Cylindrical battery cell, battery including the same, motor vehicle, and current collector plate

Abstract

The present invention discloses a cylindrical battery cell, a battery pack including the same, and an automobile. The cylindrical battery cell includes a jelly-roll-type electrode assembly having a structure in which a sheet-like first electrode plate and a second electrode plate and a separator interposed between them are wound in one direction, the first electrode plate includes a first non-coated portion at a long side end where an active material layer is not coated, the first non-coated portion is exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly and is used as an electrode tab by itself, a battery can having an open portion in which the electrode assembly is housed and a partially closed portion on the opposite side to the open portion and electrically connected to the second electrode plate, a current collector plate electrically connected to the first non-coated portion of the first electrode plate and having a fuse portion formed therein that cuts off when an overcurrent flows, and a cell terminal connected to the current collector plate through a through hole in the closed portion of the battery can.

Description

Technical Field

[0001] The present invention relates to a cylindrical battery cell, a battery pack including the same, and an automobile.

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0147347 filed on October 29, 2021, Korean Patent Application No. 10-2022-0012575 filed on January 27, 2022, and Korean Patent Application No. 10-2022-0089234 filed on July 19, 2022, and all of the content disclosed in the specifications and drawings of the applications is incorporated into this application.

Background Art

[0003] Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are widely applied not only to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), etc. driven by an electric drive source.

[0004] Such secondary batteries are attracting attention as a new energy source for improving energy efficiency because they are environmentally friendly not only in that they can significantly reduce the use of fossil fuels but also in that they do not produce any by-products associated with energy use.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such a unit secondary battery cell is about 2.5V to 4.5V.

[0006] Therefore, when a higher output voltage is required, a plurality of battery cells are connected in series to form a battery pack. Also, a battery pack can be formed by connecting a plurality of battery cells in parallel according to the charge and discharge capacity required for the battery pack. Therefore, the number and electrical connection form of the battery cells included in the battery pack can be variously set according to the required output voltage or charge and discharge capacity.

[0007] On the other hand, as types of secondary battery cells, cylindrical, prismatic, and pouch-type battery cells are known. In the case of a cylindrical battery cell, a separator, which is an insulator, is interposed between the positive electrode and the negative electrode, and it is wound to form a jelly-roll-shaped electrode assembly, and this is inserted into the inside of a battery can together with an electrolyte to constitute a battery.

[0008] Here, when the battery can is connected to the negative electrode or the positive electrode (usually the negative electrode) to have a polarity, insulation is also required between the battery can and the jelly-roll-shaped electrode assembly.

[0009] On the other hand, recently, as cylindrical battery cells are applied to electric vehicles, the form factor of cylindrical battery cells has been increasing. That is, the diameter and height of the cylindrical battery cell are increasing compared to conventional cylindrical battery cells having form factors such as 18650 and 21700. The increase in the form factor brings an increase in energy density, an increase in safety against thermal runaway, and an improvement in cooling efficiency.

[0010] Here, as the form factor increases, the need to protect the cylindrical battery cell from overcurrent is also increasing. In one example, a fuse portion can be formed on the current collector plate. However, when a fuse portion is formed on the current collector plate, foreign matter generated when the fuse portion of the current collector plate blows due to overcurrent may flow into the inside of the jelly-roll-shaped electrode assembly. In this case, the separator may be damaged by the foreign matter, or a problem of internal short circuit due to the foreign matter may occur. Summary of the Invention Problems to be Solved by the Invention

[0011] The present invention was conceived under the background of the above-described prior art, and aims to provide a cylindrical battery cell capable of preventing foreign matter generated when a fuse part blows from flowing into the inside of a jelly roll-shaped electrode assembly by appropriately adjusting the position of the fuse part in a current collector plate, a battery pack including the same, and an automobile.

[0012] Alternatively, another object of the present invention is to provide a battery pack manufactured using a cylindrical battery cell having an improved structure and an automobile including the same.

[0013] However, the technical problems to be solved by the present invention are not limited to the above-described problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0014] A cylindrical battery cell according to one aspect of the present invention for achieving the above object has a jelly roll-type electrode assembly in which a sheet-shaped first electrode plate, a second electrode plate, and a separator interposed therebetween are wound in one direction. The first electrode plate includes a first non-coated portion at a long-side end portion where an active material layer is not coated. The first non-coated portion is exposed outside the separator while forming a plurality of winding turns with respect to the center of the electrode assembly, and serves as an electrode tab by itself. The electrode assembly includes an open portion for housing the electrode assembly, and a partial closing portion on the side opposite to the open portion. The battery cell further includes a battery can electrically connected to the second electrode plate, a current collector plate electrically connected to the first non-coated portion of the first electrode plate and having a fuse portion that blows when an overcurrent flows, and a cell terminal connected to the current collector plate through a through hole in the closing portion of the battery can.

[0015] Desirably, a flat portion parallel to the inner surface of the closing portion of the battery can is formed at least partially on the bottom surface of the cell terminal, and the current collector plate can be coupled to the flat portion of the cell terminal.

[0016] Desirably, the current collector plate can be coupled to a coupling surface formed by bending an end portion of the first non-coated portion.

[0017] Desirably, the electrode assembly includes a welding target region along the radial direction of the electrode assembly, and the current collector plate can be coupled to the first non-coated portion within the welding target region.

[0018] According to one aspect, the current collector plate includes an edge portion disposed at the upper portion of the electrode assembly, a non-coated portion coupling portion extending inward from the edge portion and coupling to the first non-coated portion, a terminal coupling portion spaced apart from the non-coated portion coupling portion and coupling to the cell terminal, and a connecting portion extending inward from the edge portion and connected to the terminal coupling portion, where the fuse portion is formed. The fuse portion may have a resistance that is greater than that of other regions under the condition that the same current flows.

[0019] Desirably, the edge portion may be in the form of a rim with at least a part of the inner region being empty.

[0020] Desirably, the non-coated portion coupling portion and the terminal coupling portion can be electrically connected via the edge portion.

[0021] Desirably, the terminal coupling portion may be located at the center of the inner space of the edge portion.

[0022] Desirably, the terminal coupling portion may have a diameter that is 100% to 110% of the diameter of the cavity existing in the core of the electrode assembly.

[0023] According to one aspect, the fuse portion may be at least one notch formed in the connecting portion.

[0024] Desirably, the notch may be formed at an end portion in the width direction of the connecting portion, on the upper surface of the connecting portion, or on the lower surface of the connecting portion.

[0025] Preferably, the notch may be formed to be recessed inward of the connecting portion in a direction of gradually or continuously decreasing the width or thickness of the connecting portion.

[0026] Preferably, the minimum width of the fuse portion may be 0.5 mm to 4.0 mm.

[0027] According to another aspect, the fuse portion may be at least one through hole formed in the connecting portion.

[0028] Preferably, the through hole may have a longest width of 0.2 mm to 6 mm.

[0029] According to still another aspect, the fuse portion may be wound by a tape.

[0030] Preferably, the tape may include a polyimide (PI) material.

[0031] Preferably, the fuse portion may be formed in the connecting portion so as to be separated from the center of the electrode assembly by a distance of 40% to 90% of its maximum radius.

[0032] According to one aspect, at least a partial section of the first non-coated portion may be divided into a plurality of segmented pieces along the winding direction of the electrode assembly.

[0033] Preferably, at least a part of the plurality of segmented pieces may be bent in the radial direction of the electrode assembly.

[0034] Preferably, at least a part of the plurality of segmented pieces may be overlapped multiple times along the radial direction of the electrode assembly.

[0035] According to another aspect, the rest of the plurality of segmented pieces are not bent, and the fuse portion may be displaced from the non-bent segmented pieces among the plurality of segmented pieces and located above the bent segmented pieces among the plurality of segmented pieces.

[0036] According to another aspect, the remaining of the plurality of segmented pieces are cut, and the fuse portion may be displaced from the cut segmented pieces among the plurality of segmented pieces and located above the bent segmented pieces among the plurality of segmented pieces.

[0037] Desirably, the welding pattern depicted by the welding beads formed on one surface of the terminal connection portion of the current collector plate may be depicted in a form surrounding the center portion of the bottom surface of the cell terminal.

[0038] Desirably, the welding pattern may be formed continuously or discontinuously.

[0039] Desirably, the tensile force of the welded portion formed between the terminal connection portion of the current collector plate and the bottom surface of the cell terminal may be 2 kgf or more.

[0040] Desirably, the converted diameter of the welding pattern depicted by the welding beads formed on one surface of the terminal connection portion of the current collector plate may be 2 mm or more. The converted diameter means the diameter of a circle when the area of the welding pattern is converted into the area of a circle.

[0041] According to one aspect, it may further include a cap plate configured to seal the opening portion of the battery can.

[0042] Desirably, the cap plate may be electrically separated from the electrode assembly and provided non-polar.

[0043] Desirably, a through hole is formed in the closing portion, and the cell terminal may be coupled to the through hole.

[0044] Desirably, it may further include an insulator interposed between the closing portion and the current collector plate.

[0045] Desirably, the insulator may include an insulating polymer material.

[0046] Desirably, the insulator may be composed of a material having elasticity.

[0047] Desirably, the insulator may include a central hole having a preset diameter at the center portion.

[0048] Desirably, the insulator may have a thickness corresponding to the distance between the inner surface of the closed portion of the battery can and the current collector plate.

[0049] Desirably, the upper surface of the insulator may contact the inner surface of the closed portion of the battery can, and the lower surface of the insulator may contact the upper surface of the current collector plate.

[0050] On one hand, the cell terminal includes a terminal insertion portion, and the terminal insertion portion may be inserted into the battery can from the through hole.

[0051] Desirably, the cell terminal may be fixed to the through hole by riveting the peripheral edge of the lower portion of the terminal insertion portion toward the inner surface of the upper end portion of the battery can.

[0052] Desirably, the diameter of the central hole of the insulator may be larger than or the same as the diameter of the terminal insertion portion.

[0053] Desirably, the terminal insertion portion of the cell terminal may penetrate the central hole of the insulator.

[0054] Desirably, the terminal insertion portion of the cell terminal may penetrate the central hole of the insulator and be electrically coupled to the current collector plate.

[0055] According to one aspect, it includes a sealing gasket interposed between the peripheral edge of the cap plate and the open portion of the battery can, and the battery can includes a beading portion press-fitted into the inside of the battery can in a region adjacent to the open portion, and the battery can includes a crimping portion that extends and is bent inside the battery can and surrounds and fixes the peripheral edge of the cap plate together with the sealing gasket.

[0056] Desirably, the crimping portion may be formed below the battery can with reference to the arrangement state of the battery can.

[0057] Desirably, the cap plate may include a vent notch that ruptures when the internal pressure of the battery can exceeds a critical value.

[0058] Desirably, the vent notch is formed on both sides of the cap plate and may be formed in at least one of a continuous circular pattern, a discontinuous circular pattern, and a linear pattern on the surface of the cap plate.

[0059] The vent notch is formed at the lower end of the battery can with reference to the arrangement state of the battery can. When the vent notch ruptures, the gas inside the battery can may be discharged from the lower end of the battery can.

[0060] According to another aspect, it may further include a lower current collector plate coupled to the lower part of the electrode assembly.

[0061] Desirably, at least a part of the edge of the lower current collector plate may be electrically coupled to the beading portion, and at least a part of the remaining portion except the end portion may be electrically connected to the second non-coated portion of the second electrode plate.

[0062] Desirably, at least a part of the end portion of the lower current collector plate may be electrically coupled to the surface adjacent to the crimping portion among the upper and lower surfaces of the beading portion.

[0063] Desirably, the lower current collector plate and the beading portion may be laser welded.

[0064] The problem of the present invention can also be solved by a battery pack including at least one of the aforementioned cylindrical battery cells and an automobile including at least one of the battery packs.

[0065] The current collector plate according to one aspect of the present invention for solving the above problems is a current collector plate that electrically connects a terminal on a closed portion of a battery can of a cylindrical battery cell and an electrode assembly, and includes an edge portion, a non-coated portion coupling portion that extends inward from the edge portion and couples with a non-coated portion of the electrode assembly, a terminal coupling portion that is spaced apart from the non-coated portion coupling portion with a space therebetween, a connecting portion that extends inward from the edge portion and is connected to the terminal coupling portion, and a fuse portion that is formed in the connecting portion and has a resistance greater than that of other regions under the application of the same current.

[0066] Desirably, the edge portion has a rim form having a space inside, and the non-coated portion coupling portion and the terminal coupling portion can be formed in the inner space of the edge portion.

[0067] Desirably, the non-coated portion coupling portion and the terminal coupling portion can be electrically connected via the edge portion and the connecting portion.

[0068] Desirably, the terminal coupling portion can be located at the center of the inner space of the edge portion.

Advantages of the Invention

[0069] According to one aspect of the present invention, it is possible to appropriately adjust the position of the fuse portion in the current collector plate to prevent foreign matter generated when the fuse portion blows from flowing into the inside of the jelly roll-shaped electrode assembly.

[0070] According to still another aspect of the present invention, it is possible to provide a battery pack manufactured using a cylindrical battery cell having an improved structure and an automobile including the same.

Brief Description of the Drawings

[0071]

Figure 1

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Figure 4

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Figure 8

Figure 9

Figure 10

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Figure 12

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Figure 16

Mode for Carrying Out the Invention

[0072] 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 the claims should not be construed as being limited to ordinary or dictionary meanings, and the inventors themselves must interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that they can appropriately define the concept of the terms in order to explain the invention in the best way.

[0073] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0074] In addition, for the purpose of assisting in the understanding of the invention, the attached drawings may show some components exaggerated rather than at actual scale. Note that the same reference numerals may be assigned to the same components in different embodiments.

[0075] FIG. 1 is a perspective view of a cylindrical battery cell according to an embodiment of the present invention, FIG. 2 is a cross-sectional perspective view showing a cross-section of the central portion of the cylindrical battery cell in FIG. 1, FIG. 3 is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present invention, FIG. 4 is a view showing a battery can in the cylindrical battery cell according to an embodiment of the present invention, FIG. 5 is a plan view of a current collector plate in the cylindrical battery cell according to an embodiment of the present invention, FIG. 6 is a modified embodiment according to one side of the current collector plate in FIG. 5, FIG. 7 is a modified embodiment according to the other side of the current collector plate in FIG. 5, and FIG. 8 is a cross-sectional view according to another embodiment of the cylindrical battery cell in FIG. 3.

[0076] A cylindrical battery cell 10 according to an embodiment of the present invention will be described with reference to the drawings.

[0077] Desirably, the cylindrical battery cell 10 can be, for example, a cylindrical battery cell 10 in which the form factor ratio (the value obtained by dividing the diameter of the cylindrical battery cell by the height, that is, the ratio of the diameter Φ to the height H) is greater than about 0.4.

[0078] Here, the form factor means a value indicating the diameter and height of the cylindrical battery cell 10. The cylindrical battery cell 10 according to an embodiment of the present invention can be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value indicating the form factor, the first two digits indicate the diameter of the cell, the next two digits indicate the height of the battery, and the last digit 0 indicates that the cross-section of the cell is circular. If the height of the cell exceeds 100 mm, three digits are required to indicate the height of the cell, so the last digit 0 can be omitted.

[0079] The battery cell according to an embodiment of the present invention can be a cylindrical battery cell 10 that is substantially cylindrical, has a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0080] The battery cell according to another embodiment can be a cylindrical battery cell 10 that is substantially cylindrical, has a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0081] The battery cell according to still another embodiment can be a cylindrical battery cell 10 that is substantially cylindrical, has a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.436.

[0082] The battery cell according to still another embodiment can be a cylindrical battery cell 10 that is substantially cylindrical, has a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0083] The battery cell according to still another embodiment can be a cylindrical battery cell 10 that is substantially cylindrical, has a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0084] Conventionally, battery cells with a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, 18650 cells, 21700 cells, etc. have been used. In the case of 18650 cells, its diameter is about 18 mm, its height is about 65 mm, and the form factor ratio is 0.277. In the case of 21700 cells, its diameter is about 21 mm, its height is about 70 mm, and the form factor ratio is 0.300.

[0085] Referring to FIGS. 2 and 3, a cylindrical battery cell 10 according to an embodiment of the present invention includes an electrode assembly 100, a cylindrical battery can 200, a current collector plate 300, and a cell terminal 400.

[0086] The electrode assembly 100 is configured in a jelly roll type having a structure in which a sheet-like first electrode plate and a second electrode plate and a separator interposed therebetween are wound in one direction.

[0087] Referring to FIG. 3, the first electrode plate includes a first non-coated portion 110 where the active material layer is not coated at the long side end. And the second electrode plate may also include a second non-coated portion 120 where the active material layer is not coated at the long side end. That is, at least one of the first electrode plate and the second electrode plate may include a non-coated portion where the active material is not coated at the long side end in the winding direction.

[0088] Here, the first non-coated portion 110 forms a plurality of winding turns with reference to the center of the electrode assembly 100 and is exposed outside the separator, and is used as an electrode tab by itself.

[0089] That is, the electrode assembly 100 is provided such that the sheet-like first electrode plate and the second electrode plate are wound in one direction with a separator interposed therebetween. The first electrode plate has a positive or negative polarity, and the second electrode plate can have a polarity opposite to that of the first electrode plate. That is, the first electrode plate is a positive electrode plate or a negative electrode plate, and the second electrode plate can be a negative electrode plate or a positive electrode plate having a polarity opposite to that of the first electrode plate. However, hereinafter, for the sake of convenience of explanation, the case where the first electrode plate is a positive electrode plate and the second electrode plate is a negative electrode plate will be mainly described.

[0090] The first electrode plate has a first electrode active material coated on one or both surfaces. And at the end of the first electrode plate, there is a first non-coated portion 110 on which the first electrode active material is not coated.

[0091] The second electrode plate has a second electrode active material coated on one or both surfaces. And at the end of the second electrode plate, there is a second non-coated portion 120 on which the second electrode active material is not coated.

[0092] And the first non-coated portion 110 of the first electrode plate and the second non-coated portion 120 of the second electrode plate are provided so as to face each other in opposite directions. The first non-coated portion 110 extends toward the closed portion 210 of the battery can 200, and the second non-coated portion 120 extends toward the open portion 220 of the battery can 200.

[0093] In the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be used without limitation as long as they are known active materials in the art.

[0094] In one example, the positive electrode active material has the general chemical formula A[A x M y O 2+z(A contains at least one or more elements of Li, Na, and K; M contains at least one or more elements selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Mo, Sc, Zr, Ru, and Cr; x≧0, 1≦x + y≦2, -0.1≦z≦2; the stoichiometric coefficients x, y, and z are selected such that the compound maintains electrical neutrality.) may contain an alkali metal compound represented thereby.

[0095] In another example, the positive electrode active material is an alkali metal compound xLiM disclosed in US6,677,082, US6,680,143, etc. 1 O2-(1 - x)Li2M 2 O3(M 1 (M contains at least one or more elements having an average oxidation state of 3; M 2 (M contains at least one or more elements having an average oxidation state of 4; 0≦x≦1).

[0096] In yet another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1‐x M 2 y P 1‐y M 3 z O 4‐z (M 1 (M contains at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg, and Al; M 2 (M contains at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 (M contains a halogen group element selectively containing F; 0 < a≦2, 0≦x≦1, 0≦y < 1, 0≦z < 1; the stoichiometric coefficients a, x, y, and z are selected such that the compound maintains electrical neutrality.), or it may be a lithium metal phosphate represented by Li3M2(PO4)3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Mg, and Al.].

[0097] Desirably, the positive electrode active material may include primary particles and / or secondary particles formed by aggregation of primary particles.

[0098] In one example, as the negative electrode active material, a carbon material, a lithium metal or a lithium metal compound, a silicon or a silicon compound, a tin or a tin compound, etc. may be used. Metal oxides such as TiO2 and SnO2 with a potential of less than 2V can also be used as the negative electrode active material. As the carbon material, both low-crystalline carbon and high-crystalline carbon can be used.

[0099] The separator may be a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as a polyethylene homopolymer, a polypropylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., used alone or laminated. In another example, the separator may be a normal porous non-woven fabric, for example, a non-woven fabric made of high-melting glass fibers, polyethylene terephthalate fibers, etc.

[0100] At least one surface of the separator may include a coating layer of inorganic particles. It is also possible that the separator itself consists of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded to a binder such that an interstitial volume exists between adjacent particles.

[0101] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. As this non-limiting example, the inorganic particles may include at least one or more substances selected from the group consisting of Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), BaTiO3, HfO2, SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0102] The electrolyte can be a salt having a structure such as A + B - Here, A + is an ion containing an alkali metal cation such as Li + , Na + , K + or a combination thereof. And B - is one or more anions selected from the group consisting of F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN- and (CF3CF2SO2)2N - and contains any one or more anions selected from the group.

[0103] Further, the electrolyte can be used by dissolving it in an organic solvent. Examples of the organic solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof that can be used.

[0104] The battery can 200 is formed in a cylindrical shape and houses the electrode assembly 100, and is electrically connected to the second electrode plate of the electrode assembly 100. Accordingly, the battery can 200 can have the same polarity as the second electrode plate. That is, when the second electrode plate is a negative electrode, the battery can 200 also has a negative electrode.

[0105] If the size of the electrode assembly 100 is increased while the size of the battery can 200 is determined by the standard, the overall capacity of the battery cell increases, but the distance between the battery can 200 and the electrode assembly 100 decreases.

[0106] That is, in order to increase the overall capacity of the battery cell, when the size of the electrode assembly 100 is increased, the distance between the battery can 200 and the electrode assembly 100 decreases. Therefore, in order to increase the capacity of the battery cell, it is necessary to interpose an insulator 600 between the reduced compartments of the battery can 200 and the electrode assembly 100. For this purpose, it is desirable that the thickness of the insulator 600 be as thin as possible.

[0107] Referring to FIG. 4, a closed portion 210 and an open portion 220 may be respectively formed on the battery can 200 so as to face each other.

[0108] For example, with reference to FIG. 4, an open portion 220 may be formed at the lower part of the battery can 200. The electrode assembly 100 is accommodated from the open portion 220 formed at the lower part of the battery can 200, and the electrolyte is also injected from the open portion 220 formed at the lower part of the battery can 200.

[0109] That is, the battery can 200 is a substantially cylindrical container having an open portion 220 formed at the lower part, and is made of a conductive material such as a metal, for example. The material of the battery can 200 may be exemplified by a conductive metal such as aluminum, steel, stainless steel, etc., but is not limited thereto. A Ni coating layer may be formed on the surface of the battery can 200.

[0110] Also, with reference to FIG. 4, a closed portion 210 may be formed at the upper part of the battery can 200. A through hole 211 is formed in the closed portion 210, and the cell terminal 400 can be coupled to the through hole 211 as shown in FIG. 3.

[0111] The insulator 600 is provided between the upper end of the electrode assembly 100 and the inner surface of the battery can 200 or between the current collector plate 300 coupled to the upper part of the electrode assembly 100 and the inner surface of the closing part 210 of the battery can 200. Referring to FIG. 3, the insulator 600 can be interposed between the closing part 210 and the current collector plate 300. The insulator 600 prevents contact between the current collector plate 300 and the battery can 200. That is, the insulator 600 is accommodated inside the battery can 200, covers at least a part of the electrode assembly 100, and is configured to block the electrical connection between the first non-coated part 110 and the battery can 200 or the electrical connection between the current collector plate 300 and the battery can 200. In addition, the insulator 600 can also be interposed between the upper end of the outer peripheral surface of the electrode assembly 100 and the side wall of the battery can 200. That is, the insulator 600 can also be interposed between the first non-coated part 110 and the side wall part of the battery can 200. Alternatively, as will be described later, an insulating tape 500 can be coupled between the upper end of the outer peripheral surface of the electrode assembly 100 and the side wall of the battery can 200 instead of the insulator 600. That is, the insulator 600 can be made of a material having insulating properties. For example, the insulator 600 can include an insulating polymer material, but is not limited thereto. For example, the insulator 600 can be made of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polypropylene (PP).

[0112] The insulator 600 can prevent contact between the current collector plate 300 and the battery can 200 and contact between the side surface of the first non-coated part 110 and the battery can 200 together with the insulating tape 500. That is, the insulator 600 prevents contact between the current collector plate 30 and the battery can 200, and the insulating tape 500 can prevent contact between the side surface of the electrode assembly 100, that is, the side surface of the first non-coated part 110 and the battery can 200. If there is a structure in which the current collector plate 300 does not exist, the insulator 600 can prevent contact between the upper part of the first non-coated part 110 and the battery can 200.

[0113] The insulator 600 may include, for example, an elastic material. Thereby, when vibration or an external impact is applied to the cylindrical battery cell 10, the insulator 600 can absorb the impact in the process of being compressed elastically and then returning to its original state. Therefore, even when vibration or an external impact is applied to the battery cell, damage to the internal components of the battery cell can be minimized.

[0114] The insulator 600 may be provided with a central hole having a preset diameter at the center. For example, the insulator 600 may be provided with a substantially circular central hole adjacent to the winding center. The presence of the central hole enables the cell terminal 400 to be in a state where it can contact the current collector plate 300 or the first non-coated portion 110. The terminal insertion portion 410 of the cell terminal 400 is coupled to the current collector plate 300 or the first non-coated portion 110 from the central hole formed in the insulator 600. The central hole formed in the insulator 600 may be formed at a position corresponding to the hole formed at the winding center of the electrode assembly 100.

[0115] On the other hand, if the welding joint between the cell terminal 400 and the terminal joint portion 330 of the current collector plate 300 is located inside the hole formed at the winding center of the electrode assembly 100, the electrode assembly 100 may be damaged. To prevent this, the flat portion formed at the lower end of the cell terminal 400 that is coupled to the terminal joint portion 330 may be located at the same height as the lower surface of the insulator 600 or may be located higher. In this case, the welding joint between the cell terminal 400 and the current collector plate 300 may be located outside the hole formed at the winding center of the electrode assembly 100.

[0116] Taking this into account, the thickness of the insulator 600 may be the same as or greater than the distance from the inner surface of the closing portion 210 of the battery can 200 to the flat portion provided at the lower end of the cell terminal 400. On the other hand, the insulator 600 fills the space between the inner surface of the closing portion 210 of the battery can 200 and the current collector plate 300 along the height direction so that no space for the electrode assembly 100 to move up and down is generated, and may have a thickness corresponding to the distance between the inner surface of the closing portion 210 of the battery can 200 and the current collector plate 300.

[0117] According to the other aspect, the upper surface of the insulator 600 may contact the inner surface of the closing portion 210 of the battery can 200, and the lower surface of the insulator 600 may contact the upper surface of the current collector plate 300.

[0118] A beading portion 240 and a crimping portion 250 may be formed at the lower part of the battery can 200. The beading portion 240 is formed by press-fitting the periphery of the outer peripheral surface of the battery can 200 inward in a region adjacent to the opening portion 220 of the battery can 200.

[0119] The beading portion 240 supports the electrode assembly 100 so that the electrode assembly 100 having a size substantially corresponding to the width of the battery can 200 does not come out from the opening portion 220 formed at the lower part of the battery can 200, and may also function as a support portion where the cap plate 230 is provided. Further, the beading portion 240 supports the outer peripheral surface of the sealing gasket 260. The beading portion 240 may be asymmetric with respect to a virtual plane passing through the innermost point. The asymmetric pattern is made in the sizing process of the battery can 200. The sizing process is a process of compressing the battery can 200 in the vertical direction to match the height of the cell to the form factor.

[0120] The crimping portion 250 is provided so as to extend inward of the battery can 200, be bent, and surround and fix the peripheral edge of the cap plate 230 together with the sealing gasket 260. Here, the crimping portion 250 is formed at the lower part of the battery can 200 with reference to the state in which the battery can 200 is disposed. For example, when the battery can 200 is disposed such that the cell terminal 400 is located at the upper part as shown in FIG. 3, the crimping portion 250 is formed at the lower part of the battery can 200 with reference to FIG. 3. And, as shown in FIG. 3, the crimping portion 250 is formed at the lower part of the beading portion 240.

[0121] However, the present invention does not exclude the case where the battery can 200 does not include at least one of the beading portion 240 and the crimping portion 250. In the present invention, when the battery can 200 does not include at least one of the beading portion 240 and the crimping portion 250, the fixing of the electrode assembly 100, or the fixing of the cap plate 230, or the sealing of the battery can 200 can be realized by at least one of the additional application of a component that can function as a stopper for the electrode assembly 100, the additional application of a structure where the cap plate 230 can be provided, and the welding of the battery can 200 and the cap plate 230.

[0122] With reference to FIG. 3, the crimping portion 250 is formed below the beading portion 240. The crimping portion 250 has a form that extends and bends so as to surround the peripheral edge of the cap plate 230 disposed below the beading portion 240. Due to the shape of the crimping portion 250 bent in this way, the cap plate 230 is fixed to the beading portion 21. Of course, such a crimping portion 250 may be omitted, and the cap plate 230 may be fixed while covering the open portion of the battery can 200 by another fixing structure. For example, in Korean Patent Publication No. 10-2019-0030016A of the present applicant, a cylindrical battery cell in which the beading portion is omitted is disclosed, and such a structure may be adopted in the present invention.

[0123] The current collector plate 300 is electrically connected to the first electrode plate above the electrode assembly 100. That is, the current collector plate 300 electrically connects the cell terminal 400 on the closing portion 210 of the battery can 200 of the cylindrical battery cell 10 and the electrode assembly 100.

[0124] Referring to FIG. 5, a fuse portion 350 that breaks when an overcurrent flows is formed on the current collector plate 300. The fuse portion 350 is formed on the connecting portion 340 and is configured to have a greater resistance than other regions under the application of the same current. The minimum width of the fuse portion can be 0.5 mm to 4.0 mm.

[0125] The current collector plate 300 is made of a conductive metal material and is connected to the first non-coated portion 110 of the electrode assembly 100.

[0126] The current collector plate 300 can be coupled to a coupling surface formed by bending the end of the first non-coated portion 110 in a direction parallel to the current collector plate 300. The bending direction of the first non-coated portion 110 can be, for example, a direction toward the winding center portion of the electrode assembly 100.

[0127] When the first non-coated portion 110 has such a bent form, the space occupied by the first non-coated portion 110 can be reduced to improve the energy density. Also, by increasing the coupling area between the first non-coated portion 110 and the current collector plate 300, the coupling force can be improved and the resistance can be reduced.

[0128] Referring to FIG. 5, the current collector plate 300 may include an edge portion 310, a non-coated portion coupling portion 320, a terminal coupling portion 330, and a connecting portion 340.

[0129] The edge portion 310 is disposed on the upper part of the electrode assembly and may have a substantially rim form with an inner space S formed. In the case of FIG. 5, the case where the edge portion 310 has a substantially circular rim form is shown, but the shape of the edge portion 310 is not limited thereto. The edge portion 310 may have a substantially square rim form, a hexagonal rim form, an octagonal rim form, or other forms different from those shown. The non-coated portion coupling portion 320 and the terminal coupling portion 330 may be formed in the inner space of the edge portion 310. And the non-coated portion coupling portion 320 and the terminal coupling portion 330 may be electrically connected by the edge portion 310 and the connecting portion 340. Here, the terminal coupling portion 330 may be located at the center of the inner space of the edge portion 310.

[0130] The non-coated portion coupling portion 320 extends inward from the edge portion 310 and is coupled to the first non-coated portion 110 of the electrode assembly 100. The non-coated portion coupling portion 320 can be coupled to the first non-coated portion 110 in various ways. For example, it can be coupled by welding such as laser welding, ultrasonic welding, or spot welding.

[0131] A plurality of non-coated part coupling parts 320 may be provided. The plurality of non-coated part coupling parts 320 are arranged at various intervals along the extension direction of the edge part 310, and desirably, may be arranged at substantially the same interval. The extension lengths of each of the plurality of non-coated part coupling parts 320 may be the same as each other, but are not limited thereto. At this time, the plurality of non-coated part coupling parts 320 may be configured to surround the terminal coupling part 330.

[0132] The terminal coupling part 330 is located inside the edge part 310 at a space from the non-coated part coupling part 320 and separated from the non-coated part coupling part 320. The terminal coupling part 330 may be coupled to a cell terminal 400 described later by welding. Here, the terminal coupling part 330 may be located, for example, at the center of the inner space S of the edge part 310. And the terminal coupling part 330 may be arranged at a position corresponding to a hole formed at the winding center part of the electrode assembly 100. The terminal coupling part 330 may have a diameter of 100% to 110% with respect to the diameter of the cavity existing in the core of the electrode assembly 100.

[0133] The non-coated part coupling part 320 and the terminal coupling part 330 are not directly connected, are arranged separately from each other, and are electrically connected by the edge part 310. Thus, the current collector plate 300 according to an embodiment of the present invention has a structure in which the non-coated part coupling part 320 and the terminal coupling part 330 are not directly connected but are connected via the edge part 310, so that when an impact and / or vibration occurs in the cylindrical battery cell 10, the impact applied to the coupling part between the non-coated part coupling part 320 and the first non-coated part and the coupling part between the terminal coupling part 330 and the cell terminal 400 can be dispersed. Therefore, the current collector plate 300 of the present invention can minimize or prevent damage to the welding part due to an external impact.

[0134] That is, the current collector plate 300 has a structure in which stress is concentrated at the connection part between the edge part 310 and the terminal coupling part 330 when an external impact is applied, and such a connection part is not a part where a welding part for coupling between parts is formed. Therefore, the occurrence of product defects due to damage to the welding part by an external impact can be prevented.

[0135] The connecting portion 340 extends inward from the edge portion 310 and is connected to the terminal connecting portion 330. The connecting portion 340 may be located between a pair of non-coated portion connecting portions 320 adjacent to each other. In this case, the distance from the connecting portion 340 to any one of the pair of non-coated portion connecting portions 320 along the extension direction of the edge portion 310 may be the same as the distance from the connecting portion 340 to the remaining one of the pair of non-coated portion connecting portions 320 along the extension direction of the edge portion 310.

[0136] And, although not shown, a plurality of connecting portions 340 may be provided. Each of the plurality of connecting portions 340 may be disposed between a pair of non-coated portion connecting portions 320 adjacent to each other. The plurality of connecting portions 340 may be arranged at the same intervals along the extension direction of the edge portion 310.

[0137] Here, when a plurality of non-coated portion connecting portions 320 and / or connecting portions 340 are provided, if the distances between the non-coated portion connecting portions 320 and / or the distances between the connecting portions 340 and / or the distances between the non-coated portion connecting portions 320 and the connecting portions 340 are formed to be constant, the flow of current from the non-coated portion connecting portion 320 to the connecting portion 340 or the flow of current from the connecting portion 340 to the non-coated portion connecting portion 320 can be smoothly formed.

[0138] At least a part of the connecting portion 340 may be formed to have a smaller width than the non-coated portion connecting portion 320, and a fuse portion 350 may be formed on one side of the connecting portion 340. When the width of the connecting portion is formed to be smaller than that of the non-coated portion connecting portion 320, when an overcurrent flows through the connecting portion 340 due to an increase in electrical resistance at the connecting portion 340, the resistance becomes larger compared to other parts, and heat increases. Here, since the fuse portion 350 is formed on the connecting portion 340, when an overcurrent occurs and heat increases in the connecting portion 340, the fuse portion 350 is broken and the flow of the overcurrent is interrupted.

[0139] Referring to FIG. 5, the fuse portion 350 may be at least one notch 351 formed in the connecting portion 340. Since the resistance is inversely proportional to the area, when the notch 351 is formed in the connecting portion 340 in this way and the area decreases at the portion where the notch 351 is formed, the resistance of that portion increases. When an overcurrent flows, heat increases at the notch 351 site and breakage occurs. Here, the notch 351 may be formed at both ends in the width direction of the connecting portion 340, on the upper surface of the connecting portion 340, or on the lower surface of the connecting portion 340. Desirably, the notch 351 may be formed to be recessed inwardly of the connecting portion 340 in a direction of gradually or continuously decreasing the width or thickness of the connecting portion 340. Alternatively, the notch 351 may not be formed on the plane and may be formed in the thickness direction of the connecting portion 340.

[0140] As another example, referring to FIG. 6, the fuse portion 350 may be at least one through-hole 352 formed in the connecting portion 340. The through-hole 352 may have a maximum width of 0.2 mm to 6 mm. Regarding the specific operation, since it is common with FIG. 5, the detailed description replaces the above-mentioned description.

[0141] As yet another example, referring to FIG. 7, a tape 353 may be coupled to the fuse portion 350. When the tape 353 is coupled to the fuse portion 350 of the connecting portion 340, when heat is generated in the connecting portion 340, heat dissipation is inhibited by the tape 353 and heat is not released, so heat rises at the portion where the tape 353 is attached. Then, breakage occurs at the attachment portion of the tape 353 due to the increased heat. Here, the tape 353 may be made of various materials. For example, it may be made of polyimide (PI) that is not easily deformed by heat, but is not limited thereto.

[0142] As will be described later, at least a partial section of the first non-coated portion 110 of the electrode assembly 100 is divided into a plurality of segmented pieces 61, 61', and at least a part of the plurality of segmented pieces 61, 61' is bent along a preset direction, and the plurality of segmented pieces 61, 61' can be configured to be bent and superposed multiple times. At this time, the remaining of the plurality of segmented pieces 61, 61' can be maintained so as not to be bent, that is, a part of the plurality of segmented pieces 61, 61' is bent, and the remaining can maintain a form protruding along the winding axis direction without being bent. Or, the remaining non-bent part of the plurality of segmented pieces 61, 61', that is, the part maintaining the form protruding along the winding axis direction, can be cut off.

[0143] When the plurality of segmented pieces 61, 61' are bent and superposed multiple times, no gap is formed between the superposed plurality of segmented pieces 61, 61'. Therefore, when the fuse portion 350 of the current collector plate 300 is cut off due to an overcurrent, foreign matter generated will not flow into the inside of the jelly roll-shaped electrode assembly 100. However, if a part of the plurality of segmented pieces 61, 61' remains unbent or the unbent part of the plurality of segmented pieces 61, 61' is cut off, a gap is formed between the plurality of segmented pieces 61, 61' in this part. Therefore, foreign matter generated when the fuse portion 350 is cut off can flow into the inside of the jelly roll-shaped electrode assembly 100. If foreign matter flows into the inside of the jelly roll-shaped electrode assembly 100, the separation membrane may be damaged by the foreign matter, or a problem of internal short circuit due to the foreign matter may occur.

[0144] According to an embodiment of the present invention, the cylindrical battery cell 10 solves the above problem by appropriately adjusting the position of the fuse portion 350 formed in the connecting portion 340. For example, the fuse portion 350 is configured to be displaced from the non-folded segment or the cut segment among the plurality of segment pieces 61, 61' and located above the folded segment pieces 61, 61' among the plurality of segment pieces 61, 61'. According to this, even if the fuse portion 350 is cut and foreign matter is generated, the foreign matter will fall above the folded segment pieces 61, 61' among the plurality of segment pieces 61, 61'. As described above, when the plurality of segment pieces 61, 61' are folded and overlapped multiple times, no space is formed between the plurality of segment pieces 61, 61', so that the foreign matter does not flow into the inside of the jelly roll-shaped electrode assembly 100. Therefore, it has the effect of preventing damage to the separator and / or internal short circuit due to foreign matter. Desirably, the fuse portion 350 can be formed on the connecting portion 340 so as to be separated by a distance of 40% to 90% of the maximum radius from the center of the electrode assembly 100.

[0145] The current collector plate 300 can be coupled to the terminal insertion portion 410 of the cell terminal 400. That is, a flat portion parallel to the inner surface of the closing portion 210 of the battery can 200 is formed on at least a part of the bottom surface of the terminal insertion portion 410 of the cell terminal 400, and the current collector plate 300 can be coupled to the flat portion of the cell terminal 400.

[0146] The electrode assembly 100 includes a welding target region where the number of overlapping layers of the segment pieces in the first non-coated portion 110 is maintained constant along the radial direction of the electrode assembly 100, and the current collector plate 300 can be coupled to the first non-coated portion 110 within the welding target region. In this region, since the number of overlapping layers is maintained at the maximum, it may be advantageous for the welding of the current collector plate 300 and the first non-coated portion 110 described later to be performed within this region. This is, for example, in the case of applying laser welding. When increasing the output of the laser to improve the welding quality, it is to prevent the laser beam from penetrating the first non-coated portion 110 and damaging the electrode assembly 100. Also, this is to effectively prevent foreign matter such as welding spatter from flowing into the inside of the electrode assembly 100.

[0147] The electrical connection portion of the terminal insertion portion 410 can be, for example, substantially cylindrical. Of course, the shape of the electrical connection portion of the terminal insertion portion 410 is not limited thereto. The electrical connection portion of the terminal insertion portion 410 can have various forms such as, for example, a cylindrical shape with an elliptical cross-section, a square prism shape, a hexagonal prism shape, an octagonal prism shape, etc. The bottom surface of the electrical connection portion of the terminal insertion portion 410 can be formed to be at least partially substantially flat.

[0148] The connection between the bottom surface of the central region of the terminal insertion portion 410 and the current collector plate 300 can be performed, for example, by laser welding, spot welding or ultrasonic welding. Welding can be performed by irradiating a laser through a hole formed at the winding center of the electrode assembly 100, or by inserting a tool for ultrasonic welding or spot welding to form a weld bead on one surface of the current collector plate 300 (the surface facing the hole formed at the winding center of the electrode assembly 100). A guide pipe (not shown) for welding work can be inserted into the hole formed at the winding center. When welding work is performed with the guide pipe inserted, the risk of damage to the separation film forming the inner wall surface of the hole formed at the winding center can be reduced.

[0149] The welding pattern depicted by the weld bead formed on one surface of the terminal connection portion 330 of the current collector plate 300 can be depicted in a form surrounding the center portion of the bottom surface of the electrical connection portion of the terminal insertion portion 410. The welding pattern can be, for example, substantially circular, or alternatively, can be in the form of a polygon such as substantially elliptical, substantially square, hexagonal, octagonal, etc. The welding pattern formed by the weld bead can be formed continuously or discontinuously. Examples of the shape of the welding pattern formed by the weld bead such as circular, elliptical, polygon, etc. do not mean geometrically perfect circles, ellipses, polygons, etc.

[0150] On the other hand, the diameter of the flat portion formed on the bottom surface of the electrical connection portion of the terminal insertion portion 410 can be determined in consideration of the welding strength with the current collector plate 300. The tensile force of the welded portion between the flat portion and the current collector plate 300 can be at least approximately 2 kgf or more, 5 kgf or more, or 6 kgf or more, or 7 kgf or more, or 8 kgf or more, or 9 kgf or more, or 10 kgf or more. It is desirable to increase the tensile force of the welded portion as much as possible within the allowable range by optimally selecting the welding method.

[0151] In order to satisfy the condition of the tensile force of the welded portion, the diameter (or maximum width) of the welding pattern formed on the flat portion can be at least approximately 2 mm. The diameter of the welding pattern is obtained by converting the area S of the weld bead shown on the surface of the welding site into the area of a circle (πr 2 ), and can be defined as the converted diameter of the circle (2×(S / π) 0.5 ).

[0152] The flat portion formed on the bottom surface of the electrical connection portion of the terminal insertion portion 410 becomes a weldable region. The diameter of the weldable region can be approximately 3 mm to 14 mm. If the diameter of the weldable region is less than about 3 mm, it is difficult to secure a welding pattern with a diameter (converted diameter) of 2 mm or more. In particular, when forming a welding pattern using laser welding, due to the interference of the laser beam, it is difficult to secure a welding pattern with a diameter of 2 mm or more. If the diameter of the weldable region exceeds about 14 mm, the diameter of the terminal exposed portion of the cell terminal 400 also becomes larger than that, and as a result, it becomes difficult to sufficiently secure the outer surface area of the battery can 200 used as an electrode terminal having the opposite polarity to the cell terminal 400.

[0153] Considering the diameter condition of the welding pattern and the diameter condition of the weldable region, the ratio of the area of the welding pattern to the area of the weldable region required to ensure a tensile force of at least about 2 kgf or more in the welded portion is about 2.04% (π1 2 / π7 2 ) to 44.4% (π1 2 / π1.5 2 ).

[0154] In one example, when the flat portion formed on the bottom surface of the electrical connection portion of the terminal insertion portion 410 and the current collector plate 300 are welded by a laser, and the welding beads are welded while drawing continuous or discontinuous lines in the form of an arc pattern, the diameter of the arc welding pattern is desirably about 2 mm or more, preferably about 4 mm or more. When the diameter of the arc welding pattern satisfies such conditions, the tensile force of the welded portion can be increased to about 2 kgf or more, ensuring sufficient welding strength.

[0155] In another example, when the flat portion formed on the bottom surface of the electrical connection portion of the terminal insertion portion 410 and the current collector plate 300 are welded by ultrasonic waves and welded in a circular pattern, the diameter of the circular welding pattern is desirably about 2 mm or more. When the diameter of the circular welding pattern satisfies such conditions, the tensile force of the welded portion can be increased to about 2 kgf or more, ensuring sufficient welding strength.

[0156] The diameter of the flat portion formed on the bottom surface of the cell terminal 400 that becomes the weldable region can be adjusted in the range of about 3 mm to 14 mm. If the radius of the flat portion is less than about 3 mm, it is difficult to form a welding pattern having a diameter of about 2 mm or more using a laser welding tool, an ultrasonic welding tool, etc.

[0157] On the other hand, the cylindrical battery cell 10 according to an embodiment of the present invention has a structure in which the bottom surface of the electrical connection portion of the terminal insertion portion 410 is welded and joined onto the current collector plate 300 as described above. As a result, the bonding area between the current collector plate 300 and the cell terminal 400 can be maximized. That is, at least a part of the bottom surface of the electrical connection portion is formed flat, whereby the bonding area between the cell terminal 400 and the current collector plate 300 can be maximized. Therefore, the cylindrical battery cell 10 according to an embodiment of the present invention can ensure a smooth current flow at the bonding portion between the current collector plate 300 and the cell terminal 400 when a large amount of current flows due to rapid charging. As a result, effects such as shortening of the charging time and reduction of the heat generation amount can be achieved.

[0158] The current collector plate 300 is coupled to the upper part of the electrode assembly 100. Also, the current collector plate 300 is coupled to the cell terminal 400. That is, the current collector plate 300 electrically connects the first non-coated portion 110 of the electrode assembly 100 and the cell terminal 400. The current collector plate 300 is made of a conductive metal material and is connected to the first non-coated portion 110. Although not shown, the current collector plate 300 may have a plurality of irregularities formed radially on its lower surface. When the irregularities are formed, the current collector plate 300 can be pressed to press-fit the irregularities into the first non-coated portion 110.

[0159] On the bottom surface of the cell terminal 400, that is, on the bottom surface of the electrical connection portion of the terminal insertion portion 410, a flat portion that is at least partially substantially parallel to the inner surface of the closing portion 210 of the battery can 200 is formed, and the current collector plate 300 can be coupled to this flat portion.

[0160] The current collector plate 300 is coupled to the end of the first non-coated portion 110. The connection between the first non-coated portion 110 and the current collector plate 300 can be performed, for example, by laser welding. Laser welding can be performed in a manner of partially melting the base material of the current collector plate 300, or can be performed with a solder for welding interposed between the current collector plate 300 and the first non-coated portion 110. In this case, it is desirable that the solder has a melting point lower than that of the current collector plate 300 and the first non-coated portion 110.

[0161] The current collector plate 300 can be coupled to a coupling surface formed by bending the end of the first non-coated portion 110 in a direction parallel to the current collector plate 300. The bending direction of the first non-coated portion 110 can be, for example, the direction toward the winding center of the electrode assembly 100, that is, the core. When the first non-coated portion 110 has such a bent form, the space occupied by the first non-coated portion 110 can be reduced to improve the energy density. Also, by increasing the coupling area between the first non-coated portion 110 and the current collector plate 300, the effects of improving the coupling force and reducing the resistance can be achieved.

[0162] The cell terminal 400 is made of a conductive metal material, and is coupled to a through hole 211 formed in the closing portion 210 of the battery can 200 to be electrically connected to the current collector plate 300. Then, the cell terminal 400 is electrically connected to the first electrode plate of the electrode assembly 100 via the current collector plate 300, and thereby has a positive polarity. That is, the cell terminal 400 can function as a positive electrode terminal which is a first electrode terminal. And the battery can 200 is electrically connected to the second electrode plate of the electrode assembly 100 as described above, and thereby has a negative polarity.

[0163] The cell terminal 400 may include a terminal insertion portion 410. The terminal insertion portion 410 is inserted into the battery can 200 from a through hole 211 formed in the closing portion 210 of the battery can 200, and the lower end portion thereof may be electrically connected to the first non-coated portion 110.

[0164] The terminal insertion portion 410 may penetrate the battery can 200 and the insulator 600 simultaneously to be coupled to the current collector plate 300 or the first non-coated portion 110. The peripheral edge portion of the lower part of the terminal insertion portion 410 may be pressed by a caulking jig and be riveted toward the inner surface of the upper end portion of the battery can 200 to be fixed to the through hole.

[0165] That is, the peripheral edge portion of the lower part of the terminal insertion portion 410 may have a form bent toward the inner surface of the battery can 200 by the application of the caulking jig. For this reason, the maximum width of the end portion of the terminal insertion portion 410 may be formed larger than the maximum width of the hole of the battery can 200 formed by the penetration of the terminal insertion portion 410.

[0166] On the other hand, as another embodiment, the terminal insertion portion 410 may not have a form bent toward the inner surface of the battery can 200. For example, referring to FIG. 8, the terminal insertion portion 410 may be substantially cylindrical and penetrate a hole located substantially at the center of the upper surface of the battery can 200.

[0167] In an embodiment of the present invention, the terminal insertion portion 410 may have a circular planar shape, but is not limited thereto. The terminal insertion portion 410 may alternatively be polygonal, star-shaped, a shape having branches extending from the center, or the like.

[0168] The terminal insertion part 410 of the cell terminal 400 can penetrate through the central hole of the insulator 600. And the diameter of the central hole of the insulator 600 can be larger than or the same as the diameter of the terminal insertion part 410. And the terminal insertion part 410 of the cell terminal 400 can penetrate through the central hole of the insulator 600 and be electrically coupled to the current collector plate 300.

[0169] Referring to FIG. 3, the cap plate 230 is configured to seal the opening part 220 of the battery can 200. The cap plate 230 can be made of, for example, a metal material in order to ensure rigidity.

[0170] The cap plate 230 seals the opening part 220 formed at the lower end of the battery can 200. The cap plate 230 can be separated from the electrode assembly 100 and provided non-polar. That is, even when the cap plate 230 is provided with a conductive metal material, it may not have a polarity. The fact that the cap plate 230 has no polarity means that the cap plate 230 is electrically insulated from the battery can 200 and the cell terminal 400. Thus, the cap plate 230 may not have a polarity, and its material does not necessarily have to be a conductive metal.

[0171] The cap plate 230 can be provided and supported on the beading part 240 formed on the battery can 200. Also, the cap plate 230 is fixed by the crimping part 250. A sealing gasket 260 can be interposed between the cap plate 230 and the crimping part 250 of the battery can 200 in order to ensure the airtightness of the battery can 200. That is, the sealing gasket 260 can be provided so as to be interposed between the peripheral part of the cap plate 230 and the opening part 220 of the battery can 200.

[0172] On the other hand, the battery can 200 of the present invention may not include at least one of the beading portion 240 and the crimping portion 250. In this case, the sealing gasket 260 can be interposed between the fixing structure provided on the open portion 220 side of the battery can 200 and the cap plate 230 to ensure the airtightness of the battery can 200.

[0173] The vent notch 231 can be formed in the cap plate 230 so as to rupture when the pressure inside the battery can 200 exceeds a critical value.

[0174] For example, the vent notch 231 may be formed on both sides of the cap plate 230, and can be formed in at least one of a continuous circular pattern, a discontinuous circular pattern, and a linear pattern on the surface of the cap plate 230. Also, the vent notch 231 can be formed in various other patterns.

[0175] The vent notch 231 is formed at the lower end of the battery can 200 with reference to the arrangement state of the battery can 200, and can be provided such that when the vent notch 231 ruptures, the gas inside the battery can 200 is discharged from the lower end of the battery can 200.

[0176] For example, as shown in FIG. 3, when the battery can 200 is arranged such that the cell terminal 400 is located at the upper end, the vent notch 231 can be formed at the lower end of the battery can 200 with reference to FIG. 3.

[0177] The vent notch 231 can be formed as a region having a thickness thinner than that of the peripheral region in the cap plate 230.

[0178] Since the vent notch 231 is thinner than the peripheral region, it is more easily broken than the peripheral region, and when the internal pressure of the battery can 200 increases above a certain level, the gas generated inside the battery can 200 can be discharged by the breakage of the vent notch 231.

[0179] For example, the vent notch 231 can be formed by making a cut (notching) on one or both sides of the cap plate 230 to partially reduce the thickness of the battery can 200.

[0180] The cylindrical battery cell 10 according to an embodiment of the present invention can have a structure in which both the positive electrode terminal and the negative electrode terminal are present at the upper part, whereby the upper structure becomes more complex than the lower structure.

[0181] Therefore, a vent notch 231 can be formed in the cap plate 230 forming the lower surface of the cylindrical battery cell 10 for smooth discharge of the gas generated inside the battery can 200.

[0182] Thus, when the gas generated inside the battery can 200 provided in the cylindrical battery cell 10 is discharged downward, it can also be advantageous for the safety of the user. For example, when the cylindrical battery cell 10 is disposed directly below the driver's seat of an electric vehicle, if the gas is discharged upward, there may be a risk of a safety accident for the driver.

[0183] However, when the gas is discharged downward from the battery can 200 like the cylindrical battery cell 10 according to an embodiment of the present invention, the above-mentioned problems do not occur even if the cylindrical battery cell 10 is disposed directly below the driver's seat in an electric vehicle.

[0184] Referring to FIG. 3, it is desirable that the lower end portion of the cap plate 230 is located above the lower end portion of the battery can 200. In this case, even if the lower end portion of the battery can 200 contacts the ground or the bottom surface of the housing for the configuration of the module or the pack, the cap plate 230 does not contact the ground or the bottom surface of the housing for the configuration of the module or the pack.

[0185] Therefore, it is possible to prevent a phenomenon in which the pressure required for breaking the vent notch 231 differs from the design value due to the weight of the cylindrical battery cell 10, thereby ensuring the smoothness of the breaking of the vent notch 231.

[0186] Referring to FIG. 3, the lower current collector plate 700 is coupled to the lower part of the electrode assembly 100. The lower current collector plate 700 is made of a conductive metal material such as aluminum, steel, copper, nickel, etc., and is electrically connected to the second non-coated portion 120 of the second electrode plate.

[0187] Desirably, the lower current collector plate 700 is electrically connected to the battery can 200. For this purpose, at least a part of the edge of the lower current collector plate 700 can be fixed in an intervening state between the inner surface of the battery can 200 and the sealing gasket 260.

[0188] In one embodiment, at least a part of the edge of the lower current collector plate 700 can be fixed to the beading portion 240 by welding while being supported on the lower surface of the beading portion 240 formed at the lower end of the battery can 200. In a modified embodiment, at least a part of the edge of the lower current collector plate 700 can be directly welded to the inner wall surface of the battery can 200.

[0189] Desirably, at least a part of the remaining portion of the lower current collector plate 700 excluding the coupling portion of the beading portion can be coupled to the folded surface of the second non-coated portion 120, for example, by laser welding.

[0190] For example, at least a part of the edge of the lower current collector plate 700 can be electrically coupled to the surface adjacent to the crimping portion 250 among the upper and lower surfaces of the beading portion 240.

[0191] On the other hand, the electrode assembly 100 according to an embodiment of the present invention includes a first electrode plate and a second electrode plate. The first electrode plate includes a first non-coated portion 110, and the second electrode plate may include a second non-coated portion 120. And at least a partial section of the first non-coated portion 110 and / or the second non-coated portion 120 may be divided into a plurality of segmented pieces, and the structure of the segmented pieces will be described in detail below.

[0192] FIG. 9 is a plan view showing the structure of an electrode plate according to an embodiment of the present invention.

[0193] Referring to FIG. 9, in the non-coated portion 43 of the electrode plate 60, the heights of the core-side non-coated portion B1 and the outer-periphery-side non-coated portion B3 are 0 or more, and are relatively smaller than those of the intermediate non-coated portion B2. Also, the heights of the core-side non-coated portion B1 and the outer-periphery-side non-coated portion B3 may be the same or different.

[0194] Desirably, at least a part of the intermediate non-coated portion B2 may include a plurality of segmented pieces 61. The plurality of segmented pieces 61 may increase in height stepwise from the core side to the outer-periphery side.

[0195] The segmented piece 61 may be notched by a laser. The segmented piece 61 may be formed by a known metal foil cutting process such as ultrasonic cutting or punching.

[0196] In FIG. 9, in order to prevent damage to the active material layer 42 and / or the insulating coating layer 44 during the bending process of the non-coated portion 43, it is desirable to provide a predetermined gap between the lower end of the cutting line (C4 in FIG. 10) between the segmented pieces 61 and the active material layer 42. This is because stress concentrates near the lower end of the cutting line when the non-coated portion 43 is bent. The gap is desirably 0.2 to 4 mm. When the gap is adjusted within such a numerical range, it is possible to prevent the active material layer 42 and / or the insulating coating layer 44 near the lower end of the cutting line from being damaged by the stress generated during the bending process of the non-coated portion 43. Also, the gap can prevent damage to the active material layer 42 and / or the insulating coating layer 44 due to the tolerance during the notching or cutting of the segmented piece 61. Desirably, when the electrode plate 60 is wound, at least a part of the insulating coating layer 44 may be exposed outside the separator film. In this case, the insulating coating layer 44 can support the bending point when the segmented piece 61 is bent.

[0197] The plurality of segmented pieces 61 may form a plurality of segmented piece groups as advancing from the core side to the outer-periphery side. At least one or more of the width, height, and separation pitch of the segmented pieces belonging to the same segmented piece group may be substantially the same.

[0198] FIG. 10 is a diagram showing the definition of the width, height, and separation pitch of the segmented piece 61 according to an embodiment of the present invention. Referring to FIG. 10, the width C1, height C2, and separation pitch C3 of the segmented piece 61 are designed to prevent the non-coated portion 43 from tearing and to improve the welding strength by sufficiently increasing the number of overlapping layers of the non-coated portion 43 to prevent abnormal deformation of the non-coated portion 43 during the bending process of the non-coated portion 43. Abnormal deformation means that the non-coated portion below the bending point cannot maintain a straight state and collapses and is irregularly deformed.

[0199] Preferably, the width C1 of the segmented piece 61 can be adjusted in the range of 1 to 8 mm. If C1 is less than 1 mm, a non-overlapping region or space (gap) will occur such that the welding strength cannot be sufficiently ensured when the segmented piece 61 is bent toward the core side. On the other hand, if C1 exceeds 8 mm, when the segmented piece 61 is bent, the non-coated portion 43 near the bending point may be torn by stress.

[0200] Also, the height of the segmented piece 61 can be adjusted in the range of 2 to 10 mm. If C2 is less than 2 mm, a non-overlapping region or space (gap) will occur such that the welding strength cannot be sufficiently ensured when the segmented piece 61 is bent toward the core side. On the other hand, if C2 exceeds 10 mm, it is difficult to manufacture the electrode plate while maintaining the flatness of the non-coated portion uniformly in the winding direction (X direction). That is, the height of the non-coated portion is too large and undulations occur. Further, the separation pitch C3 of the segmented piece 61 can be adjusted in the range of 0.05 to 1 mm. If C3 is less than 0.05 mm, the non-coated portion 43 near the bending point may be torn by stress when the segmented piece 61 is bent. On the other hand, if C3 exceeds 1 mm, a non-overlapping region or space (gap) may occur such that the segmented pieces 61 do not overlap each other to a sufficient extent to ensure the welding strength when the segmented piece 61 is bent.

[0201] Referring to FIG. 10, a cutting portion 62 is interposed between two adjacent segment pieces 61 in the winding direction (X direction). The cutting portion 62 is a space generated by removing the non-coated portion 43. Desirably, the corner portion at the lower end of the cutting portion 62 may have a round shape (see partial enlargement). The round shape can relieve the stress applied to the lower end of the cutting portion 62 during winding of the electrode plate 60 and / or bending of the segment piece 61.

[0202] Further referring to FIG. 9, the width d of the core-side non-coated portion B1 B1 is designed by applying the condition of not blocking the cavity of the core of the electrode assembly when the segment piece 61 of the intermediate non-coated portion B2 is bent toward the core side.

[0203] In one example, the width d of the core-side non-coated portion B1 B1 can increase in proportion to the bending length of the segment piece 61 of Group 1. The bending length is the height of the segment piece 61 based on the bending point (63 in FIG. 10). Referring to FIG. 10, C4 indicates the lowest point of the position where bending is possible. The bending point can be appropriately set at the position indicated by C4 or above C4. The bending length is the length from the bending point to the upper end of the segment piece 61. Specifically, the bending point can be set at a predetermined point of the height C2 of the segment piece 61 based on C4. The predetermined point prevents the stress generated during bending of the segment piece 61 from causing physical damage to the active material layer 42 or the insulating coating layer 44, and ensures a sufficient number of layers that overlap in the radial direction when the segment piece 61 is bent in the radial direction of the electrode assembly, so that sufficient welding strength can be ensured when a current collector plate is welded to the bent region of the segment piece 61.

[0204] In a specific example, when the electrode plate 60 is used to manufacture an electrode assembly of a cylindrical cell with a form factor of 46800, the width d of the core-side non-coated portion B1 B1 can be set to 180 to 350 mm according to the diameter of the core of the electrode assembly.

[0205] In one embodiment, the width of each segment piece group can be designed to constitute the same winding turn of the electrode assembly.

[0206] Here, the winding turns can be counted with reference to the end of the core-side non-coated portion B1 when the electrode plate 60 is in a wound state.

[0207] In another modification, the width of each segmented piece group can be designed to constitute at least one or more winding turns of the electrode assembly.

[0208] Also, in another modification, the width and / or height and / or separation pitch of the segmented pieces 61 belonging to the same segmented piece group can increase or decrease gradually and / or stepwise and / or irregularly within the group.

[0209] Groups 1 to 8 are merely an example of the segmented piece groups. The number of groups, the number of segmented pieces 61 included in each group, and the width of the group can be preferably adjusted so that the segmented pieces 61 are stacked multiple times to maximize the dispersion of stress during the bending process of the non-coated portion 43 and sufficiently ensure the welding strength.

[0210] In another modification, the height of the outer peripheral side non-coated portion B3 can decrease gradually or stepwise.

[0211] Also, in another modification, the segmented structure of the intermediate non-coated portion B2 can be extended to the outer peripheral side non-coated portion B3 (see the dotted line). In this case, the outer peripheral side non-coated portion B3 can also include a plurality of segmented pieces similar to the intermediate non-coated portion B2. In this case, the segmented pieces of the outer peripheral side non-coated portion B3 may have a width and / or height and / or separation pitch larger than those of the intermediate non-coated portion B2. Optionally, the segmented structure of the outer peripheral side non-coated portion B3 can be substantially the same as the segmented piece group existing on the outermost side of the intermediate non-coated portion B2.

[0212] In a specific embodiment, when the electrode plate 60 is used to manufacture an electrode assembly of a cylindrical cell with a form factor of 46800, the width d of the core-side non-coated portion B1 B1can be 180 to 350 mm. The width of Group 1 can be 35 to 40% of the width of the non-coated portion B1 on the core side. The width of Group 2 can be 130 to 150% of the width of Group 1. The width of Group 3 can be 120 to 135% of the width of Group 2. The width of Group 4 can be 85 to 90% of the width of Group 3. The width of Group 5 can be 120 to 130% of the width of Group 4. The width of Group 6 can be 100 to 120% of the width of Group 5. The width of Group 7 can be 90 to 120% of the width of Group 6. The width of Group 8 can be 115 to 130% of the width of Group 7. The width d of the non-coated portion B3 on the outer peripheral side B3 can be the same as the width of the non-coated portion B1 on the core side, i.e., 180 to 350 mm.

[0213] The reason why the widths of Groups 1 to 8 do not show a constant increase or decrease pattern is that although the width of the segmented pieces gradually increases as it progresses from Group 1 to Group 8, the number of segmented pieces included in each group is limited to an integer. Therefore, in a specific segmented piece group, the number of segmented pieces can decrease. Thus, the width of the group can show an irregular change pattern as exemplified above as it progresses from the core side to the outer peripheral side.

[0214] That is, when the widths in the winding direction for each of the three adjacent segmented piece groups continuously in the circumferential direction of the electrode assembly are W1, W2, and W3 respectively, it may include a combination of segmented piece groups where W3 / W2 is smaller than W2 / W1.

[0215] In the above specific example, Groups 4 to 6 correspond to this. The ratio of the width of Group 5 to Group 4 is 120 to 130%, and the ratio of the width of Group 6 to Group 5 is 100 to 120%, and its value is smaller than 120 to 130%.

[0216] FIG. 11 is a plan view showing the structure of an electrode plate according to another embodiment of the present invention, and FIG. 12 is a view showing the definition of the width, height, and separation pitch of the segmented pieces according to FIG. 11.

[0217] Referring to FIG. 11, the electrode plate 70 has substantially the same configuration except that the shape of the segmented piece 61' is changed from a quadrilateral to a trapezoid as compared with FIG. 9.

[0218] FIG. 12 shows the definition of the width, height, and separation pitch of the trapezoidal segmented piece 61'.

[0219] Referring to FIG. 12, the width D1, height D2, and separation pitch D3 of the segmented piece 61' are designed to prevent the non-coated portion 43 near the bending point from being torn during the bending process of the non-coated portion 43 and to prevent abnormal deformation of the non-coated portion 43 while sufficiently increasing the number of overlapping layers of the non-coated portion 43 to ensure sufficient welding strength.

[0220] Preferably, the width D1 of the segmented piece 61' can be adjusted in the range of 1 to 8 mm. If D1 is less than 1 mm, when the segmented piece 61' is bent toward the core side, regions or spaces (gaps) where the segmented piece 61' does not overlap sufficiently to ensure sufficient welding strength may occur. On the other hand, if D1 exceeds 8 mm, when the segmented piece 61 is bent, the non-coated portion 43 near the bending point may be torn by stress. Also, the height of the segmented piece 61' can be adjusted in the range of 2 to 10 mm. If D2 is less than 2 mm, when the segmented piece 61' is bent toward the core side, regions or spaces (gaps) where the segmented piece 61' does not overlap sufficiently to ensure sufficient welding strength may occur. On the other hand, if D2 exceeds 10 mm, it is difficult to manufacture the electrode plate while maintaining the flatness of the non-coated portion 43 uniformly in the winding direction. Further, the separation pitch D3 of the segmented piece 61' can be adjusted in the range of 0.05 to 1 mm. If D3 is less than 0.05 mm, when the segmented piece 61' is bent, the non-coated portion 43 near the bending point D4 may be torn by stress. On the other hand, if D3 exceeds 1 mm, when the segmented piece 61' is bent, regions or spaces (gaps) where the segmented pieces 61' do not overlap sufficiently to ensure sufficient welding strength may occur.

[0221] Between two adjacent segment pieces 61' adjacent to the winding direction X direction, a cutting part 62 is interposed. The cutting part 62 is a space generated by removing the non-coated part 43. Desirably, the corner part at the lower end of the cutting part 62 may have a round shape (see partial enlargement). The round shape can relieve stress when the segment piece 61' is bent.

[0222] Referring to FIGS. 11 and 12, the lower inner angle θ of the plurality of segment pieces 61' may increase as it advances from the core side to the outer peripheral side. When the radius of the electrode assembly 70 increases, the curvature increases. If the lower inner angle θ of the segment piece 61' increases as the radius of the electrode assembly increases, when the segment piece 61' is bent, the stress generated in the radial direction and the circumferential direction can be relieved. Further, when the lower inner angle θ increases, when the segment piece 61' is bent, the area and the number of overlapping layers that overlap with the inner segment piece 61' also increase together, so that the welding strength can be ensured uniformly in the radial direction and the circumferential direction, and the bent surface can be formed flat.

[0223] In one example, when the electrode plate 70 is used to manufacture an electrode assembly of a cylindrical cell with a form factor of 46800, when the radius of the electrode assembly 70 increases from 4 mm to 22 mm, the inner angle of the segment piece 61' can increase step by step in the range of 60° to 85°.

[0224] In a modified example, the height of the outer peripheral non-coated part B3 may gradually or stepwise decrease as in the first and second embodiments. Further, the segmented structure of the intermediate non-coated part B2 can be extended to the outer peripheral non-coated part B3 (see the dotted line). In this case, the outer peripheral non-coated part B3 may also include a plurality of segment pieces similar to the intermediate non-coated part B2. In this case, the segment pieces of the outer peripheral non-coated part B3 may have a larger width and / or height and / or separation pitch than the intermediate non-coated part B2. Optionally, the segmented structure of the outer peripheral non-coated part B3 may be substantially the same as the group of segment pieces existing on the outermost side of the intermediate non-coated part B2.

[0225] In a specific embodiment, when the electrode plate 70 is used to manufacture an electrode assembly of a cylindrical cell having a form factor of 46,800, the width d of the non-coated portion B1 on the core side B1 can be 180 to 350 mm. The width of Group 1 can be 35 to 40% of the width of the non-coated portion B1 on the core side. The width of Group 2 can be 130 to 150% of the width of Group 1. The width of Group 3 can be 120 to 135% of the width of Group 2. The width of Group 4 can be 85 to 90% of the width of Group 3. The width of Group 5 can be 120 to 130% of the width of Group 4. The width of Group 6 can be 100 to 120% of the width of Group 5. The width of Group 7 can be 90 to 120% of the width of Group 6. The width of Group 8 can be 115 to 130% of the width of Group 7. The width d of the non-coated portion B3 on the outer peripheral side B3 can be 180 to 350 mm, the same as the width of the non-coated portion B1 on the core side.

[0226] The reason why the widths of Groups 1 to 8 do not show a constant increase or decrease pattern is that although the width of the segmented pieces gradually increases as it progresses from Group 1 to Group 8, the number of segmented pieces included in each group is limited to an integer. Therefore, in a specific segmented piece group, the number of segmented pieces can decrease. Thus, the width of the group can show an irregular change pattern as described in the above examples as it progresses from the core side to the outer peripheral side.

[0227] That is, when the widths in the winding direction for each of three continuously adjacent segmented piece groups in the circumferential direction of the electrode assembly are W1, W2, and W3 respectively, it may include a combination of segmented piece groups where W3 / W2 is smaller than W2 / W1.

[0228] In the above specific example, Groups 4 to 6 correspond to this. The ratio of the width of Group 5 to Group 4 is 120 to 130%, and the ratio of the width of Group 6 to Group 5 is 100 to 120%, and that value is smaller than 120 to 130%.

[0229] FIG. 13 is a cross-sectional view of an electrode assembly according to an embodiment of the present invention taken along the Y-axis direction (winding axis direction).

[0230] Referring to FIG. 13, the non-coated portion 43a of the electrode plate includes a core-side non-coated portion B1 adjacent to the core of the electrode assembly 100, an outer peripheral-side non-coated portion B3 adjacent to the outer peripheral surface of the electrode assembly 100, and an intermediate non-coated portion B2 interposed between the core-side non-coated portion B1 and the outer peripheral-side non-coated portion B3.

[0231] The height of the core-side non-coated portion B1 is relatively smaller than the height of the intermediate non-coated portion B2. Also, the bending length of the non-coated portion 43a located innermost in the intermediate non-coated portion B2 is the same as or smaller than the radial length R of the core-side non-coated portion B1. The bending length H corresponds to the height of the non-coated portion 43a based on the point where the non-coated portion 43a is bent (h in FIG. 10, h in FIG. 12).

[0232] Therefore, even when the intermediate non-coated portion B2 is bent, the bent portion does not block the cavity 102 of the core of the electrode assembly 100. When the cavity 102 is not blocked, there is no difficulty in the electrolyte injection process, and the efficiency of electrolyte injection is improved. Also, it is possible to easily perform the welding process between the current collector plate on the negative electrode (or positive electrode) side and the battery can (or rivet terminal) by inserting a welding jig into the cavity 102.

[0233] The height of the outer peripheral-side non-coated portion B3 is relatively smaller than the height of the intermediate non-coated portion B2. Therefore, it is possible to prevent the beading portion of the battery can from contacting the outer peripheral-side non-coated portion B3 in the process of pressurizing the beading portion near the outer peripheral-side non-coated portion B3.

[0234] In a modified example, the height of the outer peripheral-side non-coated portion B3 may gradually or stepwise decrease, unlike that shown in FIG. 13. Also, in FIG. 13, a part of the outer periphery of the intermediate non-coated portion B2 has the same height, but the height of the intermediate non-coated portion B2 may gradually or stepwise increase from the boundary between the core-side non-coated portion B1 and the intermediate non-coated portion B2 to the boundary between the intermediate non-coated portion B2 and the outer peripheral-side non-coated portion B3.

[0235] The lower non-coated portion 43b has the same structure as the upper non-coated portion 43a. In a modified example, the lower non-coated portion 43b may have a conventional electrode plate structure or the electrode plate structure of other embodiments (modified examples).

[0236] The end portions 101 of the upper non-coated portion 43a and the lower non-coated portion 43b can be bent from the outer peripheral side to the core side of the electrode assembly 100. At this time, the core-side non-coated portion B1 and the outer peripheral-side non-coated portion B3 are not substantially bent.

[0237] When the intermediate non-coated portion B2 includes a plurality of segmented pieces, it is possible to prevent the bending stress from being relaxed and the non-coated portion 43a near the bending point from being torn or abnormally deformed. Further, when the width and / or height and / or separation pitch of the segmented pieces are adjusted according to the numerical range of the above-described embodiments, the segmented pieces are overlapped multiple times to such an extent that sufficient welding strength can be ensured while being bent toward the core side, and holes (gaps) are not formed in the bending surface (the surface viewed from the Y-axis).

[0238] FIG. 14 is a cross-sectional view of an electrode assembly according to another embodiment of the present invention taken along the Y-axis direction (the winding axis direction).

[0239] Referring to FIG. 14, the electrode assembly 110 has substantially the same remaining configuration as the electrode assembly 100 of FIG. 13, except that the height of the outer peripheral-side non-coated portion B3 is substantially the same as the outermost height of the intermediate non-coated portion B2. The outer peripheral-side non-coated portion B3 may include a plurality of segmented pieces.

[0240] In the electrode assembly 110, the height of the core-side non-coated portion B1 is relatively smaller than the height of the intermediate non-coated portion B2. Also, the bending length H of the non-coated portion located innermost in the intermediate non-coated portion B2 is the same as or smaller than the radial length R of the core-side non-coated portion B1.

[0241] Therefore, even if the intermediate non-coated portion B2 is bent, the bent portion does not block the cavity 112 of the core of the electrode assembly 110. When the cavity 112 is not blocked, there is no difficulty in the electrolyte injection process, and the efficiency of electrolyte injection is improved. In addition, it is possible to easily perform the welding process between the current collector plate on the negative electrode (or positive electrode) side and the battery can (or rivet terminal) by inserting a welding jig from the cavity 112.

[0242] In a modified example, the structure in which the height of the intermediate non-coated portion B2 gradually or stepwise increases from the core side toward the outer peripheral side can be extended to the outer peripheral non-coated portion B3. In this case, the height of the non-coated portion 43a can gradually or stepwise increase from the boundary between the core-side non-coated portion B1 and the intermediate non-coated portion B2 to the outer surface of the electrode assembly 110 on the difference outer side.

[0243] The lower non-coated portion 43b has the same structure as the upper non-coated portion 43a. In a modified example, the lower non-coated portion 43b can have the structure of a conventional electrode plate or the electrode plate of other embodiments (modified examples).

[0244] The end portions 111 of the upper non-coated portion 43a and the lower non-coated portion 43b can be bent from the outer peripheral side to the core side of the electrode assembly 110. At this time, the core-side non-coated portion B1 is not substantially bent.

[0245] When the intermediate non-coated portion B2 and the outer peripheral non-coated portion B3 include a plurality of segmented pieces, the bending stress can be relaxed to prevent the non-coated portions 43a and 43b near the bending point from being torn or abnormally deformed. In addition, when the width and / or height and / or separation pitch of the segmented pieces are adjusted according to the numerical ranges of the above-described embodiments, the segmented pieces are overlapped multiple times to such an extent that sufficient welding strength can be ensured while being bent toward the core side, and no holes (gaps) are formed in the bending surface (the surface viewed from the Y axis).

[0246] FIG. 15 is a diagram schematically showing the configuration of a battery pack according to an embodiment of the present invention.

[0247] Referring to FIG. 15, a battery pack 800 according to an embodiment of the present invention includes an assembly in which cylindrical battery cells 10 are electrically connected and a pack housing 810 that houses the same. The cylindrical battery cells 10 are the battery cells according to the above-described embodiments. In the drawings, for the sake of illustration, illustration of components such as bus bars, cooling units, and external terminals for the electrical connection of the cylindrical battery cells 10 is omitted.

[0248] The battery pack 800 can be mounted on an automobile 900. The automobile 900 is an example and can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile 900 includes a four-wheel vehicle or a two-wheel vehicle.

[0249] FIG. 16 is a diagram for explaining an automobile including the battery pack of FIG. 15.

[0250] Referring to FIG. 16, an automobile 900 according to an embodiment of the present invention includes a battery pack 800 according to an embodiment of the present invention. The automobile 900 operates by receiving power from the battery pack 800 according to an embodiment of the present invention.

[0251] As described above, the present invention has been described with reference to limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by those having ordinary knowledge in the technical field to which the present invention pertains.

Description of Reference Numerals

[0252] 10 Cylindrical battery cell 21 Beading portion 30 Current collector plate 42 Active material layer 43 Non-coated portion 43a Upper non-coated portion 43b Lower non-coated portion 44 Insulating coating layer 60 Electrode plate 61, 61’ Trapezoidal segmented piece 62 Cutting portion 70 Electrode plate 100 Electrode assembly 101 End part 102 Cavity 110 First non-coated part 111 End part 112 Cavity 120 Second non-coated part 200 Battery can 210 Closing part 211 Through hole 220 Open part 230 Cap plate 231 Vent notch 240 Beading part 250 Crimping part 260 Sealing gasket 300 Current collector plate 310 Edge part 320 Non-coated part joint 330 Terminal joint 340 Connecting part 350 Fuse part 351 Notch 352 Through hole 353 Tape 400 Cell terminal 410 Terminal insertion part 500 Insulating tape 600 Insulator 700 Lower current collector plate 800 Battery pack 810 Pack housing

Claims

1. In a jelly roll type electrode assembly having a structure in which a sheet-like first electrode plate, a second electrode plate, and a separator interposed therebetween are wound in one direction, the first electrode plate includes a first non-coated portion where an active material layer is not coated at a long side end portion, and the first non-coated portion is exposed outside the separator while forming a plurality of winding turns with reference to the center of the electrode assembly, and an electrode assembly that is used as an electrode tab by itself, An open portion in which the electrode assembly is housed, and a battery can having a partial closing portion on the side opposite to the open portion, and A current collector plate that is electrically connected to the first non-coated portion of the first electrode plate and has a fuse portion formed therein that breaks when an overcurrent flows, A cell terminal that is connected to the current collector plate through a through hole in the closing portion of the battery can, including a cylindrical battery cell.

2. The cylindrical battery cell according to claim 1, wherein a flat portion parallel to the inner surface of the closing portion of the battery can is formed at least partially on the bottom surface of the cell terminal, and the current collector plate is coupled to the flat portion of the cell terminal.

3. The current collector plate is The cylindrical battery cell according to claim 1 or 2, characterized in that it is coupled to a coupling surface formed by bending an end portion of the first non-coated portion.

4. The electrode assembly includes a welding target region along the radial direction of the electrode assembly, The cylindrical battery cell according to claim 1 or 2, characterized in that the current collector plate is coupled to the first non-coated portion within the welding target region.

5. The current collector plate is An edge portion disposed on the upper portion of the electrode assembly, A non-coated portion coupling portion that extends inward from the edge portion and is coupled to the first non-coated portion, A terminal coupling portion that is separated from the non-coated portion coupling portion and is coupled to the cell terminal, Including a connecting portion that extends inward from the edge portion, is connected to the terminal coupling portion, and in which the fuse portion is formed, The cylindrical battery cell according to claim 1 or 2, characterized in that the fuse portion has a greater resistance than other regions under the condition that the same current flows.

6. The cylindrical battery cell according to claim 5, characterized in that the edge portion has a rim form in which at least a part of the inner region is vacant.

7. The cylindrical battery cell according to claim 5, characterized in that the non-coated portion coupling portion and the terminal coupling portion are electrically connected through the edge portion.

8. The cylindrical battery cell according to claim 5, wherein the terminal connection portion is located at the center of the inner space of the edge portion.

9. The cylindrical battery cell according to claim 5, wherein the terminal connection portion has a diameter that is 100% to 110% of the diameter of the cavity existing in the core of the electrode assembly.

10. The cylindrical battery cell according to claim 5, wherein the fuse portion is at least one notch formed in the connection portion.

11. The cylindrical battery cell according to claim 10, wherein the notch is formed at an end in the width direction of the connection portion, on the upper surface of the connection portion, or on the lower surface of the connection portion.

12. The cylindrical battery cell according to claim 11, wherein the notch is formed to be recessed inward of the connection portion in a direction that gradually or continuously reduces the width or thickness of the connection portion.

13. The cylindrical battery cell according to claim 12, wherein the minimum width of the fuse portion is 0.5 mm to 4.0 mm.

14. The cylindrical battery cell according to claim 5, wherein the fuse portion is at least one through hole formed in the connection portion.

15. The cylindrical battery cell according to claim 14, wherein the through hole has a maximum width of 0.2 mm to 6 mm.

16. The cylindrical battery cell according to claim 5, wherein the fuse portion is wound with a tape.

17. The cylindrical battery cell according to claim 16, wherein the tape contains a polyimide material.

18. The cylindrical battery cell according to claim 5, wherein the fuse portion is formed in the connection portion so as to be separated from the center of the electrode assembly by a distance of 40% to 90% of its maximum radius.

19. The cylindrical battery cell according to claim 1 or 2, wherein at least a partial section of the first non-coated portion is divided into a plurality of segmented pieces along the winding direction of the electrode assembly.

20. The cylindrical battery cell according to claim 19, wherein at least a part of the plurality of segmented pieces is bent in the radial direction of the electrode assembly.

21. The cylindrical battery cell according to claim 20, wherein at least a part of the plurality of segmented pieces are superimposed multiple times along the radial direction of the electrode assembly.

22. The rest of the plurality of segmented pieces are not bent, The cylindrical battery cell according to claim 20, wherein the fuse portion is displaced from the non-bent segmented pieces among the plurality of segmented pieces and is located above the bent segmented pieces among the plurality of segmented pieces.

23. The rest of the plurality of segmented pieces are cut, The cylindrical battery cell according to claim 20, wherein the fuse portion is displaced from the cut segmented pieces among the plurality of segmented pieces and is located above the bent segmented pieces among the plurality of segmented pieces.

24. The welding pattern depicted by the welding beads formed on one surface of the terminal connection portion of the current collector plate is depicted in a form surrounding the central portion of the bottom surface of the cell terminal, according to the cylindrical battery cell of claim 5.

25. The cylindrical battery cell according to claim 24, wherein the welding pattern is formed continuously or discontinuously.

26. The cylindrical battery cell according to claim 5, wherein the tensile force of the welded portion formed between the terminal connection portion of the current collector plate and the bottom surface of the cell terminal is 2 kgf or more.

27. The cylindrical battery cell according to claim 26, wherein the converted diameter of the welding pattern depicted by the welding beads formed on one surface of the terminal connection portion of the current collector plate is 2 mm or more.

28. The cylindrical battery cell according to claim 1 or 2, further comprising a cap plate configured to seal the open portion of the battery can.

29. The cylindrical battery cell according to claim 28, wherein the cap plate is electrically separated from the electrode assembly and provided non-polar.

30. A through hole is formed in the closing portion, The cylindrical battery cell according to claim 28, wherein the cell terminal is coupled to the through hole.

31. The cylindrical battery cell according to claim 30, further comprising an insulator interposed between the closing portion and the current collector plate.

32. The cylindrical battery cell according to claim 31, wherein the insulator contains an insulating polymer material.

33. The cylindrical battery cell according to claim 31, wherein the insulator is made of an elastic material.

34. The cylindrical battery cell according to claim 31, wherein the insulator has a central hole with a preset diameter at the center.

35. The cylindrical battery cell according to claim 31, wherein the insulator has a thickness corresponding to the distance between the inner surface of the closed portion of the battery can and the current collector plate.

36. The cylindrical battery cell according to claim 31, wherein the upper surface of the insulator contacts the inner surface of the closed portion of the battery can, and the lower surface of the insulator contacts the upper surface of the current collector plate.

37. The cell terminal includes a terminal insertion portion, The cylindrical battery cell according to claim 34, wherein the terminal insertion portion is inserted into the battery can from the through hole.

38. The cylindrical battery cell according to claim 37, wherein the peripheral edge of the lower part of the terminal insertion portion of the cell terminal is riveted toward the inner surface of the upper end of the battery can and fixed to the through hole.

39. The cylindrical battery cell according to claim 37, wherein the diameter of the central hole of the insulator is larger than or equal to the diameter of the terminal insertion portion.

40. The cylindrical battery cell according to claim 37, wherein the terminal insertion portion of the cell terminal penetrates the central hole of the insulator.

41. The cylindrical battery cell according to claim 37, wherein the terminal insertion portion of the cell terminal penetrates the central hole of the insulator and is electrically coupled to the current collector plate.

42. Including a sealing gasket interposed between the peripheral edge of the cap plate and the open portion of the battery can, The battery can includes a beading portion press-fitted into the inside of the battery can in a region adjacent to the open portion, The cylindrical battery cell according to claim 28, wherein the battery can includes a crimping portion that extends inward of the battery can and is bent to surround and fix the peripheral edge of the cap plate together with the sealing gasket.

43. The cylindrical battery cell according to claim 42, wherein the crimping portion is formed below the battery can with reference to the arrangement state of the battery can.

44. The cylindrical battery cell according to claim 28, wherein the cap plate includes a vent notch that ruptures when the internal pressure of the battery can exceeds a critical value.

45. The cylindrical battery cell according to claim 44, wherein the vent notch is formed on both surfaces of the cap plate and is formed in at least one pattern among a continuous circular pattern, a discontinuous circular pattern, and a linear pattern on the surface of the cap plate.

46. The cylindrical battery cell according to claim 44, wherein the vent notch is formed at the lower end of the battery can with reference to the arrangement state of the battery can, and when the vent notch ruptures, the gas inside the battery can is discharged from the lower end of the battery can.

47. The cylindrical battery cell according to claim 42, further comprising a lower current collector plate coupled to the lower part of the electrode assembly.

48. The cylindrical battery cell according to claim 47, wherein at least a part of the edge of the lower current collector plate is electrically coupled to the beading portion, and at least a part of the remaining portion excluding the edge is electrically connected to the second non-coated portion of the second electrode plate.

49. The cylindrical battery cell according to claim 48, wherein at least a part of the end of the lower current collector plate is electrically coupled to the surface adjacent to the crimping portion among the upper and lower surfaces of the beading portion.

50. The cylindrical battery cell according to claim 49, wherein the lower current collector plate and the beading portion are laser welded.

51. A battery pack including at least one cylindrical battery cell according to claim 1 or 2.

52. An automobile including at least one battery pack according to claim 51.

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