Electrode assembly and secondary battery including the electrode assembly

Abstract

In an electrode assembly according to one embodiment of the present invention, the electrode assembly is provided by alternately stacking electrodes and separators in a predetermined stacking direction, wherein the electrode located at the outermost position among the electrodes is defined as the outermost electrode, and the separator located outside the outermost electrode among the separators is defined as the outermost separator, the end portion of the outermost separator may be provided to press the end portion of the outermost electrode inward in the stacking direction.

Description

Technology Field

[0001] The present invention relates to an electrode assembly and a secondary battery comprising the electrode assembly. Background Technology

[0002] Research and development on power generation based on eco-friendly energy are underway to address environmental pollution caused by the excessive use of fossil fuels and to resolve energy shortages resulting from the depletion of fossil fuels. Recently, research on rechargeable secondary batteries has been actively conducted, covering various aspects such as materials, structure, processes, stability, and durability.

[0003] A secondary battery is equipped with an electrode assembly inside, and the electrode assembly can be formed by alternately stacking electrodes having different poles and separators. The secondary battery produces electrical energy based on electrochemical reactions occurring in the electrode assembly, and the movement of ions (e.g., lithium ions) may be involved depending on the electrochemical reaction.

[0004] According to the prior art, there was a possibility of lithium precipitation occurring as resistance increased due to separation between the electrodes and the separators. If lithium precipitation proceeded continuously, it could lead to problems with the safety and durability of the secondary battery. The problem to be solved

[0005] The problem that the present invention aims to solve is to provide an electrode assembly that improves the safety and durability of a secondary battery by effectively suppressing delamination between electrodes and separators, and a secondary battery including said electrode assembly. means of solving the problem

[0006] In an electrode assembly according to one embodiment of the present invention, the electrode assembly is provided by alternately stacking electrodes and separators in a predetermined stacking direction, wherein the electrode located at the outermost position among the electrodes is defined as the outermost electrode, and the separator located outside the outermost electrode among the separators is defined as the outermost separator, the end portion of the outermost separator may be provided to press the end portion of the outermost electrode inward in the stacking direction.

[0007] A secondary battery according to one embodiment of the present invention comprises an electrode assembly and a case that surrounds the electrode assembly and forms an outer periphery, wherein the electrode assembly is provided such that electrodes and separators are alternately stacked in a predetermined stacking direction, and when the electrode located at the outermost position among the electrodes is defined as the outermost electrode and the separator located outside the outermost electrode among the separators is defined as the outermost separator, the end portion of the outermost separator may be provided to press the end portion of the outermost electrode toward the inside of the stacking direction. Effects of the invention

[0008] According to a preferred embodiment of the present invention, lifting between electrodes and separators can be effectively suppressed.

[0009] According to a preferred embodiment of the present invention, the safety and durability of a secondary battery can be improved. Brief explanation of the drawing

[0010] FIG. 1 is a plan view showing a secondary battery according to an embodiment of the present invention. FIG. 2 is a top view of an electrode assembly according to an embodiment of the present invention. FIG. 3 is a side view showing a longitudinal section of an electrode assembly according to an embodiment of the present invention. FIG. 4 is a side cross-sectional view showing a longitudinal cross-section of an electrode assembly according to a first embodiment of the present invention. FIG. 5 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a first embodiment of the present invention. FIG. 6 is a side cross-sectional view showing a longitudinal section of an electrode assembly according to a second embodiment of the present invention. FIG. 7 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a second embodiment of the present invention. FIG. 8 is a side cross-sectional view showing a longitudinal section of an electrode assembly according to a third embodiment of the present invention. FIG. 9 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a third embodiment of the present invention. FIG. 10 is a side cross-sectional view showing a longitudinal section of an electrode assembly according to a fourth embodiment of the present invention. FIG. 11 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a fourth embodiment of the present invention. Specific details for implementing the invention

[0011] 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.

[0012] 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.

[0013] 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.

[0014] FIG. 1 is a plan view showing a secondary battery (1) according to an embodiment of the present invention, FIG. 2 is a plan view showing an electrode assembly (10) according to an embodiment of the present invention viewed from above, and FIG. 3 is a side view showing a longitudinal section of an electrode assembly (10) according to an embodiment of the present invention.

[0015] Referring to FIG. 1, the secondary battery (1) may include an electrode assembly (10). For example, the electrode assembly (10) may be provided by alternately stacking electrodes and separators in a predetermined stacking direction.

[0016] The secondary battery (1) may include electrode leads (e.g., 11, 12). For example, the first electrode lead (11) and the second electrode lead (12) may be electrically connected to the electrode assembly (10). Each of the first electrode lead (11) and the second electrode lead (12) may be electrically connected to the electrodes (e.g., negative electrodes, positive electrodes) of the electrode assembly (10), and may be connected to electrodes having different polarities.

[0017] The secondary battery (1) may include a case (20). For example, the case (20) may be provided to surround the electrode assembly (10). Additionally, the case (20) may form the outer perimeter of the secondary battery (1). As another example, the first electrode lead (11) and the second electrode lead (12) may each protrude outside the case (20). The first electrode lead (11) and the second electrode lead (12) may protrude outside to electrically connect the outside of the secondary battery (1) with the electrode assembly (10).

[0018] The case (20) may include a sealing portion (21). For example, the sealing portion (21) may be formed at the edge of the case (20). The sealing portion (21) may prevent communication between the inside and outside of the secondary battery (1). As another example, the first electrode lead (11) and the second electrode lead (12) may protrude to the outside by penetrating the sealing portion (21).

[0019] Referring to FIG. 2, the electrode assembly (10) may include electrode tabs (e.g., 101, 102). For example, the first electrode tab (101) and the second electrode tab (102) may be electrically connected to the electrode assembly (10). Each of the first electrode tab (101) and the second electrode tab (102) may be electrically connected to electrodes (e.g., negative electrodes, positive electrodes) of the electrode assembly (10), and may be connected to electrodes having different polarities. As another example, each of the first electrode tab (101) and the second electrode tab (102) may be electrically connected to the first electrode lead (11) and the second electrode lead (12). In other words, the first electrode lead (11) and the second electrode lead (12) can each be electrically connected to the electrode assembly (10) through the first electrode tab (101) and the second electrode tab (102).

[0020] Referring to FIG. 3, the electrode assembly (10) may be in a stacked form. The electrode assembly (10) may be formed by alternately stacking electrodes and separators along the stacking direction.

[0021] The electrodes may include first electrodes (120-1) and second electrodes (120-2). For example, the first electrodes (120-1) may be electrodes connected to a first electrode tab (101) that protrudes in a predetermined first direction. The second electrodes (120-2) may be connected to a second electrode tab (102) that protrudes in a second direction that is different from the first direction (e.g., opposite direction) and may have opposite polarity to the first electrodes.

[0022] The electrodes may include an outermost electrode (121). For example, the electrode located furthest outward among the electrodes may be defined as the outermost electrode (121). As another example, the outermost electrode (121) may be one of the first electrodes (120-1).

[0023] The separators may include an outermost separator (111). For example, a separator located outside the outermost electrode (121) among the separators may be defined as the outermost separator (111).

[0024] The end portion (111-1) of the outermost separator (111) may be the end portion on the second direction in which the second electrode tab (102) protrudes from the outermost separator (111).

[0025] The separators may include a stacked separator (112). For example, a separator positioned below the outermost electrode (121) among the separators may be defined as a stacked separator (112). Alternatively, the outermost electrode (121) may be positioned between the outermost separator (111) and the stacked separator (112).

[0026] The electrode assembly (10) may include inner separators (110). For example, the inner separators (110) may refer to separators other than the outermost separator (111) and the stacked separator (112) among the separators. As another example, the inner separators (110) may be separators stacked on an inner electrode (120) which is an electrode other than the outermost electrode (121) among the electrodes, but not stacked on the outermost electrode (121).

[0027] The electrode assembly (10) may include inner electrodes (120). For example, the inner electrodes (120) may refer to electrodes other than the outermost electrode (121) among the first electrodes (120-1) and the second electrodes (120-2).

[0028] The terms mentioned above are examples for the convenience of explanation and must not be understood as being limited to those terms.

[0029] FIG. 4 is a side cross-sectional view showing a longitudinal cross-sectional view of an electrode assembly (10) according to a first embodiment of the present invention, and FIG. 5 is a side cross-sectional view showing a longitudinal cross-sectional view of a secondary battery (1) according to a first embodiment of the present invention. The above-described longitudinal cross-sections may be longitudinal cross-sectional views along the A-A' line of FIG. 2. The above-described descriptions may be applied to the present embodiment in the same or similar manner.

[0030] Referring to FIG. 4, the electrode assembly (10) may include a pressurizing member (200). For example, the pressurizing member (200) may be positioned to cover at least the end portion (111-1) of the outermost separator (111) on the outside of the outermost separator (111). Additionally, the pressurizing member (200) may be positioned to cover an area other than the end portion (111-1) of the outermost separator (111).

[0031] The pressing member (200) may be configured to press the end portion (111-1) of the outermost separator (111) inwardly in the stacking direction. For example, the inner side in the stacking direction may be the direction from the outermost separator (111) toward the inner separator (110). Specifically, the pressing member (200) may press the end portion (111-1) of the outermost separator (111) inwardly in the stacking direction to press the end portion of the outermost electrode (121) inwardly in the stacking direction. Alternatively, the end portion (111-1) of the outermost separator (111) may be pressed by the pressing member (200) to press the end portion of the outermost electrode (121) inwardly in the stacking direction.

[0032] The pressure member (200) may protrude in a second direction. For example, the pressure member (200) may be laminated on the outer side of the outermost separator (111) and protrude in a second direction, thereby pressing the end portion of the outermost separator (111) and the end portion of the outermost electrode (121) inwardly in the lamination direction. By applying pressure with the pressure member (200), the lifting of the outermost separator (111) and the outermost electrode (121) is suppressed, and the contact force may be improved.

[0033] The pressure member (200) may include a metal member. For example, the metal member may include the same material as the second electrode tab (102). If the pressure member (200) includes the same metal material as the second electrode tab (102), the connection between the pressure member (200) and the second electrode tab (102) may be easy.

[0034] The end of the pressure member (200) can be coupled to the second electrode tab (102). For example, the pressure member (200) may be extended in a second direction, and its end may be coupled to at least the end of the second electrode tab (102). By being coupled to and fixed to the second electrode tab (102), the pressure member (200) can maintain the pressure state of the outermost separator (111).

[0035] Referring to FIG. 5, the pressurizing member (200) may be positioned between the case (20) and the outermost separator (111). For example, the pressurizing member (200) may be positioned between the inner surface of the case (20) and the outermost separator (111), and may cover at least the end portion of the outermost separator (111).

[0036] The inner surface of the case (20) may be configured to press the pressing member (200). For example, the inner surface of the case (20) presses the pressing member (200), and the pressing member (200) presses the outermost separator (111), thereby further suppressing the lifting of the outermost separator (111) and the outermost electrode (121), so that the contact force can be maximized. Accordingly, the safety and durability of the secondary battery (1) including the electrode assembly (10) can be improved.

[0037] FIG. 6 is a side cross-sectional view showing a longitudinal cross-sectional view of an electrode assembly (10a) according to a second embodiment of the present invention, and FIG. 7 is a side cross-sectional view showing a longitudinal cross-sectional view of a secondary battery (1a) according to a second embodiment of the present invention. The above-described longitudinal cross-sections may be longitudinal cross-sectional views along the A-A' line of FIG. 2. The above-described descriptions may be applied to the present embodiment in the same or similar manner.

[0038] Referring to FIG. 6, the pressure member (200a) may include an insulating member. For example, the pressure member (200a) may include an insulating member and extend in a second direction so as to form an overlapping area with the second electrode tab (102a) when viewed in the stacking direction. The pressure member (200a) may be positioned so as to form an overlapping area with the second electrode tab (102a) between the second electrode tab (102a) and the case (20), thereby insulating the second electrode tab (102a) and the case (20).

[0039] Referring to FIG. 7, the movement of the pressurizing member (200a) may be restricted by the case (20a). For example, the pressurizing member (200a) may be in contact with the inner surface of the case (20a) and its movement may be restricted by the frictional force with the inner surface. When the movement of the pressurizing member (200a) is restricted, the pressurization of the outermost separator (111) of the pressurizing member (200a) can be effectively maintained.

[0040] The pressurizing member (200a) can press the outermost separator (111a) by means of the case (20a). For example, the pressurizing member (200a) is pressed by the inner surface of the case (20a), and the pressurizing member (200a) can press the outermost separator (111a) inwardly in the stacking direction. Specifically, the pressurizing member (200a) can press at least the end portion (111-1a) of the outermost separator (111a) to suppress separation between the outermost separator (111) and the outermost electrode (121).

[0041] FIG. 8 is a side cross-sectional view showing a longitudinal cross-sectional view of an electrode assembly (10b) according to a third embodiment of the present invention, and FIG. 9 is a side cross-sectional view showing a longitudinal cross-sectional view of a secondary battery (1b) according to a third embodiment of the present invention. The above-described longitudinal cross-sections may be longitudinal cross-sectional views along the A-A' line of FIG. 2. The above-described descriptions may be applied to the present embodiment in the same or similar manner.

[0042] The electrode assembly (10b) may include a plurality of pressure members (e.g., 200-1b, 200-2b).

[0043] The electrode assembly (10b) may include a first pressure member (200-1b). The first pressure member (200-1b) may be laminated on the outside of the second pressure member (200-2b) described later. The first pressure member (200-1b) may include an insulating member.

[0044] The electrode assembly (10b) may include a second pressure member (200-2b). For example, the second pressure member (200-2b) may be placed on the outermost separator (111b). Specifically, the second pressure member (200-2b) may be laminated on the outside of the outermost separator (111b) to cover the end portion (111b-1b) of the outermost separator (111b). The second pressure member (200-2b) may include a metal member. Additionally, the second pressure member (200-2b) may be coupled with the second electrode tab (102b).

[0045] The first pressure member (200-1b) described above may correspond to the pressure member (200) of FIGS. 4 and FIGS. 5, and the second pressure member (200-2b) may correspond to the pressure member (200a) of FIGS. 6 and FIGS. 7.

[0046] The electrode assembly (10b) is provided with a plurality of pressure members (e.g., 200-1b, 200-2b), so that separation between the outermost separator (111b) and the outermost electrode (121b) can be effectively suppressed. For example, the first pressure member (200-1b) can press the second pressure member (200-2b) while insulating the second pressure member (200-2b) from the case (20b). Additionally, the second pressure member (200-2b) can be coupled to and fixed with the second electrode tab (102b). The second pressure member (200-2b) can press the outermost separator (111b) to suppress separation between the outermost separator (111b) and the outermost electrode (121b).

[0047] FIG. 10 is a side cross-sectional view showing a longitudinal cross-sectional view of an electrode assembly (10c) according to a fourth embodiment of the present invention, and FIG. 11 is a side cross-sectional view showing a longitudinal cross-sectional view of a secondary battery (1c) according to a fourth embodiment of the present invention. The above-described longitudinal cross-sections may be longitudinal cross-sectional views along the A-A' line of FIG. 2. The above-described descriptions may be applied to the present embodiment in the same or similar manner.

[0048] The separators of the electrode assembly (10c) can be bonded to each other. For example, the outermost separator (111c) and the stacked separator (112c) can be bonded to each other. Specifically, for example, the end (111-1c) of the outermost separator (111c) and the stacked separator (112c) (or the end of the stacked separator (112c)) can be bonded. As another specific example, the outermost separator (111c) and the inner separator (110c) (or the end portion of the inner separator (110c)) can be bonded.

[0049] Adhesion between the separators is not limited to the example described above, and can also be implemented with other combinations of adhesion that can pull the outermost separator (111c) inward in the stacking direction.

[0050] The separators of the electrode assembly (10c) are bonded to each other, so that the end portion (111-1c) of the outermost separator (111c) can be pulled inward in the stacking direction. Alternatively, the end portion (111-1c) of the outermost separator (111c) can be pulled inward in the stacking direction together with the end portion of the outermost electrode (121c). In this case, the end portion of the outermost electrode (121c) can be pressed by the end portion (111-1c) of the outermost separator (111c).

[0051] As described above, the separation between the outermost separator (111c) and the outermost electrode (121) can be suppressed through adhesion between the separators.

[0052] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0053] 1, 1a, 1b, 1c: Secondary battery 10, 10a, 10b, 10c: Electrode assembly 11: First electrode lead 12: Second electrode lead 20, 20a, 20b, 20c: Case 21, 21a, 21b, 21c: Sealing part 101, 101a, 101b, 101c: First electrode tab 102, 102a, 102b, 102c: Second electrode tab 110, 110a, 110b, 110c: Inner separator 111, 111a, 111b, 111c: Outermost membrane 111-1, 111-1a, 111-1b, 111-1c: Ends of the outermost membrane 112, 112a, 112b, 112c: Laminated separator 120, 120a, 120b, 120c: Inner electrodes 120-1, 120-1a, 120-1b, 120-1c: First electrode 120-2, 120-2a, 120-2b, 120-2c: Second electrode 121, 121a, 121b, 121c: Outermost electrodes 200, 200a: Pressurizing member 200-1b: First pressure member 200-2b: Second pressure member

Claims

Claim 1 An electrode assembly formed by alternately stacking electrodes and separators in a predetermined stacking direction, wherein the outermost electrode among the electrodes is defined as the outermost electrode, and the separator among the separators located outside the outermost electrode is defined as the outermost separator, wherein the end portion of the outermost separator is provided to press the end portion of the outermost electrode inward in the stacking direction, and further comprising a pressing member provided to cover at least the end portion of the outermost separator from the outside of the outermost separator and to press the end portion of the outermost separator inward in the stacking direction. Claim 2 An electrode assembly according to claim 1, wherein the end portion of the outermost separator is pressed inwardly in the stacking direction by the pressure member to the end portion of the outermost electrode. Claim 3 An electrode assembly according to claim 2, wherein the pressurizing member comprises: a metal member laminated on the outside of the outermost separator to cover the end portion of the outermost separator; and an insulating member laminated on the outside of the metal member. Claim 4 In an electrode assembly provided by alternately stacking electrodes and separators in a predetermined stacking direction, wherein the electrode located at the outermost position among the electrodes is defined as the outermost electrode, and the separator located outside the outermost electrode among the separators is defined as the outermost separator, the end portion of the outermost separator is provided to press the end portion of the outermost electrode inwardly toward the stacking direction, and the electrodes include first electrodes connected to a first electrode tab protruding in a predetermined first direction, and second electrodes connected to a second electrode tab protruding in a second direction different from the first direction, and having opposite polarity to the first electrodes, wherein the outermost electrode is one of the first electrodes, and the end portion of the outermost separator is the end portion on the second direction in which the second electrode tab protrudes among the outermost separator, and is stacked on the outside of the outermost separator and protrudes in the second direction, and the end portion of the outermost separator and the An electrode assembly further comprising a pressing member provided to press the end portion of the outermost electrode inward in the stacking direction. Claim 5 delete Claim 6 An electrode assembly according to claim 4, wherein the pressurizing member comprises a metal member extending in the second direction, the end of which is formed to be coupled to at least the end of the second electrode tab. Claim 7 In claim 6, the metal member is an electrode assembly formed of the same material as the second electrode tab. Claim 8 An electrode assembly according to claim 4, wherein the pressurizing member comprises an insulating member extending in the second direction such that an overlapping area with the second electrode tab is formed when viewed in the stacking direction. Claim 9 An electrode assembly according to claim 1, wherein the end portion of the outermost separator is coupled to the end portion of the inner separator, which is a separator laminated to an inner electrode that is an electrode other than the outermost electrode among the electrodes, and is not laminated to the outermost electrode, and is pulled inward in the lamination direction together with the end portion of the outermost electrode. Claim 10 A secondary battery comprising: an electrode assembly; and a case that surrounds the electrode assembly and forms an outer periphery, wherein the electrode assembly is provided such that electrodes and separators are alternately stacked in a predetermined stacking direction, wherein the electrode located at the outermost position among the electrodes is defined as the outermost electrode and the separator located outside the outermost electrode among the separators is defined as the outermost separator, and wherein the end portion of the outermost separator is provided to press the end portion of the outermost electrode inwardly in the stacking direction, and further comprising a pressing member disposed between the inner surface of the case and the outermost separator, at least covering the end portion of the outermost separator and provided to press the end portion of the outermost separator inwardly in the stacking direction. Claim 11 delete Claim 12 A secondary battery according to claim 10, wherein the pressurizing member is in contact with the inner surface and its movement is restricted by frictional force with the inner surface. Claim 13 In claim 10, the pressing member is a secondary battery that is pressed inward in the stacking direction by the inner surface.

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