KR100923862B1 - Energy storing device - Google Patents

Abstract

The present invention includes a cathode electrode and a cathode electrode, a cathode lead wire and a cathode lead wire, a separator for electrically separating the anode electrode and the cathode electrode located between the anode electrode and the cathode electrode, the anode electrode and the cathode electrode; A housing accommodating the separator, an electrolyte solution contained in the housing, and a positive electrode terminal and a negative electrode terminal to which the positive lead wire and the negative lead wire are respectively connected, and the positive electrode, the negative electrode, and the separator are wound to form an electrode element. The width of the fixing member for maintaining the wound state of the wound electrode element is in the range of 0.1 to 0.5 times the height of the electrode element.

According to the present invention, it is possible to shorten the electrolyte impregnation time to improve the process yield, and also to prevent the loosening of the holding member due to the volume expansion of the electrode and at the same time maintain the distance between the electrodes to improve the electrical resistance characteristics. have.

Energy, storage, electrode element, winding, fixed

Description

Energy Storage Device {ENERGY STORING DEVICE}

The present invention relates to an energy storage device, and more particularly, to an energy storage device having a width of a fixing member for maintaining a wound state of a wound electrode element in a range of 0.1 to 0.5 times the height of the electrode element. will be.

In general, a battery and a capacitor are typical elements for storing electrical energy.

Ultra Capacitor, also called Super Capacitor, is an energy storage device with intermediate characteristics between an electrolytic capacitor and a secondary battery.The next generation that can be used and replaced with a secondary battery due to its high efficiency and semi-permanent life characteristics It is an energy storage device.

Ultracapacitors can be divided into electric double layer capacitors (EDLC) and pseudocapacitors according to energy storage mechanisms.

Pseudocapacitors utilize the phenomenon that charges accumulate inside or near the surface of an electrode, while EDLC uses the property of charge adsorption on an electrical double layer between the electrode and the electrolyte interface.

EDLC forms an electric double layer on the surface of the electrode material and the contact surface of the electrolyte by using a material having a large surface area such as activated carbon as an active material of the electrode.

That is, charge layers having different polarities at the interface between the electrode and the electrolyte solution are generated by the electrostatic effect. The charge distribution thus formed is called an electric double layer, and as a result, it has the same capacitance as in a battery.

However, the electric double layer capacitor has different charge / discharge characteristics from the battery, whereas the voltage characteristics of the battery during charge / discharge are similar to those of the plateau, In the case of the electric double layer capacitor, the voltage characteristic with time shows a linear graph characteristic during the charge / discharge process.

Therefore, the electric double layer capacitor has a characteristic that the amount of charged / discharged energy can be easily calculated by measuring a voltage.

On the other hand, the electric double layer capacitor as described above, because the mechanism for storing electricity stores the electric charge in the electric double layer formed at the interface of the electrolyte, unlike the storage battery using a chemical reaction, that is, because it uses the electrical storage by the accumulation of physical charge, No deterioration due to repeated use, high reversibility and long service life.

Therefore, it may be used as a battery replacement for applications that are not easy to maintain and require a long service life.

On the other hand, as described above, the electric double layer capacitor has a fast charging characteristic because it uses the principle of absorbing / desorbing the electric double layer generated at the interface between the electrode and the electrolyte, and thus has a mobile communication information device such as a mobile phone, laptop, PDA, etc. It is very suitable as main power supply or auxiliary power supply for electric vehicles, night road lights, uninterrupted power supply (UPS), etc. as well as auxiliary power supply of high capacity.

The electrodes of the electric double layer capacitor having such various uses have high energy through a large specific surface area, high power through low specific resistance, and electrochemical stability through suppression of an electrochemical reaction at an interface.

Therefore, currently active carbon powder or activated carbon fiber having a large specific surface area is most widely used as a main material of the electrode, and a low specific resistance is realized by mixing a conductor or spray coating of metal powder.

In addition, research and development of a more stable electrode material by suppressing the electrochemical side reactions occurring at the electrode interface through various methods.

However, in the case of the electric double layer capacitor, positive and negative ions in the electrolyte are transported and adsorbed to the porous electrode material. At this time, the electrode material expands as ions penetrate into the porous active material layer of the electrode material.

In order to prevent loosening of the electrode caused by such an expansion phenomenon, in the finishing operation of the wound electrode element of the electric double layer capacitor, the finishing taping operation is performed using a fixing member.

In this finishing taping operation, the width and thickness of the fixing member have a major influence on the process time required for the electrolyte impregnation and the distance adhesion between the electrodes due to the volume expansion of the electrode material according to the impregnation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an energy storage device capable of shortening an electrolyte impregnation time to improve process yield by appropriately adjusting the width of a fixing member for fixing an electrode element.

Another object of the present invention, by appropriately adjusting the width of the fixing member, to prevent the loosening of the fixing member due to the volume expansion of the electrode and at the same time to maintain a uniform distance between the electrodes to improve the electrical resistance characteristics energy It is to provide a storage device.

The object is, according to the present invention, the anode electrode and the cathode electrode, the anode lead wire and the cathode lead wire, a separator for electrically separating the cathode electrode and the cathode electrode located between the anode electrode and the cathode electrode, and the anode A housing accommodating an electrode, a cathode electrode, and a separator; an electrolyte solution contained in the housing; and a cathode terminal and a cathode terminal to which the anode lead line and the cathode lead line are respectively connected; and the cathode electrode, the cathode electrode, and the separator are wound. Forming an electrode element, the width of the fixing member for maintaining the wound state of the wound electrode element is formed in the range of 0.1 to 0.5 times the height of the electrode element.

Here, the fixing member may be composed of two or more.

In addition, an adhesive is applied to the fixing member, and the thickness of the fixing member to which the adhesive is applied may be 150 micrometers or less.

Preferably, the fixing member is made of one of polypropylene or polyethylene or polyimide or polyethylene terephthalate.

According to the present invention, the electrolyte solution impregnation time can be shortened and the process yield can be improved.

In addition, it is possible to prevent the loosening of the fixing member due to the volume expansion of the electrode and at the same time maintain the distance between the electrodes to improve the electrical resistance characteristics.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration of the present invention.

Prior to this, the terms used in this specification and claims should not be construed in a dictionary sense, and the inventors may properly define the concept of terms in order to explain their invention in the best way. It should be construed as meaning and concept consistent with the technical spirit of the present invention.

Therefore, the configurations shown in the embodiments and drawings described herein are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It is to be understood that water and variations may exist.

1 is a front view showing an appearance according to an embodiment of the energy storage device according to the present invention, Figure 2 is a front view showing a state in which the electrode and the first lead wire of the energy storage device according to the invention, Figure 3 4 is a plan view showing a state in which an electrode and a separator of an energy storage device according to the present invention are disposed, and FIG. 4 is a perspective view illustrating a state in which an electrode element of the energy storage device according to the present invention is wound.

1 to 4, the cell of the energy storage device 100 according to the present invention includes a load housing 40 made of a metal material and an anode electrode 10 and a cathode electrode 20 embedded in the housing 40. It includes.

The anode electrode 10 includes an active material layer 4 composed of a metallic current collector 2 and porous activated carbon, and the anode lead wire 6 is connected to one side thereof.

The current collector 2 is usually configured in the form of a metal foil, and the active material layer 4 is composed of a form of coating coated on both surfaces of the metal current collector 2 as activated carbon.

The active material layers 4 and 14 are portions for storing electrical energy of the positive electrode and the negative electrode, and the current collectors 2 and 12 serve as transfer paths of charges emitted or supplied from the active material layer.

Separation membranes 30 and 32 are disposed between the anode and cathode electrodes 10 and 20 sequentially stacked to limit electron conduction between the anode electrode 10 and the cathode electrode 20 and the housing 40. Is filled with an electrolyte solution.

In this case, the porous active material layers 4 and 14 have a large surface area including pores that are almost circular in shape, and act as an active material on the anode electrode 10 and the cathode electrode 20 in the same manner. Each surface comes into contact with the electrolyte.

When voltage is applied to the electrodes 10 and 20, the positive and negative ions contained in the electrolyte move to the positive electrode 10 and the negative electrode 20, respectively, to the pores of the porous active material layers 4 and 14. Infiltrate.

The anode electrode 10, the cathode electrode 20, and the separator 30 stacked as described above are wound in a circle to form an electrode element, and are accommodated in the housing 40.

The housing 40 may be made of a metallic or synthetic resin material, preferably made of aluminum or an alloy thereof.

Preferably, the housing may be composed of a lower housing and an upper housing, wherein the lower housing is configured to electrically separate the anode / cathode electrodes 10 and 20 and the cathode / cathode electrodes 10 and 20. It is a component for accommodating the separators 30 and 32 and the lead wires 6 and 16.

The upper housing is combined with the lower housing seen from the top of the lower housing, the upper housing may also be composed of a metallic or synthetic resin material, preferably composed of aluminum or an alloy thereof.

The upper housing is coupled to the positive terminal 66 and the negative terminal 76 to which the positive lead wire 6 and the negative lead wire 16 are connected, respectively.

Here, the positive electrode terminal 66 and the negative electrode terminal 76 may be formed of any one of aluminum, steel (steel) or stainless steel to ensure mechanical strength, the surface is formed by coating by nickel or tin It can be configured to secure the bonding by soldering or the like.

Preferably, the positive electrode terminal and the negative electrode terminal 66, 76 are disposed in the direction perpendicular to each other in the processing error range on the upper housing 50.

As described above, since the positive electrode terminal and the negative electrode terminals 66 and 76 are disposed in a direction perpendicular to each other, almost the same bearing force may be generated in which direction the bending moment due to external force acts.

5 is a perspective view showing a state in which a fixing member is wound around an electrode element in the energy storage device according to the present invention.

Referring to FIG. 5, the width of the fixing member 17 for maintaining the wound state of the wound electrode element 15 is formed in a range of 0.1 to 0.5 times the height h of the electrode element.

In the case of electrolyte impregnation, the electrode material swells due to the ions penetrated into the active material layer but is increased in volume.

Therefore, in the case of the portion of the electrode element 15 in which the fixing member 17 is wound, the volume is fixed by the fixing member 17, but in the case of the portion in which the fixing member 17 is not wound, the fixing member 17 is fixed. The volume increases linearly from the end of the electrode to the end of the electrode element 15.

In particular, when the width of the fixing member 17 is formed to be less than 0.1 times narrower than the height h of the electrode element, the upper and lower ends of the electrode element 15 when the electrolyte is impregnated with the fixing member 17. There is a problem that is inflated to the outside excessively compared to the wound portion.

As described above, when the upper and lower ends of the electrode element 15 are swollen to the outside, the distance between the electrodes in the electrode element becomes nonuniform, resulting in deterioration of the flow characteristics of the current, which in turn reduces the electrical efficiency of the energy storage device. Will result.

Therefore, the width of the fixing member 17 is preferably formed at least 0.1 times greater than the height h of the electrode element.

On the other hand, when the width of the fixing member 17 is more than 0.5 times the height (h) of the electrode element, the time required for such an electrolyte impregnation when the electrode element 15 is impregnated with the electrolyte solution is excessively increased This occurred.

For the electrode element 15 having a radius of 18 mm and a height of 40 mm, the width of the fixing member 17 is 100%, 75%, 50%, 40%, 25%, 10, respectively, relative to the height of the electrode element. In the state formed in% or the like, the electrolyte solution impregnation amount after a predetermined time was 2.12g, 2.64g, 3.42g, 3.94g, 3.92g, 3.91g, respectively.

As can be seen in the above experiment, when the width of the fixing member 17 to the electrode element 15 exceeds 50%, it can be seen that the amount of electrolyte solution impregnated decreases as a result after a certain time. have.

This is because the electrolyte does not pass through the portion where the fixing member 17 is wound when the electrolyte is impregnated, and thus, the electrode is prevented by the capillary force of the portion where the fixing member 17 is not wound in the electrode element 15. This is because the electrolyte solution must penetrate into the element 15.

Therefore, when the width of the fixing member 17 is formed too large compared to the height of the electrode element 15, the time required to soak the electrolyte by the capillary force as described above is excessively increased to produce the entire energy storage device The yield will be reduced.

Therefore, the width of the fixing member 17 is preferably formed within 50% of the overall height of the electrode element 15.

At this time, when the electrode is fixed by the fixing member 17, the tape-shaped fixing member is wound 1 to 2 turns along the circumference of the electrode element, and the adhesive layer applied to the fixing member 17 is not coated with the adhesive. It is preferable to be wound up so as to adhere to the back surface.

As the adhesive, for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, and the like may be used. As the acrylic adhesive, 50 to 100% by weight of the main monomer, 0 to 50% by weight of the comonomer and 0 to 50% by weight Copolymers obtained by copolymerization of functional group-containing monomers of may be used.

The acrylic adhesive may also include tackifying polymeric materials such as rosin, terpene resins, terpene-phenolic resins and petroleum resins, crosslinkers and other additives.

As the rubber adhesive, an adhesive obtained by mixing a natural rubber or a synthetic rubber with a tackifying polymer material, a phenolic anti-aging agent, a metal oxide, or the like as necessary may be used.

As the silicone-based adhesive, for example, an adhesive obtained by peroxidation and thermosetting using a polysiloxane containing an alkyl group or a phenyl group, or a cured product obtained by the addition reaction of a hydrosilane and a vinyl group-containing polysiloxane may be used.

If the thickness of the fixing member is very thin, the elasticity may be lowered due to the volume change due to impregnation or charging and discharging of the electrode element, and thus the fixing may be released or broken. Since the electrode element directly receives the pressure acting due to the volume change caused by the discharge, the electrical efficiency of the electrode element is reduced after a long time.

Therefore, the thickness of the entire fixing member 17 including the adhesive layer is preferably formed to be 150 micrometers or less.

As the material of the fixing member, a pressure-sensitive adhesive tape containing polyethylene, polyethylene terephthalate (PET), polypropylene (PP), polyphenylene sulfide (PPS), or the like as a support base material, or unstretched polyimide (PI) ) Or polyetherimide (PEI) can be used.

On the other hand, the fixing member 17 may be divided into two or more in order to form the width of the fixing member 17 with respect to the height of the electrode element 15 in the above range.

That is, the fixing member 17 for forming the width of the range is divided into two, one may be disposed on the upper portion of the electrode element 15, the other is disposed below the electrode element 15.

Thus, the total sum of the widths of the fixing members 17 may be configured to be in the range of 0.1 to 0.5 times the height h of the electrode element 15.

Experimental Example

For the electrode element with a radius of 18 mm and a height of 40 mm, the width of the fixing member was different from that of the electrode element.

Experimental Example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Experimental Example 5 Experimental Example 6 Fixed member width 100% 75% 50% 40% 25% 10% Electrolyte impregnation 2.12 g 2.64g 3.42 g 3.94 g 3.92g 3.91g

After a certain period of time (5 minutes), the electrolyte impregnation amount was measured, it can be seen that the width of the holding member is more than 50% compared to the height of the electrode element is rapidly reduced.

As mentioned above, although the present invention has been described by way of limited embodiments and drawings, the technical idea of the present invention is not limited thereto, and a person having ordinary skill in the art to which the present invention pertains, Various modifications and variations may be made without departing from the scope of the appended claims.

1 is a front view showing an appearance according to an embodiment of the energy storage device according to the present invention,

2 is a front view illustrating a state in which an electrode and a first lead wire of an energy storage device according to the present invention are connected;

3 is a plan view illustrating a state where electrodes and separators of an energy storage device according to the present invention are disposed;

4 is a perspective view showing a state in which an electrode element of the energy storage device according to the present invention is wound;

5 is a perspective view showing a state in which a fixing member is wound around an electrode element in the energy storage device according to the present invention.

* Description of the symbols for the main parts of the drawings *

6, 16: anode lead wire / cathode lead wire 10, 20: anode electrode / cathode electrode

15: electrode element 17: fixing member

30: separator 40: housing

Claims (4)

An anode electrode and a cathode electrode; A positive lead wire and a negative lead wire; A separator disposed between the anode electrode and the cathode electrode to electrically separate the cathode electrode and the cathode electrode; A housing accommodating the positive electrode, the negative electrode and the separator; An electrolyte solution contained in the housing; A positive electrode terminal and a negative electrode terminal to which the positive lead wire and the negative lead wire are respectively connected; The positive electrode, the negative electrode and the separator are wound to form an electrode element, The width of the fixing member for maintaining the wound state of the wound electrode element is formed in the range of 0.1 to 0.5 times the height of the electrode element, An adhesive is applied to the fixing member, and the thickness of the fixing member to which the adhesive is applied is characterized in that the energy storage device of 150 micrometers or less. The method of claim 1, The energy storage device, characterized in that the fixing member is composed of two or more. delete The method according to claim 1 or 2, The fixing member is made of any one of polypropylene or polyethylene or polyimide or polyethylene terephthalate.

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