A high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles

Abstract

The application belongs to the field of supercapacitors, and more particularly relates to a high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles. The structure of the hybrid supercapacitor comprises a positive electrode sheet, a negative electrode sheet, a positive electrode tab, a negative electrode tab, a diaphragm and a container shell. The supercapacitor provided in the application is designed to be large in size, not only meeting the high energy requirement of the special vehicle, but also effectively solving the connection problem of the small-size hybrid supercapacitor, and meeting the high power and rapid charging requirement which cannot be met by the lithium ion battery.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of supercapacitors, and more particularly relates to a high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles. BACKGROUND

[0002] There are many types of supercapacitors, including solid-state supercapacitors and double-layer supercapacitors, but supercapacitors have the defects of low energy density, small capacity, and relatively small size. In high-power and high-energy application scenarios, high-energy lithium batteries cannot meet the working condition requirements, while supercapacitors have good rate performance and long service life, making them suitable for such application scenarios.

[0003] Macroscopic parameters usually have a direct impact on the electrochemical performance, thermal performance, safety, and service life performance of supercapacitors. These parameters include electrode base foils, active materials, separators, and electrode sizes and positions, which can change the energy density, capacity, rate performance, and service life of supercapacitors.

[0004] The present inventors have found that changing the macroscopic parameters of supercapacitors can improve the electrical performance of supercapacitors, making them more suitable for high-energy and high-power application scenarios.

[0005] In the prior art, supercapacitors are mostly double-layer supercapacitors and hybrid supercapacitors, but their sizes are usually medium or small, and their capacities are low, which cannot meet the requirements of long-term high-power charging and discharging and high-energy working conditions of vehicles such as mine trucks, buses, and ships. Therefore, the macroscopic parameters of hybrid supercapacitors are designed and modified to meet the corresponding requirements.

[0006] Therefore, to solve the above problems, the present application provides a high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles, which not only has an increased capacitor size, but also effectively overcomes the problems of existing capacitors. SUMMARY

[0007] To solve the above problems, the present application provides a high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles, which not only has an increased capacitor size, but also effectively overcomes the problems of existing capacitors.

[0008] As a preferred solution, the positive electrode sheet and the negative electrode sheet and the separator are stacked in the order of negative electrode sheet-separator-positive electrode sheet to form a battery base structure.

[0009] As a preferred scheme, the width of the positive and negative electrode pieces is 80-100 mm; the length of the positive electrode piece is 400-475 mm; the length of the negative electrode piece is 410-490 mm; and the thickness of the battery base formed by the positive and negative electrode pieces and the separator is 6-12 mm.

[0010] As a preferred scheme, the first connection end of the negative electrode piece end of the battery base is a negative electrode piece blank, and the end of the negative electrode tab is fixedly connected to the negative electrode piece blank; the positive electrode piece end of the battery base is a second connection end, and the second connection end is a positive electrode piece blank, and the end of the positive electrode tab is fixedly connected to the positive electrode piece blank.

[0011] As a preferred scheme, the length of the positive and negative electrode tabs is 50-80 mm, the width is 10-30 mm, and the thickness is 0.3-0.6 mm.

[0012] As a preferred scheme, the container shell is wrapped around the outside of the first and second connection ends in a nested manner, and the positive and negative electrode piece blanks are wrapped inside the container shell, and the positive and negative electrode tabs pass through the slits of the container shell and extend to the outside.

[0013] As a preferred scheme, the outer surface of the positive electrode tab is also coated with a heat dissipation coating; and the heat dissipation coating is an epoxy resin composite coating.

[0014] As a preferred scheme, the epoxy resin composite coating includes at least 5-50 wt% of nano-graphene.

[0015] As a preferred scheme, the epoxy resin composite coating includes, in parts by mass, the following raw materials: 80-120 parts of an epoxy modified composite emulsion, 10-50 parts of an acrylic resin, 50-300 parts of deionized water, 4-15 parts of a functional additive, and 30-80 parts of nano-graphene.

[0016] As a preferred scheme, the functional additive is a defoaming agent, a leveling agent, and an antioxidant.

[0017] As a preferred scheme, the defoaming agent is a silicone defoaming agent, and the antioxidant is at least one of the antioxidant 10 series products.

[0018] As a preferred scheme, the average particle size of the nano-graphene is 100-500 nm.

[0019] As a preferred scheme, the average particle size of the nano-graphene is 150-250 nm.

[0020] As a preferred scheme, the epoxy modified composite emulsion comprises the following components in parts by mass: methyl methacrylate 100 parts, BA 50 parts, EA 15 parts, dicyclopentenyl acrylate 3 parts, AEO 3 parts, sodium persulfate 1 part, acetone 80 parts, triethanolamine 1 part, and deionized water 500 parts.

[0021] Advantages:

[0022] 1. The application provides a high-capacity hybrid supercapacitor for a special vehicle with uniform heat distribution, which is designed to be large in size, thereby meeting the high energy requirement of the special vehicle, effectively solving the connection problem of a small-size hybrid supercapacitor, and meeting the high-power and rapid charging requirements that cannot be met by a lithium ion battery.

[0023] 2. The super-long supercapacitor provided by the application has large power, large rate and large charging and discharging current, and when the size of the supercapacitor is lengthened and the capacity is increased, the current under the same rate is increased, which causes obvious heat generation of the super-long single body, especially the heat generation near the positive electrode is increased, and the use of the special self-made heat dissipation coating in the application effectively avoids the phenomenon that the rapid and large heat generation at the positive electrode tab affects the performance of the supercapacitor due to the excessively large size of the supercapacitor.

[0024] 3. The super-long supercapacitor provided by the application effectively avoids the damage of the welding points of the positive and negative electrode tabs and the current collector blanking area to the container shell, thereby causing local thermal runaway, by increasing the self-supporting shell. At the same time, the R angle of the cell is protected, and the R angle damage and carbon drop in the preparation and circulation process of the large cell are effectively avoided, which also causes uneven heat generation and micro short circuit of the cell. The self-supporting shell also supports the container shell, so that the container shell is more flat, which is helpful to the uniform distribution of heat. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a structural schematic diagram of a supercapacitor single body obtained in Embodiment 1 of the application.

[0026] Figure 2 FIG. 2 is a structural schematic diagram of the positive and negative electrode tabs and the container shell of the supercapacitor single body obtained in Embodiment 1 of the application.

[0027] Figure 3 FIG. 3 is a schematic diagram of the heat field distribution of the supercapacitor obtained in Embodiment 1 of the application.

[0028] In the drawings:

[0029] 1-positive electrode tab, 2-negative electrode tab, 3-battery base body, 4-container shell. DETAILED DESCRIPTION

[0030] The application will be described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the protection scope of the application, and some non-essential improvements and adjustments made by the skilled in the art based on the content of the application still belong to the protection scope of the application.

[0031] Example 1

[0032] A high-capacity hybrid supercapacitor with uniform heat distribution for special vehicles, the structure of the hybrid supercapacitor comprising a positive electrode sheet, a negative electrode sheet, a positive electrode tab, a negative electrode tab, a separator and a container shell.

[0033] The positive electrode sheet and the negative electrode sheet and the separator are cyclically laminated in the order of negative electrode sheet-separator-positive electrode sheet to form a battery base structure.

[0034] The width of the positive electrode sheet and the negative electrode sheet is 95 mm; the length of the positive electrode sheet is 420 mm; the length of the negative electrode sheet is 435 mm; and the thickness of the battery base formed by the positive electrode sheet, the negative electrode sheet and the separator is 10 mm.

[0035] The negative electrode sheet end of the battery base is a first connecting end, and the negative electrode sheet blank is at the first connecting end; the positive electrode sheet end of the battery base is a second connecting end, and the positive electrode sheet blank is at the second connecting end; and the end of the negative electrode tab is fixedly connected with the negative electrode sheet blank, and the end of the positive electrode tab is fixedly connected with the positive electrode sheet blank.

[0036] The length of the positive electrode tab and the negative electrode tab is 60 mm, the width is 15 mm, and the thickness is 0.5 mm.

[0037] The self-supporting shell is wrapped outside the first connecting end and the second connecting end in a nested manner, the positive and negative electrode sheet blanks are wrapped inside the container shell, and the positive and negative electrode tabs pass through the slits of the container shell and extend to the outside.

[0038] The outer surface of the positive electrode tab is also coated with a heat dissipation coating; the heat dissipation coating is an epoxy resin composite coating, and the components include, by mass fraction: epoxy modified composite emulsion 85 parts, acrylic resin 15 parts, deionized water 200 parts, functional additives 9 parts, and nano-graphene 25 parts.

[0039] The functional additives are organic silicon defoaming agent 3 parts, leveling agent (Digo, TEGO Glide 100) 3 parts and antioxidant 1010 3 parts.

[0040] The average particle size of the nano-graphene is 200 nm.

[0041] The epoxy modified composite emulsion comprises the following components in parts by mass: methyl methacrylate 100 parts, BA 50 parts, EA 15 parts, dicyclopentenyl acrylate 3 parts, AEO 3 parts, sodium persulfate 1 part, acetone 80 parts, triethanolamine 1 part, and deionized water 500 parts.

[0042] The preparation method of the epoxy modified composite emulsion comprises the following steps: (1) mixing all raw materials except dicyclopentenyl acrylate, and stirring and reacting at 60°C for 3.5 hours; (2) then adding dicyclopentenyl acrylate, and continuing to react for 4.5 hours; and (3) finally neutralizing and emulsifying to obtain the epoxy modified composite emulsion.

[0043] Comparative Example 1

[0044] The specific implementation of the comparative example is the same as that of example 1, except that 15 parts of EA and 3 parts of dicyclopentenyl acrylate are not added in the epoxy modified composite emulsion.

[0045] Comparative Example 2

[0046] The specific implementation of the comparative example is the same as that of example 1, except that the nano graphene is 10 parts, and the average particle size of the nano graphene is 450 nm.

[0047] Comparative example 3

[0048] The specific implementation of the comparative example is the same as that of example 1, except that there is no self-supporting shell in the structure.

[0049] Performance evaluation

[0050] Super capacitor performance: charging to 4.2V at a current of 125A, discharging to 2.5V at a current of 125A, and testing the capacity of a single cell after 3 cycles, 5 samples are tested for each example and comparative example, and the average value of the measured values is recorded in table 1.

[0051] Heat dissipation performance: linear scanning test temperature field distribution is performed using an infrared thermal imager, 5 samples are tested for each example and comparative example, and the average value of the measured values is recorded in table 1.

[0052] AC internal resistance test: using an AC internal resistance meter, setting 1kHz gear, connecting the positive electrode pen to the positive electrode lug, and connecting the negative electrode pen to the negative electrode lug.

[0053] Table 1

[0054] Example Capacity / Wh Mean of monomer charge-discharge temperature distribution / °C AC internal resistance after end of charge Example 1 33.5 Wh 33.5℃ 0.40 mΩ Comparative Example 1 32.5 Wh 42.8℃ 0.37 mΩ Comparative Example 2 32.7 Wh 39.9℃ 0.39 mΩ Comparative Example 3 32.7 Wh 39.7℃ 0.39 mΩ

[0055] It can be seen from Examples 1-2, Comparative Examples 1-2 and Table 1 that the high-capacity hybrid supercapacitor for special vehicles with uniform heat distribution provided by the application has an overall size that is not designed in the prior art supercapacitor, so that it can be effectively applied to high-power-demand special vehicles or equipment such as mine cars, and meets the application conditions of long service life, high power and high energy. The improved capacitor size not only effectively reduces the material cost during monomer integration, but also further improves the capacity and generation efficiency of the monomer. By coating a specific heat dissipation coating on the positive electrode tab, the phenomenon of rapid and large heat generation at the positive electrode tab affecting the performance of the capacitor due to the oversize of the capacitor is effectively avoided. By increasing the self-supporting shell, the damage of the positive and negative electrode tabs and the current collector blank space welding points to the container shell is effectively avoided, thereby generating a local thermal runaway phenomenon. At the same time, the R angle of the cell is protected, effectively avoiding the damage of the R angle and the loss of carbon during the preparation and circulation of the large cell, which will also cause uneven heating and micro short circuit of the cell. The self-supporting shell also supports the container shell, making the container shell more flat, which is helpful for uniform heat distribution.

Claims

1. A high capacity hybrid supercapacitor for special vehicles with uniform heat distribution characterized in that: The structure of the hybrid supercapacitor comprises a positive electrode sheet, a negative electrode sheet, a positive electrode tab, a negative electrode tab, a diaphragm and a container shell; The width of the positive electrode sheet and the negative electrode sheet is 80-100 mm; the length of the positive electrode sheet is 400-475 mm; the length of the negative electrode sheet is 410-490 mm; the thickness of the battery base formed by the positive electrode sheet, the negative electrode sheet and the diaphragm is 6-12 mm; The outer surface of the positive electrode tab is further coated with a heat dissipation coating; the heat dissipation coating is an epoxy resin composite coating; The raw materials of the epoxy resin composite coating, by mass fraction, comprise: an epoxy modified composite emulsion 80-120 parts, an acrylic resin 10-50 parts, deionized water 50-300 parts, a functional additive 4-15 parts and nano graphene 30-80 parts; The epoxy modified composite emulsion comprises the following components by mass fraction: methyl methacrylate 100 parts, BA 50 parts, EA 15 parts, dicyclopentenyl acrylate 3 parts, AEO 3 parts, sodium persulfate 1 part, acetone 80 parts, triethanolamine 1 part and deionized water 500 parts.

2. The high power hybrid supercapacitor for special vehicles with uniform heat distribution according to claim 1, characterized in that: The positive electrode sheet and the negative electrode sheet and the diaphragm are cyclically laminated in the order of negative electrode sheet-diaphragm-positive electrode sheet to form a battery base structure.

3. The high power hybrid supercapacitor for special vehicles with uniform heat distribution as claimed in claim 1 wherein: The negative electrode sheet end of the battery base is a first connection end, and the first connection end is a negative electrode sheet blank area; the end of the negative electrode tab is fixedly connected to the negative electrode sheet blank area; the positive electrode sheet end of the battery base is a second connection end, and the second connection end is a positive electrode sheet blank area; the end of the positive electrode tab is fixedly connected to the positive electrode sheet blank area.

4. The high power hybrid supercapacitor for special vehicles with uniform heat distribution according to claim 3, characterized in that: The length of the positive electrode tab and the negative electrode tab is 50-80 mm, the width is 10-30 mm, and the thickness is 0.3-0.6 mm.

5. The high power hybrid supercapacitor for special vehicles with uniform heat distribution as claimed in claim 4 wherein: The container shell is embedded on the outside of the first connection end and the second connection end, and the positive electrode sheet blank area and the negative electrode sheet blank area are embedded in the container shell; the positive electrode tab and the negative electrode tab pass through the slits of the container shell and extend to the outside.

6. The high power hybrid supercapacitor for special vehicles with uniform heat distribution as claimed in claim 1 wherein: The average particle size of the nano graphene is 100-500 nm.

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