A breathable pressure-relieving tab, a pressure-relieving device and a soft-pack battery

Abstract

The present invention discloses a breathable pressure-relieving tab, a pressure-relieving device and a soft-pack battery. The pressure-relieving device includes a base and a highly breathable functional film. A second-order counterbore is formed in the base, and a breathable first backing is attached to the stepped platform of the second-order counterbore. The first backing shields the stepped opening of the second-order counterbore. The highly breathable functional film is attached to the top of the base, and the highly breathable functional film shields the upper opening of the second-order counterbore. The present invention realizes the function of exhausting and relieving pressure for the soft-pack battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, specifically relates to the fields of lithium-ion batteries and sodium-ion batteries, and particularly relates to a breathable pressure-relieving tab, a pressure-relieving device and a soft-pack battery. Background Art

[0002] Existing tab devices generally include metal components and insulating films, and no exhaust channels are designed. When the tab device is encapsulated with an Al Pocket bag to form a battery (including lithium-ion batteries, sodium-ion batteries, etc.), side reactions will occur during the cyclic use of the battery. The occurrence of side reactions generally involves gas generation. As the gas accumulates continuously, the pressure inside the battery will become higher and higher. When it reaches a certain limit value, it will break through the weak link of the battery shell Al pocket bag, resulting in leakage of the battery core; in severe cases, it will pose a safety hazard, causing immeasurable losses. Therefore, the pressure release inside the battery is of great significance for its safety. For hard-shell batteries, an explosion-proof valve can be set on the cover plate. When the internal pressure of the battery reaches a certain threshold value, the explosion-proof valve is triggered to achieve the purpose of pressure relief. For soft-pack batteries, since the Al Foil encapsulation bag shell is a soft material, it is difficult to realize the design, assembly and function of the explosion-proof valve; but exhaust pressure relief is also an urgent problem to be solved for soft-pack batteries currently.

[0003] Existing conventional tab components are metal conductors and insulating films, which are heat-sealed and bonded together at high temperature, and the bonding strength can reach 2 N / mm. The insulating film is made of polypropylene material. When the thickness of the insulating film is 100 μm, the amount of CO2 that can permeate through it is generally about 1500 ml / (m2•24 h•0.1 MPa); since the metal conductor component of the existing tab does not have an exhaust channel, when the tab is encapsulated with an Al pocket encapsulation bag, the thickness through which the gas needs to permeate is the height of the insulating film, generally 10 mm or more. Therefore, the insulating film after top-sealing encapsulation appears as an air-impermeable film. However, during the cyclic use of the battery core, the pressure inside the battery gradually accumulates and cannot be released; when the internal pressure reaches a certain limit value, it will break through the weakest link of the encapsulation bag, such as the side seal, or the top seal, or the R corner of the Al pocket encapsulation bag, all of which will cause battery leakage, resulting in significant losses. Therefore, it is urgent to realize the function of exhaust pressure relief for soft-pack batteries. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a breathable pressure-relieving tab, a pressure-relieving device and a soft-pack battery aiming at the deficiencies in the above-mentioned existing technologies, and realizes the function of exhaust pressure relief for soft-pack batteries.

[0005] The first aspect of the present invention discloses a pressure relief device for breathable and pressure-relieving tabs, including a base and a highly breathable functional film. A second-order counterbore is formed on the base, and a breathable first backing is attached to the stepped platform of the second-order counterbore. The first backing shields the stepped opening of the second-order counterbore. The highly breathable functional film is attached to the top of the base, and the highly breathable functional film shields the upper opening of the second-order counterbore.

[0006] For the above-mentioned pressure relief device for breathable and pressure-relieving tabs, the highly breathable functional film is attached to the top of the base through a first bottom film.

[0007] The second aspect of the present invention discloses a breathable and pressure-relieving tab. A base ventilation opening and a gas guiding channel are formed on the surface of the tab. The gas guiding channel is communicated with the base ventilation opening, and the pressure relief device as described in the first aspect is installed on the base ventilation opening. The base in the pressure relief device is attached to the periphery of the base ventilation opening to form a shield for the base ventilation opening.

[0008] For the above-mentioned breathable and pressure-relieving tab, a cover sheet is provided on the gas guiding channel.

[0009] For the above-mentioned breathable and pressure-relieving tab, an annular second backing is arranged in the base ventilation opening.

[0010] For the above-mentioned breathable and pressure-relieving tab, a perforated groove is formed at the bottom of the gas guiding channel.

[0011] For the above-mentioned breathable and pressure-relieving tab, the base in the pressure relief device is attached to the periphery of the base ventilation opening through a second bottom film.

[0012] The third aspect of the present invention discloses a soft-pack battery, including the breathable and pressure-relieving tab as described in the second aspect and a battery pack. The breathable and pressure-relieving tab is installed at the sealing position of the battery pack through a top sealing edge, and the rear end of the gas guiding channel of the breathable and pressure-relieving tab extends into the battery pack.

[0013] For the above-mentioned soft-pack battery, the top sealing edge is a sealing interface formed by the fusion of a sealing functional film material and an Al Pocket packaging bag.

[0014] Compared with the prior art, the present invention has the following advantages: The gas inside the battery pack can be discharged through the base ventilation opening and the gas guiding channel formed on the surface of the tab to achieve the purpose of pressure reduction. During the exhaust and pressure relief process, the existence of the highly breathable functional film ensures that no electrolyte leaks out under the breathable function.

[0015] The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the pressure relief device.

[0017] Figure 2 ForFigure 1 A - A cross - sectional view.

[0018] Figure 3 It is a schematic structural diagram of a breathable pressure - relief tab.

[0019] Figure 4 It is Figure 3 B - B cross - sectional view.

[0020] Figure 5 It is Figure 4 Enlarged view of part A in

[0021] Figure 6 It is Figure 4 Enlarged view of part B in

[0022] Figure 7 It is a schematic structural diagram of a soft - pack battery encapsulating a breathable pressure - relief tab.

[0023] Explanation of reference numerals:

[0024] Detailed implementation manners

[0025] Example 1

[0026] As Figure 1 and Figure 2 shown, a pressure - relief device for a breathable pressure - relief tab includes a base 1 and a high - breathable functional film 2. A second - order counterbore 4 is provided on the base 1, and a breathable first back - lining 3 is attached to the step of the second - order counterbore 4. The first back - lining 3 covers the step opening of the second - order counterbore 4. The high - breathable functional film 2 is attached to the top of the base 1, and the high - breathable functional film 2 covers the upper opening of the second - order counterbore 4.

[0027] It should be noted that the first back - lining 3 can have any thickness and any shape (preferably 0.5 mm to 1.0 mm), the outer dimension is not larger than the counterbore of the base 1, and the material is a high - breathable fluorine - containing material.

[0028] The thickness of the highly breathable functional film 2 is not less than 30 μm (preferably 150 μm to 200 μm), and its shape can be circular, square, polygonal, etc. The outer dimension is not larger than that of the base 1, and it can completely cover the air-permeable channels of the base 1. The material is mainly polyolefin; the structure is a single-layer or multi-layer structure. For the single-layer structure, polyolefin materials can be used, which have a strong bonding strength with PP-based materials; modified polyolefin materials containing polar groups such as carboxyl, hydroxyl, double bond, carbonyl, amino, etc. can also be used. Its melting point is generally 110°C to 170°C, and it has a strong adhesion to metals. In the multi-layer structure, at least one layer of polyolefin material can have a strong bonding strength with PP-based film materials; or at least one layer of modified polyolefin material containing polar groups such as carboxyl, hydroxyl, double bond, carbonyl, amino, etc. Its melting point is generally 110°C to 170°C, and it has a strong adhesion to metals.

[0029] The base 1 can have any thickness (preferably 0.1 mm to 1.0 mm) and any size, and its shape can be circular, square, polygonal, etc.; the material can be metal materials such as high-purity aluminum or nickel-plated aluminum, and high-purity copper or nickel-plated copper, and high-purity nickel, and copper-aluminum alloy, and aluminum-nickel alloy, etc. metal materials; it can also be polymer materials such as polyolefin materials like PP-based film materials or sheets.

[0030] In this embodiment, the highly breathable functional film 2 is attached to the top of the base 1 through the first bottom film 5.

[0031] It should be noted that the first bottom film 5 can have any thickness and any shape (preferably 50 μm to 100 μm), the outer dimension is not larger than that of the base 1, and the material is a modified polyolefin material. It has a strong bonding adhesion to metals or a strong bonding force with polyolefin materials such as PP-based materials.

[0032] Embodiment 2

[0033] As Figure 3 — Figure 6 As shown, a breathable and pressure-relieving tab 6 has a base air-permeable port 7 and a gas guiding channel 8 formed on the surface of the tab 6. The gas guiding channel 8 is communicated with the base air-permeable port 7, and the pressure-relieving device described in Embodiment 1 is installed on the base air-permeable port 7. The base 1 in the pressure-relieving device is attached to the periphery of the base air-permeable port 7 to form an occlusion of the base air-permeable port 7.

[0034] It should be noted that the tab 6 is a metal conductor, which can have any size, preferably a thickness of 0.4 mm to 1.5 mm and a width of 20 mm to 200 mm. The material is high-purity aluminum or nickel-plated aluminum, and high-purity copper or nickel-plated copper, and high-purity nickel, and copper-aluminum alloy, and aluminum-nickel alloy, etc. metal materials; its main function is as a carrier for energy transfer;

[0035] In this embodiment, a cover sheet 9 is provided on the gas guiding channel 8.

[0036] It should be noted that the material of the cover sheet 9 can be a polymer material or a metal material (preferably consistent with the conductor of the tab 6, such as high-purity aluminum and nickel-plated copper metal); it can be of any size, and the thickness is preferably 0.1 mm to 0.3 mm; the shape can be circular, square, polygonal, or other special shapes, etc.

[0037] In this embodiment, a ring-shaped second backing 10 is arranged in the base air vent 7. The second backing 10 can be of any thickness and any shape, and the material is a highly breathable fluorine-containing material. The setting of the second backing 10 can play a supporting role for the tab 6, so that the tab 6 is not prone to large deformation. The second backing 10 can also adsorb free electrolyte to prevent the electrolyte from remaining in the air vent for a long time and drying out and crystallizing, thereby blocking the base air vent 7.

[0038] In this embodiment, a perforated groove 11 is formed at the bottom of the gas guiding channel 8. The perforated groove 11 can be of any size, and the width is preferably 0.1 mm to 0.6 mm.

[0039] It should be noted that the purpose of setting the perforated groove 11 is that when the tab 6 is heated, the second backing 10 may be deformed by heat. The establishment of the perforated groove 11 can eliminate the force exerted on the tab 6 by the deformation of the second backing 10, achieving the effect of a shrinkage joint.

[0040] In addition, the purpose of setting the perforated groove 11 is that when the tab 6 is stamping formed, the gas guiding channel 8 has a certain stamping depth, and the stamping allowance generated by the stamping depth is likely to cause the deformation of the tab 6; after the perforated groove 11 is opened, the stamping allowance can overflow through the perforated groove 11, thereby eliminating the deformation of the tab 6.

[0041] In this embodiment, the base 1 in the pressure relief device is attached to the periphery of the base air vent 7 through the second bottom film 12.

[0042] Embodiment 3

[0043] As Figure 7 shown, a soft package battery includes the breathable pressure relief tab 6 and the battery pack 13 described in Embodiment 2. The breathable pressure relief tab 6 is installed at the sealing position of the battery pack 13 through the top sealing edge 15, and the rear end of the gas guiding channel 8 of the breathable pressure relief tab 6 extends into the battery pack 13.

[0044] In this embodiment, the top sealing edge 15 is a sealing interface formed by fusing the sealing functional film material 14 and the Al Pocket packaging bag.

[0045] It should be noted that during use, when gas is generated due to the occurrence of side reactions inside the battery pack 13, the gas enters through the rear end of the gas conduction channel 8 of the breathable pressure relief tab 6, is discharged from the front end of the gas conduction channel 8 into the base breathable port 7, and finally leaks out through the highly breathable functional membrane 2 on the pressure relief device.

[0046] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural changes made to the above embodiments based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An air-permeable and pressure-relieving tab, characterized in that, The surface of the tab is provided with a base air vent and an air guiding channel. The air guiding channel is communicated with the base air vent, and a pressure relief device is installed on the base air vent. The base in the pressure relief device is attached to the periphery of the base air vent to form an occlusion of the base air vent. The pressure relief device includes a base and a highly breathable functional film. A second-order counterbore is formed in the base, and the highly breathable functional film is attached to the top of the base to form an occlusion of the upper opening of the second-order counterbore. A breathable first back lining is attached to the stepped platform of the second-order counterbore to form an occlusion of the stepped opening of the second-order counterbore. The highly breathable functional film is attached to the top of the base through a first bottom film. An annular second back lining is arranged in the base air vent. The material of the second back lining is a highly breathable fluorine-containing material, which is used to support the tab and adsorb free electrolyte. A perforated groove is formed at the bottom of the air guiding channel, and the perforated groove is used to eliminate the force applied to the tab when the second back lining is deformed.

2. The air-permeable and pressure-relieving tab according to claim 1, characterized in that, A cover plate is arranged on the air guiding channel.

3. The breathable and pressure-relieving tab according to claim 1, characterized in that, The base in the pressure relief device is attached to the periphery of the base air vent through a second bottom film.

4. A soft-pack battery, characterized in that, It includes the breathable pressure relief tab and the battery pack according to any one of claims 1-3. The breathable pressure relief tab is installed at the sealing position of the battery pack through a top sealing edge, and the rear end of the air guiding channel of the breathable pressure relief tab extends into the battery pack.

5. A soft-pack battery according to claim 4, characterized in that, The top sealing edge is a sealing interface formed by the fusion of the sealing functional film material on the tab and the Al Pocket packaging bag.

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