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 in a state in which electrodes and separators are alternately stacked in a predetermined stacking direction. When an outermost electrode among the electrodes is defined as an outermost electrode and a separator among the separators positioned outward of the outermost electrode is defined as an outermost separator, an end portion of the outermost separator may be configured to press an end portion of the outermost electrode inward in the stacking direction.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0166012, dated December 1, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly and a secondary battery including the electrode assembly. [Background technology]

[0003] To solve the problem of environmental pollution caused by the excessive use of fossil fuels and the problem of energy shortages due to the depletion of fossil fuels, research and development into environmentally friendly energy-based power generation has been progressing. In recent years, research into rechargeable secondary batteries has been actively progressing, and various aspects of secondary batteries, such as their materials, structure, processes, stability, and durability, are being studied.

[0004] A secondary battery includes an electrode assembly therein, which may be formed by alternately stacking electrodes having different polarities and separators. The secondary battery produces electrical energy based on an electrochemical reaction that occurs in the electrode assembly, and the electrochemical reaction may involve the movement of ions (e.g., lithium ions).

[0005] In the prior art, lifting occurs between the electrode and the separator, which increases resistance and can lead to lithium precipitation. If lithium precipitation continues, it can cause problems in the safety and durability of the secondary battery. Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide an electrode assembly that effectively suppresses lift-up between an electrode and a separator, thereby improving the safety and durability of the secondary battery, and a secondary battery including the electrode assembly. [Means for solving the problem]

[0007] In an electrode assembly according to an embodiment of the present invention, the electrode assembly is provided by alternately stacking electrodes and separators in a predetermined stacking direction. When an outermost electrode among the electrodes is defined as an outermost electrode and a separator among the separators positioned outward of the outermost electrode is defined as an outermost separator, an end portion of the outermost separator may be configured to press an end portion of the outermost electrode inward in the stacking direction.

[0008] A secondary battery according to one embodiment of the present invention includes an electrode assembly and a case surrounding the electrode assembly to form an outer shell. The electrode assembly is provided with electrodes and separators alternately stacked in a predetermined stacking direction. When an outermost electrode among the electrodes is defined as an outermost electrode and a separator among the separators positioned outward of the outermost electrode is defined as an outermost separator, the electrode assembly may be configured such that an end portion of the outermost separator presses an end portion of the outermost electrode inward in the stacking direction. [Effects of the Invention]

[0009] According to a preferred embodiment of the present invention, lifting between the electrode and the separator can be effectively suppressed.

[0010] According to a preferred embodiment of the present invention, the safety and durability of a secondary battery can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view showing a secondary battery according to an embodiment of the present invention; [Figure 2]1 is a plan view showing the shape of an electrode assembly according to an embodiment of the present invention as viewed from above; [Figure 3] 1 is a side view showing a vertical cross section of an electrode assembly according to an embodiment of the present invention; [Figure 4] 1 is a side cross-sectional view showing a vertical cross section of an electrode assembly according to a first embodiment of the present invention. [Figure 5] 1 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a first embodiment of the present invention. [Figure 6] FIG. 6 is a side cross-sectional view showing a vertical cross section of an electrode assembly according to a second embodiment of the present invention. [Figure 7] FIG. 4 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a side cross-sectional view showing a vertical cross section of an electrode assembly according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a side cross-sectional view showing a vertical cross section of an electrode assembly according to a fourth embodiment of the present invention. [Figure 11] FIG. 10 is a side cross-sectional view showing a longitudinal section of a secondary battery according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand the preferred embodiments of the present invention. However, the present invention may be realized in various different forms and is not limited to the following embodiments.

[0013] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and in this specification, when adding reference symbols to components in each drawing, the same or similar reference symbols will be used throughout the specification to refer to the same or similar components.

[0014] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0015] 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 the shape of an electrode assembly 10 according to an embodiment of the present invention as viewed from above, and FIG. 3 is a side view showing a vertical cross section of the electrode assembly 10 according to an embodiment of the present invention.

[0016] 1, a secondary battery 1 may include an electrode assembly 10. For example, the electrode assembly 10 may be provided in a state in which electrodes and separators are alternately stacked in a predetermined stacking direction.

[0017] 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. The first electrode lead 11 and the second electrode lead 12 may be electrically connected to electrodes (e.g., negative and positive electrodes) of the electrode assembly 10, and may be connected to electrodes having different polarities.

[0018] The secondary battery 1 may include a case 20. For example, the case 20 may be provided to surround the electrode assembly 10. The case 20 may also form an outer shell of the secondary battery 1. As another example, the first electrode lead 11 and the second electrode lead 12 may each protrude to the outside of the case 20. The first electrode lead 11 and the second electrode lead 12 may protrude to the outside, thereby electrically connecting the outside of the secondary battery 1 and the electrode assembly 10.

[0019] The case 20 may include a sealing portion 21. For example, the sealing portion 21 may be formed on 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 penetrate the sealing portion 21 and protrude to the outside.

[0020] Referring to FIG. 2 , the electrode assembly 10 may include electrode tabs (e.g., 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. The first electrode tab 101 and the second electrode tab 102 may be electrically connected to electrodes (e.g., negative and positive electrodes) of the electrode assembly 10, respectively, and may be connected to electrodes having different polarities. As another 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, the first electrode lead 11 and the second electrode lead 12 may be electrically connected to the electrode assembly 10 via the first electrode tab 101 and the second electrode tab 102, respectively.

[0021] 3, the electrode assembly 10 may have a stacked structure. The electrode assembly 10 may be provided in a state in which electrodes and separators are alternately stacked in a stacking direction.

[0022] The electrodes may include a first electrode 120-1 and a second electrode 120-2. For example, the first electrode 120-1 may be connected to a first electrode tab 101 protruding in a predetermined first direction. The second electrode 120-2 may be connected to a second electrode tab 102 protruding in a second direction different from the first direction (e.g., opposite direction) and may have an opposite polarity to the first electrode.

[0023] The electrodes may include an outermost electrode 121. For example, the electrode located at the outermost side of 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.

[0024] The separator may include an outermost separator 111. For example, among the separators, a separator located outside the outermost electrode 121 may be defined as the outermost separator 111.

[0025] The end portion 111-1 of the outermost separator 111 may be an end portion of the outermost separator 111 in the second direction in which the second electrode tab 102 protrudes.

[0026] The separator may include a stacked separator 112. For example, among the separators, a separator disposed below the outermost electrode 121 may be defined as the stacked separator 112. In other words, the outermost electrode 121 may be disposed between the outermost separator 111 and the stacked separator 112.

[0027] The electrode assembly 10 may include an inner separator 110. For example, the inner separator 110 may refer to a separator other than the outermost separator 111 and the stacked separator 112. As another example, the inner separator 110 may be a separator that is stacked on an inner electrode 120, which is an electrode other than the outermost electrode 121, but is not stacked on the outermost electrode 121.

[0028] The electrode assembly 10 may include an inner electrode 120. For example, the inner electrode 120 may refer to an electrode other than the outermost electrode 121 among the first electrode 120-1 and the second electrode 120-2.

[0029] The above terms are merely examples for the convenience of explanation, and should not necessarily be construed as being limited to the above terms.

[0030] Fig. 4 is a side cross-sectional view showing a longitudinal section 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 section of a secondary battery 1 according to a first embodiment of the present invention. The above-mentioned longitudinal section is taken along line A-A' in Fig. 2. The above description can be applied equally or similarly to this embodiment.

[0031] 4, the electrode assembly 10 may include a pressure member 200. For example, the pressure member 200 may be disposed outside the outermost separator 111 so as to cover at least the end portion 111-1 of the outermost separator 111. The pressure member 200 may also be disposed so as to cover an area of ​​the outermost separator 111 other than the end portion 111-1.

[0032] The pressing member 200 can be provided to press the end portion 111-1 of the outermost separator 111 inward in the stacking direction. For example, the inward direction in the stacking direction can be the direction from the outermost separator 111 toward the inner separator 110. Specifically, the pressing member 200 can 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 is pressed by the pressing member 200, and the end portion of the outermost electrode 121 can be pressed inward in the stacking direction.

[0033] The pressing member 200 can protrude in the second direction. For example, the pressing member 200 can protrude in the second direction while stacked on the outside of the outermost separator 111, and press the end portions of the outermost separator 111 and the outermost electrode 121 inward in the stacking direction. The pressure applied by the pressing member 200 can prevent the outermost separator 111 and the outermost electrode 121 from lifting up, thereby improving the contact force.

[0034] 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 pressure member 200 and the second electrode tab 102 may be easily coupled to each other.

[0035] An end 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 an end thereof may be coupled to at least an end of the second electrode tab 102. The pressing member 200 may be coupled and fixed to the second electrode tab 102, thereby maintaining the outermost separator 111 in a compressed state.

[0036] 5, the pressure member 200 may be disposed between the case 20 and the outermost separator 111. For example, the pressure member 200 may be disposed between the inner surface of the case 20 and the outermost separator 111, and may cover at least an end portion of the outermost separator 111.

[0037] The inner surface of the case 20 may be configured to pressurize 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 lifting of the outermost separator 111 and the outermost electrode 121 and maximizing the contact force. This may improve the safety and durability of the secondary battery 1 including the electrode assembly 10.

[0038] 6 is a side cross-sectional view showing a longitudinal section 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 section of a secondary battery 1a according to a second embodiment of the present invention. The above-mentioned longitudinal section is taken along line A-A' in FIG. 2. The above description can be applied equally or similarly to this embodiment.

[0039] 6, the pressure member 200a may include an insulating member. For example, the pressure member 200a may include an insulating member and extend in the second direction so as to form an overlapping region with the second electrode tab 102a when viewed in the stacking direction. The pressure member 200a may be disposed so as to form an overlapping region between the second electrode tab 102a and the case 20a, thereby insulating the second electrode tab 102a from the case 20a.

[0040] 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 the movement may be restricted by friction with the inner surface. When the movement of the pressing member 200a is restricted, the pressing member 200a may effectively maintain pressure on the outermost separator 111.

[0041] The pressing member 200a can pressurize the outermost separator 111a by the case 20a. For example, the pressing member 200a is pressed by the inner surface of the case 20a, and the pressing member 200a can pressurize the outermost separator 111a inward in the stacking direction. Specifically, the pressing member 200a presses at least the end portion 111-1a of the outermost separator 111a, and can suppress lifting between the outermost separator 111a and the outermost electrode 121.

[0042] 8 is a side cross-sectional view showing a longitudinal section 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 section of a secondary battery 1b according to a third embodiment of the present invention. The above-mentioned longitudinal section is taken along line A-A' in FIG. 2. The above description can be applied equally or similarly to this embodiment.

[0043] The electrode assembly 10b may include multiple pressure members (eg, 200-1b, 200-2b).

[0044] The electrode assembly 10b may include a first pressure member 200-1b. The first pressure member 200-1b may be stacked on the outside of a second pressure member 200-2b (described later). The first pressure member 200-1b may include an insulating member.

[0045] The electrode assembly 10b may include a second pressure member 200-2b. For example, the second pressure member 200-2b may be disposed on the outermost separator 111b. Specifically, the second pressure member 200-2b may be laminated on the outer side 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. In addition, the second pressure member 200-2b may be coupled to the second electrode tab 102b.

[0046] The above-mentioned first pressure member 200-1b may correspond to the pressure member 200 in FIGS. 4 and 5, and the second pressure member 200-2b may correspond to the pressure member 200a in FIGS.

[0047] The electrode assembly 10b includes a plurality of pressure members (e.g., 200-1b, 200-2b), which can effectively prevent the outermost separator 111b and the outermost electrode 121b from lifting up. For example, the first pressure member 200-1b can insulate the second pressure member 200-2b from the case 20b and pressurize the second pressure member 200-2b. The second pressure member 200-2b can be coupled to and fixed to the second electrode tab 102b. The second pressure member 200-2b pressurizes the outermost separator 111b, thereby preventing the outermost separator 111b and the outermost electrode 121b from lifting up.

[0048] 10 is a side cross-sectional view showing a vertical section 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 vertical section of a secondary battery 1c according to a fourth embodiment of the present invention. The above-mentioned vertical section is taken along line A-A' in FIG. 2. The above description can be applied equally or similarly to this embodiment.

[0049] The separators of the electrode assembly 10c may be bonded to each other. For example, the outermost separator 111c and the stacked separator 112c may be bonded to each other. Specifically, for example, the end 111-1c of the outermost separator 111c may be bonded to the stacked separator 112c (or the end of the stacked separator 112c). As another specific example, the outermost separator 111c may be bonded to the inner separator 110c (or the end portion of the inner separator 110c).

[0050] The bonding between the separators is not limited to the above example, and other bonding combinations that can pull the outermost separator 111c inward in the stacking direction can also be used.

[0051] The separators of the electrode assembly 10c are bonded to each other, and the end portion 111-1c of the outermost separator 111c can be pulled 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 111-1c of the outermost separator 111c can apply pressure to the end portion of the outermost electrode 121c.

[0052] As described above, the adhesion between the separators can prevent the outermost separator 111c and the outermost electrode 121 from lifting up.

[0053] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various modifications can be made by a person skilled in the art within the scope of the appended claims and the technical concept of the present invention. [Explanation of symbols]

[0054] 1, 1a, 1b, 1c secondary battery 10, 10a, 10b, 10c electrode assembly 11 First electrode lead 12 Second electrode lead 20, 20a, 20b, 20c cases 21, 21a, 21b, 21c seal parts 101, 101a, 101b, 101c First electrode tab 102, 102a, 102b, 102c Second electrode tabs 110, 110a, 110b, 110c inner separator 111, 111a, 111b, 111c outermost separator 111-1, 111-1a, 111-1b, 111-1c End portions of outermost separators 112, 112a, 112b, 112c laminated separator 120, 120a, 120b, 120c inner electrode 120-1, 120-1a, 120-1b, 120-1c 1st electrode 120-2, 120-2a, 120-2b, 120-2c 2nd electrode 121, 121a, 121b, 121c outermost electrode 200, 200a pressure member 200-1b First pressure member 200-2b Second pressure member

Claims

1. An electrode assembly in which electrodes and separators are alternately stacked in a predetermined stacking direction, When the electrode positioned at the outermost side among the electrodes is defined as an outermost electrode, and the separator positioned at the outer side of the outermost electrode among the separators is defined as an outermost separator, An electrode assembly, wherein an end portion of the outermost separator is arranged to press an end portion of the outermost electrode inward in the stacking direction.

2. a pressure member provided outside the outermost separator to cover at least an end portion of the outermost separator and to press the end portion of the outermost separator inward in the stacking direction, The electrode assembly according to claim 1 , wherein the end portion of the outermost separator presses the end portion of the outermost electrode inward in the stacking direction by the pressing member.

3. The pressure member is a metal member laminated on the outside of the outermost separator so as to cover an end portion of the outermost separator; an insulating member laminated on the outside of the metal member; The electrode assembly of claim 2 , comprising:

4. the electrodes include 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 having an opposite polarity to the first electrode; the outermost electrode is one of the first electrodes, The electrode assembly according to claim 1 , wherein the end portion of the outermost separator is an end portion of the outermost separator in the second direction from which the second electrode tab protrudes.

5. 5. The electrode assembly according to claim 4, further comprising a pressure member that is stacked on the outside of the outermost separator, protrudes in the second direction, and applies pressure inwardly to an end portion of the outermost separator and an end portion of the outermost electrode in the stacking direction.

6. The electrode assembly of claim 5 , wherein the pressure member comprises a metal member extending in the second direction, the metal member having an end coupled to at least an end of the second electrode tab.

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

8. The electrode assembly of claim 5 , wherein the pressure member includes an insulating member extending in the second direction so as to form an overlapping region overlapping the second electrode tab when viewed from the stacking direction.

9. 9. The electrode assembly according to claim 1, wherein an end portion of the outermost separator is bonded to an end portion of an inner separator that is a separator stacked on an inner electrode that is an electrode other than the outermost electrode among the electrodes and that is not stacked on the outermost electrode, and is pulled inward in the stacking direction together with the end portion of the outermost electrode and is pressurized.

10. an electrode assembly; a case surrounding the electrode assembly to form an outer shell; A secondary battery comprising: The electrode assembly is A secondary battery in which electrodes and separators are alternately stacked in a predetermined stacking direction, and when the electrode located outermost among the electrodes is defined as the outermost electrode and the separator located outward of the outermost electrode is defined as the outermost separator, the secondary battery is arranged such that an end portion of the outermost separator presses an end portion of the outermost electrode inward in the stacking direction.

11. 11. The secondary battery according to claim 10, further comprising a pressure member disposed between the inner surface of the case and the outermost separator, covering at least an end portion of the outermost separator, and applying pressure to the end portion of the outermost separator inward in the stacking direction.

12. The secondary battery according to claim 11 , wherein the pressure member is in contact with the inner surface and movement thereof is restricted by frictional force between the pressure member and the inner surface.

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

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