Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a kind of secondary battery, battery pack and electronic device, comprising: shell, including end wall and side wall;Electrode assembly;Pole, with accommodating groove, the opening of accommodating groove is arranged in the end of pole away from electrode assembly;Sealing nail is contained in accommodating groove, the outer periphery of sealing nail includes sequentially connected first circumferential side wall, second circumferential side wall, sealing nail also includes the first wall being connected with second circumferential side wall, second circumferential side wall compared with the axial direction of sealing nail has first inclination angle, the angle of first inclination angle is K1 °, the included angle between first circumferential side wall and the axial direction of sealing nail is K3 °, accommodating groove includes the third circumferential side wall and second wall being connected;Along the axial direction of sealing nail, first wall is opposite and spaced apart from second wall;Third circumferential side wall compared with the axial direction of pole has second inclination angle, the angle of second inclination angle is K2 °, K1> K2> K3.The utility model at least avoids the assembly error between sealing nail and pole to cause the influence welding quality.

Description

Technical Field

[0001] This utility model relates to a secondary battery, a battery pack, and an electronic device. Background Technology

[0002] In the field of new energy power batteries, the application of secondary batteries is becoming increasingly widespread. For example, secondary batteries (such as lithium-ion batteries) can be used in electronic devices such as vehicles, energy storage, mobile phones, tablets, wearable devices, power banks, e-cigarettes, digital products, power tools, power units, and energy storage devices. Secondary batteries typically consist of a casing and electrode assemblies. The electrode assembly includes a positive electrode, a first separator, a negative electrode, and a second separator, which are stacked sequentially to form a wound electrode assembly or a stacked electrode assembly, and then encapsulated within the casing.

[0003] When the sealing pin of the secondary battery is assembled to the terminal post, there are errors in the assembly between the sealing pin and the terminal post, which affects the welding quality. Utility Model Content

[0004] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery, battery pack and electronic device, so as to at least avoid the welding quality being affected by the assembly error between the sealing nail and the terminal post.

[0005] To achieve the above objectives, this utility model provides a secondary battery, comprising: a housing, including an end wall and side walls surrounding the end wall; an electrode assembly housed within the housing; a terminal post having a receiving groove, the opening of which is located at the end of the terminal post away from the electrode assembly; and a sealing pin housed in the receiving groove. Along the direction from the opening of the receiving groove to the electrode assembly, the outer periphery of the sealing pin includes a first peripheral side wall and a second peripheral side wall connected sequentially. The sealing pin also includes a first wall connected to the second peripheral side wall, the second peripheral side wall having a [missing information - likely a axial distance] relative to the axial direction of the sealing pin. The first tilt angle is K1°, and the included angle between the first circumferential sidewall and the axial direction of the sealing pin is K3°. The receiving groove includes a third circumferential sidewall and a second wall connected to each other. Along the axial direction of the sealing pin, the first wall and the second wall are opposite to and spaced apart. Along the radial direction of the pole post, at least a portion of the first circumferential sidewall and the second circumferential sidewall are opposite to the third circumferential sidewall. The first circumferential sidewall and the third circumferential sidewall are welded together. The third circumferential sidewall has a second tilt angle relative to the axial direction of the pole post, and the angle of the second tilt angle is K2°, where K1 > K2 > K3.

[0006] In some embodiments, K1-K2 < 5; and / or, K3 = 0.

[0007] In some embodiments, the sealing pin includes a body and a connecting portion. The first and second peripheral sidewalls are peripheral sidewalls of the connecting portion. The surface of the connecting portion away from the electrode assembly includes a first annular connecting surface and an annular groove. The annular groove is disposed around the body. The annular groove and the first peripheral sidewall are connected through the first annular connecting surface. In this embodiment, the outer diameter of the first peripheral sidewall is R1 mm along the radial direction of the sealing pin, the width of the first annular connecting surface is W2 mm, and 0.02 ≤ W2 / R1 ≤ 0.2.

[0008] In some embodiments, the height of the body of the sealing pin in the axial direction is H6 mm, and the minimum height of the connecting part between the annular groove and the first wall is H5 mm, wherein 0.15×H6≤H5≤0.5×H6.

[0009] In some embodiments, the receiving groove is a stepped hole, comprising: a first hole segment, a second hole segment, and a third hole segment that are sequentially continuous and have progressively decreasing diameters; an opening is located at one end of the first hole segment away from the electrode assembly; a second wall is an annular stepped surface that connects the second hole segment and the third hole segment; the hole wall of the second hole segment is a third circumferential sidewall; wherein, in the axial direction of the sealing pin, the distance between the first wall and the second wall of the sealing pin is H3 mm, wherein 0.02 ≤ H3 ≤ 0.2; and / or, the height of the first circumferential sidewall in the axial direction of the sealing pin is H1 mm, wherein 0.05 ≤ H1 ≤ 0.3; and / or, in the axial direction of the electrode post, the height of the first hole segment is H4 mm, and the height of the second hole segment is H7 mm, wherein 0.1 × H7 ≤ H4 ≤ 0.6 × H7.

[0010] In some embodiments, the pole includes a column portion, an outer flange, and an inner flange. The outer flange is connected to the column portion outside the housing and extends along an axis away from the pole. The inner flange is connected to the column portion inside the housing and extends along an axis away from the pole. A receiving groove is disposed in the column portion. In the axial direction of the pole, the distance between the hole wall of the first hole segment and the first circumferential sidewall is W3 mm. The outer sidewall of the outer flange away from the axis of the pole is connected to the hole wall of the first hole segment through a second annular connecting surface. The width of the second annular connecting surface along the radial direction of the pole is W4 mm, and 0.1≤W3 / W4≤0.6.

[0011] In some embodiments, the height of the body is greater than the height of the connection portion in the axial direction of the sealing pin, away from the electrode assembly.

[0012] In some embodiments, the distance from one end of the second peripheral sidewall near the electrode assembly to the third peripheral sidewall is H2 mm, where 0.02 ≤ H2 ≤ 0.2.

[0013] Embodiments of this application also provide a battery pack, including a plurality of secondary batteries as described above and at least one busbar, wherein the sealing pin of any one of the plurality of secondary batteries is connected to the casing of another secondary battery through the busbar.

[0014] Embodiments of this application also provide an electronic device including a battery pack of any of the above.

[0015] The beneficial technical effect of this utility model is at least to avoid the fact that assembly errors between the sealing nail and the pole post affect the welding quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of an electronic device, using a vehicle as an example, is shown.

[0018] Figure 2 A perspective view of a secondary battery according to an embodiment of this application is shown.

[0019] Figure 3 A top view schematic diagram of a secondary battery according to an embodiment of this application is shown.

[0020] Figure 4 It shows Figure 3 A schematic diagram of the axial cross-section of the secondary battery taken along section line AA.

[0021] Figure 5 It shows Figure 4 A magnified view of a portion of region B in the middle.

[0022] Figure 6 It shows Figure 5 A magnified view of a portion of region C.

[0023] Figure 7 It shows Figure 5 A magnified view of a portion of region D. Detailed Implementation

[0024] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0025] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0026] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.

[0027] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0028] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0029] In existing technologies, the electrode post has a groove to accommodate the sealing pin, and the inner wall of the groove is parallel to or substantially parallel to the axial direction of the electrode post. This makes it relatively easy for suppliers to manufacture and for product dimensions to be easily inspected. However, this structure lacks a guiding function, making it difficult to assemble and position the sealing pin. During assembly, it is easy for the sealing pin and groove to be misaligned, resulting in eccentric assembly of the sealing pin. This leads to a localized increase in the circumferential gap between the sealing pin and the groove, and unstable position and shape of the molten pool generated during welding of the same product, affecting the welding quality. Due to the above problems in welding the sealing pin and electrode post, existing secondary batteries are not satisfactory.

[0030] See Figure 1This utility model provides an electronic device 1000, which includes a battery pack 1002. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. As an example, the electronic device 1000 is a vehicle, which can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part is the vehicle body, and the battery pack 1002 is located at the bottom of the vehicle body, providing electrical power for the vehicle's operation or the operation of its internal electrical components. However, in other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can obtain electrical power from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electronic device 1000.

[0031] For ease of explanation, the following embodiments use a vehicle as an example to illustrate the concept of electronic device 1000. See also Figure 1 The vehicle is equipped with a battery pack 1002, which can be located at the bottom, front, or rear of the vehicle body 1001. The battery pack 1002 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. Figure 2 A perspective view of a secondary battery 100 according to an embodiment of this application is shown. Figure 3 A cross-sectional schematic diagram of a secondary battery 100 according to an embodiment of this application is shown. Figure 4 It shows Figure 3 A schematic diagram of the cross-section taken along section line AA.

[0032] In one example of the secondary battery of this utility model, see Figure 2 , Figure 3 and Figure 4 The electrode assembly 120 is sealed and installed within the housing 200. The electrode assembly 120 has a first electrode tab and a second electrode tab at both ends of the secondary battery 100 along its height direction, and the first and second electrode tabs have opposite polarities, with the first electrode tab facing the opening side and being the negative electrode tab. It should be noted that in other embodiments, the first electrode tab can also be the positive electrode tab, and the second electrode tab can be the negative electrode tab.

[0033] The electrode assembly 120 of the secondary battery 100 is mainly formed by winding and placing a positive electrode sheet and a negative electrode sheet, and typically a first separator and a second separator are provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive active material layer, the positive active material layer being coated on the surface of the positive current collector; the positive current collector includes a positive electrode coating area and a positive electrode tab connected to the positive electrode coating area, the positive electrode coating area being coated with the positive active material layer, and the positive electrode tab not being coated with the positive active material layer. The negative electrode sheet includes a negative current collector and a negative active material layer, the negative active material layer being coated on the surface of the negative current collector; the negative current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area, the negative electrode coating area being coated with the negative active material layer, and the negative electrode tab not being coated with the negative active material layer. Taking a lithium-ion battery as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The first and second separators can be made of PP or PE, etc. To protect and insulate the electrode assembly 120, an insulating film can be wrapped around the outside of the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0034] In some embodiments, the housing 200 is made of materials such as copper, iron, aluminum, steel, or aluminum alloy, preferably steel (e.g., SPCC) for higher strength. To prevent the housing 200 from rusting during long-term use, a rust-preventive material such as metallic nickel can be plated on the surface of the housing 200. The electrode assembly 120 is sealed and installed inside the housing 200.

[0035] Figure 5 It shows Figure 4 A magnified view of a portion of region B in the middle. Figure 6 It shows Figure 5 A magnified view of a portion of region C. Figure 7 It shows Figure 5 A magnified view of a portion of region D. See also Figure 5 and Figure 6The secondary battery 100 includes: a terminal post 300 having a receiving groove 310, the opening of which is located at the end of the terminal post 300 away from the electrode assembly 120; and a sealing pin 150 housed in the receiving groove 310. Along the direction from the opening of the receiving groove 310 to the electrode assembly 120, the outer periphery of the sealing pin 150 includes a first peripheral sidewall 1511 and a second peripheral sidewall 1512 connected in sequence. The second peripheral sidewall 1512 is continuous with the first wall 1515 of the sealing pin 150. The second peripheral sidewall 1512 has a first inclination angle relative to the axial direction of the sealing pin 150, the angle of which is K1°. The included angle between the first peripheral sidewall 1511 and the axial direction of the sealing pin 150 is K3°. The receiving groove 310 includes a third peripheral sidewall 3121 and a second wall 3122 connected in series. Along the axial direction of the sealing pin 150, the first wall 1515 and the second wall 3122 are opposite to and spaced apart. Along the radial direction X of the pole post 300, at least a portion of the first circumferential sidewall 1511 and the second circumferential sidewall 1512 are opposite to the third circumferential sidewall 3121. The first circumferential sidewall 1511 and the third circumferential sidewall 3121 are welded together. The third circumferential sidewall 3121 has a second tilt angle relative to the axial direction of the pole post 300. The angle of the second tilt angle is K2°, where K1 > K2 > K3.

[0036] Specifically, the second circumferential sidewall 1512, which is axially inclined relative to the sealing pin 150, and the third circumferential sidewall 3121, which is axially inclined relative to the pole post 300 (in the direction of the pole post's axis G), cooperate with each other to facilitate the guidance of the sealing pin 150 during loading (e.g., installation into the receiving groove 310). The first inclination angle of the second circumferential sidewall 1512 is greater than the second inclination angle of the third circumferential sidewall 3121, which causes the end of the second circumferential sidewall 1512 away from the electrode assembly 120 to contact the third circumferential sidewall 3121, and there is a gap between the end of the second circumferential sidewall 1512 near the electrode assembly 120 and the third circumferential sidewall 3121. It can be understood that this gap ensures that the end of the second circumferential sidewall 1512 away from the electrode assembly 120 can contact the third circumferential sidewall 3121.

[0037] Furthermore, in the axial direction of the sealing pin 150, a first wall 1515 and a second wall 3122 are positioned opposite each other and spaced apart to prevent interference with the contact between the second and third circumferential sidewalls, thereby ensuring good contact when the sealing pin 150 is welded to the pole post 300. Since the sealing pin 150 and the pole post 300 are welded at the first and third circumferential sidewalls, at least a portion of the first circumferential sidewall 1511 and the second circumferential sidewall 1512 are opposite to the third circumferential sidewall 3121, which facilitates the welding of the sealing pin 150 and the pole post 300.

[0038] If the difference between K1 and K2 is too large, for example, K1 - K2 > 5, the contact area between the second circumferential sidewall 1512 and the third circumferential sidewall 3121 will become smaller accordingly, which may easily lead to welding explosions.

[0039] Furthermore, K1 > K2 > K3 can be set. It should be understood that when K2 > K3, a welding gap is guaranteed between the sealing pin 150 and the pole post 300. In one example, K3 = 0; see [reference needed]. Figure 5 as well as Figure 6 The first sidewall 1511 is a straight segment on the sealing nail 150 that is parallel to the axial direction of the sealing nail 150. This avoids the first sidewall 1511 from blocking the welding laser and facilitates welding between the first sidewall 1511 and the third sidewall 3121.

[0040] See also Figure 5 and Figure 6 Specifically, in some embodiments, the sealing pin 150 includes a body 152 and a connecting portion 151, which is welded to the electrode post 300 to form a welded portion 400. The peripheral sidewall of the connecting portion 151 includes a first peripheral sidewall 1511 and a second peripheral sidewall 1512. The surface of the connecting portion 151 facing away from the electrode assembly 120 includes a first annular connecting surface 1513 and an annular groove 153. The annular groove 153 is disposed around the body 152, and the annular groove 153 and the first peripheral sidewall 1511 are connected through the first annular connecting surface 1513. The welded portion 400 is arranged around the axial direction Z of the electrode post 300, and the annular groove 153 is disposed within the area surrounded by the welded portion 400. The annular groove 153, surrounded by the welded portion 400, at least buffers the heat and stress during welding of the sealing pin 150 to the electrode post 300, preventing weld cracking.

[0041] In some embodiments, along the axial direction of the sealing pin 150 in the direction away from the electrode assembly, the top surface of the body 152 away from the electrode assembly is higher than the highest point of the weld portion 400. Specifically, along the axial direction of the sealing pin 150 in the direction away from the electrode assembly, the height of the body 152 can be set to be greater than the height of the connecting portion 151, or the height of the body 152 can be set to be greater than the height of the second peripheral sidewall 1512. It should be understood that in some cases, the body 152 serves as the welding area with the busbar, and the bodies 152 of at least two secondary batteries 100 can be interconnected via the busbar to form the battery pack 1002 as described above. Setting the top surface of the body 152 higher than the apex of the weld portion 400, which forms the weld pool, can prevent interference in the height direction between the weld portion 400 and the busbar when multiple secondary batteries 100 are welded together via the busbar.

[0042] In the radial direction of the sealing pin 150, the outer diameter of the first circumferential sidewall 1511 is R1 mm, and the width of the first annular connecting surface 1513 is W2 mm, where 0.02 ≤ W2 / R1 ≤ 0.2. If the ratio of W2 / R1 is too large, for example, W2 / R1 > 0.2, the welding area between the body 152 of the sealing pin 150 and the busbar is small; if the ratio of W2 / R1 is too small, for example, W2 / R1 < 0.02, the width of the connecting part 151 is small, and the molten pool formed during the welding process is prone to flow into the annular groove 153, which is prone to explosion and is not conducive to the welding of the sealing pin 150 and the pole post 300.

[0043] In some embodiments, along the Z-axis of the electrode post 300, one end of the first peripheral sidewall 1511 facing away from the electrode assembly 120 is higher than one end of the third peripheral sidewall 3121 facing away from the electrode assembly 120, and the weld portion 400 is a weld mark formed between the first peripheral sidewall 1511 and the third peripheral sidewall 3121. This facilitates the measurement of the sealing pin 150 size, and allows the first peripheral sidewall 1511 to form a gap with the third peripheral sidewall 3121 of the electrode post 300 at the weld joint, facilitating the welding of the sealing pin 150 to the electrode post 300 to form the weld portion 400.

[0044] The height of the first peripheral sidewall 1511 in the axial direction of the sealing pin 150 is H1 mm, where 0.05 ≤ H1 ≤ 0.3. Furthermore, H1 cannot be too small; for example, if H1 < 0.05, the sealing pin 150 will be difficult to process. H1 also cannot be too large; for example, if H1 > 0.3, the excessive height of the first peripheral sidewall 1511 will interfere with laser penetration during laser welding. Based on the aforementioned problems with busbar welding, the first peripheral sidewall 1511 needs to be lower than the top surface of the body 152, and preferably, the height of the first peripheral sidewall 1511 in the axial direction of the sealing pin 150 is set to be less than the height of the body 152.

[0045] See further Figure 5 and Figure 6 In some embodiments, the distance from one end of the second peripheral sidewall 1512 near the electrode assembly 120 to the third peripheral sidewall 3121 is H2 mm, where 0.02 ≤ H2 ≤ 0.2. By designing a gap at the beveled mating point of the electrode post 300 and the sealing pin 150, assembly yield can be guaranteed and assembly errors reduced during mass production. H2 cannot be too small; for example, H2 ≥ 0.02 is required to ensure that the sealing pin 150 can be assembled into the receiving groove 310 of the electrode post 300. H2 mm also cannot be too large; for example, H2 ≤ 0.2 mm is required to avoid excessive width, which would reduce the mating surface between the electrode post 300 and the sealing pin 150 and lead to welding bursts.

[0046] Figure 7 It shows Figure 5 A magnified view of region D in the middle. Further details can be found in the following diagrams. Figure 5 , Figure 6 as well as Figure 7 In some embodiments, the receiving groove 310 is a stepped hole, comprising a first hole segment 311, a second hole segment 312, and a third hole segment 313 that are sequentially continuous and have progressively decreasing diameters. The opening of the receiving groove 310 is located at one end of the first hole segment 311 away from the electrode assembly 120. The second wall 3122 is an annular stepped surface that connects the second hole segment 312 and the third hole segment 313. The hole wall of the second hole segment 312 is a third circumferential sidewall 3121. In the axial direction of the sealing pin 150, the distance between the first wall 1515 and the second wall 3122 of the sealing pin 150 is H3 mm, wherein 0.02 ≤ H3 ≤ 0.2.

[0047] The distance H3 mm between the first wall 1515 and the second wall 3122 cannot be too small. If the distance between the first wall 1515 and the second wall 3122 is too small, it is difficult to ensure that the first wall 1515 and the second wall 3122 are spaced apart and do not contact each other, especially when the outer flange 301 of the pole post is an external riveting structure, which may cause deviations in the tilt angle of the third peripheral side wall 3121 or unevenness of the second wall 3122. Furthermore, by setting the tilt angle of the second peripheral side wall 1512 and the third peripheral side wall 3121, it is ensured that the sealing nail 150 is placed in the receiving groove 310 of the pole post 300, and that the second peripheral side wall 1512 and the third peripheral side wall 3121 can contact and fit, avoiding contact between the second peripheral side wall 1512 and the third peripheral side wall 3121, which would be detrimental to the welding between the sealing nail 150 and the pole post.

[0048] The distance H3 mm between the first wall 1515 and the second wall 3122 should not be too large. If the distance H3 is too large, the contact area between the third peripheral side wall 3121 and the second peripheral side wall 1512 will be reduced, resulting in welding bursts between the sealing nail 150 and the pole post 300.

[0049] In some embodiments, it may be understood that the connecting portion 151 of the sealing pin 150 extends from the second hole segment 312 to the first hole segment 311.

[0050] In some embodiments, along the axial Z-axis of the pole post 300, the height of the first hole segment 311 is H4 mm, and the height of the second hole segment 312 is H7 mm, where 0.1 × H7 ≤ H4 ≤ 0.6 × H7. The ratio between the height H4 mm of the first hole segment 311 and the height H7 mm of the second hole segment 312 should not be too small, for example, it should be set to 0.1 × H7 ≤ H4, because the first hole segment 311 is used to absorb the welding part 400, which can prevent the welding part 400 from being higher than the upper surface of the pole post 300; the ratio between the height H4 mm of the first hole segment 311 and the height H7 mm of the second hole segment 312 should also not be too large, for example, it should be set to H4 ≤ 0.6 × H7, to avoid the third circumferential sidewall 3121 being too short, which would result in an inaccurate fit between the mating surface of the third circumferential sidewall 3121 of the pole post 300 and the second circumferential sidewall 1512 of the sealing pin 150.

[0051] See also Figure 5 and Figure 6 In some embodiments, in the axial direction of the sealing pin 150, the distance between the top surface of the body 152 and the first wall 1515 of the sealing pin 150 is the height H6 mm of the sealing pin 150, and the minimum height of the connecting portion 151 between the annular groove 153 and the first wall 1515 of the sealing pin 150 is H5 mm, wherein 0.15 × H6 ≤ H5 ≤ 0.5 × H6. Setting 0.15 × H6 ≤ H5 avoids the annular groove 153 from being too deep, thus affecting the strength of the sealing pin 150; correspondingly, setting H5 ≤ 0.5 × H6 avoids the annular groove 153 from being too shallow, making the effect of the annular groove 153 in buffering the stress concentration caused by the heat effect during welding of the sealing pin 150 to the pole post 300 insignificant. It can be understood that the ratio between H5 and H6 is the maximum proportion of the annular groove 153 in the height of the sealing pin 150.

[0052] In some embodiments, the top surface of the weld portion 400 is arched. In embodiments where the receiving groove is a stepped hole, the hole wall of the first hole segment is connected to the hole wall (third circumferential sidewall) of the second hole segment via an annular stepped surface. Along the axial direction of the sealing pin away from the electrode assembly, the highest point of the weld portion 400 is higher than the annular stepped surface. At least a portion of the weld portion 400 is formed on the annular stepped surface between the first and second hole segments to ensure that the sealing pin 150 and the electrode post 300 have sufficient thickness at the weld joint to prevent burn-through.

[0053] In the radial direction X of the pole post 300, the width of the second wall 3122 is W1 mm, where 0.3 ≤ W1 ≤ 1.0. If the width W1 mm ​​of the second wall 3122 is too small, for example, W1 < 0.3, the wall thickness of the pole post 300 becomes thinner, thus weakening the pole post strength. Furthermore, in some embodiments, in the receiving groove 310 of the pole post 300, through welding is performed at the bottom surface of the third hole section 313 to form a solder mark to weld the pole post 300 to the collector plate. If the width W1 mm ​​of the second step surface 3122 is too large, for example, W1 > 1.0, the bottom surface of the third hole section 313 becomes narrower, resulting in a narrower welding area with the collector plate, thereby reducing the welding area between the pole post 300 and the collector plate.

[0054] See also Figure 5 , Figure 6 as well as Figure 7 In some embodiments, in the radially inward direction of the pole post 300, the hole wall 3131 of the third hole section is closer to the axis G than the first sidewall 1531 of the annular groove 153 that is closest to the axis G of the pole post 300. This prevents welding slag from falling into the third hole section 313 and affecting the welding of the pole post 300 and the lower manifold.

[0055] In some embodiments, the pole post 300 includes a column portion 303 passing through the end wall of the housing, an outer flange 301, and an inner flange 302. The outer flange 301 is connected to the column portion 303 and extends outside the housing 200 in a direction opposite to the axis G of the pole post 300. The inner flange 302 is connected to the column portion 303 and extends inside the housing 200 in a direction opposite to the axis G of the pole post 300. A receiving groove 310 is provided in the column portion 303. In the radial direction X of the pole post 300, the distance between the hole wall of the first hole segment 311 and the first peripheral sidewall 1511 is W3 mm. The outer sidewall of the outer flange 301 away from the axis G of the pole post 300 is connected to the hole wall of the first hole segment 311 through a second annular connecting surface 4000. The width of the second annular connecting surface 4000 in the radial direction X of the pole post 300 is W4 mm, 0.1≤W3 / W4≤0.6. If the ratio of W3 / W4 is too small, for example, W3 / W4 < 0.1, the annular step surface between the hole wall of the first hole segment 311 and the hole wall (third circumferential side wall) of the second hole segment is too narrow and insufficient to accommodate the weld pool of the welded part 400; if the ratio is too large, for example, W3 / W4 > 0.6, the flange width of the outer flange 301 of the pole post 300 is too short, which will affect the strength of the pole post 300.

[0056] Embodiments of this application also provide a battery pack 1002, including a plurality of secondary batteries 100 as described in any one of the above claims and at least one busbar, wherein the sealing pin 150 of any one of the plurality of secondary batteries 100 is connected to the housing 200 of another secondary battery 100 via the busbar, and the battery pack 1002 may have the beneficial effects described above with respect to the secondary batteries 100.

[0057] Embodiments of this application also provide an electronic device 1000, which includes a battery pack 1002 of any of the above-mentioned components, and the electronic device 1000 may have the beneficial effects described above with respect to the secondary battery 100.

[0058] The technical solution provided in this application at least avoids the impact on welding quality caused by assembly errors between the sealing nail and the pole.

[0059] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A secondary battery characterized by comprising: include: The housing includes an end wall and side walls surrounding the end wall; Electrode assembly, housed within the housing; An electrode post having a receiving groove, the opening of which is located at one end of the electrode post away from the electrode assembly; A sealing pin is accommodated in the receiving groove. Along the direction from the opening of the receiving groove to the electrode assembly, the outer periphery of the sealing pin includes a first circumferential sidewall and a second circumferential sidewall connected in sequence. The sealing pin also includes a first wall connected to the second circumferential sidewall. The second circumferential sidewall has a first inclination angle relative to the axial direction of the sealing pin, the first inclination angle being K1°. The included angle between the first circumferential sidewall and the axial direction of the sealing pin is K3°. The receiving groove includes a third circumferential sidewall and a second wall connected to each other; along the axial direction of the sealing pin, the first wall and the second wall are opposite to and spaced apart; along the radial direction of the pole post, at least a portion of the first circumferential sidewall and the second circumferential sidewall are opposite to the third circumferential sidewall, the first circumferential sidewall is welded to the third circumferential sidewall, and the third circumferential sidewall has a second inclination angle relative to the axial direction of the pole post, the angle of the second inclination angle being K2°, where K1>K2>K3.

2. The secondary battery according to claim 1, characterized by K1 - K2 < 5; and / or, K3 = 0.

3. The secondary battery according to claim 1, characterized by The sealing pin includes a body and a connecting portion. The first peripheral sidewall and the second peripheral sidewall are the peripheral sidewalls of the connecting portion. The surface of the connecting portion facing away from the electrode assembly includes a first annular connecting surface and an annular groove. The annular groove is arranged around the body, and the annular groove and the first peripheral sidewall are connected through the first annular connecting surface. Wherein: along the radial direction of the sealing nail, the outer diameter of the first peripheral sidewall is R1 mm, the width of the first annular connecting surface is W2 mm, and 0.02≤W2 / R1≤0.

2.

4. The secondary battery according to claim 3, characterized by In the axial direction of the sealing nail, the height of the body is H6 mm, and the minimum height of the connecting part between the annular groove and the first wall is H5 mm, wherein 0.15×H6≤H5≤0.5×H6.

5. The secondary battery according to claim 1, characterized by The receiving groove is a stepped hole, comprising: a first hole segment, a second hole segment, and a third hole segment that are sequentially continuous and have progressively smaller diameters. The opening is located at the end of the first hole segment away from the electrode assembly. The second wall is an annular stepped surface that connects the second hole segment and the third hole segment. The hole wall of the second hole segment is the third peripheral sidewall. Wherein, in the axial direction of the sealing pin, the distance between the first wall and the second wall of the sealing pin is H3 mm, wherein 0.02 ≤ H3 ≤ 0.2; and / or, The height of the first peripheral sidewall in the axial direction of the sealing pin is H1 mm, wherein 0.05 ≤ H1 ≤ 0.3; and / or, Along the axial direction of the pole post, the height of the first hole section is H4 mm, and the height of the second hole section is H7 mm, wherein 0.1×H7≤H4≤0.6×H7.

6. The secondary battery according to claim 5, characterized by The pole post includes a cylindrical body, an outer flange, and an inner flange. The outer flange is connected to the cylindrical body outside the housing and extends along an axis opposite to the pole post. The inner flange is connected to the cylindrical body inside the housing and extends along an axis opposite to the pole post. The receiving groove is disposed in the cylindrical body. Wherein: in the axial direction of the pole post, the distance between the hole wall of the first hole segment and the first peripheral side wall is W3 mm, the outer side wall of the outer flange away from the axis of the pole post is connected to the hole wall of the first hole segment through a second annular connecting surface, the width of the second annular connecting surface along the radial direction of the pole post is W4 mm, and 0.1≤W3 / W4≤0.

6.

7. The secondary battery according to claim 3, characterized by Along the axial direction of the sealing pin, in the direction away from the electrode assembly, the height of the body is greater than the height of the connecting portion.

8. The secondary battery according to any one of claims 1 to 7, characterized in that, The distance from the end of the second peripheral sidewall near the electrode assembly to the third peripheral sidewall is H2 mm, where 0.02 ≤ H2 ≤ 0.

2.

9. A battery pack characterized by comprising: It includes a plurality of secondary batteries as described in any one of claims 1 to 8 and at least one busbar, wherein the sealing pin of any one of the plurality of secondary batteries is connected to the housing of another secondary battery through the busbar.

10. An electronic device, comprising: Includes the battery pack as described in claim 9.

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