Electrode assemblies and batteries containing them, as well as battery packs and automobiles containing those batteries.

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, a battery pack including the battery, and a vehicle.

[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 all the contents disclosed in the specifications and drawings of the applications are incorporated into this application.

Background Art

[0003] Secondary batteries, which are highly adaptable to a variety of products and have electrical characteristics such as a high energy density, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by an electric drive source.

[0004] Such batteries have not only the primary advantage of significantly reducing the use of fossil fuels but also the advantage of generating no by-products associated with energy use, and thus are attracting attention as a new energy source for environmental friendliness and improved energy efficiency.

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

[0006] On the other hand, a cylindrical battery may have a structure in which a jelly roll-type electrode assembly, which has a structure in which a laminate of a negative electrode (positive electrode), separator, positive electrode (negative electrode), separator is wound up, is housed in a substantially cylindrical battery housing.

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

[0008] When electrodes repeatedly expand and contract in this manner, a core collapse phenomenon may occur where the electrodes are partially bent on the inner wall surface of the winding center hole of the electrode assembly and protrude towards the winding center hole. If such a core collapse phenomenon occurs, the risk of a short circuit in the core of the electrode assembly increases, which may make it difficult to ensure the safety of the secondary battery during use.

[0009] Therefore, there is a need for measures that can suppress the deformation of the core structure of the electrode assembly caused by the expansion and contraction of electrodes that occur due to repeated charging and discharging of the battery. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention has been made in view 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 the expansion and contraction of electrodes that occur due to repeated charging and discharging of the battery.

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

[0012] An electrode assembly according to one embodiment of the present invention for solving the above problems is 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 portion configured to increase the rigidity of the inner wall may be provided on the inner wall of the winding center hole formed in the core portion of the electrode assembly by winding up the laminate.

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

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

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

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

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

[0018] The core portion of the electrode assembly may include a separator region that is wound at least once in a state where the first separator and the second separator face each other directly, without the first electrode and the second electrode intervening between the first separator and the second separator.

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

[0020] The support portion may be provided in a predetermined pattern.

[0021] The support portion may be provided in a stripe pattern (striped pattern).

[0022] Each band constituting the stripe pattern may extend along a direction inclined at an angle of more 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 accommodate 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] An automobile 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.

Advantages of the Invention

[0026] According to one aspect of the present invention, it is possible to suppress deformation of the structure of the core portion of the electrode assembly caused by expansion and contraction of the electrodes generated by repeated charge and discharge of the battery, thereby greatly improving the safety in using the secondary battery.

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

[0028] The drawings attached to this specification illustrate the preferred embodiments of the present invention and are for the purpose of further understanding the technical idea of the present invention together with the content of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0029] [Figure 1] It is a perspective view showing an electrode assembly according to an embodiment of the present invention. [Figure 2] It is a plan view showing an electrode assembly according to an embodiment of the present invention. [Figure 3] It is a diagram showing a process of winding a laminate constituting an electrode assembly according to an embodiment of the present invention. [Figure 4] It 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 the support portion of the present invention is omitted). [Figure 5] It is a diagram for explaining a core collapse phenomenon generated when a battery including the electrode assembly shown in FIG. 4 repeatedly charges and discharges. [Figure 6] It is a diagram showing a structure in which a support portion is provided in a stripe pattern on a part of an electrode (first electrode or second electrode) of the present invention. [Figure 7] It is a diagram showing a battery according to an embodiment of the present invention. [Figure 8] It is a diagram showing a battery pack according to an embodiment of the present invention. [Figure 9] It is a diagram showing an automobile according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0030] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims are not to be interpreted in a manner limited to their usual or dictionary meanings, but rather in a manner corresponding to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concept of terms in order to best describe the invention. Accordingly, the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that there are various equivalents and modifications that can be substituted thereat the time of this application.

[0031] First, an electrode assembly 10 according to one embodiment of the present invention will be described with reference to Figures 1 to 5.

[0032] Figure 1 is a perspective view showing an electrode assembly according to one embodiment of the present invention, and Figure 2 is a plan view showing an electrode assembly according to one embodiment of the present invention. Figure 3 is a diagram showing the process of winding up the laminate constituting the electrode assembly according to one embodiment of the present invention, and Figure 4 is an enlarged view showing the region including the core portion of the electrode assembly according to one embodiment of the present invention (a diagram in which the support portion of the present invention is omitted). Figure 5 is a diagram for explaining the core collapse phenomenon that occurs when a battery including the electrode assembly shown in Figure 4 undergoes repeated charging and discharging.

[0033] First, referring to Figures 1 to 4, an electrode assembly 10 according to one 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 portion 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 laminate 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 or 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. For convenience of illustration, although not specifically shown in the drawings of the present invention, the first electrode 11 may include a first plain area that is not coated with the first electrode active material, and similarly, the second electrode 12 may include a second plain area 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 formed to 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 the winding central 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 central hole 10a.

[0036] As described above, the electrode assembly 10 of the present invention includes a support portion 15 provided on the inner wall of the winding central hole 10a, thereby significantly reducing the risk of short circuits occurring due to core collapse in the core portion of the electrode assembly 10 caused by repeated charging and discharging of the 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, a phenomenon may occur in the core portion of the electrode assembly 10 where the end of the first electrode 11 bends (bends) toward the core, as shown in Figure 5. Such bending (bending) of the end of the first electrode 11 can cause damage to the first separator 13 that constitutes the inner wall surface of the winding center hole 10a, which may increase the risk of a short circuit occurring in the region 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, the problems associated with such core collapse can be solved.

[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 part of the laminate S. When the laminate S is wound in one direction, 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.

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

[0040] If the support portion 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 portion 15 is cured by applying the ultraviolet (UV) curing agent to the first separator 13 and / or the second separator 14, and then irradiating it with ultraviolet (UV) light at a desired timing. The timing of curing the ultraviolet (UV) curing agent may be after or before winding the laminate S. The timing of the curing process can be determined by considering the coating thickness and / or coating area of ​​the ultraviolet (UV) curing agent. If the first separator 13 and / or the second separator 14 can be easily wound up even when the coating layer is cured, it may be advantageous to perform the curing process before winding up the laminate S. Conversely, when the coating layer is hardened, winding the first separator 13 and / or the second separator 14 is not easy. If there is concern about damage to the first separator 13 and / or the second separator 14 during winding, it may be advantageous to perform the hardening process after winding the laminate S.

[0041] The coating layer can be formed on the inner surface of the first separator 13. In this case, the coating layer can be provided on the inner wall surface of the winding center hole 10a of the electrode assembly 10. Therefore, after winding the laminate S, 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 the winding center hole 10a with ultraviolet (UV) light.

[0042] However, the formation location of the coating layer of the present invention 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 to a length corresponding to the circumference of the winding center hole 10a. The support portion 15 may be configured to surround the core portion of the electrode assembly 10 at least once. The support portion 15 may be configured to cover the inner wall surface of the winding center hole 10a of the electrode assembly 10 at least once.

[0044] With the support portion 15 configured in this way, the overall rigidity around the core portion of the electrode assembly 10 can be improved, thereby preventing or minimizing deformation of the core structure even when the battery is repeatedly charged and discharged. By suppressing deformation of the core structure in this way, for example, the occurrence of micro-shorts (tiny short circuits) due to unnecessary electrical contact in the core can be prevented.

[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 at least one turn while facing each other directly, without the first electrode 11 and the second electrode 12 being interposed between them.

[0046] Referring together to Figures 3 and 4, 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 in the direction of the arrow in Figure 3, there may be a region in which only the first separator 13 and the second separator 14 are wound up overlapping each other, excluding the first electrode 11 and the second electrode 12.

[0047] In this case, excluding the first electrode 11 and the second electrode 12, the region in which only the first separator 13 and the second separator 14 overlap each other can form the separator region by covering the winding center hole 10a at least once. The support portion 15 may be provided in at least a part of the separator region. If 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 such that it covers the core portion at least once. When the support portion 15 is formed to a length that covers the core portion at least once, the core portion of the electrode assembly 10 can be effectively reinforced.

[0049] Next, referring to Figures 1 to 3 and Figure 6, the structure of the present invention in which the support portion 15 is provided in a stripe pattern on the electrodes 11 and 12 will be described.

[0050] Figure 6 shows a structure in which a support portion is provided in a stripe pattern on a part of the electrode (first electrode or second electrode) of the present invention.

[0051] Referring to Figure 6 in conjunction with Figures 1 to 3, the support portion 15 of the present invention can be provided in a predetermined pattern. The support portion 15 can be provided in, for example, a stripe pattern. When the support portion 15 is provided in a predetermined pattern, it is possible to prevent the phenomenon in which the elasticity of the core portion of the electrode assembly 10 is excessively suppressed. In this way, by providing the support portion 15 in a predetermined pattern, the elasticity of the first separator 13 and / or the second separator 14 is partially ensured, which prevents excessive stress accumulation in the core portion due to the expansion and contraction of the electrode assembly 10.

[0052] From another perspective, if the support portion 15 is provided in a predetermined pattern, the formation of the support portion 15 to reinforce the core portion of the electrode assembly 10 can minimize the phenomenon of a decrease in the impregnation rate of the electrolyte passing through the core portion. The first separator 13 and / or the second separator 14 may be porous. Therefore, the electrolyte can penetrate into the interior of 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, if the support portion 15 is formed on at least one surface of the first separator 13 and / or the second separator 14, it may hinder such penetration of the electrolyte. Therefore, if the support portion 15 is provided in a predetermined pattern on the inner wall of the winding center hole 10a, the effect on such electrolyte impregnation can be minimized.

[0053] When the support portion 15 is provided in a stripe pattern, each strip constituting the stripe pattern may extend along the circumferential direction of the winding center hole 10a, that is, in a direction inclined at a predetermined angle θ with respect to 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 of the stripes constituting the stripe pattern extends along a direction substantially parallel to the winding direction of the electrode assembly 10, there is no region along the circumferential direction of the electrode assembly 10 where the support portion 15 is omitted, which may make it difficult to partially ensure the elasticity of the first separator 13 and / or the second separator 14. Also, if each of the stripes constituting the stripe pattern extends along a direction substantially perpendicular to the winding direction of the electrode assembly 10, sections where the support portion 15 is partially absent are formed along the circumferential direction of the electrode assembly 10, which may make it difficult to effectively reinforce the first separator 13 and / or the second separator 14.

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

[0056] Figure 7 shows a battery according to one embodiment of the present invention.

[0057] Referring to Figure 7 in conjunction with Figure 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, with reference to Figure 8, a battery pack 3 according to one embodiment of the present invention will be described.

[0059] Figure 8 shows a battery pack according to one embodiment of the present invention.

[0060] Referring to Figure 8, a battery pack 3 according to an embodiment of the present invention may include a battery 1 of the present invention. The battery pack 3 may include an assembly of multiple batteries 1 electrically connected, and a pack housing 2 that houses them. For convenience of illustration, the drawings omit the depiction of components such as busbars for electrical connection between the batteries 1, cooling units, and external terminals.

[0061] Next, with reference to Figure 9, an automobile 5 according to one embodiment of the present invention will be described.

[0062] Figure 9 shows an automobile according to one embodiment of the present invention.

[0063] Referring to Figure 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, for example, be 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 one embodiment of the present invention.

[0064] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations can be made by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the appended claims. [Explanation of symbols]

[0065] 1 Battery 2-pack housing 3 Battery Packs 5. Automobile 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 is wound up in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked, The inner wall of the winding center hole formed in the core of the electrode assembly by winding the laminate is provided with a support portion configured to increase the rigidity of the inner wall. The first separator is located on the inner circumferential surface of the winding center hole. The aforementioned support portion is The coating layer is formed on at least one of the first separator and the second separator. The aforementioned coating layer is An electrode assembly formed on the inner surface of the first separator.

2. The aforementioned coating layer is The electrode assembly according to claim 1, comprising an ultraviolet (UV) curing agent.

3. The aforementioned support portion is The electrode assembly according to claim 1, which extends by a length corresponding to at least the circumference of the winding central hole in the circumferential direction.

4. An electrode assembly having a structure in which a laminate is wound up in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked, The inner wall of the winding center hole formed in the core of the electrode assembly by winding the laminate is provided with a support portion configured to increase the rigidity of the inner wall. The first separator is located on the inner circumferential surface of the winding center hole. The aforementioned support portion is The coating layer is formed on at least one of the first separator and the second separator. The core portion of the electrode assembly is An electrode assembly comprising a separator region wound at least one turn with the first separator and the second separator facing each other directly, without the first electrode and the second electrode being interposed between the first separator and the second separator.

5. The aforementioned coating layer is The electrode assembly according to claim 4, formed within the separator region.

6. An electrode assembly having a structure in which a laminate is wound up in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked, The inner wall of the winding center hole formed in the core of the electrode assembly by winding the laminate is provided with a support portion configured to increase the rigidity of the inner wall. The aforementioned support portion is An electrode assembly arranged in a predetermined pattern.

7. The aforementioned support portion is The electrode assembly according to claim 6, provided in a stripe pattern.

8. Each of the bands constituting the aforementioned stripe pattern is The electrode assembly according to claim 7, wherein it extends along a direction inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the circumferential direction of the winding central hole.

9. An electrode assembly according to any one of claims 1 to 8, A battery housing configured to house the electrode assembly, Includes a battery.

10. The battery according to claim 9, A pack housing configured to house the aforementioned battery, A battery pack, including the battery pack.

11. An automobile comprising the battery pack described in claim 10.

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