110).

[0103] A portion of the folded first edge portion (101a) may be in contact with or adjacent to the second circumferential surface (113) of the first terrace forming portion (110A). A portion of the folded second edge portion (102a) may be in contact with or adjacent to the second circumferential surface (113) of the second terrace forming portion (110B). Another portion of the folded first edge portion (101a) and another portion of the folded second edge portion (102a) may be sealed to each other to form a sealing portion (140).

[0104] One of the pair of second circumferential surfaces (113) of the first terrace forming portion (110A) may be in contact with or adjacent to the connecting portion (103), and the other may be in contact with or adjacent to the folded first edge portion (101a). One of the pair of second circumferential surfaces (113) of the second terrace forming portion (110B) may be in contact with or adjacent to the connecting portion (103), and the other may be in contact with or adjacent to the folded second edge portion (102a).

[0105] Fig. 5 is a modified example of the sealing portion shown in Fig. 4.

[0106] Either the first edge portion (101a) or the second edge portion (102a) can be folded to face the terrace forming portion (110). Hereinafter, a case in which the second edge portion (102a) is folded will be described as an example, as illustrated in FIG. 5.

[0107] A part of the folded second edge portion (102a) may be in contact with or adjacent to the second circumferential surface (113) of the first terrace forming portion (110A), another part may be in contact with or adjacent to the second circumferential surface (113) of the second terrace forming portion (110B), and another part of the folded second edge portion (102a) may be sealed with the first edge portion (101a) to form a sealing portion (140).

[0108] One of the pair of second circumferential surfaces (113) of each of the first terrace forming portion (110A) and the second terrace forming portion (110B) may be in contact with or adjacent to the connecting portion (103), and the other may be in contact with or adjacent to the folded second edge portion (102a).

[0109] Although not shown in FIGS. 4 and 5, the sealing portion (140) may be SSF (Single Side Folding) or DSF (Double Side Folding).

[0110] Figure 6 is an assembly diagram of a battery cell according to a second embodiment of the present invention.

[0111] The second embodiment is identical to the first embodiment described above except that the battery case (100) does not include a connecting portion (103), so the following description will omit overlapping content and focus on the differences.

[0112] In this embodiment, the battery case (100) can be manufactured by separating the first cover portion (101) and the second cover portion (102). That is, the first cover portion (101) and the second cover portion (102) can be manufactured separately by forming a plurality of pouch sheets.

[0113] As previously described, a terrace forming portion (110) may be recessed into the edges of at least one of the first cover portion (101) and the second cover portion (102). In the present embodiment, as illustrated in FIG. 6, a terrace forming portion (110) may be recessed into the edges of each of the first cover portion (101) and the second cover portion (102).

[0114] The first edge portion (101a) may be positioned on both sides of the first cover portion (101). The second edge portion (102a) may be positioned on both sides of the second cover portion (102). Accordingly, a sealing portion (140) (see FIG. 4 or FIG. 5) in which the first edge portion (101a) and the second edge portion (102a) are sealed to each other may be formed on both sides of the battery case (100). The electrode assembly (10) may be positioned between the two sealing portions (140).

[0115] FIG. 7 is an assembly diagram of a battery cell according to a third embodiment of the present invention, and FIG. 8 is a perspective view showing the battery case illustrated in FIG. 7 in a folded state.

[0116] The third embodiment is identical to the first embodiment described above, except that the terrace forming portion (110) is not formed in either the first cover portion (101) or the second cover portion (102). Therefore, the following description will omit overlapping content and focus on the differences.

[0117] In this embodiment, as shown in FIG. 7, a terrace forming portion (110) may be formed by recessing on both edges of the first cover portion (101), and a terrace forming portion (110) may not be formed on the second cover portion (102).

[0118] The first cover part (101) and the second cover part (102) can be sealed to each other at the terrace forming part (110). In the present embodiment, both terrace forming parts (110) of the first cover part (101) can be sealed to both edges of the second cover part (102).

[0119] In more detail, the terrace forming portion (110) of the first cover portion (101) and the two edges of the second cover portion (102) may be sealed by contacting each other at some portions and by contacting the insulating member (12). In even more detail, the sealing surface (111) of the terrace forming portion (110) of the first cover portion (101) and the two edges of the second cover portion (102) may be sealed by contacting each other at some portions and by contacting the insulating member (12).

[0120] Accordingly, the electrode lead (11) can pass between the terrace forming portion (110) of the first cover portion (101) and the second cover portion (102) and protrude to the outside of the battery case (100).

[0121] The depth of the terrace forming portion (110) may correspond to the thickness (t) of the electrode assembly (10). Corresponding may mean identical or similar, and the standard for similarity may be the difference in thickness of the portion where the electrode lead and the insulating member are combined.

[0122] The terrace forming portion (110) can be connected to the connecting portion (103), more specifically, to the end portion (105). More specifically, one of the pair of second circumferential surfaces (113) of the terrace forming portion (110) can be connected to one end in the width direction of the end portion (105).

[0123] One of the pair of second circumferential surfaces (113) of the terrace forming portion (110) may face the end portion (105). One of the pair of second circumferential surfaces (113) of the terrace forming portion (110) may be in contact with or adjacent to the end portion (105).

[0124] However, as with the second embodiment described above, it is also possible for the battery case (100) to not include a connecting portion (103).

[0125] Meanwhile, although not shown in FIG. 8, the battery case (100) may be provided with a sealing portion (140) in which the first edge portion (101a) of the first cover portion (101) and the second edge portion (102a) of the second cover portion (102) are sealed to each other (see FIGS. 4 and 5).

[0126] Figure 9 is an assembly diagram of a battery cell according to a fourth embodiment of the present invention.

[0127] The fourth embodiment is identical to the first embodiment described above, except that the two electrode leads (11) protrude in parallel in the same direction. Therefore, the following description will omit overlapping content and focus on the differences.

[0128] The electrode lead (11) may include a positive lead connected to the positive electrode of the electrode assembly (10) and a negative lead connected to the negative electrode of the electrode assembly (10). In the present embodiment, the positive lead and the negative lead may extend parallel to each other in the same direction.

[0129] Each of the positive electrode leads (11) may be provided with an insulating member (12). However, this is not limited to this, and it is also possible for a single insulating member (12) to surround both of the positive electrode leads (11).

[0130] Hereinafter, for convenience of explanation, the first terrace forming part (110A) formed on one edge of the first cover part (101) is named as 'one first terrace forming part (110A)', and the first terrace forming part (110A) formed on the other edge of the first cover part (101) is named as 'the other first terrace forming part (110A)'. Similarly, the second terrace forming part (110B) formed on one edge of the second cover part (102) is named as 'one second terrace forming part (110B)', and the second terrace forming part (110B) formed on the other edge of the second cover part (102) is named as 'the other second terrace forming part (110B)'.

[0131] The first terrace forming part (110A) and the second terrace forming part (110B) can face each other with the positive electrode lead (11) between them.

[0132] In more detail, when the first cover part (101) and the second cover part (102) cover the electrode assembly (10) on both sides, the respective sealing surfaces (111) of the first terrace forming part (110A) and the second terrace forming part (110B) can face each other with the electrode lead (11) and the insulating member (12) interposed therebetween.

[0133] The first terrace forming portion (110A) and the second terrace forming portion (110B) may be partially sealed by being in contact with each other and partially sealed by being in contact with the insulating member (12). More specifically, a portion of each of the sealing surface (111) of the first terrace forming portion (110A) and the sealing surface (111) of the second terrace forming portion (110B) may be sealed by being in contact with each other and partially sealed by being in contact with the insulating member (12).

[0134] Accordingly, the positive electrode lead (11) can pass between the first terrace forming portion (110A) and the second terrace forming portion (110B) and protrude to the outside of the battery case (100).

[0135] The first terrace forming part (110A) and the second terrace forming part (110B) may face each other. The first terrace forming part (110A) and the second terrace forming part (110B) may contact and seal each other.

[0136] The depth of the first and second terrace forming portions (110A)(110B) may be greater than the depth of the first and second terrace forming portions (110A)(110B). The difference between the sum of the depths of the first and second terrace forming portions (110A)(110B) and the sum of the depths of the first and second terrace forming portions (110A)(110B) may correspond to the thickness of the portion where the electrode lead (11) and the insulating member (12) are combined.

[0137] Meanwhile, as in the second embodiment described above, it is also possible for the battery case (100) to not include a connection portion (103). In addition, as in the third embodiment described above, it is also possible for the terrace forming portion (110) not to be formed in either the first cover portion (101) or the second cover portion (102).

[0138] Figure 10 is a flowchart of a battery cell manufacturing method according to one embodiment of the present invention.

[0139] A battery cell manufacturing method according to one embodiment of the present invention may include a step (S10) (hereinafter, “forming step”) of recessing and forming a terrace forming part (110) on at least one of the opposite edges of a first cover part (101) and a second cover part (102), a step (S20) (hereinafter, “covering step”) of covering the electrode assembly (10) on both sides in the thickness direction with the first cover part (101) and the second cover part (102), and a step (S30) (hereinafter, “sealing step”) of sealing the first cover part (101) and the second cover part (102) to each other at the terrace forming part (110).

[0140] In the above forming step (S10), the terrace forming portion (110) can be formed by a forming process. More specifically, the terrace forming portion (110) can be formed by pressing both sides of at least one of the first cover portion (101) and the second cover portion (102) having a sheet shape using a mold.

[0141] In the above cover step (S20), the concave side of the terrace forming part (110) may face the outside of the battery case (100).

[0142] In particular, when the first cover part (101) and the second cover part (102) are integrally connected by the connecting part (103), the first boundary (B1) between the connecting part (103) and the first cover part (101) and the second boundary (B2) between the connecting part (103) and the second cover part (102) can be folded, respectively. As a result, the center part (104) of the connecting part (103) can face the electrode assembly (10), and the end part (105) of the connecting part (103) can face the terrace forming part (110).

[0143] Hereinafter, the cover step (S20) and the sealing step (S30) will be described as an example in which a terrace forming part (110) is formed in each of the first cover part (101) and the second cover part (102), as in the first, second, and fourth embodiments described above.

[0144] In the cover step (S20), the terrace forming part (110) of the first cover part (101) (i.e., the first terrace forming part (110A)) and the terrace forming part (110) of the second cover part (102) (i.e., the second terrace forming part (110B)) may face each other. In more detail, the first terrace forming part (110A) and the second terrace forming part (110B) may face each other with the electrode lead (11) and the insulating member (12) interposed therebetween.

[0145] In the sealing step (S30), the first terrace forming part (110A) and the second terrace forming part (110B) may be sealed to each other. More specifically, some of the first terrace forming part (110A) and the second terrace forming part (110B) may be sealed to each other, and other parts may be sealed to the insulating member (12).

[0146] Hereinafter, as in the third embodiment described above, the cover step (S20) and the sealing step (S30) will be described as an example in which the terrace forming part (110) is formed in only one of the first cover part (101) and the second cover part (102).

[0147] In the cover step (S20), the terrace forming part (110) can face the edges of both sides of the other one of the first cover part (101) and the second cover part (102).

[0148] In the above sealing step (S30), the terrace forming part (110) may be sealed with both edges of the other one of the first cover part (101) and the second cover part (102). More specifically, a part of the terrace forming part (110) may be sealed with both edges of the other one of the first cover part (101) and the second cover part (102), and another part of the terrace forming part (110) may be sealed with the insulating member (12).

[0149] Meanwhile, the above battery cell manufacturing method may further include a step (S40) (hereinafter, 'additional sealing step') of sealing the edge portions (101a) and (102a) where the terrace forming portion (110) is not formed in the first cover portion (101) and the second cover portion (102) to each other.

[0150] In the above additional sealing step (S40), the edge portion (101a) of the first cover portion (101) (i.e., the first edge portion) and the edge portion (102a) of the second cover portion (102) (i.e., the second edge portion) can be sealed to each other to form a sealing portion (140).

[0151] When the first cover part (101) and the second cover part (102) are integrally connected by the connecting part (103), the sealing part (140) can be located on the opposite side of the connecting part (103) with the electrode assembly (10) interposed therebetween. On the other hand, when the battery case (100) does not include the connecting part (103), the sealing part (140) can be located on both sides of the electrode assembly (10).

[0152] The additional sealing step (S40) may include a process of folding at least one of the edge portion (101a) of the first cover portion (101) (i.e., the first edge portion) and the edge portion (102a) of the second cover portion (102) (i.e., the second edge portion).

[0153] In more detail, in the additional sealing step (S40), at least one of the first edge portion (101a) and the second edge portion (102a) may be folded to face the terrace forming portion (110). In this regard, the description made in relation to the sealing portion (140) in FIGS. 4 and 5 above is referred to.

[0154] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0155] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0156] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0157] [Explanation of symbols]

[0158] 1: Battery cell 10: Electrode assembly

[0159] 11: Electrode lead 12; Insulating member

[0160] 100: Battery case 101: First cover

[0161] 101a: First edge portion 102: Second cover portion

[0162] 102a: Second edge 103: Connection

[0163] 104: Center 105: End

[0164] 110: Terrace forming section 110A: First terrace forming section

[0165] 110B: 2nd terrace forming part 111: Sealing surface

[0166] 112: First circumference 113: Second circumference

[0167] 140: Sealing part

Claims

1. Electrode assembly; and A battery case including a first cover part and a second cover part covering both sides in the thickness direction of the electrode assembly, At least one of the first cover portion and the second cover portion has a terrace forming portion sunken into the edges on both sides, A battery cell in which the first cover part and the second cover part are sealed to each other in the terrace forming part.

2. In paragraph 1, The first cover portion includes a first edge portion in which the terrace forming portion is not formed, The second cover portion includes a second edge portion in which the terrace forming portion is not formed, The first edge portion and the second edge portion are sealed to each other, A battery cell folded so that at least one of the first edge portion and the second edge portion faces the terrace forming portion.

3. In paragraph 1, The above terrace forming part is, A first terrace forming part in which both edges of the first cover part are sunken; and A battery cell including a second terrace forming portion having both edges of the second cover portion sunken and sealed with the first terrace forming portion.

4. In paragraph 1, further comprising an electrode lead connected to the electrode assembly and protruding outside the battery case; The above terrace forming portion is a battery cell formed concavely toward the electrode lead.

5. In paragraph 4, A battery cell further comprising an insulating member surrounding a portion of the periphery of the electrode lead and sealing a portion of the terrace forming portion.

6. In paragraph 4, The above terrace forming portion is a battery cell open with respect to the protruding direction of the electrode lead.

7. In paragraph 4, The above terrace forming part is, Sealing surface where sealing is done; A first circumferential surface connecting the first cover part or the second cover part and the sealing surface; and A battery cell comprising a pair of second peripheral surfaces facing each other and connected to the sealing surface and the first peripheral surface.

8. In paragraph 7, The above first circumferential surface faces in a direction parallel to the protruding direction of the electrode lead, A battery cell in which the pair of second peripheral surfaces face each other in the width direction of the electrode lead.

9. In paragraph 1, The above battery case, It further includes a connecting part that integrally connects the first cover part and the second cover part, The above connection part is formed flat, The first boundary between the connecting portion and the first cover portion and the second boundary between the connecting portion and the second cover portion are each a folded battery cell.

10. In paragraph 9, When the battery case is unfolded, the gap between the first terrace forming portion and the second terrace forming portion is the same as the width of the connecting portion.

11. In paragraph 9, The width of the above connecting portion corresponds to the thickness of the electrode assembly of the battery cell.

12. In paragraph 9, The above connection part, a center portion facing the electrode assembly; and A battery cell including an end portion extending from the center portion and connected to the terrace forming portion.

13. In paragraph 12, The above terrace forming part is, Sealing surface where sealing is done; A first circumferential surface connecting the first cover part or the second cover part and the sealing surface; and It includes a pair of second circumferential surfaces that are connected to the sealing surface and the first circumferential surface and face each other, One of the pair of second peripheral surfaces is a battery cell connected to the end portion.

14. In paragraph 13, A battery cell in which one of the pair of second peripheral surfaces faces the end portion and is in contact with or adjacent to the end portion.

15. In paragraph 1, The above electrode assembly is located between the two terrace forming parts, The distance between the two terrace forming portions corresponds to either the length or width of the electrode assembly, the battery cell.

16. In paragraph 15, The length of the above terrace forming portion corresponds to the other of the length or width of the electrode assembly.

17. In a battery case provided to accommodate an electrode assembly, A first cover part covering one side of the electrode assembly in the thickness direction; and It includes a second cover part that covers the thickness direction side surface of the electrode assembly, A battery case in which a terrace forming portion is recessed and molded on at least one of the two sides of the first cover portion and the second cover portion.

18. A method for manufacturing a battery cell including a battery case including a first cover part and a second cover part, and an electrode assembly accommodated in the battery case, A step of forming a terrace forming portion into the edges of at least one side of the first cover portion and the second cover portion; A step in which the first cover part and the second cover part cover the electrode assembly on both sides in the thickness direction; and A battery cell manufacturing method comprising a step of sealing the first cover part and the second cover part to each other in the terrace forming part.

19. In paragraph 18, The first cover part and the second cover part are connected as one piece by a connecting part, A battery cell manufacturing method in which, in the step of bringing the first cover part and the second cover part into contact with each other, the first boundary between the connecting part and the first cover part and the second boundary between the connecting part and the second cover part are each folded.

20. In paragraph 18, In addition, the step of sealing the edges of the terrace forming portions that are not formed in the first cover portion and the second cover portion is further included. A method for manufacturing a battery cell, wherein the step of sealing the edges of the terrace forming portions that are not formed with each other includes a step of folding at least one of the edge portion of the first cover portion and the edge portion of the second cover portion.

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