Cylindrical battery, battery pack including the cylindrical battery, and automobile

Abstract

The present invention provides a cylindrical battery, a battery pack including the cylindrical battery, and an automobile. The cylindrical battery includes: an electrode assembly having a first electrode tab and a second electrode tab; a battery casing that houses the electrode assembly through an opening formed on one side and is electrically connected to the first electrode tab; a first current collector located inside the battery casing and including: a support portion; at least one first electrode tab connection portion; and at least one casing connection portion; a second current collector including: an edge portion disposed on the opposite side of one side of the electrode assembly; a second electrode tab connection portion extending inward from the edge portion and engaging with the second electrode tab; and a terminal connection portion disposed separately from the second electrode tab connection portion; a cover plate that seals the opening of the battery casing; and a battery terminal that engages with the terminal connection portion and is electrically connected to the second electrode tab.

Description

Technical Field

[0001] The present invention relates to a cylindrical battery and a current collector suitable for the cylindrical battery, a battery pack including such a cylindrical battery, and an automobile.

[0002] More specifically, the present invention relates to a cylindrical battery with a structure that prevents force concentration at the welded joints between components even when subjected to external impact or vibration during battery use, a current collector suitable for the cylindrical battery, a battery pack including the cylindrical battery, and an automobile.

[0003] In addition, the present invention relates to an anode for an electrochemical element with improved electrochemical properties and an electrode assembly including the above-mentioned anode. Background Technology

[0004] Secondary batteries, which are highly adaptable to various product groups and have high energy density and other electrical properties, are not only used in portable devices, but also widely used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric power sources.

[0005] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also have the advantage of producing no byproducts when using energy. Therefore, they are attracting much attention as a new energy source that is both environmentally friendly and improves energy efficiency.

[0006] Currently, widely used rechargeable batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of a single rechargeable battery cell is approximately 2.5V to 4.5V. When a higher output voltage is required, multiple batteries are connected in series to form a battery pack. Additionally, depending on the required charge / discharge capacity of the battery pack, multiple batteries are sometimes connected in parallel to form a battery pack. Therefore, the number of batteries and the electrical connection configuration within a battery pack are varied depending on the required output voltage and / or charge / discharge capacity.

[0007] On the other hand, secondary battery cells include cylindrical, square, and pouch-type batteries. In the case of a cylindrical battery, an electrode assembly in the form of a gel roll is formed by sandwiching an insulator, i.e., a separator, between the anode and cathode, and then rolling it up. This assembly, along with the electrolyte, is inserted into the battery casing to form the battery. Furthermore, strip-shaped electrode tabs are connected to the uncoated portions of both the anode and cathode, electrically connecting the electrode assembly to the exposed electrode terminals. For reference, the anode electrode terminal is a cover plate of a sealing body that seals the opening of the battery casing, and the cathode electrode terminal is the battery casing itself.

[0008] However, according to conventional cylindrical batteries with such a structure, the current is concentrated on the strip-shaped electrode tabs that are connected to the uncoated anode and / or uncoated cathode, resulting in high resistance, excessive heat generation, and poor current collection efficiency.

[0009] In small cylindrical batteries with form factors of 18650 or 21700, resistance and heat generation are not major issues. However, when the form factor is increased to make cylindrical batteries suitable for electric vehicles, more heat is generated around the electrode tabs during rapid charging, leading to the possibility of the cylindrical batteries catching fire.

[0010] To address this problem, a cylindrical battery (so-called tabless cylindrical battery) with the following structure is disclosed: an uncoated anode portion and an uncoated cathode portion are respectively provided at the upper and lower ends of a gel roll type electrode assembly, and a current collector plate is welded to such uncoated portions to improve current collection efficiency.

[0011] Below, refer to Figures 1 to 4 This section provides a more detailed explanation of the traditional cylindrical battery.

[0012] Figures 1 to 3 This is a diagram illustrating the manufacturing process of a tabless cylindrical battery. Figure 1 The structure of the electrode is shown. Figure 2 The electrode winding process is shown. Figure 3 The process of welding a current collector to the bent surface of the uncoated part is shown. Figure 4 This is a cross-sectional view of a tabless cylindrical battery cut along its length direction Y.

[0013] Reference Figures 1 to 4 The anode 500 has an anode active material portion 520 on the anode sheet 500S, and includes an anode uncoated portion 530 on one long side formed along the winding direction. The cathode 400 has a cathode active material portion 420 on the cathode sheet, and includes a cathode uncoated portion 430 on one long side formed along the winding direction. Figure 2 As shown, the electrode assembly 300 is manufactured by sequentially stacking the anode 500 and cathode 400 together with two separation membranes 600 and then winding them in one direction X. At this time, the uncoated portion 530 of the anode 500 and the uncoated portion 430 of the cathode 400 are arranged in opposite directions.

[0014] After the winding process, the uncoated portion 530 of the anode 500 and the uncoated portion 430 of the cathode 400 are bent toward the core. Then, current collectors 50 and 30 are welded onto the uncoated portions 530 and 430 respectively to form a bond.

[0015] The uncoated anode portion 530 and the uncoated cathode portion 430 are not fitted with additional electrode tabs. The current collectors 50 and 30 are connected to external electrode terminals. The current path is formed with a large cross-sectional area along the winding axis of the electrode assembly 300 (refer to the arrow), thus reducing the battery resistance. This is because resistance is inversely proportional to the cross-sectional area of ​​the current flow path.

[0016] However, if the shape factor of the cylindrical battery increases and the charging current increases during rapid charging, the heat generation problem will reappear in tabless cylindrical batteries.

[0017] Specifically, such as Figure 4 As shown, a conventional tabless cylindrical battery 1 includes a battery casing 20 and a sealing body A. The sealing body A includes a cover plate 40, a sealing gasket G1, and a connecting plate C1. The sealing gasket G1 surrounds the edge of the cover plate 40 and is fixed by a crimping portion 22. In addition, to prevent upstream and downstream movement, the electrode assembly 300 is fixed inside the battery casing 20 by a rolled edge portion 21.

[0018] Typically, the anode terminal is the cover plate 40 of the sealing body A, and the cathode terminal is the battery casing 20. Therefore, the second current collector 50, which is attached to the uncoated portion 530 of the anode 500, is electrically connected to the connecting plate C1 attached to the cover plate 40 via a strip-shaped lead L. Additionally, the first current collector 30, which is attached to the uncoated portion 430 of the cathode 400, is electrically connected to the bottom of the battery casing 20. An insulator S covers the second current collector 50 to prevent the battery casing 20 and the uncoated portion 530 of the anode 500, which have different polarities, from contacting each other and causing a short circuit.

[0019] When the second collector board 50 is connected to the connecting plate C1, a strip-shaped lead L is used. The lead L is attached independently to the second collector board 50 or formed integrally with the second collector board 50. However, the lead L is a thin strip, so its cross-sectional area is small, resulting in more heat generation when a rapid charging current flows. In addition, excessive heat generated from the lead L is transferred to the electrode assembly 300 side, causing the separation membrane 600 to shrink, which is the main cause of thermal runaway, namely internal short circuit.

[0020] Furthermore, the lead L occupies a considerable amount of space within the battery casing 20. Therefore, the cylindrical battery 1, including the lead L, has low space efficiency, thus limiting its ability to increase energy density.

[0021] Furthermore, in order to connect the conventional tabless cylindrical batteries 1 in series and / or parallel, bus components need to be connected to the cover plate 40 of the sealing body A and the bottom surface of the battery casing 20, thus reducing space efficiency. Battery packs in electric vehicles comprise hundreds of cylindrical batteries 1. Therefore, the inefficiency of the electrical wiring causes considerable trouble during the assembly of the electric vehicle and the maintenance of the battery pack. Therefore, there is a need to develop a cylindrical battery with a structure that aligns the anode and cathode terminals in the same direction to simplify the electrical connection structure of multiple cylindrical batteries.

[0022] On the other hand, conventional cylindrical batteries typically have a structure in which tabs connecting the electrode assembly and external terminals are soldered to the foil of the electrode assembly. In the case of cylindrical batteries with such a structure, the current path is limited, and the resistance of the electrode assembly itself must be very high.

[0023] Therefore, attempts were made to reduce resistance by increasing the number of tabs connecting the electrode assembly and external terminals. However, simply increasing the number of tabs in this way can reduce the resistance to the desired level while ensuring that the current path is limited.

[0024] Therefore, in order to reduce the resistance of the electrode assembly itself, it is necessary to develop a new electrode assembly structure and a current collector structure suitable for such an electrode assembly structure. In particular, the application of such a new electrode assembly and current collector structure is essential, for example, in devices such as electric vehicles that require high-power / high-capacity battery packs.

[0025] In addition, there is a need to develop a cylindrical battery with a structure that maintains a high bonding force between the current collector and the battery casing, as well as a current collector structure suitable for such a cylindrical battery.

[0026] At the same time, it is also necessary to develop a cylindrical battery that minimizes the dead corners inside the battery casing while combining the current collector and the battery casing, thereby improving the energy density of the cylindrical battery.

[0027] On the other hand, batteries have a wide variety of applications. For example, battery packs for devices like electric vehicles require large capacity and high power. Furthermore, such high-capacity, high-power battery packs may include cylindrical cells as individual battery units.

[0028] In the case of cylindrical batteries with high capacity and high power, electrode tabs are provided on both sides of the gel roll to improve current collection efficiency, and current collector plates are attached to both sides of the gel roll. By using this structure, the contact area between the electrode tabs and the current collector plates can be maximized, thereby minimizing the resistance at the connection points between components.

[0029] As mentioned above, when cylindrical batteries are used in devices such as automobiles, they are frequently subjected to external impacts and vibrations during use, which can cause damage to the joints that enable electrical connections between components. Such damage to the joints leads to product defects.

[0030] Alternatively, even if the electrical connection is not completely blocked due to damage to the joint used to achieve the electrical connection, if a part of the welded part is damaged, resulting in a reduction in the joint area between the components, the increased resistance may cause excessive heat or deformation of the components, thereby causing problems such as internal short circuits.

[0031] Therefore, there is a need to develop a cylindrical battery with a structure that can prevent force concentration at the joints between components even when subjected to external impacts and / or vibrations during use.

[0032] On the other hand, when electrodes are manufactured using anodic active materials including conventional secondary particles, particle breakage occurs. During charging and discharging, the amount of gas generated due to internal cracks increases, which poses a problem for battery safety.

[0033] To address this issue, anodic active materials with larger single-particle or similar single-particle morphologies were developed. However, when these single-particle or similar single-particle morphologies were applied to high-load electrodes and rolled, the electrode porosity did not reach the target level, leading to electrode breakage. Furthermore, the lithium secondary battery exhibited poor resistance characteristics and charge / discharge efficiency. Summary of the Invention

[0034] The problem that the invention aims to solve

[0035] The present invention was developed in view of the above-mentioned problems. The purpose of the present invention is to prevent the impact and / or vibration from concentrating on a specific part and to disperse it during the use of the battery, even if it is subjected to external impact and / or vibration, thereby preventing damage to the joints between components.

[0036] On the other hand, another objective of the present invention is that even without the addition of a current blocking component, the current blocking function can be achieved by the current collector itself, thereby quickly blocking the current when an overcurrent is generated by a short circuit or the like, thus ensuring the safety of battery use.

[0037] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art can clearly understand other problems not mentioned herein from the following description of the invention.

[0038] On the other hand, the present invention was developed in view of the above-mentioned problems, and the object of the present invention is to provide a current collector plate suitable for an electrode assembly having a low resistance structure and a cylindrical battery including the current collector plate.

[0039] In addition, the present invention aims to provide a current collector plate and a cylindrical battery including the current collector plate, which can greatly reduce the possibility of damage at the welded parts between the current collector plate and the electrode assembly and / or the welded parts between the current collector plate and the battery casing, even when subjected to vibration and impact.

[0040] In addition, an object of the present invention is to provide a current collector with a structure that improves the convenience of the welding process for electrically connecting the battery casing and the current collector when manufacturing a cylindrical battery, thereby improving productivity, and a cylindrical battery including the current collector.

[0041] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art can clearly understand other problems not mentioned herein from the following description of the invention.

[0042] On the other hand, the present invention was developed in view of the problems mentioned above. The present invention provides an electrode for an electrochemical element that exhibits excellent thermal safety as an anode active material, is suitable for single particles or similar single particles, and has high electrical conductivity and high rolling characteristics, as well as an electrode assembly for an electrochemical element including the electrode for the electrochemical element.

[0043] Another object of the present invention is to provide an electrode assembly that improves energy density by using silicon-based cathode active materials in the cathode.

[0044] In addition, the present invention aims to provide an electrode assembly with an enlarged anode active material section that eliminates concerns about lithium deposition.

[0045] Finally, the present invention provides a cylindrical lithium secondary battery that exhibits excellent thermal safety even with increased volume.

[0046] Another technical challenge of the present invention is to provide an electrode that exhibits excellent thermal safety, high conductivity and high rolling characteristics as an anode active material suitable for single-particle or similar single-particle applications, and an electrode assembly including the electrode.

[0047] Another technical challenge of the present invention is to provide an electrode assembly that improves energy density by including a silicon-based cathode active material in the cathode.

[0048] Another technical challenge of the present invention is to provide an electrode assembly that does not require concern about lithium deposition and thus increases the area of ​​the anode active material.

[0049] Another technical challenge of the present invention is to provide a cylindrical battery that exhibits excellent thermal safety even when the battery volume increases due to the increase in shape factor.

[0050] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art can clearly understand other problems not mentioned herein from the following description of the invention.

[0051] Methods for solving problems

[0052] To address the aforementioned issues, an embodiment of the present invention provides a cylindrical battery comprising: an electrode assembly having a first electrode tab and a second electrode tab; a battery casing housing the electrode assembly and electrically connected to the second electrode tab; a first current collector located within the battery casing and comprising: a support portion disposed on one side of the electrode assembly; at least one first electrode tab connection portion extending from the support portion and connected to the first electrode tab; and at least one first casing connection portion extending from the support portion and connected to the inner side of the battery casing; a second current collector comprising: an edge portion disposed on the opposite side of one side of the electrode assembly; a second electrode tab connection portion extending inward from the edge portion and connected to the second electrode tab; and a terminal connection portion disposed separately from the second electrode tab connection portion; a cover plate configured to seal an opening in the battery casing; and a battery terminal connected to the terminal connection portion and electrically connected to the second electrode tab.

[0053] The battery casing includes a rolled edge portion formed at the end adjacent to the open portion and pressed inward.

[0054] The first outer casing joint is attached to the rolled edge of the battery casing.

[0055] The aforementioned first housing assembly includes: a first contact portion which is attached to the inner side of the aforementioned battery housing; and a first connecting portion which connects the aforementioned support portion and the aforementioned contact portion.

[0056] The first contact portion has a shape in which at least a portion extends along the inner circumferential surface of the battery casing.

[0057] The aforementioned first connecting portion has at least one first curved portion that changes the direction of extension.

[0058] The first current collector also includes a second housing connection portion, which extends from the end of the first tab connection portion and is connected to the inner side of the battery housing.

[0059] The second outer casing joining portion includes: a second contact portion which is joined to the inner side of the battery casing; and a second connecting portion which connects the support portion and the contact portion.

[0060] The second contact portion has a shape in which at least a portion extends along the inner circumferential surface of the battery casing.

[0061] The aforementioned second connecting portion has at least one second curved portion that changes the direction of extension.

[0062] The aforementioned edge portion has a ring-shaped shape with the center portion empty.

[0063] The aforementioned second electrode lug and the aforementioned terminal lug are electrically connected via the aforementioned edge portion.

[0064] The aforementioned terminal joint is located at the center of the inner space of the aforementioned edge portion.

[0065] The second current collector also includes a connector that extends inward from the edge and connects to the terminal junction.

[0066] At least a portion of the aforementioned connector is narrower in width compared to the aforementioned second electrode lug joint.

[0067] The aforementioned connector has a tapered portion, the width of which gradually narrows from the inner side of the aforementioned edge portion along the direction close to the aforementioned terminal joint portion.

[0068] The aforementioned second electrode junction is formed in multiple parts.

[0069] The plurality of the aforementioned second electrode joints are arranged at the same intervals along the extension direction of the aforementioned edge portion.

[0070] The extension lengths of the various second electrode junctions mentioned above are all the same.

[0071] The aforementioned terminal joint is surrounded by a plurality of the aforementioned second electrode joints.

[0072] The aforementioned connector is located between a pair of adjacent second electrode lugs. The distance from the aforementioned connector along the extension direction of the aforementioned edge portion to either of the pair of second electrode lugs is the same as the distance from the aforementioned connector along the extension direction of the aforementioned edge portion to the other of the pair of second electrode lugs.

[0073] The aforementioned joints are formed in multiple ways.

[0074] Multiple connectors are respectively disposed between a pair of adjacent second pole lugs.

[0075] Multiple of the aforementioned connectors are arranged at equal intervals along the extension direction of the aforementioned edge portion.

[0076] The aforementioned connector has a slotted portion, which is formed in a manner that reduces the width of the aforementioned connector.

[0077] The connector has a slotted portion formed to reduce the width of the connector, and the slotted portion is positioned closer to the tapered portion than the terminal joint portion.

[0078] The aforementioned terminal joint is positioned at a location corresponding to the hole formed in the winding center portion of the aforementioned gel roll.

[0079] The aforementioned second electrode tab extends toward the closed portion located on the opposite side of the aforementioned open portion of the battery casing.

[0080] The joint portion of the second electrode tab is joined to the joint surface formed by bending the end of the second electrode tab along a direction parallel to the second current collector.

[0081] The aforementioned cover plate is not connected to the aforementioned electrode assembly and therefore does not have polarity.

[0082] The aforementioned battery terminal passes through the closed portion located on the opposite side of the aforementioned open portion of the aforementioned battery casing.

[0083] The cylindrical battery also includes an insulator sandwiched between the enclosure and the second current collector.

[0084] The battery terminals are connected to the terminal junction of the second current collector via the insulator.

[0085] The active material layer of the first electrode described above includes an anodic active material comprising single particles, similar single particles, or combinations thereof, wherein the minimum particle size D shown in the volume cumulative distribution of the anodic active material is... min The particle size D is greater than 1.0 μm, and it represents 50% of the total volume of the aforementioned anolyte active material. 50 The maximum particle size D shown in the volume cumulative distribution of the above-mentioned anolyte active material is below 5.0 μm. max The size ranges from 12μm to 17μm.

[0086] The aforementioned anodic active material exhibits a single-peak particle size distribution in the volumetric cumulative particle size distribution curve, with a particle size distribution (PSD) of 3 or less as shown by the following formula.

[0087] Formula: Particle size distribution (PSD) = (D max -D min ) / D 50

[0088] Based on the total weight of the anolyte active material included in the active material layer of the first electrode, the single particles, similar single particles, or combinations thereof are included in an amount of 95 wt% to 100 wt%.

[0089] The aforementioned anodic active material includes lithium nickel oxide, which contains more than 80 mol% Ni based on the total molar amount of the transfer metal.

[0090] The porosity of the active material layer of the first electrode is 15% to 23%, and the active material layer of the first electrode includes flake graphite in a weight ratio of 0.05 wt% to 5 wt%.

[0091] The active material layer of the first electrode also includes carbon nanotubes.

[0092] The active material layer of the second electrode includes silicon-based cathode active material and carbon-based cathode active material, and includes the silicon-based cathode active material and carbon-based cathode active material in a weight ratio of 1:99 to 20:80.

[0093] One embodiment of the battery pack of the present invention includes a cylindrical battery as described above.

[0094] An embodiment of the automobile of the present invention includes a battery pack as described above in one embodiment of the present invention.

[0095] Invention Effects

[0096] According to one aspect of the invention, even when subjected to external impacts and / or vibrations during battery use, the impacts and / or vibrations can be dispersed rather than concentrated in specific areas, thereby preventing damage at the joints between components.

[0097] On the other hand, according to another aspect of the present invention, even without the addition of a current blocking component, the current blocking function can be achieved by the current collector itself, thereby quickly blocking the current when an overcurrent occurs due to a short circuit or the like, thus ensuring the safety of battery use.

[0098] According to the present invention, resistance can be greatly reduced when electrically connecting the electrode assembly and the battery casing.

[0099] Furthermore, according to the present invention, during the use of the battery, even if it is subjected to vibration and impact, the possibility of damage to the welded joints between the current collector and the electrode assembly and / or the welded joints between the current collector and the battery casing can be greatly reduced.

[0100] Furthermore, according to the present invention, when manufacturing cylindrical batteries, the convenience of the welding process for realizing the electrical connection between the battery casing and the current collector is improved, thereby improving productivity.

[0101] According to yet another aspect of the invention, the anode includes D min The anode active material powder has a particle size of 1.0 μm or larger, thereby further improving the thermal safety of the battery. According to the inventors' research, when single-particle and / or similar single-particle anode active materials are used, the effect of calendering to suppress particle breakage and improve thermal safety varies depending on the particle size of the anode active material powder. In particular, when the anode active material powder includes particles with a particle size of less than 1.0 μm, the increased linear pressure during the calendering process leads to increased particle breakage and decreased thermal safety, making it impossible to adequately ensure thermal safety when used in large cylindrical batteries. Therefore, in this invention, a minimum particle size D is used... min By controlling the anodic active material powder to a size of 1.0 μm or larger, the improvement in thermal safety can be maximized.

[0102] According to another aspect of the invention, the anode includes a suitably adjusted D 50 D max The anolyte powder with PSD particle size distribution minimizes the increase in resistance caused by the use of single particles, thereby exhibiting excellent capacity and power characteristics.

[0103] According to another aspect of the invention, the anode comprises a single-particle-based anodic active material coated with a conductive coating or contains novel CNTs as a conductive material, thereby improving the conductivity of the electrode.

[0104] According to another aspect of the invention, the anode active material layer includes flake graphite. Therefore, when the anode active material layer is rolled, the flake graphite provides a sliding effect on the anode active material, thereby improving the rolling characteristics of the electrode and reducing the electrode porosity to the desired level. This improves the safety, initial resistance characteristics, and charge / discharge efficiency of the cylindrical battery.

[0105] According to another aspect of the invention, the cathode includes a silicon-based cathode active material with a large capacity, thereby enabling higher energy density.

[0106] According to another aspect of the invention, in the anode, there is a load reduction section where the loading of the anode active material is small, so there is no need to worry about lithium deposition and the range of the anode active material section can be increased.

[0107] According to another aspect of the present invention, compared with conventional batteries having strip-shaped electrode tabs, the internal heat generation of the battery can be effectively reduced, thereby improving the thermal safety of the battery.

[0108] However, the technical effects of the present invention are not limited to those described above, and those skilled in the art can clearly understand other effects not mentioned herein from the following description of the invention. Attached Figure Description

[0109] The accompanying drawings, which are attached to this specification, are used to illustrate preferred embodiments of the invention and, together with the embodiments described below, help to understand the technical concept of the invention. Therefore, the invention should not be interpreted in a way that limits it to the matters shown in the drawings.

[0110] Figure 1 This is a top view showing the structure of the electrodes used in conventional tabless cylindrical battery cells.

[0111] Figure 2 This diagram illustrates the winding process of electrode assemblies included in a conventional tabless cylindrical battery cell.

[0112] Figure 3 It is shown Figure 2 A diagram showing the process of welding a current collector plate to the bent surface of the uncoated part in the electrode assembly.

[0113] Figure 4 It is a cross-sectional view of a conventional tabless cylindrical battery cell cut along the length direction Y.

[0114] Figure 5 This is a cross-sectional view showing the internal structure of a cylindrical battery according to an embodiment of the present invention.

[0115] Figure 6 This is a diagram illustrating a first current collector board according to an embodiment of the present invention.

[0116] Figures 7 to 9 This is a diagram illustrating various exemplary configurations of the first connection portion of the first current collector board according to an embodiment of the present invention.

[0117] Figure 10 and Figure 11 This is a diagram showing the shape of the first connection portion at various heights of the electrode assembly.

[0118] Figure 12 This is a diagram illustrating a first current collector board according to another embodiment of the present invention.

[0119] Figure 13 This is a diagram illustrating a first current collector board according to yet another embodiment of the present invention.

[0120] Figure 14 It is shown Figure 13 A diagram illustrating the exemplary configuration of the second connection portion of the first collector plate.

[0121] Figure 15 and Figure 16A first current collector diagram of the present invention is shown, having a configuration different from that described and illustrated in the above embodiments.

[0122] Figure 17 This is a perspective view showing a cylindrical battery and a busbar for electrically connecting multiple cylindrical batteries according to an embodiment of the present invention.

[0123] Figure 18 This is a cross-sectional view showing the upper structure of a cylindrical battery according to an embodiment of the present invention.

[0124] Figure 19 This is a partial cross-sectional view of a cylindrical battery according to an embodiment of the present invention.

[0125] Figure 20 This is a diagram showing the combination of the electrode assembly and the second collector plate of the present invention.

[0126] Figures 21 to 24 This is a diagram illustrating various configurations of a second current collector according to an embodiment of the present invention.

[0127] Figure 25 and Figure 26 This is a diagram illustrating various configurations of the second current collector according to another embodiment of the present invention.

[0128] Figure 27 This is a partial cross-sectional view showing the lower structure of a cylindrical battery according to an embodiment of the present invention.

[0129] Figure 28 This is a diagram showing the lower surface of a cylindrical battery according to an embodiment of the present invention.

[0130] Figure 29 This is a schematic diagram of a battery pack illustrating an embodiment of the present invention.

[0131] Figure 30 This is a diagram of a car illustrating one embodiment of the present invention.

[0132] Figure 31 These are scanning microscope images of carbon nanotubes (current CNTs) that have been used in general applications.

[0133] Figure 32 These are scanning microscope images of the novel CNTs according to an embodiment of the present invention.

[0134] Figure 33 This table compares the physical properties of the standard CNT and the novel CNT.

[0135] Figures 34 to 37 It is a graph showing the surface resistivity and high-temperature lifetime characteristics of a conductive material at various ratios when single-particle-based active material particles are used as the anode active material.

[0136] Figure 38 For applicable BET specific surface area of ​​300m² 2 / g to 500m 2 / g of carbon nanotubes (novel CNTs) and their applicable BET of 200m 2 / g or more and less than 300m 2 The table shows a comparison of the solid powder content and viscosity of the anolyte solder and the resistivity on the MP coating and MP interface layer in the case of / g carbon nanotubes (existing CNTs).

[0137] Figure 39a This is a SEM image of the anolyte used in Example 2-1 of the present invention.

[0138] Figure 39b These are SEM images of the anodic active material used in Examples 2-2 of this invention.

[0139] Figure 39c These are SEM images of the anolyte used in Comparative Examples 2-2 of the present invention.

[0140] Figure 40a This is a graph showing the hot box test results of the 4680 battery manufactured according to Embodiment 1 of the present invention.

[0141] Figure 40b This is a graph showing the hot box test results of the 4680 battery manufactured according to Comparative Example 1 of the present invention.

[0142] Figure 40c This is a graph showing the hot box test results of the 4680 battery manufactured by Sample 1 of Example 2-1 and Comparative Example 2-1 of the present invention.

[0143] Figure 40d This is a graph showing the hot box test results of 4680 batteries manufactured using samples 2 and 3 of Example 2-1, samples 1 and 2 of Example 2-2, and Comparative Example 2-2.

[0144] Figure 41a This is a cross-sectional SEM image of the anode manufactured in Embodiment 2-1 of the present invention.

[0145] Figure 41b This is a cross-sectional SEM image of the anode manufactured in Comparative Example 2-1.

[0146] Figure 42a This is a graph showing the results of testing the resistance characteristics according to SOC when a coin cell including the anodes of Examples 3-3, Comparative Examples 3-1 and 3-2 of the present invention is charged to 4.2V.

[0147] Figure 42b This is a graph showing the test results of capacity retention and resistance increase rate obtained by charge-discharge cycle experiments of the 4680 batteries of Examples 3-1, 3-3 and Comparative Example 3-1 of the present invention.

[0148] Figure 43 This is a diagram illustrating an electrode assembly according to an embodiment of the present invention.

[0149] Figure 44 It shows along Figure 43 The cross-sectional view of the section cut by the cutting line A-A'.

[0150] Figure 45 and Figure 46 This is a diagram illustrating the process of manufacturing a cathode according to an embodiment of the present invention.

[0151] Figure 47 This is a perspective view of a cathode according to an embodiment of the present invention.

[0152] Figure 48 and Figure 49 This is a diagram illustrating the process of manufacturing an anode according to an embodiment of the present invention.

[0153] Figure 50 This is a perspective view of the anode of an embodiment of the present invention.

[0154] Figure 51 This is a diagram illustrating an electrode assembly of a comparative example of the present invention.

[0155] Figure 52 It shows along Figure 51 The cross-sectional view of the section cut by the cutting line B-B'.

[0156] Figure 53 This is a diagram illustrating the process of manufacturing a cathode according to a comparative example of the present invention.

[0157] Figure 54 This is a diagram illustrating the process of manufacturing an anode according to a comparative example of the present invention.

[0158] Figure 55 This is a graph showing the change in energy density in a battery using a mixture of silicon-based and carbon-based cathode active materials as the cathode active material, depending on the content and presence of silicon-based cathode active material doping. Detailed Implementation

[0159] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Before proceeding, the terms and words used in this specification and claims should not be limited to their ordinary or dictionary meanings. Given the principle that inventors may appropriately define terms and concepts in order to best illustrate their invention, they should be interpreted as conforming to the meaning and concept of the technical idea of ​​the present invention. Therefore, the embodiments described in this specification and the structures shown in the accompanying drawings are merely one of the most preferred embodiments of the present invention and do not represent the entirety of the technical idea of ​​the present invention. It should be understood that various equivalents and modifications could exist at the time of filing this application.

[0160] Furthermore, to aid in understanding the invention, the accompanying drawings are not shown to scale, but rather some of the constituent elements are depicted as enlarged versions. Additionally, in different embodiments, the same symbols are used for the same constituent elements.

[0161] The sizes and thicknesses of the various structures shown in the accompanying drawings are arbitrary for ease of explanation, and therefore the present invention is not necessarily limited to the illustrated cases. The thicknesses of the various layers and regions are enlarged in the drawings to clearly show them. Furthermore, the thicknesses of some layers and regions are enlarged in the drawings for ease of explanation.

[0162] Furthermore, when referring to a layer, membrane, region, plate, or other part as being "above" or "above" other parts, this includes not only the case where it is "directly above" other parts, but also the case where other parts exist between it. Conversely, when referring to a part as being "directly above" other parts, it means that there are no other parts between it. Additionally, being "above" or "above" the part that serves as a reference means being above or below the part that serves as a reference, and does not necessarily mean being "above" or "above" in the opposite direction of gravity.

[0163] Furthermore, throughout the specification, when a part is mentioned as "including" a certain constituent element, it does not exclude other constituent elements unless otherwise stated, but rather indicates that other constituent elements may also be included.

[0164] Additionally, throughout the instruction manual, "on a plane" refers to the view of the object from above, while "on a cross section" refers to the view of the object when viewed from the side as a section that is cut perpendicularly to the object.

[0165] First, refer to Figure 5 According to one embodiment of the present invention, the cylindrical battery 1 includes an electrode assembly 300, a battery casing 20, a first current collector 30, a cover plate 40, and battery terminals 60. Furthermore, the cylindrical battery 1 also includes a sealing gasket G1 and / or an insulating gasket G2 and / or a second current collector 50 and / or an insulator S.

[0166] The electrode assembly 300 described above includes a first electrode tab 11 and a second electrode tab 12. The electrode assembly 300 includes a first electrode having a first polarity, a second electrode having a second polarity, and a separation membrane sandwiched between the first electrode and the second electrode. The first electrode is either a cathode or an anode, and the second electrode is equivalent to an electrode having a polarity opposite to that of the first electrode. More specifically, the electrode assembly 300 is manufactured by winding a laminate formed by sequentially stacking the first electrode, the separation membrane, the second electrode, and the separation membrane at least once. That is, the electrode assembly 300 applicable in this invention is a gel roll type electrode assembly. Such a gel roll type electrode assembly 300 has a generally central portion formed along its height direction (with...). Figure 5 The cylindrical battery 1 shown has a winding center hole H1 extending in a direction parallel to its height direction. On the other hand, an additional separation membrane for achieving insulation between the electrode assembly 300 and the battery casing 20 is provided on the outer peripheral surface of the electrode assembly 300.

[0167] The aforementioned first electrode includes a first electrode current collector and a first electrode active material layer coated on one or both sides of the first electrode current collector. In the width direction of the aforementioned first electrode current collector (and... Figure 5 The cylindrical battery 1 shown has an uncoated portion on one side of its height direction (parallel to the height direction). When viewed with the first electrode extended, this uncoated portion extends from one side to the other along the length direction of the first electrode. This uncoated portion serves as the first electrode tab 11 as described above. The first electrode tab 11 is provided in the height direction (parallel to the height direction) of the electrode assembly 300 housed within the battery casing 20. Figure 5 The upper part of the cylindrical battery 1 shown is in the direction parallel to its height. The first electrode tab 11 mentioned above is, for example, a cathode tab.

[0168] The aforementioned second electrode includes a second electrode current collector and a second electrode active material layer coated on one or both sides of the second electrode current collector. In the width direction of the aforementioned second electrode current collector (and... Figure 5 The cylindrical battery 1 shown has an uncoated portion (without the active material of the second electrode) on one side of its height direction (parallel to the direction of height). When viewed with the second electrode extended, this uncoated portion extends along the length of the second electrode from one side to the other. This uncoated portion serves as the second electrode tab 12 as described above. The second electrode tab 12 is located at the lower part of the electrode assembly 300 housed within the battery casing 20 in the height direction. The second electrode tab 12 is, for example, an anode tab.

[0169] That is, the first electrode tab 11 and the second electrode tab 12 extend and protrude in opposite directions along the height direction of the cylindrical battery 1.

[0170] However, the present invention is not limited to this configuration of the electrode assembly 300.

[0171] The aforementioned battery casing 20 is a generally cylindrical housing with an opening on one side, and is made of a conductive metal material. The side surface of the battery casing 20 and the lower surface located on the opposite side of the opening (as shown in the image) Figure 5 The battery casing 20 is integrally formed with the lower part (as referenced below). That is, the battery casing 20 has a shape where its upper end is open and its lower end is closed in the height direction. The lower surface of the battery casing 20 is substantially flat. The battery casing 20 houses the electrode assembly 300 through an opening formed on one side in the height direction. The battery casing 20 also houses the electrolyte through the opening. However, the present invention is not limited to this shape of the battery casing 20.

[0172] The battery casing 20 is electrically connected to the electrode assembly 300. The battery casing 20 is connected to the first electrode tab 11 of the electrode assembly 300. Therefore, the battery casing 20 has the same polarity as the first electrode tab 11 electrically.

[0173] The battery casing 20 includes a rolled edge portion 21 formed at the end adjacent to the opening and pressed inward. The battery casing 20 has the rolled edge portion 21 formed at its upper end. The battery casing 20 also has a pressing portion 22 formed at an upper part higher than the rolled edge portion 21. The rolled edge portion 21 has a shape where the outer peripheral surface of the battery casing 20 is pressed in to a predetermined depth. The rolled edge portion 21 is formed on the upper part of the electrode assembly 300. The inner diameter of the battery casing 20 in the region where the rolled edge portion 21 is formed is smaller than the diameter of the electrode assembly 300.

[0174] The aforementioned rolled edge portion 21 provides a support surface for mounting the cover plate 40. Additionally, the aforementioned rolled edge portion 21 provides a support surface for mounting and engaging at least a portion of the periphery of the edge of the first current collector 30 (described later). That is, at least a portion of the periphery of the edge of the first current collector 30 of the present invention and / or the periphery of the edge of the cover plate 40 of the present invention are mounted on the upper surface of the aforementioned rolled edge portion 21. Figure 10 and Figure 11 As shown, in order to stably support at least a portion of the periphery of the first current collector 30 and / or the periphery of the edge of the cover plate 40, the upper surface of the rolled edge portion 21 may also have a shape in which at least a portion extends along a direction that is substantially parallel to the lower surface of the battery casing 20, i.e., substantially perpendicular to the sidewall of the battery casing 20.

[0175] The aforementioned crimping portion 22 is formed on the upper part of the rolled edge portion 21. The crimping portion 22 extends and bends around the edge of the cover plate 40 disposed on the upper part of the rolled edge portion 21. Based on the shape of this crimping portion 22, the cover plate 40 is fixed to the rolled edge portion 21. Alternatively, the crimping portion 22 can be omitted, and the cover plate 40 can be used to cover and fix the opening of the battery casing 20 using other fixing structures.

[0176] However, the present invention does not preclude the possibility that the battery casing 20 may not have such a rolled edge portion 21 and / or a crimped portion 22. In the case where the battery casing 20 does not have the rolled edge portion 21 and / or the crimped portion 22 in the present invention, the electrode assembly 300 and / or the cover plate 40 and / or the battery casing 20 may be fixed and / or the cover plate 40 may be fixed and / or the battery casing 20 may be sealed, for example, by adding a component that serves as a limiter relative to the electrode assembly 300 and / or adding a structure that mounts the cover plate 40 and / or welding between the battery casing 20 and the cover plate 40.

[0177] The closed end of the battery casing 20, i.e., the upper region, has a thickness of approximately 0.5 mm to 1.0 mm, more preferably approximately 0.6 mm to 0.8 mm. The sidewall portion forming the outer peripheral surface of the battery casing 20 has a thickness of approximately 0.3 mm to 0.8 mm, more preferably approximately 0.40 mm to 0.60 mm. According to one embodiment of the invention, a gold plating layer is formed on the battery casing 20. In this case, the gold plating layer includes, for example, nickel (Ni). The thickness of the gold plating layer is approximately 1.5 μm to 6.0 μm.

[0178] The thinner the battery casing 20, the larger the internal space, thereby increasing the energy density and producing a cylindrical battery 1 with a large capacity. Conversely, the thicker the casing, the less likely the flame will propagate continuously to adjacent cells during an explosion test, which is advantageous from a safety perspective.

[0179] The thinner the gold plating layer, the easier it is to corrode; the thicker the plating layer, the more difficult the manufacturing process becomes or the higher the possibility of gold plating peeling. All these factors must be considered to determine the optimal thickness of the battery casing 20 and the optimal thickness of the gold plating layer. Furthermore, all these factors must be considered to control the thickness of the sealing portion and the sidewall portion of the battery casing 20 separately.

[0180] Below, refer to Figure 5 and Figure 9 The first current collector 30 of one embodiment of the present invention will be described in detail below.

[0181] First, refer to Figure 5 and Figure 6In one embodiment of the present invention, a first current collector 30 is housed inside the battery casing 20 and electrically connected to the electrode assembly 300, and also electrically connected to the battery casing 20. That is, the first current collector 30 electrically connects the electrode assembly 300 and the battery casing 20.

[0182] The first current collector 30 includes a support portion 31 disposed on one side of the electrode assembly 300, a plurality of first electrode tab coupling portions 32 extending from the support portion 31 and engaging with the first electrode tab 11, and a plurality of first housing coupling portions 33 extending from the support portion 31 and engaging with the inner side of the battery casing 20. The first electrode tab coupling portions 32 and the first housing coupling portions 33 are indirectly connected through the support portion 31 and are not directly connected to each other. Therefore, the possibility of damage to the coupling portions of the first current collector 30 and the electrode assembly 300 and the coupling portions of the first current collector 30 and the battery casing 20 when the cylindrical battery 1 of the present invention is subjected to external impact can be minimized.

[0183] The aforementioned support portion 31 and multiple first tab joint portions 32 are disposed on the upper part of the electrode assembly 300, and are disposed closer to the lower part than the rolled edge portion 21 when the battery casing 20 forms a rolled edge portion 21.

[0184] The aforementioned support portion 31 has a winding hole H1 formed at approximately the center of the electrode assembly 300 and a first current collector hole H2 formed at a corresponding position. The winding hole H1 and the first current collector hole H2, which are interconnected, serve as channels for inserting a welding rod or irradiating a laser for welding between the battery terminal 60 and the second current collector 50, or for welding between the battery terminal 60 and the lead tab (not shown), as described later.

[0185] The aforementioned plurality of first tab coupling portions 32 have a shape that extends radially from the support portion 31 toward the sidewall of the battery casing 20. The plurality of first tab coupling portions 32 are arranged separately from each other along the periphery of the support portion 31. On the other hand, in order to ensure bonding strength and reduce resistance by increasing the bonding area between the first current collector 30 and the electrode assembly 300, both the first tab coupling portions 32 and the support portion 31 can be coupled to the first electrode tab 11. The end of the first electrode tab 11 is formed in a shape that is curved parallel to the first tab coupling portion 32. When the end of the first electrode tab 11 is formed in this way and coupled to the first tab coupling portion 32 in a state parallel to the first tab coupling portion 32, the bonding area is increased, thereby improving the bonding strength and reducing the resistance. Furthermore, the overall height of the electrode assembly 300 is minimized, thereby increasing the energy density.

[0186] The aforementioned plurality of first housing joint portions 33 have a shape that extends generally radially toward the sidewall of the battery casing 20 from the support portion 31 of the first current collector plate 30. The plurality of first housing joint portions 33 are arranged separately from each other along the periphery of the support portion 31. At least one first housing joint portion 33 is arranged between adjacent first electrode tab joint portions 32. The plurality of first housing joint portions 33 are joined to the rolled edge portion 21, for example, on the inner side of the battery casing 20. Specifically, the first housing joint portions 33 are joined to the upper surface of the rolled edge portion 21. In the cylindrical battery 1 of the present invention, when such a structure is applied, the first housing joint portions 33 are naturally mounted to the rolled edge portion 21 by accommodating the electrode assembly 300, in which the first current collector plate 30 is joined, within the battery casing 20. Therefore, the welding process between the battery casing 20 and the first current collector plate 30 is easily performed. Furthermore, the upper surface of the rolled edge portion 21 extends in a direction approximately parallel to the lower surface of the battery casing 20, i.e., approximately perpendicular to the sidewall of the battery casing 20. The first casing joint portion 33 also extends in the same direction, thereby ensuring that the first casing joint portion 33 is stably in contact with the rolled edge portion 21. Moreover, by ensuring that the first casing joint portion 33 is stably in contact with the rolled edge portion 21, welding between the two components is smoothly achieved, thereby increasing the bonding force between the two components and minimizing the increase in resistance at the joint.

[0187] Next, refer to Figures 7 to 11 The aforementioned first outer casing joint 33 includes a first contact portion 33a that is attached to the inner side of the battery casing 20 and a first connecting portion 33b that connects the support portion 31 to the first contact portion 33a.

[0188] The first contact portion 33a is bonded to the inner side surface of the battery casing 20. When the battery casing 20 has a rolled edge portion 21, as described above, the first contact portion 33a is bonded to the rolled edge portion 21. In this case, as described above, to achieve stable contact and bonding, both the rolled edge portion 21 and the first contact portion 33a have a shape that extends in a direction substantially parallel to the lower surface of the battery casing 20, i.e., substantially perpendicular to the sidewall of the battery casing 20.

[0189] The aforementioned first connecting portion 33b includes at least one first bent portion B1, which changes its extension direction between the support portion 31 and the first contact portion 33a. That is, the aforementioned first connecting portion 33b has a structure similar to a spring or a pleated structure that can be contracted and stretched within a certain range. Even with a certain degree of dispersion of the electrode assembly 300 within a certain range, this structure of the first connecting portion 33b allows the first contact portion 33a to be tightly adhered to the rolled edge portion 21 during the process of housing the electrode assembly 300, which is coupled with the first current collector 30, inside the battery casing 20.

[0190] For example, preferably, the vertical distance D between the first contact portion 33a and the support portion 31 when the first current collector plate 30 is not subjected to external force and does not deform is the same as the vertical distance between the upper surface of the rolled edge portion 21 and the support portion 31 when the electrode assembly 300 with the first current collector plate 30 is installed inside the battery casing 20, or smaller within the stretchable range of the first connecting portion 33b. When the first connecting portion 33b satisfies such conditions, when the electrode assembly 300 with the first current collector plate 30 is installed inside the battery casing 20, the contact portion 33a naturally adheres tightly to the rolled edge portion 21.

[0191] Moreover, even with such a retractable and stretchable structure in the cylindrical battery 1 (refer to...) Figure 5 During use, the electrode assembly 300 may move up and down due to vibration and / or impact. This structure can also mitigate the impact caused by the movement of the electrode assembly 300 to a certain extent. Specifically, the retractable and stretchable structure of the first connecting portion 33b provides a buffering effect to prevent impact from being transmitted to the joint between the first contact portion 33a and the battery casing 20, and the joint between the first electrode tab joint portion 32 and the first electrode tab 11 (see reference). Figures 5 to 9 ).

[0192] then, Figure 12 A first current collector 30 according to another embodiment of the present invention is shown. The first current collector 30 of another embodiment of the present invention is the same as the first current collector 30 described above (illustratively referred to). Figure 6 The first current collector (30) described above differs from the first current collector 30 only in the shape of the first contact portion 33a. Otherwise, it is essentially the same in structure as the first current collector 30 described above.

[0193] Reference Figure 5 and Figure 12The first contact portion 33a has a shape in which at least a portion extends along the inner peripheral surface of the battery casing 20. In this case, in order to maximize the contact area, the first current collector 30 is configured such that the sum of the extension lengths of the first contact portions 33a of each of the plurality of first casing joint portions 33 is approximately the same as the inner periphery of the battery casing 20.

[0194] then, Figure 5 , Figure 13 and Figure 14 The illustration shows a first current collector 30 according to yet another embodiment of the present invention. The first current collector 30 of this further embodiment is illustrated in the illustration, and is similar to the first current collector 30 of the above embodiments (see reference illustratively). Figure 6 and Figure 12 The first current collector 30 described above differs from the first current collector 30 only in that it also has a second housing joint 34; otherwise, it is substantially the same in structure as the first current collector 30 described above.

[0195] The aforementioned second housing connection portion 34 extends from the end of the first tab connection portion 32 and is connected to the inner surface of the battery housing 20. Such a second housing connection portion 34 is provided at at least one end of the plurality of the aforementioned first tab connection portions 32. The aforementioned second housing connection portion 34 includes a second contact portion 34a connected to the inner surface of the battery housing 20 and a second connecting portion 34b connecting the support portion 31 to the second contact portion 34a.

[0196] The second contact portion 34a is attached to the inner side surface of the battery casing 20. When the battery casing 20 has a rolled edge portion 21, the second contact portion 34a is attached to the rolled edge portion 21 in the same way as the first contact portion 33a. In this case, as described above, to achieve stable contact and attachment, both the rolled edge portion 21 and the second contact portion 34a are shaped to extend in a direction substantially parallel to the lower surface of the battery casing 20, i.e., substantially perpendicular to the sidewall of the battery casing 20.

[0197] On the other hand, although not illustrated, such as Figure 12 The first contact portion 33a shown in the figure also has a shape in which at least a portion of the second contact portion 34a extends along the inner peripheral surface of the battery casing 20. In this case, in order to maximize the contact area between the first current collector 30 and the battery casing 20, the first current collector 30 is configured such that the sum of the extension lengths of the second contact portions 34a of each of the plurality of second casing joint portions 34 is approximately the same as the inner periphery of the battery casing 20.

[0198] The second connecting portion 34b described above, like the first connecting portion 33b described above, also has at least one second curved portion B2, which changes its extension direction between the first tab joint portion 32 and the second contact portion 34a. Through the formation of the second curved portion B2, the second connecting portion 34b has a retractable and stretchable structure, thereby providing advantages in the assembly process of the cylindrical battery 1 and a buffering effect, which are the same as those described above.

[0199] The accompanying drawings of this invention illustrate a case where only one of the aforementioned second curved portions B1 is provided, but the invention is not limited thereto, as illustrated above. Figure 8 and Figure 9 Similarly, the second curved portion B2 can also be formed in multiple ways, just as the first connecting portion 33b is described.

[0200] Reference Figure 5 The cover plate 40 covers the opening formed on one side of the battery casing 20. When the battery casing 20 of the present invention has a rolled edge portion 21, the cover plate 40 is mounted onto the rolled edge portion 21 formed on the battery casing 20. Alternatively, when the battery casing 20 of the present invention has a press-fit portion 22, the cover plate 40 is fixed by the press-fit portion 22. In this case, to improve the fixing force and the sealing of the battery casing 20, a sealing gasket G1 is sandwiched between the battery casing 20 and the cover plate 40, and between the first current collector 30 and the cover plate 40. However, in the present invention, the cover plate 40 is not a component used as a current channel. Therefore, as long as the battery casing 20 and the cover plate 40 can be firmly fixed by welding or by using other components to ensure the sealing of the opening of the battery casing 20, it is not necessary to use such a sealing gasket G1.

[0201] To ensure rigidity, the cover plate 40 is made of, for example, a metal material. In the cylindrical battery 1 of the present invention, even if the cover plate 40 is made of a conductive metal material, it may not be polarized. Non-polarization means that the cover plate 40 is electrically insulated from the battery casing 20 and the battery terminals 60 described below. Therefore, the cover plate 40 is not used as an anode or cathode terminal. Therefore, the cover plate 40 does not need to be electrically connected to the electrode assembly 300 and the battery casing 20, and its material does not necessarily need to be made of a conductive metal.

[0202] On the other hand, taking the case where the sealing gasket G1 is applied as an example, the sealing gasket G1 has a generally annular shape that surrounds the cover plate 40. The sealing gasket G1 simultaneously covers the upper surface, lower surface, and side surface of the cover plate 40. The radial length of the portion of the sealing gasket G1 covering the lower surface of the cover plate 40 is less than or equal to the radial length of the portion of the sealing gasket G1 covering the upper surface of the cover plate 40. If the radial length of the portion of the sealing gasket G1 covering the lower surface of the cover plate 40 is too long, the sealing gasket G1 will exert pressure on the first current collector 30 during the vertical compression of the battery casing 20, which may cause damage to the first current collector 30 or the battery casing 20. Therefore, it is necessary to make the radial length of the portion of the sealing gasket G1 covering the lower surface of the cover plate 40 small to a certain level. For example, as Figure 5 As shown, the radial length of the portion of the sealing gasket G1 covering the lower surface of the cover plate 40 is less than the radial length of the portion of the sealing gasket G1 covering the upper surface of the cover plate 40. Alternatively, the radial length of the portion of the sealing gasket G1 covering the lower surface of the cover plate 40 is the same as the radial length of the portion of the sealing gasket G1 covering the upper surface of the cover plate 40.

[0203] On the other hand, the cover plate 40 includes a vent 41, which is formed to prevent an increase in internal pressure due to gas generated inside the battery casing 20. The vent 41 is formed in a portion of the cover plate 40, corresponding to a structurally weaker area than the surrounding region, making it more susceptible to breakage when internal pressure is applied. The vent 41 is a region with a thickness, for example, thinner than the surrounding region. Therefore, when an abnormality occurs in the cylindrical battery 1, causing the internal pressure of the battery casing 20 to rise above a certain level, the vent 41 breaks, releasing the gas generated inside the battery casing 20. The vent 41 is formed, for example, by notching on one or both sides of the cover plate 40, thereby partially reducing the thickness of the battery casing 20.

[0204] The battery terminal 60 is electrically connected to the second electrode tab 12. The battery terminal 60 penetrates the battery casing 20 on the side opposite to the open portion of the battery casing 20 and is electrically connected to the second electrode tab 12 of the electrode assembly 300. The battery terminal 60 includes a terminal protrusion portion 60a and a terminal insertion portion 60b. The terminal protrusion portion 60a protrudes outward from the closed surface of the battery casing 20. The terminal protrusion portion 60a is located approximately at the center of the closed surface of the battery casing 20. The maximum diameter of the terminal protrusion portion 60a is larger than the maximum diameter of the through hole formed in the battery casing 20. The terminal insertion portion 60b penetrates approximately at the center of the closed surface of the battery casing 20 and is electrically connected to the second electrode tab 12. The terminal insertion portion 60b is riveted to the inner surface of the battery casing 20. That is, the end of the terminal insertion portion 60b has a twisted shape toward the inner surface of the battery casing 20. The maximum diameter of the end of the terminal insertion portion 60b is larger than the maximum diameter of the through hole in the battery casing 20. A portion of the aforementioned battery terminal 60 protrudes to the outside of the battery casing 20, while the remaining portion is located inside the battery casing 20. The battery terminal 60 is electrically connected to the electrode assembly 300, for example, by connecting to a second current collector plate 50 bonded to the second electrode tab 12 (described later) or by connecting to a lead tab (not shown) bonded to the second electrode tab 12. The inner surface of the terminal insertion portion 60b is soldered to the second current collector plate 50 connected to the second electrode tab 12. An insulator S (described later) is sandwiched between the second current collector plate 50 and the inner surface of the battery casing 20.

[0205] Considering the polarity and function of the battery terminal 60, it needs to be insulated from the battery casing 20, which has the opposite polarity. For this purpose, an insulating washer G2 is applied between the battery terminal 60 and the battery casing 20. Alternatively, insulation can be achieved by coating a portion of the surface of the battery terminal 60 with an insulating material. Alternatively, to prevent the battery terminal 60 and the battery casing 20 from contacting each other, they can be arranged separately, and the battery terminal 60 can be structurally and robustly fixed. Alternatively, multiple methods described above can be applied together.

[0206] That is, the cylindrical battery 1 of the present invention has a structure in which a pair of electrode terminals 60 and T1 are located in the same direction. Therefore, when multiple cylindrical batteries 1 are electrically connected, only one side of the cylindrical battery 1 needs to be arranged for the electrical connection components such as busbars. This simplifies the battery pack structure and increases the energy density. In addition, the cylindrical battery 1 has a structure that allows one side of the battery casing 20, which has a generally flat shape, to be used as the first electrode terminal T1, thereby ensuring a sufficient contact area when the electrical connection components such as busbars are joined to the first electrode terminal T1. As a result, the cylindrical battery 1 can ensure sufficient contact strength between the electrical connection components and the first electrode terminal T1, reducing the resistance at the contact point to a preferred level.

[0207] On the other hand, when the insulating washer G2 is used for electrical insulation and riveting is used for fixing the battery terminal 60, the insulating washer G2 is deformed together with the battery terminal 60 during riveting and bends towards the inner side of the closed portion at the upper end of the battery casing 20. When the insulating washer G2 is made of resin, it is bonded to the battery casing 20 and the battery terminal 60 by heat fusion. In this case, the airtightness of the interface between the insulating washer G2 and the battery terminal 60, and between the insulating washer G2 and the battery casing 20, can be strengthened.

[0208] In this invention, the entire surface of the battery casing 20 is used as the first electrode terminal T1. For example, when the first electrode tab 11 is a cathode tab, the first electrode terminal T1 is a cathode terminal. The cylindrical battery 1 of the present invention has a structure in which the battery terminal 60 exposed on the lower surface opposite to the open portion of the battery casing 20 and the remaining area on the lower surface of the battery casing 20 other than the area occupied by the battery terminal 60 are used as the second electrode terminal T2 and the first electrode terminal T1, respectively. Therefore, when multiple cylindrical batteries 1 are electrically connected, the cylindrical battery 1 of the present invention can connect all the anodes / cathodes in one direction, thus simplifying the electrical connection structure. In addition, the cylindrical battery 1 of the present invention has a structure in which most of the lower surface opposite to the open portion of the battery casing 20 is used as the electrode terminal, thus ensuring sufficient area for welding components used for electrical connection.

[0209] On the other hand, in this invention, the entire surface of the battery casing 20 is used as the first electrode terminal T1. When the aforementioned first electrode tab 11 is a cathode tab, the first electrode terminal T1 is the cathode terminal. The cylindrical battery 1 of this invention can use the battery terminal 60 exposed on the lower surface opposite to the open portion of the battery casing 20, and the remaining area on the lower surface of the battery casing 20 excluding the area occupied by the battery terminal 60, as the second electrode terminal T2 and the first electrode terminal T1, respectively. Therefore, when multiple cylindrical batteries 1 are electrically connected, the anode / cathode of the cylindrical battery 1 of this invention can be connected in one direction, thus simplifying the electrical connection structure. Furthermore, since the cylindrical battery 1 of this invention can use a large portion of the lower surface opposite to the open portion of the battery casing 20 as an electrode terminal, sufficient area for welding components used to achieve the electrical connection can be ensured.

[0210] Reference Figure 15 The first current collector 30 of the present invention includes at least one injection hole H4. The injection hole H4 is, for example, provided in a first tab connection portion 32. When multiple first tab connections 32 are formed, the injection hole H4 is provided in at least one first tab connection portion 32. The injection hole H4 is, for example, respectively provided on one side or both sides of at least one bonding wire W formed on the first tab connection portion 32. (Refer to...) Figure 5 and Figure 15 In manufacturing the cylindrical battery 1 according to one embodiment of the present invention, electrolyte is injected after the assembly including the electrode assembly 300 and the first current collector 30 is housed inside the battery casing 20. This improves the injectability when injected through the injection hole H4.

[0211] Reference Figure 16 The first connecting portion 33b of the first outer shell joint 33 and / or the second connecting portion 34b of the second outer shell joint 34 of the present invention have a shape that bends once. It can be configured to be oriented towards... Figure 7 and Figure 14 The diagram shows bending shapes in different directions. Specifically, the first bent portion B1 formed on the first connecting portion 33b and / or the second bent portion B2 formed on the second connecting portion 34b have a bending shape near the cylindrical battery 1 (see reference). Figure 5The first connecting portion 33b and / or the second connecting portion 34b are shaped to protrude towards the center of the battery casing 20. The bending direction of these first connecting portions 33b and / or the second connecting portion 34b is designed to prevent damage at the junction of the first current collector plate 30 and the electrode assembly 300, and / or the junction of the first current collector plate 30 and the battery casing 20, during the sizing process. Sizing refers to a compression process in which the height occupied by the rolled edge portion 21 of the battery casing 20 is reduced to decrease the overall height of the cylindrical battery 1 during manufacturing. The degree of damage to the welded portion after the sizing process was confirmed by examining whether the aforementioned bent portions B1 and B2 were formed and by changing the protruding direction of the bent portions B1 and B2. The results showed that almost no damage occurred in the cylindrical battery 1 with a structure in which the bent portions B1 and B2 protrude towards the center of the cylindrical battery 1.

[0212] Below, refer to Figures 17 to 30 The cylindrical battery 1 described above will be explained in more detail below. In the following description, when the same constituent elements as those described above are presented, there are alternative embodiments that may be selectively applied. Furthermore, some content in the following description overlaps with the content described above.

[0213] Reference Figure 17 and Figure 18 According to one embodiment of the present invention, a cylindrical battery 1 includes an electrode assembly 300, a battery casing 20, a cover plate 40, a second current collector 50, and battery terminals 60. In addition to the aforementioned components, the cylindrical battery 1 also includes a sealing gasket G1 and / or an insulating gasket G2 and / or an insulator S and / or a first current collector 30.

[0214] The electrode assembly 300 includes a first electrode tab 11 and a second electrode tab 12. The second electrode tab 12 is disposed on the upper part of the electrode assembly 300 housed in the battery casing 20 in the height direction (parallel to the Z-axis). The first electrode tab 11 is disposed on the lower part of the electrode assembly 300 housed in the battery casing 20 in the height direction (parallel to the Z-axis).

[0215] The second electrode tab 12 and the first electrode tab 11 extend in opposite directions along the width direction of the electrode assembly 300, i.e., the height direction of the cylindrical battery 1 (parallel to the Z-axis). The second electrode tab 12 extends toward the closed portion of the battery casing 20, and the first electrode tab 11 extends toward the open portion of the battery casing 20.

[0216] The battery casing 20 is a generally cylindrical housing with an opening at the bottom, and is made of a conductive material such as metal. The opening is formed at the lower end of the battery casing 20, and a closed portion is formed at the upper end. The battery casing 20 houses the electrode assembly 300 and the electrolyte through the opening at the bottom. (See reference...) Figure 19 and Figure 28 The battery casing 20 has a rolled edge portion 21 and a pressing portion 22 formed at its lower end. The rolled edge portion 21 is located at the lower part of the electrode assembly 300. The rolled edge portion 21 is formed by pressing the battery casing 20 into the periphery of its outer surface. The rolled edge portion 21 prevents the electrode assembly 300, which has a size that is approximately corresponding to the width of the battery casing 20, from falling off through the opening formed at the lower end of the battery casing 20, and also serves as a support for mounting the cover plate 40.

[0217] The aforementioned crimping portion 22 is formed at the lower part of the rolled edge portion 21. The aforementioned crimping portion 22 has a shape that extends and bends around the outer peripheral surface of the cover plate 40 disposed below the rolled edge portion 21 and a portion of the lower surface of the cover plate 40.

[0218] Reference Figure 18 and Figure 27 The cover plate 40 seals the opening at the lower end of the battery casing 20. That is, the cover plate 40 forms the lower surface of the cylindrical battery 1.

[0219] As described later, a cylindrical battery 1 according to one embodiment of the present invention has a structure in which an anode terminal and a cathode terminal are located at the upper part, thus the upper structure is more complex than the lower structure. Therefore, in order to smoothly discharge the gas generated inside the battery casing 20, an exhaust portion 41 is formed on the cover plate 40 constituting the lower surface of the cylindrical battery 1. Figure 27 As shown, the lower end of the cover plate 40 is preferably positioned higher than the lower end of the battery casing 20. In this case, even if the lower end of the battery casing 20 reaches the ground or the bottom surface of the casing constituting the module or assembly structure, the cover plate 40 will not reach the ground or the bottom surface of the casing constituting the module or assembly structure. Therefore, it is possible to prevent the pressure required for the venting section 41 to break due to the weight of the cylindrical battery 1 from differing from the design value, thereby ensuring that the venting section 41 breaks smoothly.

[0220] On the other hand, in the aforementioned exhaust section 41, as Figure 27 and Figure 28In the case of a closed-loop configuration, from the perspective of ease of breakage, a longer distance from the center of the cover plate 40 to the exhaust portion 41 is more advantageous. This is because, when the same exhaust pressure is applied, a longer distance from the center of the cover plate 40 to the exhaust portion 41 results in a greater force acting on the exhaust portion 41, making it easier to break. Furthermore, from the perspective of smooth gas discharge, a longer distance from the center of the cover plate 40 to the exhaust portion 41 is more advantageous. From this viewpoint, the exhaust portion 41 is preferably located along the area surrounding the edge of the cover plate 40 downwards (within a certain range). Figure 17 It is formed around the edge of a roughly flat area that protrudes downwards (based on the reference direction).

[0221] The present invention Figure 28 The illustration shows the exhaust portion 41 being formed continuously in a roughly circular shape on the cover plate 40, but the present invention is not limited thereto. The exhaust portion 41 may also be formed discontinuously in a roughly circular shape on the cover plate 40, or it may be formed in a roughly straight line shape or other other shapes.

[0222] Reference Figures 18 to 20 The second current collector 50 is attached to the upper part of the electrode assembly 300. The second current collector 50 is made of a conductive metal material and is connected to the second electrode tab 12.

[0223] Reference Figure 20 The second current collector 50 is bonded to the joint surface formed by bending the end of the second electrode tab 12 in a direction parallel to the second current collector 50. The bending direction of the second electrode tab 12 is, for example, close to the winding center hole H1 of the electrode assembly 300. With this bending shape, the space occupied by the second electrode tab 12 is reduced, thereby increasing the energy density. Furthermore, by increasing the bonding area between the second electrode tab 12 and the second current collector 50, the bonding force can be improved, and the resistance can be reduced.

[0224] Reference Figures 18 to 20 , Figures 21 to 24 The second current collector 50 includes an edge portion 51, a second electrode tab connection portion 52, and a terminal connection portion 53. The edge portion 51 has a generally rim shape with a central empty space E. The accompanying drawings only illustrate the case where the edge portion 51 has a generally circular rim shape, but the invention is not limited to this. Unlike the illustrated case, the edge portion 51 may also have a generally square rim shape or other other forms.

[0225] The second electrode tab 52 extends inward from the edge portion 51 and engages with the first electrode tab 11. The terminal engagement portion 53 is separate from the second electrode tab 52 and located inside the edge portion 51. The terminal engagement portion 53 is bonded to the battery terminal 60 by welding. The terminal engagement portion 53 is, for example, located in the center of the inner space of the edge portion 51. The terminal engagement portion 53 is positioned corresponding to the hole formed in the winding center hole H1 of the electrode assembly 300.

[0226] The aforementioned second tab connection portion 52 and terminal connection portion 53 are not directly connected but are arranged separately and electrically connected through the edge portion 51. Thus, in one embodiment of the present invention, the second current collector 50 has a structure in which the second tab connection portion 52 and the terminal connection portion 53 are not directly connected but connected through the edge portion 51. This allows for the dispersion of impacts applied to the connection between the second tab connection portion 52 and the second electrode tab 12, and the connection between the terminal connection portion 53 and the battery terminal 60, in the event of an impact and / or vibration to the cylindrical battery 1. Therefore, the second current collector 50 of the present invention can minimize or prevent damage to the welded joints caused by external impacts. The second current collector 50 of the present invention has a structure in which stress concentrates at the connection between the edge portion 51 and the terminal connection portion 53 when an external impact is applied. However, this connection is not a welded joint for achieving the connection between components, thus preventing product defects caused by welded joint damage due to external impacts.

[0227] The second current collector 50 also includes a connector 54 extending inward from the edge 51 and connecting to the terminal joint 53. At least a portion of the connector 54 is narrower than the second tab joint 52. In this case, the resistance of the connector 54 increases, resulting in a greater resistance compared to other parts when current flows through the connector 54. Consequently, in the event of an overcurrent, a portion of the connector 54 breaks, blocking the overcurrent. The width of the connector 54 is adjusted to an appropriate level to take into account this overcurrent blocking function.

[0228] The aforementioned connector 54 has a tapered portion 54a whose width gradually narrows from the inner side of the edge portion 51 along the direction close to the terminal joint portion 53. With the aforementioned tapered portion 54a, the rigidity of the component can be improved at the connection between the connector 54 and the edge portion 51.

[0229] The aforementioned second tab coupling portions 52 are formed in multiples. These multiple second tab coupling portions 52 are arranged at equal intervals along the extending direction of the edge portion 51. The extension lengths of each of the multiple second tab coupling portions 52 are the same. The aforementioned terminal coupling portion 53 is arranged such that it is surrounded by the multiple second tab coupling portions 52. The aforementioned connector 54 is located between a pair of adjacent second tab coupling portions 52. In this case, the distance from the connector 54 along the extending direction of the edge portion 51 to any one of the pair of second tab coupling portions 52 is the same as the distance from the connector 54 along the extending direction of the edge portion 51 to the other of the pair of second tab coupling portions 52.

[0230] The aforementioned connectors 54 are formed in multiple units. Each of the multiple connectors 54 is disposed between a pair of adjacent second electrode lugs 52. The multiple connectors 54 are arranged at equal intervals along the extending direction of the edge portion 51.

[0231] As described above, when multiple second tab joints 52 and / or connectors 54 are formed, the flow of current from the second tab joint 52 to the connector 54 or from the connector 54 to the second tab joint 52 can be smoothly realized when the distance between the second tab joints 52 and / or the distance between the connectors 54 and / or the distance between the second tab joint 52 and the connector 54 is constant.

[0232] Reference Figure 25 and Figure 26 The aforementioned connector 54 includes a slotted portion N formed in a manner that partially reduces the width of the connector 54. With the aforementioned slotted portion N, the resistance in the area where the slotted portion N is formed increases, thereby enabling the current to be quickly blocked when an overcurrent occurs.

[0233] When the connector 54 has a tapered portion 54a, the slotted portion N is positioned closer to the tapered portion 54a than the terminal connection portion 53. In this case, the structure of the tapered portion 54a, whose width gradually narrows, allows the slotted portion N to be formed in a region adjacent to a region with high heat generation, thereby enabling more rapid interruption of overcurrent.

[0234] Reference Figures 17 to 19 and Figure 21 The battery terminal 60 is made of a conductive metal and is coupled to the terminal connection portion 53 of the second current collector 50. The battery terminal 60 passes through a closed portion located opposite the open portion of the battery casing 20. When the cylindrical battery 1 of the present invention includes an insulator S, the battery terminal 60 is coupled to the terminal connection portion 53 of the second current collector 50 via the insulator S.

[0235] Thus, the battery terminal 60 is electrically connected to the second electrode tab 12 of the electrode assembly 300 via the second current collector 50, thereby possessing a second polarity. Therefore, the battery terminal 60 is used as the second electrode terminal of the cylindrical battery 1 of the present invention. Furthermore, in the cylindrical battery 1 of the present invention, the generally flat surface formed on the closed portion side of the battery casing 20 possessing the first polarity is used as the first electrode terminal T1. (Refer to...) Figure 17 In the cylindrical battery 1 of the present invention, a busbar U is connected to the second electrode terminal T2 and the first electrode terminal T1, respectively. In order to ensure sufficient contact area for contacting the busbar U, the width D1 of the area of ​​the second electrode terminal T2 exposed to the outside of the battery casing 20 is set to approximately 10% to 60% relative to the width D2 of the upper surface of the first electrode terminal T1, i.e., the battery casing 20.

[0236] Reference Figure 18 and Figure 19 , Figure 21 The insulator S is disposed between the second current collector 50 and the inner surface of the battery casing 20. The insulator S prevents contact between the second current collector 50 and the battery casing 20. The insulator S covers the upper part of the second current collector 50 and the upper edge of the electrode assembly 300. This prevents a short circuit caused by contact between the uncoated outer peripheral portion of the electrode assembly 300 and the inner surface of the battery casing 20, which has a different polarity. The insulator S is also sandwiched between the upper end of the outer peripheral surface of the electrode assembly 300 and the inner surface of the battery casing 20. This is to prevent contact between the second electrode tab 12, which extends towards the closure portion of the battery casing 20, and the inner peripheral surface of the battery casing 20.

[0237] When the cylindrical battery 1 of the present invention includes an insulator S, the battery terminal 60 is connected to the second current collector 50 through the insulator S. Thus, in order for the battery terminal 60 to pass through, the insulator S has an opening formed at a position corresponding to the terminal connection portion 53 of the second current collector 50.

[0238] Reference Figure 17 The first current collector 30 is attached to the lower part of the electrode assembly 300. The first current collector 30 is made of a conductive metal and is attached to the first electrode tab 11. Furthermore, the current collector 50 is electrically connected to the battery casing 20. The area around the edge of the first current collector 30 is sandwiched between the inner side of the battery casing 20 and the sealing gasket G1 and is thus fixed. In this case, the first current collector 30 can also be welded to a mounting surface formed by the rolled edge 21 of the battery casing 20.

[0239] Reference Figure 20The first current collector 30 is bonded to the first electrode tab 11, and the bonding surface is formed by bending the end of the first electrode tab 11 in a direction parallel to the first current collector 30. The bending direction of the first electrode tab 11 is, for example, close to the winding center hole H1 of the electrode assembly 300. With this bending shape, the space occupied by the first electrode tab 11 is reduced, thereby increasing the energy density. Furthermore, it increases the bonding force between the first electrode tab 11 and the first current collector 30, thus reducing resistance.

[0240] Preferably, the cylindrical battery cell is, for example, a cylindrical battery cell with a shape factor ratio (defined as the ratio of the diameter of the cylindrical battery cell to its height, i.e., the ratio of diameter Φ to height H) that is approximately greater than 0.4.

[0241] Here, the shape factor refers to the value representing the diameter and height of the cylindrical battery. An embodiment of the cylindrical battery of this invention includes, for example, the 46110 battery, 48750 battery, 48110 battery, 48800 battery, and 46800 battery. In the shape factor value, the first two digits represent the diameter of the battery, the next two digits represent the height of the battery, and the last digit indicates that the cross-section of the battery is circular.

[0242] One embodiment of the present invention is a generally cylindrical battery with a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor ratio of approximately 0.518.

[0243] Another embodiment of the battery is a cylindrical battery that is generally cylindrical, with a diameter of approximately 48 mm, a height of approximately 75 mm, and a shape factor ratio of approximately 0.640.

[0244] Another embodiment of the battery is a generally cylindrical battery with a diameter of approximately 48 mm, a height of approximately 110 mm, and a shape factor ratio of approximately 0.518.

[0245] Another embodiment of the battery is a generally cylindrical battery with a diameter of approximately 48 mm, a height of approximately 80 mm, and a shape factor ratio of approximately 0.600.

[0246] Another embodiment of the battery is a generally cylindrical battery with a diameter of approximately 46 mm, a height of approximately 80 mm, and a shape factor ratio of approximately 0.575.

[0247] Previously, batteries with a form factor ratio of approximately 0.4 or less were used. For example, 18650 and 21700 batteries were previously used. In the case of an 18650 battery, its diameter is approximately 18 mm, its height is approximately 65 mm, and its form factor ratio is approximately 0.277. In the case of a 21700 battery, its diameter is approximately 21 mm, its height is approximately 70 mm, and its form factor ratio is approximately 0.300.

[0248] Reference Figure 29 The battery pack 3 of one embodiment of the present invention includes the cylindrical battery 1 of one embodiment of the present invention as described above. In the accompanying drawings of the present invention, components such as busbars, cooling units, and power terminals used for electrical connections are omitted for ease of illustration.

[0249] Reference Figure 30 In one embodiment of the present invention, the vehicle 5 is, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, including a battery pack 3 according to one embodiment of the present invention. The vehicle 5 includes both four-wheeled and two-wheeled vehicles. The vehicle 5 operates by receiving power from the battery pack 3 according to one embodiment of the present invention.

[0250] The following describes an example of the anode active material used in the cylindrical battery of the present invention.

[0251] In this embodiment, "primary particle" refers to a particle unit that does not appear to have grain boundaries when observed using a scanning electron microscope or an electron backscattered electron rotation pattern analyzer (EBSD) at a field of view of 5000x to 20000x. "Average particle size of primary particles" refers to the arithmetic mean of the primary particles observed in the scanning electron microscope or EBSD images, calculated after measuring their particle sizes.

[0252] "Secondary particles" are particles formed by the condensation of multiple primary particles. In this invention, in order to distinguish them from conventional secondary particles formed by the condensation of dozens to hundreds of primary particles, secondary particles formed by the condensation of fewer than 10 primary particles are referred to as similar-single particles.

[0253] In this invention, the "specific surface area" is detected by the BET method, specifically calculated by the amount of nitrogen gas adsorbed at liquid nitrogen temperature (77K) using BELSORP-mino II from BEL Japan.

[0254] In this invention, "D" min “D” 50 "and "D max"D" is the particle size value of the volumetric cumulative distribution of anolyte active material, detected using the laser diffraction method. Specifically, D min D is the smallest particle size represented in the volumetric cumulative distribution. 50 It is the particle size when the volume accumulation is 50%, D max It represents the maximum particle size shown in the volumetric cumulative distribution. In the case of a single particle of the anolyte, D... 50 This refers to the average particle size of primary particles. Additionally, in the case of anode active materials that are similar to single particles, D... 50 It refers to the average particle size of particles formed by a single particle aggregation.

[0255] Regarding the particle size value of the aforementioned volumetric cumulative distribution, for example, the anolyte is dispersed in a dispersion medium and then introduced into a commercially available laser diffraction particle size analyzer (e.g., MicrotracMT 3000) and irradiated with 28kHz ultrasound at an output of 60W to obtain a volumetric cumulative particle size distribution curve for detection.

[0256] In this invention, "consist essentially of A" means including component A and any unmentioned unmentioned components that do not materially affect the fundamental and novel features of the invention. The fundamental and novel features of the invention include at least one of minimizing particle breakage during battery manufacturing, minimizing gas generation resulting from such particle breakage, and minimizing the occurrence of internal cracks. Those skilled in the art will understand the material effects of such properties.

[0257] The inventors have conducted repeated research in order to develop an anode for an electrochemical element that exhibits high capacity and excellent safety, and an electrochemical element including the anode. The results show that when using an anode active material consisting of a single particle composed of one primary particle or a condensation of 10 or fewer primary particles, i.e., a single-particle-like morphology, as the anode active material, the safety of large cylindrical batteries can be significantly improved.

[0258] According to one side, the anode includes an anode current collector; and an anode active material layer formed on at least one side of the anode current collector, the anode active material layer including an anode active material, selectively including a conductive material and / or an adhesive.

[0259] The anode is a structure in which an anode active material layer is formed on at least one or two sides of an elongated sheet-shaped anode current collector, wherein the anode active material layer includes an anode active material and an adhesive.

[0260] Specifically, the aforementioned anode is manufactured by coating one or both sides of an elongated sheet-shaped anode current collector with an anode solder in which the anode active material, conductive material, and binder are dispersed in solvents such as dimethyl sulfoxide (DMSO), isopropanol, N-methylpyrrolidone (NMP), acetone, or water. The solvent in the anode solder is removed through a drying process, and then it is obtained by calendering. On the other hand, an anode including an uncoated portion (uncoated portion) is manufactured by leaving a portion of the anode current collector uncoated during the coating process, such as one end of the anode current collector.

[0261] In another aspect, the aforementioned anodic active material comprises single-particle-based active material particles. In one embodiment, relative to 100 wt% of the aforementioned anodic active material, the single-particle-based active material particles are 90 wt% or more, 95 wt% or more, 98 wt% or more, or 99 wt% or more. In a specific embodiment, the aforementioned anodic active material is composed solely of the aforementioned single-particle-based active material particles.

[0262] In this specification, the aforementioned single-particle-based active material particles include single particles, similar single particles, or both. The aforementioned single particle is a particle consisting of one primary particle, and the aforementioned similar-single particle is an aggregate of 10 or fewer primary particles.

[0263] Traditionally, spherical secondary particles consisting of tens to hundreds of primary particles aggregated together are typically used as the anode active material in lithium-ion batteries. However, in the case of anode active materials with such a secondary particle form composed of numerous primary particles, particle breakage due to primary particle detachment is prone to occur during the rolling process in anode manufacturing, and internal cracks can develop within the particles during charge and discharge. With particle breakage or internal cracks in the anode active material, the contact area with the electrolyte increases, thus increasing gas generation through side reactions with the electrolyte. This increase in gas generation inside a cylindrical battery leads to increased internal pressure, posing a risk of battery explosion. In particular, increasing the volume of a cylindrical battery increases the mass of active material inside, significantly increasing gas generation and thus increasing the risk of fire and / or explosion.

[0264] In contrast, single-particle-based active material particles, consisting of a single primary particle or an agglomeration of fewer than 10 primary particles, exhibit higher particle strength compared to conventional secondary-particle-based anodic active materials that agglomerate dozens to hundreds of primary particles. Therefore, particle breakage is almost nonexistent during calendering. Furthermore, in the case of single-particle-based active material particles, the fewer primary particles constituting the particle result in smaller changes in volume due to expansion and contraction of the primary particles during charging and discharging, thereby significantly reducing internal cracks within the particles.

[0265] Therefore, when using single-particle-based active material particles as in this invention, the amount of gas generated due to particle breakage and internal cracks can be significantly reduced. This results in excellent safety when applied to large cylindrical batteries.

[0266] On the other hand, based on the weight of all anodic active material included in the anode, the content of the above-mentioned single particles and / or similar single particles is preferably 95 wt% to 100 wt%, preferably 98 wt% to 100 wt%, more preferably 99 wt% to 100 wt%, and even more preferably 100 wt%.

[0267] When the content of single particles and / or similar single particles meets the above range, sufficient safety can be obtained when applied to large batteries. Because when the content of secondary particle-form anolyte in the total anolyte exceeds 5 wt%, during electrode manufacturing and charge / discharge, the gas generation suppression effect decreases due to increased side reactions between the derivatives of secondary particles and the electrolyte, thus reducing the safety improvement effect when applied to large batteries.

[0268] On the other hand, the present invention includes anode active materials comprising single particles and / or similar single particles. min The micrometer size is 1.0 μm or larger, 1.1 μm or larger, 1.15 μm or larger, 1.2 μm or larger, 1.25 μm or larger, 1.3 μm or larger, or 1.5 μm or larger. The D of the anolyte active material... min When the particle size is less than 1.0 μm, the increased linear pressure during the anodic calendering process can easily cause particle breakage, resulting in decreased thermal safety. Therefore, thermal safety cannot be adequately ensured when applied to large cylindrical batteries.

[0269] On the other hand, considering resistance and power characteristics, the D of the aforementioned anode active material min The value is below 3μm, below 2.5μm, or below 2μm. If D min If the value is too large, the diffusion distance of lithium ions within the particles increases, which leads to a decrease in resistance and power characteristics.

[0270] For example, the D of the above-mentioned anodic active materialmin The range is 1.0 μm to 3 μm, 1.0 μm to 2.5 μm, or 1.3 μm to 2.0 μm.

[0271] On the other hand, the D of the above-mentioned anodic active material 50 The size is 5 μm or less, 4 μm or less, or 3 μm or less, for example, 0.5 μm to 5 μm, preferably 1 μm to 5 μm, and more preferably 2 μm to 5 μm.

[0272] Single-particle and / or similar single-particle morphologies of anode active materials have fewer interfaces between primary particles that form the diffusion path for lithium ions within the particle itself. Therefore, compared to secondary-particle morphologies of anode active materials, lithium mobility is reduced, leading to increased resistance. The larger the particle size, the greater this increase in resistance, which adversely affects capacity and power characteristics. Therefore, increasing the D of the anode active material... 50 By adjusting the diameter to below 5μm, the diffusion distance of lithium ions inside the anode active material particles is minimized, thereby suppressing the increase in resistance.

[0273] In addition, the D of the above-mentioned anodic active material max The diameter is 12 μm to 17 μm, preferably 12 μm to 16 μm, and more preferably 12 μm to 15 μm. The D of the anode active material... max When the above range is met, the resistance and capacitance characteristics are even better. The D of the anode active material... max When the density is too high, aggregation occurs between individual particles. The lithium migration path within these aggregated particles becomes longer, leading to decreased lithium mobility and thus increased resistance. On the other hand, the D of the anode active material... max If the size is too small, it leads to excessive crushing, which in turn causes D to... min If the particle size is less than 1 μm, the particles will break during calendering, resulting in a decrease in thermal safety.

[0274] On the other hand, the particle size distribution (PSD) of the anodic active material represented by the following formula 1 is 3 or less, preferably 2 to 3, and more preferably 2.3 to 3.

[0275] Equation (1): Particle size distribution (PSD) = (D max -D min ) / D 50

[0276] When the anolyte has the particle size distribution described above, the electrode density of the anolyte can be maintained appropriately, effectively suppressing particle breakage and resistance increase.

[0277] On the other hand, the average particle size of the primary particles in the aforementioned anodic active material is 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less, for example, 0.5 μm to 5 μm, preferably 1 μm to 5 μm, and more preferably 2 μm to 5 μm. When the average particle size of the primary particles meets the above range, it is possible to form an anodic active material with excellent electrochemical properties in the form of single particles and / or similar single-particle morphologies. If the average particle size of the primary particles is too small, the number of primary particles agglomerated to form the anodic active material increases, and the effect of suppressing particle breakage during calendering decreases. If the average particle size of the primary particles is too large, the lithium diffusion path inside the primary particles becomes longer, the resistance increases, and the power characteristics decrease.

[0278] In this invention, the aforementioned anode active material preferably has a unimodal particle size distribution. Conventionally, to increase the electrode density of the anode active material layer, bimodal anode active materials, which are mixtures of large-particle-size anode active materials with a large average particle size and small-particle-size anode active materials with a small average particle size, are typically used. However, in the case of anode active materials with single-particle or similar single-particle morphology, as the particle size increases, the lithium migration path becomes longer, and the resistance increases significantly. Therefore, when using a mixture of large-particle materials, this leads to a decrease in capacity and power characteristics. Therefore, in this invention, an anode active material with a unimodal distribution is used, thereby minimizing the increase in resistance.

[0279] On the other hand, the aforementioned anode active material includes lithium nickel oxides. Specifically, based on the total molar amount of the transfer metal, it may include lithium nickel oxides containing 80 mol% or more of Ni. Preferably, the aforementioned lithium nickel oxides contain 80 mol% or more but less than 100 mol% Ni, 82 mol% or more but less than 100 mol% Ni, or 83 mol% or more but less than 100 mol% Ni. When using lithium nickel oxides with a higher Ni content as described above, a higher capacity can be achieved.

[0280] More specifically, the aforementioned anodic active material includes lithium nickel oxides represented by [Chemical Formula 1] below.

[0281] [Chemical Formula 1]

[0282] Li a Ni b Co c M 1 d M 2 e O2

[0283] In the above chemical formula 1, M 1 It is Mn, Al, or a combination thereof, preferably Mn or Mn and Al.

[0284] The above-mentioned M 2 is one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb, preferably one or more selected from the group consisting of Zr, Y, Mg, and Ti, and more preferably Zr, Y, or a combination thereof. M 2 is not an essential element, but when included in an appropriate amount, it promotes particle growth during plastic processing or performs the function of improving the safety of the crystal structure.

[0285] The above-mentioned a represents the molar ratio of lithium in the lithium nickel-based oxide, 0.8 ≤ a ≤ 1.2, 0.85 ≤ a ≤ 1.15, or 0.9 ≤ a ≤ 1.2. When the molar ratio of lithium satisfies the above range, the crystal structure of the lithium nickel-based oxide is stably formed.

[0286] The above-mentioned b represents the molar ratio of nickel in all metals other than lithium in the lithium nickel-based oxide, 0.8 ≤ b < 1, 0.82 ≤ b < 1, 0.83 ≤ b < 1, 0.85 ≤ b < 1, 0.88 ≤ b < 1, or 0.90 ≤ b < 1. When the molar ratio of nickel satisfies the above range, a high energy density is exhibited and a high capacity can be realized.

[0287] The above-mentioned c represents the molar ratio of cobalt in all metals other than lithium in the lithium nickel-based oxide, 0 < c < 0.2, 0 < c < 0.18, 0.01 ≤ c ≤ 0.17, 0.01 ≤ c ≤ 0.15, 0.01 ≤ c ≤ 0.12, or 0.01 ≤ c ≤ 0.10. When the molar ratio of cobalt satisfies the above range, good resistance characteristics and power characteristics can be realized.

[0288] The above-mentioned d represents the molar ratio of the M 1 element in all metals other than lithium in the lithium nickel-based oxide, 0 < d < 0.2, 0 < d < 0.18, 0.01 ≤ d ≤ 0.17, 0.01 ≤ d ≤ 0.15, 0.01 ≤ d ≤ 0.12, or 0.01 ≤ d ≤ 0.10. M 1 When the molar ratio of the element satisfies the above range, the structural safety of the anode active material is excellent.

[0289] The above-mentioned e represents the molar ratio of the M 2 element in all metals other than lithium in the lithium nickel-based oxide, 0 ≤ e ≤ 0.1, or 0 ≤ e ≤ 0.05.

[0290] On the other hand, as needed, the anolyte of the present invention further includes a coating on the surface of the aforementioned lithium nickel oxide particles. This coating comprises one or more coating elements selected from the group consisting of Al, Ti, W, B, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si, and S. Preferably, the coating element is Al, B, Co, or a combination thereof.

[0291] When a coating is present on the surface of lithium nickel oxide particles, the contact between the electrolyte and the lithium nickel oxide is suppressed by the coating, thereby reducing the amount of transferred metal melting or gas generation caused by side reactions with the electrolyte.

[0292] The anolyte comprises 80 wt% to 99 wt% relative to the total weight of the anolyte layer, preferably 85 wt% to 99 wt%, and more preferably 90 wt% to 99 wt%.

[0293] On the other hand, various anode current collectors used in this technical field can be used as the aforementioned anode current collector. For example, stainless steel, aluminum, nickel, titanium, plastic carbon, or aluminum or stainless steel surfaces treated with carbon, nickel, titanium, silver, etc., can be used as the aforementioned anode current collector. The aforementioned anode current collector typically has a thickness of 3 μm to 500 μm, and fine irregularities are formed on the surface of the aforementioned anode current collector to improve the adhesion of the anode active material. The aforementioned anode current collector is used in various forms, such as thin films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0294] On the other hand, in one embodiment of the present invention, all or part of the aforementioned single-particle-based active material particles possess a core-shell structure with the particle surface covered by a conductive coating. The conductive coating may cover at least a portion or all of the particles. The conductive coating comprises conductive nanomaterials.

[0295] In the case of the aforementioned single-particle-based active material particles, compared to conventional secondary-particle anolyte active materials, the resistance is higher and the contact area with the conductive material is smaller, resulting in a decrease in conductivity. To improve conductivity, when an excessive amount of conductive material is added, agglomeration occurs within the anolyte, increasing viscosity and thus reducing coatability. Therefore, to achieve smooth coatability, it is necessary to reduce the solid powder content and lower the viscosity of the anolyte. However, when the solid powder content in the anolyte is reduced, the active material content decreases, leading to a decrease in capacity characteristics. To solve this problem, this invention uses conductive nanomaterials to coat the surface of the single-particle-based active material particles, thereby achieving excellent conductivity even without adding additional conductive materials to the anolyte.

[0296] In one embodiment of the present invention, when an anodic active material is applied to the surface of the aforementioned single-particle-based active material particles coated with conductive nanomaterials, the portion of the anodic active material layer other than the conductive coating may use a conductive material. This eliminates the need for additional conductive materials that cause anode solder aggregation, thus reducing the viscosity of the anode solder, increasing the solid powder content, and improving electrode coating processability and electrode adhesion.

[0297] In this invention, the aforementioned conductive nanomaterials have a nanoscale size to facilitate coating onto particles, and any conductive material is acceptable, without particular limitation on its type. For example, the aforementioned conductive nanomaterials are carbon nanotubes, carbon nanoparticles, etc.

[0298] The aforementioned conductive nanomaterials can take various forms, such as spherical, scaly, or fibrous shapes.

[0299] On the other hand, the aforementioned conductive coating is formed by heat treatment after mixing the core, i.e., single-particle-based active material particles, with conductive nanomaterials. In this case, the mixing is either solid-state mixing or liquid-state mixing.

[0300] In one embodiment of the present invention, the aforementioned anode active material layer comprises flake-like graphite. When the aforementioned single-particle-based active material is used as the anode active material, and the anode active material layer comprises flake-like graphite, during the rolling of the anode active material layer, the flake-like graphite provides a sliding effect to the anode active material, thereby improving the rolling characteristics of the electrode and reducing the electrode porosity to the target level. Thus, batteries using the anode of the present invention can improve safety, initial resistance characteristics, and charge / discharge efficiency.

[0301] In one embodiment of the present invention, relative to 100 wt% of the above-mentioned anodic active material layer, it includes 0.1 wt% to 5 wt% of the above-mentioned flake graphite, preferably including 0.1 wt% to 3 wt% of 0.1 wt% to 5 wt%.

[0302] When the content of flake graphite meets the above range, it improves the anodic calendering characteristics and exhibits excellent electrode density. If the content of flake graphite is too low, the improvement in calendering characteristics is weak; if it is too high, it leads to an increase in slurry viscosity and a decrease in phase safety. Through bonding with conductive materials, the resistance can increase due to a decrease in electrode uniformity.

[0303] On the other hand, the average particle size of the flake graphite used in this invention is 1 μm to 20 μm, preferably 2 μm to 10 μm, more preferably 3 μm to 5 μm, but not limited thereto. If the size of the flake graphite is too small, it is difficult to achieve the desired porosity, reducing the current density and thus causing a decrease in capacity. In this case, the average particle size of the flake graphite is detected by laser diffraction (ISO 13320).

[0304] Furthermore, the aspect ratio of the aforementioned flake graphite is from 0.1 to 500, preferably from 1 to 100, and more preferably from 1 to 30. When the aspect ratio of the flake graphite meets the above range, the conductivity is improved, thereby achieving the effect of reducing electrode resistance.

[0305] In addition, the density of the aforementioned flake graphite is 2.0 g / cm³. 3 Up to 2.5g / cm 3 The preferred value is 2.1 g / cm³. 3 Up to 2.4 g / cm 3 More preferably 2.2 g / cm³ 3 Up to 2.3 g / cm 3 .

[0306] On the other hand, in this invention, the porosity of the aforementioned anode active material layer is 15% to 23%, preferably 17% to 23%, and more preferably 18% to 23%. When the porosity of the anode active material layer meets the above range, the electrode density increases, resulting in excellent capacity and reduced resistance. If the porosity is too low, the electrolyte impregnation decreases, and lithium deposition occurs due to lack of electrolyte impregnation. If it is too high, the contact between the electrodes is poor, the resistance increases, the energy density decreases, and thus the capacity improvement effect is weak.

[0307] The porosity value of the aforementioned anodic active material layer is achieved by i) the aforementioned anodic active material includes single-particle-based active material particles; and ii) the addition of flake graphite to the aforementioned anodic active material.

[0308] When a high-load electrode with a relatively high loading of the anode active material layer is used, such as in the present invention, when a single-particle or similar single-particle morphology anode active material is used, compared with conventional secondary particle morphology anode active materials, the particle breakage of the active material during calendering is significantly reduced, and the damage to the anode current collector (Al Foil) is reduced. Therefore, calendering can be performed at a relatively high line voltage, thereby reducing the porosity of the anode active material layer to the value range mentioned above and increasing the energy density.

[0309] Furthermore, as in the present invention, when the anode active material layer includes flake graphite, the flake graphite enhances the sliding effect during calendering and can fill the voids in the anode active material layer, thereby reducing the porosity of the anode active material layer to the range described above.

[0310] In addition, the loading of the above-mentioned anode is 570 mg / 25 cm. 2 The above is preferably 600mg / 25cm 2 Up to 800g / 25m 2 More preferably 600mg / 25cm 2 Up to 750mg / 25cm 2 Specifically, in the case of the lithium secondary battery of the present invention, single-particle and / or similar single-particle anode active materials and flake graphite are used to improve the rolling characteristics of the electrode, thereby ensuring a higher level of anode loading and thus exhibiting high capacity characteristics.

[0311] In one embodiment of the present invention, the aforementioned anode active material layer further includes a conductive material. The conductive material is used to impart conductivity to the electrode, and can be used arbitrarily as long as it does not cause a chemical change within the battery and possesses electronic conductivity. Specific examples include natural graphite, artificial graphite, etc.; carbon black, acetylene black, Kelvin black, channel black, furnace black, lampblack, carbon black, carbon fiber, carbon nanotubes, and other carbonaceous materials; metal powders or fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polystyrene derivatives. One of these materials can be used alone or in a mixture of two or more. Typically, the content of the conductive material relative to the total weight of the anode active material layer is 1 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1 wt% to 10 wt%.

[0312] In one specific embodiment of the present invention, the conductive material includes carbon nanotubes.

[0313] In one embodiment of the present invention, the anolyte, as a conductive material, comprises multi-walled carbon nanotubes with a high specific surface area and a low wall number. In 100 wt% of the conductive material, it comprises 50 wt% or more, 70 wt% or more, 90 wt% or more, or 99 wt% or more of the aforementioned multi-walled carbon nanotubes. In a specific embodiment of the present invention, the conductive material is composed solely of the aforementioned multi-walled carbon nanotubes.

[0314] In this invention, the BET specific surface area of ​​the aforementioned multi-walled carbon nanotubes is 300 m². 2 / g to 500m 2 / g. To distinguish this from previous technologies, it is called 'new CNT'.

[0315] Previously, the BET specific surface area of ​​carbon nanotubes (existing CNTs) used under normal circumstances was less than 300 m². 2 / g. The novel CNT used in this invention ( Figure 31 ) and existing CNT ( Figure 32 Compared with scanning electron microscope images and physical properties () Figure 33 The results are as follows.

[0316] As can be seen from the above SEM images, the novel CNTs used in this invention are of the bundled type, forming a multiwall structure. However, compared with existing CNTs, the BET is high, and the number and diameter of the walls are small.

[0317] When using secondary particle anolyte materials, sufficient conductivity can be achieved even when using existing CNTs at levels of 0.4wt% to 0.6wt%. However, with single-particle or similar single-particle anolyte materials, the resistance is higher and the contact area with the conductive material is smaller compared to conventional secondary particle anolyte materials, resulting in decreased conductivity. Therefore, a BET specific surface area of ​​less than 300m² is required. 2 For existing CNTs of / g, the conductive material content should be above 0.9wt% to demonstrate sufficient conductivity.

[0318] Figures 34 to 37 It is a graph showing the sheet resistance and high-temperature lifetime characteristics of conductive materials at various ratios when used as single-particle or similar single-particle anode active materials.

[0319] Based on the above graphs, when using single-particle or similar single-particle anode active materials, the amount of conductive material required needs to be increased compared to the case where anode active materials with a secondary particle form are used.

[0320] However, when the carbon nanotube content increases to above 0.9 wt%, agglomeration occurs within the anolyte, increasing viscosity and thus reducing coatability. Therefore, to achieve good coatability, it is necessary to reduce the solid powder content in the anolyte to lower its viscosity. However, if the solid powder content in the anolyte is reduced, the active material content decreases, leading to a decline in capacity characteristics.

[0321] To solve this problem, the inventors conducted continuous research, and the results confirmed that when used together with single-particle-based active material particles, i.e., anolytical active material, as a conductive material, the applicable BET specific surface area is 300 m². 2 / g to 500m 2With a carbon nanotube content of / g, conductivity can be adequately ensured with only a relatively small amount of carbon nanotubes. Thus, even if the solid powder content of the anode solder is increased to 70wt% to 80wt%, the slurry viscosity can be kept low.

[0322] Specifically, the carbon nanotubes used in this invention have a BET specific surface area of ​​300 m². 2 / g to 500m 2 / g, preferably 300m 2 / g to 450m 2 / g of multi-walled carbon nanotubes. Sufficient conductivity can be ensured even with a small amount of carbon nanotubes when the BET specific surface area meets the above range.

[0323] In addition, the carbon nanotubes mentioned above are multi-walled carbon nanotubes with a wall number of 2 to 8, preferably 2 to 6, and more preferably 3 to 6.

[0324] In addition, the diameter of the carbon nanotubes is 1 nm to 8 nm, preferably 3 nm to 8 nm, and more preferably 3 nm to 6 nm.

[0325] The content of carbon nanotubes relative to the total weight of the anodic active material layer is 0.7 wt% or less, preferably 0.3 wt% to 0.7 wt%, and more preferably 0.4 wt% to 0.6 wt%. When the carbon nanotube content meets the above range, sufficient conductivity can be achieved, and the solid powder content in the anodic solder is maintained at a high level. This allows for the formation of a high content of anodic active material within the anodic active material layer, thereby exhibiting excellent capacity characteristics.

[0326] Figure 38 The table shown in the diagram indicates that the applicable BET specific surface area is 300m². 2 / g to 500m 2 / g of carbon nanotubes (novel CNTs) and applicable BET of 200m 2 / g or more and less than 300m 2 A comparison was made of the solid powder content and viscosity of the anode solder, as well as the resistivity of the MP coating and MP interface layer, in the case of / g carbon nanotubes (existing CNTs). The table above shows that, when using the new CNTs, the anode solder exhibits lower viscosity and superior conductivity even with a higher solid powder content compared to existing CNTs.

[0327] The aforementioned adhesive enhances the adhesion between anolyte particles and the bonding strength between the anolyte and the anode current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyvinyl fluoride, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM) rubber, sulfonated EPDM, styrene-butadiene rubber (SBR), fluorinated rubber, or various copolymers thereof. One of these adhesives may be used alone or in mixtures of two or more. The adhesive comprises, but is preferred, 1 wt% to 30 wt% of the total weight of the anolyte layer, and more preferably 1 wt% to 10 wt%.

[0328] Another aspect of the present invention relates to an electrode assembly including the aforementioned anode and a battery including the same. The electrode assembly includes a cathode and an anode, wherein the anode has the structural features described above.

[0329] The aforementioned electrode assembly, for example, is formed by stacking separation membranes in a state sandwiched between the cathode and anode to form a stacked or stacked / folded structure, or by rolling them up to form a gel roll structure. Furthermore, when forming the gel roll structure, a separation membrane is additionally disposed on the outer side to prevent the cathode and anode from contacting each other.

[0330] The cathode includes a cathode current collector and a cathode active material layer formed on at least one side of the cathode current collector. The cathode is formed with a cathode active material layer formed on one or both sides of the elongated sheet-like cathode current collector, the cathode active material layer including cathode active material, conductive material and adhesive.

[0331] Specifically, the aforementioned cathode is prepared by coating one or both sides of a long, sheet-shaped cathode current collector with a cathode paste made by dispersing cathode active material, conductive material, and binder in solvents such as dimethyl sulfoxide (DMSO), isopropanol, N-methylpyrrolidone (NMP), acetone, and water. The solvent in the cathode paste is removed through a drying process, and then the cathode is produced by calendering. Alternatively, when coating the cathode paste, a cathode including an uncoated portion can be manufactured by leaving a portion of the cathode current collector, such as one end of the cathode current collector, uncoated.

[0332] As the above-mentioned cathode active material, a compound capable of achieving reversible insertion and extraction of lithium can be used. Specific examples of the cathode active material include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon, Si, Si-Me alloy (where Me is one or more selected from the group consisting of Al, Sn, Mg, Cu, Fe, Pb, Zn, Mn, Cr, Ti, and Ni), SiO y (where 0 < y < 2), silicon-based substances such as Si-C composites, lithium metal thin films, metal substances such as Sn and Al that can be alloyed with lithium, etc. Any one or a mixture of two or more of them can be used.

[0333] In the present invention, the above-mentioned cathode includes a silicon-based cathode active material. The above-mentioned silicon-based cathode active material can be Si, Si-Me alloy (where Me is one or more selected from the group consisting of Al, Sn, Mg, Cu, Fe, Pb, Zn, Mn, Cr, Ti, and Ni), SiO y (where 0 < y < 2), Si-C composite or a combination thereof, preferably SiO y (where 0 < y < 2). The silicon-based cathode active material has a high theoretical capacity. Therefore, when including the silicon-based cathode active material, the capacity characteristics can be improved.

[0334] The above-mentioned silicon-based cathode active material is formed by doping with Mb metal. At this time, the above-mentioned Mb metal is a Group 1 metal element or a Group 2 metal element. Specifically, it can be Li, Mg, etc. Specifically, the above-mentioned silicon cathode active material is doped with Si, SiO y (where 0 < y < 2), Si-C composite, etc. In the case of the metal-doped silicon-based cathode active material, due to the doping element, the active material capacity will decrease somewhat, but because it has a high efficiency, a high energy density can be exhibited.

[0335] Figure 55 It is a graph showing the change in energy density in a battery using a mixture of a silicon-based cathode active material and a carbon-based cathode active material as the cathode active material, according to the content of the silicon-based cathode active material and the presence or absence of doping of the silicon-based cathode active material.

[0336] Figure 55 In the figure, Low efficiency SiO refers to undoped SiO, and Ultra-High efficiency SiO refers to SiO doped with Mg / Li. By Figure 55 It can be seen that in the entire cathode active material, the higher the content of the silicon-based cathode active material, the higher the energy density. In addition, the higher the ratio of the doped silicon-based cathode active material in the silicon-based cathode active material, the more excellent the improvement effect of the energy density.

[0337] The aforementioned silicon-based cathode active material also includes a carbon coating on the particle surface. In this case, based on the total weight of the silicon-based cathode active material, the carbon coating amount is 20 wt% or less, preferably 1 to 20 wt%. The carbon coating is formed by methods such as dry coating, wet coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer evaporation (ALD).

[0338] In one embodiment of the present invention, the silicon-based cathode active material has a capacity of 1000 to 4000 mAh / g and an initial efficiency of 60 to 95%.

[0339] In yet another embodiment of the present invention, the D of the above-mentioned silicon-based cathode active material... 50 The range is from 3um to 8um, D min ~D max The range is from 0.5um to 30um.

[0340] Depending on the requirements, the aforementioned cathode may also include carbon-based cathode active materials as cathode active materials. Examples of such carbon-based cathode active materials include, but are not limited to, artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, soft carbon, and hard carbon.

[0341] When a mixture of silicon-based cathode active material and carbon-based cathode active material is used as the cathode active material, the mixing ratio of the silicon-based cathode active material and the carbon-based cathode active material by weight is 1:99 to 20:80, preferably 1:99 to 15:85, and more preferably 1:99 to 10:90.

[0342] The cathode active material contained in the cathode active material layer is 80 wt% to 99 wt%, preferably 85 wt% to 99 wt%, and more preferably 90 wt% to 99 wt%, relative to the total weight of the cathode active material layer.

[0343] Depending on the requirements, the aforementioned cathode active materials may also include lithium metal and one or more metals such as Sn and Al that can be alloyed with lithium.

[0344] As the aforementioned cathode current collector, cathode current collectors commonly used in this technical field can be used, such as copper, stainless steel, aluminum, nickel, titanium, plastic-processed carbon, products of surface treatment of copper or stainless steel with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloys. These cathode current collectors typically have a thickness of 3 μm to 500 μm, and similar to anode current collectors, fine irregularities can be formed on the surface of the current collector to enhance the bonding force of the cathode active material. For example, the cathode current collector can be used in various forms such as thin films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0345] The aforementioned conductive materials are used to impart conductivity to the cathode. Any material can be used as long as it does not cause a chemical change within the battery and possesses electronic conductivity. Specific examples of conductive materials include natural or artificial graphite, carbon black, acetylene black, kerosene black, channel black, furnace black, lampblack, carbon fiber, carbon nanotubes, and other carbonaceous materials; metal powders or fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive polymers such as polystyrene derivatives. One of these materials can be used alone or in mixtures of two or more. Typically, the amount of the aforementioned conductive material contained in the cathode active material layer is 1 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1 wt% to 10 wt%.

[0346] The aforementioned adhesive enhances the adhesion between cathode active material particles and the bonding strength between the cathode active material and the cathode current collector. Specific examples of adhesives include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyvinyl fluoride, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM) rubber, sulfonated EPDM, styrene-butadiene rubber (SBR), fluorinated rubber, or various copolymers thereof. One of these adhesives may be used alone or in mixtures of two or more. The amount of the aforementioned adhesive included relative to the total weight of the cathode active material layer is 1 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1 wt% to 10 wt%.

[0347] The electrode assembly also includes a separation membrane disposed within the electrode assembly, sandwiched between the cathode and the anode. This separation membrane separates the cathode and anode to provide a pathway for lithium ion movement; it can be used in any manner suitable for use as a separator in lithium batteries.

[0348] As the aforementioned separation membrane, porous polymer films can be used, such as porous polymer films made of polyolefin polymers, like ethylene monomer polymers, propylene monomer polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers, or laminated structures of two or more layers thereof. Nonwoven fabrics made of common porous nonwoven fabrics, such as high-melting-point glass fibers or polyethylene terephthalate fibers, can also be used. Furthermore, separation membranes comprising and coated with ceramic components or polymeric substances are used to ensure heat resistance or mechanical strength.

[0349] Another aspect of the present invention relates to a battery including the aforementioned electrode assembly. The battery houses the electrode assembly and electrolyte together in a battery casing. As the battery casing, any casing commonly used in the art, such as a pouch type or a metal casing, can be appropriately selected.

[0350] The electrolyte used in this invention can be any type of electrolyte that can be used in lithium batteries, such as organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., and there is no particular limitation on its type.

[0351] Specifically, the electrolytes mentioned above include organic solvents and lithium salts.

[0352] As the aforementioned organic solvent, any solvent capable of acting as a medium for the movement of ions participating in the electrochemical reactions of the battery can be used. Specifically, as the aforementioned organic solvent, ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone can be used; ether solvents such as dibutyl ether or tetrahydrofuran can be used; ketone solvents such as cyclohexanone can be used; and benzene and fluorobenzene can also be used. Aromatic hydrocarbon solvents such as ne, dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylenecarbonate (EC), propylene carbonate (PC) and other carbonate solvents, ethyl alcohol, isopropanol and other alcohol solvents, butyronitrile solvents such as R-CN (R is a C2 to C20 straight-chain, branched or cyclic hydrocarbon group, including double-linked directional rings or ether linkages), amides such as dimethylformamide, dioxolane such as 1,3-dioxolane or sulfolane, etc. Preferably, carbonate solvents are used, and more preferably, a mixture of cyclic carbonates (such as ethylene carbonate or propylene carbonate) with high ionic conductivity and inherent conductivity, which can improve the charge and discharge performance of the battery, and low-viscosity linear carbonate compounds (such as methyl ethyl carbonate, dimethyl carbonate, or diethyl carbonate).

[0353] Regarding the aforementioned lithium salt, any compound capable of providing lithium ions for use in lithium batteries can be used. Specifically, LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2 can be used. The concentration of the aforementioned lithium salt is from 0.1M to 5M, preferably from 0.1M to 3.0M. When the concentration of the lithium salt is within the above range, the electrolyte exhibits appropriate conductivity and viscosity, thus demonstrating excellent electrolyte performance and enabling efficient movement of lithium ions.

[0354] In addition to the aforementioned electrolyte structural components, the electrolyte further includes additives to improve battery life characteristics, suppress battery capacity reduction, and increase battery discharge capacity. For example, additives may be used alone or in combination with other compounds such as halogenated hydrocarbon carbonates like difluoroethylene carbonate, pyridine, triethyl phosphide, triethanolamine, cyclic ethers, ethylenediamine, N-glycol dimethyl ether (glyme), hexamethylphosphoric triamine, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolides, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-ethylene glycol monomethyl ether, or aluminum trichloride, but are not limited to these. The content of the additives relative to the total weight of the electrolyte is 0.1 wt% to 10 wt%, preferably 0.1 wt% to 5 wt%.

[0355] In another embodiment of the invention, the anode includes a load-reducing section with a smaller loading of anode active material than that in adjacent regions. When the anode has this structure, there is no need to worry about lithium deposition, and the area of ​​the anode active material section can be increased. This, in turn, improves the energy density of the electrode assembly.

[0356] In recent years, research has focused on increasing battery size to achieve higher energy density and lower costs. As battery size increases, the resistance of each cell needs to be reduced. To reduce resistance, instead of attaching electrode tabs to the electrodes, the current collector of the electrodes is used as the electrode tab. However, in the electrode manufacturing process where electrode paste is coated onto the current collector, a decrease in load occurs at the boundary between the cathode active material and the cathode current collector. Considering N / Pratio, lithium metal may deposit in the anode active material, opposite to the area with reduced load. Here, N / Pratio is the value of the cathode capacity (calculated considering the cathode area and capacity per mass) divided by the anode capacity (calculated considering the anode area and capacity per mass), and generally has a value of 1 or higher. That is, a higher cathode capacity can be manufactured. For reference, when N / Pratio is less than 1, lithium metal is easily deposited during charging and discharging, which can drastically degrade battery safety during efficient charging and discharging. In other words, the N / Pratio has a significant impact on battery safety and capacity. As mentioned above, due to concerns about lithium metal deposition, the anode active material portion cannot be provided in the anode portion opposite to the portion where the cathode load is reduced. This is a reason why the battery's energy density cannot be improved. To address this, the present invention improves energy density by increasing the area of ​​the anode active material portion.

[0357] Figure 43 This is a diagram illustrating an electrode assembly according to an embodiment of the present invention. Figure 44 It shows along Figure 43The cross-sectional view of the section cut by the cutting line A-A'.

[0358] Reference Figure 43 and Figure 44 An embodiment of the electrode assembly 300 of the present invention includes a cathode 400, an anode 500, and a separation membrane 600. The separation membrane 600 is located between the cathode 400 and the anode 500. The cathode 400, the anode 500, and the separation membrane 600 are wound together to form a gel roll structure 300S. Here, the gel roll structure 300S refers to a structure formed by winding the cathode 400, the anode 500, and the separation membrane 600. Furthermore, when forming the gel roll structure 300S, to prevent the cathode 400 and the anode 500 from contacting each other, it is preferable to also provide the separation membrane 600 on the outer side.

[0359] The cathode 400 includes a cathode current collector 410 and a cathode active material portion 420 formed by coating the cathode current collector 410 with a cathode active material. Specifically, as shown in the figure, the cathode active material portion 420 is formed by coating both sides of the cathode current collector 410 with a cathode active material. Furthermore, an uncoated cathode portion 430, in the cathode current collector 410, extends in a first direction d1. The uncoated cathode portion 430 extends along one end of the wound cathode 400. Moreover, the uncoated cathode portion 430 extends further than the separation membrane 600 in the first direction d1. Thus, the uncoated cathode portion 430 is exposed at one end of the gel roll structure 300S in the first direction.

[0360] The anode 500 includes an anode current collector 510 and an anode active material portion 520 formed by coating the anode current collector 510 with an anode active material. Specifically, as shown in the figure, the anode active material portion 520 is formed by coating both sides of the anode current collector 510 with an anode active material. Furthermore, an uncoated anode portion 530 in the anode current collector 510, without an anode active material coating, extends in the second direction d2. The uncoated anode portion 530 extends along one end of the wound anode 500. Moreover, the uncoated anode portion 530 extends further than the separation membrane 600 in the second direction d2. Thus, the uncoated anode portion 530 is exposed at one end of the gel roll structure 300S in the second direction.

[0361] Here, the first direction d1 and the second direction d2 are directions opposite to each other. Furthermore, the first direction d1 and the second direction d2 are parallel to the height direction of the gel roll structure 300S.

[0362] In this embodiment, the electrode assembly 300 is not in the form of having additional electrode tabs attached. Instead, in order to reduce resistance, the cathode uncoated portion 430 of the cathode current collector 410 and the anode uncoated portion 530 of the anode current collector 510 are used as electrode tabs themselves.

[0363] Although not illustrated, the uncoated portion of the electrode described above has substantially the same structure as the uncoated portion of the electrode, including a cathode uncoated portion 430 and / or an anode uncoated portion 530.

[0364] In one embodiment, the anode active material section 520 includes a load reduction section 500D that has a smaller load of anode active material than that in adjacent regions, and the load reduction section 500D is located at one end of the anode 500 in a first direction d1. More specifically, the load of the anode active material gradually decreases as the load reduction section 500D approaches the first direction d1.

[0365] Here, loading refers to the amount of active material coated per unit area. In cases of higher loading, more cathode or anode active material is coated per unit area, resulting in a relatively thick cathode or anode active material portion. Conversely, in cases of lower loading, less cathode or anode active material is coated per unit area, resulting in a relatively thin cathode or anode active material portion.

[0366] An active material portion is formed by coating a slurry containing an active material, and in such a process, a boundary portion with gradually decreasing load is formed between the uncoated portion and the active material portion.

[0367] Specifically, the cathode active material portion 420 includes a cathode boundary portion 420B that forms the boundary between the cathode active material portion 420 and the cathode uncoated portion 430. The load on the cathode boundary portion 420B decreases as it approaches the cathode uncoated portion 430.

[0368] Similarly, the anode active material portion 520 includes an anode boundary portion 520B that forms the boundary between the anode active material portion 520 and the anode uncoated portion 530. The load on the anode boundary portion 520B decreases as it approaches the anode uncoated portion 530.

[0369] As described above, the cathode boundary 420B or anode boundary 520B with gradually decreasing load occurs naturally during the process of coating the slurry including the active material onto the cathode current collector 410 or anode current collector 510.

[0370] At this point, taking the direction perpendicular to the second direction d2 as a reference, in the region corresponding to the anode boundary 520B, the amount of anode active material is less than the amount of cathode active material. Since N / Pratio has a value greater than 1, problems such as lithium metal deposition will not occur.

[0371] The problem lies in the region corresponding to the cathode boundary 420B. Taking the direction perpendicular to the first direction d1 as a reference, in the region corresponding to the cathode boundary 420B, the amount of cathode active material is less than the amount of anode active material. At this time, the N / Pratio has a value less than 1, which may lead to the deposition of metallic lithium.

[0372] In this embodiment, a load reduction portion 500D is provided in the anode 500, and a cathode active material portion 420 is provided in the portion corresponding to the load reduction portion 500D, with the direction perpendicular to the first direction d1 as a reference. More specifically, a cathode boundary portion 420B is provided in the portion corresponding to the load reduction portion 500D, with the direction perpendicular to the first direction d1 as a reference.

[0373] A load-reducing portion 500D, with a smaller load of anolyte than the adjacent region, is provided at a position corresponding to the cathode boundary portion 420B where the load gradually decreases. This eliminates the need to increase the area coated with anolyte to prevent lithium deposition. Specifically, the cathode boundary portion 420B has a shape that corresponds to the gradual decrease in load as the load-reducing portion 500D approaches the first direction d1. Therefore, a higher N / Pratio relative to the cathode 400 and anode 500 can be maintained in the region where the cathode boundary portion 420B is formed, thereby preventing lithium deposition.

[0374] Below, refer to Figures 45 to 50 The manufacturing method of an electrode assembly according to an embodiment of the present invention will be described in detail.

[0375] Figure 45 and Figure 46 This is a diagram illustrating the process of manufacturing a cathode according to an embodiment of the present invention. Specifically, Figure 45 This is a top view of the cathode sheet from above. Figure 46 View from the front Figure 45 Front view of the cathode sheet.

[0376] Reference Figure 45 and Figure 46 An embodiment of the present invention describes a method for manufacturing an electrode assembly, which includes the following steps: manufacturing a cathode sheet 400S in such a manner that a cathode active material portion 420 coated with cathode active material and a cathode uncoated portion 430 without cathode active material are alternately arranged.

[0377] Specifically, a cathode active material portion 420 is formed by coating a cathode active material along a third direction d3. Furthermore, the coating area is separated along a fourth direction d4, perpendicular to the third direction d3, so that the multiple cathode active material portions 420 are arranged separately along the fourth direction d4. That is, the coating process is performed such that an uncoated cathode portion 430 is provided between the multiple cathode active material portions 420.

[0378] Here, the third direction d3 and the fourth direction d4 are directions described with reference to the cathode sheet 400S, and are directions that are independent of the first direction d1 and the second direction d2 on the gel roll structure 300S described earlier.

[0379] Next, the cathode 400 is manufactured by slitting the uncoated portion 430 and the active material portion 420 of the cathode. Figure 47 This is a perspective view of a cathode according to an embodiment of the present invention.

[0380] Reference Figures 45 to 47 , such as in Figure 45 and Figure 46 As shown by dashed lines, the uncoated portion 430 and the active material portion 420 of the cathode are cut along a direction parallel to the third direction d3. This allows for the fabrication of multiple cathode sheets 400S. Figure 47 The cathode shown is 400. That is, Figure 47 The cathode 400 is equivalent to... Figure 45 and Figure 46 A cathode is one of various cathodes manufactured by cutting open a cathode sheet 400S. In the cathode sheet 400S, the uncoated portion 430 and the active material portion 420 of the cathode are cut open respectively, thereby manufacturing a cathode 400 in which the uncoated portion 430 of the cathode extends to one side.

[0381] When forming the cathode active material portion 420, a slurry including the cathode active material can be coated onto the cathode current collector 410. During such slurry coating process, a cathode boundary portion 420B is formed at the boundary between the cathode active material portion 420 and the cathode uncoated portion 430, where the load decreases as it approaches the cathode uncoated portion 430.

[0382] Figure 48 and Figure 49 This is a diagram illustrating the process of manufacturing an anode according to an embodiment of the present invention. Specifically, Figure 48 This is a top view of the anode sheet from above. Figure 49 View from the front Figure 48 Front view of the anode sheet.

[0383] Reference Figure 48 and Figure 49An embodiment of the present invention describes a method for manufacturing an electrode assembly, comprising the following steps: manufacturing an anode sheet 500S in such a manner that an anode active material portion 520 coated with an anode active material and an anode uncoated portion 530 uncoated with an anode active material are alternately arranged.

[0384] Specifically, an anode active material portion 520 is formed by coating an anode active material along a third direction d3. Furthermore, the multiple anode active material portions 520 are arranged separately by adjusting the coating interval along a fourth direction d4 perpendicular to the third direction d3. That is, the coating process is performed such that an anode uncoated portion 530 is arranged between the multiple anode active material portions 520.

[0385] Here, the third direction d3 and the fourth direction d4 are directions used for explanation based on the anode sheet 500S, and are directions that are independent of the first direction d1 and the second direction d2 on the gel roll structure 300S described above.

[0386] Next, the anode 500 is manufactured by cutting the uncoated portion 530 and the active material portion 520 of the anode. Figure 50 This is a perspective view showing an anode 500 according to an embodiment of the present invention.

[0387] Reference Figures 48 to 50 ,like Figure 48 and Figure 49 The portion shown by the dashed line is cut along a direction parallel to the third direction d3, separating the uncoated anode portion 530 and the anode active material portion 520. This allows for the fabrication of multiple anode sheets 500S. Figure 50 The anode shown is 500. That is, Figure 50 The anode 500 is equivalent to Figure 48 and Figure 49 An anode is one of various anodes manufactured by cutting open an anode sheet 500S. In the anode sheet 500S, the uncoated portion 530 and the active material portion 520 of the anode are cut open respectively, thereby manufacturing an anode 500 in which the uncoated portion 530 extends to one side.

[0388] When forming the anode active material portion 520, a slurry including the anode active material is applied to the anode current collector 510. During this slurry application process, an anode boundary portion 520B is formed at the boundary between the anode active material portion 520 and the anode uncoated portion 530, where the load decreases as it approaches the anode uncoated portion 530.

[0389] Reference Figure 43 , Figure 47 and Figure 50The process involves winding the manufactured cathode 400 and anode 500 together with the separation membrane 600 to form a gel roll structure 300S. In this case, in the gel roll structure 300S, the uncoated portion 430 of the cathode extends further than the separation membrane 600 in the first direction d1, and the uncoated portion 530 of the anode extends further than the separation membrane 600 in the second direction d2 opposite to the first direction d1.

[0390] Re-reference Figures 48 to 50 In a method for manufacturing an electrode assembly according to an embodiment of the present invention, the anode sheet 500S includes a load-reducing region 500DA with a lower loading of the anode active material compared to adjacent regions. The method for forming the load-reducing region 500DA is not particularly limited; as an example, it can be formed by adjusting the coating degree of the slurry.

[0391] In the step of manufacturing the anode 500 described above, the load reduction region 500DA is cut open in the anode active material section 520. The cut load reduction region 500DA is... Figure 43 and Figure 44 The gel roll structure 300S shown has a load reduction section 500D formed with a smaller load of anolyte material than the adjacent region.

[0392] Specifically, a load reduction region 500DA is formed in the anolyte portion 520 of the anode sheet 500S, where the load of the anolyte is less than that in the adjacent regions. For example... Figure 49 As shown, the load reduction region 500DA is formed in the center of the anode active material portion 520. On the other hand, the load reduction region 500DA is configured such that the load of the anode active material gradually decreases as it approaches the center portion 500C of the load reduction region 500DA. In the step of manufacturing the anode 500, the load reduction portion 500D of this embodiment is provided by cutting open the center portion 500C of the load reduction region 500DA.

[0393] That is, when coating a slurry including an anolyte, a load reduction region 500DA is formed, and by cutting open the central portion 500C of the load reduction region 500DA, a plurality of anodes 500 having load reduction portions 500D are manufactured.

[0394] Reference Figure 50 The anode 500 has a load reduction portion 500D at one end and an anode uncoated portion 530 at the other end opposite to the first end.

[0395] Reference Figure 43 and Figure 44When such an anode 500 is wound up to form a gel roll structure 300S, the load reduction portion 500D is located at one end of the anode 500 in the first direction d1, and the uncoated portion 530 of the anode is located at one end of the anode 500 in the second direction d2.

[0396] Furthermore, as the central portion 500C of the load reduction region 500DA is cut open, the load of the anode active material in the load reduction portion 500D gradually decreases as it approaches the first direction d1.

[0397] Furthermore, in the gel roll structure 300S, a cathode active material portion 420 is provided in the portion corresponding to the load reduction portion 500D, with reference to a direction perpendicular to the first direction d1. More specifically, in the gel roll structure 300S, a cathode boundary portion 420B is provided in the portion corresponding to the load reduction portion 500D, with reference to a direction perpendicular to the first direction d1.

[0398] The corresponding positional relationship between the load reduction section 500D and the cathode boundary section 420B is repeated as described above, so it is omitted.

[0399] Below, refer to Figures 51 to 54 The electrode assembly of the comparative example of the present invention will be described, and the advantages of the electrode assembly of this embodiment compared with the electrode assembly of the comparative example will be explained.

[0400] Figure 51 This is a diagram illustrating an electrode assembly of a comparative example of the present invention. Figure 52 It shows along Figure 51 The cross-sectional view of the section cut by the cutting line B-B'.

[0401] Reference Figure 51 and Figure 52 The electrode assembly 600 of the comparative example of the present invention includes a cathode 700, an anode 800 and a separation membrane 900, and the cathode 700, the anode 800 and the separation membrane 900 are rolled up to form a gel roll structure 600S.

[0402] The cathode 700 includes a cathode current collector 710, a cathode active material portion 720, and a cathode uncoated portion 730. Furthermore, the cathode uncoated portion 730 extends in a first direction d1, and the cathode active material portion 720 includes a cathode boundary portion 720B that forms the boundary between the cathode active material portion 720 and the cathode uncoated portion 730 and gradually decreases in load.

[0403] Figure 53 This is a diagram illustrating the process of manufacturing a cathode 700 according to a comparative example of the present invention.

[0404] Reference Figure 53A cathode sheet 700S is manufactured by alternately arranging the cathode active material portion 720 and the cathode uncoated portion 730 along the fourth direction d4, and then the cathode uncoated portion 730 and the cathode active material portion 720 are slitting to manufacture a plurality of cathodes 700.

[0405] On the other hand, re-referencing Figure 51 and Figure 52 The anode 800 includes an anode current collector 810, an anode active material portion 820, and an anode uncoated portion 880. Furthermore, the anode uncoated portion 830 extends in a second direction d2 opposite to the first direction d1, and the anode active material portion 820 includes an anode boundary portion 820B that forms the boundary between the anode active material portion 820 and the anode uncoated portion 830 and gradually decreases in load.

[0406] Figure 54 This is a diagram illustrating the process of manufacturing an anode 800 according to a comparative example of the present invention.

[0407] Reference Figure 54 An anode sheet 800S is manufactured by alternately arranging the anode active material portion 820 and the anode uncoated portion 830 along the fourth direction d4, and then the anode uncoated portion 830 and the anode active material portion 820 are slitting to manufacture a plurality of anodes 800.

[0408] Subsequently, the manufactured cathode 700 and anode 800 are wound together with the separation membrane 900 to manufacture the electrode assembly 600 according to a comparative example of the present invention.

[0409] That is, the electrode assembly 600 of the comparative example of the present invention, except for the load reduction section (500D, see reference 500D), is different. Figure 44 In addition to having a structure similar to the electrode assembly 300 of this embodiment, it also has a similar structure.

[0410] Reference Figure 51 and Figure 52 In the case of the electrode assembly 600 of this comparative example, the anode active material portion 820 is provided at the portion corresponding to the cathode boundary portion 720B, with reference to the direction perpendicular to the first direction d1. If the anode active material portion 820 extends to the portion corresponding to the cathode boundary portion 720B, this portion has a low N / Pratio value, and the possibility of lithium metal deposition is high. Therefore, in order to prevent lithium deposition, the length of the anode active material portion 820 must be limited. That is, the anode active material portion 820 is formed only in the region B1 shown in the figure, and the anode active material portion 820 cannot be formed in the region B2. This results in a reduction in the length of the anode active material portion 820 due to the cathode boundary portion 720B.

[0411] Conversely, refer to Figure 43 and Figure 44 In the case of the electrode assembly 300 of this embodiment, with reference to the direction perpendicular to the first direction d1, the anode active material portion 520 is provided in the portion corresponding to the cathode boundary portion 420B, and a load reduction portion 500D is specifically provided. Since the load reduction portion 500D, which has a smaller load of anode active material than the adjacent region, is provided at the position corresponding to the cathode boundary portion 420B, a higher N / Pratio can be maintained in this portion, and lithium deposition can be prevented. As a result, the anode active material portion 520 can be formed to the extent of region A1, and the region A2, where the anode active material portion 520 cannot be formed, is reduced. As an example, the width in the height direction of the anode 500 can be increased to more than 98% relative to the width in the height direction of the cathode 400.

[0412] right Figure 43 and Figure 44 The A1 area and Figure 51 and Figure 52 By comparing the regions of B1, it can be seen that the electrode assembly 300 of this embodiment can increase the length of the anode active material portion to the extent corresponding to the load reduction portion 500D. Therefore, compared with the electrode assembly 600 of the comparative example, it can have a higher energy density in a further defined space.

[0413] Another aspect of the present invention relates to a cylindrical battery comprising: a gel roll type electrode assembly having a structure in which an anode, a cathode, and a separation membrane sandwiched between the anode and cathode are wound in one direction; a cylindrical battery casing housing the electrode assembly; and a battery case being a sealing body disposed on the upper part of the battery casing and sealing the battery casing. Here, the anode is the anode of the present invention, and the anode active material includes an average particle size D. 50 These are single-particle-based active material particles smaller than 5 μm. The aforementioned cylindrical battery also includes an electrolyte; for details regarding the electrolyte, please refer to the above information.

[0414] The electrode assembly described above has a structure of the stacked type, stacked / folded type, or gel roll type as described above. In a specific embodiment of the present invention, as described above, the anode of the electrode assembly has a load reduction portion.

[0415] In the case of conventional cylindrical batteries, there is a problem that the current is concentrated at the strip-shaped electrode tabs, which leads to increased resistance, more heat generation, and poor current collection efficiency.

[0416] In recent years, with the development of electric vehicle technology, the demand for high-capacity batteries has increased, necessitating the development of large cylindrical batteries. Previously, small cylindrical batteries with form factors of 1865 or 2170, used in general, did not significantly impact battery performance due to their small capacity, thus resistance or heat generation did not have a serious impact. However, directly applying the design structure of previous small cylindrical batteries to large cylindrical batteries would pose serious safety risks.

[0417] It is believed that as the size of a battery increases, the amount of heat and gas generated inside the battery also increases. This heat and gas cause the internal temperature and pressure of the battery to rise, potentially leading to battery fire or explosion. To prevent this, it is necessary to properly expel the heat and gas from the battery to the outside. This requires increasing the cross-sectional area of ​​the battery, which serves as a channel for expelling heat to the outside, in line with the increase in volume. However, the increase in cross-sectional area usually does not match the increase in volume. The larger the battery, the greater the heat generation inside, thus increasing the risk of explosion and causing problems such as reduced power. In addition, during rapid charging at high voltage, a large amount of heat is generated around the electrode tabs in a short period of time, causing the battery to catch fire. To address this, the present invention provides a cylindrical battery that achieves high capacity while maintaining high safety in a large volume.

[0418] Furthermore, the high-load electrode, which is suitable for the above-mentioned single-particle or similar single-particle morphology, can be applied to cylindrical batteries, thereby improving the initial resistance characteristics and charge / discharge efficiency of cylindrical batteries.

[0419] The cylindrical battery of the present invention uses a single-particle or similar single-particle morphology anode active material, which significantly reduces the amount of gas generated compared with the past, thereby demonstrating excellent safety even in large cylindrical batteries with a shape factor ratio of 0.4 or more.

[0420] The cylindrical battery of the present invention is preferably a battery without electrode tabs and thus without a tab-less structure, but is not limited thereto.

[0421] The battery with the aforementioned tabless structure has the following structure: for example, the anode and cathode each include an uncoated portion without an active material layer, and the anode uncoated portion and cathode uncoated portion are respectively provided at the upper and lower ends of the electrode assembly. The anode uncoated portion and cathode uncoated portion are combined with a current collector, and the current collector is connected to the electrode terminals.

[0422] As mentioned above, when a cylindrical battery is formed with a tabless structure, the degree of current concentration is reduced compared to conventional batteries with electrode tabs. Therefore, the heat generated inside the battery can be effectively reduced, thereby improving the thermal safety of the battery.

[0423] The present invention will now be described in detail through specific embodiments.

[0424] Example 1

[0425] Will have an average particle size D 50 Li[Ni], an anolyte with a single-peak particle size distribution of 3 μm and a single-particle morphology. 0.9 Co 0.06 Mn 0.03 Al 0.01 An anode solder was prepared by mixing O2, carbon nanotubes, and PVDF binder in N-methylpyrrolidone at a weight ratio of 97.8:0.6:1.6. The anode solder was then coated onto one side of an aluminum current collector, dried at 120°C, and subsequently rolled to produce the anode.

[0426] A cathode paste was prepared by mixing cathode active material (graphite:SiO = 95:5 by weight), conductive material (super C), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) in water at a weight ratio of 96:2:1.5:0.5. The cathode paste was then coated onto one side of a copper current collector, dried at 150°C, and subsequently calendered to produce the cathode.

[0427] A gel roll type electrode assembly was manufactured by sandwiching a separator membrane between the anode and cathode as described above, and then sequentially stacking the separator membrane / anode / separation membrane / cathode and winding them up. The electrode assembly manufactured as described above was then inserted into a cylindrical battery casing and electrolyte was injected to manufacture a 4680 battery.

[0428] Comparative Example 1

[0429] In addition to being used as an anode active material, it also utilizes a large average particle size D. 50 The average particle size is 9 μm, and the smallest particle size is D. 50 Li[Ni] with a bimodal particle size distribution and secondary particle morphology of 4 μm 0.9 Co 0.05 Mn 0.04 Al 0.01 Apart from the O2 point, the 4680 battery was manufactured using the same method as in Example 1.

[0430] Experimental Example 1

[0431] A hot box test was performed on the 4680 batteries manufactured according to Example 1 and Comparative Example 1.

[0432] Specifically, the 4680 batteries manufactured according to Example 1 and Comparative Example 1 were placed in a hot box chamber at room temperature and heated to 130°C at a heating rate of 5°C / min, then held for 30 minutes for hot box evaluation. The temperature change of the battery over time was measured. To ensure accurate evaluation, the battery of Example 1 underwent two hot box evaluations. The test results are illustrated in [figure not provided]. Figure 40a and Figure 40b .

[0433] Figure 40a This is a graph showing the hot box test results of the 4680 battery manufactured according to Example 1. Figure 40b This is a graph showing the results of the hot box test of the 4680 battery manufactured by Comparative Example 1.

[0434] pass Figure 40a and Figure 40b It can be seen that in the case of the lithium secondary battery of Example 1 using single-particle anode active material, the battery voltage and temperature remained stable until 65 minutes, while the lithium secondary battery of Comparative Example 1 showed a sharp rise in battery temperature after 35 minutes.

[0435] Example 2-1

[0436] Prepared with a unimodal particle size distribution, D min =1.78μm, D 50 =4.23μm, D max =13.1μm, mixed with single-particle and similar single-particle anolyte active materials (composition: Li[Ni 0.9 Co 0.06 Mn 0.03 Al 0.01 O2). Figure 39a SEM images of the anolyte used in Example 2-1 are shown.

[0437] An anode solder was prepared by mixing anolyte, carbon nanotubes, and PVDF binder in N-methylpyrrolidone at a weight ratio of 97.8:0.6:1.6. The anode solder was then coated onto one side of an aluminum current collector, dried at 120°C, and subsequently rolled to produce the anode.

[0438] A cathode paste was prepared by mixing cathode active material (graphite:SiO = 95:5 by weight), conductive material (Super C), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) in water at a weight ratio of 96:2:1.5:0.5. The cathode was then manufactured by coating the cathode paste onto one side of a copper current collector and drying it at 150°C followed by calendering.

[0439] A gel roll type electrode assembly was manufactured by sandwiching a separator membrane between the anode and cathode as described above, and then stacking them in the order of separator membrane / anode / separator membrane / cathode, and then winding them up. The electrode assembly manufactured as described above was then inserted into a battery case and electrolyte was injected to manufacture a 4680 battery.

[0440] Example 2-2

[0441] In addition to being used as an anode active material, D has a unimodal particle size distribution. min =1.38μm, D 50 =4.69μm, D max =18.5μm, mixed with single-particle and similar single-particle anolyte active materials (composition: Li[Ni 0.9 Co 0.06 Mn 0.03 Al 0.01 Apart from the point of O2), the 4680 battery was manufactured by the same method as in Example 2-1. Figure 39b SEM images of the anodic active material used in Examples 2-2 are shown.

[0442] Comparative Example 2-1

[0443] In addition to being used as an anode active material, it also utilizes a large average particle size D. 50 The average particle size is 9 μm, and the smallest particle size is D. 50 An anolyte with a bimodal particle size distribution and secondary particle morphology, measuring 4 μm (composition: Li[Ni 0.9 Co 0.05 Mn 0.04 Al 0.01 Apart from the point of O2), the 4680 battery was manufactured by the same method as in Example 2-1.

[0444] Comparative Example 2-2

[0445] In addition to being used as an anode active material, D has a unimodal particle size distribution. min =0.892μm, D 50 =3.02μm, D max =11μm, a mixture of single-particle and similar single-particle anolyte active materials (composition: Li[Ni 0.9 Co 0.06 Mn 0.03 Al 0.01 Apart from the point of O2), the 4680 battery was manufactured by the same method as in Example 2-1.

[0446] Figure 39c SEM images of the anolyte used in Comparative Examples 2-2 are shown.

[0447] Experimental Example 2-1

[0448] Hot box tests were performed on the 4680 batteries manufactured using Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-2.

[0449] Specifically, the 4680 batteries manufactured according to Example 2-1 and Comparative Example 2-1 were placed in a hot box chamber at room temperature and heated to 130°C at a heating rate of 5°C / min, then held for 30 minutes. The temperature change of the batteries was then measured. A test was considered passable if no thermal runaway or fire occurred, and failable if thermal runaway and / or fire occurred. Furthermore, to ensure the accuracy of the test, the batteries from Examples 2-1 to 2-2 were tested at least twice.

[0450] The test results are illustrated in Table 1 below. Figure 40c , Figure 40d . Figure 40c This is a graph showing the hot box test results of the 4680 batteries manufactured using Sample 1 of Example 2-1 and Comparative Example 2-1. Figure 40d This is a graph showing the hot box test results of 4680 batteries manufactured using samples 2 and 3 of Example 2-1, samples 1 and 2 of Example 2-2, and Comparative Example 2-2.

[0451] Table 1

[0452]

[0453]

[0454] Refer to Table 1 above. Figure 40c and Figure 40d It can be seen that when applying D min In the case of the 4680 battery of Example 2-1, which uses a single-particle / similar single-particle morphology of 1.0 μm or larger as the anode active material, the battery voltage and temperature remained stable after 65 minutes. Comparative Example 2-1, which uses secondary particles as the anode active material, and D... min In the case of the 4680 battery of Comparative Example 2-2, which uses anode active material with a single particle / similar single particle morphology of less than 1.0 μm, the battery temperature rises sharply.

[0455] Experimental Example 2-2

[0456] To confirm the degree of particle breakage of the anodic active material after calendering the anodes manufactured in Example 2-1 and Comparative Example 2-1, the cross-sections were photographed using SEM after the anodes were cut by an ion milling apparatus. Figure 41a The image shown is a cross-sectional SEM photograph of the anode manufactured in Example 2-1. Figure 41b A cross-sectional SEM image of the anode manufactured in Comparative Example 2-1 is shown.

[0457] pass Figure 41a and Figure 41b It was observed that the anode of Example 2-1 showed almost no particle breakage of the anode active material after calendering, while the anode of Comparative Example 2-2, which used secondary particles, showed multiple particle breakages of the anode active material after calendering.

[0458] Example 3-1

[0459] It will have a unimodal particle size distribution, D min =1.78μm, D 50 =4.23μm, D max =13.1μm, and mixed with single-particle and similar single-particle anolyte powders (composition: Li[Ni 0.9 Co 0.06 Mn 0.03 Al 0.01 An anode solder was prepared by mixing O2, flake graphite (SFG6L), conductive material (multi-walled carbon nanotubes), and PVDF binder in N-methylpyrrolidone at a weight ratio of 96.3:1.5:0.4:1.8. The anode solder was coated onto one side of an aluminum current collector, dried, and then rolled at a wire pressure of 3.0 ton / cm to produce the anode. The porosity of the anolyte layer of the anode manufactured as described above was tested, and the porosity was found to be 17.5%.

[0460] Example 3-2

[0461] Except for the point where the anolyte, flake graphite, conductive material, and binder are mixed in a weight ratio of 97.2:0.6:0.4:1.8, the anode was manufactured in the same manner as in Example 3-1, and the porosity of the anolyte layer was measured. The measured porosity of the anolyte layer was 19%.

[0462] Example 3-3

[0463] Except for the point where the anolyte, flake graphite, conductive material, and binder are mixed in a weight ratio of 97.4:0.4:0.4:1.8, the anode was manufactured in the same manner as in Example 3-1, and the porosity of the anolyte layer was measured. The measured porosity of the anolyte layer was 20%.

[0464] Examples 3-4

[0465] Except for the point where the anolyte, flake graphite, conductive material, and binder are mixed in a weight ratio of 97.6:0.2:0.4:1.8, the anode was manufactured in the same manner as in Example 3-1, and the porosity of the anolyte layer was measured. The measured porosity of the anolyte layer was 21%.

[0466] Comparative Example 3-1

[0467] Except for the point where the anode solder is manufactured by mixing the anolyte, conductive material, and binder in N-methylpyrrolidone at a weight ratio of 97.8:0.4:1.8 without adding flake graphite, the anode was manufactured in the same manner as in Example 3-1, and the porosity of the anolyte layer was measured. The measured porosity of the anolyte layer was 24%.

[0468] Comparative Example 3-2

[0469] Except for the absence of flake graphite, the anode was manufactured by mixing the anolyte, conductive material, and binder in N-methylpyrrolidone at a weight ratio of 97.8:0.4:1.8 to produce the anolyte solder, and then rolling it at a line pressure of 2.0 ton / cm. The anode was manufactured in the same manner as in Example 3-1, and the porosity of the anolyte layer was measured. The measured porosity of the anolyte layer was 30%.

[0470] Experimental Example 3-1 - Detection of Charge / Discharge Capacity and Charge / Discharge Efficiency

[0471] Coin cells comprising the anodes of Examples 3-1 to 3-4 and Comparative Examples 3-1 and 3-2 were manufactured, charged to 4.25V at a current of 0.2C, and then discharged to 2.5V at a current of 0.2C. The charge capacity (mAh / g) and discharge capacity (mAh / g) of each coin cell were measured. The test results are shown in Table 2 below.

[0472] Table 2

[0473]

[0474]

[0475] As shown in Table 2, Examples 3-1 to 3-4, which use anodes with added flake graphite, exhibited lower porosity and superior capacity characteristics compared to Comparative Examples 3-1 to 3-2.

[0476] Experiment Example 3-2 - Confirmation of Resistance Characteristics

[0477] The resistance characteristics generated by SOC were measured by charging a coin cell containing the anodes of Examples 3-3, 3-1, and 3-2 to 4.2V. The experimental results are as follows: Figure 42a As shown.

[0478] Reference Figure 42a It can be seen that, based on a SOC of 10%, the resistivity of Example 3-3, which has flake graphite added to the anolyte layer, is lower than that of Comparative Examples 3-1 and 3-2, which do not contain flake graphite. This indicates that adding flake graphite to the anolyte layer has the effect of improving the resistivity characteristics at a lower SOC.

[0479] Experimental Example 3-3 - Detection of High-Temperature Lifetime Characteristics and Resistance Increase Rate

[0480] A gel roll type electrode assembly was manufactured by sandwiching a separation membrane between the anode and cathode in Examples 3-1, 3-3, and Comparative Example 3-1, and then rolling them up in the order of separation membrane / anode / separation membrane / cathode. The electrode assembly manufactured as described above was inserted into a cylindrical battery case and then an electrolyte was injected to manufacture a 4680 battery.

[0481] At this time, the cathode is prepared by the following method: the cathode active material (graphite:SiO = 95:5 weight ratio mixture), conductive material (super C), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are mixed in water at a weight ratio of 96:2:1.5:0.5 to prepare a cathode slurry. The cathode slurry is then coated onto one side of a copper current collector, dried at 150°C, and then calendered.

[0482] The 4680 batteries manufactured as described above were charged at 40°C to 4.2V at 0.5C and then discharged at 0.5C to 2.5V, with one cycle constituting 50 charge-discharge cycles. After this process, the capacity retention and DCIR increase were measured. The test results are as follows: Figure 42b As shown.

[0483] Reference Figure 42bIn the case of the secondary batteries of Examples 3-1 and 3-3, compared with the secondary battery of Comparative Example 3-1, the change in capacity retention rate based on the number of cycles is small, and the change in resistance increase rate based on the number of cycles is also small.

[0484] The present invention has been described above with reference to specific embodiments and accompanying drawings. However, the present invention is not limited thereto. Those skilled in the art can make various modifications and variations within the equivalent scope of the technical concept of the present invention and the claims described below.

Claims

1. A cylindrical battery characterized by comprising: Comprising: an electrode assembly having a first electrode tab and a second electrode tab; a battery case receiving the electrode assembly through an open portion formed at one side and electrically connected to the first electrode tab; a first current collector plate located inside the battery case and including a support portion disposed at one side of the electrode assembly, at least one first tab coupling portion extending from the support portion to be coupled to the first electrode tab, and at least one first case coupling portion extending from the support portion to be coupled to an inner side surface of the battery case; a second current collector plate having a rim portion disposed at the other side of the electrode assembly, a second tab coupling portion extending from the rim portion to be coupled to the second electrode tab, and a terminal coupling portion disposed separately from the second tab coupling portion; a cover sealing the open portion of the battery case; and a battery terminal electrically connected to the second electrode tab by being coupled to the terminal coupling portion.

2. The cylindrical battery according to claim 1, wherein: the battery case includes a crimped portion formed at an end portion adjacent to the open portion and pressed inwardly, the first case coupling portion is coupled to the crimped portion.

3. The cylindrical battery according to claim 1, wherein: the first case coupling portion includes: a first contact portion coupled to the inner side surface of the battery case, and a first connecting portion connecting between the support portion and the first contact portion.

4. The cylindrical battery according to claim 3, wherein: at least a portion of the first contact portion extends along an inner peripheral surface of the battery case.

5. The cylindrical battery according to claim 3, wherein: the first connecting portion includes at least one first curved portion changing an extension direction.

6. The cylindrical battery according to claim 1, wherein: the first current collector plate further includes a second case coupling portion extending from an end portion of the first tab coupling portion to be coupled to the inner side surface of the battery case.

7. The cylindrical battery according to claim 6, wherein: the second case coupling portion includes: a second contact portion coupled to the inner side surface of the battery case, and a second connecting portion connecting between the first tab coupling portion and the second contact portion.

8. The cylindrical battery according to claim 7, wherein: at least a portion of the second contact portion extends along the inner peripheral surface of the battery case.

9. The cylindrical battery according to claim 7, wherein: the second connecting portion includes at least one second curved portion changing an extension direction.

10. The cylindrical battery according to claim 1, wherein: the rim portion is a wheel rim shape having a center portion thereof empty.

11. The cylindrical battery according to claim 1, wherein: the second tab coupling portion and the terminal coupling portion are electrically connected through the rim portion.

12. The cylindrical battery according to claim 1, wherein: The terminal joining portion is located at a center portion of an inner side space of the edge portion.

13. The cylindrical battery according to claim 1, wherein The second current collecting plate further includes a tab extending inward from the edge portion to connect with the terminal joining portion.

14. The cylindrical battery according to claim 13, wherein At least a portion of the tab is narrower in width than the second tab joining portion.

15. The cylindrical battery according to claim 14, wherein The tab has a tapered portion that gradually narrows in width from an inner side surface of the edge portion in a direction toward the terminal joining portion.

16. The cylindrical battery according to claim 13, wherein The second tab joining portion is formed in a plurality.

17. The cylindrical battery according to claim 16, wherein The plurality of second tab joining portions are arranged at the same intervals from each other in the extending direction of the edge portion.

18. The cylindrical battery according to claim 16, wherein The extending lengths of the plurality of second tab joining portions are the same as each other.

19. The cylindrical battery according to claim 16, wherein The terminal joining portion is arranged surrounded by the plurality of second tab joining portions.

20. The cylindrical battery according to claim 16, wherein The tab is located between a pair of second tab joining portions adjacent to each other, The distance from the tab to either of the pair of second tab joining portions in the extending direction of the edge portion is the same as the distance from the tab to the other of the pair of second tab joining portions in the extending direction of the edge portion.

21. The cylindrical battery according to claim 16, wherein The tab is formed in a plurality.

22. The cylindrical battery according to claim 21, wherein The plurality of tabs are arranged between a pair of second tab joining portions adjacent to each other, respectively.

23. The cylindrical battery according to claim 21, wherein The plurality of tabs are arranged at the same intervals from each other in the extending direction of the edge portion.

24. The cylindrical battery according to claim 13, wherein The tab has a slotted portion formed in a manner to reduce the width of the tab.

25. The cylindrical battery according to claim 15, wherein The tab has a slotted portion formed in a manner to reduce the width of the tab, The slotted portion is arranged closer to the tapered portion than the terminal joining portion.

26. The cylindrical battery according to claim 1, wherein The terminal joining portion is arranged at a position corresponding to a hole formed at a winding center portion of the electrode assembly.

27. The cylindrical battery according to claim 1, wherein The second electrode tab extends toward a closed portion opposite to the open portion of the battery case.

28. The cylindrical battery according to claim 27, wherein The second tab-joining portion is joined to an end of the second electrode tab bent in a direction parallel to the second current collector plate.

29. The cylindrical battery according to claim 1, wherein The cover plate is not connected to the electrode assembly and does not have polarity.

30. The cylindrical battery according to claim 1, wherein The battery terminal penetrates the closed portion opposite the open portion of the battery case.

31. The cylindrical battery according to claim 30, wherein The cylindrical battery further includes an insulator interposed between the closed portion and the second current collector plate.

32. The cylindrical battery according to claim 31, wherein The battery terminal is joined to the terminal-joining portion of the second current collector plate via the insulator.

33. The cylindrical battery according to claim 1, wherein The active material layer of the second electrode includes an anode active material having single particles, quasi-single particles, or a combination thereof, the quasi-single particles being aggregates of one or less primary particles, The minimum particle size D shown in the volume cumulative distribution of the anode active material min is 1.0 μm or more, The particle size D at which the volume cumulative amount is 50% in the volume cumulative distribution of the above anode active material 50 is 5.0 μm or less, The maximum particle size D shown in the volume cumulative distribution of the anode active material described above is max is 12 μm to 17 μm.

34. The cylindrical battery according to claim 33, wherein The anode active material has a unimodal particle size distribution (PSD) shown by a single peak in a volume cumulative particle size distribution graph, the PSD being 3 or less as shown by the following equation: Particle size distribution (PSD) = (D max - D min ) / D 50 .

35. The cylindrical battery according to claim 33, wherein The single particles, quasi-single particles, or combination thereof are included in an amount of 95 to 100 wt% based on the total weight of the anode active material included in the active material layer of the second electrode.

36. The cylindrical battery according to claim 33, wherein The anode active material includes a lithium-nickel-based oxide including 80 mol% or more of Ni based on the total number of moles of transition metals.

37. The cylindrical battery according to claim 33, wherein The active material layer of the second electrode has a porosity of 15 to 23%, The active material layer of the second electrode includes flaky graphite in a weight ratio of 0.05 to 5 wt%.

38. The cylindrical battery according to claim 33, wherein The active material layer of the second electrode further includes carbon nanotubes.

39. The cylindrical battery according to claim 33, wherein The active material layer of the first electrode includes a silicon-based cathode active material and a carbon-based cathode active material, and the silicon-based cathode active material and carbon-based cathode active material are included in a weight ratio of 1:99 to 20:

80.

40. A battery pack, comprising: The battery pack includes the cylindrical battery according to any one of claims 1 to 39.

41. An automobile characterized by comprising: It includes the battery pack according to claim 40.

Images