Electrode terminal crimp structure, battery cell including same, battery pack, and automobile

Abstract

Riveting structure of electrode terminal, battery cell including the same, battery pack, and automobile. The present invention provides a riveting structure of electrode terminal, a cylindrical battery cell including the same, a battery pack, and an automobile, the riveting structure of electrode terminal including: a battery can having one side opened; an electrode terminal riveted through a through-hole formed in a bottom of the battery can; and a gasket provided between the electrode terminal and an outer diameter of the through-hole, the gasket including a fluororesin.

Description

Technical Field

[0001] This application claims the benefit of Korean Patent Application No. 10-2021-0165315 filed with the Korean Patent Office on November 26, 2021; Korean Patent Application No. 10-2022-0088341 filed with the Korean Patent Office on July 18, 2022; and International Application No. PCT / KR2022 / 010446 filed with the Korean Patent Office on July 18, 2022. All disclosures in the corresponding Korean patent applications and international application documents are included in this specification.

[0002] This invention relates to a riveting structure for electrode terminals and to battery cells, battery packs, and automobiles that include the same. Background Technology

[0003] Secondary batteries, which are highly adaptable to various product groups and have high energy density and other electrical properties, are not only used in portable devices, but also widely used in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electric drive sources.

[0004] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also the advantage of not producing any byproducts when using energy. Therefore, they are attracting much attention as a new energy source that is both environmentally friendly and improves energy efficiency.

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

[0006] In addition, types of secondary battery cells include cylindrical, prismatic, and pouch-shaped battery cells. The aforementioned battery cell can be a cylindrical battery cell. The aforementioned battery cell consists of an electrode assembly formed by sandwiching an insulator, i.e., a separator membrane, between the anode and cathode and rolling it up to form a jelly roll. This assembly, along with the electrolyte, is then embedded inside a battery can to form a battery. Furthermore, strip-shaped electrode tabs are connected to the uncoated portions of both the anode and cathode, electrically connecting the electrode assembly to the exposed electrode terminals. For reference, the anode electrode terminal is a cover plate of a sealing body that seals the opening of the battery can, and the cathode electrode terminal is the battery can itself.

[0007] However, in conventional battery cells with such a structure, the current is concentrated on the strip-shaped electrode tabs that are connected to the uncoated anode and / or uncoated cathode, resulting in high resistance, excessive heat generation, and poor current collection efficiency.

[0008] In small cylindrical battery cells with a form factor of 18650 or 21700, resistance and heat generation are not major issues. However, when the form factor is increased to apply cylindrical battery cells to electric vehicles, more heat is generated around the electrode tabs during rapid charging, leading to the possibility of fires in the cylindrical battery cells.

[0009] To address this issue, a battery cell with the following structure (so-called a tabless battery cell) has been disclosed: an uncoated anode portion and an uncoated cathode portion are respectively provided at the upper and lower ends of a jelly roll-type electrode assembly, and a current collector plate is welded to such uncoated portions to improve current collection efficiency.

[0010] Figures 1 to 3 This is a diagram illustrating the manufacturing process of a tabless battery cell. Figure 1 The structure of the electrode plate is shown. Figure 2 The electrode plate winding process is shown. Figure 3 The process of welding a current collector to the bent surface of the uncoated part is shown. Figure 4 This is a cross-sectional view of a tabless battery cell cut along the length direction Y.

[0011] Reference Figures 1 to 4 The anode plate 10 and the cathode plate 11 have a structure in which an active material 21 is coated on the sheet-like current collector 20, and an uncoated portion 22 is included on one of the long sides along the winding direction X.

[0012] like Figure 2 As shown, electrode assembly A is manufactured by sequentially stacking an anode plate 10 and a cathode plate 11 together with two separation membranes 12 and then winding them in one direction X. At this time, the uncoated portions of the anode plate 10 and the cathode plate 11 are arranged in opposite directions.

[0013] After the winding process, the uncoated portion 10a of the anode plate 10 and the uncoated portion 11a of the cathode plate 11 are bent toward the core. Thereafter, current collectors 30 and 31 are welded to the uncoated portions 10a and 11a respectively to form a bond.

[0014] No other electrode tabs are attached to the uncoated anode portion 10a and the uncoated cathode portion 11a. The current collectors 30 and 31 are connected to external electrode terminals. The current path is formed with a large cross-sectional area along the winding axis of the electrode assembly A (refer to the arrow), thus having the advantage of reducing the resistance of the battery cell. This is because resistance is inversely proportional to the cross-sectional area of ​​the current flow path.

[0015] However, if the shape factor of the cylindrical battery cell increases and the charging current increases during rapid charging, the heat generation problem will reappear in the tabless battery cell.

[0016] Specifically, such as Figure 4 As shown, a conventional tabless battery cell 40 includes a battery canister 41 and a sealing body 42. The sealing body 42 includes a cover plate 42a, a sealing gasket 42b, and a connecting plate 42c. The sealing gasket 42b surrounds the edge of the cover plate 42a and is fixed by a crimping portion 43. In addition, the electrode assembly A is fixed inside the battery canister 41 by a beading portion 44 to prevent up and down movement.

[0017] Typically, the anode terminal is the cover plate 42a of the sealing body 42, and the cathode terminal is the battery can 41. Therefore, the current collector 30, which is attached to the uncoated portion 10a of the anode plate 10, is electrically connected to the connecting plate 42c attached to the cover plate 42a via a strip-shaped lead 45. Additionally, the current collector 31, which is attached to the uncoated portion 11a of the cathode plate 11, is electrically connected to the bottom of the battery can 41. An insulator 46 covers the current collector 30 to prevent the battery can 41 and the uncoated portion 10a of the anode plate 10, which have different polarities, from contacting each other and causing a short circuit.

[0018] A strip-shaped lead 45 is used when connecting the current collector 30 to the connecting plate 42c. The lead 45 is attached independently to the current collector 30 or formed integrally with the current collector 30. However, the lead 45 is a thin strip, so its cross-sectional area is small and more heat is generated when a rapid charging current flows. In addition, the excessive heat generated on the lead 45 is transferred to the electrode assembly A side, causing the separation membrane 12 to shrink, which is the main cause of thermal runaway, namely internal short circuit.

[0019] The lead wire 45 occupies a considerable amount of space within the battery canister 41. Therefore, the space efficiency of the battery cell 40, including the lead wire 45, is low, thus limiting the potential for increasing energy density.

[0020] Furthermore, in order to connect the conventional tabless battery cells 40 in series and / or parallel, busbar components need to be connected to the cover plate 42a of the sealing body 42 and the bottom surface of the battery tank 41, thus reducing space efficiency. Battery packs in electric vehicles comprise hundreds of battery cells 40. Therefore, the inefficiency of the electrical wiring is quite troublesome during the assembly process of the electric vehicle and the maintenance of the battery pack. Summary of the Invention

[0021] The problem that the invention aims to solve

[0022] This invention was developed in the context of the aforementioned prior art. The purpose of this invention is to improve the electrode terminal structure of the battery cell, thereby increasing the space efficiency within the battery can, reducing the internal resistance of the battery cell, and increasing the energy density.

[0023] Another technical challenge of this invention is to improve the electrode terminal structure of the battery cell and increase the cross-sectional area of ​​the current channel, thereby improving the internal heat generation problem during rapid charging.

[0024] Another technical objective of the present invention is to provide a battery cell with an improved structure for performing electrical wiring operations for series and / or parallel connection of battery cells on one side of the battery cell.

[0025] Another technical objective of the present invention is to provide a battery pack manufactured using battery cells with an improved structure and an automobile including the same.

[0026] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems, and those skilled in the art can clearly understand other problems not mentioned herein from the following description of the invention.

[0027] Methods for solving problems

[0028] One embodiment of the present invention provides a riveting structure for electrode terminals, comprising: a battery can with one side open; an electrode terminal riveted through a through hole formed in the bottom of the battery can; and a gasket disposed between the electrode terminal and the outer diameter of the through hole.

[0029] The electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion extending around the outer surface of the main body portion exposed through the outer surface of the bottom; and an inner flange portion extending around the other side of the main body portion exposed through the inner surface of the bottom toward the inner surface.

[0030] The aforementioned gaskets include fluoropolymers.

[0031] One embodiment of the present invention provides a riveting structure for electrode terminals, comprising: a battery can with one side open; an electrode terminal riveted through a through hole formed in the bottom of the battery can; and a gasket disposed between the electrode terminal and the outer diameter of the through hole.

[0032] The electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion extending around the outer surface of the main body portion exposed through the outer surface of the bottom; and an inner flange portion extending around the other side of the main body portion exposed through the inner surface of the bottom toward the inner surface.

[0033] The aforementioned gasket includes: an outer gasket portion sandwiched between the outer flange portion and the outer surface of the bottom; and an inner gasket portion sandwiched between the inner flange portion and the inner surface of the bottom.

[0034] The thickness variation rate of the aforementioned external gasket portion satisfies the following equation 1:

[0035] [Formula 1]

[0036] 0%≤[(X1-X2) / X1]×100(%)≤10%

[0037] In Formula 1 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 100°C for 10 minutes.

[0038] Another embodiment of the present invention provides a battery cell comprising: an electrode assembly formed by winding a sheet-like first electrode plate and a second electrode plate with a separator sandwiched between them, and including uncoated portions of the first electrode plate and the second electrode plate extending from both ends; a riveting structure for electrode terminals according to the embodiment of the present invention; and a sealing body.

[0039] The aforementioned electrode assembly is housed inside the aforementioned battery can, the aforementioned first electrode plate is electrically connected to the aforementioned battery can, and the aforementioned second electrode plate is electrically connected to the aforementioned electrode terminals.

[0040] The aforementioned sealing body seals the open end of the aforementioned battery canister, thereby achieving insulation between the sealing body and the battery canister.

[0041] Another embodiment of the present invention provides a battery pack and a vehicle comprising at least one battery cell as described above.

[0042] Invention Effects

[0043] According to one aspect of the present invention, the electrode terminal structure of the battery cell can be improved to increase the space efficiency within the battery canister, thereby reducing the internal resistance of the battery cell and increasing the energy density.

[0044] In conventional tabless battery cells, a sealing gasket is placed between the anode terminal (the cover plate) and the cathode terminal (the battery canister) to prevent short circuits. When conventional PP (Polypropylene) or PBT (Polybutylene Terephthalate) is used as the material for the sealing gasket, it has a low melting point and therefore can melt and cause a short circuit as the energy density of the battery cell increases.

[0045] According to another aspect of the invention, a gasket comprising fluororesin is provided to embody the electrode terminal structure of the battery cell as described above, thereby preventing the gasket from melting between the hot electrode terminals and the battery canister at higher temperatures during assessment of external short circuits or in the event of an increase in the energy density of the battery cell, thus preventing a short circuit.

[0046] According to another aspect of the invention, the electrode terminal structure of the battery cell can be improved to increase the cross-sectional area of ​​the current channel, thereby improving the internal heat generation problem during rapid charging.

[0047] According to another aspect of the invention, electrical wiring for connecting battery cells in series and / or in parallel can be performed on one side of the battery cell.

[0048] According to another aspect of the invention, a battery pack manufactured using battery cells with an improved structure and an automobile including the same can be provided. Attached Figure Description

[0049] The following drawings in this specification illustrate preferred embodiments of the invention and serve to further explain the technical concept of the invention together with the detailed description of the invention that follows. Therefore, the invention should not be interpreted as limited to the scope shown in these drawings.

[0050] Figure 1 This is a top view showing the structure of the electrode plates used in conventional tabless battery cells.

[0051] Figure 2 This diagram illustrates the winding process of electrode assemblies included in conventional tabless battery cells.

[0052] Figure 3 It is shown Figure 2 A diagram showing the process of welding a current collector plate to the bent surface of the uncoated part in the electrode assembly.

[0053] Figure 4 This is a cross-sectional view of a traditional tabless battery cell cut along the length direction Y.

[0054] Figure 5This is a cross-sectional view showing the riveting structure of the electrode terminals according to an embodiment of the present invention.

[0055] Figure 6 Is Figure 5 Enlarged cross-sectional view of the part indicated by the dashed circle.

[0056] Figure 7 This is a cross-sectional view of a battery cell of one embodiment of the present invention cut along the length direction Y.

[0057] Figure 8 This is a top view illustrating an exemplary embodiment of the electrode plate structure of the present invention.

[0058] Figure 9 This is a cross-sectional view of an electrode assembly formed by cutting the uncoated portion of the electrode plate of an embodiment of the present invention along the length direction Y and applying the cutting structure to the first electrode plate and the second electrode plate.

[0059] Figure 10 This is a cross-sectional view of the electrode assembly with the uncoated portion bent along the length direction Y, according to an embodiment of the present invention.

[0060] Figure 11 This is a diagram illustrating a schematic structure of a battery pack including battery cells according to embodiments of the present invention.

[0061] Figure 12 This is a diagram illustrating a schematic structure of a car including a battery pack according to an embodiment of the present invention.

[0062] Figure 13 This is a diagram illustrating the phenomenon of gasket melting in the riveting structure of the electrode terminals in the case of the gasket in the comparative example of the present invention.

[0063] Figure 14 This is a diagram illustrating the phenomenon where the gasket does not melt in the riveting structure of the electrode terminals in the case of a gasket including a fluororesin in an embodiment of the present invention.

[0064] Figure 15 This is a diagram showing a cross-section of the riveting structure of the electrode terminals of an embodiment of the present invention, cut along the length Y direction of the battery cell.

[0065] (Symbol Explanation)

[0066] 10: Anode plate; 11: Cathode plate; 10a: Uncoated portion of the anode plate; 11a: Uncoated portion of the cathode plate; 12: Separation membrane; 20: Current collector; 21: Active material; 22: Uncoated portion; 30, 31: Current collector plates; 40: Tablet-less battery cell; 41: Battery canister; 42: Sealing body; 42a: Cover plate; 42b: Sealing gasket; 42c: Connecting plate; 43: Crimping part; 44: Crimped part; 45: Lead wire; 46: Insulator; A: Electrode Component; 50: Electrode terminal; 50a: Main body; 50b: Outer flange; 50c: Inner flange; 50d: Flat portion; 51: Cylindrical battery can with one side open; 51a: Inner circumferential surface of the battery can side wall; 52: Bottom; 52a: Outer surface; 52b: Inner surface; 53: Through hole; 54: Gasket; 54a: Outer gasket portion; 54aT: Thickness of the outer gasket portion; 54b: Inner gasket portion; 55: Groove portion; 55a: Flat portion 55b: Inclined surface of the inner flange; 56: Inner edge of the through hole; 57: Opposite surface opposite to the inner flange; 70: Battery cell; 71: Electrode assembly; 72: Uncoated portion of the first electrode plate; 73: Uncoated portion of the second electrode plate; 74: Sealing body; 74a: Cover plate; 74b: Sealing gasket; 75: Pressing portion; 76: Crimped portion; 76a: Inner peripheral surface of the crimped portion; 77: Vent; 78: First current collector; 78a: The first current collector 79: Edge of a current collector plate; 79a: Central section; 80: Core; 80': Insulating cover; 80a: Welding hole; 90: Electrode plate; 91: Current collector; 92: Active material layer; 93: Uncoated section; 93': Uncoated section on the core side; 93a: Slice; 94: Insulating coating; 100: Electrode assembly; 101: Bending section; 102: Bending surface; 200: Battery pack; 201: Cylindrical battery cell; 202: Pack casing. Detailed Implementation

[0067] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Before proceeding, the terms and words used in this specification and claims should not be limited to their ordinary or dictionary meanings. Given the principle that inventors may appropriately define terms and concepts in order to best illustrate their invention, they should be interpreted as meanings and concepts consistent with the technical concept of the present invention.

[0068] Therefore, the embodiments described in this specification and the structures shown in the accompanying drawings are only one of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. It should be understood that at the time of filing this application, there may be various equivalents and multiple modifications that can replace these.

[0069] Furthermore, to aid in understanding the invention, the dimensions of some components in the drawings are sometimes exaggerated, rather than shown to actual scale. Also, in different embodiments, the same symbols are used for the same components.

[0070] One embodiment of the present invention provides a riveting structure for electrode terminals, comprising: a battery can with one side open; an electrode terminal riveted through a through hole formed in the bottom of the battery can; and a gasket disposed between the electrode terminal and the outer diameter of the through hole.

[0071] The electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion extending around the outer surface of the main body portion exposed through the outer surface of the bottom; and an inner flange portion extending around the other side of the main body portion exposed through the inner surface of the bottom toward the inner surface.

[0072] The aforementioned gaskets include fluoropolymers.

[0073] The battery cell in an embodiment of the present invention includes electrode terminals riveted to the bottom of the battery can.

[0074] Figure 5 This is a cross-sectional view showing the riveting structure of the electrode terminal 50 according to an embodiment of the present invention. Figure 6 This is an enlarged cross-sectional view of the part indicated by the dashed circle.

[0075] Reference Figure 5 and Figure 6 The riveting structure of the electrode terminal 50 in the embodiment includes: a cylindrical battery can 51 with one side open; an electrode terminal 50 riveted through a through hole 53 formed in the bottom 52 of the battery can 51; and a gasket 54 disposed between the electrode terminal 50 and the outer diameter of the through hole 53.

[0076] The battery canister 51 is made of a conductive metal. In one example, the battery canister 51 is made of steel, but the invention is not limited thereto.

[0077] The electrode terminal 50 is made of a conductive metal. In one example, the electrode terminal 50 is made of aluminum, but the invention is not limited thereto.

[0078] Preferably, the electrode terminal 50 includes: a main body portion 50a inserted into the through hole 53; an outer flange portion 50b extending around one side of the main body portion 50a exposed through the outer surface 52a of the bottom 52 of the battery can 51 along the outer surface 52a; and an inner flange portion 50c extending around the other side of the main body portion 50a exposed through the inner surface 52b of the bottom 52 of the battery can 51 toward the inner surface 52b.

[0079] Gasket 54 comprises a fluororesin. The fluororesin is composed of an insulating and / or elastic polymer resin. In one example, the fluororesin includes one or more resins selected from the group consisting of PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene), but the invention is not limited thereto.

[0080] In one example, the melting point of the fluoropolymer is about 280°C or higher, preferably about 290°C or higher, and more preferably about 300°C or higher. When the melting point of the fluoropolymer meets the above range, the gasket will not melt even if the energy density of the battery cell increases, thus preventing short circuits.

[0081] One embodiment of the present invention provides a riveting structure for electrode terminals, comprising: a battery can with one side open; an electrode terminal riveted through a through hole formed in the bottom of the battery can; and a gasket disposed between the electrode terminal and the outer diameter of the through hole.

[0082] The electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion extending around the outer surface of the main body portion exposed through the outer surface of the bottom; and an inner flange portion extending around the other side of the main body portion exposed through the inner surface of the bottom toward the inner surface.

[0083] The aforementioned gasket includes: an outer gasket portion sandwiched between the outer flange portion and the outer surface of the bottom; and an inner gasket portion sandwiched between the inner flange portion and the inner surface of the bottom.

[0084] The thickness variation rate of the aforementioned external gasket satisfies Equation 1 below.

[0085] [Formula 1]

[0086] 0%≤[(X1-X2) / X1]×100(%)≤10%

[0087] In Formula 1 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 100°C for 10 minutes.

[0088] According to one aspect, the gasket 54 includes: an outer gasket portion 54a sandwiched between an outer flange portion 50b and an outer surface 52a of the bottom 52 of the battery can 51; and an inner gasket portion 54b sandwiched between an inner flange portion 50c and an inner surface 52b of the bottom 52 of the battery can 51.

[0089] According to an additional embodiment of the present invention, the thickness variation rate of the outer gasket portion 54a satisfies the following formula 1.

[0090] [Formula 1]

[0091] 0%≤[(X1-X2) / X1]×100(%)≤10%

[0092] In Formula 1 above, X1 is the thickness 54aT of the outer gasket portion at room temperature, and X2 is the thickness 54aT of the outer gasket portion after being placed at 100°C for 10 minutes.

[0093] The above-mentioned normal temperature refers to a temperature selected between 20°C and 25°C, for example, it can be 21°C to 24°C, 22°C to 23°C, or 23°C.

[0094] The thickness 54aT of the aforementioned external gasket portion refers to the thickness in the direction perpendicular to the outer surface 52a of the bottom of the aforementioned battery can. This thickness can be measured by taking an image of the cross-section of the battery cell 201 cut along the length direction Y using a 3D shape measuring instrument.

[0095] Figure 15 This is a cross-sectional view showing a cut of the riveting structure of the electrode terminals of an embodiment of the present invention along the length direction Y of the battery cell 201.

[0096] Reference Figure 15 In the riveting structure of the electrode terminal 50 including the aforementioned outer gasket portion 54a, the thickness 54aT of the outer gasket portion is measured by measuring the cross-section of the battery cell 201 including the riveting structure along the length direction Y using a 3D shape measuring instrument. At this time, the thickness 54aT of the outer gasket portion can be the thinnest part among the measured thicknesses.

[0097] The thickness change rate of the outer gasket portion 54a refers to the thickness change of the outer gasket portion 54a due to temperature and time. In Formula 1 above, the thickness change rate of the outer gasket portion 54a is preferably 10% or less.

[0098] In Formula 1 above, the thickness variation rate of the outer gasket portion 54a can be 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. The thickness variation rate of the outer gasket portion 54a can be 0% or more, 0.5% or more, 1% or more, 1.5% or more, 2%, 2.5% or more, or 3% or more. When the thickness variation rate of the outer gasket portion 54a meets the above ranges, a gasket 54 that does not melt in the riveting structure of the electrode terminals is provided to prevent short circuits caused by the gasket melting between the electrode terminals and the battery canister.

[0099] According to one embodiment of the present invention, a riveting structure for electrode terminals is provided, wherein the gasket 54 comprises fluororesin. The gasket 54 comprising fluororesin minimizes the thickness variation of the outer gasket portion 54a, thereby preventing short circuits caused by the gasket melting between the electrode terminal and the battery canister.

[0100] According to one embodiment of the present invention, the gasket 54 includes: an outer gasket portion 54a sandwiched between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b sandwiched between the inner flange portion 50c and the inner surface of the bottom.

[0101] The thickness variation rate of the external gasket 54a satisfies Equation 2 below.

[0102] [Equation 2]

[0103] 0%≤[(X1-X2) / X1]×100(%)≤10%

[0104] In Formula 2 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 150°C for 10 minutes.

[0105] As described above, the thickness change rate of the outer gasket portion 54a represents the thickness change of the outer gasket portion 54a due to temperature. The gasket 54 includes a fluoropolymer resin, thereby minimizing the thickness change of the outer gasket portion 54a.

[0106] In Formula 2 above, the thickness variation rate of the outer gasket portion 54a can be 10% or less, 9.5% or less, 9% or less, 8.5%, 8% or less, 7.5% or less, or 7% or less. The thickness variation rate of the outer gasket portion 54a can be 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more. When the thickness variation rate of the outer gasket portion 54a meets the above ranges, a gasket 54 that does not melt in the riveting structure of the electrode terminal is provided, thereby preventing short circuits caused by the gasket melting between the electrode terminal and the battery canister.

[0107] According to one embodiment of the present invention, the gasket 54 includes: an outer gasket portion 54a sandwiched between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b sandwiched between the inner flange portion 50c and the inner surface of the bottom.

[0108] The thickness variation rate of the external gasket portion 54a satisfies the following equation 3.

[0109] [Formula 3]

[0110] 0%≤[(X1-X2) / X1]×100(%)≤10%

[0111] In Formula 3 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 230°C for 30 minutes.

[0112] As described above, the thickness change rate of the outer gasket portion 54a refers to the thickness change of the outer gasket portion 54a due to temperature. The gasket 54 includes a fluoropolymer resin, thereby minimizing the thickness change of the outer gasket portion 54a.

[0113] In Equation 3 above, the thickness variation rate of the outer gasket portion 54a can be 10% or less, 9.7% or less, 9.5% or less, 9.3% or less, or 9% or less. The thickness variation rate of the outer gasket portion 54a can be 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, or 7% or more. When the thickness variation rate of the outer gasket portion 54a meets the above ranges, a gasket 54 that does not melt in the riveting structure of the electrode terminal is provided to prevent short circuits caused by the gasket melting between the electrode terminal and the battery canister.

[0114] There is a difference between [Equation 1] to [Equation 3] regarding the thickness variation rate of the external gasket portion 54a including the aforementioned fluororesin and the thickness variation rate of the external gasket portion excluding fluororesin, as shown in Table 1 below.

[0115] [Table 1]

[0116]

[0117] Referring to Table 1 above, Formulas 1 to 3 relate to the thickness variation rate of the external gasket portion 54a, which includes fluoropolymer resin and comprises PFA (Perfluoroalkoxy) and PTFE (Polytetrafluoroethylene). When Formulas 1 to 3 satisfy the above range, the thickness variation rate of the external gasket portion 54a has a smaller value compared to the thickness variation rate of PP (polypropylene) without fluoropolymer resin, thus providing a less meltable gasket 54 in the riveting structure of the electrode terminals.

[0118] Figure 13 This diagram illustrates the phenomenon of gasket melting in the riveting structure of the electrode terminals in the case of a conventional gasket according to a comparative example of the present invention. In the case of the conventional gasket of the embodiment of the present invention, melting occurs because it cannot withstand the high temperatures generated on the anode terminal side.

[0119] Figure 14This diagram illustrates the phenomenon that the gasket does not melt in the riveting structure of the electrode terminals in the case of a gasket comprising fluororesin according to an embodiment of the present invention. In the case of a gasket comprising fluororesin according to an embodiment of the present invention, the gasket does not melt between the hot electrode terminals and the battery canister, even when high temperatures are generated in the battery cell.

[0120] According to one embodiment of the present invention, the gasket 54 comprises a fluororesin, which is composed of an elastic polymer resin. For example, the fluororesin includes one or more selected from the group consisting of PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene).

[0121] According to one embodiment of the present invention, the compressive strength of the fluoropolymer is 10 MPa to 20 MPa. The compressive strength of the fluoropolymer is measured using the D695 ASTM test method. The compressive strength of the fluoropolymer refers to the maximum stress until failure when the fluoropolymer is subjected to a force compressing it in a single direction, for example, when subjected to a force to reduce the size of the fluoropolymer. It is expressed as the force per unit area (N / m²). 2 Or MP a) can be used to represent this. The above compressive strength, in contrast to tensile strength, is the capacity of the material to resist compression in order to withstand the load applied to reduce its size.

[0122] The compressive strength of the aforementioned fluororesin can be 10.5 MPa or higher, 11 MPa or higher, 11.5 MPa or higher, or 12 MPa or higher. The compressive strength of the aforementioned fluororesin can be 19.5 MPa or lower, 19 MPa or lower, 18.5 MPa or lower, or 18 MPa or lower. When the compressive strength of the aforementioned fluororesin meets the above ranges, the gasket containing the aforementioned fluororesin, compared to a gasket containing PP (polypropylene) but not fluororesin, can achieve good compression under higher temperature conditions and possesses elasticity. Therefore, even when subjected to greater compressive force during the manufacture of the riveting structure of the electrode terminals, it also possesses excellent sealing force, thereby preventing electrolyte and gas leakage.

[0123] According to one aspect, the electrode terminal 50 further includes a flat portion 50d, which is disposed at the end of the main body portion 50a exposed through the inner surface 52b of the bottom 52 of the battery can 51.

[0124] Preferably, the flat portion 50d and the inner surface 52b of the bottom 52 of the battery can 51 are parallel to each other. Here, 'parallel' means that they are substantially parallel when viewed with the naked eye.

[0125] According to one aspect, the angle θ between the inner flange 50c and the inner surface 52b of the bottom 52 of the battery can 51 is between 0° and less than 60°. The size of the angle is determined by the caulking strength when the electrode terminal 50 is disposed in the through hole 53 of the battery can 51 using a caulking method. In one example, the greater the caulking strength, the smaller the angle θ can be, down to 0°. When the angle exceeds 60°, the sealing effect of the gasket 54 decreases.

[0126] According to another aspect, a groove 55 is provided between the inner flange portion 50c and the flat portion 50d. The groove 55 has an asymmetrical groove cross-sectional structure. In one example, the asymmetrical groove is approximately V-shaped. The asymmetrical groove includes a sidewall 55a of the flat portion 50d and an inclined surface 55b of the inner flange portion 50c connected to the end of the sidewall 55a. The sidewall 55a is substantially perpendicular to the inner surface 52b of the bottom 52 of the battery can 51. 'Perpendicular' means substantially perpendicular when viewed with the naked eye. The groove 55 is formed by the shape of a caulking clamp when the electrode terminal 50 is disposed in the through hole 53 of the battery can 51 by a caulking method.

[0127] Preferably, the thickness of the inner flange portion 50c decreases as it moves away from the main body portion 50a of the electrode terminal 50.

[0128] According to one embodiment of the present invention, the gasket 54 includes: an outer gasket portion 54a sandwiched between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b sandwiched between the inner flange portion 50c and the inner surface of the bottom, wherein the inner gasket portion 54b and the outer gasket portion 54a may have different thicknesses depending on their positions.

[0129] According to another aspect, the outer gasket portion 54a and the inner gasket portion 54b may have different thicknesses depending on their positions. Preferably, in the region of the inner gasket portion 54b, the thickness of the area sandwiched between the inner edge 56 of the through hole 53 connected to the inner surface 52b of the bottom 52 of the battery can 51 and the inner flange portion 50c is relatively small. Preferably, there is a point of minimum thickness in the gasket region sandwiched between the inner edge 56 of the through hole 53 and the inner flange portion 50c. In addition, the inner edge 56 of the through hole 53 includes an opposing surface 57 opposite to the inner flange portion 50c.

[0130] On the other hand, the upper and lower ends of the inner wall of the through hole 53, which is perpendicular to the bottom 52 of the battery can 51, are chamfered to form a tapered surface toward the electrode terminal 50. However, the upper and / or lower ends of the inner wall of the through hole 53 are deformed into a gently curving surface. In this case, the pressure applied to the gasket 54 near the upper and / or lower ends of the inner wall of the through hole 53 can be further reduced.

[0131] According to one embodiment of the present invention, the gasket 54 includes: an outer gasket portion 54a sandwiched between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b sandwiched between the inner flange portion 50c and the inner surface of the bottom, wherein the inner gasket portion 54b extends longer than the inner flange portion 50c. Preferably, the inner gasket portion 54b forms an angle of 0° to 60° with the inner surface 52b of the bottom 52 of the battery can 51, and extends longer than the inner flange portion 50c.

[0132] In another aspect, taking the inner surface 52b of the bottom 52 of the battery can 51 as a reference, the height H1 of the flat portion 50d is higher than or equal to the end height H2 of the inner gasket portion 54b. Furthermore, taking the inner surface 52b of the bottom 52 of the battery can 51 as a reference, the height H1 of the flat portion 50d is higher than or equal to the end height H3 of the inner flange portion 50c.

[0133] When the height parameters H1, H2 and H3 meet the above conditions, it can prevent the internal flange 50c and the internal gasket 54b from interfering with other components.

[0134] In another aspect, taking the radius R2 of the bottom 52 of the battery can 51 as a reference, the radius R1 from the center of the main body 50a of the electrode terminal 50 to the edge of the outer flange 50b is 10% to 60%.

[0135] When R1 is small, there is insufficient space for welding electrical wiring components (busbars) when welding them to the electrode terminals 50. Conversely, when R1 is large, the welding space is reduced when welding electrical wiring components (busbars) to the outer surface 52a of the bottom 52 of the battery can 51, excluding the electrode terminals 50.

[0136] When the ratio R1 / R2 is adjusted to between 10% and 60%, sufficient welding space can be properly ensured for the outer surface of the electrode terminal 50 and the bottom 52 of the battery canister 51.

[0137] In addition, based on the radius R2 of the bottom 52 of the battery can 51, the radius R3 from the center of the main body 50a of the electrode terminal 50 to the edge of the flat part 50d is 4% to 30%.

[0138] When R3 decreases, a current collector is soldered to the flat portion 50d of electrode terminal 50 (refer to...). Figure 11 When the welding space is insufficient (79), the welding area of ​​the electrode terminal 50 decreases, thus increasing the contact resistance. In addition, R3 needs to be smaller than R1. When R3 increases, the thickness of the inner flange 50c becomes thinner, and the force of the inner flange 50c pressing the gasket 54 becomes smaller, which leads to a decrease in the sealing ability of the gasket 54.

[0139] When R3 / R2 is adjusted to between 4% and 30%, the flat portion 50d of the electrode terminal 50 and the current collector can be adequately ensured. Figure 11 The welding area of ​​79) makes the welding process easier and reduces the contact resistance of the welding area, preventing the sealing ability of the gasket 54 from decreasing.

[0140] According to an embodiment of the present invention, a riveting structure for the electrode terminal 50 can be formed using a caulking jig that moves up and down. First, a preform (not shown) of the electrode terminal 50 is inserted by clamping a gasket 54 into a through hole 53 formed in the bottom 52 of the battery can 51. The preform refers to the electrode terminal before riveting.

[0141] Next, the caulking fixture is inserted into the inner space of the battery can 51. The caulking fixture has grooves and protrusions on the surface opposite the preform to form the electrode terminal 50 in order to rivet the preform.

[0142] Next, the caulking fixture is moved downwards to pressurize the upper part of the preform and deform it into a riveted electrode terminal 50.

[0143] During the pressurization of the preform using the caulking clamp, the outer gasket 54a, sandwiched between the outer flange 50b and the outer surface 52a of the bottom 52 of the battery can 51, is elastically compressed, resulting in a reduction in its thickness. Additionally, the portion of the inner gasket 54b sandwiched between the inner edge 56 of the through hole 53 and the preform is elastically compressed by the inner flange 50c, thereby reducing its thickness even further than in other areas. Specifically, the area where the thickness of the inner gasket 54b is concentrated is... Figure 6 The portion shown by the dashed circle. This significantly improves the sealing and airtightness between the riveted electrode terminal 50 and the battery canister 51.

[0144] Preferably, the gasket 54 is compressed sufficiently in a manner that prevents physical damage during the riveting process of the preform and ensures the desired sealing strength.

[0145] In one example, when the gasket 54 is made of polyvinyl fluoride, the compression ratio of the gasket 54 at the position where it is compressed to its minimum thickness is preferably 60% or more. The compression ratio is the ratio of the thickness change before and after compression to the thickness before compression.

[0146] Preferably, the upper part of the preform is pressurized and formed in stages by moving the caulking fixture up and down at least twice. That is, the preform is pressurized and formed in stages and deformed multiple times. At this time, the pressure applied to the caulking fixture can be increased in stages. In this way, the stress applied to the preform is distributed multiple times, thereby preventing the gasket 54 from being damaged during the caulking process. In particular, the damage to the gasket is minimized when the portion of the internal gasket 54b sandwiched between the inner edge 56 of the through hole 53 and the preform is compressed by the internal flange portion 50c.

[0147] After the preform using the caulking fixture is pressurized and then separated from the battery can 51, such as... Figure 6 As shown, the riveting structure of the electrode terminal 50 in an embodiment of the present invention can be obtained.

[0148] According to the above embodiment, the caulking fixture pressurizes the upper part of the preform by moving up and down inside the battery can 51. Depending on the situation, a rotary fixture used in the conventional art can be used for pressurizing the preform.

[0149] However, the rotary jig rotates at a predetermined angle with the central axis of the battery can 51 as a reference. Therefore, the large radius of rotation of the rotary jig causes interference between it and the inner wall of the battery can 51. Furthermore, when the depth of the battery can 51 is large, the length of the rotary jig also increases accordingly. In this case, when the radius of rotation at the end of the rotary jig becomes large, the pressure forming of the preform cannot be achieved effectively. Therefore, pressure forming using a grooving jig is more efficient than using a rotary jig.

[0150] The riveting structure of the electrode terminal 50 in the above-described embodiment of the present invention can be applied to a battery cell.

[0151] In one example, the battery unit includes a battery canister 51. The battery canister is cylindrical. Its dimensions are: the diameter of the circular ends is 30mm to 55mm, and the height is 60mm to 120mm. Preferably, the diameter x height of the cylindrical battery canister is 46mm x 60mm, 46mm x 80mm, 46mm x 90mm, or 46mm x 120mm.

[0152] Preferably, the cylindrical battery cell is, for example, a cylindrical battery cell with a shape factor ratio (defined as the ratio of the diameter of the cylindrical battery cell to its height, i.e., the diameter Φ to the height H) that is approximately greater than 0.4.

[0153] Here, the shape factor refers to the value representing the diameter and height of the cylindrical battery cell. One embodiment of the cylindrical battery cell of this invention includes, for example, 46110 cells, 48750 cells, 48110 cells, 48800 cells, 46800 cells, and 46900 cells. In the shape factor value, the first two digits represent the diameter of the cell, the next two digits represent the height of the cell, and the final digit 0 indicates that the cross-section of the cell is circular.

[0154] One embodiment of the present invention is a cylindrical battery cell that is approximately cylindrical in shape, with a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor ratio of 0.418.

[0155] Another embodiment of the battery cell is a cylindrical battery cell that is generally cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 75 mm, and a shape factor ratio of 0.640.

[0156] Another embodiment of the battery cell is a cylindrical battery cell that is approximately cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 110 mm, and a shape factor ratio of 0.418.

[0157] Another embodiment of the battery cell is a cylindrical battery cell that is approximately cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 80 mm, and a shape factor ratio of 0.600.

[0158] Another embodiment of the battery cell is a cylindrical battery cell that is approximately cylindrical in shape, with a diameter of approximately 46 mm, a height of approximately 80 mm, and a shape factor ratio of 0.575.

[0159] Another embodiment of the battery cell is a cylindrical battery cell that is approximately cylindrical in shape, with a diameter of approximately 46 mm, a height of approximately 90 mm, and a shape factor ratio of 0.511.

[0160] Previously, battery cells with a form factor ratio of approximately 0.4 or less were used. For example, 18650 cells and 21700 cells were previously used. In the case of an 18650 cell, its diameter is approximately 18 mm, its height is approximately 65 mm, and its form factor ratio is 0.277. In the case of a 21700 cell, its diameter is approximately 21 mm, its height is approximately 70 mm, and its form factor ratio is 0.300.

[0161] According to one embodiment of the present invention, a battery cell is provided, comprising: an electrode assembly formed by winding a sheet-like first electrode plate and a second electrode plate with a separation membrane sandwiched between them, and including uncoated portions of the first electrode plate and the second electrode plate extending from both ends; a riveting structure for the electrode terminals of the above embodiment; and a sealing body, wherein the electrode assembly is housed inside a battery can, the first electrode plate is electrically connected to the battery can, the second electrode plate is electrically connected to the electrode terminals, and the sealing body can seal the open ends of the battery can to achieve insulation between the sealing body and the battery can.

[0162] According to one embodiment of the present invention, in the battery cell, the battery can includes a rolled edge portion pressed into the inside of the battery can in the region adjacent to the open end, the sealing body includes a non-polar cover plate and a sealing gasket sandwiched between the edge of the cover plate and the open end of the battery can, and the battery can includes a pressing portion that extends into the inside of the battery can and bends to surround the edge of the cover plate together with the sealing gasket and is fixed thereto.

[0163] Figure 7 This is a cross-sectional view of a battery cell 70 of an embodiment of the present invention cut along the length direction Y.

[0164] Reference Figure 7 The battery cell 70 of the embodiment includes an electrode assembly 71, which is formed by rolling a sheet-like first electrode plate and a second electrode plate together with a separation membrane sandwiched between them, and includes an uncoated portion 72 of the first electrode plate and an uncoated portion 73 of the second electrode plate extending from both ends.

[0165] In this embodiment, the first electrode plate is a cathode plate and the second electrode plate is an anode plate. Of course, the opposite can also be true.

[0166] Method and reference for winding electrode assembly 71 Figure 2 The method for winding the electrode assembly used in manufacturing tabless battery cells according to conventional technology is essentially the same.

[0167] When illustrating electrode assembly 71, only the uncoated portions 72 and 73 extending outwards from the separation membrane are shown in detail; the winding structure of the first electrode plate, the second electrode plate, and the separation membrane is omitted from the illustration.

[0168] Additionally, the battery unit 70 includes a battery canister 51 that houses the electrode assembly 71 and is electrically connected to the uncoated portion 72 of the first electrode plate.

[0169] Preferably, one side (lower part) of the battery can 51 is open. In addition, the bottom 52 of the battery can 51 has a structure in which the electrode terminals 50 are riveted to the through hole 53 by a caulking process.

[0170] Additionally, the battery cell 70 includes a gasket 54 disposed between the electrode terminal 50 and the outer diameter of the through hole 53.

[0171] Additionally, the battery cell 70 includes a sealing body 74 that seals the open end of the battery can 51 to achieve insulation between the sealing body and the battery can 51. Preferably, the sealing body 74 includes a non-polarized cover plate 74a and a sealing gasket 74b sandwiched between the edge of the cover plate 74a and the open end of the battery can 51.

[0172] The cover plate 74a is made of conductive metals such as aluminum, steel, and nickel. The sealing gasket 74b is made of insulating and elastic materials such as polypropylene, polybutylene terephthalate, and polyfluoroethylene. However, the present invention is not limited to the materials of the cover plate 74a and the sealing gasket 74b.

[0173] The cover plate 74a includes a vent notch 77 that ruptures when the internal pressure of the battery can 51 exceeds a threshold. The vent notch 77 is formed on both sides of the cover plate 74a. The vent notch 77 forms a continuous or discontinuous circular pattern, a linear pattern, or other patterns on the surface of the cover plate 74a.

[0174] The battery can 51 includes a crimping portion 75, which extends and bends inward toward the inside of the battery can 51 to secure the sealing body 74, and together with the sealing gasket 74b surrounds the edge of the cover plate 74a for fixation.

[0175] Additionally, the battery can 51 includes a rolled edge 76 pressed inwards in the region adjacent to the open end. When the sealing body 74 is fixed by the crimping part 75, the rolled edge 76 supports the edge of the sealing body 74, and in particular supports the outer peripheral surface of the sealing gasket 74b.

[0176] Additionally, the battery cell 70 also includes a first current collector 78 welded to the uncoated portion 72 of the first electrode plate. The first current collector 78 is made of a conductive metal such as aluminum, steel, or nickel. Preferably, at least a portion of the edge 78a of the first current collector 78 that does not contact the uncoated portion 72 of the first electrode plate is sandwiched between the rolled edge portion 76 and the sealing gasket 74b and fixed by a crimping portion 75. Alternatively, at least a portion of the edge 78a of the first current collector 78 is fixed to the inner peripheral surface 76a of the rolled edge portion 76 adjacent to the crimping portion 75 by welding.

[0177] Additionally, the battery cell 70 includes a second current collector 79 welded to the uncoated portion 73 of the second electrode plate. Preferably, at least a portion of the second current collector 79, such as the central portion 79a, is welded to the flat portion 50d of the electrode terminal 50.

[0178] Preferably, when welding the second current collector 79, the welding tool is inserted through the core 80 present in the core of the electrode assembly 71 to reach the welding area of ​​the second current collector 79. Furthermore, when welding the second current collector 79 to the flat portion 50d of the electrode terminal 50, the electrode terminal 50 supports the welding area of ​​the second current collector 79, thus applying stronger pressure to the welding area and improving welding quality. Additionally, the flat portion 50d of the electrode terminal 50 has a wide area, thus ensuring a wider welding area. This reduces the contact resistance of the welding area, thereby reducing the internal resistance of the battery cell 70. The face-to-face welding structure of the riveted electrode terminal 50 and the second current collector 79 is very useful for rapid charging using a high charge rate (c-rate) current. Because the current density per unit area can be reduced in the cross-section in the direction of current flow, the heat generated in the current path can be reduced compared to the past.

[0179] When welding the flat portion 50d of the electrode terminal 50 to the second current collector 79, any one of the following methods can be used: laser welding, ultrasonic welding, spot welding, and resistance welding. The area of ​​the flat portion 50d can be adjusted to different values ​​depending on the welding method, but for the sake of welding strength and ease of welding process, it is preferable to adjust the area of ​​the flat portion 50d to 2 mm or more.

[0180] In one example, when the flat portion 50d and the second collector plate 79 are welded by laser in a circular pattern with continuous or discontinuous line welding, it is preferable to form the diameter of the flat portion 50d to be 4 mm or more. Meeting this condition ensures weld strength and facilitates the insertion of the laser welding tool into the core 80 of the electrode assembly 71 for the welding process.

[0181] In another example, when the flat portion 50d and the second current collector 79 are welded together in a circular pattern using ultrasound, the diameter of the flat portion 50d is preferably 2 mm or more. When the diameter of the flat portion 50d meets this condition, the weld strength is ensured, facilitating the insertion of an ultrasonic welding tool into the core 80 of the electrode assembly 71 for the welding process.

[0182] Additionally, the battery cell 70 also includes an insulating cover 80'. The insulating cover 80' is sandwiched between the second current collector 79 and the inner surface 52b of the bottom 52 of the battery can 51, and between the inner peripheral surface 51a of the side wall of the battery can 51 and the electrode assembly 71. Preferably, the insulating cover 80' includes a welding hole 80a that exposes the flat portion 50d of the electrode terminal 50 to the side of the second current collector 79, and covers the surface of the second current collector 79 and one side (upper) edge of the electrode assembly 71.

[0183] Preferably, the uncoated portions 72 and 73 of the first electrode plate and / or the second electrode plate are bent from the outer periphery of the electrode assembly 71 toward the core, forming bending surfaces at the upper and lower parts of the electrode assembly 71. Additionally, the first current collector 78 is welded to the bending surface formed by bending the uncoated portion 72 of the first electrode plate, and the second current collector 79 is welded to the bending surface formed by bending the uncoated portion 73 of the second electrode plate.

[0184] To alleviate the stress generated when the uncoated portions 72 and 73 are bent, the first electrode plate and / or the second electrode plate have the same characteristics as conventional electrode plates (see reference). Figure 1 Different improved structures.

[0185] Figure 8 This is a top view illustrating the structure of an electrode plate 90 according to a preferred embodiment of the present invention.

[0186] Reference Figure 8 The electrode plate 90 includes a sheet-shaped current collector 91 made of a conductive foil, an active material layer 92 formed on at least one side of the current collector 91, and an uncoated portion 93 at the long side end of the current collector 91 where no active material is coated.

[0187] Preferably, the uncoated portion 93 includes multiple slotted slices 93a. The multiple slices 93a form multiple groups, and the slices 93a belonging to each group have the same height (length in the Y direction) and / or width (length in the X direction) and / or spacing. The number of slices 93a belonging to each group may be increased or decreased compared to the number shown in the figure. The slices 93a can be trapezoidal, or can be modified into quadrilaterals, parallelograms, semicircles, or semi-ellipses.

[0188] Preferably, the height of the slice 93a increases in stages as it moves from the core side toward the outer periphery. Additionally, the uncoated portion 93' on the core side adjacent to the core side may not include the slice 93a, and the height of the uncoated portion 93' on the core side may be smaller than that of other uncoated portion areas.

[0189] Optionally, the electrode plate 90 includes an insulating coating 94 that covers the boundary between the active material layer 92 and the uncoated portion 93. The insulating coating 94 comprises an insulating polymer resin and optionally also includes an inorganic filler. The insulating coating 94 prevents the ends of the active material layer 92 from contacting active material layers of opposite polarity that are opposed by the separation membrane, structurally supporting the bending of the slitting slice 93a. Therefore, when the electrode plate 90 is wound into an electrode assembly, it is preferable that at least a portion of the insulating coating 94 is exposed to the outside from the separation membrane.

[0190] Figure 9 This is a cross-sectional view of the electrode assembly 100, which is formed by cutting the uncoated portion of the electrode plate 90 of the embodiment of the present invention along the length direction Y and applying it to the first electrode plate and the second electrode plate.

[0191] Reference Figure 9 The electrode assembly 100 can be referenced Figure 2 The membrane is manufactured using the winding method described herein. For ease of explanation, the protruding structures of the uncoated portions 72 and 73 extending beyond the separation membrane are shown in detail, while the winding structures of the first electrode plate, the second electrode plate, and the separation membrane are omitted from the illustration. The downward-protruding uncoated portion 72 extends from the first electrode plate, and the upward-protruding uncoated portion 73 extends from the second electrode plate.

[0192] A schematic illustration shows the pattern of varying heights of the uncoated portions 72 and 73. That is, the heights of the uncoated portions 72 and 73 vary irregularly depending on the position of the cut section. For example, when the side portion of the trapezoidal slice 93a is cut, the height of the uncoated portion on the cross-section is lower than the height of the slice 93a. Therefore, it should be understood that the heights of the uncoated portions 72 and 73 illustrated in the figure representing the cross-section of the electrode assembly 100 correspond to the average height of the uncoated portions included in each winding coil.

[0193] like Figure 10 As shown, the uncoated portions 72 and 73 bend from the outer periphery of the electrode assembly 100 toward the core side. Figure 9 In the diagram, the bent portion 101 is indicated by a dashed box. When bending the uncoated portions 72 and 73, adjacent slices in the radial direction overlap to form multiple layers, creating bending surfaces 102 on the upper and lower parts of the electrode assembly 100. At this time, the uncoated portion on the core side ( Figure 8The core 80 (93') has a low height and does not bend. The height h of the innermost bent slit is less than or equal to the radial length r of the winding area formed by the uncoated portion 93' of the core without slit structure. Therefore, the core 80 located in the core of the electrode assembly 100 is not closed by the bent slit. When the core 80 is not closed, the electrolyte injection process is easier, improving the electrolyte injection efficiency. In addition, the electrode terminals 50 and the second collector board 79 can be easily welded by inserting a welding tool through the core 80.

[0194] In an embodiment of the present invention, the cover plate 74a of the sealing body 74 in the battery cell 70 is non-polarized. Instead, the first current collector 78 is connected to the side wall of the battery can 51, so that the outer surface 52a of the bottom 52 of the battery can 51 has a polarity opposite to that of the electrode terminals 50. Therefore, when multiple cells are connected in series and / or in parallel, wiring such as busbar connection is performed at the upper part of the battery cell 70 using the outer surface 52a of the bottom 52 of the battery can 51 and the electrode terminals 50. This increases the number of cells mounted in the same space and improves the energy density.

[0195] In this invention, any active material known in the art can be used for the anodic active material coated onto the anode plate and the cathode active material coated onto the cathode plate.

[0196] As an example, anolyte active materials include those with the general chemical formula A[A] x M y ]O 2+z (A includes at least one element selected from Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x ≥ 0, 1 ≤ x + y ≤ 2, -0.1 ≤ z ≤ 2; the stoichiometric coefficients of the components included in x, y, z, and M are selected in a manner that maintains the electroneutrality of the compound) represent an alkali metal compound.

[0197] In another example, the anolyte is an alkali metal compound xLiM disclosed in US6,677,082, US6,680,143, etc. 1 O2-(1-x)Li2M 2 O3(M 1 Includes at least one element having an average oxidation state of 3; M 2 Includes at least one element having an average oxidation state of 4; 0 ≤ x ≤ 1).

[0198] In yet another example, the anolyte is a substance with the general chemical formula Li. a M 1x Fe 1-x M 2 P y1-y M 3 z O 4-z (M 1 includes at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 includes at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 includes halogen elements selectively including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; including the stoichiometric coefficients of the components in a, x, y, z, M 1 、M 2 、and M 3 are selected in a manner that maintains the electrical neutrality of the compound), or lithium metal phosphate represented by Li3M2(PO4)3 [M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0199] Preferably, the anode active material includes primary particles and / or secondary particles aggregated from primary particles.

[0200] In one example, for the cathode active material, carbon materials, lithium metal or lithium metal compounds, silicon or silicon compounds, tin or tin compounds, etc. can be used. Metal oxides such as TiO2 and SnO2 with a potential less than 2V can also be used as the electrode active material. As the carbon material, low-crystalline carbon, high-crystalline carbon, etc. can be used.

[0201] As the separation membrane, a porous polymer film such as a porous polymer film made of polyolefin polymers such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. can be used alone or laminated. As another example, as the separation membrane, a usual porous non-woven fabric, such as a non-woven fabric composed of high-melting-point glass fibers, polyethylene terephthalate fibers, etc., can be used.

[0202] A coating of inorganic particles is included on at least one surface of the separation membrane. And the separation membrane itself can also be used as a coating of inorganic particles. The particles constituting the coating can have a structure combined with an adhesive so that there is an interstitial volume between adjacent particles.

[0203] Inorganic particles can be composed of inorganic materials with a dielectric constant of 5 or higher. As a non-limiting example, the aforementioned inorganic particles may include those selected from Pb(Zr,Ti)O3 (PZT), Pb... 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb) 2 / 3 It refers to at least one substance in the group consisting of O3-PbTiO3 (PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0204] Electrolytes can be those with A + B - Salts with similar structures. Among them, A... + Including Li + Na + K + Ions consisting of basic metal cations or combinations thereof. Additionally, B... - Including the choice 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 - Any one or more anions in the group.

[0205] Electrolytes can also be used in organic solvents. Suitable organic solvents 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 mixtures thereof.

[0206] The cylindrical battery cells described in the above embodiments can be used to manufacture battery packs.

[0207] Figure 11 This is a diagram that schematically illustrates the structure of a battery pack according to an embodiment of the present invention.

[0208] Reference Figure 11 The battery pack 200 of this embodiment includes an assembly that electrically connects cylindrical battery cells 201 and a housing 202 that houses them. The cylindrical battery cell 201 is the battery cell of the above embodiment. In the accompanying drawings, for ease of illustration, components such as busbars, cooling units, and external terminals used for electrically connecting the cylindrical battery cells 201 are omitted from the drawings.

[0209] The battery pack 200 is installed in the vehicle. The vehicle, for example, can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle can be a four-wheeled vehicle or a two-wheeled vehicle.

[0210] Figure 12 It is used for including Figure 11 The diagram illustrates the battery pack of a 200 car.

[0211] Reference Figure 12 An embodiment of the present invention, a vehicle V, includes a battery pack 200 according to an embodiment of the present invention. The vehicle V receives power from the battery pack 200 according to an embodiment of the present invention to operate.

[0212] Example

[0213] Example 1.

[0214] (1) Manufacturing the riveting structure of the electrode terminals

[0215] One side of the battery can (diameter: 45mm to 47mm, material: steel) is open, and electrode terminals are riveted by a caulking process through a through hole formed in the bottom of the battery can.

[0216] In the riveting structure of the electrode terminal including the aforementioned riveted electrode terminal, the electrode terminal includes a main body portion inserted into the through hole, an outer flange portion exposed through the outer surface of the bottom, and an inner flange portion exposed through the inner surface of the bottom. A gasket containing PFA (Perfluoroalkoxy) is provided between the electrode terminal and the outer diameter of the through hole, thereby creating the riveting structure of the electrode terminal. The outer diameter of the gasket is 16 mm, and the thickness of the outer gasket portion sandwiched between the outer flange portion and the outer surface of the bottom is 0.5 mm.

[0217] (2) Manufacturing battery cells

[0218] An electrode assembly is manufactured by sequentially stacking and winding a sheet-like cathode, a polyethylene separation membrane, and an anode. The wound electrode assembly is then inserted into a battery can containing a riveted structure with electrode terminals, followed by the injection of electrolyte. Finally, a cylindrical battery can is sealed using a sealing body to manufacture a battery cell.

[0219] At this time, in the battery cell, the cathode plate of the electrode assembly and the battery can are electrically connected, and the anode plate and the electrode terminals are electrically connected, so that the seal body and the battery can are insulated.

[0220] Comparative Example 1.

[0221] Except for the case where a gasket containing PP (Polypropylene) is provided between the electrode terminal and the outer diameter of the through hole in the riveting structure of the electrode terminal, the electrode terminal including the riveting structure and the battery cell including it were manufactured by the same method as in Example 1.

[0222] Experimental Example

[0223] Experimental Example 1. Measuring the thickness change rate of the external gasket.

[0224] Regarding the thickness change rate of the external gasket, the thickness X1 of the external gasket at room temperature (23°C) was measured, and the thickness X2 of the external gasket was measured again after being placed at 100°C for 10 minutes. The result was calculated based on the difference between the thickness X1 of the external gasket at room temperature and the thickness X2 of the external gasket at a temperature higher than room temperature.

[0225] The formula for calculating the thickness change rate of the external gasket is as follows.

[0226] Thickness variation rate (%) of the external gasket portion = [(X1-X2) / X1]×100

[0227] In the formula for calculating the thickness change rate of the external gasket, the thickness X2 of the external gasket was measured after being placed at 150°C for 10 minutes and after being placed at 230°C for 30 minutes, thereby calculating the thickness change rate of the external gasket.

[0228] The thickness X1 of the outer gasket at room temperature and the thickness X2 of the outer gasket at temperatures above room temperature were measured and recorded in Table 2 under various temperature and time conditions.

[0229] The thicknesses X1 and X2 of the aforementioned outer gasket portion were measured using a 3D shape measuring instrument (Keyence shape measuring instrument, model: Keyence VR5000, Korea). The thicknesses X1 and X2 of the outer gasket portion were the average of the thinnest portions (54 aT) in three measurements taken using the 3D shape measuring instrument from images of a cross-section of the battery cell including the outer gasket portion cut along the length Y direction. The battery cell was cut using a molding apparatus, a polishing apparatus (model: Tegramin-30) of a grinding unit, and a grinding machine that cuts the end diameter of the battery cell along the length Y direction of the battery cell.

[0230] [Table 2]

[0231]

[0232] The thickness change rate of the outer gasket was calculated based on the thickness X1 of the outer gasket at room temperature and the thickness X2 of the outer gasket at temperatures above room temperature, and is recorded in Table 3.

[0233] [Table 3]

[0234]

[0235] Referring to Tables 2 and 3 above, the thickness variation rate of the outer gasket portion including fluororesin is within the range of 10% or less. Therefore, compared with the thickness variation rate of the outer gasket portion including PP (Polypropylene), the thickness variation rate of the outer gasket portion including PFA (Perfluoroalkoxy) has a smaller value. This provides a less meltable gasket in the riveting structure of the electrode terminal, thus preventing short circuits caused by the gasket melting between the electrode terminal and the battery canister.

[0236] The present invention has been described above with reference to limited embodiments and accompanying drawings, but the present invention is not limited thereto. Those skilled in the art can make various modifications and variations within the equivalent scope of the technical concept of the present invention and the claims set forth below.

Claims

1. A riveting structure for electrode terminals, comprising: The battery container has one side open. Electrode terminals are riveted through through holes formed in the bottom of the aforementioned battery can; and A gasket is disposed between the electrode terminal and the outer diameter of the through hole. The aforementioned electrode terminals include: The main body is inserted into the aforementioned through hole; An outer flange portion extends around the outer surface of the main body portion, which is exposed through the outer surface of the bottom; and An inner flange extends from the other side of the main body portion, which is exposed through the inner surface of the bottom, toward the inner surface. The aforementioned gasket comprises fluororesin and includes: an outer gasket portion sandwiched between the outer flange portion and the outer surface of the bottom; and an inner gasket portion sandwiched between the inner flange portion and the inner surface of the bottom. The thickness variation rate of the aforementioned external gasket portion satisfies the following equation 1: [Formula 1] 0%≤[(X1-X2) / X1]×100(%)≤10% In Formula 1 above, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion after being placed at 100°C for 10 minutes. The angle between the aforementioned internal gasket portion and the aforementioned inner surface of the bottom is 60° or less. The electrode terminal further includes a flat portion, which is disposed at the end of the main body portion exposed through the inner surface of the bottom. Based on the inner surface of the bottom, the height of the flat portion is higher than the height of the end of the inner flange portion.

2. The riveting structure for the electrode terminals according to claim 1, wherein, The thickness variation rate of the aforementioned external gasket portion satisfies the following equation 2: [Equation 2] 0%≤[(X1-X2) / X1]×100(%)≤10% In Formula 2 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 150°C for 10 minutes.

3. The riveting structure for the electrode terminals according to claim 1, wherein, The thickness variation rate of the aforementioned external gasket portion satisfies the following equation 3: [Formula 3] 0%≤[(X1-X2) / X1]×100(%)≤10% In Formula 3 above, X1 is the thickness of the outer gasket at room temperature, and X2 is the thickness of the outer gasket after being placed at 230°C for 30 minutes.

4. The riveting structure for the electrode terminals according to claim 1, wherein, The melting point of the above-mentioned fluoropolymer is above 280°C.

5. The riveting structure for the electrode terminals according to claim 1, wherein, The aforementioned fluororesins include one or more selected from the group consisting of PFA (Perfluoroalkoxy) and PTFE (Polytetrafluoroethylene).

6. The riveting structure for the electrode terminals according to claim 1, wherein, The aforementioned flat portion and the aforementioned bottom inner surfaces are parallel to each other.

7. The riveting structure for the electrode terminals according to claim 1, wherein, The angle between the aforementioned inner flange and the aforementioned inner surface of the bottom is 0° to 60°.

8. The riveting structure for the electrode terminals according to claim 1, wherein, A groove is provided between the aforementioned inner flange portion and the aforementioned flat portion.

9. The riveting structure for the electrode terminals according to claim 8, wherein, The aforementioned groove has an asymmetrical groove cross-sectional structure.

10. The riveting structure for the electrode terminals according to claim 9, wherein, The aforementioned asymmetric groove includes the sidewall of the aforementioned flat portion and the inclined surface of the aforementioned internal flange portion connected to the end of the aforementioned sidewall.

11. The riveting structure for the electrode terminals according to claim 10, wherein, The aforementioned sidewall is perpendicular to the aforementioned inner surface of the bottom.

12. The riveting structure for the electrode terminals according to claim 1, wherein, The thickness of the aforementioned internal flange decreases as it moves away from the aforementioned main body.

13. The riveting structure for the electrode terminals according to claim 1, wherein, The thickness of the aforementioned internal gasket and the aforementioned external gasket varies depending on their location. In the region of the aforementioned internal gasket portion, the thickness of the area between the inner edge of the through hole connected to the inner surface of the bottom and the aforementioned internal flange portion is relatively smaller than that of other areas, and The thickness of the outer gasket portion sandwiched between the outer flange portion and the outer surface of the bottom of the battery can is reduced.

14. The riveting structure for the electrode terminals according to claim 13, wherein, The inner edge of the aforementioned through hole includes a facing surface that is opposite to the aforementioned inner flange.

15. The riveting structure for the electrode terminals according to claim 1, wherein, The aforementioned internal gasket portion extends to be longer than the aforementioned internal flange portion.

16. The riveting structure for the electrode terminals according to claim 1, wherein, Based on the inner surface of the bottom, the height of the flat portion is higher than or equal to the height of the end of the inner gasket portion.

17. The riveting structure for the electrode terminals according to claim 1, wherein, Based on the radius of the bottom, the radius from the center of the main body to the edge of the outer flange is 10% to 60%.

18. The riveting structure for the electrode terminals according to claim 1, wherein, Based on the radius of the bottom, the radius from the center of the main body to the edge of the flat part is 4% to 30%.

19. A battery cell comprising: An electrode assembly, formed by winding sheet-like first and second electrode plates with a separation membrane sandwiched between them, and including uncoated portions of the first and second electrode plates extending from both ends; a riveting structure for the electrode terminals according to any one of claims 1 to 18; and a sealing body. The aforementioned electrode assembly is housed inside the battery canister. The first electrode plate is electrically connected to the battery canister, and the second electrode plate is electrically connected to the electrode terminals. The aforementioned sealing body seals the open end of the aforementioned battery canister, thereby achieving insulation between the sealing body and the battery canister.

20. The battery cell according to claim 19, wherein, The aforementioned battery can includes a rolled edge that is pressed inwards towards the inside of the battery can in the region adjacent to the open end. The aforementioned sealing body includes a non-polar cover plate and a sealing gasket sandwiched between the edge of the cover plate and the open end of the battery can. The battery can includes a crimping part that extends and bends inward toward the inside of the battery can to surround the edge of the cover plate together with the sealing gasket for fixation.

21. The battery cell according to claim 20, wherein, The aforementioned cover includes a vent that ruptures when the pressure inside the battery can exceeds a threshold.

22. The battery cell of claim 20, further comprising: The first current collector is soldered to the uncoated portion of the first electrode plate. In the first current collector, at least a portion of the edge that does not contact the uncoated portion of the first electrode plate is sandwiched between the rolled edge and the sealing gasket and is fixed by the crimping portion.

23. The battery cell according to claim 22, wherein, At least a portion of the edge of the first current collector is fixed to the inner circumferential surface of the rolled edge portion adjacent to the crimp portion by welding.

24. The battery cell of claim 19, further comprising: The second current collector is soldered to the uncoated portion of the aforementioned second electrode plate. At least a portion of the second current collector is welded to the flat portion of the electrode terminal.

25. The battery cell of claim 24, further comprising: An insulating cover is sandwiched between the second current collector and the inner circumferential surface of the bottom of the battery can, and between the inner circumferential surface of the side wall of the battery can and the electrode assembly. The insulating cover includes a welding hole that exposes the flat portion of the electrode terminal to the side of the second current collector, and covers the surface of the second current collector and one edge of the electrode assembly.

26. A battery pack comprising at least one battery cell according to any one of claims 19 to 25.

27. An automobile comprising at least one battery pack as claimed in claim 26.

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