Composite membrane structure, aluminum-plastic film, lithium battery and electronic equipment

Abstract

The utility model discloses a composite film structure, which comprises a polypropylene layer, an aluminum layer and a nylon layer stacked in sequence; wherein, a nano thermal insulation layer is provided at least between the polypropylene layer and the aluminum layer, or at least between the aluminum layer and the nylon layer. The utility model also discloses an aluminum-plastic film having the composite film structure, and a lithium battery and an electronic device using the aluminum-plastic film. The composite film structure provided by the utility model shares a part of the structure with the existing aluminum-plastic film, so in the process of preparing the aluminum-plastic film, the designated area of ​​the aluminum-plastic film can be constructed as the composite film structure of the utility model. When the aluminum-plastic film having the composite film structure of the utility model is used to prepare the shell of the lithium battery, in the process of encapsulating the wound battery core, the composite film structure area can be used as the contact part of the corner area. In this way, the heat generated during the charging process of the lithium battery is continuously accumulated in the corner area, the dynamic performance of the corner area is improved, and the risk of lithium deposition in the corner area can be improved.

Description

Technical Field

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

[0002] As the demand for fast charging rates of mobile phones increases, the charging rate of lithium batteries used in mobile phones is also increasing.

[0003] However, when the charging rate of the lithium battery is higher, the lithium deposition in the corner of the anode of the lithium battery is more serious. This is because the CB (Cell Balance) value of the corner area is smaller than the CB value of the straight area in the wound battery cell.

[0004] In view of this, it is indeed necessary to provide a technical solution to the above problems. Utility Model Content

[0005] The main purpose of the utility model is to propose a composite film structure that is compatible with aluminum-plastic film, aiming to improve the problem of lithium deposition in the corner area of ​​the wound battery core during the charging process of the lithium battery.

[0006] To achieve the above objectives, one aspect of the utility model provides a composite membrane structure, comprising a polypropylene layer, an aluminum layer and a nylon layer stacked in sequence; wherein a nano thermal insulation layer is provided at least between the polypropylene layer and the aluminum layer, or at least between the aluminum layer and the nylon layer.

[0007] In some embodiments, the nano thermal insulation layer is disposed between the polypropylene layer and the aluminum layer, and between the aluminum layer and the nylon layer.

[0008] In some embodiments, an adhesive layer is provided between a nano-insulation layer and the nylon layer, and between another nano-insulation layer and the polypropylene layer.

[0009] In some embodiments, the nano thermal insulation layer is one of a fumed silica layer, a nano aerogel layer, a nano ceramic layer, and a nano silicate gel layer.

[0010] In some embodiments, the nano thermal insulation layer is a fumed silica layer.

[0011] Another aspect of the present invention provides an aluminum-plastic film, a partial area of ​​which is the composite film structure as described above.

[0012] In some embodiments, the aluminum-plastic film has a preset area for configuring the wound battery cell, and a partial area is adjacent to two opposite sides of the preset area.

[0013] In some embodiments, the aluminum-plastic film has a groove for accommodating the wound battery cell, and a partial area is groove walls on two opposite sides of the groove.

[0014] Another aspect of the present invention provides a lithium battery, comprising: a shell made of the aluminum-plastic film as described above; a wound battery cell disposed in the shell; wherein a corner area of ​​the wound battery cell is in contact with the partial area.

[0015] Another aspect of the present invention provides an electronic device, which includes the lithium battery as described above.

[0016] The beneficial effects of the technical solution of the utility model are:

[0017] The composite film structure provided by the utility model shares some structures with the existing aluminum-plastic film, so in the process of preparing the aluminum-plastic film, the designated area of ​​the aluminum-plastic film can be constructed as the composite film structure of the utility model. When the aluminum-plastic film having the composite film structure of the utility model is used to prepare the shell of the lithium battery, in the process of encapsulating the wound battery cell, the composite film structure area can be used as the contact part of the corner area. At this time, since the composite film structure includes a nano-insulation layer, and the composite film structure only contacts the corner area of ​​the wound battery cell, the heat generated during the charging process of the lithium battery is continuously accumulated in the corner area, so that the temperature of the corner area is greater than the temperature of the straight area, thereby improving the dynamic performance of the corner area and improving the risk of lithium precipitation in the corner area. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the aluminum-plastic film of the prior art;

[0019] Figure 2 This is a schematic structural diagram of the composite membrane structure of Example 1 of the utility model;

[0020] Figure 3 This is a schematic structural diagram of the composite membrane structure of Example 2 of the utility model;

[0021] Figure 4 This is a schematic structural diagram of the composite membrane structure of Example 3 of the utility model;

[0022] Figure 5 A schematic structural diagram of an aluminum-plastic film according to Embodiment 4 of the present utility model;

[0023] Figure 6 This is another schematic structural diagram of the aluminum-plastic film of Example 4 of the utility model.

[0024] Description of Figure Numbers:

[0025] Composite membrane structure 100 ; polypropylene layer 110 ; aluminum layer 120 ; nylon layer 130 ; nano thermal insulation layer 140 ; ​​adhesive layer 150 ; preset area 200 ; groove 300 .

[0026] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the scheme in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, top, bottom, side...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0029] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0030] In addition, the descriptions involving "first", "second", etc. in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features.

[0031] Example 1

[0032] In view of the technical defects existing in the related art, this embodiment provides a composite membrane structure 100. Figure 2 As shown, the composite membrane structure 100 of this embodiment includes a polypropylene layer 110, an aluminum layer 120 and a nylon layer 130 stacked in sequence. A nano thermal insulation layer 140 is disposed between the polypropylene layer 110 and the aluminum layer 120.

[0033] Combination Figure 1 and Figure 2 As shown, the composite membrane structure 100 of this embodiment and the existing aluminum-plastic film both have a laminated polypropylene layer 110, an aluminum layer 120 and a nylon layer 130, so the composite membrane structure 100 of this embodiment can be formed in a designated area of ​​the aluminum-plastic film during the preparation of the aluminum-plastic film. For example, the preparation process of the conventional aluminum-plastic film is as follows:

[0034] Step 1: coating the aluminum layer 120 on two opposite sides to form an adhesive layer 150 .

[0035] Step 2: Bond the polypropylene layer 110 and the nylon layer 130 to opposite sides of the aluminum layer 120 .

[0036] The process of forming the composite film structure 100 of this embodiment in the designated area of ​​the aluminum-plastic film is as follows:

[0037] Step 10: forming a nano thermal insulation layer 140 in a designated area on one side of the aluminum layer 120 .

[0038] Step 20 : coating the aluminum layer 120 on two opposite sides to form an adhesive layer 150 .

[0039] Step 30 , the polypropylene layer 110 is bonded to one side of the aluminum layer 120 where the nano thermal insulation layer 140 is provided, and the nylon layer 130 is bonded to the other side.

[0040] As can be seen above, the composite film structure 100 of the present embodiment shares some structures with the existing aluminum-plastic film, so in the process of preparing the aluminum-plastic film, the designated area of ​​the aluminum-plastic film can be constructed as the composite film structure 100 of the present utility model. When the aluminum-plastic film having the composite film structure 100 of the present embodiment is used to prepare the shell of the lithium battery, in the process of encapsulating the wound battery cell, the composite film structure 100 area can be brought into contact with the specific area of ​​the wound battery cell, so that the heat generated during the charging process of the lithium battery is continuously accumulated in the specific area, thereby increasing the temperature of the specific area, which is conducive to improving the dynamic performance of the specific area of ​​the wound battery cell, and then improving the risk of lithium plating in the specific area.

[0041] Example 2

[0042] like Figure 3 As shown, the composite membrane structure 100 of this embodiment includes a polypropylene layer 110, an aluminum layer 120 and a nylon layer 130 stacked in sequence. Different from Example 1, the nano thermal insulation layer 140 of this embodiment is arranged between the nylon layer 130 and the aluminum layer 120. The preparation process of the composite membrane structure 100 of this embodiment is different from that of Example 1. For example, in step 30 of Example 1, the nylon layer 130 is bonded to one side of the aluminum layer 120 where the nano thermal insulation layer 140 is arranged, and the polypropylene layer 110 is bonded to the other side to obtain the composite membrane structure 100 of this embodiment. However, in terms of function, the composite membrane structure 100 of this embodiment is almost the same as the composite membrane structure 100 of Example 1.

[0043] Example 3

[0044] like Figure 4As shown, the composite membrane structure 100 of this embodiment includes a polypropylene layer 110, an aluminum layer 120 and a nylon layer 130 stacked in sequence. Different from Example 1 and Example 2, the nano thermal insulation layer 140 of this embodiment is arranged between the nylon layer 130 and the aluminum layer 120, and between the polypropylene layer 110 and the aluminum layer 120. The process of the composite membrane structure 100 of this embodiment is:

[0045] Step 100 : forming a nano thermal insulation layer 140 in a designated area on one side of the aluminum layer 120 , and forming another nano thermal insulation layer 140 in a designated area on the other side of the aluminum layer 120 .

[0046] Step 200 : coating the aluminum layer 120 on two opposite sides to form an adhesive layer 150 .

[0047] Step 300 : bonding the polypropylene layer 110 and the nylon layer 130 to opposite sides of the aluminum layer 120 .

[0048] Compared with Embodiment 1 and Embodiment 2, the composite membrane structure 100 of this embodiment has a double-layer nano thermal insulation layer 140, thereby having a better thermal insulation effect.

[0049] In some embodiments, the nano thermal insulation layer 140 uses a fumed silica layer. Since the particle size of fumed silica is very small, it has a large specific surface area, strong surface adsorption, large surface energy, high chemical purity, good dispersion performance, and good performance in thermal resistance and electrical resistance. Therefore, it is a good choice for the nano thermal insulation layer 140. The fumed silica layer is prepared by chemical vapor deposition (CAV), also known as thermal decomposition, dry method or combustion method. Its raw materials are generally silicon tetrachloride, oxygen (or air) and hydrogen, which react at high temperature. The reaction formula is: SiCl4+2H2+O2=SiO2+4HCl.

[0050] Among them, air and hydrogen are respectively pressurized, separated, cooled and dehydrated, dried with silica gel, and filtered for dust removal before being sent to the synthetic hydrolysis furnace. After the silicon tetrachloride raw material is sent to the distillation tower for distillation, it is heated and evaporated in the evaporator, and the dried and filtered air is used as a carrier to send it to the synthetic hydrolysis furnace. After silicon tetrachloride is gasified at high temperature (flame temperature 1000-1800°C), it is hydrolyzed in the gas phase with a certain amount of hydrogen and oxygen (or air) at a high temperature of about 1800°C; the fumed silica particles generated at this time are extremely fine and form aerosols with the gas, which are not easy to capture, so they are first aggregated into larger particles in the aggregator, and then collected by the cyclone separator, and then sent to the deacidification furnace, and the fumed silica is purged with nitrogen-containing air until the pH value is 4-6 to obtain the finished product.

[0051] In some optional examples, the preparation material of the nano thermal insulation layer 140 can be replaced by nano aerogel. Nano aerogel has extremely low density and thermal conductivity, as well as a very high surface area, and is often used in the preparation of thermal insulation materials. It can create a very small pore structure in the thermal insulation material, thereby reducing heat conduction, thereby ensuring the thermal insulation performance of the composite membrane structure 100.

[0052] In other optional examples, the preparation material of the nano thermal insulation layer 140 can also be replaced by nano porous materials, such as nano ceramic particles or nano silicate gel, etc. Nano porous materials are porous materials made of nano particles, have a very high surface area and internal pores, can produce small pore structures, block heat conduction, and improve thermal insulation performance, thereby ensuring the thermal insulation performance of the composite membrane structure 100.

[0053] Example 4

[0054] This embodiment provides an aluminum-plastic film. The aluminum-plastic film of this embodiment is used to form a shell of a lithium battery. The aluminum-plastic film of this embodiment has a polypropylene layer 110, an aluminum layer 120 and a nylon layer 130 stacked in sequence. Among them, a partial area of ​​the aluminum-plastic film is a composite film structure 100 as described in any one of embodiments 1 to 3.

[0055] Alternatively, if Figure 5 As shown, the aluminum-plastic film of this embodiment may have a preset area 200 for configuring a wound battery cell. Among them, a partial area of ​​the aluminum-plastic film constructed as a composite film structure 100 is adjacent to the opposite sides of the above-mentioned preset area 200. Therefore, when the aluminum-plastic film of this embodiment is used to prepare the shell of a lithium battery, in the process of encapsulating the wound battery cell, the area of ​​the composite film structure 100 can be used as the contact part of the corner area. At this time, since the composite film structure 100 includes a nano thermal insulation layer 140, and the composite film structure 100 is only in contact with the corner area of ​​the wound battery cell, the heat generated during the charging process of the lithium battery is continuously accumulated in the corner area, so that the temperature of the corner area is greater than the temperature of the straight area, thereby improving the dynamic performance of the corner area and improving the risk of lithium precipitation in the corner area.

[0056] Alternatively, if Figure 6 As shown, the aluminum-plastic film of this embodiment may have a groove 300 for accommodating a wound battery cell. The groove walls on opposite sides of the groove 300 are constructed as a composite film structure 100. When the aluminum-plastic film of this embodiment is used to prepare the shell of a lithium battery, the wound battery cell is placed in the groove 300 and the corner area of ​​the wound battery cell is in contact with the composite film structure 100, so that the heat generated during the charging process of the lithium battery is continuously accumulated in the corner area, so that the temperature of the corner area is greater than the temperature of the straight area, thereby improving the dynamic performance of the corner area and reducing the risk of lithium deposition in the corner area.

[0057] Example 5

[0058] The present embodiment provides a lithium battery, which includes a shell and a wound battery cell arranged in the shell. Among them, it is made of an aluminum-plastic film as provided in Example 4. The corner area of ​​the wound battery cell is in contact with the composite film structure area of ​​the aluminum-plastic film. Since the shell of the lithium battery has a composite film structure as described in any one of Examples 1 to 3, and the corner area of ​​the wound battery cell is in contact with the composite film structure area of ​​the aluminum-plastic film, the heat generated during the charging process of the lithium battery is continuously accumulated in the corner area, so that the temperature of the corner area is greater than the temperature of the straight area, thereby improving the dynamic performance of the corner area and improving the risk of lithium precipitation in the corner area.

[0059] Example 6

[0060] This embodiment provides an electronic device, which may be a smart phone, a smart watch, a tablet computer, or a laptop computer, but is not limited thereto. The electronic device includes the lithium battery described in Embodiment 5, so the possibility of lithium deposition inside the battery is lower than that of existing lithium batteries, thereby ensuring the stability and safety of the electronic device to a certain extent and improving the reliability of the electronic device.

[0061] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A composite membrane structure, characterized in that: It comprises a polypropylene layer, an aluminum layer and a nylon layer stacked in sequence; wherein a nano thermal insulation layer is provided at least between the polypropylene layer and the aluminum layer, or at least between the aluminum layer and the nylon layer.

2. The composite membrane structure according to claim 1, characterized in that: The nano thermal insulation layers are arranged between the polypropylene layer and the aluminum layer, and between the aluminum layer and the nylon layer.

3. The composite membrane structure according to claim 2, characterized in that: An adhesive layer is provided between one of the nano thermal insulation layers and the nylon layer, and between another of the nano thermal insulation layers and the polypropylene layer.

4. The composite membrane structure according to any one of claims 1 to 3, characterized in that: The nano thermal insulation layer is one of a fumed silicon dioxide layer, a nano aerogel layer, a nano ceramic layer, and a nano silicate gel layer.

5. The composite membrane structure according to claim 4, characterized in that: The nano thermal insulation layer is a gas phase silicon dioxide layer.

6. An aluminum-plastic film, characterized in that: A partial area of ​​the aluminum-plastic film is a composite film structure as claimed in any one of claims 1 to 5.

7. The aluminum-plastic film according to claim 6, characterized in that: The aluminum-plastic film has a preset area for configuring a wound battery core, and the partial area is adjacent to two opposite sides of the preset area.

8. The aluminum-plastic film according to claim 6, characterized in that: The aluminum-plastic film has a groove for accommodating the wound battery core, and the partial area is the groove walls on two opposite sides of the groove.

9. A lithium battery, characterized in that: include: A housing made of the aluminum-plastic film according to any one of claims 6 to 8; A wound battery cell is disposed in the housing; Wherein, the corner area of ​​the wound battery cell is in contact with the partial area.

10. An electronic device, characterized in that: Comprising the lithium battery as claimed in claim 9.

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