Cylindrical battery cell, battery pack including same, and automobile

Abstract

A cylindrical battery cell according to one embodiment of the present invention includes a jelly roll having a first electrode tab protruding upward and a second electrode tab protruding downward; a battery can that accommodates the jelly roll through an opening at the top end and is electrically connected to the second electrode tab; a first current collecting plate that is coupled to the first electrode tab at the top of the jelly roll; an insulating shrink tube that includes a first cover portion that covers at least a portion of the first current collecting plate and a second cover portion that covers the top end of the outer circumferential surface of the jelly roll; and an upper cap that is electrically connected to the first current collecting plate and covers the opening.

Description

[Technical field]

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

[0002] This application claims priority to Korean Patent Application No. 10-2021-0115064, filed on August 30, 2021, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings. [Background technology]

[0003] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electrical sources. These secondary batteries are attracting attention as a new energy source because they not only have the primary advantage of dramatically reducing the use of fossil fuels, but also are environmentally friendly as they do not produce any by-products associated with energy use and can improve energy efficiency.

[0004] Currently, types of secondary batteries that are widely used include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack is constructed by connecting a plurality of battery cells in series. Also, a battery pack may be constructed by connecting a plurality of battery cells in parallel according to a charge / discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack can be variously set according to a required output voltage or charge / discharge capacity.

[0005] Meanwhile, cylindrical, prismatic and pouch-type battery cells are known as types of unit secondary battery cells. In the case of a cylindrical battery cell, a separator, which is an insulator, is interposed between a positive electrode and a negative electrode, and the electrode assembly is wound up in a jelly roll shape, which is then inserted into a battery can to form a battery. Lead tabs are connected to the uncoated portions of each of the positive electrode and negative electrode, and the lead tabs are connected to components that function as electrode terminals to electrically connect the electrode assembly to the electrode terminals. However, in a conventional cylindrical battery cell having such a structure, current is concentrated in the narrow lead tabs that are connected to the uncoated positive electrode portion and / or the uncoated negative electrode portion, resulting in high resistance, large heat generation and poor current collection efficiency.

[0006] To solve these problems, a cylindrical battery cell has been proposed that has a structure in which a positive electrode uncoated portion and a negative electrode uncoated portion are located at the upper and lower ends of a jelly roll-type electrode assembly, respectively, and current collecting plates are bonded to these uncoated portions, thereby improving current collection efficiency.

[0007] However, according to such a cylindrical battery cell structure, since the positive electrode uncoated portion and the negative electrode uncoated portion protrude outward from the jelly roll, the positive electrode uncoated portion and the battery can may come into contact with each other. When the positive electrode uncoated portion and the battery can come into electrical contact with each other, a short circuit may occur. When a short circuit occurs inside the battery, the battery may heat up or explode. For this reason, there is a need to provide an insulating member for preventing electrical contact between the positive electrode uncoated portion protruding upward and the battery can.

[0008] Therefore, there is a need for a method for providing a cylindrical battery cell having a low internal resistance and a low risk of short circuiting, as well as a battery pack and an automobile including the same. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above problems, and has an object to reduce the internal resistance of a cylindrical battery cell and prevent an internal short circuit in the battery cell.

[0010] Another object of the present invention is to improve the energy density of a battery cell by minimizing the space occupied by parts applied to prevent contact between an electrode tab of a jelly roll and a battery can, and to facilitate the process of inserting a jelly roll into a battery can.

[0011] It is still another object of the present invention to improve the energy density of a cylindrical battery cell by increasing the ratio of the total height of the jelly roll to the total height of the battery can.

[0012] However, the technical problems that the present invention aims to solve are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0013] To achieve the above object, according to one aspect of the present invention, a cylindrical battery cell includes a jelly roll having a first electrode tab protruding upward and a second electrode tab protruding downward, a battery can that accommodates the jelly roll from an opening at an upper end and is electrically connected to the second electrode tab, a first current collecting plate that is coupled to the first electrode tab at an upper end of the jelly roll, an insulating shrink tube that includes a first cover portion that covers at least a portion of the first current collecting plate and a second cover portion that covers an upper end of an outer circumferential surface of the jelly roll, and an upper cap that is electrically connected to the first current collecting plate and covers the opening.

[0014] Here, the diameter of the first current collecting plate may correspond to the diameter of the jelly roll.

[0015] Alternatively, the diameter of the first current collecting plate may be smaller than the diameter of the jelly roll, and the first cover portion may cover both the first electrode tab and the first current collecting plate.

[0016] Meanwhile, the jelly roll may include a first region in which the first electrode tabs have a first length, and a second region located on an outer periphery of the first region in which the first electrode tabs have a second length.

[0017] The first length may be longer than the second length.

[0018] A distance from an outer peripheral surface of the battery can to a boundary point between the first region and the second region may be greater than or equal to a pressing depth of a beading portion formed by pressing the outer peripheral surface of the battery can.

[0019] The beading portion may be located below a bottom end of the first current collecting plate.

[0020] Here, the first current collecting plate may cover the first region of the jelly roll.

[0021] In this case, the first cover portion may cover the second region of the jelly roll and the first current collecting plate.

[0022] In addition, the first cover part may be connected to the second cover part, and a radial extension length of the first cover part may be greater than or equal to a press-in depth of a beading part formed by press-in around an outer circumferential surface of the battery can.

[0023] Meanwhile, the insulating shrink tube may include a heat shrinkable material that shrinks when heat is applied.

[0024] Meanwhile, the cylindrical battery cell may further include an electrolyte solution contained inside the battery can, and the insulating shrink tube may be made of a material that does not chemically react with the electrolyte solution.

[0025] Meanwhile, the extension length of the second cover portion may be greater than or equal to the extension length of the first electrode tab.

[0026] The present invention also provides a battery pack, the battery pack including at least one battery cell according to the above-described embodiments.

[0027] The present invention also provides a motor vehicle, the motor vehicle including at least one battery pack according to any of the above-described embodiments. Effect of the Invention

[0028] According to the present invention, the internal resistance of the battery cell can be reduced and an internal short circuit of the battery cell can be prevented.

[0029] In particular, according to the present invention, electrode tabs are formed on the upper and lower parts of the electrode assembly, and the area of ​​the electrode tabs is increased, thereby reducing the internal resistance of the battery cell.

[0030] In addition, according to the present invention, an internal short circuit of a cylindrical battery cell can be prevented by preventing electrical contact between the electrode tab and the battery can with a relatively simple structure.

[0031] In addition, the present invention can minimize the space occupied by parts applied to prevent contact between the electrode tabs of the jelly roll and the battery can, thereby improving the energy density of the battery cell and facilitating the process of inserting the jelly roll into the battery can.

[0032] Additionally, the present invention allows the ratio of the total height of the jelly roll to the total height of the battery can to be increased, thereby increasing the energy density of the cylindrical battery cell.

[0033] Therefore, according to the present invention, it is possible to provide a cylindrical battery cell having a structure in which internal resistance is reduced, internal short circuit is prevented, processability is improved, and energy density is improved, and a battery pack and an automobile including the same can be provided.

[0034] In addition, the present invention provides various other effects, which will be described in each embodiment, and descriptions of effects that can be easily inferred by those skilled in the art will be omitted.

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 illustrates a cylindrical battery cell according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a longitudinal section of the cylindrical battery cell of FIG. 1. [Diagram 3] FIG. 2 is a longitudinal cross-sectional view of the cylindrical battery cell of FIG. 1. [Figure 4] FIG. 2 is a perspective view showing the inside of the cylindrical battery cell of FIG. 1. [Diagram 5] 11A and 11B are diagrams illustrating a current collecting plate according to another embodiment of the present invention. [Figure 6] FIG. 13 shows a cylindrical battery cell according to another embodiment of the present invention. [Figure 7] FIG. 13 is a diagram showing a cylindrical battery cell according to yet another embodiment of the present invention. [Figure 8] FIG. 13 is a diagram showing a cylindrical battery cell according to yet another embodiment of the present invention. [Figure 9] FIG. 13 is a diagram showing a cylindrical battery cell according to yet another embodiment of the present invention. [Figure 10] FIG. 1 illustrates a battery pack according to an embodiment of the present invention. [Figure 11]FIG. 1 shows a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts according to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention.

[0038] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0039] It should be noted that in order to facilitate understanding of the invention, the accompanying drawings may be drawn not to scale but with some components exaggerated.

[0040] Fig. 1 is a diagram showing a cylindrical battery cell according to an embodiment of the present invention, Fig. 2 is a perspective view of a vertical section of the cylindrical battery cell of Fig. 1. Fig. 3 is a vertical section of the cylindrical battery cell of Fig. 1, and Fig. 4 is a perspective view showing the inside of the cylindrical battery cell of Fig. 1.

[0041] 1 to 4, a cylindrical battery cell 1 according to an embodiment of the present invention includes a jelly roll 10, a battery can 20, a first current collecting plate 30, an insulating shrink tube 50, and an upper cap 60. In addition to the above-mentioned components, the cylindrical battery cell 1 according to an embodiment of the present invention may further include a second current collecting plate 40 and / or an airtight gasket 70 and / or a connecting plate 80.

[0042] The jelly roll 10 is obtained by winding up an electrode assembly of a secondary battery. The jelly roll 10 includes a first electrode having a first polarity, a second electrode having a second polarity, and a separator interposed between the first and second electrodes. That is, the jelly roll 10 may be manufactured by winding up a laminate formed by sequentially stacking the first electrode, the separator, and the second electrode at least once, based on a winding center C. In this case, a separator may be further provided on the outer periphery of the jelly roll 10 for insulation from the battery can 20. The first electrode is a positive electrode or a negative electrode, and the second electrode is an electrode having a polarity opposite to that of the first electrode.

[0043] 2 and 3, the jelly roll 10 includes a first electrode tab 11 protruding from an upper portion and a second electrode tab 12 protruding from a lower portion.

[0044] The first electrode includes a first electrode collector and a first electrode active material applied to one or both sides of the first electrode collector. An uncoated portion where the first electrode active material is not applied exists at one end of the first electrode collector in the width direction (direction parallel to the Z axis). The uncoated portion functions as a first electrode tab 11. The first electrode tab 11 is provided at the upper portion of the jelly roll 10 in the vertical direction (direction parallel to the Z axis) contained in the battery can 20.

[0045] The second electrode includes a second electrode collector and a second electrode active material applied to one or both sides of the second electrode collector. An uncoated portion where the second electrode active material is not applied exists at the other end of the second electrode collector in the width direction (direction parallel to the Z axis). The uncoated portion functions as a second electrode tab 12. The second electrode tab 12 is provided at the lower part of the jelly roll 10 in the vertical direction (direction parallel to the Z axis) contained in the battery can 20.

[0046] 1 to 4, the battery can 20 is a cylindrical container having an opening at the top and made of a conductive metal material. The battery can 20 accommodates the jelly roll 10 through the opening at the top, and also accommodates an electrolyte.

[0047] The battery can 20 is electrically connected to the second electrode tab 12 of the jelly roll 10. Thus, the battery can 20 has the same polarity as the second electrode tab 12.

[0048] The battery can 20 may include a beading portion 21 formed at an upper end thereof. The battery can 20 may also include a crimping portion 22. The beading portion 21 is formed by pressing around the outer circumferential surface of the battery can 20. The beading portion 21 prevents the jelly roll 10, which has a size corresponding to the width of the battery can 20, from slipping out of the opening at the upper end of the battery can 20, and may function as a support portion on which the upper cap 60 is provided.

[0049] The crimping portion 22 is formed on the upper portion of the beading portion 21. The crimping portion 22 has a curved shape extending to surround the outer circumferential surface of the upper cap 60 disposed on the beading portion 21 and a part of the upper surface of the upper cap 60.

[0050] However, the battery can 20 of the present invention may not have such a beading portion 21 and / or a crimping portion 22. In this case, the fixing of the jelly roll 10 and / or the fixing of the top cap 60 and / or the sealing of the battery can 20 may be achieved, for example, by adding a part that functions as a stopper for the jelly roll 10 and / or adding a structure to which the top cap 60 is attached and / or welding the battery can 20 and the top cap 60 together.

[0051] 3 and 4, a cylindrical battery cell 1 according to an embodiment of the present invention includes a first current collecting plate 30. The cylindrical battery cell 1 may further include a second current collecting plate 40. The first current collecting plate 30 and the second current collecting plate 40 are made of a conductive metal material.

[0052] The first current collecting plate 30 is coupled to the first electrode tab 11 at the top of the jelly roll 10. A lead L made of a conductive metal material may be connected to the first current collecting plate 30. The lead L may extend upward from the jelly roll 10 and be directly coupled to the top cap 60, or may be coupled to a connection plate 80 coupled to the bottom surface of the top cap 60.

[0053] Referring to FIG. 4, the first current collecting plate 30 may have, for example, a substantially circular disk shape. Since the first current collecting plate 30 has a circular disk shape, the first current collecting plate 30 may have a shape corresponding to the upper surface of the first electrode tab 11 coupled to the lower portion. Referring to FIG. 3, the diameter of the first current collecting plate 30 may correspond to the diameter of the jelly roll 10. That is, the first current collecting plate 30 may have a shape corresponding to the entire area of ​​the upper surface (a surface parallel to the XY plane) of the jelly roll 10 coupled to the lower portion. With this structure, the contact area between the first electrode tab 11 and the first current collecting plate 30 is maximized, so that the internal resistance of the battery may be reduced.

[0054] 5, the first current collecting plate 30 may be substantially disk-shaped with at least one opening H formed penetrating in the vertical direction (parallel to the Z-axis). In this case, the shape of the opening H is not limited. The at least one opening H may facilitate injection of the electrolyte into the jelly roll 10.

[0055] Alternatively, although not shown, the first current collecting plate 30 may include a plurality of sub-plates extending radially from a center portion, which may facilitate injection of electrolyte between the plurality of sub-plates.

[0056] Referring to FIG. 3, the first current collecting plate 30 may be coupled to an end of the first electrode tab 11. Alternatively, unlike the drawing, the end of the first electrode tab 11 may be bent in a direction parallel to the first current collecting plate 30 (parallel to the XY plane). In this case, the first current collecting plate 30 may be coupled to the facing first electrode tab 11 by bending. In this case, the length of the electrode tab 11 in the height direction (parallel to the Z axis) in the battery can 20 is minimized, thereby increasing the energy density. In addition, the bonding area between the first current collecting plate 30 and the first electrode tab 11 can be increased to improve the bonding force and reduce the resistance at the contact area.

[0057] The first electrode tab 11 and the first current collecting plate 30 may be bonded together by, for example, laser welding. The laser welding may be performed by partially melting a base material of the first current collecting plate 30, or may be performed with solder for welding interposed between the first current collecting plate 30 and the first electrode tab 11. In this case, the solder may have a lower melting point than the first current collecting plate 30 and the first electrode tab 11.

[0058] 2 and 3, the second current collecting plate 40 may be attached to the lower surface of the jelly roll 10. In this case, one surface of the second current collecting plate 40 may be attached to the second electrode tab 12 of the jelly roll 10 by welding, and the other surface may be attached to the inner bottom surface of the battery can 20 by welding. The attachment structure of the second current collecting plate 40 and the second electrode tab 12 attached to the lower surface of the jelly roll 10 is substantially the same as that of the second current collecting plate 40 attached to the upper surface of the jelly roll 10 described above.

[0059] 3 and 4, the cylindrical battery cell 1 according to an embodiment of the present invention includes an insulating shrink tube 50. The insulating shrink tube 50 may include a shrinkable material. Thus, when the insulating shrink tube 50 encloses the jelly roll 10 and the first current collecting plate 30 and then shrinks, the insulating shrink tube 50 may be closely attached and fixed to the jelly roll 10 and the first current collecting plate 30. Thus, insulation may be reliably ensured.

[0060] For example, the insulating shrink tube 50 may include a heat-shrinkable material that shrinks when heat is applied. For example, the insulating shrink tube 50 may include polyethylene terephthalate (PET) having heat shrinkability. However, the material of the insulating shrink tube 50 is not limited thereto, and any material that can shrink when heated without losing insulation properties can be used for the insulating shrink tube 50 of the present invention.

[0061] Meanwhile, the insulating shrink tube 50 may be shrunk by heat within a predetermined temperature range. For example, the predetermined temperature range may be a temperature range including a temperature range formed by heat generated inside a secondary battery during charging and discharging of the secondary battery.

[0062] The insulating shrink tube 50 may be made of a material that does not chemically react with the electrolyte contained in the battery can 20. For example, the insulating shrink tube 50 may include polyethylene terephthalate (PET), which does not chemically react with the electrolyte. However, the material of the insulating shrink tube 50 is not limited thereto, and any material that does not chemically react with the electrolyte can be used for the insulating shrink tube 50 of the present invention.

[0063] 3, the insulating shrink tube 50 includes a first cover portion 51 and a second cover portion 52. More specifically, the insulating shrink tube 50 may include the first cover portion 51 covering at least a portion of the first current collecting plate 30, and the second cover portion 52 covering an upper end of an outer circumferential surface of the jelly roll 10.

[0064] 3 and 4, the second cover portion 52 is a portion extending in the vertical direction (direction parallel to the Z-axis) from an edge of the first cover portion 51. The first cover portion 51 is the entire portion of the insulating shrink tube 50 excluding the second cover portion 52. For example, in Figs. 3 and 4, the first cover portion 51 refers to a portion of the insulating shrink tube 50 that extends in the horizontal direction (direction parallel to the XY plane).

[0065] The first cover part 51 covers at least a portion of the first current collecting plate 30. For example, the first cover part 51 may cover a peripheral portion of an upper surface of the first current collecting plate 30. Also, the first cover part 51 may cover a portion of the first electrode tab 11 that is not covered by the first current collecting plate 30. And, the second cover part 52 covers an upper end of an outer circumferential surface of the jelly roll 10. The first cover part 51 may be connected to the second cover part 52.

[0066] 3, the radial extension length D1 of the first cover part 51 may be greater than or equal to the press-in depth B of the beading part 21 formed in the battery can 20. Here, the radial direction refers to the radial direction of the jelly roll 10. This reliably prevents electrical contact between the battery can 20 having the second polarity and the first current collecting plate 30 having the first polarity, thereby ensuring the safety of the battery.

[0067] 3, the extension length D2 of the second cover part 52 may be configured to be greater than or equal to the extension length T of the first electrode tab 11. Thus, the second cover part 52 may cover the first electrode tab 11 so that the first electrode tab 11 is not exposed to a sidewall side (inner peripheral surface side) of the battery can 20. With this structure, electrical contact between the battery can 20 having the second polarity and the first electrode tab 11 having the first polarity is prevented. Therefore, the extension length D2 of the second cover part 52 must be at least equal to the extension length T of the first electrode tab 11.

[0068] Meanwhile, for reliable insulation, the extension length D2 of the second cover part 52 may be formed slightly longer than the extension length T of the first electrode tab 11. In this case, the second cover part 52 may cover the entire area corresponding to the non-coated part (the part where the electrode active material is not applied) and part of the area corresponding to the coated part (the part where the electrode active material is applied) along the height direction (direction parallel to the Z-axis) of the jelly roll 10.

[0069] FIG. 6 is a view showing a cylindrical battery cell according to another embodiment of the present invention, and FIGS. 7 to 9 are views showing a cylindrical battery cell according to yet another embodiment of the present invention.

[0070] The cylindrical battery cell 1 according to the embodiment of Figures 6 to 9 is similar to the cylindrical battery cell 1 according to the embodiment of Figures 3 and 4 described above, so we will omit redundant descriptions of configurations that are substantially the same or similar to those of the above-mentioned embodiments, and will focus on the differences from the above-mentioned embodiments below.

[0071] 6, the first cover part 51 of the insulating shrink tube 50 may cover most of the area of ​​the upper end of the jelly roll 10. That is, the first cover part 51 may cover the remaining area except for the part of the upper surface where the first current collecting plate 30 and the lead L are coupled. This structure can further reduce the risk of short circuit caused by contact between the first current collecting plate 30 and the inner surface of the battery can 20. In addition, this structure can prevent the insulating shrink tube 50 from coming off the first current collecting plate 30 and the insulating performance of the cylindrical battery cell 1 from deteriorating by increasing the coupling area between the insulating shrink tube 50 and the first current collecting plate 30.

[0072] Referring to FIG. 7, in the cylindrical battery cell 1 according to the embodiment of the present invention, the diameter of the first current collecting plate 30 may be smaller than the diameter of the jelly roll 10. In other words, the radius R30 of the first current collecting plate 30 may be smaller than the radius R10 of the jelly roll 10. In this way, even if the diameter of the first current collecting plate 30 is smaller than the diameter of the jelly roll 10, the electrical connection between the first current collecting plate 30 and the first electrode tab 11 can be maintained. In this way, due to the structure in which the diameter of the first current collecting plate 30 is smaller than the diameter of the jelly roll 10, the electrolyte can be smoothly injected from the area not covered by the first current collecting plate 30 on the upper surface of the jelly roll 10. Therefore, the ease of electrolyte injection and impregnation are improved. In addition, when the diameter of the first current collecting plate 30 is smaller than the diameter of the jelly roll 10, the possibility of contact between the battery can 20 and the first current collecting plate 30 due to the indentation of the battery can 20 due to the formation of the beading portion 21 can be eliminated. Therefore, in this case, the total height of the jelly roll 10 can be increased within the battery can 20, thereby improving the energy density. The difference between the radius R10 of the jelly roll 10 and the radius R30 of the first current collecting plate 30 can be, for example, the same as or greater than the press-in depth of the beading portion 21.

[0073] 7, the insulating shrink tube 50 may cover the upper end region of the outer circumferential surface of the jelly roll 10, a portion of the upper surface of the first current collecting plate 30, and the upper surface of the jelly roll 10 not covered by the first current collecting plate 30. More specifically, the first cover part 51 may cover both the first electrode tab 11 and the first current collecting plate 30. That is, the first cover part 51 may cover the upper surface of the first current collecting plate 30 and the upper surface of the jelly roll 10 not covered by the first current collecting plate 30. Therefore, the first cover part 51 may have a stepped shape in the area where the first current collecting plate 30 and the first electrode tab 11 contact each other. In other words, the first cover part 51 may cover at least a portion of the upper surface of the first current collecting plate 30 including the peripheral region and the outer circumferential surface. Meanwhile, the second cover part 52 may cover the upper end of the outer circumferential surface of the jelly roll 10.

[0074] Referring to FIG. 8, the jelly roll 10 of the present invention may include a first region A1 in which the first electrode tabs 11 have a first length T1, and a second region A2 located on the outer periphery of the first region A1, in which the first electrode tabs 11 have a second length T2.

[0075] Referring to FIG. 8, the first length T1 may be longer than the second length T2. At least a portion of the second region A2 may be located under the beading portion 21 formed on the battery can 20. When the length of the first electrode tab 11 located under the beading portion 21 is shorter than the length of the first electrode tab 11 in other regions, the risk of short circuit due to contact between the beading portion 21 and the first electrode tab 11 may be reduced. The first current collecting plate 30 may cover the first region A1 of the jelly roll 10. That is, the diameter of the first current collecting plate 30 may be approximately equal to the radial length of the first region A1. Alternatively, although not shown, the radius of the first current collecting plate 30 may be configured to be smaller than the distance from the winding center C of the jelly roll 10 to the boundary point between the first region A1 and the second region A2.

[0076] The first cover part 51 may cover the second region A2 of the jelly roll 10 and the first current collecting plate 30. Referring to Fig. 8, the first cover part 51 may cover the first electrode tab 11 located in the second region A2 of the jelly roll 10, at least a portion of an upper surface of the first current collecting plate 30 including a peripheral region, and an outer circumferential surface of the first electrode tab 11 located in the first region A1. And, the second cover part 52 may cover the outer circumferential surface of the first electrode tab 11 located in the second region A2.

[0077] The distance from the outer circumferential surface of the battery can 20 to the boundary point between the first region A1 and the second region A2 may be greater than or equal to the pressing depth of the beading portion 21 formed by pressing around the outer circumferential surface of the battery can 20. In this case, the formation of the beading portion 21 significantly reduces the risk of contact between the battery can 20 and the first electrode tab 11 and the battery can 20 and the first current collecting plate 30. As a result, the total height of the jelly roll 10 can be increased.

[0078] Meanwhile, in another aspect, the beading portion 21 may be formed below or on the same line as the first current collecting plate 30 due to an increase in the total height of the jelly roll 10. More specifically, the beading portion 21 may be located below or at approximately the same height as the bottom end of the first current collecting plate 30 along the height direction (direction parallel to the Z-axis) of the cylindrical battery cell 1. With such a structure in which the beading portion 21 is formed below or on the same line as the first current collecting plate 30, the dead space inside the battery can 20 may be significantly reduced. Therefore, the energy density of the battery may be increased.

[0079] In particular, when the beading portion 21 is located lower in the height direction of the cylindrical battery cell 1 than the bottom end of the first current collecting plate 30, the total height of the jelly roll 10 can be maximized, thereby minimizing the dead space formed between the upper cap 60 and the first current collecting plate 30. As a result, the improvement of the energy density of the battery can be maximized.

[0080] The first electrode tab 11 located in the second region A2 of FIG. 8 may be omitted. This is shown in detail in FIG. 9. Referring to FIG. 9, the jelly roll 10 does not include the first electrode tab 11 in the second region A2. In this case, the total height of the jelly roll 10 can be further increased compared to the embodiment shown in FIG. 8. As a result, the dead space inside the battery can 20 is reduced compared to the case of FIG. 8. Therefore, the energy density of the battery can be maximized.

[0081] Meanwhile, in Figs. 3, 4 and 6 to 9, the thickness of the insulating shrink tube 50 is shown thick for convenience of explanation, but in reality, the thickness of the insulating shrink tube 50 is very thin and almost like a film that occupies little space. As a result, the cylindrical secondary battery according to the present invention can further increase the energy density compared to a case in which a separate insulator is applied to prevent contact between the first current collecting plate 30 and the battery can 20 and between the first electrode tab 11 and the battery can 20. In addition, in the cylindrical secondary battery according to the present invention, the insulating shrink tube 50 is applied to the combination of the jelly roll 10 and the first current collecting plate 30, and the combination can be smoothly inserted into the battery can 20 after completing the insulation process by applying the insulating shrink tube 50 to the combination. As a result, the productivity in manufacturing the cylindrical battery cell 1 can be improved, and the risk of product defects is reduced in the process of inserting the combination of the jelly roll 10 and the first current collecting plate 30 into the battery can 20.

[0082] With further reference to FIG. 3, the cylindrical battery cell 1 according to one embodiment of the present invention includes a top cap 60.

[0083] The top cap 60 may be electrically connected to the first current collecting plate 30 and cover the opening. The top cap 60 is a part made of a conductive metal material and covers the opening at the top end of the battery can 20. The top cap 60 is electrically connected to the first electrode tab 11 of the jelly roll 10 and is electrically insulated from the battery can 20. Thus, the top cap 60 may function as a first electrode terminal of the cylindrical battery cell 1.

[0084] The top cap 60 may be provided on a beading portion 21 formed on the battery can 20. The top cap 60 may be fixed by forming a crimping portion 22. An airtight gasket 70 may be interposed between the top cap 60 and the crimping portion 22 of the battery can 20 to ensure airtightness of the battery can 20 and to electrically insulate the battery can 20 from the top cap 60.

[0085] The upper cap 60 may include a protrusion 61 formed by swelling upward from the center thereof. That is, the protrusion 61 may protrude upward to facilitate contact with an electrical connection component such as a bus bar.

[0086] 2 and 3, the cylindrical battery cell 1 according to an embodiment of the present invention may further include a connection plate 80.

[0087] The connecting plate 80 may be attached to a lower surface of the upper cap 60 and electrically connected to the lead L adjacent to the first current collecting plate 30. However, the connecting plate 80 may be omitted to reduce the internal space of the battery and increase the energy density, as shown in FIGS. 8 and 9.

[0088] FIG. 10 is a diagram for explaining a battery pack including the battery cell of FIG.

[0089] 10, a battery pack 3 according to an embodiment of the present invention includes a secondary battery assembly in which a plurality of cylindrical battery cells 1 according to an embodiment of the present invention are electrically connected as described above, and a pack housing 2 that accommodates the secondary battery assembly. For ease of illustration in the drawings, components such as bus bars and power terminals for electrical connection are omitted in the drawings of the present invention.

[0090] FIG. 11 is a diagram for explaining a vehicle including the battery pack of FIG.

[0091] 11, a vehicle V according to an embodiment of the present invention is, for example, a hybrid vehicle or an electric vehicle V, and includes a battery pack 3 according to an embodiment of the present invention. The vehicle V operates by receiving power from the battery pack 3 according to an embodiment of the present invention.

[0092] Although terms indicating directions such as up and down are used in this specification, it will be obvious to those skilled in the art that such terms indicate relative positions and are used merely for convenience of explanation, and may vary depending on the position of the object in question, the position of the observer, etc.

[0093] As described above, the present invention has been described using limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention belongs within the technical spirit of the present invention and the equivalent scope of the claims described below. [Explanation of symbols]

[0094] 3 Battery pack 2 Pack Housing 1 Cylindrical battery cell 10. Jelly Roll 11 First electrode tab 12 2nd electrode tab 20 Battery Can 21 Beading Section 22 Crimping section 30 First current collecting plate 40 Second current collecting plate 50 Insulating shrink tube 51 First cover part 52 Second cover part 60 Top Cap 61 Protrusion 70 Airtight Gasket 80 Connecting Plate L Lead C Winding center B Press-in depth H opening D1 Radial extension length of the first cover part D2 Extension length of the second cover R10 Jelly roll radius R30 Radius of first current collecting plate T Extension length of first electrode tab T1 First length T2 Second length A1 1st area A2 2nd area V Automobile

Claims

1. a jelly roll having a first electrode tab protruding upward and a second electrode tab protruding downward; a battery can that houses the jelly roll through an opening at an upper end and is electrically connected to the second electrode tab; a first current collecting plate coupled to the first electrode tab at an upper portion of the jelly roll; an insulating shrink tube including a first cover portion covering at least a portion of the first current collecting plate and a second cover portion covering an upper end of an outer circumferential surface of the jelly roll; a top cap electrically connected to the first current collecting plate and covering the opening; the diameter of the first current collecting plate is smaller than the diameter of the jelly roll; The first cover portion is connected to the second cover portion, The insulating shrink tube has a stepped shape, a cylindrical battery cell, wherein an inner end of the first cover portion of the insulating shrink tube is located inside a beading portion such that a radial extension length of the first cover portion is greater than a press-in depth of the beading portion formed by pressing in around an outer peripheral surface of the battery can.

2. A cylindrical battery cell as described in claim 1, wherein the first cover portion covers both the first electrode tab and the first collecting plate.

3. The jelly roll is 2. The cylindrical battery cell according to claim 1, wherein the first electrode tab includes a first region having a first length, and a second region located on an outer periphery of the first region, the first electrode tab having a second length.

4. The cylindrical battery cell according to claim 3 , wherein the first length is longer than the second length.

5. 5. The cylindrical battery cell of claim 4, wherein a distance from an outer peripheral surface of the battery can to a boundary point between the first region and the second region is greater than or equal to a pressing depth of a beading portion formed by pressing in around the outer peripheral surface of the battery can.

6. The beading portion is 6. The cylindrical battery cell of claim 5, located below a lowermost end of the first current collecting plate.

7. The first current collecting plate is The cylindrical battery cell of claim 3 , covering the first region of the jelly roll.

8. The first cover portion is 8. The cylindrical battery cell of claim 7, covering the second region of the jelly roll and the first current collecting plate.

9. The insulating shrink tube is 10. The cylindrical battery cell of claim 1, comprising a heat shrinkable material that shrinks upon application of heat.

10. The cylindrical battery cell comprises: The battery further includes an electrolyte solution contained inside the battery can, The insulating shrink tube is 10. The cylindrical battery cell of claim 1, wherein the material is chemically non-reactive with the electrolyte.

11. The extension length of the second cover portion is The cylindrical battery cell according to claim 1 , wherein the extension length of the first electrode tab is greater than or equal to the extension length of the second electrode tab.

12. 3. The cylindrical battery cell of claim 2, wherein a difference between a radius of the jelly roll and a radius of the first current collecting plate is equal to or greater than a pressing depth of a beading portion formed by pressing an outer circumferential surface of the battery can.

13. The cylindrical battery cell of claim 2 , wherein the first cover portion has a stepped shape in a region where the first current collecting plate and the first electrode tab contact each other.

14. The jelly roll is 2. The cylindrical battery cell according to claim 1, wherein the first electrode tab comprises a first region having a first length, and a second region located on an outer periphery of the first region and not including the first electrode tab.

15. A battery pack comprising at least one cylindrical battery cell of the substrate according to any one of claims 1 to 14.

16. A motor vehicle comprising at least one battery pack according to claim 15.

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