KR101464965B1 - Manufacturing of Battery Cell by Curbed Shaped - Google Patents

Abstract

The present invention provides a method of manufacturing a battery cell having both sides bent,
(a) pressing both side surfaces of the cell case so that one side of the variable cell case has a radius of curvature (R ₁ ) and the other side has a radius of curvature (R ₂ );
(b) injecting an electrode assembly and an electrolyte into the cell case, and sealing the cell assembly to manufacture a battery cell; And
(c) transforming both sides of the battery cell into curvature radii (R ₁ ', R ₂ ') by performing charge / discharge for activation of the battery cells;
The method of manufacturing a battery cell according to the present invention includes the steps of:
Such a battery cell manufacturing method can minimize unnecessary space waste due to the close contact structure when mounted on a device having a curved outer shape or mounted on a curved surface portion inside the device, so that it has an efficient and beautiful appearance, And it is possible to develop a device having various designs according to taste.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell,

More particularly, the present invention relates to a method of manufacturing a battery cell having both side surfaces bent, wherein one side of the variable cell case has a curvature radius (R ₁ ) Pressing both side surfaces of the cell case so as to have a radius of curvature (R ₂ ); Injecting an electrode assembly and an electrolyte into the cell case, and sealing the cell assembly to manufacture a battery cell; And (c) performing charging and discharging for activation of the battery cells to deform both sides of the battery cells into curvature radii (R ₁ ', R ₂ ').

As technology development and demand for mobile devices have increased, the demand for secondary batteries as energy sources has been rapidly increasing. Many researches have been conducted on lithium secondary batteries with high energy density and discharge voltage among such secondary batteries. .

Typically, in view of the shape of the battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery that can be applied to products such as mobile phones with a small thickness. In terms of materials, lithium ion batteries having high energy density, discharge voltage, There is a high demand for a lithium secondary battery such as a lithium ion polymer battery.

In such a secondary battery, since electronic devices are becoming smaller and thinner depending on the taste of the consumer, the shape of the battery is also required to be reduced in size and thickness in order to minimize unnecessary space waste. Therefore, it is necessary to realize various shapes of the battery according to the shape of the device and efficiently utilize the inner space of the device.

In particular, in recent years, since the design of the device itself is a very important factor in the selection of the product of the consumer, various designs are being designed by avoiding the planar design considering the productivity and the like. For example, a device such as a mobile phone, a notebook, or the like can be designed with a predetermined curved surface for an ergonomic design.

As described above, many designs having a curved surface formed on the outer surface have been developed and put into practical use. However, since most of the commercialized batteries are flat, unnecessary space is wasted and it is difficult to stably install the battery There is a problem that the battery may be damaged due to external impact.

Therefore, when a curved surface is formed at a position where a battery is to be mounted in a device in which a curved surface is formed, there is an urgent need for a battery having a curved portion so as to be stably mounted on such a device.

In this connection, in some prior arts, there is a technique of forming a curved surface in an electrode assembly, but all of the above technologies have a serious problem in that deterioration of the battery is caused by performing direct compression molding on the electrode assembly itself. Furthermore, since the above-described techniques perform the process of causing warping in the state of the electrode assembly, the battery case also has a burden on the manufacturing process to be deformed as described above. Also, when the electrolyte is injected and filled with the warped electrode assembly mounted on the battery case, the stress inherent in the electrode assembly during the warping tends to be recovered by the plasticizing action of the electrolyte. As a result, There is a problem that the possibility of a short circuit is increased by being pressed by the inner surface of the battery case.

In order to solve such a problem, another prior art has already introduced a shape deformation corresponding to the device structure by pressing the state of the battery cell in which the electrode assembly is already mounted.

FIG. 1 schematically shows an exemplary manufacturing process of such a battery cell 40. FIG.

Referring to FIG. 1, a conventional battery cell 40 includes: (A) a process of attaching an electrode assembly 50 to a cell case 10 and sealing the battery cell 20 with an electrolyte injected thereinto; (B) pressing both sides of the battery cell 20 with the same force; (C) charging and discharging the battery cell (30).

However, in the above-described process (A), the electrode assembly 50 is pressed in the state of the battery cell 20 in which the electrode assembly 50 is mounted, so that the shape deformation of the electrode assembly 50 built in the battery cell 20 may be induced Thereby causing damage to the electrode assembly 50, thereby deteriorating the battery.

In addition, since both sides of the battery cell 30 are expanded and protruded when the charging and discharging are performed on the battery cell 30 whose both sides are pressed with the same force, the battery cell 40 having a convex shape is obtained. There is a problem in that it does not have the above.

Therefore, there is a high need for a manufacturing method of a secondary battery (battery cell) in which the above-mentioned problems can be solved and the both sides of the battery cell are bent so as to form a gentle curved surface.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments, and have provided a method of manufacturing a battery cell having both sides of a predetermined radius of curvature and corresponding to the shape of a device. By using the battery cells according to the manufacturing method of the battery cells, it is possible to minimize the unnecessary space waste, and it is possible to develop devices having various designs according to the taste of the consumers, and also to solve the problems of the above- And the present invention has been accomplished.

Accordingly, the present invention provides a method of manufacturing a battery cell having both sides bent,

(a) pressing both side surfaces of the cell case so that one side of the variable cell case has a radius of curvature (R ₁ ) and the other side has a radius of curvature (R ₂ );

(b) injecting an electrode assembly and an electrolyte into the cell case, and sealing the cell assembly to manufacture a battery cell; And

(c) transforming both sides of the battery cell into curvature radii (R ₁ ', R ₂ ') by performing charge / discharge for activation of the battery cells;

And a battery cell.

As described above, in the prior art in which direct deformation is applied to the electrode assembly or the electrode plate, severe deformation occurs due to shrinkage / expansion of the electrode plate in the initial charge / discharge process after the electrolyte is injected. In order to solve such a problem, there is a problem in that even in the technique of applying deformation to the battery cell having the electrode assembly, damage to the electrode assembly may be caused due to deformation of the battery cell, Both side surfaces of the battery cells expand in a convex shape during the discharge process, so that there is a problem that a battery cell having a shape corresponding to the device structure can not be manufactured.

On the other hand, according to the manufacturing method of the present invention, since the electrode assembly is mounted after inducing the shape deformation in the cell case, it is possible to solve the problem of inducing deformation in the battery cell in which the electrode assembly is mounted. Further, since both side surfaces of the cell case are bent to have different radii of curvature, both side surfaces of the battery cell can be bent in the same direction even if the battery cell expands during charging and discharging. As a result, It is possible to provide a battery cell suitable for the battery.

In the present invention, the cell case has variable characteristics so that it can be easily bent. That is, the variable cell case can be deformed by the applied external force. Since the resin outer layer has excellent resistance from the external environment, it is necessary to have a tensile strength and weather resistance of a predetermined level or higher. In this respect, polyethylene terephthalate (PET) and stretched nylon film can be preferably used as the polymer resin of the resin outer layer.

The metal barrier layer may preferably be made of aluminum so as to exhibit a function of improving the strength of the battery case, in addition to a function of preventing foreign matter such as gas or moisture from leaking or leaking.

As the polymer resin of the resin sealant layer, a polyolefin resin having a low heat absorbing property (heat adhesion property) and low hygroscopicity in order to suppress penetration of an electrolyte solution and not being swollen or eroded by an electrolytic solution is preferably used And more preferably unleaded polypropylene (CPP) can be used.

In general, a polyolefin resin such as polypropylene has a low adhesive force with a metal. Therefore, as an approach for improving the adhesion with the metal barrier layer, it is preferable to further include an adhesive layer between the metal layer and the resin sealant layer, And blocking characteristics can be improved. Examples of the material of the adhesive layer include a urethane-based material, an acryl-based material, a composition containing a thermoplastic elastomer, and the like, but are not limited thereto.

In one preferred example, the battery cell manufactured according to the manufacturing method of the present invention may have a structure in which the electrode assembly of the anode / separator / cathode laminate structure is embedded in a cell case having a curved surface formed on both sides thereof with the electrolyte impregnated therein .

Therefore, in the case of a device having an external shape formed with a curved surface having a specific shape as described above, or a device in which the outer surface is a flat surface, but the shape of the mounting portion of the battery cell is a curved surface of a specific shape, , It is possible to minimize unnecessary space waste by having a close contact structure at the mounting site, and it is possible to develop a device having various designs according to consumer's taste.

As the electrode assembly in the present invention, for example, a wound electrode assembly or a stacked electrode assembly may be used. In one preferred embodiment, the electrode assembly may be a stack / folding type electrode assembly in which a stacked bi-cell or pull cell is sequentially wound as a unit cell by a long separator sheet. Details of the electrode assembly of the stack / folding type structure are disclosed in Korean Patent Application Laid-Open Nos. 2001-0082058, 2001-0082059 and 2001-0082060, the contents of which are incorporated herein by reference Are incorporated into the present invention.

In another preferred embodiment, the electrode assembly may be a stacked electrode assembly in which two or more positive electrodes and two or more negative electrodes are sequentially stacked with a separator interposed therebetween.

In the process (a), the radius of curvature R ₁ may be smaller than the radius of curvature R ₂ . As described above, in the method for manufacturing a battery cell according to the present invention, since both side surfaces of the cell case are pressed to have different radii of curvature (R ₁ , R ₂ ), the both sides are asymmetrically bent A cell case is manufactured.

In one preferred example, the radius of curvature R ₁ of one side is in the range of 5 to 100 cm and the radius of curvature R ₂ of the other side is in the range of infinity to greater than the radius of curvature R ₁ . Particularly preferably, the other side is not curved and the radius of curvature R ₂ may be infinite. The radius of curvature R ₁ and the radius of curvature R ₂ can be variously adjusted according to a desired shape. However, if the radius of curvature R ₁ and the radius of curvature R ₂ are too small, It is difficult to mount the electrode assembly in the process (b), and if the radius of curvature (R ₁ ) is too large, the battery cell may excessively expand in the process (c) It is not preferable.

In the above process (a), the pressing is performed at room temperature, so that the deformation can be induced without heating as in the conventional method, so that the manufacturing process is easy.

In one preferred embodiment, step (a) may include pressing both sides of the cell case to different sizes, and more preferably, the inner surface may have a different curvature radius (R ₁ , R ₂ ) And inserting the cell case between the members and pressurizing the cell case.

The battery case having different curvature radii R ₁ and R ₂ on both sides in the process (a) forms a curvature radius R ₁ ', R ₂ ' by bending the both sides in the same direction gently in the process (c) can do.

Specifically, in the charging and discharging process of the process (c), one side having a small radius of curvature (R ₁ ) is deformed relative to the other side having a curvature radius (R ₂ ) under the same conditions, small, and therefore bent in the same two opposite side direction with respect to the center in the vertical section in the axial direction, the deformation in the radius of curvature (R ₁₎ is a curvature radius (R ₁ ') in a range larger than the radius of curvature (R ₁₎ of the battery cells and, the radius of curvature of the battery cell (R ₂₎ may be modified to a radius of curvature (R ₂ ') in a range between the radius of curvature (R _2). The difference between the curvature radius R ₁ 'and the curvature radius R ₂ ' may be, for example, 50% or less based on the magnitude of the radius of curvature R ₁ ' R ₁ ') and the curvature radius R ₂ ' may be the same.

The present invention also provides a battery pack, characterized in that it is built in a battery cell manufactured by the above method and a pack case bent in the same shape as the battery cell.

Such a battery pack can be used as a power source for various devices, for example, a mobile phone, a smart pad, a notebook computer, a netbook, a tablet PC, and the like.

More details on this will be described later in the drawings and the like.

As described above, in the method for manufacturing a battery cell according to the present invention, since a cell is manufactured by introducing an electrode assembly or the like into such a cell case after pressurizing the cell case to induce shape deformation, The problem of the method of inducing can be solved. In addition, since both side surfaces of the cell case have different radiuses of curvature in the shape deforming process, a battery cell corresponding to the shape of the device can be provided in charge and discharge processes.

1 is a schematic view of a process of manufacturing a battery cell according to a conventional method;
2 is a schematic view illustrating a process of manufacturing a battery cell according to an embodiment of the present invention;
3 is a perspective view of a battery pack including a curved battery cell according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited thereto.

FIG. 2 schematically shows a manufacturing process of a battery cell 400 having different curvature radii R ₁ 'and R ₂ ' on both sides according to an embodiment of the present invention.

Referring to FIG. 2, in the process (a), the upright-shaped cell case 100 is formed so that the side surface (left side) has a radius of curvature R ₁ and the other side (right side) has a radius of curvature R ₂ . Is pressed. The radius of curvature R ₁ may be determined in a range of 5 to 100 cm and the radius of curvature R ₂ may be determined in a range from a condition larger than a curvature radius R ₁ to infinity. Such a pressing process may be performed by applying pressure of different magnitudes to both sides of the cell case 100. However, in some cases, the pressing process may be performed between pressing members (not shown) having different radiuses of curvature R ₁ and R ₂ And the cell case 100 may be inserted.

In step (b), the electrode assembly 500 and the electrolyte solution are injected into the cell case 200 of the aluminum laminate sheet, and then the battery cell 300 is manufactured by sealing. Although the cell case 200 has curved radii R ₁ and R _{2 on} both sides thereof, the diameter of the central portion on the vertical cross section in the axial direction is large enough to allow the electrode assembly 500 to be inserted. Unlike the conventional manufacturing process of FIG. 1, since the electrode assembly 500 is mounted in a state where the cell case 200 is already deformed, there is no fear that the shape of the electrode assembly 500 is deformed during the pressing process .

In step (c), charge / discharge for activation is performed to fabricate a battery cell 400 having curved radii R ₁ 'and R ₂ ' on both sides. In such a battery cell 400, for example, the radius of curvature (R ₁₎ of the battery cell 200 is deformed in the radius of curvature (R ₁ ') in a range larger than the radius of curvature (R _1), cells ( 200 radius of curvature (R ₂₎ of a) is modified with a radius of curvature (R ₂ ') in a range between the radius of curvature (R _2). The radius of curvature R ₁ 'and the radius of curvature R ₂ ' may have various sizes depending on charge / discharge conditions, but the difference between the curvature radius R ₁ 'and the curvature radius R ₂ ' Is determined in a range of not more than 50% based on the size of the film (R ₁ ').

As described above, one side having a small radius of curvature (R ₁ ) has a relatively small deformation force due to the expansion of the battery as compared with the other side having a relatively large radius of curvature (R ₂ ) under the same conditions. Therefore, when charging / discharging is performed on the battery cell 300 having the curved radii R ₁ and R ₂ of which sides are different from each other, the curvature radius R ₁ ' , R ₂ ') of the battery cell can be made substantially the same.

3 illustrates a battery pack including a curved battery cell according to an embodiment of the present invention.

3, the pack case of the battery pack 600 includes a pack case body 610 having the same shape as the battery cell and having curved surfaces on both sides of the outer surface, an upper cap 620 mounted on the upper surface thereof, And a lower end cap (not shown) mounted on the lower end surface thereof. The upper cap 620 is formed with a groove portion 621 so that the external input / output terminal can be protruded.

The battery pack 600 having a predetermined curved surface is mounted on a device having a design with various curved surfaces such as a cellular phone, so that the inner space can be efficiently used, and a device with a close contact structure can be manufactured. Accordingly, it is possible to develop a device having various designs according to the taste of a consumer, and ultimately contribute to diversification of products.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (14)

A method of manufacturing a battery cell having both side surfaces bent,
(a) pressing both side surfaces of the cell case so that one side of the variable cell case has a radius of curvature (R ₁ ) and the other side has a radius of curvature (R ₂ );
(b) injecting an electrode assembly and an electrolyte into the cell case, and sealing the cell assembly to manufacture a battery cell; And
(c) transforming both sides of the battery cell into curvature radii (R ₁ ', R ₂ ') by performing charge / discharge for activation of the battery cells;
Wherein the battery cell comprises a plurality of battery cells. The electrode assembly according to claim 1, wherein the electrode assembly is a stacked / folded electrode assembly in which stacked bipolar cells or pull cells are sequentially wound by a separator sheet as a wound electrode assembly, a stacked electrode assembly, or a unit cell Wherein the battery cell is a battery cell. The method of claim 1, wherein the radius of curvature (R ₁ ) in the process (a) is smaller than the radius of curvature (R ₂ ). The battery according to claim 3, wherein the radius of curvature (R ₁ ) is in a range of 5 to 100 cm, and the radius of curvature (R ₂ ) is in a range from a condition larger than a curvature radius (R ₁ ) ≪ / RTI > The method for manufacturing a battery cell according to claim 1, wherein the other side is not bent and the radius of curvature (R ₂ ) is infinite. The method of claim 1, wherein the pressing in step (a) is performed at room temperature. The method as claimed in claim 1, wherein the step (a) includes the step of inserting the cell case between the pressing members having different radii of curvature (R ₁ , R ₂ ) Gt; The method of claim 1, wherein the radius of curvature (R ₁₎ of the battery cell in the step (c) is transformed into a radius of curvature (R ₁ ') in a range larger than the radius of curvature (R _1), the radius of curvature of the battery cell ( R ₂₎ the method of manufacturing the battery cell characterized in that the variations in the radius of curvature (R ₂ ') in a range between the radius of curvature (R _2). The battery cell manufacturing method according to claim 1, wherein the difference between the curvature radius (R ₁ ') and the curvature radius (R ₂ ') is in a range of 50% or less based on the radius of curvature radius (R ₁ ' Way. The method of claim 1, wherein the radius of curvature (R ₁ ') and the radius of curvature (R _2') is a battery cell manufacturing method according to claim same. delete delete delete delete

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