Battery safety valve and battery

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a battery safety valve and a power battery, the battery safety valve comprises a shell cover, a spring and a top cover plate are sequentially arranged in the shell cover, the top cover plate is provided with a liquid injection hole, and the liquid injection hole is welded and sealed after liquid injection. According to the utility model, the liquid injection hole and the safety valve are integrated, so that the problem of failure of the anti-explosion valve during liquid injection can be solved, and electrolyte can be prevented from leaking from the safety valve in the whole liquid injection process.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium-ion batteries, and in particular relates to a battery safety valve and a battery. Background Art

[0002] Currently, battery covers are equipped with two essential structures: a liquid injection hole and an explosion-proof valve. The explosion-proof valve is generally welded to the cover in advance by the cover manufacturer, while the liquid injection hole is welded and sealed after liquid injection. The presence of the explosion-proof valve limits the injection pressure. If the pressure is too high, the explosion-proof valve will be damaged prematurely, and the battery cell will fail. In addition, when the battery is in operation, a certain amount of gas will inevitably be released during the entire redox process. As the number of cycles accumulates, the gas will also increase. If these gases cannot be released in time, it will lead to an increase in the internal resistance of the battery and lithium precipitation, which will further reduce the battery's charge and discharge efficiency. If the battery gas pressure is too high, it will break through the explosion-proof valve, causing the battery to leak or even explode.

[0003] To this end, a Chinese patent discloses an explosion-proof valve with an injection hole (publication number: CN 218919198 U). In the explosion-proof valve with an injection hole, the explosion-proof valve groove is recessed in the substrate, and the explosion-proof valve groove has an explosion-proof valve plane; the injection hole is provided on the explosion-proof valve plane and passes through the substrate; the exhaust hole is provided on the explosion-proof valve plane and is located on one side of the injection hole; the explosion-proof sealing sheet covers the explosion-proof valve plane and is fixed to the explosion-proof valve groove; the explosion-proof valve protection sheet is attached to the substrate and covers the explosion-proof valve groove. This patent directly welds the explosion-proof valve outside the injection hole and the exhaust hole. The Chinese patent also discloses a spring-loaded battery safety valve (publication number: CN 215527885 U), which includes a main valve body, a vent channel, a spring exhaust assembly, and a leakage reflux assembly. The vent channel is provided through the center of the main valve body, the spring exhaust assembly is connected to the vent channel, the leakage reflux assembly is provided through the main valve body and surrounds the spring exhaust assembly, the spring exhaust assembly includes a vent cover, a vent hole, a connecting ring, a compression spring, and a cone valve, and the leakage reflux assembly includes a drainage hole, a liquid storage tank, an annular valve, a retaining ring, a valve stem, and a pressure spring. The patent can automatically vent the battery when the internal pressure is too high. The above two technical routes will cause excessive injection pressure during battery filling, resulting in failure of the explosion-proof valve. In addition, during the later cycle of the battery, the SEI film will continue to repair and generate, and an indefinite amount of gas will be generated at this time. The presence of gas will reduce the performance of the battery and reduce the charge and discharge efficiency. Excessive gas pressure will also break through the explosion-proof valve, causing the battery cell to fail and bring immeasurable dangers. Therefore, both structures cannot solve the high pressure problem caused by liquid injection and the problem of timely pressure relief of gas accumulation, and the design structure is too complicated to be used in reality. Utility Model Content

[0004] The purpose of the utility model is to provide a battery safety valve and a battery to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] On the one hand, the present invention provides a battery safety valve, including a shell cover, wherein the shell cover is provided with a through hole, a spring and a top cover plate are provided in the through hole, the two ends of the spring are respectively fixed to the shell cover and the top cover plate, and the top cover plate is provided with a liquid injection hole, which is sealed after the liquid is injected.

[0007] Preferably, the through hole comprises a liquid inlet and air outlet cavity, a spring cavity and a cover cavity which are connected in sequence, wherein the diameter of the cover cavity is larger than the diameter of the spring cavity, and the diameter of the spring cavity is larger than the diameter of the liquid inlet and air outlet cavity.

[0008] Preferably, the top of the spring is fastened to the top cover plate by welding or bonding, and the bottom of the spring is fixed to the bottom of the spring cavity by bonding or clamping.

[0009] Preferably, a liquid leakage hole is provided on the side of the liquid inlet and air outlet cavity.

[0010] Preferably, there are at least two leakage holes.

[0011] Preferably, the periphery and bottom of the cover cavity are both provided with soft pads.

[0012] Preferably, the soft pad is a silicone rubber pad or a neoprene rubber pad.

[0013] Preferably, a spacer is provided at the bottom of the top cover plate, a spacer is provided inside the spacer, and the spring is installed in the spacer.

[0014] Preferably, the diameter of the top of the injection hole is larger than the diameter of the bottom.

[0015] On the other hand, the present invention further provides a battery, comprising the battery safety valve as described above, wherein a positive electrode column and a negative electrode column are respectively installed on both sides of the shell cover.

[0016] The beneficial effects of the present invention are as follows: by integrating the injection port with the safety valve, the present invention can solve the problem of explosion-proof valve failure during injection and prevent electrolyte leakage from the safety valve during the entire injection process. During the subsequent battery cycle, the presence of the safety valve can promptly discharge gas generated inside the battery, which is more conducive to the performance of the battery, reduces the risk of battery failure, and protects human safety to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional diagram of the safety valve in the present utility model;

[0018] Figure 2 This is an exploded view of the utility model;

[0019] Figure 3 This is a schematic diagram of the safety valve in the present invention in a non-working state;

[0020] Figure 4 This is a working diagram of the safety valve in the utility model;

[0021] Figure 5 This is a schematic structural diagram of another safety valve of the present utility model;

[0022] Explanation of the accompanying symbols: 1. Shell cover; 2. Spring; 3. Top cover plate; 4. Liquid injection hole; 5. Liquid inlet and air outlet cavity; 6. Spring cavity; 7. Cover plate cavity; 8. Liquid leakage hole; 9. Positive pole; 10. Negative pole; 11. Cushion; 12. Spacer. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "fixedly connected," and "fixed connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0026] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings and preferred embodiments.

[0027] like Figure 1 and Figure 2 As shown, a battery safety valve comprises a shell cover 1, in which a spring 2 and a top cover plate 3 are sequentially installed. The top cover plate has an injection hole 4, which is welded and sealed after the injection hole is filled. Because excessive injection pressure may occur during battery injection, causing the explosion-proof valve to fail and liquid to overflow from the safety valve, this device integrates the battery's injection hole and safety valve into a single unit. During injection, liquid is injected from the injection hole, and the safety valve remains stationary, preventing electrolyte from overflowing from the safety valve. This device can solve the problem of electrolyte overflow caused by injection pressure during injection, and also solve the problem of continuous gas generation during subsequent battery cycles, greatly ensuring the electrical performance of the battery cell and the safety of personnel.

[0028] Specifically, the shell cover is provided with a liquid inlet and air outlet cavity 5, a spring cavity 6 and a cover plate cavity 7 which are connected in sequence, wherein the diameter of the cover plate cavity is larger than the diameter of the spring cavity and the diameter of the liquid inlet and air outlet cavity. The spring is installed in the spring cavity 6, and the top cover plate 3 is installed in the cover plate cavity, and the top of the spring is fastened to the top cover plate. The bottom of the spring is fixed to the spring cavity. The top and bottom of the spring can be welded or bonded to the top cover plate and the spring cavity in multiple places, or the spring can be buried in the top cover plate and the spring cavity and integrated with them. This structure is to extend the service life of the spring, but any structure can achieve the purpose of pressure relief.

[0029] The spring constants used in this application vary depending on the properties of the springs used. Depending on the pressure required to open the top cover, you can adjust the spring constants based on actual needs. The spring constants required to open the top cover vary depending on the battery model.

[0030] Springs with different spring coefficients only determine the number of times the gas is released. The presence of the surrounding soft pads is mainly to ensure the sealing effect. The friction generated by it will definitely be less than the elastic force generated by the spring due to the accumulation of gas. In order to seal the top cover plate and the cover plate cavity, soft pads 11 are attached to the periphery and bottom of the cover plate cavity. The soft pads can be made of polymer synthetic materials such as silicone rubber and chloroprene rubber. The soft pads have the characteristics of high elasticity, low compression permanent deformation and good cyclic loading performance. The presence of the soft pads can make it have a closer fit with the top cover plate, thereby isolating the influence of the external environment on the battery. Since the upper part of the liquid inlet and air outlet cavity is provided with a step, the step can support the bottom of the spring. In the initial state, the spring as a whole has no deformation and can be directly placed in the spring cavity 6 for fixing. Therefore, the presence of the liquid inlet and air outlet cavity can ensure that the spring has no deformation.

[0031] Furthermore, a leakage hole 8 is provided on the side of the liquid inlet and gas outlet cavity 5. The upper portion of the leakage hole 8 communicates with the bottom of the spring cavity, and the lower portion of the leakage hole extends all the way to the lower portion of the housing cover and communicates with the interior of the battery. There are at least two leakage holes. During the exhaust and pressure relief process, a small amount of electrolyte fluid inevitably enters the spring cavity. The presence of the leakage hole prevents the electrolyte fluid from lingering in the spring cavity.

[0032] Further, if Figure 5 As shown, the utility model also discloses another embodiment of a safety valve. Specifically, a spacer 12 for mounting a spring is provided at the lower part of the top cover plate. The spacer has a partition layer inside, and the spring is mounted in the partition layer. Since the spring may be corroded if it directly contacts the electrolyte during injection, thereby reducing the service life of the safety valve, the spring is protected by the spacer, which can avoid contact between the electrolyte and the spring during injection, thereby effectively improving the service life of the spring.

[0033] Furthermore, the radius of the top of the liquid injection hole is greater than the radius of the bottom of the liquid injection hole.

[0034] The utility model also discloses a battery, comprising the battery safety valve. A positive electrode column 9 and a negative electrode column 10 are respectively installed on both sides of the shell cover.

[0035] The battery can be applied to power batteries, energy storage batteries or consumer batteries without specific limitations.

[0036] The battery's filling, sealing and:

[0037] First, the electrolyte is injected through the injection hole 4 on the top of the top cover plate 3. The radius of the top of the injection hole is larger than the radius of the bottom of the injection hole. The liquid pressure generated by the injection will exert a downward force on the entire safety valve due to the relative relationship between the radii, thus preventing liquid from overflowing from the safety valve during high-pressure injection. After the battery completes the first injection, formation, and second injection, the battery injection hole is sealed.

[0038] After the battery completes the welding of the liquid injection hole, the battery will reach a relatively stable stage, and the gas will not increase suddenly. Only a small amount of gas will be generated as the battery is charged and discharged. At this time, this part of the gas will enter the spring cavity 6 where the spring is located through the liquid inlet and outlet cavity 5 and the leakage hole 8. In addition, the existence of the liquid inlet and outlet cavity 5 can ensure the support of the spring, so the spring can maintain its original length in the initial state. The gas will continue to accumulate with the cycle of charging and discharging. As the gas accumulates, the pressure rises, the spring 2 is connected to the top cover plate, and the top cover plate will be pushed by the gas. At this time, the spring will produce elastic deformation. When the deformation of the spring is greater than the thickness of the top cover plate, the gas can be discharged (such as Figure 4As batteries cycle, sometimes reaching tens of thousands of cycles, and gas accumulates, a small amount of fluid inevitably enters the spring cavity during degassing and pressure relief. The presence of the leak hole prevents fluid from lingering in the spring cavity. When the battery ages or fails, gas production increases dramatically. Spring 2 deforms promptly to release internal pressure, preventing battery failure and potential safety incidents.

[0039] For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A battery safety valve, characterized in that: The utility model comprises a shell cover, wherein the shell cover is provided with a through hole, a spring and a top cover plate are arranged in the through hole, two ends of the spring are respectively fixed to the shell cover and the top cover plate, and the top cover plate is provided with a liquid injection hole, which is sealed after the liquid is injected.

2. The battery safety valve according to claim 1, characterized in that: The through hole comprises a liquid inlet and air outlet cavity, a spring cavity and a cover cavity which are connected in sequence, wherein the diameter of the cover cavity is larger than the diameter of the spring cavity, and the diameter of the spring cavity is larger than the diameter of the liquid inlet and air outlet cavity.

3. The battery safety valve according to claim 2, characterized in that: The top of the spring is fastened to the top cover plate by welding or bonding, and the bottom of the spring is fixed to the bottom of the spring cavity by bonding or clamping.

4. The battery safety valve according to claim 2, characterized in that: A liquid leakage hole is provided on the side of the liquid inlet and air outlet cavity.

5. The battery safety valve according to claim 4, characterized in that: There are at least two leakage holes.

6. The battery safety valve according to claim 2, characterized in that: The periphery and bottom of the cover plate cavity are both covered with soft pads.

7. The battery safety valve according to claim 6, characterized in that: The soft pad is a silicone rubber pad or a neoprene pad.

8. The battery safety valve according to claim 1, characterized in that: A spacer is provided at the bottom of the top cover plate, a spacer is provided in the spacer, and a spring is arranged in the spacer.

9. The battery safety valve according to claim 1, characterized in that: The diameter of the top of the injection hole is larger than the diameter of the bottom.

10. A battery, characterized in that: The battery safety valve comprises the battery safety valve according to any one of claims 1 to 9, wherein a positive electrode column and a negative electrode column are respectively installed on both sides of the shell cover.

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