End cover assembly of battery and battery

Abstract

The end cover assembly of the battery comprises an end cover, a pressure relief hole is formed in the end cover, the end cover comprises a main body part and a thinning area, the thinning area surrounds the pressure relief hole, the main body part is arranged on the side, away from the pressure relief hole, of the thinning area, and the thickness of the thinning area is smaller than that of the main body part; and the waterproof breathable film is connected to the thinning area, covers the pressure relief hole and is used for enabling gas to penetrate through the waterproof breathable film, and the bursting pressure of the waterproof breathable film is smaller than that of the end cover. On one hand, gas released in the battery circulation process can be smoothly discharged through the waterproof gas-permeable membrane so as to balance the internal and external air pressures of the battery. And on the other hand, when the battery is subjected to thermal runaway and the like, the waterproof gas-permeable membrane can be broken to quickly discharge gas in the battery, and compared with a traditional aluminum sheet explosion-proof valve, the waterproof gas-permeable membrane is lower in risk of hurting people or external equipment when being broken and sprayed out, and is safer to use.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an end cover assembly of a battery and a battery. Background Art

[0002] In order to ensure the safety of the battery, existing batteries are usually equipped with explosion-proof valves on the end caps. When the battery encounters severe situations such as thermal runaway and short circuit, the explosion-proof valve will open due to excessive internal air pressure to quickly discharge a large amount of gas, thereby preventing the battery from exploding.

[0003] Existing explosion-proof valves are usually made of aluminum sheets, but this design cannot effectively release the gas generated by the battery during the cycle process. In addition, when the explosion-proof valve is opened due to an emergency situation such as thermal runaway of the battery, the aluminum sheet will break and spray out, which may cause harm to personnel or damage to surrounding equipment. Utility Model Content

[0004] In view of the above existing situation, the present invention provides a battery end cover assembly and a battery to discharge the gas inside the battery during the battery cycle and reduce the risk of harm to people or external equipment when the battery valve is opened.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the utility model provides an end cover assembly of a battery, which includes: an end cover, the end cover is provided with a pressure relief hole, the end cover includes a main body and a thinning area, the thinning area surrounds the pressure relief hole, the main body is arranged on the side of the thinning area away from the pressure relief hole, the thickness of the thinning area is less than the thickness of the main body; a waterproof breathable membrane, connected to the thinning area, the waterproof breathable membrane covers the pressure relief hole, and is used to allow gas to pass through the waterproof breathable membrane, and the bursting pressure of the waterproof breathable membrane is less than the bursting pressure of the end cover.

[0006] In the end cover assembly of the battery involved in the utility model, optionally, the end cover is used to cover the battery cell of the battery; the main body includes a first side facing away from the battery cell, the thinning area includes a second side facing away from the battery cell, and the waterproof breathable membrane includes a third side facing away from the battery cell; the second side and the third side are located on the side of the plane where the first side is located facing the battery cell.

[0007] In the end cover assembly of the battery involved in the utility model, optionally, the second side surface and the third side surface are on the same plane; or, the second side surface is located between the first side surface and the third side surface.

[0008] In the end cover assembly of the battery involved in the utility model, optionally, the pressure resistance value of the thinned area is greater than the pressure resistance value of the waterproof breathable membrane.

[0009] In the end cap assembly of the battery involved in the utility model, optionally, the pressure resistance value of the thinning area is a1, and the value range of a1 is: 0.9 MPa ≤ d1 ≤ 2 MPa; the pressure resistance value of the waterproof and breathable membrane is a2, and the value range of a2 is: 0.7 MPa ≤ a2 < 0.9 MPa.

[0010] In the end cap assembly of the battery involved in the utility model, optionally, the thickness of the thinning area is greater than or equal to the thickness of the waterproof and breathable membrane.

[0011] In the end cap assembly of the battery involved in the utility model, optionally, the ratio of the thickness of the thinning area to the thickness of the end cap is between 50% and 80%.

[0012] In the end cap assembly of the battery involved in the utility model, optionally, the thickness of the waterproof and breathable membrane is between 0.1 mm and 0.5 mm.

[0013] In the end cap assembly of the battery involved in the utility model, optionally, the thinning area and the waterproof and breathable membrane are in interference fit.

[0014] The second aspect of the present utility model provides a battery, which includes the end cap assembly of the battery as described above.

[0015] The end cap assembly of the battery involved in the present utility model includes an end cap and a waterproof and breathable membrane. Among them, the end cap is provided with a pressure relief hole, and the waterproof and breathable membrane is used to cover the pressure relief hole. On the one hand, the gas released during the battery cycle can be smoothly discharged through the waterproof and breathable membrane to balance the internal and external pressures of the battery, thereby avoiding excessive internal pressure of the battery and affecting the safety performance of the battery. On the other hand, when the battery undergoes thermal runaway or other situations, resulting in the internal pressure of the battery reaching a preset value, since the bursting pressure of the waterproof and breathable membrane is less than the bursting pressure of the end cap, the waterproof and breathable membrane will rupture to form a pressure relief channel communicating with the pressure relief hole, thereby quickly discharging the gas inside the battery and preventing the battery from exploding and other dangers. And compared with the traditional aluminum sheet explosion-proof valve, the risk of the waterproof and breathable membrane causing harm to people or external equipment when rupturing and spraying is lower, and it is safer to use. In addition, the setting of the thinning area can also deform when the internal pressure of the battery is too high, and then exert a certain extrusion on the waterproof and breathable membrane, promoting the rupture of the waterproof and breathable membrane to release pressure, further improving the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] To more fully understand the present application and its beneficial effects, the following description will be made in conjunction with the accompanying drawings, where the same reference numerals in the following description represent the same parts.

[0018] Figure 1 It is a schematic diagram showing the overall structure of the end cap assembly of the battery involved in the present application.

[0019] Figure 2 It shows what is involved in the present application Figure 1 An enlarged schematic view of part A.

[0020] Figure 3 It is an exploded view of the end cap assembly of the battery involved in the present application.

[0021] Figure 4 It is a partial cross-sectional view of the end cap assembly of the battery involved in the present application.

[0022] Figure 5 It shows what is involved in the present application Figure 4 An enlarged schematic view of part B.

[0023] Figure 6 It is a top view of the battery involved in the present application.

[0024] Figure 7 It is a side view of the battery involved in the present application.

[0025] Reference numerals: 1, end cap; 11, pressure relief hole; 12, main body part; 13, thinning area; 14, accommodation space; 2, waterproof and breathable membrane. Detailed implementation manners

[0026] Hereinafter, with reference to the accompanying drawings, the preferred implementation manners of the present utility model will be described in detail. In the following description, the same symbols are given to the same components, and repeated descriptions are omitted. In addition, the drawings are only schematic diagrams, and the proportional relationship of the dimensions between components or the shape of components, etc. may be different from the actual ones. It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0027] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0028] To ensure the safety of the battery, existing batteries usually have an explosion-proof valve installed on the end cap. When the battery undergoes thermal runaway, short circuit, or other adverse conditions, the explosion-proof valve will open due to excessive internal pressure in the battery to quickly discharge a large amount of gas, thereby preventing the battery from exploding. Existing explosion-proof valves are usually made of aluminum sheets, but this design cannot effectively release the gas generated during the battery's cycling process. Moreover, when the battery experiences an emergency such as thermal runaway and causes the explosion-proof valve to open, the aluminum sheet will rupture and spray out, which may cause harm to personnel or damage to surrounding equipment.

[0029] For this reason, referring to Figures 1 to 4 , a first aspect of the present application provides an end cap assembly for a battery, which includes an end cap 1 and a waterproof and breathable membrane 2. The end cap 1 is provided with a pressure relief hole 11. The end cap 1 includes a main body portion 12 and a thinning area 13. The thinning area 13 surrounds the pressure relief hole 11. The main body portion 12 is disposed on the side of the thinning area 13 away from the pressure relief hole 11. The thickness of the thinning area 13 is less than the thickness of the main body portion 12; the waterproof and breathable membrane 2 is connected to the thinning area 13. The waterproof and breathable membrane 2 covers the pressure relief hole 11 and is used to allow gas to pass through the waterproof and breathable membrane 2. The bursting pressure of the waterproof and breathable membrane 2 is less than the bursting pressure of the end cap 1.

[0030] It can be understood that in the related art, the end cap 1 is usually a part of the battery housing. The battery cell is placed inside the housing, and the housing plays a role in protecting and supporting the battery cell. In some examples, the end cap 1 can be integrally formed with the battery housing. In other examples, the end cap 1 can also be separately provided from the battery housing.

[0031] The end cap assembly for the battery involved in the present application includes an end cap 1 and a waterproof and breathable membrane 2. Among them, the end cap 1 is provided with a pressure relief hole 11, and the waterproof and breathable membrane 2 is used to cover the pressure relief hole 11. On the one hand, the gas released during the battery's cycling process can be smoothly discharged through the waterproof and breathable membrane 2 to balance the internal and external pressures of the battery, thereby avoiding excessive internal pressure of the battery and affecting the safety performance of the battery. On the other hand, when the battery undergoes thermal runaway or other conditions, resulting in the internal pressure of the battery reaching a preset value, since the bursting pressure of the waterproof and breathable membrane 2 is less than the bursting pressure of the end cap 1, the waterproof and breathable membrane 2 will rupture to form a pressure relief channel communicating with the pressure relief hole 11, thereby quickly discharging the gas inside the battery and preventing the battery from exploding and other dangers. Moreover, compared with the traditional aluminum sheet explosion-proof valve, the risk of the waterproof and breathable membrane 2 causing harm to people or external equipment when rupturing and spraying out is lower, and it is safer to use. In addition, the setting of the thinning area 13 can also deform when the internal pressure of the battery is too high, and then exert a certain extrusion on the waterproof and breathable membrane 2, promoting the rupture of the waterproof and breathable membrane 2 to release pressure, further improving the safety performance of the battery.

[0032] Specifically, a battery cycle refers to the charge-discharge cycle of electrical energy during the use of a battery. Each complete charge-discharge process, that is, the change of the battery from a fully discharged state to a fully charged state, is called a battery cycle. During the battery cycle, due to side reactions of the cell materials, decomposition of the electrolyte, etc., gas may be released, which will cause gas to be generated inside the cell. For example, in lead-acid batteries and lithium-ion batteries, gas generation may occur during both the charging and discharging processes. In lithium-ion batteries, gas release is usually related to the thermal runaway phenomenon of the battery. When the battery is overcharged or over-discharged, or a short circuit occurs inside the battery, it may cause the internal temperature of the battery to rise, triggering thermal runaway. During thermal runaway, the chemical substances inside the battery may decompose, releasing gases such as carbon dioxide, water vapor, and possibly toxic gases such as hydrogen and methane. The release of these gases may cause the battery to expand, be damaged, or even catch fire. Therefore, the end cap assembly of the battery involved in the present application can solve the problem of gas discharge during battery cycling or thermal runaway, thereby better improving the safety performance of the battery.

[0033] Referring to Figure 4 , as an embodiment, the end cap 1 is used to cover the cell of the battery; the main body portion 12 includes a first side facing away from the cell, the thinning region 13 includes a second side facing away from the cell, and the waterproof and breathable membrane 2 includes a third side facing away from the cell; the second side and the third side are located on the side of the plane where the first side is located facing the cell. It can be understood that, taking the plane where the first side is located as the reference plane, both the thinning region 13 and the waterproof and breathable membrane 2 are recessed in the direction of the accommodation space 14 and will not protrude from the plane where the first side is located. Thus, the overall structure of the battery end cap assembly is more compact, which can reduce the space occupied by the battery end cap assembly and improve the space utilization rate. In addition, from a safety perspective, if the thinning region 13 or the waterproof and breathable membrane 2 protrudes from the plane where the first side is located, when the battery is impacted or dropped from the outside, it is very easy to cause damage to the thinning region 13 and the waterproof and breathable membrane 2, and even cause the waterproof and breathable membrane 2 to open incorrectly, affecting the safety performance of the battery.

[0034] As an embodiment, the second side and the third side are on the same plane. Thus, the overall outer wall of the battery can be made smoother and the structure can be more concise. In addition, as another embodiment, the second side is located between the first side and the third side. It can be understood that in this embodiment, the first side, the second side, and the third side are recessed step by step in the direction facing the accommodation space 14.

[0035] As an embodiment, the pressure resistance value of the thinning area 13 is greater than that of the waterproof and breathable membrane 2. It should be noted that the pressure resistance value defined in this application refers to the ratio of the pressure received per unit area, which describes the tolerance ability of an object or structure under the action of pressure. The higher the pressure resistance value, the higher the pressure it can withstand and the better the pressure-bearing performance. With this setting, the pressure resistance value of the waterproof and breathable membrane 2 is smaller, which can ensure that when the internal pressure of the battery rises abnormally, the waterproof and breathable membrane 2 can rupture first, thereby guiding the pressure release and avoiding the rupture of the thinning area 13.

[0036] As an embodiment, the pressure resistance value of the thinning area 13 is a1, and the value range of a1 is: 0.9 MPa ≤ d1 ≤ 2 MPa; the pressure resistance value of the waterproof and breathable membrane 2 is a2, and the value range of a2 is: 0.7 MPa ≤ a2 < 0.9 MPa. Thus, it can be ensured that the pressure resistance value of the waterproof and breathable membrane 2 is less than that of the thinning area 13, and when the internal pressure of the battery rises abnormally, the waterproof and breathable membrane 2 can rupture first. Specifically, in some examples, the pressure resistance value a1 of the thinning area 13 can be set to one of 0.9 MPa, 1.2 MPa, 1.5 MPa, 1.8 MPa, 2 MPa; in some examples, the pressure resistance value a2 of the waterproof and breathable membrane 2 can be set to one of 0.7 MPa, 0.75 MPa, 0.8 MPa, 0.85 MPa.

[0037] As an embodiment, the thickness of the thinning area 13 is greater than or equal to the thickness of the waterproof and breathable membrane 2. Thus, when the internal pressure of the battery rises abnormally, it can be ensured that the thinning area 13 will not rupture earlier than the waterproof and breathable membrane 2, without affecting the rapid rupture and pressure relief of the waterproof and breathable membrane 2.

[0038] As an embodiment, the ratio of the thickness of the thinning area 13 to the thickness of the end cap 1 is between 50% and 80%. Thus, the thickness of the thinning area 13 is thinner than that of the end cap 1. It can be understood that the main function of the end cap 1 is to protect the battery, maintain the mechanical strength and stability of the battery to better withstand external impacts, and the end cap 1 is also used to prevent external dust, moisture, etc. from affecting the inside of the battery. Therefore, in this embodiment, the thickness of the end cap 1 is thicker. And the thinning area 13 is set to be thinner than the end cap 1. On the one hand, during the cycling of the battery, thermal expansion and contraction will occur. The thinner thinning area 13 can make it easier to deform under pressure, so as to reduce the influence on the end cap 1 caused by thermal expansion and prevent the end cap 1 from rupturing due to excessive internal pressure of the battery. On the other hand, the thinner thinning area 13 can also ensure that it does not protrude from the first side of the end cap 1.

[0039] As an embodiment, the thickness of the waterproof and breathable membrane 2 is between 0.1 mm and 0.5 mm. Specifically, in some examples, the thickness of the waterproof and breathable membrane 2 can be set to 0.1 mm, 0.3 mm or 0.5 mm.

[0040] Reference Figure 4 and Figure 5 As an embodiment, the thinning area 13 is in interference fit with the waterproof and breathable membrane 2. Specifically, when assembling the waterproof and breathable membrane 2, the waterproof and breathable membrane 2 can be pressed into the connection part of the thinning area 13 by the pressing method.

[0041] In some examples, the waterproof and breathable membrane 2 can be made of polytetrafluoroethylene. Among them, the waterproof and breathable membrane 2 made of polytetrafluoroethylene can prevent the passage of water molecules but allow the passage of gas. Specifically, the pore structure of the waterproof and breathable membrane 2 can be set according to actual needs, such as setting the size and distribution of the pores of the waterproof and breathable membrane 2 as needed to meet the required air permeability and waterproof performance requirements.

[0042] In some examples, the waterproof and breathable membrane 2 can be set as a unidirectional waterproof and breathable membrane, which only allows the gas inside the battery to be discharged outward.

[0043] In some examples, the waterproof and breathable membrane 2 can be in an elliptical or circular shape, etc., and an annular fixing member can be fixedly wrapped around its edge, so as to facilitate the interference fit between the waterproof and breathable membrane 2 and the thinning area 13.

[0044] The second aspect of the present application provides an end cover assembly of a battery, which includes the end cover assembly of the battery as above.

[0045] Reference Figure 6 and Figure 7 As an embodiment, the battery has a cuboid structure, half of the length of the battery is h1, the height of the battery is h2, and the ratio of h1 to h2 is 40% - 60%.

[0046] Such as Figure 7 , in this embodiment, the waterproof and breathable membrane 2 is arranged in the central area at the top of the battery, and the ratio of h1 to h2 is 40% - 60%. In this way, it can avoid the end cover of the battery from exploding when the battery is in thermal runaway.

[0047] In some examples, the ratio of h1 to h2 can be 40%, 50% or 60%.

[0048] It should be noted that the ratio of h1 to h2 is set based on the aspect ratio of the battery design. In battery design, the aspect ratio of the battery has an important impact on the safety performance of the battery. The aspect ratio of the battery refers to the ratio of the width (for square batteries) or diameter (for cylindrical batteries) of the battery to the height. This ratio can affect the thermal distribution and pressure accumulation during the charging and discharging process of the battery. Designers need to consider the impact of this ratio on the battery safety. Therefore, when designing the battery, the explosion-proof valve and the cooling system need to be designed accordingly. The aspect ratio of the battery will affect the size, design, and installation position of the explosion-proof valve to ensure effective pressure balance under all normal and abnormal operating conditions. In the related art, the explosion-proof valve of the battery is usually located on the side or top of the battery to release pressure when the internal pressure of the battery is too high. Therefore, setting the ratio of h1 to h2 to 40% - 60% in the above embodiments can effectively ensure the safety of battery use.

[0049] In some examples, the end cap 1 can be made of aluminum material. Among them, aluminum has a low density. The end cap 1 made of aluminum can reduce the weight of the battery, and the aluminum material has good thermal conductivity, which also helps the battery to dissipate heat, thereby maintaining the working temperature of the battery within a suitable range and improving the performance and lifespan of the battery. In addition, a dense oxide film is easily formed on the surface of aluminum. This oxide film can protect the aluminum material from further oxidation, improve the corrosion resistance, and the aluminum material is easy to process and form, and can adapt to different battery designs and application requirements.

[0050] In the end cap assembly of the battery involved in the present application, it includes an end cap 1 and a waterproof and breathable membrane 2. Among them, the end cap 1 is provided with a pressure relief hole 11, and the waterproof and breathable membrane 2 is used to cover the pressure relief hole 11. On the one hand, the gas released during the battery cycle can be smoothly discharged through the waterproof and breathable membrane 2 to balance the internal and external air pressures of the battery, thereby avoiding excessive internal pressure of the battery and affecting the safety performance of the battery. On the other hand, when the battery undergoes thermal runaway or other situations, resulting in the internal pressure of the battery reaching the preset value, since the bursting pressure of the waterproof and breathable membrane 2 is less than the bursting pressure of the end cap 1, the waterproof and breathable membrane 2 will rupture to form a pressure relief channel communicating with the pressure relief hole 11, thereby quickly discharging the gas inside the battery and preventing the battery from exploding and other dangers. And compared with the traditional aluminum sheet explosion-proof valve, the risk of the waterproof and breathable membrane 2 causing harm to people or external equipment when rupturing and spraying is lower, and it is safer to use. In addition, the setting of the thinning area 13 can also deform when the internal pressure of the battery is too high, and then also produce a certain extrusion on the waterproof and breathable membrane 2, promoting the rupture of the waterproof and breathable membrane 2 to release pressure, further improving the safety performance of the battery.

[0051] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0052] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0053] Among the embodiments, implementation manners and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0054] The above are only the preferred embodiments of the present application and do not impose any form of limitation on the present application. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

[0055] Although the present utility model has been specifically described above in conjunction with the accompanying drawings and implementation manners, it can be understood that the above description does not limit the present utility model in any form. Those skilled in the art can make deformations and changes to the present utility model according to needs without departing from the essence and scope of the present utility model, and these deformations and changes all fall within the scope of the present utility model.

Claims

1. A battery end cap assembly, characterized in that: include: An end cover, wherein the end cover is provided with a pressure relief hole, the end cover comprises a main body and a thinned area, the thinned area surrounds the pressure relief hole, the main body is arranged on a side of the thinned area away from the pressure relief hole, and the thickness of the thinned area is less than the thickness of the main body; A waterproof breathable membrane is connected to the thinned area, the waterproof breathable membrane covers the pressure relief hole and is used to allow gas to pass through the waterproof breathable membrane, and the bursting pressure of the waterproof breathable membrane is less than the bursting pressure of the end cover.

2. The end cap assembly of a battery according to claim 1, characterized in that: The end cover is used to cover the battery cell of the battery; The main body includes a first side facing away from the battery core, the thinned area includes a second side facing away from the battery core, and the waterproof breathable membrane includes a third side facing away from the battery core; The second side surface and the third side surface are located on a side of the plane where the first side surface is located and facing the battery core.

3. The end cap assembly of the battery according to claim 2, characterized in that: The second side surface and the third side surface are on the same plane; or, The second side surface is located between the first side surface and the third side surface.

4. The end cap assembly of a battery according to claim 1, characterized in that: The pressure resistance value of the thinned area is greater than the pressure resistance value of the waterproof breathable membrane.

5. The end cap assembly of the battery according to claim 4, characterized in that: The pressure resistance value of the thinning zone is a1, and the value range of a1 is: 0.9MPa≤d1≤2MPa; The pressure resistance value of the waterproof breathable membrane is a2, and the value range of a2 is: 0.7MPa≤a2<0.9MPa.

6. The end cap assembly of a battery according to claim 1, characterized in that: The thickness of the thinned area is greater than or equal to the thickness of the waterproof breathable membrane.

7. The end cap assembly of a battery according to claim 1, characterized in that: The ratio of the thickness of the thinned area to the thickness of the end cover is between 50% and 80%.

8. The end cap assembly of a battery according to claim 1, characterized in that: The thickness of the waterproof and breathable membrane is between 0.1 mm and 0.5 mm.

9. The end cap assembly of a battery according to claim 1, characterized in that: The thinned area is interference fit with the waterproof breathable membrane.

10. A battery, characterized in that: An end cap assembly comprising a battery as claimed in any one of claims 1 to 9.

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