Secondary battery and electronic device

Abstract

The utility model provides a secondary battery and an electronic device. The secondary battery comprises a shell, an electrode assembly, a pole and a current collecting component, the shell comprises an end wall and a side wall surrounding the end wall, and the end wall comprises a pole hole; the electrode assembly is accommodated in the shell, and one end, facing the end wall, of the electrode assembly is provided with a tab; the pole covers the pole hole, is fixed on the end wall and is provided with a thinning area along the height direction of the secondary battery; the current collecting component is at least partially arranged between the electrode assembly and the end wall, the current collecting component comprises a current collecting body and a welding nail which are arranged in a split mode, the current collecting body is connected with the tab in a welded mode, and the welding nail is connected with the current collecting body and the thinning area in a welded mode; the current collecting body further comprises a plurality of through grooves which are arranged around the welding nails at intervals and extend in the circumferential direction of the current collecting component, so that the technical problem that normal use of the electrode assembly is affected due to the fact that the current collecting component is easy to weld through in the welding process of the pole and the current collecting component can be solved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a secondary battery and electronic device. Background Technology

[0002] With the development of lithium battery technology, the energy density of battery cells is getting higher and higher. Cylindrical batteries, due to their higher assembly ratio, can achieve higher energy density and have therefore become a mainstream battery type.

[0003] In cylindrical batteries, the terminals and current collectors are connected by welding, and laser welding is widely used due to its advantages such as good welding quality and high welding efficiency. Laser welding is generally a through-weld, and the thickness of the weld between the terminal and the current collector directly affects the welding quality. Typically, the thickness of the terminal is greater than that of the current collector. Therefore, when laser through-welding is used between the terminal and the current collector, the welding is more difficult, and burn-through is prone to occur. This allows weld slag to fall into the electrode assembly from the burn-through point, affecting the normal operation of the electrode assembly and reducing the lifespan of the secondary battery. Utility Model Content

[0004] This invention provides a secondary battery and electronic device to improve the technical problem of welding the electrode post and current collector, which easily breaks through the current collector and affects the normal use of the electrode assembly.

[0005] To achieve the above and other related objectives, this utility model provides a secondary battery and an electronic device. The secondary battery includes a housing, an electrode assembly, terminals, and a current collector. The housing includes an end wall and a side wall surrounding the end wall, and the end wall includes a terminal hole. The electrode assembly is housed within the housing, and the end of the electrode assembly facing the end wall has a tab. The terminal covers the terminal hole and is fixed to the end wall, and has a thinning region along the height direction of the secondary battery. The current collector is at least partially disposed between the electrode assembly and the end wall. The current collector includes a separate current collector body and welding pins. The current collector body is welded to the tab, and the welding pins are welded to the current collector body and the thinning region, respectively. The current collector body also includes a plurality of through grooves spaced around the welding pins and extending circumferentially along the current collector.

[0006] In the above technical solution, a thinning zone is set on the electrode post, and welding nails are welded on the current collector body. The thinning zone and the welding nails are then welded together. The thinning zone reduces the thickness of the welded joint between the electrode post and the current collector, while the welding nails increase the thickness of the welded joint between the current collector and the electrode post. This allows for welding from the electrode post to the welding nails, which is done from thin-walled to thick-walled. Less power is needed to weld through the thinning zone, making it easier to control the welding power. This prevents the current collector from being welded through, reduces the probability of welding slag falling into the electrode assembly, and improves the service life of the secondary battery.

[0007] Furthermore, the current collector and welding pin are welded separately, which has the advantages of low processing difficulty and low cost. At the same time, multiple through slots extending circumferentially around the welding pin are arranged at intervals. The through slots can isolate the heat generated by the welding pin and the current collector body during welding, thereby reducing the deformation of the current collector body, facilitating the welding process of the current collector body and the electrode, improving the welding quality of the current collector body and the electrode, and improving the overall performance of the secondary battery.

[0008] In one example of the secondary battery of this utility model, a first connection area is formed between every two adjacent through slots. Along the circumference of the current collecting member, the shortest arc length of the first connection area is a, where 0.5mm≤a≤3mm.

[0009] In the above technical solution, a first connection area is formed between the two through slots. The first connection area can be used as a weak point for overcurrent in the path of current conduction along the radial direction of the current collector to the terminal post. It can be used as a fuse. Under extreme conditions, the first connection area will melt due to overheating, thereby cutting off the current, preventing further damage to the secondary battery and improving the safety of the secondary battery.

[0010] In one example of the secondary battery of this utility model, the width of the through groove is b, 0.5mm≤b≤2mm.

[0011] In the above technical solution, heat insulation effect can be achieved with b ≥ 0.5 mm. The larger the b value, the better the heat insulation effect. At the same time, the larger through groove can also be used as a liquid injection hole. However, if the b value is too large, it will limit the length of the weld mark formed by welding the current collector body and the electrode tab along the radial direction of the current collector component. Therefore, b ≤ 2 mm is limited to ensure the length of the weld mark formed by welding the current collector body and the electrode tab along the radial direction of the current collector component, thereby achieving the effects of reducing the battery internal resistance and improving welding strength and stability.

[0012] In one example of the secondary battery of this utility model, the diameter of the current collector body is d, and the current collector body has an annular region with an inner diameter of 0.15d and an outer diameter of 0.5d, and all through slots are located within the annular region.

[0013] In the above technical solution, the through groove is set within the range of 0.15d to 0.5d. On the one hand, this helps to ensure the length of the weld mark formed by the welding of the current collector body and the electrode tab along the radial direction of the current collector component, thereby reducing the internal resistance of the battery and improving the welding strength and stability. On the other hand, it prevents the current collector body from forming a cantilever structure due to an excessively long through groove, which would reduce the flatness and structural strength of the current collector body.

[0014] In one example of the secondary battery of this utility model, each first connection area is provided with at least one buffer portion extending circumferentially along the current collector.

[0015] In the above technical solution, the electrode assembly will shake under vibration conditions, which will pull on the weld between the welding nail and the electrode post. The buffer part can reduce the pulling force on the weld between the welding nail and the electrode post by deformation, thus improving the problem of welding failure between the current collector and the electrode post.

[0016] In one example of the secondary battery of this utility model, the buffer portion includes a protrusion protruding toward the end wall, and the protrusion has a recess formed on the side facing the electrode assembly.

[0017] In the above technical solution, the structure of the buffer part formed by setting the protrusion is simple and low in cost. The deformation of the protrusion can weaken the tensile force of the electrode assembly on the weld joint between the welding nail and the pole, thus improving the problem of welding failure between the current collector and the pole.

[0018] In one example of the secondary battery of this utility model, each first connection area is provided with a first through hole.

[0019] In the above technical solution, the cross-sectional area of ​​the first connection area can be further reduced to form a new weak point for overcurrent, which can be used as a fuse to increase the sensitivity of the first connection area to melting due to overheating, prevent further damage to the secondary battery, and improve the safety of the secondary battery.

[0020] In one example of the secondary battery of this utility model, the current collector body includes a plurality of electrode connection parts fixedly connected to the electrode tabs, a second connection area is formed between each two adjacent electrode connection parts, and a second through hole is provided on each second connection area.

[0021] In the above technical solution, the second through hole can be used as an injection hole to improve the injection efficiency, and this setting can also reduce weight.

[0022] In one example of the secondary battery of this utility model, each through slot corresponds to a tab connection part along the radial direction of the current collector body, and the second through hole extends to the first through hole.

[0023] In the above technical solution, each through groove corresponds to a tab connection part, that is, a through groove is provided between each tab connection part and the electrode post. The through groove can play a heat insulation role, so as to isolate the heat generated during the welding between the thinning area and the electrode post from the transfer to the tab connection part, thereby reducing the deformation of the current collector body, especially reducing the deformation of the tab connection part, improving the reliability of the tab connection part and the tab welding, and thus improving the overall performance of the secondary battery.

[0024] This utility model also provides an electronic device, which includes a battery pack, the battery pack including any of the above-mentioned secondary batteries.

[0025] This utility model of a secondary battery features a thinning zone on the electrode post and welding nails welded to the current collector body. The thinning zone and welding nails are then welded together. The thinning zone reduces the thickness of the welded joint between the electrode post and the current collector, while the welding nails increase the thickness of the welded joint between the current collector and the electrode post. This allows for penetration welding from the electrode post to the welding nail, moving from a thin wall to a thick wall. It requires less power to weld through the thinning zone, making it easier to control the welding power. This prevents the current collector from being welded through, reduces the probability of welding slag falling into the electrode assembly, and improves the service life of the secondary battery.

[0026] Furthermore, the current collector and welding pin are welded separately, which has the advantages of low processing difficulty and low cost. At the same time, multiple through slots extending circumferentially around the welding pin are arranged at intervals. The through slots can isolate the heat generated by the welding pin and the current collector body during welding, thereby reducing the deformation of the current collector body, facilitating the welding process of the current collector body and the electrode, improving the welding quality of the current collector body and the electrode, and improving the overall performance of the secondary battery. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 only some embodiments of this utility model. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a secondary battery according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the electrode assembly in one embodiment of the secondary battery of this utility model;

[0030] Figure 3 for Figure 1 A magnified view of a section at point A in the middle;

[0031] Figure 4 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0032] Figure 5 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0033] Figure 6 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0034] Figure 7 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0035] Figure 8 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0036] Figure 9 This is a schematic diagram of the current collector component in one embodiment of the secondary battery of this utility model;

[0037] Figure 10 This is a schematic diagram of the battery pack in one embodiment of the electronic device of this utility model;

[0038] Figure 11 This is a schematic diagram of an embodiment of the electronic device of this utility model.

[0039] Component designation explanation:

[0040] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Housing; 102. Housing cover; 100. Secondary battery; 110. Casing; 111. End wall; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. First electrode; 1211. Positive current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Second electrode; 1231. Negative current collector; 1232. Second coated area 1233, Second uncoated area; 124, First tab; 125, Second tab; 130, Current collector; 131, Current collector body; 1311, Through groove; 1312, First connection area; 1313, Buffer section; 13131, Protrusion; 1314, First through hole; 1315, Tab connection section; 1316, Second connection area; 1317, Second through hole; 132, Welding stud; 140, Cover plate; 150, Post; 151, Thinning area. Detailed Implementation

[0041] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0042] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, equipment, and materials similar to or equivalent to those in the embodiments of this invention.

[0043] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of implementation of this utility model.

[0044] A secondary battery includes an electrode assembly, which is the component in a secondary battery where electrochemical reactions occur, and may contain one or more electrode assemblies.

[0045] The secondary battery also includes a casing, a cover plate, and terminals. The casing includes an end wall and a side wall surrounding the end wall. One end of the side wall has an opening. The electrode assembly can be assembled into the casing through the opening of the casing. The cover plate is used to close the opening of the casing to achieve a seal. The terminals pass through the end wall and are electrically connected to the electrode assembly to conduct the electrical energy generated by the electrode assembly.

[0046] To improve the connection effect and yield rate between the electrode post and the electrode assembly, a current collector is provided on both the electrode post and the electrode assembly. The current collector is welded to the electrode assembly on one side and to the electrode post on the other. Laser welding is widely used due to its advantages such as good welding quality and high welding efficiency; laser welding is generally a through-welding technique.

[0047] However, the inventors discovered that the thickness of the weld between the electrode and the current collector directly affects the welding quality of the through-weld. Generally, the electrode thickness is greater than the current collector thickness. Therefore, when laser through-welding is used between the electrode and the current collector, the welding is more difficult, and burn-through is more likely to occur during the welding process. This allows weld slag to easily fall from the burn-through location into the electrode assembly, affecting the normal use of the electrode assembly and reducing the lifespan of the secondary battery.

[0048] In view of this, the present invention provides a technical solution that sets the insulating component as a separate design including a first insulator and a second insulator, sets a thinning area on the electrode post, welds a welding nail on the current collector body, and then welds the thinning area to the welding nail. This can realize that when the welding is carried out from the electrode post to the welding nail, it is a welding from the thin wall to the thick wall. This can improve the welding process between the electrode post and the current collector component, which is prone to welding through the current collector component and affecting the normal use of the electrode assembly.

[0049] Please see Figures 1 to 11 This utility model provides a secondary battery 100, a battery pack 10 and an electronic device 1. The secondary battery 100 includes a housing 110, an electrode assembly 120, a terminal post 150, a current collector 130 and a cover plate 140.

[0050] Please see Figure 1 The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the side wall 112 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical, surrounding the outer edge of the end wall 111, with a circular opening 113 formed at the end of the side wall 112 facing away from the end wall 111. A receiving cavity is formed within the housing 110 formed by the end wall 111 and the side wall 112 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 110 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, or 46mm. The shell 110 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 110 from rusting during long-term use, a layer of anti-rust material such as metallic nickel can be plated on the surface of the shell 110.

[0051] Please see Figure 1 and Figure 2 Electrode assembly 120 is disposed within housing 110 and is a component in secondary battery 100 where electrochemical reactions occur. Housing 110 may contain one or more electrode assemblies 120. Electrode assembly 120 includes a wound structure formed by stacking and winding a first electrode 121, a second electrode 123, and a separator 122. The first electrode 121 and the second electrode 123 have opposite polarities. In some embodiments, the first electrode 121 is a positive electrode and the second electrode 123 is a negative electrode; in other embodiments, the first electrode 121 is a negative electrode and the second electrode 123 is a positive electrode.

[0052] Please see Figures 1 to 2In this embodiment, the first electrode 121 is a positive electrode. The first electrode 121 includes a positive current collector 1211 and a positive active material. The positive active material is coated on the surface of the positive current collector 1211. The positive current collector 1211 includes a first coated area 1212 coated with active material and a first uncoated area 1213 uncoated with active material. The first uncoated area 1213 is located at the end of the first electrode 121. The first uncoated area 1213 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 and bends towards the winding axis to form a first tab 124. The first tab 124 is the corresponding positive tab.

[0053] Please see Figures 1 to 2 The second electrode 123 is a negative electrode. Specifically, the second electrode 123 includes a negative current collector 1231 and a negative active material. The negative active material is coated on the surface of the negative current collector 1231. The negative current collector 1231 includes a second coated area 1232 coated with active material and a second uncoated area 1233 uncoated with active material. The second uncoated area 1233 is located at the end of the second electrode 123. The other end of the second uncoated area 1233 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 and is bent toward the winding axis to form a second tab 125. The second tab 125 is the corresponding negative tab.

[0054] Please see Figures 1 to 2 A separator 122 is disposed between the first electrode 121 and the second electrode 123 to isolate the positive electrode active material layer and the negative electrode active material layer. Taking a lithium-ion secondary battery 100 as an example, the material of the positive electrode current collector 1231 can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The material of the negative electrode current collector 1211 can be copper, and the negative electrode active material can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 120, an insulating film can also be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0055] Please see Figure 1 and Figure 2Furthermore, if the first tab 124 faces the end wall 111 or the opening 113, then the second tab 125 faces the other end of the housing 110. In this embodiment, the first tab 124 faces the end wall 111 and is electrically connected to the post 150, making the post 150 positively charged. The second tab 125 faces the opening 113, and the housing 110 is electrically connected to the second tab 125, thus becoming negatively charged. However, in another embodiment, the second tab 125 can be connected to the post 150, and the first tab 124 can be connected to the housing 110.

[0056] Please see Figure 1 The cover plate 140 is sealed and installed on the opening 113. The outer edge shape of the cover plate 140 corresponds to the shape of the opening 113 and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 140 includes, but is not limited to, mechanical sealing or welding sealing. In this embodiment, the cover plate 140 is sealed and plugged on the opening 113 by means of mechanical sealing.

[0057] Please see Figure 1 and Figure 3 The end wall 111 includes a pole post hole 1111, and the pole post 150 covers the pole post hole 1111 and is fixed to the end wall 111. The pole post 150 can penetrate the end wall 111 through the pole post hole 1111, or it can not penetrate the end wall 111, as long as it can be fixedly connected to the end wall 111 and can cover the pole post hole 1111, there is no limitation in this regard. In this embodiment, the pole post 150 is installed through the pole post hole 1111. As long as insulation and sealing between the pole post 150 and the end wall 111 can be achieved, the installation method of the pole post 150 on the end wall 111 is not limited. The structural form of the pole post 150 can be any suitable form that can pass through the end wall 111 and be electrically connected to the first tab 124 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or an irregular contour that can achieve stable conductivity. The shape of the pole post hole 1111 corresponds to the shape of the pole post 150. In this embodiment, the cross-section of the pole post 150 is circular. Furthermore, the specific location of the pole hole 1111 on the end wall 111 is not limited. Preferably, in this embodiment, the pole hole 1111 is located at the center of the end wall 111. This arrangement facilitates the circumferential positioning and installation of the pole 150 on the end wall 111, which is beneficial to improving assembly efficiency. In other embodiments, two or more pole holes 1111 may be provided on the end wall 111, as long as the installation and usage requirements are met.

[0058] Please see Figure 3To facilitate through-welding on the terminal post 150 and weld the terminal post 150 and the first tab 124 together, the terminal post 150 is further provided with a thinning region 151 along the height direction of the secondary battery 100. The thinning region 151 has a surface that can be exposed to the outside of the housing 110. The shape of the thinning region 151 is not limited. For example, it can be square, annular, circular or irregular, as long as it has enough welding surface to meet the requirements of external welding.

[0059] Please see Figure 3 To improve the connection effect and yield between the electrode post 150 and the electrode assembly 120, the electrode post 150 and the electrode assembly 120 are electrically connected through a current collector 130. Specifically, the current collector 130 is at least partially disposed between the electrode assembly 120 and the end wall 111. Considering that the thickness of the electrode post 150 is generally greater than the thickness of the current collector 130, the welding is more difficult when laser penetration welding is used between the electrode post 150 and the current collector 130. During the welding process, the current collector 130 is prone to be welded through, which causes the welding slag to fall into the electrode assembly 120 from the weld penetration position. Therefore, the inventors provided a thickened part for welding connection on the current collector 130. In order to reduce the processing difficulty and production cost of the current collector 130, the current collector 130 includes a separate current collector body 131 and a welding nail 132. The current collector body 131 is welded to the electrode tab, and the welding nail 132 is welded to the current collector body 131 and the thinning area 151 respectively. Specifically, the welding nail 132 is welded on the current collector body 131 and at the position corresponding to the thinning area 151. A thinning region 151 is provided on the electrode post 150, and a welding nail 132 is welded on the current collector body 131. The thinning region 151 and the welding nail 132 are then welded together. The thinning region 151 reduces the thickness of the weld between the electrode post 150 and the current collector 130, while the welding nail 132 increases the thickness of the weld between the current collector 130 and the electrode post 150, making it less prone to weld-through. At the same time, it can also achieve welding from the electrode post 150 to the welding nail 132 from the thin wall to the thick wall, requiring less power to weld through the thinning region 151, making it easier to control the welding power, further preventing weld-through of the current collector 130, reducing the probability of welding slag falling into the electrode assembly 120, and improving the service life of the secondary battery 100.

[0060] Please see Figure 4 and Figure 5Considering that the heat generated during the welding connection between the welding stud 132 and the current collecting body 131 will cause deformation of the current collecting body 131, reduce the flatness of the current collecting body 131, and thus affect the welding quality, the current collecting body 131 also includes a plurality of through slots 1311 that are spaced around the welding stud 132 and extend circumferentially along the current collecting member 130. The shape and number of through slots 1311 are not limited, for example, they can be arc-shaped, straight, curved, or other irregular shapes, and there can be two, three, four or more. In this embodiment, four through slots 1311 are provided, and there is a gap between each pair of adjacent through slots 1311 to prevent the current collecting body 131 from breaking at the through slots 1311. The through slot 1311 can also isolate the heat generated during welding of the welding nail 132 and the current collector 131, thereby reducing the deformation of the current collector 131, facilitating the welding process of the current collector 131 and the electrode, improving the welding quality of the current collector 131 and the electrode, and improving the overall performance of the secondary battery 100.

[0061] Please see Figure 4 In one example of the secondary battery 100 of this utility model, a first connection area 1312 is formed between every two adjacent through slots 1311. The first connection area 1312 can serve as a weak point for overcurrent in the path of current conduction along the radial direction of the current collector 130 to the terminal post 150, and can be used as a fuse. Along the circumference of the current collector 130, the shortest arc length of the first connection area 1312 is a, 0.5mm≤a≤3mm. By limiting the shortest arc length of the first connection area 1312 to the above range, it is possible that under extreme operating conditions, the first connection area 1312 will melt due to overheating, thereby cutting off the current, preventing further damage to the secondary battery 100, and improving the safety of the secondary battery 100.

[0062] Please see Figures 4 to 5 In one example of the secondary battery 100 of this utility model, the width of the through groove 1311 is b, where 0.5mm ≤ b ≤ 2mm. For example, it can be 0.5mm, 1mm, 1.5mm, or 2mm, etc. A heat insulation effect can be achieved if b ≥ 0.5mm; the larger the b value, the better the heat insulation effect. Simultaneously, a larger through groove 1311 can also be used as an injection hole. Please refer to [link / reference]. Figure 5 However, an excessively high value of b would limit the length of the weld mark formed by welding the current collector body 131 and the electrode tab along the radial direction of the current collector component 130. Therefore, b is limited to ≤ 2 mm to ensure the length of the weld mark formed by welding the current collector body 131 and the electrode tab along the radial direction of the current collector component 130, thereby achieving the effects of reducing the battery internal resistance and improving welding strength and stability.

[0063] Please see Figure 5In one example of the secondary battery 100 of this utility model, the diameter of the current collector body 131 is d, and the current collector body 131 has an annular region with an inner diameter of 0.15d and an outer diameter of 0.5d. All through slots 1311 are located within the annular region. Setting the through slots 1311 within the range of 0.15d to 0.5d has two advantages. First, it helps to ensure the length of the weld mark formed by welding the current collector body 131 and the electrode tab along the radial direction of the current collector component 130, thereby reducing the internal resistance of the battery and improving the welding strength and stability. Second, it prevents the current collector body 131 from forming a cantilever structure due to excessively long through slots 1311, which would reduce the flatness and structural strength of the current collector body 131.

[0064] Please see Figure 6 Considering that the electrode assembly 120 may shake under vibration conditions, thereby pulling on the weld between the welding pin 132 and the electrode post 150, in one example of the secondary battery 100 of this utility model, each first connection area 1312 is provided with at least one buffer portion 1313 extending circumferentially along the current collector 130. The buffer portion 1313 can take various forms, such as a curved protrusion, a wavy protrusion, or a zigzag bend structure, as long as it can weaken the pulling force of the electrode assembly 120 on the weld between the welding pin 132 and the electrode post 150 through the current collector 130 through its own deformation. This arrangement improves the problem of welding failure between the current collector 130 and the electrode post 150.

[0065] Please see Figure 6 In one example of the secondary battery 100 of this utility model, the buffer portion 1313 includes a protrusion 13131 protruding towards the end wall 111, and the protrusion 13131 has a recess on the side facing the electrode assembly 120. The structure of the buffer portion 1313 formed by setting the protrusion 13131 is simple and low in cost, and the deformation of the protrusion 13131 can reduce the tensile force of the electrode assembly 120 on the weld joint between the welding pin 132 and the terminal post 150, thereby improving the problem of welding failure between the current collector 130 and the terminal post 150.

[0066] In one example of the secondary battery 100 of this utility model, each first connection area 1312 is provided with a first through hole 1314. The number and shape of the first through holes 1314 are not limited, and there can be one or more. In one embodiment, please refer to... Figure 7 The first through hole 1314 is circular. In another embodiment, please refer to [reference needed]. Figure 8The first through hole 1314 is rhomboid. In some other embodiments, it can also be elliptical, polygonal, or other irregular shapes. Regardless of the shape, the cross-sectional area of ​​the first connection area 1312 can be further reduced, forming a new weak point for overcurrent, which can be used as a fuse to increase the sensitivity of the first connection area 1312 to melting due to overheating, prevent further damage to the secondary battery 100, and improve the safety of the secondary battery 100.

[0067] Please see Figure 9 In one example of the secondary battery 100 of this utility model, the current collector body 131 includes a plurality of electrode connection portions 1315 fixedly connected to the electrode tabs. Specifically, the portion of the current collector body 131 welded to the electrode tabs is the electrode connection portion 1315. The shape and position of the electrode connection portion 1315 are not limited. Preferably, in this embodiment, four electrode connection portions 1315 welded to the electrode tabs are formed on the current collector body 131. The four electrode connection portions 1315 are evenly arrayed along the circumference of the current collector body 131. This arrangement can improve the welding balance stability between the current collector component 130 and the electrode tabs and has a more uniform current guiding effect, thereby improving the stability of current guiding between the housing 110 and the electrode assembly 120. A second connection area 1316 is formed between every two adjacent electrode connection portions 1315, and a second through hole 1317 is provided on each second connection area 1316. The second through hole 1317 can be used as a liquid injection hole to improve the liquid injection efficiency. This arrangement can also reduce weight. The shape of the second through hole 1317 is not limited and can be fan-shaped, square, circular, triangular, or other irregular shapes, etc., and can be adapted to the space of the second connection area 1316. In this embodiment, the second through hole 1317 is triangular. This setting can ensure the welding area of ​​the electrode connection part 1315, and also allow a larger liquid injection hole to be formed on the current collector body 131, so as to improve the liquid injection efficiency and reduce weight.

[0068] Please see Figure 9 In one example of the secondary battery 100 of this utility model, along the radial direction of the current collector body 131, each through groove 1311 corresponds to a tab connection portion 1315, and the second through hole 1317 extends to the first through hole 1314. That is, a through groove 1311 is provided between each tab connection portion 1315 and the electrode post 150. The through groove 1311 can play a heat insulation role, so as to prevent the heat generated during the welding between the thinned area 151 and the electrode post 150 from being transferred to the tab connection portion 1315, thereby reducing the deformation of the current collector body 131, especially reducing the deformation of the tab connection portion 1315, improving the reliability of the tab connection portion 1315 and the tab welding, and thus improving the overall performance of the secondary battery 100. The extension of the second through hole 1317 to the first through hole 1314 is beneficial to increasing the area of ​​the second through hole 1317, and also beneficial to improving the sensitivity of the first connection area 1312 as a safety device.

[0069] Please see Figure 11 This utility model also provides an electronic device 1, which includes a battery pack 10. Please refer to [link / reference]. Figure 10 The battery pack 10 includes any of the aforementioned secondary batteries 100. In one embodiment of the battery pack 10 of this utility model, the battery pack 10 includes a housing 101, a cover 102, and multiple secondary batteries 100. The multiple secondary batteries 100 are placed in the housing 101 and are connected in series or in parallel, or a combination of series and parallel connections. The cover 102 seals the housing 101 to protect the multiple secondary batteries 100. It should be noted that, in addition to the secondary batteries 100 of this utility model, the battery pack 10 may also include a battery pack thermal management system, circuit boards, etc. The battery pack 10 can be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0070] Further, please refer to Figure 11 The working part 11 is electrically connected to the battery pack 10 to obtain electrical power. As an example, the electronic device 1 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 11 is the vehicle body, and the battery pack 10 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 1 can also be a mobile phone, portable device, laptop, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part 11 can be a unit component capable of obtaining electrical power from the battery pack 10 and performing corresponding tasks, 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 1.

[0071] This utility model of a secondary battery features a thinning zone on the electrode post and welding nails welded to the current collector body. The thinning zone and welding nails are then welded together. The thinning zone reduces the thickness of the electrode post at the weld point with the current collector, while the welding nails increase the thickness of the current collector at the weld point. This allows for penetration welding from the electrode post to the welding nail, moving from a thin-walled to a thick-walled structure. Lower power is required to weld through the thinning zone, facilitating power control and preventing weld penetration of the current collector. This reduces the probability of weld slag falling into the electrode assembly and improves the battery's lifespan. Therefore, this utility model effectively overcomes some practical problems in the prior art, thus possessing high utilization value and significance. The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit its scope. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model shall still be covered by the claims of this utility model.

Claims

1. A secondary battery, characterized in that, include: The housing includes an end wall and a side wall surrounding the end wall, the end wall including a pole post hole; An electrode assembly is housed within the housing, and the end of the electrode assembly facing the end wall has a tab; The electrode post covers the electrode post hole and is fixed to the end wall, and has a thinning area along the height direction of the secondary battery; A current collector is at least partially disposed between the electrode assembly and the end wall. The current collector includes a separate current collector body and a welding pin. The current collector body is welded to the electrode tab, and the welding pin is welded to the current collector body and the thinning region, respectively. The current collection body further includes multiple through slots that are spaced around the welding nails and extend circumferentially along the current collection component.

2. The secondary battery according to claim 1, characterized in that, A first connection area is formed between each pair of adjacent through slots. Along the circumference of the flow collecting member, the shortest arc length of the first connection area is a, where 0.5mm≤a≤3mm.

3. The secondary battery according to claim 1, characterized in that, The width of the through groove is b, where 0.5mm ≤ b ≤ 2mm.

4. The secondary battery according to claim 1, characterized in that, The diameter of the flow collecting body is d, and the flow collecting body has an annular region with an inner diameter of 0.15d and an outer diameter of 0.5d, and all the through slots are located within the annular region.

5. The secondary battery according to claim 2, characterized in that, Each of the first connection areas is provided with at least one buffer portion extending circumferentially along the flow collection member.

6. The secondary battery according to claim 5, characterized in that, The buffer portion includes a protrusion that protrudes toward the end wall, and the protrusion has a recess on the side facing the electrode assembly.

7. The secondary battery according to any one of claims 2, 5, or 6, characterized in that, Each of the first connection areas is provided with a first through hole.

8. The secondary battery according to claim 7, characterized in that, The current collector body includes a plurality of electrode connection parts fixedly connected to the electrode tabs, a second connection area is formed between each two adjacent electrode connection parts, and a second through hole is provided on each second connection area.

9. The secondary battery according to claim 8, characterized in that, Along the radial direction of the current collecting body, each of the through slots corresponds to one of the electrode connecting portions, and the second through hole extends to the first through hole.

10. An electronic device, characterized in that, It includes a battery pack, the battery pack comprising the secondary battery according to any one of claims 1 to 9.

Images