Adapter piece and cylindrical battery

Abstract

According to the adapter piece and the cylindrical battery, the adapter piece comprises the tab welding part and the welding boss, the height difference exists between the bottom face of the welding boss and the top face of the tab welding part in the height direction of the welding boss, it can be guaranteed that the height of the welding boss is large in the height direction of the welding boss, and the welding quality of the cylindrical battery is improved. When the welding bosses and the pole columns are actually welded, the higher welding bosses ensure that the welding bosses can be tightly combined with the pole columns, and the welding effect is ensured; the elastic buffer part is positioned in the accommodating hole and is connected with the tab welding part and the welding boss, and the elastic buffer part is configured to deform to absorb extrusion force when being extruded, so that after welding, when the welding boss with higher height extrudes the tab, the elastic buffer part deforms under the action of the extrusion force to absorb the extrusion force, and the welding quality of the tab is improved. Therefore, the welding boss does not cause overvoltage to the tab, the tab and the electrode assembly do not deform, and the safety of the battery is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a switching piece and a cylindrical battery. BACKGROUND

[0002] In actual assembly of the cylindrical battery, the shell is first connected with the pole in an insulating manner, then the two ends of the electrode assembly are welded with the positive switching piece and the negative switching piece respectively to form an integral body, the integral body is loaded into the shell, the convex bump at the center position of the positive switching piece is in contact with the part of the pole extending into the shell, and then the two are laser welded to realize welding of the shell, the pole, the positive switching piece, the electrode assembly and the negative switching piece. However, this way may cause virtual welding or overpressure of the electrode assembly caused by the positive switching piece due to improper size, thereby affecting the performance of the battery. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the present application aims to provide a switching piece and a cylindrical battery to solve or partially solve the problems in the background art.

[0004] To achieve the above purpose, the present application provides a switching piece for a cylindrical battery, comprising:

[0005] a tab welding portion having an accommodating hole;

[0006] a welding boss located in the accommodating hole and used for connecting with the pole of the battery, wherein a height difference exists between the bottom surface of the welding boss and the top surface of the tab welding portion in the height direction of the welding boss, the bottom surface is the surface away from the pole, and the top surface is the surface close to the pole;

[0007] a resilient buffer portion located in the accommodating hole and connected with the tab welding portion and the welding boss, the resilient buffer portion is configured to deform to absorb the extrusion force when being extruded.

[0008] Optionally, the resilient buffer portion is arranged in a first direction, and the first direction is from the welding boss to the tab welding portion.

[0009] Optionally, the resilient buffer portion comprises a first connecting portion and a protruding portion, the first connecting portion is connected with the bottom surface of the welding boss, one end of the protruding portion is connected with the first connecting portion, and the other end of the protruding portion is connected with the top surface of the tab welding portion, and the protruding portion is an arc-shaped structure protruding towards the welding boss.

[0010] Optionally, the ratio of the size of the orthographic projection of the protruding portion in the first direction to the size of the orthographic projection of the resilient buffer portion in the first direction is 1:10-3:10.

[0011] Optionally, the first connecting portion comprises a first sub-portion and a second sub-portion, the first sub-portion is connected to the bottom surface of the welding boss, one end of the second sub-portion is connected to the first sub-portion, and the other end of the second sub-portion is connected to the protruding portion, the first sub-portion is arranged obliquely, and the second sub-portion is located in the same plane as the tab welding portion.

[0012] Optionally, the elastic buffer portion comprises a weak portion and a second connecting portion, the weak portion is connected to the bottom surface of the welding boss, one end of the second connecting portion is connected to the weak portion, and the other end of the second connecting portion is connected to the top surface of the tab welding portion, the thickness of the weak portion is less than the thickness of the second connecting portion, and the thickness direction is perpendicular to the first direction.

[0013] Optionally, the ratio of the size of the orthographic projection of the weak portion in the first direction to the size of the orthographic projection of the elastic buffer portion in the first direction is 1:10-3:10.

[0014] Optionally, a plurality of elastic buffer portions are provided, the plurality of elastic buffer portions are arranged at intervals along the circumferential direction of the accommodating hole, a buffer gap is provided between adjacent two elastic buffer portions, a plurality of weight-reducing holes are arranged at intervals on the tab welding portion, and the plurality of weight-reducing holes correspond one-to-one to the plurality of elastic buffer portions.

[0015] In the radial direction of the accommodating hole, the weight-reducing hole is arranged on the side of the buffer gap away from the welding boss.

[0016] Alternatively, the tab welding portion extends into the buffer gap, and in the radial direction of the accommodating hole, the weight-reducing hole is arranged on the side of the elastic buffer portion away from the welding boss.

[0017] The second aspect of the present application provides a cylindrical battery, comprising the adapter tab, the pole and the shell of any one of the above-mentioned first aspect, the shell is provided with a pole hole, the pole is arranged in the pole hole and is in sealed connection with the shell, the pole comprises an inner connecting portion, and the inner connecting portion is welded to the welding boss of the adapter tab after penetrating through the pole hole.

[0018] Optionally, the elastic buffer portion comprises a first connecting portion and a protruding portion, the first connecting portion is connected to the bottom surface of the welding boss, one end of the protruding portion is connected to the first connecting portion, and the other end of the protruding portion is connected to the top surface of the tab welding portion, the protruding portion protrudes towards the welding boss, and in the radial direction of the cylindrical battery, the protruding portion is located on the side of the inner connecting portion away from the welding boss.

[0019] As can be seen from the above, the adapter piece and the cylindrical battery provided by the application include a tab welding portion and a welding boss, the tab welding portion is provided with a receiving hole, the welding boss is located in the receiving hole, and a height difference exists between the bottom surface of the welding boss and the top surface of the tab welding portion in the height direction of the welding boss. In this way, the height of the welding boss is higher in the height direction of the welding boss, and the higher welding boss ensures that the welding boss can be closely combined with the pole column during actual welding of the welding boss and the pole column, thereby ensuring the welding effect. In addition, the elastic buffer portion is located in the receiving hole and connected with the tab welding portion and the welding boss, and the elastic buffer portion is configured to deform to absorb the extrusion force when being extruded. In this way, after welding, when the welding boss with a higher height extrudes the tab, the elastic buffer portion deforms under the action of the extrusion force and then absorbs the extrusion force. In this way, the extrusion of the welding boss on the tab can be reduced or even eliminated, thereby ensuring that the welding boss will not cause overpressure to the tab, and the tab and the electrode assembly will not be deformed, thereby improving the safety of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A first structure schematic diagram of the adapter piece of the embodiment of the present application is shown;

[0022] Figure 2 A second structure schematic diagram of the adapter piece of the embodiment of the present application is shown; Figure 1 A partial enlarged schematic diagram of W in the above is shown;

[0023] Figure 3 A third structure schematic diagram of the adapter piece of the embodiment of the present application is shown;

[0024] Figure 4 A fourth structure schematic diagram of the adapter piece of the embodiment of the present application is shown; Figure 3 A partial enlarged schematic diagram of Q in the above is shown;

[0025] Figure 5 A fifth structure schematic diagram of the adapter piece of the embodiment of the present application is shown;

[0026] Figure 6 A front view of the cylindrical battery of the embodiment of the present application is shown;

[0027] Figure 7 A cross-sectional view of the cylindrical battery of the embodiment of the present application in the A-A direction is shown;

[0028] Figure 8 A cross-sectional view of the cylindrical battery of the embodiment of the present application in the B-B direction is shown;Figure 7 A cross-sectional view of the middle R.

[0029] In the figure: 1, adapter piece; 11, tab welding part; 111, accommodating hole; 112, weight-reducing hole; 12, welding boss; 13, elastic buffer part; 131, weak part; 132, second connecting part; 133, first connecting part; 1331, first sub-part; 1332, second sub-part; 134, protruding part; 14, buffer gap; 2, pole post; 3, shell; 4, electrode assembly; 5, sealing ring. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to specific embodiments and the accompanying drawings.

[0031] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those with ordinary skills in the field to which the present application belongs. The terms "first", "second" and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the components or objects listed before the terms encompass the components or objects listed after the terms and their equivalents, without excluding other components or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0032] The lithium ion battery can be in the shape of a cylinder, a flat body, a cuboid or other shapes. The current battery generally includes a shell and an electrode assembly accommodated in the shell, and an electrolyte is filled in the shell. The electrode assembly is mainly formed by laminating or winding a first electrode sheet and a second electrode sheet with opposite polarities, and generally a separator is arranged between the first electrode sheet and the second electrode sheet. The parts of the first electrode sheet and the second electrode sheet coated with active material constitute the main body of the electrode assembly, and the parts of the first electrode sheet and the second electrode sheet not coated with active material each constitute a first tab and a second tab. In the lithium ion battery, the first electrode sheet can be a positive electrode sheet including a positive electrode current collector and positive electrode active material layers arranged on both sides of the positive electrode current collector, the material of the positive electrode current collector can be, for example, aluminum, and the positive electrode active material can be, for example, lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc.; the second electrode sheet can be a negative electrode sheet including a negative electrode current collector and negative electrode active material layers arranged on both sides of the negative electrode current collector, the material of the negative electrode current collector can be, for example, copper, and the negative electrode active material can be, for example, graphite or silicon, etc.

[0033] The first and second tabs can be located at one end of the main body or at two ends of the main body respectively. During the charging and discharging process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0034] For a cylindrical battery, the conventional design is that the first and second tabs are located at two ends of the battery respectively. Taking the first tab as the positive tab and the second tab as the negative tab as an example, the positive tab is connected with the positive adapter tab, and the negative tab is connected with the negative adapter tab.

[0035] In actual assembly, the shell is usually first connected with the pole in an insulating manner, and then the two ends of the electrode assembly are welded with the positive adapter tab and the negative adapter tab to form an integral body, the integral body is loaded into the shell, the convex bump at the center position of the positive adapter tab is in contact with the part of the pole extending into the shell, and then laser welding is performed on the two to realize welding of the shell, the pole, the positive adapter tab, the electrode assembly and the negative adapter tab.

[0036] After the integral body formed by the electrode assembly, the positive adapter tab and the negative adapter tab is loaded into the shell, two situations are prone to occur: one is that the height of the convex bump at the center position of the positive adapter tab is not enough, so that there is a gap between the convex bump and the pole, which is easy to cause virtual welding during subsequent laser welding; the other is that the height of the convex bump at the center position of the positive adapter tab is relatively high, the convex bump can be in close contact with the pole, and the welding effect is good, but since the height of the convex bump is relatively high, after welding, the relatively high convex bump will have a relatively large extrusion effect on the electrode assembly below, causing overpressure to the electrode assembly, resulting in the electrode assembly being concave downward, which may on the one hand cause the positive plate and the negative plate to contact to cause internal short circuit, and on the other hand may cause the active material layer on the positive plate or the negative plate to fall off.

[0037] If the above two situations are to be avoided, the height of the convex bump at the center position of the positive adapter tab needs to be strictly controlled, which greatly increases the manufacturing difficulty of the positive adapter tab and the battery, resulting in a low product yield.

[0038] Therefore, it is urgent to provide a positive adapter tab and a battery which can ensure that the convex bump of the positive adapter tab can be effectively welded with the pole, without causing overpressure to the electrode assembly, and without greatly increasing the manufacturing difficulty.

[0039] Based on this, the application provides an adapter tab for a cylindrical battery.

[0040] Figure 1 A first structure schematic diagram of the adapter tab of the embodiment of the application is shown, Figure 2 A second structure schematic diagram of the adapter tab of the embodiment of the application is shown, Figure 1 A local enlarged schematic diagram of W in the second structure schematic diagram of the adapter tab of the embodiment of the application is shown.

[0041] Referring to Figure 1and Figure 2 The adapter tab 1 for cylindrical batteries comprises:

[0042] The tab welding portion 11 is provided with a receiving hole 111;

[0043] The welding boss 12 is located in the receiving hole 111 and is used to connect with the pole of the battery. In the height direction of the welding boss 12, there is a height difference between the bottom surface of the welding boss 12 and the top surface of the tab welding portion 11. The bottom surface is the surface away from the pole 2, and the top surface is the surface close to the pole 2.

[0044] The elastic buffer portion 13 is located in the receiving hole 111 and is connected with the tab welding portion 11 and the welding boss 12. The elastic buffer portion 13 is configured to deform to absorb the extrusion force when being extruded.

[0045] In the cylindrical battery, in order to better cooperate and install with the electrode assembly of the cylindrical battery, the adapter tab 1 for cylindrical batteries is usually also circular.

[0046] The adapter tab 1 comprises the tab welding portion 11 and the welding boss 12. The bottom surface of the tab welding portion 11 is used to connect with the tab of the electrode assembly, and the top surface of the welding boss 12 is used to connect with the pole of the cylindrical battery. In this way, the adapter tab 1 connects the electrode assembly and the pole.

[0047] The receiving hole 111 is provided in the center position of the tab welding portion 11, and the welding boss 12 is located in the receiving hole 111. In this way, the welding boss 12 is located in the center position, and the tab welding portion 11 is arranged around the outer periphery of the welding boss 12.

[0048] In the height direction of the welding boss 12, there is a height difference between the bottom surface of the welding boss 12 and the top surface of the tab welding portion 11. This means that there are two positional relationships between the bottom surface of the welding boss 12 and the top surface of the tab welding portion 11:

[0049] Positional relationship one: the bottom surface of the welding boss 12 is higher than the top surface of the tab welding portion 11, that is, the bottom surface of the welding boss 12 is closer to the pole of the battery, and the top surface of the tab welding portion 11 is located on the side of the bottom surface of the welding boss 12 away from the pole. In this case, in the height direction of the welding boss 12, both the top surface and the bottom surface of the welding boss 12 are higher than the top surface of the tab welding portion 11. In this way, the welding boss 12 is arranged to protrude from the top surface of the tab welding portion 11 as a whole, and the height of the welding boss 12 is relatively high. When actually welding the welding boss 12 and the pole, the relatively high welding boss 12 ensures that the welding boss 12 can be closely combined with the pole, guarantees the welding effect, and avoids the situation that the welding boss 12 cannot be closely combined with the pole due to insufficient height of the welding boss 12, thereby causing a virtual welding situation when welding the welding boss 12 and the pole.

[0050] Position relationship two: the bottom surface of the welding boss 12 is lower than the top surface of the tab welding portion 11, that is, the top surface of the tab welding portion 11 is arranged closer to the pole of the battery, and the bottom surface of the welding boss 12 is located on the side of the top surface of the tab welding portion 11 away from the pole. In this case, it is necessary to ensure that the top surface of the welding boss 12 is higher than the top surface of the tab welding portion 11, that is, the top surface of the welding boss 12 is arranged closer to the pole of the battery, and the top surface of the tab welding portion 11 is located on the side of the top surface of the welding boss 12 away from the pole, so that the top surface of the tab welding portion 11 is arranged protruding from the top surface of the welding boss 12, which can ensure that the top surface of the welding boss 12 can be effectively welded with the pole, ensure the welding effect, and avoid the situation that the welding boss 12 cannot be closely attached to the pole due to insufficient height of the welding boss 12, thereby causing a virtual welding situation when the welding boss 12 is welded with the pole.

[0051] In order to avoid overpressure of the tab caused by the welding boss 12 with high height after welding, in the present application, the adapter sheet 1 further comprises an elastic buffer portion 13, which is located in the accommodation hole 111 and connected with the tab welding portion 11 and the welding boss 12. Thus, the elastic buffer portion 13 acts as a connecting piece between the welding boss 12 and the tab welding portion 11. The elastic buffer portion 13 is configured to deform to absorb the extrusion force when being extruded. Thus, after welding, when the welding boss 12 with high height extrudes the tab, the elastic buffer portion 13 deforms under the action of the extrusion force and absorbs the extrusion force, so that the extrusion of the welding boss 12 on the tab can be reduced or even eliminated, thereby ensuring that the welding boss 12 will not cause overpressure to the tab, and the tab and the electrode assembly will not be deformed, thereby improving the safety of the battery.

[0052] In some embodiments, continuing to refer to Figure 1 As shown, the elastic buffer portion 13 is arranged in an inclined manner along a first direction, which is the direction from the welding boss 12 to the tab welding portion 11 (i.e. the direction shown in M in FIG. 12). Figure 1

[0053] Specifically, compared with horizontal arrangement or vertical arrangement, the elastic buffer portion 13 arranged in an inclined manner is more likely to deform when being extruded, so that the elastic buffer portion 13 arranged in an inclined manner has better deformation ability. Thus, the elastic buffer portion 13 can quickly deform to absorb the extrusion force when being extruded, thereby protecting the tab and the electrode assembly from being deformed due to excessive extrusion.

[0054] In some embodiments, continuing to refer to Figure 1 and Figure 2 ​As shown, the elastic buffer part 13 includes a first connecting part 133 connected with the bottom surface of the welding boss 12 and a protruding part 134, one end of which is connected with the first connecting part 133 and the other end of which is connected with the top surface of the tab welding part 11, and the protruding part 134 is in an arc structure protruding towards the welding boss 12.

[0055] Specifically, the protruding part 134 is in an arc structure protruding towards the welding boss 12, on one hand, the arc structure has good deformation ability, and when subjected to extrusion force, the arc structure can quickly deform to absorb the extrusion force; on the other hand, the protruding part 134 protrudes towards the welding boss 12, so that the setting of the protruding part 134 does not affect the welding of the tab welding part 11 and the tab.

[0056] The protruding part 134 is connected with the top surface of the tab welding part 11, that is, the protruding part 134 is arranged close to the tab welding part 11, on one hand, the area close to the tab welding part 11 is large, facilitating the molding of the protruding part 134; on the other hand, the protruding part 134 is arranged close to the tab welding part 11, which can better absorb the extrusion force about to reach the tab welding part 11, so as to better protect the tab welding part 11 and avoid the extrusion force reaching the tab welding part 11 being too large to extrude the tab.

[0057] In specific implementation, when the welding boss 12 generates large extrusion force to the electrode assembly, the protruding part 134 will deform along the radial direction of the adapter sheet 1 to absorb the extrusion force, thereby avoiding overpressure of the welding boss 12 to the electrode assembly.

[0058] In some embodiments, the ratio of the size of the orthographic projection of the protruding part 134 in the first direction to the size of the orthographic projection of the elastic buffer part 13 in the first direction is 1:10-3:10.

[0059] Specifically, when the ratio of the size of the orthographic projection of the protruding part 134 in the first direction to the size of the orthographic projection of the elastic buffer part 13 in the first direction is 1:10-3:10, the size of the protruding part 134 is appropriate, which can not only ensure that the deformation ability of the protruding part 134 is sufficient to absorb the extrusion force generated by the welding boss 12 to the electrode assembly, but also ensure the rigidity and structural stability of the elastic buffer part 13.

[0060] When the ratio of the size of the orthographic projection of the protruding part 134 in the first direction to the size of the orthographic projection of the elastic buffer part 13 in the first direction is less than 1:10, the size of the protruding part 134 is too small, and its deformation ability is small, which cannot effectively absorb the extrusion force generated by the welding boss 12 to the electrode assembly, so that the welding boss 12 will also cause overpressure to the electrode assembly.

[0061] When the ratio of the size of the projection of the protruding part 134 in the first direction to the size of the projection of the elastic buffer part 13 in the first direction is greater than 3:10, the size of the protruding part 134 is too large, although it has sufficient deformation ability to absorb the extrusion force generated by the welding boss 12 to the electrode assembly, but it may cause insufficient rigidity and structural stability of the elastic buffer part 13, which is not conducive to actual use.

[0062] In some embodiments, the first connecting part 133 includes a first sub-part 1331 connected with the bottom surface of the welding boss 12 and a second sub-part 1332, one end of which is connected with the first sub-part 1331 and the other end of which is connected with the protruding part 134, the first sub-part 1331 is inclinedly arranged, and the second sub-part 1332 is located in the same plane as the tab welding part 11.

[0063] Specifically, the first sub-part 1331 is inclined along the first direction, so that the first sub-part 1331 also has a certain deformation ability to absorb part of the extrusion force, and the inclinedly arranged first sub-part 1331 facilitates the connection of the elastic buffer part 13 with the welding boss and the tab welding part 11.

[0064] The second sub-part 1332 is horizontally arranged and located in the same plane as the tab welding part 11, so that the second sub-part 1332 can also be used together with the tab welding part 11 to connect with the tab of the electrode assembly, thereby increasing the area of the tab welding area of the adapter sheet 1, i.e. increasing the number of tab welding circles in the cylindrical battery, shortening the current path on the electrode assembly, and further reducing the internal resistance of the electrode assembly.

[0065] In this application, the elastic buffer part 13 includes the first sub-part 1331, the second sub-part 1332 and the protruding part 134 arranged in sequence, the first sub-part 1331 serves to connect and partially absorb the extrusion force, the second sub-part 1332 serves to increase the tab welding area of the adapter sheet 1 and further reduce the internal resistance, and the protruding part 134 serves to absorb most of the extrusion force, so that the cooperation of the first sub-part 1331, the second sub-part 1332 and the protruding part 134 can not only ensure that the elastic buffer part 13 can absorb the extrusion force caused by the welding boss to protect the electrode assembly and avoid overpressure of the electrode assembly, but also ensure the rigidity and connection stability of the elastic buffer part 13, and further increase the tab welding area of the adapter sheet 1 and reduce the internal resistance.

[0066] Figure 3 A second structural schematic diagram of the adapter sheet 1 of the embodiment of the application is shown, Figure 4 A third structural schematic diagram of the adapter sheet 1 of the embodiment of the application is shown, Figure 3 A partial enlarged schematic view of Q in the third structural schematic diagram of the adapter sheet 1 of the embodiment of the application is shown.

[0067] In some embodiments, referring toFigure 3 and Figure 4 As shown in FIG. 13, the elastic buffer 13 includes a weak portion 131 and a second connecting portion 132, the weak portion 131 is connected with the bottom surface of the welding boss 12, one end of the second connecting portion 132 is connected with the weak portion 131, the other end of the second connecting portion 132 is connected with the top surface of the tab welding portion 11, the thickness of the weak portion 131 is less than the thickness of the second connecting portion 132, and the thickness direction (i.e. the direction shown by H in FIG. 13) is perpendicular to the first direction (i.e. the direction shown by M in FIG. 13). Figure 4 Figure 4

[0068] Specifically, the thickness of the weak portion 131 is less than the thickness of the second connecting portion 132, so that the weak portion 131 has a smaller rigidity and is easy to deform, and the second connecting portion 132 has a larger rigidity and is not easy to deform. When being pressed, the weak portion 131 deforms to absorb the pressing force, so as to ensure that the welding boss 12 does not cause overpressure to the electrode assembly; at the same time, the second connecting portion 132 does not deform, so as to ensure the rigidity and structural stability of the elastic buffer 13.

[0069] The weak portion 131 is connected with the bottom surface of the welding boss 12, i.e. the weak portion 131 is arranged close to the welding boss 12, so that the larger pressing force applied by the welding boss 12 can make the weak portion 131 quickly deform to absorb the pressing force.

[0070] In some embodiments, the ratio of the size of the orthographic projection of the weak portion 131 in the first direction to the size of the orthographic projection of the elastic buffer 13 in the first direction is 1:10-3:10.

[0071] Specifically, when the ratio of the size of the orthographic projection of the weak portion 131 in the first direction to the size of the orthographic projection of the elastic buffer 13 in the first direction is 1:10-3:10, the size of the weak portion 131 is appropriate, which can ensure that the deformation capacity of the weak portion 131 is sufficient to absorb the higher pressing force generated by the welding boss 12 to the electrode assembly, and also ensure the rigidity and structural stability of the elastic buffer 13.

[0072] When the ratio of the size of the orthographic projection of the weak portion 131 in the first direction to the size of the orthographic projection of the elastic buffer 13 in the first direction is less than 1:10, the size of the weak portion 131 is too small, and its deformation capacity is small, which cannot effectively absorb the higher pressing force generated by the welding boss 12 to the electrode assembly, so that the welding boss 12 will also cause overpressure to the electrode assembly.

[0073] ​​When the ratio of the size of the orthographic projection of the weak portion 131 in the first direction to the size of the orthographic projection of the elastic buffer portion 13 in the first direction is greater than 3:10, the size of the weak portion 131 is too large, although it has sufficient deformation capacity to absorb the extrusion force generated by the higher welding boss 12 to the electrode assembly, but it may cause insufficient rigidity and structural stability of the elastic buffer portion 13, which is not conducive to actual use.

[0074] Figure 5 A third structural schematic diagram of the adapter piece 1 of the embodiment of the application is shown.

[0075] In some embodiments, referring to Figure 1 and Figure 5 , the elastic buffer portion 13 is provided in plurality, the plurality of elastic buffer portions 13 are arranged at intervals along the circumferential direction of the accommodating hole 111, a buffer gap 14 is provided between the adjacent two elastic buffer portions 13, and a plurality of weight reduction holes 112 are arranged at intervals on the tab welding portion 11, the plurality of weight reduction holes 112 corresponding to the plurality of elastic buffer portions 13 one by one;

[0076] Among them, in the radial direction of the accommodating hole 111 (i.e. Figure 1 and Figure 5 , the direction shown by E), the weight reduction hole 112 is arranged on the side of the buffer gap 14 away from the welding boss 12;

[0077] Or, the tab welding portion 11 extends into the buffer gap 14, and in the radial direction of the accommodating hole 111, the weight reduction hole 112 is arranged on the side of the elastic buffer portion 13 away from the welding boss 12.

[0078] Specifically, the weight reduction hole 112 can reduce the weight of the adapter piece 1 on the one hand, and on the other hand, it is also convenient for the gas generated by the electrode assembly to be discharged from the weight reduction hole 112.

[0079] The arrangement position of the weight reduction hole 112 and the elastic buffer portion 13 can have two different cases:

[0080] Case one: referring to Figure 5 , a buffer gap 14 is provided between the adjacent two elastic buffer portions 13, and in the radial direction of the accommodating hole 111 (i.e. Figure 5 , the direction shown by E), the weight reduction hole 112 is arranged on the side of the corresponding buffer gap 14 away from the welding boss 12, so that in the specific implementation, the current can flow along the radial direction, directly from the electrode assembly to the elastic buffer portion 13 and then to the pole, which can reduce the current flow path from the electrode assembly to the pole and reduce the internal resistance between the electrode assembly and the pole.

[0081] Case two: referring to Figure 1 , in the radial direction of the accommodating hole 111 (i.e. Figure 1The weight-reducing hole 112 is arranged on the side of the corresponding elastic buffer portion 13 away from the welding boss 12 in the direction indicated by arrow R in FIG. 6, and the tab welding portion 11 can extend into the buffer gap 14 between the two adjacent elastic buffer portions 13. In this case, the area of the tab welding portion 11 is larger than that in the case shown in FIG. 5, and the area of the welding between the adapter tab 1 and the tab is increased, i.e., the number of turns of the tab welding in the cylindrical battery is increased, the current path on the electrode assembly is shortened, and the internal resistance of the electrode assembly is reduced.

[0082] In the present application, the weight-reducing hole 112 can be arranged at different positions to meet different actual requirements.

[0083] Figure 6 FIG. 1 shows a front view of a cylindrical battery according to an embodiment of the present application, Figure 7 FIG. 2 shows a cross-sectional view of the cylindrical battery according to the embodiment of the present application in the direction indicated by arrow A-A, Figure 8 FIG. 3 shows a cross-sectional view of the cylindrical battery according to the embodiment of the present application in the direction indicated by arrow R-R, Figure 7 FIG. 4 shows a cross-sectional view of the cylindrical battery according to the embodiment of the present application in the direction indicated by arrow R.

[0084] Referring to FIG. 1, Figure 6 , Figure 7 and Figure 8 FIG. 6 shows a cylindrical battery according to another embodiment of the present application, which comprises the adapter tab 1, the tab post 2, and the shell 3 according to any of the embodiments described above. The shell 3 is provided with a tab post hole, the tab post 2 is arranged in the tab post hole and is in sealing connection with the shell 3. The tab post 2 comprises an inner connecting portion, which is welded to the welding boss 12 of the adapter tab 1 after passing through the tab post hole.

[0085] Specifically, the elastic buffer portion 13 comprises a first connecting portion 133 and a protruding portion 134. The first connecting portion 133 is connected to the bottom surface of the welding boss 12, one end of the protruding portion 134 is connected to the first connecting portion 133, the other end of the protruding portion 134 is connected to the top surface of the tab welding portion 11, and the protruding portion 134 protrudes towards the welding boss 12.

[0086] In the radial direction of the cylindrical battery (i.e., the direction indicated by arrow X in FIG. 6), the protruding portion 134 is located on the side of the inner connecting portion away from the welding boss 12. In this way, the arrangement of the protruding portion 134 does not interfere with the inner connecting portion, and does not affect the assembly of the adapter tab 1 and the tab post 2. Figure 8 Further, a plurality of protruding portions 134 are arranged along the circumference of an inscribed circle having a diameter smaller than the outer diameter of the inner connecting portion, so as to ensure that the arrangement of the protruding portions 134 does not interfere with the inner connecting portion, and does not affect the assembly of the adapter tab 1 and the tab post 2.

[0087]

[0088] ​The cylindrical battery of the present application, due to the elastic buffer part 13 arranged in the adapter piece 1, the elastic buffer part 13 is configured to deform to absorb the extrusion force when being extruded, thus, after welding, when the high welding boss 12 extrudes the tab, the elastic buffer part 13 deforms under the action of the extrusion force and further absorbs the extrusion force, thus the extrusion of the welding boss 12 to the tab can be reduced or even eliminated, and further ensure that the welding boss 12 will not cause overpressure to the tab, and the tab and the electrode assembly 4 will not be deformed, and the safety of the battery is improved, therefore, the higher welding boss 12 can be arranged in the present application, and the higher welding boss 12 ensures that the welding boss 12 can be closely combined with the pole 2, and the welding effect is ensured.

[0089] It should be understood by those of ordinary skill in the art that the above discussion of any embodiment is merely exemplary and is not intended to suggest the scope of the present application (including claims) is limited to these examples; under the idea of the present application, the above embodiments or technical features in different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as above, which are not provided in details for the sake of brevity.

[0090] Embodiments of the present application are intended to cover all such alternatives, modifications and variations as fall within the broad scope of the appended claims. Accordingly, any one of the above-described and other examples of the present application can be combined with any other example, feature, aspect, or combination of other examples, features, and aspects to create additional examples within the scope of the present application. Therefore, the above description should not be construed as limiting, but merely as illustrative of the present application.

Claims

1. A tab for a cylindrical battery, characterized by The application relates to a connecting piece for a battery, which comprises: a tab welding portion with a receiving hole; a welding boss in the receiving hole for connecting with a pole of the battery, wherein the height difference between the bottom surface of the welding boss and the top surface of the tab welding portion is in the height direction of the welding boss, the bottom surface is the surface far away from the pole, and the top surface is the surface close to the pole; an elastic buffer portion in the receiving hole and connected with the tab welding portion and the welding boss, and the elastic buffer portion is configured to deform to absorb the extrusion force when being extruded.

2. The adapter plate of claim 1, wherein, The elastic buffer portion is arranged in a first direction, which is the direction from the welding boss to the tab welding portion.

3. The adapter plate of claim 2, wherein, The elastic buffer portion comprises a first connecting portion connected with the bottom surface of the welding boss and a convex portion, one end of the convex portion is connected with the first connecting portion, and the other end of the convex portion is connected with the top surface of the tab welding portion, and the convex portion is an arc structure protruding towards the welding boss.

4. The adapter plate of claim 3, wherein, The ratio of the size of the convex portion in the first direction to the size of the elastic buffer portion in the first direction is 1:10-3:

10.

5. The adapter plate of claim 3, wherein, The first connecting portion comprises a first sub-portion connected with the bottom surface of the welding boss and a second sub-portion, one end of the second sub-portion is connected with the first sub-portion, and the other end of the second sub-portion is connected with the convex portion, the first sub-portion is arranged in a tilt manner, and the second sub-portion is in the same plane as the tab welding portion.

6. The adapter plate of claim 2, wherein, The elastic buffer portion comprises a weak portion connected with the bottom surface of the welding boss and a second connecting portion, one end of the second connecting portion is connected with the weak portion, and the other end of the second connecting portion is connected with the top surface of the tab welding portion, the thickness of the weak portion is smaller than the thickness of the second connecting portion, and the thickness direction is perpendicular to the first direction.

7. The adapter plate of claim 6, wherein, The ratio of the size of the weak portion in the first direction to the size of the elastic buffer portion in the first direction is 1:10-3:

10.

8. The adapter plate of claim 1, wherein, A plurality of elastic buffer portions are arranged along the circumference of the receiving hole, a buffer gap is arranged between two adjacent elastic buffer portions, a plurality of weight-reducing holes are arranged on the tab welding portion in a spaced manner, and the plurality of weight-reducing holes correspond to the plurality of elastic buffer portions one by one. In the radial direction of the receiving hole, the weight-reducing hole is arranged on the side of the buffer gap away from the welding boss. Or, the tab welding portion extends into the buffer gap, and in the radial direction of the receiving hole, the weight-reducing hole is arranged on the side of the elastic buffer portion away from the welding boss.

9. A cylindrical battery, characterized by The application further discloses a battery comprising the connecting piece, the pole and the shell, the shell is provided with a pole hole, the pole is arranged in the pole hole and is in sealed connection with the shell, the pole comprises an inner connecting portion, and the inner connecting portion is welded with the welding boss of the connecting piece after penetrating through the pole hole.

10. The cylindrical battery according to claim 9, characterized by The elastic buffer part includes a first connecting part connected with the bottom surface of the welding boss and a protruding part having one end connected with the first connecting part and the other end connected with the top surface of the tab welding part, the protruding part protruding toward the welding boss, and the protruding part being located on the side of the inner connecting part away from the welding boss in the radial direction of the cylindrical battery.

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