Current collector plate and cylindrical battery cell containing it, battery pack containing the cylindrical battery cell and automobile

Abstract

A current collector plate and a cylindrical battery cell including the same, a battery pack including the cylindrical battery cell and an automobile are disclosed. A current collector plate according to one embodiment of the present invention is a current collector plate that electrically connects an electrode assembly housed inside a cylindrical battery cell, and includes a peripheral portion that defines the periphery, a central portion that is separated from the peripheral portion and connects with the electrode assembly, and a connecting portion that connects the peripheral portion and the central portion, wherein the width of the connecting portion is formed to vary.

Description

TECHNICAL FIELD

[0001] This application claims priority based on 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, and all the content disclosed in the specifications and drawings of the said applications is incorporated herein by reference.

[0002] The present invention relates to a current collector plate, a cylindrical battery cell including the same, a battery pack including the cylindrical battery cell, and a vehicle. More specifically, the present invention relates to a current collector plate in which a connection part breaks when a short-circuit current is applied without increasing the internal resistance of the battery cell, a cylindrical battery cell including the same, a battery pack including the cylindrical battery cell, and a vehicle.

BACKGROUND ART

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

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

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

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

[0007] In addition, cylindrical, prismatic, and pouch-type battery cells are known types of secondary battery cells. In the case of cylindrical battery cells, an insulating separator membrane is interposed between the positive and negative electrodes, and this is wound up to form an electrode assembly in the form of a jelly roll, which is then placed in a battery case together with the electrolyte to constitute the battery. A current collector plate may be used to electrically connect the positive and negative electrodes of the cylindrical battery cell.

[0008] On the other hand, as cylindrical battery cells are increasingly being applied to electric vehicles, their form factor is expanding. 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, greater safety against thermal runaway, and improved cooling efficiency.

[0009] As the form factor increases, the need to protect cylindrical battery cells from short-circuit currents and other factors also increases. For example, a fuse section (e.g., a notched groove) can be formed on the current collector plate. However, simply forming a fuse section on the current collector plate does not easily cause the connection portion of the current collector plate to break smoothly 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 obstructs the flow of current, preventing the current collector plate from breaking when a short-circuit current is applied. This allows the current to continue flowing, eventually leading to the battery cell catching fire or exploding.

[0011] Therefore, a structure is needed in which the current collector plate easily breaks when a short-circuit current is applied without increasing the internal resistance of the battery cell. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The present invention aims to provide a current collector plate whose connecting portion breaks when a short-circuit current is applied without increasing the internal resistance of the battery cell, a cylindrical battery cell including the same, a battery pack including the cylindrical battery cell, and an automobile.

[0013] Another objective is to provide a current collector plate capable of preventing the battery cell from igniting by interrupting the flow of current through the breakage of the connecting portion of the current collector plate when a short-circuit current is applied, a cylindrical battery cell including the same, a battery pack including the cylindrical battery cell, and an automobile.

[0014] However, the technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0015] According to one aspect of the present invention, a current collector plate for electrically connecting an electrode assembly housed inside a cylindrical battery cell is provided, comprising a peripheral portion defining the periphery, a central portion separated from the peripheral portion and coupled with the electrode assembly, and a connecting portion connecting the peripheral portion and the central portion, wherein the width of the connecting portion is formed to vary.

[0016] In one embodiment, the peripheral portion may be in the form of a rim in which at least a part of the inner region is open.

[0017] In one embodiment, the connecting portion includes a first portion connected to the central part and a second portion connected to the peripheral part, 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 between the first and second parts may be formed at an angle.

[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 with respect to each other.

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

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

[0022] In one embodiment, the first connecting portion is formed inclined to extend from the first portion toward the central part and can be connected to the second portion.

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

[0024] In one embodiment, the first part and the second part can be connected perpendicularly to each other.

[0025] In one embodiment, the end of the second part is located outside the end of the first part, the end of the second part and the end of the first part are located at the same distance from the central part, and the first connecting part can connect the end of the first part and the end of the second part.

[0026] In one embodiment, the second connecting part between the second part and the peripheral part can be formed to be inclined.

[0027] In one embodiment, the second connecting part includes a third inclined part on one side and a fourth inclined part on the other side, and the third inclined part and the fourth inclined part can be formed symmetrically with respect to each other.

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

[0029] In addition, according to another aspect of the present invention, a cylindrical battery cell including at least one of the above-described current collector plates is provided, a battery pack including at least one of the above-described cylindrical battery cells is provided, and further, an automobile including at least one of the above-described cylindrical battery cells can be provided.

Advantages of the Invention

[0030] According to one aspect of the present invention, there is an effect that the connecting part breaks when a short-circuit current is applied without increasing the internal resistance of the battery cell.

[0031] Also, when a short-circuit current is applied, the flow of current is interrupted by the breakage of the connecting part of the current collector plate, and there is an effect of preventing the ignition of the battery cell.

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

Brief Description of the Drawings

[0033] [Figure 1] It is a diagram showing a current collector plate according to an embodiment of the present invention. [Figure 2] This is an enlarged view of section A in Figure 1. [Figure 3] This figure shows a current collector plate according to a modified embodiment of Figure 1. [Figure 4] This is an enlarged view of section B in Figure 3. [Figure 5] This figure shows a current collector plate according to another modified embodiment of Figure 1. [Figure 6] This is an enlarged view of section C in Figure 5. [Figure 7] This diagram shows the test conditions for the current collector plate in Figure 1. [Figure 8] Figures 8(a) to 8(c) are graphs showing the test results under the test conditions shown in Figure 7. [Figure 9] This figure shows how fusing occurred during a test of the current collector plate according to the embodiment shown in Figure 1. [Figure 10] This figure shows a current collector plate according to comparative examples of each embodiment of the present invention. [Figure 11] Figure 10 shows the test conditions for the current collector plate. [Figure 12] Figures 12(a) to (c) are graphs showing the test results under the test conditions in Figure 11. [Figure 13] This is a schematic cross-sectional view of a cylindrical battery cell including a current collector plate according to each embodiment of the present invention. [Figure 14] This figure schematically shows the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention. [Figure 15] This is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention. [Modes for carrying out the invention]

[0034] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concepts of terms in order to best describe the invention. Accordingly, it should be understood that the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entirety of the technical idea of ​​the present invention, and that there may be a variety of equivalents and modifications that can be substituted therein at the time of this application.

[0035] The size of each component or specific part of a component in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity and ease of explanation. Therefore, the size of each component may not fully reflect its actual size. Specific descriptions of known functions or configurations related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention.

[0036] As used herein, the terms “joining” or “connecting” include not only cases where one member is directly joined or directly connected to another member, but also cases where one member is indirectly joined or indirectly connected to another member via a connecting member.

[0037] Figure 1 shows a current collector plate according to one embodiment of the present invention, and Figure 2 is an enlarged view of portion A in Figure 1.

[0038] A current collector plate 10 according to one embodiment of the present invention is configured to electrically connect an electrode assembly 21 (see Figure 13) housed inside a cylindrical battery cell 20 (see Figure 13). A detailed description of the cylindrical battery cell 20 will be given later. The current collector plate 10 according to an embodiment of the present invention can be used as the positive electrode current collector plate 23 (see Figure 13) of the cylindrical battery cell 20.

[0039] Referring to Figure 1, the current collector plate 10 according to one embodiment of the present invention includes a peripheral portion 100, a central portion 200, and a connecting portion 300. The current collector plate 10 is configured to electrically connect the electrode assembly 21 housed inside the cylindrical battery cell 20.

[0040] The peripheral portion 100 defines the periphery and may have a substantially rim shape with at least a portion of the inner region open, forming an internal space. Figure 1 shows a case where the peripheral portion 100 has a substantially circular rim shape, but the shape of the peripheral portion 100 is not limited to this. The peripheral portion 100 may have a substantially square rim shape, a hexagonal rim shape, an octagonal rim shape, or other shapes, different from those shown. The peripheral portion 100 may be connected to the connecting portion 300.

[0041] The central part 200 is located inside the peripheral part 100 and is separated from the peripheral part 100. For example, the central part 200 may, but is not limited to, be located at the exact center of the inner space of the peripheral part 100. The central part 200 is connected to the connecting part 300, and the connecting part 300 connects it to the peripheral part 100. The central part 200 is then connected to the electrode assembly 21 of the cylindrical battery cell 20. However, it is not only the central part 200 that is connected to the electrode assembly 21; the peripheral part 100 and the connecting part 300 may also be connected to the electrode assembly 21. The central part 200 may be positioned in a location corresponding to the central hole of the electrode assembly 21.

[0042] The connecting portion 300 connects the peripheral portion 100 and the central portion 200. Multiple connecting portions 300 may be provided, and the multiple connecting portions 300 may be spaced apart from each other. In Figure 1, four connecting portions 300 are provided, but the number of connecting portions 300 is not limited to this. Furthermore, the multiple connecting portions 300 may be arranged at equal intervals from each other, but this is not limited to this.

[0043] Referring to Figures 1 and 2, the connecting portion 300 may be formed to have a varying width. That is, the connecting portion 300 connects the peripheral portion 100 and the central portion 200, and the width of the connecting portion 300 changes as you move from the peripheral portion 100 towards the central portion 200, or from the central portion 200 towards the peripheral portion 100.

[0044] The connecting portion 300 may include a first portion 310 connected to the central portion 200 and a second portion 320 connected to the peripheral portion 100. Referring to Figures 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 towards the second portion 320.

[0045] Furthermore, the first connecting portion 330 between the first part 310 and the second part 320 may be formed at an angle. That is, it is connected at an angle from the first part 310 toward the second part 320.

[0046] Referring to Figure 2, the first connecting portion 330 includes 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 Figure 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. With such a structure, the first inclined portion 331 and the second inclined portion 332 can be formed symmetrically.

[0047] Referring to Figure 2, the first connecting portion 330 is formed inclined to extend from the first portion 310 toward the second portion 320 and can be connected to the second portion 320. For example, the end 321 of the second portion 320 is located outside the end 311 of the first portion 310 and further from the center 200 than the end 311 of the first portion 310. The first connecting portion 330 can then be configured to connect the end 311 of the first portion 310 toward the second portion 320.

[0048] Figure 3 shows a current collector plate according to a modified embodiment of Figure 1, and Figure 4 is an enlarged view of part B in Figure 3.

[0049] Referring to Figures 3 and 4, the end 321 of the second part 320 is located further out than the end 311 of the first part 310, and the end 321 of the second part 320 and the end 311 of the first part 310 are located at the same distance from the center 200, and the first connecting part 330 may be configured to connect the end 311 of the first part 310 and the end 321 of the second part 320. In this way, the first part 310 and the second part 320 can be connected perpendicularly to each other.

[0050] Figure 5 shows a current collector plate according to another modified embodiment of Figure 1, and Figure 6 is an enlarged view of portion C in Figure 5.

[0051] Referring to Figures 5 and 6, the first connecting portion 330 is formed inclined to extend from the first portion 310 toward the center 200 and can be connected to the second portion 320. For example, the end 321 of the second portion 320 is located outside the end 311 of the first portion 310 and closer to the center 200 than 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 toward the center 200 from the end 311 of the first portion 310.

[0052] Here, the modified embodiments in Figure 3 and Figure 5 also provide the same or similar effects as the embodiment in Figure 1.

[0053] Referring to Figures 2, 4, and 6, the second connecting portion 340 between the second part 320 and the peripheral portion 100 may also be formed at an angle. That is, it is connected at an angle from the second part 320 toward the peripheral portion 100.

[0054] The second connecting portion 340 may include 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 may be configured to have the same inclination toward opposite directions.

[0055] That is, referring to Figure 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 it does not necessarily have to be parallel, and the fourth inclined portion 342 may be formed parallel to the Y direction, but it does not necessarily have to be parallel.

[0056] With 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.

[0057] However, the first inclined portion 331 and the third inclined portion 341 may be parallel, but they do not have to be parallel, and the second inclined portion 332 and the fourth inclined portion 342 may be parallel to each other, but they do not have to be parallel.

[0058] In this way, when the width of the connecting portion 300 of the current collector plate 10 is formed to change, the effect is achieved in which the connecting portion 300 breaks when a short-circuit current is applied without increasing the internal resistance of the battery cell.

[0059] In other words, because the internal resistance of the battery cell does not increase due to the aforementioned structure, the performance of the cylindrical battery cell 20 is maintained, and when a short-circuit current is applied, the connecting part 300 breaks and performs a fusing function, so the flow of current is interrupted and ignition does not occur.

[0060] Figure 7 shows the test conditions for the current collector plate in Figure 1, Figures 8(a) to 8(c) are graphs showing the test results under the test conditions in Figure 7, and Figure 9 shows how fusing occurred during the current collector plate test according to the embodiment in Figure 1.

[0061] Referring to Figure 7, three tests #1, #2, and #3 were performed under the same conditions. The test conditions were an externally applied resistance of 5.08 mΩ. The internal resistance of the battery cells in each of the three tests was 1.44 mΩ, 1.45 mΩ, and 1.42 mΩ. The maximum current in each of the three tests was 749 A, 764 A, and 722 A. At the start of the shutdown, the temperature of the battery cells in each of the three tests was 46.7°C, 42.3°C, and 45.3°C.

[0062] In all three tests, the internal resistance of the battery cells did not exceed 1.5 mΩ.

[0063] Referring to Figure 7, the fusing onset times in each of the three tests were 16.1 seconds, 16.5 seconds, and 17.2 seconds, and none of the three exceeded 20 seconds. In relation to this, in Figure 8(a), the thick solid line a1 on the left represents voltage, and the thick dotted line a2 on the left represents current (the same applies to Figures 8(b) and (c)). Referring to Figures 8(a) to (c), in (a), it can be seen that fusing occurred at 16.1 seconds and the voltage and current dropped sharply, in (b), it can be seen that fusing occurred at 16.5 seconds and the voltage and current dropped sharply, and in (c), it can be seen that fusing occurred at 17.2 seconds and the voltage and current dropped sharply.

[0064] In other words, in the case of one embodiment of the present invention, it can be confirmed by experiment that it is possible to prevent overcurrent from flowing because it has an appropriate fusing time.

[0065] Referring further to Figure 7, the external short-circuit results were "pass" in all three tests. Here, a passing 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 that fusing, i.e., the connection part 300 does not break and the battery cell does not ignite or explode, within a preset time (e.g., 20 seconds). Referring to Figure 9, fusing 360 occurred near the connection point between the central part 200 and the first part 310.

[0066] On the other hand, in Figure 8(a), the thin dotted line a3 represents the temperature of the positive electrode tab of the cylindrical battery cell 20, the thin solid line a4 represents the temperature of the negative electrode tab of the cylindrical battery cell 20, the dashed line a5 represents the temperature of the battery casing 22 of the cylindrical battery cell 20 (see Figure 13), and the dashed line a6 represents the temperature of the vent portion of the cylindrical battery cell 20 (the same applies to Figures 8(b) and (c)).

[0067] Referring to Figures 8(a) to 8(c), the temperature of the positive electrode tab rises partially and then decreases (see a3), while the temperature of the negative electrode tab, the battery can 22, and the vent section remain within an appropriate range. In other words, experiments have confirmed that with the current collector plate according to one embodiment of the present invention, excessive temperature rise does not occur, and as a result, the cylindrical battery cell 20 does not ignite.

[0068] As a result, the current collector plate according to one embodiment of the present invention does not increase the internal resistance of the battery cell, and when a short-circuit current is applied, the connection breaks, allowing for smooth fusing. The current flow is interrupted by the breakage of the connection of the current collector plate when a short-circuit current is applied, thereby preventing the battery cell from catching fire.

[0069] Figure 10 shows a current collector plate according to comparative examples of each embodiment of the present invention, Figure 11 shows the test conditions for the current collector plate in Figure 10, and Figures 12(a) to (c) are graphs showing the test results under the test conditions in Figure 11.

[0070] Referring to Figure 10, a current collector plate 11 is shown in which the width of the connecting portion 400 does not change.

[0071] Referring to Figure 11, three tests #1, #2, and #3 were performed under the same conditions as in Figure 7. The test conditions were as follows: the external applied resistance for each of the three tests was 5.08 mΩ, 5.23 mΩ, and 5.3 mΩ. The internal resistance of the battery cells for each of the three tests was 1.38 mΩ, 1.42 mΩ, and 1.37 mΩ. The maximum current for each of the three tests was 764 A, 732 A, and 754 A. At the start of the shutdown, the temperature of the battery cells for each of the three tests was 89.6°C, 81.9°C, and 79.2°C.

[0072] In all three tests, the internal resistance of the battery cells never exceeded 1.5 mΩ.

[0073] Here, in Figure 12(a), the thick solid line a7 on the left represents voltage, and the thick dotted line a8 on the left represents current (the same applies to Figures 12(b) and (c)). Referring to Figures 12(a) to (c), the fusing start times for each of the three tests were 45.3 seconds, 53.5 seconds, and 44.8 seconds, and all three exceeded 20 seconds.

[0074] Specifically, referring further to Figure 11, the external short-circuit results were "fail" in all three tests. Here, a failure of the external short-circuit results means that when a short-circuit current is applied to the battery cell, fusing does not occur within a predetermined time (for example, 20 seconds), meaning that the connection part 300 does not break, and thus the battery cell may ignite or explode.

[0075] In Figure 12(a), the thin dotted line a9 represents the temperature of the positive electrode tab of the cylindrical battery cell 20, the thin solid line a10 represents the temperature of the negative electrode tab of the cylindrical battery cell 20, the dashed line a11 represents the temperature of the battery casing 22 of the cylindrical battery cell 20 (see Figure 13), and the dashed line a12 represents the temperature of the vent portion of the cylindrical battery cell 20 (the same applies to Figures 12(b) and (c)).

[0076] Referring to Figures 12(a) to (c), the temperature of the vent portion of the cylindrical battery cell 20 rises rapidly (see a12), and the temperature of the battery casing 22 of the cylindrical battery cell 20 also rises (see a11). This means that ignition occurred inside the cylindrical battery cell 20 and flames were expelled to the outside through the vent portion. In other words, the experiment shows that the cylindrical battery cell easily ignited with the conventional current collector plate.

[0077] In other words, in the case of the current collector plate 10 according to one embodiment of the present invention (see Figure 1), as shown in Figures 7 to 9, the internal resistance of the cylindrical battery cell 20 did not exceed a preset range, and the connecting portion 300 broke within a preset time, thereby preventing the cylindrical battery cell 20 from igniting or exploding. However, in the case of the current collector plate 11 of the comparative example (see Figure 10), as shown in Figures 11 and 12, although the internal resistance of the battery cell did not exceed a preset range, the connecting portion 400 did not break within a preset time, and the battery cell ignited.

[0078] Therefore, the current collector plate 10 according to one embodiment of the present invention can break the connecting portion 300 when a short-circuit current is applied without increasing the internal resistance of the cylindrical battery cell 20, and the current flow is interrupted by the breakage of the connecting portion 300 of the current collector plate 10, thereby preventing the cylindrical battery cell 20 from catching fire.

[0079] 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 invention.

[0080] The cylindrical battery cell 20 includes an electrode assembly 21, a battery casing 22, a positive electrode current collector plate 23, cell terminals 24, and a negative electrode current collector plate 25. Here, the positive electrode current collector plate 23 in Figure 13 may be the current collector plate 10 according to the embodiment of the present invention described above.

[0081] The electrode assembly 21 has a structure in which a positive electrode plate, a negative electrode plate, and a separation membrane interposed between the positive and negative electrode plates are wound in one direction. A central hole is formed in the center of the electrode assembly 21, and it can be formed in the shape of a jelly roll.

[0082] For example, the electrode assembly 21 can be manufactured by winding up a laminate formed by stacking a negative electrode plate, a separator membrane, a positive electrode plate, and a separator membrane at least once in that order. Here, the positive electrode plate and the negative electrode plate may be in sheet form.

[0083] That is, the electrode assembly 21 to be applied to this embodiment may be a winding type electrode assembly 21. In this case, the outer circumferential surface of the electrode assembly 21 may be further provided with a separation film for insulation from the battery can 22. That is, the electrode assembly 21 may have any known winding structure in the relevant art without limitation.

[0084] The positive electrode plate has a positive electrode active material coated on one or both sides, and a first uncoated area where the positive electrode active material is not coated may be formed at the edge of the positive electrode plate. Figure 13 shows a positive electrode plate with the first uncoated area formed thereon, but a cylindrical battery cell 20 according to one embodiment of the present invention includes embodiments relating to a positive electrode plate in which the first uncoated area is not formed. However, for the sake of explanation, the following description will focus on the case in which the first uncoated area is formed on the positive electrode plate. The first uncoated area can be exposed to the outside of the separator membrane by forming multiple winding turns with respect to the center of the electrode assembly 21 and can be used as an electrode tab.

[0085] The negative electrode plate has a negative electrode active material coated on one or both sides, and a second uncoated area where the negative electrode active material is not coated may be formed at the end of the negative electrode plate. Figure 13 shows a negative electrode plate with a second uncoated area formed thereon, but a cylindrical battery cell 20 according to one embodiment of the present invention includes embodiments relating to a negative electrode plate in which the second uncoated area is not formed. However, for the sake of explanation, the following description will focus on the case in which the negative electrode plate has a second uncoated area formed thereon. The second uncoated area can be exposed to the outside of the separator membrane by forming multiple winding turns with respect to the center of the electrode assembly 21 and can be used as an electrode tab.

[0086] That is, at least one of the positive electrode plate and the negative electrode plate may each include an uncoated portion at the long edge in the winding direction where the active material is not applied. The first uncoated portion and the second uncoated portion may be configured to face in opposite directions.

[0087] Here, the positive electrode active material applied to the positive electrode plate and the negative electrode active material applied to the negative electrode plate can be any active material known in this industry, without any limitations.

[0088] The separation membrane can be made from porous polymer films, such as ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, or ethylene / methacrylate copolymers, either alone or in a laminated configuration.

[0089] As another example, the separation membrane may be made of a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0090] At least one surface of the separation membrane may include a coating layer of inorganic particles. Furthermore, the separation membrane itself may consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound to a binder such that interstitial volumes exist between adjacent particles.

[0091] Furthermore, the central hole of the electrode assembly 21 can be used for welding the cell terminal 24 (positive electrode terminal) and the positive electrode current collector plate 23. That is, the electrode assembly 21 can be configured to weld the cell terminal 24 and the positive electrode current collector plate 23 by irradiating them with a laser from the central hole.

[0092] Referring to Figure 13, the electrode assembly 21 is housed in the battery can 22. Through holes may be formed in the battery can 22. For example, the battery can 22 may be formed in a cylindrical shape, with the electrode assembly 21 housed inside the battery can 22, and may be electrically connected to the negative electrode plate of the electrode assembly 21. As a result, the battery can 22 may have the same polarity as the negative electrode plate, i.e., be the negative electrode.

[0093] 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 predetermined size is formed between the battery can 22 and the positive electrode current collector plate 23, and an insulator may be interposed in the gap.

[0094] If the size of the electrode assembly 21 is increased while the size of the battery can 22 is determined by the standard, the total capacity of the battery cells will increase, but the distance between the battery can 22 and the electrode assembly 21 will decrease.

[0095] In other words, if the size of the electrode assembly 21 is increased to increase the total capacity of the battery cell, the distance between the battery can 22 and the electrode assembly 21 decreases. Therefore, in order to increase the capacity of the battery cell, an insulator should be interposed in the reduced distance between the battery can 22 and the electrode assembly 21. For this reason, it is desirable that the thickness of the insulator be as thin as possible.

[0096] The battery can 22 may have a closed section and an open section formed at opposite positions to each other. For example, an open section may be formed at the bottom of the battery can 22. The electrode assembly 21 is housed in the battery can 22 through the open section at the bottom, and the electrolyte is also injected through the open section at the bottom of the battery can 22.

[0097] In other words, the battery can 22 is a substantially cylindrical housing with an open section at the bottom, and can be made of a conductive material such as metal. The material of the battery can 22 can be a conductive metal, such as aluminum, steel, or stainless steel, but is not limited to these.

[0098] Furthermore, referring to Figure 13, a closed section may be formed on the upper part of the battery can 22. The closed section may be partially formed on the opposite side of the open section. Through holes are formed in the closed section, and as shown in Figure 13, the cell terminals 24 are connected to the through holes and electrically connected to the positive electrode current collector plate 23 through the through holes. Referring to Figure 13, an insulator may be interposed between the battery can 22 on the closed section side and the positive electrode current collector plate 23.

[0099] The positive electrode current collector plate 23 is electrically connected to the positive electrode plate. For example, referring to Figure 13, the positive electrode current collector plate 23 is connected to the positive electrode plate at the top of the electrode assembly 21.

[0100] The positive electrode 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 electrode current collector plate 23 can be connected to the upper part of a coupling surface formed by bending the end of the first uncoated portion parallel to the positive electrode current collector plate 23. The bending direction of the first uncoated portion may be, for example, towards the winding center 200 of the electrode assembly 21.

[0101] When the first uncoated portion has this folded shape, the space occupied by the first uncoated portion is reduced, which can improve energy density. In addition, by increasing the bonding area between the first uncoated portion and the positive electrode current collector plate 23, it is possible to improve bonding strength and reduce resistance.

[0102] The 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 electrode current collector plate 23 through the through-hole. The cell terminal 24 is then electrically connected to the positive electrode plate of the electrode assembly 21 via the positive electrode current collector plate 23, thereby having positive polarity.

[0103] In other words, the cell terminal 24 can function as a positive terminal. The battery can 22 is electrically connected to the negative electrode plate of the electrode assembly 21, as described above, and thus can have negative polarity.

[0104] The negative electrode current collector plate 25 is connected to the second uncoated portion of the electrode assembly 21. The negative electrode current collector plate 25 is coupled to the lower part of the electrode assembly 21. The negative electrode 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.

[0105] The negative electrode current collector plate 25 can be electrically connected to the battery can 22. To achieve this, at least a portion of the edge of the negative electrode current collector plate 25 can be interposed and fixed between the inner surface of the battery can 22 and the sealing gasket.

[0106] In one embodiment, at least a portion of the edge of the negative electrode current collector plate 25 can be fixed to the beading portion 27 formed at the lower end of the battery can 22 by welding, while being supported by the lower end surface of the beading portion 27. In a modified embodiment, at least a portion of the edge of the negative electrode current collector plate 25 can be directly welded to the inner wall surface of the battery can 22.

[0107] Furthermore, at least a portion of the remaining part of the negative electrode current collector plate 25, excluding the joint portion of the beading portion 27, can be joined to the bent surface of the second uncoated portion by welding, for example, laser welding.

[0108] Furthermore, at least a portion of the edge of the negative electrode current collector plate 25 can be electrically coupled to the upper and lower surfaces of the beading portion 27 that are adjacent to the crimping portion 28.

[0109] Referring to Figure 13, the cap plate 26 is configured to seal the opening formed at the lower end of the battery can 22. The cap plate 26 may be made of a metal material, for example, to ensure rigidity.

[0110] Furthermore, the cap plate 26 can be provided separately from the electrode assembly 21 and in a non-polar manner. That is, even if the cap plate 26 is made of a conductive metal material, it can be non-polar.

[0111] The fact that the cap plate 26 has no polarity means that the cap plate 26 is electrically insulated from the battery can 22 and the cell terminals 24. Thus, the cap plate 26 does not need to have polarity, and its material does not necessarily need to be a conductive metal.

[0112] The cap plate 26 may be mounted and supported on a beading portion 27 formed on the battery can 22. The cap plate 26 is also fixed by a crimping portion 28, which will be described later. A sealing gasket may be interposed between the cap plate 26 and the crimping portion 28 of the battery can 22 to ensure the airtightness of the battery can 22. That is, the sealing gasket may be provided so as to be interposed between the edge of the cap plate 26 and the open portion of the battery can 22.

[0113] A beading section 27 and a crimping section 28 may be formed at the bottom of the battery can 22.

[0114] The beading portion 27 is formed when the outer surface of the battery can 22 is press-fitted inward in the region adjacent to the opening of the battery can 22.

[0115] The beading portion 27 supports the electrode assembly 21, which has a size approximately corresponding to the width of the battery can 22, to prevent it from coming out of 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 circumferential surface of the sealing gasket.

[0116] The crimping portion 28 extends inward from the battery can 22 and is bent to surround 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 state in which the battery can 22 is positioned. For example, if the battery can 22 is positioned with the cell terminals 24 at the top as shown in Figure 13, the crimping portion 28 is formed at the bottom of the battery can 22, based on Figure 13. And, as shown in Figure 13, the crimping portion 28 is formed below 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 to this.

[0117] The present invention does not exclude cases 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, if the battery can 22 does not have at least one of the beading portion 27 and the crimping portion 28, fixing the electrode assembly 21, fixing the cap plate 26, or sealing the battery can 22 can be achieved by at least one of the following: additional application of a component that can function as a stopper to the electrode assembly 21, additional application of a structure on which the cap plate 26 can be mounted, or welding the battery can 22 and the cap plate 26.

[0118] Based on Figure 13, the crimping portion 28 is formed at the bottom of the beading portion 27. The crimping portion 28 has a shape that extends and bends to surround the edge of the cap plate 26, which is positioned at the bottom of the beading portion 27. The cap plate 26 is fixed to the beading portion 27 by the shape of the crimping portion 28 that is bent in this way.

[0119] On the other hand, the battery can 22 of the present invention does not necessarily have to have at least one of the beading portion 27 and the crimping portion 28. In this case, the sealing gasket may be interposed between the fixing structure provided on the open side of the battery can 22 to ensure the airtightness of the battery can 22 and the cap plate 26.

[0120] For example, the crimping portion 28 may be omitted, and the cap plate 26 may be fixed to cover the opening of the battery can 22 by other fixing structures. For example, the applicant's Korean Published Patent No. 10-2019-0030016 discloses a cylindrical battery cell in which the beading portion 27 is omitted, and such a structure may be adopted in the present invention.

[0121] A vent notch 29 may be formed in the cap plate 26 so as to rupture if the internal pressure of the battery can 22 exceeds a critical value.

[0122] For example, the vent notches 29 may be formed on both sides of the cap plate 26, and on the surface of the cap plate 26, they may be formed in at least one of a continuous circular pattern, a discontinuous circular pattern, and a linear pattern. In addition, the vent notches 29 may be formed in a variety of other patterns.

[0123] The vent notch 29 is formed at the lower end of the battery can 22, based on the arrangement of the battery can 22 in Figure 13, and is designed so that when the vent notch 29 ruptures, the gas inside the battery can 22 is discharged from the lower end of the battery can 22. For example, if the battery can 22 is arranged so that the cell terminals 24 are located at the upper end, as in Figure 13, the vent notch 29 can be formed at the lower end of the battery can 22, based on Figure 13.

[0124] The vent notch 29 can be formed in the cap plate 26 as a region having a thinner thickness than the surrounding region.

[0125] Because the vent notch 29 is thinner than the surrounding area, it is more easily ruptured than the surrounding area, and when the internal pressure of the battery can 22 increases above a certain level, the vent notch 29 ruptures, allowing the gas generated inside the battery can 22 to be released.

[0126] For example, the vent notch 29 may be formed by notching one or both sides of the cap plate 26 to partially reduce the thickness of the battery can 22.

[0127] A cylindrical battery cell 20 according to one embodiment of the present invention can have a structure in which both positive and negative terminals are present at the top, with reference to Figure 13, and this makes the upper structure more complex than the lower structure.

[0128] Therefore, a vent notch 29 may be formed in the cap plate 26 that forms the lower surface of the cylindrical battery cell 20 in order to facilitate the smooth discharge of gas generated inside the battery can 22.

[0129] Thus, if the gas generated inside the battery can 22 of the cylindrical battery cell 20 is discharged downward, it may also be advantageous for the user's safety.

[0130] For example, if a cylindrical battery cell 20 is placed directly beneath the driver's seat of an electric vehicle, the gas could be discharged upwards, potentially posing a safety risk to the driver. However, if the gas is discharged downwards from the battery can 22, as in the cylindrical battery cell 20 according to one embodiment of the present invention, the aforementioned problem does not occur even if the cylindrical battery cell 20 is placed directly beneath the driver's seat of an electric vehicle.

[0131] Figure 14 is a schematic diagram showing the configuration of a battery pack including cylindrical battery cells according to each embodiment of the present invention.

[0132] Referring to Figure 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 cell 20 may include at least one current collector plate 10 according to one embodiment of the present invention as described above.

[0133] The battery pack 30 may also include a pack housing 31 for housing the cylindrical battery cells 20, and various devices for controlling the charging and discharging of the cylindrical battery cells 20, such as a BMS, current sensors, and fuses.

[0134] Figure 15 is a diagram illustrating an automobile including a battery pack according to each embodiment of the present invention.

[0135] Referring to Figure 15, an automobile 40 according to one embodiment of the present invention may include one or more cylindrical battery cells 20 or battery packs 30 according to the embodiments described above. The battery pack 30 includes cylindrical battery cells 20 according to the embodiments described above.

[0136] Here, the automobile 40 includes various types of automobiles that use electricity, such as electric vehicles or hybrid vehicles.

[0137] In this specification, terms indicating direction such as up, down, left, right, front, and back are used. However, such terms indicate relative positions and are for the sake of convenience of explanation only. It is obvious to those skilled in the art that these positions can change depending on the position of the object in question, the observer's position, and so on.

[0138] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and of course, various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims below by persons with ordinary skill in the art to which the present invention pertains. Therefore, the embodiments described above should be considered from an explanatory rather than restrictive viewpoint. That is, the true technical concept of the present invention is shown in the claims, and all differences within the equivalent scope thereto should be interpreted as being included in the present invention. [Industrial applicability]

[0139] The present invention relates to a current collector plate, a cylindrical battery cell containing the same, a battery pack containing the cylindrical battery cell, and an automobile, and is particularly applicable to the secondary battery industry. [Explanation of Symbols]

[0140] 10 Current collector plate 11 Current collector plate 20 cylindrical battery cells 21 Electrode assembly 22 Battery Cans 23 Positive electrode current collector plate 24-cell terminal 25 Negative electrode current collector plate 26 Cap Plate 27 Beading section 28 Crimping section 29 Bent Notch 30 Battery Packs 31 Pack Housing 40 Automobiles 100 Peripheral area 200 Winding center 300 Connection section 310 Part 1 311 End 320 Part 2 321 End 330 1st connection part 331 1st slope section 332 2nd slope part 340 2nd connection part 341 Third slope 342 4th slope 350 through hole 360 Fusing 400 Connection section

Claims

1. A current collector plate that electrically connects electrode assemblies housed inside a cylindrical battery cell, The peripheral part that defines the periphery, It is separated from the aforementioned peripheral portion and has a central part that connects to the electrode assembly, A current collector plate comprising a connecting portion that connects the peripheral portion and the central portion, characterized in that the width of the connecting portion is formed to vary.

2. The current collector plate according to claim 1, characterized in that the peripheral portion is in the form of a rim in which at least a part of the inner region is open.

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

4. The current collector plate according to claim 3, characterized in that the first connecting portion between the first part and the second part is formed at an inclination.

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

6. The current collector plate according to claim 4, characterized in that the first connecting portion is formed inclined to expand from the first portion toward the second portion and is connected to the second portion.

7. The end of the second part is located outside the end of the first part, and is further from the center than the end of the first part. The current collector plate according to claim 6, characterized in that 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, characterized in that the first connecting portion is formed inclined to expand from the first portion toward the central portion and is connected to the second portion.

9. The end of the second part is located outside the end of the first part, and is closer to the center than the end of the first part. The current collector plate according to claim 8, characterized in that the first connecting portion connects the end of the second portion toward the central part from the end of the first portion.

10. The current collector plate according to claim 3, characterized in that the first part and the second part are connected perpendicularly to each other by a first connecting portion.

11. The end of the second part is located outward from the end of the first part. The end of the second part and the end of the first part are located at the same distance from the center. The current collector plate according to claim 10, characterized in that the first connecting portion connects the end of the first part and the end of the second part.

12. The current collector plate according to claim 3, characterized in that the second connecting portion between the second part and the peripheral portion is formed at an inclination.

13. The current collector plate according to claim 12, 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 with respect to each other.

14. The current collector plate according to claim 13, 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. A battery pack comprising at least one cylindrical battery cell as described in claim 15.

17. An automobile comprising at least one cylindrical battery cell as described in claim 15.

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