Exterior material and battery cell comprising same

Abstract

A battery cell according to an embodiment of the present invention may comprise: an electrode assembly in which a positive electrode and a negative electrode are alternately interleaved with a separator interposed therebetween; and a pouch-type exterior material having a receiving portion recessed so as to accommodate the electrode assembly. The receiving portion may include: a center region; and a pair of end regions disposed on opposite sides of the center region, each having a depth dimension smaller than that of the center region and being asymmetrical to each other.

Description

Exterior material and battery cell including the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0190767 filed on December 19, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a pouch-type outer material and a battery cell including the same.

[0005] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power or renewable energy.

[0006] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to produce a positive electrode and a negative electrode, and these are stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is housed in an outer casing, and after injecting an electrolyte, it is sealed.

[0007] Battery cells are classified into pouch type and can type depending on the material of the outer casing that houses the electrode assembly. The pouch type houses the electrode assembly in an outer casing made of a flexible polymer material. The can type, on the other hand, houses the electrode assembly in an outer casing made of materials such as metal or plastic.

[0008] Generally, a pouch-type outer material is manufactured by performing press processing on a flexible pouch film to form a cup-shaped storage portion. Then, once the storage portion is formed, an electrode assembly is housed inside the storage portion and the terrace portion is sealed to manufacture a battery cell.

[0009] The pouch-type outer material is formed to match the thickness of the electrode assembly while considering insertability. However, a sliding phenomenon may occur where the height of the electrode active material becomes uneven and lowers at the ends. As a result, a slight difference in thickness occurs between the center and the edges of the electrode assembly.

[0010] Conventionally, the storage portion of the pouch-type outer material was formed to a uniform depth without considering these thickness differences, so empty spaces were created within the storage portion, and there was a possibility of safety issues such as lithium deposition or electrode displacement.

[0011] One problem that the present invention aims to solve is to provide an outer material that appropriately compensates for a thickness difference of an electrode assembly and a battery cell including the same.

[0012] A battery cell according to an embodiment of the present invention may include an electrode assembly in which a positive electrode and a negative electrode are alternately interposed with a separator between them; and a pouch-type outer material having a storage portion formed by recessing to accommodate the electrode assembly. The storage portion may include a center region; and a pair of end regions located on both sides of the center region, having a depth dimension smaller than that of the center region, and being asymmetric to each other.

[0013] The above pair of end regions may be located inside the punch edge connecting both sides and the bottom surface of the storage portion.

[0014] The above pair of end regions may have a depth dimension that decreases as they extend outward.

[0015] The above pair of end regions may overlap with the sliding portion of the anode in the thickness direction of the electrode assembly.

[0016] The electrode assembly may be provided with an anode tab protruding from one side of the electrode assembly and electrically connected to the anode; and a cathode tab protruding from the other side of the electrode assembly and electrically connected to the cathode. The pair of end regions may include a first end region located on one side of the center region where the anode tab protrudes; and a second end region located on the other side of the center region where the cathode tab protrudes.

[0017] The widths of the first end area and the second end area can correspond to each other.

[0018] The depth dimension of a first point located within the first end area and forming a first distance from one side of the storage portion may be greater than the depth dimension of a second point located within the second area and forming the first distance from the other side of the storage portion.

[0019] Within the first end area, based on one side of the storage portion, the depth dimension of a third point located at a second distance smaller than the first distance may be smaller than the depth dimension of the first point and greater than or equal to the depth dimension of the second point.

[0020] At one side where the positive electrode tab of the electrode assembly protrudes, the end of the negative electrode protrudes by a first length relative to the end of the positive electrode, and at the other side where the negative electrode tab of the electrode assembly protrudes, the end of the negative electrode may protrude by a second length longer than the first length relative to the end of the positive electrode.

[0021] The first length above corresponds to the second distance, and the second length can correspond to the first distance.

[0022] The first end area may have a step formed such that the height decreases at the third point, and the second end area may have a step formed such that the height decreases at the second point.

[0023] An exterior material according to an embodiment of the present invention may be a pouch-type exterior material having a storage portion that is recessed. The storage portion may include a center region; and a pair of end regions located on both sides of the center region, having a depth dimension smaller than the depth dimension of the center region, and being asymmetric to each other.

[0024] According to a preferred embodiment of the present invention, the empty space within the receiving portion caused by the difference in thickness between the central portion and the edge portion of the electrode assembly can be minimized, and problems such as lithium precipitation or electrode displacement that may occur in the electrode assembly due to the empty space can be resolved.

[0025] In addition to this, the configurations according to the preferred embodiments of the present invention may include effects that are easily predictable by those skilled in the art.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0027] FIG. 1 is an exploded perspective view of a battery cell according to one embodiment of the present invention.

[0028] Figure 2 is a front view of the electrode assembly shown in Figure 1.

[0029] Figure 3 is an enlarged view of a portion of the one anode shown in Figure 2.

[0030] Figure 4 is a graph showing the thickness profile of the electrode and the thickness profile of the electrode assembly for an electrode assembly according to a manufacturing example.

[0031] FIG. 5 is a cross-sectional view of an exterior material according to one embodiment of the present invention.

[0032] FIG. 6 is a cross-sectional view of an exterior material according to another embodiment of the present invention.

[0033] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0034] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0035] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0036] Each component of a secondary battery according to one embodiment of the present invention is schematically illustrated in the drawing, and the size or thickness of the lines of the components may be expressed somewhat exaggerated for ease of understanding.

[0037] FIG. 1 is an exploded perspective view of a battery cell according to one embodiment of the present invention, FIG. 2 is a front view of an electrode assembly shown in FIG. 1, and FIG. 3 is an enlarged view of a part of a positive electrode shown in FIG. 2.

[0038] A battery cell (100) according to an embodiment of the present invention may include an electrode assembly (110) and an outer casing (120).

[0039] The electrode assembly (110) may alternately have an anode (210) and a cathode (220) interposed with a separator (230) in between. That is, the electrode assembly (110) may include an anode (210), a cathode (220), and a separator (230) interposed between the anode (210) and the cathode (220). The electrode assembly (110) may be accommodated in an outer casing (120), more specifically in a storage portion (121) to be described later.

[0040] A plurality of positive electrodes (210), negative electrodes (220), and separators (230) may each be provided. However, this is not limited thereto and may vary depending on the type of electrode assembly (110). The types of electrode assemblies (110) include stack type, jelly roll type, stack and folding type, etc., and the type of electrode assembly (110) is not limited.

[0041] The electrode assembly (110) may be provided with a positive lead (112A) and a negative lead (112B). The positive lead (112A) may be electrically connected to the positive electrode (210), and the negative lead (112B) may be electrically connected to the negative electrode (220). The positive lead (112A) may protrude to one side of the outer casing (120), and the negative lead (112B) may protrude to the other side of the outer casing (120). That is, the positive lead (112A) and the negative lead (112B) may protrude in opposite directions.

[0042] More specifically, the positive lead (112A) can be connected to the positive tab (111A) of the electrode assembly (110), and the negative lead (112B) can be connected to the negative tab (111B) of the electrode assembly (110). Each positive tab (111A) can be connected to each positive (210), and each negative tab (111B) can be connected to each negative (220). Multiple positive tabs (111A) can be gathered together to form a positive tab joint, and the positive lead (112A) can be connected to the positive tab joint by welding or the like. Similarly, multiple negative tabs (111B) can be gathered together to form a negative tab joint, and the negative lead (112B) can be connected to the negative tab joint by welding or the like.

[0043] The positive electrode tab (111A) and the negative electrode tab (111B) can serve as a path through which electrons can move between the inside and outside of the electrode assembly (110). The positive electrode tab (111A) may protrude from one side of the electrode assembly (110), and the negative electrode tab (111B) may protrude from the other side of the electrode assembly (110).

[0044] The positive lead (112A) has an inner end connected to the positive tab (111A) and an outer end that may protrude to the outside of one side of the outer casing (120). The negative lead (112B) has an inner end connected to the negative tab (111B) and an outer end that may protrude to the outside of the other side of the outer casing (120).

[0045] Meanwhile, the outer material (120) may be formed by molding a laminate sheet and may accommodate an electrode assembly (110) inside. That is, the outer material (120) may be a pouch-type outer material.

[0046] The exterior material (120) may include a first exterior material (120A) having a storage portion (121) formed therein for accommodating an electrode assembly (110), a second exterior material (120B) covering the storage portion (121), and sealing portions (122, 123) in which the first exterior material (120A) and the second exterior material (120B) come into contact with each other and are sealed.

[0047] As illustrated in FIG. 1, the first exterior material (120A) and the second exterior material (120B) can be connected by a folding portion (124). In this case, the first exterior material (120A) and the second exterior material (120B) can be sealed by having the remaining three sides, excluding the side where the folding portion (124) is formed, come into contact with each other.

[0048] However, it is not limited to this, and the first exterior material (120A) and the second exterior material (120B) may be manufactured separately from each other. In this case, the first exterior material (120A) and the second exterior material (120B) may be sealed by having four sides in contact with each other.

[0049] In the first exterior material (120A), a storage portion (121) may be formed by recessing it to a predetermined depth. The depth of the storage portion (121) may refer to the depth of recessing for the sealing portions (122, 123). The second exterior material (120B) may cover this storage portion (121). The second exterior material (120B) may be formed flat.

[0050] However, this is not limited thereto, and a storage portion (121) may also be formed in the second outer material (120B). In this case, the storage portion (121) of the second outer material (120B) may cover the storage portion (121) of the first outer material (120A). That is, both storage portions (121) may form a single receiving space in which the electrode assembly (110) is received.

[0051] The sealing portion (122, 123) may include a first sealing portion (122) in which electrode leads (112A, 112B) protrude, and a second sealing portion (123) extending in a direction different from the extension direction of the first sealing portion (122). The first sealing portion (122) may be a short-sided sealing portion, and the second sealing portion (123) may be a long-sided sealing portion.

[0052] The first sealing portion (122) may be located on a part of the perimeter of the storage portion (121). For example, the first sealing portion (122) may be located on both sides in the full length direction of the storage portion (121) and may extend in the full width direction. The electrode leads (112A, 112B) may protrude to the outside of the exterior material (120) through the first sealing portion (122).

[0053] The second sealing portion (123) may be located on a different part of the circumference of the storage portion (121). For example, the second sealing portion (123) may be located on one side in the full width direction of the storage portion (121) and may extend in the full length direction. The second sealing portion (123) may connect both first sealing portions (122). The second sealing portion (123) may be located on the opposite side of the folding portion (124). The second sealing portion (123) may be a part where the electrode leads (112A, 112B) are not protruding.

[0054] Meanwhile, referring to FIG. 2, the negative electrode (220) generally has a larger size than the positive electrode (210). That is, the end of the negative electrode (220) may protrude outwardly more than the end of the positive electrode (210).

[0055] Additionally, considering the protrusion direction of each electrode tab (111A, 111B), the length at which the end of the negative electrode (220) protrudes more than the end of the positive electrode (210) may differ from each other on both sides of the electrode assembly (110).

[0056] More specifically, on one side (left side in FIG. 2) where the positive lead (112A) of the electrode assembly (110) protrudes, the end of the negative electrode (220) may protrude by a first length (L1) relative to the end of the positive electrode (210). On the other side (right side in FIG. 2) where the negative lead (112B) of the electrode assembly (110) protrudes, the end of the negative electrode (220) may protrude by a second length (L2) relative to the end of the positive electrode (210). Here, the second length (L2) may be longer than the first length (L1). That is, the end of the negative electrode (220) may protrude further from the side where the negative lead (112B) protrudes.

[0057] Referring to FIG. 3, each electrode (210, 220) may include a current collector (211, 221) and an active material layer (212, 222) coated on the current collector (211, 221). The composition of materials mainly used for the positive current collector (211), the positive active material layer (212), the negative current collector (221), and the negative active material layer (222) is a well-known technology, so a description is omitted.

[0058] During the coating process of the active material layer (212, 222), a sliding portion (212a, 222a) in which the coating thickness decreases may occur at the end of the active material layer (212, 222). As a result, the thickness of the electrode (210, 220) may decrease towards the end.

[0059] In particular, regarding the electrode assembly (110), the point where the sliding portion (212a) of the positive active material layer (212) begins may be located further inside than the point where the sliding portion (222a) of the negative active material layer (222) begins. This is because, as previously explained, the negative electrode (220) has a larger size than the positive electrode (210). Therefore, the reduction in thickness of the electrode assembly (110) may occur starting from the point where the sliding portion (212a) of the positive active material layer (212) begins. Considering this, when designing the end regions (1212, 1213) (see FIG. 4) of the outer material (120) to be described later, the design may take into account the reduction in thickness of the positive electrode (210) rather than the negative electrode (220).

[0060] Figure 4 is a graph showing the thickness profile of the electrode and the thickness profile of the electrode assembly for an electrode assembly according to a manufacturing example.

[0061] According to the manufacturing example, on one side (left) where the positive electrode tab (111A) of the electrode assembly (110) protrudes, the end of the negative electrode (220) protrudes 2.3 mm further than the end of the positive electrode (210). Also, on the other side (right) where the negative electrode tab (111B) of the electrode assembly (110) protrudes, the end of the negative electrode (220) protrudes 3.1 mm further than the end of the positive electrode (210). That is, the first length (L1) is measured as 2.3 mm, and the second length (L2) is measured as 3.1 mm. As previously explained, it can be confirmed that the second length (L2) is longer than the first length (L1).

[0062] FIG. 4(a) shows the thickness profiles of the anode (210) and the cathode (220). Here, the horizontal axis represents the position along the longitudinal direction of the electrode assembly (110), and the vertical axis represents the thickness (mm) of the electrodes (210, 220) at each position.

[0063] Referring to FIG. 4(a), the thickness of the anode (210) gradually decreases toward both ends of the electrode assembly (110) and then decreases sharply at the end of the anode (210). Likewise, the thickness of the cathode (220) gradually decreases toward both ends of the electrode assembly (110) and then decreases sharply at the end of the cathode (220). Here, the portion where the thickness of each electrode (210, 220) gradually decreases may be the portion where the sliding portion (212a, 222a) is formed smoothly.

[0064] Additionally, referring to FIG. 4(a), it can be seen that the thickness reduction rate of the anode (210) is greater than the thickness reduction rate of the cathode (220). That is, as one moves toward both ends of the electrode assembly (110), the difference between the thickness of the anode (210) and the thickness of the cathode (220) widens. Therefore, the thickness change rate of the electrode assembly (110) can be determined mainly by the thickness change rate of the anode (210).

[0065] Accordingly, FIG. 4(b) shows the thickness profile of the electrode assembly (110) within the range where the anode (210) is located. Here, the horizontal axis represents the position along the longitudinal direction of the electrode assembly (110), and the vertical axis represents the thickness ratio of the electrode assembly (110) at each position relative to the thickness of the central part of the electrode assembly (110).

[0066] Referring to FIG. 4(b), the thickness of the electrode assembly (110) decreases as it moves toward both ends, and the rate of thickness reduction at both ends may differ. In particular, it can be seen that the rate of thickness reduction of the electrode assembly (110) is greater as it moves toward the other side (right) where the negative tab (111B) protrudes than on the one side (left) where the positive tab (111A) protrudes.

[0067] In this regard, as previously explained, the distance between the ends of the cathode (220) and the anode (210) is greater on the side where the cathode tab (111B) protrudes (right side) than on the side where the anode tab (111A) protrudes (left side) (L2 > L1). In other words, the anode (210) is relatively offset toward the side where the anode tab (111A) protrudes. Therefore, because the anode (210), which has a greater influence on the thickness change of the electrode assembly (110), is offset toward one side, the rate of thickness reduction of the electrode assembly (110) may be greater as it moves toward the other side (right side) where the cathode tab (111B) protrudes, compared to the side (left side) where the anode tab (111A) protrudes.

[0068] However, the effect of such deviation of the anode (210) on the thickness of the electrode assembly (110) increases as it approaches the ends of the electrode assembly (110), and the effect may become negligible as it approaches the center of the electrode assembly (110). Therefore, the point at which the thickness of the electrode assembly (110) begins to decrease may be the same or similar on both sides. In fact, in the present manufacturing example, the thickness began to decrease from both points 20 mm from both ends of the electrode assembly (110).

[0069] FIG. 5 is a cross-sectional view of an exterior material according to one embodiment of the present invention.

[0070] The outer material (120) according to an embodiment of the present invention can be designed by taking into account the thickness profile of the electrode assembly (110) described above.

[0071] The storage portion (121) of the exterior material (120) may include a center area (1211) and a pair of end areas (1212, 1213). More specifically, the bottom surface of the storage portion (121) may include a center area (1211) and a pair of end areas (1212, 1213).

[0072] The center area (1211) may have a roughly constant depth dimension (d0).

[0073] A pair of end regions (1212, 1213) may be located on both sides of the center region (1211). More specifically, a pair of end regions (1212, 1213) may be located on both sides of the center region (1211) with respect to the longitudinal direction of the storage portion (121).

[0074] A pair of end regions (1212, 1213) may be located inside the punch edge connecting both sides and the bottom surface of the storage portion (121).

[0075] The depth dimension of each end region (1212, 1213) may be smaller than the depth dimension (d0) of the center region (1211). Thus, the difference in thickness between the central and edge portions of the electrode assembly (110) described above can be compensated. Compensation means minimizing the empty space within the receiving portion (121). By doing so, problems such as lithium deposition or electrode displacement that may occur in the electrode assembly (110) due to the empty space can be resolved.

[0076] A pair of end regions (1212, 1213) may be asymmetric to each other. More specifically, with respect to the longitudinal direction of the storage portion (121), the depth profiles of the pair of end regions (1212, 1213) may differ from each other. Thus, it is possible to compensate for the different thickness reduction rates at both ends of the electrode assembly (110) described above.

[0077] Each end region (1212, 1213) may have a depth dimension that decreases toward the outside. Thus, it is possible to compensate for the decrease in thickness of the electrode assembly (110) described above toward both ends.

[0078] As previously explained, the rate of change in thickness of the electrode assembly (110) can be determined primarily by the rate of change in thickness of the sliding portion (212a) of the anode (210) (see FIG. 3). Accordingly, each end region (1212, 1213) can overlap with the sliding portion (212a) of the anode (210) in the thickness direction of the electrode assembly (110). This allows for compensation for the reduction in thickness of the sliding portion (212a) of the anode (210).

[0079] More specifically, a pair of end regions (1212, 1213) may include a first end region (1212) and a second end region (1213). The first end region (1212) may be located on one side of the center region (1211) where the positive lead (112A) (see FIG. 2) protrudes. The second end region (1213) may be located on the other side of the center region (1211) where the negative lead (112B) protrudes.

[0080] The boundary (b1) between the center area (1211) and the first end area (1212) may be a point where the depth of the storage area (121) begins to decrease as it approaches one side of the storage area (121) in the longitudinal direction of the storage area (121). The boundary (b2) between the center area (1211) and the second end area (1213) may be a point where the depth of the storage area (121) begins to decrease as it approaches the other side of the storage area (121) in the longitudinal direction of the storage area (121).

[0081] As previously explained, the point where the thickness of the electrode assembly (110) begins to decrease may be the same or similar on both sides. Accordingly, the widths of the first end region (1212) and the second end region (1213) may correspond to each other. More specifically, with respect to the longitudinal direction of the storage portion (121), the width (w1) of the first end region (1212) may correspond to the width (w2) of the second end region (1213). Here, "corresponds" may mean that they are the same or similar.

[0082] Meanwhile, a first point (P1) can be defined that is located within the first end area (1212) and forms a first distance (g1) from one side of the storage unit (121). Similarly, a second point (P2) can be defined that is located within the second end area (1213) and forms the first distance (g1) from the other side of the storage unit (121). In this case, the depth dimension (d11) of the first point (P1) may be greater than the depth dimension (d21) of the second point (P2).

[0083] That is, based on each point located at an equal distance from both sides of the storage section (121), the depth dimension of the second end area (1213) may be smaller than the depth dimension of the first end area (1212). In other words, as one approaches both sides of the storage section (121), the depth dimension of the second end area (1213) may decrease more rapidly than the depth dimension of the first end area (1212). This may mean that, with respect to the length direction of the storage section (121), the rate of depth reduction of the second end area (1213) is greater than the rate of depth reduction of the first end area (1212).

[0084] As previously explained, the thickness reduction rate of the electrode assembly (110) may be greater as it moves toward the other side (right) where the negative lead (112B) protrudes, compared to the one side (left) where the positive lead (112A) protrudes. Accordingly, the depth reduction rate of the second end region (1213) is formed to be greater than the depth reduction rate of the first end region (1212), thereby appropriately compensating for the different thickness reduction rates of both ends of the electrode assembly (110).

[0085] Meanwhile, a third point (P3) can be defined that is located within the first end area (1212) and forms a second distance (g2) smaller than the first distance (g1) from one side of the storage portion (121). In this case, the depth dimension (d12) of the third point (P3) may be smaller than the depth dimension (d11) of the first point (P1) and greater than or equal to the depth dimension (d21) of the second point (P2).

[0086] That is, as it approaches one side of the storage portion (121), the depth of the first end region (1212) can decrease more slowly. This may mean that the rate of depth reduction of the first end region (1212) is even smaller. In this way, the different thickness reduction rates of the two ends of the electrode assembly (110) can be more appropriately compensated.

[0087] In this regard, for the exterior material according to the manufacturing example, the depth dimension (d0) of the center area (1211) is 5.76 mm, the first distance (g1) is 3 mm, the second distance (g2) is 2 mm, the depth dimension (d21) of the second point (P2) is 5.07 mm, and the depth dimension (d12) of the third point (P3) is 5.3 mm. The depth dimension (d11) of the first point (P1) was not directly measured, but it was formed to be larger than the depth dimension (d12) of the third point (P3), which is 5.3 mm.

[0088] In addition, the second distance (g2) corresponds to the first length (L1) described above (see FIG. 4), and the first distance (g1) may correspond to the second length (L2) described above (see FIG. 4). By doing so, the reduction rate of thickness of the electrode assembly (110) due to the deviation of the anode (210) described above can be appropriately compensated.

[0089] FIG. 6 is a cross-sectional view of an exterior material according to another embodiment of the present invention.

[0090] Below, content that overlaps with the previously explained material will be referenced, and the differences will be explained in detail.

[0091] In the case of an exterior material (120) according to another embodiment of the present invention, a step may be formed in the first end area (1212) such that the height decreases at the third point (P3). Additionally, a step may be formed in the second end area (1213) such that the height decreases at the second point (P2).

[0092] More specifically, as one side of the storage portion (121) approaches, the depth of the first end area (1212) may decrease discontinuously at the third point (P3). Additionally, as one side of the storage portion (121) approaches, the depth of the second end area (1212) may decrease discontinuously at the second point (P2).

[0093] As previously explained, the distance (g2) between one side of the storage portion (121) and the third point (P3) may correspond to the length (L1) where the negative electrode (220) protrudes more than the positive electrode (210) on one side of the electrode assembly (110). Additionally, the distance (g1) between the other side of the storage portion (121) and the second point (P2) may correspond to the length (L2) where the negative electrode (220) protrudes more than the positive electrode (210) on the other side of the electrode assembly (110).

[0094] That is, the area between one side of the storage portion (121) and the third point (P3) in the first end area (1212), and the edge portion of the negative electrode (220) protruding more than the positive electrode (210) on one side of the electrode assembly (110), can be overlapped in the thickness direction of the electrode assembly (110). Likewise, the area between the other side of the storage portion (121) and the second point (P2) in the second end area (1213), and the edge portion of the negative electrode (220) protruding more than the positive electrode (210) on the other side of the electrode assembly (110), can be overlapped in the thickness direction of the electrode assembly (110).

[0095] Accordingly, by forming a step difference such that the height is reduced at the third point (P3) of the first end region (1212) and the second point (P2) of the second end region (1213), the reduction in thickness of the electrode assembly (200) due to the size difference between the anode (210) and the cathode (220) can be effectively compensated.

[0096] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0097] Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments.

[0098] The scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

[0099] [Explanation of the symbol]

[0100] 100: Battery cell 110: Electrode assembly

[0101] 111A; Anode tab 111B; Cathode tab

[0102] 112A; Anode Lead 112B; Cathode Lead

[0103] 120: Exterior material 121: Storage compartment

[0104] 122: 1st sealing part 123: 2nd sealing part

[0105] 1211: Center Area 1212: 1st End Area

[0106] 1213: Second End Area 210: Positive

[0107] 220: Cathode 230: Separator

Claims

1. An electrode assembly in which an anode and a cathode are alternately interposed with a separator in between; and It includes a pouch-type outer material having a storage portion that is recessed to accommodate the electrode assembly, and The above storage unit is, Center area; and A battery cell comprising a pair of end regions located on both sides of the center region, having a depth dimension smaller than the depth dimension of the center region, and being asymmetric to each other.

2. In Paragraph 1, The above pair of end regions is a battery cell located inside the punch edge connecting both sides and the bottom surface of the storage portion.

3. In Paragraph 1, The above pair of end regions is a battery cell in which the depth dimension decreases toward the outside.

4. In Paragraph 1, The above pair of end regions is a battery cell that overlaps with the sliding portion of the positive electrode in the thickness direction of the electrode assembly.

5. In Paragraph 1, The above electrode assembly includes, An anode tab protruding from one side of the electrode assembly and electrically connected to the anode; and A cathode tab is provided that protrudes from the other side of the electrode assembly and is electrically connected to the cathode, and The above pair of end regions is, A first end region located on one side of the two sides of the center region where the positive tab protrudes; and A battery cell comprising a second end region located on the other side of the two sides of the center region where the negative electrode tab protrudes.

6. In Paragraph 5, The widths of the first end region and the second end region correspond to each other in the battery cell.

7. In Paragraph 5, A battery cell in which the depth dimension of a first point located within the first end area and forming a first distance from one side of the storage portion is greater than the depth dimension of a second point located within the second area and forming the first distance from the other side of the storage portion.

8. In Paragraph 7, A battery cell in which, based on one side of the storage portion within the first end area, the depth dimension of a third point located at a second distance smaller than the first distance is smaller than the depth dimension of the first point and greater than or equal to the depth dimension of the second point.

9. In Paragraph 8, At one side where the positive electrode tab of the electrode assembly protrudes, the end of the negative electrode protrudes by a first length relative to the end of the positive electrode, and A battery cell in which, on the other side where the negative electrode tab of the electrode assembly protrudes, the end of the negative electrode protrudes by a second length longer than the first length relative to the end of the positive electrode.

10. In Paragraph 9, The above first length corresponds to the above second distance, and The above second length is a battery cell corresponding to the above first distance.

11. In Paragraph 8, The first end area above has a step formed such that the height decreases at the third point, and The above second end region is a battery cell in which a step is formed so that the height decreases at the above second point.

12. In a pouch-type exterior material having a recessed storage portion, The above storage unit is, Center area; and An exterior material comprising a pair of end regions located on both sides of the center region, having a depth dimension smaller than the depth dimension of the center region, and being asymmetric to each other.

Images