Battery, shell thereof and battery module

Abstract

The utility model relates to the technical field of battery production, and discloses a battery, a shell of the battery and a battery module, the battery shell comprises a shell with an opening at one end, the inner peripheral side wall of the shell is coated with a composite layer, the composite layer comprises an insulating layer and a bonding layer connecting the insulating layer and the shell, the insulating layer has ductility, and the bonding layer is coated with a coating layer. And the thickness of the composite layer is greater than or equal to 0.02 mm. According to the battery, the inner peripheral side wall of the shell is coated with the composite layer, and the composite layer comprises the insulating layer and the bonding layer connected with the insulating layer and the shell, so that the inner peripheral side wall of the shell is insulated, and short circuit caused by direct contact between the metal shell and the positive tab of the battery can be avoided. Meanwhile, the insulating layer has ductility, and the thickness of the composite layer is greater than or equal to 0.02 mm, so that when the battery is punctured, the insulating layer can be attached to the surface of a steel needle to form an insulating protection layer, direct short circuit in the battery caused by the fact that a positive electrode material and a negative electrode material are conducted by a needle tip is avoided, and the puncturing passing rate of the battery is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a battery, a shell thereof and a battery module. BACKGROUND

[0002] With the continuous development of new energy, the energy density requirement of batteries is higher and higher. Among them, cylindrical lithium batteries, as a commonly used power selection scheme, have the advantages of large capacity, long service life, high safety performance, high voltage, no memory effect, small internal resistance and the like.

[0003] However, with the increase of energy density, the thermal stability and safety of lithium batteries decrease, and the lithium batteries are prone to explosion due to short circuit, thereby limiting the application of high-energy-density lithium batteries. Among them, there are mainly two forms of short circuit, one is that the metal shell is in contact with the positive electrode ear to cause short circuit, and the other is that when the needle is pierced, the metal needle tip penetrates the positive and negative electrode materials inside the battery to cause direct short circuit inside the battery, and the needle piercing pass rate is low. CONTENT OF THE UTILITY MODEL

[0004] To solve the above technical problems, the application provides a battery, a shell thereof and a battery module, which improve the safety of the battery, avoid internal short circuit of the battery and improve the needle piercing pass rate of the battery.

[0005] The technical scheme adopted by the application to solve the technical problems is as follows:

[0006] A battery shell, comprising an open-ended shell, the inner circumferential side wall of the shell is covered with a composite layer, the composite layer comprises an insulating layer and an adhesive layer connecting the insulating layer and the shell, the insulating layer has ductility, and the thickness of the composite layer is greater than or equal to 0.02 mm.

[0007] Preferably, the thickness of the adhesive layer is 0.005-0.05 mm.

[0008] Preferably, the thickness of the insulating layer is 0.005-0.05 mm.

[0009] Preferably, the shell comprises a shell body and a bottom plate arranged at the bottom of the shell body, the wall thickness of the shell body is 0.16-0.21 mm, and the thickness of the bottom plate is 0.2-0.4 mm.

[0010] Preferably, the material of the shell is stainless steel.

[0011] Preferably, the material of the adhesive layer is any one of polyurethane adhesive, polyacrylic resin adhesive, epoxy resin adhesive, organic silicon adhesive and rubber.

[0012] Preferably, the material of the insulating layer is any one of polypropylene, polyethylene, styrene-butadiene rubber, polyurethane, polytetrafluoroethylene and polyvinylidene fluoride.

[0013] A battery comprises:

[0014] The battery shell as described above;

[0015] A roll core is arranged in the battery shell, two ends of the roll core are respectively provided with a positive electrode lug and a negative electrode lug, and the negative electrode lug is connected to the bottom wall of the battery shell;

[0016] A cap is connected to the battery shell to cover the opening, and the positive electrode lug is connected to the cap.

[0017] Preferably, the two ends of the roll core are both provided with an insulating sheet, the insulating sheet at one end of the positive electrode lug is a first insulating sheet, the insulating sheet at one end of the negative electrode lug is a second insulating sheet, the positive electrode lug passes through the first insulating sheet to connect the cap, and the negative electrode lug passes through the second insulating sheet to connect the bottom wall of the shell.

[0018] A battery module comprises the battery as described above.

[0019] Compared with the prior art, the battery, the shell thereof, and the battery module of the embodiments of the present application have the beneficial effect that: by coating a composite layer on the inner circumferential side wall of the shell, the composite layer comprising an insulating layer and an adhesive layer connecting the insulating layer and the shell, the inner circumferential side wall of the shell is insulated, so that direct contact between the metal shell and the positive electrode lug of the battery is avoided to cause short circuit. At the same time, since the insulating layer has ductility and the thickness of the composite layer is greater than or equal to 0.02 mm, when the battery is punctured, the insulating layer will adhere to the surface of the steel needle to form an insulating protective layer, thereby avoiding direct short circuit of the battery caused by the needle tip conducting the positive and negative electrode materials, and improving the puncture passing rate of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a structural schematic diagram of the battery of the present application.

[0021] Figure 2 FIG. 2 is a structural schematic diagram of the battery shell of the present application. Figure 1 FIG. 3 is a partial enlarged view of A in FIG. 2.

[0022] Wherein: 1-shell, 11-shell body, 12-bottom plate, 13-opening, 2-composite layer, 21-insulating layer, 22-adhesive layer, 3-roll core, 4-positive electrode lug, 5-negative electrode lug, 6-cap, 7-first insulating sheet, 8-second insulating sheet. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application are described in further detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present application but are not used to limit the scope of the present application.

[0024] In this application, unless specifically defined otherwise, the terms "mounting", "connected", "connection", "fixed", and the like should be construed broadly and do not necessarily mean fixedly connected, but can be removably connected, or integral; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0025] As shown in Figures 1-2 A battery according to a preferred embodiment of the present application includes a battery shell, a roll core 3 and a cap 6, the battery shell includes a shell 1 with an open end 13, the inner circumferential side wall of the shell 1 is coated with a composite layer 2, the composite layer 2 includes an insulating layer 21 and an adhesive layer 22 connecting the insulating layer 21 and the shell 1, and the insulating layer 21 has ductility, the thickness of the composite layer 2 is greater than or equal to 0.02mm. The roll core 3 is arranged in the battery shell, the two ends of the roll core 3 are respectively provided with a positive electrode lug 4 and a negative electrode lug 5, and the negative electrode lug 5 is connected to the bottom wall of the battery shell; the cap 6 is connected to the battery shell to cover the opening 13, and the positive electrode lug 4 is connected to the cap 6.

[0026] Based on the above technical features of the battery, by coating the composite layer 2 on the inner circumferential side wall of the shell 1, the composite layer 2 includes an insulating layer 21 and an adhesive layer 22 connecting the insulating layer 21 and the shell 1, so that the inner circumferential side wall of the shell 1 is insulated, which can avoid the direct contact between the metal shell 1 and the positive electrode lug 4 of the battery, thereby preventing short circuit. At the same time, since the insulating layer 21 has ductility, and the thickness of the composite layer 2 is greater than or equal to 0.02mm, when the battery is punctured, the insulating layer 21 will adhere to the surface of the steel needle, forming an insulating protective layer, which can avoid the direct short circuit of the battery caused by the needle tip conducting the positive and negative electrode materials, thereby improving the puncture passing rate of the battery.

[0027] In the embodiment, the thickness of the adhesive layer 22 is 0.005-0.05mm, such as 0.01mm, 0.015mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, or any value or range between any two of the above values. The thickness of the insulating layer is 0.005-0.05mm, such as 0.01mm, 0.015mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, or any value or range between any two of the above values.

[0028] In the embodiment, the shell 1 comprises a shell body 11 and a bottom plate 12 arranged at the bottom of the shell body 11, and the composite layer 2 is coated on the shell body 11, so that the thickness of the composite layer 2 can be regarded as a part of the thickness of the shell body 11, and thus the thickness of the shell body 11 is smaller than the thickness of the bottom plate 12. Specifically, the wall thickness of the shell body 11 is 0.16-0.21 mm, such as 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, or any value or range between any two of the above values. The thickness of the bottom plate 12 is greater than the thickness of the shell body and is 0.2-0.4 mm, such as 0.22 mm, 0.25 mm, 0.27 mm, 0.29 mm, 0.3 mm, 0.32 mm, 0.35 mm, 0.38 mm, or any value or range between any two of the above values.

[0029] In the embodiment, the shell 1 is made of stainless steel, preferably nickel-plated stainless steel. The material of the adhesive layer 22 is any one or more of polyurethane adhesive, polyacrylic resin adhesive, epoxy resin adhesive, silicone adhesive, and rubber. The material of the insulating layer 21 is any one or more of polypropylene, polyethylene, styrene-butadiene rubber, polyurethane, polytetrafluoroethylene, and polyvinylidene fluoride, i.e., the composite layer 2 is a high polymer material. Since the composite layer 2 replaces a part of the thickness of the shell body 11, the amount of stainless steel used to make the shell body 11 can be reduced, and compared with stainless steel, the density of high polymer material is smaller, so that the weight of the battery can be reduced, and the cost is cheaper, which can further improve the energy density and manufacturing cost of the battery.

[0030] In the process of making the battery shell, the inside of the nickel-plated stainless steel is first coated with a polymer adhesive layer 22, and then coated with a polymer insulating layer 21, and the position of the bottom plate 12 of the shell 1 is reserved without coating (i.e., the reserved position is the bottom of the shell, and the size is the same as that of the bottom plate 12, with a diameter of 10-100 mm, which is reserved according to the actual situation), and then the stainless steel containing the polymer composite layer 2 is punched into a battery shell.

[0031] In the embodiment, to avoid the direct contact of the winding core 3 with the bottom wall of the battery shell or the cap 6 leading to the communication of the positive and negative poles of the winding core 3 and thus causing short circuit, the two ends of the winding core 3 are provided with insulating sheets, the insulating sheet at one end of the positive pole lug 4 is a first insulating sheet 7, the insulating sheet at one end of the negative pole lug 5 is a second insulating sheet 8, the positive pole lug 4 passes through the first insulating sheet 7 to be connected to the cap 6, and the negative pole lug 5 passes through the second insulating sheet 8 to be connected to the bottom wall of the shell 1. In the specific arrangement, the first insulating sheet 7 is provided with a through hole corresponding to the positive pole lug 4, and the second insulating sheet 8 is also provided with a through hole corresponding to the negative pole lug 5, so as to facilitate the positive pole lug 4 and the negative pole lug 5 to pass through the corresponding insulating sheets.

[0032] To illustrate the technical effects of the present application, the following specific examples and comparative examples are described.

[0033] Example One

[0034] The diameter of the winding core 3 is about 17.8 mm, the height of the winding core 3 is 61 mm, the inner diameter of the shell is 18.0 mm, and the wall thickness is 0.22 mm, which includes a 0.17 mm stainless steel layer and a 0.05 mm thick high polymer composite layer. The high polymer composite layer 2 is composed of a 0.01 mm polyurethane adhesive and a 0.04 mm polypropylene layer.

[0035] Example Two

[0036] The preparation method is consistent with that of Example One, except that the thickness of the shell body 11 is changed to 0.21 mm, and the high polymer composite layer 2 is composed of a 0.005 mm polyurethane adhesive layer and a 0.005 mm polypropylene layer.

[0037] Example Three

[0038] The preparation method is consistent with that of Example One, except that the thickness of the shell body 11 is changed to 0.2 mm, and the high polymer composite layer 2 is composed of a 0.005 mm polyurethane adhesive layer and a 0.015 mm polypropylene layer.

[0039] Example Four

[0040] The preparation method is consistent with that of Example One, except that the high polymer composite layer 2 is composed of a 0.04 mm polyurethane adhesive layer and a 0.01 mm polypropylene layer.

[0041] Example Five

[0042] The preparation method is consistent with that of Example One, except that the high polymer composite layer 2 is composed of a 0.02 mm epoxy resin adhesive layer and a 0.03 mm polyethylene insulating layer.

[0043] Comparative Example One

[0044] The steel shell is not provided with a polymer composite layer, and the wall thickness is 0.22 mm.

[0045] Performance test results

[0046] The batteries prepared in Examples 1-5 and Comparative Example 1 are subjected to the needle puncture test, and the results are as follows:

[0047]

[0048] It can be seen from the above examples that the needle puncture performance of the battery can be improved after the polymer composite layer 2 is added to the battery shell. It is further proved that only when the thickness of the polymer composite layer 2 is greater than or equal to 0.02 mm, the needle puncture risk can be significantly reduced.

[0049] To solve the above technical problems, the application also provides a battery module, which comprises a conductive connecting piece and the battery described above. The caps 6 of two adjacent batteries are connected by the conductive connecting piece to form series and parallel connection between the batteries. The battery module of the application can effectively avoid internal short circuit of the battery, has high safety, and can effectively improve the needle puncture passing rate of the battery.

[0050] The above is only the preferred embodiment of the application. It should be pointed out that for those skilled in the art, without departing from the technical principles of the application, a number of improvements and substitutions can be made, which should also be considered as the protection scope of the application.

Claims

1. A battery housing, characterized by: The battery shell comprises an open-ended shell, an inner circumferential side wall of the shell is coated with a composite layer, the composite layer comprises an insulating layer and a bonding layer connecting the insulating layer and the shell, and the insulating layer has ductility, and the thickness of the composite layer is greater than or equal to 0.02 mm.

2. The battery case of claim 1, wherein: The thickness of the bonding layer is 0.005-0.05 mm.

3. The battery case of claim 1, wherein: The thickness of the insulating layer is 0.005-0.05 mm.

4. The battery case of claim 1, wherein: The shell comprises a shell body and a bottom plate arranged at the bottom of the shell body, the wall thickness of the shell body is 0.16-0.21 mm, and the thickness of the bottom plate is 0.2-0.4 mm.

5. The battery case of claim 1, wherein: The shell is made of stainless steel.

6. The battery housing of any one of claims 1-5, wherein: The bonding layer is made of any one of polyurethane adhesive, polyacrylic resin adhesive, epoxy resin adhesive, organic silicon adhesive and rubber.

7. The battery housing of any one of claims 1-5, wherein: The insulating layer is made of any one of polypropylene, polyethylene, styrene butadiene rubber, polyurethane, polytetrafluoroethylene and polyvinylidene fluoride.

8. A battery, characterized by: The battery shell comprises: The battery shell according to any one of claims 1-7; A winding core arranged in the battery shell, two ends of the winding core are respectively provided with a positive electrode lug and a negative electrode lug, and the negative electrode lug is connected to the bottom wall of the battery shell; A cap connected to the battery shell to cover the opening, and the positive electrode lug is connected to the cap.

9. The battery of claim 8, wherein: Both ends of the winding core are provided with insulating sheets, the insulating sheet at one end of the positive electrode lug is a first insulating sheet, the insulating sheet at one end of the negative electrode lug is a second insulating sheet, the positive electrode lug passes through the first insulating sheet to be connected to the cap, and the negative electrode lug passes through the second insulating sheet to be connected to the bottom wall of the shell.

10. A battery module, characterized by The battery comprises the battery shell according to any one of claims 8-9.

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