A Mylar membrane structure and a battery

Abstract

This utility model discloses a Mylar film structure and a battery. The Mylar film structure includes: a film body for wrapping a battery cell; at least one covering strip, one end of which is connected to the film body, and the other end of which extends outward to form a connecting portion; and at least one protective sheet fixedly disposed on the covering strip, located near the end of the battery cell. By applying this utility model, a Mylar film structure and a corresponding battery suitable for encapsulating and protecting battery cells are provided. The flexible film body forms an overall wrapping of the battery cell, and the covering strip connected to the film body restrains the ends of the battery cell. Simultaneously, the protective sheet provides rigid protection for the battery cell, thereby improving the battery's safety and reliability. Furthermore, the entire Mylar film structure exhibits strong stability and high assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing technology, and in particular to a Mylar membrane structure and a battery. Background Technology

[0002] Currently, the manufacturing process of lithium-ion batteries often involves encapsulating and protecting the battery cells with Mylar film, and then assembling them into the battery casing after encapsulation. Therefore, as a core component for encapsulating and protecting the battery cells, the design of the Mylar film structure and the reliability of the encapsulation process directly determine the battery's safety and cycle life. In existing technologies, Mylar films typically employ a simple wrapping configuration and are fixed to the lower plastic or top cover using a hot-melt bonding process.

[0003] However, in traditional hot-melt processes, the precision of coordinated control of temperature, pressure, and time parameters is often insufficient, easily leading to over-melting or poor bonding of the membrane. In the over-melting state, localized thermal deformation or even fiberization of the Mylar membrane can cause poor weld penetration around the edges; while poor bonding results in insufficient membrane adhesion strength, causing it to detach during battery charging and discharging expansion, leading to electrode exposure and electrolyte leakage, seriously threatening battery safety. Furthermore, traditional Mylar membranes have weak three-dimensional constraint on the battery cell, leading to cell delamination. This phenomenon not only exacerbates internal resistance and capacity decay but can also cause internal short circuits due to electrode wrinkles, significantly reducing battery energy density retention and cycle life.

[0004] Furthermore, during the assembly of square battery modules, the locking pressure applied by the retaining frame to the cell is concentrated on the edge area of ​​the electrode. The coating structure formed by the traditional Mylar film, due to its hot-melt bonding structure, cannot buffer external loads through deformation, making the active coating of the electrode prone to peeling under pressure, the current collector microcracks to propagate, and even causing local rupture of the separator, forming a potential short-circuit channel. Utility Model Content

[0005] In view of this, and to solve the above problems, the purpose of this utility model is to provide a Mylar membrane structure, comprising:

[0006] A membrane body for wrapping the battery cell;

[0007] At least one covering strip, one end of each covering strip is connected to the membrane body, and the other end of each covering strip extends outward to form a connecting portion;

[0008] At least one protective sheet is fixedly disposed on the covering strip, and the protective sheet is disposed near the end of the battery cell.

[0009] In another preferred embodiment, the membrane body has at least one groove, and one end of the covering strip is connected to the inside of the groove.

[0010] In another preferred embodiment, the protective sheet has a plurality of first through holes.

[0011] In another preferred embodiment, the covering strip is provided with a plurality of second through holes, and the first through holes and the second through holes are connected.

[0012] In another preferred embodiment, the surface of the membrane body is provided with at least one feature portion.

[0013] In another preferred embodiment, the membrane body includes: a plurality of membrane portions connected in sequence, and a first fold between each pair of adjacent membrane portions, wherein the membrane body is foldably surrounded on the outside of the battery cell through the first fold.

[0014] In another preferred embodiment, at least two of the membrane portions are disposed opposite to each other, one of the two membrane portions being connected to one end of the covering strip, and the other of the two membrane portions being connected to the connecting portion of the covering strip.

[0015] In another preferred embodiment, the membrane body has two opposing edges, and at least one of the covering strips is provided at each edge.

[0016] In another preferred embodiment, the end of the battery cell has a tab, and the protective sheet is offset from the tab.

[0017] The purpose of this invention is also to provide a battery comprising the Mylar membrane structure described in any one of the above.

[0018] Because this utility model adopts the above-mentioned technical solution, it has the following positive effects compared with the prior art:

[0019] By applying this utility model, a Mylar film structure and a corresponding battery suitable for encapsulating and protecting battery cells are provided. The Mylar film structure forms an overall covering of the battery cell through a bendable film body, and the covering strip connected to the film body forms a binding on the ends of the battery cell. At the same time, the protective sheet forms a rigid protection for the battery cell, thereby improving the safety performance and reliability of the battery. The Mylar film structure has strong stability and high assembly efficiency. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of a Mylar membrane structure according to the present invention;

[0021] Figure 2 This is a schematic diagram of the main body of a Mylar membrane structure according to this utility model;

[0022] Figure 3 This is a schematic diagram of a Mylar membrane structure coating strip according to the present invention;

[0023] Figure 4 This is a schematic diagram of a protective sheet with a Mylar membrane structure according to this utility model;

[0024] Figure 5 This is a schematic diagram of the first fold of a Mylar membrane structure according to the present invention.

[0025] In the attached image:

[0026] 1. Membrane body; 2. Covering strip; 3. Connecting part; 4. Protective sheet; 5. Groove; 6. First through hole; 7. Second through hole; 8. Feature part; 9. Membrane part; 10. First crease; 11. Edge; 12. First part; 13. Second part; 14. Third part; 15. Fourth part; 16. Fifth part; 17. Straight part; 18. Bending part. Detailed Implementation

[0027] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0028] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front", "back", "horizontal", and "vertical" are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] It should be noted that the terms "horizontal" and "vertical" in this utility model are used to describe approximate positional relationships, and not strictly "horizontal plane" or "vertical plane".

[0030] like Figure 1The diagram illustrates a preferred embodiment of a Mylar film structure, comprising: a film body 1 for wrapping a battery cell; at least one covering strip 2, one end of which is connected to the film body 1, and the other end of which extends outward to form a connecting portion 3; and at least one protective sheet 4, which is fixedly disposed on the covering strip 2 and positioned near the end of the battery cell. Further, the film body 1 serves as the main structure for wrapping the entire Mylar film around the battery cell, and the covering strip 2 extends to the end of the battery cell, providing additional restraint. The protective sheet 4 provides protection for the end of the battery cell, preventing the cell from being squeezed by the lower plastic, retaining frame, or other structures within the battery, thus preventing material loss, especially avoiding pressure on the negative electrode of the battery cell. The covering strip 2 both participates in wrapping the end of the battery and serves as the mounting base for the protective sheet 4. This allows the entire Mylar film to effectively encapsulate and protect the battery cell, ensuring its safety performance.

[0031] Furthermore, in a preferred embodiment, the connecting portion 3 at the other end of the covering strip 2 is used to fix it to a corresponding position by a corresponding connecting means. This position allows the covering strip 2 to stably cover at least a portion of the end of the battery cell, thereby enabling the Mylar film structure to better cover the entire battery cell. More specifically, the Mylar film structure can be wrapped around the bottom surface, two pairs of side surfaces, and top surface of the battery cell by bending the film body 1. That is, the film body 1 surrounds the outer periphery of the battery cell and exposes the two end faces of the battery cell. At this time, bending the covering strip 2 can cover the end of the battery cell with the protective sheet 4, and one end of the covering strip 2 is fixed to one side of the film body 1, while the connecting portion 3 at the other end of the covering strip 2 is subsequently fixed to the other side of the film body 1. Alternatively, the connecting portion 3 at the other end of the covering strip 2 can be fixed to the other side of the battery cell; or, after the Mylar membrane structure covers at least one side of the battery cell, another relatively independent membrane structure is attached to the other side of the battery cell, and the connecting portion 3 at the other end of the covering strip 2 is fixed to the other membrane structure.

[0032] Furthermore, as a preferred embodiment, the connecting portion 3 of the covering strip 2 can be connected to a designated location by hot stamping, ultrasonic welding, or adhesive bonding.

[0033] Furthermore, as a preferred embodiment, the membrane body 1, the covering strip 2, and the protective sheet 4 are connected sequentially by hot stamping or ultrasonic welding.

[0034] Furthermore, as a preferred embodiment, the membrane body 1 is preferably arranged in a rectangular sheet structure.

[0035] like Figure 2As shown, further, in a preferred embodiment, the membrane body 1 has at least one groove 5, and one end of the covering strip 2 is connected to the inside of the groove 5.

[0036] Furthermore, as a preferred embodiment, the groove 5 is recessed relative to the surface of the membrane body 1.

[0037] Furthermore, as a preferred embodiment, the groove 5 has at least a bottom surface and a circumferential surface surrounding the bottom surface, the circumferential surface being at least partially inclined to facilitate the extension of the covering strip 2 from the inside of the groove 5 outward.

[0038] Furthermore, as a preferred embodiment, a chamfer may be provided at the upper end of the circumferential surface to optimize the extension of the covering strip 2.

[0039] Furthermore, as a preferred embodiment, the interior of the groove 5 is preferably arranged in an inverted truncated quadrangular pyramid shape.

[0040] like Figure 4 As shown, further, in a preferred embodiment, the protective sheet 4 has a plurality of first through holes 6. Furthermore, the first through holes 6 facilitate the wetting of the cell interior by the electrolyte during battery assembly and the vacuum pumping process; that is, the first through holes 6 are used for the passage of electrolyte and the passage of gas.

[0041] Furthermore, as a preferred embodiment, the protective sheet 4 is made of a rigid material.

[0042] Furthermore, as a preferred embodiment, the protective sheet 4 is preferably made of a high-molecular corrosion-resistant material such as PI, PET, or PP.

[0043] Furthermore, as a preferred embodiment, the protective sheet 4 is preferably fixed at the middle position along the length of the covering strip 2.

[0044] Furthermore, as a preferred embodiment, the protective sheet 4 is preferably configured as a rounded rectangular sheet structure.

[0045] like Figure 3 As shown, further, in a preferred embodiment, the covering strip 2 is arranged in a long strip shape and has a certain degree of bendability so that it can move the protective sheet 4 to a position close to the end of the battery cell.

[0046] Furthermore, in a preferred embodiment, the length direction of the covering strip 2 is perpendicular to the length direction of the protective sheet 4.

[0047] Furthermore, as a preferred embodiment, the covering strip 2 is provided with at least one second crease so that the covering strip 2 can be bent and the protective sheet 4 can be moved to the corresponding position, and the connecting portion 3 can be bent to the indicated position.

[0048] Furthermore, as a preferred embodiment, the covering strip 2 includes: a straight portion 17 and a bent portion 18 connected to each other. The bent portion 18 is disposed in a bent manner in the groove 5 and has a tendency to extend upward in the circumferential direction from the bottom of the groove 5. One end of the straight portion 17 is disposed above the surface of the membrane body 1, and the other end of the straight portion 17 extends outward and protrudes from the edge 11 of the membrane body 1.

[0049] Furthermore, as a preferred embodiment, the bend 18 is at least mostly not protruding from or flush with the upper end of the groove 5, i.e., the surface of the membrane body 1, to avoid the covering strip 2 interfering with the installation of the battery cell.

[0050] Furthermore, as a preferred embodiment, the inner contour of the groove 5 is slightly larger than the width of the covering strip 2 in the width direction. Further, this width difference can be 1 to 3 mm to compensate for possible tolerances during assembly.

[0051] Furthermore, in a preferred embodiment, the covering strip 2 has a plurality of second through holes 7, and the first through holes 6 and the second through holes 7 are connected. Furthermore, after the covering strip 2 is bent, it is located inside or outside the protective sheet 4, allowing corresponding gas or fluid to pass through the first through holes 6 and the second through holes 7 in sequence.

[0052] Furthermore, as a preferred embodiment, the first through hole 6 and / or the second through hole 7 are preferably arranged in a circular shape.

[0053] Furthermore, as a preferred embodiment, the inner diameter of the first through hole 6 and / or the second through hole 7 is preferably 2 mm to 5 mm.

[0054] Furthermore, as a preferred embodiment, a plurality of first through holes 6 are arranged in a dense and uniform array on the protective sheet 4, and a plurality of second through holes 7 are arranged in a dense and uniform array on the covering strip 2.

[0055] Furthermore, as a preferred embodiment, the array shape described above is preferably rectangular or hexagonal, etc.

[0056] Furthermore, in a preferred embodiment, the surface of the membrane body 1 is provided with at least one feature portion 8. Furthermore, the feature portion 8 on the membrane body 1 facilitates the pre-positioning of the Mylar membrane structure, enabling subsequent bending and shell insertion operations.

[0057] Furthermore, as a preferred embodiment, the feature portion 8 is a pattern that is easy for operators or vision devices to identify. The feature portion 8 may be a hole structure, a raised structure, or a marking point with a color different from that of the membrane body 1.

[0058] Furthermore, as a preferred embodiment, the hole structure is preferably a blind hole.

[0059] Furthermore, as a preferred embodiment, the feature portion 8 of the membrane body 1 is preferably provided in four parts and is respectively provided at the four corners near the membrane body 1.

[0060] Furthermore, as a preferred embodiment, at least one or more of the four feature portions 8 have different distances from the edge 11 of the membrane body 1 for easy identification. Further, the edge 11 may be the long side and / or the wide side of the membrane body 1.

[0061] like Figure 5 As shown, further, in a preferred embodiment, the membrane body 1 includes: a plurality of membrane portions 9, which are connected sequentially, and a first fold 10 is provided between each pair of adjacent membrane portions 9. The membrane body 1 can be bent to surround the outside of the battery cell through the first fold 10. Furthermore, the first fold 10 facilitates bending of the membrane body 1 to precisely wrap around the battery cell.

[0062] Furthermore, as a preferred embodiment, the first crease 10 is at least provided on the surface of the membrane body 1, and preferably the first crease 10 can also extend to the edge of the membrane body 1 in the thickness direction.

[0063] Furthermore, in a preferred embodiment, the plurality of membrane portions 9 include: a first portion 12, a second portion 13, a third portion 14, a fourth portion 15, and a fifth portion 16 connected in sequence, wherein the third portion 14 is disposed at the bottom of the cell, the second portion 13 and the fourth portion 15 are respectively disposed on both sides of the cell, a covering strip 2 is disposed on the second portion 13 and / or the fourth portion 15, and the first portion 12 and the fifth portion 16 are stacked on or joined to the top of the cell.

[0064] Furthermore, in a preferred embodiment, at least two membrane portions 9 are disposed opposite to each other, one of the two membrane portions 9 being connected to one end of the covering strip 2, and the other of the two membrane portions 9 being connected to the connecting portion 3 of the covering strip 2. That is, the second portion 13 is connected to one end of the covering strip 2, and the other end of the covering strip 2 is connected to the fourth portion 15.

[0065] Furthermore, as a preferred embodiment, the membrane body 1 has two opposing edges 11, and at least one covering strip 2 is provided at each edge 11.

[0066] Furthermore, as a preferred embodiment, each edge 11 is preferably provided to extend along the width direction of the membrane body 1, and each covering strip 2 is preferably provided to extend along the length direction of the membrane body 1.

[0067] Furthermore, as a preferred embodiment, a plurality of covering strips 2 may be provided at each edge 11, and the plurality of covering strips 2 are arranged sequentially at intervals along the width direction of the membrane body 1.

[0068] Furthermore, as a preferred embodiment, such as Figure 1 As shown, four parallel covering strips 2 are preferably provided at each of the two edges 11. Correspondingly, the membrane body 1 has four grooves 5 near the edges 11 to match the four covering strips 2.

[0069] Furthermore, as a preferred embodiment, the end of the battery cell has a tab, and the protective sheet 4 is offset from the tab.

[0070] Furthermore, in a preferred embodiment, when the membrane body 1 covers the battery cell, the membrane body 1 is bent so that the second part 13 and the fourth part 15 are positioned opposite each other. At least one covering strip 2 can be provided at the same edge 11 of the second part 13 and the fourth part 15. Since the battery cell is located between the second part 13 and the fourth part 15, the bending of the covering strip 2 on the second part 13 is opposite to the bending of the covering strip 2 on the fourth part 15, so that both covering strips 2 can cover the end of the battery cell.

[0071] Furthermore, as a preferred embodiment, when the second part 13 and the fourth part 15 are in opposite positions, they can preferably be considered as both being arranged vertically; and the two covering strips 2 are arranged sequentially in the vertical direction so that the two covering strips 2 are staggered at the ends of the battery cell. Even further, each of the two covering strips 2 is provided with a protective sheet 4, and the two protective sheets 4 are also arranged sequentially in the vertical direction, and a gap can be formed between adjacent two covering strips 2 and / or two protective sheets 4. This gap is used for the passage of the battery cell's tabs, that is, the positions of the covering strips 2 and protective sheets 4 at the ends of the battery cell should not interfere with the battery cell's tabs.

[0072] Furthermore, as a preferred embodiment, when assembling the battery cell in this Mylar membrane structure, the battery cell is first placed on the third part 14 of the membrane body 1. Then, the membrane body 1 is folded using a mechanical gripper or manually through the first crease 10 to cover at least two sides, the top surface, and the bottom surface of the battery cell. Next, the top of the membrane body 1, i.e., the first part 12 and the fifth part 16, is bonded and fixed using tape or other adhesive structures. Then, the entire membrane body 1 and the battery cell are clamped and fixed using grippers or tooling. The covering strip 2 is then bent so that the protective sheet 4 is moved to the end near the battery cell. Finally, the outer periphery of the fully covered Mylar membrane structure is wrapped and fixed using multiple layers of tape. After completing the above steps, it can be further heat-fused and fixed to the battery's stop frame and / or lower plastic structure. The stop frame and lower plastic are common components in existing battery structures and will not be described further here.

[0073] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model.

[0074] Based on the above, this utility model also has the following embodiments:

[0075] In a further embodiment of the present invention, a battery includes any of the Mylar membrane structures described above.

[0076] In a further embodiment of the present invention, the battery further includes a casing and a cell, wherein the Mylar membrane structure covers the outside of the cell and the casing is fitted over the outside of the Mylar membrane structure.

[0077] In a further embodiment of this utility model, the battery cell is preferably a stacked cell. Furthermore, by binding the membrane body 1 and the covering strip 2 to the outside of the battery cell, the problem of easy delamination and misalignment at the ends of the stacked cell can be effectively improved, thereby ensuring battery performance.

[0078] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A Mylar membrane structure, characterized in that, include: A membrane body for wrapping the battery cell; At least one covering strip, one end of each covering strip is connected to the membrane body, and the other end of each covering strip extends outward to form a connecting portion; At least one protective sheet is fixedly disposed on the covering strip, and the protective sheet is disposed near the end of the battery cell.

2. The Mylar membrane structure according to claim 1, characterized in that, The membrane body has at least one groove, and one end of the covering strip is connected to the inside of the groove.

3. The Mylar membrane structure according to claim 1, characterized in that, The protective sheet has several first through holes.

4. The Mylar membrane structure according to claim 3, characterized in that, The covering strip has several second through holes, and the first through holes and the second through holes are connected.

5. The Mylar membrane structure according to claim 1, characterized in that, The surface of the membrane body is provided with at least one feature.

6. The Mylar membrane structure according to claim 1, characterized in that, The membrane body includes: a plurality of membrane portions connected in sequence, and a first fold between each pair of adjacent membrane portions. The membrane body can be bent to surround the outside of the battery cell through the first fold.

7. The Mylar membrane structure according to claim 6, characterized in that, At least two membrane portions are disposed opposite to each other, one of the two membrane portions being connected to one end of the covering strip, and the other of the two membrane portions being connected to the connecting portion of the covering strip.

8. The Mylar membrane structure according to claim 1, characterized in that, The membrane body has two opposing edges, and at least one covering strip is provided at each edge.

9. The Mylar membrane structure according to claim 1, characterized in that, The battery cell has tabs at its end, and the protective sheet is offset from the tabs.

10. A battery, characterized in that, Includes the Mylar membrane structure described in any one of claims 1 to 9 above.

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