Rechargeable battery

Abstract

A rechargeable battery includes an electrode assembly and a case configured to accommodate and seal the electrode assembly, in which the electrode assembly includes: a cell stack including a plurality of first electrode plates and a plurality of second electrode plates alternately stacked one by one with a separator interposed therebetween, the cell stack includes a first portion having a first thickness and a second portion having a second thickness smaller than the first thickness; a correction sheet on the second portion and configured to homogenize a thickness of the cell stack; and a pair of first fixing portions on a portion of the front surface, the side surface, and the rear surface of the cell stack and having a portion overlapping the correction sheet.

Description

Technical Field

[0001] Embodiments relate to a rechargeable battery, and more particularly, to a structure of a stacked electrode assembly. Background Art

[0002] Rechargeable batteries that can be charged are used for various purposes, such as power sources for small electronic devices such as mobile phones and notebook computers, and power sources for driving motors of transportation vehicles such as electric vehicles and hybrid vehicles. A rechargeable battery basically includes an electrode assembly and a housing for accommodating and sealing the electrode assembly. According to the external shape of the rechargeable battery, the rechargeable battery can be classified into a cylindrical battery, a angular battery, a pouch battery, etc.

[0003] The electrode assembly can be configured by alternately stacking a plurality of positive electrode plates and a plurality of negative electrode plates one by one with a separator therebetween. The positive electrode plate and the negative electrode plate can each include a substrate and a composite material layer located on two opposing surfaces of the substrate. Uneven thickness may occur during the process of manufacturing the composite material layer. The uneven thickness of the composite material layer causes an uneven thickness of the electrode assembly. In addition, in an area where the thickness of the composite material layer of the electrode assembly is insufficient, the connection force between the positive electrode plate, the separator and the negative electrode plate is reduced, which may reduce the output characteristics and output stability of the rechargeable battery. Summary of the invention

[0004] Embodiments include a rechargeable battery. The rechargeable battery includes an electrode assembly and a housing configured to accommodate and seal the electrode assembly, wherein the electrode assembly includes a single stack, the single stack includes a plurality of first electrode plates and a plurality of second electrode plates alternately stacked one by one with a separator interposed therebetween, the single stack includes a first portion having a first thickness and a second portion having a second thickness less than the first thickness. A correction sheet is located on the second portion and makes the thickness of the single stack uniform. A pair of first fixing portions are located on a portion of the front surface, the side surface, and the rear surface of the single stack, and the pair of first fixing portions have a portion overlapping the correction sheet.

[0005] The correction sheet may include a pair of correction sheets respectively located on the front and rear surfaces of the second portion.

[0006] Each of the pair of correction sheets may be configured as a polymer film having an adhesive layer.

[0007] The single body stack may have a uniform thickness by being pressed by a heat press device after the correction sheet is attached to the second portion.

[0008] The single body stack may include a first edge and a second edge and a third edge intersecting the first edge, wherein at the first edge, a plurality of first terminal tabs may extend from the plurality of first electrode plates and a plurality of second terminal tabs may extend from the plurality of second electrode plates, and the second portion and the correction sheet may be positioned adjacent to the first edge.

[0009] The second portion and the correction sheet may each have a width equal to a width of the single stack.

[0010] The pair of first fixing portions may be located on a portion of the front surface, the side surface, and the rear surface of the monomer stack at the second edge and the third edge, and may overlap with the correction sheet on at least one of the front surface and the rear surface of the monomer stack.

[0011] The cell stack may include a fourth edge parallel to the first edge and intersecting the second edge and the third edge, and the electrode assembly may further include a second fixing portion located at the fourth edge on a portion of the front surface, the side surface, and the rear surface of the cell stack.

[0012] The electrode assembly may further include a third fixing portion, which is located between the plurality of first terminal tabs and the plurality of second terminal tabs at the first edge, and the third fixing portion may be located on a portion of the front surface, the side surface, and the rear surface of the single body stack at the first edge, and the third fixing portion includes a portion overlapping with the correction sheet.

[0013] The electrode assembly may further include a fourth fixing portion configured to surround the plurality of first tabs and the plurality of second tabs.

[0014] Embodiments include a rechargeable battery. The rechargeable battery includes an electrode assembly and a housing configured to accommodate and seal the electrode assembly. The electrode assembly includes: a single-cell stack, including a separator folded multiple times in a zigzag pattern, and a plurality of first electrode plates and a plurality of second electrode plates alternately stacked one by one with the separator interposed therebetween, the single-cell stack being divided into a first portion and a second portion, the second portion having a thickness less than that of the first portion. A pair of correction sheets are provided on the second portion and are located on the front and rear surfaces of the single-cell stack to uniformize the thickness of the single-cell stack, and a plurality of fixing portions are attached to the edges of the single-cell stack and on the front, side and rear surfaces of the single-cell stack, the plurality of fixing portions having portions overlapping with the pair of correction sheets while covering the pair of correction sheets from the outside.

[0015] The single body stack may include a first edge and a second edge and a third edge intersecting the first edge, wherein at the first edge, a plurality of first terminal tabs may extend from the plurality of first electrode plates and a plurality of second terminal tabs may extend from the plurality of second electrode plates, and the second portion and the pair of correction tabs may be positioned adjacent to the first edge.

[0016] The plurality of fixing portions may include a pair of first fixing portions, and the pair of first fixing portions may be attached to the pair of correction sheets and the single body stack at the second edge and the third edge.

[0017] The plurality of fixing portions may further include a third fixing portion, and the third fixing portion may be provided between the plurality of first tabs and the plurality of second tabs at the first edge and attached to the pair of correction tabs and the cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0019] Figure 1 is an exploded perspective view of a rechargeable battery according to one or more embodiments;

[0020] Figure 2 According to one or more embodiments, Figure 1 A cross-sectional view of the electrode assembly taken along line AA in FIG.

[0021] Figure 3 is an example of a method according to one or more embodiments Figure 2 A top plan view of the electrode assembly illustrated in FIG. 1 in an unfolded state;

[0022] Figure 4 According to one or more embodiments Figure 3 A partially enlarged cross-sectional view of the first electrode plate and the second electrode plate illustrated in FIG.

[0023] Figure 5 According to one or more embodiments, Figure 1 A cross-sectional view of the electrode assembly taken along line BB in FIG.

[0024] Figure 6 is an example of a heat pressing device and Figure 5 A schematic diagram of a monomer stack illustrated in FIG.

[0025] Figure 7 is an example based on (with Figure 6 Schematic diagram of a heat pressing device and a monomer stack of a comparative example;

[0026] Figure 8 is a perspective view of an electrode assembly of a rechargeable battery according to one or more embodiments;

[0027] Fig. 9 According to one or more embodiments, Figure 8 A cross-sectional view of the electrode assembly taken along line CC in FIG.

[0028] Fig.10 According to one or more embodiments, Figure 8 A cross-sectional view of the electrode assembly taken along line DD in FIG. 1 ; and

[0029] Fig.11 is a schematic diagram illustrating electrode assemblies according to Examples 1 to 4 and a comparative example. DETAILED DESCRIPTION

[0030] In the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or element, it can be directly on the other layer or element, or there may be intervening layers. Furthermore, it will be understood that when a layer is referred to as being "under" another layer, it can be directly under the other layer, and there may also be one or more intervening layers. In addition, it will be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may also be one or more intervening layers. The same reference numerals refer to the same elements throughout.

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments. The present disclosure can be implemented in various ways and is not limited to the embodiments described herein.

[0032] Figure 1is an exploded perspective view of a rechargeable battery according to one or more embodiments, Figure 2 According to one or more embodiments, Figure 1 A cross-sectional view of the electrode assembly taken along line AA in FIG.

[0033] refer to Figure 1 and Figure 2 , a rechargeable battery 100 according to one or more embodiments may include an electrode assembly 120 and a case 130 configured to accommodate and seal the electrode assembly 120 and an electrolyte. Figure 1 A pouch-type case 130 is illustrated. However, the type of the case is not limited to the illustrated example and may vary.

[0034] The housing 130 may include a lower housing 131 and a flat upper housing 135, the lower housing 131 including a receiving portion 132 and a sealing portion 133. The lower housing 131 and the upper housing 135 may be integrally connected to each other. The receiving portion 132 may be a concave space provided to receive the electrode assembly 120. The sealing portion 133 may be positioned around the receiving portion 132.

[0035] After the electrode assembly 120 is accommodated in the accommodation portion 132, the upper case 135 may be folded and may overlap the lower case 131 and the electrode assembly 120. In addition, the edge of the sealing portion 133 and the edge of the upper case 135 may be integrally connected by thermal bonding so that the electrode assembly 120 may be sealed.

[0036] The housing 130 may include a metal sheet and a plurality of polymer sheets configured to cover the inner and outer surfaces of the metal sheet. The metal sheet may be an aluminum sheet and may provide mechanical strength to the housing 130. The polymer sheet may be any one of a polyethylene terephthalate (PET) sheet, a nylon sheet, and a PET-nylon composite sheet and is used to insulate and protect the housing 130.

[0037] The electrode assembly 120 may include a unit stack 40. The unit stack 40 may include a plurality of first electrode plates 10 and a plurality of second electrode plates 20 alternately stacked one by one with the separator 30 interposed therebetween. The unit stack 40 may include a plurality of separators or a single separator. Figure 2 A single separator 30 is illustrated as an example. The separator 30 may have a long strip shape and be folded multiple times in a zigzag pattern.

[0038] Figure 3 is an example of a method according to one or more embodiments Figure 2 A top plan view of an electrode assembly in an unfolded state, Figure 4 According to one or more embodiments Figure 3 A partially enlarged cross-sectional view of the first electrode plate and the second electrode plate illustrated in FIG.

[0039] refer to Figure 2 to Figure 4 The diaphragm 30 may include a plurality of flat portions 31 and a plurality of bent portions 32, 33. The flat portions 31 and the bent portions 32, 33 may be alternately located one by one in the longitudinal direction ( Figure 3 The bent portions 32, 33 may include a first bent portion 32 located on one side (right side) of the flat portion 31, and a second bent portion 33 located on the other side (left side) of the flat portion 31. The first bent portion 32 and the second bent portion 33 may be alternately located one by one in the longitudinal direction (direction L) of the diaphragm 30.

[0040] The first electrode plate 10 and the second electrode plate 20 may be located between two adjacent flat portions 31 among the plurality of flat portions 31. In the unfolded state of the separator 30, the first electrode plate 10 and the second electrode plate 20 may be positioned adjacent to different surfaces of the separator 30. For example, when the first electrode plate 10 is positioned adjacent to one surface (e.g., the front surface) of the separator 30, the second electrode plate 20 may be positioned adjacent to the opposite surface (e.g., the rear surface) of the separator 30.

[0041] The first electrode plate 10 may include a first substrate 11, a first composite material layer 12 located on two opposite surfaces of the first substrate 11, and a first tab 13 extending from the first substrate 11 toward one side (e.g., upward). At the upper edge of the monomer stack 40, a plurality of first tabs 13 may extend from the plurality of first electrode plates 10. The first composite material layer 12 may not be located on the first tab 13. The second electrode plate 20 may include a second substrate 21, a second composite material layer 22 located on two opposite surfaces of the second substrate, and a second tab 23 extending from the second substrate 21 toward one side (e.g., upward). At the upper edge of the monomer stack 40, a plurality of second tabs 23 may extend from the plurality of second electrode plates 20. The second composite material layer 22 may not be located on the second tab 23.

[0042] The first substrate 11 may be configured as a copper foil or a nickel foil. The first composite material layer 12 may include graphite, a conductive material, a binder, etc. The second substrate 21 may be configured as an aluminum foil. The second composite material layer 22 may include a transition metal oxide such as LiCoO2, LiNiO2 or LiMn2O4, a conductive material, a binder, etc. The first electrode plate 10 may be referred to as a negative electrode plate, and the second electrode plate 20 may be referred to as a positive electrode plate.

[0043] The separator 30 may include a polymer material such as polyethylene (PE) or polypropylene (PP), and may insulate the first and second electrode plates 10 and 20 while allowing lithium ions to move.

[0044] When the rechargeable battery 100 is charged, lithium ions are introduced into the first composite material layer 12, and the first composite material layer 12 expands. When the rechargeable battery 100 is discharged, lithium ions are discharged from the first composite material layer 12, and the first composite material layer 12 shrinks. As the service life of the rechargeable battery 100 increases, the first composite material layer 12 may deteriorate due to repeated changes in volume. Therefore, in consideration of degradation, the first electrode plate 10 may be configured to be larger than the second electrode plate 20.

[0045] For example, based on Figure 3 The width direction of the diaphragm 30 ( Figure 3 The first substrate 11 may have a height greater than that of the second substrate 21, and the first substrate 11 and the second substrate 22 may have a height difference of h. Therefore, the first electrode plate 10 may include a portion that does not overlap with the adjacent second electrode plate 20.

[0046] The plurality of first electrode plates 10 can be manufactured by forming the first composite material layer 12 on two opposite surfaces of a first substrate having a long strip shape by strip coating, and then cutting the first substrate into unit substrates. In addition, the plurality of second electrode plates 20 can be manufactured by forming the second composite material layer 22 on two opposite surfaces of a second substrate having a long strip shape by strip coating, and then cutting the second substrate into unit substrates.

[0047] When the first composite material layer 12 and the second composite material layer 22 are formed by strip coating, uneven thickness may occur. For example, in the upper region of the first substrate 11 adjacent to the first terminal tab 13, the thickness of the first composite material layer 12 may be less than the thickness of the first composite material layer 12 in another region. In the upper region of the second substrate 21 adjacent to the second terminal tab 23, the thickness of the second composite material layer 22 may be less than the thickness of the second composite material layer 22 in another region.

[0048] The first composite substance layer 12 may have a thickness greater than that of the second composite substance layer 22. The thickness difference between regions of the first composite substance layer 12 may be greater than the thickness difference between regions of the second composite substance layer 22. If a single stack 40 is manufactured by stacking ten to twenty first electrode plates 10 and ten to twenty second electrode plates 20, the thickness differences of the composite substance layers 12, 22 are accumulated, which may result in a greater thickness difference.

[0049] Figure 5 According to one or more embodiments, Figure 1 A cross-sectional view of the electrode assembly taken along line BB in FIG.

[0050] refer to Figure 1 and Figure 5, the cell stack 40 may include a first portion 41 having a first thickness t1 and a second portion 42 having a second thickness t2 less than the first thickness t1. The second portion 42 may correspond to an upper portion of the first substrate 11 adjacent to the first terminal tab 13 and an upper portion of the second substrate 21 adjacent to the second terminal tab 23, and occupy an area smaller than that of the first portion 41 in the cell stack 40. The second portion 42 may be adjacent to an upper edge of the cell stack 40.

[0051] The electrode assembly 120 may include a correction sheet 50 located on the second portion 42 of the cell stack 40 and configured to make the thickness of the cell stack 40 uniform, and a pair of first fixing portions 61 attached to the left and right edges of the cell stack 40. In this case, the pair of first fixing portions 61 may each include a portion overlapping the correction sheet 50. For convenience, Figure 2 The first fixing portion 61 is omitted.

[0052] The electrode assembly 120 may further include a second fixing portion 62 attached to a lower edge of the cell stack 40. The pair of the first fixing portion 61 and the second fixing portion 62 serves to maintain a constant shape and thickness of the cell stack 40.

[0053] The size of the correction sheet 50 may be equal to the size of the second portion 42. The correction sheet 50 may be adjacent to the upper edge of the monomer stack 40, and the width of the correction sheet 50 may be equal to the width of the monomer stack 40. The upper edge of the monomer stack 40 may be referred to as a first edge, the left edge and the right edge may be referred to as a second edge and a third edge and intersect with the first edge, and the lower edge may be referred to as a fourth edge and is parallel to the first edge and intersects with the second edge and the third edge.

[0054] The correction sheet 50 may be attached to any one of the front surface and the rear surface of the second portion 42, or to both of the front surface and the rear surface. In both cases, the sum of the thickness of the second portion 42 (the second thickness t2) and the thickness of the correction sheet 50 may be equal to the thickness of the first portion 41 (the first thickness t1). That is, the number of correction sheets 50 and the thickness of the correction sheets 50 may be appropriately selected in consideration of the thickness difference between the first portion 41 and the second portion 42.

[0055] The calibration sheet 50 may be configured as a polymer film having an adhesive layer, for example, a film made of polyimide (PI) or polyethylene terephthalate (PET). A pair of first fixing portions 61 and a second fixing portion 62 may each be configured as a polymer film having an adhesive layer. The calibration sheet 50, a pair of first fixing portions 61, and a second fixing portion 62 may be configured as polymer films made of the same material.

[0056] After the plurality of first electrode plates 10 and the plurality of second electrode plates 20 are alternately disposed one by one between the separators 30 folded in a zigzag pattern, the cell stack 40 may be pressed by a heat press apparatus. The cell stack 40 may be loaded into the heat press apparatus after the correction sheet 50 is attached to the second portion 42.

[0057] Figure 6 is an example of a heat pressing device and Figure 5 Schematic diagram of a cell stack illustrated in FIG.

[0058] refer to Figure 2 and Figure 6 , the cell stack 40 in which the correction sheet 50 is attached to the second portion 42 may be loaded into the hot pressing device 200, and the cell stack 40 may be compressed in the thickness direction by the operation of the hot pressing device 200. The hot pressing device 200 firmly connects the first electrode plate 10, the separator 30, and the second electrode plate 20 by pressing the cell stack 40. If the firmly connected state between the first electrode plate 10, the separator 30, and the second electrode plate 20 is maintained, ion conductivity may be improved during the charge / discharge process, which may ensure output characteristics of the rechargeable battery.

[0059] The correction sheet 50 attached to the second portion 42 transfers the pressure of the heat pressing device 200 to the second portion 42, so that the second portion 42 is pressed by the same pressure as that of the first portion 41. Therefore, both the first portion 41 and the second portion 42 of the single stack 40 can receive uniform pressure, so that the connection force between the first electrode plate 10, the separator 30, and the second electrode plate 20 can be increased, and the overall thickness can be uniformized.

[0060] Figure 7 is an example based on (with Figure 6 Schematic diagram of the hot pressing device and the monomer stack of the comparative example (Comparison).

[0061] refer to Figure 7 , the single stack 40a of the comparative example may include Figure 6 The first and second parts 41 and 42 are identical to the first and second parts 41 and 42, but do not include the correction sheet 50. The protruding portion 70 corresponding to the second part 42 may be located on the heat pressing device 201 of the comparative example.

[0062] The second portion 42 of the monomer stack 40a may be pressed by the protruding portion 70. However, in the case of the pressing method of the comparative example, the monomer stack 40a may move during the process of setting the monomer stack 40a on the heat pressing device 201 and the process of pressing the monomer stack 40b by the heat pressing device 201, which may cause position dispersion. In this case, uniform pressing on the monomer stack 40a may be deteriorated.

[0063] Return to reference Figure 6 , since the correction sheet 50 is attached to the second portion 42 in advance, even if position dispersion of the monomer stack 40 occurs during the process of placing the monomer stack 40 on the heat press device 200 and the process of pressing the monomer stack 40 by the heat press device 200, uniform pressing on the monomer stack 40 is ensured. In addition, Figure 6 The pressing method may not include the protruding portion 70 of the comparative example, which may simplify the configuration of the heat pressing device 200.

[0064] Return to reference Figure 1 and Figure 5 , a pair of first fixing parts 61 and a second fixing part 62 may be attached to the monomer stack 40 after the hot pressing process. However, the present disclosure is not limited to this order. A pair of first fixing parts 61 may be located at the left and right edges of the monomer stack 40 on the front surface, side surface, and rear surface of the monomer stack 40. The second fixing part 62 may be located at the lower edge of the monomer stack 40 on the front surface, side surface, and rear surface of the monomer stack 40. A pair of first fixing parts 61 and a second fixing part 62 maintain a constant shape and thickness of the monomer stack 40.

[0065] The pair of first fixing portions 61 each include a portion overlapping the correction sheet 50. That is, the pair of first fixing portions 61 may overlap the correction sheet 50 while covering the left and right edges of the correction sheet 50. Therefore, the correction sheet 50 may be attached to the single body stack 40 by its own adhesive layer and overlap the first fixing portions 61, thereby fixing the position more firmly.

[0066] Return to reference Figure 1 , a plurality of first terminal tabs 13 may overlap each other and be fixed as a whole by a method such as welding. A plurality of second terminal tabs 23 may overlap each other and be fixed as a whole by a method such as welding. The first lead terminal tab 81 may be fixed to the plurality of first terminal tabs 13, and the second lead terminal tab 82 may be fixed to the plurality of second terminal tabs 23.

[0067] The first lead tab 81 may be a terminal (e.g., a negative electrode terminal) of the first electrode plate 10, and the second lead tab 82 may be a terminal (e.g., a positive electrode terminal) of the second electrode plate 20. The joint portions between the plurality of first tabs 13 and the first lead tab 81 and the joint portions between the plurality of second tabs 23 and the second lead tab 82 may be surrounded by the sealing tape 83, and the joint portions surrounded by the sealing tape 82 may overlap with the sealing portion 133 of the housing 130.

[0068] according to Figure 1In the rechargeable battery 100 of the present invention, the correction sheet 50 can make the thickness of the electrode assembly 120 uniform and increase the connection force between the first electrode plate 10, the separator 30, and the second electrode plate 20 in the entire electrode assembly 120. Therefore, the increased connection force between the electrode plates 10, 20 and the separator 30 of the rechargeable battery 100 can improve output characteristics and output stability.

[0069] Figure 8 is a perspective view of an electrode assembly of a rechargeable battery according to one or more embodiments. Fig. 9 According to one or more embodiments, Figure 8 A cross-sectional view of the electrode assembly taken along line CC in FIG. Fig.10 According to one or more embodiments, Figure 8 In addition to the third fixing portion and the fourth fixing portion to be described below, Figure 8 The rechargeable battery can be configured with Figure 1 The rechargeable battery in is the same or similar.

[0070] refer to Figure 8 to Figure 10 , the electrode assembly 120 may include a third fixing portion 63. The third fixing portion 63 may be attached to the upper edge of the cell stack 40 and may have a portion overlapping the correction sheet 50. The third fixing portion 63 may be provided between the plurality of first terminal tabs 13 and the plurality of second terminal tabs 23 and located at a predetermined distance from the plurality of first terminal tabs 13 and the plurality of second terminal tabs 23.

[0071] The third fixing portion 63 may be located at the first edge on a portion of the front surface, the side surface, and the rear surface of the monomer stack 40. Specifically, the third fixing portion 63 may be located on the outer surface of the correction sheet 50 fixed to the front surface of the monomer stack 40, the side surface of the monomer stack 40, and the outer surface of the correction sheet 50 attached to the rear surface of the monomer stack 40. The third fixing portion 63 may be configured as a polymer film having an adhesive layer and including a polymer film made of the same material as that of the correction sheet 50. The third fixing portion 63 is used to maintain a constant shape and thickness of the monomer stack 40 at the upper edge of the monomer stack 40.

[0072] The electrode assembly 120 may further include a fourth fixing portion 64. The fourth fixing portion 64 surrounds the plurality of first terminal tabs 13 and the plurality of second terminal tabs 23 at the same time, and has a portion overlapping the correction sheet 50 and the third fixing portion 63. The fourth fixing portion 64 may overlap a portion of the upper side of the correction sheet 50 and a portion of the upper side of the third fixing portion 63. The horizontal width of the fourth fixing portion 64 may be set to be smaller than the distance between the pair of first fixing portions 61.

[0073] The fourth fixing portion 64 may be configured as a polymer film having an adhesive layer, and may include the same polymer film as that of the correction sheet 50 and the third fixing portion 63. The fourth fixing portion 64 may more reliably fix the positions of the correction sheet 50 and the third fixing portion 63 at the upper edge of the unit stack 40. The fourth fixing portion 64 may protect the plurality of first terminals 13 and the plurality of second terminals 23 when the housing 130 is thermally bonded.

[0074] Table 1 below shows measurement results of thicknesses of electrode assemblies according to four examples and an electrode assembly according to a comparative example. In the following table, final thickness means the thickness of the electrode assembly after assembling the electrode assembly and the case and completing the forming process.

[0075] Table 1

[0076]

[0077]

[0078] Fig.11 is a schematic diagram illustrating electrode assemblies according to Examples 1 to 4 and Comparative Example in Table 1 above.

[0079] refer to Fig.11 The electrode assembly 120A according to embodiments 1 and 2 corresponds to Figure 1 The electrode assembly 120 illustrated in the embodiment 1 includes a single stack 40, two correction sheets 50, two first fixing parts 61 and a second fixing part 62. The two correction sheets 50 may be located on the front surface and the rear surface of the second part 42. In the electrode assembly 120A according to the embodiment 1, the two correction sheets 50 each have a thickness of 56 μm. In the electrode assembly 120A according to the embodiment 2, the two correction sheets 50 each have a thickness of 30 μm.

[0080] The electrode assembly 120B according to the third and fourth embodiments corresponds to Figure 8 The electrode assembly 120 illustrated in the embodiment 1 includes a single stack 40, two correction sheets 50, two first fixing parts 61, and second to fourth fixing parts 62, 63, and 64. The two correction sheets 50 may be located on the front surface and the rear surface of the second part 42. In the electrode assembly 120B according to the embodiment 3, the two correction sheets 50 each have a thickness of 56 μm. In the electrode assembly 120B according to the embodiment 4, the two correction sheets 50 each have a thickness of 30 μm.

[0081] according to Figure 7 The electrode assembly 220 of the comparative example includes a cell stack 40 , two first fixing portions 61 , a second fixing portion 62 , and a third fixing portion 63 .

[0082] The measurement positions high (P1) / middle (P2) / low (P3) for measuring the thickness of the electrode assemblies 120A, 120B, and 220 may be located side by side. Fig.11 The measuring position high (P1) may be a point on the second portion 42, and the measuring position low (P3) may be a point of the second fixing portion 62 closer to the lower edge of the unit stack 40. The measuring position medium (P2) may be located between P1 and P3 and may correspond to the first portion 41.

[0083] According to the results shown in Table 1, it can be determined that, compared with the electrode assembly 220 according to the comparative example, in the electrode assemblies 120A, 120B according to the embodiments 1 to 4 having the correction sheet 50, the thickness difference between the positions P1 to P3 is reduced and the thickness uniformity is improved. The improvement in the thickness uniformity of the electrode assemblies 120A, 120B leads to the improvement of the output characteristics and output stability of the rechargeable battery.

[0084] The present disclosure provides a rechargeable battery capable of uniformizing the thickness of an electrode assembly, increasing the connection force between a positive electrode plate, a separator, and a negative electrode plate in the entire electrode assembly, and improving output characteristics and output stability.

[0085] In a rechargeable battery according to one or more embodiments, the correction sheet can make the thickness of the electrode assembly uniform and increase the connection force between the first electrode plate, the separator, and the second electrode plate in the entire electrode assembly. Therefore, the output characteristics and output stability of the rechargeable battery can be improved by the increased connection force between the electrode plate and the separator.

[0086] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications may be made and performed within the scope of the claims, specific embodiments, and drawings, and these modifications also fall within the scope of the present disclosure.

[0087] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted in a general and descriptive sense only and not for purposes of limitation. In some cases, as will be apparent to one of ordinary skill in the art when filing this application, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise specifically stated. Accordingly, one of ordinary skill in the art will understand that various changes may be made in form and detail without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A rechargeable battery comprising: Electrode assembly; and A housing configured to contain and seal the electrode assembly, wherein the electrode assembly comprises: a single body stack including a plurality of first electrode plates and a plurality of second electrode plates alternately stacked one by one with a separator interposed therebetween, the single body stack including a first portion having a first thickness and a second portion having a second thickness smaller than the first thickness; a calibration sheet located on the second portion and configured to make the thickness of the single-piece stack uniform; and A pair of first fixing portions are located on a portion of the front surface, the side surface, and the rear surface of the single body stack, and the pair of first fixing portions have portions overlapping with the correction sheet.

2. The rechargeable battery according to claim 1, wherein the calibration sheet comprises a pair of calibration sheets respectively located on a front surface and a rear surface of the second portion. 3 . The rechargeable battery according to claim 2 , wherein each of the pair of correction sheets is configured as a polymer film having an adhesive layer. 4 . The rechargeable battery of claim 1 , wherein the cell stack has a uniform thickness by being pressed by a heat press device after the correction sheet is attached to the second portion.

5. The rechargeable battery according to claim 1, wherein: The single stack includes a first edge and a second edge and a third edge intersecting the first edge, At the first edge, a plurality of first tabs extend from the plurality of first electrode plates and a plurality of second tabs extend from the plurality of second electrode plates, and The second portion and the correction sheet are positioned adjacent to the first edge. 6 . The rechargeable battery of claim 5 , wherein the second portion and the correction sheet each have a width equal to a width of the cell stack.

7. A rechargeable battery according to claim 5, wherein the pair of first fixing portions are located on a portion of the front surface, the side surface and the rear surface of the single-cell stack at the second edge and the third edge, and overlap with the correction sheet on at least one of the front surface and the rear surface of the single-cell stack.

8. The rechargeable battery according to claim 5, wherein: The single body stack includes a fourth edge parallel to the first edge and intersecting the second edge and the third edge, and The electrode assembly further includes a second fixing portion located on a portion of the front surface, the side surface, and the rear surface of the cell stack at the fourth edge.

9. The rechargeable battery according to claim 5, wherein: The electrode assembly further includes a third fixing portion located between the plurality of first terminal tabs and the plurality of second terminal tabs at the first edge, and The third fixing portion is located on a portion of the front surface, the side surface, and the rear surface of the unit stack at the first edge, and the third fixing portion includes a portion overlapping the correction sheet. 10 . The rechargeable battery of claim 5 , wherein the electrode assembly further comprises a fourth fixing portion configured to surround the plurality of first tabs and the plurality of second tabs.

11. A rechargeable battery comprising: Electrode assembly; and A housing configured to contain and seal the electrode assembly, wherein the electrode assembly comprises: a single body stack including a separator folded multiple times in a zigzag pattern, and a plurality of first electrode plates and a plurality of second electrode plates alternately stacked one by one with the separator interposed therebetween, the single body stack being divided into a first portion and a second portion, the second portion having a thickness smaller than that of the first portion; a pair of correction sheets provided on the second portion and located on the front and rear surfaces of the single-unit stack to make the thickness of the single-unit stack uniform; and A plurality of fixing portions are attached to the edge of the single stack and on the front surface, the side surface and the rear surface of the single stack, the plurality of fixing portions having portions overlapping with the pair of correction sheets while covering the pair of correction sheets from the outside.

12. The rechargeable battery according to claim 11, wherein: The single stack includes a first edge and a second edge and a third edge intersecting the first edge, At the first edge, a plurality of first tabs extend from the plurality of first electrode plates and a plurality of second tabs extend from the plurality of second electrode plates, and The second portion and the pair of calibration plates are positioned adjacent to the first edge.

13. The rechargeable battery according to claim 12, wherein: The plurality of fixing portions include a pair of first fixing portions, and The pair of first fixing portions are attached to the pair of correction sheets and the single body stack at the second edge and the third edge.

14. The rechargeable battery according to claim 13, wherein: The plurality of fixing portions further include a third fixing portion, and The third fixing portion is provided between the plurality of first tabs and the plurality of second tabs at the first edge, and is attached to the pair of correction sheets and the cell stack.

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