Cylindrical battery cells, battery packs containing them, and automobiles

Abstract

A cylindrical battery cell, a battery pack containing the same, and an automobile are disclosed. A cylindrical battery cell according to one embodiment of the present invention includes an electrode assembly having a central hole formed thereon, having a structure in which a positive electrode plate with a positive electrode tab, a negative electrode plate with a negative electrode tab, and a separator membrane interposed between the positive electrode plate and the negative electrode plate are wound in one direction, a cylindrical battery can in which the electrode assembly is housed and an electrolyte is injected, and an insulator having a central opening and positioned on the negative electrode tab side for electrical insulation, wherein at least a portion of the negative electrode tab rotates in response to changes in the electrode assembly during charging and discharging.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0104435, filed on August 9, 2023, and all the contents disclosed in the specification and drawings of the application are incorporated herein by reference.

[0002] The present invention relates to a cylindrical battery cell, a battery pack including the same, and a vehicle, and more particularly, to a cylindrical battery cell capable of preventing a short circuit by preventing the form collapse of an electrode assembly, a battery pack including the same, and a vehicle.

Background Art

[0003] Secondary batteries, which are easy to apply according to product groups and have electrical characteristics such as high energy density, are widely applied not only to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), etc. driven by an electric drive source.

[0004] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also are environmentally friendly in that no by-products are generated during energy use, and are attracting attention as a new energy source for improving energy efficiency.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such a unit secondary battery cell is about 2.5V to 4.5V.

[0006] If a higher output voltage is required, multiple battery cells can be connected in series to form a battery module or battery pack. Alternatively, multiple battery cells can be connected in parallel to form a battery module or battery pack depending on the required charge / discharge capacity. Therefore, the number of battery cells and the electrical connection configuration included in a battery module or battery pack can be set in various ways depending on at least one of the required output voltage and charge / discharge capacity.

[0007] In addition, cylindrical, prismatic, and pouch-type battery cells are known as secondary battery cells. In the case of cylindrical battery cells, an insulating separator membrane is interposed between the positive and negative electrodes, and this is wound up to form a jelly roll-shaped electrode assembly, which is then placed in a battery case together with the electrolyte to constitute the battery.

[0008] Figure 1 shows how the lengths of the positive and negative electrode plates of a conventional cylindrical battery cell change during repeated charging and discharging.

[0009] Normally, when a cylindrical battery cell is continuously charged and discharged, the length of the positive electrode plate 2 or negative electrode plate 4 of the electrode assembly 1 increases as the positive electrode plate 2 or negative electrode plate 4 repeatedly contracts and relaxes.

[0010] However, since the electrode assembly 1 is housed inside a cylindrical battery case (not shown in Figure 1, and may be made of metal), the external shape of the battery case does not change even if the length of the positive electrode plate 2 or the negative electrode plate 4 increases.

[0011] As a result, the shape of the positive electrode plate 2, separator membrane 3, or negative electrode plate 4 changes toward the center of the electrode assembly 1, as shown in Figure 1. However, if the positive electrode plate 2, separator membrane 3, or negative electrode plate 4 distort toward the center of the electrode assembly 1 in this way, causing the shape of the electrode assembly 1 to collapse, a short circuit may occur inside the cell, potentially leading to safety problems. [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention aims to provide a cylindrical battery cell capable of preventing the deformation of the electrode assembly during repeated charging and discharging of the cylindrical battery cell, a battery pack containing the same, and an automobile.

[0013] Another objective of the present invention is to provide a cylindrical battery cell capable of preventing short circuits, a battery pack including the same, and an automobile.

[0014] However, the technical problems that this invention aims to solve are not limited to those 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]

[0015] According to one aspect of the present invention, a cylindrical battery cell is provided, comprising an electrode assembly having a positive electrode plate with a positive electrode tab, a negative electrode plate with a negative electrode tab, and a separation membrane interposed between the positive electrode plate and the negative electrode plate, which is wound in one direction and has a central hole; a cylindrical battery can in which the electrode assembly is housed and an electrolyte is injected; and an insulator having a central opening, which is positioned on the negative electrode tab side and coupled to the electrode assembly, and is configured such that at least a portion of the negative electrode tab rotates in accordance with changes in the electrode assembly during charging and discharging.

[0016] In one embodiment, the negative electrode tab may include a first negative electrode tab fixed to the battery can, a second negative electrode tab located in the central hole of the electrode assembly and coupled to the electrode assembly, and rotating relative to the first negative electrode tab, and a coupling shaft coupled to the first negative electrode tab and the second negative electrode tab so that the second negative electrode tab is rotatable.

[0017] In one embodiment, the second negative electrode tab can rotate inside the central opening of the insulator.

[0018] In one embodiment, the second negative electrode tab can rotate as the length of at least one of the positive electrode plate and the negative electrode plate increases due to charging and discharging.

[0019] In one embodiment, the first negative electrode tab may include a fixed lateral tab formed laterally with respect to the arrangement of the battery can, and a fixed vertical tab extending from the fixed lateral tab so as to be bent, and located between the outermost part of the electrode assembly and the battery can.

[0020] In one embodiment, the second negative electrode tab may include a rotating lateral tab formed laterally with respect to the arrangement of the battery can, and a rotating vertical tab extending from the rotating lateral tab so as to bend and coupled to the electrode assembly at the central hole of the electrode assembly.

[0021] In one embodiment, an inner groove may be formed on the inside of the second negative electrode tab, and an outer projection may be formed on the outside of the coupling shaft, which is provided to contact the inner groove and move in only one direction along the inner groove.

[0022] In one embodiment, the inner groove includes a first line formed at an inclination from an arbitrary point, and a second line formed at an inclination toward the first line from a point opposite to the arbitrary point so as to be in contact with the first line, wherein the inclination angle of the first line and the inclination angle of the second line may be different.

[0023] In one embodiment, the inner groove includes a first line formed at an inclination from an arbitrary point, and a second line formed at an inclination toward the first line from a point opposite to the arbitrary point so as to be in contact with the first line, wherein the lengths of the first line and the second line may be different.

[0024] In one embodiment, an inner groove is formed inside the central opening of the insulator, and the second negative electrode tab may be formed to contact the inner groove and move along the inner groove in only one direction.

[0025] In one embodiment, the inner groove includes a first line formed to be inclined from an arbitrary point, and a second line formed to be inclined toward the first line so as to be in contact with the first line from an opposite point of the arbitrary point, and the inclination angle of the first line and the inclination angle of the second line may be different.

[0026] In one embodiment, the inner groove includes a first line formed to be inclined from an arbitrary point, and a second line formed to be inclined toward the first line so as to be in contact with the first line from an opposite point of the arbitrary point, and the length of the first line and the length of the second line may be different.

[0027] According to another aspect of the present invention, a battery pack including at least one of the above-described cylindrical battery cells is provided, and further, an automobile including at least one of the above-described cylindrical battery cells may be provided.

Advantages of the Invention

[0028] An embodiment of the present invention is configured such that at least a part of the negative electrode tab rotates, and it is possible to prevent the form collapse of the electrode assembly during charge and discharge repetition of the cylindrical battery cell.

[0029] Also, thereby, it is possible to prevent the occurrence of a short circuit in the cylindrical battery cell.

[0030] However, the effects obtained from the present invention are not limited to the above-described effects, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Brief Description of the Drawings

[0031] [Figure 1] It is a diagram showing a state in which changes have occurred in the lengths of the positive electrode plate and the negative electrode plate of the electrode assembly during charge and discharge repetition of a conventional cylindrical battery cell. [Figure 2] It is a cross-sectional view of a cylindrical battery cell according to a first embodiment of the present invention. [Figure 3] This is a schematic perspective view showing how the coupling shaft is connected to the first negative electrode tab and the second negative electrode tab of the negative electrode tab in a cylindrical battery cell according to the first embodiment of the present invention. [Figure 4] Figure 3 shows how the first negative electrode tab of the negative electrode tab rotates relative to the second negative electrode tab. [Figure 5] This is a schematic perspective view showing the first negative electrode tab and the second negative electrode tab of a cylindrical battery cell according to a second embodiment of the present invention. [Figure 6] This is a schematic perspective view showing the coupling axis of the negative electrode tab in a cylindrical battery cell according to a second embodiment of the present invention. [Figure 7] This is a schematic perspective view showing how the coupling shaft is connected to the first negative electrode tab and the second negative electrode tab of the negative electrode tab in a cylindrical battery cell according to a second embodiment of the present invention. [Figure 8] This figure shows how the first negative electrode tab of the negative electrode tab rotates relative to the second negative electrode tab inside the central opening of the insulator in a cylindrical battery cell according to a second embodiment of the present invention. [Figure 9] This figure shows an insulator in a cylindrical battery cell according to a third embodiment of the present invention, in which an inner groove is formed in the central opening. [Figure 10] This figure schematically shows how the negative electrode tab is coupled to the inner groove of the central opening of the insulator in a cylindrical battery cell according to a third embodiment of the present invention. [Figure 11] Figure 10 shows how the first negative electrode tab of the negative electrode tab rotates relative to the second negative electrode tab. [Figure 12] This figure shows an insulator according to a modified embodiment of the insulator shown in Figure 9. [Figure 13] This figure schematically shows the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention. [Figure 14] This is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention. [Modes for carrying out the invention]

[0032] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner appropriate to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concepts of terms in order to best describe the invention. Accordingly, it should be understood that the embodiments and configurations shown in the drawings described herein are merely the most preferred embodiments of the present invention and do not represent the entirety of the technical idea of ​​the present invention, and that there may be a variety of equivalents and modifications that can be substituted therein at the time of this application.

[0033] The size of each component or specific part of a component in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity and ease of explanation. Therefore, the size of each component may not fully reflect its actual size. Specific descriptions of known functions or configurations related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention.

[0034] As used herein, the terms “joining” or “connecting” include not only cases where one member is directly joined or directly connected to another member, but also cases where one member is indirectly joined or indirectly connected to another member via a connecting member.

[0035] Figure 2 is a cross-sectional view of a cylindrical battery cell according to the first embodiment of the present invention, Figure 3 is a schematic diagram showing how the coupling shaft is connected to the first negative electrode tab and the second negative electrode tab of the negative electrode tab in the cylindrical battery cell according to the first embodiment of the present invention, and Figure 4 is a diagram showing how the first negative electrode tab of the negative electrode tab rotates relative to the second negative electrode tab in Figure 3.

[0036] Referring to Figure 2, the cylindrical battery cell 10 according to the first embodiment of the present invention includes an electrode assembly 100, a battery can 200, and an insulator 400.

[0037] Referring to Figure 2, the electrode assembly 100 has a structure in which a positive electrode plate 110 equipped with a positive electrode tab 500, a negative electrode plate 120 equipped with a negative electrode tab 600, and a separation membrane 130 interposed between the positive electrode plate 110 and the negative electrode plate 120 are wound in one direction. A central hole 140 is formed in the center of the electrode assembly 100, and it can be formed in the shape of a jelly roll.

[0038] For example, the electrode assembly 100 can be manufactured by winding up a laminate formed by sequentially stacking a negative electrode plate 120, a separator membrane 130, a positive electrode plate 110, and another separator membrane 130 at least once. Here, the positive electrode plate 110 and the negative electrode plate 120 can be formed in sheet form.

[0039] That is, the electrode assembly 100 to be applied to this embodiment may be a winding type electrode assembly 100. In this case, the outer surface of the electrode assembly 100 may be further provided with a separation film (not shown) for insulation from the battery can 200. That is, the electrode assembly 100 may have any known winding structure in the relevant art without limitation.

[0040] The positive electrode plate 110 has a positive electrode active material coated on one or both sides. The positive electrode plate 110 is equipped with a positive electrode tab 500. The negative electrode plate 120 has a negative electrode active material coated on one or both sides. The negative electrode plate 120 is equipped with a negative electrode tab 600. A detailed explanation of the negative electrode tab 600 will be given later.

[0041] Furthermore, the positive electrode active material coated on the positive electrode plate 110 and the negative electrode active material coated on the negative electrode plate 120 can be any active material known in the industry without restriction.

[0042] The separation membrane 130 can be made from porous polymer films, such as ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, or ethylene / methacrylate copolymers, either alone or in a laminated configuration.

[0043] As another example, the separation membrane 130 may be made of a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0044] At least one surface of the separation membrane 130 may include a coating layer of inorganic particles. Furthermore, the separation membrane 130 itself may consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound to a binder such that interstitial volumes exist between adjacent particles.

[0045] Referring to Figure 2, the electrode assembly 100 is housed in the battery can 200 and an electrolyte solution is injected into it. For example, the battery can 200 is formed in a cylindrical shape, and the electrode assembly 100 is housed inside the battery can 200, and can be electrically connected to the negative electrode plate 120 of the electrode assembly 100. As a result, the battery can 200 can have the same polarity as the negative electrode plate 120, i.e., a negative electrode.

[0046] Here, the diameter of the battery casing 200 is formed to be larger than the diameter of the electrode assembly 100. The battery casing 200 may be made of a conductive material such as metal. The material of the battery casing 200 may be a conductive metal, such as aluminum, steel, or stainless steel, but is not limited to these.

[0047] Insulator 400 is coupled to the electrode assembly 100 for electrical insulation. In Figure 2, insulator 400 is coupled to the bottom of the electrode assembly 100. Insulator 300 is coupled to the electrode assembly 100 for electrical insulation. In Figure 2, insulator 300 is coupled to the top of the electrode assembly 100.

[0048] Insulator 300 is positioned on the positive electrode tab 500 side and coupled to the electrode assembly 100, while insulator 400 is positioned on the negative electrode tab 600 side and coupled to the electrode assembly 100. For the sake of clarity, the following explanation will focus on insulator 400, which is positioned on the negative electrode tab 600 side and coupled to the electrode assembly 100. However, any information relating to insulator 400 that is also relating to insulator 300 will be replaced by the information relating to insulator 400.

[0049] The insulator 400 can be formed in a shape corresponding to the cross-sectional shape of the jelly roll-type electrode assembly 100. For example, if the cross-section of the jelly roll-type electrode assembly 100 is circular, the shape of the insulator 400 may also be circular. The insulator 400 may have, for example, a circular central opening 410. Similarly, the insulator 300 may have, for example, a circular central opening 310.

[0050] The insulator 400 may include, for example, an elastic material. This allows the insulator 400 to absorb the shock when vibration or external shock is applied to the cylindrical battery cell 10, by compressing elastically and then returning to its original state. This minimizes damage to the internal components of the battery cell even when vibration or external shock is applied to the battery cell.

[0051] The insulator 400 may consist of a material having insulating properties. Preferably, the insulator 400 may include, but is not limited to, an insulating polymer material. For example, the insulator 400 may be made from polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polypropylene (PP).

[0052] In the first embodiment of the present invention, the cylindrical battery cell 10 is configured such that at least a portion of the negative electrode tab 600 rotates when, for example, the length or shape of the electrode assembly 100 changes, in order to prevent deformation of the electrode assembly 100 and to prevent short circuits of the cylindrical battery cell 10.

[0053] As mentioned above, when the cylindrical battery cell 10 is continuously charged and discharged, the positive electrode plate 110 or the negative electrode plate 120 repeatedly contracts and relaxes, causing the length of the positive electrode plate 110 or the negative electrode plate 120 to increase. Since the electrode assembly 100 is housed inside the cylindrical battery can 200, even if the length of the positive electrode plate 110 or the negative electrode plate 120 increases, its shape does not change on the outside of the battery can 200.

[0054] In this case, if at least a portion of the negative electrode tab 600 is configured to rotate, the positive electrode plate 110 or the negative electrode plate 120 will not wrinkle toward the center even if the length of the positive electrode plate 110 or the negative electrode plate 120 increases during charging and discharging.

[0055] In other words, as shown in Figure 1, in the case of a conventional cylindrical battery cell, even if the positive electrode plate 2 or the negative electrode plate 4 is stretched by force during charging and discharging, the negative electrode tab does not move because it is fixed to the battery can. As a result, wrinkles form on the positive electrode plate 2 or the negative electrode plate 4 from the part receiving the force toward the central hole of the electrode assembly 1.

[0056] However, in the cylindrical battery cell 10 according to the first embodiment of the present invention, when the positive electrode plate 110 or the negative electrode plate 120 is stretched by force during charging and discharging, at least a part of the negative electrode tab 600 is not fixed and rotates, so that the positive electrode plate 110 or the negative electrode plate 120 does not wrinkle toward the central hole 140 of the electrode assembly 100.

[0057] In other words, in the first embodiment of the present invention, the force generated during charging and discharging is converted into a rotational force of the negative electrode tab 600, which does not cause the shape of the electrode assembly 100 to collapse, thereby preventing a short circuit of the cylindrical battery cell 10.

[0058] Referring to Figures 2 and 3, the negative electrode tab 600 may be configured to include a first negative electrode tab 610, a second negative electrode tab 620, and a coupling shaft 630.

[0059] The first negative electrode tab 610 is fixed to the battery can 200. There are various ways in which the first negative electrode tab 610 is fixed to the battery can 200; for example, it can be fixed by welding.

[0060] The first negative electrode tab 610 may include a fixed horizontal tab 611 and a fixed vertical tab 612.

[0061] The fixed lateral tab 611 is formed laterally based on the arrangement of the battery can 200. For example, if the battery can 200 is arranged as shown in Figure 2, the fixed lateral tab 611 may be positioned horizontally at the bottom of the battery can 200.

[0062] The fixed vertical tab 612 may extend from the fixed horizontal tab 611 in a way that allows it to be folded, and may be positioned between the outermost part of the electrode assembly 100 and the battery can 200. The fixed vertical tab 612 may extend from the fixed horizontal tab 611 by folding, for example, vertically, but is not necessarily limited to vertically.

[0063] The first negative electrode tab 610 is then joined to at least one of the bottom and side surfaces of the battery can 200. Specifically, the fixing horizontal tab 611 can be joined to the bottom of the battery can 200 by welding or the like, and the fixing vertical tab 612 can be joined to the side surface of the battery can 200 by welding or the like.

[0064] The second negative electrode tab 620 is located in the central hole 140 of the electrode assembly 100 and is coupled to the electrode assembly 100, and is configured to rotate relative to the first negative electrode tab 610. That is, the second negative electrode tab 620 is provided so as to be rotatable with the coupling shaft 630 as the axis of rotation.

[0065] Furthermore, since one side of the second negative electrode tab 620 is connected to the electrode assembly 100, when the charging and discharging of the cylindrical battery cell 10 increases the length of at least one of the positive electrode plate 110 and the negative electrode plate 120, and a force acts on the electrode assembly 100, that force causes the second negative electrode tab 620 to rotate.

[0066] Furthermore, as the second negative electrode tab 620 rotates, the force acting on the electrode assembly 100 is converted into a rotational force, as described above, which prevents the electrode assembly 100 from collapsing.

[0067] Referring to Figures 2 and 3, the second negative electrode tab 620 may be configured to rotate inside the central opening 410 of the insulator 400 (see Figure 8 in the second embodiment). That is, the diameter of the central opening 410 of the insulator 400 may be made larger than the rotational diameter of the second negative electrode tab 620 so that it does not interfere with the insulator 400 when the second negative electrode tab 620 rotates.

[0068] The second negative electrode tab may include a rotating horizontal tab 621 and a rotating vertical tab 622.

[0069] The rotating lateral tab 621 is formed laterally based on the arrangement of the battery can 200. For example, if the battery can 200 is arranged as shown in Figure 2, the rotating lateral tab 621 may be positioned horizontally at the bottom of the battery can 200.

[0070] The rotating horizontal tab 621 rotates together with the rotating vertical tab 622 by increasing the length of at least one of the positive plate 110 and the negative plate 120.

[0071] The rotating vertical tab 622 extends from the rotating horizontal tab 621 so as to bend and is coupled to the electrode assembly 100 at the central hole 140 of the electrode assembly 100. The rotating vertical tab 622 may, but is not necessarily limited to, extend from the rotating horizontal tab 621 by bending, for example, vertically.

[0072] The rotating vertical tab 622 also rotates together with the rotating horizontal tab 621 by increasing the length of at least one of the positive plate 110 and the negative plate 120.

[0073] The coupling shaft 630 is coupled to the first negative electrode tab 610 and the second negative electrode tab 620 so that the second negative electrode tab 620 is rotatable. The coupling shaft 630 is then coupled and fixed to the battery can 200 in a variety of ways. For example, it may be coupled by welding, but is not limited to this. The coupling shaft 630 functions as a rotation axis with respect to the second negative electrode tab 620.

[0074] Referring to Figure 2, the upper cap 700 may be configured to be electrically connected to the positive electrode tab 500 and electrically insulated from the battery can 200. This allows the upper cap 700 to function as the positive electrode terminal of the cylindrical battery cell 10. The upper cap 700 may be made of a conductive metallic material and configured to cover the upper end opening of the battery can 200.

[0075] The upper cap 700 is provided on the beading portion 210 formed on the battery can 200 and can be fixed by forming a crimping portion 220. Here, in order to ensure the airtightness of the battery can 200 and to provide electrical insulation between the battery can 200 and the upper cap 700, a sealing gasket 230 may be interposed between the upper cap 700 and the crimping portion 220 of the battery can 200.

[0076] The beading portion 210 is formed by press-fitting the outer circumferential surface of the battery can 200 inward. The beading portion 210 supports the electrode assembly 100, which has a size approximately corresponding to the width of the battery can 200, to prevent it from coming out from the top of the battery can 200, and can also function as a support to which the upper cap 700 is provided. The beading portion 210 can also support the outer circumferential surface of the sealing gasket 230.

[0077] The crimping portion 220 extends inward and is bent to surround and secure the end of the upper cap 700 together with the sealing gasket 230. Here, for example, referring to Figure 2, the crimping portion 220 may be formed on the upper part of the battery can 200 based on the arrangement of the battery can 200. And, as shown in Figure 2, the crimping portion 220 may be formed on the upper part of the beading portion 210. However, this is only one embodiment, and the positions of the crimping portion 220 and the beading portion 210 are not limited to this.

[0078] Furthermore, the present invention does not exclude cases in which the battery can 200 does not have at least one of the beading portion 210 and the crimping portion 220. In the present invention, if the battery can 200 does not have at least one of the beading portion 210 and the crimping portion 220, fixing the electrode assembly 100, or fixing the upper cap 700, or sealing the battery can 200 can be achieved by at least one of the following: additional application of a component that can function as a stopper to the electrode assembly 100, additional application of a structure on which the upper cap 700 may be provided, or welding of the battery can 200 and the upper cap 700.

[0079] Referring to Figure 2, the crimping portion 220 is formed on the upper part of the beading portion 210. The crimping portion 220 has a shape that extends and bends to surround the periphery of the upper cap 700 which is positioned on the upper part of the beading portion 210. The upper cap 700 is fixed to the beading portion 210 by the shape of the crimping portion 220 which is bent in this way.

[0080] Although not shown in the diagram, a vent notch (not shown) may be formed that causes the upper cap 700 to rupture if the internal pressure of the battery can 200 exceeds a critical value.

[0081] Figure 5 is a schematic perspective view showing the first and second negative electrode tabs of a negative electrode tab in a cylindrical battery cell according to a second embodiment of the present invention; Figure 6 is a schematic perspective view showing the coupling axis of the negative electrode tab in a cylindrical battery cell according to a second embodiment of the present invention; Figure 7 is a schematic perspective view showing how the coupling axis is coupled to the first and second negative electrode tabs of a negative electrode tab in a cylindrical battery cell according to a second embodiment of the present invention; and Figure 8 is a diagram showing how the second negative electrode tab of a negative electrode tab rotates relative to the first negative electrode tab inside the central opening of the insulator in a cylindrical battery cell according to a second embodiment of the present invention.

[0082] The second embodiment of the present invention differs from the first embodiment in that an inner groove 625 is formed on the second negative electrode tab 620 and an outer projection 631 is formed on the coupling shaft 630. Here, the parts that are common with the parts described in the first embodiment will be described in the description of the first embodiment above. Also, the parts of the second embodiment that are applicable to the first embodiment can be applied to the first embodiment.

[0083] Referring to Figure 5, an inner groove 625 is formed on the inside of the second negative electrode tab 620. Here, the inner groove 625 can be formed in various ways.

[0084] For example, the inner groove 625 may include a first line 626 and a second line 627. The first line 626 is formed to be inclined from any point. The second line 627 is formed to be inclined toward the first line 626 from a point opposite to any point so as to be in contact with the first line 626.

[0085] Here, the inclination angle of the first line 626 and the inclination angle of the second line 627 may be formed to have different inclination angles.

[0086] Alternatively, the lengths of the first line 626 and the second line 627 may be formed to be different lengths.

[0087] Referring to Figure 6, an external projection 631 may be formed on the outside of the coupling axis 630. In Figure 6, only one external projection 631 is formed, but there may be multiple external projections 631.

[0088] Referring to Figure 7, the outer projection 631 is formed to contact the inner groove 625 and move along the inner groove 625 in only one direction.

[0089] Specifically, referring to Figures 7 and 8, the outer projection 631 formed on the outside of the coupling shaft 630 moves in only one direction along the inner groove 625 formed on the inside of the second negative electrode tab 620, preventing movement in the opposite direction.

[0090] The charging and discharging of the cylindrical battery cell 10 increases the length of at least one of the positive electrode plate 110 and the negative electrode plate 120, causing the second negative electrode tab 620 to rotate in only one direction, preventing deformation of the electrode assembly 100 and preventing a short circuit of the cylindrical battery cell 10.

[0091] Figure 9 shows an insulator with an inner groove formed in the central opening in a cylindrical battery cell according to a third embodiment of the present invention, Figure 10 is a schematic perspective view showing how the negative electrode tab is coupled to the inner groove of the central opening of the insulator in a cylindrical battery cell according to a third embodiment of the present invention, and Figure 11 shows how the first negative electrode tab of the negative electrode tab rotates relative to the second negative electrode tab in Figure 10.

[0092] The third embodiment of the present invention differs from the first or second embodiment in that an inner groove 411 is formed in the insulator 400. Here, the parts that are common with the parts described in the first or second embodiment are described in the first or second embodiment above. Alternatively, the parts of the third embodiment that are applicable to the first or second embodiment may be applied to the first or second embodiment.

[0093] Referring to Figure 9, an inner groove 411 is formed inside the central opening 410 of the insulator 400. Here, the inner groove 411 can be formed in various ways.

[0094] For example, the inner groove 411 may include a first line 412 and a second line 413. The first line 412 is formed at an incline from any point. The second line 413 is formed at an incline toward the first line 412 from a point opposite to any point so as to be in contact with the first line 412.

[0095] Here, the inclination angle of the first line 412 and the inclination angle of the second line 413 may be formed to have different inclination angles.

[0096] Alternatively, the lengths of the first line 412 and the second line 413 may be formed to be different lengths.

[0097] Referring to Figure 10, the second negative electrode tab 620 is formed to contact the inner groove 411 and move along the inner groove 411 in only one direction. That is, the side portion of the rotating lateral tab 621 of the second negative electrode tab 620 is configured to engage with the inner groove 411 of the central opening 410 of the insulator 400 and rotate. To achieve this, at least one side of the rotating lateral tab 621 of the second negative electrode tab 620 has a corner portion 629 that engages with the inner groove 411 of the insulator 400.

[0098] Furthermore, the corner portion 629 of the rotating lateral tab 621 of the second negative electrode tab 620 is formed to contact the inner groove 411 of the central opening 410 of the insulator 400 and move along the inner groove 411 in only one direction.

[0099] In other words, the corner portion 629 of the rotating lateral tab 621 of the second negative electrode tab 620 moves in only one direction along the inner groove 411 formed inside the central opening 410 of the insulator 400, preventing movement in the opposite direction.

[0100] As a result, the charging and discharging of the cylindrical battery cell 10 increases the length of at least one of the positive electrode plate 110 and the negative electrode plate 120, causing the second negative electrode tab 620 to rotate in only one direction, preventing deformation of the electrode assembly 100 and preventing a short circuit of the cylindrical battery cell 10.

[0101] Figure 12 shows an insulator according to a modified embodiment of the insulator in Figure 9.

[0102] Referring to Figure 12, in the case of the modified embodiment of insulator 400a, the length of the first line 412a is longer than in the case of Figure 9. That is, the length of the first line 412a of the inner groove 411a of insulator 400a in Figure 12 is longer than the length of the first line 412 of the inner groove 411 of insulator 400 in Figure 9. As a result, there is also a difference in the number of inner grooves 411 and 411a. Figure 12 is one modified embodiment of Figure 9, and there may be more variations in the modified embodiments of Figure 9.

[0103] Figure 13 is a schematic diagram showing the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention.

[0104] Referring to Figure 13, each embodiment of the present invention may include one or more cylindrical battery cells 10 according to one embodiment of the present invention as described above. The battery pack 20 may further include a pack housing 200 for housing the cylindrical battery cells 10, and various devices for controlling the charging and discharging of the cylindrical battery cells 10, such as a BMS, current sensor, fuse, etc.

[0105] Figure 14 is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention.

[0106] Referring to Figure 14, an automobile 30 according to one embodiment of the present invention may include one or more cylindrical battery cells 10 or battery packs 20 according to each of the embodiments described above. Here, the automobile 30 includes various types of automobiles that use electricity, such as electric vehicles or hybrid vehicles.

[0107] In this specification, terms indicating direction such as up, down, left, right, front, and back are used. However, such terms indicate relative positions and are for the sake of convenience of explanation only. It is obvious to those skilled in the art that these positions can change depending on the position of the object in question, the observer's position, and so on.

[0108] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and of course, various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims below by persons with ordinary skill in the art to which the present invention pertains. Therefore, the embodiments described above should be considered from an explanatory rather than restrictive viewpoint. That is, the true technical concept of the present invention is shown in the claims, and all differences within the equivalent scope thereto should be interpreted as being included in the present invention. [Industrial applicability]

[0109] The present invention relates to cylindrical battery cells, battery packs containing them, and automobiles, and is particularly applicable to the secondary battery industry.

Claims

1. An electrode assembly having a structure in which a positive electrode plate equipped with a positive electrode tab, a negative electrode plate equipped with a negative electrode tab, and a separation membrane interposed between the positive electrode plate and the negative electrode plate are wound in one direction, and a central hole is formed therein, A cylindrical battery can containing the electrode assembly and into which the electrolyte is injected, It includes an insulator having a central opening and positioned on the negative electrode tab side and coupled to the electrode assembly, A cylindrical battery cell configured such that at least a portion of the negative electrode tab rotates in response to changes in the electrode assembly during charging and discharging.

2. The aforementioned negative electrode tab is A first negative electrode tab fixed to the aforementioned battery can, A second negative electrode tab is located in the central hole of the electrode assembly and coupled to the electrode assembly, and rotates relative to the first negative electrode tab, A cylindrical battery cell according to claim 1, comprising a coupling shaft that connects to the first negative electrode tab and the second negative electrode tab so that the second negative electrode tab is rotatable.

3. The cylindrical battery cell according to claim 2, wherein the second negative electrode tab rotates inside the central opening of the insulator.

4. The cylindrical battery cell according to claim 2, wherein the second negative electrode tab rotates due to an increase in the length of at least one of the positive electrode plate and the negative electrode plate during charging and discharging.

5. The first negative electrode tab is A fixed lateral tab formed laterally based on the arrangement of the aforementioned battery can, A cylindrical battery cell according to claim 2, comprising a fixed vertical tab extending from the fixed horizontal tab so as to be bent, and located between the outermost part of the electrode assembly and the battery can.

6. The second negative electrode tab is A rotating lateral tab formed laterally based on the arrangement of the aforementioned battery can, A cylindrical battery cell according to claim 2, comprising: a rotating vertical tab extending from the rotating horizontal tab so as to be bendable and coupled to the electrode assembly at the central hole of the electrode assembly.

7. An inner groove is formed on the inside of the second negative electrode tab. The cylindrical battery cell according to claim 2, wherein an outer projection is formed on the outer side of the coupling shaft, which is provided to contact the inner groove and move in only one direction along the inner groove.

8. The inner groove is A first line formed by sloping from an arbitrary point, The set includes a second line formed at an angle toward the first line from a point opposite to the aforementioned arbitrary point so as to be in contact with the first line, The cylindrical battery cell according to claim 7, wherein the inclination angle of the first line and the inclination angle of the second line are different.

9. The inner groove is A first line formed by sloping from an arbitrary point, The set includes a second line formed at an angle toward the first line from a point opposite to the aforementioned arbitrary point so as to be in contact with the first line, The cylindrical battery cell according to claim 7, wherein the length of the first line and the length of the second line are different.

10. An inner groove is formed on the inside of the central opening of the insulator. The cylindrical battery cell according to claim 2, wherein the second negative electrode tab is formed to contact the inner groove and move along the inner groove in only one direction.

11. The inner groove is A first line formed by sloping from an arbitrary point, The set includes a second line formed at an angle toward the first line from a point opposite to the aforementioned arbitrary point so as to be in contact with the first line, The cylindrical battery cell according to claim 10, wherein the inclination angle of the first line and the inclination angle of the second line are different.

12. The inner groove is A first line formed by sloping from an arbitrary point, The set includes a second line formed at an angle toward the first line from a point opposite to the aforementioned arbitrary point so as to be in contact with the first line, The cylindrical battery cell according to claim 10, wherein the length of the first line and the length of the second line are different.

13. A battery pack comprising at least one cylindrical battery cell as described in any one of claims 1 to 12.

14. An automobile comprising at least one cylindrical battery cell as described in any one of claims 1 to 12.

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