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

Abstract

A current collector plate, a cylindrical battery cell including the current collector plate, and a battery pack and a vehicle including the cylindrical battery cell are disclosed. A current collector plate according to an embodiment of the present invention is a current collector plate for electrically connecting an electrode assembly housed in a cylindrical battery cell. The current collector plate includes: an edge portion defining an edge of the current collector plate; a central portion spaced apart from the edge portion and coupled to the electrode assembly; and a connecting portion for connecting the central portion to the edge portion, in which the width of the connecting portion varies.

Description

Technical Field

[0001] This application is based on and claims the priority of Korean Patent Application No. 10-2023-0101813, filed with the Korean Intellectual Property Office on August 3, 2023, and Korean Patent Application No. 10-2024-0037365, filed with the Korean Intellectual Property Office on March 18, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0002] The present disclosure relates to a current collector plate, a cylindrical battery cell including the current collector plate, and a battery pack and a vehicle including the cylindrical battery cell. More specifically, the present disclosure relates to such a current collector plate, a cylindrical battery cell including the current collector plate, and a battery pack and a vehicle including the cylindrical battery cell, wherein the current collector plate has a connection part that can be disconnected without increasing the internal resistance of the battery cell when a short-circuit current is applied. Background Art

[0003] Due to the characteristics of secondary batteries being easily applicable to various products and electrical characteristics such as high energy density, secondary batteries are widely used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric power sources.

[0004] Such secondary batteries have attracted attention due to the main advantages of significantly reducing the use of fossil fuels and not generating by-products of energy use, making them a new environmentally friendly and energy-saving energy source.

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

[0006] Therefore, when a higher output voltage is required, multiple battery cells can be connected in series to form a battery module or a battery pack. In addition, a battery module or a battery pack can be manufactured by connecting multiple battery cells in parallel according to the required charge / discharge capacity. Therefore, the number and electrical connection type of the battery cells included in the battery module or the battery pack can be set differently according to at least one of the required output voltage or charge / discharge capacity.

[0007] Meanwhile, secondary battery cells include cylindrical battery cells, prismatic battery cells, and pouch-type battery cells. A cylindrical battery cell is manufactured by winding a positive electrode plate and a negative electrode plate with an insulator or a separator interposed therebetween to form a wound core-type electrode assembly, and inserting the wound core-type electrode assembly together with an electrolyte into a battery can. In addition, a cylindrical battery cell can use a current collector plate to electrically connect the positive electrode plate and the negative electrode plate.

[0008] Meanwhile, recently, as cylindrical battery cells are used in electric vehicles, the form factor of the cylindrical battery cells has increased. That is, compared with cylindrical battery cells having 18650 and 21700 form factors, the diameter and height of the cylindrical battery cells have increased. The increase in the form factor has led to an increase in energy density, an enhancement in safety against thermal runaway, and an improvement in cooling efficiency.

[0009] Here, as the form factor increases, the need to protect the cylindrical battery cell from short-circuit current also increases. As an example, a fusing portion (e.g., a cut groove) can be formed on the current collector plate. However, when a short-circuit current is applied, simply forming a fusing portion on the current collector plate does not easily disconnect the connection portion of the current collector plate without increasing the internal resistance of the battery cell.

[0010] Generally, when the internal resistance of the battery cell increases, the internal resistance hinders the flow of current. Thus, when a short-circuit current is applied, the connection portion of the current collector plate does not disconnect, and the current continues to flow, eventually causing the battery cell to catch fire or explode.

[0011] Therefore, a structure is needed in which the current collector plate disconnects without increasing the internal resistance of the battery cell when a short-circuit current is applied. Summary of the Invention

[0012] Technical Problem

[0013] Accordingly, the present disclosure aims to provide a current collector plate, a cylindrical battery cell including the current collector plate, a battery pack including the cylindrical battery cell, and a vehicle, wherein the current collector plate has a connection portion that can be disconnected without increasing the internal resistance of the battery cell when a short-circuit current is applied.

[0014] In addition, the present disclosure aims to provide a current collector plate, a cylindrical battery cell including the current collector plate, a battery pack including the cylindrical battery cell, and a vehicle, which can prevent the battery cell from catching fire by blocking the flow of current caused by the rupture of the connection portion of the current collector plate when a short-circuit current is applied.

[0015] However, the technical problems to be solved by the present disclosure are not limited to the above problems, and those skilled in the art will clearly understand other problems not mentioned herein from the following description.

[0016] Technical Solution

[0017] In one aspect of the present disclosure, there is provided a current collector plate that is electrically connected to an electrode assembly housed in a cylindrical battery cell. The current collector plate includes: a boundary portion that defines a boundary; a central portion that is spaced apart from the boundary portion and is coupled to the electrode assembly; and a connection portion that is configured to connect the boundary portion and the central portion, and the connection portion is formed to have a varying width.

[0018] In an embodiment, the boundary portion may have an edge shape in which at least a part of its inner region is empty.

[0019] In an embodiment, the connecting portion may include a first portion connected to the central portion and a second portion connected to the boundary portion, and the width of the first portion is narrower than the width of the second portion.

[0020] In an embodiment, the first connecting portion between the first portion and the second portion may be formed to be inclined.

[0021] In an embodiment, the first connecting portion may include 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 with respect to each other.

[0022] In an embodiment, the first connecting portion may be inclinedly formed so as to expand from the first portion toward the second portion and may be connected to the second portion.

[0023] In an embodiment, outside the end of the first portion, the end of the second portion may be farther from the central portion than the end of the first portion, and the first connecting portion may 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.

[0024] In an embodiment, the first connecting portion may be inclinedly formed so as to expand from the first portion toward the central portion and may be connected to the second portion.

[0025] In an embodiment, outside the end of the first portion, the end of the second portion may be closer to the central portion than the end of the first portion, and the first connecting portion may connect the end of the second portion from the end of the first portion toward the central portion.

[0026] In an embodiment, the first portion and the second portion may be connected to each other perpendicularly.

[0027] In an embodiment, the end of the second portion may be positioned more outward than the end of the first portion, the end of the second portion and the end of the first portion may be positioned at the same distance from the central portion, and the first connecting portion may connect the end of the first portion and the end of the second portion to each other.

[0028] In an embodiment, the second connecting portion between the second portion and the boundary portion may be formed to be inclined.

[0029] In an embodiment, the second connecting portion may include 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.

[0030] In an embodiment, a through hole may be formed between the third inclined portion and the fourth inclined portion.

[0031] Meanwhile, according to another aspect of the present disclosure, a cylindrical battery cell including at least one current collector plate as described above may be provided; and a battery pack including at least one cylindrical battery cell as described above may also be provided; and a vehicle including at least one cylindrical battery cell as described above may also be provided.

[0032] Advantageous Effects

[0033] According to one aspect of the present disclosure, there is an effect that when a short-circuit current is applied, the connection portion can be disconnected without increasing the internal resistance of the battery cell.

[0034] In addition, there is an effect of preventing the battery cell from catching fire by blocking the current flow caused by the rupture of the connection portion of the current collector plate when a short-circuit current is applied.

[0035] However, the effects that can be obtained through the present disclosure are not limited to the above-described effects, and those skilled in the art will clearly understand other effects not mentioned herein from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a view showing a current collector plate according to an embodiment of the present disclosure.

[0037] Figure 2 is Figure 1 an enlarged view of part A of

[0038] Figure 3 is a view showing a current collector plate according to Figure 1 a modified embodiment of

[0039] Figure 4 is Figure 3 an enlarged view of part B of

[0040] Figure 5 is a view showing a current collector plate according to Figure 1 another modified embodiment of

[0041] Figure 6 is Figure 5 an enlarged view of part C of

[0042] Figure 7 is a view showing Figure 1 the test conditions of the current collector plate of

[0043] Figure 8 (a) to Figure 8 (C) are graphs showing the test results of the test conditions according to Figure 7 of

[0044] Figure 9 is a diagram showing a fuse break occurring in the test of a current collector plate according to Figure 1 the embodiment.

[0045] Figure 10 is a diagram showing a current collector plate of a comparative example according to each embodiment of the present disclosure.

[0046] Figure 11 is a diagram showing Figure 10 the test conditions of the current collector plate.

[0047] Figure 12 (a) to Figure 12 (C) are graphs showing the test results according to Figure 11 the test conditions.

[0048] Figure 13 is a schematic cross-sectional view of a cylindrical battery cell including a current collector plate according to each embodiment of the present disclosure.

[0049] Figure 14 is a schematic diagram showing the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present disclosure.

[0050] Figure 15 is a diagram for explaining a vehicle including a battery pack according to each embodiment of the present disclosure. Detailed Embodiments

[0051] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to the general meaning and dictionary meaning, but should be interpreted based on the meaning and concept corresponding to the technical aspects of the present disclosure on the basis of the principle that allows the inventor to appropriately define the terms for the best explanation. Therefore, the description presented herein is only a preferred example for illustrative purposes and is not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalent substitutions and modifications can be made without departing from the scope of the present disclosure.

[0052] In the drawings, for convenience and clarity of description, each component or the dimensions of a specific part constituting the component are enlarged, omitted, or schematically shown. Therefore, the dimensions of each component do not fully reflect the actual dimensions. If it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present disclosure, such a description will be omitted.

[0053] As used herein, the terms "coupled" or "connected" refer not only to the case where one member is directly coupled or directly connected to another member, but also to the case where one member is indirectly coupled or indirectly connected to another member through a joining member.

[0054] Figure 1 is a view showing a current collector plate according to an embodiment of the present disclosure, and Figure 2 is Figure 1 an enlarged view of part A of

[0055] The current collector plate 10 according to an embodiment of the present disclosure is configured to be electrically connected to an electrode assembly 21 (see Figure 13 ) accommodated inside a cylindrical battery cell 20 (see Figure 13 ). The cylindrical battery cell 20 will be described in detail later. The current collector plate 10 according to an embodiment of the present disclosure can be used as a positive current collector plate 23 (see Figure 13 ) of the cylindrical battery cell 20.

[0056] Referring to Figure 1 , the current collector plate 10 according to an embodiment of the present disclosure includes a boundary portion 100, a central portion 200, and a connection portion 300. The current collector plate 10 is configured to be electrically connected to an electrode assembly 2l accommodated inside a cylindrical battery cell 20.

[0057] The boundary portion 100 defines a boundary and may have an approximate edge shape, where at least a part of its inner region is empty to form an inner space. In Figure 1 , the boundary portion 100 is shown as having an approximate circular edge shape, but the shape of the boundary portion 100 is not limited thereto. Instead, the boundary portion 100 may have an approximate rectangular edge shape, a hexagonal edge shape, an octagonal edge shape, or other shapes. The boundary portion 100 may be coupled to the connection portion 300.

[0058] The central portion 200 is positioned inside the boundary portion 100 and is spaced apart from the boundary portion 100. For example, the central portion 200 may be positioned at the exact center of the inner space of the boundary portion 100, but is not limited thereto. In addition, the central portion 200 is coupled to the connection portion 300 and is connected to the boundary portion 100 through the connection 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 also the boundary portion 100 and the connection portion 300 may be coupled to the electrode assembly 21. In addition, the central portion 200 may be disposed at a position corresponding to the central hole of the electrode assembly 21.

[0059] The connection portion 300 connects the boundary portion 100 and the central portion 200. The connection portion 300 may be provided in a plurality, and the plurality of connection portions 300 may be spaced apart from each other. In Figure 1In this case, four connecting portions 300 are provided, but the number of the 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.

[0060] Refer to Figure 1 and Figure 2 , the connecting portion 300 may be formed to have a varying width. That is, the connecting portion 300 connects the boundary portion 100 and the central portion 200, and the width of the connecting portion 300 varies from the boundary portion 100 to the central portion 200 or from the central portion 200 to the boundary portion 100.

[0061] The connecting portion 300 may include a first portion 310 connected to the central portion 200 and a second portion 320 connected to the boundary portion 100. Refer to Figure 1 and Figure 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 increases from the narrower first portion 310 toward the second portion 320.

[0062] In addition, a first connecting portion 330 of the first portion 310 and the second portion 320 may be formed to be inclined. That is, the first connecting portion 330 is connected to be inclined from the first portion 310 toward the second portion 320.

[0063] In addition, refer to Figure 2 , the first connecting portion 330 may include a first inclined portion 331 located on one side and a second inclined portion 332 located 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, refer to Figure 2 , the first inclined portion 331 may be formed along the X direction, and the second inclined portion 332 may be formed along the Y direction. With this structure, the first inclined portion 331 and the second inclined portion 332 may be symmetrically formed.

[0064] Refer to Figure 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, an end portion 321 of the second portion 320 is outside an end portion 311 of the first portion 310 and is positioned farther from the central portion 200 than 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.

[0065] Figure 3 is a diagram showing a current collector plate according to a Figure 1 variant embodiment, and Figure 4 isFigure 3 An enlarged view of part B.

[0066] Referring to Figure 3 and Figure 4 , the end 321 of the second part 320 can be positioned more outward than the end 311 of the first part 310. The end 321 of the second part 320 and the end 311 of the first part 310 can be positioned at the same distance from the central part 200, and the first connecting part 330 can be configured to connect the end 311 of the first part 310 and the end 321 of the second part 320 to each other. Accordingly, the first part 310 and the second part 320 can be connected perpendicular to each other.

[0067] Figure 5 is a view showing a current collector plate according to another modified embodiment of Figure 1 , and Figure 6 is Figure 5 An enlarged view of part C.

[0068] Referring to Figure 5 and Figure 6 , the first connecting part 330 can be formed obliquely so as to extend from the first part 310 toward the central part 200 and can be connected to the second part 320. For example, the end 321 of the second part 320 is outside the end 311 of the first part 310 and can be positioned closer to the central part 200 than the end 311 of the first part 310, and the first connecting part 330 can be configured to connect the end 321 of the second part 320 from the end 311 of the first part 310 toward the central part 200.

[0069] Here, the same or similar effects as those of the embodiment of Figure 3 in the modified embodiment and Figure 5 in the modified embodiment can be obtained. Figure 1

[0070] Referring together to Figure 2 , Figure 4 and Figure 6 , the second connecting part 340 of the second part 320 and the boundary part 100 can also be formed obliquely. That is, the second connecting part 340 is connected so as to be inclined from the second part 320 toward the boundary part 100.

[0071] In addition, the second connecting part 340 includes a third inclined part 341 on one side and a fourth inclined part 342 on the other side, and the third inclined part 341 and the fourth inclined part 342 can be configured to have the same inclination in opposite directions.

[0072] That is, referring to Figure 2, the third inclined portion 341 may be formed along the X direction, and the fourth inclined portion 342 may be formed along the Y direction. Here, the third inclined portion 341 may be formed parallel to the X direction, but it is not necessarily required to be parallel, and the fourth inclined portion 342 may also be formed parallel to the Y direction, but it is not necessarily required to be parallel.

[0073] Due to this structure, the third inclined portion 341 and the fourth inclined portion 342 may be formed symmetrically. Here, a through hole 350 may be formed between the third inclined portion 341 and the fourth inclined portion 342.

[0074] However, the first inclined portion 331 and the third inclined portion 341 may be parallel, but it is not necessarily required to be parallel, and the second inclined portion 332 and the fourth inclined portion 342 may also be parallel, but it is not necessarily required to be parallel.

[0075] If the connecting portion 300 of the current collector plate 10 is formed in this way to have a varying width, there is an effect that the connecting portion 300 can be disconnected without increasing the internal resistance of the battery cell when a short-circuit current is applied.

[0076] That is, since the internal resistance of the battery cell does not increase due to the above structure, the performance of the cylindrical battery cell 20 can be maintained, and when a short-circuit current is applied, the connecting portion 300 is disconnected to perform a fusing function, thereby preventing the current flow from being cut off and preventing a fire from occurring.

[0077] Figure 7 is a diagram showing Figure 1 the test conditions of the current collector plate, Figure 8 (a) to Figure 8 (C) are graphs showing the test results according to Figure 7 the test conditions, and Figure 9 is a diagram showing fusing occurring in the test of the current collector plate according to the Figure 1 embodiment.

[0078] Referring to Figure 7 , three tests (#1, #2, #3) were conducted under the same conditions. Regarding the test conditions, first, the externally applied resistance was 5.08 mΩ. In addition, in each of the three tests, the internal resistance of the battery cell was 1.44 mΩ, 1.45 mΩ, and 1.42 mΩ. In addition, the maximum current in the three tests was 749 A, 764 A, and 722 A. In addition, at the start of shutdown in the three tests, the temperature of the battery cell was 46.7 °C, 42.3 °C, and 45.3 °C.

[0079] In all three tests, the internal resistance of the battery cell did not exceed 1.5 mΩ.

[0080] Referring to Figure 7, the fuse start times in each of the three tests were 16.1 seconds, 16.5 seconds, and 17.2 seconds, and none exceeded 20 seconds in any of the three tests. In this regard, Figure 8 (a) The thick solid line (a1) on the left represents voltage, and the thick dashed line (a2) on the left represents current (the same applies to Figure 8 (b) and Figure 8 (c)). Referring to Figure 8 (a) to Figure 8 (c), in Figure 8 (a), it can be confirmed that a fuse occurs at 16.1 seconds and the voltage and current drop sharply. In Figure 8 (b), it can be confirmed that a fuse occurs at 16.5 seconds and the voltage and current drop sharply. And in Figure 8 (c), it can be confirmed that a fuse occurs at 17.2 seconds and the voltage and current drop sharply.

[0081] That is, it can be experimentally confirmed that, due to providing an appropriate fuse time in the embodiments of the present disclosure, overcurrent flow can be prevented.

[0082] In addition, referring again to Figure 7 , the external short - circuit results passed in all three tests. Here, the passing of the 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 a fuse (i.e., disconnection of the connecting portion 300) occurs within a preset time (e.g., 20 seconds), so that the battery cell does not catch fire or explode. Referring to Figure 9 , the fuse 360 occurs near the connection point between the central portion 200 and the first portion 310.

[0083] Meanwhile, in Figure 8 (a), the thin dashed line (a3) is the temperature of the positive terminal of the cylindrical battery cell 20, the thin solid line (a4) is the temperature of the negative terminal of the cylindrical battery cell 20, the single - dotted line (a5) is the temperature of the battery can 22 of the cylindrical battery cell 20 (see Figure 13 ), and the double - dotted line (a6) is the temperature of the exhaust portion of the cylindrical battery cell 20 (the same applies to Figure 8 (b) and Figure 8 (c)).

[0084] Referring to Figure 8 (a) to Figure 8 (c), the temperature of the positive terminal rises slightly and then drops (see a3), and the temperatures of the negative terminal, the battery can 22, and the exhaust portion remain within an appropriate range. That is, according to the embodiments of the present disclosure, it can be experimentally confirmed that the temperature rise is not excessive, so the cylindrical battery cell 20 does not catch fire.

[0085] Finally, that is, the current collector plate according to the embodiments of the present disclosure has the following effects: when a short-circuit current is applied, smooth fusing is achieved by disconnecting the connection part without increasing the internal resistance of the battery cell, and also, when a short-circuit current is applied, the flow of current is blocked due to the rupture of the connection part of the current collector plate to prevent the battery cell from catching fire.

[0086] Figure 10 It is a diagram showing a current collector plate of a comparative example according to each embodiment of the present disclosure, Figure 11 It is showing Figure 10 the test conditions of the current collector plate, and Figure 12 (a) to Figure 12 (C) of is a graph showing the test results according to Figure 11 the test conditions.

[0087] Referring to Figure 10 , a current collector plate 11 with a constant width of the connection part 400 is shown.

[0088] Referring to Figure 11 , three tests (#1, #2, #3) are conducted under the same conditions as Figure 7 . Regarding the test conditions, first, the externally applied resistances for each of the three tests are 5.08 mΩ, 5.23 mΩ, and 5.3 mΩ. In addition, the internal resistances of the battery cells for each of the three tests are 1.38 mΩ, 1.42 mΩ, and 1.37 mΩ. In addition, the maximum currents for each of the three tests are 764 A, 732 A, and 754 A. In addition, the temperatures of the battery cells at the start of shutdown for each of the three tests are 89.6 °C, 81.9 °C, and 79.2 °C.

[0089] In all three tests, the internal resistance of the battery cell does not exceed 1.5 mΩ.

[0090] Here, Figure 12 (a) The thick solid line (a7) on the left represents voltage, and the thick dashed line (a8) on the left represents current (similarly applicable to Figure 12 (b) and Figure 12 (c)). Referring to Figure 12 (a) to Figure 12 (c), the fusing start times in each of the three tests are 45.3 seconds, 53.5 seconds, and 44.8 seconds, all of which exceed 20 seconds in the three cases.

[0091] That is, referring back to Figure 11, the external short - circuit result was a failure in all three tests. Here, the failure of the external short - circuit result means that when a short - circuit current is applied to the battery cell, no fusing occurs within a preset time (e.g., 20 seconds) (i.e., the connecting portion 300 does not disconnect), which may ultimately lead to the ignition or explosion of the battery cell.

[0092] In Figure 12 (a), the fine dashed line (a9) is the temperature of the positive electrode terminal of the cylindrical battery cell 20, the fine solid line (a10) is the temperature of the negative electrode terminal of the cylindrical battery cell 20, the single - dotted line (a11) is the temperature of the battery can 22 of the cylindrical battery cell 20 (see Figure 13 ), and the double - dotted line (a12) is the temperature of the exhaust portion of the cylindrical battery cell 20 (the same applies to Figure 12 (b) and Figure 12 (c)).

[0093] Referring to Figure 12 (a) to Figure 12 (c), the temperature of the exhaust 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), which indicates that a fire occurs inside the cylindrical battery cell 20 and the flame is discharged to the outside through the exhaust portion. That is to say, regarding the current collector plate according to the prior art, it can be experimentally confirmed that the cylindrical battery cell is prone to catching fire.

[0094] That is to say, in the case of the current collector plate 10 according to the embodiments of the present disclosure (see Figure 1 ), referring to Figures 7 to 9 , when the internal resistance of the cylindrical battery cell 20 does not exceed a preset range, the connecting portion 300 disconnects within a preset time, thereby preventing the cylindrical battery cell 20 from catching fire or exploding. However, in the case of the current collector plate 11 of the comparative example (see Figure 10 ), referring to Figure 11 and Figure 12 , although the internal resistance of the battery cell does not exceed the preset range, since the connecting portion 400 does not disconnect within the preset time, the battery cell catches fire.

[0095] Therefore, when a short - circuit current is applied, the current collector plate 10 according to the embodiments of the present disclosure can disconnect the connecting portion 300 without increasing the internal resistance of the cylindrical battery cell 20, and also has the effect of preventing the cylindrical battery cell 20 from catching fire by blocking the flow of current caused by the rupture of the connecting portion 300 of the current collector plate 10.

[0096] Figure 13 is a schematic cross - sectional view showing a cylindrical battery cell including a current collector plate according to each embodiment of the present disclosure.

[0097] The cylindrical battery cell 20 includes an electrode assembly 21, a battery can 22, a positive current collector plate 23, a battery cell terminal 24, and a negative current collector plate 25. Here, Figure 13 the positive current collector plate 23 may be the current collector plate 10 according to the embodiment of the present disclosure above.

[0098] The electrode assembly 21 has a structure in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction. In addition, a central hole is formed at the center of the electrode assembly 21, and the electrode assembly 21 may be formed in a wound core type.

[0099] For example, the electrode assembly 21 may be manufactured by winding a laminate formed by laminating a negative electrode plate, a separator, a positive electrode plate, and a separator at least once in sequence. Here, the positive electrode plate and the negative electrode plate may be formed in a sheet shape.

[0100] That is, the electrode assembly 21 applied to this embodiment may be a wound type electrode assembly 21. In this case, an additional separator for insulating from the battery can 22 may be provided on the outer surface of the electrode assembly 21. That is, the electrode assembly 21 may have a wound structure well known in the art without limitation.

[0101] The positive electrode active material may be coated on one or both surfaces of the positive electrode plate, and a first uncoated portion where the positive electrode active material is not coated may be formed at the end of the positive electrode plate. Although Figure 13 shows the positive electrode plate formed with the first uncoated portion, the cylindrical battery cell 20 according to the embodiment of the present disclosure includes an embodiment in which the positive electrode plate without the first uncoated portion is formed. However, for the sake of convenience of description, the following description will focus on the case where the first uncoated portion is formed on the positive electrode plate. The first uncoated 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 it may itself be used as an electrode connection.

[0102] The negative electrode active material may be coated on one or both surfaces of the negative electrode plate, and a second uncoated portion where the negative electrode active material is not coated may be formed at the end of the negative electrode plate. Although Figure 13 shows the negative electrode plate formed with the second uncoated portion, the cylindrical battery cell 20 according to the embodiment of the present disclosure also includes an embodiment in which the negative electrode plate without the second uncoated portion is formed. However, for the sake of convenience of description, the following description will focus on the case where the second uncoated portion is formed on the negative electrode plate. The second uncoated 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 it may itself be used as an electrode connection.

[0103] That is to say, at least one of the positive electrode plate and the negative electrode plate may include an uncoated portion where the active material is not coated along the long side ends in the winding direction. In addition, the first uncoated portion and the second uncoated portion may be configured to face opposite directions.

[0104] 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 use any active material known in the art without limitation.

[0105] The separator may include a porous polymer membrane, for example, a porous polymer membrane made of a polyolefin-based polymer, such as a homopolymer of ethylene, a homopolymer of propylene, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer that can be used alone or in layers.

[0106] As another example, the separator may include a common porous non-woven fabric, such as a non-woven fabric made of high melting point glass fibers and polyethylene terephthalate fibers.

[0107] The separator may have an inorganic particle coating on at least one of its surfaces. In addition, the separator itself may be a coating of inorganic particles. The particles forming the coating may be bonded to each other with an adhesive to create an interstitial volume between adjacent particles.

[0108] In addition, the central hole of the electrode assembly 21 is also used to weld the battery cell terminal (positive terminal) 24 and the positive current collector plate 23. That is to say, the battery cell terminal 24 and the positive current collector plate 23 can be welded by irradiating a laser through the central hole of the electrode assembly 21.

[0109] Refer to Figure 13 , the electrode assembly 21 is accommodated in the 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 accommodated inside the battery can 22 and may be electrically connected to the negative electrode plate of the electrode assembly 21. Therefore, the battery can 22 may have the same polarity (i.e., negative polarity) as the negative electrode plate.

[0110] Here, the diameter of the battery can 22 is 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 current collector plate 23, and an insulator may be inserted into the gap.

[0111] When the size of the battery can 22 is set according to a preset standard, as the size of the electrode assembly 21 increases, the total capacity of the battery cell increases, but the gap between the battery can 22 and the electrode assembly 21 decreases.

[0112] That is to say, the gap between the battery can 22 and the electrode assembly 21 decreases as the size of the electrode assembly 21 increases, so as to increase the total capacity of the battery cell. In order to increase the capacity of the battery cell, an insulator needs to be disposed in the reduced gap between the battery can 22 and the electrode assembly 21. For this purpose, the thickness of the insulator is preferably as small as possible.

[0113] The battery can 22 may have a closed portion and an opening portion opposite to each other. For example, based on Figure 4 , the battery can 22 may have an opening portion at the bottom. The electrode assembly 21 is accommodated through the opening portion at the bottom of the battery can 22, and the electrolyte is injected through the opening portion at the bottom of the battery can 22.

[0114] That is to say, the battery can 22 is an approximately cylindrical container with an opening portion at the bottom and is made of a conductive material such as metal. The battery can 22 can be made of conductive metals such as aluminum, steel, and stainless steel, but is not limited thereto.

[0115] In addition, referring to Figure 13 , a closed portion can be formed at the upper part of the battery can 22. The closed portion can be partially formed on the side opposite to the opening portion. A through hole is formed in the closed portion, and as Figure 13 shown, the battery cell terminal 24 is connected to the through hole and is electrically connected to the positive current collector plate 23 through the through hole. In addition, referring to Figure 13 , the insulator can be inserted between the battery can 22 and the positive current collector plate 23 at the closed portion.

[0116] The positive current collector plate 23 is electrically connected to the positive electrode plate. For example, referring to Figure 13 , the positive current collector plate 23 is connected to the positive electrode plate at the upper part of the electrode assembly 21.

[0117] The positive current 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 current collector plate 23 can be connected to the upper part of the connection surface formed by bending the end of the first uncoated portion in a direction parallel to the positive current collector plate 23. The bending direction of the first uncoated portion can be, for example, a direction towards the winding center portion 200 of the electrode assembly 21.

[0118] When the first uncoated portion has such a bent shape, the space occupied by the first uncoated portion is reduced, which may lead to an increase in energy density. In addition, as the connection area between the first uncoated portion and the positive current collector plate 23 increases, this may lead to an increase in connection strength and a decrease in resistance.

[0119] The battery cell terminal 24 is made of a conductive metal material and is connected to a through hole formed in the closed portion of the battery can 22, and is electrically connected to the positive current collector plate 23 through the through hole. In addition, the battery cell terminal 24 is electrically connected to the positive electrode plate of the electrode assembly 21 through the positive current collector plate 23, so as to have a positive polarity.

[0120] That is to say, the battery cell terminal 24 can be used as the positive terminal. In addition, as described above, the battery can 22 is electrically connected to the negative electrode plate of the electrode assembly 21, so as to have a negative polarity.

[0121] The negative current collector plate 25 is connected to the second uncoated portion of the electrode assembly 21. The negative current collector plate 25 is connected to the lower portion of the electrode assembly 21. The negative current collector plate 25 is made of a conductive metal material such as aluminum, steel, copper or nickel, and can be electrically connected to the second uncoated portion of the negative electrode plate.

[0122] The negative current collector plate 25 can be electrically connected to the battery can 22. For this purpose, at least a part of the boundary portion of the negative current collector plate 25 can be inserted and fixed between the inner surface of the battery can 22 and the gasket.

[0123] In an embodiment, at least a part of the boundary portion of the negative current collector plate 25 can be supported on the lower surface of the crimped portion 27 formed at the lower end of the battery can 22, and is fixed to the crimped portion 27 by welding. In a variant embodiment, at least a part of the boundary portion of the negative current collector plate 25 can be directly welded to the inner wall surface of the battery can 22.

[0124] In addition, except for the connecting portion of the crimped portion 27 of the negative current collector plate 25, at least a part of the remaining portion can be connected to the curved surface of the second uncoated portion by welding (for example, laser welding).

[0125] In addition, at least a part of the edge of the negative current collector plate 25 can be electrically connected to the surface of the upper surface and the lower surface of the crimped portion 27 adjacent to the hemming portion 28.

[0126] Referring to Figure 13 , the cover plate 26 is configured to seal the opening formed at the lower end of the battery can 22. The cover plate 26 can be made of, for example, a metal material to ensure rigidity.

[0127] In addition, the cover plate 26 can be set to be non-polar by being separated from the electrode assembly 21. That is to say, even if the cover plate 26 is made of a conductive metal material, the cover plate 26 may not have a polarity.

[0128] The non-polarity of the cover plate 26 means that the cover plate 26 is electrically insulated from the battery can 22 and the battery cell terminal 24. In this way, the cover plate 26 can not be polarized, and its material does not necessarily have to be a conductive metal.

[0129] The cover plate 26 can be placed on and supported by the curled edge portion 27 formed at the battery can 22. In addition, the cover plate 26 is fixed by the crimping portion 28. A gasket can be inserted between the cover plate 26 and the crimping portion 28 of the battery can 22 to ensure the airtightness of the battery can 22. That is, the gasket can be arranged to be inserted between the edge of the cover plate 26 and the opening portion of the battery can 22.

[0130] The battery can 22 may include a curled edge portion 27 and a crimping portion 28 at the lower part.

[0131] The curled edge portion 27 is formed by curling the periphery of the outer peripheral surface of the battery can 22 inward in a region adjacent to the opening portion of the battery can 22.

[0132] The curled edge portion 27 can support the electrode assembly 21 to prevent the electrode assembly 21 having a size substantially corresponding to the width of the battery can 22 from slipping out of the opening formed at the bottom of the battery can 22, and serves as a support for placing the cover plate 26 thereon. In addition, the curled edge portion 27 can support the outer peripheral surface of the gasket.

[0133] The crimping portion 28 extends and bends to the inside of the battery can 22 to fix the cover plate 26 together with the gasket around the edge of the cover plate 26. Here, based on the placement of the battery can 22, the crimping portion 28 is formed at the lower part of the battery can 22. For example, as Figure 13 shown when the battery can 22 is positioned such that the battery cell terminal 24 is provided at the upper part, the crimping portion 28 is formed at the lower part of the battery can 22 based on Figure 13 this. In addition, as Figure 13 shown, the crimping portion 28 is formed below the curled edge portion 27. However, this is only one embodiment, and the positions of the crimping portion 28 and the curled edge portion 27 are not limited thereto.

[0134] In addition, the present disclosure does not exclude a battery can 22 that does not include at least one of the curled edge portion 27 and the crimping portion 28. In the present disclosure, when the battery can 22 does not include at least one of the curled edge portion 27 and the crimping portion 28, the fixing of the electrode assembly 21, the fixing of the cover plate 26, or the sealing of the battery can 22 can be achieved by at least one of the additional application of a component serving as a stopper for the electrode assembly 21, the additional application of a structure for placing the cover plate 26 thereon, and the welding between the battery can 22 and the cover plate 26.

[0135] Based on Figure 13 this, the crimping portion 28 is formed below the curled edge portion 27. The crimping portion 28 extends and bends around the edge of the cover plate 26 provided below the curled edge portion 27. Through the bent shape of the crimping portion 28, the cover plate 26 is fixed above the curled edge portion 27.

[0136] Meanwhile, the battery can 22 of the present disclosure may not have at least one of a curled edge portion 27 and a crimped edge portion 28, and in such a case, a gasket may be inserted between a fixing structure provided at an opening portion of the battery can 22 and a cover plate 26 to ensure the airtightness of the battery can 22.

[0137] For example, the crimped edge portion 28 may be omitted, and any other fixing structure may be used to fix the cover plate 26 covering the opening portion of the battery can 22. For example, the applicant's patent disclosure KR10-2019-0030016A discloses a cylindrical battery cell in which the curled edge portion 27 is omitted, and such a structure may be adopted in the present disclosure.

[0138] The cover plate 26 may include an exhaust notch 29 which is designed to rupture when the internal pressure of the battery can 22 is higher than a threshold value.

[0139] For example, the exhaust notch 29 may be formed on two surfaces of the cover plate 26, and may be formed as at least one of a continuous circular pattern, a discontinuous circular pattern, or a linear pattern on the surface of the cover plate 26. In addition, the exhaust notch 29 may be formed in various different patterns.

[0140] Based on Figure 13 the placement of the battery can 22, the exhaust notch 29 may be formed at the bottom of the battery can 22, and when the exhaust notch 29 ruptures, the gas in the battery can 22 may be discharged through the bottom of the battery can 22. For example, as Figure 13 shown when the battery can 22 is positioned such that the battery cell terminal 24 is provided at the upper portion, the exhaust notch 29 may be Figure 13 formed at the bottom of the battery can 22.

[0141] The exhaust notch 29 may be an area having a thickness less than any other area of the cover plate 26.

[0142] Since the exhaust notch 29 is thinner than the surrounding area, the exhaust notch 29 may be more likely to rupture than the surrounding area, and when the internal pressure of the battery can 22 is equal to or higher than a predetermined level, the exhaust notch 29 may rupture to discharge the gas inside the battery can 22.

[0143] For example, the exhaust notch 29 may be formed by partially reducing the thickness of the battery can 22 by grooving on one or both surfaces of the cover plate 26.

[0144] The cylindrical battery cell 20 according to an embodiment of the present disclosure may have such a structure in which the positive terminal and the negative terminal are Figure 13 arranged at the upper portion, resulting in a more complex upper structure than the lower structure.

[0145] Therefore, in order to smoothly discharge the gas inside the battery can 22, the cover plate 26 forming the lower surface of the cylindrical battery cell 20 may have an exhaust notch 29.

[0146] As described above, when the gas inside the battery can 22 provided in the cylindrical battery cell 20 is discharged downward, this may be beneficial to the safety of the user.

[0147] For example, in the case where the cylindrical battery cell 20 is directly below the driver's seat in an electric vehicle, when the gas is discharged upward, there may be a risk of a safety accident for the driver. However, when the gas is discharged through the bottom of the battery can 22 as in the cylindrical battery cell 20 according to an embodiment of the present disclosure, in the case where the cylindrical battery cell 20 is directly below the driver's seat in an electric vehicle, the above problem does not occur.

[0148] Figure 14 is a schematic diagram showing the configuration of a battery pack including a cylindrical battery cell according to each embodiment of the present disclosure.

[0149] Referring to Figure 14 , the battery pack 30 according to an embodiment of the present disclosure may include at least one cylindrical battery cell 20 according to the embodiment of the present disclosure as described above. Here, according to the embodiment of the present disclosure as described above, the cylindrical battery cell 20 may include at least one current collector plate 10.

[0150] In addition, the battery pack 30 may further include a battery pack housing 31 for accommodating the cylindrical battery cell 20, and various devices (such as a BMS, a current sensor, a fuse, etc.) for controlling the charging and discharging of the cylindrical battery cell 20.

[0151] Figure 15 is a diagram for explaining a vehicle including a battery pack according to each embodiment of the present disclosure.

[0152] Referring to Figure 15 , the vehicle 40 according to an embodiment of the present disclosure may include at least one cylindrical battery cell 20 or at least one battery pack 30 according to each of the above embodiments. In addition, the battery pack 30 includes a cylindrical battery cell 20 according to each of the above embodiments.

[0153] Here, the vehicle 40 includes various vehicles designed to use electricity (for example, electric vehicles or hybrid electric vehicles).

[0154] When the terms indicating directions used herein (for example, up, down, left, and right) are used only for the convenience of description, these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may change according to the position of the described element or observer.

[0155] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, although indicating preferred embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art from the detailed description. Accordingly, the foregoing disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. In other words, the scope of the true technical idea of the present disclosure is shown in the claims, and all differences within the equivalent scope should be construed as being included in the present disclosure.

[0156] Industrial Applicability

[0157] The present disclosure relates to a current collector plate, a cylindrical battery cell including the current collector plate, a battery pack and a vehicle including the cylindrical battery cell, and can be particularly used in industries related to secondary batteries.

Claims

1. A current collector plate, the current collector plate being electrically connected to an electrode assembly housed in a cylindrical battery cell, the current collector plate comprising: A boundary portion that defines a boundary; A central portion that is spaced apart from the boundary portion and is connected to the electrode assembly; And A connecting portion configured to connect the boundary portion and the central portion, the connecting portion being formed with a varying width.

2. The current collector plate according to claim 1, Among them, The boundary portion has an edge shape in which at least a part of its inner region is empty.

3. The current collector plate according to claim 1, Among them, The connecting portion includes a first part connected to the central portion and a second part connected to the boundary portion, and the width of the first part is narrower than the width of the second part.

4. The current collector plate according to claim 3, Among them, A first connecting portion between the first part and the second part is formed to be inclined.

5. The current collector plate according to claim 4, Among them, 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 with respect to each other.

6. The current collector plate according to claim 4, Among them, The first connecting portion is inclined to expand from the first part toward the second part and is connected to the second part.

7. The current collector plate according to claim 6, Among them, An end of the second part is outside an end of the first part and is positioned farther from the central portion than the end of the first part, and wherein the first connecting portion connects the end of the first part and the end of the second part from the end of the first part toward the second part.

8. The current collector plate according to claim 4, Among them, The first connecting portion is inclined to expand from the first part toward the central portion and is connected to the second part.

9. The current collector plate according to claim 8, Among them, An end of the second part is outside an end of the first part and is positioned closer to the central portion than the end of the first part, and wherein the first connecting portion connects the end of the second part from the end of the first part toward the central portion.

10. The current collector plate according to claim 3, Among them, The first part and the second part are connected to each other perpendicularly.

11. The current collector plate according to claim 10, Among them, An end of the second part is positioned more outward than an end of the first part, wherein the end of the second part and the end of the first part are positioned at the same distance from the central portion, and wherein the first connecting portion connects the end of the first part and the end of the second part to each other.

12. The current collector plate according to claim 3, Among them, A second connecting portion between the second part and the boundary portion is formed to be inclined.

13. The current collector plate according to claim 12, Among them, 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. The current collector plate according to claim 13, Among them, A through hole is formed between the third inclined portion and the fourth inclined portion.

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

16. A battery pack, the battery pack comprising at least one cylindrical battery cell according to claim 15.

17. A vehicle, the vehicle comprising at least one cylindrical battery cell according to claim 15.

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