Cylindrical battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and provides a cylindrical battery and a battery pack. The cylindrical battery comprises a battery shell, the battery shell comprises a shell part and a cover plate, the shell part is provided with a containing cavity, an opening end is formed in at least one end of the shell part, and the cover plate is located at the opening end; wherein the cover plate and the shell part are in welded connection to form a welding mark, at least part of the welding mark is located on the outer surface, away from the containing cavity, of the cover plate, the outer surface is perpendicular to the axial direction of the cylindrical battery, the wall thickness of the end, connected with the cover plate, of the shell part is a, the wall thickness of the end, connected with the shell part, of the cover plate is b, and a / b ranges from 0.1 to 0.8; the risk that the shell part is welded through in the welding process can be reduced, heat transfer in the welding process can also be reduced, and then the safe use performance of the cylindrical battery is improved.

Description

Technical Field

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

[0002] In the related art, the battery case of a cylindrical battery may include a cover plate and a shell member, which may be welded together to ensure the structural stability of the battery case. However, due to the structural limitations of the battery case itself, the safety performance of the battery case may be affected during the welding process of the cover plate and the shell member. Utility Model Content

[0003] The utility model provides a cylindrical battery and a battery pack to improve the use performance of the cylindrical battery.

[0004] According to a first aspect of the utility model, a cylindrical battery is provided, comprising a battery housing, the battery housing comprising a housing member and a cover plate, the housing member having a receiving chamber, at least one end of the housing member being formed with an open end, the cover plate being located at the open end;

[0005] Among them, the cover plate and the shell member are welded to form a weld mark, at least part of the weld mark is located on the outer surface of the cover plate away from the accommodating chamber, the outer surface is perpendicular to the axial direction of the cylindrical battery, the wall thickness of the end where the shell member is connected to the cover plate is a, the wall thickness of the end where the cover plate is connected to the shell member is b, and a / b is 0.1-0.8.

[0006] The cylindrical battery of the utility model embodiment includes a battery shell, and the shell member and the cover plate of the battery shell are welded and connected, thereby ensuring the connection stability of the shell member and the cover plate. The shell member has a accommodating chamber, and at least one end of the shell member is formed with an open end, and the cover plate is located at the open end. The shell member and the cover plate are welded to form a closure of the open end. The cover plate and the shell member are welded to form a weld mark, and at least part of the weld mark is located on the outer surface of the cover plate away from the accommodating chamber. Therefore, when the cover plate and the shell member are welded, welding can be performed on the top of the cover plate, thereby improving the overall assembly efficiency of the cylindrical battery, and continuous production of cylindrical battery sealing welding can be performed. The wall thickness of the end of the shell member connected to the cover plate is a, and the wall thickness of the end of the cover plate connected to the shell member is b, and a / b is 0.1-0.8, which can not only reduce the risk of the shell member being welded through during welding, but also reduce the heat transfer during welding, thereby improving the safety performance of the cylindrical battery.

[0007] According to a second aspect of the present invention, a battery pack is provided, comprising the above-mentioned cylindrical battery.

[0008] The cylindrical battery of the battery pack of the utility model embodiment includes a battery shell, and the shell member and the cover plate of the battery shell are welded and connected, thereby ensuring the connection stability of the shell member and the cover plate. The shell member has a accommodating chamber, and at least one end of the shell member is formed with an open end, and the cover plate is located at the open end. The shell member and the cover plate are welded to form a closure of the open end. The cover plate and the shell member are welded to form a weld mark, and at least part of the weld mark is located on the outer surface of the cover plate away from the accommodating chamber. Therefore, when the cover plate and the shell member are welded, welding can be performed on the top of the cover plate, thereby improving the overall assembly efficiency of the cylindrical battery, and continuous production of cylindrical battery sealing welding can be performed. The wall thickness of the end of the shell member connected to the cover plate is a, and the wall thickness of the end of the cover plate connected to the shell member is b, and a / b is 0.1-0.8, which can not only reduce the risk of the shell member being welded through during welding, but also reduce the heat transfer during welding, thereby improving the safe use performance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, related elements or components may have different arrangements as known in the art. In addition, in the drawings, the same reference numerals represent the same or similar components in each drawing. Among them:

[0010] Figure 1 is a schematic structural diagram of a battery according to a first exemplary embodiment;

[0011] Figure 2 is a schematic structural diagram of a battery according to a second exemplary embodiment;

[0012] Figure 3 is a schematic structural diagram of a battery according to a third exemplary embodiment;

[0013] Figure 4 is a schematic structural diagram of a battery cell according to a first exemplary embodiment;

[0014] Figure 5 is a schematic structural diagram of a battery cell according to a second exemplary embodiment;

[0015] Figure 6 is a schematic structural diagram of a battery cell according to a third exemplary embodiment;

[0016] Figure 7 is a schematic structural diagram of a battery pack according to an exemplary embodiment.

[0017] The following are the descriptions of the reference numerals:

[0018] 10. Battery case; 11. Case member; 111. Accommodating chamber; 112. Open end; 12. Cover plate; 121. Welding mark; 122. Outer surface; 123. Main body; 124. Extended portion; 125. First portion; 126. Second portion; 20. Battery cell; 21. Diaphragm; 22. Battery cell body; 23. First pole ear; 24. Second pole ear; 30. Pole column assembly; 40. Bottom support structure; 50. First bus bar; 60. Second bus bar. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings in the exemplary embodiments of the present disclosure to clearly and completely describe the technical solutions in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of the present disclosure.

[0020] In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; the term "and / or" includes any and all combinations of one or more associated listed items. In particular, reference to "the / the" object or "an" object is also intended to indicate one of a possible plurality of such objects.

[0021] Unless otherwise specified or explained, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0022] Further, in the description of the present disclosure, it should be understood that the directional words such as "upper", "lower", "inner", "outer" and the like described in the exemplary embodiments of the present disclosure are described at the angles shown in the accompanying drawings and should not be understood as limitations on the exemplary embodiments of the present disclosure. It should also be understood that, in the context, when it is mentioned that an element or feature is connected to another element (one or more) "upper", "lower", or "inner", "outer", it can not only be directly connected to the other (one or more) elements "upper", "lower", "inner", "outer", but also can be indirectly connected to the other (one or more) elements "upper", "lower", "inner", "outer" through an intermediate element.

[0023] An embodiment of the utility model provides a cylindrical battery, please refer to Figures 1 to 6 The cylindrical battery includes a battery shell 10, and the battery shell 10 includes a shell member 11 and a cover plate 12. The shell member 11 has a accommodating chamber 111, and at least one end of the shell member 11 is formed with an open end 112, and the cover plate 12 is located at the open end 112; wherein the cover plate 12 is welded to the shell member 11 to form a weld mark 121, and at least part of the weld mark 121 is located on an outer surface 122 of the cover plate 12 away from the accommodating chamber 111, and the outer surface 122 is perpendicular to the axial direction of the cylindrical battery, the wall thickness of the end of the shell member 11 connected to the cover plate 12 is a, and the wall thickness of the end of the cover plate 12 connected to the shell member 11 is b, and a / b is 0.1-0.8.

[0024] A cylindrical battery in one embodiment of the utility model includes a battery shell 10, wherein a shell member 11 and a cover plate 12 of the battery shell 10 are welded and connected, thereby ensuring the connection stability between the shell member 11 and the cover plate 12. The shell member 11 has a accommodating chamber 111, and at least one end of the shell member 11 is formed with an open end 112, and the cover plate 12 is located at the open end 112. The shell member 11 and the cover plate 12 are welded to form a weld mark 121, and at least part of the weld mark 121 is located on the outer surface 122 of the cover plate 12 away from the accommodating chamber 111, thereby allowing welding to be performed on the top of the cover plate 12 when welding the cover plate 12 to the shell member 11, thereby improving the overall assembly efficiency of the cylindrical battery, and enabling continuous production of cylindrical battery sealing welding. The wall thickness of the end where the shell member 11 is connected to the cover plate 12 is a, and the wall thickness of the end where the cover plate 12 is connected to the shell member 11 is b, and a / b is 0.1-0.8, which can not only reduce the risk of welding through the shell member 11 during welding, but also reduce the heat transfer during welding, thereby improving the safety performance of the cylindrical battery.

[0025] It should be noted that, combined with Figures 1 to 3 As shown, the battery housing 10 includes a housing member 11 and a cover plate 12. The housing member 11 has a accommodating chamber 111. At least one end of the housing member 11 is formed with an open end 112. The cover plate 12 is located at the open end 112, that is, the cover plate 12 forms a seal for the open end 112, thereby ensuring the sealing performance of the battery housing 10.

[0026] Combination Figure 2 and Figure 3As shown, the cover plate 12 is welded to the shell member 11 to form a weld mark 121, and at least part of the weld mark 121 is located on the outer surface 122 of the cover plate 12 away from the accommodating chamber 111, that is, here only represents that at least part of the weld mark 121 located outside the battery shell 10 is located on the outer surface 122 of the cover plate 12 away from the accommodating chamber 111, and does not include the part located inside the battery shell 10. The outer surface 122 is perpendicular to the axial direction of the cylindrical battery, that is, in the process of welding the cover plate 12 and the shell member 11, top welding is used. The welding of the cover plate 12 and the top surface of the shell member 11 improves the overall assembly efficiency of the battery, and can make the battery sealing welding continuous production. Figure 2 and Figure 3 Only a portion of the weld mark 121 is shown.

[0027] Combination Figure 1 and Figure 2 As shown, the axial direction of the cylindrical battery can be represented as X, and the axial direction of the cylindrical battery is the height direction of the cylindrical battery.

[0028] Combination Figure 2 and Figure 3 As shown, the wall thickness of the end where the shell member 11 is connected to the cover plate 12 can be expressed as a, and the wall thickness of the end where the cover plate 12 is connected to the shell member 11 can be expressed as b. The ratio of the wall thickness a at the end where the shell member 11 is connected to the cover plate 12 to the wall thickness b at the end where the cover plate 12 is connected to the shell member 11 is too small. If the shell member 11 is too thin, it is easy to cause deformation during the assembly process, affecting the subsequent grouping of the battery and the yield of the battery. In addition, the penetration welding between the cover plate 12 and the shell member 11 will produce a weld mark with a certain depth and width of fusion. If the shell member 11 is too thin, there is a risk of welding through, which may affect the battery cells inside the battery shell. The ratio of the wall thickness a at the end where the shell member 11 and the cover plate 12 are connected to the wall thickness b at the end where the cover plate 12 and the shell member 11 are connected is too large. The cover plate 12 may be squeezed by the shell member 11 and deformed greatly. The risk of deformation is relatively high, which affects the sealing performance and structural strength of the assembly of the two. In addition, the thickness of the cover plate 12 is too small, which causes the heat from welding to be quickly transferred to the battery cell, causing the risk of internal short circuit in the battery.

[0029] The ratio of the wall thickness a at the end where the shell 11 is connected to the cover 12 to the wall thickness b at the end where the cover 12 is connected to the shell 11 can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 or 0.8, etc.

[0030] In one embodiment, along the radial direction of the cylindrical battery, the molten width of the weld mark 121 located on the outer surface 122 is greater than the molten width of the weld mark 121 close to the shell member 11, that is, it can be considered that the molten width of the weld mark 121 located on the outer surface 122 is greater than the molten width of the weld mark 121 at the connection between the shell member 11 and the cover plate 12, and it can be considered that during the welding process, the welding energy is transmitted from the cover plate 12 to the shell member 11, thereby melting the cover plate 12 and the shell member 11, thereby realizing a reliable fixed connection between the cover plate 12 and the shell member 11. For example, the cover plate 12 and the shell member 11 can be welded by laser penetration welding, and the laser head is located at the outer surface 122 of the cover plate 12, thereby forming a laser penetration welding connection between the cover plate 12 and the shell member 11.

[0031] Combination Figure 1 and Figure 2 As shown, the radial direction of the cylindrical battery can be expressed as Y, that is, the direction extending from the center point of the cylindrical battery to the circumferential outer edge of the cylindrical battery.

[0032] The battery housing 10 is cut along the height direction of the battery housing 10 , so that it is convenient to measure that the weld width of the weld mark 121 located on the outer surface 122 is larger than the weld width of the weld mark 121 close to the housing member 11 .

[0033] In one embodiment, the maximum weld width of the weld mark 121 is 100 μm-1500 μm, which can ensure the connection reliability between the cover plate 12 and the shell member 11, and can also ensure the overall flow area of ​​the cover plate 12 when the cover plate 12 is used as an electrode lead-out terminal.

[0034] If the maximum weld width of the weld mark 121 is too small, the connection stability between the cover plate 12 and the shell member 11 will be reduced, and the sealing performance between the cover plate 12 and the shell member 11 will be poor, which may cause the battery to explode abnormally; and if the maximum weld width of the weld mark 121 is too large, it may cause the overall flow area of ​​the end face of the cover plate 12 to shorten, affecting the overall fast charging performance of the battery.

[0035] The maximum weld width of weld mark 121 can be 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 180μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm, 800μm, 850μm, 900μm, 950μm, 1000μm, 1100μm, 1150μm, 1200μm, 1250μm, 1300μm, 1350μm, 1400μm, 1450μm or 1500μm, etc.

[0036] In one embodiment, the wall thickness of one end where the shell member 11 is connected to the cover plate 12 is a, and a is 0.1mm-0.5mm, which can not only ensure the structural strength of the cover plate 12, but also ensure the connection strength between the shell member 11 and the cover plate 12, and also avoid the cover plate 12 being too thick and requiring a large amount of welding heat, thereby affecting the overall quality of the battery shell 10.

[0037] The wall thickness a of the end where the shell 11 is connected to the cover plate 12 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm or 0.5 mm, etc.

[0038] In one embodiment, the wall thickness of the end where the cover plate 12 is connected to the shell member 11 is b, and b is 0.3mm-2mm. On the basis of ensuring the structural strength of the shell member 11, it can also ensure that there is a reliable contact area between the cover plate 12 and the shell member 11, thereby improving the connection strength between the shell member 11 and the cover plate 12, and avoiding the risk of reducing the battery energy density due to the excessive thickness of the shell member 11.

[0039] The wall thickness b at one end of the cover plate 12 connected to the shell member 11 can be 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.2mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm or 2mm, etc.

[0040] In one embodiment, along the axial direction of the cylindrical battery, the molten pool depth of the weld mark 121 is 50 μm-2000 μm, which can not only ensure the connection stability between the shell 11 and the cover plate 12, but also avoid the problem of excessive heat dissipation during welding due to the large molten pool depth.

[0041] The depth of the molten pool of the weld mark 121 can be measured by cutting along the height direction of the battery shell 10 , and the depth of the molten pool of the weld mark 121 is its maximum depth.

[0042] If the depth of the weld pool of the weld mark 121 is too small, the shell 11 and the cover plate 12 are not firmly connected, which may cause the risk of accidental explosion. If the depth of the weld pool of the weld mark 121 is too large, the heat may be quickly transferred to the battery cell, causing the insulation failure risk such as melting of the internal insulation parts of the battery.

[0043] The molten pool depth of the weld mark 121 can be 200 μm, 210 μm, 220 μm, 250 μm, 260 μm, 270 μm, 280 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 10 ... 00μm, 1100μm, 1150μm, 1200μm, 1250μm, 1300μm, 1350μm, 1400μm, 1450μm, 1500μm, 15 50μm, 1600μm, 1650μm, 1700μm, 1750μm, 1800μm, 1850μm, 1900μm, 1950μm or 2000μm, etc.

[0044] In one embodiment, the thermal conductivity of the cover plate 12 is 10W / (m×K)-300W / (m×K). While improving the heat dissipation rate of the cover plate 12, it can avoid the thermal conductivity of the cover plate 12 being too large, and the heat of the cover plate 12 is quickly transferred to the insulating part of the battery cell, causing safety problems.

[0045] The thermal conductivity of the cover plate 12 can be 10 W / (m×K), 15 W / (m×K), 20 W / (m×K), 25 W / (m×K), 30 W / (m×K), 35 W / (m×K), 40 W / (m×K), 45 W / (m×K), 50 W / (m×K), 55 W / (m×K), 60 W / (m×K), 65 W / (m×K), 70 W / (m×K), K), 75W / (m×K), 80W / (m×K), 85W / (m×K), 90W / (m×K), 95W / (m×K), 100W / (m×K), 110W / ( m×K), 120W / (m×K), 125W / (m×K), 130W / (m×K), 135W / (m×K), 140W / (m×K), 145W / (m×K) , 150W / (m×K), 165W / (m×K), 170W / (m×K), 175W / (m×K), 180W / (m×K), 185W / (m×K), 19 0W / (m×K), 195W / (m×K), 200W / (m×K), 210W / (m×K), 220W / (m×K), 225W / (m×K), 230W / ( 250W / (m×K), 265W / (m×K), 270W / (m×K), 275W / (m×K), 280W / (m×K), 285W / (m×K), 290W / (m×K), 295W / (m×K) or 300W / (m×K), etc.

[0046] In one embodiment, Figure 2 and Figure 6 As shown, the battery further includes a battery cell 20, which is located in the accommodating chamber 111. The battery cell 20 includes a diaphragm 21, so that the diaphragm 21 forms an insulating protection for the positive electrode sheet and the negative electrode sheet.

[0047] The thickness of the diaphragm 21 is 8 μm-20 μm, which can not only prevent the insulation failure of the battery cell 20, but also prevent the diaphragm 21 from being too thick and occupying a large space inside the battery, thereby ensuring the overall energy density of the cylindrical battery.

[0048] The thickness of the diaphragm 21 can be 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm or 20μm, etc.

[0049] In one embodiment, the number of layers of the diaphragm 21 on the circumferential outer surface of the battery cell 20 is 1-5, which can not only ensure that the diaphragm 21 forms an insulating protection for the circumferential outer surface of the battery cell 20, but also avoid that too many layers of the diaphragm 21 on the circumferential outer surface of the battery cell 20 affect the heat transfer rate between the battery cell 20 and the battery casing 10, thereby ensuring the safe use performance of the cylindrical battery.

[0050] In one embodiment, Figure 4 As shown, the battery also includes a battery cell 20, which is located in the accommodating chamber 111, and the battery cell 20 includes a battery cell body 22, a first pole ear 23 and a second pole ear 24; wherein, the first pole ear 23 and the second pole ear 24 with opposite polarities extend from the same end of the battery cell body 22, thereby improving the space utilization rate of the battery casing 10, thereby improving the energy density of the battery, and the first pole ear 23 and the second pole ear 24 with opposite polarities extend from the same end of the battery cell body 22, which can increase the rate of heat transfer to the battery casing 10, increase the overall heat transfer rate of the cylindrical battery, and at the same time avoid the heat generated by welding from damaging the battery cell 20.

[0051] In one embodiment, Figure 5As shown, the battery also includes a battery cell 20, which is located in the accommodating chamber 111, and the battery cell 20 includes a battery cell body 22, a first pole ear 23 and a second pole ear 24; wherein the first pole ear 23 and the second pole ear 24 with opposite polarities extend from opposite ends of the battery cell body 22, which can not only make the electron transmission path shortest, the transmission rate fast, and increase the overall flow area of ​​the battery, but also generate less heat, thereby improving the safety performance of the battery.

[0052] In one embodiment, the first electrode tab 23 is electrically connected to the cover plate 12, so that the cover plate 12 can be used as an electrode lead-out terminal, which facilitates the subsequent grouping of cylindrical batteries and reduces the number of components used in the cylindrical batteries.

[0053] In one embodiment, Figure 1 and Figure 2 As shown, the battery also includes a pole assembly 30, which is arranged on the cover plate 12, and the second pole ear 24 is electrically connected to the pole assembly 30, so that the cover plate 12 and the pole assembly 30 can be used as two electrode lead-out terminals, and the positive and negative poles of the cylindrical battery can be led out at the same end, thereby improving the overall current transmission rate of the cylindrical battery.

[0054] The pole assembly 30 and the cover plate 12 may be insulated from each other.

[0055] In one embodiment, the minimum distance between the weld mark 121 and the pole assembly 30 is 8 mm to 20 mm, which can ensure the connection strength between the cover plate 12 and the shell 11 and the overall fast charging performance of the cylindrical battery.

[0056] If the distance between the weld mark 121 and the pole assembly 30 is too close, the vibration of the pole assembly 30 may cause the weld seal between the weld mark 121 and the pole assembly 30 to fail; if the distance between the weld mark 121 and the pole assembly 30 is too far, the current flow area of ​​the pole assembly 30 is narrow, which may affect the overall fast charging performance of the cylindrical battery.

[0057] The minimum distance between the weld mark 121 and the pole assembly 30 can be 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, 15mm, 15.5mm, 16mm, 16.5mm, 17mm, 17.5mm, 18mm, 18.5mm, 19mm or 20mm, etc.

[0058] In one embodiment, the weld mark 121 is annular, and the distance between the geometric center of the weld mark 121 and the geometric center of the cover plate 12 is ≤5 mm, thereby ensuring the connection strength between the cover plate 12 and the shell member 11, and also facilitating welding between the cover plate 12 and the shell member 11, thereby improving the manufacturing efficiency of the cylindrical battery.

[0059] The circumferential outer surface of the cover plate 12 may be circular, and the center line of the circle may pass through the geometric center of the cover plate 12. The weld mark 121 is annular, and the circumferential outer surface of the weld mark 121 may be circular, and the center line of the circle may pass through the geometric center of the weld mark 121. The distance between the geometric center of the weld mark 121 and the geometric center of the cover plate 12 may be 5 mm, 4.5 mm, 4 mm, 3.5 mm, 3 mm, 2.5 mm, 2 mm, 1.5 mm or 1 mm, etc.

[0060] It should be noted that the cover plate 12 and the shell member 11 may be welded by laser, or by resistance welding, or by ultrasonic welding, etc.

[0061] In one embodiment, the diameter of the cover plate 12 is 40 mm-82 mm, which not only facilitates the welding between the cover plate 12 and the shell member 11, ensures the connection strength between the cover plate 12 and the shell member 11, and reduces the risk of connection failure between the cover plate 12 and the shell member 11, but also ensures the overall space utilization inside the cylindrical battery, thereby improving the energy density of the cylindrical battery.

[0062] The diameter of the cover plate 12 is the diameter of the circumferential outer edge of the cover plate 12. The diameter of the cover plate 12 can be 40mm, 42mm, 43mm, 45mm, 46mm, 48mm, 50mm, 52mm, 53mm, 55mm, 56mm, 58mm, 60mm, 62mm, 63mm, 65mm, 66mm, 68mm, 70mm, 72mm, 73mm, 75mm, 76mm, 78mm, 80mm, 81mm or 82mm, etc.

[0063] In one embodiment, the shell 11 is formed with only one open end 112 , that is, the open end 112 can be sealed by a cover plate 12 , and the overall manufacturing efficiency of the cylindrical battery can also be improved.

[0064] The housing member 11 is formed with only one open end 112 , that is, the housing member 11 has a bottom wall opposite to the cover plate 12 .

[0065] In one embodiment, at least a portion of the cover plate 12 is located in the accommodating chamber 111 , which not only facilitates the installation of the cover plate 12 and improves the manufacturing efficiency of the cylindrical battery, but also facilitates the subsequent welding of the cover plate 12 and the shell member 11 .

[0066] In one embodiment, Figure 1 As shown, the cover plate 12 is overlapped on the shell member 11 , and the cover plate 12 is a flat plate with a wall thickness of b, that is, the cover plate 12 can be located entirely outside the shell member 11 , thereby increasing the internal space of the battery shell 10 .

[0067] The cover plate 12 is a flat plate, and it can be considered that the cover plate 12 can be a structure with a constant wall thickness.

[0068] In one embodiment, Figure 2 As shown, the cover plate 12 is overlapped on the shell member 11, and the cover plate 12 includes a main body portion 123 and an extension portion 124. The extension portion 124 extends from the circumferential outer edge of the main body portion 123, and the extension portion 124 is overlapped on the shell member 11. The wall thickness of the extension portion 124 is b, and the extension portion 124 is welded to the shell member 11, which not only facilitates the arrangement of the cover plate 12, so that the shell member 11 forms a positioning for the cover plate 12, thereby improving the manufacturing efficiency of the cylindrical battery, but also ensures that the cover plate 12 can have reliable structural strength.

[0069] In one embodiment, Figure 3 As shown, the entire cover plate 12 is located in the accommodating chamber 111, and the cover plate 12 includes a first portion 125 and a second portion 126. The second portion 126 extends from the side of the first portion 125 away from the accommodating chamber 111, and the wall thickness of the second portion 126 is b. The second portion 126 is welded to the shell member 11. When installing, the cover plate 12 can be positioned by the internal structure of the battery shell 10, for example, it can be positioned by the battery cell 20, thereby facilitating the installation of the cover plate 12 and further improving the installation efficiency of the cover plate 12.

[0070] It should be noted that when the cover plate 12 is arranged in the open end 112 of the shell member 11, the cover plate 12 and the top surface of the shell member 11 are welded to improve the overall assembly efficiency of the battery, and the battery sealing welding is continuously produced. The cover plate 12 and the shell member 11 need to be very close to each other to avoid damage to the internal battery cell 20 during the welding process. The ratio of the wall thickness a at the end where the shell member 11 and the cover plate 12 are connected to the wall thickness b at the end where the cover plate 12 and the shell member 11 are connected is too small. If the shell member 11 is too thin, it is easy to cause deformation of the shell member 11 during the assembly process, affecting the subsequent assembly of the battery. and the yield of the battery, and the penetration welding of the shell part 11 and the cover plate 12 will produce a weld mark with a certain depth and width of welding. If the shell part 11 is too thin, there is a risk of welding through; if the ratio of the wall thickness a at the end where the shell part 11 is connected to the cover plate 12 to the wall thickness b at the end where the cover plate 12 is connected to the shell part 11 is too large, the cover plate 12 may be squeezed by the shell part 11 and deformed greatly, with a greater risk of deformation, affecting the sealing performance and structural strength of the assembly of the two. In addition, if the thickness of the cover plate 12 is too small, the heat of welding will be quickly transferred to the battery cell 20, causing the risk of internal short circuit in the battery.

[0071] In one embodiment, the entirety of the weld mark 121 is located on the outer surface 122 , thereby effectively improving the welding efficiency between the cover plate 12 and the shell member 11 .

[0072] The entire weld mark 121 is located on the outer surface 122 , so that top welding can be used during the welding process of the cover plate 12 and the shell member 11 , thereby improving the welding efficiency of the cylindrical battery.

[0073] In some embodiments, it is not excluded that the cover plate 12 and the shell member 11 can be welded by top welding or further welded by side welding, that is, both the outer surface 122 and the side surface can have welding marks.

[0074] It should be noted that the cylindrical battery includes a battery cell and an electrolyte, which is the smallest unit capable of performing electrochemical reactions such as charging / discharging. The battery cell refers to a unit formed by winding or laminating a stacked portion, which includes a first pole piece, a separator, and a second pole piece. When the first pole piece is a positive pole piece, the second pole piece is a negative pole piece. The polarities of the first pole piece and the second pole piece can be interchanged. The first pole piece and the second pole piece are coated with an active material.

[0075] An embodiment of the utility model further provides a battery pack, comprising the above-mentioned battery.

[0076] The cylindrical battery of the battery pack of one embodiment of the utility model includes a battery shell 10, and the shell member 11 and the cover plate 12 of the battery shell 10 are welded and connected, thereby ensuring the connection stability of the shell member 11 and the cover plate 12. The shell member 11 has a accommodating chamber 111, and at least one end of the shell member 11 is formed with an open end 112. The cover plate 12 is located at the open end 112, and the shell member 11 and the cover plate 12 are welded to form a closure of the open end 112. The cover plate 12 is welded and connected to the shell member 11 to form a weld mark 121, and at least part of the weld mark 121 is located on the outer surface 122 of the cover plate 12 away from the accommodating chamber 111. Therefore, when the cover plate 12 and the shell member 11 are welded, welding can be performed on the top of the cover plate 12, thereby improving the overall assembly efficiency of the cylindrical battery, and continuous production of cylindrical battery sealing welding can be performed. The wall thickness of the end where the shell member 11 is connected to the cover plate 12 is a, and the wall thickness of the end where the cover plate 12 is connected to the shell member 11 is b. A / b is 0.1-0.8, which can not only reduce the risk of welding through the shell member 11 during welding, but also reduce the heat transfer during welding, thereby improving the safety performance of the battery pack.

[0077] In one embodiment, Figure 7 As shown, the battery pack also includes a bottom support structure 40, the cylindrical battery is arranged on the bottom support structure 40, and the cover plate 12 is arranged at the end of the shell member 11 away from the bottom support structure 40, so as to avoid the weld mark 121 between the cover plate 12 and the shell member 11 facing the bottom support structure 40, avoid vibration during the connection between the cylindrical battery and the bottom support structure 40, and further avoid the risk of connection failure between the cover plate 12 and the shell member 11.

[0078] The bottom support structure 40 may include a heat exchange structure, or the bottom support structure 40 may be the bottom of a battery box, etc., which is not limited here.

[0079] In one embodiment, the battery pack includes at least two cylindrical batteries, and the battery pack also includes a first bus bar 50 and a second bus bar 60. The first bus bar 50 is electrically connected to the battery housing 10 of the cylindrical battery, and the second bus bar 60 is electrically connected to the battery pole assembly 30, so that the cylindrical battery can be used to form an electrical connection with other batteries through the first bus bar 50 and the second bus bar 60, thereby grouping the batteries.

[0080] In one embodiment, Figure 7 As shown, the first bus bar 50 and the second bus bar 60 are located on the same side of the battery housing 10 , thereby improving the space utilization of the battery and facilitating the grouping of cylindrical batteries. The first bus bar 50 can be welded to the cover plate 12 .

[0081] The battery pack may include at least two cylindrical batteries, and the first bus bar 50 and the second bus bar 60 may realize the series connection or parallel connection of the at least two cylindrical batteries.

[0082] In one embodiment, the first bus bar 50 and the second bus bar 60 may be located on opposite sides of the battery housing 10 to accommodate the installation method and spatial arrangement of the cylindrical battery.

[0083] In one embodiment, the first busbar 50 may be welded to the battery case 10 , and the second busbar 60 may be welded to the terminal assembly 30 .

[0084] It should be noted that the first busbar 50 and the second busbar 60 are insulated. The first busbar 50 and the second busbar 60 may be insulated by an insulating member, or the first busbar 50 and the second busbar 60 may be air-insulated.

[0085] Those skilled in the art will readily come up with other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. The present disclosure is intended to cover any variation, use or adaptation of the present utility model, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and example embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0086] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from its scope. The scope of protection of the present disclosure is limited only by the appended claims.

Claims

1. A cylindrical battery, characterized in that: The battery housing (10) comprises a housing member (11) and a cover plate (12); the housing member (11) has a receiving chamber (111); at least one end of the housing member (11) is formed with an open end (112); and the cover plate (12) is located at the open end (112); The cover plate (12) and the shell member (11) are welded to form a weld mark (121); at least a portion of the weld mark (121) is located on an outer surface (122) of the cover plate (12) that faces away from the accommodating chamber (111); the outer surface (122) is perpendicular to the axial direction of the cylindrical battery; the wall thickness of the end of the shell member (11) connected to the cover plate (12) is a, and the wall thickness of the end of the cover plate (12) connected to the shell member (11) is b, and a / b is 0.1-0.

8.

2. The cylindrical battery according to claim 1, characterized in that: Along the radial direction of the cylindrical battery, the weld width of the weld mark (121) located on the outer surface (122) is greater than the weld width of the weld mark (121) close to the shell member (11).

3. The cylindrical battery according to claim 1, characterized in that: The maximum weld width of the weld mark (121) is 100 μm-1500 μm, and / or a is 0.1 mm-0.5 mm, and / or b is 0.3 mm-2 mm.

4. The cylindrical battery according to claim 1, characterized in that: Along the axial direction of the cylindrical battery, the molten pool depth of the weld mark (121) is 200 μm-2000 μm, and / or the thermal conductivity of the cover plate (12) is 10 W / (m×K)-300 W / (m×K).

5. The cylindrical battery according to claim 1, characterized in that: The battery further comprises a battery cell (20), wherein the battery cell (20) is located in the accommodating chamber (111), and the battery cell (20) comprises a diaphragm (21); Wherein, the thickness of the diaphragm (21) is 8 μm-20 μm, and / or the number of layers of the diaphragm (21) on the circumferential outer surface of the battery cell (20) is 1-5.

6. The cylindrical battery according to claim 1, characterized in that: The battery further comprises a battery cell (20), wherein the battery cell (20) is located in the accommodating chamber (111), and the battery cell (20) comprises a battery cell body (22), a first pole lug (23), and a second pole lug (24); The first pole lug (23) and the second pole lug (24) with opposite polarities extend from the same end of the battery cell body (22), or the first pole lug (23) and the second pole lug (24) with opposite polarities extend from opposite ends of the battery cell body (22).

7. The cylindrical battery according to claim 6, characterized in that: The first electrode tab (23) is electrically connected to the cover plate (12).

8. The cylindrical battery according to claim 7, characterized in that: The battery further comprises a pole assembly (30), wherein the pole assembly (30) is arranged on the cover plate (12), and the second pole lug (24) is electrically connected to the pole assembly (30).

9. The cylindrical battery according to claim 8, characterized in that: The minimum distance between the weld mark (121) and the pole assembly (30) is 8 mm to 20 mm.

10. The cylindrical battery according to any one of claims 1 to 9, characterized in that: The weld mark (121) is annular, and the distance between the geometric center of the weld mark (121) and the geometric center of the cover plate (12) is ≤5 mm.

11. The cylindrical battery according to any one of claims 1 to 9, characterized in that: The diameter of the cover plate (12) is 40 mm-82 mm, and / or the shell member (11) is formed with only one opening end (112), and / or at least a portion of the cover plate (12) is located in the accommodating chamber (111).

12. The cylindrical battery according to any one of claims 1 to 9, characterized in that: The cover plate (12) is overlapped on the shell member (11), the cover plate (12) is a flat plate, and the wall thickness of the flat plate is b; Alternatively, the cover plate (12) is overlapped on the shell member (11), the cover plate (12) comprises a main body portion (123) and an extension portion (124), the extension portion (124) extends from a circumferential outer edge of the main body portion (123), the extension portion (124) is overlapped on the shell member (11), the wall thickness of the extension portion (124) is b, and the extension portion (124) is welded to the shell member (11); Alternatively, the entire cover plate (12) is located within the accommodating chamber (111), the cover plate (12) comprises a first portion (125) and a second portion (126), the second portion (126) extends from a side of the first portion (125) away from the accommodating chamber (111), the wall thickness of the second portion (126) is b, and the second portion (126) is welded to the shell member (11).

13. The cylindrical battery according to any one of claims 1 to 9, characterized in that: The entirety of the weld mark (121) is located on the outer surface (122).

14. A battery pack, characterized in that: The battery pack comprises a cylindrical battery as claimed in any one of claims 1 to 13, wherein the battery pack further comprises a bottom support structure (40), the cylindrical battery is arranged on the bottom support structure (40), and the cover plate (12) is arranged at an end of the shell member (11) facing away from the bottom support structure (40).

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