Breathable pressure relief tab, pressure relief device, and pouch battery

Abstract

Disclosed are a breathable pressure relief tab, a pressure relief device, and a pouch battery. The pressure relief device comprises a base and a high-breathability functional film; a two-step counterbore is formed on the base; a breathable first backing is attached to a stepped platform of the two-step counterbore, and the first backing covers a stepped opening of the two-step counterbore; the high-breathability functional film is attached to the top of the base, and the high-breathability functional film covers an upper opening of the two-step counterbore. The present invention achieves gas venting and pressure relief functions for the pouch battery.

Description

A breathable pressure relief tab, a pressure relief device, and a soft-pack battery Technical Field

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

[0002] Existing tab assemblies typically consist of metal components and an insulating film, lacking a venting channel. When these tab assemblies are packaged with an Al Pocket to create a battery (including lithium-ion and sodium-ion batteries), side reactions can occur during battery cycling. These reactions are typically accompanied by gas generation. As gas accumulates, the internal pressure of the battery increases. When this gas reaches a certain threshold, it can break through the weak links in the Al Pocket, causing leakage from the battery cell. In severe cases, this can pose a safety hazard and result in immeasurable damage. Therefore, internal pressure relief is crucial for battery safety. For hard-shell batteries, an explosion-proof valve can be installed on the cover. When the internal pressure reaches a certain threshold, the valve is activated to release pressure. However, for soft-pack batteries, the Al Foil packaging shell is made of a soft material, making the design, assembly, and function of the explosion-proof valve difficult to implement. However, venting and pressure relief are also a pressing issue for soft-pack batteries.

[0003] Conventional tab components consist of a metal conductor and an insulating film, bonded together through high-temperature heat sealing, achieving a bond strength of 2N / mm. The insulating film is made of polypropylene. When the insulating film is 100µm thick, it typically allows approximately 1500ml / (m²·24h·0.1MPa) of CO₂ to pass through. Because the metal conductor components of existing tabs lack venting channels, the thickness of the insulating film required for gas to pass through after the tabs are packaged in an Al pocket packaging bag is equal to the height of the insulating film, typically 10mm or more. Consequently, the insulating film becomes impermeable after top-seal packaging. However, during battery cell cycling, internal pressure gradually accumulates and cannot be released. When the internal pressure reaches a certain limit, it can break through the weakest points of the packaging bag, such as the side seals, top seals, or even the corners of the Al pocket packaging bag, causing battery leakage and significant losses. Therefore, there is an urgent need for venting and pressure relief functions for soft-pack batteries.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a breathable and pressure-relieving tab and a pressure-relieving device and a soft-pack battery, thereby realizing the function of exhausting and relieving pressure of the soft-pack battery.

[0006] The first aspect of the present invention discloses a pressure relief device for a breathable and pressure-relieving tab, comprising a base and a highly breathable functional membrane, wherein a second-step countersunk hole is provided on the base, and a breathable first backing is affixed to the stepped platform of the second-step countersunk hole, and the first backing forms a shield for the stepped mouth of the second-step countersunk hole, and a highly breathable functional membrane is affixed to the top of the base, and the highly breathable functional membrane forms a shield for the upper opening of the second-step countersunk hole.

[0007] In the above-mentioned pressure relief device for the breathable and pressure-relieving tab, the highly breathable functional membrane is attached to the top of the base through the first bottom membrane.

[0008] The second aspect of the present invention discloses a breathable and pressure-relieving tab, wherein a base air vent and an air guide channel are provided on the surface of the tab, wherein the air guide channel is connected to the base air vent, and a pressure relief device as described in the first aspect is installed on the base air vent, wherein the base in the pressure relief device is attached to the periphery of the base air vent to form a shield for the base air vent.

[0009] The above-mentioned breathable and pressure-relieving tab has a cover sheet on the air guide channel.

[0010] The above-mentioned breathable and pressure-relieving tab has an annular second backing provided in the base air vent.

[0011] The above-mentioned breathable and pressure-relieving tab has a perforated groove at the bottom of the air guide channel.

[0012] The above-mentioned breathable and pressure-relieving tab, the base in the pressure-relieving device is attached to the periphery of the base's air permeability through the second bottom film.

[0013] The third aspect of the present invention discloses a soft-pack battery, comprising a breathable and pressure-relieving tab and a battery pack as described in the second aspect, wherein the breathable and pressure-relieving tab is installed at the battery pack seal through a top seal, and the rear end of the air guide channel of the breathable and pressure-relieving tab extends into the interior of the battery pack.

[0014] In the above-mentioned soft-pack battery, the top seal is a sealing interface where the sealing functional film material is fused with the Al Pocket packaging bag.

[0015] Compared with the prior art, the present invention has the following advantages: the base vents and air guide channels opened on the surface of the tab allow the gas inside the battery pack to escape, thereby achieving the purpose of reducing pressure. During the exhaust and pressure relief process, the presence of the highly breathable functional membrane ensures that no electrolyte will leak out under the breathable function.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a pressure relief device.

[0018] FIG2 is a cross-sectional view taken along line AA of FIG1 .

[0019] FIG3 is a schematic diagram of the structure of the air-permeable and pressure-relieving tab.

[0020] FIG4 is a cross-sectional view taken along line BB in FIG3 .

[0021] FIG5 is an enlarged view of point A in FIG4 .

[0022] FIG6 is an enlarged view of point B in FIG4 .

[0023] Figure 7 is a schematic diagram of the structure of a soft-pack battery with encapsulated breathable and pressure-relieving tabs.

[0024] Explanation of the accompanying symbols: 1—base; 2—highly breathable functional membrane; 3—first backing; 4—second-order countersunk hole; 5—first bottom membrane; 6—tab; 7—base vent; 8—air guide channel; 9—cover sheet; 10—second backing; 11—perforation groove; 12—second bottom membrane; 13—battery pack; 14—sealing functional membrane; 15—top seal. DETAILED DESCRIPTION

[0025] Example 1

[0026] As shown in Figures 1 and 2, a pressure relief device for a breathable and pressure-relieving tab includes a base 1 and a highly breathable functional membrane 2. A second-step countersunk hole 4 is provided on the base 1. A breathable first backing 3 is attached to the stepped platform of the second-step countersunk hole 4. The first backing 3 blocks the stepped opening of the second-step countersunk hole 4. A highly breathable functional membrane 2 is attached to the top of the base 1. The highly breathable functional membrane 2 blocks the upper opening of the second-step countersunk hole 4.

[0027] It should be noted that the first backing 3 can be of any thickness and shape (preferably 0.5 mm to 1.0 mm), with an outer dimension no larger than the countersunk hole of the base 1 , and is made of a highly breathable fluorine-containing material.

[0028] The highly breathable functional membrane 2 has a thickness of no less than 30 μm (preferably 150 μm to 200 μm) and can be shaped like a circle, square, or polygon. Its dimensions should be no larger than those of the base 1 and should completely cover the breathable passages of the base 1. It is primarily made of polyolefins and can be either single-layer or multi-layer. Single-layer structures can use polyolefins, which exhibit strong adhesion to polypropylene (PP)-based materials. Modified polyolefins containing polar groups such as carboxyl, hydroxyl, double bonds, carbonyl, and amino groups can also be used. These materials typically have a melting point of 110°C to 170°C, providing strong adhesion to metals. Multi-layer structures can include at least one layer of polyolefin material, which exhibits strong adhesion to PP-based membranes. Alternatively, modified polyolefins containing polar groups such as carboxyl, hydroxyl, double bonds, carbonyl, and amino groups can also be used. These materials typically have a melting point of 110°C to 170°C, providing strong adhesion to metals.

[0029] The base 1 can be of any thickness (preferably 0.1mm to 1.0mm) and any size, and can be round, square, polygonal, etc.; the material can be metal materials, such as high-purity aluminum or aluminum-nickel-plated, high-purity copper or copper-nickel-plated, high-purity nickel, copper-aluminum alloy, aluminum-nickel alloy and other metal materials; it can also be a polymer material, such as PP film or sheet and other polyolefin materials.

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

[0031] It should be noted that the first base film 5 can be of any thickness and shape (preferably 50 μm to 100 μm), with dimensions no larger than the base 1, and is made of a modified polyolefin material that has strong adhesion to metals or to polyolefin materials such as PP.

[0032] Example 2

[0033] As shown in Figures 3 to 6, a breathable and pressure-relieving tab 6 is provided, and a base air vent 7 and an air guide channel 8 are provided on the surface of the tab 6. The air guide channel 8 is connected to the base air vent 7. The pressure relief device described in Example 1 is installed on the base air vent 7. The base 1 in the pressure relief device is attached to the periphery of the base air vent 7 to form a shield for the base air vent 7.

[0034] It should be noted that the tab 6 is a metal conductor and can be of any size, preferably with 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 aluminum-nickel-plated, high-purity copper or copper-nickel-plated, high-purity nickel, copper-aluminum alloy, aluminum-nickel alloy and other metal materials; its main function is to be a carrier of energy transfer;

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

[0036] It should be noted that the cover plate 9 can be made of a polymer material or a metal material (preferably consistent with the conductor of the tab 6, such as high-purity aluminum and copper-plated nickel metal); can be of any size, preferably 0.1mm to 0.3mm thick; and can be shaped like a circle, square, polygon, or other special shapes.

[0037] In this embodiment, a ring-shaped second backing 10 is provided in the base vent 7. The second backing 10 can be of any thickness and shape and is made of a highly breathable fluorine-containing material. The second backing 10 can support the tab 6, making it less likely for the tab 6 to deform significantly. The second backing 10 can also absorb free electrolyte to prevent the electrolyte from remaining in the vent for a long time and drying up and crystallizing, thereby blocking the base vent 7.

[0038] In this embodiment, a perforated groove 11 is provided at the bottom of the air guide channel 8. The perforated groove 11 can be of any size, preferably with a width of 0.1 mm to 0.6 mm.

[0039] It should be noted that the purpose of providing the perforation groove 11 is that when the tab 6 is heated, the second backing 10 may be deformed due to the heat. The establishment of the perforation groove 11 can eliminate the force applied to the tab 6 by the deformation of the second backing 10, thereby achieving the effect of a shrinkage seam.

[0040] In addition, the purpose of providing the perforation groove 11 is that when the tab 6 is being stamped, the air guide channel 8 has a certain stamping depth, and the stamping margin generated by the stamping depth can easily cause deformation of the tab 6; after the perforation groove 11 is opened, the stamping margin can overflow through the perforation 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 vent 7 through the second bottom film 12 .

[0042] Example 3

[0043] As shown in Figure 7, a soft-pack battery includes the breathable and pressure-relieving tab 6 and the battery pack 13 described in Example 2. The breathable and pressure-relieving tab 6 is installed at the seal of the battery pack 13 through the top sealing edge 15, and the rear end of the air guide channel 8 of the breathable and pressure-relieving tab 6 extends into the interior of the battery pack 13.

[0044] In this embodiment, the top sealing edge 15 is a sealing interface where the sealing functional film 14 and the Al Pocket packaging bag are fused together.

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

[0046] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A pressure relief device for a breathable pressure relief tab, characterized in that: The invention comprises a base and a highly breathable functional film, wherein the base is provided with a second-order countersunk hole, and the top of the base is affixed with the highly breathable functional film, and the highly breathable functional film blocks the upper opening of the second-order countersunk hole.

2. A pressure relief device for a ventilated pressure relief tab according to claim 1, characterized in that: A breathable first backing is attached to the stepped platform of the second-order countersunk hole, and the first backing forms a shield for the stepped opening of the second-order countersunk hole.

3. A pressure relief device for a ventilated pressure relief tab according to claim 1, characterized in that: The highly breathable functional film is attached to the top of the base through the first bottom film.

4. A breathable pressure relief ear, characterized in that: A base air vent and an air guide channel are provided on the surface of the pole ear, the air guide channel is connected to the base air vent, and a pressure relief device as described in claim 1, 2 or 3 is installed on the base air vent, and the base in the pressure relief device is attached to the periphery of the base air vent to form a shield for the base air vent.

5. A breathable and pressure-relieving tab according to claim 4, characterized in that: The air guide channel is covered with a cover sheet.

6. A breathable and pressure-relieving tab according to claim 4, characterized in that: An annular second backing is arranged in the air permeable opening of the base.

7. A breathable and pressure-relieving tab according to claim 4, characterized in that: A perforated groove is provided at the bottom of the air guide channel.

8. A breathable and pressure-relieving tab according to claim 4, characterized in that: The base in the pressure relief device is attached to the periphery of the air permeable opening of the base through the second bottom film.

9. A soft pack battery, characterized in that: It comprises a breathable and pressure-relieving electrode ear and a battery pack as claimed in any one of claims 4 to 8, wherein the breathable and pressure-relieving electrode ear is installed at the sealing opening of the battery pack through a top sealing edge, and the rear end of the air guide channel of the breathable and pressure-relieving electrode ear extends into the interior of the battery pack.

10. A soft pack battery according to claim 9, characterized in that: The top sealing edge is a sealing interface where the sealing functional film material is fused with the Al Pocket packaging bag packaging.

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