Secondary battery and electronic device

Abstract

The present application relates to a secondary battery and an electronic device. The secondary battery comprises a case, a terminal post and a sealing assembly. The terminal post comprises a first portion, a second portion and a third portion. The first portion is arranged in the case; one end of the second portion is connected to the first portion, and the other end of the second portion extends out of the case through a first through hole in the case; and the third portion is connected to the second portion outside the case. The terminal post further comprises a first hole, an opening of which is located on the surface of the third portion facing away from the second portion; and a first relief structure is provided on the outer surface of the second portion. The sealing assembly comprises a first sealing ring, a second sealing ring and a third sealing ring, wherein the first sealing ring of the sealing assembly is arranged between a first wall surface of the case and the first portion; the second sealing ring is arranged around the second portion; and the third sealing ring is arranged between a second wall surface and the third portion. The secondary battery and the electronic device provided in the present application can improve the technical problem of a poor sealing performance caused by the low strength and susceptibility to deformation of the terminal post of the secondary battery.

Description

Secondary batteries and electronic devices

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202410674438.1, filed on May 20, 2024, entitled “Secondary Battery and Electronic Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a secondary battery and electronic device. Background Technology

[0004] Rechargeable batteries are crucial for the normal operation of mobile devices, serving as their power source. As mobile devices such as smartphones and laptops become increasingly prevalent, end-users are demanding higher capacity and longer battery life from rechargeable batteries. Hard-cased rechargeable batteries, compared to pouch batteries, can be designed to achieve significantly higher capacities. Summary of the Invention

[0005] Traditional hard-shell secondary batteries require terminals that are welded to the tabs of the internal electrode assembly to indicate polarity. The inventors of this application discovered that welding the terminals to the internal tabs requires a large space within the battery casing. However, limited casing space makes welding inconvenient, leading to poor connection strength between the terminals and tabs, and the large space also reduces the battery's energy density. The inventors of this application solve this problem by using hollow terminals, with openings on the outer surface. Through-welding can be used directly at these openings outside the casing to achieve electrical connection between the terminals and tabs, eliminating the need for additional space. This improves the battery's energy density and simplifies the process, enhancing the connection strength. However, the hollow terminals weaken the overall strength, making the terminals and sealing rings prone to deformation and misalignment during clamping and riveting, resulting in poor sealing.

[0006] The purpose of this application is to provide a secondary battery and electronic device, which aims to improve the technical problem of low strength and easy deformation of the secondary battery terminals, resulting in poor sealing performance.

[0007] According to a first aspect of this application, a secondary battery is provided, including a housing, terminals, and a sealing assembly. The housing includes a first wall portion having a first through hole, and the first wall portion includes a first wall surface and a second wall surface disposed opposite to each other, the first wall surface facing the inner cavity of the housing. The terminals include a first portion, a second portion, and a third portion. The first portion is disposed inside the housing, one end of the second portion is connected to the first portion, and the other end of the second portion extends out of the housing from the first through hole, and the third portion is connected to the second portion outside the housing. 。 The pole also includes a first hole, the opening of which is located on the surface of the third part facing away from the second part, and the outer surface of the second part is provided with a first uneven structure. The sealing assembly includes a first sealing ring, a second sealing ring, and a third sealing ring. The first sealing ring is disposed between the first wall surface and the first part, the second sealing ring is disposed around the second part, and the third sealing ring is disposed between the second wall surface and the third part.

[0008] In the above technical solution, a first hole is provided on the outer surface of the third part. The welding equipment can realize the electrical connection between the electrode post and the electrode assembly at the first hole, without reserving space inside the housing. This not only facilitates operation but also improves the energy density of the secondary battery. Furthermore, because the electrical connection between the electrode post and the electrode assembly is simpler and more convenient, it is easier to improve the connection strength between the electrode post and the electrode assembly.

[0009] Meanwhile, the first concave-convex structure increases the strength of the second part of the terminal post, reducing its deformation and thus decreasing the gap between the terminal post and the sealing ring, thereby improving the sealing performance of the secondary battery. Furthermore, the first concave-convex structure increases the connection area between the second sealing ring and the second part, further enhancing the sealing performance between the second sealing ring and the terminal post.

[0010] Furthermore, the aforementioned first concave-convex structure enhances the strength of the electrode post and increases the connection area between the second sealing ring and the electrode post, resulting in stronger sealing performance. Therefore, the length of the second part can be reduced, decreasing the space occupied by the electrode post and further improving the energy density of the secondary battery.

[0011] In some preferred embodiments, along the first direction, the projection of the first concave-convex structure overlaps with the first hole, and the first concave-convex structure is distributed on the outside of the first hole to reduce the influence of the first hole on the pole strength.

[0012] In some preferred embodiments, the projection of the first wall portion overlaps with the first hole along the first direction to facilitate electrical connection between the pole and the electrode assembly.

[0013] In some preferred embodiments, the first hole has a bottom wall, which is disposed opposite to the opening along the direction from the first wall surface to the second wall surface. The bottom wall of the first hole is located on the side of the first wall portion away from the third portion, leaving enough space to facilitate the electrical connection between the pole and the electrode assembly and improve the connection strength.

[0014] In some preferred embodiments, the second sealing ring is provided with a second concave-convex structure, which fits into the first concave-convex structure, can fully fill the gap between the second part and the housing, and can increase the connection area between the second sealing ring and the second part, thereby improving the sealing performance between the pole and the housing.

[0015] In some preferred embodiments, the first convex-concave structure is an external thread provided on the outer surface of the second portion, and the second convex-concave structure is an internal thread provided on the second sealing ring, with the second sealing ring threadedly connected to the second portion. The second sealing ring can be threadedly connected to the second portion by rotating it, making installation convenient and quick.

[0016] In some preferred embodiments, the secondary battery further includes a gasket disposed between the third portion and the third sealing ring. The gasket isolates the third portion from the third sealing ring, reducing direct pressure damage to the third sealing ring during riveting.

[0017] In some preferred embodiments, along the direction from the first wall surface to the second wall surface, the length of the first portion is L1, 0.1mm≤L1≤3mm; the length of the second portion is L2, 0.5mm≤L2≤5mm;

[0018] The length of the third part is L3, where 0.1mm ≤ L3 ≤ 3mm. The length of the second part is adaptively reduced, decreasing the space occupied by the electrode post and thus increasing the energy density of the secondary battery.

[0019] In some preferred embodiments, along the direction from the first wall to the second wall, the length of the third portion is L3, the length of the second portion is L2, and the depth of the first hole is D, where L3 + L2 / 2 ≤ D ≤ L3 + L2. This not only facilitates welding of the electrode post to the electrode assembly and improves the connection strength, but also gives the first portion of the electrode post high strength, reducing breakage at the connection between the electrode post and the electrode assembly.

[0020] In some preferred embodiments, the electrode post includes at least one of aluminum, copper, or aluminum alloy, which has good electrical conductivity, thermal conductivity, corrosion resistance, etc., and is highly machinable, making it easy to rivet and seal the electrode post.

[0021] In some preferred embodiments, the first, second, and third parts are integrally formed. There are no connection gaps between the three parts, improving sealing performance. Furthermore, the integral form provides greater strength and stronger resistance to deformation after riveting, reducing installation gaps caused by deformation and thus improving sealing performance.

[0022] In some preferred embodiments, the first convex-concave structure includes a first protrusion having a bottom near the first hole and a top away from the first hole. Along the direction from the first wall surface to the second wall surface, the width of the bottom is W1, and the width of the top is W2, where W2 ≤ W1. A larger top width can improve the strength and deformation resistance of the second part. A smaller top width facilitates the embedding of the second sealing ring between adjacent first protrusions, improving sealing performance.

[0023] In some preferred embodiments, 0.1mm ≤ W1 ≤ 1mm.

[0024] In some preferred embodiments, the distance from bottom to top is H, where 0.1mm ≤ H ≤ 1mm. This facilitates the installation of the second sealing ring while ensuring full engagement between the second sealing ring and the first convex-concave structure, increasing the connection area and thus improving sealing performance.

[0025] In some preferred embodiments, the thickness of the second part along the direction from the first hole to the first concave-convex structure is T, 0.5mm≤T≤2mm, which can reduce the deformation or skewing of the pole post, and the hollow structure makes the electrical connection between the pole post and the electrode assembly more convenient.

[0026] Secondly, this application also proposes an electronic device including a secondary battery as described in any of the embodiments of the first aspect above.

[0027] Additional aspects and advantages of the embodiments of this application will be described, shown, or illustrated in part by way of implementation of the embodiments of this application in the following description. Attached Figure Description

[0028] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the dimensions in the drawings do not constitute a limitation on scale.

[0029] Figure 1 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application;

[0030] Figure 2 is a schematic diagram of the structure of the housing in some embodiments of this application;

[0031] Figure 3 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application;

[0032] Figure 4 is a partial schematic diagram of the pole post riveting structure of some embodiments of this application;

[0033] Figure 5 is a partial exploded view of the pole post riveting structure of some embodiments of this application;

[0034] Figure 6 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application;

[0035] Figure 7 is a magnified view of part A in Figure 5.

[0036] Explanation of reference numerals in the attached drawings: 100, secondary battery; 10, casing; 11, inner cavity; 12, first wall portion; 121, first wall surface; 122, second wall surface; 13, first through hole; 20, electrode assembly; 21, tab; 30, electrode post; 31, first part; 32, second part; 321, first concave-convex structure; 3211, first protrusion; 3212, top; 3213, bottom; 33, third part; 34, first hole; 341, bottom wall; 40, sealing assembly; 41, first sealing ring; 42, second sealing ring; 421, second concave-convex structure; 43, third sealing ring; 50, gasket; X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0038] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0039] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0040] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0041] The technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0042] A first aspect of this application discloses a secondary battery 100. Referring to Figure 1, the secondary battery 100 includes a housing 10, an electrode assembly 20, a terminal post 30, and a sealing assembly 40. The electrode assembly 20 is disposed within the housing 10. One end of the terminal post 30 is electrically connected to the electrode assembly 20, and the other end extends outside the housing 10. The sealing assembly 40 is disposed between the terminal post 30 and the housing 10, serving to insulate and separate the terminal post 30 from the housing 10, and to seal the installation gap between the terminal post 30 and the housing 10.

[0043] Referring to Figures 1 and 2, the housing 10 encloses an inner cavity 11. The secondary battery 100 also includes an electrode assembly 20 and an electrolyte (not shown in the figures), both of which are housed within the inner cavity 11. The housing 10 includes a first wall portion 12, located at the top of the housing 10 and covering the inner cavity 11. The first wall portion 12 includes a first wall surface 121 and a second wall surface 122 disposed opposite to each other. The first wall surface 121 faces the inner cavity 11 of the housing 10, and the second wall surface 122 faces away from the inner cavity 11 of the housing 10. The first wall portion 12 has a first through hole 13, which penetrates the first wall surface 121 and the second wall surface 122, communicating with the inner cavity 11 of the housing 10. The aforementioned electrode post 30 can be installed at the first through hole 13.

[0044] In the embodiments of this application, the secondary battery 100 can be a hard-shell secondary battery 100, and the casing 10 can be a structure formed by stamping a single layer of metal sheet, such as a single layer of steel sheet, which can improve the strength of the casing 10 and its resistance to deformation. In some other embodiments, the casing 10 can also be made of metal materials such as stainless steel, nickel, or copper. Compared with the soft-pack secondary battery 100, the hard-shell secondary battery 100 in this application can be designed to achieve a higher capacity, which is convenient for meeting the design requirements of large capacity and long battery life of the secondary battery 100.

[0045] Referring to Figure 1, the electrode assembly 20 is disposed within the inner cavity 11 of the housing 10. The electrolyte can wet the electrode assembly 20 within the inner cavity 11 of the housing 10 to achieve an electrochemical reaction. The electrode assembly 20 can adopt a stacked structure, comprising a positive electrode (not shown in the figure), a negative electrode (not shown in the figure), and a separator (not shown in the figure). A plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked, and the separator is disposed between the positive electrode plates and the negative electrode plates to insulate and separate them.

[0046] In some other embodiments, the electrode assembly 20 may also adopt a wound structure, that is, the positive electrode sheet, the separator and the negative electrode sheet are stacked and wound together to form a wound electrode assembly 20.

[0047] The aforementioned terminal post 30 acts as a "bridge" connecting to an external circuit, responsible for conducting the current generated inside the secondary battery 100 to the external circuit and conducting external current into the secondary battery 100. The terminal post 30 can be disposed in the first through hole 13 of the housing 10, with one end of the terminal post 30 electrically connected to the electrode assembly 20 within the inner cavity 11 of the housing 10, for example, connected to the tab 21 of the electrode assembly 20, while the other end extends outside the housing 10 to connect to an external circuit, thereby enabling the charging and discharging of the secondary battery 100. The tab 21 can be sheet-like, plate-like, disc-like, or columnar, as long as it can electrically connect to the terminal post 30.

[0048] In the embodiments of this application, the housing 10 is a metal housing 10, which is conductive and can be used as the positive or negative electrode of the secondary battery 100. For example, the terminal 30 serves as the positive electrode of the secondary battery 100 and is electrically connected to the positive electrode of the electrode assembly 20, while the housing 10 serves as the negative electrode, with the negative electrode of the electrode assembly 20 directly electrically connected to the housing 10; when the terminal 30 serves as the negative electrode, the housing 10 can serve as the positive electrode. In some other embodiments, at least two terminals 30 may be used, with at least one terminal 30 serving as the positive electrode of the secondary battery 100 and at least one terminal 30 serving as the negative electrode of the secondary battery 100.

[0049] The electrode post 30 can adopt a riveted structure. Referring to Figures 2 and 3, the electrode post 30 includes a first part 31, a second part 32, and a third part 33. The first part 31 is disposed inside the housing 10 and is electrically connected to the electrode assembly 20, for example, through the tab 21 to the positive or negative electrode plate of the electrode assembly 20. One end of the second part 32 is connected to the first part 31, and the other end extends out of the housing 10 through the first through hole 13. The third part 33 is connected to the second part 32 outside the housing 10 and is used for electrical connection to an external circuit.

[0050] Optionally, during installation, the electrode post 30 is cylindrical in shape. It can be first placed in the first through hole 13, and then both ends of the electrode post 30 can be riveted and flattened to form the first part 31, the second part 32, and the third part 33. After riveting, along the first direction X, the widths of the first part 31 and the third part 33 are both greater than the width of the second part 32. The first part 31 and the third part 33 clamp the second part 32, reducing the likelihood of the electrode post 30 detaching from the housing 10.

[0051] In some embodiments, the first part 31, the second part 32, and the third part 33 are integrally formed, with no connection gap between the three parts, which improves the sealing performance. Furthermore, the integral form has greater strength and stronger resistance to deformation after riveting, which can reduce the installation gap caused by deformation and thus improve the sealing performance.

[0052] In some embodiments, the electrode post 30 comprises at least one of aluminum, copper, or an aluminum alloy. For example, the electrode post 30 is made of aluminum. Aluminum electrode posts 30 have good electrical conductivity, thermal conductivity, corrosion resistance, and ductility, and are highly machinable, facilitating the riveting and sealing of the electrode post 30. During riveting, the aluminum electrode post 30 can be slightly compressed, thereby filling the gap between the electrode post 30 and the sealing assembly 40 and improving the sealing performance.

[0053] The sealing assembly 40 is disposed between the terminal post 30 and the housing 10 to seal the installation gap between the terminal post 30 and the housing 10, thereby sealing the inner cavity 11 of the housing 10. When the terminal post 30 and the housing 10 are respectively used as the positive and negative terminals of the secondary battery 100, the sealing assembly 40 can also insulate and separate the terminal post 30 and the housing 10.

[0054] Referring to Figure 3, the sealing assembly 40 includes a first sealing ring 41, a second sealing ring 42, and a third sealing ring 43. The first sealing ring 41 is disposed between the first wall surface 121 and the first portion 31, serving to separate the first portion 31 from the housing 10. The second sealing ring 42 is disposed around the second portion 32, serving to separate the second portion 32 from the housing 10. The third sealing ring 43 is disposed between the second wall surface 122 and the third portion 33, serving to separate the third portion 33 from the housing 10.

[0055] The first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 may be made of at least one of polypropylene (PP), polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamide (PA), or phenolic resin (PF). For example, using phenolic resin provides the sealing rings with superior heat resistance and electrical insulation.

[0056] In some embodiments, referring to Figures 3 and 4, the secondary battery 100 further includes a gasket 50, which is disposed between the third portion 33 and the third sealing ring 43. During the riveting of the terminal post 30, the gasket 50 can isolate the third portion 33 from the third sealing ring 43, reducing direct pressure damage to the third sealing ring 43 by the third portion 33 during riveting. The gasket 50 can be a metal gasket, such as stainless steel, carbon steel, or copper, suitable for high-voltage conditions.

[0057] In some other embodiments, the gasket 50 may also be made of rubber, plastic, or polytetrafluoroethylene. Optionally, a gasket 50 may also be provided between the first part 31 and the first sealing ring 41 to reduce direct pressure damage to the first sealing ring 41 by the first part 31 and improve the integrity of the sealing assembly 40.

[0058] In some embodiments, the electrode post 30 may have a hollow structure. Referring to Figure 3, the electrode post 30 further includes a first hole 34, the opening of which is located on the surface of the third portion 33 opposite to the second portion 32. The first hole 34 may penetrate the third portion 33, or extend from the third portion 33 into the second portion 32, or simultaneously penetrate both the third portion 33 and the second portion 32, or penetrate both the third portion 33 and the second portion 32 and extend into the first portion 31.

[0059] The hollow structure of the electrode post 30 facilitates electrical connection between the electrode post 30 and the electrode assembly 20 from outside the housing 10. Electrical connection methods include, but are not limited to, welding, conductive adhesive bonding, or snap-fitting. For example, taking welding as an example, the welding equipment extends from outside the housing 10 into the first hole 34 of the electrode post 30. By placing the tab 21 of the electrode assembly 20 (which is electrically connected to the positive or negative electrode plate, serving as a connecting adapter) against the lower end of the electrode post 30, laser penetration welding is performed to weld and fix the electrode post 30 to the tab. This eliminates the need for pre-reserved space within the housing 10, simplifying operation and increasing the energy density of the secondary battery 100. Furthermore, the simpler and more convenient electrical connection between the electrode post 30 and the electrode assembly 20 enhances the connection strength. The welding method is not limited to laser welding; ultrasonic welding or electron beam welding can also be used.

[0060] In some embodiments, please further refer to Figures 4 and 5 (Figure 5 is a partially exploded view of the riveted structure of the pole post 30, with only a portion of each sealing ring shown). The outer surface of the second part 32 is provided with a first concave-convex structure 321. The provision of the first concave-convex structure 321 improves the strength of the second part 32 and reduces the deformation of the second part 32, such as reducing the riveting or collision deformation of the pole post 30, thereby reducing the installation gap caused by the deformation of the pole post 30 and improving the sealing performance between the second sealing ring 42 and the pole post 30. Because the second part 32 of the pole post 30 is provided with the first concave-convex structure 321, the pole post 30 has higher strength and stronger resistance to deformation. Even with a hollow structure, the pole post still has high strength.

[0061] In some embodiments, along the first direction X, the projection of the first concave-convex structure 321 overlaps with the first hole 34, and the first concave-convex structure 321 is distributed on the outside of the first hole 34, reducing the influence of the first hole 34 on the strength of the electrode post 30. It should be noted that the portion of the electrode post 30 with the first hole 34 has weaker strength, while the portion without the first hole 34 still has higher strength. In this embodiment, the first concave-convex structure 321 can be provided only on the outside of the electrode post 30 with the first hole 34, reducing the influence of the first hole 34 on the strength of the electrode post 30, while the portion without the first hole 34 (e.g., the portion of the first part 31 or the second part 32 where the first hole 34 is not reached) does not need to have the first hole 34, reducing the space occupied by the first concave-convex structure 321 and reducing the impact on the energy density of the secondary battery 100.

[0062] In this configuration, the first direction X is perpendicular to the direction from the first wall 121 to the second wall 122 (the third direction Z). For example, the first direction X, the second direction Y, and the third direction Z are all perpendicular to each other; along the second direction Y, the projection of the first concave-convex structure 321 also overlaps with the first hole 34.

[0063] The first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 can all be made of flexible material to fully fill the installation gap between the pole post 30 and the housing 10. When the second sealing ring 42 is arranged around the second part 32, the second sealing ring 42 can fill the first concave-convex structure 321 and cooperate with the first concave-convex structure 321. The arrangement of the first concave-convex structure 321 can increase the connection area between the second sealing ring 42 and the second part 32, which can further improve the sealing performance between the second sealing ring 42 and the pole post 30.

[0064] The first uneven structure 321 can be a protruding part and / or a recessed groove on the outer surface of the second part 32. The uneven setting increases the friction between the second part 32 and the second sealing ring 42 and increases the connection area between the second part 32 and the second sealing ring 42, resulting in stronger sealing performance.

[0065] In other embodiments, the portion of the second part 32 that contacts the second sealing ring 42 may be provided with a first concave-convex structure 321, thereby increasing the connection area between the second part 32 and the second sealing ring 42. A larger contact area results in stronger sealing performance. Since the third sealing ring 43 is disposed between the second wall surface 122 and the third part 33, the third sealing ring 43 may also contact the second part 32. The portion of the second part 32 that contacts the third sealing ring 43 may also be provided with a first concave-convex structure 321, further improving sealing performance while increasing the strength of the pole post 30.

[0066] Furthermore, due to the aforementioned first concave-convex structure 321, the strength of the electrode post 30 is significantly improved, and the connection area between the second sealing ring 42 and the electrode post 30 is increased, resulting in stronger sealing performance. Therefore, the length of the second part 32 can be reduced, the space occupied by the electrode post 30 can be reduced, and the energy density of the secondary battery 100 can be further improved. For example, along the direction from the first wall surface 121 to the second wall surface 122 (third direction Z), the length of the second part 32 is L2, 0.5mm≤L2≤5mm, which improves the sealing performance while increasing the energy density of the secondary battery 100. The length of the first part 31 is L1, 0.1mm≤L1≤3mm; and the length of the third part 33 is L3, 0.1mm≤L3≤3mm, reducing the deformation and skewness of the first part 31 and the third part 33, and improving the sealing performance.

[0067] Regarding the depth of the first hole 34, if the depth is too small, it will be difficult to weld the electrode post 30, which may lead to unstable electrical connection between the electrode post 30 and the electrode assembly 20. If the depth of the first hole 34 is too large, the first part 31 may be too thin, reducing its strength. As the part that is electrically connected to the electrode assembly 20, reduced strength of the first part 31 may cause damage and breakage at the connection between the electrode post 30 and the electrode assembly 20. In the embodiments of this application, referring to Figures 3 and 4, the depth D of the first hole 34 is selected as L3+L2 / 2≤D≤L3+L2. This not only facilitates the penetration welding of the electrode post 30 and the electrode assembly 20, improving the connection strength, but also gives the first part 31 of the electrode post 30 higher strength, reducing damage and breakage at the connection between the electrode post 30 and the electrode assembly 20.

[0068] In some embodiments, referring further to FIG6, the projection of the first wall portion 12 along the first direction X overlaps with the first hole 34, so as to facilitate the electrical connection between the pole post 30 and the electrode assembly 20 and to enable the pole post 30 to have higher strength.

[0069] In some other embodiments, the first hole 34 has a bottom wall 341. Along the direction from the first wall surface 121 to the second wall surface 122 (third direction Z), the bottom wall 341 is positioned opposite the opening, and is located on the side of the first wall portion 12 away from the third portion 33. Taking welding as an example, the welding equipment can directly act on the bottom wall 341 at the first hole 34 to perform penetration welding. By positioning the bottom wall 341 on the side of the first wall portion 12 away from the third portion 33, the difficulty of penetration can be reduced, and sufficient space is reserved in the first hole 34 to facilitate the electrical connection between the electrode post 30 and the electrode assembly 20, improving the connection strength. Simultaneously, this gives the electrode post 30 higher strength to reduce deformation.

[0070] The aforementioned first concave-convex structure 321 not only improves the strength of the electrode post 30 and reduces its riveting deformation, but also increases the connection area between the second sealing ring 42 and the second electrode post 30, improving sealing performance. Simultaneously, due to the increased strength and improved sealing performance of the electrode post 30, its length can be reduced, decreasing the space it occupies and thus increasing the energy density of the secondary battery 100. Furthermore, a first hole 34 can be provided in the third portion 33 of the electrode post 30, facilitating electrical connection between the electrode post 30 and the electrode assembly 20 without requiring pre-reserved operating space for electrical connection, further improving the energy density of the secondary battery 100.

[0071] In some embodiments, the second sealing ring 42 is bonded between the second portion 32 and the housing 10, which can improve the bonding strength between the housing 10 and the second portion 32 and reduce the skew deformation of the pole post 30. Similarly, the first sealing ring 41 is bonded between the first portion 31 and the first wall surface 121 of the housing 10, and the third sealing ring 43 is bonded between the third portion 33 and the second wall surface 122 of the housing 10, further improving the bonding strength between the pole post 30 and the housing 10, reducing the deformation of the pole post 30, and thus improving the sealing performance.

[0072] In some embodiments, referring to Figures 4 and 5, the second sealing ring 42 is provided with a second concave-convex structure 421, which is adapted to the first concave-convex structure 321. When the second sealing ring 42 is fitted with the second part 32, the second concave-convex structure 421 can directly fit with the first concave-convex structure 321, thereby fully filling the gap between the second part 32 and the housing 10, and increasing the connection area between the second sealing ring 42 and the second part 32, thereby improving the sealing performance between the pole post 30 and the housing 10.

[0073] It should be noted that the above-mentioned fitting can be that the shapes and dimensions of the first concave-convex structure 321 and the second concave-convex structure 421 are matched. For example, both the first concave-convex structure 321 and the second concave-convex structure 421 have protruding portions and recessed portions. The protruding portion of the first concave-convex structure 321 fills the recessed portion of the second concave-convex structure 421, and the protruding portion of the second concave-convex structure 421 fills the recessed portion of the first concave-convex structure 321, which can be regarded as fitting. The above-mentioned matching can mean that the shapes and dimensions are consistent or approximately consistent. When the protruding portion fills the recessed portion, under the condition of meeting the overall sealing requirements of the secondary battery 100, there is a small gap and / or no gap between the protruding portion and the recessed portion. When there is a small gap, the small gap is covered by the second sealing ring 42 and the second portion 32.

[0074] In some embodiments, the first concave-convex structure 321 can be an external thread provided on the outer surface of the second portion 32, and the second concave-convex structure 421 can be an internal thread provided on the second sealing ring 42. The second sealing ring 42 can be directly threadedly connected to the second portion 32. During installation, the second sealing ring 42 can be sleeved on the outer surface of the second portion 32, and then the second sealing ring 42 can be rotated to make the second sealing ring 42 threadedly connected to the second portion 32. The installation operation is convenient and quick. The pole post 30 is placed at the first through hole 13 of the first wall portion 12, and the first portion 31, the second portion 32, and the third portion 33 are formed by riveting. During riveting, the second portion 32 is tightened with the inner wall of the first hole 34, so that the second sealing ring 42 fully fills the gap between the second portion 32 and the housing 10, thereby improving the sealing performance.

[0075] The external thread protrudes on the second part 32, and the second sealing ring 42 can be press-fitted with the second part 32. When the second sealing ring 42 is rotated to make the second sealing ring 42 threadedly connected with the second part 32, the press-fit can fully fill the gap between the second sealing ring 42 and the second part 32, thereby improving the sealing performance.

[0076] In some embodiments, the first sealing ring 41 may be integrally formed with the second sealing ring 42, and during installation, the second sealing ring 42 may be directly placed into the first through hole 13 from the inner cavity 11 of the housing 10; or, the second sealing ring 42 may be integrally formed with the third sealing ring 43, and during installation, the second sealing ring 42 may be directly placed into the first through hole 13 from the outside of the housing 10. Alternatively, the first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 may be integrally formed, and by utilizing the flexibility of each sealing ring, after the housing 10 compresses the first part 31, the first part 31 may be directly placed into the inner cavity 11 of the housing 10, and the second part 32 may be located at the first through hole 13.

[0077] In some other embodiments, the first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 can be set separately. The second sealing ring 42 can be first arranged around the second part 32, the first sealing ring 41 can be arranged between the first part 31 and the first wall surface 121 during riveting, and the third sealing ring 43 can be arranged between the third part 33 and the second wall surface 122.

[0078] In some embodiments, referring to Figures 4 to 7, the first convex-concave structure 321 includes a first protrusion 3211, the provision of the first protrusion 3211 makes the second portion 32 stronger. A recess is formed between two adjacent first protrusions 3211, and the aforementioned third sealing ring 43 can be embedded in the recess, thereby increasing the connection area between the third sealing ring 43 and the second portion 32.

[0079] Regarding the shape of the first protrusion 3211, viewed along the second direction Y, the first protrusion 3211 can be triangular, rectangular, or trapezoidal, etc. For example, taking a trapezoidal shape, the first protrusion 3211 has a bottom 3213 near the first hole 34 and a top 3212 away from the first hole 34. Along the direction from the first wall surface 121 to the second wall surface 122, the width of the bottom 3213 is W1, and the width of the top 3212 is W2, where W2 ≤ W1. The width of the top 3212 can be set to be larger to improve the strength of the second part 32 and enhance its resistance to deformation. A smaller width of the top 3212 facilitates the embedding of the second sealing ring 42 between two adjacent first protrusions 3211, facilitating the filling of the gap between the pole post 30 and the second sealing ring 42, and improving sealing performance. The aforementioned first direction X, second direction Y, and third direction Z are all mutually perpendicular.

[0080] Among them, 0.1mm≤W1≤1mm can not only improve the strength of the second part 32, but also facilitate the embedding of the second sealing ring 42 and the first concave-convex structure 321, thereby improving the sealing performance.

[0081] If the height of the first protrusion 3211 is too large, the second sealing ring 42 will be difficult to install on the second part 32; if the height of the first protrusion 3211 is too small, the connection area will be small, which is not conducive to improving the sealing performance. In the embodiments of this application, referring to Figure 7, the distance from the bottom 3213 to the top 3212 along the first direction X is H, 0.1mm≤H≤1mm. This facilitates the installation of the second sealing ring 42 while ensuring sufficient engagement between the second sealing ring 42 and the first concave-convex structure 321, increasing the connection area and thus improving the sealing performance.

[0082] The second part 32 is disposed in the first through hole 13. The second part 32 serves as a connector between the inner first part 31 and the outer third part 33, and its strength also affects the deformation resistance of the electrode post 30. In the embodiments of this application, the electrode post 30 adopts a hollow structure, and the first hole 34 enables electrical connection between the electrode post 30 and the electrode assembly 20 outside the housing 10.

[0083] In the embodiments of this application, referring to Figure 5, along the direction from the first hole 34 to the first concave-convex structure 321 (first direction X), the thickness of the second portion 32 is T, 0.5mm≤T≤2mm. Combined with the first concave-convex structure 321, the hollow structure of the electrode post 30 can also have high strength, sufficient to reduce deformation or skewing of the electrode post 30, and the hollow structure of the electrode post 30 makes electrical connection between the electrode post 30 and the electrode assembly 20 more convenient. It should be noted that the thickness of the second portion 32 mentioned above does not include the first concave-convex structure 321.

[0084] A second aspect of this application also provides an electronic device including the secondary battery 100 described in any embodiment of the first aspect. The electronic device in this application is not particularly limited and can be any electronic device known in the prior art. For example, electronic devices include, but are not limited to, Bluetooth headsets, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0085] Example 1: Preparation of Lithium-ion Batteries

[0086] <Preparation of the positive electrode>:

[0087] The positive electrode active material is lithium iron phosphate, the positive electrode conductive agent is acetylene black, and the positive electrode binder is polyvinylidene fluoride (PVDF, with a weight average molecular weight of 5×10⁻⁶). 5 The materials were mixed at a mass ratio of 94:3:3, with N-methylpyrrolidone (NMP) added as a solvent. The mixture was stirred under vacuum until a homogeneous positive electrode slurry with a solid content of 75 wt% was obtained. An 8 μm thick aluminum foil was selected as the positive electrode current collector, and the foil was cut to create the inner electrode tabs. The positive electrode slurry was uniformly coated onto one surface of the aluminum foil and dried at 110°C to obtain a positive electrode sheet with a single-sided coating of positive active material (80 μm thick). The above steps were then repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coating of positive active material.

[0088] <Preparation of Negative Electrode Sheets>

[0089] Graphite powder (negative electrode active material), conductive carbon black (Super P) (conductive agent), and styrene-butadiene rubber (SBR) (binder) were mixed in a weight ratio of 97.5:1:1.5. Deionized water was then added as a solvent to prepare a negative electrode slurry with a solid content of 50 wt%, and the mixture was stirred thoroughly. A 5 μm thick copper foil was selected as the negative electrode current collector, and the inner electrode tabs were cut from the copper foil. The negative electrode slurry was uniformly coated onto one surface of the copper foil and dried at 90°C to obtain a negative electrode active material with a weight of 9.1 mg / cm³. 2 Single-sided negative electrode sheet. After completing the above steps, the single-sided coating of the negative electrode sheet is complete. Then, repeat the above steps on the other surface of the negative electrode sheet to obtain a negative electrode sheet with a double-sided coating of negative electrode active material layer.

[0090] <Preparation of the separating membrane>

[0091] A porous polyethylene (PE) film with a thickness of 8 μm was used as the separator.

[0092] <Electrolyte Preparation>

[0093] In a dry argon atmosphere, ethylene carbonate, methyl ethyl carbonate and diethyl carbonate are mixed in a mass ratio of 30:50:20 to obtain an organic solution. Then, lithium hexafluorophosphate is added to the organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0094] <Preparation of Lithium-ion Batteries>

[0095] The separator, positive electrode, separator, and negative electrode prepared above are stacked in sequence and wound to obtain an electrode assembly. The electrode assembly is then hot-pressed at a pressure of 5 MPa, a temperature of 65°C, and a holding time of 10 s.

[0096] The electrode assembly is placed in a steel housing with a first through hole. A hollow electrode post is used, and the electrode post is positioned at the first through hole in the housing. One end of the electrode post extends beyond the first through hole and is located inside the housing, while the other end extends beyond the first through hole and is located outside the housing. The portion of the electrode post located within the first through hole has a first uneven structure, while the portion outside the housing has the first hole.

[0097] A sealing ring is fitted onto the electrode post, extending from inside the housing to the outside. The ends of the electrode post are riveted and flattened using a riveting device, forming a first, second, and third part. The second part is 5mm long (refer to the length along the third direction Z in Figure 4), the first part is 0.5mm long, and the third part is 0.8mm long. The sealing ring between the first part and the housing is the first sealing ring, the sealing ring between the second part and the housing is the second sealing ring, and the sealing ring between the third part and the housing is the third sealing ring. Laser penetration welding is used to weld the electrode post to the inner tab of the positive electrode at the first hole, and the housing is directly connected to the inner tab of the negative electrode. After removing moisture at 80°C, electrolyte is injected and the electrode is sealed.

[0098] In Comparative Example 1, unlike Example 1, the pole post does not have a first hole or a first concave-convex structure.

[0099] The relevant parameters for Comparative Examples 2 to 3 and Examples 2 to 8 can be found in Table 1 below.

[0100] Drop test method: The lithium-ion battery was pretreated at 25℃ and left to stand at room temperature for 60 minutes. The voltage of the lithium-ion battery before the drop test was measured. The lithium-ion battery was placed in a fixture and dropped freely from a height of 1.5m on the ground using a drop device in the following order: head-tail-right corner of head-right corner of tail-left corner of head-left corner of tail (angle: 45±15°), repeated 6 times. After the drop test, the battery was left to stand at room temperature for 24 hours. The appearance of the top terminal of the lithium-ion battery was checked and photographed before and after the test. The test pass criteria were: no smoke or leakage at the top terminal, and the connection between the terminal and the positive inner tab of the lithium-ion battery was undamaged and unbroken when disassembled. 20 lithium-ion batteries were tested, and the number of batteries that failed the test was X, with a failure rate of X / 20. The test results are shown in Table 1 below.

[0101] Table 1

[0102] According to Table 1 above, and in conjunction with Examples 1 to 8 and Comparative Examples 1 to 3, it can be seen that when the electrode post is equipped with a first concave-convex structure and a first hole, the test failure rate is significantly reduced. This is because the first concave-convex structure increases the connection area between the second sealing ring and the second part, improving the sealing performance between the second sealing ring and the electrode post, thereby reducing the risk of leakage of the lithium-ion battery. Furthermore, the first hole facilitates electrical connection between the electrode post and the positive electrode inner tab from outside the casing, easily increasing the connection area between the electrode post and the positive electrode inner tab, thus improving the connection strength and reducing the risk of breakage at the connection point. Simultaneously, the first concave-convex structure makes the electrode post stronger, reducing deformation and tilting of the electrode post when the lithium-ion battery is impacted, thereby reducing the gap caused by deformation and tilting, and thus reducing the risk of battery leakage.

[0103] In Comparative Example 1, the absence of a first hole hinders the electrical connection between the electrode post and the inner positive electrode tab, making it difficult to increase the connection area and resulting in low connection strength. Furthermore, a large space is required for electrical connection operations within the lithium-ion battery casing. This reserved space may be used for electrode assembly movement, making the connection between the electrode post and the inner positive electrode tab prone to damage or breakage during drop tests. The reserved space also affects the energy density of the lithium-ion battery. Comparative Example 1 also lacks a first concave-convex structure, resulting in lower electrode post strength and susceptibility to deformation. Deformation of the electrode post during impact increases the installation gap between the electrode post and the casing, leading to a higher impact failure rate. Additionally, the small connection area between the electrode post and the sealing ring results in poor sealing, increasing the risk of leakage and smoke during drop tests.

[0104] In Comparative Example 2, only the first hole is provided without the first concave-convex structure. This results in lower pole strength, making it prone to deformation. Upon impact, the deformation of the pole increases the installation gap between the pole and the housing, leading to a higher failure rate. Furthermore, the connection area between the pole and the sealing ring is small, resulting in poor sealing.

[0105] In Comparative Example 3, a first concave-convex structure is provided but a first hole is not provided. It is difficult to electrically connect the electrode post and the inner tab of the positive electrode. Space needs to be reserved in the casing for the electrical connection between the electrode post and the inner tab of the positive electrode. The electrical connection operation is inconvenient, which not only affects the energy density of the lithium-ion battery, but also reduces the connection area, causing damage and breakage at the connection between the electrode post and the inner tab of the positive electrode.

[0106] In the above embodiments, due to the setting of the first concave-convex structure, the strength of the electrode post is improved, and the connection area between the second sealing ring and the electrode post is increased, resulting in stronger sealing performance. The length of the second part can be reduced to reduce the space occupied by the electrode post, thereby improving the energy density of the lithium-ion battery. Furthermore, the setting of the first hole eliminates the need to reserve additional space for the electrical connection between the electrode post and the inner tab of the positive electrode, which can further improve the energy density of the lithium-ion battery.

[0107] In combination with Examples 1 to 8, Examples 1 to 6, and Example 8, the risk of drop failure is lower than that of Example 7. This may be because in Example 7, the electrode length is too short, which may reduce the connection area and have little effect on improving sealing performance. In Example 8, the risk of drop failure is the same as that of Example 1, but in Example 1, the electrode is shorter and occupies less space, allowing the lithium-ion battery of Example 1 to have a higher energy density. Therefore, in this application, the length L2 of the second part of the electrode can be selected as 0.5mm ≤ L2 ≤ 5mm.

[0108] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A secondary battery, characterized in that, include: The housing includes a first wall portion having a first through hole, the first wall portion including a first wall surface and a second wall surface disposed opposite to each other, the first wall surface facing the inner cavity of the housing; The electrode post includes a first part, a second part, and a third part. The first part is disposed inside the housing. One end of the second part is connected to the first part, and the other end extends out of the housing from the first through hole. The third part is connected to the second part outside the housing. The electrode post also includes a first hole. The opening of the first hole is located on the surface of the third part opposite to the second part. The outer surface of the second part is provided with a first concave-convex structure. A sealing assembly includes a first sealing ring, a second sealing ring, and a third sealing ring. The first sealing ring is disposed between the first wall surface and the first portion, the second sealing ring is disposed around the second portion, and the third sealing ring is disposed between the second wall surface and the third portion.

2. The secondary battery according to claim 1, characterized in that, Along a first direction, the projection of the first concave-convex structure overlaps with the first hole; wherein, the first direction is perpendicular to the direction from the first wall surface to the second wall surface.

3. The secondary battery according to claim 1, characterized in that, Along the first direction, the projection of the first wall overlaps with the first hole.

4. The secondary battery according to claim 3, characterized in that, The first hole has a bottom wall, which is disposed opposite to the opening along the direction from the first wall to the second wall. The bottom wall of the first hole is located on the side of the first wall that is away from the third part.

5. The secondary battery according to claim 1, characterized in that, The second sealing ring is provided with a second concave-convex structure, which fits into the first concave-convex structure.

6. The secondary battery according to claim 1, characterized in that, The first concave-convex structure is an external thread provided on the outer surface of the second part, and the second concave-convex structure is an internal thread provided on the second sealing ring. The second sealing ring is threadedly connected to the second part.

7. The secondary battery according to claim 1, characterized in that, The secondary battery also includes a gasket, which is disposed between the third portion and the third sealing ring.

8. The secondary battery according to claim 1, characterized in that, Along the direction from the first wall to the second wall, the length of the second portion is L2, 0.5mm≤L2≤5mm.

9. The secondary battery according to any one of claims 1 to 8, characterized in that, Along the direction from the first wall surface to the second wall surface, The length of the first part is L1, where 0.1mm ≤ L1 ≤ 3mm; The length of the third part is L3, where 0.1mm ≤ L3 ≤ 3mm.

10. The secondary battery according to claim 1, characterized in that, Along the direction from the first wall to the second wall, the length of the third part is L3, the length of the second part is L2, the depth of the first hole is D, and L3+L2 / 2≤D≤L3+L2.

11. The secondary battery according to claim 1, characterized in that, The pole comprises at least one of aluminum, copper, or an aluminum alloy.

12. The secondary battery according to claim 1, characterized in that, The first part, the second part, and the third part are set up as a whole.

13. The secondary battery according to claim 1, characterized in that, The first concave-convex structure includes a first protrusion having a bottom near the first hole and a top away from the first hole; Along the direction from the first wall to the second wall, the width of the bottom is W1, and the width of the top is W2, where W2 ≤ W1.

14. The secondary battery according to claim 13, characterized in that, 0.1mm≤W1≤1mm.

15. The secondary battery according to claim 13, characterized in that, The distance from the bottom to the top is H, where 0.1mm ≤ H ≤ 1mm.

16. The secondary battery according to claim 1, characterized in that, Along the direction from the first hole to the first concave-convex structure, the thickness of the second part is T, 0.5mm≤T≤2mm.

17. An electronic device, characterized in that, Includes the secondary battery as described in any one of claims 1 to 16.

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