Pole piece, battery and electric device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a pole piece, which comprises a current collector and a tab connected with the current collector, a composite adhesive tape is arranged on one side of the current collector for accommodating the tab, the composite adhesive tape is coated on the tab, and the tab is coated on the surface of the current collector. The composite gummed paper comprises a bonding layer, a high-temperature-resistant layer and a flame-retardant layer which are sequentially stacked in the direction far away from the tab. According to the utility model, the flame-retardant layer is arranged, the flame-retardant layer falls off in the hot pressing process and can be adhered to the corresponding pole piece with the other polarity, and when the composite adhesive paper falls off, deforms and the like, the tab is in contact with the flame-retardant layer firstly, so that fire caused by direct contact between the tab and the pole piece with the other polarity is avoided, and the safety performance of the pole piece is improved. In addition, the utility model also discloses a battery and an electric device.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to a pole piece, a battery and an electrical device. Background Art

[0002] Nowadays, with the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium-ion batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, which provides a broad space for the application and development of lithium-ion batteries.

[0003] Among them, when the battery is subjected to a high-temperature external short-circuit test, the battery will be fully charged, and then the positive and negative tabs will be connected to a conductor with a resistance of 60-100mΩ, causing an external short circuit in the battery. Since the internal resistance of the battery is 10-30mΩ, the overall resistance is too small. According to Ohm's law, I=U / R, the battery will instantly release a current of more than 40A, and the tab is the confluence point. The tab of the battery will heat up severely, and the temperature will rise within a few seconds, causing the diaphragm and tab protective tape to melt, and the tab will be in direct contact with the current collector of the other polarity, causing a fire. For this reason, it is urgent to propose a new technical solution to solve the above problems. Utility Model Content

[0004] One of the purposes of the utility model is to provide a pole piece in view of the deficiencies of the prior art, which avoids fire caused by direct contact between the pole ear and the pole piece of another polarity by arranging a flame retardant layer on the composite adhesive paper, thereby improving the safety performance of the pole piece.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A pole piece comprises a current collector and a pole ear connected to the current collector, wherein a side of the current collector accommodating the pole ear is provided with a composite adhesive paper, the composite adhesive paper is coated on the pole ear, and the composite adhesive paper comprises an adhesive layer, a high temperature resistant layer and a flame retardant layer which are sequentially stacked in a direction away from the pole ear.

[0007] As an improvement of the utility model, the surface of the high temperature resistant layer in contact with the flame retardant layer is set to a smooth structure.

[0008] In practical applications, since the aluminum pole ear has a smaller specific heat capacity and a larger internal resistance than the copper-plated nickel pole ear, the heat generation heat and speed of the aluminum pole ear are better than those of the copper-plated nickel pole ear, so the pole piece is preferably a positive pole piece; due to the setting of the smooth structure, after the battery formed by the pole piece is hot-pressed, the flame-retardant layer is separated and pasted to the pole piece of the other polarity, so that when the pole piece is subjected to a short-circuit test, the pole ear heats up and causes the composite adhesive tape to deform and fall off, and the pole ear will not directly contact the pole piece of the other polarity, thereby avoiding the short circuit caused by direct connection between the positive and negative poles, thereby improving the safety of the pole piece.

[0009] As an improvement of the pole piece described in the utility model, when the pole ear is arranged at the end of the pole piece, the length of the composite adhesive paper in the width direction of the pole piece is the same as the width of the pole piece, the width of the composite adhesive paper in the length direction of the pole piece is greater than the width of the pole ear slot, and the width difference is preferably 5mm; when the pole ear is arranged in the middle of the pole piece, the length of the composite adhesive paper in the width direction is greater than the length of the pole ear slot, and the length difference is preferably 5mm, the width of the composite adhesive paper in the length direction of the pole piece is greater than the width of the pole ear slot, and the width difference is preferably 5mm; the above-mentioned setting of the size of the composite adhesive paper enables the composite adhesive paper to protect the pole ear without affecting the electrical performance of the pole piece.

[0010] As an improvement of the pole piece described in the utility model, the composite adhesive paper is provided with an extension portion toward the length direction of the pole ear, and the extension portion is the portion of the composite adhesive paper that exceeds the current collector in the width direction. The height H of the extension portion is 0.5mm-3mm, which prevents the pole ear from contacting the edge of the pole piece of the other polarity, thereby further improving the safety of the pole piece.

[0011] As an improvement of the pole piece described in the utility model, the flame retardant layer includes a flame retardant material layer and an adhesive material layer stacked together, the flame retardant material layer is connected to the high temperature resistant layer through the adhesive material layer, the mass of the flame retardant material layer is Z1, the mass of the adhesive material layer is Z2, and Z1 and Z2 satisfy the relationship: Z1:Z2=0.90-0.98:0.02-0.10.

[0012] Among them, the flame retardant material layer is one of inorganic flame retardants such as alumina trihydrate, titanium dioxide, magnesium hydroxide, hydrated zinc borate, etc., preferably alumina trihydrate, and the bonding material layer is one of organic polymer bonding agents such as polyvinylidene fluoride, styrene-butadiene rubber, carboxylated polyvinylidene fluoride, polyacrylic acid, etc., preferably polyvinylidene fluoride; the Z1 and Z2 satisfy the optimal relationship: Z1:Z2=0.96:0.04.

[0013] As an improvement of the pole piece of the utility model, the thickness of the flame retardant layer is 3 μm-20 μm, preferably 5 μm.

[0014] Wherein, the material of the high temperature resistant layer is polyimide or polytetrafluoroethylene.

[0015] As an improvement of the pole piece described in the utility model, the thickness of the high temperature resistant layer is 6 μm-20 μm, preferably 8 μm.

[0016] As an improvement of the pole piece described in the utility model, the melting point of the high temperature resistant layer is greater than or equal to 200°C.

[0017] Wherein, the material of the bonding layer is one of silicone glue, polyurethane glue and fluororubber, preferably silicone glue.

[0018] As an improvement of the pole piece described in the utility model, the thickness of the bonding layer is 2 μm-10 μm, preferably 3 μm.

[0019] As an improvement of the pole piece described in the utility model, the melting point of the bonding layer is greater than or equal to 200°C, preferably 220°C.

[0020] The second purpose of the utility model is to provide a battery, comprising the pole piece as described above.

[0021] The third object of the present utility model is to provide an electrical device comprising the battery as described above.

[0022] The beneficial effect of the utility model is that the pole piece of the utility model includes a current collector and a pole ear connected to the current collector, and a composite adhesive paper is pasted on one side of the current collector accommodating the pole ear, and the composite adhesive paper is coated on the pole ear, and the composite adhesive paper includes an adhesive layer, a high temperature resistant layer and a flame retardant layer stacked in sequence in a direction away from the pole ear. After the battery formed by the pole piece in the utility model is hot pressed, the flame retardant layer is separated and pasted on the pole piece of the other polarity, so that when the pole piece is short-circuited, the pole ear heats up and causes the composite adhesive paper to deform and fall off, and the pole ear will not directly contact the pole piece of the other polarity, thereby avoiding the situation where the positive and negative poles are directly connected to cause a short circuit, thereby improving the safety of the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0024] Figure 1 This is one of the structural schematic diagrams of the utility model.

[0025] Figure 2 This is the second structural schematic diagram of the present utility model.

[0026] Figure 3 It is a schematic diagram of the structure of the tab and the composite adhesive tape in the utility model.

[0027] Figure 4 It is a schematic diagram of the structure of the flame retardant layer in the utility model.

[0028] The reference numerals are described as follows:

[0029] 1-High temperature resistant layer;

[0030] 2- Adhesive layer;

[0031] 3-flame retardant layer; 31-flame retardant material layer; 32-adhesive material layer;

[0032] 100-current collector; 200-active material layer; 300-ear; 400-ear glue; 500-composite adhesive paper; 501-extension part;

[0033] W-width direction; L-length direction. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] Reference to "embodiment" in this application means that a particular feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0039] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0040] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0041] With the continuous improvement of the fast charging performance of mobile phone batteries, in order to increase the charging rate, the internal resistance of lithium-ion batteries is getting lower and lower, and the technology of centering the ear is used at the same time. However, this also brings a hidden danger. The 57°C high temperature external short circuit of the new national standard will cause fire and failure. This test is a mandatory item of the national standard. Now many manufacturers are increasing the thickness of the ear and using safer diaphragms to improve the pass rate. Thickening the ear will cause appearance problems, reduce the battery energy density, increase the difficulty of processing, and affect the cycle performance. The safer diaphragm also brings a significant increase in cost. In view of this, this embodiment avoids the fire caused by direct contact between the ear and the pole piece of the other polarity by setting a flame retardant layer, thereby solving the above problems.

[0042] The following is combined with Figures 1 to 4 The utility model is further described in detail with specific implementation modes, but is not intended to limit the utility model.

[0043] A pole piece comprises a current collector 100, an active material layer 200 coated on the current collector 100, and a pole piece 300 connected to the current collector 100 via a pole piece glue 400, a composite adhesive paper 500 being pasted on one side of the pole piece 300 away from the current collector 100, the composite adhesive paper 500 comprising an adhesive layer 2, a high temperature resistant layer 1 and a flame retardant layer 3 stacked in sequence in a direction away from the pole piece 300, a side of the high temperature resistant layer 1 in contact with the flame retardant layer 3 being arranged as a smooth structure, after the battery formed by the pole piece in this embodiment is hot pressed, the flame retardant layer 3 is separated and pasted onto a pole piece of another polarity, the smooth structure being arranged so that the flame retardant layer 3 can be more easily separated from the high temperature resistant layer 1 after hot pressing, so that when the pole piece is subjected to a short circuit test, the pole piece 300 is heated to cause the composite adhesive paper 500 to deform and fall off, and the pole piece 300 will not directly contact the pole piece of another polarity, thereby avoiding the situation where the positive and negative poles are directly connected to cause a short circuit, thereby improving the safety of the pole piece.

[0044] Specifically, the flame retardant layer 3 includes a flame retardant material layer 31 and an adhesive material layer 32 which are stacked. The flame retardant material layer 31 is connected to the high temperature resistant layer 1 through the adhesive material layer 32. The mass of the flame retardant material layer 31 is Z1, and the mass of the adhesive material layer 32 is Z2. Z1 and Z2 satisfy the relationship: Z1: Z2 = 0.90-0.98: 0.02-0.10. The flame retardant material layer 31 is one of inorganic flame retardants such as alumina trihydrate, titanium dioxide, magnesium hydroxide, and hydrated zinc borate. Preferably, it is alumina trihydrate, and the bonding material layer 32 is one of the organic polymer bonding agents such as polyvinylidene fluoride, styrene-butadiene rubber, carboxylated polyvinylidene fluoride, polyacrylic acid, etc., preferably polyvinylidene fluoride, and Z1 and Z2 satisfy the optimal relationship: Z1:Z2=0.96:0.04; the setting of the structure of the above-mentioned flame retardant layer 3 and the range of the mass ratio of the flame retardant material layer 31 and the bonding material layer 32 enable the flame retardant layer 3 to play a flame retardant role while being able to be separated from the high temperature resistant layer 1 after hot pressing.

[0045] Specifically, when the pole ear 300 is arranged at the end of the pole piece, as Figure 1 As shown, the length of the composite adhesive paper 500 in the width direction W is the same as the width of the electrode piece, and the width of the composite adhesive paper 500 in the length direction L is greater than the width of the electrode tab slot, and the width difference is preferably 5mm. In this embodiment, the width of the composite adhesive paper 500 is set to 12mm; when the electrode tab 300 is set in the middle of the electrode piece, as shown in FIG. Figure 2As shown, the length of the composite adhesive paper 500 in the width direction W is greater than the length of the pole tab slot, and the length difference is preferably 5 mm. In the present embodiment, the width of the composite adhesive paper 500 is set to 26 mm. The width of the composite adhesive paper 500 in the length direction L is greater than the width of the pole tab slot, and the width difference is preferably 5 mm. In the present embodiment, the width of the composite adhesive paper 500 is set to 20 mm. The above-mentioned size setting of the composite adhesive paper 500 enables the composite adhesive paper 500 to protect the pole tab 300 without affecting the electrical performance of the pole piece.

[0046] Specifically, the thickness of the flame retardant layer 3 is 3μm-20μm. It should be noted that when the thickness of the flame retardant layer 3 is in the range of 3μm-8μm, it is preferably 5μm. At this time, the thickness of the composite adhesive paper 500 is less than 20μm, which can prevent the possibility of reducing the electrode short circuit in the short circuit test without affecting the battery volume energy density; when the thickness of the flame retardant layer 3 is 8μm-20μm, it can further increase the safety performance of the electrode in the short circuit test, but due to the thickness, it will affect the volume energy density of the battery.

[0047] Specifically, the material of the high temperature resistant layer 1 is polyimide or polytetrafluoroethylene, the thickness of the high temperature resistant layer 1 is 6 μm-20 μm, preferably 8 μm; the melting point of the high temperature resistant layer 1 is greater than or equal to 200°C.

[0048] Specifically, the material of the bonding layer 2 is one of silicone, polyurethane glue and fluororubber, preferably silicone glue; the thickness of the bonding layer 2 is 2μm-10μm, preferably 3μm; the melting point of the bonding layer 2 is greater than or equal to 200°C, preferably 220°C.

[0049] In this embodiment, the thickness and material parameter settings of the composite adhesive tape 500 can enhance the protective effect, effectively improve the pass rate of high-temperature external short circuits, and reduce the risk of fire without affecting the energy density of the battery cell formed by the pole piece.

[0050] Specifically, the composite adhesive paper 500 is provided with an extension portion 501 in the length direction toward the pole ear 300, and the extension portion 501 is the portion of the composite adhesive paper 500 that exceeds the current collector 100 in the width direction W of the pole piece. The height H of the extension portion 501 is 0.5mm-1mm, 1mm-1.5mm, 1.5mm-2mm, 2mm-2.5mm, 2.5mm-3mm, which prevents the pole ear 300 from contacting the edge of the pole piece of the other polarity, thereby further improving the safety of the pole piece.

[0051] In order to better illustrate the above beneficial effects, the following embodiments and comparative examples are provided, wherein the parameters of the composite adhesive tape 500 in the embodiments and comparative examples are as shown in Table 1, the adhesive tape in the embodiments and comparative examples is pasted on the positive electrode ear, and a battery is made according to the prior art under the condition that other conditions are the same, and then the above battery is sent for 57°C high-temperature external short circuit testing according to different short-circuit resistance values, and the different short-circuit resistance values ​​and test results are shown in Table 2.

[0052] Table 1

[0053]

[0054]

[0055] Table 2

[0056] Group 40mΩ 50mΩ 60mΩ Comparative Example 1 0 / 10pass 0 / 10pass 2 / 10pass Comparative Example 2 0 / 10pass 2 / 10pass 3 / 10pass Comparative Example 3 2 / 10pass 3 / 10pass 6 / 10pass Example 1 5 / 10pass 7 / 10pass 8 / 10pass Example 2 8 / 10pass 10 / 10pass 10 / 10pass Example 3 9 / 10pass 10 / 10pass 10 / 10pass Example 4 10 / 10pass 10 / 10pass 10 / 10pass Example 5 10 / 10pass 10 / 10pass 10 / 10pass Example 6 10 / 10pass 10 / 10pass 10 / 10pass

[0057] According to the data in the above table, in the existing safety standards, it is only necessary to meet the safety performance of the 60mΩ external circuit. The data of the example in this implementation method is better than the data of the comparative example, which can illustrate that the battery made of the electrode with the flame retardant layer 3 can achieve better results in the actual high-temperature external short-circuit test than the conventional battery.

[0058] Battery

[0059] A battery comprises the pole piece as described above, and the battery may be a lithium ion battery, a sodium ion battery, a magnesium ion battery, etc.

[0060] Electrical devices

[0061] An electrical device, comprising a battery as described above, wherein the electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0062] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A pole piece, comprising a current collector (100) and a pole ear (300) connected to the current collector (100), characterized in that: A composite adhesive paper (500) is provided on one side of the current collector (100) that accommodates the pole lug (300), and the composite adhesive paper (500) is adhered to the pole lug (300). The composite adhesive paper (500) includes an adhesive layer (2), a high temperature resistant layer (1), and a flame retardant layer (3) that are sequentially stacked in a thickness direction away from the pole lug (300).

2. The pole piece according to claim 1, characterized in that: The surface of the high temperature resistant layer (1) in contact with the flame retardant layer (3) is configured as a smooth structure.

3. The pole piece according to claim 1, characterized in that: The composite adhesive paper (500) is provided with an extension portion (501) in the length direction of the pole ear, and the extension portion (501) is the portion of the composite adhesive paper (500) that exceeds the current collector (100) in the width direction (W) of the pole piece, and the height H of the extension portion (501) is 0.5 mm-3 mm.

4. The pole piece according to claim 1, characterized in that: The flame retardant layer (3) comprises a flame retardant material layer (31) and an adhesive material layer (32) which are stacked, and the flame retardant material layer (31) is connected to the high temperature resistant layer (1) via the adhesive material layer (32).

5. The pole piece according to claim 1, characterized in that: The melting points of the bonding layer (2) and the high temperature resistant layer (1) are both greater than or equal to 200°C.

6. The pole piece according to claim 1, characterized in that: The thickness of the flame retardant layer (3) is 3 μm-20 μm.

7. The pole piece according to claim 1, characterized in that: The thickness of the high temperature resistant layer (1) is 6 μm-20 μm.

8. The pole piece according to claim 1, characterized in that: The thickness of the bonding layer (2) is 2 μm-10 μm.

9. A battery, characterized in that: Comprising a pole piece as described in any one of claims 1 to 8.

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

Images