Electrode assembly and battery including the same, and battery pack and automobile including the battery

Abstract

An electrode assembly according to one embodiment of the present invention has a structure in which a laminate in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked is wound up, and a support member configured to increase the rigidity of the inner wall of a winding center hole formed in a core portion of the electrode assembly by winding the laminate is provided on the inner wall.

Description

[Technical Field]

[0001] The present invention relates to an electrode assembly, a battery including the same, and a battery pack and a vehicle including the battery.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0187593 filed on December 28, 2022, and Korean Patent Application No. 10-2023-0193316 filed on December 27, 2023, and the contents disclosed in the specifications and drawings of those applications are incorporated herein in their entirety. [Background technology]

[0003] Secondary batteries, which have high applicability across a range of products and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electrical sources.

[0004] Such batteries have the primary advantage of significantly reducing the use of fossil fuels, as well as the advantage of not producing any by-products associated with energy use, and are therefore attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0005] Currently widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of such unit battery cells is approximately 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack may be constructed by connecting multiple battery cells in series. Furthermore, depending on the charge / discharge capacity required for the battery pack, a battery pack may be constructed by connecting multiple battery cells in parallel. Therefore, the number and electrical connection form of battery cells included in the battery pack may be variously set depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, a cylindrical battery may have a structure in which a jelly-roll type electrode assembly having a structure in which a negative electrode (positive electrode), a separator, a positive electrode (negative electrode), and a separator are sequentially stacked and wound up is housed in a substantially cylindrical battery housing.

[0007] A jelly roll-type electrode assembly used in such a cylindrical battery may have a central hole formed in a core portion by winding. As the battery is repeatedly charged and discharged, the electrodes constituting the electrode assembly may repeatedly expand and contract.

[0008] When the electrode expands and contracts repeatedly in this manner, a core collapse phenomenon may occur in which the electrode is partially bent on the inner wall surface of the winding center hole of the electrode assembly and protrudes toward the winding center hole. When this core collapse phenomenon occurs, there is an increased risk of a short circuit occurring in the core portion of the electrode assembly, which may make it difficult to ensure the safety of the secondary battery during use.

[0009] Therefore, there is a need for a method that can suppress deformation of the core structure of the electrode assembly caused by expansion and contraction of the electrodes due to repeated charging and discharging of the battery. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in consideration of the above problems, and aims to provide an electrode assembly having a structure that can suppress deformation of the core structure of the electrode assembly caused by expansion and contraction of the electrodes due to repeated charging and discharging of the battery.

[0011] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention given below. [Means for solving the problem]

[0012] According to one embodiment of the present invention for solving the above problems, there is provided an electrode assembly having a structure in which a laminate in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked is wound up, and a support member configured to increase the rigidity of the inner wall of a winding center hole formed in a core portion of the electrode assembly by winding up the laminate may be provided on the inner wall of the winding center hole.

[0013] The first separator may be positioned on an inner circumferential surface of the winding center hole.

[0014] The support may include a coating layer formed on at least one of the first separator and the second separator.

[0015] The coating layer may include an ultraviolet (UV) curing agent.

[0016] The coating layer may be formed on an inner surface of the first separator.

[0017] The support portion may extend at least a length corresponding to the circumference of the winding center hole in the circumferential direction.

[0018] The core portion of the electrode assembly may include a separator region in which the first separator and the second separator are wound up for at least one turn in a state in which the first separator and the second separator face each other directly, without the first electrode and the second electrode being interposed between the first separator and the second separator.

[0019] The coating layer may be formed within the separator region.

[0020] The supports may be arranged in a predetermined pattern.

[0021] The support portions may be arranged in a striped pattern.

[0022] Each band constituting the stripe pattern may extend in a direction inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the circumferential direction of the winding center hole.

[0023] A battery according to an embodiment of the present invention for solving the above-described problems may include an electrode assembly according to an embodiment of the present invention, and a battery housing configured to receive the electrode assembly.

[0024] A battery pack according to an embodiment of the present invention for solving the above-described problems may include a battery according to an embodiment of the present invention and a pack housing configured to accommodate the battery.

[0025] A vehicle according to an embodiment of the present invention for solving the above-described problems may include a battery pack according to an embodiment of the present invention. [Effects of the Invention]

[0026] According to one aspect of the present invention, it is possible to suppress deformation of the core structure of the electrode assembly caused by expansion and contraction of the electrodes due to repeated charging and discharging of the battery, thereby significantly improving the safety of the secondary battery in use.

[0027] However, the advantageous effects obtained by the present invention are not limited to the effects described above, and other advantageous effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical concepts of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view showing an electrode assembly according to an embodiment of the present invention; [Figure 2] 1 is a plan view illustrating an electrode assembly according to an embodiment of the present invention; [Figure 3] 5A to 5C are views illustrating a process of winding a laminate constituting an electrode assembly according to an embodiment of the present invention. [Figure 4] 1 is an enlarged view showing a region including a core portion of an electrode assembly according to an embodiment of the present invention (a view in which a support portion of the present invention is omitted); [Figure 5] 5 is a diagram illustrating a core collapse phenomenon that occurs when a battery including the electrode assembly shown in FIG. 4 is repeatedly charged and discharged. [Figure 6] FIG. 1 is a diagram showing a structure in which support portions are provided in a stripe pattern on a part of an electrode (first electrode or second electrode) of the present invention. [Figure 7] 1 illustrates a battery according to one embodiment of the present invention. [Figure 8] 1 illustrates a battery pack according to one embodiment of the present invention. [Figure 9] 1 illustrates a vehicle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, based on the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore, various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0031] First, an electrode assembly 10 according to one embodiment of the present invention will be described with reference to FIGS.

[0032] Fig. 1 is a perspective view showing an electrode assembly according to one embodiment of the present invention, and Fig. 2 is a plan view showing an electrode assembly according to one embodiment of the present invention. Fig. 3 is a view showing a process of winding a laminate constituting an electrode assembly according to one embodiment of the present invention, and Fig. 4 is an enlarged view showing a region including a core portion of an electrode assembly according to one embodiment of the present invention (the support portion of the present invention is omitted in this view). Fig. 5 is a view illustrating a core collapse phenomenon that occurs when a battery including the electrode assembly shown in Fig. 4 is repeatedly charged and discharged.

[0033] 1 to 4, an electrode assembly 10 according to an embodiment of the present invention may include a first electrode 11, a second electrode 12, a first separator 13, a second separator 14, and a support 15. The electrode assembly 10 may be, for example, a jelly-roll type electrode assembly. The electrode assembly 10 may have a structure in which a stack S, in which the first electrode 11, the first separator 13, the second electrode 12, and the second separator 14 are sequentially stacked, is wound in one direction.

[0034] The first electrode 11 may be a positive electrode or a negative electrode. The first electrode 11 may have a structure in which a first electrode active material is coated on one or both sides of a thin metal foil, for example. The second electrode 12 may be an electrode having the opposite polarity to the first electrode 11. The second electrode 12 may have a structure in which a second electrode active material is coated on one or both sides of a thin metal foil, for example. Although not specifically shown in the drawings for convenience of illustration, the first electrode 11 may include a first uncoated portion that is not coated with the first electrode active material, and similarly, the second electrode 12 may include a second uncoated portion that is not coated with the second electrode active material. When the first electrode 11 is a negative electrode and the second electrode 12 is a positive electrode, the area of the first electrode 11 may be larger than the area of the second electrode 12 in the laminate S.

[0035] The support portion 15 may be provided on the inner wall of a winding center hole 10a formed in the core portion of the electrode assembly 10 by winding the laminate S. The support portion 15 may be configured to increase the rigidity of the inner wall of the winding center hole 10a.

[0036] As described above, the electrode assembly 10 of the present invention is provided with the support portion 15 provided on the inner wall of the winding center hole 10a, thereby significantly reducing the risk of short circuiting due to core collapse in the core portion of the electrode assembly 10 caused by repeated charging and discharging of a battery including the electrode assembly 10.

[0037] Generally, when the electrodes constituting the electrode assembly 10 repeatedly expand and contract due to repeated charging and discharging of the battery, the end of the first electrode 11 may bend (flex) toward the core in the core portion of the electrode assembly 10, as shown in Fig. 5. Such bending (flexing) of the end of the first electrode 11 may cause damage to the first separator 13 constituting the inner wall surface of the winding center hole 10a, which may increase the risk of short circuits occurring in the area adjacent to the core portion of the electrode assembly 10. Therefore, by applying a structure that can improve the rigidity of the core portion of the electrode assembly 10, as in the present invention, it is possible to solve the problems associated with this core collapse phenomenon.

[0038] A first separator 13 may be located on the inner circumferential surface of the winding center hole 10a. In the laminate S, the first separator 13 may be interposed between the first electrode 11 and the second electrode 12. The second separator 14 may be provided on the outermost side of the laminate S. The first separator 13 may be located on the inner circumferential surface of the winding center hole 10a when the laminate S is wound in one direction. The second separator 14 may be configured to cover the outer circumferential surface of the electrode assembly 10 when the laminate S is wound in one direction.

[0039] The support part 15 may include a coating layer formed on at least one of the first separator 13 and the second separator 14. When the support part 15 is provided in the form of a coating on the first separator 13 and / or the second separator 14, a process such as inserting a separate part into a core part is not required, which is advantageous not only in terms of processability and productivity but also in terms of energy density.

[0040] When the support member 15 is provided in the form of a coating layer, the coating layer may contain an ultraviolet (UV) curing agent. In this case, the support member 15 is formed by applying an ultraviolet (UV) curing agent to the first separator 13 and / or the second separator 14 and then curing the agent by irradiating the agent with ultraviolet (UV) rays at a desired timing. The timing for curing the ultraviolet (UV) curing agent may be before or after the laminate S is wound up. The timing for performing the curing step may be determined taking into account the applied thickness and / or applied area of the ultraviolet (UV) curing agent. Even if the coating layer is in a cured state, if the first separator 13 and / or the second separator 14 can be easily wound up, it may be advantageous to perform the curing step before the laminate S is wound up. Conversely, when the coating layer is in a cured state, it is not easy to wind up the first separator 13 and / or the second separator 14, and if there is a concern that the first separator 13 and / or the second separator 14 may be damaged during winding, for example, it may be advantageous to perform the curing process after winding up the laminate S.

[0041] The coating layer may be formed on the inner surface of the first separator 13. In this case, the coating layer may be provided on the inner wall surface of the winding center hole 10a of the electrode assembly 10. Therefore, after the laminate S is wound, the coating layer can be cured by ultraviolet (UV) irradiation. That is, the coating layer can be exposed through the winding center hole 10a formed when the laminate S is wound, and accordingly, the coating layer can be cured by irradiating ultraviolet (UV) rays into the winding center hole 10a.

[0042] However, the position where the coating layer of the present invention is formed is not limited to this, and the coating layer may be formed on the inner surface of the first separator 13 and / or the outer surface of the first separator 13 and / or the inner surface of the second separator 14 and / or the outer surface of the second separator 14.

[0043] The support portion 15 may extend at least a length corresponding to the circumferential circumference of the winding center hole 10a. The support portion 15 may be configured to surround at least one circumference of the core portion of the electrode assembly 10. The support portion 15 may be configured to cover at least one circumference of the inner wall surface of the winding center hole 10a of the electrode assembly 10.

[0044] When the support portion 15 is configured in this manner, the rigidity of the entire periphery of the core portion of the electrode assembly 10 can be improved, thereby preventing or minimizing structural deformation of the core portion even when the battery is repeatedly charged and discharged. Suppressing structural deformation of the core portion in this manner can prevent, for example, the occurrence of micro-short circuits due to unwanted electrical contact in the core portion.

[0045] The core portion of the electrode assembly 10 may include a region (hereinafter referred to as the separator region) in which the first separator 13 and the second separator 14 are wound up for at least one turn, with the first separator 13 and the second separator 14 directly facing each other, without the first electrode 11 and the second electrode 12 being interposed between them.

[0046] Referring to Figures 3 and 4 together, when the first separator 13 and the second separator 14, which extend further outward than the longitudinal ends of the first electrode 11 and the second electrode 12, are held using a winding tool M and wound up in the direction of the arrow in Figure 3, there may be an area where only the first separator 13 and the second separator 14, excluding the first electrode 11 and the second electrode 12, are wound up in an overlapping state.

[0047] In this case, the separator region may be formed by covering the winding center hole 10a for at least one turn with the region where only the first separator 13 and the second separator 14 are stacked together, excluding the first electrode 11 and the second electrode 12. The support portion 15 may be provided in at least a portion of the separator region. When the support portion 15 is a coating layer formed on the first separator 13 and / or the second separator 14, the coating layer may be formed within the separator region.

[0048] The length D of the region where the support portion 15 is formed may be long enough to cover at least one circumference of the core portion. When the support portion 15 is formed to have a length long enough to cover at least one circumference of the core portion, the core portion of the electrode assembly 10 can be effectively strengthened.

[0049] Next, with reference to FIG. 6 in addition to FIGS. 1 to 3, a structure in which supporting portions 15 are provided in a stripe pattern on electrodes 11 and 12 of the present invention will be described.

[0050] FIG. 6 is a diagram showing a structure in which support portions are provided in a stripe pattern on a part of an electrode (first electrode or second electrode) of the present invention.

[0051] Referring to FIG. 6 in addition to FIGS. 1 to 3, the support members 15 of the present invention may be provided in a predetermined pattern. The support members 15 may be provided in, for example, a stripe pattern. When the support members 15 are provided in a predetermined pattern, it is possible to prevent the elasticity of the core portion of the electrode assembly 10 from being excessively suppressed. In this way, when the support members 15 are provided in a predetermined pattern, the elasticity of the first separator 13 and / or the second separator 14 is partially ensured, and it is possible to prevent stress caused by expansion and contraction of the electrode assembly 10 from being excessively accumulated in the core portion.

[0052] From another perspective, when the support members 15 are provided in a predetermined pattern, the formation of the support members 15 for strengthening the core portion of the electrode assembly 10 can minimize a decrease in the rate of electrolyte impregnation through the core portion. The first separator 13 and / or the second separator 14 may be porous. Therefore, the electrolyte may penetrate into the electrode assembly 10 through the inner wall of the winding center hole 10a of the electrode assembly 10 covered by the first separator 13 and / or the second separator 14. However, when the support members 15 are formed on at least one surface of the first separator 13 and / or the second separator 14, this may hinder the penetration of the electrolyte. Therefore, when the support members 15 are provided in a predetermined pattern on the inner wall of the winding center hole 10a, this effect on the electrolyte impregnation can be minimized.

[0053] When the support portions 15 are arranged in a striped pattern, each band constituting the striped pattern may extend in a direction inclined at a predetermined angle θ relative to the circumferential direction of the winding center hole 10a, i.e., the winding direction of the electrode assembly 10. The angle θ may be generally greater than 0 degrees and less than 90 degrees.

[0054] If each band constituting the stripe pattern extends in a direction substantially parallel to the winding direction of the electrode assembly 10, there will be no region in which the support portion 15 is omitted along the circumferential direction of the electrode assembly 10, which may make it difficult to partially ensure the elasticity of the first separator 13 and / or the second separator 14. Furthermore, if each band constituting the stripe pattern extends in a direction substantially perpendicular to the winding direction of the electrode assembly 10, there will be a section in which the support portion 15 is absent along the circumferential direction of the electrode assembly 10, which may make it difficult to effectively strengthen the first separator 13 and / or the second separator 14.

[0055] Next, referring to FIG. 7 in conjunction with FIG. 1, a battery 1 according to one embodiment of the present invention will be described.

[0056] FIG. 7 is a diagram illustrating a battery according to one embodiment of the present invention.

[0057] 7 in conjunction with Fig. 1, a battery 1 according to one embodiment of the present invention may include an electrode assembly 10 of the present invention and a battery housing 20 configured to house the electrode assembly 10. The battery 1 may be, for example, a cylindrical battery.

[0058] Next, a battery pack 3 according to an embodiment of the present invention will be described with reference to FIG.

[0059] FIG. 8 is a diagram illustrating a battery pack according to one embodiment of the present invention.

[0060] 8, a battery pack 3 according to an embodiment of the present invention may include the battery 1 of the present invention. The battery pack 3 may include an assembly of a plurality of electrically connected batteries 1 and a pack housing 2 that accommodates the assembly. For ease of illustration, components such as bus bars for electrically connecting the batteries 1, a cooling unit, and external terminals are omitted from the drawing.

[0061] Next, with reference to FIG. 9, a vehicle 5 according to an embodiment of the present invention will be described.

[0062] FIG. 9 is a diagram illustrating a vehicle according to one embodiment of the present invention.

[0063] 9, the automobile 5 may include the battery pack 3 of the present invention. The battery pack 3 may be mounted on the automobile 5. The automobile 5 of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile may include a four-wheeled vehicle or a two-wheeled vehicle. The automobile 5 may be configured to operate by receiving power from the battery pack 3 according to an embodiment of the present invention.

[0064] Although the present invention has been described above using limited embodiments and drawings, it goes without saying that the present invention is not limited to these, and that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the appended claims. [Explanation of symbols]

[0065] 1 battery 2-pack housing 3 Battery Pack 5. Automobiles 10 Electrode assembly 11 1st electrode 12 Second electrode 13 First separator 14 Second separator 15 Support part 20 Battery Housing M Winding tool S laminate

Claims

1. An electrode assembly having a structure in which a laminate in which a first electrode, a first separator, a second electrode, and a second separator are sequentially laminated is wound up, an electrode assembly, wherein a support portion configured to increase the rigidity of an inner wall of a winding center hole formed in a core portion of the electrode assembly by winding the laminate is provided on the inner wall of the winding center hole.

2. The electrode assembly according to claim 1 , wherein the first separator is located on an inner circumferential surface of the winding center hole.

3. The support portion is The electrode assembly of claim 2 , further comprising a coating layer formed on at least one of the first separator and the second separator.

4. The coating layer is The electrode assembly of claim 3 , further comprising an ultraviolet (UV) curing agent.

5. The coating layer is The electrode assembly according to claim 4 , wherein the first separator is formed on an inner surface thereof.

6. The support portion is 2. The electrode assembly of claim 1, wherein the electrode assembly extends at least a length corresponding to the circumferential circumference of the central winding hole.

7. The core portion of the electrode assembly is 4. The electrode assembly according to claim 3, comprising a separator region in which the first separator and the second separator are wound up for at least one turn in a state in which the first separator and the second separator directly face each other, without the first electrode and the second electrode being interposed between the first separator and the second separator.

8. The coating layer is The electrode assembly of claim 7 formed within the separator region.

9. The support portion is 10. The electrode assembly of claim 1, wherein the electrode assembly is provided in a predetermined pattern.

10. The support portion is 10. The electrode assembly of claim 9, arranged in a striped pattern.

11. Each stripe constituting the stripe pattern is The electrode assembly according to claim 10 , wherein the electrode extends in a direction inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the circumferential direction of the winding center hole.

12. An electrode assembly according to any one of claims 1 to 11; a battery housing configured to house the electrode assembly; Including the battery.

13. The battery of claim 12; a pack housing configured to house the battery; Including the battery pack.

14. A motor vehicle comprising the battery pack of claim 13.

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