KR100818206B1 - Method of making battery using as case with aluminium foil - Google Patents

Abstract

The present invention seals after receiving a wound or stacked electrode assembly consisting of a cathode, a separator, a cathode in an exterior formed of aluminum foil, the aluminum foil is used as the inner surface of the battery exterior, or bent independently to the exterior of the battery The present invention relates to a battery manufacturing method using an aluminum foil having improved safety and energy density as a case.

Battery, Aluminum, Case, Inner Tube, Exterior, Inside, Pouch, Energy, Density, Stability

Description

Manufacturing method of battery using aluminum foil as a case {METHOD OF MAKING BATTERY USING AS CASE WITH ALUMINIUM FOIL}

1 is a perspective view showing an electrode assembly including a winding shaft according to the present invention.

2 (a) to 2 (e) are perspective views showing an electrode assembly according to the present invention.

3 is a flowchart sequentially showing a method for manufacturing a battery having the aluminum foil according to the present invention as an appearance of the battery.

4 is a cross-sectional view showing an aluminum foil used for the appearance of a battery according to the present invention.

5 is a cross-sectional view showing the aluminum foil used for the inner surface of the battery appearance according to the present invention.

Figure 6 is a side view showing a two-stage bent cylindrical battery according to the present invention.

Figure 7 is a front view showing the finish of the cylindrical battery according to Figure 5 of the present invention.

8 is a flowchart sequentially illustrating a secondary sealing process added when an aluminum foil according to the present invention is used as an inner surface of a battery.

9 is a side view showing a cylindrical battery subjected to one-stage bending when the aluminum foil according to the present invention is used as an inner surface of a battery appearance;

10 is a potential capacity graph of the AAA size cylindrical battery manufactured according to Example 1 of the present invention.

Description of the main symbols in the drawings

1 electrode assembly 2 terminal 3 binding polymer

4: aluminum foil 41: finish 5: heat shrinkable tube

The present invention seals after receiving a wound or stacked electrode assembly consisting of a cathode, a separator, a cathode in an exterior formed of aluminum foil, the aluminum foil is used as the inner surface of the battery exterior, or bent independently to the exterior of the battery The present invention relates to a battery manufacturing method using an aluminum foil having improved safety and energy density as a case.

Generally, batteries are classified into primary batteries and secondary batteries. Primary batteries are mostly cylindrical batteries, and secondary batteries are made of cylindrical batteries and rectangular batteries. The square battery uses a metal can or pouch as an exterior material, and a battery using the pouch is called a pouch type battery.

The cylindrical and canned rectangular batteries are composed of cans and cap assemblies, and the cans of the cylindrical and rectangular batteries are made of stainless steel or aluminum.

In general, the cylindrical battery is manufactured in the form of a winding or rod of a cathode, a separator, and a cathode, a process of injecting an electrode assembly into a cylindrical can and injecting an electrolyte solution, and a terminal or a rod attached to a cathode and an anode. It is manufactured through the process of connecting to the cap assembly and the cylindrical can, and the beading and creeping process to strongly connect the cap assembly and the cylindrical can.

The fabrication of the rectangular battery generally includes a process of fabricating a cathode or separator electrode, a wound or stacked electrode assembly of a cathode, inserting an electrode assembly into a rectangular can, connecting a terminal to a cap assembly, and injecting and sealing an electrolyte. Manufactured through the process.

In particular, the manufacturing process of the lithium-based cylindrical and rectangular secondary battery is going through a more complicated process, such as the configuration of the cap assembly and welding the terminals attached to the negative and positive electrode to the cap assembly and the cylindrical can.

However, such a conventional manufacturing method has a problem in that sacrifice of energy density per weight and volume occurs due to the weight of the can and the consumption of the cap portion, and it is difficult to manufacture various types of batteries other than square and cylindrical shapes.

In the case of the pouch-type square secondary battery, the electrode assembly is generally manufactured by winding or stacking a negative electrode, a separator, and a positive electrode, and then, the electrode assembly is deeply drawn and inserted into a square groove formed in a case, followed by injection of an electrolyte solution. And, it is manufactured through the process of vacuum sealing while heat-sealing the terminal and the case, it is difficult to manufacture the shape of the square and must be vacuum sealed in order to apply a constant pressure to the electrode assembly, in order to deep draw the case by applying a constant pressure Since the grooves must be formed, the case must be formed to a certain thickness, and the deeper the drawing depth, the more technically difficult it is to make the grooves.

In order to solve the above problems, in the present invention, by using the aluminum foil independently as the appearance of the battery or as the inner surface of the battery, by providing a battery manufacturing method having a variety of forms of improved energy density and safety in a simple manufacturing process For that purpose.

In order to achieve the above object, the present invention is an electrode assembly manufacturing step consisting of winding or laminating an electrode layer consisting of a cathode, an anode and a separator positioned between the cathode and the anode;

An electrolyte injection step of injecting an electrolyte solution into the electrode assembly;

Sealing step of sealing the electrode assembly in which the electrolyte is injected;

In the sealing step, the electrode assembly is wound with an aluminum foil and accommodated therein, and after the finish of the wound aluminum foil is bound with a binding polymer, a terminal protruding to one or both sides of the electrode assembly, and the aluminum The manufacturing method of the battery using the foil and the aluminum foil which heat-fused at 100-250 degreeC simultaneously at the said binder polymer as a case is made into the main structure.

The case refers to an aluminum foil used independently as an exterior of a battery or used on an inner surface of an exterior made of another material.

When the aluminum foil is used on the inner surface of the outer appearance, the outer appearance may be at least one selected from polyolefin, pouch, heat shrinkable tube, polyethylene terephthalate (PET), polyimide (PI), and polyvinyl chloride (PVC). Although it does not restrict | limit a material in particular, The thickness of the aluminum foil used for the inner surface of an external appearance is 10-100 micrometers.

The electrode assembly has a form of any one selected from cylindrical and polygonal.

The binder polymer is polyolefin-based, polyimide (PI), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene terephthalate (PET) Any one selected from the group consisting of one or a mixture of two or more may be used as a single layer or multiple layers, characterized in that the binding to the terminal formed on one side or both sides of the electrode assembly at 50 ~ 200 ℃.

Hereinafter, the above configuration will be described in more detail with reference to the accompanying drawings.

The method of manufacturing a battery according to the present invention is prepared through an electrode assembly manufacturing step, an electrolyte injection step, and a sealing step, and the following steps will be described sequentially from the electrode assembly manufacturing step.

Electrode Assembly Manufacturing Step

The electrode assembly 1 shown in FIG. 1 has a form in which a cathode, a separator, and an anode are wound (a to d) and stacked (e) as shown in FIG. 2, and the electrode assembly 1 has a form. Is various, can be manufactured and used in a variety of desired shapes, such as oval in addition to the polygonal column (a ~ b) rectangular column (c ~ e) configured by winding or laminated, which is a conventional exterior material It is possible to use aluminum foil instead of metal (aluminum, stainless steel) or pouches.

As shown in FIG. 1, the wound electrode assembly has a cylindrical shape that is completed by winding the electrode layer on the winding shaft 100 and then leaving the winding shaft 100. The stacked electrode assembly is illustrated in FIG. 2. As shown in e, the electrode layer is completed by laminating.

Electrolyte injection and Immersion stage

Immersion of the electrode assembly configured as described above or injecting the electrolyte, or the injection of the electrolyte, the injection of the electrolyte may be carried out after receiving the electrode assembly with an aluminum foil to be described later and the binding treatment.

Seal step

As illustrated in FIG. 3, the electrode assembly 1 that has undergone the electrolyte injection or immersion step is wound around the aluminum foil 4 to form a cylindrical tube to form the electrode assembly 1 therein. And heat-sealing the finish portion 41 of the aluminum foil 4 containing the electrode assembly 1, and one end and the other end of the cylindrical tube formed of the aluminum foil 4, at the center of the cylindrical tube. It extends in the outward direction and expands, and expands and expands the aluminum foil 4 and the terminal 2 and the binder polymer 3 extending to one side or both sides of the electrode assembly at the same time and heat-sealed.

The aluminum foil 4 has a thickness of 10 ~ 100㎛, as shown in Figure 4, is formed by binding the binding polymer (3) to the outer circumference.

When the thickness of the aluminum foil 4 is 10 μm or less, the aluminum foil 4 has a problem of being easily torn and damaged, and when the thickness of the aluminum foil 4 is 100 μm or more, it is difficult to achieve the effect of the present invention for improving the energy density. It is preferred to have a thickness of 10 to 100 µm.

The binding by the binding polymer (3) is to enhance the binding force with the terminal flowing out from the negative electrode and the positive electrode to the electron conductor and to give an insulation effect, when the binding temperature is 50 ℃ or less, the binding polymer (3) ), The binding polymer (3) is melted in the temperature range of 50 to 200 ℃ because the binding polymer (3) is melted and non-uniform binding occurs when the binding polymer (3) is melted. It is preferable.

The thermal fusion is performed by the terminal 2, the binding polymer 3 and the aluminum foil (4) at a temperature of 100 ~ 250 ℃ at the same time, when the thermal fusion temperature is 100 ℃ or less, the binding site is weak even heat When the falling problem occurs, and the resin and the binding polymer (3) is difficult to maintain the shape in the case of 250 ℃ or more, it is preferable to perform thermal fusion in the temperature range of 100 ~ 250 ℃.

In addition, the sealing polymer 3 may be heat-sealed to seal the cylinder of the aluminum foil 4 by heat-sealing while vacuuming the inside of the battery at a temperature of 100 to 250 ° C. using a vacuum packaging machine.

The electrolyte injection and sealing process may be performed in a controlled atmosphere (inert gas filling box, dry room) when it is necessary to suppress the reaction with moisture.

Terminal Bending

When the aluminum foil 4 is independently used as a battery appearance, the binding portion between the terminal 2 and the aluminum foil 4 extending to one side or both sides of the battery completely formed and sealed has a problem of lowering the energy density. do.

In order to solve the above problem, as illustrated in FIG. 6, the terminal 2 extending to one side or both sides of the battery is bent in two stages using a bending machine.

6 is a side view showing a two-stage bent cylindrical battery according to the present invention, Figure 7 is a front view showing the finish of the cylindrical battery according to Figure 6 in the direction of the arrow.

Unlike the above, when the aluminum foil 4 is used on the inner surface of the battery exterior, as described later, the aluminum foil 4 is subjected to the secondary sealing step without the bending process.

Accordingly, the terminal may be bent to solve the problem of lowering the energy density, but may be omitted in consideration of connectivity with a battery-applied device.

2nd seal step

When the aluminum foil 4 is used on the inner surface of the cell appearance, it is distinguished from when the aluminum foil 4 is used for the appearance independently.

As shown in FIG. 5, the binding polymer 3 is bound to the outer surface of the aluminum foil 4, and the binding polymer 3 is also bound to the other surface of the aluminum foil 4. In other words, the binding polymer 3 is bound to both sides of the aluminum foil 4, and as shown in FIG. 9, the bending treatment is performed in one stage.

As shown in FIG. 8, when the secondary sealing step is sequentially viewed based on the left side, the inner surface of the battery is sealed with the aluminum foil 4, so that the sealed portion of the sealed battery does not protrude to the outside. After finishing, the finished cell is accommodated in a heat shrinkable tube (5), heat is applied to the heat shrinkable tube (5) at a temperature of 100 ~ 250 ℃ to induce shrinkage, and then the heat shrinkable tube (5) and By heat-sealing the aluminum foil 4 and the binding polymer 3 bound to both sides of the aluminum foil 4 at a temperature of 100 to 250 ° C., the secondary sealing step is completed.

If the thermal fusion temperature is less than 100 ℃ causes a problem that the binding site is falling even in weak heat, when the temperature is 250 ℃ or more because the resin and the binding polymer (3) is difficult to maintain the shape of the fusion temperature Is preferably fused in the temperature range of 100 ~ 250 ℃.

The heat-shrinkable tube 5 is a component that does not react with the electrolyte, and used any one or a mixture of two or more selected from polyolefin, polyester, polyvinyl chloride, and silicone resin, and the shrinkage ratio is 1% or more. It can be used regardless of the manufacturing method. When the shrinkage rate is 1% or less, it is difficult for the heat shrink tube to maintain the proper pressure and an empty space is likely to occur.

The diameter before shrinking of the heat shrinkable tube 5 should be larger than the size of the battery using the aluminum foil 4 as the inner surface of the outer tube and the maximum shrinkage diameter should be smaller than the size of the battery using the aluminum foil 4 as the inner surface of the tube. .

If the diameter before shrinkage is smaller than the size of the battery using the aluminum foil 4 as the inner surface of the exterior, the battery using the aluminum foil 4 as the inner surface of the exterior cannot be accommodated. If 4) is larger than the size of the battery used as the inner surface of the exterior, proper pressure cannot be applied to the battery, and it is difficult to form a desired shape due to empty space.

The method of sealing the battery using the aluminum foil (4) as the inner surface by heat-sealing the binding polymer (3) to be sealed by heat sealing while vacuuming the inside of the battery at a temperature of 100 ~ 250 ℃ using a vacuum packaging machine It may be.

The electrolyte injection and sealing process may be performed in a controlled atmosphere (inert gas filling box, dry room) when it is necessary to suppress the reaction with moisture.

The battery described above is an example of a cylindrical battery. For the use of the aluminum foil 4 as an external appearance of the battery, a winding type having a cylinder or a square shape having a terminal on one side or both sides is used. ,

As the aluminum foil 4 is used for the inner surface of a battery using a shrinkable tube as an external appearance, a wound type having a cylinder or a square shape and having a terminal on one side or both sides is used. It is to be understood that is a variety of manufacturing.

The configuration of the present invention as described above will be described in more detail through the first embodiment.

Example 1: Aluminum Foil as Appearance Lithium ion  Fabrication of batteries

Graphite is used as the negative electrode active material, copper foil is used as the negative electrode plate, lithium cobalt oxide (LiCoO ₂ ) is used as the positive electrode plate, and aluminum foil is used as the positive electrode and the positive electrode, respectively. It was produced by. The negative electrode, the positive electrode, and the separator thus produced were wound on the winding shaft of the winder, and the terminals separated up and down from the negative electrode and the positive electrode were thermally fused at 130 ° C. using a polypropylene polymer. The electrode assembly thus prepared was immersed in an electrolyte solution (1M LiPF ₆ in EC / DEC (50:50 v%), wound on a prepared 40 μm aluminum foil, and the ends were bonded to prepare a cylinder using aluminum foil. Polypropylene was used as the terminal and the binder polymer, and the aluminum foil was heat-sealed at 180 ° C. and bent in two stages to fabricate an AAA (10.5 X 44.5) sized battery. The discharge test was carried out as a 0.2C current, the results are as shown in Figure 8 and the capacity was 515 mAh, which showed a high energy density of 545 Wh / l, 210 Wh / kg.

As described above, the battery made by using the aluminum foil according to the present invention as an independent battery appearance, or on the inner surface of the appearance of the other material is a conventional case that used a metal can and pouch as a case in the manufacturing process By using the aluminum foil of the method of the present invention, the production is simplified and the battery can be provided with excellent energy density, stability and economic efficiency, and also it is possible to manufacture the battery in various forms, which was impossible with the conventional method. Has

Claims (3)

An electrode assembly manufacturing step of forming an electrode layer including a cathode, an anode, and a separator positioned between the cathode and the anode; An electrolyte injection step of injecting an electrolyte solution into the electrode assembly; Sealing step of sealing the electrode assembly in which the electrolyte is injected; the sealing step is to wrap the electrode assembly with aluminum foil to accommodate the inside, and after binding the finishing portion of the aluminum foil with the binding polymer, the In heat-sealing the terminal protruding to one side or both sides of the electrode assembly, the aluminum foil, the binding polymer at the same time 100 ~ 250 ℃, When the aluminum foil is used on the inner surface of the cell appearance, the appearance is any one or more selected from polyolefin, pouch, heat shrinkable tube, polyethylene terephthalate (PET), polyimide (PI), polyvinyl chloride (PVC) Method for producing a battery using an aluminum foil, characterized in that consisting of. delete delete

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