Current collector plate, cylindrical battery cell including same, and battery pack and vehicle including cylindrical battery cell

Abstract

Disclosed are a current collector plate, a cylindrical battery cell including same, and a battery pack and a vehicle including the cylindrical battery cell. The current collector plate according to an embodiment of the present invention is a current collector plate for electrically connecting an electrode assembly accommodated in the cylindrical battery cell. The current collector plate comprises: an edge part defining the edge thereof; a center part spaced apart from the edge part and coupled to the electrode assembly; and a connection part for connecting the center part to the edge part, wherein the width of the connection part varies.

Description

A current collector and a cylindrical battery cell including the same, and a battery pack and a vehicle including the cylindrical battery cell

[0001] This application claims priority to Korean Patent Application No. 10-2023-0101813, filed on August 3, 2023, and Korean Patent Application No. 10-2024-0037365, filed on March 18, 2024, all of which are incorporated herein by reference in their entirety.

[0002] The present invention relates to a current collector plate and a cylindrical battery cell including the same, and a battery pack and a vehicle including the cylindrical battery cell, and more particularly, to a current collector plate capable of breaking a connection when a short-circuit current is applied without increasing the internal resistance of the battery cell, and a cylindrical battery cell including the same, and a battery pack and a vehicle including the cylindrical battery cell.

[0003] Secondary batteries, which have high applicability according to product group and electrical characteristics such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electrical power sources.

[0004] These secondary batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency because they not only have the primary advantage of drastically reducing the use of fossil fuels, but also have the advantage of producing no byproducts from energy use.

[0005] Commonly used secondary battery types include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells ranges from approximately 2.5 V to 4.5 V.

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

[0007] Meanwhile, known secondary battery cell types include cylindrical, prismatic, and pouch-shaped battery cells. Cylindrical battery cells are constructed by interposing a separator, which serves as an insulator, between the positive and negative plates, winding the separator to form a jelly-roll-shaped electrode assembly. This assembly, along with an electrolyte, is then inserted into a battery can to form the battery. Furthermore, cylindrical battery cells may use current collectors to electrically connect the positive and negative plates.

[0008] Meanwhile, with the recent adoption of cylindrical battery cells in electric vehicles, their form factors are increasing. Specifically, the diameter and height of cylindrical battery cells are increasing compared to conventional cylindrical battery cells with form factors such as 18650 and 21700. This increase in form factor leads to increased energy density, enhanced safety against thermal runaway, and improved cooling efficiency.

[0009] Here, as form factors increase, the need to protect cylindrical battery cells from short-circuit currents and other issues also increases. For example, a fusing element (e.g., a notched groove) can be formed on the current collector plate. However, simply forming a fusing element on the current collector plate does not facilitate smooth disconnection of the current collector plate connection without increasing the internal resistance of the battery cell when a short-circuit current is applied.

[0010] Normally, when the internal resistance of a battery cell increases, the internal resistance impedes the flow of current, so that when a short-circuit current is applied, the connection of the collector plate is not broken, and the current continues to flow, eventually causing the battery cell to catch fire or explode.

[0011] Therefore, there is a need for a structure in which the collector plate is disconnected when a short-circuit current is applied without increasing the internal resistance of the battery cell.

[0012] Accordingly, the technical problem to be solved by the present invention is to provide a current collector plate capable of disconnecting a connection when a short-circuit current is applied without increasing the internal resistance of the battery cell, a cylindrical battery cell including the current collector plate, and a battery pack and a vehicle including the cylindrical battery cell.

[0013] In addition, the present invention provides a current collector plate capable of preventing ignition of a battery cell by blocking the flow of current due to a break in the connection of the current collector plate when a short-circuit current is applied, a cylindrical battery cell including the current collector plate, and a battery pack and a vehicle including the cylindrical battery cell.

[0014] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0015] According to one aspect of the present invention, a current collector plate for electrically connecting an electrode assembly housed inside a cylindrical battery cell may be provided, the current collector plate including a rim portion defining a rim; a center portion spaced from the rim portion and coupled to the electrode assembly; and a connecting portion connecting the rim portion and the center portion, wherein the width of the connecting portion is formed to vary.

[0016] In one embodiment, the border portion may have a rim shape in which at least a portion of the inner area is empty.

[0017] In one embodiment, the connecting portion includes a first portion connected to the central portion and a second portion connected to the edge portion, and the width of the first portion may be narrower than the width of the second portion.

[0018] In one embodiment, the first connecting portion of the first portion and the second portion may be formed to be inclined.

[0019] In one embodiment, the first connecting portion includes a first inclined portion on one side and a second inclined portion on the other side, and the first inclined portion and the second inclined portion may be formed symmetrically to each other.

[0020] In one embodiment, the first connecting portion may be formed to be inclined so as to extend from the first portion toward the second portion and be connected to the second portion.

[0021] In one embodiment, the end of the second portion is located further from the center than the end of the first portion on the outside of the end of the first portion, and the first connecting portion can connect the end of the first portion and the end of the second portion from the end of the first portion toward the second portion.

[0022] In one embodiment, the first connecting portion may be formed to be inclined so as to extend from the first portion toward the center and be connected to the second portion.

[0023] In one embodiment, the end of the second portion is positioned closer to the center than the end of the first portion on the outside of the end of the first portion, and the first connecting portion can connect the end of the second portion from the end of the first portion toward the center.

[0024] In one embodiment, the first portion and the second portion may be connected vertically to each other.

[0025] In one embodiment, the end of the second portion is located outside the end of the first portion, the end of the second portion and the end of the first portion are located at the same distance from the center, and the first connecting portion can connect the end of the first portion and the end of the second portion to each other.

[0026] In one embodiment, the second connecting portion of the second portion and the edge portion may be formed to be inclined.

[0027] In one embodiment, the second connecting portion includes a third inclined portion on one side and a fourth inclined portion on the other side, and the third inclined portion and the fourth inclined portion may be formed symmetrically.

[0028] In one embodiment, a through hole may be formed between the third inclined portion and the fourth inclined portion.

[0029] Meanwhile, according to another aspect of the present invention, a cylindrical battery cell including at least one of the aforementioned current collector plates may be provided, and further, a battery pack including at least one of the aforementioned cylindrical battery cells may be provided, and further, a vehicle including at least one of the aforementioned cylindrical battery cells may be provided.

[0030] According to one aspect of the present invention, there is an effect in which a connection can be broken when a short-circuit current is applied without increasing the internal resistance of the battery cell.

[0031] In addition, when a short-circuit current is applied, the current flow is blocked due to the rupture of the connection part of the current collector plate, which has the effect of preventing the battery cell from igniting.

[0032] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0033] FIG. 1 is a drawing illustrating a current collector plate according to one embodiment of the present invention.

[0034] Figure 2 is an enlarged view of part A of Figure 1.

[0035] FIG. 3 is a drawing showing a current collector plate according to a modified embodiment of FIG. 1.

[0036] Figure 4 is an enlarged view of part B of Figure 3.

[0037] FIG. 5 is a drawing showing a current collector plate according to another modified embodiment of FIG. 1.

[0038] Figure 6 is an enlarged view of part C of Figure 5.

[0039] Figure 7 is a drawing showing the test conditions of the collector plate of Figure 1.

[0040] Figures 8(a) to 8(C) are graphs of test results according to the test conditions of Figure 7.

[0041] FIG. 9 is a diagram showing fusing occurring in a test of a current collector plate according to the embodiment of FIG. 1.

[0042] Figure 10 is a drawing showing a current collector plate according to a comparative example of each embodiment of the present invention.

[0043] Fig. 11 is a drawing showing the test conditions of the collector plate of Fig. 10.

[0044] Figures 12(a) to 12(C) are graphs of test results according to the test conditions of Figure 11.

[0045] FIG. 13 is a schematic cross-sectional view of a cylindrical battery cell including a current collector plate according to each embodiment of the present invention.

[0046] FIG. 14 is a schematic drawing showing the configuration of a battery pack including a cylindrical battery cell according to each embodiment of the present invention.

[0047] FIG. 15 is a drawing for explaining a vehicle including a battery pack according to each embodiment of the present invention.

[0048] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Terms or words used in this specification and claims should not be interpreted as limited to their conventional or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to best explain his or her own invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention, and various equivalents and modifications may exist as of the time of this application.

[0049] In the drawings, the sizes of each component or specific parts of that component are exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect its actual size. If a detailed description of a related known function or configuration is deemed to unnecessarily obscure the gist of the present invention, such description will be omitted.

[0050] The term 'joint' or 'connection' as used herein includes 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 through a connecting member.

[0051] FIG. 1 is a drawing showing a current collector plate according to one embodiment of the present invention, and FIG. 2 is an enlarged view of part A of FIG. 1.

[0052] A current collector plate (10) according to one embodiment of the present invention is configured to electrically connect an electrode assembly (21, see FIG. 13) housed inside a cylindrical battery cell (20, see FIG. 13). A detailed description of the cylindrical battery cell (20) will be described later. A current collector plate (10) according to one embodiment of the present invention can be used in a positive current collector plate (23, see FIG. 13) of a cylindrical battery cell (20).

[0053] Referring to FIG. 1, a current collector plate (10) according to one embodiment of the present invention includes a frame portion (100), a center portion (200), and a connection portion (300). The current collector plate (10) is configured to electrically connect an electrode assembly (21) housed inside a cylindrical battery cell (20).

[0054] The rim portion (100) defines a rim and may have a roughly rim shape in which at least a portion of the inner area is empty to form an inner space. In the case of FIG. 1, the rim portion (100) is illustrated as having a roughly circular rim shape, but the shape of the rim portion (100) is not limited thereto. Unlike what is illustrated, the rim portion (100) may have a roughly square rim shape, a hexagonal rim shape, an octagonal rim shape, or other shapes. The rim portion (100) may be coupled to the connecting portion (300).

[0055] The central portion (200) is located on the inside of the rim portion (100) and is spaced apart from the rim portion (100). For example, the central portion (200) may be located at the exact center of the inner space of the rim portion (100), but is not limited thereto. In addition, the central portion (200) is coupled to the connecting portion (300) and is connected to the rim portion (100) by the connecting portion (300). In addition, the central portion (200) is coupled to the electrode assembly (21) of the cylindrical battery cell (20). However, not only the central portion (200) is coupled to the electrode assembly (21), but the rim portion (100) and the connecting portion (300) may also be coupled to the electrode assembly (21). In addition, the central portion (200) may be positioned at a position corresponding to the central hole of the electrode assembly (21).

[0056] The connecting portion (300) connects the edge portion (100) and the center portion (200). A plurality of connecting portions (300) may be provided, and the plurality of connecting portions (300) may be spaced apart from each other. In Fig. 1, four connecting portions (300) are provided, but the number of connecting portions (300) is not limited thereto. In addition, the plurality of connecting portions (300) may be arranged at equal intervals from each other, but is not limited thereto.

[0057] Referring to FIGS. 1 and 2, the connecting portion (300) can be formed to have a varying width. That is, the connecting portion (300) connects the edge portion (100) and the center portion (200), and the width of the connecting portion (300) changes from the edge portion (100) to the center portion (200), or from the center portion (200) to the edge portion (100).

[0058] The connecting portion (300) may include a first portion (310) connected to the center portion (200) and a second portion (320) connected to the edge portion (100). Referring to FIGS. 1 and 2, the width of the first portion (310) may be narrower than the width of the second portion (320). That is, the width of the connecting portion (300) gradually widens from the relatively narrow first portion (310) toward the second portion (320).

[0059] And, the first connecting portion (330) of the first part (310) and the second part (320) can be formed to be inclined. That is, it is connected to the second part (320) from the first part (310) to be inclined.

[0060] And, referring to FIG. 2, the first connecting portion (330) may include a first inclined portion (331) on one side and a second inclined portion (332) on the other side, and the first inclined portion (331) and the second inclined portion (332) may be configured to have the same inclination in opposite directions. That is, referring to FIG. 2, the first inclined portion (331) may be formed in the X direction, and the second inclined portion (332) may be formed in the Y direction. By this structure, the first inclined portion (331) and the second inclined portion (332) may be formed symmetrically.

[0061] Referring to FIG. 2, the first connecting portion (330) may be formed to be inclined so as to extend from the first portion (310) toward the second portion (320) and may be connected to the second portion (320). For example, the end portion (321) of the second portion (320) is located further from the center (200) than the end portion (311) of the first portion (310) on the outside of the end portion (311) of the first portion (310). In addition, the first connecting portion (330) may be configured to connect the end portion (311) of the first portion (310) and the end portion (321) of the second portion (320) from the end portion (311) of the first portion (310) toward the second portion (320).

[0062] FIG. 3 is a drawing showing a current collector plate according to a modified embodiment of FIG. 1, and FIG. 4 is an enlarged view of part B of FIG. 3.

[0063] Referring to FIGS. 3 and 4, the end (321) of the second portion (320) is positioned outside the end (311) of the first portion (310), the end (321) of the second portion (320) and the end (311) of the first portion (310) are positioned at the same distance from the center (200), and the first connecting portion (330) can be configured to connect the end (311) of the first portion (310) and the end (321) of the second portion (320) to each other. As a result, the first portion (310) and the second portion (320) can be vertically connected to each other.

[0064] FIG. 5 is a drawing showing a current collector plate according to another modified embodiment of FIG. 1, and FIG. 6 is an enlarged view of part C of FIG. 5.

[0065] Referring to FIGS. 5 and 6, the first connecting portion (330) may be formed to be inclined so as to extend from the first portion (310) toward the center (200) and may be connected to the second portion (320). For example, the end (321) of the second portion (320) may be positioned closer to the center (200) than the end (311) of the first portion (310) on the outside of the end (311) of the first portion (310), and the first connecting portion (330) may be configured to connect the end (321) of the second portion (320) from the end (311) of the first portion (310) toward the center (200).

[0066] Here, the same or similar effect as the embodiment of FIG. 1 can be obtained in the modified embodiment of FIG. 3 and the modified embodiment of FIG. 5.

[0067] Referring to FIGS. 2, 4, and 6 together, the second connecting portion (340) of the second portion (320) and the edge portion (100) can also be formed to be inclined. That is, it is connected to the edge portion (100) from the second portion (320) at an inclined angle.

[0068] In addition, the second connecting portion (340) includes a third inclined portion (341) on one side and a fourth inclined portion (342) on the other side, and the third inclined portion (341) and the fourth inclined portion (342) can be configured to have the same inclination in opposite directions.

[0069] That is, referring to FIG. 2, the third inclined portion (341) may be formed in the X direction, and the fourth inclined portion (342) may be formed in the Y direction. Here, the third inclined portion (341) may be formed parallel to the X direction, but is not necessarily required to be parallel, and the fourth inclined portion (342) may also be formed parallel to the Y direction, but is not necessarily required to be parallel.

[0070] By this structure, the third inclined portion (341) and the fourth inclined portion (342) can be formed symmetrically. Here, a through hole (350) can be formed between the third inclined portion (341) and the fourth inclined portion (342).

[0071] However, the first inclined portion (331) and the third inclined portion (341) may be parallel, but do not have to be parallel, and the second inclined portion (332) and the fourth inclined portion (342) may also be parallel, but do not have to be parallel.

[0072] In this way, when the width of the connection part (300) of the current collector plate (10) is formed to change, there is an effect in which the connection part (300) can be disconnected when a short-circuit current is applied without increasing the internal resistance of the battery cell.

[0073] That is, since the internal resistance of the battery cell does not increase due to the structure described above, the performance of the cylindrical battery cell (20) can be maintained, and when a short-circuit current is applied, the connection part (300) is disconnected to perform a fusing function, so the current flow is cut off and ignition does not occur.

[0074] FIG. 7 is a drawing showing test conditions of the collector plate of FIG. 1, FIGS. 8(a) to 8(C) are graphs of test results according to the test conditions of FIG. 7, and FIG. 9 is a drawing showing that fusing occurred in a test of the collector plate according to the embodiment of FIG. 1.

[0075] Referring to Fig. 7, three tests (#1, #2, #3) were conducted under the same conditions. The test conditions are as follows: First, the externally applied resistance is 5.08 [mΩ]. Then, the internal resistance of the battery cell in each of the three tests is 1.44 [mΩ], 1.45 [mΩ], and 1.42 [mΩ]. Then, the maximum current in each of the three tests is 749 [A], 764 [A], and 722 [A]. Then, the temperatures of the battery cells in each of the three tests at the start of the shutdown are 46.7 [℃], 42.3 [℃], and 45.3 [℃].

[0076] In all three tests, the internal resistance of the battery cell did not exceed 1.5 [mΩ].

[0077] Referring to Fig. 7, in each of the three tests, the fusing start times were 16.1 [sec], 16.5 [sec], and 17.2 [sec], and did not exceed 20 [sec] in any of the three tests. In this regard, the thick solid line (a1) on the left in Fig. 8(a) represents voltage, and the thick dotted line (a2) on the left represents current (the same applies to Figs. 8(b) and 8(c)). Referring to Figs. 8(a) to 8(c), it can be confirmed that fusing occurs at 16.1 [sec] and the voltage and current drop sharply in Fig. 8(a), fusing occurs at 16.5 [sec] and the voltage and current drop sharply in Fig. 8(b), and fusing occurs at 17.2 [sec] and the voltage and current drop sharply in Fig. 8(c).

[0078] That is, in the case of one embodiment of the present invention, it can be experimentally confirmed that it is possible to prevent overcurrent from flowing by having an appropriate fusing time.

[0079] And, referring back to FIG. 7, the external short circuit result was a pass in all three tests, where the pass external short circuit result means that when a short circuit current is applied to the battery cell, the internal resistance does not exceed a preset range (e.g., 1.5 [mΩ]) and within a preset time (e.g., 20 [sec]), fusing, i.e., the connection (300) is disconnected, and the battery cell does not catch fire or explode. Referring to FIG. 9, fusing (360) occurred near the connection point between the center (200) and the first portion (310).

[0080] Meanwhile, in Fig. 8(a), the thin dotted line (a3) ​​is the temperature of the positive tab of the cylindrical battery cell (20), the thin solid line (a4) is the temperature of the negative tab of the cylindrical battery cell (20), the single-dotted line (a5) is the temperature of the battery can (22, see Fig. 13) of the cylindrical battery cell (20), and the two-dotted line (a6) is the temperature of the venting part of the cylindrical battery cell (20) (same as Fig. 8(b) and Fig. 8(c)).

[0081] Referring to FIGS. 8(a) to 8(c), the temperature of the positive electrode tab rises slightly and then falls (see a3), and the temperature of the negative electrode tab, the temperature of the battery can (22), and the temperature of the venting portion are maintained within an appropriate range. That is, it can be experimentally confirmed that the temperature rise is not excessive according to the current collector plate according to one embodiment of the present invention, and thus, the cylindrical battery cell (20) does not ignite.

[0082] In conclusion, that is, the current collector plate according to one embodiment of the present invention has the effect of enabling smooth fusing by breaking the connection when a short-circuit current is applied without increasing the internal resistance of the battery cell, and also preventing ignition of the battery cell by blocking the flow of current due to the rupture of the connection of the current collector plate when a short-circuit current is applied.

[0083] FIG. 10 is a drawing showing a current collector plate according to a comparative example of each embodiment of the present invention, FIG. 11 is a drawing showing test conditions of the current collector plate of FIG. 10, and FIGS. 12(a) to 12(C) are graphs of test results according to the test conditions of FIG. 11.

[0084] Referring to Fig. 10, a current collector plate (11) is shown in which the width of the connecting portion (400) does not change.

[0085] Referring to Fig. 11, three tests (#1, #2, #3) were conducted under the same conditions as Fig. 7. The test conditions are as follows: First, the externally applied resistances of the three tests are 5.08 [mΩ], 5.23 [mΩ], and 5.3 [mΩ], respectively. In addition, the internal resistances of the battery cells of the three tests are 1.38 [mΩ], 1.42 [mΩ], and 1.37 [mΩ], respectively. In addition, the maximum currents of the three tests are 764 [A], 732 [A], and 754 [A], respectively. In addition, the temperatures of the battery cells of the three tests at the start of the shutdown are 89.6 [℃], 81.9 [℃], and 79.2 [℃], respectively.

[0086] In all three tests, the internal resistance of the battery cell did not exceed 1.5 [mΩ].

[0087] Here, the thick solid line (a7) on the left in Fig. 12(a) represents voltage, and the thick dotted line (a8) on the left represents current (the same applies to Figs. 12(b) and 12(c)). Referring to Figs. 12(a) to 12(c), the fusing start times in each of the three tests were 45.3[sec], 53.5[sec], and 44.8[sec], exceeding 20[sec] in all three tests.

[0088] That is, referring back to FIG. 11, the external short circuit result was a failure in all three tests, where the failure of the external short circuit result means that when a short circuit current is applied to the battery cell, fusing does not occur within a preset time (e.g., 20 [sec]), i.e., the connection (300) is not disconnected, which may eventually cause ignition or explosion in the battery cell.

[0089] In Fig. 12(a), the thin dotted line (a9) is the temperature of the positive tab of the cylindrical battery cell (20), the thin solid line (a10) is the temperature of the negative tab of the cylindrical battery cell (20), the single-dotted line (a11) is the temperature of the battery can (22, see Fig. 13) of the cylindrical battery cell (20), and the two-dotted line (a12) is the temperature of the venting part of the cylindrical battery cell (20) (same as Fig. 12(b) and Fig. 12(c)).

[0090] Referring to FIGS. 12(a) to 12(c), the temperature of the venting portion of the cylindrical battery cell (20) rises rapidly (see a12), and the temperature of the battery can (22) of the cylindrical battery cell (20) also rises (see a11). This means that ignition has occurred inside the cylindrical battery cell (20) and the flame is being discharged to the outside through the venting portion. In other words, it can be experimentally confirmed that the cylindrical battery cell is easily ignited by the current collector plate according to the prior art.

[0091] That is, in the case of the collector plate (10, see FIG. 1) according to one embodiment of the present invention, referring to FIGS. 7 to 9, the connection part (300) is disconnected within a preset time without the internal resistance of the cylindrical battery cell (20) exceeding a preset range, thereby preventing ignition or explosion of the cylindrical battery cell (20). However, in the case of the collector plate (11, see FIG. 10) of the comparative example, referring to FIGS. 11 and 12, although the internal resistance of the battery cell did not exceed a preset range, the battery cell ignited without the connection part (400) being disconnected within a preset time.

[0092] Accordingly, the current collector plate (10) according to one embodiment of the present invention has the effect of allowing the connection portion (300) to be disconnected when a short-circuit current is applied without increasing the internal resistance of the cylindrical battery cell (20), and also preventing the ignition of the cylindrical battery cell (20) by blocking the flow of current due to the breakage of the connection portion (300) of the current collector plate (10).

[0093] FIG. 13 is a schematic cross-sectional view of a cylindrical battery cell including a current collector plate according to each embodiment of the present invention.

[0094] A cylindrical battery cell (20) includes an electrode assembly (21), a battery can (22), a positive electrode collector plate (23), a cell terminal (24), and a negative electrode collector plate (25). Here, the positive electrode collector plate (23) of FIG. 13 may be the collector plate (10) according to the aforementioned embodiment of the present invention.

[0095] The electrode assembly (21) has a structure in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive and negative electrode plates are wound in one direction. In addition, a central hole is formed in the center of the electrode assembly (21), and can be formed in a jelly roll type.

[0096] For example, the electrode assembly (21) can be manufactured by winding a laminate formed by sequentially stacking a negative electrode plate, a separator, a positive electrode plate, and a separator at least once. Here, the positive electrode plate and the negative electrode plate can be formed in a sheet shape.

[0097] That is, the electrode assembly (21) applied to the present embodiment may be a coiled type electrode assembly (21). In this case, an additional separator may be provided on the outer circumferential surface of the electrode assembly (21) for insulation from the battery can (22). That is, the electrode assembly (21) may have a coiled structure well known in the relevant technical field without limitation.

[0098] A positive electrode plate may have a positive electrode active material applied to one or both surfaces thereof, and a first non-coated portion on which the positive electrode active material is not applied may be formed at an end of the positive electrode plate. Although FIG. 13 illustrates a positive electrode plate having a first non-coated portion formed thereon, the cylindrical battery cell (20) according to an embodiment of the present invention includes an embodiment of a positive electrode plate having no first non-coated portion formed thereon. However, for convenience of explanation, the following description will focus on a case where the first non-coated portion is formed on the positive electrode plate. The first non-coated portion may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (21), and may be used as an electrode tab in itself.

[0099] The negative electrode plate may have a negative active material applied to one or both surfaces, and a second non-coated portion formed at an end of the negative electrode plate where the negative active material is not applied. Although FIG. 13 illustrates a negative electrode plate having a second non-coated portion formed thereon, the cylindrical battery cell (20) according to an embodiment of the present invention includes an embodiment of a negative electrode plate in which the second non-coated portion is not formed. However, for convenience of explanation, the following description will focus on a case where the second non-coated portion is formed on the negative electrode plate. The second non-coated portion may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (21), and may be used as an electrode tab in itself.

[0100] That is, at least one of the positive and negative electrode plates may include a non-coated portion, which is not coated with an active material, at a long end in the winding direction. In addition, the first non-coated portion and the second non-coated portion may be configured to face in opposite directions.

[0101] Here, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be used without limitation as long as they are active materials known in the art.

[0102] In addition, the separation membrane may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., which may be used alone or in a laminated manner.

[0103] As another example, the separator may be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0104] At least one surface of the membrane may include a coating layer of inorganic particles. Furthermore, the membrane itself may be formed 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 an interstitial volume exists between adjacent particles.

[0105] In addition, the center hole of the electrode assembly (21) is also used for welding the cell terminal (24, positive terminal) and the positive current collector (23). That is, the electrode assembly (21) can be configured to weld the cell terminal (24) and the positive current collector (23) by irradiating a laser through the center hole.

[0106] Referring to Fig. 13, an electrode assembly (21) is housed in a battery can (22). In addition, a through hole may be formed in the battery can (22). For example, the battery can (22) may be formed in a cylindrical shape, and the electrode assembly (21) may be housed inside the battery can (22) and may be electrically connected to the negative electrode plate of the electrode assembly (21). Accordingly, the battery can (22) may have the same polarity as the negative electrode plate, i.e., a negative electrode.

[0107] Here, the diameter of the battery can (22) is formed to be larger than the diameter of the electrode assembly (21). A gap of a preset size is formed between the battery can (22) and the positive electrode collector plate (23), and an insulator may be interposed between the gap.

[0108] If the size of the electrode assembly (21) is increased while the size of the battery can (22) is determined according to the standard, the total capacity of the battery cell increases, but the gap between the battery can (22) and the electrode assembly (21) decreases.

[0109] That is, when the size of the electrode assembly (21) is increased to increase the overall capacity of the battery cell, the gap between the battery can (22) and the electrode assembly (21) decreases, so in order to increase the capacity of the battery cell, an insulator must be able to be interposed between the reduced gap between the battery can (22) and the electrode assembly (21), and for this purpose, it is desirable that the thickness of the insulator be as thin as possible.

[0110] The battery can (22) may be formed with a closed portion and an open portion positioned so as to face each other. For example, an open portion may be formed at the bottom of the battery can (22). The battery can (22) houses the electrode assembly (21) through the open portion formed at the bottom, and also, the electrolyte is injected through the open portion formed at the bottom of the battery can (22).

[0111] That is, the battery can (22) is a roughly cylindrical container having an opening formed at the bottom, and may be made of a conductive material such as metal, for example. The material of the battery can (22) may be made of a conductive metal such as aluminum, steel, stainless steel, etc., but is not limited thereto.

[0112] In addition, with reference to Fig. 13, a closed portion may be formed on the upper portion of the battery can (22). The closed portion may be partially formed on the opposite side of the open portion. A through hole is formed in the closed portion, and as shown in Fig. 13, a cell terminal (24) is coupled to the through hole and is electrically connected to the positive electrode collector plate (23) through the through hole. In addition, referring to Fig. 13, an insulator may be interposed between the battery can (22) on the closed portion side and the positive electrode collector plate (23).

[0113] The positive electrode collector plate (23) is electrically connected to the positive electrode plate, and for example, referring to FIG. 13, the positive electrode collector plate (23) is connected to the positive electrode plate at the top of the electrode assembly (21).

[0114] The positive electrode collector plate (23) is made of a conductive metal material and is connected to the first uncoated portion of the electrode assembly (21). The positive electrode collector plate (23) can be coupled to the upper portion of a joining surface formed by bending an end of the first uncoated portion in a direction parallel to the positive electrode collector plate (23). The bending direction of the first uncoated portion may be, for example, a direction toward the winding center (200) of the electrode assembly (21).

[0115] When the first non-conductive portion has a folded shape like this, the space occupied by the first non-conductive portion is reduced, which can lead to an improvement in energy density. In addition, the increased bonding area between the first non-conductive portion and the positive electrode current collector (23) can lead to an improvement in bonding strength and a reduction in resistance.

[0116] The cell terminal (24) is made of a conductive metal material, is coupled to a through hole formed in the closed portion of the battery can (22), and is electrically connected to the positive electrode collector plate (23) through the through hole. In addition, the cell terminal (24) is electrically connected to the positive electrode plate of the electrode assembly (21) through the positive electrode collector plate (23), thereby having a positive polarity.

[0117] That is, the cell terminal (24) can function as a positive terminal. In addition, the battery can (22) is electrically connected to the negative plate of the electrode assembly (21) as described above, thereby having a negative polarity.

[0118] The negative electrode collector plate (25) is connected to the second non-conductive portion of the electrode assembly (21). The negative electrode collector plate (25) is coupled to the lower portion of the electrode assembly (21). The negative electrode collector plate (25) is made of a conductive metal material such as aluminum, steel, copper, nickel, etc., and can be electrically connected to the second non-conductive portion of the negative electrode plate.

[0119] The negative electrode collector plate (25) can be electrically connected to the battery can (22). For this purpose, at least a portion of the edge portion of the negative electrode collector plate (25) can be fixed between the inner surface of the battery can (22) and the sealing gasket.

[0120] In one embodiment, at least a portion of the edge portion of the negative electrode current collector (25) may be supported by the lower surface of the bead portion (27) formed at the lower end of the battery can (22) and fixed to the bead portion (27) by welding. In a modified embodiment, at least a portion of the edge portion of the negative electrode current collector (25) may be directly welded to the inner wall surface of the battery can (22).

[0121] And, at least a portion of the remaining portion, excluding the joining portion of the beading portion (27) of the negative electrode collector plate (25), can be joined to the folded surface of the second non-conductive portion by welding, for example, laser welding.

[0122] Additionally, the negative electrode collector (25) may be electrically coupled to at least a portion of its edge to a surface adjacent to the crimping portion (28) among the upper and lower surfaces of the beading portion (27).

[0123] Referring to Fig. 13, the cap plate (26) is configured to seal the opening formed at the bottom of the battery can (22). The cap plate (26) may be made of, for example, a metal material to ensure rigidity.

[0124] In addition, the cap plate (26) may be provided as non-polar by being separated from the electrode assembly (21). That is, the cap plate (26) may not have polarity even if it is provided as a conductive metal material.

[0125] The fact that the cap plate (26) does not have polarity means that the cap plate (26) is electrically insulated from the battery can (22) and the cell terminal (24). As such, the cap plate (26) does not have to have polarity, and its material does not necessarily have to be a conductive metal.

[0126] The cap plate (26) can be supported by being seated on the beading portion (27) formed on the battery can (22). In addition, the cap plate (26) is fixed by the crimping portion (28). A sealing gasket may be interposed between the cap plate (26) and the crimping portion (28) of the battery can (22) to ensure airtightness of the battery can (22). That is, the sealing gasket may be arranged to be interposed between the edge of the cap plate (26) and the opening of the battery can (22).

[0127] A beading portion (27) and a crimping portion (28) can be formed at the bottom of the battery can (22).

[0128] The beading portion (27) is formed by pressing the outer circumference of the battery can (22) inward in an area adjacent to the opening of the battery can (22).

[0129] The beading portion (27) supports the electrode assembly (21) so that the electrode assembly (21), which has a size roughly corresponding to the width of the battery can (22), does not come out through the opening formed at the bottom of the battery can (22), and can also function as a support on which the cap plate (26) is mounted. In addition, the beading portion (27) can support the outer peripheral surface of the sealing gasket.

[0130] The crimping portion (28) is provided to extend and bend inwardly of the battery can (22) to wrap and secure the edge of the cap plate (26) together with the sealing gasket. Here, the crimping portion (28) is formed at the bottom of the battery can (22) based on the arrangement of the battery can (22). For example, when the battery can (22) is arranged such that the cell terminal (24) is positioned at the top as in FIG. 13, the crimping portion (28) is formed at the bottom of the battery can (22) based on FIG. 13. In addition, as in FIG. 13, the crimping portion (28) is formed at the bottom of the beading portion (27). However, this is only one embodiment, and the positions of the crimping portion (28) and the beading portion (27) are not limited thereto.

[0131] In addition, the present invention does not exclude a case where the battery can (22) does not have at least one of the beading portion (27) and the crimping portion (28). In the present invention, when the battery can (22) does not have at least one of the beading portion (27) and the crimping portion (28), fixing of the electrode assembly (21), fixing of the cap plate (26), or sealing of the battery can (22) can be realized through at least one of additional application of a component that can function as a stopper for the electrode assembly (21), additional application of a structure on which the cap plate (26) can be secured, and welding between the battery can (22) and the cap plate (26).

[0132] With reference to Fig. 13, the crimping portion (28) is formed at the lower portion of the beading portion (27). The crimping portion (28) has an extended and bent shape so as to wrap around the edge of the cap plate (26) positioned at the lower portion of the beading portion (27). By the shape of this folded crimping portion (28), the cap plate (26) is fixed on the beading portion (27).

[0133] Meanwhile, the battery can (22) of the present invention may not have at least one of the beading portion (27) and the crimping portion (28), in which case a sealing gasket may be interposed between a structure for fixing provided on the open side of the battery can (22) and the cap plate (26) to ensure airtightness of the battery can (22).

[0134] For example, it is also possible to omit the crimping portion (28) and fix the cap plate (26) by covering the opening of the battery can (22) through another fixing structure. For example, the applicant's published patent KR 10-2019-0030016 A discloses a cylindrical battery cell in which the beading portion (27) is omitted, and such a structure may be adopted in the present invention.

[0135] A vent notch (29) may be formed in the cap plate (26) so that it ruptures when the pressure inside the battery can (22) exceeds a threshold.

[0136] For example, the vent notch (29) may be formed on both sides of the cap plate (26), and may be formed in at least one pattern among a continuous circular pattern, a discontinuous circular pattern, and a linear pattern on the surface of the cap plate (26). In addition, the vent notch (29) may be formed in various other patterns.

[0137] The vent notch (29) is formed at the bottom of the battery can (22) based on the arrangement of the battery can (22) in FIG. 13, and may be arranged so that when the vent notch (29) is ruptured, gas inside the battery can (22) is discharged through the bottom of the battery can (22). For example, when the battery can (22) is arranged such that the cell terminal (24) is positioned at the top as in FIG. 13, the vent notch (29) may be formed at the bottom of the battery can (22) based on FIG. 13.

[0138] The vent notch (29) can be formed as an area having a thinner thickness compared to the surrounding area of ​​the cap plate (26).

[0139] The vent notch (29) is thinner than the surrounding area and thus may be more easily broken than the surrounding area, and when the internal pressure of the battery can (22) increases above a certain level, the vent notch (29) may be broken and gas generated inside the battery can (22) may be discharged.

[0140] For example, the vent notch (29) can be formed by partially reducing the thickness of the battery can (22) through notching on one side or both sides of the cap plate (26).

[0141] A cylindrical battery cell (20) according to one embodiment of the present invention may have a structure in which both a positive terminal and a negative terminal are present at the upper portion as shown in FIG. 13, and thus the upper portion structure is more complex than the lower portion structure.

[0142] Accordingly, a vent notch (29) may be formed on the cap plate (26) forming the lower surface of the cylindrical battery cell (20) to facilitate the discharge of gas generated inside the battery can (22).

[0143] In this way, if the gas generated inside the battery can (22) equipped in the cylindrical battery cell (20) is discharged downward, it can also be beneficial to the user's safety.

[0144] For example, if a cylindrical battery cell (20) is placed directly under the driver's seat in an electric vehicle, there may be a risk of safety accidents for the driver if the gas is discharged upward. However, if the gas is discharged downwards of the battery can (22), as in the cylindrical battery cell (20) according to one embodiment of the present invention, the above-mentioned problem does not occur even if the cylindrical battery cell (20) is placed directly under the driver's seat in an electric vehicle.

[0145] FIG. 14 is a schematic drawing showing the configuration of a battery pack including a cylindrical battery cell according to each embodiment of the present invention.

[0146] Referring to FIG. 14, a battery pack (30) according to one embodiment of the present invention may include one or more cylindrical battery cells (20) according to one embodiment of the present invention as described above. Here, the cylindrical battery cells (20) may include at least one current collector plate (10) according to one embodiment of the present invention as described above.

[0147] In addition, the battery pack (30) may further include a pack housing (31) for storing cylindrical battery cells (20), and various devices for controlling charging and discharging of the cylindrical battery cells (20), such as a BMS, a current sensor, a fuse, etc.

[0148] FIG. 15 is a drawing for explaining a vehicle including a battery pack according to each embodiment of the present invention.

[0149] Referring to FIG. 15, a vehicle (40) according to one embodiment of the present invention may include one or more cylindrical battery cells (20) or battery packs (30) according to each of the embodiments described above. In addition, the battery pack (30) includes cylindrical battery cells (20) according to each of the embodiments described above.

[0150] Here, the above-mentioned vehicle (40) includes various vehicles that are designed to use electricity, such as electric vehicles or hybrid vehicles.

[0151] In this specification, when terms indicating directions such as up, down, left, and right are used, these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the location of the target object or the location of the observer.

[0152] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and those skilled in the art to which the present invention pertains may make various modifications and variations within the scope of the technical spirit of the present invention and the equivalent scope of the claims to be described below. Therefore, the embodiments disclosed above should be considered in an illustrative rather than a restrictive sense. In other words, the true scope of the technical spirit of the present invention is set forth in the claims, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

[0153] The present invention relates to a current collector and a cylindrical battery cell including the same, and a battery pack and a vehicle including the cylindrical battery cell, and is particularly applicable to industries related to secondary batteries.

Claims

1. A current collector that electrically connects the electrode assembly housed inside a cylindrical battery cell. A border that defines the border; a central portion spaced apart from the above-mentioned edge portion and coupled to the electrode assembly; and A current collector plate comprising a connecting portion connecting the above-mentioned edge portion and the above-mentioned center portion, characterized in that the width of the connecting portion is formed to change.

2. In paragraph 1, A current collector plate characterized in that the above-mentioned border portion has a rim shape in which at least a portion of the inner area is empty.

3. In paragraph 1, A current collector plate characterized in that the connecting portion includes a first portion connected to the center portion and a second portion connected to the edge portion, and the width of the first portion is narrower than the width of the second portion.

4. In paragraph 3, A current collector plate characterized in that the first connecting portion of the first part and the second part is formed to be inclined.

5. In paragraph 4, A current collector plate, characterized in that the first connecting portion includes a first inclined portion on one side and a second inclined portion on the other side, and the first inclined portion and the second inclined portion are formed symmetrically to each other.

6. In paragraph 4, A current collector plate characterized in that the first connecting portion is formed to be inclined so as to extend from the first portion toward the second portion and is connected to the second portion.

7. In paragraph 6, The end of the second part is located further from the center than the end of the first part on the outside of the end of the first part, A current collector plate characterized in that the first connecting portion connects the end of the first portion and the end of the second portion from the end of the first portion toward the second portion.

8. In paragraph 4, A current collector plate characterized in that the first connecting portion is formed to be inclined so as to extend from the first portion toward the center and is connected to the second portion.

9. In paragraph 8, The end of the second part is located closer to the center than the end of the first part on the outside of the end of the first part, A current collector plate characterized in that the first connecting portion connects the end of the second portion from the end of the first portion toward the center.

10. In paragraph 3, A current collector plate characterized in that the first part and the second part are connected vertically to each other.

11. In paragraph 10, The end of the second part is located outside the end of the first part, The ends of the second part and the ends of the first part are located at the same distance from the center, A current collector plate characterized in that the first connecting portion connects an end of the first portion and an end of the second portion to each other.

12. In paragraph 3, A current collector plate characterized in that the second connecting portion of the second portion and the edge portion is formed to be inclined.

13. In paragraph 12, A current collector plate characterized in that the second connecting portion includes a third inclined portion on one side and a fourth inclined portion on the other side, and the third inclined portion and the fourth inclined portion are formed symmetrically.

14. In paragraph 13, A current collector plate characterized in that a through hole is formed between the third inclined portion and the fourth inclined portion.

15. A cylindrical battery cell comprising at least one current collector plate according to any one of claims 1 to 14.

16. In paragraph 15, A battery pack comprising at least one cylindrical battery cell.

17. In paragraph 15, A vehicle comprising at least one cylindrical battery cell.

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