Secondary battery

Abstract

The utility model provides a secondary battery, including a battery body and an insulating film, wherein the battery body has an end face and a first side face and a second side face adjacent to the end face; the insulating film has a first insulating region and a second insulating region, wherein the first insulating region is folded along the first side face toward the end face to form a first extension portion, wherein the first extension portion at least covers a portion of the end face, and the second insulating region is folded along the second side face toward the end face to form a second extension portion, wherein the second extension portion covers a portion of the first extension portion in a direction perpendicular to the end face to form an insulating film overlapping region, wherein a fusion portion is formed in the insulating film overlapping region. The insulating film in the insulating film overlapping region is melted, and the melted insulating film is solidified after cooling, so that the connection between the insulating films in the fusion portion is firm and the thickness is reduced, thereby preventing the insulating film from warping due to bonding failure after the insulating film is bonded to the end face due to temperature increase, thereby improving the reliability and service life of the battery.

Description

Technical Field

[0001] The utility model relates to the field of batteries, in particular to a secondary battery. Background Art

[0002] Currently, power lithium batteries occupy a very high market share. Usually, the batteries are coated with a layer of protective film before they come off the production line to achieve insulation protection and prevent external short circuits and corrosion.

[0003] As disclosed in CN220492118U, in order to ensure the insulation between the electrode assembly and the shell, the surface of the electrode assembly is generally wrapped with an insulating film. However, in the process of coating the battery with the insulating film, the aluminum shell surface that does not contain the pole will be completely coated with the insulating film, but the top cover surface containing the pole can only be coated with the outer circle in order to avoid the position of the pole. This circle of insulating film is called a flange. Normally, the flange is narrow. After the battery is bonded, the insulating film will overlap at the corner, of which only the innermost insulating film will stick to the battery shell, and the remaining insulating film will be bonded to each other and then bulge outward. At this time, even if the top patch is attached, the top patch is easily lifted up by the bulging part of the overlapping insulating film, causing the top patch to warp, which will not only cause appearance problems, but more seriously will lead to insulation failure, which significantly increases the probability of battery external short and corrosion.

[0004] Therefore, the prior art lacks a battery that can prevent the top sheet from warping. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a battery in order to overcome the defect that the top patch of the battery shell of the prior art is easy to be lifted.

[0006] The utility model solves the above technical problems through the following technical solutions:

[0007] A secondary battery comprises a battery body and an insulating film, wherein the battery body comprises an end face and a first side face and a second side face adjacent to the end face; the insulating film comprises a first insulating region and a second insulating region, the first insulating region is folded along the first side face toward the end face to form a first extension portion, the first extension portion at least covers a portion of the end face, and the second insulating region is folded along the second side face toward the end face to form a second extension portion;

[0008] Wherein, along a direction perpendicular to the end surface, the second extension portion covers a portion of the first extension portion to form an insulating film overlapping region, and a fusion portion is formed in the insulating film overlapping region.

[0009] In the present scheme, the fusion portion formed in the overlapping area of ​​the insulating films can be realized by hot pressing or other welding technology, and the insulating films in the overlapping area of ​​the insulating films are melted, and the melted insulating films are solidified after cooling, so that the connection between the insulating films in the fusion portion is firm and seamless, thereby preventing the insulating film from warping due to bonding failure after the insulating film is bonded to the end face due to temperature increase; the fusion portion enables the battery to maintain good insulation properties in high temperature and high humidity environments, thereby improving the reliability and service life of the battery.

[0010] Preferably, the first side surface, the second side surface and the end surface have a transition zone, the end surface has at least three layers of insulating film near the transition zone, and the first extension portion and the second extension portion have a layer of insulating film in a direction away from the transition zone.

[0011] Preferably, along a direction perpendicular to the end surface, the fusion portion fuses at least two layers of the insulation film.

[0012] Furthermore, the fusion portion is fused with the metal of the end surface.

[0013] Furthermore, the insulating film at the fusion portion covers the metal at the end surface after fusion;

[0014] And / or, the thickness of the fusion portion is not less than the thickness of the insulating film.

[0015] Preferably, the shape of the fusion portion is circular or square; when the fusion portion is square, the side length of the square is 1-8 mm; when the fusion portion is circular, the diameter of the circle is 6-10 mm.

[0016] Preferably, the battery body comprises:

[0017] A shell, wherein an end of the shell is provided with an opening, and the first side surface and the second side surface are two adjacent outer side surfaces of the shell;

[0018] an electrode assembly, wherein the electrode assembly is disposed in the housing;

[0019] An end cover closes the opening to form the end surface.

[0020] Further, the secondary battery further comprises an end cover insulating patch, the end cover insulating patch is arranged on the end cover, and the end cover insulating patch covers the first extension portion and the second extension portion; and / or,

[0021] The first extension portion and the second extension portion are both arranged on the end cover.

[0022] Furthermore, the end cover is in a quadrilateral shape, and the area on the end cover close to the arc transition area of ​​the quadrilateral has a fusion portion.

[0023] Furthermore, the insulating film has a joint portion on a side surface of the shell, the joint portion is stacked with at least two layers of insulating films, and the joint portion also has a side fusion portion.

[0024] Furthermore, the side fusion portions are distributed at intervals on the joint portion.

[0025] On the basis of conforming to the common sense in the art, the above preferred technical solutions can be freely combined to obtain the preferred embodiments of the present application.

[0026] The positive progressive effect of the utility model is that the fusion portion formed in the overlapping area of ​​the insulating film can be realized by hot pressing or other welding technology, the insulating film in the overlapping area of ​​the insulating film is melted, and the melted insulating film is solidified after cooling, so that the connection between the insulating films in the fusion portion is firm and seamless and the thickness of the overlapping insulating film at this location is reduced, thereby preventing the insulating film from warping due to bonding failure after the insulating film is bonded to the end face due to temperature increase; the fusion portion enables the battery to maintain good insulation performance in high temperature and high humidity environments, thereby improving the reliability and service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The diagram is a schematic diagram of the explosion structure of a secondary battery in the prior art of the utility model.

[0028] Figure 2 It is a schematic diagram of the three-dimensional structure of a secondary battery in the prior art of the utility model.

[0029] Figure 3 for Figure 2 Schematic diagram of the enlarged local structure at A.

[0030] Figure 4 It is a schematic diagram of the three-dimensional structure of a secondary battery after hot stamping according to an embodiment of the utility model.

[0031] Figure 5 for Figure 4 Schematic diagram of the enlarged local structure at B.

[0032] Figure 6 It is a schematic diagram of the hot-blanking manufacturing process structure of a secondary battery according to an embodiment of the utility model.

[0033] Figure 7 It is a structural schematic diagram of another hot stamping manufacturing process of a secondary battery according to an embodiment of the utility model.

[0034] Description of Reference Numerals

[0035] Secondary battery 100

[0036] Battery body 10

[0037] End face 11

[0038] First side 12

[0039] Second side 13

[0040] Housing 14

[0041] Electrode assembly 15

[0042] Insulation film 20

[0043] The first insulating region 22

[0044] The first extension portion 220

[0045] The second insulating region 23

[0046] The second extension portion 230

[0047] Insulating film overlapping region 30

[0048] Fusion section 301

[0049] Transition Zone 40

[0050] End cap insulation patch 50

[0051] Arc transition zone 60

[0052] Perm 70 DETAILED DESCRIPTION

[0053] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0054] This embodiment provides a secondary battery 100, such as Figure 1-Figure 3 As shown, the secondary battery 100 includes a battery body 10, wherein the battery body 10 includes a shell 14, an electrode assembly 15 and an end cover, an end of the shell 14 is provided with an opening, a first side surface 12 and a second side surface 13 are two adjacent outer side surfaces of the shell 14; the electrode assembly 15 is arranged in the shell 14; the end cover closes the opening to form an end surface 11, and the battery body 10 has an end surface 11 and a first side surface 12 and a second side surface 13 adjacent to the end surface 11.

[0055] The secondary battery 100 further includes an insulating film 20, such as Figure 1As shown, the insulating film 20 has a first insulating region 22 and a second insulating region 23. The first insulating region 22 is folded along the first side surface 12 toward the end surface 11 to form a first extension portion 220. The first extension portion 220 at least covers a portion of the end surface 11. The second insulating region 23 is folded along the second side surface 13 toward the end surface 11 to form a second extension portion 230. In this regard, along a direction C perpendicular to the end surface 11, the second extension portion 230 covers a portion of the first extension portion 220 to form an insulating film overlapping region 30. A fusion portion 301 is formed in the insulating film overlapping region 30.

[0056] Among them, the fusion portion 301 can have various forms. When the first extension portion 220 and the second extension portion 230 form a crease during the folding process, when the crease is a straight line and / or a curve, the fusion portion 301 is arranged in an area on the end surface 11 close to the intersection of the straight line and / or the curve; in other preferred embodiments, when the crease forms a polygon, the area on the end surface 11 close to the arc transition zone 60 of the polygon is provided with the fusion portion 301.

[0057] The fusion part 301 formed in the insulation film overlap area 30 can be realized by hot pressing or other welding technology, and the insulation film 20 in the insulation film overlap area 30 is melted, and the melted insulation film 20 is solidified after cooling, so that the connection between the insulation films 20 in the fusion part 301 is firm and seamless, and the thickness of the overlapping insulation film 20 at this place is reduced. In this way, the insulation film 20 is prevented from warping due to adhesion failure after the insulation film 20 is bonded to the end face 11 due to temperature rise; the fusion part 301 enables the battery to maintain good insulation performance in a high temperature and high humidity environment, thereby improving the reliability and service life of the battery.

[0058] By applying the insulating film 20 on the end surface 11 and the first side surface 12 and the second side surface 13 of the battery body 10, stronger insulation protection is provided, which can prevent internal and external short circuits of the battery, thereby improving the safety of the battery.

[0059] In this embodiment, the first side surface 12, the second side surface 13 and the end surface 11 have a transition zone 40, and the end surface 11 has at least three layers of insulating films 20 in the area close to the transition zone 40. In the direction away from the transition zone 40, the first extension portion 220 and the second extension portion 230 have a layer of insulating film 20, which helps to prevent the battery from short-circuiting in this area, improves the insulation of this area, saves insulating materials, and helps to reduce the cost of the battery.

[0060] In this embodiment, the end surface 11 has three layers of insulating films 20 near the transition region 40 as an example. Figure 2 , Figure 3As shown, by fusing at least two layers of insulating films 20, the insulating film overlap area 30 is a right triangle, and the length of the right angle side is 1mm to 8mm, preferably 2-5mm. The fusion portion 301 improves the insulation performance so that a firm connection is formed between the insulating films 20 at this position, and reduces the thickness of the insulating film 20 at this position, so that the patch attached to the fusion portion 301 is not easy to warp. In other embodiments, the fusion portion 301 can also fuse three, four or more layers of insulating films 20 in a direction perpendicular to the end face 11.

[0061] Furthermore, the fusion portion 301 can be fused with the metal of the end face 11, so that the fusion portion 301 firmly connects the insulating film 20 and the metal part of the battery end face 11, and this connection is more reliable than the traditional bonding or mechanical fixing method. The fused connection part can withstand greater stress and vibration, effectively preventing the separation or damage between the insulating film 20 and the metal. The fusion of the fusion portion 301 and the metal of the end face 11 makes the battery more adaptable to the external environment. Whether it is a high temperature or low temperature environment, the fusion portion 301 can maintain stable connection performance, ensuring the normal operation and performance of the battery under various environmental conditions.

[0062] Furthermore, the insulating film 20 at the fusion portion 301 covers the metal at the end face 11 after fusion, forming a protective layer that can effectively prevent the metal part from being corroded and damaged by the external environment or the chemical substances inside the battery. The insulating film 20 covers the metal part, enhancing the insulation performance of the battery end. This helps to reduce the risk of internal short circuits in the battery during operation and improve the stability and reliability of the battery.

[0063] The thickness of the fusion portion 301 is not less than the thickness of the insulating film 20. The fusion portion 301 has sufficient thickness to ensure that the insulation performance of the battery end is significantly improved, reduce the risk of internal short circuit of the battery during operation, and enhance the stability and reliability of the battery. If fused with the metal of the end face 11, the fused connection part has a stronger structural strength, which helps the battery resist external impact, vibration and other mechanical stresses. Even in harsh working environments, the battery still maintains the integrity and stability of the battery end.

[0064] Among them, the shape of the fusion part 301 can be a square, and the side length of the square is 1-8mm; the fusion part 301 is hot-ironed with a square ironing head 70. The specific hot-ironing process is as follows: the first step is to fix the position of the secondary battery 100. Specifically, when the secondary battery 100 is coated, the flange is controlled to be 3mm, so the corner will form a right triangle with a right angle of 3mm*3mm. After wrapping the insulating film 20, before attaching the end cover insulating patch 50, the secondary battery 100 is placed on the operating table, the end cover surface is facing the hot-ironing probe, and then the secondary battery 100 is fixed. The second step is hot-ironing. The specific process steps are as follows: adjust the four hot-ironing ironing heads 70 and the insulating film overlapping area 30 near the four corners to correspond one to one. The hot-ironing ironing head 70 is designed to be a square probe with a side length of 3mm. The hot-ironing temperature is set to 135°C, the hot pressing time is 3s, and the hot pressing pressure is 0.4Mpa. The relative positions between the four hot-ironing heads 70 are designed to be adjustable, so that they can be compatible with secondary batteries 100 of different sizes.

[0065] In other preferred embodiments, other process parameters may be used. Specifically, during hot stamping, the hot stamping head 70 may preferably be made of copper material with good thermal conductivity; the hot stamping temperature is between 100 and 200°C, preferably 120 to 150°C; the hot pressing time is 1 to 10 seconds, preferably 2 to 4 seconds; the pressure is 0.1 to 1 MPa, preferably 0.3 to 0.5 MPa. The relative position of the hot stamping head 70 is designed to be adjustable, so that it can be compatible with secondary batteries 100 of different sizes.

[0066] In other preferred embodiments, when the fusion portion 301 is circular, the diameter of the circle is 6-10 mm. A circular hot stamping head 70 is used, with a diameter or width of 1 to 8 mm, preferably 2 to 5 mm. Therefore, a circular or square hot stamping head 70 is selected, and the head 70 is preferably made of copper with good thermal conductivity; the hot stamping temperature is 100 to 200°C, preferably 120 to 150°C; the hot pressing time is 1 to 10s, preferably 2 to 4s; the pressure is 0.1 to 1Mpa, preferably 0.3 to 0.5Mpa. After hot stamping, the insulating film overlap area 30 does not exceed the surrounding area of ​​the end cover insulating patch 50, otherwise it will cause edge damage and lead to abnormal insulation withstand voltage.

[0067] The shell 14 may be open at one end or at both ends. When one end is open, the heat Figure 6 As shown, when both ends of the shell 14 are open, the two ends can be hot-stamped in two steps, or the fusion portions 301 at both ends can be hot-stamped at both ends of the shell 14 in one step, as shown in FIG. Figure 7 The blanching probes can also be set up as 2*4 probes, 4 on each side, so that the blanching process can be completed in one go without changing the direction in the middle.

[0068] Furthermore, the secondary battery 100 also includes an end cap insulating patch 50, which is disposed on the end cap and covers the first extension portion 220 and the second extension portion 230; the presence of the end cap insulating patch 50 increases the insulation between the internal components of the battery and other external electrical connections, thereby improving the safety of the battery.

[0069] The first extension part 220 and the second extension part 230 are both arranged on the end cap. Specifically, the end cap insulating patch 50 is attached to the first extension part 220 and the second extension part 230, and covers the first extension part 220 and the second extension part 230 and the fusion part 301, so that the end cap insulating patch 50 and the insulating film 20 on the side are connected as a whole, which improves the insulation performance of the outer surface of the secondary battery 100 as a whole. Compared with the process of using the insulating film 20 to attach the end cap, the process of attaching the end cap insulating patch 50 to the first extension part 220 and the second extension part 230 simplifies the production process of the battery, and the specific attachment can be made by bonding or other methods.

[0070] Further, the end cap is quadrilateral, such as Figure 4 , Figure 5 As shown, the area near the quadrilateral arc transition area 60 on the end cap has a fusion portion 301. When the insulating film 20 is attached to the position of the arc transition area 60, it is easy for multiple insulating films 20 to overlap each other. The bonding between the insulating films 20 is not firm or the overlapping of multiple layers increases the thickness, which easily causes the end cap insulating patch 50 to warp. The fusion portion 301 makes the connection between the multiple insulating films 20 tighter, and the insulation films 20 after bonding will not separate from each other, resulting in an increase in the thickness of the insulating film 20; in addition, the fusion process allows the multiple insulating films 20 to fuse with each other, reducing the thickness between the multiple insulating films 20, and reducing the risk of the end cap insulating patch 50 attached to the multiple insulating films 20 warping.

[0071] Furthermore, the insulating film 20 has a joint portion on the side of the housing 14, and the joint portion is stacked with at least two layers of insulating films 20, and the joint portion also has a side fusion portion (not shown in the figure). The joint portion allows the insulating film 20 to completely cover the side of the housing 14, thereby improving the insulation of the housing 14. However, if the joint is used for a long time, the upper insulating film 20 may be warped due to the failure of the bonding of the upper insulating film 20. The side fusion portion 301 allows the insulating films 20 at the joint portion to be fused together into a whole, thereby reducing the risk of warping of the upper insulating film 20 at the joint portion.

[0072] The side fusion portions are spaced apart on the joint, and when spaced apart, they can distribute stress more evenly across the joint. This helps reduce stress concentration at certain specific points, thereby preventing the insulating film 20 from tearing or breaking at these points. In addition, the spaced apart side fusion portions can provide more connection points, making the connection between the insulating films 20 at the joint more secure.

[0073] Although the specific implementations of the utility model are described above, those skilled in the art should understand that this is only an example, and the protection scope of the utility model is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the utility model, but these changes and modifications fall within the protection scope of the utility model.

Claims

1. A secondary battery, characterized in that: include: A battery body having an end surface and a first side surface and a second side surface adjacent to the end surface; An insulating film having a first insulating region and a second insulating region, wherein the first insulating region is folded along the first side surface toward the end surface to form a first extension portion, the first extension portion at least covers a portion of the end surface, and the second insulating region is folded along the second side surface toward the end surface to form a second extension portion; Wherein, along a direction perpendicular to the end surface, the second extension portion covers a portion of the first extension portion to form an insulating film overlapping region, and a fusion portion is formed in the insulating film overlapping region.

2. The secondary battery according to claim 1, wherein: The first side surface, the second side surface and the end surface have a transition zone, the end surface has at least three layers of insulating film in a region close to the transition zone, and the first extension portion and the second extension portion have a layer of insulating film in a direction away from the transition zone.

3. The secondary battery according to claim 2, characterized in that: The fusion portion fuses at least two layers of the insulating films in a direction perpendicular to the end surface.

4. The secondary battery according to claim 3, characterized in that: The fusion portion is fused to the metal of the end surface.

5. The secondary battery according to claim 3, characterized in that: The insulating film at the fusion portion is fused to cover the metal at the end surface; And / or, the thickness of the fusion portion is not less than the thickness of the insulating film.

6. The secondary battery according to claim 1, wherein: The shape of the fusion portion is circular or square; When the fusion portion is square, the side length of the square is 1-8 mm; when the fusion portion is circular, the diameter of the circle is 6-10 mm.

7. The secondary battery according to claim 1, wherein: The battery body comprises: A shell, wherein an end of the shell is provided with an opening, and the first side surface and the second side surface are two adjacent outer side surfaces of the shell; an electrode assembly, wherein the electrode assembly is disposed in the housing; An end cover closes the opening to form the end surface.

8. The secondary battery according to claim 7, wherein: The secondary battery further includes an end cover insulating patch, which is disposed on the end cover and covers the first extension portion and the second extension portion; and / or, The first extension portion and the second extension portion are both arranged on the end cover.

9. The secondary battery according to claim 7, characterized in that: The end cover is in a quadrilateral shape, and areas of the end cover close to the arc transition area of ​​the quadrilateral all have fusion portions.

10. The secondary battery according to claim 7, wherein: The insulating film has a joint portion on a side surface of the housing, the joint portion is formed by laminating at least two insulating films, and the joint portion also has a side fusion portion.

11. The secondary battery according to claim 10, characterized in that: The side fusion portions are spaced apart on the joint portion.

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