Sealing plate for battery and battery using the same

Abstract

An object of the present invention is to provide a sealing plate for a battery, comprising an upper cover, a lower cover and a valve body, characterized in that the upper cover has an annular convex portion and an edge portion formed around the convex portion, the convex portion is hollow, and a plurality of venting holes are formed on the convex portion; the lower cover has a cover bottom, the edge portion of the upper cover and the cover bottom of the lower cover are combined by spot welding, the lower cover has a plurality of valve holes, the plurality of valve holes are arranged in a ring corresponding to the annular convex portion, and a valve body covering the plurality of valve holes is provided in a space formed by the hollow convex portion and the cover bottom of the lower cover.

Description

Technical Field

[0001] The present invention relates to a battery sealing plate and a battery having the battery sealing plate. Background Art

[0002] Batteries are generally categorized as physical batteries and chemical batteries. Chemical batteries convert chemical energy into electrical energy through a chemical reaction between positive and negative electrodes. Batteries are also categorized as primary and secondary batteries based on their reusability. Primary batteries are those that cannot be recharged, only discharged, such as zinc-manganese, alkaline dry cells, lithium button cells, and lithium-ion batteries. Secondary batteries are those that can be repeatedly charged and discharged, such as lead-acid, nickel-cadmium, nickel-metal hydride, lithium-ion, lithium polymer, fuel, zinc, aluminum, and magnesium-air batteries.

[0003] With the development of electronic products, especially the popularity of mobile and handheld electronic products in recent years, secondary batteries (such as nickel-cadmium, nickel-metal hydride, and lithium-ion batteries) have experienced rapid growth due to their ability to be repeatedly charged and discharged, their ease of use, high capacity, and compact size and portability. This has led to higher demands on these batteries during use, such as high capacity, high power, and high safety. Secondary batteries (using nickel-metal hydride as an example) generally consist of a metal housing, sealing components (sealing plate, positive electrode cap, exhaust valve), leads, and a plate assembly consisting of a rolled positive electrode, insulating paper, and negative electrode, sealed within a sealed cavity formed by the metal housing and sealing plate, along with an electrolyte that immerses the plate assembly. The assembly process of nickel-metal hydride batteries is generally as follows: one end of the lead is first welded to the positive plate, then wound into a group with the negative plate and insulating paper through a winding process. The group is then inserted into the metal shell through a shell insertion process. After a groove insertion process, a concave ring is formed on the shell to fix the group. Then the electrolyte is injected, and the other end of the lead is welded to the sealing plate. Finally, the sealing process is completed to form a complete battery.

[0004] To meet the demand for high-capacity batteries, increasing the width of the plates to increase the active material and thus the battery's capacity is generally done. However, this results in a dramatic reduction in the remaining space within the battery. During charging and discharging, the reaction between the electrodes and the electrolyte decomposes the electrolyte, generating gas. When the gas reaches a certain pressure, the internal pressure is controlled by a vent valve, forcing the gas to escape through the vent holes at the bottom of the sealing plate, thereby ensuring battery safety. Under certain conditions, such as an external short circuit, the battery temperature and internal pressure can rise sharply. If this pressure is not released in a timely manner, the battery may explode or pose a safety risk. Therefore, it is necessary to quickly release the gas from the battery before it ruptures.

[0005] Therefore, as a technology to quickly release the gas inside the battery to the outside of the battery, various schemes such as setting a sealing plate as a vent valve in the sealing component of the battery have been proposed. The structure of the sealing plate used in the existing cylindrical battery is shown in the figure. Figure 6 shown.

[0006] The sealing plate consists of an upper cover 51, a lower cover 53, and a valve body 7 between them. The upper cover 51 has a cylindrical convex portion 6 protruding from its center, serving as the positive output terminal. The upper cover 51 also has a flange surrounding the entire circumference of the convex portion 6. A square vent hole 50, approximately 1 mm in length, is formed at the bottom of the convex portion 6, extending all the way to the flange.

[0007] The lower cover 53 has a valve hole 8 with a diameter of about 1.5 mm at its center, and the valve hole 8 is closed by the valve body 7. The flange portion of the lower cover 53 and the upper cover 51 are connected by spot welding.

[0008] Typically, the upper cover 51 and lower cover 53 are manufactured by repeatedly stamping and nickel-plating steel sheets approximately 0.5 mm thick. The thickness of the steel sheets used for the upper cover 51 and lower cover 53 can vary; for example, the upper cover 51 can be 0.4 mm thick, while the lower cover 53 can be 0.6 mm thick. The valve body 7 is a square, cylindrical rubber component. This rubber valve body 7 seals the valve hole 8. When the operating pressure of the gas generated within the battery exceeds a specified threshold, the gas pressure compresses and deforms the rubber valve body 7, releasing the seal on the valve hole 8. The gas then escapes from the valve hole 8 into the space enclosed by the upper and lower covers 51, 53, and the rubber valve body 7, and is then discharged to the outside of the battery case through multiple vent holes 50. In this way, the sealing plate functions as a vent valve, discharging abnormal gases from the battery case.

[0009] However, during actual battery use, the convex portion 6 of the sealing plate (the positive terminal) is susceptible to impact, such as when dropped on the ground. This impact can cause local deformation of the convex portion 6, forcing the rectangular cylindrical rubber valve body 7 to deform within the convex portion 6 and maintain this deformed state. This compressive deformation, or the compression rate, of the rubber valve body 7 increases. Consequently, even when the operating pressure of the gas generated within the battery exceeds a specified threshold, this pressure may not be able to cause the rubber valve body 7, which has a high compression rate, to contract, preventing smooth gas discharge. In this case, the battery is prone to explosion, creating a serious safety issue.

[0010] Alternatively, the gas pressure within the battery barely compresses the rubber valve body 7, but only a small amount of gas is released into the space enclosed by the upper cover 51, the lower cover 53, and the rubber valve body 7, and then out of the battery case 1 through the vent hole 50. Even in this case, since sufficient gas cannot be released out of the battery case, the safety of the battery cannot be guaranteed.

[0011] Patent Document 1: Chinese Invention Patent Application Publication No. CN1363119A Summary of the Invention

[0012] An object of the present invention is to provide a sealing plate for a battery and a battery having the sealing plate, which can ensure the safety and reliability of the battery even when the sealing plate is deformed, thereby improving the safety of the battery.

[0013] The battery sealing plate of the present invention comprises an upper cover, a lower cover and a valve body, and is characterized in that the upper cover has an annular convex portion and an edge portion formed around the convex portion, the convex portion is hollow, and a plurality of vent holes are formed on the convex portion; the lower cover has a cover bottom, the bent portion and the edge portion of the upper cover are joined by spot welding, the lower cover has a plurality of valve holes, the plurality of valve holes are arranged in a ring corresponding to the annular convex portion, and a valve body covering the plurality of valve holes is provided in a space formed by the hollow convex portion and the cover bottom of the lower cover.

[0014] According to the battery having this structure, the deformation resistance of the convex portion can be improved, and gas can be discharged smoothly, thereby ensuring the safety of the battery.

[0015] Alternatively, the lower cover further has a bent portion formed around the cover bottom, and the valve body is formed in a ring shape.

[0016] Thus, the upper cover can be positioned on the cover bottom of the lower cover through the bent portion of the lower cover, and the annular valve body corresponds to the annular convex portion of the upper cover and closes the annular valve hole formed on the lower cover.

[0017] Alternatively, the annular convex portion is formed into a hollow convex shape by a cylindrical inner wall and a cylindrical outer wall having different diameters and a top wall connecting the top ends of the two side walls, thereby forming a space for accommodating the valve body.

[0018] Alternatively, the plurality of air release holes may be respectively provided on the cylindrical inner wall and the cylindrical outer wall, thereby enabling the gas with uncertain discharge directions to be discharged smoothly from both the cylindrical inner wall and the cylindrical outer wall.

[0019] Alternatively, a plurality of vent holes may be formed at equal intervals around the cylindrical outer wall and the cylindrical inner wall on the lower portion of each of the cylindrical outer wall and the cylindrical inner wall, wherein the vent holes formed on the lower portion of the cylindrical outer wall extend to the edge of the upper cover. This allows for smoother gas discharge.

[0020] Alternatively, eight valve holes may be formed on the lower cover, six air release holes may be formed on the cylindrical outer wall, and four air release holes may be formed on the cylindrical inner wall.

[0021] Alternatively, a radius of the ring formed by the plurality of valve holes is half of the sum of the radii of the cylindrical outer wall and the cylindrical inner wall.

[0022] The battery of the present invention is characterized by comprising: a case having an opening; an electrode plate assembly including a positive electrode plate and a negative electrode plate inserted into the case; and the above-mentioned battery sealing plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 4 is a cross-sectional view of a battery of the present invention.

[0024] Figure 2 It is a three-dimensional view of the sealing plate of the present invention.

[0025] Figure 3A This is a three-dimensional picture of the upper cover of the sealing plate. Figure 3B A top view of the upper cover of the sealing plate.

[0026] Figure 4A This is a three-dimensional diagram of the lower cover of the sealing plate. Figure 4B This is a top view of the lower cover of the sealing plate.

[0027] Figure 5A It is a three-dimensional diagram of the annular valve body. Figure 5B It is a top view of the annular valve body.

[0028] Figure 6 A cross-sectional view of a battery according to the prior art.

[0029] Explanation of symbols

[0030] 1 Upper cover

[0031] 2 Lower cover

[0032] 3 Valve body

[0033] 4 Battery Case

[0034] 41 Lead

[0035] 42 Sealing parts

[0036] 5-plate group

[0037] 10 convex part

[0038] 11 Top wall

[0039] 12 Cylindrical inner wall

[0040] 13 Cylindrical outer wall

[0041] 14 vent holes

[0042] 15 vent hole

[0043] 16 Welding recess

[0044] 17 Edge

[0045] 21 Cover

[0046] 22 bending part

[0047] 23 valve hole

[0048] 6 convex part

[0049] 7 Valve body

[0050] 8 valve holes

[0051] 50 vent hole

[0052] 51 Upper cover

[0053] 53 lower cover DETAILED DESCRIPTION

[0054] The following uses the attached Figures 1 to 6 The specific embodiment of the present invention is described below. In this embodiment, AA batteries are used as an example for description.

[0055] Figure 1 is a cross-sectional view of a battery according to the present invention.

[0056] Figure 1 In the embodiment, battery A comprises a bottomed cylindrical battery case 4, an electrode assembly 5 immersed in an electrolyte contained in the battery case 4, and a sealing plate 1A that seals the opening of the battery case 4. The opening edge of the battery case 4 and the sealing plate 1A are airtightly connected via a sealing member 42 disposed along the opening edge. The battery case 4 is cylindrical in this embodiment, but may also be a battery case of another shape, such as a square.

[0057] The sealing plate 1A includes an upper cover 1 , a lower cover 2 and a valve body 3 .

[0058] Figure 2 It means that it consists of upper cover 1, lower cover 2 and valve body 3 ( Figure 2 A perspective view of the sealing plate 1A assembled with the sealing plate 1A (not shown).

[0059] Below, refer to Figures 3A to 5B The upper cover 1 , the lower cover 2 , and the valve body 3 of the sealing plate 1A will be described separately.

[0060] like Figure 3A As shown, the upper cover 1 is a cover bottom having an annular convex portion 10 at the center of the bottom surface of the cover bottom and an edge portion 17 formed around the outer periphery of the convex portion 10 .

[0061] The annular convex portion 10 is composed of a cylindrical inner wall 12 with a radius r2, centered at the center of the circle of the upper cover 1, and a cylindrical outer wall 13 with a radius r1, rising from the bottom surface of the upper cover 1, and a top wall 11 connecting the upper end edge of the cylindrical inner wall 12 and the upper end edge of the cylindrical outer wall 13. Here, r1>r2.

[0062] The height of the cylindrical inner wall 12 and the cylindrical outer wall 13 rising from the bottom surface of the upper cover 1 is about 1.6 to 1.7 mm. The annular convex portion 10 composed of the cylindrical inner wall 12, the cylindrical outer wall 13 and the top wall 11 is formed into a hollow structure. Figure 1 As shown, it is used to accommodate an annular valve body 3 in a hollow structure.

[0063] Multiple vent holes 14 are provided at the intersection of the cylindrical outer wall 13 and the bottom surface of the upper cover 1. In this embodiment, six quadrilateral vent holes 14 are evenly spaced around the entire circumference of the lower portion of the cylindrical outer wall 13. Each vent hole 14 is half located at the lower portion of the cylindrical outer wall 13, with the other half extending to the bottom surface of the upper cover 1, allowing gas to escape as quickly as possible.

[0064] Furthermore, vent holes 15 are also formed in the lower portion of the cylindrical inner wall 12. Four vent holes 15 are evenly spaced along the entire circumference of the lower portion of the cylindrical inner wall 12, but six vent holes may also be provided. To ensure the strength of the cylindrical inner wall 12, the vent holes 15 are preferably provided only in the lower portion of the cylindrical inner wall 12 and do not extend to the bottom surface of the upper cover 1.

[0065] On the edge portion 17 of the bottom surface of the upper cover 1, four circular welding recesses 16 are provided at equal intervals. These recesses are used to locate welding points when the upper cover 1 and the lower cover 2 are spot welded together.

[0066] like Figure 4A and Figure 4B As shown, the lower cover 2 is formed into a flat cover bottom shape by a cover bottom 21 and a bent portion 22 formed around the cover bottom 21. Eight valve holes 23 are formed at equal intervals on a circular ring with a radius of R around the center of the circle of the cover bottom 21. Here, R = (r1 + r2) / 2.

[0067] like Figure 1 As shown, the bent portion 22 is formed by forging or other means on the outer peripheral edge of the lower cover 2, extending in a direction closer to the plane of the upper cover 1 relative to the plane of the cover bottom 21 of the lower cover 2. The upper cover 1 is positioned on the cover bottom 21 of the lower cover 2 surrounded by the bent portion 22, and the upper and lower covers 1 and 2 are welded together by spot welding at the recessed portion 16 on the edge of the upper cover 1.

[0068] Figure 5A 、 Figure 5B 1 is a diagram for explaining the valve body 3. The valve body 3 is formed into a circular ring shape and can be placed in the annular hollow structure of the upper cover 1 consisting of the cylindrical inner wall 12, the cylindrical outer wall 13 and the top wall 11. Figure 1 As shown, the bottom surface of the valve body 3 abuts the upper surface of the cover bottom 21 of the lower cover 2, sealing the eight valve holes 23 formed in the lower cover 2. The top surface of the valve body 3 abuts the lower surface of the top wall 11 of the upper cover 1. This top wall 11 of the upper cover 1 applies downward pressure to the valve body 3, preventing it from shifting left or right within the hollow structure. Furthermore, the inner and outer ring surfaces of the valve body 3 do not contact the cylindrical inner and outer walls 12, 13. Instead, a gap is left between the inner and outer walls 12, 13 to facilitate gas discharge.

[0069] Below, refer to Figure 1 and Figure 6 The improvements and beneficial technical effects of the present invention compared with the prior art are described.

[0070] like Figure 6 As shown, the upper cover in the prior art has a cylindrical convex portion 6 formed upward in the center. The convex portion 6 is formed into a hollow structure and accommodates a valve body 7. The valve body 7 can be formed in a square, cylindrical or other shape and is used to close a single valve hole 8 formed in the center of the lower cover.

[0071] At the lower part of the side wall of the cylindrical convex portion 6 of the upper cover, there is formed a vent hole 50 extending all the way to the bottom of the upper cover. Although not shown in the figure, generally speaking, there are usually more than 4 vent holes 50 formed around the lower part of the cylindrical convex portion.

[0072] However, if the battery is dropped and the convex portion 6 is deformed, the valve body 7 housed therein becomes more susceptible to deformation under pressure, i.e., its compression rate. This can lead to the generation of large amounts of gas inside the battery. Even if the operating pressure of the gas generated within the battery exceeds a predetermined threshold, this gas pressure may not be able to cause the valve body, which has increased in compression rate, to contract, preventing the gas from being smoothly discharged through the vent hole 8 in the center of the lower cover 53. In this situation, the battery is prone to explosion, posing a serious safety risk.

[0073] In contrast, firstly, the present invention forms an annular convex portion 10 on the upper cover 1 instead of a cylindrical convex portion. The annular convex portion 10 is composed of a cylindrical inner wall 12, a cylindrical outer wall 13 and a top wall 11. Figure 6 Compared with the cylindrical convex portion 6 of the upper cover 1 of the prior art, the annular convex portion 10 of the present invention has a stronger anti-deformation ability.

[0074] Secondly, the present invention does not form a single valve hole in the lower cover 2. Instead, it forms eight valve holes 23 arranged in a ring around the center of the lower cover 2. The area of ​​each of the eight valve holes 23 is roughly the same as that of a single valve hole in the prior art. Compared to the single vent hole formed in the center of the lower cover in the prior art, even if the annular convex portion of the upper cover 1 locally deforms and the local compression rate of the valve body increases, gas can still be discharged preferentially through the vent hole on the side of the valve body where the compression rate remains unchanged, thereby reliably improving battery safety.

[0075] In addition, the present invention forms vent holes 15 and 14 on the lower part of the cylindrical inner wall 12 and the cylindrical outer wall 13 of the annular convex part of the upper cover 1, respectively. Compared with the prior art method of forming vent holes only on the lower part of the outer wall of the cylindrical convex part, the number of vent holes formed on the inner and outer walls of the annular convex part 10 in the present invention is larger, and the total area is larger, so that the gas can be discharged more smoothly. In addition, the vent holes are also formed on the cylindrical inner wall 12 because the direction of the gas is uncertain when the valve body is lifted and discharged outward. If the gas is discharged to the inside of the valve body, that is, the cylindrical inner wall, and there is no vent hole on the cylindrical inner wall, an instantaneous gas accumulation will be formed, causing the sealing plate to fly off the battery. During the assembly process of the sealing plate, there will be some deviation in the positioning of the valve body, which may cause this phenomenon.

[0076] In addition, the number of the air release holes formed in the cylindrical inner wall 12 and the number of the air release holes formed in the cylindrical outer wall 13 are 6 and 4, respectively, in the present embodiment, but other numbers may be formed.

[0077] The number of valve holes 23 formed on the bottom 21 of the lower cover 2 is 8, but it can also be formed in other numbers, but it is preferred to form at least 2 or more along the radius R, and the total area is roughly the same as or larger than the area of ​​a single vent hole on the lower cover in the prior art.

[0078] The valve body can be made of the same rubber material as in existing technologies, or other materials, without specific limitations. Because the valve body deforms vertically under air pressure, the air pressure pushes the valve body open from below and then vents from both sides. Regardless of the valve body's shape, as long as the ratio of vertical deformation of the valve body under pressure within the sealing plate is consistent and the residual space within the sealing plate (excluding the valve body's volume) is consistent, the actuating pressure will be largely consistent regardless of the material.

[0079] The present invention is not limited to the specific embodiments described in this specification, and various modifications are possible without departing from the spirit of the present invention.

Claims

1. A sealing plate for a battery, comprising an upper cover, a lower cover and a valve body, characterized in that: The upper cover has an annular convex portion and an edge portion formed around the convex portion, wherein the annular convex portion is formed into a hollow convex shape by a cylindrical inner wall with different diameters, a cylindrical outer wall, and a top wall connecting the top ends of the two side walls, and a plurality of air release holes are formed on the convex portion; The lower cover has a cover bottom, the edge portion of the upper cover is combined with the cover bottom of the lower cover by spot welding, and the lower cover has a plurality of valve holes, which are arranged in a ring shape corresponding to the annular convex portion. A valve body covering the plurality of valve holes is provided in a space formed by the hollow convex portion and the cover bottom of the lower cover. The cylindrical inner wall and the cylindrical outer wall stand upright from the bottom surface of the bottom cover of the upper cover, The lower cover also has a bent portion formed around the bottom of the cover, and the bent portion extends in a direction closer to the plane of the upper cover relative to the plane of the cover bottom of the lower cover. The upper cover is positioned on the bottom cover of the lower cover circled by the bent portion, and the upper cover and the lower cover are welded together by spot welding at the concave portion of the edge of the upper cover.

2. The battery sealing plate according to claim 1, wherein The valve body is formed in a ring shape.

3. The battery sealing plate according to claim 1, wherein The plurality of air release holes are respectively provided on the cylindrical inner wall and the cylindrical outer wall.

4. The battery sealing plate according to claim 3, wherein A plurality of the vent holes are formed at equal intervals around the cylindrical outer wall and the cylindrical inner wall on the lower portion of each of the cylindrical outer wall and the cylindrical inner wall, wherein the vent holes formed on the lower portion of the cylindrical outer wall extend to the edge portion of the upper cover.

5. The battery sealing plate according to claim 3, wherein The lower cover is formed with 8 valve holes. Six vent holes are formed on the outer cylindrical wall. Four air release holes are formed on the cylindrical inner wall.

6. The battery sealing plate according to claim 1, wherein The radius of the ring formed by the plurality of valve holes is half of the sum of the radii of the cylindrical outer wall and the cylindrical inner wall. 7 . A battery comprising: a case having an opening; an electrode plate assembly including a positive electrode plate and a negative electrode plate inserted into the case; and the battery sealing plate according to claim 1 .

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