KR100884751B1 - Sealed primary film battery having electrolytic layer obtained from aqueous electrolyte composition - Google Patents

Abstract

Disclosed is a sealed film primary battery having an electrolyte layer obtained from an aqueous electrolyte composition containing hydrophilic fine particles. The sealed film primary battery according to the present invention is formed in a separator between a positive electrode and a negative electrode, and a plurality of through holes are formed in the separator. The non-flowing electrolyte layer between the positive electrode and the negative electrode includes a first electrolyte layer and a second electrolyte layer extending in parallel with each electrode, and a plurality of filling the inside of the through hole of the separator so as to be integrally connected thereto. And a third electrolyte layer. The third electrolyte filled in the through hole formed in the separator shortens the ion migration path in the electrolyte. Hydrophilic microparticles | fine-particles for disperse | distributing moisture to the outside are disperse | distributed to the electrolyte layer.

Hermetic, Film Primary Battery, Aqueous Electrolyte, Hydrophilic Particles, Separator, Through Hole

Description

Sealed primary film battery having electrolytic layer obtained from aqueous electrolyte composition

The present invention relates to a hermetic film primary battery, and more particularly to a hermetic film primary battery having an electrolyte layer obtained from an aqueous electrolyte composition. The present invention is derived from the research conducted as part of IT next generation core technology development project of the Ministry of Information and Communication [Task management number: 2005-S-106-02, Task name: Development of sensor tag and sensor node technology for RFID / USN] .

Recently, research on active radio frequency identification (RFID) and sensor node technologies has been actively conducted. These technologies, together with digital TV, home network, and intelligent robots, are very large and massive, surpassing the current Code Devision Multiple Access (CDMA) technology, and are expected to become a core industry in the future. In other words, the reader not only increases the recognition distance of the tag, but also senses the object information and the environment information around the tag by deviating from the existing passive function of reading the information contained in the tag through the reader. Ultimately, it is expected that the area of information flow can be extended from communication between people and things through networking to communication between things. Therefore, in order to drive the radio wave identification tag and the sensor node, it is important to secure its own power source completely independent of the reader by using a power source having a small size, light weight, and long lifespan suitable for the tag or node standard.

To date, film primary batteries have been used as one of power supply elements that have been partially applied to radio frequency identification tags and sensor nodes and have been recognized for their potential. The film primary battery has the same electrode and electrolyte composition as a conventional battery and alkaline battery, but is implemented in a laminated film form using a PET-based packaging material instead of a cylindrical can as a supporting container. As described above, many problems have arisen when the electrolyte used in the conventional cylindrical cans is applied to the battery in the film form while manufacturing the battery in the film form. For example, when a cylindrical cell is applied, an aqueous electrolyte is injected so that the empty space in the can is filled after the separator is inserted between the electrodes because it is sealed. On the other hand, the battery in the form of a film is obtained by simply laminating the electrode and the separator, there is a problem in that the contact between each electrode and the electrolyte is weakened to increase the interface resistance. In addition, due to the limited space between the films, there is a limit in sufficiently injecting the electrolyte into the space between the two electrodes. In addition, since the cell is not a completely sealed structure, when the battery is left for a long time or left at a high temperature, the electrolyte constituting the electrolyte may be dried, leading to a sharp drop in performance.

In particular, in the film primary battery according to the related art proposed so far, since the electrolyte cannot be sufficiently injected, the electrolyte layer was formed by using a porous material membrane as a separator inserted between both batteries and impregnating the electrolyte in the separator. However, the film primary battery manufactured by the above method has a limitation in reducing the total thickness of the film primary battery because a separator having a predetermined thickness or more is required, and the irregularly formed pores in which the ion migration path in the electrolyte layer is formed in the separator. Since it is formed along the ion migration path is long and irregular, the internal resistance is increased, the output characteristics are degraded, there is a problem that the performance of the continuous discharge at a high rate or a sharp drop in pulse discharge. In addition, in the case of using a separator made of a cellulose-based or nonwoven-based material as the porous separator, there is a problem that the separator is deformed or melted by the electrolyte when a strong acid or a strong base electrolyte is used, thereby reducing the performance of the battery when the battery is stored for a long time, or There is also the problem of freezing.

The present invention is to solve the above problems in the prior art, it is possible to suppress the evaporation of water in the electrolyte, using an aqueous electrolyte composition that can be usefully used with a separator having resistance to strong acids or strong base electrolyte solution By shortening the ion migration path in the electrolyte layer to improve the output characteristics of the battery, it is to provide a sealed film primary battery that can implement a thinner film primary battery.

In order to achieve the above object, the hermetic film primary battery according to the present invention extends in parallel with the positive electrode, the negative electrode, and a predetermined distance from them between the positive electrode and the negative electrode, respectively, and a plurality of through holes are formed. And a separator formed of a thin film and a non-flowable electrolyte layer filled in the space between the anode and the cathode. The electrolyte layer includes a first electrolyte layer extending in parallel with the anode between the anode and the separator, a second electrolyte layer extending in parallel with the cathode between the cathode and the separator; And a plurality of third electrolyte layers filling the inside of the through hole of the separator to be integrally connected to the first electrolyte layer and the second electrolyte layer, respectively.

The separator may be made of a hydrophobic polymer, a woven glass fiber, or a woven carbon fiber.

The electrolyte layer may be formed of a mixture of a water-soluble polymer, an aqueous electrolyte solution, and hydrophilic fine particles. The hydrophilic fine particles may be made of a porous inorganic material or an organic material.

The aqueous electrolyte composition according to the present invention contains hydrophilic fine particles. An aqueous electrolyte solution is impregnated in the porous inorganic material or organic material constituting the hydrophilic fine particles to prevent the aqueous electrolyte solution from evaporating to the outside. By using the aqueous electrolyte composition according to the present invention containing hydrophilic fine particles as described above, an electrolyte layer in which the hydrophilic fine particles are dispersed is formed on both surfaces of the separator having a plurality of through holes, thereby suppressing evaporation of water from the electrolyte layer. can do. In addition, the water-soluble polymer included in the electrolyte composition according to the present invention may have excellent adhesion or solidify after evaporation of the solvent, thereby allowing the electrode and the separator to be integrated by the electrolyte layer.

The sealed film primary battery according to the present invention provides excellent ion conductivity by a shortened ion migration path provided by an electrolyte layer formed in a through hole formed in a separator, thereby improving high rate discharge characteristics, high output characteristics, and pulse output characteristics. In addition, even during long-term storage and long-term discharge can be prevented from deteriorating the battery can provide excellent long-term stability. In addition, since the through hole formed in the separator is used as an ion migration path, the separator can be formed of a material having excellent resistance to strong acids or strong bases, and thus it is possible to prevent deformation such as corrosion or shrinkage of the separator even in long-term use. It is possible to extend the lifespan and to form a thinner separator, which makes the battery even thinner.

The sealed film primary battery according to the present invention can be manufactured using the equipment used in the existing battery manufacturing process as it is, it is easy to automate, serialization and mass production by low unit cost.

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of main parts of a sealed film primary battery 100 according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view showing a partial structure of a portion along the line II-II 'of FIG. 1.

1 and 2, the sealed film primary battery 100 according to a preferred embodiment of the present invention includes a positive electrode 110, a negative electrode 120, and a separator 130 interposed therebetween. .

The separator 130 extends in parallel with the anode 110 and the cathode 120 while being spaced apart from the cathode 110 and the cathode 120 by a predetermined distance d ₁ and d ₂ , respectively. The separator 130 may have a thickness of about 5 to 500 ㎛.

The separator 130 is made of a hydrophobic material. In addition, the separator 130 may be made of a porous or non-porous material.

The separator 130 may be made of a hydrophobic polymer. For example, the separator 130 may be formed of a mixture of polyethylene, polytetrafluoroethylene, polystyrene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, vinylidene fluoride, and hexafluoropropylene. Copolymer, copolymer of vinylidene fluoride and trifluoroethylene, copolymer of vinylidene fluoride and tetrafluoroethylene, nylon, polyacrylonitrile, ethyl vinyl alcohol, polyethylene terephthalate (PET), polybutylene Terephthalate (PBT), polysulfone, polyimide, polyurethane, polybutadiene, polymethylacrylate, polyethylacrylate, polymethylmethacrylate, polyethylmethacrylate, polybutylacrylate, and polybutylmethacryl Any one of polymers selected from the group consisting of latex polymers, or Is selected it may be made at least to the two kinds of polymer blend. Alternatively, the separator 130 may be made of woven glass fibers or carbon fibers.

3 is a plan view illustrating a configuration of an exemplary separator 130A that may be used as the separator 130.

As illustrated in FIG. 3, the separator 130A is formed of a hydrophobic thin film 134 having a rolled film, and the plurality of through holes 132 are formed in the hydrophobic thin film 134. 3 illustrates that the through hole 132 has a circular shape. However, the present invention is not limited to this. That is, the through hole 132 may be formed to have an oval or polygonal shape. The through hole 132 has a relatively large opening width W ₁ of about 10 μm to 2 mm.

4 is a plan view illustrating a configuration of another exemplary separator 130B that may be used as the separator 130.

As illustrated in FIG. 4, the separator 130B is formed of a woven thin film 234, and a plurality of through holes 232 are formed in the thin film 234. The through hole 232 may have an opening width W ₂ of about 10 μm to 2 mm.

Referring back to FIGS. 1 and 2, the non-flowing electrolyte layer 140 filling the space is formed in the space between the anode 110 and the cathode 120. The electrolyte layer 140 may include a first electrolyte layer 142 extending in parallel with the anode 110 between the anode 110 and the separator 130, the cathode 120, and the separator 120. The second electrolyte layer 144 extending in parallel with the cathode 120 between the 130 and the first electrolyte layer 142 and the second electrolyte layer 144 are integrally connected to each other. A plurality of third electrolyte layers 146 filling the inside of the through hole 132 or 232 of the separator 130 is included. The third electrolyte layer 146 has a width d ₃ determined according to the opening width W ₁ or W ₂ of the through hole 132 or 232 of the separator 130. The third electrolyte layer 146 is provided in the sealed film primary cell 100 by providing a shorter path of movement of ions present in the electrolyte layer 140 between the anode 110 and the cathode 120. It reduces internal resistance and improves output characteristics.

The first electrolyte layer 142 and the second electrolyte layer 144 may be formed to have a thickness of about 10 to 300 ㎛ each.

The electrolyte layer 140 may be formed of a mixture of a water-soluble polymer, an aqueous electrolyte solution, and hydrophilic fine particles. The hydrophilic fine particles have a function of inhibiting evaporation of the electrolyte by interacting with the aqueous solution in a state dispersed in the aqueous electrolyte in the electrolyte layer 140.

The water-soluble polymer included in the electrolyte layer 140 is, for example, polyethylene oxide, polypropylene oxide, starch, polyacrylic acid, polyvinyl alcohol, polyvinylacetate, cellulose, cellulose acetate, carboxymethyl cellulose, agar, and It may be made of any one polymer selected from the group consisting of Nafion polymer, or a blend of at least two polymers selected from these.

The aqueous electrolyte solution included in the electrolyte layer 140 is, for example, potassium hydroxide (KOH), sodium hydroxide (NaOH), potassium bromide (KBr), potassium chloride (KCl), sodium chloride (NaCl), and zinc chloride (ZnCl ₂ ). , Ammonium chloride (NH ₄ Cl), sulfuric acid (H ₂ SO ₄ ), or an aqueous solution containing a Nafion electrolyte.

The hydrophilic fine particles included in the electrolyte layer 140 may be made of a porous inorganic material or an organic material. When the hydrophilic fine particles are made of a porous inorganic material, the hydrophilic fine particles may be made of silica, talc, alumina (Al ₂ O ₃ ), titania (TiO ₂ ), clay, or zeolite. In addition, when the hydrophilic fine particles are made of an organic material, the hydrophilic fine particles may be made of polyethyleneimine, ethylene glycol, or polyethylene glycol.

An exemplary method for forming the electrolyte layer 140 of the sealed film primary battery 100 according to the present invention is as follows.

First, an aqueous electrolyte composition according to the present invention is prepared. In order to prepare the aqueous electrolyte composition according to the present invention, a water-soluble polymer, an aqueous electrolyte solution, and hydrophilic fine particles are prepared. In addition, a separator 130 having the same structure as the separator 130A illustrated in FIG. 3 or the separator 130B illustrated in FIG. 4 is prepared. Details of the constituent materials of the water-soluble polymer, the aqueous electrolyte solution, and the hydrophilic fine particles are as described above. The aqueous electrolyte solution may be formed of, for example, an electrolyte in which the predetermined electrolyte illustrated above is dissolved in distilled water at a concentration of about 1 to 8 M. In order to form the separator 130, a plurality of through holes 132 may be formed by drilling a hydrophobic polymer film. Alternatively, glass fibers or carbon fibers woven to form the through holes 232 may be used as the separator 130. The through hole 132 or 232 has a relatively large opening size that is visible to the naked eye.

The polymer electrolyte solution is prepared by mixing the water-soluble polymer, the aqueous electrolyte solution, and the hydrophilic fine particles. To this end, first, the hydrophilic particulate additive is added to the aqueous electrolyte to obtain a mixture. Here, the hydrophilic fine particles may be added in an amount of about 0.1 to 50% by weight based on the total weight of the aqueous electrolyte. Thereafter, the water-soluble polymer is dissolved in the mixture to prepare a polymer electrolyte in the form of a slurry or a solution having a very high viscosity. The obtained electrolyte mixture is coated on both sides of the separator to a predetermined thickness and dried. While the electrolyte mixture is coated, the inside of the through hole formed in the separator is filled with the electrolyte mixture, and a membrane having a uniform thickness formed of the electrolyte mixture is formed on the surface of the separator. When the coated electrolyte mixture is dried, a non-flowing electrolyte layer such as a gel or a paste is formed. The electrolyte layer may have a tackiness according to the type of the water-soluble polymer used, and may have a structure in which the solvent is solidified after evaporation and integrated with the separator. The electrolyte layer is the first electrolyte layer 142 and the second electrolyte layer 144 covering the both sides of the separator 130, like the electrolyte layer 140 illustrated in FIG. It includes a plurality of third electrolyte layer 146 filling the inside of the through hole 132 or 232 of the separation membrane 130 to be connected.

An integrated battery may be configured by forming a positive electrode and a negative electrode on both sides of a coupling structure between the separator 130 and the electrolyte layer 140 obtained through the above process. As described above, the sealed film primary battery 100 according to the present invention may include a third electrolyte layer of the electrolyte layer 130 filled in the through hole 132 or 232 of the separator 130 in the electrolyte layer 130. Since the ions move through a short moving path through 136, excellent output characteristics can be obtained, and even if the thickness of the separator 130 is reduced to half or less than that of the separator according to the prior art, the desired level of ion conductivity can be obtained. Since the film primary battery can be obtained, the film primary battery can be further thinned.

Next, specific examples of the aqueous electrolyte composition and the sealed film primary battery according to the present invention will be described in more detail. However, the following preparation examples are illustrated to help the understanding of the present invention, and the scope of the present invention should not be construed as being limited thereto, and various modifications and changes from the following preparation examples without departing from the spirit of the present invention. This is possible.

Example  One

After preparing a porous polyethylene (PE) film having a thickness of 20 μm, a plurality of circular through holes having a diameter of 500 μm were formed in the film using a perforator to prepare a separator.

In order to prepare the aqueous electrolyte composition, first, polyimide, which is hydrophilic fine particles, in a 6 M potassium hydroxide (KOH) solution is added in an amount of 5% by weight, and the polyacrylic acid and carboxymethylcellulose mixed in a weight ratio of 1: 1 are added thereto. The polymer blend was added at a concentration of 10% by weight to prepare a very waxy electrolyte gel. The electrolyte gel thus obtained was coated on both surfaces of the separator to form an electrolyte layer. At this time, in the process of coating the electrolyte gel on the surface of the separator, the electrolyte gel was introduced into each through hole formed in the separator so that the inside of the through hole was completely filled with the electrolyte gel.

The cathode and anode films were laminated on the electrolyte layers exposed on both surfaces of the bonding structure between the separator and the electrolyte layer prepared as described above, and then sealed and bonded to prepare a sealed film primary battery. Here, the polyethylene terephthalate (PET) film and the conductive carbon is coated and pressed on the exposed surface of the electrolyte layer covering one surface of the separator, and then EMD (electrolytic MnO ₂ ), a binder, and a conductive material are placed therein. The prepared slurry was coated to form a positive electrode. Then, a negative electrode was formed by coating a slurry prepared by mixing Zn particles, a binder, and a conductive material on the exposed surface of the electrolyte layer covering the other side surface of the separator.

Example  2

A sealed film primary battery was manufactured in the same manner as in Example 1, except that a polymer blend of polyethylene oxide and polyvinyl alcohol mixed in a weight ratio of 1: 1 was used instead of a polymer blend of polyacrylic acid and carboxymethyl cellulose. It was.

Example  3

Example 1, except that woven glass fibers having a thickness of 100 μm was used as a separator and 6 M aqueous solution of ammonium chloride (NH ₄ Cl) was used instead of 6 M potassium hydroxide (KOH) solution to prepare an aqueous electrolyte composition. In the same manner as in the sealed film primary battery was prepared.

Control

A conventional liner paper / ammonium chloride electrolyte system applied to manganese and alkaline batteries according to the prior art was prepared. To this end, 120 M thick liner paper was impregnated with 6 M aqueous ammonium chloride solution. In the electrolyte system, a cathode and an anode were formed in the same manner as in Example 1 to form a film primary battery.

5 is a graph showing the results of comparing the ion conductivity of the sealed film primary batteries prepared in Examples 1 to 3 to the case of the comparative example in order to evaluate the ion conductivity characteristics of the sealed film primary battery according to the present invention.

As shown in FIG. 5, Examples 1 to 3 showed better ion conductivity than those of the control example. From the results in FIG. 5, it can be seen that in the case of Examples 1 to 3, the ion path per unit length is shortened under the same voltage application conditions, thereby improving the ion conductivity. As a result, the improved ion conductivity provides excellent high rate discharge and high output characteristics.

6 is a result of comparing the ion conductivity of the sealed film primary batteries prepared in Examples 1 to 3, respectively, in order to evaluate the amount of change in ion conductivity according to the temperature change of the sealed film primary battery according to the present invention. The graph shown.

As shown in FIG. 6, in the case of Examples 1 to 3, when the ion conductivity was measured while the temperature was raised to 80 ° C., the ion conductivity showed a substantially constant value with little change in the ion conductivity. From the results of FIG. 6, it can be seen that the sealed film primary batteries prepared in Examples 1 to 3 significantly suppressed the deterioration in performance due to evaporation of the electrolyte during long-term storage and standing.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes by those skilled in the art within the spirit and scope of the present invention. This is possible.

1 is a perspective view of main parts of a sealed film primary battery according to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a partial structure of a portion along the line II-II 'of FIG. 1.

Figure 3 is a plan view showing the configuration of an exemplary separator of a sealed film primary battery according to a preferred embodiment of the present invention.

4 is a plan view showing the configuration of another exemplary separator of a sealed film primary battery according to a preferred embodiment of the present invention.

5 is a graph showing the results of comparing the ion conductivity characteristics of the sealed film primary batteries according to the present invention with the control example.

6 is a graph showing a result of comparing the change in ion conductivity with the temperature change of the sealed film primary batteries according to the present invention compared with the case of the comparative example.

<Explanation of symbols for the main parts of the drawings>

100: sealed film primary battery, 110: positive electrode, 120: negative electrode, 130, 130A, 130B: separator, 132: through hole, 134: hydrophobic thin film, 140: electrolyte layer, 142: first electrolyte layer, 144: second electrolyte Layer 146: third electrolyte layer, 232: through hole, 234: thin film.

Claims (11)

With the anode, With a cathode, A separator formed between a thin film having a plurality of through holes extending in parallel with the anode and the cathode and being spaced apart from each other by a predetermined distance; A non-flowable electrolyte layer filled in the space between the positive electrode and the negative electrode, The separator extends in a thickness of a first size between the anode and the cathode, and each of the plurality of through holes has an opening width of a second size larger than the first size, The electrolyte layer includes a first electrolyte layer extending in parallel with the anode between the anode and the separator, a second electrolyte layer extending in parallel with the cathode between the cathode and the separator; The sealed film primary battery comprising a plurality of third electrolyte layers filling the inside of the through hole of the separator so as to be integrally connected to the first electrolyte layer and the second electrolyte layer, respectively. The method of claim 1, The separator is a sealed film primary battery, characterized in that made of a hydrophobic polymer. The method of claim 2, The separator is polyethylene, polytetrafluoroethylene, polystyrene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, copolymer of vinylidene fluoride and hexafluoropropylene, vinylidene fluoride And copolymers of trifluoroethylene, copolymers of vinylidene fluoride and tetrafluoroethylene, nylon, polyacrylonitrile, ethyl vinyl alcohol, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), In the group consisting of polysulfone, polyimide, polyurethane, polybutadiene, polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl acrylate, and polybutyl methacrylate polymer Any polymer selected, or red selected from these FIG hermetic film primary batteries which comprises a polymer blend of two kinds. The method of claim 1, The separator is a sealed film primary battery, characterized in that made of woven glass fibers or carbon fibers. The method of claim 1, The plurality of through holes each have an opening width of 10 μm to 2 mm. The method of claim 1, The separator is a sealed film primary battery, characterized in that having a thickness of 5 ~ 500 ㎛. The method of claim 1, The first electrolyte layer and the second electrolyte layer each have a thickness of 10 ~ 300 ㎛ sealed film primary battery, characterized in that. The method of claim 1, The electrolyte layer is a sealed film primary battery, characterized in that consisting of a mixture of a water-soluble polymer, an aqueous electrolyte solution and hydrophilic fine particles. The method of claim 8, The hydrophilic fine particles are sealed film primary battery, characterized in that consisting of silica, talc, alumina (Al ₂ O ₃ ), titania (TiO ₂ ), clay (zeolite), zeolite, polyethyleneimine, ethylene glycol, or polyethylene glycol. With the anode, With a cathode, Separation membrane made of a thin film formed with a plurality of through-holes formed in a uniform shape so as to extend in parallel with each other and a predetermined distance between them between the anode and the cathode and have an opening width of 10 μm to 2 mm, respectively. and, A non-flowable electrolyte layer filled in the space between the positive electrode and the negative electrode, The separator extends in a thickness of a first size between the anode and the cathode, and each of the plurality of through holes has an opening width of a second size larger than the first size, The electrolyte layer includes a first electrolyte layer extending in parallel with the anode between the anode and the separator, a second electrolyte layer extending in parallel with the cathode between the cathode and the separator; The sealed film primary battery comprising a plurality of third electrolyte layers filling the inside of the through hole of the separator so as to be integrally connected to the first electrolyte layer and the second electrolyte layer, respectively. With the anode, With a cathode, A separator formed of a non-porous thin film having a plurality of through-holes extending in parallel with each other and spaced apart from each other by a predetermined distance between the anode and the cathode and having an opening width of 10 μm to 2 mm, respectively; A non-flowable electrolyte layer filled in the space between the positive electrode and the negative electrode, The separator extends in a thickness of a first size between the anode and the cathode, and each of the plurality of through holes has an opening width of a second size larger than the first size, The electrolyte layer includes a first electrolyte layer extending in parallel with the anode between the anode and the separator, a second electrolyte layer extending in parallel with the cathode between the cathode and the separator; The sealed film primary battery comprising a plurality of third electrolyte layers filling the inside of the through hole of the separator so as to be integrally connected to the first electrolyte layer and the second electrolyte layer, respectively.

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