Aluminum plastic film structure, battery cell and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to an aluminum-plastic film structure, a battery cell and a battery. The aluminum plastic film structure comprises a containing part and an edge sealing part connected to the containing part. A placing cavity is formed in the accommodating part; a buffer cavity is formed in the edge sealing part; the buffer cavity is communicated with the placing cavity; the edge sealing component comprises an inner connecting area and a sealing area which face the edge sealing component from the containing component. An inclined section and a guide section which are connected in sequence are arranged in the inner connecting area; and the inclined section is connected to the accommodating part. According to the utility model, the electrolyte can be quickly transferred to the air bag, and the seal impact on the top seal is reduced; and the safety and the stability of formation processing are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and in particular relates to an aluminum-plastic film structure, a battery core and a battery. Background Art

[0002] Lithium-ion batteries have attracted considerable attention due to their high energy density and excellent safety performance. As their application in consumer electronics becomes increasingly mature, they are gradually transitioning to new energy vehicles. Soft-pack batteries are a key component of lithium-ion batteries, consisting of an aluminum-plastic film and a battery cell. Conventional aluminum-plastic film includes side and top seals, which are heat-sealed and fused together using a sealing head during packaging.

[0003] However, the main reason for lithium-ion battery cells to experience top seal puncture is that the battery body is squeezed during the formation process, causing the gas and liquid inside the battery body to diffuse outward. When the pressure at the top seal of the battery cell exceeds the pressure of the aluminum-plastic film sol, the top seal puncture will occur, which will cause corrosion of the aluminum-plastic film and eventually lead to battery failure, affecting its safety and stability. Utility Model Content

[0004] The purpose of the utility model is to provide an aluminum-plastic film structure to solve the technical problems of poor safety and stability in existing technology.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] An aluminum-plastic film structure comprises a containing component and an edge-sealing component connected to the containing component; a placement cavity is provided in the containing component; a buffer cavity is provided in the edge-sealing component; the buffer cavity is communicated with the placement cavity; and the edge-sealing component comprises an inner connecting area and a sealing area extending from the containing component toward the edge-sealing component; an inclined section and a guide section connected in sequence are provided in the inner connecting area; the inclined section is connected to the containing component.

[0007] Preferably, the inclined section is arranged to be inclined outward from the placement cavity toward the buffer cavity.

[0008] Preferably, an angle α is provided between the vertical surface where the inclined section is located and the inclined section; and the angle α satisfies: 5°≤α≤15°.

[0009] Preferably, the guide section is arranged to be concave inwardly in an arc shape from the outside of the edge sealing component toward the buffer cavity.

[0010] Preferably, the radius d of the circle where the arc-shaped concave cross-section of the guide segment lies satisfies: 0.6 mm ≤ d ≤ 0.9 mm.

[0011] Preferably, an arc-shaped connecting section is provided between the accommodating component and the edge-sealing component; the arc-shaped connecting section is provided to protrude in an arc shape from the buffer cavity toward the outside of the accommodating component.

[0012] Preferably, the edge sealing component further includes an outer connecting area; the outer connecting area and the inner connecting area are arranged opposite to the sealing area.

[0013] Preferably, the relationship among the width L1 of the sealing area, the width L2 of the inner connecting area and the width L3 of the outer connecting area satisfies: 1.1 mm ≤ L1 + L2 + L3 ≤ 1.3 mm.

[0014] The utility model also discloses a battery cell, comprising a battery cell body and the above-mentioned aluminum-plastic film structure; the battery cell body is connected to the placement cavity; and the battery cell body comprises a first pole ear and a second pole ear, and a first pole piece, an isolation film and a second pole piece arranged in sequence; and the first pole piece is connected to one end of the first pole ear; the other end of the first pole ear is arranged through the aluminum-plastic film structure; the second pole piece is connected to one end of the second pole ear; the other end of the second pole ear is arranged through the aluminum-plastic film structure.

[0015] The utility model also discloses a battery, comprising the battery core.

[0016] The beneficial effect of the present invention is that the technical solution stores electrolyte and bare battery cells by placing a cavity, and the inclined section of the internal connection area can effectively increase the internal cross-sectional area, so that the internal gas and liquid diffused to the surroundings due to the extrusion stress can be effectively accommodated, and the guide section can increase the accommodation speed and buffer the stress of the diffusion impact, thereby accelerating the rapid transfer of the electrolyte to the air bag and reducing the impact on the top seal; and increasing the liquid retention capacity of the battery cell, which is beneficial to extending the cycle life of the battery cell; at the same time, improving the safety and stability of the chemical processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following will refer to the attached Figures 1 to 4 To describe the features, advantages and technical effects of exemplary embodiments of the present invention.

[0018] Figure 1 This is a structural diagram of an aluminum-plastic film structure according to an embodiment of the present invention;

[0019] Figure 2 This is a partial enlarged view of the aluminum-plastic film structure of an embodiment of the present utility model;

[0020] Figure 3 This is a schematic structural diagram of the aluminum-plastic film structure of one embodiment of the present utility model when in use;

[0021] Figure 4 This is a schematic structural diagram of a battery cell according to an embodiment of the present invention.

[0022] In the figure: O-center of circle; 1-containing component; 11-first sub-body; 12-second sub-body; 110-edge sealing component; 101-inner connection area; 102-sealing area; 103-outer connection area; 104-buffer cavity; 105-arc-shaped connecting section; 106-placing cavity; 107-channel; 2-inclined section; 3-guide section; 5-cell body; 51-isolating membrane; 52-first pole piece; 53-second pole piece; 54-ear body; 541-first pole ear; 542-second pole ear. DETAILED DESCRIPTION

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0024] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or multiple situations exist. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0027] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0028] The following is combined with Figures 1 to 4 The present invention is further described in detail, but is not intended to limit the present invention.

[0029] like Figure 1 As shown, in one embodiment of the present invention, the aluminum-plastic film structure includes a container 1 and an edge-sealing component 110 connected to the container 1. The container 1 is provided with a placement cavity 106. The edge-sealing component 110 is provided with a buffer cavity 104. The buffer cavity 104 is connected to the placement cavity 106. The edge-sealing component 110 includes an inner connecting area 101 and a sealing area 102 extending from the container 1 toward the edge-sealing component 110. The inner connecting area 101 is provided with an inclined section 2 and a guide section 3 connected in sequence. The inclined section 2 is connected to the container 1. The container 1 and the edge-sealing component 110 are integrally fixed.

[0030] The technical solution of the present invention stores electrolyte and bare battery cells by placing a cavity, and the inclined section of the internal connection area can effectively increase the internal cross-sectional area, so as to effectively accommodate the internal gas and liquid that diffuses to the surroundings due to the extrusion stress, and the guide section can increase the storage speed and buffer the stress of the diffusion impact, thereby accelerating the rapid transfer of the electrolyte to the air bag and reducing the impact on the top seal; and increasing the liquid retention capacity of the battery cell, which is beneficial to extending the cycle life of the battery cell; at the same time, improving the safety and stability of the chemical processing.

[0031] Specifically, in some embodiments, Figure 1 As shown, the edge sealing member 110 further includes an external connection area 103, which is positioned opposite the internal connection area 101 within the sealing area 102 and is used to connect to the airbag. In other words, the internal connection area 101, by containing and guiding the internal electrolyte and gas, effectively accelerates the transfer of electrolyte to the airbag, reduces the impact on the top seal, and thus improves the top seal.

[0032] Specifically, in some embodiments, Figure 1As shown, the edge sealing member 110 is provided with a channel 107, which respectively passes through the inner connection area 101, the sealing area 102, and the outer connection area 103. This structure can ensure the smooth flow of electrolyte and gas, and ensure the convenience of tab installation.

[0033] Wherein, in some embodiments, Figure 1 and 2 As shown, the aluminum-plastic film structure includes a first sub-body 11 and a second sub-body 12 arranged side by side; the entirety formed by the container 1 and the edge-sealing component 110 is the first sub-body 11 and / or the second sub-body 12. In other words, the upper half formed by the container 1 and the edge-sealing component 110 is the first sub-body 11, and the lower half formed by the container 1 and the edge-sealing component 110 is the second sub-body 12.

[0034] Specifically, in some embodiments, Figure 1 As shown, the relationship among the width L1 of the sealing area 102, the width L2 of the inner connection area 101 and the width L3 of the outer connection area 103 satisfies: 1.1 mm ≤ L1 + L2 + L3 ≤ 1.3 mm.

[0035] Specifically, in some embodiments, Figure 1 and 3 As shown, an arcuate connecting section 105 is provided between the receiving component 1 and the edge sealing component 110; the arcuate connecting section 105 is arranged to protrude in an arc shape from the buffer cavity 104 toward the outside of the receiving component 1. In other words, the outwardly protruding arcuate connecting section 105 can further increase the overall cross-sectional area to a certain extent, thereby accelerating the rapid transfer of electrolyte to the air bag, thereby reducing the impact on the top seal and improving the top seal.

[0036] Specifically, in some embodiments, Figure 1 and 3 As shown, the inclined section 2 is tilted outward from the placement cavity 106 toward the buffer cavity 104. An included angle α is formed between the vertical surface on which the inclined section 2 is located and the inclined section 2, and the included angle α satisfies the following conditions: 5°≤α≤15°. This structure, through the included angle α of 5° to 15° and the guide section 3, can accelerate the transfer of electrolyte to the air bag, reduce the impact on the top seal, reduce the pressure on the top seal edge, and reduce the possibility of poor sealing. This in turn increases the electrolyte retention in the battery cell, which helps extend the cycle life of the battery cell. It also improves the safety and stability of the formation process.

[0037] Specifically, in some embodiments, Figure 1 and 3As shown, the guide section 3 is provided with an arc-shaped depression inward from the outside of the edge sealing component 110 toward the direction of the buffer cavity 104. The radius d of the circle where the arc-shaped depression section of the guide section 3 is located satisfies the following conditions: 0.6mm≤d≤0.9mm. In other words, the inclined section 2 with an angle α of 5° to 15° combined with the guide section 3 with a radius d of 0.6mm to 0.9mm can increase the cross-sectional area of ​​the seal, thereby accelerating the rapid transfer of the electrolyte to the air bag, reducing the impact on the top seal, reducing the pressure on the top seal, and reducing the possibility of poor punching and sealing; thereby increasing the liquid retention of the battery cell, which is beneficial to extending the cycle life of the battery cell; and at the same time improving the safety and stability of the chemical processing.

[0038] The present invention also provides a battery cell, such as Figure 3 and 4 As shown, the battery cell includes a battery cell body 5 and an aluminum-plastic film structure; the battery cell body 5 is connected to the placement cavity 106; and the battery cell body 5 includes a tab body 54 and a first pole piece 52, a separator 51, and a second pole piece 53 arranged in sequence; the tab body 54 includes a first pole piece 541 and a second pole piece 542; the first pole piece 52 is connected to one end of the first pole piece 541; the other end of the first pole piece 541 is disposed through the channel 107; the second pole piece 53 is connected to one end of the second pole piece 542; the other end of the second pole piece 542 is disposed through the channel 107. The specific structure of the aluminum-plastic film structure refers to the above embodiments. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0039] Example 1

[0040] 1. Preparation of the battery cell body 5 (bare battery cell):

[0041] (1) Positive electrode preparation: lithium cobalt oxide, conductive agent superconducting carbon (Super-P), and binder polyvinylidene fluoride (PVDF) are mixed evenly in a mass ratio of 97:1.5:1.5 to prepare a lithium-ion battery positive electrode slurry with a certain viscosity. The slurry is coated on the current collector aluminum foil, dried at 85°C, and then cold pressed and stripped;

[0042] (2) Preparation of negative electrode: Graphite, conductive agent superconducting carbon (Super-P), thickener CMC, and binder (SBR) are mixed evenly in a mass ratio of 97:0.3:1.2:1.5 to form a lithium-ion battery negative electrode slurry with a certain viscosity. The slurry is coated on the current collector copper foil, dried at 85°C, and then cold pressed and stripped;

[0043] (3) Isolation film: PE base film is coated with aluminum oxide / PVDF slurry on both sides, dried, and cut into strips for later use;

[0044] (4) Winding the positive electrode sheet and the negative electrode sheet through the isolation film into a bare battery cell (battery cell body 5);

[0045] 2. Production of aluminum-plastic film structure and battery body 5 (bare battery):

[0046] (1) Taking the 2695B1 size structure battery cell as an example: DNP 91 aluminum-plastic film structure is used for stamping. When the aluminum-plastic film structure is stamped into the die shell, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 10°, and the radius d corresponding to the R angle of the guide section 3 in the edge sealing component 110 is controlled at 0.8 mm;

[0047] (2) The prepared aluminum-plastic film structure is packaged with the battery body 5 (bare battery), and the width (L1+L2+L3) of the top seal (edge ​​sealing component 110) is 1.2±0.1 mm (specifically 1 mm);

[0048] (3) The encapsulated cell body 5 (bare cell) is baked at 80±5°C (specifically 80°C) and vacuum ≤-97KPa (specifically -97KPa) for 8 to 15 hours (specifically 12 hours); ensuring that the water content of the cell is ≤150ppm (specifically 100ppm) before liquid injection;

[0049] (4) Fill the battery cell with liquid and let it stand at room temperature for 24 hours or at high temperature for 16 hours before it is ready for use.

[0050] Seal test:

[0051] A forming cabinet is used, the surface pressure of the battery cell is 1.0 MPa, the speed of the forming fixture to tighten the battery cell is 10 mm / s, the temperature of the forming fixture is 80±5°C (specifically 80°C), and the battery cell is charged to 70% SOC; the corresponding battery cell punching and sealing ratio is obtained.

[0052] Example 2

[0053] The difference between Example 2 and Example 1 is that the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled to be 0.6 mm.

[0054] Example 3

[0055] The difference between Example 3 and Example 1 is that the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled to be 0.9 mm.

[0056] Example 4

[0057] The difference between Example 4 and Example 1 is that when the aluminum-plastic film structure is used to punch the mold shell, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 5°.

[0058] Example 5

[0059] The difference between Example 5 and Example 1 is that when the aluminum-plastic film structure is used to punch the mold shell, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 15°.

[0060] Comparative Example 1

[0061] The difference between Comparative Example 1 and Example 1 is that when the aluminum-plastic film structure is used to punch the mold shell, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 0°; the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled at 0.6 mm.

[0062] Comparative Example 2

[0063] The difference between Comparative Example 2 and Example 1 is that when the aluminum-plastic film structure is used to punch the mold shell, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 3°.

[0064] Comparative Example 3

[0065] The difference between Comparative Example 3 and Example 1 is that the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled to be 0.5 mm.

[0066] Comparative Example 4

[0067] The difference between Comparative Example 4 and Example 1 is that the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled to be 1.0 mm.

[0068] Comparative Example 5

[0069] The difference between Comparative Example 5 and Example 1 is that the radius d corresponding to the circle of the R angle of the guide section 3 in the edge sealing component 110 is controlled to be 0 mm.

[0070] Table 1 Performance parameters of all embodiments and comparative examples

[0071]

[0072]

[0073] Result analysis:

[0074] During the formation process, when the battery cell body is subjected to force, the angle α between the inclined section 2 in the edge sealing component 110 and the vertical direction is 5° to 15° when the aluminum-plastic film structure is punching the mold shell. The radius d corresponding to the circle of the R angle of the guide section 3 in the corresponding edge sealing component 110 is controlled to be 0.6 to 0.9 mm (when the radius d is too large, the gas flow rate will be excessive and cause impact damage; when the radius d is too small, the guiding effect will be poor and the top sealing edge will be impacted), so as to perform a diversion effect; thereby, the cross-sectional area of ​​the top seal is increased, and the single flow of liquid and gas-liquid at the corresponding top seal position is increased, which can be quickly guided into the air bag, reducing the impact on the top sealing edge, so as to improve the top seal, so that the punching seal ratio is further reduced.

[0075] The first electrode sheet 52 can be a positive electrode sheet, and the second electrode sheet 53 can be a negative electrode sheet; alternatively, the first electrode sheet 52 can be a negative electrode sheet, and the second electrode sheet 53 can be a positive electrode sheet. Furthermore, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, which is coated on the surface of the positive electrode current collector. The positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes a positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, which is coated on the surface of the negative electrode current collector. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon. The separator 51 can be made of PP (polypropylene) or PE (polyethylene).

[0076] The present invention also provides a battery, which includes a battery cell. The specific structure of the battery cell refers to the above embodiments. Since the battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0077] A battery refers to a cup, tank, or other container, or a portion of a composite container, that contains an electrolyte solution and metal electrodes to generate an electric current. It is a device capable of converting chemical energy into electrical energy. Batteries have positive and negative electrodes. With technological advancements, batteries have become a general term for small devices that can generate electrical energy, such as solar cells. Key battery performance parameters include electromotive force, capacity, specific energy, and resistance. Battery Principle: In chemical batteries, the direct conversion of chemical energy into electrical energy occurs through spontaneous chemical reactions within the battery, such as oxidation and reduction, which occur at the two electrodes. The negative electrode active material consists of a reducing agent with a relatively negative potential and is stable in the electrolyte, such as active metals like zinc, cadmium, and lead, and hydrogen or hydrocarbons. The positive electrode active material consists of an oxidizing agent with a relatively positive potential and is stable in the electrolyte, such as metal oxides like manganese dioxide, lead dioxide, and nickel oxide, oxygen or air, halogens and their salts, and oxygen-containing acids and their salts. The electrolyte is a material with good ionic conductivity, such as aqueous solutions of acids, bases, and salts, organic or inorganic non-aqueous solutions, molten salts, or solid electrolytes.

[0078] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0079] Based on the disclosure and teachings of the above description, those skilled in the art will be able to make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention fall within the scope of protection of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation on the present invention.

Claims

1. An aluminum-plastic film structure, characterized in that: It includes a accommodating component and an edge sealing component connected to the accommodating component; a placement cavity is provided in the accommodating component; a buffer cavity is provided in the edge sealing component; the buffer cavity is communicated with the placement cavity; and the edge sealing component includes an inner connecting area and a sealing area from the accommodating component toward the edge sealing component; an inclined section and a guide section connected in sequence are provided in the inner connecting area; the inclined section is connected to the accommodating component.

2. The aluminum-plastic film structure according to claim 1, characterized in that: The inclined section is arranged to be inclined outward from the placement cavity toward the buffer cavity.

3. The aluminum-plastic film structure according to claim 2, characterized in that: An included angle α is provided between the vertical surface where the inclined section is located and the inclined section; and the included angle α satisfies: 5°≤α≤15°.

4. The aluminum-plastic film structure according to claim 1, 2 or 3, characterized in that: The guide section is arranged to be concave inwardly in an arc shape from the outside of the edge sealing component toward the buffer cavity.

5. The aluminum-plastic film structure according to claim 4, characterized in that: The radius d of the circle where the arc-shaped concave cross-section of the guide segment lies satisfies the following: 0.6 mm ≤ d ≤ 0.9 mm.

6. The aluminum-plastic film structure according to claim 1, characterized in that: An arc-shaped connecting section is provided between the accommodating component and the edge-sealing component; the arc-shaped connecting section is provided in an arc-shaped protrusion from the buffer cavity toward the outside of the accommodating component.

7. The aluminum-plastic film structure according to claim 1, characterized in that: The edge sealing component further includes an outer connecting area; the outer connecting area and the inner connecting area are arranged opposite to the sealing area.

8. The aluminum-plastic film structure according to claim 7, characterized in that: The relationship between the width L1 of the sealing area, the width L2 of the inner connecting area, and the width L3 of the outer connecting area satisfies the following equation: 1.1 mm ≤ L1 + L2 + L3 ≤ 1.3 mm.

9. A battery cell, characterized in that: It comprises a battery cell body and the aluminum-plastic film structure according to any one of claims 1 to 8 above; the battery cell body is connected to the placement cavity; and the battery cell body comprises a first pole tab and a second pole tab and a first pole piece, an isolation film and a second pole piece arranged in sequence; and the first pole piece is connected to one end of the first pole tab; the other end of the first pole tab is arranged through the aluminum-plastic film structure; the second pole piece is connected to one end of the second pole tab; the other end of the second pole tab is arranged through the aluminum-plastic film structure.

10. A battery, characterized in that: Including the battery cell according to claim 9.

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