Electrode assembly, battery cell, battery pack, and automobile

Abstract

The present invention provides an electrode assembly in which a first electrode, a separator, and a second electrode are stacked and wound, wherein at least one of the first electrode and the second electrode includes a current collector and an electrode active material layer provided on the current collector, and the first electrode includes the electrode active material layer and a fixing portion provided on an edge of the electrode assembly closest to the center of the winding and fixed to at least a portion of the separator.The present invention also provides a battery cell including the electrode assembly, a battery can having an opening on one side that houses the electrode assembly, an electrode terminal riveted through a through-hole formed in the bottom of the battery can, a gasket provided between the electrode terminal and the outer diameter of the through-hole, and a sealing body that seals the opening of the battery can.

Description

[Technical field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0045993 filed with the Korean Intellectual Property Office on April 8, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly, a battery cell, a battery pack, and an automobile. [Background technology]

[0003] Secondary batteries, which have high ease of application depending on the product group and 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) that are powered by electrical sources.

[0004] Such secondary batteries have the primary advantage of dramatically reducing the use of fossil fuels, as well as the advantage of not producing any by-products from the use of energy, making them environmentally friendly and drawing attention as a new energy source for improving energy efficiency.

[0005] Currently, the types of secondary batteries that are widely used 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 about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack may be configured by connecting a plurality of battery cells in series. Also, a battery pack may be configured by connecting a plurality of battery cells in parallel according to the charge / discharge capacity required for the battery pack. Therefore, the number and electrical connection form of the battery cells included in the battery pack may be variously set according to the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, cylindrical, rectangular and pouch-shaped battery cells are known as types of secondary battery cells. The battery cell may be a cylindrical battery cell. The battery cell is formed by rolling up an electrode assembly in the form of a jelly roll, with an insulating separator interposed between an anode and a cathode, and inserting the electrode assembly into a battery can together with an electrolyte to form a battery. A strip-shaped electrode tab may be connected to each uncoated portion of the anode and cathode, and the electrode tab electrically connects the electrode assembly to an electrode terminal exposed to the outside. The electrode terminal of the anode is a cap plate of a sealed body that seals the opening of the battery can, and the electrode terminal of the cathode is the battery can.

[0007] However, in conventional battery cells having such a structure, current is concentrated at the strip-shaped electrode tabs coupled to the anode uncoated portion and / or cathode uncoated portion, resulting in problems such as high resistance, large heat generation, and poor current collection efficiency.

[0008] Resistance and heat generation are not a big issue for small cylindrical battery cells with a form factor 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 these problems, a battery cell (so-called tab-less battery cell) has been proposed, which is designed to have anode uncoated areas and cathode uncoated areas located at the top and bottom of a jelly roll-type electrode assembly, respectively, and has a structure in which current collecting plates are welded to these uncoated areas to improve current collection efficiency.

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

[0011] The first electrode may be a cathode and the second electrode may be an anode, and the cathode may include a cathode plate and the anode may include an anode plate.

[0012] 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-coated portion 22 on one long side along the winding direction X.

[0013] 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 Fig. 2, and then winding them up 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.

[0014] 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 folded toward the core side. Then, the uncoated portions 10a and 11a are welded to the current collecting plates 30 and 31, respectively.

[0015] No separate electrode tabs are attached to the positive electrode uncoated region 10a and the negative electrode uncoated region 11a, and the current collecting plates 30 and 31 are connected to external electrode terminals, and a current path is formed with a large cross-sectional area along the direction of the winding shaft of the electrode assembly A (see arrow), which has the advantage of lowering the resistance of the battery cell. This is because resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0016] However, as the form factor of cylindrical battery cells increases and the magnitude of charging current during fast charging increases, the heat generation problem occurs again in table-less battery cells.

[0017] Specifically, a conventional tab-less battery cell 40 includes a battery can 41 and a sealing body 42, as shown in Fig. 4. 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 inside the battery can 41 by a beading portion 44 to prevent vertical movement.

[0018] Typically, the positive terminal is the cap plate 42a of the sealed body 42, and the negative terminal is the battery can 41. Thus, the current collecting plate 30 coupled to the uncoated portion 10a of the positive plate 10 is electrically connected to a 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 plate 11 is electrically connected to the bottom of the battery can 41. The insulator 46 covers the current collecting plate 30 and prevents the battery can 41 and the uncoated portion 10a of the positive plate 10, which have opposite polarities, from coming into contact with each other and causing a short circuit.

[0019] 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 attached separately to the current collecting plate 30 or is made integral 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 current for rapid charging flows through it. In addition, the excess heat generated from the lead 45 is transferred to the electrode assembly A side and causes the separator 12 to shrink, which may cause an internal short circuit, which is a main cause of thermal runaway.

[0020] Furthermore, in order to connect the conventional tab-less battery cells 40 in series and / or parallel, it is necessary to connect bus bar components to the cap plate 42a of the sealed body 42 and the bottom surface of the battery can 41, resulting in poor space efficiency. A battery pack mounted on an electric vehicle includes several hundred battery cells 40. Therefore, the inefficiency of electrical wiring causes considerable complication during the assembly process of the electric vehicle and during maintenance of the battery pack. Summary of the Invention [Problem to be solved by the invention]

[0021] A technical object of the present invention is to prevent a separator from shrinking due to high temperatures by providing an electrode of an electrode assembly with a fixing portion that is fixed to the separator, without having a structure in which a cathode tab is attached to a core region of the electrode assembly.

[0022] Another technical object of the present invention, which has been devised under the background of the above-mentioned conventional technology, is to improve the structure of the electrode terminal of the battery cell to improve the space efficiency within the battery can, thereby reducing the internal resistance of the battery cell and increasing the energy density.

[0023] Another technical object of the present invention is to improve the structure of the electrode terminal of the battery cell to increase the cross-sectional area of ​​the current path, thereby improving the problem of internal heat generation that occurs during fast charging.

[0024] Another technical object of the present invention is to provide a battery cell having 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.

[0025] It is still another technical object of the present invention to provide a battery pack manufactured using a battery cell having an improved structure, and a vehicle including the battery pack.

[0026] However, the technical problems that the present invention aims to solve are not limited to the problems mentioned above, 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]

[0027] One embodiment of the present invention provides an electrode assembly in which a first electrode, a separator, and a second electrode are stacked and wound up, at least one of the first electrode and the second electrode includes a current collector and an electrode active material layer provided on the current collector, and the first electrode includes the electrode active material layer, which is provided on an edge portion closest to a winding center of the electrode assembly, and includes a fixing portion fixed to at least a part of the separator.

[0028] Another embodiment of the present invention provides a battery cell including: the electrode assembly according to the above embodiment; a battery can having an opening on one side for accommodating the electrode assembly; an electrode terminal riveted through a through hole formed in a bottom of the battery can; a gasket provided between the electrode terminal and an outer diameter of the through hole; and a sealing body for sealing the opening of the battery can.

[0029] Yet another embodiment of the present invention provides a battery pack including the battery cell according to the above embodiment.

[0030] Yet another embodiment of the present invention provides a vehicle including a battery pack according to the above embodiment. Effect of the Invention

[0031] When the outer diameter of the electrode assembly of a battery cell is small, it is not difficult for the internal heat to escape to the outside. However, in a battery cell that requires high capacity and high output, the outer diameter of the electrode assembly becomes larger, slowing down the speed at which heat escapes from the core to the outside.

[0032] If heat cannot be effectively removed from the core in this way, the rate of heat release will decrease, causing the separator to shrink due to high temperatures in the core, which may result in the separator being unable to function normally between the anode and cathode.

[0033] In the case of a cylindrical battery cell, a cathode tab may be attached to the core portion. In this case, even if the separator is thermally damaged from the core and shrinks, the cathode tab can function to physically fix the separator.

[0034] However, in the case of an electrode assembly that does not have a cathode tab that can physically prevent the shrinkage of the separator, the electrode assembly may be vulnerable to problems associated with the shrinkage of the separator.

[0035] According to one aspect of the present invention, a fixing part that is fixed to a separator is provided on an electrode of an electrode assembly, thereby preventing the separator from shrinking due to high temperatures without having a structure in which a cathode tab is attached to a core region of an electrode assembly.

[0036] According to another aspect of the present invention, by solving the above-mentioned high temperature safety problem, the size of the battery cell can be increased, which can be realized by improving the structure of the electrode terminal of the battery cell, increasing the space efficiency within the battery can, decreasing the internal resistance, and increasing the energy density. [Brief description of the drawings]

[0037] 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 facilitate understanding of the technical concepts of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters depicted in such drawings.

[0038] [Figure 1] FIG. 2 is a plan view showing the structure of an electrode plate used in a conventional tab-less battery cell. [Diagram 2] 1A to 1C are diagrams showing a winding process of an electrode assembly included in a conventional tab-less battery cell. [Diagram 3] 3A to 3C are diagrams showing a process in which a current collecting plate is welded to a folded surface of an uncoated portion in the electrode assembly of FIG. 2. [Figure 4]1 is a cross-sectional view of a conventional tab-less battery cell cut in the longitudinal direction Y. FIG. [Diagram 5] FIG. 2 illustrates an electrode assembly in an unwound state according to an embodiment of the present invention. [Figure 6] FIG. 6 is a front view showing the electrode assembly according to FIG. [Figure 7] FIG. 6 is a plan view showing the electrode assembly according to FIG. 5. [Figure 8] FIG. 4 is a cross-sectional view showing a rivet configuration of an electrode terminal according to an embodiment of the present invention. [Figure 9] 9 is an enlarged cross-sectional view of a portion circled with a dotted line in FIG. 8. [Figure 10] 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 11] 2 is a plan view illustrating an example of a structure of an electrode plate according to a preferred embodiment of the present invention; FIG. [Figure 12] 2 is a cross-sectional view taken along a longitudinal direction Y of an electrode assembly in which a segmented structure of an 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 13] 4 is a cross-sectional view of an electrode assembly in which a non-coating portion is folded, taken along a longitudinal direction Y, according to an embodiment of the present invention. [Figure 14] 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 15] 1 is a diagram showing a schematic configuration of a vehicle including a battery pack according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical ideas of the present invention, based on the principle that the inventor can appropriately define the concepts of terms in order to best describe the invention.

[0040] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0041] Throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, not excluding other elements, unless specifically stated to the contrary.

[0042] In addition, the term "part" in this specification means a unit that processes at least one function, operation, etc. In addition, in the entire specification, "from A to B" means A or more and B or less, and means a numerical range including both A and B. Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0043] In order to facilitate understanding of the present invention, the accompanying drawings may be illustrated with exaggerated dimensions of some components rather than with actual dimensions, and the same reference numerals may be used to refer to the same components in different embodiments.

[0044] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0045] One embodiment of the present invention provides an electrode assembly in which a first electrode 2, separators 4 and 5, and a second electrode 3 are stacked and wound up, at least one of the first electrode 2 and the second electrode 3 includes a current collector 91 and an electrode active material layer 92 provided on the current collector, and the first electrode is provided on the electrode active material layer 92, and includes a fixing portion 7 provided on an edge 6 closest to the center of the electrode assembly when wound, and fixed to at least a portion of the separators 4 and 5.

[0046] The electrode active material layer 92 may be provided by coating on a current collector 91 of the electrode.

[0047] According to one example, the first electrode 2 may be provided larger than the second electrode 3, and the first electrode active material layer may be provided larger than the second electrode active material layer.

[0048] The fixing portion 7 may be provided on the electrode active material layer 92, and may be provided on the edge portion 6 closest to the winding center of the electrode assembly.

[0049] If the fixing part 7 is provided in a plain area not including the electrode active material layer, the cost competitiveness may be reduced due to the need to provide the plain area. However, since the fixing part 7 is provided in the electrode active material layer 92, the cost competitiveness is high and the shrinkage of the separator due to high temperatures can be prevented, which is advantageous.

[0050] The winding center refers to a position where winding of the stacked electrodes and the separator begins, and may be provided in a core region of the electrode assembly.

[0051] The edge 6 closest to the winding center means the part provided on the winding center 0 side of the two edges provided in the winding axis direction of the electrode.

[0052] The separator 4 may be provided between the first electrode 2 and the second electrode 3, and at least a portion of the separator 4 may be fixed to the fixing part 7. By fixing the separator 4 to the fixing part 7, it is possible to prevent the separator from shrinking due to high temperatures even in an electrode assembly that does not have a structure in which a cathode tab is attached.

[0053] In addition, by solving the high temperature safety problem, the size of the battery cell can be increased, which can be realized by improving the structure of the electrode terminal of the battery cell to increase the space efficiency within the battery can, reduce the internal resistance, and increase the energy density.

[0054] FIG. 5 is a diagram illustrating an unwound state 1 of an electrode assembly according to an embodiment of the present invention.

[0055] 5, an electrode assembly according to an embodiment of the present invention includes a first electrode 2, separators 4, 5, and a second electrode 3 stacked and in an unwound state 1, and the separators 4, 5 may include a first separator 4 and a second separator 5. Preferably, the first electrode 2 is larger than the second electrode 3, and the separators 4, 5 should be larger than the first electrode 2 and the second electrode 3. Here, larger size means that the separators can be provided longer in the longitudinal direction of the electrode assembly perpendicular to the winding axis.

[0056] The fixing portion 7 is provided in the active material layer of the first electrode, at the edge 6 closest to the center of the wound electrode assembly, and is fixed to at least a part of the separators 4, 5.

[0057] 6 and 7 are front and plan views, respectively, showing the electrode assembly according to FIG.

[0058] 6 and 7, an example of an unwound state 1 of an electrode assembly according to an embodiment of the present invention is shown, in which the fixing portion 7 is provided at an edge portion 6 of the active material layer in the first electrode 2 that is closest to the winding center of the electrode assembly, and the fixing portion 7 is fixed to a portion of the separators 4 and 5 so as not to be separated.

[0059] According to one embodiment, the electrode assembly includes uncoated portions (first electrode uncoated portion 8, second electrode uncoated portion 9) that do not have the active material layer, and the uncoated portions 8, 9 may be provided on an edge portion of the current collector provided on one end side of the winding shaft of the electrode assembly.

[0060] The uncoated portions 8, 9 may be provided on one end of the winding shaft of the electrode assembly in the first electrode 2 and the second electrode 3. According to one example, the uncoated portions 8, 9 may extend and be exposed from both ends of the electrode assembly. Preferably, the uncoated portion 8 of the first electrode and the uncoated portion 9 of the second electrode may be provided in opposite directions on both ends of the electrode assembly (see FIG. 7).

[0061] The uncoated portions 8 and 9 extend from both ends of the electrode assembly and are exposed to be electrically connected to the current collecting plates 78 and 79, thereby reducing the internal resistance and increasing the energy density. Furthermore, even if the electrode assembly does not have a structure in which tabs or leads are connected, the shrinkage of the separator due to high temperatures can be prevented.

[0062] The electrode active material layer 92 may be provided in an area excluding the uncoated portions 8 and 9. According to one example, the electrode active material layer 92 may be provided in an area excluding the edge portion where the uncoated portion is provided at the edge of the current collector. In addition, the electrode active material layer 92 may not extend or be exposed from both side edges of the electrode assembly, and the first electrode active material layer and the second electrode active material layer may not overlap each other with the separator 4 interposed therebetween.

[0063] According to one embodiment, the separation membranes 4, 5 include a first separation membrane 4 provided between the first electrode 2 and the second electrode 3 and a second separation membrane 5 provided on the opposite side of the first electrode opposite the side facing the first separation membrane, and at least one of the first separation membrane 4 and the second separation membrane 5 is fixed to the fixing portion 7.

[0064] According to one example, the first separation membrane 4 may be provided between the first electrode 2 and the second electrode 3 and fixed to the fixing portion 7, and the second separation membrane 5 may be provided on the opposite side of the first electrode 2 from the side facing the first separation membrane 4 and fixed to the fixing portion 7.

[0065] The fixing portion 7 may be provided on one side of the first electrode 2 and fixed to the first separation membrane 4, or may be provided on the other side of the first electrode 2 and fixed to the second separation membrane 5. Preferably, the fixing portion 7 may be provided on both one and the other sides of the first electrode 2 and fixed to the first separation membrane 4 and the second separation membrane 5.

[0066] By providing fixing parts 7 to be fixed to the separators 4 and 5 in the electrodes of the electrode assembly, it is possible to prevent the separator from shrinking due to high temperatures.

[0067] In addition, since the fixing part 7 provided on one side and / or the other side of the first electrode 2 is fixed to the first separator 2 and the second separator 3, the size of the battery cell can be increased, and even in such a battery cell, the shrinkage phenomenon of the separator due to high temperature can be effectively prevented.

[0068] According to one embodiment, the fixing portion 7 does not overlap the second electrode 3 in the unwound state 1 of the electrode assembly.

[0069] The unwound state 1 of the electrode assembly is a state in which a first electrode 2, a separator 4, and a second electrode 3 are stacked, and the first electrode 2 may be larger than the second electrode 3. The first electrode 2 being larger than the second electrode 3 means that the first electrode 2 is longer than the second electrode 3 in the longitudinal direction Y of the electrode assembly perpendicular to the winding axis. In this case, the separator 4 must be longer than the first electrode 2 and the second electrode 3.

[0070] The fixing portion 7 may be provided at the edge 6 closest to the winding center of the electrode assembly, and referring to FIG. 6, the fixing portion 7 may be provided so as not to overlap with the second electrode 3 when the electrode assemblies are stacked.

[0071] Since the fixing portion 7 does not overlap the second electrode 3, damage to the separator can be prevented even when the electrode assembly is filled, and a decrease in the life span of the battery can be prevented.

[0072] According to an embodiment, the width 7W of the fixing part may be 12 mm or less, 11.5 mm or less, 11 mm or less, 10.5 mm or less, or 10 mm or less. The width 7W of the fixing part may be 2 mm or more, 3 mm or more, or 4 mm or more. The width 7W of the fixing part is fixed to the separators 4 and 5 within the above range, and the shrinkage of the separators can be prevented even at high temperatures. According to an example, the width 7W of the fixing part may be 15% to 65% of the outer peripheral surface of the winding core 80. The width 7W of the fixing part may be 15% or more, 20% or more, 25% or more, 30% or more, or 35% or more of the outer peripheral surface of the winding core 80. The width 7W of the fixing part may be 65% or less, 60% or less, 55% or less, 50% or less, or 45% or less of the outer peripheral surface of the winding core 80.

[0073] The outer circumferential surface of the winding core 80 can be set differently depending on the size of the battery, and thus the width 7W of the fixing portion is fixed to the separators 4 and 5 within the above range, thereby preventing the separator from shrinking at high temperatures.

[0074] The width 7W of the fixing part refers to the length of the portion of the electrode assembly in the unwound state 1 that does not overlap with the second electrode 3. The fixing part 7 may be fixed to the separators 4 and 5 within the range of the width 7W of the fixing part, thereby preventing the separator from shrinking due to high temperatures.

[0075] According to one example, the first electrode 2, the separation membranes 4 and 5, and the second electrode 3 may not be fixed in the portion other than the fixing portion 7 (see FIG. 6). This makes it possible to suppress the occurrence of folds and wrinkles during winding, and facilitates winding.

[0076] The first electrode 2 may be a cathode and the second electrode 3 may be an anode. According to one embodiment, the fixing portion 7 may be a laminate tape. The laminate tape may be a tape having an adhesive layer capable of lamination on at least one side, or may be a tape having adhesive layers capable of lamination on both sides.

[0077] The term "laminate" as used herein refers to a material that has adhesive strength at high temperatures, and means that the adhesive layer of the laminate tape is smoothed by applying heat to the adhesive layer to thereby maintain adhesive strength.

[0078] The laminate tape may be fixed to at least a portion of the separation membranes 4 and 5 .

[0079] The fixing part 7 is not limited in size, shape, or type as long as it can be fixed to the separation membrane, and may be, for example, a double-sided tape. According to one example, the double-sided tape may have adhesive strength on both sides and may be adhered to at least a part of the separation membrane for fixing.

[0080] According to one embodiment, the thermal decomposition temperature of the laminate tape may be 180° C. or more, 190° C. or more, 200° C. or more, 210° C. or more, 220° C. or more, 230° C. or more, or 240° C. or more. The thermal decomposition temperature of the laminate tape may be 320° C. or less, 310° C. or less, 300° C. or less, 290° C. or less, 280° C. or less, or 270° C. or less.

[0081] The thermal decomposition temperature of the laminate tape can be set differently depending on the type of substrate. When the above range is satisfied, the thermal decomposition temperature of the laminate tape is higher than the melting point of the separator, and the laminate tape can be fixed to the separator before the separator melts, thereby preventing the separator from shrinking.

[0082] According to one embodiment, the adhesive strength of the laminate tape at room temperature may be 20gf / 100mm to 40gf / 100mm, 23gf / 100mm to 37gf / 100mm, or 25gf / 100mm to 35gf / 100mm. For example, the adhesive strength of the laminate tape at room temperature may be 20gf / 100mm or more, 23gf / 100mm or more, 25gf / 100mm or more, 27gf / 100mm or more, or 29gf / 100mm or more. The adhesive strength of the laminate tape at room temperature may be 40gf / 100mm or less, 37gf / 100mm or less, 35gf / 100mm or less, 33gf / 100mm or less, or 31gf / 100mm or less. When the above range is satisfied, the laminate tape is fixed to the separators 4 and 5, and the separators can be prevented from shrinking due to high temperatures.

[0083] According to one example, the laminate tape has adhesive strength at a certain temperature or higher. Having adhesive strength at a certain temperature or higher means that the adhesive layer of the laminate tape is heated to smooth it and has adhesive strength, and the adhesive strength may be adjusted in consideration of the processability of the electrode. In this case, the laminate tape may have adhesive strength higher than that at room temperature, and is fixed to the separators 4 and 5, so that the shrinkage of the separators can be prevented even at high temperatures.

[0084] The laminate tape may have adhesive strength at about 40° C. or more, 45° C. or more, 50° C. or more, 55° C. or more, 60° C. or more, or 65° C. or more. According to one example, the laminate tape may have adhesive strength preferably at about 50° C. or more, more preferably at 60° C. or more. When this range is satisfied, the adhesive strength of the laminate tape can be exerted, which is advantageous because it allows the temperature range in which the fixing portion 7 is fixed to the separators 4 and 5 in the processing of the battery cell to be set.

[0085] According to one embodiment, the change rate of adhesive strength of the laminate tape may satisfy the following formula 1. [Formula 1] 0.8≦[X1 / X2]×100(%)≦1.2 In the above formula 1, X1 is the adhesive strength of the laminate tape when left at 23°C for 20 minutes, and X2 is the adhesive strength of the laminate tape when left at 23°C for 20 minutes and then stored at 65°C for 20 minutes.

[0086] The X1 may be the adhesive strength of the laminate tape when left for 20 minutes at 23° C., or may be the adhesive strength of the laminate tape at room temperature. The X2 may be the adhesive strength of the laminate tape when left for 20 minutes at 23° C. and then stored for 20 minutes at 65° C., or may be the adhesive strength of the laminate tape after lamination.

[0087] The lamination refers to applying heat to the adhesive layer of the laminate tape to make it smooth and adhesive, and can be carried out through a lamination process.

[0088] Within this range, the laminating tape can maintain its adhesive strength before and after lamination, and can be fixed to the separators 4 and 5 to prevent the separators from shrinking due to high temperatures.

[0089] Regarding the method for measuring the adhesive strength of the laminate tape, the X1 means the adhesive strength of the laminate tape when left at 23°C for 20 minutes. The adhesive layer of the laminate tape is pressed against a SUS304 substrate by rolling a 2 kg rubber roller back and forth once, and then left at 23°C for 20 minutes. The adhesive strength can be measured by peeling the colored polyimide backplate film at an angle of 180° and at a peeling speed of 300 mm / min using a Texture analyzer (Stable Micro Systems).

[0090] The X2 refers to the adhesive strength of the laminate tape when left at 23°C for 20 minutes and then stored at 65°C for 20 minutes. The adhesive layer of the laminate tape was pressed against a SUS304 substrate by rolling it back and forth once with a 2 kg rubber roller, left at 23°C for 20 minutes, and then stored at 65°C for 20 minutes. The colored polyimide backplate film was then peeled off at an angle of 180° at a peeling speed of 300 mm / min using a Texture analyzer (Stable Micro Systems).

[0091] According to one embodiment, the fixing portion 7 is fixed to at least a part of the separation membrane at two points provided on edge sides facing each other in the winding axis direction of the electrode assembly and at one point provided between the two points. The two points and the one point of the fixing portion 7 may be the minimum parts for fixing to the separation membranes 4 and 5, and there are no limitations on the size and shape of the fixing portion 7 as long as it is fixed to the separation membrane.

[0092] In one example, the three points including the two points and the one point are provided within the fixing portion 7 and may include three or more separated parts or may consist of an area without being separated, and are not particularly limited in position or area as long as they are fixed to the separation membranes 4 and 5.

[0093] According to one embodiment, the fixing part 7 may be fixed to the separator over at least 40%, at least 50%, or at least 60% of the length of the electrode assembly in the winding axis direction. Within this range, the fixing part 7 may be fixed to the separators 4 and 5 without being separated therefrom, and shrinkage of the separator at high temperatures may be prevented.

[0094] The length of the electrode assembly in the winding axis direction may be the length of an edge in the winding axis direction or the length between opposing edges of the electrode assembly in the winding axis direction. In addition, 40% or more of the length of the electrode assembly in the winding axis direction may be a continuous length range or a discontinuous length range.

[0095] One embodiment of the present invention provides a battery cell 70 including an electrode assembly 71 according to an embodiment of the present invention, a battery can 51 having an opening on one side for accommodating the electrode assembly, an electrode terminal 50 riveted through a through hole formed in the bottom of the battery can, a gasket 54 provided between the electrode terminal and the outer diameter of the through hole, and a sealing body 74 for sealing the opening of the battery can. As an example, the electrode terminal riveted to the bottom of the battery can may have a rivet structure.

[0096] The battery cell 70 includes the electrode assembly 71 according to an embodiment of the present invention, so that the contraction of a separator due to high temperature can be prevented, and the high temperature safety problem can be solved, and the size of the battery cell 70 can be increased.

[0097] In addition, by improving the structure of the electrode terminal of the battery cell 70, the space efficiency within the battery can 51 can be increased, the internal resistance can be reduced, and the energy density can be increased, thereby realizing an increase in the size of the battery cell 70.

[0098] According to one embodiment, the first electrode 2 is electrically connected to the battery can 51, the second electrode 3 is electrically connected to the electrode terminal 50, and the sealing body 74 can be insulated from the battery can 51.

[0099] FIG. 8 is a cross-sectional view showing the rivet structure of an electrode terminal 50 according to an embodiment of the present invention, and FIG. 9 is an enlarged cross-sectional view of the portion circled with a dotted line.

[0100] 8 and 9, the rivet structure of the electrode terminal 50 according to the embodiment may include a cylindrical battery can 51 having one 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.

[0101] 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.

[0102] The electrode terminal 50 is made of a conductive metal material. In one example, the electrode terminal 50 may be made of aluminum, but the present invention is not limited thereto.

[0103] The gasket 54 may be made of insulating and elastic polymer resin. In one example, the gasket 54 may be made of polypropylene, polybutylene terephthalate, polyethylene fluoride, etc., but the present invention is not limited thereto.

[0104] 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 along the external surface 52a, 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, and a flat portion 50d provided on the inside of the internal flange portion 50c.

[0105] 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.

[0106] 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 magnitude 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. As an 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.

[0107] 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. As an example, the asymmetric groove may be substantially V-shaped. The asymmetric groove may include a side wall 55a of the flat portion 50d and an inclined surface 55b of the inner flange portion 50c connected to an end of the side wall 55a. The side wall 55a may be substantially perpendicular to the inner surface 52b of the bottom portion 52 of the battery can 51. "Perpendicular" means that it is 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 provided in the through hole 53 of the battery can 51 by a crimping method.

[0108] Preferably, the thickness of the inner flange portion 50 c may decrease as it moves away from the body portion 50 a of the electrode terminal 50 .

[0109] According to another 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.

[0110] 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 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 may be relatively small. Preferably, a point of minimum thickness may be present in the gasket region 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 may include an opposing surface 57 facing the inner flange portion 50c.

[0111] 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.

[0112] 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.

[0113] In another aspect, the height H1 of the flat portion 50d with respect 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 inner gasket portion 54b.

[0114] Furthermore, the height H1 of the flat portion 50d based on 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 inner flange portion 50c.

[0115] When the height parameters H1, H2, and H3 satisfy the above conditions, the inner flange portion 50c and the inner gasket portion 54b can be prevented from interfering with other components.

[0116] In another aspect, a radius R1 from the center of the body portion 50a of the electrode terminal 50 to the edge of the external flange portion 50b may be 10% to 60% of a radius R2 of the bottom portion 52 of the battery can 51 as a reference.

[0117] If R1 is small, there is insufficient welding space when welding an electrical wiring component (bus bar) to the electrode terminal 50. If R1 is large, there is a decrease in 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.

[0118] By adjusting the ratio R1 / R2 between 10% and 60%, a suitable welding space between the electrode terminal 50 and the outer surface of the bottom 52 of the battery can 51 can be secured.

[0119] 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.

[0120] If R3 is small, there may be insufficient welding space when welding the current collecting plate (see 79 in FIG. 10) to the flat portion 50d of the electrode terminal 50, reducing the welding area of ​​the electrode terminal 50 and increasing the contact resistance. Also, R3 must be smaller than R1, and if R3 is large, the thickness of the inner flange portion 50c becomes thin, weakening the force with which the inner flange portion 50c presses the gasket 54, which may reduce the sealing ability of the gasket 54.

[0121] 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. 10), which not only facilitates the welding process but also reduces the contact resistance in the welded area and prevents a decrease in the sealing ability of the gasket 54.

[0122] According to one embodiment of the present invention, the rivet structure of the electrode terminal 50 may be formed using a crimping tool 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 it is riveted.

[0123] 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.

[0124] Next, the crimping tool is moved downward to pressure-form the upper part of the preform, thereby transforming the preform into a riveted electrode terminal 50.

[0125] While the preform is pressurized by the crimping tool, the outer gasket portion 54a interposed between the outer flange portion 50b and the outer surface 52a of the bottom portion 52 of the battery can 51 is elastically compressed, thereby reducing its thickness. Also, 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, thereby reducing its thickness more than other regions. In particular, the region where the thickness of the inner gasket portion 54b is reduced in a concentrated manner is the portion indicated by the dotted circle in FIG. 9. This significantly improves the sealing and hermeticity between the riveted electrode terminal 50 and the battery can 51.

[0126] Preferably, the gasket 54 is compressed sufficiently to ensure the desired sealing strength without being physically damaged during the process in which the preform is riveted.

[0127] In one example, when gasket 54 is made of polybutylene terephthalate, gasket 54 preferably has a compressibility of 50% or more at the point where it is compressed to its minimum thickness. Compressibility is the ratio of the change in thickness before and after compression to the thickness before compression.

[0128] In another example, when gasket 54 is made of polyfluoroethylene, gasket 54 preferably has a compressibility of 60% or greater at the point where it is compressed to its minimum thickness.

[0129] In yet another example, when gasket 54 is made of polypropylene, gasket 54 preferably has a compressibility of 60% or greater at the point where it is compressed to its minimum thickness.

[0130] Preferably, the crimping jig is moved up and down at least two times to perform the pressure forming of the upper part of the preform in stages. That is, the preform can be deformed multiple times by pressure forming in stages. At this time, the pressure applied to the crimping jig can be increased in stages. In this way, the stress applied to the preform can be dispersed multiple times, thereby preventing the gasket 54 from being damaged during the crimping process. In particular, when a portion of the inner gasket portion 54b interposed between the inner edge 56 of the through hole 53 and the preform is compressed intensively by the inner flange portion 50c, damage to the gasket is minimized.

[0131] After the pressure forming of the preform using the crimping jig is completed, the crimping jig is separated from the battery can 51, whereby the rivet structure of the electrode terminal 50 according to the embodiment of the present invention is obtained, as shown in FIG.

[0132] According to the above-described embodiment, the crimping jig pressurizes and forms the upper part of the preform through up and down movement inside the battery can 51. In some cases, a rotary rotating jig used in the prior art for pressurizing the preform may be used.

[0133] 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 is also long. In this case, the rotation radius of the end of the rotary rotation jig becomes large, and pressure forming of the preform may not be performed properly. Therefore, pressure forming using a crimping jig is more effective than a method using a rotary rotation jig.

[0134] The rivet configuration of the electrode terminal 50 according to the embodiment of the present invention described above is applicable to a battery cell.

[0135] 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.

[0136] 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 height (H) to diameter (Φ)) of greater than about 0.4.

[0137] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. The cylindrical battery cell according to an embodiment of the present invention may be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, a 46800 cell, or a 46900 cell. In the numerical value indicating the form factor, the first two digits indicate the diameter of the cell, the next two digits indicate the height of the cell, and the last digit 0 indicates that the cross section of the cell is circular.

[0138] A battery cell according to one embodiment of the present invention may be a generally cylindrical battery cell having a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0139] Another embodiment of the battery cell may be a generally cylindrical cell having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0140] In another embodiment, the battery cell may be a cylindrical battery cell that is substantially cylindrical, having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0141] In yet another embodiment, the battery cell may be a generally cylindrical cell having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0142] In yet another embodiment, the battery cell may be a generally cylindrical cell having a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0143] In yet another embodiment, the battery cell may be a generally cylindrical cell having a diameter of about 46 mm, a height of about 90 mm, and a form factor ratio of 0.511.

[0144] Conventionally, battery cells with a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, 18650 cells, 21700 cells, etc. have been used. In the case of an 18650 cell, its diameter is about 18 mm, its height is about 65 mm, and its form factor ratio is 0.277. In the case of a 21700 cell, its diameter is about 21 mm, its height is about 70 mm, and its form factor ratio is 0.300.

[0145] FIG. 10 is a cross-sectional view of a battery cell 70 according to an embodiment of the present invention taken along a longitudinal direction Y.

[0146] Referring to FIG. 10, 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 the electrode assembly 71 includes uncoated portions 72 of the first electrode plate and uncoated portions 73 of the second electrode plate that extend and are exposed from both side ends.

[0147] In an embodiment, the first electrode plate may be a cathode plate and the second electrode plate may be an anode plate, or vice versa.

[0148] The method of winding the electrode assembly 71 is substantially the same as the method of winding an electrode assembly used in manufacturing a tab-less battery cell according to the prior art described with reference to FIG.

[0149] When illustrating 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 are omitted from the illustration.

[0150] 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.

[0151] Preferably, one side (lower part) of the battery can 51 is open. In addition, the bottom part 52 of the battery can 51 has a structure in which the electrode terminal 50 is riveted to the through hole 53 through a crimping process.

[0152] 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 .

[0153] The battery cell 70 may also include a sealing body 74 that seals the open end of the battery can 51 to be insulated from the battery can 51. Preferably, the sealing body 74 may include a non-polarized cap plate 74a and a sealing gasket 74b interposed between an edge of the cap plate 74a and the open end of the battery can 51.

[0154] The cap plate 74a may be made of a conductive metal material such as aluminum, steel, nickel, etc. Also, the sealing gasket 74b may be made of insulating and elastic polypropylene, polybutylene terephthalate, polyethylene fluoride, etc. However, the present invention is not limited by the materials of the cap plate 74a and the sealing gasket 74b.

[0155] The cap plate 74a may include vent notches 77 that rupture when pressure inside the battery can 51 exceeds a threshold value. 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, linear pattern, or other pattern on the surface of the cap plate 74a.

[0156] The battery can 51 may include a crimping portion 75 that extends and bends inside the battery can 51 to wrap around and secure the edge of the cap plate 74a together with the sealing gasket 74b to secure the sealing body 74.

[0157] The battery can 51 may also include a beading portion 76 pressed into the inside of the battery can 51 in a region adjacent the open end. The beading portion 76 supports the edge of the seal 74, particularly the outer peripheral surface of the sealing gasket 74b, when the seal 74 is secured by the crimping portion 75.

[0158] 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. Alternatively, at least a portion 78a of the end 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.

[0159] 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.

[0160] Preferably, when the second current collecting plate 79 is welded, the 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. Also, 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, so that strong pressure is applied to the welding area to improve the quality of the welding. Also, since the flat portion 50d of the electrode terminal 50 has a wide area, a wide welding area can be secured. 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 the current density per unit area can be reduced in the cross section in the direction of current flow, so that the amount of heat generated in the current path can be reduced compared to the conventional method.

[0161] The flat portion 50d of the electrode terminal 50 may 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 may be adjusted differently depending on the welding method, and is preferably 2 mm or more for the sake of weld strength and ease of the welding process.

[0162] In one example, when the flat portion 50d and the second current collecting plate 79 are welded by a laser to form a continuous or discontinuous line in the form of a circular pattern, the diameter of the flat portion 50d is preferably 4 mm or more. If the diameter of the flat portion 50d satisfies this condition, it is possible to ensure the welding strength, 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.

[0163] 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. When 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.

[0164] 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 52a 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' may include a welding hole 80a that exposes the flat portion 50d of the electrode terminal 50 to the second current collecting plate 79 side, and may cover the surface of the second current collecting plate 79 and the edge of one side (upper portion) of the electrode assembly 71.

[0165] Preferably, the uncoated portions 72, 73 of the first electrode plate and / or the second electrode plate may be folded from the outer periphery side of the electrode assembly 71 toward the core side to form folded surfaces at the upper and lower parts of the electrode assembly 71. Also, the first current collecting plate 78 may be welded to the folded surface formed by folding the uncoated portion 72 of the first electrode plate, and the second current collecting plate 79 may be welded to the folded surface formed by folding the uncoated portion 73 of the second electrode plate.

[0166] In order to relieve stress that occurs when the plain portions 72, 73 are folded, the first electrode plate and / or the second electrode plate may have an improved structure that is different from a conventional electrode plate (see FIG. 4).

[0167] FIG. 11 is a plan view illustrating an example of the structure of an electrode plate 90 according to a preferred embodiment of the present invention.

[0168] Referring to FIG. 11, an electrode plate 90 includes a sheet-like current collector 91 made of a foil of a conductive material, an active material layer 92 formed on at least one surface of the current collector 91, and a plain portion 93 at the end of the long side of the current collector 91 where no active material is coated.

[0169] Preferably, the plain portion 93 may include a plurality of segment pieces 93a that are notched. The plurality of segment pieces 93a may be formed into a plurality of groups, and the segment pieces 93a belonging to 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 belonging to each group may be increased or decreased from that shown in the figure. The segment pieces 93a may be trapezoidal, or may be modified into a rectangle, a parallelogram, a semicircle, or a semi-ellipse.

[0170] Preferably, the height of the segment pieces 93a may increase stepwise from the core side to the outer periphery side. Also, the core-side uncoated area 93' adjacent to the core side may not include the segment pieces 93a, and the height of the core-side uncoated area 93' may be smaller than the height of the other uncoated areas.

[0171] 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 facing the separator, and serves to structurally support the folding of the segment pieces 93a. For this reason, when the electrode plate 90 is wound into an electrode assembly, it is preferable that at least a portion of the insulating coating layer 94 is exposed to the outside through the separator.

[0172] FIG. 12 is a cross-sectional view taken along a 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 a first electrode plate and a second electrode plate.

[0173] 12, the electrode assembly 100 can be manufactured by the winding method described with reference to FIG. 2. For ease of explanation, the protruding structure of the uncoated portions 72, 73 extending outward from the separator is illustrated in detail, and the winding structure of the first electrode plate, the second electrode plate, and the separator is not illustrated. 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.

[0174] The pattern in which the height of the uncoated portions 72, 73 varies is illustrated diagrammatically. That is, the height of the uncoated portions 72, 73 may vary irregularly depending on where the cross section is cut. As an example, when a side portion of the trapezoidal segment 93a is cut, the height of the uncoated portions in the cross section will be lower than the height of the segment 93a. Therefore, it should be understood that the height of the uncoated portions 72, 73 shown in the cross-sectional view of the electrode assembly 100 corresponds to the average height of the uncoated portions included in each winding pattern.

[0175] The uncoated portions 72, 73 may be folded from the outer periphery side of the electrode assembly 100 to the core side as shown in FIG. 13. In FIG. 12, the folded portion 101 is indicated by a dotted box. When the uncoated portions 72, 73 are folded, the radially adjacent segments overlap each other multiple times to form folded surfaces 102 at the top and bottom of the electrode assembly 100. At this time, the uncoated portion on the core side (93' in FIG. 11) is not folded due to its low height, and the height h of the segment folded from the innermost side is equal to or smaller than the radial length r of the winding area formed by the uncoated portion 93' on the core side 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, welding between the electrode terminal 50 and the second current collecting plate 79 can be easily performed.

[0176] 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 polarity. Instead, since the first current collecting plate 78 is connected to the side wall of the battery can 51, the outer surface 52a of the bottom 52 of the battery can 51 has the opposite polarity to the electrode terminal 50. Therefore, when it is desired to connect multiple cells in series and / or in 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 can increase the number of cells that can be mounted in the same space, thereby improving energy density.

[0177] 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 limitations.

[0178] In one example, the positive electrode active material has the general formula A[A x M y ]O 2+z (A includes at least one of Li, Na, and K; M includes at least one of 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; x, y, z, and the stoichiometric coefficients of the components included in M ​​are selected such that the compound remains electrically neutral).

[0179] 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 O 2 .(1-x)Li 2 M 2 O 3 (M 1 contains at least one element having an average oxidation state of 3; M 2 contains at least one element having an average oxidation state of 4; 0≦x≦1).

[0180] In still other examples, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 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; <a≦2、0≦x≦1、0≦y<1、0≦z<1;a、x、y、z、M 1 , M 2 and M. 3 The stoichiometric coefficients of the components included in are chosen so that the compound remains electroneutral), or Li 3 M 2 (PO 4 ) 3 [M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0181] Preferably, the positive electrode active material may include primary particles and / or secondary particles formed by agglomeration of the primary particles.

[0182] 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, tin or a tin compound, etc. 2 , SnO 2 Metal oxides such as the following can also be used as the negative electrode active material. As the carbon material, either low crystalline carbon or high crystalline carbon may be used.

[0183] The separation membrane may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., which may be used alone or in combination. As another example, the separation membrane may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of a high melting point glass fiber, a polyethylene terephthalate fiber, etc.

[0184] At least one surface of the separation membrane may include a coating layer of inorganic particles.

[0185] In addition, 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 to a binder so that there is an interstitial volume between adjacent particles.

[0186] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles may be Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg 3 Nb 2 / 3 )O 3 -PbTiO 3 (PMN-PT), BaTiO 3 , hafnia (HfO 2 ), SrTiO 3 , TiO 2 , Al 2 O 3 , ZrO 2 , SnO 2 , CEO 2 , MgO, CaO, ZnO and Y 2 O 3 The composition may include at least one substance selected from the group consisting of:

[0187] The electrolyte is A +B - The salt may have the structure: + Li + , Na + , K + or combinations thereof. - F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , B.F. 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , P.F. 6 - , SbF 6 - , AsF 6 - , B.F. 2 C 2 O 4 - , B.C. 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , C.F. 3 SO 3 - , C 4 F 9 SO 3 - , C.F. 3 CF 2 SO 3- , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , C.F. 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - ,(SCIENCE FICTION 5 ) 3 C - , (CF 3 SO 2 ) 3 C - , C.F. 3 (CF 2 ) 7 SO 3 - , C.F. 3 CO 2 - , C.H. 3 CO 2 - , SCN - and (CF 3 CF 2 SO 2 ) 2 N - The anion comprises one or more anions selected from the group consisting of:

[0188] 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 (ETM), gamma butyrolactone, or a mixture thereof.

[0189] Yet another embodiment of the present invention provides a battery pack including at least one battery cell as described above.

[0190] The cylindrical battery cells according to the above-described embodiments may be used to manufacture a battery pack.

[0191] FIG. 14 is a diagram illustrating a schematic configuration of a battery pack according to an embodiment of the present invention.

[0192] 14, 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 convenience 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 illustration.

[0193] Yet another embodiment of the present invention provides a vehicle including at least one battery pack as described above.

[0194] 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 include a four-wheeled vehicle or a two-wheeled vehicle.

[0195] FIG. 15 is a diagram for explaining an automobile including the battery pack 200 of FIG.

[0196] 15, an automobile V according to an embodiment of the present invention includes a battery pack 200 according to an embodiment of the present invention. The automobile V is operated by receiving power from the battery pack 200 according to an embodiment of the present invention.

[0197] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and it is of course possible for a person having ordinary knowledge in the technical field to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the claims described below. [Explanation of symbols]

[0198] 0... Center of winding 1. Unwound state of electrode assembly 2. First electrode 3. Second electrode 4. First separation membrane 5. Second separation membrane 6. The edge of the electrode assembly closest to the center of the winding 7...Fixed part 7W: Width of the fixed part 8: First electrode uncoated portion 9. Second electrode uncoated portion 10...Anode plate 10a: Uncoated portion of anode plate 11 Cathode plate 11a: Uncoated portion of cathode plate 12...Separation membrane 20 Current collector 21...Active material 22 Plain area 30, 31: Current collecting plate 40 ···Table-less 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 50...electrode terminal 50a Body 50b External flange part 50c... Internal flange part 50d...Flat area 51 Cylindrical battery can with one side open 51a: Inner circumferential surface of side wall of battery can 52...Bottom 52a External surface 52b ···Internal surface 53 ...Through hole 54 Gasket 54a External gasket part 54b Internal gasket part 55 Recessed portion 55a Flat side wall 55b: Inclined surface of inner flange 56 Inner edge (inner edge of through hole) 57 .... Opposing surface (opposing surface facing the internal flange portion) 70 ···Battery Cell 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 section 76 Beading section 76a Inner surface of beading portion 77 ···Bent Notch 78 First current collecting plate 78a Edge of first current collecting plate 79 Second current collecting plate 79a...Central part 80 ···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...Folded surface 200···Battery pack 201 ···Cylindrical battery cell 202 Pack Housing

Claims

1. An electrode assembly in which a first electrode, a separator, and a second electrode are stacked and wound, At least one of the first electrode and the second electrode includes a current collector and an electrode active material layer provided on the current collector, an edge portion of the current collector provided on one end side of a winding shaft of the electrode assembly includes a plain portion on which the electrode active material layer is not provided, The non-coated portion is provided on one long side along the winding direction (X), The first electrode is the electrode active material layer, and includes a fixing portion provided at an edge portion closest to a winding center of the electrode assembly and fixed to at least a portion of the separator.

2. the separation membrane includes a first separation membrane provided between the first electrode and the second electrode, and a second separation membrane provided on the opposite side of the first electrode to the surface facing the first separation membrane, The electrode assembly according to claim 1 , wherein at least one of the first separator and the second separator is fixed to the fixing portion.

3. The electrode assembly according to claim 1 , wherein the fixing portion does not overlap the second electrode when the electrode assembly is in an unwound state.

4. The electrode assembly according to claim 1 , wherein the fixing portion has a width of 12 mm or less.

5. The electrode assembly according to claim 1 , wherein the first electrode, the separator, and the second electrode are not fixed in a portion other than the fixing portion.

6. The electrode assembly of claim 1 , wherein the first electrode is a cathode and the second electrode is an anode.

7. The electrode assembly according to claim 1 , wherein the fixing portion is a laminate tape.

8. The electrode assembly according to claim 7 , wherein the laminate tape has a thermal decomposition temperature of 180° C. or higher.

9. The electrode assembly according to claim 7 , wherein the adhesive strength of the laminate tape at room temperature is 20 gf / 100 mm to 40 gf / 100 mm.

10. The electrode assembly according to claim 7 , wherein the laminate tape has adhesive strength at 40° C. or higher.

11. The electrode assembly according to claim 7 , wherein a rate of change in adhesive strength of the laminate tape satisfies the following formula 1: [Formula 1] 0.8≦[X2 / X1]×100(%)≦1.2 In the above formula 1, X1 is the adhesive strength of the laminate tape when left at 23°C for 20 minutes, and X2 is the adhesive strength of the laminate tape when left at 23°C for 20 minutes and then stored at 65°C for 20 minutes.

12. 2. The electrode assembly according to claim 1, wherein the fixing portion is fixed to at least a portion of the separation membrane at two points provided on edge sides opposing each other in a winding axis direction of the electrode assembly and at one point provided between the two points.

13. The electrode assembly according to claim 1 , wherein the fixing portion is fixed to the separator over 40% or more of a length in a winding axis direction of the electrode assembly.

14. 14. A battery cell comprising: the electrode assembly according to claim 1; a battery can having an opening on one side for accommodating the electrode assembly; an electrode terminal riveted through a through hole formed in a bottom of the battery can; a gasket provided between the electrode terminal and an outer diameter of the through hole; and a sealing body for sealing the opening of the battery can.

15. 15. The battery cell according to claim 14, wherein the first electrode is electrically connected to the battery can, the second electrode is electrically connected to the electrode terminal, and the sealing body is insulable from the battery can.

16. A battery pack comprising at least one battery cell according to claim 14.

17. 17. A motor vehicle comprising at least one battery pack according to claim 16.

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