Cylindrical battery and battery pack

Abstract

The invention relates to the technical field of cylindrical batteries, and discloses a cylindrical battery and a battery pack, wherein a cylindrical battery comprises a shell, the shell comprises a first end face, a second end face and a peripheral face which are arranged oppositely, the first end face and the second end face are arranged oppositely, the peripheral face is located between the first end face and the second end face, a recessed portion is arranged on the bottom wall of the recessed portion, a liquid injection hole is arranged on the side wall of the recessed portion and the liquid injection hole, a groove is arranged between the side wall of the recessed portion and the liquid injection hole, a distance d between the groove and the liquid injection hole along the radial direction of the bottom wall of the recessed portion, a depth of the groove is h, a depth of the recessed portion is H, and a range of d*h / H is 0.01-100, in mm; a sealing nail cap is arranged on the first end face and is welded to the bottom wall of the recessed portion, and the invention solves the problem of cold welding between the sealing nail cap and the step portion of the step hole, which affects product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of cylindrical batteries, and in particular to a cylindrical battery and a battery pack. Background Art

[0002] Cylindrical batteries are batteries with high capacity, long cycle life and wide application range. The shell of cylindrical batteries is usually provided with a liquid injection hole for injecting electrolyte.

[0003] In the related art, the injection hole of the cylindrical battery is generally arranged at one end of the cylindrical battery shell, and there is a step hole around the injection hole, and the injection hole is located at the bottom of the step hole.

[0004] However, in the above-mentioned related technologies, material extrusion may occur at the edge of the step hole during the stamping process, causing the bottom edge of the step hole to bulge toward the hole mouth. During the subsequent welding of the sealing nail cap, the contact between the sealing nail cap and the step part is unstable due to the influence of the bulge at the bottom edge of the step hole, which may easily cause cold welding, and may lead to insufficient connection strength of the sealing nail cap, or even battery leakage, affecting product quality. Summary of the invention

[0005] In view of this, the present invention provides a cylindrical battery and a battery pack to solve the problem of poor welding between a sealing nail cap and a step portion of a step hole, which affects product quality.

[0006] In the first aspect, the present invention provides a cylindrical battery, including a shell, the shell including a first end face, a second end face and a peripheral surface, the first end face and the second end face are arranged opposite to each other, the peripheral surface is located between the first end face and the second end face and is arranged around the first end face and the second end face, the first end face, the second end face and the peripheral surface together form a accommodating cavity, the battery cell is arranged in the accommodating cavity, a recessed portion is provided on the first end face facing the battery cell, a liquid injection hole is provided on the bottom wall of the recessed portion, a groove is provided between the side wall of the recessed portion and the liquid injection hole, the distance between the groove and the liquid injection hole along the radial direction of the bottom wall of the recessed portion is d, the depth of the groove is h, the depth of the recessed portion is H, and the range of d×h / H is 0.01-100, in mm; a sealing nail cap is provided on the first end face and is welded to the bottom wall of the recessed portion.

[0007] Beneficial effect: by setting a groove at the bottom of the concave part, when the step hole is punched on the shell of the cylindrical battery, the material on the shell is squeezed and the material transferred is transferred to the direction of the groove, and the groove can accommodate excess material, thereby reducing the formation of extrusion bulges at the bottom of the concave part, avoiding the unevenness of the bottom surface of the concave part, and reducing the possibility of affecting the subsequent sealing nail cap welding quality and causing false welding. When d increases, less material is accumulated, and the depth of the groove can be reduced. When the end face is punched to form a concave part, the deeper the depth of the concave part, the more material is piled on the edge, but the range of the concave part cannot be too large. Due to the limited area of ​​the end face, when the concave part is too large, the remaining area of ​​the first end face will be too small, and the battery support area will be insufficient; if the formula range is too small, the depth of the concave part is too deep, and the internal space utilization rate of the battery will be reduced accordingly.

[0008] In an optional embodiment, the groove is provided at the connection between the bottom wall and the side wall of the recessed portion, and the range of d×h / H is 0.1-100, in mm.

[0009] In an optional embodiment, the distance d between the groove and the injection hole along the radial direction of the bottom wall of the recessed portion is in the range of 0.2-10, in mm.

[0010] In an optional embodiment, the depth h of the groove is in the range of 0.05-1, in mm.

[0011] In an optional implementation, the ratio of the groove depth h to the recessed portion depth H is in the range of 0.05-10.

[0012] In an optional embodiment, the groove is continuously arranged at the connection between the bottom wall and the side wall of the recessed portion.

[0013] In an optional embodiment, the groove is discontinuously arranged at the connection between the bottom wall and the side wall of the recessed portion.

[0014] In an optional embodiment, the side wall of the recessed portion is inclined.

[0015] In an optional embodiment, the angle between the side wall of the recessed portion and the bottom wall of the recessed portion is in the range of 90°-150°.

[0016] In an optional embodiment, the sealing nail cap and the projections of the groove on the bottom wall of the recessed portion are staggered.

[0017] In an optional embodiment, the distance between the edge of the sealing nail cap and the groove along the radial direction of the bottom wall of the recessed portion is 0-4, in mm.

[0018] In an optional embodiment, the bottom of the groove is configured as a curved surface.

[0019] In an optional embodiment, a vertical wall extending toward the inner side of the shell is provided on the shell at the injection hole.

[0020] In an optional embodiment, the height of the vertical wall ranges from 0.1 to 5, in mm.

[0021] In a second aspect, the present invention further provides a battery pack, comprising: at least one cylindrical battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic diagram of the overall structure of a cylindrical battery according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 An enlarged structural diagram of part A in the content shown;

[0025] Figure 3 A schematic cross-sectional structure diagram of a cylindrical battery according to an embodiment of the present invention showing the positional relationship between a groove, a recessed portion and a liquid injection hole;

[0026] Figure 4 for Figure 3 A schematic diagram of the enlarged structure of part B;

[0027] Figure 5 This is a schematic diagram of an exploded structure of a cylindrical battery according to an embodiment of the present invention, which is used to illustrate the positional relationship between the battery cell and the shell.

[0028] Description of reference numerals:

[0029] 100, shell; 101, first end surface; 102, second end surface; 104, accommodating cavity; 200, recessed portion; 201, groove; 300, liquid injection hole; 301, vertical wall; 400, battery cell. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] In the related art, a step hole is usually provided at the injection hole of a cylindrical battery for welding and accommodating a sealing nail cap, and the step hole needs to be formed by stamping the battery shell. During the stamping process of the step hole, the material of the battery shell located at the step hole is squeezed and transferred to the non-extruded part, or to the position with less extrusion force, that is, the "material extrusion" phenomenon occurs, so that some irregular protrusions are formed at the bottom edge of the step hole. These protrusions will cause the sealing nail cap to partially warp up during the subsequent welding process of the sealing nail cap, resulting in a cold weld, affecting the welding strength between the sealing nail cap and the cylindrical battery shell, which may cause the battery to leak during subsequent use.

[0032] The embodiment of the present application proposes a cylindrical battery and a battery pack. By arranging a groove in the step hole, a holding space is provided for the extruded material during the stamping process of the step hole. After the extruded material moves to the groove position, it will not be "extruded" with the material at the side edge of the step hole, thereby not forming a bulge, avoiding affecting the welding of the sealing nail cap, and improving the reliability of the product.

[0033] Combine the following Figures 1 to 5 , describing an embodiment of the present invention.

[0034] According to an embodiment of the present invention, on the one hand, a cylindrical battery and a battery pack are provided. Figures 1 to 4, including a shell 100, the shell 100 includes a first end face 101, a second end face 102 and a peripheral surface which are arranged opposite to each other, the first end face 101 and the second end face 102 are arranged opposite to each other, the peripheral surface is located between the first end face 101 and the second end face 102 and is arranged around the first end face 101 and the second end face 102, the first end face 101, the second end face 102 and the peripheral surface together form a receiving cavity 104, the battery cell 400 is arranged in the receiving cavity 104, the first end face 101 is provided with a recessed portion 200 facing the battery cell 400, the recessed portion 200 and the first end face 101 are integrally formed, a liquid injection hole 300 is arranged on the bottom wall of the recessed portion 200, a groove 201 is arranged between the side wall of the recessed portion 200 and the liquid injection hole 300, the distance between the groove 201 and the liquid injection hole 300 along the radial direction of the bottom wall of the recessed portion 200 is d, the depth of the groove 201 is h, the depth of the recessed portion 200 is H, and the range of d×h / H is 0.01-100, in units of mm; a sealing nail cap is arranged on the first end face 101 and is welded to the bottom wall of the recessed portion 200.

[0035] Illustratively, the value of d×h / H may be 0.01 mm, 0.03 mm, 0.1 mm, 1 mm, 12 mm, 50 mm, or 100 mm.

[0036] In this embodiment, by setting a groove 201 at the bottom of the recessed part 200, when the step hole is punched on the shell 100 of the cylindrical battery, the material on the shell 100 is squeezed and the transferred material is transferred to the direction of the groove 201, and the groove 201 can accommodate excess material, thereby reducing the formation of a material extrusion bulge at the bottom of the recessed part 200, avoiding the unevenness of the bottom surface of the recessed part 200, and reducing the possibility of affecting the subsequent sealing nail cap welding quality and causing a cold weld. When d increases, the accumulated material is less, and the depth of the groove 201 can be reduced. When the end face is punched to form the recessed part 200, the deeper the depth of the recessed part 200, the more material is piled on the edge, but the range of the recessed part 200 cannot be too large. Due to the limited end face area, when the recessed part 200 is too large, the remaining area of ​​the first end face 101 will be too small, and the battery support area will be insufficient; if the formula range is too small, the depth of the recessed part 200 is too deep, and the internal space utilization rate of the battery will be reduced accordingly.

[0037] In one embodiment, the groove 201 is disposed at the connection between the bottom wall and the side wall of the recessed portion 200 , and the preferred range of d×h / H is 0.1-100, in mm.

[0038] Exemplarily, the value of d×h / H may be 0.1 mm, 0.5 mm, 1 mm, 5 mm, 24.5 mm, 50 mm, 69 mm, or 100 mm.

[0039] In this embodiment, since the groove 201 is arranged at the connection between the bottom wall and the side wall of the recessed portion 200, that is, at the edge of the bottom wall of the recessed portion 200, the depth of the groove 201 satisfies 0.05≤d×h / H≤1 to ensure that the extruded material can be fully accommodated.

[0040] In one embodiment, the distance d between the groove 201 and the injection hole 300 along the radial direction of the bottom wall of the recessed portion 200 is in the range of 0.2-10, in mm.

[0041] Exemplarily, the value of d may be 0.2 mm, 0.55 mm, 3 mm, 8 mm or 10 mm.

[0042] In this embodiment, by controlling the range of d, it is prevented that d is too small, resulting in a too small welding area of ​​the sealing nail cap, affecting the welding strength of the sealing nail cap. At the same time, it is also prevented that d is too large, resulting in insufficient support area on the bottom surface of the battery and reduced battery stability.

[0043] In one embodiment, the depth h of the groove 201 is in the range of 0.05-1, in mm.

[0044] Exemplarily, the value of h may be 0.05 mm, 0.6 mm, 0.8 mm, 0.95 mm or 1 mm.

[0045] In this embodiment, since the groove 201 is directly disposed on the first end surface 101, a too large depth h of the groove 201 will affect the strength of the bottom wall, while a too small depth h of the groove 201 will not be able to completely accommodate the extruded material, affecting the flatness of the plane used for welding the sealing nail cap.

[0046] In one embodiment, the ratio of the depth h of the groove 201 to the depth H of the recessed portion 200 is in the range of 0.05-10.

[0047] Illustratively, the ratio of h to H can be 0.05, 0.08, 0.1, 0.55, 6, 8, or 10.

[0048] In this embodiment, as the depth H of the recessed portion 200 increases, more material is piled on the bottom wall of the recessed portion 200, and the depth h of the groove 201 also needs to increase accordingly; by controlling the ratio of h / H, the ratio is prevented from being too small, resulting in the recessed portion 200 being too deep and affecting the space utilization; at the same time, it is also prevented from being too large, resulting in the recessed portion 201 being too deep and affecting the strength of the bottom wall of the recessed portion 200.

[0049] In one embodiment, the groove 201 is continuously disposed at the connection between the bottom wall and the side wall of the recessed portion 200 .

[0050] In this embodiment, the grooves 201 are continuously arranged so that the grooves 201 have more space to accommodate materials and can make the materials flow more evenly, which helps to improve the flatness of the bottom wall of the recessed portion 200 and improve the welding quality of the sealing nail cap.

[0051] In one embodiment, the groove 201 is discontinuously disposed at the connection between the bottom wall and the side wall of the recessed portion 200 .

[0052] In this embodiment, the discontinuous arrangement of the grooves 201 can effectively reduce the influence of the arrangement of the grooves 201 on the bottom wall strength of the recessed portion 200 .

[0053] In one embodiment, the sidewall of the recessed portion 200 is inclined.

[0054] In this embodiment, by tilting the side wall of the recessed portion 200 , when the recessed portion 200 is formed by punching the housing 100 , the extruded material can flow more smoothly into the groove 201 .

[0055] In one embodiment, the angle between the side wall of the recessed portion 200 and the bottom wall of the recessed portion 200 is in the range of 90°-150°.

[0056] Specifically, the angle between the side wall and the bottom wall of the recessed portion 200 may be 90°, 95°, 118°, 125.8°, 140° or 150°.

[0057] In this embodiment, by controlling the angle between the side wall and the bottom wall of the recessed portion 200, the angle is prevented from being too small, which would reduce the distance from the edge of the injection hole 300 to the groove 201, thereby reducing the welding surface area for welding the sealing nail cap and affecting the welding quality.

[0058] In one embodiment, the sealing nail cap and the projection of the groove 201 on the bottom wall of the recessed portion 200 are staggered.

[0059] In this embodiment, since the groove 201 cannot contact the sealing nail cap and provide a connection when the sealing nail cap is welded, the staff offsets the sealing nail cap and the groove 201 so that the welding plane of the sealing nail cap is offset from the groove 201, thereby increasing the plane area used for welding the sealing nail cap and avoiding the influence of the groove 201 on the welding of the sealing nail cap.

[0060] In one embodiment, the distance between the edge of the sealing nail cap and the groove 201 along the radial direction of the bottom wall of the recessed portion 200 is 0-4, in mm.

[0061] Exemplarily, the distance between the edge of the sealing nail cap and the groove 201 along the radial direction of the bottom wall of the recessed portion 200 may be 0 mm, 0.2 mm, 0.85 mm, 1.5 mm, 3 mm or 4 mm.

[0062] In this embodiment, by controlling the distance between the sealing nail cap and the edge of the groove 201, it is prevented that when the distance is too small, the unevenness of the edge of the groove 201 affects the welding quality of the sealing nail cap. At the same time, it is also prevented that when the distance is set too large, the sealing nail cap is smaller in size, and thus cannot form a sufficient welding area with the bottom surface of the recessed portion 200, thereby affecting the welding strength.

[0063] In one embodiment, the bottom of the groove 201 is configured as a curved surface.

[0064] In this embodiment, by setting the bottom of the groove 201 as an arc surface, the material flowing into the groove 201 is guided to prevent the material from being locally accumulated in the groove 201 and affecting the subsequent material from entering.

[0065] In one embodiment, a vertical wall 301 extending toward the inside of the housing 100 is provided on the housing 100 at the injection hole 300 .

[0066] In this embodiment, by providing a vertical wall 301, the bottom wall strength of the recessed portion 200 can be further enhanced to ensure the straightness of the bottom wall of the recessed portion 200. At the same time, the channel formed by the vertical wall 301 corresponds to the battery core hole, so that the liquid electrolyte can better infiltrate the battery cell 400.

[0067] In one embodiment, the height of the vertical wall 301 ranges from 0.1 to 5 mm.

[0068] Exemplary heights of the vertical walls 301 may be 0.1 mm, 0.85 mm, 1 mm, 2.8 mm, 4 mm, or 5 mm.

[0069] In this embodiment, by limiting the height of the vertical wall 301, on the one hand, it is prevented that the vertical wall 301 is too high, which reduces the space utilization rate in the shell 100 and affects the battery performance; on the other hand, it is prevented that the vertical wall 301 is too short, fails to strengthen the bottom wall, and has a weak ability to guide the liquid electrolyte, thereby ensuring product quality.

[0070] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising: at least one cylindrical battery as described above.

[0071] In this embodiment, the battery pack is manufactured by using the cylindrical battery. Due to the cylindrical battery, the possibility of leakage in the battery pack due to poor welding between the sealing nail cap of the cylindrical battery and the step portion of the step hole is avoided, thereby improving the quality of the battery pack product.

[0072] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cylindrical battery, characterized in that: include: The housing (100) comprises a first end surface (101), a second end surface (102) and a peripheral surface, wherein the first end surface (101) and the second end surface (102) are arranged opposite to each other, the peripheral surface is located between the first end surface (101) and the second end surface (102) and is arranged around the first end surface (101) and the second end surface (102), the first end surface (101), the second end surface (102) and the peripheral surface together form a receiving cavity (104), the battery cell (400) is arranged in the receiving cavity (104), a recessed portion (200) is arranged on the first end surface (101) facing the battery cell (400), a liquid injection hole (300) is arranged on the bottom wall of the recessed portion (200), and the recessed portion (200) is provided with a liquid injection hole (300). A groove (201) is provided between the side wall and the injection hole (300); the distance between the groove (201) and the injection hole (300) along the radial direction of the bottom wall of the recessed portion (200) is d; the depth of the groove (201) is h; the depth of the recessed portion (200) is H; and the range of d×h / H is 0.01-100, in mm; the range of the distance d between the groove (201) and the injection hole (300) along the radial direction of the bottom wall of the recessed portion (200) is 0.2-10, in mm; the range of the depth h of the groove (201) is 0.05-1, in mm; and the range of the ratio of the depth h of the groove (201) to the depth H of the recessed portion (200) is 0.05-10; A sealing nail cap is provided on the first end surface (101) and is welded to the bottom wall of the recessed portion (200).

2. The cylindrical battery according to claim 1, characterized in that: The groove (201) is provided at the connection between the bottom wall and the side wall of the recessed portion (200), and the range of d×h / H is 0.1-100, in mm.

3. The cylindrical battery according to claim 1, characterized in that: The groove (201) is continuously arranged at the connection between the bottom wall and the side wall of the recessed portion (200).

4. The cylindrical battery according to claim 1, characterized in that: The groove (201) is discontinuously arranged at the connection between the bottom wall and the side wall of the recessed portion (200).

5. The cylindrical battery according to claim 1, characterized in that: The side wall of the recessed portion (200) is arranged inclined.

6. The cylindrical battery according to claim 5, characterized in that: The included angle between the side wall of the recessed portion (200) and the bottom wall of the recessed portion (200) is in the range of 90°-150°.

7. The cylindrical battery according to claim 1, characterized in that: The projections of the sealing nail cap and the groove (201) on the bottom wall of the recessed portion (200) are staggered.

8. The cylindrical battery according to claim 7, characterized in that: The distance between the edge of the sealing nail cap and the groove (201) along the radial direction of the bottom wall of the recessed portion (200) is 0-4, in mm.

9. The cylindrical battery according to claim 1, characterized in that: The bottom of the groove (201) is configured as a curved surface.

10. The cylindrical battery according to claim 1, characterized in that: A vertical wall (301) extending toward the inside of the shell (100) is provided on the shell (100) at the injection hole (300).

11. The cylindrical battery according to claim 10, characterized in that: The height of the vertical wall (301) ranges from 0.1 to 5, in mm.

12. A battery pack, characterized in that: include: At least one cylindrical battery as claimed in any one of claims 1 to 11.

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