Breathable tab, preparation method of breathable tab and soft package battery

Abstract

The invention provides a breathable tab, a preparation method of the breathable tab and a soft package battery. The breathable tab comprises a conductive base material, the conductive base material comprises conductive parts arranged at the two ends and an air guide part arranged in the middle, a breathable through hole is formed in the air guide part, and a breathable filling layer is arranged in the breathable through hole; the air guide rubber film covers the periphery of the air guide part and covers the ventilation through hole. According to the breathable tab disclosed by the invention, gas in the soft package battery can be discharged out of the soft package battery in a one-way manner, so that an effect of cleaning the internal atmosphere of the battery cell of the soft package battery is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to a breathable tab, a method for preparing the breathable tab, and a soft-pack battery. Background Art

[0002] Clean electric energy storage devices are an important component of new energy. Taking lithium-ion batteries, which have the largest output, as an example, current lithium-ion batteries have different material systems, different manufacturing processes, different electrical performance ranges, different battery cell models, and different battery cell shells. The usage scenarios range from Bluetooth headsets and smart wearable devices to electric vehicles and electric ships. Regardless of the usage scenario of lithium-ion batteries, during the entire life cycle of the battery and during the continuous charging and discharging of the battery, gas will be intermittently generated inside the battery. The increasing internal pressure in the battery will deteriorate the battery's electrical performance, affect the battery's service life, increase safety risks, and indirectly increase the cost of using the battery.

[0003] In order to reduce the problem of gas production inside the battery, the focus is generally on the modification of battery materials, optimization of battery formulas, improvement of manufacturing processes, etc. However, these increase the cost of the battery and will also affect the electrical performance of other aspects (such as reduced energy density or deterioration of low-temperature rate performance, etc.). Packaging materials are important components of lithium batteries, which play a sealing role in isolating the inside of the lithium battery from the external environment. Different packaging materials divide lithium batteries into square aluminum shell batteries, cylindrical batteries, soft-pack batteries, etc. In square aluminum shell batteries, exhaust valves are usually set to discharge the gas inside the battery cell, so as to achieve a clean atmosphere inside the battery cell. However, for soft-pack batteries, due to the strong integration of the aluminum-plastic film of the packaging material, it is impossible to set an exhaust valve like the square aluminum shell battery, because it will greatly reduce the sealing effect.

[0004] The tab is an important part of the soft-pack battery. It seals the battery cell in the top seal area and connects the internal and external currents of the battery. It is a part that can be well connected to the aluminum-plastic film and can be deeply processed to add other functions. The conventional tab is composed of tab glue and a metal substrate. The thickness of the tab glue is usually between tens and hundreds of microns and has a certain air permeability. However, in the actual connection direction between the inside and outside of the battery cell, the distance that the gas needs to pass is the width of the tab glue, which is tens to hundreds of times the thickness of the tab glue. Therefore, the air permeability is almost gone, and it cannot play a role in purifying the atmosphere inside the battery cell. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a breathable tab, a method for preparing a breathable tab, and a soft-pack battery, so as to solve the problem of poor tab permeability of existing soft-pack batteries.

[0006] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a breathable electrode ear, including: a conductive substrate, the conductive substrate including a conductive part arranged at both ends and an air-conducting part arranged in the middle, and a breathable through hole is formed on the air-conducting part; a breathable filling layer, the breathable filling layer is arranged in the breathable through hole; and an air-conducting adhesive film, the air-conducting adhesive film is coated on the periphery of the air-conducting part and covers the breathable through hole.

[0007] In some embodiments of the first aspect of the present application, the conductive substrate is made of metal material.

[0008] In some embodiments of the first aspect of the present application, the number of the breathable through holes is one or more; the number of the breathable filling layers is the same as the number of the breathable through holes.

[0009] In some embodiments of the first aspect of the present application, a positioning and limiting groove is provided at the boundary of the ventilation hole so that the breathable filling layer and the ventilation hole can maintain a fixed position.

[0010] In some embodiments of the first aspect of the present application, the number of layers of the air-conducting adhesive film is at least two.

[0011] In some embodiments of the first aspect of the present application, when the number of layers of the air-conducting adhesive film is two, the air-conducting adhesive film is composed of an outer layer and an inner layer; wherein the inner layer is coated on the periphery of the air-conducting part; and the outer layer is coated on the outer surface of the inner layer.

[0012] In some embodiments of the first aspect of the present application, the inner layer is made of modified polypropylene, polyacrylic acid, and polyethylene copolymers containing polar groups; the polar groups include carbonyl, amino, and hydroxyl groups; and the outer layer is a polymer film composited with modified polypropylene, polyacrylic acid, and polyolefin elastomer.

[0013] In some embodiments of the first aspect of the present application, the breathable filling layer is composited by a water-absorbent material and a foam substrate.

[0014] To achieve the above-mentioned purpose and other related purposes, the second aspect of the present application provides a method for preparing a breathable electrode ear, comprising: providing a conductive substrate; wherein the conductive substrate comprises a conductive portion arranged at both ends and an air-conducting portion arranged in the middle; forming a breathable through hole on the air-conducting portion of the conductive substrate; arranging a breathable filling layer in the breathable through hole; and using an air-conducting adhesive film to cover the periphery of the air-conducting portion and seal the breathable through hole.

[0015] To achieve the above-mentioned purpose and other related purposes, the third aspect of the present application provides a soft-pack battery, which is provided with a breathable pole ear as described above; the breathable pole ear leads the electrode of the soft-pack battery out of the soft-pack battery; wherein, the aluminum-plastic film of the soft-pack battery is used to top seal the gas-conducting adhesive film and the corresponding gas-conducting part, and the upper and lower sealing seams formed by the aluminum-plastic film and the upper and lower layers of the gas-conducting adhesive film are located on the upper and lower sides of the gas-permeable through hole.

[0016] As described above, the ventilated tab, the method for preparing the ventilated tab, and the soft-pack battery of the present application have the following beneficial effects:

[0017] The breathable pole ear of the present application allows the gas in the soft-pack battery to be discharged to the outside of the soft-pack battery in a unidirectional manner, thereby playing a role in purifying the atmosphere inside the soft-pack battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a schematic top view of a breathable tab in one embodiment of the present application.

[0019] Figure 2 Shown is a main cross-sectional schematic diagram of a breathable electrode in one embodiment of the present application.

[0020] Figure 3 Shown is a schematic side cross-sectional view of a breathable electrode ear in one embodiment of the present application.

[0021] Figure 4 Shown is a schematic diagram of the gas exhaust direction of a soft-pack battery in one embodiment of the present application.

[0022] Figure 5 Shown is a schematic diagram of the gas exhaust direction of a soft-pack battery in the prior art.

[0023] Figure 6 Shown is a schematic flow chart of a method for preparing a breathable tab in one embodiment of the present application. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] In the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit the difference.

[0026] It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" represent examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0027] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, ab, ac, bc or abc, where a, b, c can be single or multiple.

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution in the embodiments of the present invention is further described in detail through the following embodiments and in combination with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0029] like Figures 1 to 4 As shown, it is a schematic diagram of the structure of the breathable electrode ear in an embodiment of the present invention.

[0030] The ventilated tab is applied to a soft-pack battery and includes:

[0031] A conductive substrate 1, wherein the conductive substrate 1 comprises conductive portions arranged at both ends and an air guide portion arranged in the middle, and the air guide portion is formed with air-permeable through holes 11;

[0032] A breathable filling layer 2, wherein the breathable filling layer 2 is disposed in the breathable through hole 11;

[0033] The air-conducting adhesive film 3 is coated on the periphery of the air-conducting portion and covers the air-permeable through hole 11 .

[0034] In one embodiment, the conductive substrate is made of metal material, specifically, copper, aluminum, nickel-plated copper, silver, nickel or other metal materials with good conductivity.

[0035] In one embodiment, the surface of the conductive substrate can be modified with polar functionality by deposition of organic amines or inorganic transition metal oxides. It should be noted that polar functional modification of metal materials refers to modifying the surface of metal materials by chemical or physical methods to enhance their polarity and thus improve their performance.

[0036] In one embodiment, the air conducting portion of the conductive substrate is respectively connected to the conductive portions at both ends of the conductive substrate.

[0037] In one embodiment, the number of the vent holes is one or more; the number of the vent filling layers is the same as the number of the vent holes. Specifically, each vent hole is equipped with a vent filling layer. It should be noted that the present invention does not limit the arrangement of the plurality of vent holes, and those skilled in the art can set it according to actual needs.

[0038] In one embodiment, the shape of the ventilation hole may be a quadrilateral or a dumbbell shape, or may be other shapes, which is not limited in the present invention.

[0039] In one embodiment, if Figure 1 As shown, a positioning and limiting groove 111 is provided at the boundary of the breathable through hole 11 so as to keep the breathable filling layer 2 and the breathable through hole 11 in a fixed position.

[0040] In one embodiment, there may be multiple positioning and limiting grooves disposed at the boundary of each vent hole. The present invention does not limit the specific number of positioning and limiting grooves.

[0041] In one embodiment, the shapes of the positioning and limiting grooves include but are not limited to sawtooth, quadrilateral, T-shape, etc.

[0042] In one embodiment, if Figures 1 to 4 As shown, the breathable filling layer is also used to support the gas-conducting adhesive film, so that the gas-conducting adhesive film has higher strength and will not be deformed due to high air pressure; the breathable filling layer can also isolate the penetration of external moisture of the soft-pack battery cell.

[0043] In a specific embodiment, the breathable filling layer adopts a breathable and water-absorbent supporting sheet.

[0044] In one embodiment, the breathable filling layer is composited by a water-absorbent material and a foam substrate; wherein the water-absorbent material is at least one of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, microcrystalline cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and ethyl cellulose; and the substrate is at least one of polyurethane foam, polystyrene foam and foam glass.

[0045] In a specific embodiment, the breathable filling layer can be composited from carboxymethyl cellulose (CMC) reinforced fiber material and polyurethane (PU) foam material. This breathable filling layer combines the water absorption of CMC with the structural strength and elasticity of PU foam, and has both water absorption, air permeability and strength.

[0046] Specifically, the process of composite carboxymethyl cellulose (CMC) reinforced fiber material and polyurethane (PU) foam material includes:

[0047] The first step is raw material preparation:

[0048] (1) Preparation of carboxymethyl cellulose (CMC) reinforced fiber material: CMC powder is dissolved in water to prepare a CMC solution, and the concentration of the prepared CMC solution is 0.5% to 3%; a reinforcing agent (such as a cross-linking agent) is introduced into the prepared CMC solution to improve the strength and water resistance of the fiber.

[0049] (2) Polyurethane (PU) foam material: Select open-cell polyurethane foam to meet the water absorption requirements and ensure that the polyurethane foam has uniform thickness and a clean and pollution-free surface.

[0050] The second step is preprocessing:

[0051] (1) Pretreatment of polyurethane (PU) foam material: The polyurethane (PU) foam is cleaned and dried to remove oil and impurities on the foam surface, and then the foam surface is activated using plasma or chemical reagents (such as) silane coupling agents to improve the adhesion between CMC and the foam.

[0052] (2) Preparation of CMC solution: Add appropriate amount of thickener and cross-linking agent (such as glutaraldehyde or boric acid) to the CMC solution to enhance the stability of the CMC layer after coating.

[0053] Step 3, coating or impregnation:

[0054] The coating process includes: using coating equipment (such as roller coating equipment, blade coating equipment) to uniformly coat the CMC solution on one or both sides of the PU foam; wherein the coating thickness can be adjusted by adjusting the concentration of the CMC solution and the coating equipment parameters.

[0055] The impregnation process includes: immersing the PU foam in the CMC solution so that the surface and some pores of the PU foam fully absorb the CMC solution; squeezing the PU foam to remove excess solution to ensure uniform thickness.

[0056] Step 4: Drying and cross-linking:

[0057] Cross-linking treatment includes: after coating or impregnation, the cross-linking of CMC is completed by heating or chemical methods to enhance water resistance and adhesion strength. The cross-linking of CMC refers to the formation of cross-linking bonds between CMC molecules through chemical or physical methods, thereby constructing a polymer compound with a three-dimensional network structure.

[0058] The drying process includes: drying the PU foam coated with CMC or impregnated with CMC in an oven at 50°C to 80°C after the cross-linking treatment to ensure that the CMC layer is completely cured without affecting the elasticity of the PU foam; wherein the specific temperature and drying time of the oven can be adjusted according to the characteristics of the CMC and the thickness of the PU foam.

[0059] Step 5: Post-processing and composite reinforcement: If higher strength is required, a thin layer of non-woven fabric or fiber mesh can be superimposed on the surface of the cured CMC layer for reinforcement; the non-woven fabric or fiber mesh can be fixed by hot pressing or gluing.

[0060] Multiple PU foams with cured CMC layers are stacked and pressed into thick sheets to improve structural strength and water absorption performance.

[0061] Step 6: Cutting and forming:

[0062] The thick sheet is cut into sheets or rolls according to the shape of the ventilation holes, and the dimensional accuracy is guaranteed.

[0063] In one embodiment, if Figures 1 to 3 As shown, the air-conducting film 3 extends to both sides of the conductive substrate 1 to form a film extension portion. The film extension portion plays a role in fixing the air-permeable tab and preventing a short circuit between the conductive substrate and the aluminum-plastic film.

[0064] In one embodiment, the number of layers of the air-conducting adhesive film is at least two.

[0065] When the number of layers of the air-conducting adhesive film is two, the air-conducting adhesive film is composed of an outer layer and an inner layer; wherein the inner layer is coated on the periphery of the air-conducting portion; and the outer layer is coated on the outer surface of the inner layer;

[0066] The inner layer is made of modified polypropylene, polyacrylic acid, and polyethylene copolymers containing polar groups; the polar groups include but are not limited to carbonyl, amino, and hydroxyl groups; the outer layer is a polymer film composited with modified polypropylene, polyacrylic acid, and polyolefin elastomer.

[0067] It should be noted that copolymerization is a method of synthesizing polymer materials, which involves the co-polymerization of two or more monomers to generate polymers containing these monomer units. Composite refers to the combination of two or more materials with different properties through physical or chemical methods to form a material with new properties on a macro scale.

[0068] In one embodiment, the air-permeable filling layer may also be made of fine-pored silica gel. Specifically, the air-permeable water-absorbent support sheet is obtained by laminating the fine-pored silica gel.

[0069] Similar to the above embodiment, the present invention also provides a soft-pack battery. The soft-pack battery is provided with the above-mentioned ventilated tab; the ventilated tab leads the electrode of the soft-pack battery out of the soft-pack battery; Figure 4 As shown, the aluminum-plastic film 4 of the soft-pack battery is used to seal the gas-conducting adhesive film 3 and the corresponding gas-conducting portion, and the upper and lower sealing seams formed by the aluminum-plastic film 4 and the upper and lower layers of the gas-conducting adhesive film are located at the upper and lower sides of the air-permeable through hole.

[0070] Specifically, the aluminum-plastic film top seal of the soft-pack battery refers to encapsulating the positive and negative electrodes of the soft-pack battery together through the aluminum-plastic film material and sealing them in the packaging material to form a top packaging structure. The aluminum-plastic film 4 and the upper layer of the gas-conducting adhesive film 3 form an upper sealing seam, and the upper sealing seam is located on the upper side of the air-permeable through hole 11; the aluminum-plastic film 4 and the lower layer of the gas-conducting adhesive film 3 form a lower sealing seam, and the lower sealing seam is located on the lower side of the air-permeable through hole 11.

[0071] In a specific embodiment, if Figure 4 As shown, the gas generated in the soft-pack battery enters the breathable filling layer 2 through the gas-conducting adhesive film 3, moves in the breathable filling layer 2 to the outside of the joint between the aluminum-plastic film 4 and the gas-conducting adhesive film, and then passes through the gas-conducting adhesive film 3, and is discharged from the outside of the soft-pack battery.

[0072] It should be noted that the direction of gas discharge can refer to Figure 4 The outer side of the joint between the aluminum-plastic film 4 and the gas-conducting adhesive film is the side connected to the outside of the battery.

[0073] It should also be noted that the attached Figures 1 to 4 A gas-permeable tab with one gas-permeable through hole is shown. The gas exhaust path of the gas-permeable tab with multiple gas-permeable through holes is similar to the gas exhaust path of the gas-permeable tab with one gas-permeable through hole.

[0074] It should be understood that the tabs in the prior art (see Figure 5 ) The gas discharge path is the path indicated by arrow A. The length of the discharge path is the width of the ear glue, and the width of the ear glue is generally more than 5mm, so it has no air permeability. The length of the gas discharge path of the present invention is twice the thickness of the gas-conducting adhesive film, and the thickness of the gas-conducting adhesive film is generally several hundred microns, and the air permeability is better. Therefore, when the gas pressure generated by the ear of the present invention inside the soft-pack battery reaches a certain value, it can be discharged to the outside of the soft-pack battery through the ear, which plays a role in purifying the internal atmosphere of the battery cell.

[0075] Figure 6 Schematic diagram of the process for preparing the breathable tab provided in the embodiment of the present application. Figure 6 As shown, the preparation method of the breathable tab includes:

[0076] Step S61: providing a conductive substrate; wherein the conductive substrate includes conductive portions disposed at both ends and an air-conducting portion disposed in the middle;

[0077] Step S62: forming a ventilation hole on the air-conducting portion of the conductive substrate;

[0078] Step S63: providing a breathable filling layer in the breathable through hole;

[0079] Step S64: using an air-conducting adhesive film to cover the periphery of the air-conducting portion and seal the air-permeable through hole.

[0080] It should be understood that the specific implementation process of each step has been described in detail in the above embodiments, and for the sake of brevity, it will not be repeated here.

[0081] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0082] In summary, the present application provides a breathable pole ear, a method for preparing a breathable pole ear, and a soft-pack battery. The breathable pole ear includes a conductive substrate, the conductive substrate includes a conductive portion arranged at both ends and a gas-conducting portion arranged in the middle, a breathable through hole is formed on the gas-conducting portion, and a breathable filling layer is arranged in the gas-conducting through hole; the gas-conducting adhesive film is coated on the periphery of the gas-conducting portion and covers the gas-conducting through hole. The breathable pole ear of the present application allows the gas in the soft-pack battery to be discharged to the outside of the soft-pack battery in a unidirectional manner, which plays a role in purifying the atmosphere inside the soft-pack battery cell. Therefore, the present application effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0083] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A breathable tab, characterized in that: include: A conductive substrate, the conductive substrate comprising conductive parts arranged at both ends and an air guide part arranged in the middle, and the air guide part is formed with air-permeable through holes; A breathable filling layer, wherein the breathable filling layer is arranged in the breathable through hole; An air-conducting adhesive film is coated on the periphery of the air-conducting portion and covers the air-permeable through hole.

2. The breathable tab according to claim 1, characterized in that: The conductive substrate is made of metal material.

3. The breathable tab according to claim 1, characterized in that: The number of the breathable through holes is one or more; the number of the breathable filling layers is the same as the number of the breathable through holes.

4. The breathable tab according to claim 3, characterized in that: The boundary of the ventilation hole is provided with a positioning and limiting groove so that the ventilation filling layer and the ventilation hole can be kept in a fixed position.

5. The breathable tab according to claim 1, characterized in that: The number of layers of the air-conducting adhesive film is at least two.

6. The breathable tab according to claim 5, characterized in that: When the number of layers of the air-conducting adhesive film is two, the air-conducting adhesive film is composed of an outer layer and an inner layer; wherein the inner layer is coated on the periphery of the air-conducting portion; and the outer layer is coated on the outer surface of the inner layer.

7. The breathable tab according to claim 6, characterized in that: The inner layer is made of copolymerized modified polypropylene, polyacrylic acid and polyethylene containing polar groups; the polar groups include carbonyl, amino and hydroxyl groups; the outer layer is a polymer film composited with modified polypropylene, polyacrylic acid and polyolefin elastomer.

8. The breathable tab according to claim 1, characterized in that: The air-permeable filling layer is composited from a water-absorbing material and a foam substrate.

9. A method for preparing a breathable tab, characterized in that: include: Providing a conductive substrate; wherein the conductive substrate comprises conductive parts arranged at both ends and an air guide part arranged in the middle; forming a ventilation hole on the air-conducting portion of the conductive substrate; A breathable filling layer is arranged in the breathable through hole; An air-conducting adhesive film is used to cover the periphery of the air-conducting portion and seal the air-permeable through hole.

10. A soft pack battery, characterized in that: The soft-pack battery is provided with a breathable pole ear as described in any one of claims 1 to 8; the breathable pole ear leads the electrode of the soft-pack battery out of the soft-pack battery; the air-conducting adhesive film and the corresponding air-conducting part are sealed with the aluminum-plastic film of the soft-pack battery, and the upper and lower sealing seams formed by the aluminum-plastic film and the upper and lower layers of the air-conducting adhesive film are located on the upper and lower sides of the breathable through hole.

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