Secondary battery

Abstract

A secondary battery includes an electrode assembly, which includes a positive electrode plate having a positive electrode uncoated portion, a negative electrode plate having a negative electrode uncoated portion, and a separator between the positive electrode plate and the negative electrode plate. The positive electrode uncoated portion and the negative electrode uncoated portion are exposed on opposite sides of the electrode assembly. The secondary battery also includes: a shell having a top opening and an internal space for accommodating the electrode assembly; a cover plate sealing the top opening of the shell; a positive electrode current collector plate perpendicular to and welded to the positive electrode uncoated portion; a negative electrode current collector plate perpendicular to and welded to the negative electrode uncoated portion; a positive electrode terminal on the cover plate and electrically connected to the positive electrode current collector plate; and a negative electrode terminal on the cover plate and electrically connected to the negative electrode current collector plate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0120630 filed in the Korean Intellectual Property Office on September 30, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Aspects of embodiments of the present disclosure relate to secondary batteries. Background Art

[0004] Unlike primary batteries, secondary batteries can be charged and discharged repeatedly. Low-capacity secondary batteries are used in various small portable electronic devices such as mobile phones, portable cameras or laptop computers, and high-capacity secondary batteries are widely used as power sources, energy storage units, etc. for driving electronic devices such as motors of hybrid vehicles or electric vehicles.

[0005] In addition, according to the shape of the secondary battery, the secondary battery can be classified into a cylindrical type, a prismatic type or a pouch type. Among other things, a prismatic secondary battery may include an electrode assembly, a case having a rectangular parallelepiped shape and accommodating the electrode assembly and an electrolyte, a cap plate sealing the case, and an electrode terminal mounted on the cap plate.

[0006] The above information disclosed in this Background section is only for enhancement of understanding of the background of the technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the invention

[0007] Embodiments of the present disclosure are directed to a secondary battery capable of increasing battery capacity and improving welding quality compared to a related art secondary battery.

[0008] According to an embodiment of the present disclosure, a secondary battery includes: an electrode assembly, including a positive electrode plate having a positive electrode uncoated portion, a negative electrode plate having a negative electrode uncoated portion, and a separator between the positive electrode plate and the negative electrode plate, the positive electrode uncoated portion and the negative electrode uncoated portion being exposed on opposite sides of the electrode assembly; a shell having a top opening and an internal space for accommodating the electrode assembly; a cover plate sealing the top opening of the shell; a positive electrode current collecting plate perpendicular to and welded to the positive electrode uncoated portion; a negative electrode current collecting plate perpendicular to and welded to the negative electrode uncoated portion; a positive electrode terminal on the cover plate and electrically connected to the positive electrode current collecting plate; and a negative electrode terminal on the cover plate and electrically connected to the negative electrode current collecting plate.

[0009] In addition, the electrode assembly may further include a second separator, and the positive electrode plate, the separator, the negative electrode plate, and the second separator may be sequentially stacked.

[0010] In addition, the positive electrode current collecting plate and / or the negative electrode current collecting plate may have an area equal to a cross-sectional area of ​​the electrode assembly.

[0011] In addition, the electrode assembly can be wound into a jelly roll structure around a winding axis so that the positive electrode uncoated portion is exposed at one end of the winding axis, the negative electrode uncoated portion is exposed at the other end of the winding axis, and the winding axis is parallel to the top opening.

[0012] In addition, the electrode assembly may have a cross-section elongated in an up-down direction, the cross-section being perpendicular to the winding axis, and may include a plurality of electrode assemblies stacked on each other in a direction transverse to the up-down direction.

[0013] In addition, the positive electrode current collecting plate and / or the negative electrode current collecting plate may have an area equal to a total area of ​​the cross-sections of the plurality of electrode assemblies.

[0014] In addition, the positive electrode uncoated portion may be in line contact with the positive electrode current collecting plate, and the negative electrode uncoated portion may be in line contact with the negative electrode current collecting plate.

[0015] In addition, the entirety of the positive electrode current collecting plate may contact the entirety of the positive electrode uncoated portion, and the entirety of the negative electrode current collecting plate may contact the entirety of the negative electrode uncoated portion.

[0016] As described above, according to various embodiments of the present disclosure, since the uncoated portion of the electrode is in line contact with the electrode current collecting plate, the area of ​​the uncoated portion of the electrode can be reduced compared to the secondary battery of the related art in which the uncoated portion of the electrode is in surface contact with the electrode current collecting plate, thereby increasing the battery capacity and ultimately simplifying the manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present disclosure.

[0018] Figure 2 is an exploded view of a secondary battery according to an embodiment of the present disclosure.

[0019] Figure 3 is an exploded view of a secondary battery according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described in detail.

[0021] However, the embodiments of the present disclosure may be modified in many different forms and should not be interpreted as being limited to the example (or exemplary) embodiments set forth herein. On the contrary, these example embodiments are provided so that the present disclosure will be comprehensive and complete and will convey the various aspects and features of the present disclosure to those skilled in the art.

[0022] In addition, in the accompanying drawings, the size or thickness of various components is exaggerated for the sake of brevity and clarity. The same reference numerals always refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. In addition, it will be understood that when element A is referred to as being "connected to" element B, element A can be directly connected to element B, or an intermediate element C can be present between element A and element B so that element A and element B are indirectly connected to each other.

[0023] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular form is also intended to include the plural form, unless the context clearly indicates otherwise. It will also be understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of the features, numbers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts and / or combinations thereof.

[0024] It will be understood that although the terms first, second, etc. may be used herein to describe various components, elements, regions, layers, and / or sections, these components, elements, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one component, element, region, layer, and / or section from another component, element, region, layer, and / or section. Thus, for example, the first component, first element, first region, first layer, and / or first section discussed below may be referred to as the second component, second element, second region, second layer, and / or second section without departing from the teachings of the present disclosure.

[0025] For ease of description, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the elements or features in the figures are flipped, elements described as being "below" or "beneath" other elements or features would then be oriented as being "above" or "above" the other elements or features. Thus, the exemplary term "below" may encompass both above and below orientations.

[0026] Figure 1is a perspective view of a secondary battery 100 according to an embodiment of the present disclosure, Figure 2 FIG. 1 is an exploded view of a secondary battery 100 according to an embodiment of the present disclosure.

[0027] See also Figure 1 and Figure 2 , a secondary battery 100 according to an embodiment includes an electrode assembly 110 , a case 120 , a cap plate 130 , a positive electrode current collecting plate 140 , a negative electrode current collecting plate 150 , a positive electrode terminal 160 , and a negative electrode terminal 170 .

[0028] The electrode assembly 110 includes a positive electrode plate 111 , a negative electrode plate 112 , and a separator 113 between the positive electrode plate 111 and the negative electrode plate 112 .

[0029] The positive electrode plate 111 has a positive electrode coated portion on which a positive electrode active material is coated and a positive electrode uncoated portion 111A on which the positive electrode active material is not coated. The positive electrode coated portion is formed by coating a positive electrode active material (including, for example, a transition metal oxide) on a positive electrode collector made of, for example, aluminum foil, and the positive electrode uncoated portion 111A is formed along one side of the positive electrode collector.

[0030] In addition, the negative electrode plate 112 has a negative electrode coating portion on which a negative electrode active material is coated and a negative electrode uncoated portion 112A on which the negative electrode active material is not coated. The negative electrode coating portion is formed by coating a negative electrode active material (including, for example, carbon or graphite) on a negative electrode current collector made of, for example, copper or nickel foil, and the negative electrode uncoated portion 112A is formed along one side of the negative electrode current collector.

[0031] The separator 113 is an insulator and may be made of, for example, polyethylene, polypropylene, or a composite film of polypropylene and polyethylene. The separator 113 is located between the positive electrode plate 111 and the negative electrode plate 112 to prevent a short circuit from occurring between the positive electrode plate 111 and the negative electrode plate 112 and to allow lithium ions to move.

[0032] The electrode assembly 110 including the positive electrode plate 111, the negative electrode plate 112, and the separator 113 is wound around a winding axis into a so-called jelly roll structure. In one or more embodiments, the positive electrode uncoated portion 111A is wound around the winding axis to be exposed at one end of the winding axis, and the negative electrode uncoated portion 112A is wound around the winding axis to be exposed at the other end of the winding axis. Figure 2 , the winding axis is arranged along the X-axis direction, the positive electrode uncoated portion 111A is exposed on the negative (-) side of the X-axis direction, and the negative electrode uncoated portion 112A is exposed on the positive (+) side of the X-axis direction. Accordingly, in the illustrated embodiment, the winding axis is parallel to the top opening of the housing 120.

[0033] In addition, in one or more embodiments, the cross-sectional shape of the electrode assembly 110 in a plane perpendicular to the winding axis (e.g., YZ plane) may be circular, or may be an ellipse or rectangle elongated in the Z-axis direction. Accordingly, in one or more embodiments, the electrode assembly 100 has a cross-section elongated in the up-down direction (i.e., in the direction of the Z-axis) in a plane perpendicular to the winding axis (e.g., YZ plane). In addition, in the illustrated embodiment, a plurality of electrode assemblies 100 are stacked in a direction transverse to the up-down direction (e.g., a plurality of electrode assemblies 100 are stacked in the Y-axis direction).

[0034] In addition, the electrode assembly 110 may include a plurality of electrode assemblies stacked adjacent to each other along the Y-axis direction.

[0035] The case 120 is in a generally rectangular parallelepiped shape having an inner space and a top opening (eg, an open top). Accordingly, the inner space of the case 120 may be used to accommodate the electrode assembly 110 and the electrolyte.

[0036] For example, the electrolyte may include an organic solvent such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and a solvent such as LiPF 6 or LiBF 4 of lithium salts.

[0037] The cover plate 130 is coupled to the top end of the housing 120 and seals the top end of the housing 120 (eg, the cover plate 130 covers or closes the top opening of the housing 120). The housing 120 and the cover plate 130 may be made of, for example, aluminum and welded together.

[0038] In addition, the cap plate 130 may have an electrolyte injection hole and a vent hole.

[0039] The electrolyte injection hole is provided for injecting electrolyte into the inner space of the case 120 after the cap plate 130 is coupled to the case 120. Once the electrolyte is injected, the electrolyte injection hole is sealed by the stopper 131.

[0040] The vent hole is configured to discharge or exhaust internal gas generated inside the housing 120, and thereby prevent explosion caused by the internal gas generated inside the housing 120. The vent hole is normally sealed by the vent member 132, and is opened due to the natural rupture of the vent member 132 when the internal pressure of the housing 120 reaches a certain level (for example, the vent member 132 is configured to rupture when the inside of the housing 120 reaches a threshold internal pressure). In addition, the vent member 132 may have a notch 132A formed therein, the notch 132A being configured to facilitate rupture of the vent member 132 around the notch 132A.

[0041] The positive electrode current collecting plate 140 may be formed, for example, of an aluminum plate and may be perpendicular to the positive electrode uncoated portion 111A. The positive electrode current collecting plate 140 may be welded to the positive electrode uncoated portion 111A. In one or more embodiments, the positive electrode uncoated portion 111A is in line contact with the positive electrode current collecting plate 140. With this structure, the area of ​​the positive electrode uncoated portion 111A may be reduced compared to an embodiment in which the positive electrode uncoated portion 111A is in surface contact with the positive electrode current collecting plate 140, thereby increasing the battery capacity of the secondary battery 100.

[0042] In addition, the positive electrode current collecting plate 140 may be formed to have an area equal to or substantially equal to the total area of ​​the cross-sections of the positive electrode uncoated portions 111A of the plurality of electrode assemblies 110, and thus the entirety or substantially the entirety of the positive electrode current collecting plate 140 may contact the entirety or substantially the entirety of the positive electrode uncoated portions 111A of the plurality of electrode assemblies 110. Accordingly, the resistance between the positive electrode uncoated portions 111A and the positive electrode current collecting plate 140 may be minimized or at least reduced, compared to a secondary battery not having such a configuration.

[0043] In one or more embodiments, the positive electrode current collector plate 140 may be welded to the positive electrode uncoated portion 111A by laser. In this embodiment, during the operation of laser welding the positive electrode current collector plate 140 to the positive electrode uncoated portion 111A, the laser may be irradiated along the Y-axis direction. In other words, the laser welding line that joins the positive electrode current collector plate 140 to the positive electrode uncoated portion 111A may be formed along the Y-axis direction. In one or more embodiments, the laser may be irradiated with an appropriate intensity so as not to completely melt the positive electrode current collector plate 140 or the positive electrode uncoated portion 111A. If the irradiated laser is strong enough to completely melt the positive electrode current collector plate 140, foreign matter (e.g., splashed matter) may be directed to the electrode assembly 110, which may cause a short circuit or other damage to the secondary battery 100. However, if the irradiated laser intensity is not enough to completely melt the positive electrode current collector plate 140, the above problems may be avoided.

[0044] In addition, since the electrode assembly 110 is wound into a jelly roll structure, the self-supporting ability of the positive electrode uncoated portion 111A can be increased by its curvature. Therefore, when the positive electrode current collecting plate 140 is pressed against the positive electrode uncoated portion 111A, the positive electrode uncoated portion 111A can be prevented from being undesirably deformed.

[0045] In addition, since the electrode assembly 110 includes a plurality of electrode assemblies, each of the plurality of electrode assemblies can be relatively narrow and long for a given internal volume of the case 120, compared to an embodiment in which the electrode assembly 110 includes only a single electrode assembly. By allowing the positive electrode uncoated portion 111A to have a greater curvature at its top and bottom ends, the self-supporting ability of the positive electrode uncoated portion 111A can be further increased, which also improves the welding quality between the positive electrode uncoated portion 111A and the positive electrode current collecting plate 140.

[0046] The negative electrode current collecting plate 150 may be formed of, for example, a copper plate or a nickel plate, and may be perpendicular to the negative electrode uncoated portion 112A. The negative electrode current collecting plate 150 may be welded to the negative electrode uncoated portion 112A. In one or more embodiments, the negative electrode uncoated portion 112A may be in line contact with the negative electrode current collecting plate 150.

[0047] The negative electrode current collecting plate 150 may also be formed to have an area equal to or substantially equal to the total area of ​​the cross-sections of the negative electrode uncoated portions 112A of the plurality of electrode assemblies 110 , so that the entirety or substantially the entirety of the negative electrode current collecting plate 150 may contact the entirety or substantially the entirety of the negative electrode uncoated portions 112A of the plurality of electrode assemblies 110 .

[0048] In one or more embodiments, the negative electrode current collecting plate 150 may be laser welded to the negative electrode uncoated portion 112A. In this embodiment, during the operation of laser welding the negative electrode current collecting plate 150 to the negative electrode uncoated portion 112A, the laser may be irradiated along the Y-axis direction with an appropriate intensity so as not to completely melt the negative electrode current collecting plate 150 or the negative electrode uncoated portion 112A.

[0049] Since the produced effects are substantially the same as those described above with respect to the positive electrode current collecting plate 140 and the positive electrode uncoated portion 111A, a repeated description thereof will be omitted.

[0050] The positive electrode terminal 160 is mounted on the cap plate 130 and is electrically connected to the positive electrode current collecting plate 140 .

[0051] In addition, the negative electrode terminal 170 is mounted on the cap plate 130 and is electrically connected to the negative electrode current collecting plate 150 .

[0052] If the positive electrode terminal 160 contacts the cap plate 130 , the insulating member 180 is provided between the negative electrode terminal 170 and the cap plate 130 (eg, the negative electrode terminal 170 is spaced apart and electrically isolated from the cap plate 130 by the insulating member 180 ) to prevent a short circuit.

[0053] Figure 3 FIG. 2 is an exploded view of a secondary battery 200 according to another embodiment of the present disclosure.

[0054] The secondary battery 200 according to another embodiment is similar to the above-mentioned Figure 1 and Figure 2 The secondary battery 100 described is different in that the former includes an electrode assembly 210 in a stacked configuration, and other details are substantially the same in both embodiments, so repeated descriptions of common components and / or features will be omitted. Figure 3 The embodiments shown and Figure 1-Figure 2 Common components and / or features of the illustrated embodiments are identified with the same reference numerals.

[0055] See also Figure 3 , the electrode assembly 210 includes a positive electrode plate 211, a separator 213, a negative electrode plate 212, and another separator 213 stacked in the following order. In the resulting stack, the positive electrode uncoated portion 211A and the negative electrode uncoated portion 212A are exposed on opposite sides. Figure 3 In the embodiment, the positive electrode uncoated portion 211A is exposed on the negative (-) side in the X-axis direction, and the negative electrode uncoated portion 212A is exposed on the positive (+) side in the X-axis direction.

[0056] In the illustrated embodiment, the secondary battery 200 further includes a positive electrode current collecting plate 240 and a negative electrode current collecting plate 250 coupled to the cap plate 130. The positive electrode current collecting plate 240 may be perpendicular to the positive electrode uncoated portion 211A, and the positive electrode current collecting plate 240 may be welded to the positive electrode uncoated portion 211A (e.g., by laser). The positive electrode current collecting plate 240 has an area equal to or substantially equal to the cross-sectional area of ​​the electrode assembly 210 in the YZ plane.

[0057] The negative electrode current collecting plate 250 may be perpendicular to the negative electrode uncoated portion 212A and may be welded to the negative electrode uncoated portion 212A (eg, by laser). The negative electrode current collecting plate 250 has an area equal to or substantially equal to the cross-sectional area of ​​the electrode assembly 210 in the YZ plane.

[0058] In one or more embodiments, the positive electrode current collecting plate 240 and the negative electrode current collecting plate 250 may each have a thickness of, for example, greater than or equal to about 1 mm.

[0059] While the foregoing embodiments have been described for practicing the secondary battery of the present disclosure, those skilled in the art will understand that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0060] Description of Reference Numerals

[0061] 100, 200: Secondary battery

[0062] 110, 210: Electrode assembly

[0063] 111, 211: Positive electrode plate

[0064] 111A, 211A: Uncoated part of positive electrode

[0065] 112, 212: Negative electrode plate

[0066] 112A, 212A: Uncoated part of negative electrode

[0067] 113, 213: Partition

[0068] 120: Shell

[0069] 130: Cover

[0070] 131: Stopper

[0071] 132: Ventilation components

[0072] 132A: Notch

[0073] 140, 240: Positive electrode current collector

[0074] 150, 250: Negative electrode current collector

[0075] 160: Positive electrode terminal

[0076] 170: Negative electrode terminal

[0077] 180: Insulation components

Claims

1. A secondary battery comprising: an electrode assembly comprising a positive electrode plate having a positive electrode uncoated portion, a negative electrode plate having a negative electrode uncoated portion, and a separator between the positive electrode plate and the negative electrode plate, the positive electrode uncoated portion and the negative electrode uncoated portion being exposed on opposite sides of the electrode assembly; a housing having a top opening and an inner space for accommodating the electrode assembly; a cover plate, sealing the top opening of the housing; a positive electrode current collecting plate, perpendicular to the positive electrode uncoated portion and welded to the positive electrode uncoated portion along a first welding line; a negative electrode current collecting plate, perpendicular to the negative electrode uncoated portion and welded to the negative electrode uncoated portion along a second welding line; a positive electrode terminal disposed on the cap plate and electrically connected to the positive electrode current collecting plate; as well as a negative electrode terminal on the cap plate and electrically connected to the negative electrode current collecting plate, wherein the electrode assembly includes a plurality of electrode assemblies, each of the plurality of electrode assemblies being wound into a jelly roll structure around a winding axis, and at least one of the positive electrode current collecting plate and the negative electrode current collecting plate has an area equal to a total area of ​​a cross section of the plurality of electrode assemblies, wherein the first welding line extends continuously on the plurality of electrode assemblies, and The second welding line extends continuously on the plurality of electrode assemblies.

2. The secondary battery according to claim 1, wherein the positive electrode uncoated portion is exposed at one end of the winding axis, wherein the negative electrode uncoated portion is exposed at the other end of the winding axis, and wherein the winding axis is parallel to the top opening. 3 . The secondary battery according to claim 2 , wherein each of the plurality of electrode assemblies has a cross section elongated in an up-and-down direction, the cross section being perpendicular to the winding axis, and wherein the plurality of electrode assemblies are stacked in a direction transverse to the up-and-down direction. 4 . The secondary battery according to claim 1 , wherein the positive electrode uncoated portion is in line contact with the positive electrode current collecting plate. 5 . The secondary battery according to claim 1 , wherein the negative electrode uncoated portion is in line contact with the negative electrode current collecting plate. 6 . The secondary battery according to claim 1 , wherein an entirety of the positive electrode current collecting plate contacts an entirety of the positive electrode uncoated portion. 7 . The secondary battery according to claim 1 , wherein an entirety of the negative electrode current collecting plate contacts an entirety of the negative electrode uncoated portion.

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