Batteries and electronics

Abstract

The present invention discloses a battery and electronic product, wherein the battery includes a positive metal shell, a negative metal shell, a sealed insulator, and a battery cell; the positive metal shell, the negative metal shell, and the sealed insulator form a sealed cavity, and the battery cell is located in the sealed cavity; the positive and / or negative metal shells have a welded portion, the welded portion formed by the sidewall of a molten pressure differential liquid hole, the aperture d1 of the pressure differential liquid hole being greater than or equal to one-tenth of the hole sidewall thickness D and less than or equal to nine-tenths of the hole sidewall thickness D; the thickness of the welded portion is less than the hole sidewall thickness D at its corresponding position, and the radial dimension of the welded portion is greater than the radial dimension of the pressure differential liquid hole; the middle portion of the welded portion is recessed from the exterior of the battery shell toward the interior of the sealed cavity, and the minimum thickness H of the welded portion is greater than or equal to one-tenth of the hole sidewall thickness D and less than or equal to nine-tenths of the sidewall thickness. The battery proposed by the present invention is conducive to significantly improving battery safety.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery and an electronic product. Background Art

[0002] Batteries are common electrochemical energy storage devices, widely used in electronics and other applications. For example, button batteries are often used in wearable electronics. With the development of wearable electronics, the demand for button batteries, such as stability, has become increasingly stringent. During actual user use, battery short circuits and excessive gas generation during charge and discharge can pose a safety hazard. Existing batteries lack a pressure relief mechanism and are sealed in a sealed state, posing a safety hazard. Summary of the Invention

[0003] The main purpose of the present invention is to provide a battery, aiming to solve the technical problem of how to improve the safety of sealed batteries.

[0004] To achieve the above-mentioned object, the battery proposed in the present invention includes a positive electrode metal shell, a negative electrode metal shell, a sealed insulator and a battery cell;

[0005] The positive electrode metal shell, the negative electrode metal shell and the sealed insulator form a sealed cavity, and the battery cell is located in the sealed cavity;

[0006] The positive electrode shell and / or the negative electrode metal shell has a welding portion, the welding portion is formed by the side wall of the molten pressure differential liquid hole, wherein the pressure differential liquid hole is used for electrolyte to enter or flow out of the closed cavity under the working condition that there is a pressure difference between the closed cavity and the outside, and the aperture d1 of the pressure differential liquid hole is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the thickness D of the hole side wall;

[0007] The thickness of the welding portion is smaller than the thickness D of the hole side wall at the corresponding position thereof, and the radial dimension of the welding portion is larger than the radial dimension of the pressure differential liquid hole;

[0008] The middle part of the welding part is recessed from the outside of the battery shell toward the inside of the closed cavity, and the minimum thickness H of the welding part is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the side wall thickness.

[0009] Optionally, the welding portion includes a melting portion and a welding portion, the melting portion is located outside the pressure difference liquid hole, and the welding portion is located inside the pressure difference liquid hole for sealing the pressure difference liquid hole.

[0010] Optionally, the welding portion is arranged in an end column shape, the end surface of the welding portion adjacent to the melting portion is arranged in a concave shape, and the end away from the melting portion is convex toward the closed cavity.

[0011] Optionally, the volume of the molten portion is greater than or equal to the volume of the welded portion, and the volume ratio of the molten portion to the welded portion is 1.2-3.

[0012] Optionally, a ratio L1:L2 between a radial dimension L1 of the fusion portion extending in the radial direction of the differential pressure liquid hole and an axial dimension L2 of the fusion portion extending in the axial direction of the differential pressure liquid hole is 0.75-2.

[0013] Optionally, a ratio L2:D between an axial dimension L2 of the molten portion extending along the axial direction of the differential pressure liquid hole and a hole depth D of the differential pressure liquid hole is 1 / 3 to 2 / 3.

[0014] Optionally, a ratio between a radial dimension L1 of the molten portion extending in a radial direction of the pressure differential liquid hole and a radius d1 / 2 of the pressure differential liquid hole is 1-5.

[0015] Optionally, the battery further includes a sealing layer, which is filled above the melting portion and the welded portion so that the top surface of the sealing layer is flush with the outer surface of the shell.

[0016] Optionally, the diameter d of the pressure differential liquid hole is 0.01 mm to 0.1 mm; and / or,

[0017] The thickness of the shell is 0.08mm-0.25mm; and / or,

[0018] The battery is any one of a button battery, a mobile phone battery, and a ring battery.

[0019] The present invention further provides an electronic product, comprising a device body and a battery, wherein the battery is electrically connected to the device body to provide electrical energy to the device body;

[0020] The battery includes a positive electrode metal shell, a negative electrode metal shell, a sealed insulator and a battery cell;

[0021] The positive electrode metal shell, the negative electrode metal shell and the sealed insulator form a sealed cavity, and the battery cell is located in the sealed cavity;

[0022] The positive electrode shell and / or the negative electrode metal shell has a welding portion, the welding portion is formed by the side wall of the molten pressure differential liquid hole, wherein the pressure differential liquid hole is used for electrolyte to enter or flow out of the closed cavity under the working condition that there is a pressure difference between the closed cavity and the outside, and the aperture d1 of the pressure differential liquid hole is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the thickness D of the hole side wall;

[0023] The thickness of the welding portion is smaller than the thickness D of the hole side wall at the corresponding position thereof, and the radial dimension of the welding portion is larger than the radial dimension of the pressure differential liquid hole;

[0024] The middle part of the welding part is recessed from the outside of the battery shell toward the inside of the closed cavity, and the minimum thickness H of the welding part is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the side wall thickness.

[0025] In the present application, a welding portion is provided on the positive electrode shell and / or the negative electrode metal shell, and the welding portion is formed by the side wall of the molten pressure differential liquid hole, wherein the pressure differential liquid hole is used for the electrolyte to enter or flow out of the closed cavity under the working condition that there is a pressure difference between the closed cavity and the outside world. At the same time, the aperture d1 of the pressure differential liquid hole is set to be greater than or equal to one tenth of the hole side wall thickness D, and less than or equal to nine tenths of the hole side wall thickness D, so that the aperture of the pressure differential liquid hole is very appropriate. The pressure required for the electrolyte to pass through the pressure differential liquid hole will not be too high because the aperture d1 is less than one tenth of the hole side wall thickness D, thereby avoiding the risk of the side wall of the shell being deformed due to bearing excessive pressure, which is beneficial to improving the stability of the battery; and the aperture d1 will not be greater than nine tenths of the hole side wall thickness D, thereby reducing the production difficulty, improving the reliability of the molten seal, and improving the stability of the battery.

[0026] At the same time, the minimum thickness H of the welding part is set to be greater than or equal to one tenth of the hole side wall thickness D, and less than or equal to nine tenths of the side wall thickness D, so that the minimum thickness H of the welding part is very reasonable. It will not make the minimum thickness too thin because the aperture d1 is less than one tenth of the hole side wall thickness D, which is beneficial to improving the sealing effect of the pressure difference liquid hole and improving the stability of the battery operation; nor will it greatly increase the difficulty of controlling the laser because the aperture d1 is greater than nine tenths of the hole side wall thickness D, which is beneficial to reducing the technical difficulty of battery production, reducing production costs, and improving production efficiency.

[0027] Furthermore, because the thickness of the welded portion of the pressure differential fluid hole is less than the thickness of the battery's metal casing, when the battery short-circuits or an internal malfunction occurs, a large amount of gas is generated inside the battery. At this time, the gas inside the battery will preferentially break through the welded portion, allowing the internal gas to be released. This prevents the battery from expanding and exploding due to excessive internal gas in the event of a short circuit or internal malfunction. In other words, the battery of the present application can utilize the welded portion of the pressure differential fluid hole to form a natural safety valve, thereby preventing the risk of explosion caused by the inability of the battery to discharge a large amount of gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0029] Figure 1 A schematic diagram of the cross-sectional structure of a battery according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of the cross-sectional structure of another embodiment of a battery of the present invention;

[0031] Figure 3 is a schematic cross-sectional view of another embodiment of a battery of the present invention;

[0032] Figure 4 A schematic cross-sectional view of another embodiment of a battery according to the present invention;

[0033] Figure 5 A schematic cross-sectional view of another embodiment of a battery according to the present invention;

[0034] Figure 6 A schematic diagram of the internal structure of a battery according to an embodiment of the present invention;

[0035] Figure 7 is a schematic structural diagram of another embodiment of a battery of the present invention;

[0036] Figure 8 for Figure 7 Enlarged schematic diagram of point P in the middle.

[0037] Description of Figure Numbers:

[0038] Label name Label name 100 Melting area 200 Welding section 210 First end face 220 Second end face 300 Pressure difference through liquid hole 410 Positive metal shell 420 Negative metal shell 430 battery cells 440 Sealed insulator 450 Sealed cavity

[0039] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0042] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel solutions. Taking "A and / or B as an example", it includes solution A, or solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] The present invention provides a battery, which is exemplified by a small-sized button battery, a mobile phone battery, a toroidal battery, etc. The structure and principle of the battery are described in detail below.

[0044] Reference Figures 1 to 6 , a battery, the battery comprising a positive electrode metal shell 410, a negative electrode metal shell 420, a sealing insulator 440 and a battery cell 430;

[0045] The positive electrode metal shell 410, the negative electrode metal shell 420 and the sealed insulator 440 form a sealed cavity 450, and the battery cell 430 is located in the sealed cavity 450;

[0046] The positive electrode shell and / or the negative electrode metal shell 420 has a welded portion, which is formed by the side wall of the melt pressure differential liquid hole 300, wherein the pressure differential liquid hole 300 is used for electrolyte to enter or flow out of the sealed cavity 450 under the working condition that there is a pressure difference between the sealed cavity 450 and the outside world, and the aperture d1 of the pressure differential liquid hole 300 is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the thickness D of the hole side wall;

[0047] The thickness of the welding portion is smaller than the thickness D of the hole sidewall at the corresponding position thereof, and the radial dimension of the welding portion is larger than the radial dimension of the pressure differential liquid hole 300;

[0048] The middle portion of the welding portion is recessed from the outside of the battery shell toward the inside of the sealed cavity 450 , and the minimum thickness H of the welding portion is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the side wall thickness.

[0049] Specifically, in this embodiment, the overall shape of the positive metal shell 410 and the negative metal shell 420 can be many, and the two are enclosed to form the shell of the battery. The sealing insulator 440 is arranged at the connection between the positive metal shell 410 and the negative metal shell 420, so that the two are insulated and matched. The overall shell of the battery can be many, such as a round cake shape, an elliptical cake shape, a rectangular parallelepiped shape, etc., and the battery is described as a round cake shape. Preferably, in order to reduce the thickness of the battery shell and increase the service life of the battery, the metal material of the positive metal shell 410 and the negative metal shell 420 in this application can be stainless steel, and the specific stainless steel can be 304 stainless steel or 316 stainless steel.

[0050] During the battery production process, under a vacuum environment, the electrolyte is allowed to enter the closed cavity through the pressure differential liquid hole 300, and then the pressure differential liquid hole 300 is welded and sealed using a laser. The weld can be formed on the positive metal shell 410, the negative metal shell 420, or both the positive metal shell 410 and the negative metal shell 420. Reflecting on the battery structure, the weld can be formed at one or more locations on the top, bottom, and surrounding side walls of the battery. The weld is formed during the process of laser melting the side walls of the pressure differential liquid hole 300, allowing the molten metal liquid to flow into the pressure differential liquid hole 300 and cool and solidify to seal the pressure differential liquid hole 300. The sidewalls of the housing should not be too thick. This will increase the weight of the battery, increase material consumption, and make it difficult to maintain both the overall volume of the battery and the internal capacity of the battery (the volume of the enclosed cavity). (Excessively thick sidewalls will compress the space in the enclosed cavity or increase the overall volume of the electronics. Compressing the space in the enclosed cavity will reduce the volume of the battery cell 430, resulting in a decrease in the battery capacity. Increasing the overall volume of the electronics will limit the battery's use.) The sidewalls of the housing should not be too thin. This will affect the strength of the housing, reduce its load-bearing capacity, and make the housing susceptible to rupture or damage, which is detrimental to the stability and reliability of the battery. Therefore, the thickness of the battery shell is set to 0.08mm-0.25mm, which can be 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.165mm, 0.17mm, 0.175mm, 0.18mm, 0.19mm, 0.195mm, 0.2mm, 0.21mm, 0.215mm, 0.22mm, 0.23mm, 0.235mm, 0.24mm. Preferably, in order to ensure that the battery is not easily deformed and the pressure differential liquid hole 300 can be well sealed during the subsequent welding process, the thickness of the battery shell is greater than 0.15mm.

[0051] The pressure differential liquid hole 300 is used to allow electrolyte to enter or flow out of the sealed cavity 450. The electrolyte needs to flow into or out of the sealed cavity 450 when there is an air pressure difference between the sealed cavity 450 and the outside. In other words, the electrolyte cannot enter or flow out of the sealed cavity under the action of its own gravity, nor is it suitable to be transported or withdrawn from the sealed cavity by a transport mechanism. Instead, it needs to be acted upon by an external force (air pressure or hydraulic pressure) to enter or flow out of the sealed cavity. For example, in a vacuum environment, there is a large air pressure difference between the sealed cavity and its outside; for example, immersing the battery in electrolyte creates a large hydraulic pressure difference between the sealed cavity and its outside. The reason why the electrolyte needs to be acted upon by an external force (air pressure or hydraulic pressure) to enter or flow out of the sealed cavity is that the aperture of the pressure differential liquid hole 300 is very small. Its aperture d1 is greater than or equal to one-tenth of the thickness D of the hole sidewall and less than or equal to nine-tenths of the thickness D of the hole sidewall. When the electrolyte flows near the pressure differential liquid hole 300, the outer wall of the shell and the side wall of the pressure differential liquid hole 300 will give the electrolyte a very strong adhesion force. This adhesion force is far greater than the gravity of the electrolyte around the pressure differential liquid hole 300, making it impossible for the electrolyte to pass through the pressure differential liquid hole 300 under the action of its own gravity. Compared with traditional batteries, the pressure differential liquid hole 300 of the battery of the present application allows the electrolyte to slowly enter the battery under the action of pressure, and then allows the electrolyte to quickly and evenly enter the positive and negative electrode materials of the battery cell. Because the electrolyte is under positive pressure when entering the battery, that is, the electrolyte can only enter the battery shell in one direction, it can prevent the electrolyte from volatilizing after entering the battery, thereby reducing the amount of electrolyte loss during the manufacturing process and the volatilization of volatile substances in the electrolyte, which changes the electrolyte concentration and thus affects the battery performance. Furthermore, after the electrolyte enters the interior of the battery and fully infiltrates the battery cell, if there is residual electrolyte, the residual electrolyte can come out through the pressure difference liquid hole 300. When the residual electrolyte comes out, the electrolyte can form a relatively sealed state with the pressure difference liquid hole 300. This can ensure that the electrolyte that comes out first is the residual electrolyte rather than the electrolyte that has infiltrated the positive and negative materials of the battery cell, and can effectively avoid the volatilization of the electrolyte when the residual electrolyte is extracted.

[0052] It is worth noting that the aperture of the pressure differential liquid hole 300 should not be less than one tenth of the hole side wall thickness D. If the aperture of the pressure differential liquid hole 300 is too small, the pressure required for the electrolyte to pass through the pressure differential liquid hole 300 will be too large. Such a large pressure will also act on the shell, which may cause the side wall of the shell to deform and affect the stability of the battery; at the same time, the aperture of the pressure differential liquid hole 300 should not be larger than nine tenths of the hole side wall thickness D. If the aperture of the pressure differential liquid hole 300 is too large, it will be unfavorable for the melting and sealing of the pressure differential liquid hole 300, so that more shells (shells around the pressure differential liquid hole 300) need to be melted to seal the pressure differential liquid hole 300, which is not conducive to maintaining the shell's anti-deformation strength. Too large an aperture is also not conducive to completely sealing the pressure differential liquid hole 300.

[0053] In other embodiments, the diameter d1 of the pressure differential liquid hole 300 is 0.01 mm to 0.1 mm, and may be 0.02 mm, 0.03 mm, 0.04 mm, 0.45 mm, 0.05 mm, 0.055 mm, 0.057 mm, 0.06 mm, 0.07 mm, 0.08 mm, or 0.09 mm. By limiting the diameter d1 of the pressure differential liquid hole 300 to 0.01 mm to 0.1 mm, the diameter of the pressure differential liquid hole 300 is more reasonable, making it well-suited for sealing via laser fusion. This helps reduce the process requirements for battery production and improves battery stability and reliability. Because the radial dimension of the pressure differential liquid hole is very small, it does not affect the overall strength of the metal shell, thereby ensuring the overall strength of the metal shell while also meeting the requirements for the inflow and outflow of electrolyte.

[0054] During the formation of the weld, the shell surrounding the differential pressure hole 300 melts and flows into the hole 300, causing the shell thickness around the hole 300 to be less than its original thickness, thereby causing the weld to be recessed into the sealed cavity 450. The weld's minimum thickness H is located within the differential pressure hole 300, serving to seal the portion of the hole 300. This minimum thickness H cannot be too small. If it is less than one-tenth the hole sidewall thickness D, this portion is too thin, exhibiting weak deformation resistance and being easily damaged during subsequent processing, transportation, and use, which is detrimental to the battery's stability. The minimum thickness H cannot be too large. When the minimum thickness H is greater than nine-tenths of the hole sidewall thickness D, more shells (shells around the pressure differential liquid hole 300) need to be melted to block the pressure differential liquid hole 300, which is not conducive to maintaining the shell's anti-deformation strength. In addition, if the minimum thickness H is to be greater than nine-tenths of the hole sidewall thickness D, the thickness of the melted shell is less than one-tenth of its own thickness D. That is, at this time, it is necessary to use metal shell material less than one-tenth of the thickness D to fill it. The depth greater than nine-tenths of the thickness D greatly increases the difficulty of controlling laser melting, which is not conducive to improving production efficiency and reducing production costs. Furthermore, since the thickness of the weld of the pressure differential liquid hole 300 is less than the thickness of the battery metal shell, when the battery short-circuits or a fault occurs inside the battery, a large amount of gas is generated inside the battery. At this time, the gas inside the battery will first break through the weld, allowing the internal gas to be released, avoiding the danger of excessive internal gas causing battery expansion and explosion when the battery short-circuits or the battery fails. That is to say, the battery of the present application can form a natural safety valve by utilizing the welding portion of the pressure difference through the liquid hole 300, thereby avoiding the risk of explosion caused by a large amount of gas inside the battery being unable to be discharged.

[0055] In this embodiment, a welding portion is provided on the positive electrode metal shell 410 and / or the negative electrode metal shell 420, and the welding portion is formed by the side wall of the molten pressure difference liquid hole 300, wherein the pressure difference liquid hole 300 is used for the electrolyte to enter or flow out of the closed cavity 450 under the working condition that there is a pressure difference between the closed cavity 450 and the outside world. At the same time, the aperture d1 of the pressure difference liquid hole 300 is set to be greater than or equal to one tenth of the hole side wall thickness D and less than or equal to nine tenths of the hole side wall thickness D, so that the pressure difference The aperture 300 has a very suitable diameter. Because the aperture diameter d1 is less than one-tenth of the hole sidewall thickness D, the pressure required for the electrolyte to pass through the pressure differential liquid hole 300 is not too high. This avoids the risk of the shell sidewall deforming due to excessive pressure, which is beneficial to improving the stability of the battery. Also, because the aperture diameter d1 is greater than nine-tenths of the hole sidewall thickness D, too much metal shell needs to be melted to fill the pressure differential liquid hole 300. This reduces production difficulty, improves the reliability of the melt seal, and enhances the stability of the battery.

[0056] At the same time, the minimum thickness H of the welding portion is set to be greater than or equal to one tenth of the hole side wall thickness D, and less than or equal to nine tenths of the side wall thickness D, so that the minimum thickness H of the welding portion is very reasonable. It will not make the minimum thickness too thin because the aperture d1 is less than one tenth of the hole side wall thickness D, which is beneficial to improving the sealing effect of the pressure difference liquid hole 300 and improving the stability of the battery operation; nor will it greatly increase the difficulty of controlling the laser because the aperture d1 is greater than nine tenths of the hole side wall thickness D, which is beneficial to reducing the technical difficulty of battery production, reducing production costs, and improving production efficiency.

[0057] In some embodiments, the weld includes a melting portion 100 and a welded portion 200. The melting portion 100 is located outside the differential pressure liquid hole 300, while the welded portion 200 is located inside the differential pressure liquid hole 300 to seal the hole 300. Specifically, in this embodiment, the melting portion 100 is a groove located at the location where the shell melted during the welding process. The groove has an overall bowl-like shape, with sidewalls extending upward from the bottom. During the melting process of the metal shell surrounding the differential pressure liquid hole 300, a portion of the melt flows into the differential pressure liquid hole 300 in a liquid state, gradually cooling and solidifying to form the welded portion 200. The welded portion 200, formed by the flow and cooling of the liquid metal into the differential pressure liquid hole, has an overall cylindrical shape. The end surface of the welded portion 200 adjacent to the melting portion 100 is concave, while the end distal to the melting portion 100 protrudes toward the sealed cavity 450. High-temperature molten metal gradually flows from the periphery of the pressure differential liquid hole 300 along its sidewalls into the pressure differential liquid hole 300. As the molten metal flows along the hole's sidewalls, it gradually cools, its fluidity gradually weakening. When the adhesion between the molten metal and the hole's sidewalls becomes greater than the weight of the molten metal, the molten metal stops flowing downward, and newly melted molten metal covers the stagnant metal and flows toward the center of the pressure differential liquid hole 300. Because the temperature of the stagnant metal is higher than that of the hole's sidewalls, the newly melted metal can continue to flow downward for a certain distance, causing the bottom of the weld 200 to bulge toward the sealed cavity 450. When the surrounding molten metal merges, the newly melted metal flowing downward is resisted by the already merged liquid, preventing it from flowing downward and instead continuously filling the pressure differential liquid hole 300 upward until it contacts the unmelted hole's sidewalls. Since the metal liquid flows from the periphery to the middle of the pressure differential liquid hole 300 , the middle is the last filling position, so the end surface of the welding part 200 away from the closed cavity 450 (close to the melting part 100 ) is also concave toward the closed cavity 450 .

[0058] It is worth noting that the specific concave position of the first end surface 210 of the weld portion 200 near the molten portion 100 and the specific convex position of the second end surface 220 near the sealed cavity 450 can vary, depending on the specific welding method and the position of the laser center. The following describes several specific situations: a single weld completes the melt seal; the laser spot area is larger than the area of ​​the pressure differential liquid hole 300; the laser center is located near the center of the pressure differential liquid hole 300 (or even coincides with it); the laser center deviates from the center of the pressure differential hole; and multiple welds complete the melt seal.

[0059] Reference Figure 1 In the first operating condition, a single weld completes the melt seal. The laser's center is located at the center of the differential pressure hole 300, and the laser spot covers the entire hole 300. At this point, because the laser's energy is higher in the center, it gradually decreases as it diffuses toward the surrounding areas. The laser's center coincides with the center of the differential pressure hole 300, resulting in comparable laser intensity around the hole 300 (the laser energy intensity on the metal shell surrounding the hole 300 is symmetrical about the hole's center). This results in a comparable depth and range of melting of the metal shell surrounding the hole 300, forming the molten zone 100 into a solid of revolution (similar to an inverted frustum of a cone), with the axis of revolution of the molten zone 100 being the central axis of the hole 300. During the formation of the weld 200, the laser's center corresponds to a higher energy location, resulting in a higher temperature for the liquid metal near the laser's center. Consequently, the location of final solidification is the location corresponding to the laser's center, and the surrounding liquid metal converges at the location corresponding to the laser's center. In this way, the concave position of the first end surface 210 and the convex position of the second end surface 220 both correspond to the center position of the pressure difference liquid hole 300 .

[0060] Reference Figure 2 In the second operating condition, the melt seal is completed in a single weld. The center of the laser beam is offset from the center of the differential pressure flow hole 300, and the laser spot covers the entire differential pressure flow hole 300. This operating condition differs from the previous one in that the centerline of the laser beam is offset from the central axis of the differential pressure flow hole 300. In this case, the laser energy acting on the metal shell surrounding the differential pressure flow hole 300 is not symmetrical about the center of the differential pressure flow hole 300. The metal shell closer to the center of the laser beam receives more laser energy, resulting in faster melting of the metal shell at that location, higher temperature of the molten metal liquid, better fluidity, and a greater thickness of the metal shell that can be melted. This shifts the location where the metal fluids converge closer to the center of the laser beam. Consequently, the recessed positions of the first end surface 210 and the second end surface 220 correspond to the center of the laser beam, offset from the center of the differential pressure flow hole 300.

[0061] Reference Figure 3The third operating condition involves multiple welding operations, or simultaneous welding with multiple laser spots. During welding, the single laser spot does not cover the entire differential pressure liquid hole 300. In the case of multiple welding with a single laser, the laser welding spots are arranged circumferentially around the differential pressure liquid hole 300. After the first weld, portions of the differential pressure liquid hole 300 are blocked. During the second and subsequent welds, some of the liquid metal will block more differential pressure liquid holes 300, while some will flow onto the previously welded portion 200, forming a stacked structure. When the laser energy for each weld is comparable, and the center of the laser beam is located on the same circumference during multiple welds, with the center of the circumference located on the axis of the differential pressure liquid hole 300, the protruding position of the second end surface 220 is located on the axis of the differential pressure liquid hole 300. If the center of the circumference deviates from the axis of the differential pressure liquid hole 300, the protruding position of the second end surface 220 will deviate from the axis of the differential pressure liquid hole 300.

[0062] In some embodiments, to improve welding efficiency, the laser intensity is high, causing a portion of the metal shell to melt and dissipate as gas in the space surrounding the weld. This ensures that the volume of the molten portion 100 is greater than or equal to the volume of the welded portion 200. Regarding the volume ratio of the molten portion 100 to the welded portion 200, the higher the laser intensity, the more metal shell is melted, and the larger the volume of the molten portion 100. However, the amount of metal fluid that can flow into the pressure differential liquid hole 300 is limited by space. After a certain increase in laser intensity, it ceases to increase, and the excess metal liquid is vaporized. When the laser intensity reaches a certain value, the metal shell may be penetrated, preventing the desired fusion welding. Therefore, the laser intensity cannot be too high, which also limits the volume ratio of the molten portion 100 to the welded portion 200. The volume ratio of the molten portion 100 to the welded portion 200 cannot be too small. To achieve a smaller ratio, the laser energy must be low. However, a low-energy laser alone takes a very long time to melt the metal shell, which is not conducive to improving welding efficiency. Therefore, the volume ratio of the molten portion 100 to the weld portion 200 is 1.2-3, and can be 1.3, 1.5, 1.7, 1.8, 1.9, 1.95, 2.0, 2.1, 2.2, 2.3, 2.5, 2.7, 2.9, etc. When the volume ratio of the molten portion 100 to the weld portion 200 is 1.2-3, the welding efficiency can be guaranteed without penetrating the metal shell, thereby ensuring the safety and stability of the battery.

[0063] In some embodiments, the ratio (L1:L2) between the radial dimension L1 of the molten zone 100 extending radially along the pressure differential liquid hole 300 and the axial dimension L2 of the molten zone 100 extending axially along the pressure differential liquid hole 300 is 0.75 to 2. Specifically, in this embodiment, the ratio of the radial dimension to the depth of the molten zone 100 is related to the transverse and longitudinal attenuation rates of the laser. When the transverse attenuation rate of the laser is greater than the longitudinal attenuation rate, the radial dimension L1 of the molten zone 100 is smaller than the axial dimension L2 of the molten zone 100; when the longitudinal attenuation rate of the laser is greater than the transverse attenuation rate, the radial dimension L1 of the molten zone 100 is larger than the axial dimension L2 of the molten zone 100. It is worth noting that the ratio (L1:L2) between the radial dimension L1 and the axial dimension L2 should be neither too large nor too small. If the L1:L2 ratio is too small, the transverse attenuation rate is much greater than the longitudinal attenuation rate, making the laser difficult to control. Similarly, if the L1:L2 ratio is too large, the transverse attenuation rate is much less than the longitudinal attenuation rate, making the laser difficult to control. Furthermore, if the ratio L1:L2 between the radial dimension L1 and the axial dimension L2 is too large or too small, the structural stability of the molten portion 100 will be reduced, which is not conducive to the stable operation of the battery.

[0064] The ratio of the radial dimension L1 of the molten portion 100 extending radially along the differential pressure liquid hole 300 to the radius d1 / 2 of the differential pressure liquid hole 300 is 1 to 5. It is worth noting that the ratio of the radial dimension L1 to the radius d1 / 2 of the differential pressure liquid hole 300 reflects the relationship between the size of the melted metal shell and the size of the differential pressure liquid hole 300 in the radial direction of the differential pressure liquid hole 300. A large ratio between the two should not be too large, as this indicates that the radial dimension of the melted metal shell is too large. When the radial dimension of the melted shell is greater than 5 times the radial dimension of the differential pressure liquid hole 300, the area of ​​the melted metal shell is large, which can easily affect the stability of the overall battery structure. When the radial dimension of the melted shell is less than 1 times the radial dimension of the differential pressure liquid hole 300, the area of ​​the melted metal shell is small, requiring a larger depth L2 of the molten portion 100 to ensure melt filling of the differential pressure liquid hole 300. This will make the thickness of the metal shell around the weld 200 too thin, affecting the reliability and stability of the weld 200. In some embodiments, considering the portion of the metal shell melted by the laser into a gaseous state, the depth L2 of the molten portion 100 is required to be greater.

[0065] In some embodiments, to further improve the stability of the weld 200, the ratio (L2:D) between the axial dimension L2 of the molten portion 100 extending along the axial direction of the differential pressure liquid hole 300 and the hole depth D of the differential pressure liquid hole 300 is 1 / 3 to 2 / 3. Specifically, in this embodiment, the ratio (L2:D) between the axial dimension L2 and the hole depth D of the differential pressure liquid hole 300 reflects the position of the weld 200 within the differential pressure liquid hole 300. The distance between the weld 200 and the top of the battery should not be too short. If it is too short, the thickness of the molten portion 100 will be smaller to fill more differential pressure liquid holes 300, which will make the laser melting process very complex and difficult, and increase the cost of electrolyte injection. The distance between the welding part 200 and the top of the battery should not be too long. If it is too long, the welding part 200 will be too close to the closed cavity 450, which will easily lead to structural instability of the welding part 200 when subjected to external force, which will make the bearing capacity of the welding part 200 and the battery weaker and the stability poorer.

[0066] In some embodiments, to improve the sealing and stability of the weld 200, the battery further includes a sealing layer, which is filled above the melting portion 100 and the weld 200 so that the top surface of the sealing layer is flush with the outer surface of the housing. The sealing layer can be an insulating adhesive layer. Liquid adhesive flows into the melting portion 100, solidifies at room temperature, and covers the weld 200. In this way, the weld 200 can be covered and protected by the insulating adhesive layer, preventing external environmental factors such as dust and water from affecting the stability of the weld 200.

[0067] The present invention also provides an electronic product, comprising a device body and a battery, wherein the battery is electrically connected to the device body to provide electrical energy to the device body. The specific structure of the battery is described with reference to the above-mentioned embodiments. Since the present battery adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, and will not be described in detail here. The battery can be configured as a button battery, which is mainly used in electronic products to provide electrical energy for electronic products. Among them, the electronic products can be headphones, watches, etc., which use relatively low voltage electronic products.

[0068] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A battery, characterized in that: The battery comprises a positive electrode metal shell, a negative electrode metal shell, a sealed insulator and a battery cell; The positive electrode metal shell, the negative electrode metal shell and the sealed insulator form a sealed cavity, and the battery cell is located in the sealed cavity; The positive electrode metal shell and / or the negative electrode metal shell has a welding portion, the welding portion is formed by the side wall of the molten pressure differential liquid hole, wherein the pressure differential liquid hole is used for electrolyte to enter or flow out of the closed cavity under the working condition that there is a pressure difference between the closed cavity and the outside, and the aperture d1 of the pressure differential liquid hole is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the thickness D of the hole side wall; The thickness of the welding portion is smaller than the thickness D of the hole side wall at the corresponding position thereof, and the radial dimension of the welding portion is larger than the radial dimension of the pressure differential liquid hole; The middle portion of the welding portion is recessed from the outside of the battery shell toward the inside of the sealed cavity, and the minimum thickness H of the welding portion is greater than or equal to one tenth of the thickness D of the hole side wall and less than or equal to nine tenths of the thickness of the side wall; The welding portion includes a melting portion and a welding portion, wherein the melting portion is located outside the pressure differential liquid hole, and the welding portion is located inside the pressure differential liquid hole for sealing the pressure differential liquid hole; The volume of the molten portion is greater than or equal to the volume of the weld portion, and the volume ratio of the molten portion to the weld portion is 1.2 to 3; A ratio L1:L2 between a radial dimension L1 of the fusion portion extending in the radial direction of the differential pressure liquid hole and an axial dimension L2 of the fusion portion extending in the axial direction of the differential pressure liquid hole is 0.75-2.

2. The battery according to claim 1, wherein The welding part is arranged in an end column shape, the end surface of the welding part adjacent to the melting part is arranged in a concave shape, and the end away from the melting part is convex toward the closed cavity.

3. The battery according to claim 1, wherein The ratio L2:D between the axial dimension L2 of the molten portion extending in the axial direction of the differential pressure liquid hole and the hole depth D of the differential pressure liquid hole is 1 / 3 to 2 / 3.

4. The battery according to claim 1, wherein The ratio between the radial dimension L1 of the molten portion extending in the radial direction of the differential pressure liquid hole and the radius d1 / 2 of the differential pressure liquid hole is 1 to 5.

5. The battery according to claim 1, wherein The battery further includes a sealing layer, which is filled above the melting portion and the welded portion so that a top surface of the sealing layer is flush with an outer surface of the shell.

6. The battery according to claim 1, wherein The aperture d1 of the pressure differential liquid hole is 0.01mm to 0.1mm; And / or, the thickness of the shell is 0.08 mm to 0.25 mm.

7. An electronic product, characterized in that: The device comprises a device body and a battery according to any one of claims 1 to 6, wherein the battery is electrically connected to the device body to provide electrical energy to the device body.

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