KR100824869B1 - Lithium polymer battery of method for manufacturing and lithium polymer battery - Google Patents

Abstract

A method for preparing a lithium polymer battery, and a lithium polymer battery prepared by the method are provided to improve the productivity, to lower the manufacturing cost and to enhance the characteristics of an electrode assembly irrespective of the kind of a case material. A method for preparing a lithium polymer battery comprises the steps of: putting a plurality of electrode assemblies in a container and (S1) injecting an electrolyte solution into the container; (S2) infiltrating the plurality of electrode assemblies accommodated in the container; (S3) applying pressure to the plurality of electrode assemblies infiltrated with an electrolyte solution; (S4) applying electric power to the positive electrode tap and the negative electrode tap of the plurality of electrode assemblies to charge it; and (S5) curing the plurality of electrode assemblies.

Description

TECHNICAL FIELD OF THE INVENTION A lithium polymer battery and a method of manufacturing a lithium polymer battery {LITHIUM POLYMER BATTERY OF METHOD FOR MANUFACTURING AND LITHIUM POLYMER BATTERY}

1 is a perspective view of an electrode assembly used in the lithium polymer battery manufacturing method according to the present invention.

2 is a flowchart illustrating a method of manufacturing a lithium polymer battery according to an embodiment of the present invention.

3A is a perspective view of a state in which a plurality of electrode assemblies are accommodated in a container according to an embodiment of the present invention.

3B is a perspective view of a state in which a plurality of electrode assemblies are accommodated in a container and pressurized according to an embodiment of the present invention.

3C is a perspective view of a state in which a plurality of electrode assemblies accommodated in a container according to an embodiment of the present invention have a positive / cathode power applied thereto.

4 is a flowchart illustrating a method of manufacturing a lithium polymer battery according to another embodiment of the present invention.

5 is an exploded perspective view of a pouch-type lithium polymer battery prepared by a lithium polymer battery manufacturing method according to another embodiment of the present invention.

6 is an exploded perspective view of a can-type lithium polymer battery manufactured using a method of manufacturing a lithium polymer battery according to another embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

100; Electrode assembly 110; Positive plate

120; Negative electrode plate 130; Separator

140; Positive electrode tab 150; Negative electrode tab

160; Insulation Tape

200; Container 210; Platen

220; Anode power supply 230; Cathode power

300; Pouch 310; Top film

320; Bottom layer 321; Accommodation home

322; Heat fusion site 400; Cans

500; Cap assembly 600; case

The present invention relates to a method for producing a lithium polymer battery, and more particularly, to a method for producing a lithium polymer battery having a chemical polymer electrolyte using a monomer.

As the polymer electrolyte used for the polymer lithium secondary battery, two types are known, a physical polymer type and a chemical polymer type. The physical polymer type differs in that the polymer polymerized beforehand is used as the starting material, whereas the chemical polymer type uses unpolymerized monomer or oligomer as the starting material and polymerizes them together with the non-aqueous electrolyte. In other words, the physical polymer polymer electrolyte is prepared by dissolving a polymer as a raw material in a solvent to prepare a solution, applying the solution to a positive electrode or a negative electrode, and then removing the solvent to form a polymer-electrode composite. It is formed by impregnating a nonaqueous electrolyte in the electrode composite. On the other hand, the chemical polymer electrolyte comprises a positive electrode and a negative electrode in advance, and after adding a mixed solution of a monomer or oligomer and a non-aqueous electrolyte as a raw material to the positive electrode and the negative electrode, the monomer or oligomer is polymerized by thermal polymerization or the like. Is formed.

In the manufacturing process of a lithium polymer battery having a chemical polymer electrolyte using a monomer among such polymer electrolytes, first, a positive electrode plate, a negative electrode plate, and a separator are stacked, and then wound to form an electrode assembly. Then, after the electrode assembly is inserted into the container of the pouch or can, the mixed solution of the monomer or oligomer and the non-aqueous electrolyte is injected. Then, the pouch or can is temporarily sealed to seal the electrode assembly, and then curing is performed to polymerize the monomer by chemical reaction. Then, the electrode assembly accommodated in the pouch or can is filled to remove the gas discharged with impurities, and finally the opening of the pouch or can is sealed to form a lithium polymer battery.

However, the processes performed after the electrode assembly is taken are limited to shorten the manufacturing time of the lithium polymer battery since the process is sequentially performed after accommodating one electrode assembly in a pouch or a can.

In addition, since the electrode assembly is placed in the pouch, the process proceeds within the range that does not impair the characteristics of the pouch. However, even though there is a method of improving the characteristics of the electrode assembly, the characteristics of the pouch are changed. There is a problem that another process is added because it cannot be used to improve the characteristics of the pouch, or to proceed in consideration of changing the characteristics of the pouch.

In addition, in order to proceed with the process of improving the characteristics of the electrode assembly, the pouch must be designed according to the process of improving the characteristics of the electrode assembly, so that the material of the pouch becomes complicated, the unit cost increases, and the process becomes complicated. Occurs. For example, when initially charging the electrode assembly temporarily sealed in the pouch, since the electrode assembly generates gas and swells, a gas chamber is formed in the pouch to induce the gas generated at the initial charge into the gas chamber, It is necessary to remove and finally seal the electrode assembly with a pouch. In addition, the pressing process of adhering the positive / negative plate and the polymer electrolyte to improve ion conductivity is possible after the pouch is a flexible case, but there is a problem that it is difficult to carry out when the rectangular can is used as the case.

Technical problem of the present invention to solve the above problems is

Firstly, an object of the present invention is to improve the productivity of a lithium polymer battery by adjusting a manufacturing processor of the lithium polymer battery.

Second, the purpose is to reduce the manufacturing process of the lithium polymer battery, thereby reducing the cost of the manufacturing process.

Thirdly, the purpose of the case used in the lithium polymer battery is not limited by the conditions of the lithium polymer battery manufacturing process, and only the characteristics of the case can be designed to be designed.

Fourthly, when the process of improving the characteristics of the electrode assembly, the purpose of the process to improve the characteristics of the electrode assembly regardless of the material of the case.

A method of manufacturing a battery of a lithium polymer of the present invention for achieving the above object includes an electrolyte solution pouring step of placing a plurality of electrode assemblies in a container, and injecting the electrolyte solution in the container; An electrode assembly impregnation step of impregnating a plurality of electrode assemblies accommodated in the container; An electrode assembly pressurizing step of applying pressure to a plurality of electrode assemblies impregnated with the electrolyte solution; An initial stage of charging of the electrode assembly in which the positive electrode tab and the negative electrode tab provided in the plurality of electrode assemblies impregnated with electrolyte are charged by applying power; And an electrode assembly curing step of curing the plurality of electrode assemblies impregnated with the electrolyte.

In addition, the electrode assembly initial charging step may proceed in a vacuum atmosphere.

In addition, the electrode assembly pressing step may press the plurality of electrode assemblies by mechanically pressing.

In addition, the pressing of the electrode assembly may press the plurality of electrode assemblies by putting the plurality of electrode assemblies in a pressure chamber and increasing the internal pressure of the pressure chamber.

In addition, the electrode assembly curing step may be performed at a temperature of 60 ° C. to 80 ° C., and a curing time of 2 hours to 4 hours.

In addition, the electrode assembly curing step may be performed in an inert gas atmosphere.

In addition, the electrode assembly curing step may be performed after the electrode assembly impregnation step.

The electrode assembly may be placed in a pressure chamber, and the electrode assembly pressurization step, the initial charging step of the electrode assembly, and the electrode assembly curing step may be performed in the pressure chamber.

In addition, the electrode assembly may be placed in a pressure chamber, and the electrode assembly may be pressed in the pressure chamber and the electrode assembly initial charging step may be performed.

The electrode assembly may further include an electrode assembly pouch sealing step of sealing the pouch by accommodating the electrode assembly in the pouch after the curing of the electrode assembly.

On the other hand, the lithium polymer battery according to the present invention comprises an electrode assembly comprising a chemical polymer polymer electrolyte; And a case accommodating the electrode assembly, wherein the chemical polymer electrolyte is formed inside the electrode assembly.

In this case, the case may be a rectangular or cylindrical can.

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

First, the electrode assembly to be manufactured by the lithium polymer battery manufacturing method of the present invention will be described with reference to FIG. 1. The electrode assembly 100 includes a positive electrode plate 110, a negative electrode plate 120, and a separator 130. Can be formed.

The positive electrode plate 110 includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer may be formed of a layered compound containing lithium, a binder to improve bonding strength, and a conductive material to improve conductivity. As the positive electrode current collector, aluminum is generally used, and the positive electrode current collector becomes a passage for the charge generated in the positive electrode active material layer and serves to support the positive electrode active material layer. The positive electrode active material layer is attached to the wide surfaces of the positive electrode current collector, and a positive electrode non-coating portion (not shown) is formed at one end of the positive electrode plate in which the positive electrode active material layer is not formed. The positive electrode tab 140 is bonded to the positive electrode non-coating portion.

The negative electrode plate 120 includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer may be formed of a binder that contains carbon and improves the bonding force between hard carbon, which is commonly used, or graphite and active material particles. As the negative electrode current collector, copper is generally used, and the negative electrode current collector serves as a movement path of charge generated in the negative electrode active material layer, and serves to support the negative electrode active material layer. The negative electrode active material layer is formed on a wide surface of the negative electrode plate 120, wherein a negative electrode non-coating portion (not shown) is formed at one end of the negative electrode plate 120. The negative electrode tab 150 is bonded to the negative electrode non-coating portion.

The separator 130 is interposed between the positive electrode plate 110 and the negative electrode plate 120 to insulate the positive electrode plate 110 and the negative electrode plate 120 and allow charges of the positive electrode plate 110 and the negative electrode plate 120 to pass therethrough. Generally, the material of the separator 130 is polyethylene (PE) or polypropylene (PP), but the material is not limited thereto.

Referring to Figure 2 with respect to the lithium polymer battery manufacturing method according to the present invention, the lithium polymer battery manufacturing method of the electrolyte injection step (S1), electrode assembly impregnation step (S2), electrode assembly pressurization step (S3) and the electrode assembly initial It may be formed including a charging step (S4), and an electrode assembly curing step (S5).

Referring to FIG. 3A, in the electrolyte injection step S1, a plurality of electrode assemblies 100 are placed in a container, and an electrolyte solution is poured into a container 200 in which the plurality of electrode assemblies 100 are accommodated. In this case, the electrolyte may be an electrolyte for a chemical polymer battery in which an initiator is added to a monomer. In addition, the electrolyte injection step (S1) may be performed in a dry state without moisture in consideration of the reactivity of the electrolyte and moisture.

Then, in the electrode assembly impregnation step (S2), the electrode assembly 100 is left for 12 hours to 80 hours to impregnate the electrolyte in the electrode assembly 100 in the separator.

Referring to FIG. 3B, the electrode assembly pressing step S3 pressurizes the electrode assembly 100 by applying pressure to the plurality of electrode assemblies 100. As a method of pressing the electrode assembly 100, there is a method of mechanically compressing it. Referring to FIG. 3B, a plurality of electrode assemblies 100 are simultaneously applied to both sides of the plurality of electrode assemblies 100 in a wide form at a time. Make. At this time, the positive electrode plate and the negative electrode plate and the separator of the electrode assembly 100 is very densely spaced by the electrode assembly pressing step (S3). Meanwhile, the method of pressing the plurality of electrode assemblies 100 may be formed in various ways without being limited to the method of using the pressure plate 210 shown in the drawing. As another method, the plurality of electrode assemblies 100 may be formed. Into the pressure chamber (not shown), the internal pressure of the pressure chamber may be increased to pressurize the plurality of electrode assemblies 100. At this time, the method of mechanically compressing and the method of increasing the internal pressure in the pressure chamber may proceed simultaneously.

Referring to FIG. 3C, in the initial stage charging of the electrode assembly S4, the power supply 220 of the positive electrode is applied to the positive electrode tab 140 provided in the plurality of electrode assemblies 100 accommodated in the container, and the negative electrode tab 150 is applied to the positive electrode tab 140. The electrode assembly 100 is charged by applying a negative power. In this case, the electrode assemblies 100 are discharged from the gas remaining in the pores of the separator by the electrode assembly initial charging step S4 in the state in which the electrode assemblies are pressurized by the electrode assembly pressurizing step S3, and at the same time, impurities are decomposed. Will be discharged. At this time, the electrode assembly initial charging step (S4) may proceed in a vacuum atmosphere to efficiently remove the gas generated in the electrode assembly (100).

Finally, the electrode assembly curing step (S5) is to cure the electrode assembly 100, the curing is a process of polymerizing the electrolyte of the monomer, the electrode assembly 100 of about 60 ℃ to 80 ℃ range The temperature is maintained and left for about 2 to 5 hours. In this case, the electrode assemblies 100 may be processed in an atmosphere in which an inert gas is formed so as not to contact with oxygen to cause a chemical reaction. After this curing step (S5), the electrolyte of the monomer impregnated in the electrode assembly 100 is polymerized.

In addition, the electrode assembly curing step (S5) may proceed immediately after the electrode assembly impregnation step (S2). That is, the electrode assembly pressing step (S3) and the electrode assembly initial charging step (S4) during the process of the electrode assembly curing step (S5), or may proceed before or after these processes.

Using these steps (S1, S2, S3, S4, S5), unlike the conventional manufacturing method in which one electrode assembly is inserted into one pouch or can, the electrolyte is injected and sealed into the pouch or can. The process from the electrolyte injection step S1 to the electrode assembly curing step S5 may be applied to the plurality of electrode assemblies 100 at the same time, thereby improving the yield of the lithium polymer battery.

In addition, the electrode assembly 100 is placed in a pressure chamber (not shown) and the electrode assembly pressurizing step (S3), the electrode assembly initial charging step (S4) and the electrode assembly curing step (S5) at the same time in the pressure chamber You can proceed. At this time, the pressure chamber used is a pressure regulator for controlling the pressure inside, an electrode assembly filling device for filling the electrode assembly, a gas supply device for supplying gas into the pressure chamber, the gas inside the pressure chamber by suction And a gas discharge device for discharging, a temperature control device for controlling a temperature inside the pressure chamber, a heating device for supplying heat to the pressure chamber, and a humidity measuring device for measuring humidity in the pressure chamber. By selectively using the device, the process from the electrode assembly pressing step S3 to the electrode assembly curing step S5 can be performed in one pressure chamber, thereby improving manufacturing efficiency. In addition, the degree of contamination of the electrode assembly 100 may be reduced by blocking the electrolyte from the air to prevent contamination from moisture contained in the air of the electrolyte in one chamber.

In addition, the electrode assembly 100 is placed in a pressure chamber, and the electrode assembly pressurizing step S3 and the electrode assembly initial charging step S4 are performed in the pressure chamber, and then the electrode assembly curing step S5 is performed in a separate chamber. In addition, the electrode assembly curing step (S5) may proceed first, and then the electrode assembly pressurization step (S3), and the electrode assembly initial charging step (S4) may be performed.

In addition, the electrode assembly having passed through these steps (S1, S2, S3, S4, S5) may be formed in a pouch, and with reference to FIG. 4, the lithium polymer battery manufacturing method includes an electrode assembly pouch sealing step (S6). It may be formed to further include.

Referring to FIG. 5, the electrode assembly pouch sealing step (S6) is a pouch 300 after receiving the respective electrode assemblies through the steps S1, S2, S3, S4, and S5 individually into the pouch 300. ) Can be sealed. First, the pouch 300 may be formed of a lower layer 320 having the receiving groove 321 and an upper layer 310 covering the opening of the lower layer 320. After receiving the electrode assembly 100 in the lower layer 320 having the receiving groove 321, the opening of the lower layer 320 is covered with the upper layer 310. Thereafter, the portion 322 where the upper layer 310 and the lower layer 320 of the pouch 300 come into contact with each other is sealed by heat fusion or adhesion to complete a pouch-type lithium polymer battery. In this case, the portion where the positive electrode tab 140 and the negative electrode tab 150 contact the pouch 300 may be insulated by the insulating tape 160. The pouch 300 used in this process is selected without considering the process from the electrolyte injection step (S1) to the electrode assembly curing step (S5), considering only the process of the pouch receiving step (S6) to select the material and structure. If so, it can be formed of various materials and configurations. For example, the pouch in the form of a multilayer film used in a conventional pouch has an inner layer formed of a heat-adhesive layer made of CPP (Casted Polypropylene), an intermediate barrier layer formed of an aluminum layer, and an outer protective film formed of a nylon layer. Has been used. Since the conventional multilayer film material is formed of the material and the structure in consideration of the conventional process, there is a limit in selecting the intermediate bare layer and the outer protective film. However, according to the present invention, since the material and structure of the pouch 300 do not have to be greatly considered in the process up to the electrolyte injection step (S1) and the electrode assembly curing step (S5), various materials than the pouches used in the conventional method. A pouch-type lithium polymer battery may be manufactured using a pouch having a constitution.

Referring to FIG. 6, the lithium polymer battery according to the present invention may include an electrode assembly 100 and a case 600 accommodating the electrode assembly 100. Such a case 600 may be formed of a can-shaped case illustrated in FIG. 6, or may be formed of a pouch-shaped case illustrated in FIG. 5.

As shown in FIG. 2, the electrode assembly 100 includes an electrolyte injection step (S1), an electrode assembly impregnation step (S2), an electrode assembly pressurization step (S3), an electrode assembly initial charging step (S4), and an electrode. Through an assembly curing step (S5) is an electrode assembly containing a chemical polymer electrolyte. Such an electrode assembly has been described above, and thus description thereof will not be repeated.

Referring to FIG. 6, the case 600 may include a can 400 and a cap assembly 500.

First, the shape of the can 400 may be formed in the shape of a square or track shape in consideration of the shape of the electrode assembly 100. In addition, according to the shape of the can 400, the shape of the case 600 may also be formed in a square or track shape. The can 400 having such a shape accommodates the insulating case 560 on the electrode assembly 100, covers the opening of the can 400 with the cap plate 560, and is coupled by a welding method. The material of the can 400 may be mainly aluminum, but the material of the can 400 is not limited thereto.

The cap assembly 500 may include a cap plate 510, an electrode terminal 520, an insulating gasket 530, an insulating case 560, a terminal plate 540, and an insulating plate 550. First, the cap plate 510 is electrically connected to the positive electrode tab 140 and closes the opening of the can 400. In addition, a safety vent 513 may be formed on an upper surface of the cap plate 510. When the opening of the can 400 containing the electrode assembly 100 is closed with the cap plate 510, the can The safety vent 513 may be opened at the internal pressure increase of the 400 to prevent an explosion of the can 400. Meanwhile, the electrode terminal 520 is seated in the central hole of the cap plate 510 and the cap plate 510 and is electrically connected to the negative electrode tab 150. The insulating gasket 530 surrounds the body of the electrode terminal 520 to insulate the electrode terminal 520 from the cap plate 510. The insulating case 560 includes a hole through which the positive electrode tab 140 and the negative electrode tab 150 pass, and is seated on the electrode assembly 100 to insulate the upper surface of the electrode assembly 100. The terminal plate 540 provides a hole for pressing and fixing the end of the electrode terminal 520. The insulation plate 550 insulates the terminal plate 540 from the cap plate 510. The insulating gasket 530, the insulating case 560, and the insulating plate 550 may be formed of an insulating material such as polypropylene resin or polyethylene resin, and the electrode terminal 520), the cap plate 510, and the terminal. The plate 540 may be formed of a conductive metal material such as aluminum or an alloy containing aluminum or an alloy containing nickel or nickel. At this time, the cap assembly 500 is not limited to the illustrated shape or the above description, and the positive electrode tab 140 and the positive electrode tab 140 of the electrode assembly 100 are not shorted with each other. The cathode of the cathode and the cathode tab 150 may be formed in a structure that can be connected to an external device. In FIG. 6, the positive electrode tab 140 is electrically connected to the can 400 and the cap plate 510 to form a positive electrode, and the negative electrode tab 150 is electrically connected to the electrode terminal 520 to form a negative electrode.

The electrode assembly 100 accommodated in the lithium secondary battery as described above is a process from the electrolyte injection step (S1) to the electrode assembly curing step (S5) to form a chemical polymer electrolyte inside the electrode assembly 100 Therefore, without additional electrolyte injection, it can be used immediately sealed with the case 600. In this case, in consideration of the lifespan, charging / discharging efficiency, stability, etc. of the electrode assembly 100, an extra electrolyte may be further accommodated inside the can 400 in which the electrode assembly 100 is accommodated.

It will be appreciated that the electrode assembly prepared according to the present invention can be used not only in the pouch type lithium polymer battery described above, but also in the can type lithium polymer battery. Accordingly, the present invention as described above is not limited to the technical spirit of the above-described specific embodiments or the drawings, and the ordinary skill in the art to which the invention belongs without departing from the spirit of the invention claimed in the claims. Anyone skilled in the art can make various modifications, as well as such changes within the scope of the present invention.

The lithium polymer battery manufacturing method of the present invention has the effect of first improving the productivity of the lithium polymer battery by changing the manufacturing process of the lithium polymer battery.

Secondly, the manufacturing process of the lithium polymer battery is reduced, thereby reducing the cost of the manufacturing process.

Third, the case used for the lithium polymer battery is not limited by the conditions of the lithium polymer battery manufacturing process, so that the case can be designed, there is an effect that a wide range of case selection to select a variety of cases.

Fourth, when proceeding to improve the characteristics of the electrode assembly, there is an effect that can improve the characteristics of the electrode assembly regardless of the material of the case.

Claims (12)

An electrolyte injection step of placing a plurality of electrode assemblies in a container and injecting an electrolyte solution into the container; An electrode assembly impregnation step of impregnating a plurality of electrode assemblies accommodated in the container; An electrode assembly pressurizing step of applying pressure to a plurality of electrode assemblies impregnated with the electrolyte solution; An initial stage of charging of the electrode assembly in which the positive electrode tab and the negative electrode tab provided in the plurality of electrode assemblies impregnated with the electrolyte are charged by applying power; And And an electrode assembly curing step of curing the plurality of electrode assemblies in which the electrolyte is impregnated. The method of claim 1, The initial charging step of the electrode assembly A process for producing a lithium polymer battery, characterized by advancing in a vacuum atmosphere. The method of claim 1, The electrode assembly pressing step is a method of manufacturing a lithium polymer battery, characterized in that the pressing by pressing the plurality of electrode assemblies mechanically. The method of claim 1, In the pressing step of the electrode assembly, the plurality of electrode assemblies are placed in a pressure chamber, and the internal pressure of the pressure chamber is increased to press the plurality of electrode assemblies. The method of claim 1, The electrode assembly curing step The process for producing a lithium polymer battery, characterized in that the temperature is 60 ℃ to 80 ℃, the curing time is carried out in a state of 2 hours to 4 hours. The method of claim 5, wherein The electrode assembly curing step A process for producing a lithium polymer battery, characterized by advancing in an inert gas atmosphere. The method of claim 1, Wherein the electrode assembly curing step is performed after the electrode assembly impregnation step. The method of claim 1, The electrode assembly is placed in a pressure chamber and the electrode assembly is pressed in the pressure chamber, the electrode assembly initial charging step, the electrode assembly curing method characterized in that the electrode assembly curing step. The method of claim 1, The electrode assembly is placed in a pressure chamber and the electrode assembly in the pressure chamber, the method of manufacturing a lithium polymer battery, characterized in that for performing the electrode assembly initial charging step. The method of claim 1, After the electrode assembly curing step, the electrode assembly is a manufacturing method of a lithium polymer battery further comprising the electrode assembly pouch sealing step of sealing the pouch by receiving the electrode assembly in the pouch. An electrode assembly comprising a chemical polymer electrolyte; And It includes a case for receiving the electrode assembly, And the chemical polymer electrolyte is formed only inside the electrode assembly. The method of claim 11, The case is a lithium polymer battery, characterized in that the rectangular or cylindrical can.

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