Batteries, battery packs including the same, and automobiles

Abstract

According to one embodiment of the present invention, there is provided a battery comprising: an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed therebetween around a winding shaft, the first electrode and the second electrode each including a first uncoated portion and a second uncoated portion that are not coated with an active material layer along a winding direction; a battery housing that receives the electrode assembly through an opening formed on one side; a cap having a venting portion, covering the opening, and electrically connected to the battery housing and the first uncoated portion; and a battery terminal that penetrates one side of the battery housing and is electrically connected to the second uncoated portion.

Description

[Technical Field]

[0001] The present invention relates to a battery, a battery pack including the same, and a vehicle. More specifically, the present invention relates to a battery having a structure in which a cap covering one side opening of a battery housing can simultaneously function as a venting device and a CID (Current Interrupt Device), a battery pack including the same, and a vehicle.

[0002] This application claims priority to Korean Patent Application No. 10-2021-0022877 filed on February 19, 2021, Korean Patent Application No. 10-2021-0022894 filed on February 19, 2021, Korean Patent Application No. 10-2021-0024424 filed on February 23, 2021, Korean Patent Application No. 10-2021-0131215 filed on October 1, 2021, and Korean Patent Application No. 10-2021-0154307 filed on November 10, 2021, and the contents disclosed in the specifications and drawings of those applications are incorporated herein in their entirety. [Background technology]

[0003] Generally, when manufacturing a battery pack using cylindrical batteries, a plurality of cylindrical batteries are arranged upright in a housing, and the upper and lower ends of the cylindrical batteries are used as positive and negative terminals, respectively, to electrically connect the plurality of cylindrical batteries to each other.

[0004] This is because, in a cylindrical battery, the negative electrode uncoated portion of the electrode assembly housed inside the battery housing extends downward to be electrically connected to the bottom surface of the battery housing, and the positive electrode uncoated portion extends upward to be electrically connected to the cap. That is, in a cylindrical battery, the bottom surface of the battery housing is generally used as the negative electrode terminal, and the cap covering the top open end of the battery housing is generally used as the positive electrode terminal.

[0005] However, when the positive and negative terminals of a cylindrical battery are located on opposite sides, electrical connection components such as bus bars for electrically connecting multiple cylindrical batteries must be applied to both the upper and lower parts of the cylindrical batteries, making the electrical connection structure of the battery pack complicated.

[0006] Furthermore, in such a structure, components for insulation and components for ensuring waterproofing must be applied separately to the upper and lower parts of the battery pack, resulting in an increase in the number of components to be applied and a complicated structure.

[0007] Therefore, there is a need to develop a cylindrical battery having a structure in which positive and negative terminals are applied in the same direction so that the electrical connection structure of multiple cylindrical batteries can be simplified. Furthermore, in a cylindrical battery having such a structure, many components for forming the positive and negative terminals are concentrated on one side where the positive and negative terminals are formed. Therefore, a structure for venting due to increased internal pressure and a structure for cutting off current when an overcurrent occurs need to be provided on the opposite side of the direction where the positive and negative terminals are formed. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to enable a cap covering the open portion of a battery housing to simultaneously function as a venting device and a CID (Current Interrupt Device).

[0009] Another object of the present invention is to simplify the electrical connection structure of a plurality of batteries.

[0010] Another object of the present invention is to ensure a sufficient contact area between the battery and an electrical connection component when electrically connecting a plurality of batteries.

[0011] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0012] To solve the above-mentioned problems, one aspect of the present invention provides a battery comprising an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed therebetween around a winding shaft, the first electrode and the second electrode each including a first uncoated portion and a second uncoated portion that are not coated with an active material layer along the winding direction, a battery housing that accommodates the electrode assembly through an opening formed on one side, a cap that has a vent that is thinner than the surrounding area, covers the opening, and is electrically connected to the battery housing and the first uncoated portion, and a battery terminal that is electrically connected to the second uncoated portion.

[0013] The battery housing may be electrically connected to the first uncoated portion through the cap.

[0014] The cap may include a connection portion for electrical connection with the first uncoated portion.

[0015] The venting portion may be formed continuously while describing a closed loop, and the connection portion may be located within the closed loop.

[0016] The venting portion may have a groove shape formed on at least one of an outer surface and an inner surface of the cap.

[0017] The battery terminal may be exposed to the outside of the battery housing by passing through a closed portion of the battery housing located opposite the open portion.

[0018] The battery terminal may extend through a center of the closure.

[0019] The battery terminals may be electrically isolated from the battery housing.

[0020] The battery may further include a first current collector coupled to the first uncoated portion.

[0021] The first current collector may be electrically connected to the cap.

[0022] The first current collector and the cap may be electrically connected via a lead tab.

[0023] The lead tab may have a length greater than the distance between the first current collector and the cap.

[0024] The battery may further include a second current collector coupled to the second uncoated portion.

[0025] The second current collector may be coupled to the battery terminal.

[0026] The battery may further include a sealing gasket interposed between the cap and the battery housing.

[0027] The battery housing may include a beading portion formed by pressing around the outer periphery, and a crimping portion whose end defining the opening below the beading portion is extended and bent to wrap around the periphery of the cap.

[0028] The sealing gasket may be interposed in the remaining area of ​​the crimped portion except for the area where the cap and the battery housing contact each other.

[0029] The battery housing may include a beading portion formed by pressing around the outer periphery, and a crimping portion whose end defining the opening below the beading portion is extended and bent to wrap around the periphery of the cap.

[0030] The periphery of the first current collector may be supported by the beading portion.

[0031] An insulating layer may be interposed between the opposing periphery of the first current collector and the beading portion of the battery housing.

[0032] The insulating layer may be an insulating coating layer formed on one of the first current collector and the beading portion.

[0033] The battery may further include an insulator covering a lower surface of the electrode assembly facing the cap.

[0034] The insulator may have a hole formed at a position corresponding to a hole formed at the winding center of the electrode assembly.

[0035] The first current collector and the cap may be electrically connected via a lead tab, and the insulator may include a hole through which the lead tab passes.

[0036] At least a portion of the first uncoated portion may include a plurality of segments divided along the winding direction of the electrode assembly, and the plurality of segments may be folded along the radial direction of the electrode assembly.

[0037] The folded segments may overlap each other in multiple radial directions.

[0038] The electrode assembly may include a welding target area, which is an area where the overlapping number of the segments of the first uncoated portion is maintained constant along the radial direction of the electrode assembly, and the first current collector may be joined to the first uncoated portion at the welding target area.

[0039] At least a portion of the second uncoated portion may include a plurality of segments divided along the winding direction of the electrode assembly, and the plurality of segments may be folded along the radial direction of the electrode assembly.

[0040] The folded segments may overlap each other in multiple layers along the radial direction.

[0041] The electrode assembly may include a welding target area, which is an area where the overlapping number of the segments of the second uncoated portion is maintained constant along the radial direction of the electrode assembly, and the second current collector may be joined to the second uncoated portion at the welding target area.

[0042] The resistance measured between the positive and negative electrodes may be 4 mΩ or less.

[0043] The battery may have a form factor ratio of diameter divided by height greater than 0.4.

[0044] In order to achieve the above object, a battery pack according to another embodiment of the present invention includes a plurality of the above-described batteries of the present invention.

[0045] The plurality of batteries may be arranged in a predetermined number of rows, with the battery terminals of each battery and the outer surface of the closure of the battery housing facing upward.

[0046] The battery pack may include a plurality of bus bars connecting the plurality of batteries in series and parallel, and the plurality of bus bars may be disposed on top of the plurality of batteries, wherein each of the plurality of bus bars may include a body portion extending between battery terminals of adjacent batteries, a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to the battery terminals of the battery located on that side, and a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to an outer surface of a closing portion of a battery housing of the battery located on the other side.

[0047] In order to solve the above-mentioned problems, a vehicle according to yet another aspect of the present invention includes the above-mentioned battery pack of the present invention. [Effects of the Invention]

[0048] According to one aspect of the present invention, the cap covering the open portion of the battery housing can simultaneously function as a venting device and a CID.

[0049] Furthermore, according to one aspect of the present invention, the electrical connection structure can be simplified since the electrical connection of the plurality of batteries is performed on one side of the batteries in the longitudinal direction.

[0050] Furthermore, according to one aspect of the present invention, a sufficient bonding area between the battery and the component for electrical connection is ensured, thereby reducing electrical resistance and ensuring sufficient bonding strength.

[0051] However, the effects achieved by the present invention are not limited to those described above, and other effects will be clearly understood by those skilled in the art from the description of the invention below.

[0052] 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 concepts of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in the drawings. [Brief explanation of the drawings]

[0053] [Figure 1] 1 is a diagram showing the appearance of a cylindrical battery according to an embodiment of the present invention; [Figure 2] 1 is a cross-sectional view showing the internal structure of a cylindrical battery according to an embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing the lower structure of a battery, illustrating a problem that may occur when the first current collector and the battery housing come into contact with each other in the battery of the present invention. [Figure 3a] 1 is a partial cross-sectional view showing a lower structure of a cylindrical battery according to an embodiment of the present invention; [Figure 3b] 1 is a partial cross-sectional view showing a lower structure of a cylindrical battery according to an embodiment of the present invention; [Figure 4] 1 is a bottom view of a cylindrical battery according to an embodiment of the present invention; [Figure 5] 10 is a conceptual diagram for explaining the positional relationship between a connection portion and a venting portion provided on a cap of the present invention, and the shape of the venting portion. FIG. [Figure 6] 1 is a partial cross-sectional view showing an upper structure of a cylindrical battery according to an embodiment of the present invention; [Figure 7] 10 is a diagram showing an electrode assembly in which a segment is formed. FIG. [Figure 8] 1 is a view showing a bonding structure between a current collector and an uncoated portion of an electrode assembly according to the present invention; [Figure 9] 1 is a view showing a bonding structure between a current collector and an uncoated portion of an electrode assembly according to the present invention; [Figure 10] 1 is a top view illustrating a state in which a plurality of cylindrical batteries are connected in series and parallel using bus bars according to an embodiment of the present invention. FIG. [Figure 11] 1 is a schematic diagram illustrating a battery pack according to an embodiment of the present invention. [Figure 12] 1 is a conceptual diagram showing a vehicle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0054] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0055] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0056] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0057] The expression that two comparison objects are identical means that they are "substantially identical." Therefore, "substantially identical" may include deviations that are considered low in the art, for example, deviations within 5%. Furthermore, the expression that a parameter is uniform in a given region means that the parameter is uniform on average in that region.

[0058] Furthermore, although terms such as "first" and "second" are used to indicate various components, these terms are not intended to limit the components. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component can also be the second component.

[0059] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0060] When an arbitrary structure is placed "on (or under)" a component or "above (or below)" a component, it means not only that the arbitrary structure is placed in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure placed above (or below) the component.

[0061] Furthermore, when a component is said to be "coupled," "coupled," or "connected" to another component, it does not only mean that the components are directly coupled or connected to each other, but also that other components are "intervening" between the components, or that each component is "coupled," "coupled," or "connected" through other components.

[0062] Throughout the specification, unless otherwise specified, "A and / or B" means A, B, or A and B, and "C to D" means C or more and D or less, unless otherwise specified.

[0063] 1 to 3b and 6, a battery 1 according to an embodiment of the present invention may be, for example, a cylindrical battery. The cylindrical battery 1 includes an electrode assembly 10, a battery housing 20, a cap 30, and a battery terminal 40. In addition to the above-mentioned components, the cylindrical battery 1 may further include a first current collector 50 and / or a sealing gasket 60 and / or an insulating gasket 70 and / or a second current collector 80 and / or an insulator (first insulator) 90. The present invention is not limited by the shape of the battery and may also be applied to batteries of other shapes, such as prismatic batteries.

[0064] The electrode assembly 10 includes a first uncoated region 11 and a second uncoated region 12. The electrode assembly 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. The first electrode is a negative or positive electrode, and the second electrode has the opposite polarity to the first electrode.

[0065] The electrode assembly 10 may have, for example, a jelly-roll structure. That is, the electrode assembly 10 may be manufactured by sequentially stacking a first electrode, a separator, and a second electrode at least once and winding the stack. Such a jelly-roll type electrode assembly 10 may have a winding center hole formed at a winding center C and extending along the height direction (Z-axis direction). Meanwhile, a separator may be further provided on the outer periphery of the electrode assembly 10 to insulate it from the battery housing 20.

[0066] The first electrode includes a first conductive substrate and a first electrode active material layer formed by coating one or both surfaces of the first conductive substrate. A first uncoated portion, where the first electrode active material is not coated, is present at one end of the first conductive substrate in the width direction (Z-axis direction). The first uncoated portion extends from one end to the other end along the length of the first electrode when the first electrode is unfolded. The first uncoated portion 11 may function as a first electrode tab. The first uncoated portion 11 is provided on one surface of the electrode assembly 10. More specifically, the first uncoated portion 11 is provided at the lower side in the height direction (Z-axis direction) of the electrode assembly 10 housed in the battery housing 20.

[0067] The second electrode includes a second conductive substrate and a second electrode active material layer formed by coating one or both surfaces of the second conductive substrate. An uncoated portion, where the second electrode active material is not coated, exists at the other end of the second conductive substrate in the width direction (Z-axis direction). The second uncoated portion extends from one end to the other end along the length of the second electrode when the second electrode is unfolded. The second uncoated portion 12 may function as a second electrode tab. The second uncoated portion 12 is provided on the other surface of the electrode assembly 10. More specifically, the second uncoated portion 12 is provided at the upper side in the height direction (Z-axis direction) of the electrode assembly 10 housed in the battery housing 20.

[0068] That is, the first uncoated portion 11 and the second uncoated portion 12 extend and protrude in opposite directions along the height direction (Z-axis direction) of the electrode assembly 10, i.e., the height direction of the cylindrical battery 1, and are exposed to the outside of the separator.

[0069] 7, at least a portion of the first uncoated region 11 and / or the second uncoated region 12 may include a plurality of segments F separated along the winding direction of the electrode assembly 10. In this case, the plurality of segments may be folded along the radial direction of the electrode assembly 10. The folded plurality of segments may overlap in multiple layers. In this case, the first current collector 50 and / or the second current collector 80, which will be described later, may be bonded to the region where the plurality of segments F overlap in multiple layers.

[0070] Meanwhile, the electrode assembly 10 may include a welding target region, which is a region where the number of overlapping layers of the divided segments F of the first uncoated region 11 and / or the second uncoated region 12 is maintained constant along the radial direction of the electrode assembly 10. Because the number of overlapping layers of the divided segments F is maintained at a substantially maximum in the welding target region, it is advantageous to perform welding between the first current collector 50 and the first uncoated region 11 and / or welding between the second current collector 80 and the second uncoated region 12, as described below, in the welding target region. This is to prevent the laser beam from penetrating the first uncoated region 11 and / or the second uncoated region 12 and damaging the electrode assembly 10 when increasing the laser output to improve welding quality, for example, when applying laser welding. This is also to effectively prevent foreign matter, such as welding spatter, from entering the electrode assembly 10.

[0071] 1 to 3b, the battery housing 20 is a generally cylindrical container having an opening at the bottom and is made of a conductive metal material. The side and top of the battery housing 20 may be integrally formed. The top of the battery housing 20, i.e., the outer surface of the closed portion of the battery housing 20, has a generally flat shape. The battery housing 20 accommodates the electrode assembly 10 through an opening formed on one side in the height direction (Z-axis direction) of the battery housing 20, and also accommodates the electrolyte.

[0072] The battery housing 20 may have an open lower end in its height direction (Z-axis direction) and a closed upper end. The battery housing 20 may include a beading portion 21 and a crimping portion 22 formed at its lower end. The beading portion 21 is formed at the bottom of the electrode assembly 10. The beading portion 21 may be formed by pressing around the outer periphery of the battery housing 20. The beading portion 21 prevents the electrode assembly 10, which has a size corresponding to the width (diameter) of the battery housing 20, from slipping out of the opening formed at the lower end of the battery housing 20, and may function as a support on which the cap 30 is placed. Furthermore, the beading portion 21 may also function as a support on which the first current collector 50 is placed. That is, the periphery of the first current collector 50 may be supported by the beading portion 21.

[0073] The crimping portion 22 is formed below the beading portion 21. The crimping portion 22 may have an end that defines the opening of the battery housing 20 below the beading portion 21 and is extended and bent to wrap around the periphery of the cap 30.

[0074] However, the battery housing 20 of the present invention may not have the beading portion 21 and / or the crimping portion 22. In this case, the fixing of the electrode assembly 10 and / or the fixing of the cap 30 and / or the sealing of the battery housing 20 may be achieved, for example, by adding a component that can function as a stopper for the electrode assembly 10 and / or adding a structure on which the cap 30 can be placed and / or by welding between the battery housing 20 and the cap 30.

[0075] Meanwhile, the battery housing 20 has the same polarity as the downwardly extending first uncoated portion 11. The battery housing 20 is electrically connected to the first uncoated portion 11 through a cap 30. The polarity of the battery housing 20 will be described in detail later together with the description of the cap 30.

[0076] 2 to 5, the cap 30 covers an opening formed at the bottom of the battery housing 20 and is electrically connected to the battery housing 20 and the first uncoated portion 11. The cap 30 is a component made of a conductive metal material. The cap 30 includes a venting portion 31 that breaks to release internal gas when internal pressure increases, and a connection portion P for electrical connection with the first uncoated portion 11. In the cylindrical battery 1 of the present invention, the cap 30 functions as a venting member when internal pressure increases due to a battery abnormality, and as a current interrupting member when an overcurrent occurs.

[0077] The cap 30 may be welded to an opening formed at the bottom of the battery housing 20. Alternatively, the cap 30 may be secured within the crimping portion 22 of the battery housing 20 by a sealing gasket 60, which will be described later. Of course, even when the sealing gasket 60 is used, welding may be used for securing the cap 30 to achieve a higher securing force and reduced electrical resistance.

[0078] The cap 30 is electrically connected to the first uncoated portion 11 of the electrode assembly 10. The first uncoated portion 11 of the electrode assembly 10 may be directly coupled to the connection portion P of the cap 30. Alternatively, the first uncoated portion 11 of the electrode assembly 10 may be coupled to the connection portion P of the cap 30 via a first current collector 50 and / or a lead tab L, which will be described later.

[0079] The venting portion 31 corresponds to a region of the cap 30 that is weaker in terms of rigidity than the surrounding region. When the venting portion 31 is formed by adjusting the thickness of the cap 30, the venting portion 31 corresponds to a region of the cap 30 that is thinner than the surrounding region. For example, the venting portion 31 may have a groove shape formed on the outer surface and / or inner surface of the cap 30. When the cap 30 is made of the same material overall and a specific region is formed thinner, if the internal pressure of the battery housing 20 increases abnormally, the thinner region may rupture, allowing gas generated inside to escape from that portion. Alternatively, the venting portion 31 may be formed using a material that is weaker in strength and / or melting point than the surrounding region.

[0080] As will be described later, the cylindrical battery 1 according to one embodiment of the present invention has a structure in which battery terminals 40 are provided at the upper part in the height direction (Z-axis direction), making the structure of the upper part more complex than that of the lower part. Therefore, a venting portion 31 may be formed in the cap 30 forming the bottom surface of the cylindrical battery 1 to allow internal gas to be discharged through venting.

[0081] Meanwhile, the venting portion 31 is continuously formed to form a closed loop, and the connection portion P is located within this closed loop. That is, current moving from the first uncoated portion 11 of the electrode assembly 10 through the cap 30 to the battery housing 20 necessarily passes through the venting portion 31. This is because the cap 30 functions as a current interrupting device when an overcurrent occurs, in addition to its function as a venting device. If the connection portion P is located outside the closed loop of the venting portion 31, the current path will not pass through the venting portion 31, and the venting portion 31 will not function as a current interrupting device. Also, even if the connection portion P is located within the roof formed by the venting portion 31, if the roof is partially open rather than forming a closed loop, as shown in FIG. 5, the current transferred from the electrode assembly 10 to the cap 30 will flow through the open area, and in this case too, the venting portion 31 will not function as a current interrupting device.

[0082] 1, 2, and 6, the battery terminal 40 may pass through a closed portion located opposite an open portion formed on one side of the battery housing 20. The battery terminal 40 is electrically connected to the second uncoated portion 12 of the electrode assembly 10 within the battery housing 20. The battery terminal 40 may be directly coupled to the second uncoated portion 12, or may be electrically connected to the electrode assembly 10 through a second current collector 80, which will be described later. The battery terminal 40 is a component made of a conductive metal material. The battery terminal 40 is electrically insulated from the battery housing 20.

[0083] Insulation between the battery terminal 40 and the battery housing 20 can be achieved in various ways. For example, insulation can be achieved by applying an insulating gasket 70. As another example, insulation can be achieved by applying an insulating coating to at least a portion of the battery terminal 40 and / or the battery housing 20. As yet another example, insulation can be achieved by firmly fixing the battery terminal 40 so that the battery terminal 40 and the battery housing 20 are kept separated from each other, without applying a treatment such as an insulating coating or a separate component.

[0084] The battery terminal 40 may penetrate approximately the center of the upper surface (a surface parallel to the XY plane) of the battery housing 20. At least a portion of the battery terminal 40 inserted into the battery housing 20 may be coupled to the second uncoated portion 12 or the second current collector 80 of the electrode assembly 10 by welding, etc. Also, at least a portion of the battery terminal 40 inserted into the battery housing 20 may be bent toward the upper surface of the battery housing 20 and riveted. That is, the battery terminal 40 of the present invention may be a rivet-type terminal that penetrates the battery housing 20 and is coupled to the inner surface of the battery housing 20 by riveting.

[0085] In this way, in the cylindrical battery 1 of the present invention, the top surface of the battery housing 20, i.e., the outer surface of the closed portion, which has the same polarity as the first uncoated portion 11, can function as the first electrode terminal T1, and the battery terminal 40, which has the same polarity as the second uncoated portion 12, can function as the second electrode terminal T2. Therefore, the cylindrical battery 1 of the present invention has a structure in which a pair of electrode terminals (first electrode terminal T1, second electrode terminal T2) are all provided on one side in the height direction, and therefore, when electrically connecting multiple cylindrical batteries 1, all electrical connection parts are concentrated in one direction. This structure simplifies the structure during battery pack manufacturing, thereby improving productivity and energy density.

[0086] Furthermore, in the cylindrical battery 1 of the present invention, the entire area of ​​the substantially flat top surface of the battery housing 20, excluding the area occupied by the battery terminal 40, can be used as the first electrode terminal T1. Therefore, a sufficient bonding area can be secured when connecting an electrical connection component such as a bus bar to the first electrode terminal T1, which allows for easy connection even when a large-area bus bar is used, and reduces electrical resistance at the connection site.

[0087] 2 to 3b, the first current collector 50 may be coupled to a lower end of the electrode assembly 10 in the height direction (Z-axis direction). The first current collector 50 may be coupled to a first uncoated portion 11. The first current collector 50 is electrically connected to the cap 30. That is, when the cylindrical battery 1 includes the first current collector 50, the first uncoated portion 11 of the electrode assembly 10 is electrically connected to the cap 30 through the first current collector 50. The first current collector 50 may be electrically connected to the cap 30, for example, through a lead tab L. The lead tab L may be a component integrally formed with the first current collector 50, or may be provided separately, with one side coupled to the first current collector 50 and the other side coupled to the cap 30. Referring to FIG. 5 in addition to FIGS. 2 and 3, the first current collector 50 or the lead tab L is coupled to a connection portion P of the cap 30, and the connection portion P is located within a closed loop formed by the venting portion 31. This is to ensure that the current passing between the first current collector 50 and the battery housing 20 always passes through the venting portion 31, thereby enabling the venting portion 31 to quickly cut off the overcurrent when it occurs.

[0088] Preferably, the length of the lead tab L may be configured to be longer than the distance between the first current collector 50 and the cap 30. This is to prevent the breakage pressure of the venting portion 31 from becoming larger than the designed value due to the lead tab L if the extension length of the lead tab L is insufficient.

[0089] Meanwhile, the first current collector 50 may have a current collector hole 50a formed at a position corresponding to a hole formed at the winding center C of the electrode assembly 10. The current collector hole 50a is connected to the hole formed at the winding center C of the electrode assembly 10, so that the second current collector 80 located on the opposite side of the first current collector 50 can be welded to the battery terminal 40 by inserting a tool or irradiating a laser beam through the winding center hole of the electrode assembly 10. The current collector hole 50a may also function as a passage for injecting an electrolyte.

[0090] 2 to 3b, the sealing gasket 60 is a component applied to improve the sealing performance of the cap 30 covering the lower open end of the battery housing 20 in the height direction (Z-axis direction). Considering this function, the sealing gasket 60 may be made of an elastic material. The sealing gasket 60 is partially interposed between the battery housing 20 and the cap 30. As described above, the battery housing 20 must be in contact with the cap 30 to establish an electrical connection. Therefore, the sealing gasket 60 must not completely block contact between the battery housing 20 and the cap 30. To this end, the sealing gasket 60 is interposed between the cap 30 and the battery housing 20 in the area where the crimping portion 22 of the battery housing 20 is formed, but may also be interposed in areas other than the area where the cap 30 and the battery housing 20 contact each other.

[0091] 1, 2, and 6, the insulating gasket 70 is interposed between the battery housing 20 and the battery terminal 40 to prevent contact between the battery housing 20 and the battery terminal 40, which have opposite polarities. Furthermore, the insulating gasket 70 prevents a decrease in the sealing performance of the battery housing 20 due to the application of the battery terminal 40. In consideration of this function, a material having insulating and elastic properties may be used as the material for the insulating gasket 70. A portion of the insulating gasket 70 may bend toward the inner surface of the closed portion of the battery housing 20 together with the flange portion of the battery terminal 40 when the battery terminal 40 is riveted. Thus, a portion of the insulating gasket 70 may be interposed between the flange portion of the battery terminal 40 and the inner surface of the closed portion of the battery housing 20.

[0092] 6, the second current collector 80 is coupled to the upper end of the electrode assembly 10 in the height direction (Z-axis direction). Accordingly, the second current collector 80 is coupled to the second uncoated portion 12. The second current collector 80 is electrically connected to the battery terminal 40. That is, when the cylindrical battery 1 includes the second current collector 80, the second uncoated portion 12 of the electrode assembly 10 is electrically connected to the battery terminal 40 through the second current collector 80. The second current collector 80 may be directly coupled to the battery terminal 40. Alternatively, the second current collector 80 may be electrically connected to the battery terminal 40 through a separate component such as a lead tab (not shown), similar to the first current collector 50 (see FIG. 3). In this case, the lead tab may be a component integrally formed with the second current collector 80, or may be provided separately from the second current collector 80, with one side coupled to the second current collector 80 and the other side coupled to the battery terminal 40.

[0093] Meanwhile, referring to FIGS. 8 and 9, a coupling structure between the current collectors (first current collector 50, second current collector 80) and the electrode assembly 10 applied to the present invention is shown.

[0094] 8 , the second current collector 80 may be bonded to a bonding surface formed by bending an end of the second uncoated portion 12 in a direction substantially parallel to the second current collector 80. The bonding between the second uncoated portion 12 and the second current collector 80 may be performed, for example, by laser welding. The laser welding may be performed by partially melting the base material of the second current collector 80, and may be performed with solder interposed between the second current collector 80 and the second uncoated portion 12. In this case, it is preferable that the solder has a lower melting point than the second current collector 80 and the second uncoated portion 12.

[0095] 9, the first current collector 50 may be bonded to a bonding surface formed by bending an end of the first uncoated portion 11 in a direction parallel to the first current collector 50. The bending direction of the first uncoated portion 11 may be, for example, a direction toward the winding center C of the electrode assembly 10.

[0096] When the first uncoated portion 11 and / or the second uncoated portion 12 have such a folded shape, the space occupied by the first uncoated portion 11 and / or the second uncoated portion 12 in the height direction (Z-axis direction) of the electrode assembly 10 is reduced, i.e., the height (length in the Z-axis direction) of the electrode assembly 10 is reduced, resulting in an improvement in energy density.

[0097] 6, the insulator 90 is interposed between the upper end of the electrode assembly 10 and the inner surface of the battery housing 20, or between the second current collector 80 coupled to the upper part of the electrode assembly 10 and the inner surface of the battery housing 20. The insulator 90 may have an extended shape so as to further cover the side surface of the electrode assembly 10. The insulator 90 prevents contact between the second uncoated portion 12 and the battery housing 20 or between the second current collector 80 and the battery housing 20.

[0098] When the cylindrical battery 1 of the present invention includes an insulator 90 disposed on the upper portion of the electrode assembly 10, the battery terminal 40 penetrates the insulator 90 inside the battery housing 20 and is coupled to the second current collector 80 or the second uncoated portion 12.

[0099] 3, if the first current collector 50 and the battery housing 20 are in direct contact, the cap 30 of the present invention cannot function as an overcurrent interrupting member. In order for the cap 30 to function as an overcurrent interrupting member, electrical connection between the first current collector 50 and the battery housing 20 must be established through the cap 30. This is because if the current transmitted from the first current collector 50 does not pass through the venting portion 31 formed in the cap 30, the venting portion 31, which is thinner than the surrounding area, will break due to the overcurrent and will not be able to interrupt the overcurrent.

[0100] Referring to FIGS. 3a and 3b, in order to prevent direct contact between the first current collector 50 and the battery housing 20, an insulating layer CL and / or an insulator (second insulator) IS may be interposed between the first current collector 50 and the battery housing 20.

[0101] The insulating layer CL may be interposed between the peripheral edge of the first current collector 50 and the beading portion 21 of the battery housing 20. The insulating layer CL may be, for example, an insulating coating layer formed on the surface of either the first current collector 50 and / or the beading portion 21.

[0102] The insulator (second insulator) IS may cover the lower surface of the electrode assembly 10 facing the cap 30. The insulator IS may have an extended shape so as to be interposed between the opposing first uncoated portion 11 and the inner surface of the side wall of the battery housing 20. The insulator IS may have a hole formed at a position corresponding to the hole formed in the winding center C of the electrode assembly 10. This hole may function as a passage for injecting an electrolyte and / or a passage for inserting a tool or passing a laser beam for welding the second current collector 80 and the battery terminal 40. Meanwhile, the insulator IS may have a hole through which a lead tab L passes, electrically connecting the first current collector 50 and the cap 30.

[0103] The cylindrical battery 1 of the present invention described above has a structure in which resistance is minimized by enlarging the welding area by forming a joining surface by bending the uncoated portions (first uncoated portion 11, second uncoated portion 12) and by joining the bus bar using the outer surface of the closed portion of the battery housing 20. The AC resistance of the cylindrical battery 1 measured with a resistance meter between the positive and negative electrodes, and between the battery terminal 40 (second electrode terminal T2) and its surrounding approximately flat surface (first electrode terminal T1), may be approximately 0.5 mΩ to 4 mΩ, and preferably approximately 1 mΩ to 4 mΩ, which is suitable for fast charging.

[0104] Desirably, the cylindrical battery may be, for example, a cylindrical battery having a form factor ratio (defined as the diameter of a cylindrical battery divided by its height, i.e., the ratio of height (H) to diameter (Φ)) greater than about 0.4.

[0105] Here, form factor refers to values ​​indicating the diameter and height of a cylindrical battery. Desirably, the diameter of a cylindrical battery may be approximately 40 mm to 50 mm, and the height may be approximately 60 mm to 130 mm. Cylindrical batteries according to one embodiment of the present invention may be, for example, 46110 batteries, 4875 batteries, 48110 batteries, 4880 batteries, or 4680 batteries. In the numerical value indicating the form factor, the first two digits indicate the diameter of the battery, and the remaining digits indicate the height of the battery.

[0106] When a tab-less electrode assembly is applied to a cylindrical battery with a form factor ratio exceeding 0.4, the uncoated portion is susceptible to tearing due to the large radial stress applied when the uncoated portion is bent. Furthermore, when welding a current collector to the bent surface area of ​​the uncoated portion, the number of uncoated portions stacked on the bent surface area must be increased to ensure sufficient weld strength and reduce resistance. These requirements can be met by the electrode and electrode assembly according to an embodiment (variant) of the present invention.

[0107] A battery according to one embodiment of the present invention may be a generally cylindrical battery having a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of about 0.418.

[0108] Another embodiment of the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of about 0.640.

[0109] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of about 0.418.

[0110] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of about 0.600.

[0111] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of about 0.575.

[0112] Conventionally, batteries with a form factor ratio of approximately 0.4 or less have been used. For example, 1865 batteries and 2170 batteries have been used. 1865 batteries have a diameter of approximately 18 mm and a height of approximately 65 mm, resulting in a form factor ratio of approximately 0.277. 2170 batteries have a diameter of approximately 21 mm and a height of approximately 70 mm, resulting in a form factor ratio of approximately 0.300.

[0113] 10, a plurality of cylindrical batteries 1 may be connected in series and parallel at the top of the cylindrical batteries 1 using bus bars 150. The number of cylindrical batteries 1 may be increased or decreased depending on the capacity of the battery pack.

[0114] In each cylindrical battery 1, the battery terminal 40 (second electrode terminal T2) may have a positive polarity, and the outer surface of the closed part of the battery housing 20 (first electrode terminal T1) may have a negative polarity. Of course, the opposite is also possible.

[0115] Preferably, a plurality of cylindrical batteries 1 may be arranged in a plurality of rows and columns. The columns are arranged vertically relative to the ground, and the rows are arranged horizontally relative to the ground. To maximize space efficiency, the cylindrical batteries 1 may be arranged in the closest packing structure. This closest packing structure is formed when an equilateral triangle is drawn when the centers of the battery terminals 40 exposed to the outside of the battery housing 20 are connected to each other. Preferably, the bus bar 150 may be arranged on top of the plurality of cylindrical batteries 1, more preferably between adjacent columns. Alternatively, the bus bar 150 may be arranged between adjacent rows.

[0116] Preferably, the bus bars 150 connect the batteries 1 arranged in the same row in parallel to each other, and connect the cylindrical batteries 1 arranged in two adjacent rows in series to each other.

[0117] Preferably, the bus bar 150 may include a body portion 151, a plurality of first bus bar terminals 152, and a plurality of second bus bar terminals 153 for series and parallel connection.

[0118] The body portion 151 may extend between the battery terminals 40 of adjacent cylindrical batteries 1, preferably between rows of cylindrical batteries 1. Alternatively, the body portion 151 may extend along the row of cylindrical batteries 1, but may also be bent regularly, such as in a zigzag pattern.

[0119] The plurality of first bus bar terminals 152 may protrude from one side of the body portion 151 toward the battery terminals 40 of each cylindrical battery 1 and be electrically coupled to the battery terminals 40. The electrical coupling between the first bus bar terminals 152 and the battery terminals 40 may be performed by laser welding, ultrasonic welding, etc. The plurality of second bus bar terminals 153 may be electrically coupled from the other side of the body portion 151 to the outer surface T1 of the closed portion of the battery housing 20 of each cylindrical battery 1. The electrical coupling between the second bus bar terminals 153 and the outer surface T1 may be performed by laser welding, ultrasonic welding, etc.

[0120] Preferably, the body portion 151, the plurality of first bus bar terminals 152, and the plurality of second bus bar terminals 153 may be formed from a single conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present invention is not limited thereto. Alternatively, the body portion 151, the plurality of first bus bar terminals 152, and the second bus bar terminals 153 may be manufactured as separate pieces and then joined together by welding or the like.

[0121] In the cylindrical battery 1 according to the present invention, the battery terminal 40 having a positive polarity and the outer surface T1 of the closed portion of the battery housing 20 having a negative polarity are positioned in the same direction, so electrical connection between cylindrical batteries 1 can be easily achieved using the bus bar 150.

[0122] In addition, since the battery terminals 40 of the cylindrical battery 1 and the outer surface T1 of the closed portion of the battery housing 20 have a large area, the connection area of ​​the bus bar 150 can be sufficiently secured, thereby sufficiently reducing the resistance of the battery pack including the cylindrical battery 1.

[0123] 11, a battery pack 3 according to an embodiment of the present invention includes a battery assembly in which a plurality of cylindrical batteries 1 according to an embodiment of the present invention are electrically connected, and a pack housing 2 that accommodates the battery assembly. The electrical connection structure of the plurality of batteries 1 through bus bars is as exemplarily described above with reference to FIG. 10, and other components such as a cooling unit and power terminals are omitted for convenience of illustration.

[0124] 12, an automobile 5 according to an embodiment of the present invention may be, for example, an electric automobile, and includes a battery pack 3 according to an embodiment of the present invention. The automobile 5 operates by receiving a supply of power from the battery pack 3 according to an embodiment of the present invention.

[0125] As described above, the present invention has been described using limited embodiments and drawings, but 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 pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0126] 5: Automobiles 3: Battery pack 2: Pack housing 1: Battery 10: Electrode assembly C: Winding center 11: First plain area 12: Second plain area F: Minute section 20: Battery housing T1: 1st electrode terminal 21: Beading section 22: Crimping section 30: Cap 31: Venting section 40:Battery terminal T2: 2nd electrode terminal 50: First current collector L: Lead tab 60: Sealing gasket 70: Insulation gasket 80: Second current collector 90: Insulator (first insulator) IS: Insulator (second insulator) CL: Insulating layer

Claims

1. an electrode assembly in which a first electrode, a second electrode and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode and the second electrode each including a first uncoated portion and a second uncoated portion that are not coated with an active material layer along a winding direction; a battery housing that receives the electrode assembly through an opening formed on one side thereof; a cap including a vent portion that is thinner than a surrounding area, the cap covering the opening and electrically connected to the battery housing and the first plain portion; a battery terminal electrically connected to the second uncoated portion; Including, the battery housing is electrically connected to the first uncoated portion through the cap, The battery, wherein the battery terminal penetrates a closed portion of the battery housing opposite the open portion and is exposed to the outside of the battery housing.

2. The battery of claim 1 , wherein the cap includes a connection portion for electrical connection with the first solid portion.

3. The venting portion is formed continuously while describing a closed loop, The battery of claim 2 , wherein the connection is located within the closed loop.

4. The battery according to claim 1 , wherein the venting portion has a groove shape formed on at least one of an outer surface and an inner surface of the cap.

5. 5. The battery of claim 1, wherein the battery terminal passes through a center of the closure.

6. 6. The battery of claim 1, wherein the outer surface of the closure is flattened.

7. 7. The battery of claim 1, wherein the battery terminals are electrically insulated from the battery housing.

8. The battery of claim 1 , further comprising a first current collector coupled to the first non-coating portion.

9. 9. The battery of claim 8, wherein the first current collector is electrically connected to the cap.

10. 10. The battery of claim 9, wherein the first current collector and the cap are electrically connected via a lead tab.

11. 11. The battery of claim 10, wherein the lead tab has a length greater than a distance between the first current collector and the cap.

12. The battery of claim 1 , further comprising a second current collector coupled to the second non-coating portion.

13. 13. The battery of claim 12, wherein the second current collector is coupled to the battery terminal.

14. 14. The battery of claim 1, further comprising a sealing gasket interposed between the cap and the cell housing.

15. The battery housing comprises: A beading portion formed by pressing in the periphery of the outer circumferential surface; a crimping portion, the end of which defines the opening below the beading portion and is extended and bent to wrap around the periphery of the cap; 15. The battery of claim 14, comprising:

16. The battery according to claim 15 , wherein the sealing gasket is interposed in a remaining area except for an area where the cap and the battery housing contact each other in the area where the crimping portion is formed.

17. The battery housing comprises: A beading portion formed by pressing in the periphery of the outer circumferential surface; a crimping portion, the end of which defines the opening below the beading portion and is extended and bent to wrap around the periphery of the cap; Equipped with The battery according to claim 8 , wherein a periphery of the first current collector is supported by the beading portion.

18. 18. The battery of claim 17, wherein an insulating layer is interposed between the facing periphery of the first current collector and the beading portion of the cell housing.

19. The battery of claim 18 , wherein the insulating layer is an insulating coating layer formed on a surface of any one of the first current collector and the beading portion.

20. 20. The battery of claim 17, further comprising an insulator covering a lower surface of the electrode assembly facing the cap.

21. 21. The battery of claim 20, wherein the insulator has a hole formed at a position corresponding to a hole formed in a winding center of the electrode assembly.

22. the first current collector and the cap are electrically connected via a lead tab; 22. The battery of claim 20 or 21, wherein the insulator includes a hole through which the lead tab passes.

23. At least a portion of the first uncoated portion includes a plurality of segments separated along a winding direction of the electrode assembly, The battery according to claim 8 , wherein the plurality of segments are folded along a radial direction of the electrode assembly.

24. The battery of claim 23 , wherein the folded sections overlap each other in multiple radial directions.

25. the electrode assembly includes a welding target area, which is an area where an overlapping number of the plurality of segments of the first uncoated portion is maintained constant along a radial direction of the electrode assembly, 25. The battery of claim 24, wherein the first current collector is joined to the first non-coating portion at the weld target area.

26. At least a portion of the second uncoated portion includes a plurality of segments separated along a winding direction of the electrode assembly, The battery according to claim 12 , wherein the plurality of segments are folded along a radial direction of the electrode assembly.

27. 27. The battery of claim 26, wherein the folded sections overlap each other in multiple layers along the radial direction.

28. the electrode assembly includes a welding target area, which is an area where an overlapping number of the plurality of segments of the second uncoated portion is maintained constant along a radial direction of the electrode assembly, 28. The battery of claim 27, wherein the second current collector is joined to the second non-coated portion at the weld target area.

29. 29. The battery of any one of claims 1 to 28, wherein the form factor ratio of the battery's diameter divided by its height is greater than 0.

4.

30. 30. A battery pack comprising a plurality of batteries according to any one of claims 1 to 29.

31. The plurality of batteries are arranged in a predetermined number of rows; 31. The battery pack of claim 30, wherein an outer surface of the battery terminals and battery housing closure of each of the batteries are disposed toward an upper portion.

32. The battery pack includes a plurality of bus bars connecting the plurality of batteries in series and in parallel, the bus bars are disposed on top of the batteries; Each of the plurality of bus bars is a body portion extending between the battery terminals of adjacent batteries; a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to battery terminals of a battery located at the one side; a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to an outer surface of a closing portion of a battery cell housing of a battery located on the other side; 32. The battery pack of claim 30 or 31, comprising:

33. 33. A motor vehicle comprising a battery pack according to any one of claims 30 to 32.

Images