Rivet structure for electrode terminal, battery cell including the same, battery pack, and automobile

Abstract

The present invention provides a riveting structure for an electrode terminal, and a cylindrical battery cell, a battery pack, and an automobile including the same. The riveting structure for an electrode terminal includes a battery can having one side open; 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 the filing date of Korean Patent Application No. 10-2021-0165315, filed with the Korean Intellectual Property Office on November 26, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a rivet structure for an electrode terminal, and to a battery cell, a battery pack, and an automobile that include the same. [Background technology]

[0003] Secondary batteries, which are highly adaptable to a variety of products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by electrical sources.

[0004] Such secondary batteries have not only the primary advantage of dramatically reducing the use of fossil fuels, but also the advantage of not producing any by-products from the use of energy, and are therefore attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

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

[0006] Meanwhile, cylindrical, prismatic, and pouch-shaped battery cells are known as types of secondary battery cells. The battery cell may be cylindrical. The battery cell is formed by winding a jelly-roll-shaped electrode assembly, with an insulating separator interposed between an anode and a cathode, and inserting the jelly-roll-shaped electrode assembly into a battery can together with an electrolyte to form a battery. Strip-shaped electrode tabs may be connected to the uncoated portions of the anode and cathode, respectively, and the electrode tabs electrically connect the electrode assembly to electrode terminals exposed to the outside. The anode electrode terminal is a sealed cap plate that seals the opening of the battery can, and the cathode electrode terminal is the battery can.

[0007] However, conventional battery cells with this structure have problems such as high resistance, large heat generation, and poor current collection efficiency because current concentrates on the strip-shaped electrode tabs connected to the anode uncoated portion and / or cathode uncoated portion.

[0008] Resistance and heat generation are not major issues for small cylindrical battery cells with form factors of 18650 or 21700. However, when the form factor of cylindrical battery cells is increased to apply them to electric vehicles, a lot of heat is generated around the electrode tabs during the fast charging process, which can cause the cylindrical battery cell to catch fire.

[0009] To solve this problem, a battery cell (so-called tab-less battery cell) has been proposed, which has a structure in which an anode uncoated area and a cathode uncoated area are located at the top and bottom of a jelly roll-type electrode assembly, respectively, and a current collecting plate is welded to these uncoated areas to improve current collection efficiency.

[0010] Figures 1 to 3 are diagrams showing the manufacturing process of a tabless battery cell. Figure 1 shows the structure of the electrode plate, Figure 2 shows the process of winding the electrode plate, and Figure 3 shows the process of welding a current collecting plate to the folded surface of the uncoated portion. Figure 4 is a cross-sectional view of the tabless battery cell cut in the longitudinal direction Y.

[0011] 1 to 4, the positive electrode plate 10 and the negative electrode plate 11 have a structure in which an active material 21 is coated on a sheet-shaped current collector 20, and include a non-coating portion 22 on one long side along the winding direction X.

[0012] The electrode assembly A is fabricated by sequentially stacking an anode plate 10 and a cathode plate 11 together with two separators 12, as shown in Figure 2, and then winding the stack 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 positive electrode plate 10 and the uncoated portion 11a of the negative electrode plate 11 are bent toward the core, and then the current collecting plates 30 and 31 are welded to the uncoated portions 10a and 11a, respectively.

[0014] Since separate electrode tabs are not attached to the positive electrode uncoated region 10a and the negative electrode uncoated region 11a, and current collecting plates 30 and 31 are connected to external electrode terminals, a current path with a large cross-sectional area is formed along the winding axis direction of electrode assembly A (see arrow), which has the advantage of reducing the resistance of the battery cell, as resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows.

[0015] However, as the form factor of cylindrical battery cells increases and the magnitude of the charging current during fast charging increases, the heat generation problem reoccurs even in table-less battery cells.

[0016] Specifically, as shown in Figure 4, a conventional table-less battery cell 40 includes a battery can 41 and a sealing body 42. The sealing body 42 includes a cap plate 42a, a sealing gasket 42b, and a connecting plate 42c. The sealing gasket 42b encloses the edge of the cap plate 42a and is fixed by a crimping portion 43. In addition, the electrode assembly A is fixed in the battery can 41 by a beading portion 44 to prevent vertical movement.

[0017] Typically, the positive electrode terminal is the cap plate 42a of the sealed body 42, and the negative electrode terminal is the battery can 41. Therefore, the current collecting plate 30 coupled to the uncoated portion 10a of the positive electrode plate 10 is electrically connected to the connecting plate 42c attached to the cap plate 42a via a strip-shaped lead 45. Also, the current collecting plate 31 coupled to the uncoated portion 11a of the negative electrode plate 11 is electrically connected to the bottom of the battery can 41. An insulator 46 covers the current collecting plate 30 to prevent the battery can 41 and the uncoated portion 10a of the positive electrode plate 10, which have opposite polarities, from coming into contact with each other and causing a short circuit.

[0018] When the current collecting plate 30 is connected to the connecting plate 42c, a strip-shaped lead 45 is used. The lead 45 is either separately attached to the current collecting plate 30 or is integrally formed with the current collecting plate 30. However, since the lead 45 is a thin strip, its cross-sectional area is small and a large amount of heat is generated when a fast charging current flows through it. In addition, the excess heat generated in the lead 45 is transferred to the electrode assembly A and causes the separator 12 to contract, which can lead to an internal short circuit, a major cause of thermal runaway.

[0019] The leads 45 also occupy a considerable amount of installation space within the battery can 41. Therefore, the battery cell 40 including the leads 45 has low space efficiency and is limited in its ability to increase energy density.

[0020] Furthermore, in order to connect conventional table-less battery cells 40 in series and / or parallel, busbar components must be connected to the cap plate 42a of the sealed body 42 and the bottom surface of the battery can 41, resulting in reduced space efficiency. A battery pack installed in an electric vehicle includes hundreds of battery cells 40. Therefore, the inefficiency of electrical wiring causes considerable trouble during the electric vehicle assembly process and battery pack maintenance. Summary of the Invention [Problem to be solved by the invention]

[0021] The present invention has been made in light of the background of the prior art described above, and aims to improve the electrode terminal structure of a battery cell to increase the space efficiency within a battery can, thereby reducing the internal resistance of the battery cell and increasing the energy density.

[0022] Another technical object of the present invention is to improve the electrode terminal structure of a battery cell to increase the cross-sectional area of ​​a current path, thereby alleviating the problem of internal heat generation that occurs during fast charging.

[0023] Another technical object of the present invention is to provide a battery cell with an improved structure in which electrical wiring for series and / or parallel connection of battery cells can be performed on one side of the battery cell.

[0024] It is still another technical object of the present invention to provide a battery pack manufactured using battery cells having an improved structure, and a vehicle including the battery pack.

[0025] However, the technical problems that the present invention aims to solve are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0026] According to one embodiment of the present invention, there is provided a battery battery comprising: a battery can having one open side; an electrode terminal riveted through a through-hole formed at the bottom of the battery can; and a gasket disposed between the electrode terminal and an outer diameter of the through-hole, the electrode terminal includes a body portion inserted into the through-hole, an outer flange portion extending from around one side of the body portion exposed through the outer surface of the bottom portion along the outer surface, and an inner flange portion extending from around the other side of the body portion exposed through the inner surface of the bottom portion toward the inner surface, The gasket contains a fluororesin and provides a rivet structure for the electrode terminal.

[0027] According to one embodiment of the present invention, there is provided a battery battery comprising: a battery can having one open side; an electrode terminal riveted through a through-hole formed at the bottom of the battery can; and a gasket disposed between the electrode terminal and an outer diameter of the through-hole, the electrode terminal includes a body portion inserted into the through-hole; an outer flange portion extending from around one side of the body portion exposed through the outer surface of the bottom portion along the outer surface; and an inner flange portion extending from around the other side of the body portion exposed through the inner surface of the bottom portion toward the inner surface, the gasket includes an outer gasket portion interposed between the outer flange portion and the outer surface of the bottom; and an inner gasket portion interposed between the inner flange portion and the inner surface of the bottom, The rivet structure for an electrode terminal is provided, wherein the change rate of the thickness of the outer gasket portion satisfies the following formula 1: [Formula 1] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 1, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 100° C. for 10 minutes.

[0028] Another embodiment of the present invention is a battery cell including: an electrode assembly in which sheet-shaped first and second electrode plates are wound with a separator interposed therebetween, the electrode assembly including uncoated portions of the first and second electrode plates extending from both side edges and exposed; a rivet structure for an electrode terminal according to an embodiment of the present invention; and a sealed body, the electrode assembly is contained within the battery can, the first electrode plate and the battery can are electrically connected, and the second electrode plate and the electrode terminal are electrically connected; The sealing body seals the open end of the battery can so as to be insulated from the battery can, providing a battery cell.

[0029] Yet another embodiment of the present invention provides a battery pack and a vehicle including at least one of the above-described battery cells. [Effects of the Invention]

[0030] According to one aspect of the present invention, the electrode terminal structure of the battery cell is improved to increase the space efficiency within the battery can, thereby reducing the internal resistance of the battery cell and increasing the energy density.

[0031] The sealing gasket of a conventional tablet-less battery cell is installed between the cap plate (positive terminal) and the battery can (negative terminal) to prevent short circuits. When using PP (Polypropylene) or PBT (Polybutylene Terephthalate), which are conventional sealing gasket materials, they have a low melting point and can melt and cause short circuits when the energy density of the battery cell increases.

[0032] According to another aspect of the present invention, a gasket including a fluororesin is provided to realize the above-described electrode terminal structure of a battery cell, thereby preventing a short circuit caused by melting of the gasket between the electrode terminal and the battery can when high heat is generated during an external short circuit evaluation or when the energy density of the battery cell increases.

[0033] According to another aspect of the present invention, the problem of internal heat generation occurring during fast charging can be alleviated by improving the electrode terminal structure of the battery cell to increase the cross-sectional area of ​​the current path.

[0034] According to another aspect of the present invention, electrical wiring for connecting battery cells in series and / or in parallel can be performed on one side of the battery cells.

[0035] According to still another aspect of the present invention, it is possible to provide a battery pack manufactured using a battery cell having an improved structure, and a vehicle including the battery pack.

[0036] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited to the matters depicted in such drawings. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a plan view showing the structure of an electrode plate used in a conventional tabless battery cell. [Figure 2] 1A to 1C are diagrams illustrating a winding process of an electrode assembly included in a conventional tabless battery cell. [Figure 3] 3A and 3B are diagrams showing a process in which a current collecting plate is welded to the folded surface of the non-coating portion in the electrode assembly of FIG. 2. [Figure 4] 1 is a cross-sectional view of a conventional tablets battery cell cut in the longitudinal direction Y. FIG. [Figure 5] 1 is a cross-sectional view showing a rivet structure of an electrode terminal according to an embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged cross-sectional view of a portion indicated by a dotted circle in FIG. 5. [Figure 7] 2 is a cross-sectional view of a battery cell according to an embodiment of the present invention taken along a longitudinal direction Y. FIG. [Figure 8] 1 is a plan view illustrating an example of the structure of an electrode plate according to a preferred embodiment of the present invention; [Figure 9] 1 is a cross-sectional view taken along the longitudinal direction Y of an electrode assembly in which a segmented structure of the uncoated portion of an electrode plate according to an embodiment of the present invention is applied to a first electrode plate and a second electrode plate. [Figure 10] 3 is a cross-sectional view of an electrode assembly in which an uncoated portion is bent in accordance with an embodiment of the present invention, taken along a longitudinal direction Y. FIG. [Figure 11] 1 is a diagram showing a schematic configuration of a battery pack including a battery cell according to an embodiment of the present invention; [Figure 12] 1 is a diagram showing a schematic configuration of a vehicle including a battery pack according to an embodiment of the present invention; [Figure 13]10 is a photograph showing a phenomenon in which the gasket melts due to the rivet structure of the electrode terminal in the case of the gasket according to the comparative example of the present invention. [Figure 14] 10 is a photograph showing a phenomenon in which a gasket containing a fluororesin according to an embodiment of the present invention does not melt due to a rivet structure of an electrode terminal. [Figure 15] 4 is a photograph showing a cross section of a rivet structure of an electrode terminal according to an embodiment of the present invention, cut along the longitudinal direction Y of a battery cell. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be interpreted as being limited to their commonly used or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to best describe his or her invention.

[0039] 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 the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can replace them at the time of this application.

[0040] In order to facilitate understanding of the present invention, the accompanying drawings may not be drawn to actual size, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0041] According to one embodiment of the present invention, there is provided a battery battery comprising: a battery can having one open side; an electrode terminal riveted through a through-hole formed at the bottom of the battery can; and a gasket disposed between the electrode terminal and an outer diameter of the through-hole, the electrode terminal includes a body portion inserted into the through-hole; an outer flange portion extending from around one side of the body portion exposed through the outer surface of the bottom portion along the outer surface; and an inner flange portion extending from around the other side of the body portion exposed through the inner surface of the bottom portion toward the inner surface, The gasket provides a rivet structure for the electrode terminal containing fluororesin.

[0042] A battery cell according to an embodiment of the present invention may include electrode terminals riveted to the bottom of the battery can.

[0043] FIG. 5 is a cross-sectional view showing the rivet structure of an electrode terminal 50 according to an embodiment of the present invention, and FIG. 6 is an enlarged cross-sectional view of the portion indicated by the dotted circle.

[0044] 5 and 6, the rivet structure of the electrode terminal 50 according to the embodiment may include a cylindrical battery can 51 having an open side, an electrode terminal 50 riveted through a through-hole 53 formed in a bottom 52 of the battery can 51, and a gasket 54 provided between the electrode terminal 50 and the outer circumference of the through-hole 53.

[0045] The battery can 51 is made of a conductive metal material. In one example, the battery can 51 may be made of a steel material, but the present invention is not limited thereto.

[0046] The electrode terminals 50 are made of a conductive metal material. In one example, the electrode terminals 50 may be made of aluminum, but the present invention is not limited thereto.

[0047] Preferably, the electrode terminal 50 may include a body portion 50a inserted into the through-hole 53, an external flange portion 50b extending from around one side of the body portion 50a exposed through the external surface 52a of the bottom 52 of the battery can 51 and along the external surface 52a, and an internal flange portion 50c extending from around the other side of the body portion 50a exposed through the internal surface 52b of the bottom 52 of the battery can 51 toward the internal surface 52b.

[0048] The gasket 54 includes a fluororesin. The fluororesin may be an insulating and / or elastic polymer resin. In one example, the fluororesin may include at least one selected from the group consisting of PFA (Perfluoroalkoxy) and PTFE (Polytetrafluoroethylene), but the present invention is not limited thereto.

[0049] In one example, the melting point of the fluororesin may be 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 fluororesin satisfies this range, the gasket does not melt even when the energy density of the battery cell increases, thereby preventing short circuits.

[0050] According to one embodiment of the present invention, there is provided a battery battery comprising: a battery can having one open side; an electrode terminal riveted through a through-hole formed at the bottom of the battery can; and a gasket disposed between the electrode terminal and an outer diameter of the through-hole, the electrode terminal includes a body portion inserted into the through-hole; an outer flange portion extending from around one side of the body portion exposed through the outer surface of the bottom portion along the outer surface; and an inner flange portion extending from around the other side of the body portion exposed through the inner surface of the bottom portion toward the inner surface, the gasket includes an outer gasket portion interposed between the outer flange portion and the outer surface of the bottom; and an inner gasket portion interposed between the inner flange portion and the inner surface of the bottom, The rivet structure for an electrode terminal is provided, wherein the change rate of the thickness of the outer gasket portion satisfies the following formula 1: [Formula 1] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 1, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 100° C. for 10 minutes.

[0051] According to one aspect, the gasket 54 may include an external gasket portion 54a interposed between the external flange portion 50b and the external surface 52a of the bottom 52 of the battery can 51, and an internal gasket portion 54b interposed between the internal flange portion 50c and the internal surface 52b of the bottom 52 of the battery can 51.

[0052] According to a further embodiment of the present invention, the rate of change in thickness of the outer gasket portion 54a may satisfy the following formula 1: [Formula 1] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 1, X1 is the thickness 54aT of the outer gasket portion at room temperature, and X2 is the thickness 54aT of the outer gasket portion when left at 100°C for 10 minutes.

[0053] The normal temperature may be a temperature selected from 20°C to 25°C, for example, 21°C to 24°C, 22°C to 23°C, or 23°C.

[0054] The thickness 54aT of the external gasket portion refers to the thickness in a direction perpendicular to the external surface 52a of the bottom of the battery can, and can be measured by taking an image of a cross section of the battery cell 201 cut in the longitudinal direction Y using a 3D shape measuring device.

[0055] FIG. 15 is a photograph showing a cross section of the rivet structure of the electrode terminal according to an embodiment of the present invention, cut along the longitudinal direction Y of the battery cell 201.

[0056] 15, in the rivet structure of the electrode terminal 50 including the outer gasket portion 54a, a cross section of a battery cell 201 including the electrode terminal 50 cut in the longitudinal direction Y can be measured using a 3D shape measuring device to measure the thickness 54aT of the outer gasket portion. In this case, the thickness 54aT of the outer gasket portion may be the thinnest part of the measured thicknesses.

[0057] The rate of change in thickness of the outer gasket portion 54a means the change in thickness of the outer gasket portion 54a depending on temperature and time. In the formula 1, the rate of change in thickness of the outer gasket portion 54a is preferably 10% or less.

[0058] In Equation 1, the thickness variation of the outer gasket portion 54a may be 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. The thickness variation of the outer gasket portion 54a may 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 of the outer gasket portion 54a satisfies the above range, a gasket 54 that does not melt due to the rivet structure of the electrode terminal can be provided, and a short circuit due to melting of the gasket between the electrode terminal and the battery can can be prevented.

[0059] According to one embodiment of the present invention, the gasket 54 provides a rivet structure for the electrode terminal containing fluororesin. By including the fluororesin, the gasket 54 can minimize variations in the thickness of the outer gasket portion 54a and prevent short circuits caused by melting of the gasket between the electrode terminal and the battery can.

[0060] According to one embodiment of the present invention, the gasket 54 includes an outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b interposed between the inner flange portion 50c and the inner surface of the bottom, and the thickness change rate of the outer gasket portion 54a may satisfy the following formula 2. [Formula 2] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 2, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 150° C. for 10 minutes.

[0061] As described above, the rate of change in thickness of the outer gasket portion 54a refers to the change in thickness of the outer gasket portion 54a depending on the temperature. By including a fluororesin in the gasket 54, the change in thickness of the outer gasket portion 54a can be minimized.

[0062] In Equation 2, the thickness variation of the outer gasket portion 54a may be 10% or less, 9.5% or less, 9% or less, 8.5% or less, 8% or less, 7.5% or less, or 7% or less. The thickness variation of the outer gasket portion 54a may be 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more. When the thickness variation of the outer gasket portion 54a satisfies the above ranges, a gasket 54 that does not melt due to the rivet structure of the electrode terminal can be provided, thereby preventing a short circuit caused by the gasket melting between the electrode terminal and the battery can.

[0063] According to one embodiment of the present invention, the gasket 54 includes an outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b interposed between the inner flange portion 50c and the inner surface of the bottom, and the thickness change rate of the outer gasket portion 54a may satisfy the following formula 3. [Formula 3] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 3, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 230° C. for 30 minutes.

[0064] As described above, the rate of change in thickness of the outer gasket portion 54a refers to the change in thickness of the outer gasket portion 54a due to temperature. By including a fluororesin in the gasket 54, the change in thickness of the outer gasket portion 54a can be minimized.

[0065] In Equation 3, the thickness variation of the outer gasket portion 54a may be 10% or less, 9.7% or less, 9.5% or less, 9.3% or less, or 9% or less. The thickness variation of the outer gasket portion 54a may 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 of the outer gasket portion 54a satisfies the above range, a gasket 54 that does not melt due to the rivet structure of the electrode terminal can be provided, and a short circuit due to melting of the gasket between the electrode terminal and the battery can can be prevented.

[0066] The [Formula 1] to [Formula 3] regarding the thickness change rate of the outer gasket portion 54a containing the fluororesin differ from the thickness change rate of the outer gasket portion not containing the fluororesin, as shown in Table 1 below.

[0067] [Table 1]

[0068] Referring to Table 1, the formulas 1 to 3 relate to the thickness change rate of the outer gasket part 54a containing a fluororesin, and the outer gasket part 54a may contain PFA (Perfluoroalkoxy), PTFE (Polytetrafluoroethylene), etc. When the formulas 1 to 3 satisfy the above ranges, the thickness change rate of the outer gasket part 54a is smaller than the thickness change rate of PP (Polypropylene) that does not contain a fluororesin, and therefore, a gasket 54 that is relatively resistant to melting in the rivet structure of the electrode terminal can be provided.

[0069] 13 is a photograph showing the phenomenon in which the conventional gasket melts due to the rivet structure of the electrode terminal in the comparative example of the present invention. In the case of the conventional gasket according to the embodiment of the present invention, the phenomenon of melting due to the inability to withstand the high temperature generated on the anode terminal side is observed.

[0070] 14 is a photograph showing the phenomenon in which the gasket containing the fluororesin according to the embodiment of the present invention does not melt due to the rivet structure of the electrode terminal. In the case of the gasket containing the fluororesin according to the embodiment of the present invention, the phenomenon in which the gasket melts is not observed even between the electrode terminal and the battery can, where high heat is generated in the battery cell.

[0071] According to an embodiment of the present invention, the gasket 54 may include a fluororesin, which may be an elastic polymer resin. For example, the fluororesin may include at least one selected from the group consisting of PFA (Perfluoroalkoxy) and PTFE (Polytetrafluoroethylene).

[0072] According to one embodiment of the present invention, the compressive strength of the fluororesin may be 10 MPa or more and 20 MPa or less. The compressive strength of the fluororesin can be measured by ASTM test method D695. The compressive strength of the fluororesin refers to the maximum stress before fracture when the fluororesin is subjected to a compressive force in a single direction, for example, a force applied to reduce the size of the fluororesin. It is expressed in terms of force per unit area (N / m2 or MPa). The compressive strength, as opposed to tensile strength, is the capacity of a material to resist compression by withstanding a load applied to reduce its size.

[0073] The compressive strength of the fluororesin may be 10.5 MPa or more, 11 MPa or more, 11.5 MPa or more, or 12 MPa or more. The compressive strength of the fluororesin may be 19.5 MPa or less, 19 MPa or less, 18.5 MPa or less, or 18 MPa or less. When the compressive strength of the fluororesin satisfies the above range, a gasket containing the fluororesin can be compressed well and retain elasticity even under high temperature conditions compared to a gasket containing PP (polypropylene) that does not contain a fluororesin. This allows the gasket to have excellent sealing strength even when subjected to a stronger compressive force during the manufacture of a rivet structure for an electrode terminal, thereby preventing leakage of electrolyte and gas.

[0074] According to one aspect, the electrode terminal 50 may further include a flat portion 50d provided at an end of the body portion 50a exposed through the inner surface 52b of the bottom portion 52 of the battery can 51.

[0075] Preferably, the flat portion 50d and the inner surface 52b of the bottom 52 of the battery can 51 may be parallel to each other. Here, "parallel" means that they are substantially parallel when observed with the naked eye.

[0076] According to one aspect, the angle θ between the inner flange portion 50c and the inner surface 52b of the bottom 52 of the battery can 51 may be 0° to 60° or less. The size of the angle is determined by the crimping strength when the electrode terminal 50 is installed in the through-hole 53 of the battery can 51 by a crimping method. In one example, as the crimping strength increases, the angle θ may decrease to 0°. If the angle exceeds 60°, the sealing effect of the gasket 54 may be reduced.

[0077] According to another aspect, a recess 55 may be provided between the inner flange portion 50c and the flat portion 50d. The recess 55 may have an asymmetric groove cross-sectional structure. In one example, the asymmetric groove may be substantially V-shaped. The asymmetric groove may include a sidewall 55a of the flat portion 50d and an inclined surface 55b of the inner flange portion 50c connected to an end of the sidewall 55a. The sidewall 55a may be substantially perpendicular to the inner surface 52b of the bottom 52 of the battery can 51. "Perpendicular" means substantially perpendicular when observed with the naked eye. The recess 55 is formed by the shape of a crimping jig when the electrode terminal 50 is fitted into the through-hole 53 of the battery can 51 by a crimping method.

[0078] Preferably, the thickness of the inner flange portion 50c may decrease as it moves away from the body portion 50a of the electrode terminal 50.

[0079] According to one embodiment of the present invention, the gasket 54 includes an outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface of the bottom; and an inner gasket portion 54b interposed between the inner flange portion 50c and the inner surface of the bottom, and the inner gasket portion 54b and the outer gasket portion 54a may have different thicknesses depending on their positions.

[0080] According to another aspect, the thickness of the outer gasket portion 54a and the inner gasket portion 54b may vary depending on the position. Preferably, the thickness of the inner gasket portion 54b may be relatively small in a region 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. Preferably, the minimum thickness point may be in the gasket region between the inner edge 56 of the through hole 53 and the inner flange portion 50c. Furthermore, the inner edge 56 of the through hole 53 may include an opposing surface 57 that faces the inner flange portion 50c.

[0081] Meanwhile, the upper and lower ends of the inner wall of the through hole 53 perpendicular to the bottom 52 of the battery can 51 are chamfered (corner cut) 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 may be deformed into a smooth curved surface having a curvature. In this case, the stress applied to the gasket 54 near the upper and / or lower ends of the inner wall of the through hole 53 can be further alleviated.

[0082] According to one embodiment of the present invention, the gasket 54 includes an outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface of the bottom, and an inner gasket portion 54b interposed between the inner flange portion 50c and the inner surface of the bottom, and the inner gasket portion 54b may extend longer than the inner flange portion 50c. Preferably, the inner gasket portion 54b may form an angle of 0° to 60° with the inner surface 52b of the bottom 52 of the battery can 51 and extend longer than the inner flange portion 50c.

[0083] In another aspect, the height H1 of the flat portion 50d relative to the inner surface 52b of the bottom 52 of the battery can 51 may be equal to or greater than the height H2 of the end of the internal gasket portion 54b. Also, the height H1 of the flat portion 50d relative to the inner surface 52b of the bottom 52 of the battery can 51 may be equal to or greater than the height H3 of the end of the internal flange portion 50c.

[0084] When the height parameters H1, H2, and H3 satisfy the above conditions, it is possible to prevent the inner flange portion 50c and the inner gasket portion 54b from interfering with other components.

[0085] In another aspect, the radius R1 from the center of the body portion 50a of the electrode terminal 50 to the edge of the outer flange portion 50b may be 10% to 60% of the radius R2 of the bottom portion 52 of the battery can 51 as the reference.

[0086] If R1 is small, there will be insufficient welding space when welding an electrical wiring component (bus bar) to the electrode terminal 50. If R1 is large, there will be less welding space when welding an electrical wiring component (bus bar) to the outer surface 52a of the bottom 52 of the battery can 51 excluding the electrode terminal 50.

[0087] By adjusting the ratio R1 / R2 between 10% and 60%, an appropriate welding space can be secured between the electrode terminal 50 and the outer surface of the bottom 52 of the battery can 51.

[0088] Furthermore, a radius R3 from the center of the body portion 50a of the electrode terminal 50 to the edge of the flat portion 50d may be 4 to 30% of the radius R2 of the bottom portion 52 of the battery can 51 as a reference.

[0089] If R3 is small, there will be insufficient welding space when welding the current collecting plate (see 79 in FIG. 11) to the flat portion 50d of the electrode terminal 50, reducing the welding area of ​​the electrode terminal 50 and increasing contact resistance. Also, R3 must be smaller than R1, and if R3 is large, the thickness of the inner flange portion 50c will be thin, weakening the force with which the inner flange portion 50c crimps the gasket 54 and possibly reducing the sealing ability of the gasket 54.

[0090] By adjusting R3 / R2 between 4% and 30%, a sufficient welding area can be secured between the flat portion 50d of the electrode terminal 50 and the current collecting plate (79 in FIG. 11), which not only facilitates the welding process but also reduces the contact resistance in the welding area and prevents a decrease in the sealing ability of the gasket 54.

[0091] According to one embodiment of the present invention, the rivet structure of the electrode terminal 50 may be formed using a crimping jig that moves up and down. First, a preform (not shown) of the electrode terminal 50 is inserted into a through-hole 53 formed in a bottom 52 of a battery can 51 with a gasket 54 interposed therebetween. The preform refers to the electrode terminal before being riveted.

[0092] Next, a crimping jig is inserted into the inner space of the battery can 51. The crimping jig has grooves and protrusions corresponding to the final shape of the electrode terminal 50 on the surface facing the preform, in order to rivet the preform to form the electrode terminal 50.

[0093] Next, the crimping jig is moved downward to pressurize and form the upper part of the preform, thereby transforming the preform into a riveted electrode terminal 50.

[0094] While the preform is compressed by the crimping jig, the outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface 52a of the bottom 52 of the battery can 51 is elastically compressed, reducing its thickness. Furthermore, the portion of the inner gasket portion 54b interposed between the inner edge 56 of the through-hole 53 and the preform is elastically compressed by the inner flange portion 50c, reducing its thickness more than other regions. In particular, the region where the thickness of the inner gasket portion 54b is reduced intensively is the portion indicated by the dotted circle in FIG. 6. This significantly improves the sealing and hermeticity between the riveted electrode terminal 50 and the battery can 51.

[0095] Preferably, the gasket 54 is compressed sufficiently to ensure the desired sealing strength without being physically damaged during the process of riveting the preform.

[0096] In one example, when the gasket 54 is made of polyfluoroethylene, the gasket 54 preferably has a compressibility of 60% or more at the point where it is compressed to its minimum thickness. The compressibility is the ratio of the change in thickness before and after compression to the thickness before compression.

[0097] Preferably, the crimping jig may be moved up and down at least two times to perform pressure forming of the upper part of the preform in stages. That is, the preform may be pressure formed in stages to deform it in multiple steps. At this time, the pressure applied to the crimping jig may be increased in stages. This distributes the stress applied to the preform multiple times, thereby preventing damage to the gasket 54 as the crimping process progresses. In particular, when the portion of the inner gasket portion 54b interposed between the inner edge portion 56 of the through hole 53 and the preform is compressed intensively by the inner flange portion 50c, damage to the gasket is minimized.

[0098] After pressure forming of the preform using the crimping jig is completed, the crimping jig is separated from the battery can 51, whereby the riveted structure of the electrode terminal 50 according to the embodiment of the present invention is obtained, as shown in FIG.

[0099] According to the above-described embodiment, the crimping jig presses and forms the upper part of the preform through up and down movement inside the battery can 51. In some cases, a rotary jig used in the prior art may be used for press-forming the preform.

[0100] However, the rotary rotation jig rotates at a predetermined angle with respect to the central axis of the battery can 51. Therefore, a rotary rotation jig with a large rotation radius may interfere with the inner wall of the battery can 51. Furthermore, if the battery can 51 is deep, the length of the rotary rotation jig also increases accordingly. In this case, the large rotation radius of the end of the rotary rotation jig may prevent proper pressure forming of the preform. Therefore, pressure forming using a crimping jig is more effective than a method using a rotary rotation jig.

[0101] The rivet structure of the electrode terminal 50 according to the embodiment of the present invention described above is applicable to a battery cell.

[0102] In one example, the battery cell may include a battery can 51. The battery can may be cylindrical. Its size may be a circular diameter at both ends of 30 mm to 55 mm and a height of 60 mm to 120 mm. Preferably, the circular diameter x height of the cylindrical battery can may be 46 mm x 60 mm, 46 mm x 80 mm, 46 mm x 90 mm, or 46 mm x 120 mm.

[0103] Preferably, the cylindrical battery cell may be, for example, a cylindrical battery cell having a form factor ratio (defined as the diameter divided by the height of the cylindrical battery cell, i.e., the ratio of the diameter Φ to the height H) greater than about 0.4.

[0104] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. Cylindrical battery cells according to an embodiment of the present invention may be, for example, 46110 cells, 48750 cells, 48110 cells, 48800 cells, 46800 cells, or 46900 cells. In the form factor value, the first two digits indicate the diameter of the cell, the next two digits indicate the height of the cell, and the final digit 0 indicates that the cell has a circular cross section.

[0105] A battery cell according to one embodiment of the present invention may be a cylindrical battery cell that is a substantially cylindrical cell, with a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0106] Another example battery cell may be a cylindrical battery cell that is a generally cylindrical cell, with a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0107] In another embodiment, the battery cell may be a cylindrical battery cell that is a substantially cylindrical battery with a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0108] In another embodiment, the battery cell may be a substantially cylindrical cell having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0109] Another example battery cell may be a cylindrical battery cell that is a generally cylindrical cell, with a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0110] In another embodiment, the battery cell may be a substantially cylindrical cell having a diameter of about 46 mm, a height of about 90 mm, and a form factor ratio of 0.511.

[0111] Conventionally, battery cells with a form factor ratio of approximately 0.4 or less have been used. For example, 18650 cells and 21700 cells have been used. 18650 cells have a diameter of approximately 18 mm and a height of approximately 65 mm, resulting in a form factor ratio of 0.277. 21700 cells have a diameter of approximately 21 mm and a height of approximately 70 mm, resulting in a form factor ratio of 0.300.

[0112] According to one embodiment of the present invention, there is provided a battery cell including: an electrode assembly in which sheet-like first and second electrode plates are wound with a separator interposed therebetween, and the electrode assembly includes an uncoated portion of the first electrode plate and an uncoated portion of the second electrode plate extending from both side edges and exposed; a rivet structure for an electrode terminal according to the above embodiment; and a sealing body, wherein the electrode assembly is housed inside a battery can, the first electrode plate and the battery can are electrically connected, and the second electrode plate and the electrode terminal are electrically connected, and the sealing body seals an open end of the battery can so as to be insulated from the battery can.

[0113] According to one embodiment of the present invention, the battery can of the battery cell includes a beading portion press-fitted into the inside of the battery can in a region adjacent to an open end, the sealing body includes a non-polar cap plate and a sealing gasket interposed between an edge of the cap plate and the open end of the battery can, and the battery can includes a crimping portion extending and bent into the inside of the battery can to wrap around and fix the edge of the cap plate together with the sealing gasket.

[0114] FIG. 7 is a cross-sectional view of a battery cell 70 according to an embodiment of the present invention taken along the longitudinal direction Y. As shown in FIG.

[0115] Referring to FIG. 7, a battery cell 70 according to an embodiment includes an electrode assembly 71 in which sheet-like first and second electrode plates are wound with a separator interposed therebetween, and includes an uncoated portion 72 of the first electrode plate and an uncoated portion 73 of the second electrode plate that extend from both side edges and are exposed.

[0116] In some embodiments, the first electrode plate may be a cathode plate and the second electrode plate may be an anode plate, or vice versa.

[0117] The method for winding the electrode assembly 71 is substantially the same as the method for winding an electrode assembly used in manufacturing a conventional table-less battery cell described with reference to FIG.

[0118] In the illustration of the electrode assembly 71, only the uncoated portions 72, 73 that are exposed and extend outside the separation membrane are shown in detail, and the winding structure of the first electrode plate, the second electrode plate, and the separation membrane is not shown.

[0119] The battery cell 70 also includes a battery can 51 that houses the electrode assembly 71 and is electrically connected to the uncoated portion 72 of the first electrode plate.

[0120] Preferably, one side (bottom) of the battery can 51 is open. The bottom 52 of the battery can 51 has a structure in which the electrode terminal 50 is riveted into the through-hole 53 through a crimping process.

[0121] The battery cell 70 may also include a gasket 54 provided between the electrode terminal 50 and the outer diameter of the through-hole 53 .

[0122] The battery cell 70 may also include a sealing body 74 that seals the open end of the battery can 51 so as to be insulated from the battery can 51. Preferably, the sealing body 74 may include a non-polar cap plate 74a and a sealing gasket 74b interposed between the edge of the cap plate 74a and the open end of the battery can 51.

[0123] The cap plate 74a may be made of a conductive metal material such as aluminum, steel, or nickel. The sealing gasket 74b may be made of an insulating and elastic material such as polypropylene, polybutylene terephthalate, or polyethylene fluoride. However, the present invention is not limited by the materials of the cap plate 74a and the sealing gasket 74b.

[0124] The cap plate 74a may include vent notches 77 that rupture when the pressure inside the battery can 51 exceeds a threshold. The vent notches 77 may be formed on both sides of the cap plate 74a. The vent notches 77 may form a continuous or discontinuous circular pattern, a linear pattern, or other pattern on the surface of the cap plate 74a.

[0125] The battery can 51 may include a crimping portion 75 that extends inward of the battery can 51 and is bent to wrap around and fix the edge of the cap plate 74a together with the sealing gasket 74b in order to secure the sealing body 74.

[0126] The battery can 51 may also include a beading portion 76 press-fitted into the inside of the battery can 51 in a region adjacent to the open end. The beading portion 76 supports the edge of the sealing body 74, particularly the outer peripheral surface of the sealing gasket 74b, when the sealing body 74 is fixed by the crimping portion 75.

[0127] The battery cell 70 may further include a first current collecting plate 78 welded to the uncoated portion 72 of the first electrode plate. The first current collecting plate 78 is made of a conductive metal material such as aluminum, steel, or nickel. Preferably, at least a portion 78a of the edge of the first current collecting plate 78 that does not contact the uncoated portion 72 of the first electrode plate may be interposed between the beading portion 76 and the sealing gasket 74b and fixed by the crimping portion 75. Optionally, at least a portion 78a of the edge of the first current collecting plate 78 may be fixed to the inner circumferential surface 76a of the beading portion 76 adjacent to the crimping portion 75 by welding.

[0128] The battery cell 70 may also include a second current collecting plate 79 welded to the uncoated portion 73 of the second electrode plate. Preferably, at least a portion of the second current collecting plate 79, for example, a central portion 79a, may be welded to the flat portion 50d of the electrode terminal 50.

[0129] Preferably, when welding the second current collecting plate 79, a welding tool may be inserted through the winding core 80 present in the core of the electrode assembly 71 and reach the welding point of the second current collecting plate 79. Furthermore, when the second current collecting plate 79 is welded to the flat portion 50d of the electrode terminal 50, the electrode terminal 50 supports the welding area of ​​the second current collecting plate 79, allowing for strong pressure to be applied to the welding area, improving welding quality. Furthermore, the flat portion 50d of the electrode terminal 50 has a large area, allowing for a large 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 between the riveted electrode terminal 50 and the second current collecting plate 79 is very useful for rapid charging using a high-c-rate current. This is because it reduces the current density per unit area in the cross section in the current flow direction, thereby reducing the amount of heat generated in the current path compared to conventional methods.

[0130] The flat portion 50d of the electrode terminal 50 can be welded to the second current collecting plate 79 by any of laser welding, ultrasonic welding, spot welding, and resistance welding. The area of ​​the flat portion 50d can be adjusted depending on the welding method, but is preferably 2 mm or more for the sake of weld strength and ease of the welding process.

[0131] In one example, when the flat portion 50d and the second current collecting plate 79 are welded by a laser in a circular pattern, either continuous or discontinuous, the diameter of the flat portion 50d is preferably 4 mm or greater. If the diameter of the flat portion 50d satisfies this condition, the welding strength can be ensured, and there is no difficulty in inserting a laser welding tool into the winding core 80 of the electrode assembly 71 and proceeding with the welding process.

[0132] In another example, when the flat portion 50d and the second current collecting plate 79 are ultrasonically welded in a circular pattern, the diameter of the flat portion 50d is preferably 2 mm or more. If the diameter of the flat portion 50d satisfies this condition, the welding strength can be ensured, and there is no difficulty in inserting the ultrasonic welding tool into the winding core 80 of the electrode assembly 71 and proceeding with the welding process.

[0133] The battery cell 70 may further include an insulating cap 80'. The insulating cap 80' may be interposed between the second current collecting plate 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 cap 80' includes a welding hole 80a that exposes the flat portion 50d of the electrode terminal 50 to the second current collecting plate 79, and may cover the surface of the second current collecting plate 79 and the edge of one side (top) of the electrode assembly 71.

[0134] Preferably, the uncoated portions 72, 73 of the first electrode plate and / or the second electrode plate may be bent from the outer periphery side of the electrode assembly 71 toward the core side, thereby forming bent surfaces at the top and bottom of the electrode assembly 71. Furthermore, the first current collecting plate 78 may be welded to the bent surface formed by bending the uncoated portion 72 of the first electrode plate, and the second current collecting plate 79 may be welded to the bent surface formed by bending the uncoated portion 73 of the second electrode plate.

[0135] In order to relieve stress that occurs when the uncoated portions 72, 73 are bent, the first electrode plate and / or the second electrode plate may have an improved structure that differs from conventional electrode plates (see FIG. 1).

[0136] FIG. 8 is a plan view illustrating the structure of an electrode plate 90 according to a preferred embodiment of the present invention.

[0137] Referring to FIG. 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 surface of the current collector 91, and a plain portion 93 on the long edge of the current collector 91 where no active material is coated.

[0138] Preferably, the plain portion 93 may include a plurality of notched segment pieces 93a. The plurality of segment pieces 93a may be arranged in a plurality of groups, and the segment pieces 93a in each group may have the same height (length in the Y direction) and / or width (length in the X direction) and / or spacing pitch. The number of segment pieces 93a in each group may be greater or less than that shown in the figure. The segment pieces 93a may be trapezoidal, or may be deformed into a rectangle, a balanced quadrilateral, a semicircle, or a semi-ellipse.

[0139] Preferably, the height of the segment pieces 93a may increase stepwise from the core side toward the outer periphery. Also, the core-side uncoated area 93' adjacent to the core side may not include segment pieces 93a, and the height of the core-side uncoated area 93' may be smaller than the height of the other uncoated areas.

[0140] Optionally, the electrode plate 90 may include an insulating coating layer 94 covering the boundary between the active material layer 92 and the uncoated portion 93. The insulating coating layer 94 includes an insulating polymer resin and may optionally further include an inorganic filler. The insulating coating layer 94 prevents the end of the active material layer 92 from contacting the active material layer of the opposite polarity that faces the separator, and serves to structurally support the bending of the segment pieces 93a. For this purpose, it is preferable that at least a portion of the insulating coating layer 94 be exposed to the outside through the separator when the electrode plate 90 is wound into an electrode assembly.

[0141] FIG. 9 is a cross-sectional view taken along the longitudinal direction Y of an electrode assembly 100 in which the segmented structure of the uncoated portion of the electrode plate 90 according to an embodiment of the present invention is applied to the first and second electrode plates.

[0142] 9, the electrode assembly 100 may be manufactured by the winding method described with reference to FIG. 2. For ease of explanation, the protruding structure of the uncoated portions 72 and 73 extending outward from the separator is shown in detail, and the winding structure of the first electrode plate, the second electrode plate, and the separator is not shown. The uncoated portion 72 protruding downward extends from the first electrode plate, and the uncoated portion 73 protruding upward extends from the second electrode plate.

[0143] The diagrams show patterns in which the heights of the uncoated portions 72, 73 vary schematically. That is, the heights of the uncoated portions 72, 73 may vary irregularly depending on the location where the cross section is cut. For example, when a side portion of the trapezoidal segment 93a is cut, the height of the uncoated portion in the cross section becomes lower than the height of the segment 93a. Therefore, it should be understood that the heights of the uncoated portions 72, 73 shown in the cross-sectional view of the electrode assembly 100 correspond to the average height of the uncoated portions included in each winding pattern.

[0144] As shown in FIG. 10, the uncoated portions 72 and 73 may be folded from the outer periphery of the electrode assembly 100 toward the core. In FIG. 9, the folded portion 101 is indicated by a dashed box. When the uncoated portions 72 and 73 are folded, adjacent segments overlap each other in the radial direction, forming folded surfaces 102 at the top and bottom of the electrode assembly 100. The core-side uncoated portion (93' in FIG. 8) is too low to be folded. The height h of the segment bending from the innermost side is equal to or smaller than the radial length r of the winding region formed by the core-side uncoated portion 93' without a segment structure. Therefore, the winding core 80 in the core of the electrode assembly 100 is not closed by the folded segments. If the winding core 80 is not closed, the electrolyte injection process is not difficult and the efficiency of electrolyte injection is improved. Furthermore, by inserting a welding tool through the winding core 80, the electrode terminal 50 and the second current collecting plate 79 can be easily welded together.

[0145] In the battery cell 70 according to the embodiment of the present invention, the cap plate 74a of the sealed body 74 does not have a polarity. Instead, the first current collecting plate 78 is connected to the side wall of the battery can 51, and the outer surface 52a of the bottom 52 of the battery can 51 has the opposite polarity to the electrode terminal 50. Therefore, when connecting multiple cells in series and / or parallel, wiring such as a bus bar connection can be performed at the top of the battery cell 70 using the outer surface 52a of the bottom 52 of the battery can 51 and the electrode terminal 50. This increases the number of cells that can be mounted in the same space, thereby improving energy density.

[0146] 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 may be any active material known in the art without any limitation.

[0147] In one example, the positive electrode active material has the general formula A[A × 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 x, y, z, and the components included in M ​​are selected to maintain electroneutrality of the compound).

[0148] In another example, the positive electrode active material is an alkali metal compound xLiM, as disclosed in U.S. Pat. No. 6,677,082, U.S. Pat. No. 6,680,143, and the like. 1 O2-(1-x)Li 2M 2 O3(M 1 contains at least one element having an average oxidation state of 3; M 2 may comprise at least one element having an average oxidation state of 4; 0≦x≦1).

[0149] In still other examples, the positive electrode active material has the general formula Lia M 1× Fe 1-x M 2 P y1-y M 3 z O 4-z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 contains halogen elements, optionally including F; 0 <a≦2,0≦×≦1,0≦y<1、0≦z<1;a、x、y、z、M 1 , M 2 , and M 3 wherein the stoichiometric coefficients of the components in are selected to maintain electroneutrality of the compound), or lithium metal phosphate represented by Li3M2(PO4)3, where M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al.

[0150] Preferably, the positive electrode active material may contain primary particles and / or secondary particles formed by aggregation of the primary particles.

[0151] In one example, the negative electrode active material may be a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, or tin or a tin compound. Metal oxides with a potential of less than 2 V, such as TiO2 and SnO2, may also be used as the negative electrode active material. The carbon material may be either low-crystalline carbon or high-crystalline carbon.

[0152] The separation membrane may be a porous polymer film, such as a porous polymer film made from a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, either alone or in combination. Alternatively, the separation membrane may be made of a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber or polyethylene terephthalate fiber.

[0153] At least one surface of the separator may include a coating layer of inorganic particles.

[0154] Alternatively, the separator itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder so that interstitial volume exists between adjacent particles.

[0155] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. Non-limiting examples of the inorganic particles include 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, hafnia(HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO 2、 It may contain at least one material selected from the group consisting of MgO, CaO, ZnO and Y2O3.

[0156] The electrolyte is A + B - The salt may have the following structure: + Li + , Na + , K. + and ions consisting of alkali metal cations such as B - is 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 - The anion comprises one or more anions selected from the group consisting of:

[0157] The electrolyte may also be dissolved in an organic solvent, such as 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), gamma butyrolactone, or a mixture thereof.

[0158] The cylindrical battery cells according to the above embodiments may be used to manufacture a battery pack.

[0159] FIG. 11 is a diagram schematically illustrating the configuration of a battery pack according to an embodiment of the present invention.

[0160] 11 , a battery pack 200 according to an embodiment of the present invention includes an assembly of electrically connected cylindrical battery cells 201 and a pack housing 202 that accommodates the assembly. The cylindrical battery cells 201 are the battery cells according to the above-described embodiment. For ease of illustration, components such as bus bars for electrically connecting the cylindrical battery cells 201, a cooling unit, and external terminals are omitted from the drawing.

[0161] The battery pack 200 may be installed in a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle may be a four-wheeled vehicle or a two-wheeled vehicle.

[0162] FIG. 12 is a diagram illustrating a vehicle including the battery pack 200 of FIG.

[0163] 12, a vehicle V according to an embodiment of the present invention includes a battery pack 200 according to an embodiment of the present invention. The vehicle V is operated by receiving power from the battery pack 200 according to an embodiment of the present invention. [Example]

[0164] [Example 1] (1) Fabrication of rivet structure for electrode terminal The battery can (diameter: 45 mm to 47 mm, material: steel) had one side open, and an electrode terminal was used that was riveted in a crimping process into a through-hole formed in the bottom of the battery can.

[0165] In the rivet structure of the electrode terminal including the riveted electrode terminal, the electrode terminal included a 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, and a gasket containing PFA (Perfluoroalkoxy) was provided between the electrode terminal and the outer diameter of the through-hole to fabricate the rivet structure of the electrode terminal. The outer diameter of the gasket was 16 mm, and the thickness of the outer gasket portion interposed between the outer flange portion and the outer surface of the bottom was 0.5 mm.

[0166] (2) Battery cell fabrication The sheet-shaped cathode, polyethylene separator, and anode were sequentially stacked and wound to prepare an electrode assembly. The wound electrode assembly was inserted into a battery can having the rivet structure of the electrode terminal, and an electrolyte was poured into the battery can. The cylindrical battery can was then sealed with a seal to prepare a battery cell.

[0167] In the battery cell, the negative electrode plate of the electrode assembly was electrically connected to the battery can, the positive electrode plate was electrically connected to the electrode terminal, and the sealed body was insulated from the battery can.

[0168] [Comparative Example 1] An electrode terminal including a rivet structure and a battery cell including the same were produced in the same manner as in Example 1, except that in the rivet formation structure of the electrode terminal, a gasket including PP (Polypropylene) was provided between the electrode terminal and the outer diameter of the through hole.

[0169] [Experimental Example] (Experimental Example 1: Measuring the rate of change in thickness of the outer gasket) The change rate of the thickness of the outer gasket part was calculated by measuring the thickness (X1) of the outer gasket part at room temperature (23°C), leaving it at 100°C for 10 minutes, and then measuring the thickness (X2) of the outer gasket part again, and calculating the difference between the thickness (X1) of the outer gasket part at room temperature and the thickness (X2) of the outer gasket part at a temperature higher than room temperature.

[0170] The formula for calculating the rate of change in thickness of the outer gasket part is as follows:

[0171] Change rate of outer gasket thickness (%) = [(X1-X2) / X1] x 100

[0172] In the formula for calculating the rate of change in the thickness of the outer gasket part, the thickness (X2) of the outer gasket part was measured again after leaving it at 150°C for another 10 minutes, and the thickness (X2) of the outer gasket part was measured again after leaving it at 230°C for 30 minutes, and the rate of change in the thickness of the outer gasket part was calculated.

[0173] Under each temperature and time condition, the thickness (X1) of the outer gasket portion at room temperature and the thickness (X2) of the outer gasket portion at a temperature higher than room temperature were measured and shown in Table 2.

[0174] The thickness (X1, X2) of the external gasket portion was measured using a 3D shape measuring device (Keyence shape measuring device, model name: Keyence Corea VR5000). The thickness (X1, X2) of the external gasket portion was recorded as the average value of three measurements of the thinnest portion (54aT) of the external gasket portion measured in an image of a cross section of a battery cell including the external gasket portion cut in the longitudinal direction Y, taken with the 3D shape measuring device. The battery cell was cut using a molding device, a polishing device (model name: Tegramin-30) for polishing the cell, and a grinder for cutting from the diameter of the end of the battery cell in the longitudinal direction Y of the battery cell.

[0175] [Table 2]

[0176] The change rate of the thickness of the outer gasket portion was calculated from the measured values ​​of the thickness (X1) of the outer gasket portion at room temperature and the thickness (X2) of the outer gasket portion at a temperature higher than room temperature, and is shown in Table 3.

[0177] [Table 3]

[0178] Referring to Tables 2 and 3, it can be seen that the thickness change rate of the outer gasket portion containing fluororesin satisfies the range of 10% or less, and therefore the thickness change rate of the outer gasket portion of the gasket containing PFA (Perfluoroalkoxy) is smaller than the thickness change rate of the outer gasket portion of the gasket containing PP (Polypropylene). As a result, it can be confirmed that a gasket that is relatively non-melting due to the rivet structure of the electrode terminal can be provided, and short circuits due to melting of the gasket between the electrode terminal and the battery can can be prevented.

[0179] Although the present invention has been described above using limited examples and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary skill in the art to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims set forth below. [Explanation of symbols]

[0180] 10...Anode plate 11 Cathode plate 10a: Uncoated portion of anode plate 11a: Uncoated portion of cathode plate 12...Separation membrane 20 Current collector 21...Active material 22 Plain area 30, 31: Current collecting plates 40 Tableless Battery Cell 41 Battery can 42... Sealed body 42a Cap plate 42b Sealing gasket 42c...connecting plate 43 Crimping section 44 Beading section 45... Lead 46 Insulator A...electrode assembly 50...electrode terminal 50a Body 50b: External flange 50c Internal flange 50d...Flat area 51 Cylindrical battery can with one side open 51a: Inner surface of the side wall of the battery can 52...Bottom 52a External surface 52b ···Internal surface 53 Through hole 54 Gasket 54a: External gasket part 54aT: Thickness of outer gasket 54b Internal gasket part 55 Recessed part 55a Side wall of flat section 55b: Inclined surface of inner flange 56 Inner edge of through hole 57. The surface facing the internal flange 70 Battery Cells 71...electrode assembly 72 Uncoated portion of first electrode plate 73 Uncoated portion of second electrode plate 74...Sealed body 74a Cap plate 74b Sealing gasket 75 Crimping part 76 Beading section 76a: Inner surface of beading portion 77 ···Vent Notch 78 First current collecting plate 78a: Edge of first current collecting plate 79 Second current collecting plate 79a...Central part 80 ··· Winding core 80' Insulating Cap 80a...welding hole 90...electrode plate 91 Current collector 92...Active material layer 93 Plain area 93' Plain area on core side 93a...segmental piece 94 Insulating coating layer 100...electrode assembly 101....Foldable part 102....Bending surface 200 Battery Pack 201 Cylindrical battery cell 202 Pack Housing

Claims

1. Battery can open on one side; an electrode terminal riveted through a through-hole formed in the bottom of the battery can; and a gasket provided between the electrode terminal and the outer diameter of the through hole; The electrode terminal is a body portion inserted into the through hole; an external flange portion extending around one side of the body portion exposed through the exterior surface of the bottom portion and along the exterior surface; and an internal flange portion extending from around the other side of the body portion exposed through the internal surface of the bottom portion toward the internal surface; The gasket is made of a fluororesin, the gasket includes an internal gasket portion interposed between the internal flange portion and the internal surface of the bottom portion; The inner gasket portion forms an angle of 60° or less with the inner surface.

2. 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 provided between the electrode terminal and the outer diameter of the through hole; The electrode terminal is a body portion inserted into the through hole; an external flange portion extending around one side of the body portion exposed through the exterior surface of the bottom portion and along the exterior surface; and an internal flange portion extending from around the other side of the body portion exposed through the internal surface of the bottom portion toward the internal surface; the gasket includes an outer gasket portion interposed between the outer flange portion and the outer surface of the bottom; and an inner gasket portion interposed between the inner flange portion and the inner surface of the bottom, the gasket contains a fluororesin, The change rate of the thickness of the outer gasket portion satisfies the following formula 1: a rivet structure of an electrode terminal, wherein the internal gasket portion forms an angle of 60° or less with the internal surface; [Formula 1] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 1, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 100° C. for 10 minutes.

3. the gasket includes an outer gasket portion interposed between the outer flange portion and an outer surface of the bottom portion; 3. The rivet structure of claim 1, wherein the change rate of the thickness of the outer gasket portion satisfies the following formula 2: [Formula 2] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 2, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 150° C. for 10 minutes.

4. the gasket includes an outer gasket portion interposed between the outer flange portion and an outer surface of the bottom portion; 3. The rivet structure of an electrode terminal according to claim 1, wherein the change rate of the thickness of the outer gasket portion satisfies the following formula 3: [Formula 3] 0%≦[(X1-X2) / X1]×100(%)≦10% In the formula 3, X1 is the thickness of the outer gasket portion at room temperature, and X2 is the thickness of the outer gasket portion when left at 230° C. for 30 minutes.

5. 3. The rivet structure of an electrode terminal according to claim 2, wherein the gasket is made of a fluororesin.

6. 6. The rivet structure of an electrode terminal according to claim 1, wherein the melting point of the fluororesin is 280°C or higher.

7. 6. The rivet structure of an electrode terminal according to claim 1, wherein the fluororesin includes at least one selected from the group consisting of PFA (Perfluoroalkoxy) and PTFE (Polytetrafluoroethylene).

8. The rivet structure of an electrode terminal according to claim 1 , 2 or 5 , wherein the electrode terminal further comprises a flat portion provided on an end of the body portion exposed through the inner surface of the bottom portion.

9. The rivet structure of an electrode terminal according to claim 8 , wherein the inner surfaces of the flat portion and the bottom portion are parallel to each other.

10. 6. The rivet structure of an electrode terminal according to claim 1, wherein an angle between the inner flange portion and the inner surface of the bottom portion is 0° to 60°.

11. The rivet structure of an electrode terminal according to claim 8 , wherein a recess is provided between the inner flange portion and the flat portion.

12. The rivet structure of an electrode terminal according to claim 11 , wherein the recess portion has an asymmetric groove cross-sectional structure.

13. The rivet structure of an electrode terminal according to claim 12 , wherein the asymmetric groove includes a side wall of the flat portion and an inclined surface of the inner flange portion connected to an end of the side wall.

14. The rivet structure of an electrode terminal according to claim 13 , wherein the side wall is perpendicular to the inner surface of the bottom portion.

15. 6. The rivet structure of an electrode terminal according to claim 1, wherein the thickness of the inner flange portion decreases with increasing distance from the body portion.

16. the gasket includes an outer gasket portion interposed between the outer flange portion and an outer surface of the bottom portion; 6. The rivet structure of an electrode terminal according to claim 1, wherein the inner gasket portion and the outer gasket portion have different thicknesses depending on the position.

17. 17. The rivet structure of an electrode terminal according to claim 16, wherein a thickness of a region of the internal gasket portion between the inner edge of the through hole connected to the inner surface of the bottom portion and the internal flange portion is relatively smaller than that of other regions.

18. The rivet structure of an electrode terminal according to claim 17 , wherein an inner edge of the through hole includes an opposing surface facing the inner flange portion.

19. the gasket includes an outer gasket portion interposed between the outer flange portion and an outer surface of the bottom portion; 6. The rivet structure of an electrode terminal according to claim 1, wherein the inner gasket portion extends longer than the inner flange portion.

20. 9. The rivet structure of an electrode terminal according to claim 8, wherein the height of the flat portion relative to the inner surface of the bottom portion is equal to or greater than the height of an end of the inner gasket portion.

21. 9. The rivet structure of an electrode terminal according to claim 8, wherein the height of the flat portion relative to the inner surface of the bottom portion is equal to or greater than the height of the end of the inner flange portion.

22. 6. The rivet structure of an electrode terminal according to claim 1, wherein a radius from the center of the body portion to the edge of the outer flange portion is 10% to 60% of a radius of the base portion.

23. 9. The rivet structure of an electrode terminal according to claim 8, wherein a radius from the center of the body portion to the edge of the flat portion is 4% to 30% of the radius of the bottom portion.

24. 3. A battery cell comprising: an electrode assembly in which sheet-like first and second electrode plates are wound with a separator interposed therebetween, the electrode assembly including uncoated portions of the first and second electrode plates extending from both side edges and exposed; the rivet structure for an electrode terminal according to claim 1 or 2; and a sealed body, the electrode assembly is housed inside a battery can, the first electrode plate and the battery can are electrically connected, and the second electrode plate and the electrode terminal are electrically connected; The sealing body seals the open end of the battery can so as to be insulated from the battery can.

25. the battery can includes a beading portion press-fitted into the inside of the battery can in a region adjacent to the open end, the sealing body includes a non-polar cap plate and a sealing gasket interposed between an edge of the cap plate and an open end of the battery can; The battery cell of claim 24 , wherein the battery can includes a crimping portion that extends and is bent inside the battery can to enclose and fix an edge of the cap plate together with the sealing gasket.

26. 26. The battery cell of claim 25, wherein the cap plate includes a vent notch that ruptures when pressure inside the battery can exceeds a threshold value.

27. a first current collecting plate welded to the uncoated portion of the first electrode plate; 26. The battery cell of claim 25, wherein at least a portion of an edge of the first current collecting plate that does not contact the plain portion of the first electrode plate is interposed between the beading portion and the sealing gasket and is fixed by the crimping portion.

28. 28. The battery cell of claim 27, wherein at least a portion of an edge of the first current collecting plate is secured to an inner circumferential surface of the beading portion adjacent the crimping portion by welding.

29. a second current collecting plate welded to the uncoated portion of the second electrode plate; 25. The battery cell according to claim 24, wherein at least a portion of the second current collecting plate is welded to a flat portion of the electrode terminal.

30. the battery further includes insulating caps interposed between the second current collecting plate and an inner circumferential surface of the bottom of the battery can, and between an inner circumferential surface of the side wall of the battery can and the electrode assembly, 30. The battery cell of claim 29, wherein the insulating cap includes a welding hole that exposes a flat portion of the electrode terminal toward the second current collecting plate, and covers a surface of the second current collecting plate and an edge on one side of the electrode assembly.

31. A battery pack comprising at least one battery cell according to claim 24.

32. 32. A motor vehicle comprising at least one battery pack according to claim 31.

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