Electrode assembly and secondary battery including the same

Abstract

An electrode assembly according to an embodiment of the present invention may be provided by alternately stacking electrodes and separators in a given stacking direction, in which when an electrode placed at an outermost position among the electrodes is defined as an outermost electrode and a separator placed at an outer side of the outermost electrode among the separators is defined as an outermost separator, the electrode and the separator are alternately stacked in a given stacking direction. An end portion of the outermost separator may be disposed to press an end portion of the outermost electrode inward in a stacking direction.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0166012, filed on December 1, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to an electrode assembly and a secondary battery including the electrode assembly. Background Art

[0004] To solve environmental pollution problems caused by the excessive use of fossil fuels and energy problems caused by the depletion of fossil fuels, research and development of power generation based on eco-friendly energy are underway. Recently, research on rechargeable secondary batteries has been actively conducted, and various aspects of secondary batteries, such as materials, structures, processes, stability, and durability, are being studied.

[0005] A secondary battery has an electrode assembly, and the electrode assembly can be formed by alternately stacking electrodes and separators having different polarities. The secondary battery generates electrical energy based on an electrochemical reaction occurring in the electrode assembly, and the electrochemical reaction can involve the movement of ions (e.g., lithium ions).

[0006] According to the related art, as excitation occurs between the electrode and the separator, lithium precipitation may occur as the resistance increases. When lithium precipitation continues, problems may arise in the safety and durability of the secondary battery. Summary of the Invention

[0007] Technical Problem

[0008] An object of the present invention for solving the above problems is to provide an electrode assembly and a secondary battery including the electrode assembly, in which delamination between the electrode and the separator is effectively suppressed to improve the safety and durability of the secondary battery.

[0009] Technical Solution

[0010] An electrode assembly according to an embodiment of the present invention can be provided by alternately stacking electrodes and separators in a predetermined stacking direction, wherein when the outermost electrode among the electrodes is defined as the outermost electrode and the outermost separator among the separators is defined as the outermost separator, the end portion of the outermost separator may be set to inwardly press the end portion of the outermost electrode in the stacking direction.

[0011] A secondary battery according to an embodiment of the present invention may include: an electrode assembly; and a case configured to surround the electrode assembly to define an outer portion of the electrode assembly, wherein the electrode assembly may be arranged such that electrodes and separators are alternately stacked in a predetermined stacking direction, and when the outermost electrode among the electrodes is defined as the outermost electrode and the outermost separator among the separators is defined as the outermost separator, an end portion of the outermost separator may be arranged to press an end portion of the outermost electrode inward in the stacking direction.

[0012] Advantageous Effects

[0013] According to a preferred embodiment of the present invention, delamination between the electrodes and the separators can be effectively suppressed.

[0014] According to a preferred embodiment of the present invention, the safety and durability of the secondary battery can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a plan view of a secondary battery according to an embodiment of the present invention.

[0016] Figure 2 is a plan view showing the structure of the electrode assembly when viewed from above according to an embodiment of the present invention.

[0017] Figure 3 is a side view showing a longitudinal section of the electrode assembly according to an embodiment of the present invention.

[0018] Figure 4 is a side sectional view showing a longitudinal section of the electrode assembly according to a first embodiment of the present invention.

[0019] Figure 5 is a side sectional view showing a longitudinal section of the secondary battery according to a first embodiment of the present invention.

[0020] Figure 6 is a side sectional view showing a longitudinal section of the electrode assembly according to a second embodiment of the present invention.

[0021] Figure 7 is a side sectional view showing a longitudinal section of the secondary battery according to a second embodiment of the present invention.

[0022] Figure 8 is a side sectional view showing a longitudinal section of the electrode assembly according to a third embodiment of the present invention.

[0023] Figure 9 is a side sectional view showing a longitudinal section of the secondary battery according to a third embodiment of the present invention.

[0024] Figure 10It is a side sectional view showing a longitudinal section of an electrode assembly according to a fourth embodiment of the present invention.

[0025] Figure 11 It is a side sectional view showing a longitudinal section of a secondary battery according to a fourth embodiment of the present invention. Detailed Description of the Invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention. However, the present invention can be implemented in several different forms and is not limited or restricted by the following examples.

[0027] To clearly explain the present invention, descriptions or detailed descriptions of parts irrelevant to the points of the present invention that may unnecessarily obscure the present invention or related known technologies are omitted, and reference numerals are added to the components in each drawing in this specification. In this case, throughout the specification, the same or similar reference numerals are assigned to the same or similar elements.

[0028] Furthermore, the terms or words used in this specification and claims should not be construed restrictively as ordinary meanings or dictionary-based meanings, but should be construed as meanings and concepts that conform to the scope of the present invention based on the concept that the inventor can appropriately define the terms in order to best describe and explain the principles of his or her invention.

[0029] Figure 1 It is a plan view of a secondary battery 1 according to an embodiment of the present invention, Figure 2 It is a plan view showing the structure of an electrode assembly 10 when viewed from above according to an embodiment of the present invention, and Figure 3 It is a side view showing a longitudinal section of an electrode assembly 10 according to an embodiment of the present invention.

[0030] When referring to Figure 1 the description, the secondary battery 1 may include an electrode assembly 10. For example, the electrode assembly 10 may be prepared by alternately stacking electrodes and separators along a predetermined stacking direction.

[0031] The secondary battery 1 may include electrode leads (e.g., reference numerals 11 and 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 an electrode (e.g., a negative electrode and a positive electrode) of the electrode assembly 10, that is, electrodes having different polarities.

[0032] The secondary battery 1 may include a case 20. For example, the case 20 may be arranged to surround the electrode assembly 10. In addition, the case 20 may define the appearance of the secondary battery 1. For example, each of the first electrode lead 11 and the second electrode lead 12 may protrude to the outside of the case 20. The first electrode lead 11 and the second electrode lead 12 protrude to the outside to electrically connect the outside of the secondary battery 1 to the electrode assembly 10.

[0033] The case 20 may include a sealing part 21. For example, the sealing part 21 may be placed on the edge of the case 20. The sealing part 21 may inhibit communication between the inside and the outside of the secondary battery 1. Again, for example, the first electrode lead 11 and the second electrode lead 12 may pass through the sealing part 21 to protrude to the outside.

[0034] When referring to Figure 2 description, the electrode assembly 10 may include electrode tabs (e.g., reference numerals 101 and 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 an electrode (e.g., a negative electrode and a positive electrode) of the electrode assembly 10, that is, electrodes with different polarities. Again, for example, 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, respectively. In other words, each of the first electrode lead 11 and the second electrode lead 12 may be electrically connected to the electrode assembly 10 through the first electrode tab 101 and the second electrode tab 102, respectively.

[0035] When referring to Figure 3 description, the electrode assembly 10 may be in a stacked form. The electrode assembly 10 may be prepared by alternately stacking electrodes and separators in a stacking direction.

[0036] The electrodes may include a first electrode 120-1 and a second electrode 120-2. For example, the first electrode 120-1 may be an electrode connected to the first electrode tab 101 protruding in a predetermined first direction. The second electrode 120-2 may be connected to the second electrode tab 102 protruding in a second direction (e.g., the opposite direction) different from the first direction and have a polarity opposite to that of the first electrode.

[0037] The electrodes may include an outermost electrode 121. For example, the electrode placed on the outermost side of the electrodes may be defined as the outermost electrode 121. Again, for example, the outermost electrode 121 may be one of the first electrodes 120-1.

[0038] The separator may include an outermost separator 111. For example, among the separators, the separator placed outside the outermost electrode 121 may be defined as the outermost separator 111.

[0039] The end portion 111-1 of the outermost separator 111 may be the end portion of the outermost separator 111 in the second direction in which the second electrode tab 102 protrudes.

[0040] The separator may include a stacked separator 112. For example, among the separators, the separator placed below the outermost electrode 121 may be defined as the stacked separator 112. In other words, the outermost electrode 121 may be placed between the outermost separator 111 and the stacked separator 112.

[0041] The electrode assembly 10 may include an inner separator 110. For example, the inner separator 110 may refer to the separator among the separators other than the outermost separator 111 and the stacked separator 112. Another example is that the inner separator 110 may be a separator stacked on the inner electrode 120 but not on the outermost electrode 121, and the inner electrode 120 is the electrode among the electrodes other than the outermost electrode 121.

[0042] The electrode assembly 10 may include an inner electrode 120. For example, the inner electrode 120 may refer to the electrode among the first electrode 120-1 and the second electrode 120-2 other than the outermost electrode 121.

[0043] For ease of explanation, the above terms are examples, and the understanding does not have to be limited to the above terms.

[0044] Figure 4 is a side sectional view showing a longitudinal section of an electrode assembly according to a first embodiment of the present invention, and Figure 5 is a side sectional view showing a longitudinal section of a secondary battery according to a first embodiment of the present invention. The above longitudinal section may be a longitudinal section taken along the Figure 2 line A-A' in. The above description can also be equivalently or similarly applied to this embodiment.

[0045] Referring to Figure 4 , the electrode assembly 10 may include a pressing member 200. For example, the pressing member 200 may be placed on the outside of the outermost separator 111 to cover at least the end portion 111-1 of the outermost separator 111. In addition, the pressing member 200 may be placed to cover the area of the outermost separator 111 other than the end portion 111-1.

[0046] The pressing member 200 may be configured to press the end portion 111-1 of the outermost separator 111 inward in the stacking direction. For example, the inner side in the stacking direction may be the direction from the outermost separator 111 to the inner separator 110. Specifically, the pressing member 200 may press the end portion 111-1 of the outermost separator 111 inward in the stacking direction and press the end portion of the outermost electrode 121 inward in the stacking direction. In other words, 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 inward in the stacking direction.

[0047] The pressing member 200 may protrude in a second direction. For example, the pressing member 200 may be stacked outside the outermost separator 111 to protrude in the second direction, thereby pressing the end portion of the outermost separator 111 and the end portion of the outermost electrode 121 inward in the stacking direction. Delamination of the outermost separator 111 and the outermost electrode 121 may be suppressed due to the pressing of the pressing member 200 to improve the contact force.

[0048] The pressing member 200 may include a metal member. For example, the metal member may include the same material as the second electrode tab 102. When the pressing member 200 includes the same metal material as the second electrode tab 102, the pressing member 200 and the second electrode tab 102 may be easily coupled to each other.

[0049] An end portion of the pressing member 200 may be coupled to the second electrode tab 102. For example, the pressing member 200 may extend in the second direction, and the end portion may be coupled to at least the end portion of the second electrode tab 102. The pressing member 200 may be coupled and fixed to the second electrode tab 102 to maintain the pressed state of the outermost separator 111.

[0050] Referring to Figure 5 , the pressing member 200 may be disposed between the housing 20 and the outermost separator 111. For example, the pressing member 200 may be disposed between the inner surface of the housing 20 and the outermost separator 111 and cover at least the end portion of the outermost separator 111.

[0051] The inner surface of the housing 20 may be configured to press the pressing member 200. For example, the inner surface of the housing 20 may press the pressing member 200, and the pressing member 200 may press the outermost separator 111 to further suppress delamination of the outermost separator 111 and the outermost electrode 121, thereby maximizing the contact force. Accordingly, the safety and durability of the secondary battery 1 including the electrode assembly 10 may be improved.

[0052] Figure 6 is a side cross-sectional view showing a longitudinal cross-section of an electrode assembly according to a second embodiment of the present invention, and Figure 7 is a side cross-sectional view showing a longitudinal cross-section of a secondary battery according to a second embodiment of the present invention. The above longitudinal cross-section may be a longitudinal cross-section taken along the Figure 2 line A-A' in

[0053] Reference Figure 6 , the pressing member 200a may include an insulating member. For example, the pressing member 200a may include an insulating member and may extend in a second direction to provide an overlapping area overlapping with the second electrode tab 102a when viewed in the stacking direction. The pressing member 200a may be disposed to provide an overlapping area with the second electrode tab 102a between the second electrode tab 102a and the case 20a, thereby insulating the second electrode tab 102a from the case 20a.

[0054] Referring to Figure 7 , the movement of the pressing member 200a may be restricted by the case 20a. For example, the pressing member 200a may contact the inner surface of the case 20a and may restrict movement by the frictional force with the inner surface. When the movement of the pressing member 200a is restricted, the pressing of the pressing member 200a on the outermost separator 111 can be effectively maintained.

[0055] The pressing member 200a may press the outermost separator 111a through the case 20a. For example, the pressing member 200a may be pressed by the inner surface of the case 20a, and the pressing member 200a may press the outermost separator 111a inward in the stacking direction. Specifically, the pressing member 200a may press at least the end portion 111-1a of the outermost separator 111a to inhibit delamination between the outermost separator 111 and the outermost electrode 121.

[0056] Figure 8 is a side cross-sectional view showing a longitudinal cross-section of an electrode assembly according to a third embodiment of the present invention, Figure 9 is a side cross-sectional view showing a longitudinal cross-section of a secondary battery according to a third embodiment of the present invention. The above longitudinal cross-section may be a longitudinal cross-section taken along the Figure 2 line A-A' in

[0057] The electrode assembly 10b may include a plurality of pressing members (e.g., 200-1b, 200-2b).

[0058] The electrode assembly 10b may include a first pressing member 200-1b. The first pressing member 200-1b may be stacked outside the second pressing member 200-2b, which will be described later. The first pressing member 200-1b may include an insulating member.

[0059] The electrode assembly 10b may include a second pressing member 200-2b. For example, the second pressing member 200-2b may be placed on the outermost separator 111b. Specifically, the second pressing member 200-2b may be stacked outside the outermost separator 111b to cover the end portion 111b-1b of the outermost separator 111b. The second pressing member 200-2b may include a metal member. In addition, the second pressing member 200-2b may be coupled to the second electrode tab 102b.

[0060] The above-mentioned first pressing member 200-1b may correspond to Figure 4 and Figure 5 the pressing member 200, and the second pressing member 200-2b may correspond to Figure 6 and Figure 7 the pressing member 200a.

[0061] The electrode assembly 10b may be provided with a plurality of pressing members (e.g., 200-1b and 200-2b) to effectively suppress delamination between the outermost separator 111b and the outermost electrode 121b. For example, the first pressing member 200-1b may press the second pressing member 200-2b while insulating the second pressing member 200-2b from the housing 20b. In addition, the second pressing member 200-2b may be coupled and fixed to the second electrode tab 102b. The second pressing member 200-2b may press the outermost separator 111b to suppress delamination between the outermost separator 111b and the outermost electrode 121b.

[0062] Figure 10 is a side sectional view showing a longitudinal section of an electrode assembly according to a fourth embodiment of the present invention, Figure 11 is a side sectional view showing a longitudinal section of a secondary battery according to a fourth embodiment of the present invention. The above-mentioned longitudinal section may be a longitudinal section taken along the Figure 2 A-A' line in

[0063] The separators of the electrode assembly 10c can be joined to each other. For example, the outermost separator 111c and the stacked separators 112c can be joined 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 joined to each other. For another specific example, the outermost separator 111c and the inner separator 110c (or the end portion of the inner separator 110c) can be joined to each other.

[0064] The joining between the separators is not limited to the above examples, and can also be achieved by other combinations of joining that can pull the outermost separator 111c inward in the stacking direction.

[0065] The separators of the electrode assembly 10c can be joined to each other to pull the end portion 111-1c of the outermost separator 111c inward in the stacking direction. In other words, 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.

[0066] As described above, delamination between the outermost separator 111c and the outermost electrode 121 can be suppressed by the joining between the separators.

[0067] Although embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention as defined in the appended claims.

[0068] [Description of Reference Numerals]

[0069] 1, 1a, 1b, 1c: Secondary battery

[0070] 10, 10a, 10b, 10c: Electrode assembly

[0071] 11: First electrode lead

[0072] 12: Second electrode lead

[0073] 20, 20a, 20b, 20c: Case

[0074] 21, 21a, 21b, 21c: Sealing portion

[0075] 101, 101a, 101b, 101c: First electrode tab

[0076] 102, 102a, 102b, 102c: Second electrode tab

[0077] 110, 110a, 110b, 110c: Inner partition members

[0078] 111, 111a, 111b, 111c: Outermost partition members

[0079] 111-1, 111-1a, 111-1b, 111-1c: End portions of the outermost partition members

[0080] 112, 112a, 112b, 112c: Stacking partition members

[0081] 120, 120a, 120b, 120c: Inner electrodes

[0082] 120-1, 120-1a, 120-1b, 120-1c: First electrodes

[0083] 120-2, 120-2a, 120-2b, 120-2c: Second electrodes

[0084] 121, 121a, 121b, 121c: Outermost electrodes

[0085] 200, 200a: Pressing members

[0086] 200-1b: First pressing member

[0087] 200-2b: Second pressing member

Claims

1. An electrode assembly in which electrodes and separators are alternately stacked along a predetermined stacking direction. Wherein, When the outermost electrode among the electrodes is defined as the outermost electrode and the outermost separator among the separators is defined as the outermost separator, The end portion of the outermost separator is arranged to inwardly press the end portion of the outermost electrode along the stacking direction.

2. The electrode assembly according to claim 1, further comprising a pressing member, the pressing member being arranged to press at least the end portion of the outermost separator at the outside of the outermost separator and to inwardly press the end portion of the outermost separator in the stacking direction, Wherein, The end portion of the outermost separator is configured to inwardly press the end portion of the outermost electrode in the stacking direction by the pressing member.

3. The electrode assembly according to claim 2, Wherein, The pressing member includes: A metal member stacked on the outside of the outermost separator to cover the end portion of the outermost separator; and An insulating member stacked on the outside of the metal member.

4. The electrode assembly according to claim 1, wherein the electrode Comprises: A first electrode connected to a first electrode tab protruding in a predetermined first direction; And A second electrode connected to a second electrode tab protruding in a second direction different from the first direction, and each of the second electrodes has a polarity opposite to that of each of 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 of the outermost separator in the second direction in which the second electrode tab protrudes.

5. The electrode assembly according to claim 4, further comprising a pressing member stacked on the outside of the outermost separator to protrude in the second direction and arranged to inwardly press the end portion of the outermost separator and the end portion of the outermost electrode in the stacking direction.

6. The electrode assembly according to claim 5, Wherein, The pressing member includes a metal member extending in the second direction and arranged such that the end of the metal member is coupled to the end of the second electrode tab.

7. The electrode assembly according to claim 6, wherein the metal member is made of the same material as the second electrode tab.

8. The electrode assembly according to claim 5, Wherein, The pressing member includes an insulating member extending in the second direction to provide an overlapping region overlapping with the second electrode tab when viewed in the stacking direction.

9. The electrode assembly according to claim 1, Wherein, The end portion of the outermost separator is coupled to the end portion of the inner separator, so that the end portion of the outermost separator is squeezed to be pulled inward together with the end portion of the outermost electrode in the stacking direction, and the inner separator is a separator not stacked on the outermost electrode.

10. A secondary battery comprising: an electrode assembly; and a case configured to surround the electrode assembly to define an outer portion of the electrode assembly, wherein the electrode assembly is arranged such that electrodes and separators are alternately stacked in a predetermined stacking direction, and when the electrode placed at the outermost side among the electrodes is defined as the outermost electrode, and the separator placed at the outermost side among the separators is defined as the outermost separator, the end portion of the outermost separator is arranged to squeeze the end portion of the outermost electrode inward in the stacking direction.

11. The secondary battery according to claim 10, further comprising a pressing member placed between the inner surface of the case and the outermost separator, configured to cover at least the end portion of the outermost separator, and arranged to squeeze the end portion of the outermost separator inward in the stacking direction.

12. The secondary battery according to claim 11, wherein the pressing member contacts the inner surface and is restricted from moving by the frictional force with the inner surface.

13. The secondary battery according to claim 11, wherein the pressing member is squeezed inward in the stacking direction by the inner surface.

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