Cylindrical battery, and battery pack and vehicle including same

Abstract

The present invention provides a cylindrical battery structured to incur less deformation due to crimping pressure when undergoing crimping during battery manufacturing. The cylindrical battery according to one aspect of the invention comprises: an electrode assembly including a first electrode and a second electrode; a battery housing for accommodating the electrode assembly through an opening part formed in the top thereof; and a top cap which covers the opening part, and which includes an edge area, a central area positioned relatively more inward than the edge area, and a bent area that is positioned between the edge area and the central area and that has a first bent part having a downwardly-bent protruding shape.

Description

Cylindrical batteries, and battery packs and vehicles containing them

[0001] The present invention relates to a cylindrical battery, and a battery pack and a vehicle including the same, and more particularly, to a cylindrical battery having a structure that is less deformed by crimping pressure during a crimping process during a battery manufacturing process, and a battery pack and a vehicle including the same.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0059395, filed on May 8, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated herein by reference.

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

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

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells is approximately 2.5 V to 4.5 V. Therefore, if a higher output voltage is required, multiple batteries are connected in series to form a battery pack. Furthermore, depending on the required charge / discharge capacity of the battery pack, multiple batteries are connected in parallel to form a battery pack. Therefore, the number of batteries included in a battery pack and the electrical connection type can be set in various ways depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, cylindrical, prismatic, and pouch-shaped secondary battery cells are known. Cylindrical batteries are formed by interposing an insulator separator between the positive and negative electrodes, winding the separator to form a jelly-roll-shaped electrode assembly, which is then inserted into the battery housing along with the electrolyte. The upper end of the battery housing is then crimped to wrap around the edge of the top cap. This crimping process forms a crimping portion that secures the top cap to the top of the battery.

[0007] During this crimping process, a large force is applied to the battery housing and top cap, resulting in a large pressure applied toward the center (side force) and downwards of the top cap. Consequently, there was a problem of deformation of the top cap due to this pressure.

[0008]

[0009] The present invention was created in consideration of the above-described problems, and its primary purpose is to minimize deformation caused by crimping pressure during the crimping process.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011]

[0012] A cylindrical battery according to one embodiment of the present invention may include an electrode assembly having a first electrode and a second electrode, a battery housing accommodating the electrode assembly through an opening formed at an upper end, and a top cap configured to cover the opening, the top cap including a bending region having an edge region, a center region located relatively further inward compared to the edge region, and a first bending region located between the edge region and the center region and having a shape that is convexly bent downward.

[0013] The above central region may be positioned higher than the above edge region.

[0014] The top of the above battery housing may be positioned higher than the top of the above central region.

[0015] The lower end of the first bending portion may be positioned lower than the lower end of the central region and the lower end of the edge region.

[0016] The above-mentioned bending region may include a second bending portion having a shape that is convexly bent upward.

[0017] The above central region may include a second folded portion having a shape that is convexly bent upward.

[0018] The upper end of the second bending portion may be at the same height as the upper end of the battery housing.

[0019] The top cap may have a venting portion configured to be more vulnerable compared to the surrounding area.

[0020] The above venting portion may have a thinner thickness compared to the surrounding area.

[0021] The above venting portion may be provided in the central region.

[0022] The above top cap may be configured to have no polarity.

[0023] The cylindrical battery may include a first current collector positioned between the electrode assembly and the top cap, the first electrode coupling portion electrically coupled to the first electrode, and a housing coupling portion coupled on an inner surface of the battery housing.

[0024] The above first bending portion may be located on the housing joint portion.

[0025] A battery pack according to the present invention may include a cylindrical battery according to the present invention.

[0026] A vehicle according to the present invention may include a battery pack according to the present invention.

[0027]

[0028] According to one aspect of the present invention, even when a large pressure is applied toward the center of the top cap during the crimping process, the pressure can be cushioned through the bending portion. When compressive pressure is applied toward the center and lower portion of the top cap, only slight deformation occurs in the bending portion due to the already bent bending portion, while no deformation occurs or is minimized in the edge and center regions, which have a roughly flat shape. Therefore, even during the crimping process, deformation of the top cap is minimized, thereby improving the stability and durability of the battery.

[0029] According to another aspect of the present invention, the central region is configured to capture gas generated within the battery, compared to a case where the central region is positioned lower than the edge regions. Therefore, the central region is better able to withstand gas pressure. If a problem occurs in the battery and the internal pressure of the battery housing increases to a certain level, the central region may rupture or the crimping portion may become loose, allowing gas to escape.

[0030] According to another aspect of the present invention, when the opening is positioned at the bottom, even if the bottom of the battery housing touches the ground or the bottom surface of the housing for a module or pack configuration, the top cap does not touch the ground or the bottom surface of the housing for a module or pack configuration. Therefore, the risk of scratching or damage to the top cap can be reduced. Furthermore, this configuration can prevent the pressure required to rupture the venting portion formed in the top cap from differing from the design value.

[0031] According to another aspect of the present invention, the total height of the top cap can be reduced. Accordingly, the height of the electrode assembly can be increased by the amount of height reduced by the top cap, thereby improving energy density.

[0032] According to another aspect of the present invention, the movement of the current collector in the Z-axis direction can be controlled. Accordingly, the current collector can be stably attached to the battery housing.

[0033]

[0034] Figure 1 is a drawing showing a cross-section of a cylindrical battery according to the present invention.

[0035] Figure 2 is a drawing showing the appearance of a cylindrical battery according to the present invention.

[0036] Figure 3 is a drawing showing a cylindrical battery according to the present invention before the crimping process.

[0037] FIG. 4 is a partially cutaway view of a top cap included in a cylindrical battery according to the present invention.

[0038] FIGS. 5 to 10 are drawings showing cross-sections of a top cap included in a cylindrical battery according to the present invention.

[0039] Figure 11 is a drawing showing a cross-section of a cylindrical battery according to the present invention.

[0040] Figure 12 is a drawing showing a battery pack according to the present invention.

[0041] Figure 13 is a drawing showing a vehicle according to the present invention.

[0042]

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be construed as being limited to the matters described in the drawings. Like reference numerals designate like components. Furthermore, in the drawings, the thicknesses, ratios, and dimensions of components may be exaggerated for the purpose of effectively explaining the technical contents.

[0044] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0045] Although terms indicating directions such as up, down, left, right, front, and back are used in this specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0046] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0047] Figure 1 is a cross-sectional view of a cylindrical battery according to the present invention. Figure 2 is a view showing the exterior of a cylindrical battery according to the present invention. Figure 3 is a view showing a cylindrical battery according to the present invention before the crimping process.

[0048] Referring to FIGS. 1 to 3, a cylindrical battery (10) according to the present invention may include an electrode assembly (100), a battery housing (200), and a top cap (300).

[0049] An electrode assembly (100) may include a first electrode tab (110) and a second electrode tab (120). The electrode assembly (100) includes a first electrode having a first polarity, a second electrode having a second polarity, and a separator interposed between the first electrode and the second electrode. The first electrode is a cathode or an anode, and the second electrode corresponds to an electrode having a polarity opposite to that of the first electrode. The electrode assembly (100) may be manufactured by winding a laminate formed by sequentially stacking the first electrode, the separator, the second electrode, and the separator at least once. That is, the electrode assembly (100) applied to the present invention may be a jelly-roll type electrode assembly (100). The first electrode may be an anode or a cathode, and the second electrode may be an electrode having a polarity opposite to that of the first electrode.

[0050] Such a jelly-roll type electrode assembly (100) may have a winding center hole (H1) formed approximately at the center thereof and extending along the height direction (parallel to the Z axis).

[0051] The first electrode may include a first electrode plate and a first electrode active material layer formed by applying a first electrode active material on at least one surface of the first electrode plate. The second electrode may include a second electrode plate and a second active material layer formed by applying a second electrode active material on at least one surface of the second electrode plate. The first electrode may include a first uncoated portion on which a positive electrode active material or a negative electrode active material is not applied to the electrode plate. The second electrode may include a second uncoated portion on which a positive electrode active material or a negative electrode active material is not applied to the electrode plate. For example, the first uncoated portion may be provided at an upper portion of the electrode assembly (100), and the second uncoated portion may be provided at a lower portion of the electrode assembly (100). At least a portion of the first uncoated portion may function as a first electrode tab (110), and at least a portion of the second uncoated portion may function as a second electrode tab (120). Meanwhile, in the present invention, the electrode tab (110, 120) is not limited to being at least a part of the non-conductive portion. That is, the electrode tab (110, 120) may be provided separately and coupled to the non-conductive portion.

[0052] The battery housing (200) can accommodate the electrode assembly (100) through an opening (O) formed at the top. The battery housing (200) is a generally cylindrical container having an opening (O) formed at the top, and may be made of a conductive metal material. The side surface of the battery housing (200) and the lower surface (the surface located in the negative Z-axis direction) located opposite the opening (O) may be formed integrally. That is, the upper surface of the battery housing (200) in the height direction may be open, and the lower surface may be closed. The lower surface of the battery housing (200) may have a generally flat shape. The battery housing (200) may also accommodate an electrolyte through the opening (O). However, the battery housing (200) of the present invention is not limited to this shape.

[0053] The battery housing (200) may include an inner portion (210) and a crimping portion (220).

[0054] The inner portion (210) is formed at an end adjacent to the opening (O) and can be pressed inward. The inner portion (210) can have a shape in which the outer circumference of the battery housing (200) is pressed to a predetermined depth. The inner portion (210) can be formed on the upper portion of the electrode assembly (100). The inner diameter of the battery housing (200) in the area where the inner portion (210) is formed can be formed to be smaller than the diameter of the electrode assembly (100).

[0055] The crimping portion (220) may be formed on the upper portion of the inner portion (210). The crimping portion (220) may have an extended and bent shape to surround the edge area (S1) of the top cap (300) described later. The top cap (300) may be fixed on the inner portion (210) by the shape of the crimping portion (220).

[0056] Fig. 4 is a partially cutaway view of a top cap included in a cylindrical battery according to the present invention. Figs. 5 to 10 are cross-sectional views of a top cap included in a cylindrical battery according to the present invention.

[0057] Referring to FIG. 5 together with FIGS. 1 to 3, the top cap (300) may be configured to cover the opening (O). The top cap (300) may include an edge region (S1), a center region (S3), and a fold region (S2). The edge region (S1) may be located at the outermost side of the top cap (300). The edge region (S1) may be surrounded by the battery housing (200) during the crimping process. The center region (S3) may be located relatively further inward compared to the edge region (S1). The fold region (S2) may be located between the center region (S3) and the edge region (S1). The fold region (S2) may have a first fold portion (320) that is bent convexly downward. However, as shown in FIG. 6, the first fold portion (320) may also have a shape that is bent convexly upward.

[0058] The top cap (300) may be configured to be non-polarized. That is, in the present invention, the top cap (300) may be configured not to be electrically connected to the electrode assembly (100). The top cap (300) may be formed of, for example, a metal material to ensure rigidity, but even in this case, it may not be polarized. The top cap (300) may include an insulating material. However, the present invention is not limited to the top cap (300) being non-polarized, and it may have the same polarity as the battery housing (200).

[0059] According to this configuration of the present invention, even if a large pressure is applied toward the center of the top cap (300) during the crimping process described above, the pressure can be buffered through the first folded portion (320). When a compressive pressure is applied toward the center and lower portion of the top cap (300), only a slight deformation occurs in the first folded portion (320) due to the first folded portion (320) that has already been folded, and no deformation occurs or the deformation can be minimized in the edge region (S1) and the center region (S3) having a substantially flat shape. Therefore, even if the crimping process is performed, deformation of the top cap (300) is small, so that the stability and durability of the battery can be improved.

[0060] Referring to FIGS. 4 to 6, the central region (S3) may be positioned higher than the edge region (S1).

[0061] According to this configuration of the present invention, compared to a case where the central region (S3) is positioned lower than the edge region (S1), the central region (S3) is configured to capture gas generated within the battery. Therefore, the central region (S3) can better withstand pressure from the gas. If a problem occurs in the battery and the internal pressure of the battery housing (200) increases to a certain level, the central region (S3) may be broken or the crimping portion (220) may be released, causing gas to be discharged.

[0062] Referring to FIGS. 4 to 6 together with FIG. 1, the upper portion of the battery housing (200) may be positioned higher than the upper portion of the central region (S3).

[0063] According to this configuration of the present invention, when the opening (O) is located at the bottom, even if the bottom of the battery housing (200) touches the ground or the bottom surface of the housing for the module or pack configuration, the top cap (300) does not touch the ground or the bottom surface of the housing for the module or pack configuration. Therefore, the risk of scratches or damage to the top cap (300) can be reduced. In addition, even when the venting portion (310) described below is provided in the top cap (300), the venting portion (310) does not touch the ground or the bottom surface of the housing for the module or pack configuration, so that the pressure required for the rupture of the venting portion (310) due to the weight of the cylindrical battery (10) can be prevented from differing from the design value, and thus the smooth rupture of the venting portion (310) can be secured.

[0064] Referring to FIGS. 4 and 5, the lower end of the first bend portion (320) may be positioned lower than the lower end of the central region (S3) and the lower end of the edge region (S1). The lower end of the downwardly bent first bend portion (320) may be positioned lower than the lower end of the central region (S3) and the lower end of the edge region (S1).

[0065] According to this configuration of the present invention, the total height of the top cap (300) can be reduced compared to a case where the first bending portion (320) has an upwardly convex shape or the lower end of the first bending portion (320) is equal to or higher than the lower end of the central region (S3) and the lower end of the edge region (S1). Accordingly, the height of the electrode assembly (100) can be increased by the amount of the height reduced by the top cap (300), thereby improving the energy density.

[0066] Referring to FIG. 7, the bending region (S2) may include a second bending portion (330) that is bent convexly upward. The central region (S3) may include a second bending portion (330) that is bent convexly upward. That is, the second bending portion (330) that is bent convexly upward may be provided in the bending region (S2) and / or the central region (S3). However, as shown in FIG. 8, the second bending portion (330) may also have a shape that is bent convexly downward.

[0067] Additionally, the bending region (S2) and / or the central region (S3) may be provided with two or more additional bends bent downwardly or upwardly.

[0068] Referring to Fig. 7, the upper end of the second bending portion (330) may be at the same height as the upper end of the battery housing (200). The upper end of the second bending portion (330) bent upward may be at the same height as the upper end of the battery housing (200).

[0069] According to this configuration of the present invention, when the opening (O) is located at the bottom, the battery can be supported more stably because it is supported not only by the battery housing (200) but also by the second bending portion (330). In addition, when the venting portion (310) to be described later is provided in the top cap (300), and when this venting portion (310) is formed further inward from the center than the second bending portion (330), the crimping pressure can be absorbed by the second bending portion (330), so that the phenomenon in which force is applied to the venting portion (310) and the pressure required for breakage or fracture of the venting portion (310) differs from the design value can be prevented. In addition, when two or more multiple bending portions are provided, the crimping pressure that the top cap can absorb can be increased.

[0070] Referring again to FIGS. 1 to 10, the top cap (300) according to the present invention may have a venting portion (310) that is configured to be more vulnerable compared to the peripheral region. The venting portion (310) may have a thinner thickness compared to the peripheral region. The venting portion (310) may be provided in the central region (S3). The venting portion (310) may be formed by notching on one side or both sides of the top cap (300) to partially reduce the thickness of the top cap (300).

[0071] According to this configuration of the present invention, when an abnormality occurs in the battery and the internal pressure of the battery housing (200) increases to a certain level, the venting part (310) may be broken and gas may be discharged.

[0072] Referring to FIGS. 1 and 11, a cylindrical battery (10) according to the present invention may include a first current collector (400). The first current collector (400) may be positioned between the electrode assembly (100) and the top cap (300). The first current collector (400) may have a first tab coupling portion (410) electrically coupled to the first electrode tab (110). The first current collector (400) may have a housing coupling portion (420) coupled to the inner surface of the battery housing (200).

[0073] A first bend (320) may be positioned on the housing coupling portion (420). The first bend (320) may be positioned to be in contact with and seated on the housing coupling portion (420). However, even if the first bend (320) does not contact or meet, the first bend (320) may be positioned to overlap the housing coupling portion (420) along the extension direction of the Z-axis. If the top cap is configured to not have polarity, at least the first bend (320) that meets the housing coupling portion (420) may be insulated.

[0074] According to this configuration of the present invention, when the housing coupling portion (420) moves due to gas generation inside the battery or external impact, the upward movement (positive direction of the Z-axis) can be controlled by the first bending portion (320). Therefore, the housing coupling portion (420) can be stably coupled to the battery housing (200).

[0075] Referring to FIGS. 1 and 11, a cylindrical battery (10) according to the present invention may include a terminal (T), a second current collector (P), and an insulator (I).

[0076] The terminal (T) can be electrically connected to the second electrode tab (120). The terminal (T) can be electrically connected to the second electrode tab 120 by penetrating a closed portion of the battery housing (200) provided on the opposite side of the opening portion (O) of the battery housing (200). The terminal (T) can penetrate approximately the center of the lower surface of the battery housing (200). The terminal (T) can be electrically connected to the electrode assembly (100) by being coupled to a second current collector (P) to be described later.

[0077] The second current collector (P) may be electrically coupled to the second electrode tab (120). The second current collector (P) may be electrically coupled to the terminal (T). The second current collector (P) may have a terminal coupling portion coupled to the terminal (T) and a second tab coupling portion coupled to the second electrode tab (120).

[0078] An insulator (I) may be positioned on the second electrode tab (120) to insulate the battery housing (200) and the second electrode tab (120). The insulator (I) may be interposed between the closing portion of the battery housing (200) and the electrode assembly (100) or between the closing portion of the battery housing (200) and the second current collector (P). The insulator (I) may include, for example, a resin material having insulating properties. The insulator (I) may have a hole approximately in the center so that the terminal (T) can be electrically connected to the second electrode tab (120).

[0079] Fig. 12 is a drawing showing a battery pack (2) according to the present invention.

[0080] Referring to FIG. 12, a battery pack (2) according to the present invention may include a cylindrical battery (10). The battery pack (2) may further include various components other than the cylindrical battery (10), such as components of the battery pack (2) known at the time of filing of the present invention, such as a BMS, a bus bar, a pack case, a relay, a current sensor, etc.

[0081] When the cylindrical battery (10) included in the battery pack (2) as illustrated in FIG. 12 is positioned with the top cap (300) facing downward, the battery housing (200) functioning as the first electrode terminal and the terminal (T) functioning as the second electrode terminal are positioned at the top. Therefore, electrical connection can be easily made at the top. In addition, as described above, since the venting portion (310) does not touch the ground or the bottom surface of the housing for module or pack configuration, the phenomenon in which the pressure required for the rupture of the venting portion (310) differs from the design value due to the weight of the cylindrical battery (10) can be prevented, and thus, the smooth rupture of the venting portion (310) can be secured.

[0082] Fig. 13 is a drawing showing a vehicle (1) according to the present invention.

[0083] Referring to FIG. 13, a vehicle (1) according to the present invention may include a battery pack (2). The vehicle (1) may be a hybrid vehicle (1) or an electric vehicle (1). In addition to the battery pack (2), the vehicle (1) according to the present invention may further include various other components included in the vehicle (1). For example, in addition to the battery pack (2) according to the present invention, the vehicle (1) according to the present invention may further include a body, a motor, a control device such as an ECU (electronic control unit), etc.

[0084] As described above, the present invention has been described with reference to the attached drawings, focusing on preferred embodiments. However, it will be apparent to those skilled in the art that numerous obvious modifications can be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be construed as encompassing such numerous modifications by the appended claims.

Claims

1. An electrode assembly having a first electrode tab and a second electrode tab; a battery housing accommodating the electrode assembly through an opening formed at the top; and A top cap configured to cover the opening, the top cap including a bending region having an edge region, a center region located relatively further inward compared to the edge region, and a first bending region located between the edge region and the center region and having a shape that is convexly bent downward; A cylindrical battery containing:

2. In paragraph 1, A cylindrical battery characterized in that the central region is positioned higher than the edge region.

3. In paragraph 2 A cylindrical battery, characterized in that the upper part of the battery housing is positioned higher than the upper part of the central region.

4. In paragraph 1, A cylindrical battery characterized in that the lower end of the first bending portion is positioned lower than the lower end of the central region and the lower end of the edge region.

5. In paragraph 1, The above bending area is, A cylindrical battery characterized by including a second bending portion having a shape that is convexly bent upward.

6. In paragraph 1, The above central area is, A cylindrical battery characterized by including a second bending portion having a shape that is convexly bent upward.

7. In paragraph 5, A cylindrical battery, characterized in that the upper end of the second bending portion is at the same height as the upper end of the battery housing.

8. In paragraph 1, The above top cap is, A cylindrical battery characterized by having a venting portion that is configured to be vulnerable compared to the surrounding area.

9. In paragraph 8, The above venting part, A cylindrical battery characterized by having a thinner thickness compared to the surrounding area.

10. In paragraph 8, The above venting part, A cylindrical battery characterized by being provided in the above central region.

11. In paragraph 8, A cylindrical battery characterized in that the top cap is configured to have no polarity.

12. In paragraph 1, The above cylindrical battery, a first electrode coupling portion electrically coupled to the first electrode tab; and A housing coupling portion coupled to the inner surface of the battery housing; Equipped with, A cylindrical battery characterized by including a first current collector positioned between the electrode assembly and the top cap.

13. In paragraph 12, A cylindrical battery, characterized in that the first bending portion is located on the housing joint portion.

14. A battery pack comprising a cylindrical battery according to any one of claims 1 to 13.

15. A vehicle including a battery pack according to Article 14.

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