KR102754109B1 - Electrode for electrical double layer capacitor with improved high temperature life property and manufacturing method thereof and electrical double layer capacitor including the same - Google Patents

Abstract

Disclosed are an electrode for an electric double layer capacitor with improved high-temperature life characteristics, a method for manufacturing the same, and an electric double layer capacitor including the same, for improving the life characteristics of an electrode for an electric double layer capacitor that deteriorates at high temperatures.
An electrode for an electric double layer capacitor with improved high-temperature life characteristics according to the present invention comprises: an electrode current collector; and an electrode active material layer formed on at least one surface of the electrode current collector; wherein the electrode active material layer is characterized by including activated carbon, a conductive material, a binder, and dimethyl siloxane.

Description

Electrode for electric double layer capacitor with improved high temperature life property and manufacturing method thereof and electric double layer capacitor including the same {ELECTRODE FOR ELECTRICAL DOUBLE LAYER CAPACITOR WITH IMPROVED HIGH TEMPERATURE LIFE PROPERTY AND MANUFACTURING METHOD THEREOF AND ELECTRICAL DOUBLE LAYER CAPACITOR INCLUDING THE SAME}

The present invention relates to an electrode for an electric double layer capacitor with improved high-temperature life characteristics, a method for manufacturing the same, and an electric double layer capacitor comprising the same. More specifically, the present invention relates to an electrode for an electric double layer capacitor with improved high-temperature life characteristics for improving the life characteristics of an electrode for an electric double layer capacitor that deteriorates at high temperatures, a method for manufacturing the same, and an electric double layer capacitor comprising the same.

An electric double layer capacitor (EDLC) is an energy storage medium that uses a pair of charge layers (electric double layers) with different signs on opposite surfaces of a positive electrode and a negative electrode with a separator in between, making it a device that can be continuously charged and discharged.

These electric double layer capacitors are mainly used as auxiliary power supplies for various electric and electronic devices, IC backup power supplies, etc. Recently, electric double layer capacitors have been widely applied to toys, industrial power supplies, UPS (Uninterrupted Power Supply), solar energy storage, HEV/EV SUB power supplies, etc.

Recently, various studies have been conducted to reduce the internal resistance and improve the high-temperature characteristics of electric double layer capacitors.

However, the reality is that electric double layer capacitors, even though they have achieved reduced internal resistance and improved high-temperature characteristics, cannot achieve satisfactory performance when used at high voltages of approximately 2.7 V or higher or high-temperature stability of approximately 85°C or higher.

Therefore, efforts are underway to develop electric double layer capacitors designed to have improved life characteristics even at high temperatures.

Related prior art literature includes Korean Patent Publication No. 10-2020-0053180 (published on May 18, 2020), which describes an electrode including a conductive layer containing a corrosion-inhibiting additive, a method for manufacturing the same, and a supercapacitor using the same.

The purpose of the present invention is to provide an electrode for an electric double layer capacitor having improved high-temperature life characteristics and a method for manufacturing the same, and an electric double layer capacitor including the same, for improving the life characteristics of an electrode for an electric double layer capacitor that deteriorates at high temperatures.

According to an embodiment of the present invention for achieving the above object, an electrode for an electric double layer capacitor with improved high-temperature life characteristics includes: an electrode current collector; and an electrode active material layer formed on at least one surface of the electrode current collector; wherein the electrode active material layer is characterized by including activated carbon, a conductive material, a binder, and dimethyl siloxane.

The electrode active material layer comprises 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 1 to 5 wt% of the dimethyl siloxane.

The activated carbon used above has a surface area of 1,800 to 2,500 m2/g, and the electrode has a thickness of 140 to 200 μm.

In order to achieve the above object, a method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention comprises the steps of: (a) mixing activated carbon and a conductive material; (b) adding a binder, dimethyl siloxane, and a dispersion medium to the mixed electrode material and stirring to form an electrode active material slurry; (c) applying the electrode active material slurry to an electrode current collector; and (d) rolling and drying the electrode current collector to which the electrode active material slurry is applied to form an electrode active material layer.

After the step (d), the electrode active material layer includes 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 1 to 5 wt% of the dimethyl siloxane.

According to an embodiment of the present invention for achieving the above object, an electric double layer capacitor including an electrode for an electric double layer capacitor with improved high-temperature life characteristics comprises: a case impregnated with an electrolyte inside; a header covering an upper side of the case; and a winding element inserted inside the case and in which a cathode, a separator, and a cathode are sequentially laminated and wound; wherein each of the cathode and the anode includes an electrode current collector and an electrode active material layer formed on at least one surface of the electrode current collector, and the electrode active material layer is characterized in that it includes activated carbon, a conductive material, a binder, and dimethyl siloxane.

The electrode active material layer comprises 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 1 to 5 wt% of the dimethyl siloxane.

An electrode for an electric double layer capacitor with improved high-temperature life characteristics according to the present invention, a method for manufacturing the same, and an electric double layer capacitor including the same are formed by applying an electrode active material slurry containing dimethyl siloxane in a strictly limited content ratio of 1 to 5 wt% to an electrode current collector, a conductive material, and a binder, and pressing and drying the slurry to form an electrode, which is then used as a positive electrode and a negative electrode.

Therefore, when voltage is applied to the negative and positive electrodes including electrode active material layers to which dimethyl siloxane is added and the high-temperature life characteristics of the electrode for an electric double layer capacitor and the manufacturing method thereof and the electric double layer capacitor including the same according to the present invention are subjected to high-temperature characteristics, excellent bonding strength, heat resistance and weather resistance are secured through the siloxane bond between dimethyl siloxane and the electrode material, thereby suppressing deterioration characteristics due to high temperature and high voltage.

As a result, the electrode for an electric double layer capacitor with improved high-temperature life characteristics according to the present invention, the method for manufacturing the same, and the electric double layer capacitor including the same can improve the life characteristics of the electrode for an electric double layer capacitor that deteriorates at high temperatures, thereby improving the high-temperature life characteristics of the electric double layer capacitor.

FIG. 1 is a front view showing an electric double layer capacitor including an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention.
Figure 2 is an exploded perspective view showing an enlarged view of the winding element of Figure 1.
Fig. 3 is a cross-sectional view of the joint taken along line Ⅲ-Ⅲ' of Fig. 2.
Figure 4 is a process flow diagram showing a method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention.
Figure 5 is a graph showing the results of calculating the change rate of the series equivalent resistance (ESR) for an electric double layer capacitor according to Examples 1 to 3 and Comparative Example 1.
Figure 6 is a graph showing the results of measuring the high temperature load capacity change rate for an electric double layer capacitor according to Examples 1 to 3 and Comparative Example 1.

The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and the present embodiments are provided only to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, with reference to the attached drawings, an electrode for an electric double layer capacitor with improved high-temperature life characteristics and a method for manufacturing the same and an electric double layer capacitor including the same according to a preferred embodiment of the present invention will be described in detail.

FIG. 1 is a front view showing an electric double layer capacitor including an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing an enlarged view of the winding element of FIG. 1.

Referring to FIGS. 1 and 2, an electric double layer capacitor (100) including an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention includes a case (110), a header (not shown), and a winding element (120). In addition, the electric double layer capacitor (100) including an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention may further include a first lead wire (142), a second lead wire (144), and a sealing rubber (130).

The case (110) has an open top and is impregnated with an electrolyte inside. At this time, the case (110) may have a cylindrical shape with an open top, or may be designed as a square shape such as a rectangular parallelepiped or a hexagonal column. The material of the case (110) may be stainless steel (SUS), but is not limited thereto.

The header is joined to the outer surface of the case (110) and covers the upper side of the case (110). At this time, the header can be joined to the case (110) by point welding, laser welding, or the like.

The winding element (120) is inserted into the inside of the case (110). This winding element (120) may be of a cylindrical type, but is not limited thereto. That is, the winding element (120) may be applied in various forms such as a laminate type and a coin type. Therefore, the winding element (120) is not particularly limited in its shape, and may have a coiled structure as illustrated, or may have a laminated structure.

This winding element (120) has a cathode (122), an anode (124), and a separator (126). At this time, the winding element (120) can be manufactured by winding the cathode (122), the separator (126), and the anode (124) with a winder to form a roll, and then attaching an adhesive tape (not shown) or the like around the roll.

The first and second lead wires (142, 144) are connected to the cathode (122) and the anode (124) of the winding element (120), electrically connecting the winding element (120) to the case (110) and the header.

These first and second lead wires (142, 144) may be made of a material such as a metal with excellent electrical conductivity or an alloy containing the metal. For this purpose, it is preferable that each of the first and second lead wires (142, 144) be formed of at least one material selected from among aluminum, iron, nickel, copper, stainless steel, and titanium.

The sealing rubber (130) is attached to the upper side of the case (110) to seal the interior of the case (110). This sealing rubber (130) is attached to the first and second lead wires (142, 144) in a fitting manner to seal the case (110) in order to prevent leakage of the electrolyte inside the case (110).

The separator (126) prevents the negative electrode (122) and the positive electrode (124) from physically contacting each other. In addition, the separator (126) is preferably porous and maintains an electrolyte within the pores to form a conductive path between the negative electrode (122) and the positive electrode (124). The material of the separator (126) is not particularly limited and may be selected from, for example, porous cellulose, polypropylene, polyethylene, fluorine-based resin, and the like.

Meanwhile, Fig. 3 is a cross-sectional view of the joint taken along line Ⅲ-Ⅲ' of Fig. 2, and will be explained in conjunction with Fig. 2.

As shown in FIGS. 2 and 3, the negative electrode (122) of the winding element (120) includes a negative electrode current collector (122a) and a negative electrode active material layer (122b) formed on at least one surface of the negative electrode current collector (122a), and the positive electrode (124) includes a positive electrode current collector (124a) and a positive electrode active material layer (124b) formed on at least one surface of the positive electrode current collector (124a).

Here, it is preferable that each of the cathode (122) and the anode (124) of the winding element (120) have a thickness of 140 to 200 μm.

In Fig. 3, the negative electrode active material layer (122b) and the positive electrode active material layer (124b) are respectively arranged on both sides of the negative electrode current collector (122a) and the positive electrode current collector (124a), but this is not necessarily limited thereto. For example, the negative electrode and positive electrode active material layers (122b, 124b) may be arranged on only one side of the negative electrode and positive electrode current collectors (122a, 124a).

In this way, each of the negative electrode (122) and the positive electrode (124) of the winding element (120) includes an electrode current collector (122a, 124a) and an electrode active material layer (122b, 124b) formed on at least one surface of the electrode current collector (122a, 124a).

The electrode current collector (122a, 124a) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may be selected from the group consisting of copper, aluminum, stainless steel, zinc, titanium, silver, palladium, nickel, iron, chromium, alloys thereof, and combinations thereof.

The electrode active material layer (122b, 124b) includes activated carbon, a conductive material, a binder, and dimethyl siloxane.

More specifically, the electrode active material layer (122b, 124b) includes 85 to 97 wt% of activated carbon, 1 to 10 wt% of conductive material, 1 to 10 wt% of binder, and 1 to 5 wt% of dimethyl siloxane.

Here, activated carbon may be one or more selected from hard wood, palm, coconut, petroleum pitch, and phenol. It is preferable to use activated carbon having a high specific surface area of 1,800 to 2,500 m2/g.

The conductive material is not particularly limited as long as it is an electronically conductive material that does not cause a chemical change, and examples thereof include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, Super-P, carbon fiber, and metal powders or metal fibers such as copper, nickel, aluminum, and silver.

In addition, it is preferable that the binder uses a heterogeneous binder. Specifically, it is preferable that the binder uses a binder in which polytetrafluoroethylene (PTFE), a rubber-based resin, and an acrylic resin are added together. In addition, as a secondary binder of the binder, it may further include at least one selected from a cellulose-based resin, a fluorine-based resin including polyvinylidene fluoride (PVDF), a thermoplastic resin including polyimide, polyamideimide, polyedylene (PE), and polypropylene (PP), and carboxymethyl cellulose (CMC) and mixtures thereof.

It is preferable that such binder is added in a content ratio of 1 to 10 wt% of the total weight of the electrode active material layer (122b, 124b). If the amount of binder added is less than 1 wt%, the bonding force between the electrode material and the current collector may be weak, causing a problem of breakage. On the other hand, if the amount of binder added exceeds 10 wt%, there is a high risk that the electrical conductivity may be reduced due to excessive use of the binder.

Dimethyl siloxane is added to the electrode active material layer (122b, 124b) and uniformly distributed on the surface of the electrode active material layer. When voltage is applied to the negative electrode (122) and positive electrode (124) including the electrode active material layer (122b, 124b) to which the dimethyl siloxane is added and high temperature characteristics are applied, excellent bonding force, heat resistance, and weather resistance are secured through the siloxane bond between the dimethyl siloxane and the electrode material, thereby suppressing the deterioration characteristics due to high temperature and high voltage. Accordingly, the present invention can provide an electrode for an electric double layer capacitor (EDLC) with improved high temperature lifespan compared to an electric double layer capacitor (EDLC) that relies only on the characteristics of activated carbon.

To this end, dimethyl siloxane is preferably added in a content ratio of 1 to 5 wt% of the total weight of the electrode active material layer (122b, 124b), and a more preferable range is 3 to 5 wt%. If the amount of dimethyl siloxane added is less than 1 wt%, it is difficult to properly exhibit the effects of improving the bonding strength, heat resistance, and weather resistance. On the other hand, if the amount of dimethyl siloxane added exceeds 5 wt%, the series equivalent resistance change rate (ESR) characteristics deteriorate, which is not preferable.

An electrode for an electric double layer capacitor with improved high-temperature life characteristics according to the above-described embodiment of the present invention and an electric double layer capacitor including the same are formed by applying an electrode active material slurry containing dimethyl siloxane in a strictly limited content ratio of 1 to 5 wt% to an electrode current collector, a conductive material, and a binder, and pressing and drying the electrode, and using the electrode as a positive electrode and a negative electrode.

Therefore, when voltage is applied to the negative and positive electrodes including electrode active material layers to which dimethyl siloxane is added and the electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention and is subjected to high-temperature characteristics, excellent bonding strength, heat resistance, and weather resistance are secured through the siloxane bond between dimethyl siloxane and the electrode material, thereby suppressing deterioration characteristics due to high temperature and high voltage.

As a result, the electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention and the electric double layer capacitor including the same can improve the life characteristics of an electrode for an electric double layer capacitor that deteriorates at high temperatures, thereby improving the high-temperature life characteristics of the electric double layer capacitor.

Hereinafter, with reference to the attached drawings, a method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention will be described.

FIG. 3 is a process flow diagram showing a method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention.

As illustrated in FIG. 3, a method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention includes an electrode raw material mixing step (S110), an electrode active material slurry formation step (S120), a coating step (S130), and a rolling step (S140).

Electrode raw material mixing

In the electrode raw material mixing step (S110), activated carbon and conductive material, which are electrode materials, are mixed.

Here, the activated carbon and the conductive agent may be mixed using a ball mill method, but is not limited thereto.

Activated carbon may be one or more selected from hard wood, palm, coconut, petroleum pitch, and phenol. It is preferable to use activated carbon having a high specific surface area of 1,800 to 2,500 m2/g.

The conductive material is not particularly limited as long as it is an electronically conductive material that does not cause a chemical change, and examples thereof include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, Super-P, carbon fiber, and metal powders or metal fibers such as copper, nickel, aluminum, and silver.

Formation of electrode active material slurry

In the electrode active material slurry formation step (S120), a binder, dimethyl siloxane, and a dispersion medium are added to the mixed electrode material and stirred to form an electrode active material slurry.

Here, it is preferable to use a heterogeneous binder as the binder. Specifically, it is preferable to use a binder in which polytetrafluoroethylene (PTFE), a rubber-based resin, and an acrylic resin are added together. In addition, the binder may further include at least one selected from a cellulose-based resin, a fluorine-based resin including polyvinylidene fluoride (PVDF), a thermoplastic resin including polyimide, polyamideimide, polyedylene (PE), and polypropylene (PP), and carboxymethyl cellulose (CMC) and mixtures thereof as a secondary binder.

The dispersion medium may include, but is not limited to, one or more selected from water, butanol, ethanol, isopropyl alcohol, propanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol.

At this stage, it is preferable to perform stirring at a speed of 1,000 to 2,500 rpm for 10 to 60 minutes. If the stirring speed is less than 1,000 rpm or the stirring time is less than 10 minutes, there is a concern that uniform mixing among the electrode material, binder, dimethyl siloxane, and dispersion medium may not occur. On the other hand, if the stirring speed exceeds 2,500 rpm or the stirring time exceeds 60 minutes, it may only increase the manufacturing cost without any further effect, and is therefore not economical.

embrocation

In the application step (S130), the electrode active material slurry is applied to the electrode collector.

Here, the electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may be selected from the group consisting of copper, aluminum, stainless steel, zinc, titanium, silver, palladium, nickel, iron, chromium, alloys thereof, and combinations thereof.

At this stage, the coating can be applied using various methods, such as doctor blade coating, spin coating, dipping coating, spray coating, roll coat coating, gravure printing, bar court coating, die coating, comma coating, or a combination thereof.

Rolling

In the rolling step (S140), the electrode current collector coated with the electrode active material slurry is rolled and dried to form an electrode active material layer.

In this step, rolling can be performed by forming the electrode collector coated with the electrode active material slurry into an electrode shape using a roll press forming machine. The roll press forming machine is intended to improve the electrode density and control the thickness of the electrode through rolling, and is composed of a controller capable of controlling the thickness and heating temperature of the upper and lower rolls, and a winding unit capable of releasing and winding the electrode. The rolling process progresses as the electrode in a roll state passes through the roll press, and this is wound again into a roll state to complete the electrode. At this time, the pressing pressure of the press can be performed at 5 to 20 ton/㎠, but is not limited thereto.

In addition, it is preferable that drying is performed at a temperature of 100 to 250°C for 10 to 180 minutes. If the drying temperature is lower than 100°C or the drying time is lower than 10 minutes, it is not preferable because the dispersion medium is difficult to evaporate and it may be difficult to secure strength. On the contrary, if the drying temperature exceeds 250°C or the drying time exceeds 180 minutes, oxidation of the conductive material may occur, which is not preferable.

After this rolling step, the electrode active material layer preferably contains 85 to 97 wt% of activated carbon, 1 to 10 wt% of conductive material, 1 to 10 wt% of binder, and 1 to 5 wt% of dimethyl siloxane.

Here, dimethyl siloxane is added to the electrode active material layer and uniformly distributed on the surface of the electrode active material layer. When voltage is applied to the negative and positive electrodes including the electrode active material layer to which such dimethyl siloxane is added and high-temperature characteristics are applied, excellent bonding force, heat resistance, and weather resistance are secured through the siloxane bond between the dimethyl siloxane and the electrode material, thereby suppressing deterioration characteristics due to high temperature and high voltage. Accordingly, the present invention can provide an electrode for an electric double layer capacitor (EDLC) with improved high-temperature lifespan compared to an electric double layer capacitor (EDLC) that relies only on the characteristics of activated carbon.

With this, the method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics according to an embodiment of the present invention can be completed.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and cannot be interpreted as limiting the present invention in any way.

Anything not described here is technically inferable enough to be understood by those skilled in the art, so its description will be omitted.

1. Cell manufacturing

Example 1

Electrode manufacturing

Activated carbon and a conductive agent with a specific surface area of 1,800㎡/g were mixed by ball milling. At this time, palm tree-based activated carbon was used, and Super P (trade name M.M.M) (manufacturer CARBON) was used as the conductive agent.

Next, a binder and dimethyl siloxane were added to the mixed electrode material and stirred at a speed of 1,500 rpm to prepare an electrode active material slurry. Here, a mixture of polytetrafluoroethylene, polyvinylidene fluoride, and styrene butadiene rubber was used as the binder. In addition, the electrode active material slurry was mixed in a content ratio of 90 wt% of activated carbon, 3 wt% of conductive material, 6 wt% of binder, and 1 wt% of dimethyl siloxane.

Next, the electrode active material slurry was applied to the metal current collector using a doctor blade.

Next, the metal current collector coated with the electrode active material slurry was rolled using a roll press molding machine at a condition of 10 ton/cm2, and dried at a temperature of 150°C for 60 minutes to form an electrode active material layer, thereby manufacturing an electrode.

Cell production

The manufactured electrodes were used as the cathode and anode, respectively, and the first lead wire was attached to the anode and the second lead wire was attached to the cathode.

Next, a cellulose sheet was placed as a separator between the positive and negative electrodes, and then wound into a roll shape to manufacture a wound element.

Next, after drying the coil element in a vacuum oven, rubber plugs were inserted into the terminals of the first and second leads, and the coil element was impregnated with an electrolyte of 1 mol/L TEABF ₄ /AN.

Next, a winding element was inserted into the inside of a cylindrical case, and the case was curled to manufacture an electric double layer capacitor measuring 10 × 25 mm.

Example 2

An electric double layer capacitor was manufactured in the same manner as in Example 1, except that an electrode active material slurry was used in a mixed content ratio of 90 wt% of activated carbon, 3 wt% of conductive agent, 4 wt% of binder, and 3 wt% of dimethyl siloxane.

Example 3

An electric double layer capacitor was manufactured in the same manner as in Example 1, except that an electrode active material slurry containing 90 wt% activated carbon, 3 wt% conductive agent, 2 wt% binder, and 5 wt% dimethyl siloxane was used.

Comparative Example 1

An electric double layer capacitor was manufactured in the same manner as in Example 1, except that an electrode active material slurry containing 90 wt% activated carbon, 3 wt% conductive agent, and 7 wt% binder was used without adding dimethyl siloxane.

2. Cell performance evaluation

Table 1 shows the composition and composition ratio of electrode active material slurries according to Examples 1 to 3 and Comparative Example 1, and Table 2 shows the results of measuring the initial performance of electric double layer capacitors manufactured according to Examples 1 to 3 and Comparative Example 1.

[Table 1] (Unit: weight%)

[Table 2]

As shown in Tables 1 and 2, the initial performances of the electric double layer capacitors manufactured according to Examples 1 to 3 and Comparative Example 1 all showed a cell voltage of 2.7 V, and the equivalent series resistance (ESR) characteristics were sequentially measured as 17 mΩ, 17 mΩ, 17 mΩ, and 16 mΩ.

3. High temperature characteristics evaluation

Fig. 5 is a graph showing the results of calculating the change rate of the series equivalent resistance (ESR) for the electric double layer capacitor according to Examples 1 to 3 and Comparative Example 1, and Fig. 6 is a graph showing the results of measuring the change rate of the high temperature load capacity for the electric double layer capacitor according to Examples 1 to 3 and Comparative Example 1. At this time, the high temperature characteristic evaluation was conducted by evaluating the electrical characteristics by time zone while applying a rated voltage of 2.7 V at 85°C.

As shown in Fig. 5, the series equivalent resistance (ESR) of the cell was measured at 500-hour intervals while applying the rated voltage (2.7 V) at 85°C, and the results of calculating the series equivalent resistance change rate (ESR change rate, %) by comparing it with the initial value are shown.

In the case of the electric double layer capacitor manufactured according to Comparative Example 1, the ESR change rate range is large, and it can be seen that deterioration is occurring.

On the other hand, in the case of the electric double layer capacitors manufactured according to Examples 1 to 3, it was confirmed that the ESR change rate was significantly reduced compared to the electric double layer capacitor manufactured according to Comparative Example 1 due to the addition of more dimethyl siloxane.

In addition, as shown in Fig. 6, the high temperature load capacity change rate was calculated by measuring the cell's capacitance at 500-hour intervals while applying the rated voltage (2.7 V) at 85°C, and comparing the measured capacitance with the capacitance measured at room temperature before putting it into an oven maintained at 85°C.

In the case of the electric double layer capacitor manufactured according to Comparative Example 1, it can be seen that the range of change in capacity (Cap) is large, and that high-temperature deterioration occurs extremely, resulting in a significant drop in battery performance.

On the other hand, in the case of the electric double layer capacitors manufactured according to Examples 1 to 3, it can be seen that the rate of change in capacity at high temperatures is smaller than that of the electric double layer capacitor manufactured according to Comparative Example 1 due to the addition of more dimethyl siloxane.

Although the above description focuses on the embodiments of the present invention, various changes or modifications can be made at the level of a person skilled in the art having ordinary knowledge in the technical field to which the present invention belongs. Such changes and modifications can be said to belong to the present invention as long as they do not go beyond the scope of the technical idea provided by the present invention. Therefore, the scope of the rights of the present invention should be determined by the claims described below.

100 : Electric double layer capacitor 110 : Case
120: Winding element 122: Cathode
124 : Anode 126 : Separator
130: Sealing rubber 142: First lead wire
144: 2nd lead line
S110: Electrode raw material mixing step
S120: Electrode active material slurry formation step
S130: Application stage
S140 : Rolling stage

Claims (7)

Electrode current collector; and
Including an electrode active material layer formed on at least one surface of the electrode current collector;
The above electrode active material layer comprises activated carbon, a conductive material, a binder and dimethyl siloxane,
The electrode active material layer comprises 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 3 to 5 wt% of the dimethyl siloxane.
An electrode for an electric double layer capacitor with improved high-temperature life characteristics, characterized in that the dimethyl siloxane is added to the electrode active material layer and distributed on the surface of the electrode active material layer to suppress the deterioration characteristics of the electric double layer capacitor due to high temperature and high voltage.
delete In the first paragraph,
The above activated carbon is used with a specific surface area of 1,800 to 2,500㎡/g.
An electrode for an electric double layer capacitor with improved high-temperature life characteristics, characterized in that the electrode has a thickness of 140 to 200 μm.
(a) a step of mixing activated carbon and a conductive agent;
(b) a step of adding a binder, dimethyl siloxane, and a dispersion medium to the mixed electrode material and stirring to form an electrode active material slurry;
(c) a step of applying the electrode active material slurry to the electrode current collector; and
(d) a step of rolling and drying the electrode current collector coated with the electrode active material slurry to form an electrode active material layer;
After the step (d), the electrode active material layer comprises 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 3 to 5 wt% of the dimethyl siloxane.
A method for manufacturing an electrode for an electric double layer capacitor with improved high-temperature life characteristics, characterized in that the dimethyl siloxane is added to the electrode active material layer and distributed on the surface of the electrode active material layer to suppress the deterioration characteristics of the electric double layer capacitor due to high temperature and high voltage.
delete A case in which the inside is impregnated with electrolyte;
a header covering the upper side of the case; and
A wound element is inserted inside the case and is wound by sequentially stacking a cathode, a separator, and an anode;
Each of the above negative and positive electrodes includes an electrode current collector and an electrode active material layer formed on at least one surface of the electrode current collector,
The above electrode active material layer comprises activated carbon, a conductive material, a binder and dimethyl siloxane,
The electrode active material layer comprises 85 to 97 wt% of the activated carbon; 1 to 10 wt% of the conductive material; 1 to 10 wt% of the binder; and 3 to 5 wt% of the dimethyl siloxane.
An electric double layer capacitor including an electrode for an electric double layer capacitor with improved high-temperature life characteristics, characterized in that the dimethyl siloxane is added to the electrode active material layer and distributed on the surface of the electrode active material layer to suppress the deterioration characteristics of the electric double layer capacitor due to high temperature and high voltage. delete

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