A battery unit

Abstract

The application discloses a battery power supply, which comprises a packaging assembly, a body and a composite film material which is heat sealed with the body, the body is provided with a pole hole through which an electrode lead is arranged, and a sealing glue is arranged between the electrode lead and the pole hole. The composite film material comprises at least one inner film and one outer film, the inner film is made of a low-molecular polymer, and the inner film has a low melting point and can be firmly heat sealed with the body. The application is based on the flexible composite film material, and the battery power supply has corrosion resistance to internal electrolyte and excellent mechanical properties, and is not easily damaged by external extrusion and puncture. The application provides multiple sealing schemes and processing modes for the electrode lead.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery manufacturing components, and more specifically to a packaging assembly specifically suitable for ultra-thin, flexible film battery cells. Background Technology

[0002] Traditional battery clusters are relatively thick, and the assembly method of pre-compressing and forcibly pushing them into the plastic casing results in low production efficiency. In order to ensure battery life and performance, compressive force needs to be provided to the AGM separator of the battery cluster, so it is difficult to reduce the thickness of existing battery clusters.

[0003] The inventors have pioneered a technology for encapsulating lead-acid battery clusters with flexible membrane materials. In order to ensure the pressure on the AGM separator, it is necessary to apply external pressure to the membrane material filled with electrolyte. On the one hand, this places higher demands on the physicochemical properties of the membrane material, which must not only be acid-resistant and corrosion-resistant, but also have a certain mechanical strength. On the other hand, it is necessary to solve the sealing problem between the membrane material and the battery cluster.

[0004] Currently, the engineering plastics used in battery casings often cannot bond with the film on their surface, resulting in low peel strength. Using film materials commonly used in the packaging industry makes it difficult to achieve the desired sealing effect. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a packaging component for battery cells encapsulated with thin, flexible membrane materials that can withstand continuous high voltage, is acid and corrosion resistant, and has excellent mechanical strength.

[0006] Technical solution: In order to achieve the above-mentioned invention objectives, the present invention provides a battery power supply, including an encapsulation assembly for sealing electrode leads, comprising a body and a composite film material thermally sealed to the body, wherein the body is provided with an electrode lead hole through which the electrode lead passes, and a first sealing medium is provided between the electrode lead and the electrode lead hole. The composite membrane material comprises at least an inner membrane and an outer membrane, wherein the inner membrane and the main body are individually selected from any one of polyethylene, polypropylene, and ethylene-propylene copolymer, and the melting point of the inner membrane is lower than that of the outer membrane.

[0007] Specifically, the melting point of the inner membrane is preferably 150-160 °C, and the melting point of the outer membrane is at least 50 °C higher than that of the inner membrane.

[0008] The first sealing medium is selected from any one or more of epoxy sealant, polyurethane sealant, and polyisobutylene sealant, including but not limited to. Motor indicator markers may optionally be added to the first sealing medium. Preferably, two portions of the first sealing medium are prepared, with red and blue pigments added to each, respectively, to indicate the positive and negative terminals of the battery cluster.

[0009] Furthermore, to ensure that the first sealing medium is sufficient to completely seal the gap between the electrode lead-out end and the electrode post hole, a certain amount of adhesive needs to be applied to prevent the first sealing medium from leaking down along the electrode lead-out end while simultaneously curing it rapidly. This necessitates setting a sunken liquid accumulation groove around the outer periphery of the electrode post hole.

[0010] The viscosity and curing properties of the sealant determine the processing time required. Lower viscosity sealant may flow into the current collector through the gaps in the electrode post holes, potentially causing a short circuit. To provide superior heat-sealing performance, a second sealing medium is further provided between the electrode lead and the electrode post hole. This second sealing medium is connected to the body via the first sealing medium. The second sealing medium has an outer contour adapted to the shape of the electrode post hole and an inner opening that is interference-fitted with the electrode lead.

[0011] The first sealing medium has an irregular shape at room temperature or under heating conditions, while the second sealing medium is a component with a certain shape. The electrode orifice can be any combination of one or more shapes, including but not limited to polygons, circles, ellipses, and spindle shapes, and the outer contour of the second sealing medium also has a corresponding shape. As a preferred embodiment, the second sealing medium and the electrode orifice are assembled together by an interference fit.

[0012] In a preferred embodiment of the present invention, the electrode lead-out end is a tab, and the tabs of the current collector, when stacked, have a certain thickness. Correspondingly, the electrode post hole is designed to be rectangular, so the outer contour of the second sealing medium is a corresponding cuboid, and the inner opening allows the tab to pass through. A preferred design for the inner opening is to form two Y-shaped openings, which facilitates the conformal passage of the tab and reduces leakage during sealant injection.

[0013] In another preferred embodiment of the present invention, the electrode lead-out end is fitted with an electrode post on the current collector tab, the electrode post being a metal conductor with a diameter of 1-10 mm. The electrode post hole is designed to be circular or elliptical, thus the outer contour of the second sealing medium is a corresponding shape, and the inner opening has a circular or elliptical opening for the electrode post to pass through.

[0014] The design scheme for the second sealing medium of the present invention includes, but is not limited to, the forms described above. The second sealing medium and the body can be assembled together using, but is not limited to, slot fitting, interference fit, adhesive bonding, hot melt molding, or secondary injection molding, or a combination of these methods. A preferred embodiment is to install the second sealing medium into the electrode hole using an interference fit, which can be supplemented with adhesive to prevent the second sealing medium from falling off, or a limiting mechanism can be designed on the body to prevent falling off. Another preferred embodiment is to use a secondary injection molding process to place the molded second sealing medium into the injection mold of the body, processing it into an integral structure.

[0015] The second sealing medium of this invention is selected from any one or more combinations of ABS, PC / ABS, PVC, SBS, TPE, TPV, PA, and EVA, including but not limited to ABS, PC / ABS, PVC, SBS, TPE, TPV, PA, and EVA. It can be further modified to meet the process requirements of secondary injection molding and can bond firmly to the plastic strip.

[0016] This invention involves heat-sealing the composite membrane material circumferentially on the outer side of the body. Theoretically, when heat-sealing a flexible material onto a three-dimensional structure, the more corners involved in the heat-sealing surface, the greater the risk of weak heat sealing and easy membrane peeling. For a traditional hexahedron, circumferential heat sealing requires the involvement of four corners. This invention further improves the shape of the body to reduce the number of corners involved in heat sealing; specifically, the number of continuous planes where the body and the composite membrane are heat-sealed together does not exceed two.

[0017] In a preferred embodiment of the present invention, the body is elongated, with pointed ends of a certain curvature at both ends along its length. The pointed ends are rounded off from the body, forming a continuous heat-sealing plane. This design reduces the number of corners involved in heat sealing from four to two, simplifying the heat-sealing process while ensuring effective heat sealing.

[0018] Other forms in which the body and the composite film are thermally bonded to each other, not exceeding two continuous planes, include but are not limited to: the cross-section of the body being circular, elliptical, spindle-shaped, or rectangular with smooth transition arcs at both ends.

[0019] To further improve the heat-sealing effect, the side of the body is provided with several horizontal lines. Optionally, the composite film and the body are heat-sealed together at the horizontal lines using the first sealing medium.

[0020] The horizontal stripe design results in an uneven structure on the side of the body, which can create gaps during heat sealing. This is especially problematic for bodies with pointed ends, where the uneven structure at the edges of the pointed ends can cause gaps during heat sealing of the composite film, leading to electrolyte leakage under pressure. To address this, the horizontal stripes extend along the length to both ends of the body, connecting with the vertical stripes formed at the edges of the pointed ends, thus eliminating the uneven structure at the edges.

[0021] Beneficial Effects: The encapsulation component provided by this invention is based on a flexible composite membrane material, which meets the requirements of corrosion resistance to the internal electrolyte and also possesses excellent mechanical properties, making it resistant to damage from external pressure or puncture. The encapsulation body provided by this invention can be firmly bonded to the composite membrane material, and is simultaneously fixed and sealed to the electrode lead-out end through a sealing medium. This invention provides multiple sealing schemes and processing methods for the electrode lead-out end, and proposes a technique for sealing the electrode post using both an elastomer and a sealant. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of Example 1; Figure 2 yes Figure 1 A partially enlarged schematic diagram of the packaging strip from a top-down view; Figure 3 yes Figure 1 A partially enlarged schematic diagram of the packaging strip viewed from below; Figure 4 This is a schematic diagram of the packaging strip in Example 2. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example

[0024] like Figures 1 to 3 As shown, this embodiment provides a battery unit, including an encapsulation assembly, comprising an encapsulation strip 100 made of PP injection molding. A composite film 200 is heat-sealed along the outer periphery of the sidewall of the encapsulation strip. The encapsulation strip 100 has electrode post holes 120 for electrode tabs to pass through. The electrode post holes 120 are rectangular, and a sealing elastomer 140 with an outer contour adapted to the shape of the electrode post hole is provided inside. The sealing elastomer 140 has an inner opening 142 for the electrode tabs to pass through, and the inner opening is shaped as two opposing Y-shaped openings. A recessed surface 144 is formed within the elastomer for holding sealant. This embodiment uses a two-stage injection molding process; after the sealing elastomer 140 is processed, it is added to the encapsulation strip injection mold for a second injection molding.

[0025] Composite membrane material 200 is composed of a CPP inner membrane and a PET outer membrane, or it can be composited by adding an MPP adhesive layer between the inner and outer membranes. The thickness is between 100-200 micrometers, the tensile strength is not less than 100N / 15mm, and the puncture strength is not less than 200N.

[0026] The encapsulation strip 100 has pointed ends 160 at both ends, and the pointed ends 160 have a smooth transition arc surface with the sidewalls of the encapsulation strip 100. Therefore, when the composite film 200 is heat-sealed to the side of the encapsulation strip, only two corners are involved. The composite film provided in this embodiment is folded in half, and the area adjacent to the crease 260 after folding is heat-sealed to form a first sealing edge 220 and a second sealing edge 240. An opening is left opposite the crease 260 for heat-sealing with the encapsulation strip 100. This sealing method of the composite film is particularly suitable for heat-sealing the aforementioned elongated encapsulation body with pointed ends 160. Hollow grooves 112 may also be provided on the encapsulation strip 100 as necessary to reduce the weight of the encapsulation strip 100, and reinforcing ribs 114 may be provided to resist compression from the sides and prevent deformation of the encapsulation strip.

[0027] To further improve the heat-sealing effect, the sealing strip 100 has horizontal ridges 182 on its side, which extend from the side to the edge of the pointed end and connect to the vertical ridges 184 on the edge. Before heat sealing the composite film material, adhesive is applied to the horizontal ridges 182, and then heat-sealed using a heat-sealing device.

[0028] After the composite membrane 200 is heat-sealed with the encapsulation strip 100 and the pole hole 120 is sealed, a closed space is formed between the encapsulation strip 100 and the composite membrane 200. Even if the composite membrane is subjected to a large external compressive force, the heat-sealed and sealed parts will not loosen or peel off. Example

[0029] Based on Example 1, this embodiment changes the pointed ends of the encapsulation strip to blunt ends. The blunt ends have a semi-circular structure, forming a smooth transition with the sidewall of the encapsulation strip. This creates a smooth, continuous heat-sealed surface on the side of the encapsulation strip. Structurally, the absence of folds improves the sealing performance. The film sealing method is also correspondingly improved. The film is not folded; instead, it is heat-sealed along the outer periphery of the encapsulation strip according to a preset length and position, forming a ring of film with the sealing edge located at the center line. The bottom is then heat-sealed last. The advantage of this encapsulation method is that it avoids the first and second sealing edges found in Example 1. After being stored in the battery casing, it does not occupy additional space, making the product more compact. Example

[0030] exist Figure 1 Based on this, please combine Figure 4 As shown, this embodiment provides a packaging assembly with a circular electrode post hole. The materials of the package body 300 and the flexible film are the same as in Embodiment 1. The electrode post hole 320 is circular, which is more conducive to assembly with busbars or cables compared to flat and elongated electrode tabs. Correspondingly, the electrode tab needs to be connected to the electrode post first and then led out from the electrode post hole 320.

[0031] At this point, the elastomer 340 is also designed with a cylindrical outer contour. The outer diameter of the elastomer 340 can be slightly larger than the diameter of the electrode post hole 320, allowing it to be assembled into the electrode post hole 320 with an interference fit. The inner opening 342 of the elastomer 340 is circular, and its diameter can also be designed to be slightly smaller than the outer diameter of the electrode post, allowing the electrode post to pass through the inner opening 342 with an interference fit, thus improving sealing. If an interference fit design is not used, the elastomer 340 can be coated with sealant and then filled into the electrode post hole 320. The sidewall of the elastomer 340 is designed as a thin wall 344, meaning that the outer diameter of the elastomer is larger than its inner diameter, which is larger than the inner opening diameter. When the electrode post passes through the inner opening 342, a gap is still left between it and the thin wall 344 of the elastomer 340, allowing for the injection of sealant to cure and form a compact integral structure, preventing sealant leakage during processing.

[0032] A constriction 322 is formed within the terminal hole 320 of the encapsulation strip 300, which serves to limit the elastomer 340. The distance from the constriction 322 to the upper surface of the encapsulation strip is greater than the height of the elastomer 340. Therefore, after the elastomer 340 is assembled into the terminal hole 320, the upper edge of the elastomer 340 remains lower than the upper surface of the encapsulation strip 200. This design also facilitates the addition and curing of sealant. Alternatively, a recessed groove can be formed around the terminal hole, which also helps to provide sufficient sealant and improve sealing performance.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A battery cell, comprising an encapsulation assembly for sealing electrode leads, characterized in that: The encapsulation assembly includes a body and a composite film material thermally bonded to the body. The body is provided with an electrode lead hole through which an electrode lead-out end passes, and a first sealing medium is provided between the electrode lead-out end and the electrode lead hole. The composite membrane material includes at least one inner membrane and one outer membrane. The inner membrane and the main body are individually selected from any one of polyethylene, polypropylene, and ethylene-propylene copolymer. The melting point of the inner membrane is lower than that of the outer membrane. The melting point of the inner membrane is 150-160°C, and the melting point of the outer membrane is at least 50°C higher than that of the inner membrane. The body surface and the outer periphery of the pole hole are provided with a liquid accumulation groove; A second sealing medium is provided between the electrode lead-out end and the electrode post hole. The second sealing medium is connected to the body through the first sealing medium. The second sealing medium has an outer contour that matches the shape of the electrode post hole and an inner opening that is interference-fitted with the electrode lead-out end. The body is elongated, with pointed ends with a certain curvature at both ends along its length. The pointed ends and the body are connected by rounded corners to form a continuous heat-sealing plane. The side of the body has several horizontal lines along its length, which extend to both ends of the body and connect with the vertical lines formed at the edges of the pointed ends.

2. A battery unit according to claim 1, characterized in that: The first sealing medium includes any one or more of epoxy sealant, polyurethane sealant, and polyisobutylene sealant.

3. A battery unit according to claim 1, characterized in that: The pole hole can be any one or more of the following shapes: polygonal, circular, elliptical, or spindle-shaped.

4. A battery unit according to claim 3, characterized in that: The electrode lead-out end is a tab, and the electrode post hole is rectangular with a Y-shaped opening inside.

5. A battery unit according to claim 3, characterized in that: The electrode lead-out end is an electrode post, and the electrode post hole is circular or elliptical, with a circular or elliptical opening inside.

6. A battery unit according to claim 4 or 5, characterized in that: The second sealing medium is installed in the electrode hole by interference fit, or is processed into an integral structure with the body by secondary injection molding.

7. A battery unit according to claim 6, characterized in that: The second sealing medium is selected from any one of ABS, PC / ABS, PVC, SBS, TPE, TPV, PA, and EVA.

8. A battery unit according to any one of claims 1-5 or 7, characterized in that: The number of continuous planes in which the body and the composite film are thermally bonded together does not exceed two.

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