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 current collecting component, an electrode terminal and a sealing nail, the shell comprises an end wall; the electrode assembly is arranged in the shell and is provided with a first tab; the current collecting component is arranged between the end wall and the electrode assembly and is electrically connected with the first tab; the electrode terminal is mounted on the end wall in a penetrating manner; the side, away from the electrode assembly, of the electrode terminal comprises a first concave part, and the first concave part comprises a bottom wall welded to the current collecting component. The sealing nail seals the first concave part and is welded and fixed with the electrode terminal; one side, facing the electrode assembly, of the sealing nail comprises a first convex part which extends into the first concave part and faces the bottom wall; a gap exists between the bottom wall and the first convex part, the height size of the gap is H1, the height size of the electrode terminal is H2, and H1 / H2 is larger than or equal to 0.05 and smaller than or equal to 0.30. According to the utility model, the degree of electrolyte corrosion between the electrode terminal and the sealing nail can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a secondary battery and an electronic device. Background Art

[0002] With the development of new energy technology, secondary batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, etc.

[0003] During the assembly of secondary batteries, in order to achieve the positioning and installation between the electrode terminal and the sealing nail, there will inevitably be a certain installation gap between the electrode terminal and the inside of the sealing nail. This installation gap is generally close to the welding position between the current collecting component and the electrode terminal. When the welding position is welded through, the electrolyte inside the shell will enter the installation gap between the electrode terminal and the sealing nail from the welded position, and then cause a certain degree of corrosion to the electrode terminal or the sealing nail at this position, thereby affecting the performance of the secondary battery. Utility Model Content

[0004] The utility model provides a secondary battery and an electronic device, which can improve the degree of electrolyte corrosion between the electrode terminal and the sealing nail by controlling the gap between the electrode terminal and the sealing nail, thereby improving the use performance of the secondary battery.

[0005] In the first aspect, the utility model provides a secondary battery, which comprises a shell, an electrode assembly, a current collecting member, an electrode terminal and a sealing nail; the shell comprises an end wall; the electrode assembly is arranged in the shell, and the side of the electrode assembly facing the end wall has a first pole ear; the current collecting member is arranged between the end wall and the electrode assembly, and the current collecting member is electrically connected to the first pole ear; the electrode terminal is installed through the end wall and insulated from the end wall; the side of the electrode terminal away from the electrode assembly comprises a first recessed portion recessed toward the electrode assembly side, the first recess comprises a bottom wall, the bottom wall is welded to the current collecting member, and a weld mark is formed; the sealing nail seals the first recess and is welded and fixed to the electrode terminal; the side of the sealing nail facing the electrode assembly comprises a first convex portion extending into the first recess and facing the bottom wall; wherein, along the penetration direction of the electrode terminal, there is a gap between the bottom wall and the first convex portion, the height dimension of the gap is H1, the height dimension of the electrode terminal is H2, and 0.3≤H1 / H2≤0.3.

[0006] In an example of the secondary battery of the present invention, the height dimension H1 of the gap is 0.3-1.3 mm.

[0007] In an example of a secondary battery of the utility model, the side of the first recessed portion close to the bottom wall includes a housing cavity for accommodating a weld mark; the side of the first recessed portion away from the bottom wall includes a sinker; along the penetration direction of the electrode terminal, the projection of the sinker covers the projection of the housing cavity; the side of the sealing nail away from the electrode assembly includes a main body, the main body is at least partially installed on the sinker, and the first protrusion is connected to the side of the main body close to the electrode assembly, and at least partially extends to the interior of the housing cavity.

[0008] In an example of the secondary battery of the present invention, a gap between an inner wall of the accommodating cavity and an outer wall of the first protrusion is less than or equal to 0.25 mm.

[0009] In an example of the secondary battery of the utility model, the sink includes a first step hole and a second step hole connected to each other, and the second step hole is located on the side of the first step hole close to the accommodating cavity; the main body includes a first boss matching with the first step hole and a second boss matching with the second step hole.

[0010] In an example of the secondary battery of the present utility model, the matching clearance between the inner side wall of the second step hole and the outer side wall of the second boss is 0-0.25 mm.

[0011] In an example of the secondary battery of the present invention, a frustum-shaped contact surface is formed between the second boss and the second step hole, and the end of the frustum-shaped contact surface with a smaller diameter faces the electrode assembly side.

[0012] In an example of a secondary battery of the present invention, the side of the electrode terminal facing the electrode assembly includes a second recessed portion recessed toward the first recessed portion, and along the penetration direction of the electrode terminal, the orthographic projection of the top wall of the second recess at least partially coincides with the orthographic projection of the bottom wall; the recess depth of the second recess is H3, and 0.2≤H3 / H2≤0.5; the side of the current collecting member facing the second recess includes a second convex portion, and the second convex portion at least partially extends into the second recess and is welded to the top wall of the second recess.

[0013] In an example of the secondary battery of the present invention, the bottom wall includes a glue coating layer, and the glue coating layer covers the welding mark.

[0014] In a second aspect, the utility model further provides an electronic device, which includes the secondary battery provided by any one embodiment of the first aspect.

[0015] The secondary battery provided by the utility model can limit the height dimension H1 of the gap between the bottom wall and the first protrusion and the height dimension H2 of the electrode terminal by limiting the proportional relationship between the height dimension H1 of the gap and the height dimension H2 of the electrode terminal, so as to limit the height dimension H1 of the gap under the condition that the height dimension H2 remains unchanged, and further limit the volume of the gap under the condition that the cross section of the gap remains unchanged, so as to control the maximum volume of the electrolyte that can be contained in the gap, thereby controlling the degree of corrosion that can be generated by the electrolyte at the gap. Since the ratio between the dimension H1 and the dimension H2 is positively correlated with the volume of the gap, the smaller the ratio between the dimension H1 and the dimension H2, the smaller the volume of the corresponding gap, and the more conducive to reducing the degree of corrosion generated by the electrolyte at the corresponding position of the gap; however, if the ratio between the dimension H1 and the dimension H2 is too small, when the bottom wall is deformed, it is easy to generate an extrusion force on the first protrusion, and then generate a pulling force on the welding position between the sealing pin and the electrode terminal, which is easy to cause the sealing of the sealing pin to fail and cause leakage. Therefore, in the utility model, by limiting the ratio between the dimension H1 and the dimension H2 to 0.05≤H1 / H2≤0.3, not only can the gap be ensured to have a smaller volume to accommodate a smaller amount of electrolyte and reduce the degree of corrosion caused by the electrolyte to the electrode terminal and the sealing nail at this position; but the gap can also accommodate the deformation of the bottom wall during normal use of the secondary battery, reduce the squeezing force of the bottom wall on the sealing nail, and thus reduce the probability of sealing failure of the sealing nail, thereby improving the performance and service life of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a three-dimensional overall schematic diagram of an embodiment of a secondary battery of the utility model;

[0018] Figure 2 This is a cross-sectional view of the overall structure of an embodiment of a secondary battery of the utility model;

[0019] Figure 3 for Figure 2 A partial enlarged view of the middle area A;

[0020] Figure 4 It is a partial schematic diagram of the installation position of the electrode terminal and the sealing pin in one embodiment of the secondary battery of the utility model;

[0021] Figure 5 for Figure 4 A partial enlarged view of the middle area B;

[0022] Figure 6 A cross-sectional view of an electrode terminal in an embodiment of a secondary battery of the utility model;

[0023] Figure 7 A cross-sectional view of a sealing nail in an embodiment of a secondary battery of the utility model;

[0024] Figure 8 This is a partial schematic diagram of the installation positions of the electrode terminals and the sealing pins in another embodiment of the secondary battery of the utility model;

[0025] Fig. 9 This is a structural schematic diagram of a secondary battery in an embodiment of the utility model in which a bottom wall is coated with a glue layer;

[0026] Fig.10 This is a structural schematic diagram of a secondary battery in another embodiment of the utility model in which a bottom wall is coated with a glue layer;

[0027] Fig.11 This is a schematic diagram of the structure of the secondary battery of the utility model installed on a vehicle.

[0028] Component number description

[0029] 100, secondary battery; 110, housing; 111, end wall; 1111, terminal hole; 112, side wall; 120, electrode assembly; 121, first pole ear; 130, electrode terminal; 131, first recess; 1311, bottom wall; 13111, glue coating; 1312, annular wall surface; 1313, sink; 13131, first step hole; 13132, second step hole; 1314, cone-shaped contact surface; 1315, second cone surface; 132, second recess; 133, conductive part ; 134, first fixing portion; 135, second fixing portion; 136, weld mark; 137, accommodating cavity; 138, thinning area; 140, sealing pin; 141, first convex portion; 142, main body; 1421, first boss; 1422, second boss; 14221, first conical surface; 150, current collecting component; 151, second convex portion; 152, current collecting body; 160, first insulating member; 170, second insulating member; 180, sealing member; 200, electronic device; 210, working portion. DETAILED DESCRIPTION

[0030] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and the features in the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific implementation schemes, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0031] When numerical ranges are given in the embodiments, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are in accordance with the prior art mastery of those skilled in the art and the description of the present invention, and any prior art methods, equipment and materials similar or equivalent to the methods, equipment and materials in the embodiments of the present invention can also be used to implement the present invention.

[0032] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present utility model. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present utility model without substantially changing the technical content.

[0033] In the prior art, after long-term use, secondary batteries are prone to unstable conductivity on the electrode terminal side and leakage at the sealing nail installation position, which will lead to reduced performance and service life of the secondary battery. The applicant has found through a long-term study of the causes of this problem that one of the causes of this problem is that electrolyte often infiltrates between the installation gaps of the electrode terminals and the sealing nails, so that during the high-temperature operation of the secondary battery, the electrolyte reacts to produce hydrofluoric acid, causing a certain degree of corrosion to the electrode terminals and the sealing nails at this position.

[0034] In view of this, the applicant thought that the volume of electrolyte that can be accommodated in the installation gap can be reduced by reducing the size of the installation gap between the electrode terminal and the sealing pin, thereby reducing the degree of corrosion of the electrode terminal and the sealing pin by the electrolyte, and improving the performance and service life of the secondary battery. The applicant further found that the installation gap between the sealing pin and the electrode terminal generally includes a radial gap distributed along the radial direction of the sealing pin and an axial gap distributed along the axial direction of the sealing pin. Since the sealing performance between the sealing pin and the electrode terminal needs to be ensured in the actual production process, the radial gap between the sealing pin and the electrode terminal is generally much smaller than the axial gap. Therefore, by reducing the axial gap between the electrode terminal and the sealing pin, the degree of corrosion caused by the electrolyte in the installation gap between the electrode terminal and the sealing pin can be significantly improved. To this end, the applicant proposed a secondary battery and an electronic device to solve the above technical problems.

[0035] See also Figures 1 to 11 The utility model provides a secondary battery 100 and an electronic device 200. The secondary battery 100 can control the size of the gap volume between the electrode terminal 130 and the sealing nail 140 by limiting the proportional relationship between the height dimension of the gap between the bottom wall 1311 and the first protrusion 141 and the height dimension of the electrode terminal 130, thereby controlling the maximum volume of the electrolyte that can enter the gap, thereby controlling the degree of corrosion of the electrode terminal 130 and the sealing nail 140 by the electrolyte, and better ensuring the performance and service life of the secondary battery 100.

[0036] In the present application, the secondary battery 100 may include a lithium ion battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery or a magnesium ion battery, etc., which is not limited in the present embodiment. The secondary battery 100 may be cylindrical, flat, rectangular or other shapes, etc., which is not limited in the present embodiment.

[0037] See also Figure 1 and Figure 2 , further describing the structure of the secondary battery 100 , the secondary battery 100 includes a case 110 , an electrode assembly 120 , a current collecting member 150 , an electrode terminal 130 , and a sealing nail 140 .

[0038] An installation cavity is formed in the shell 110 for installing the electrode assembly 120, the electrolyte (not shown) and other components. The installation cavity can be open at one end or at both ends. Specifically, the size of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as a diameter of 46 mm, a height of 80 mm, 95 mm, 120 mm and other specifications. The shell 110 can be in a variety of shapes, such as cylindrical, prismatic, etc. The material of the shell 110 can also be a variety of 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 rust-proof material, such as metal nickel, etc., can also be plated on the surface of the shell 110.

[0039] See also Figure 1 and Figure 2 In an embodiment of the secondary battery 100 of the utility model, the shell 110 is a cylindrical structure, the shell 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111, the shell 110 includes a closed section and an open end, the end wall 111 is the closed end, and the opening opposite to the end wall 111 is the open end. The end wall 111 and the side wall 112 can be integrally formed and connected, or they can be formed separately and then welded.

[0040] See also Figure 2 and Figure 3 , the end wall 111 includes a terminal hole 1111, and the electrode terminal 130 is installed through the terminal hole 1111. The shape of the terminal hole 1111 can be a circular hole, a square hole or other polygonal structures, as long as the fixed connection requirements of the electrode terminal 130 and the end wall 111 are met. The terminal hole 1111 can be set in the central area of ​​the end wall 111, or in the outer peripheral area of ​​the end wall 111, as long as it corresponds to the installation position of the electrode terminal 130. In this embodiment, the terminal hole 1111 is a circular hole structure, and the terminal hole 1111 is coaxially arranged with the end wall 111.

[0041] For details, please continue to see Figure 3In one embodiment of the utility model, the electrode terminal 130 includes a conductive portion 133, a first fixing portion 134 and a second fixing portion 135. The conductive portion 133 is a cylindrical structure, and the conductive portion 133 passes through the terminal hole 1111. The first fixing portion 134 is arranged in the circumference of the outer end of the conductive portion 133 and is clamped on the outer side of the end wall 111; the second fixing portion 135 is arranged in the circumference of the inner end of the conductive portion 133 and is clamped on the inner side of the end wall 111. The electrode terminal 130 is insulated and isolated from the end wall 111 by the first insulating member 160 and the second insulating member 170, respectively, and the terminal hole 1111 is sealed by the first fixing portion 134 pressing the sealing member 180. The first insulating member 160 is disposed between the first fixing portion 134 and the outer wall of the end wall 111 to insulate the electrode terminal 130 from the outer wall of the end wall 111 ; the second insulating member 170 is installed between the second fixing portion 135 and the inner wall of the end wall 111 to insulate the electrode terminal 130 from the inner wall of the end wall 111 .

[0042] like Figure 2 As shown, the electrode assembly 120 is contained in the housing 110. The electrode assembly 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector; the positive electrode collector includes a positive electrode coating area and a positive electrode ear connected to the positive electrode coating area, the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode ear is not coated with a positive electrode active material layer. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector; the negative electrode collector includes a negative electrode coating area and a negative electrode ear connected to the negative electrode coating area, the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode ear is not coated with a negative electrode active material layer. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes the positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes the negative electrode active material, which can be carbon or silicon. The main matrix material of the diaphragm can be PP or PE. In order to protect and insulate the electrode assembly 120, an insulating film can also be coated on the outside of the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET, PVC or other high molecular polymer materials.

[0043] Please continue reading Figure 2 and Figure 3In an example of the secondary battery 100 of the utility model, the electrode assembly 120 is sealed and installed in the housing 110. The electrode assembly 120 is respectively provided with a first pole tab 121 and a second pole tab at both ends of the height direction of the secondary battery 100, and the polarities of the first pole tab 121 and the second pole tab are opposite, wherein the first pole tab 121 faces the end wall 111 side, and the first pole tab 121 is a positive pole tab. It should be noted that in other embodiments, the first pole tab 121 may also be a negative pole tab, and the second pole tab may be a positive pole tab.

[0044] See also Figure 3 and Figure 6 , along the penetration direction of the electrode terminal 130 on the end wall 111, the side of the electrode terminal 130 away from the electrode assembly 120 includes a first recess 131, and the first recess 131 is recessed toward the electrode assembly 120. The shape of the first recess 131 is not limited, for example, it can be a circular hole structure, a square hole structure or other special-shaped hole structures. In this embodiment, the first recess 131 is a circular hole structure. The first recess 131 includes a bottom wall 1311 on the side close to the electrode assembly 120. The current collecting member 150 is arranged between the end wall 111 and the electrode assembly 120, and the side of the current collecting member 150 away from the end wall 111 is electrically connected to the first pole ear 121, and the electrical connection method can be welding, conductive adhesive bonding connection, etc.; the side of the current collecting member 150 facing the end wall 111 contacts the bottom wall 1311, and is welded to form a weld mark 136.

[0045] See also Figure 3 and Figure 4 , the sealing nail 140 seals the first recess 131 and is welded to the electrode terminal 130. The sealing nail 140 includes a main body 142 and a first convex portion 141, and the first convex portion 141 is located on the side of the main body 142 facing the electrode assembly 120. The side of the main body 142 facing away from the electrode assembly 120 is sealed and welded to the wall of the opening side of the first recess 131, and the welding method can be seam welding, penetration welding, etc. The first convex portion 141 extends into the cavity of the first recess 131 and is arranged facing the bottom wall 1311.

[0046] The cross-sectional shape of the main body 142 and the first convex portion 141 can be circular, rectangular or other polygonal structures, as long as they can form a satisfactory installation relationship with the first concave portion 131. However, preferably, in this embodiment, the cross-sectional shapes of the main body 142 and the first convex portion 141 are both circular structures that match the cross-sectional shape of the first concave portion 131, and the main body 142 and the first convex portion 141 can be coaxially arranged or not. Preferably, in this embodiment, the main body 142 and the first convex portion 141 are coaxially arranged, which facilitates the molding process of the sealing nail 140, and also facilitates the circumferential positioning and installation of the sealing nail 140 on the electrode terminal 130, thereby improving the installation efficiency of the sealing nail 140 on the electrode terminal 130.

[0047] Along the penetration direction of the electrode terminal 130, there is a gap between the bottom wall 1311 and the first protrusion 141, and the height dimension of the gap is H1. Figure 3 As shown in . It should be noted that the height dimension of the gap refers to the height dimension between the bottom wall 1311 and the surface of the first protrusion 141 facing the bottom wall 1311. In the present embodiment, the surface of the first protrusion 141 facing the bottom wall 1311 and the bottom wall 1311 may be arranged in parallel or approximately in parallel. The height dimension of the electrode terminal 130 is H2, and 0.05≤H1 / H2≤0.3. It should be noted that the height dimension H2 of the electrode terminal 130 refers to the overall height dimension of the electrode terminal 130 along the penetration direction of the electrode terminal 130, such as Figure 3 as shown in .

[0048] In this embodiment, by limiting the ratio between the height dimension H1 and the height dimension H2, the height dimension H1 of the gap can be limited under the condition that the height dimension H2 remains unchanged, and then the volume of the gap can be limited under the condition that the cross section of the gap remains unchanged, so as to control the maximum volume of electrolyte that can be contained in the gap, thereby controlling the degree of corrosion of the electrolyte in the gap. The smaller the ratio between the dimension H1 and the dimension H2, the smaller the volume of the corresponding gap, the less the amount of electrolyte that can be contained in the gap, and the more conducive to reducing the degree of corrosion of the electrolyte at the corresponding position of the gap on the sealing nail 140 and the electrode terminal 130; however, if the ratio between the dimension H1 and the dimension H2 is too small, when the bottom wall 1311 is deformed, it is easy to generate a squeezing force on the first protrusion 141, and then it will generate a pulling force on the welding position between the main body 142 and the electrode terminal 130, which is easy to cause the sealing of the sealing nail 140 to fail and cause leakage. In this embodiment, by limiting the ratio between the dimension H1 and the dimension H2 to 0.05≤H1 / H2≤0.3, not only can the gap have a smaller volume to accommodate a smaller amount of electrolyte, thereby reducing the degree of corrosion caused by the electrolyte to the electrode terminal 130 and the sealing nail 140 at this position; but the gap can also accommodate the deformation of the bottom wall 1311 during normal use of the secondary battery 100, reducing the squeezing force of the bottom wall 1311 on the sealing nail 140, thereby reducing the probability of sealing failure of the sealing nail 140, and thus helping to improve the performance and service life of the secondary battery 100.

[0049] In an example of the secondary battery 100 of the present invention, the height dimension H1 of the gap is any value within the range of 0.3 to 1.3 mm, for example, it can be 0.3 mm, 0.5 mm, 1.0 mm or 1.3 mm, etc. The smaller the height dimension H1 of the gap is, the easier it is to interfere with the weld mark 136 on the bottom wall 1311, causing damage to the weld mark 136, thereby affecting the conductivity between the electrode terminal 130 and the electrode assembly 120. However, the less amount of electrolyte that can be accommodated in the gap, the weaker the corrosion degree of the electrolyte to the electrode terminal 130 and the sealing nail 140, and the more conducive to improving the performance and service life of the secondary battery 100. On the contrary, the larger the height dimension H1 of the gap is, the less likely it is to interfere with the weld mark 136 on the bottom wall 1311, and the more conducive it is to protect the weld mark 136, thereby ensuring that the electrode terminal 130 and the electrode assembly 120 can obtain stable electrical conductivity. However, the more electrolyte that can be accommodated in the gap, the stronger the degree of corrosion of the electrode terminal 130 and the sealing nail 140 by the electrolyte, which is less conducive to improving the performance and service life of the secondary battery 100. In this embodiment, by limiting the height dimension H1 of the gap to within the range of 0.3 to 1.3 mm, the probability of interference between the weld mark 136 on the bottom wall 1311 and the sealing nail 140 can be reduced, ensuring that the electrode terminal 130 and the electrode assembly 120 have stable electrical conductivity, and ensuring that the gap does not accommodate a large amount of electrolyte, thereby limiting the degree of corrosion of the electrode terminal 130 and the sealing nail 140 by the electrolyte, and ensuring that the secondary battery 100 has satisfactory performance and service life.

[0050] See also Figure 3 , Figure 4 and Figure 6In an example of the secondary battery 100 of the utility model, along the through direction of the electrode terminal 130, the side of the first recess 131 close to the bottom wall 1311 includes an annular wall surface 1312, one end of the annular wall surface 1312 extends toward the opening side of the first recess 131, and the other end of the annular wall surface 1312 is connected to the outer periphery of the bottom wall 1311 to form an accommodating cavity 137 for accommodating the weld mark 136. The side of the first recess 131 away from the bottom wall 1311 includes a sink 1313, and the sink 1313 can be a one-stage sink structure or a two-stage sink structure connected to each other. Along the through direction of the electrode terminal 130, the projection of the sink 1313 covers the projection of the accommodating cavity 137. The main body 142 is at least partially installed in the sink 1313, the first convex portion 141 is connected to the side of the main body 142 close to the electrode assembly 120, and the first convex portion 141 at least partially extends to the inside of the accommodating cavity 137. The side of the annular wall surface 1312 facing away from the bottom wall 1311 can be directly connected to the side of the sink 1313 close to the bottom wall 1311, or can be indirectly connected through other walls, etc., and there is no specific limitation on this. Inside the accommodating cavity 137, a matching gap can be formed between the outer wall of the first protrusion 141 and the inner wall of the annular wall surface 1312, or they can be in contact with each other, as long as the first protrusion 141 is at least partially extended into the accommodating cavity 137, and there is no specific limitation on this.

[0051] In the present embodiment, by extending at least a portion of the first protrusion 141 into the interior of the accommodating cavity 137, the first protrusion 141 is closer to the bottom wall 1311, which is beneficial to reducing the height dimension H1 of the gap between the bottom wall 1311 and the first protrusion 141, thereby reducing the volume of the gap while keeping the cross-sectional area of ​​the accommodating cavity 137 unchanged, thereby reducing the maximum volume of electrolyte that can be accommodated in the gap, reducing the degree of corrosion of the electrode terminal 130 and the sealing nail 140 caused by the electrolyte in the gap, and correspondingly improving the performance and service life of the secondary battery 100.

[0052] See also Figure 4 and Figure 5 In an example of the secondary battery 100 of the present invention, the gap between the inner wall of the accommodating cavity 137 and the outer wall of the first protrusion 141 is less than or equal to 0.25 mm, that is, the gap between the inner wall of the annular wall surface 1312 and the outer wall of the first protrusion 141 is less than or equal to 0.25 mm. Figure 5 The gap is provided between the inner wall of the annular wall surface 1312 and the outer wall of the first protrusion 141 to prevent over-positioning between the sealing nail 140 and the electrode terminal 130 during installation, thereby affecting the installation efficiency and installation accuracy of the sealing nail 140. Figure 5It can be seen that the larger the radial dimension A of the gap is, the more conducive it is to the installation of the sealing nail 140 on the first recess 131. However, since the gap is connected to the gap between the bottom wall 1311 and the first protrusion 141, there is a probability that the electrolyte enters from the gap between the bottom wall 1311 and the first protrusion 141 into the gap between the inner wall of the annular wall surface 1312 and the outer wall of the first protrusion 141, thereby increasing the degree of corrosion of the electrolyte to the electrode terminal 130 and the sealing nail 140. In this embodiment, by setting the gap between the inner side wall of the annular wall surface 1312 and the outer side wall of the first protrusion 141 to be less than or equal to 0.25 mm, it is possible to ensure that the gap between the inner side wall of the annular wall surface 1312 and the outer side wall of the first protrusion 141 is small, and reduce the probability of electrolyte entering the gap between the bottom wall 1311 and the first protrusion 141 and causing corrosion to the annular wall surface 1312 and the side wall of the first protrusion 141 at this position, further improving the performance and service life of the secondary battery 100. At the same time, it is also possible to facilitate the installation of the sealing nail 140 on the first recess 131, and ensure the installation efficiency and installation accuracy between the sealing nail 140 and the electrode terminal 130.

[0053] See also Figures 4 to 6In an example of the secondary battery 100 of the present invention, along the through direction of the electrode terminal 130, the sink 1313 includes a first step hole 13131 and a second step hole 13132, and the second step hole 13132 is located on the side of the first step hole 13131 close to the accommodating cavity 137, that is, the second step hole 13132 is located between the first step hole 13131 and the annular wall surface 1312. One end of the second step hole 13132 is connected to one end of the first step hole 13131, and the other end of the second step hole 13132 is connected to one end of the annular wall surface 1312 away from the bottom wall 1311. The specific shapes of the first step hole 13131 and the second step hole 13132 are not limited. For example, the first step hole 13131 and the second step hole 13132 can be coaxially arranged approximately cylindrical structures, or the first step hole 13131 can be an approximately rectangular structure, and the second step hole 13132 can be an approximately cylindrical structure, etc., as long as the cross-sectional area of ​​the first step hole 13131 is greater than the cross-sectional area of ​​the second step hole 13132, and along the through-direction of the electrode terminal 130, the projection of the first step hole 13131 can completely cover the projection of the second step hole 13132. Along the height direction of the sealing pin 140, the main body 142 includes a first boss 1421 and a second boss 1422 connected to each other. The first boss 1421 cooperates with the first step hole 13131, and the second boss 1422 cooperates with the second step hole 13132. The structural shapes of the first boss 1421 and the second boss 1422 can be a cylindrical structure, a frustum structure or a rectangular structure, etc., as long as the structural shape of the first boss 1421 can match the structural shape of the first step hole 13131, and the structural shape of the second boss 1422 can match the structural shape of the second step hole 13132.

[0054] In this embodiment, by providing the first step hole 13131 and the second step hole 13132, a plurality of step-shaped contact surfaces are formed between the outer wall of the sealing pin 140 and the wall of the first recess 131. On the one hand, it can increase the difficulty for the electrolyte to enter the step-shaped contact surface area from the gap between the bottom wall 1311 and the first protrusion 141, and reduce the degree of corrosion of the electrolyte on the step-shaped contact surface area, thereby further improving the performance and service life of the secondary battery 100. On the other hand, since the second boss 1422 cooperates with the second step hole 13132, the second step hole 13132 can at least partially support the lower edge of the second boss 1422. Therefore, when welding between the sealing pin 140 and the external bus, the welding solution after welding can be prevented from falling into the accommodating cavity 137, so that the welding solution can fill the gap formed by the second boss 1422 and the second step hole 13132 and solidify in the gap, thereby enhancing the reliability of the electrical connection between the electrode terminal 130 and the sealing pin 140, and ultimately improving the welding quality and electrical connection stability between the sealing pin 140 and the external bus.

[0055] See also Figure 4 and Figure 5 In an example of the secondary battery 100 of the present utility model, the matching clearance between the inner wall of the second step hole 13132 and the outer wall of the second boss 1422 is 0-0.25 mm. Figure 5 As shown in the middle dimension B. In this embodiment, by limiting the matching clearance between the inner side wall of the second step hole 13132 and the outer side wall of the second boss 1422 to between 0 and 0.25 mm, the speed at which the electrolyte diffuses from the gap between the bottom wall 1311 and the first convex portion 141 to the matching clearance between the inner side wall of the second step hole 13132 and the outer side wall of the second boss 1422 can be better suppressed, and the volume of the electrolyte that can be accommodated in the matching clearance between the inner side wall of the second step hole 13132 and the outer side wall of the second boss 1422 can be reduced, thereby further reducing the degree of corrosion of the electrode terminal 130 and the sealing nail 140 by the electrolyte. At the same time, it can also reduce the diffusion rate of the welding solution after welding in the fitting gap between the inner wall of the second step hole 13132 and the outer wall of the second boss 1422 when the sealing pin 140 is welded to the external bus, which is beneficial to the rapid solidification of the welding solution in the fitting gap, and can further ensure the stability of the welding quality and the stability of the electrical connection between the sealing pin 140 and the external bus.

[0056] See also Figures 4 to 7In an example of the secondary battery 100 of the utility model, a frustum-shaped contact surface 1314 is formed between the second boss 1422 and the second step hole 13132, and the end with a smaller diameter of the frustum-shaped contact surface 1314 faces the electrode assembly 120 side. The specific size of the height and cone angle of the frustum-shaped contact surface 1314 is not limited, and is subject to the installation and matching requirements between the second boss 1422 and the second step hole 13132. It should be noted that the frustum-shaped contact surface 1314 can be a contact surface structure formed by the side wall of the second boss 1422 being in full contact with the side wall of the second step hole 13132, or a local contact surface structure formed by the side wall of the second boss 1422 being in contact with a local area of ​​the side wall of the second step hole 13132 along the penetration direction of the electrode terminal 130, etc. In this embodiment, along the through direction of the electrode terminal 130, the side of the outer wall of the second boss 1422 close to the first boss 1421 includes a first frustum surface 14221, and the side of the inner wall of the second step hole 13132 close to the first step hole 13131 includes a second frustum surface 1315 arranged corresponding to the first frustum surface 14221, and the small ends of the first frustum surface 14221 and the second frustum surface 1315 are both facing the electrode assembly 120. The cone angle of the first frustum surface 14221 is the same or substantially the same as the cone angle of the second frustum surface 1315. Along the through direction of the electrode terminal 130, the height of the first frustum surface 14221 matches the height of the second frustum surface 1315. By providing the first frustum surface 14221 on the second boss 1422, a guiding role can be played when the second boss 1422 is installed with the second step hole 13132, thereby improving the installation efficiency and installation accuracy between the second boss 1422 and the second step hole 13132. At the same time, because the first frustum surface 14221 is provided corresponding to the second frustum surface 1315, the matching gap formed between the inner side wall of the second step hole 13132 and the outer side wall of the second boss 1422 can be further reduced, which is conducive to further reducing the volume of electrolyte that can be accommodated in the matching gap between the inner side wall of the second step hole 13132 and the outer side wall of the second boss 1422, thereby further reducing the degree of corrosion of the electrolyte on the electrode terminal 130 and the sealing nail 140.

[0057] See also Figure 8In an example of the secondary battery 100 of the utility model, the electrode terminal 130 includes a second recess 132 on the side facing the electrode assembly 120, and the second recess 132 is recessed toward the first recess 131. Along the penetration direction of the electrode terminal 130, the orthographic projection of the top wall of the second recess 132 at least partially overlaps with the orthographic projection of the bottom wall 1311. The shape of the second recess 132 is not limited, for example, the cross-section may be circular, square, etc., as long as the orthographic projection of the top wall of the second recess 132 at least partially overlaps with the orthographic projection of the bottom wall 1311. Preferably, in the present embodiment, the cross-sectional shape of the second recess 132 is circular, and is coaxially arranged with the first recess 131, so that the positioning processing between the first recess 131 and the second recess 132 can be facilitated. Along the penetration direction of the electrode terminal 130, the recess depth of the second recess 132 is H3, such as Figure 8 As shown in , and 0.2≤H3 / H2≤0.5.

[0058] In this way, a thinning area 138 with a certain thickness is formed between the top wall of the second concave portion 132 and the bottom wall 1311. On the premise that the thickness of the thinning area 138 is the same as the height dimension H2 of the electrode terminal 130, the distribution position of the bottom wall 1311 in the height direction of the electrode terminal 130 can be controlled by adjusting the proportional relationship between the dimension H3 and the dimension H2. In this embodiment, by limiting 0.2≤H3 / H2≤0.5, it can be ensured that the height dimension H1 of the gap between the bottom wall 1311 and the first protrusion 141 of the sealing nail 140 is of a reasonable size, and the electrolyte will not cause significant corrosion to the electrode terminal 130 and the sealing nail 140. At the same time, it can be ensured that the thickness of the sealing nail 140 accommodated in the first concave portion 131 can meet the thickness requirements for welding with the external bus bar.

[0059] The current collecting member 150 includes a current collecting body 152 and a second protrusion 151, and the current collecting body 152 is welded to the first electrode tab 121. Along the thickness direction of the current collecting body 152, one side of the second protrusion 151 is connected to the current collecting body 152, and the other side of the second protrusion 151 protrudes toward one side of the second recess 132, and at least partially extends into the second recess 132, and contacts and welds with the top wall of the second recess 132. In this way, the installation space occupied by the current collecting member 150 in the height direction of the secondary battery 100 can be reduced, which is conducive to improving the volume energy density of the secondary battery 100.

[0060] The specific structure of the second convex portion 151 is not limited, for example, it can be a concave cavity structure integrally stamped and formed with the current collecting body 152, or a convex column structure welded with the current collecting body 152, etc. Preferably, refer to Figure 8In this embodiment, the second convex portion 151 is a convex column structure coaxially arranged with the current collecting body 152, and the second convex portion 151 is fixedly connected with the current collecting body 152 by welding. In this way, a local thickened area can be formed on the current collecting member 150 to form a good welding process window with the bottom wall 1311, thereby reducing the probability of welding through the bottom wall 1311, thereby reducing the probability of the electrolyte inside the housing 110 entering the gap between the bottom wall 1311 and the first convex portion 141 from the welding through position, and can play a role in reducing the corrosion of the electrolyte on the installation position of the electrode terminal 130 and the sealing nail 140, thereby better improving the performance and service life of the secondary battery 100.

[0061] See also Fig. 9 In an example of the secondary battery 100 of the utility model, the bottom wall 1311 includes a glue layer 13111, and the glue layer 13111 covers the weld marks 136 distributed on the bottom wall 1311. The material of the glue layer 13111 can be a material with good corrosion resistance such as polyvinyl chloride, polyurethane, acrylate, etc. The glue layer 13111 can be only applied to the distribution area of ​​the weld marks 136 of the bottom wall 1311, or it can cover the surface of the entire bottom wall 1311. Preferably, in this embodiment, the glue layer 13111 is applied to the entire surface of the bottom wall 1311. By providing the glue layer 13111 on the bottom wall 1311, on the one hand, a sealing layer can be formed on the surface of the weld marks 136, reducing the probability of the electrolyte entering the interior of the electrode terminal 130 through the weld mark 136 on the bottom wall 1311, and reducing the degree of corrosion caused by the electrolyte to the electrode terminal 130 and the sealing nail 140. On the other hand, the coating layer 13111 can also make the surface of the bottom wall 1311 closer to the first protrusion 141, thereby reducing the height dimension H1 of the gap between the first protrusion 141 and the bottom wall 1311, and further reducing the amount of electrolyte that can be accommodated in the gap, which is more conducive to reducing the degree of corrosion of the sealing pin 140 and the electrode terminal 130 caused by the electrolyte at the corresponding position of the gap.

[0062] It should be noted that, in one embodiment, when the bottom wall 1311 includes the rubber coating layer 13111, the first protrusion 141 may also extend to the interior of the accommodating cavity 137 at the same time. Fig.10 As shown, this can further reduce the height dimension H1 of the gap between the first protrusion 141 and the bottom wall 1311 .

[0063] See also Fig.11In an embodiment of the electronic device 200 of the utility model, the electronic device 200 may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc., and may also be a battery pack, a battery module, etc. assembled from a plurality of the above-mentioned secondary batteries 100. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc.; the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc.

[0064] The embodiment of the utility model does not impose any special restrictions on the above-mentioned electronic device 200. In one embodiment of the electronic device 200 of the utility model, the electronic device 200 is a vehicle, and the vehicle includes a working part 210, and the working part 210 includes the secondary battery 100 in the above-mentioned embodiment, and the secondary battery 100 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle to realize the operation of the vehicle.

[0065] The utility model secondary battery, by limiting the ratio between the height dimension H1 and the height dimension H2, can limit the height dimension H1 of the gap under the condition that the height dimension H2 remains unchanged, and then can limit the volume of the gap under the condition that the cross section of the gap remains unchanged, so as to correspond to the maximum volume of electrolyte that can be contained in the control gap, so as to control the degree of corrosion of the electrolyte in the gap; and by limiting the ratio between the dimension H1 and the dimension H2 to 0.05≤H1 / H2≤0.30, not only can the gap be guaranteed to have a smaller volume to accommodate a smaller amount of electrolyte, but also reduce the degree of corrosion of the electrode terminal and the sealing nail at the position by the electrolyte; and the gap can also accommodate the deformation of the bottom wall during the normal use of the secondary battery, reduce the squeezing force of the bottom wall on the sealing nail, so as to reduce the probability of sealing failure of the sealing nail, so as to improve the performance and service life of the secondary battery. Therefore, the utility model effectively overcomes some practical problems in the prior art and has a high utilization value and use significance. The above embodiments only illustrate the principle and efficacy of the utility model, and are not used to limit the utility model. Anyone familiar with the technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A secondary battery, characterized in that: include: a housing including end walls; An electrode assembly is disposed in the housing, and a side of the electrode assembly facing the end wall has a first electrode tab; A current collecting member is disposed between the end wall and the electrode assembly, and the current collecting member is electrically connected to the first electrode tab; an electrode terminal, which is installed through the end wall and insulated from the end wall; the electrode terminal includes a first recessed portion recessed toward the electrode assembly on a side away from the electrode assembly, the first recess includes a bottom wall, and the bottom wall is welded to the current collecting member to form a weld mark; A sealing nail, sealing the first recess and being welded and fixed to the electrode terminal; the sealing nail includes a first protrusion extending into the first recess and facing the bottom wall on a side facing the electrode assembly; There is a gap between the bottom wall and the first protrusion along the penetration direction of the electrode terminal, the height dimension of the gap is H1, the height dimension of the electrode terminal is H2, and 0.05≤H1 / H2≤0.

30.

2. The secondary battery according to claim 1, characterized in that: The height dimension H1 of the gap is 0.3-1.3 mm.

3. The secondary battery according to claim 2, characterized in that: The side of the first recessed portion close to the bottom wall includes a housing cavity for accommodating the weld stamp; the side of the first recessed portion away from the bottom wall includes a sinker; along the penetration direction of the electrode terminal, the projection of the sinker covers the projection of the housing cavity; the side of the sealing nail away from the electrode assembly includes a main body, the main body is at least partially installed on the sinker, and the first protrusion is connected to the side of the main body close to the electrode assembly, and at least partially extends to the interior of the housing cavity.

4. The secondary battery according to claim 3, characterized in that: A gap between the inner wall of the accommodating cavity and the outer wall of the first protrusion is less than or equal to 0.25 mm.

5. The secondary battery according to claim 3, characterized in that: The sink includes a first step hole and a second step hole connected to each other, and the second step hole is located on a side of the first step hole close to the accommodating cavity; the main body includes a first boss matched with the first step hole and a second boss matched with the second step hole.

6. The secondary battery according to claim 5, characterized in that: The matching clearance between the inner side wall of the second step hole and the outer side wall of the second boss is 0-0.25 mm.

7. The secondary battery according to claim 5, characterized in that: A frustum-shaped contact surface is formed between the second boss and the second step hole, and an end of the frustum-shaped contact surface with a smaller diameter faces the electrode assembly side.

8. The secondary battery according to any one of claims 1 to 7, characterized in that: The side of the electrode terminal facing the electrode assembly includes a second recessed portion recessed toward the first recessed portion, and along the penetration direction of the electrode terminal, the orthographic projection of the top wall of the second recess at least partially coincides with the orthographic projection of the bottom wall; the recess depth of the second recess is H3, and 0.2≤H3 / H2≤0.5; the side of the current collecting member facing the second recess includes a second convex portion, and the second convex portion at least partially extends into the second recess and is welded to the top wall of the second recess.

9. The secondary battery according to claim 8, characterized in that: The bottom wall comprises a rubber coating layer, and the rubber coating layer covers the weld mark.

10. An electronic device, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 9.

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