Electrode assembly, cylindrical lithium-sulfur battery cell comprising same, and battery pack and vehicle comprising cylindrical lithium-sulfur battery cell

Abstract

Disclosed are an electrode assembly, a cylindrical lithium-sulfur battery cell including the electrode assembly, and a battery pack and a vehicle including the cylindrical lithium-sulfur battery cell. An electrode assembly according to an embodiment of the present disclosure is a jelly-roll type electrode assembly having a structure in which a cathode plate, an anode plate, and a separator interposed between the cathode plate and the anode plate are wound in one direction and have a center hole, the jelly-roll type electrode assembly including a center pin, the center pin is inserted into the center hole and presses the electrode assembly.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2022-0177618 filed on December 16, 2022 and Korean Patent Application No. 10-2023-0038899 filed on March 24, 2023, the disclosures of which are incorporated herein by reference.

[0002] The present disclosure relates to an electrode assembly and a cylindrical lithium-sulfur battery cell including the electrode assembly, and a battery pack and a vehicle including the cylindrical lithium-sulfur battery cell, and more particularly, to an electrode assembly capable of squeezing the center of the electrode assembly and a cylindrical lithium-sulfur battery cell including the electrode assembly, and a battery pack and a vehicle including the cylindrical lithium-sulfur battery cell. Background Art

[0003] As application fields of secondary batteries expand to electric vehicles (EVs) or energy storage systems (ESSs), lithium-ion secondary batteries having a relatively low energy storage density (~250 Wh / kg) relative to weight have limited applications to these products.

[0004] In contrast, lithium-sulfur secondary batteries have attracted much attention as the next generation secondary battery technology because they can theoretically achieve high energy storage density relative to weight (~2600Wh / kg).

[0005] Lithium-sulfur secondary batteries are battery systems that use sulfur-based materials with sulfur-sulfur bonds as positive electrode active materials and lithium metal as negative electrode active materials. Lithium-sulfur secondary batteries have the following advantages: sulfur (the main material of the positive electrode active material) is globally abundant, non-toxic, and has a low weight per atom.

[0006] In lithium-sulfur secondary batteries, during discharge, lithium as the negative electrode active material ionizes electrons and is oxidized, and the sulfur-based material as the positive electrode active material receives electrons and is reduced. At this time, the oxidation reaction of lithium is a process in which lithium metal donates electrons and is converted into a lithium cation form.

[0007] In addition, the sulfur reduction reaction is a process in which the sulfur-sulfur bond receives two electrons and is converted into a sulfur anion form. The lithium cations generated by the lithium oxidation reaction are transferred to the positive electrode through the electrolyte and combined with the sulfur anions generated by the sulfur reduction reaction to form a salt.

[0008] Specifically, before discharge, sulfur has a cyclic S 8 structure, which is converted into lithium polysulfide (Li 2 S x , x = 8, 6, 4, 2), and when this lithium polysulfide is completely reduced, lithium sulfide (Li 2 S).

[0009] In order for the lithium-sulfur secondary battery to operate and exhibit appropriate electrochemical performance, an appropriate level of pressure should be applied to the electrode assembly during operation.

[0010] For example, when lithium metal is used as a negative electrode active material in a lithium-sulfur secondary battery, if charging and discharging are repeated in this state, the thickness of the lithium metal itself increases due to uneven plating and peeling of the lithium metal.

[0011] In this case, due to the increase in the specific surface area of ​​lithium metal, a side reaction with the electrolyte may be triggered, the battery performance may be deteriorated due to dead Li, etc., and in addition, an internal short circuit may occur due to the growth of lithium metal dendrites.

[0012] Therefore, various problems associated with using lithium metal as a negative electrode active material can be solved by compressing the electrode assembly. Here, when the lithium-sulfur secondary battery is manufactured in a pouch type, pressure applied from the outside can be transmitted to the electrode assembly.

[0013] However, when a lithium-sulfur secondary battery is designed in a jelly-roll type cylindrical shape and a cylindrical metal can is used as a battery case, pressure cannot be applied to the electrode assembly during operation of the secondary battery, which causes the above-mentioned various problems, making it difficult to operate the battery normally. Summary of the invention

[0014] Technical issues

[0015] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure aims to provide a jelly-roll type electrode assembly, and more particularly, an electrode assembly that applies pressure to a central hole.

[0016] The present disclosure also aims to provide a cylindrical lithium-sulfur battery cell including an electrode assembly having an improved structure, and a battery pack and a vehicle including the cylindrical lithium-sulfur battery cell.

[0017] The technical problems to be solved by the present disclosure are not limited to the above-mentioned problems, and those skilled in the art can clearly understand other problems not mentioned herein based on the following description of the present disclosure.

[0018] Technical Solution

[0019] According to one aspect of the present disclosure, a jelly-roll type electrode assembly is provided, the electrode assembly having a structure in which a positive electrode plate, a negative electrode plate, and a separator between the positive electrode plate and the negative electrode plate are wound in one direction, and the electrode assembly has a center hole formed therein, the electrode assembly including a center pin that is inserted into the center hole to compress the electrode assembly.

[0020] In one embodiment, the center pin may include: a core portion inserted into the center hole, having an opening formed therein and varying in diameter size in at least a portion thereof; and an insert portion inserted into the opening of the core portion to adjust the size of the diameter of the core portion.

[0021] In one embodiment, the core may include a support portion located on an upper side and having an opening formed therein; a connecting portion connected to the support portion; and an expansion portion connected to the connecting portion, the expansion portion expanding on both sides through the insertion portion and pressing the electrode assembly in a centrifugal direction.

[0022] In one embodiment, the expansion portion may include a plurality of units, a preset space may be formed between the plurality of units, and the insertion portion inserted from the opening may be inserted through the space.

[0023] In one embodiment, the expansion portion may include a first unit and a second unit, each of the first unit and the second unit may have at least one protrusion and at least one groove, and the protrusions and grooves of the first unit and the grooves and protrusions of the second unit may be alternately positioned to correspond to each other.

[0024] In an embodiment, a portion of the protrusion of the first unit may be configured to engage with a portion of the groove of the second unit, and a portion of the groove of the first unit may be configured to engage with a portion of the protrusion of the second unit.

[0025] In an embodiment, the protrusion and the groove of the first unit may have a curvature within a preset range, and the protrusion and the groove of the second unit may also have a curvature within a preset range.

[0026] In an embodiment, the protrusion and the groove of the first unit may have a circular shape, and the protrusion and the groove of the second unit may also have a circular shape.

[0027] In an embodiment, before the insertion part is inserted, the expansion part may be formed in a shape in which its diameter decreases from the top to the bottom.

[0028] In an embodiment, the diameter of the connecting portion may be configured to be smaller than the diameter of the supporting portion and also smaller than the diameter of the expanding portion.

[0029] In an embodiment, the connection portion may be coupled to the center of the support portion, and the support portion may have a wide width in the vertical direction at the center where the connection portion is coupled, and have a narrowed width in the vertical direction from the center to both ends.

[0030] In an embodiment, the insert may include a head portion and a shaft portion extending from the head portion.

[0031] Meanwhile, according to another aspect of the present disclosure, a cylindrical lithium-sulfur battery cell is provided, which includes: the above-mentioned electrode assembly; a cylindrical battery can, in which the electrode assembly is accommodated; a positive current collector, which is electrically connected to the positive electrode plate; a cell terminal, which is connected to the positive current collector through a through hole of the battery can; and a negative current collector, which is electrically connected to the negative electrode plate.

[0032] Meanwhile, according to another aspect of the present disclosure, a battery pack including the above cylindrical lithium-sulfur battery cell and a vehicle including the cylindrical lithium-sulfur battery cell are provided.

[0033] Beneficial effects

[0034] The center pin according to the present disclosure is inserted into the center hole of the jelly-roll type electrode assembly to compress the electrode assembly, thereby having the effect of maximizing the expression of electrochemical performance when applied to a cylindrical lithium-sulfur battery cell.

[0035] It also has the effects of reducing the side reaction of the electrolyte, preventing the degradation of the monomer performance caused by dead lithium and the like, and preventing the internal short circuit.

[0036] Furthermore, the present disclosure may have various other effects, which will be described in each embodiment, or description of effects that can be easily inferred by those skilled in the art will be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure, and thus the present disclosure is not to be construed as being limited to the accompanying drawings.

[0038] Figure 1 is a schematic cross-sectional view of a cylindrical lithium-sulfur battery cell according to an embodiment of the present disclosure, wherein a center pin is separated from an electrode assembly.

[0039] Figure 2 is a cross-sectional view of a core of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure.

[0040] Figure 3 is a plan view of a core of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure.

[0041] Figure 4 is a perspective view of an insertion portion of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure.

[0042] Figure 5 is a cross-sectional view showing that an insertion portion according to an embodiment of the present disclosure is inserted into a core portion of a center pin inserted into a center hole of an electrode assembly.

[0043] Figure 6 is a plan view showing that an insertion portion according to an embodiment of the present disclosure is inserted into a core portion of a center pin inserted into a center hole of an electrode assembly.

[0044] Figure 7 is a schematic cross-sectional view showing a core portion of a center pin coupled to an electrode assembly in a cylindrical lithium-sulfur battery cell according to an embodiment of the present disclosure.

[0045] Figure 8 The insertion portion is shown inserted into Figure 7 A schematic cross-sectional view of a core in which the core is pressed against an electrode assembly by an insert.

[0046] Fig. 9 yes Figure 2 Another embodiment of .

[0047] Fig.10 yes Figure 5 Another embodiment of .

[0048] Fig.11 is a view schematically showing a configuration of a battery pack according to an embodiment of the present disclosure.

[0049] Fig.12 It is used to describe Fig.11 View of the battery pack of a vehicle. DETAILED DESCRIPTION

[0050] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but are interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that the inventors are allowed to appropriately define the terms for the best interpretation.

[0051] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes, and are not intended to limit the scope of the present disclosure, and it should be appreciated that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0052] In addition, to help understand the present disclosure, the accompanying drawings are not drawn to actual scale, but the sizes of some components may be exaggerated. In addition, in different embodiments, the same reference numerals may be assigned to the same components.

[0053] The terms used herein are for the purpose of describing exemplary embodiments only and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, a singular expression includes a plural expression.

[0054] The terms indicating directions such as up, down, left, right, front, back, inside, and outside used herein are only for convenience of description, and it is obvious to those skilled in the art that the terms may vary depending on the position of the reference object or the observer.

[0055] In addition, throughout the specification, when a component is referred to as “including” and “having” a component, it means that it can further include other components rather than excluding other components, unless specifically stated otherwise.

[0056] Figure 1 is a schematic cross-sectional view of a cylindrical lithium-sulfur battery cell according to an embodiment of the present disclosure, wherein a center pin is separated from an electrode assembly, Figure 2 is a cross-sectional view of a core of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure, Figure 3 is a plan view of a core of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure, Figure 4 is a perspective view of an insertion portion of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure, Figure 5 is a cross-sectional view showing that an insert portion is inserted into a core portion of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure, Figure 6 is a plan view showing that an insert portion is inserted into a core portion of a center pin inserted into a center hole of an electrode assembly according to an embodiment of the present disclosure, Figure 7 is a schematic cross-sectional view showing a core portion of a center pin coupled to an electrode assembly in a cylindrical lithium-sulfur battery cell according to an embodiment of the present disclosure, Figure 8 The insertion portion is shown Figure 7 A schematic cross-sectional view of a core in which the core is pressed against the electrode assembly by an insert, Fig. 9 yes Figure 2 Another embodiment of the invention is Fig.10 yes Figure 5 Another embodiment of .

[0057] Reference Figure 1 , the electrode assembly 10 is formed in a jelly roll type which winds a current collector and a separator 120 interposed between a long sheet-shaped positive electrode plate 110 and a negative electrode plate 130 coated with an electrode active material on a surface of the current collector.

[0058] That is, the electrode assembly 10 includes the positive electrode plate 110 , the negative electrode plate 130 , and the separator 120 , and is wound in one direction with the separator 120 interposed between the positive electrode plate 110 and the negative electrode plate 130 .

[0059] Here, when the electrode assembly 10 is wound, a winding core is placed at one end of the electrode assembly 10, and after the electrode assembly 10 is wound on the winding core, the winding core is removed, and then a center hole 140 is formed at the center of the removed winding core. Then, the center pin 20 is inserted into the center hole 140 to press the electrode assembly 10. The center pin 20 will be described in detail later.

[0060] In the positive electrode plate 110, a positive active material layer including a positive active material is formed on at least one surface of a positive current collector 40. A positive electrode tab may be attached to the positive electrode plate 110, and the positive electrode tab may be attached to an uncoated portion of the positive current collector 40 where the positive active material is not applied by a method such as ultrasonic fusion.

[0061] However, the present disclosure does not necessarily require the formation of the uncoated portion and is not limited to the method of attaching the positive electrode tab as described above, and various tab attaching techniques known at the time of filing the present disclosure may be used in the present disclosure.

[0062] Meanwhile, as the positive electrode current collector 40 , a thin metal plate having excellent conductivity, such as an aluminum (Al) foil, may be used, and the positive electrode tab may be made of, for example, aluminum (Al).

[0063] The negative electrode plate 130 is formed by applying a negative electrode active material to at least one surface of the negative electrode collector 60, and a negative electrode tab is attached to the negative electrode plate 130. Like the positive electrode tab, the negative electrode tab may also be attached to an uncoated portion of the negative electrode collector 60 where the negative electrode active material is not applied, and various attachment methods such as ultrasonic fusion may be applied.

[0064] Also, as described for the positive electrode plate 110 , the negative electrode plate 130 also does not need to have an uncoated portion and is not limited to the method of attaching the negative electrode tab as described above, and various tab attaching techniques known at the time of filing the present disclosure may be used in the present disclosure.

[0065] Also, as the negative electrode current collector 60 , a conductive metal thin plate such as copper (Cu) or nickel (Ni) foil may be used, and the negative electrode tab may be made of, for example, nickel (Ni).

[0066] The separator 120 is disposed between the positive electrode plate 110 and the negative electrode plate 130 to insulate the positive electrode plate 110 and the negative electrode plate 130 and allow active material ions to be exchanged between the positive electrode plate 110 and the negative electrode plate 130. The separator 120 may be used without particular limitation as long as it is conventionally used as the separator 120 in a lithium secondary battery.

[0067] Specifically, the separator 120 may be a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a stacked structure of two or more layers thereof.

[0068] Also, conventional porous nonwoven fabrics may be used, such as nonwoven fabrics made of high melting point glass fibers, polyethylene terephthalate fibers, etc. In addition, separators 120 coated with a coating including a heat-resistant polymer material such as a ceramic member or engineering plastic may also be used to ensure heat resistance or mechanical strength.

[0069] In the cylindrical lithium-sulfur battery cell 1 according to an embodiment of the present disclosure, the sulfur-based material may be selected from inorganic sulfur (S 8 )、Li 2 S n (n≥1), disulfide compounds (such as 2,5-dimercapto-1,3,4-thiadiazole, 1,3,5-trithiocyanuric acid, etc.), organic sulfur compounds and carbon-sulfur polymers ((C 2 S x )n, x=2.5 to 50, n≥2). Preferably, it may include inorganic sulfur (S 8 ).

[0070] In one embodiment of the present disclosure, the sulfur-based material may be included in the positive electrode active material in the form of a sulfur-carbon composite material composited with a carbon material. The positive electrode active material may include 80 wt % or more of the sulfur-carbon composite material based on 100 wt % of the positive electrode active material, and herein, the content of the sulfur-based material based on 100 wt % of the sulfur-carbon composite material is preferably 70 wt % or more.

[0071] In one embodiment of the present disclosure, the sulfur-carbon composite material may be compounded by simply mixing sulfur and carbon materials, or may have a coating form or a loaded form of a core-shell structure. The coating form of the core-shell structure is a coating form in which sulfur or carbon materials are coated with other materials, and in an embodiment, the surface of the carbon material may be wrapped with sulfur, and vice versa. Moreover, the carbon material has a porous structure having pores inside and on the surface of the body, and specifically, may be a form in which the internal pores are filled with sulfur.

[0072] The carbon material has a porous structure including a large number of irregular pores on the surface and inside, serving as a carrier that provides a skeleton on which sulfur can be uniformly and stably fixed, and compensates for the low conductivity of sulfur to allow electrochemical reactions to proceed smoothly.

[0073] In the sulfur-carbon composite material according to an embodiment of the present disclosure, the carbon material may be any carbon-based material having porosity and conductivity as long as it is generally used in the art.

[0074] Specific examples of carbon materials may include at least one selected from the group consisting of: graphite; graphene; carbon black such as mercerized black, acetylene black, Ketjen black, channel black, furnace black, lamp black and summer black; carbon nanotubes (CNTs) such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs); carbon fibers such as graphite nanofibers (GNFs), carbon nanofibers (CNFs) and activated carbon fibers (ACFs); graphites such as natural graphite, artificial graphite and expanded graphite; carbon nanorods; carbon nanobelts, carbon nanorods and activated carbon.

[0075] Furthermore, in one embodiment of the present disclosure, the sulfur-carbon composite material may be prepared by a compounding method comprising the following steps: (S1) mixing a carbon material and sulfur to form a mixture, and then (S2) compounding the mixture.

[0076] The mixing in step (S1) is to increase the mixing degree between sulfur and carbon material, and can be performed using a stirring device commonly used in the art. At this time, the mixing time and speed can also be selectively adjusted according to the content and conditions of the raw materials.

[0077] Moreover, the present disclosure does not particularly limit the composite method in step (S2), and a method commonly used in the art can be used. In one embodiment, a method commonly used in the art, such as dry composite or wet composite like spraying, can be used. In one embodiment, the following method can be used: wherein the mixture of sulfur and carbon material obtained after mixing is heat-treated so that molten sulfur can be uniformly coated on the inner and outer surfaces of the carbon material.

[0078] Meanwhile, in one embodiment of the present disclosure, a process of pulverizing the mixture of sulfur and carbon materials by a method such as ball milling may be performed before heat treatment. In one embodiment of the present disclosure, the heat treatment may be performed at a temperature of 120° C. to 160° C. for about 20 minutes to 24 hours, and a heating device such as an oven may be applied.

[0079] Since the sulfur-carbon composite material prepared by the above manufacturing method has a high specific surface area, high sulfur retention and a structure that improves sulfur utilization, it can not only improve the electrochemical reactivity of sulfur, but also enhance the accessibility and contact ability of the electrolyte, thereby improving the capacity and life characteristics of the lithium-sulfur battery.

[0080] In addition to the contents described in this specification regarding the configuration, materials, manufacturing method, etc. of the above-mentioned positive electrode plate 110, negative electrode plate 130 and separator 120, contents widely known to those skilled in the art can be used in the present disclosure, but their detailed description will be omitted in this specification.

[0081] Refer to Figure 1 and Figure 8 The center pin 20 is inserted into the center hole 140 of the jelly roll type electrode assembly 10 to compress the electrode assembly 10 as described above. The center pin 20 according to an embodiment of the present disclosure structurally supports the electrode assembly 10 and can apply a preset range of pressure in an outward direction from the winding center.

[0082] The center pin 20 may be configured to include a core portion 210 and an insertion portion 270. The center pin 20 may have a long rod-like appearance, but is not limited thereto.

[0083] Refer to Figures 1 to 3 The core 210 is inserted into the center hole 140 formed in the electrode assembly 10. Also, an opening 221 is formed in the core 210. Also, at least a portion of the core 210 (eg, a lower side of the core 210) is formed such that the size of the diameter is changed.

[0084] The center pin 20 is inserted into the center hole 140 of the electrode assembly 10 to apply pressure in the outward direction of the electrode assembly 10, whereby the center pin 20 is tightly fixed to the electrode assembly 10. In addition, the electrode assembly 10 accommodated in the battery can 30 can be fixed in close contact with the battery can 30 by the pressure of the center pin 20.

[0085] Also, the insert portion 270 is configured to be inserted into the opening 221 of the core 210 to adjust the size of the diameter of the core 210 .

[0086] The insert portion 270 may be configured in various ways. Figure 4 , the insertion portion 270 may be configured to include a head portion 271 and a rod portion. The head portion 271 may be formed, for example, in the shape of a disk. Moreover, the rod portion 272 extends from the head portion 271. The insertion portion 270 may be formed, for example, in the shape of a nail or a push pin.

[0087] Refer to Figure 5 and Figure 8 When the inserting part 270 is inserted into the core 210 and presses the core 210, the core 210 expands to both sides and presses the electrode assembly 10. Here, the core 210 is made of, for example, a flexible or elastic polymer material so that its shape can be easily deformed by the insertion and separation of the inserting part 270.

[0088] Furthermore, the inner surface of the core 210 and the outer surface of the insert 270 may be treated with a low-friction coating such as a Teflon coating to minimize friction, thereby facilitating insertion of the insert 270 into the core 210 .

[0089] Meanwhile, when manufacturing the cylindrical lithium-sulfur battery cell 1, the jelly-roll type electrode assembly 10 having the core portion 210 inserted is first accommodated in the battery can 30 before the insertion portion 270 is inserted into the core portion 210. When the insertion portion 270 is inserted into the core portion 210, the expansion portion 240 of the center pin 20 is expanded, and thus it may not be easy to insert the electrode assembly 10 into the external material.

[0090] Therefore, it is preferable that the electrode assembly 10 be inserted into the battery can 30 before the insertion part 270 is inserted into the core part 210. However, it is not limited thereto.

[0091] After the core 210 is inserted into the electrode assembly 10 in the battery can 30 in this manner, the insertion portion 270 is inserted to penetrate the support portion 220 of the core 210 , thereby coupling the core 210 and the insertion portion 270 .

[0092] Although the core part 210 may be formed in various shapes, it may be formed in a shape corresponding to the shape of the center hole 140 so that it may be inserted through the center hole 140 of the electrode assembly 10 .

[0093] The core 210 may include a supporting portion 220 , a connecting portion 230 , and an expansion portion 240 .

[0094] The support portion 220 is located at the upper side, and forms an opening 221 into which the insertion portion 270 is inserted. Figure 3 , the opening 221 may be formed, for example, at the center of the support portion 220. Figure 7 , the diameter of the support portion 220 is formed to be larger than the diameter of the central hole 140 of the electrode assembly 10 , whereby the support portion 220 may be located at the upper side of the electrode assembly 10 without being inserted into the central hole 140 .

[0095] One side of the connection part 230 is coupled to the support part 220, and the other side is coupled to the expansion part 240 to connect the support part 220 and the expansion part 240. The expansion part 240 is coupled to the connection part 230 and expanded on both sides by the insertion part 270 (see Figure 5 and Figure 8 ) to compress the electrode assembly 10 in the centrifugal direction.

[0096] The expansion part 240 may include a plurality of units. For example, the expansion part 240 may include a first unit 241 and a second unit 244, but is not limited thereto. However, for ease of description, the following will describe a case where the expansion part 240 includes the first unit 241 and the second unit 244.

[0097] Reference together Figure 2 and Figure 5 A preset space 247 is formed between the plurality of units, ie, the first unit 241 and the second unit 244 . Also, the insertion portion 270 inserted from the opening 221 is inserted through the space 247 .

[0098] Here, reference Figure 2 , the first unit 241 and the second unit 244 may be configured to have at least one protrusion 242 , 245 and at least one groove 243 , 246 , respectively.

[0099] Moreover, the protrusion 242 and the groove 243 of the first unit 241 and the groove 246 and the protrusion 245 of the second unit 244 may be alternately positioned to correspond to each other. That is, the protrusion 242 of the first unit 241 may be formed at the same position as the groove 246 of the second unit 244, and the groove 243 of the first unit 241 may be formed at the same position as the protrusion 245 of the second unit 244.

[0100] Here, the protrusion 242 and the groove 243 of the first unit 241 and the groove 246 and the protrusion 245 of the second unit 244 may be configured to contact each other, or to be spaced apart from each other.

[0101] For example, in Figure 2 , the protrusion 242 and groove 243 of the first unit 241 and the groove 246 and protrusion 245 of the second unit 244 do not contact each other on the upper side, but the protrusion 242 and groove 243 of the first unit 241 and the groove 246 and protrusion 245 of the second unit 244 are in contact with each other on the lower side, respectively. However, this configuration is one embodiment, and various modified embodiments are possible.

[0102] Moreover, when the protrusion 242 and groove 243 of the first unit 241 and the groove 246 and protrusion 245 of the second unit 244 contact each other, a portion of the protrusion 242 of the first unit 241 can be configured to engage with a portion of the groove 246 of the second unit 244, and a portion of the groove 243 of the first unit 241 can be configured to engage with a portion of the protrusion 245 of the second unit 244.

[0103] Reference Figure 2 , the protrusion 242 and the groove 243 of the first unit 241 may have a curvature within a preset range. For example, the protrusion 242 and the groove 243 of the first unit 241 may have a circular shape.

[0104] Also, the protrusion 245 and the groove 246 of the second unit 244 may also have a curvature within a preset range. For example, the protrusion 245 and the groove 246 of the second unit 244 may have a circular shape.

[0105] If curvatures are formed in the protrusions 242 , 245 and the grooves 243 , 246 in this manner, interference or friction is reduced when the insertion portion 270 is inserted, which has the effect of facilitating the insertion of the insertion portion 270 .

[0106] refer to Fig. 9 As another embodiment, curvature is formed in the protrusion 242 and the groove 243 of the first unit 241 and the groove 246 and the protrusion 245 of the second unit 244, but the degree of the curvature is different from Figure 2 The degree of curvature in .

[0107] As described above, the expansion portion 240 is expanded on both sides by the insertion portion 270, and with reference to Figure 2 Before the insertion part 270 is inserted, that is, before the expansion part 240 is expanded, the expansion part 240 may be formed in a shape in which the diameter size decreases from the top to the bottom. That is, the expansion part 240 may be formed in a shape in which the upper part is wide and the lower part is narrow.

[0108] In this manner, if the expansion portion 240 is formed in a shape of being wide at the top and narrow at the bottom, when the core 210 is inserted into the central hole 140 of the electrode assembly 10, a gap S is formed between the core 210 and the electrode assembly 10, as shown in FIG. Figure 7 As shown, and thus interference between the core 210 and the electrode assembly 10 is prevented, which has the effect of facilitating the insertion of the core 210.

[0109] Reference together Figure 2 and Figure 5 , the diameter of the connection portion 230 may be configured to be smaller than the diameter of the support portion 220 and also smaller than the diameter of the expansion portion 240. Moreover, the connection portion 230 is coupled to the center of the support portion 220, and the support portion 220 may be configured to have a wide width in the vertical direction at the center where the connection portion 230 is coupled, and to have a narrowing width in the vertical direction from the center to both ends.

[0110] Therefore, when the expansion portion 240 is expanded toward both sides by the insertion portion 270 , the support portion 220 and the expansion portion 240 do not interfere with each other.

[0111] refer to Figure 2 and Figure 5, the connection part 230 has a smaller outer diameter than the support part 220 and the expansion part 240. Also, the outer diameter of the uppermost end of the expansion part 240 may be equal to or smaller than the outer diameter of the support part 220. The insertion part 270 is inserted into the support part 220 and the connection part 230, and an opening is formed straightly in the support part 220 in a vertical direction and extends downward to be connected to the space.

[0112] The connection part 230 separates the support part 220 and the expansion part 240 so that when the expansion part 240 is expanded by the insertion of the insertion part, the lower end of the support part 220 and the upper part of the expansion part 240 do not interfere with each other. Figure 2 The support portion 220 and the expansion portion 240 are spaced apart by the width of the connection portion 230 , and the distance between the support portion 220 and the expansion portion 240 increases as moving in an outward direction from the center of the connection portion 230 ( W2 > W1 ).

[0113] In an embodiment, the support portion 220 may have a shape that is wide at the center where the connection portion 230 is formed, and gradually decreases in width from the center to the periphery. Figure 5 , the lower side of the support part 220 may be formed to be inclined in an upward direction from the center to the end.

[0114] Furthermore, by forming in this manner, even if the insertion portion 270 is inserted into the core portion 210 and the outer diameter of the expansion portion 240 is as Figure 5 As shown in the expansion, the support portion 220 and the expansion portion 240 may also be spaced apart by W3 to prevent interference between the support portion 220 and the expansion portion 240 .

[0115] Hereinafter, a method for manufacturing the electrode assembly 10 including the center pin 20 and the cylindrical lithium-sulfur battery cell 1 including the electrode assembly 10 according to the present disclosure will be described in detail.

[0116] In one embodiment of the present disclosure, first, the positive electrode plate 110 and the negative electrode plate 130 are wound around a winding core a preset number of times with the separator 120 interposed therebetween. However, the method of forming the electrode assembly 10 into a jelly roll shape may vary and is not limited to the above embodiment.

[0117] Next, the winding core is removed from the center of the wound jelly-roll type electrode assembly 10. Then, the core 210 is inserted into the center hole 140 formed in the center of the jelly-roll type electrode assembly 10 after the winding core is removed.

[0118] Here, the core part 210 may be formed such that an outer diameter of one end gradually decreases along a longitudinal direction. Also, the core part 210 may be inserted from an entrance of the central hole 140 of the electrode assembly 10 to an opposite end.

[0119] Next, the jelly roll type electrode assembly 10 inserted with the core part 210 is inserted into the cylindrical battery can 30. Here, before inserting the insertion part 270 into the core part 210, the lower ends of the electrode assembly 10 and the battery can 30 may be coupled by welding.

[0120] Next, the insertion portion 270 is inserted into the core portion 210 . Then, as the outer diameter of the core portion 210 is expanded by the insertion of the insertion portion 270 , the core portion 210 presses the electrode assembly 10 toward the battery can 30 from the center of the electrode assembly 10 .

[0121] Meanwhile, the electrolyte may be injected into the battery can 30 before and / or after the insertion of the insertion portion 270. In one embodiment of the present disclosure, the electrolyte may include an organic solvent and a lithium salt. The solvent serves as a medium in which ions involved in the electrochemical reaction of the battery can move.

[0122] As the organic solvent, those used in conventional lithium secondary battery electrolytes can be used without limitation, and for example, ethers, esters, amides, chain carbonates, cyclic carbonates, etc. can be used alone or in combination of two or more. Among them, ether-based compounds can generally be included.

[0123] The ether-based compound may include acyclic ethers and cyclic ethers.

[0124] For example, the acyclic ether may be at least one selected from the group consisting of dimethyl ether, ethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, dimethoxyethane, diethoxyethane, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether and polyethylene glycol methyl ethyl ether.

[0125] For example, the cyclic ether may be at least one selected from the group consisting of 1,3-dioxolane, 4,5-dimethyl-dioxolane, 4,5-diethyl-dioxolane, 4-methyl-1,3-dioxolane, 4-ethyl-1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, 2,5-dimethoxytetrahydrofuran, 2-ethoxytetrahydrofuran, 2-methyl-1,3-dioxolane, 2-vinyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2-methoxy-1,3-dioxolane, 2-ethyl-2-methyl-1,3-dioxolane, tetrahydrofuran. pyran, 1,4-dioxane, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene and dimethyl isosorbide, furan, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzopyran, 2-(2-nitrovinyl)furan, thiophene, 2-methylthiophene, 2-ethylthiophene, 2-propylthiophene, 2-butylthiophene, 2,3-dimethylthiophene, 2,4-dimethylthiophene and 2,5-dimethylthiophene, but are not limited thereto.

[0126] Examples of the ester in the organic solvent may be any one or a mixture of two or more selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone and ε-caprolactone, but are not limited thereto.

[0127] Specific examples of the linear carbonate compound may be any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methylpropyl carbonate, and ethyl methyl carbonate, or a mixture of two or more thereof, but are not limited thereto.

[0128] In addition, specific examples of cyclic carbonate compounds may include ethylene carbonate (EC), propylene carbonate (PC), 2-butylene carbonate, 2-butylene carbonate, 2-pentanediol carbonate, 2-pentanediol carbonate, vinylene carbonate, vinylene carbonate and halides thereof, or mixtures of two or more thereof. Examples of such halides include, but are not limited to, fluoroethylene carbonate (FEC) and the like.

[0129] Meanwhile, in the present disclosure, the lithium salt is a compound capable of providing lithium ions in an electrolyte. Examples of lithium salts may include LiPF 6 、LiClO 4 、LiAsF 6 , LiBF 4 、LiSbF6 、LiAlO 4 、LiAlCl 4 、LiCF 3 CO 2 、LiCF 3 SO 3 ,LiC 4 F 9 SO 3 、LiN(C 2 F 5 SO 3 ) 2 、LiCH 3 SO 3 、LiN(C 2 F 5 SO 2 ) 2 、LiN(CF 3 SO 2 ) 2 ,LiC 4 BO 8 、LiCl、LiBr、LiB 10 Cl 10 , LiI or LiB(C 2 O 4 ) 2 .

[0130] In one embodiment of the present disclosure, in terms of increasing the availability of sulfur and realizing a high-capacity and high-voltage battery, it is preferred that the lithium salt include Li-TFSI. More preferably, the lithium salt may include LiN (CF) in an amount of 80 wt % or more, 90 wt % or more, or 100 wt % based on 100 wt % of the total lithium salt. 3 SO 2 ) 2 (Li-TFSI).

[0131] The concentration of the lithium salt is in the range of 0.1-2.0 M, preferably 0.5-1 M, and more preferably 0.5-0.75 M. When the concentration of the lithium salt is within the above range, the electrolyte may have appropriate conductivity and viscosity, thereby exhibiting excellent electrolyte performance and effectively moving lithium ions.

[0132] If the concentration of the lithium salt is less than the above range, it may be difficult to ensure ionic conductivity suitable for battery operation. If it exceeds the above range, the viscosity of the electrolyte increases, which reduces the mobility of lithium ions, or the decomposition reaction of the lithium salt itself increases, which deteriorates the battery performance.

[0133] In a specific embodiment of the present disclosure, in an electrolyte comprising a first solvent, a second solvent and a lithium salt, a molar ratio of the lithium salt, the second solvent and the first solvent is 1:0.5-3:4.1-15.

[0134] Furthermore, in one embodiment of the present disclosure, a molar ratio of the lithium salt, the second solvent, and the first solvent may be 1:2:4-13, 1:3:3-10, or 1:4:5-10, and the electrolyte included in the lithium-sulfur battery of the present disclosure may include the first solvent including the fluorine-based ether compound at a higher content ratio than the second solvent including the ethylene glycol-based compound.

[0135] Also, see Figure 1 , Figure 7 and Figure 8 According to an embodiment of the present disclosure, a cylindrical lithium-sulfur battery cell 1 is configured to include an electrode assembly 10 , a battery can 30 , a positive electrode current collector 40 , a cell terminal 50 , and a negative electrode current collector 60 .

[0136] The detailed description of the electrode assembly 10 will be replaced by the above description.

[0137] The battery can 30 is formed in a cylindrical shape, has a through hole, and accommodates the electrode assembly 10. For example, the battery can 30 is formed in a cylindrical shape so that the electrode assembly 10 is accommodated inside the battery can 30, and the battery can 30 may be electrically connected to the negative electrode plate 130 of the electrode assembly 10. Therefore, the battery can 30 may have the same polarity as the negative electrode plate 130, that is, a negative electrode. However, it is not limited thereto.

[0138] Here, the diameter of the battery can 30 is formed to be larger than the diameter of the electrode assembly 10. A gap of a predetermined size is formed between the battery can 30 and the electrode assembly 10 (if the positive electrode collector 40 is coupled to the electrode assembly 10, between the battery can 30 and the positive electrode collector 40), and an insulator may be interposed between the gaps.

[0139] The battery can 30 may be made of a material having conductivity, such as metal. The material of the battery can 30 may be made of a conductive metal, such as aluminum, steel, stainless steel, etc., but is not limited thereto.

[0140] The positive electrode collector 40 is electrically connected to the positive electrode plate 110, and the positive electrode collector 40 is connected to the positive electrode plate 110 at an upper portion of the electrode assembly 10. For example, the positive electrode collector 40 may be made of a metal material having electrical conductivity.

[0141] The cell terminal 50 is made of a conductive metal material and can be coupled to a through hole formed in the battery can 30 to be electrically connected to the positive electrode collector 40 through the through hole. Also, the cell terminal 50 is electrically connected to the positive electrode plate 110 of the electrode assembly 10 through the positive electrode collector 40 to have a positive polarity.

[0142] That is, the cell terminal 50 may be used as a positive terminal. Also, the battery can 30 is electrically connected to the negative electrode plate 130 of the electrode assembly 10 as described above, thereby having a negative polarity.

[0143] The negative electrode collector 60 is electrically connected to the negative electrode plate 130. The negative electrode collector 60 may be coupled to a lower portion of the electrode assembly 10. The negative electrode collector 60 may be made of a conductive metal material such as aluminum, steel, copper, nickel, or the like.

[0144] The negative electrode collector 60 may be electrically connected to the battery can 30. To this end, the negative electrode collector 60 may be fixed with at least a portion of its edge portion interposed between the inner surface of the battery can 30 and the sealing gasket.

[0145] In one embodiment, at least a portion of the edge portion of the negative electrode current collector 60 may be fixed to the bead portion by welding while being supported on the bottom surface of the bead portion formed at the lower end of the battery can 30. In a modified embodiment, at least a portion of the edge portion of the negative electrode current collector 60 may be directly welded to the inner wall surface of the battery can 30.

[0146] Also, at least a portion of the edge of the negative electrode collector 60 may be electrically coupled to a surface adjacent to the sandwiched portion between the upper and lower surfaces of the beaded portion.

[0147] Fig.11 is a view schematically showing a configuration of a battery pack according to an embodiment of the present disclosure, and Fig.12 It is used to describe Fig.11 View of the battery pack of a vehicle.

[0148] refer to Fig.11 The battery pack 2 according to the embodiment of the present disclosure may include one or more cylindrical lithium-sulfur battery cells 1 according to the embodiment of the present disclosure as described above. In addition, the battery pack 2 may also include a battery pack housing 3 for accommodating the cylindrical lithium-sulfur battery cells 1, and various devices for controlling the charge and discharge of the cylindrical lithium-sulfur battery cells 1, such as a BMS, a current sensor, a fuse, etc.

[0149] Reference Fig.12 , the vehicle 4 according to the embodiment of the present disclosure may include the above-mentioned cylindrical lithium-sulfur battery cell 1 or battery pack 2. Moreover, the cylindrical lithium-sulfur battery cell 1 or battery pack 2 according to the embodiment of the present disclosure may be applied to the vehicle 4, for example, a predetermined vehicle 4 designed to use electric power, such as an electric vehicle or a hybrid vehicle.

[0150] The present disclosure has been described above with respect to a limited number of embodiments and drawings, but the present disclosure is not limited thereto, and it is apparent to those skilled in the art that various modifications and changes may be made thereto within the technical aspects of the present disclosure and the equivalent scope of the appended claims.

[0151] Meanwhile, terms indicating directions such as up, down, left, right, front, and rear are merely for convenience of description, and it is obvious to those skilled in the art that the terms may change according to the position of the element or the observer.

[0152] Industrial Applicability

[0153] The present disclosure relates to an electrode assembly and a cylindrical lithium-sulfur battery cell including the electrode assembly, as well as a battery pack and a vehicle including the cylindrical lithium-sulfur battery cell, and is particularly applicable to secondary battery-related industries.

Claims

1. A jelly roll type electrode assembly having a structure in which a positive electrode plate, a negative electrode plate and a separator interposed therebetween are wound in one direction and having a central hole formed therein, The electrode assembly includes a center pin inserted into the center hole to press the electrode assembly.

2. The electrode assembly according to claim 1, in, The center pin comprises: a core that is inserted into the central hole, has an opening formed therein, and varies in size in diameter in at least a portion thereof; and An insert portion is inserted into the opening of the core portion to adjust the size of the diameter of the core portion.

3. The electrode assembly according to claim 2, in, The core comprises: a support portion located at an upper side and having the opening formed therein; a connecting portion coupled to the supporting portion; and An expansion portion, which is coupled to the connection portion, is expanded on both sides through the insertion portion and presses the electrode assembly in a centrifugal direction.

4. The electrode assembly according to claim 3, in, The expansion part includes a plurality of units. There is a preset space between the multiple units, and wherein the insertion portion inserted from the opening is inserted through the space.

5. The electrode assembly according to claim 4, in, The expansion part includes a first unit and a second unit, wherein each of the first unit and the second unit has at least one protrusion and at least one groove, and The protrusions and the grooves of the first unit and the grooves and the protrusions of the second unit are alternately positioned to correspond to each other.

6. The electrode assembly according to claim 5, in, A portion of the protrusion of the first unit is configured to engage with a portion of the groove of the second unit, and a portion of the groove of the first unit is configured to engage with a portion of the protrusion of the second unit.

7. The electrode assembly according to claim 6, in, The protrusion and the groove of the first unit have a curvature within a preset range, and the protrusion and the groove of the second unit also have a curvature within a preset range.

8. The electrode assembly according to claim 7, in, The protrusion and the groove of the first unit have a circular shape, and the protrusion and the groove of the second unit also have a circular shape.

9. The electrode assembly according to claim 3, in, Before the insertion portion is inserted, the expansion portion is formed in a shape in which the size of the diameter decreases from the top to the bottom.

10. The electrode assembly according to claim 3, in, The diameter of the connecting portion is smaller than the diameter of the supporting portion, and is also smaller than the diameter of the expanding portion.

11. The electrode assembly according to claim 3, in, The connecting portion is coupled to the center of the supporting portion, and The support portion has a wide width in the vertical direction at the center where the connection portions are coupled, and has a narrowing width in the vertical direction from the center to both ends.

12. The electrode assembly according to claim 2, in, The inserting portion comprises: head; and A stem portion extends from the head portion.

13. A cylindrical lithium-sulfur battery cell comprising: The electrode assembly according to any one of claims 1 to 12; a cylindrical battery can in which the electrode assembly is housed; a positive electrode current collector, the positive electrode current collector being electrically connected to the positive electrode plate; a cell terminal connected to the positive electrode collector through a through hole of the battery can; as well as A negative electrode current collector is electrically connected to the negative electrode plate.

14. A battery pack comprising the cylindrical lithium-sulfur battery cell according to claim 13.

15. A vehicle comprising the cylindrical lithium-sulfur battery cell according to claim 13.

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