KR20020078364A - Sealing structure and manufacturing method of secondary batteries - Google Patents

Abstract

PURPOSE: A sealing structure of a secondary battery and its preparation method are provided, to reduce the damage of the upper part of a case due to the external impact and to minimize the loss of the sealing space of a case, thereby increasing the capacity of a battery. CONSTITUTION: The sealing structure comprises a case(10) which has an open terminal(11) whose upper part is open and a receiving groove containing a receiving space; an electrode assembly which comprises a positive electrode, a negative electrode and a separator between the positive electrode and negative electrode and is received into the receiving groove of the case; an electrolyte solution which is injected into the case to allow the positive electrode and the negative electrode to be conductive; and a curable resin(40) which is charged into the open terminal to seal the case. Preferably the case is made of an aluminum material or a plastic material. The groove is formed along the circumference of the open terminal to improve the sealing efficiency of the curing resin.

Description

Sealing structure and manufacturing method of secondary batteries {Sealing structure and manufacturing method of secondary batteries}

The present invention relates to a sealing structure and a manufacturing method of a secondary battery, and more particularly to a sealing structure and a manufacturing method of a secondary battery having a structure in which the upper surface of the case containing the electrode assembly is sealed with a curable resin.

In general, as the light weight and high functionality of a portable wireless device including a video camera, a portable telephone, a portable PC, and the like progress rapidly, many studies have been conducted on batteries used as a driving power source for the wireless device. Such a battery can be charged and discharged and can be used continuously. For example, a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, a lithium secondary battery, and the like can be used. Among them, lithium secondary battery has the advantage of long life and large capacity.

The lithium secondary battery may be classified into a lithium metal battery using a liquid electrolyte, a lithium ion battery, and a lithium polymer battery using a polymer solid electrolyte according to the type of electrolyte. The lithium polymer battery may be classified into a fully solid lithium polymer battery containing no organic electrolyte at all and a lithium ion polymer battery using a gel polymer electrolyte containing an organic electrolyte, depending on the type of the polymer solid electrolyte.

A secondary battery according to the related art includes an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator, and a case surrounding and sealing the electrode assembly. Then, the electrode tab serving as an electrical passage between the electrode assembly and the outside is exposed to a predetermined length out of the case. In addition, the case is made of a polymer or aluminum material that is easy to process, the upper surface is open and has an accommodating part into which the electrode assembly is inserted, and a lid part sealing the upper surface of the open accommodating part. Therefore, in order to manufacture the conventional secondary battery, the electrode assembly is accommodated in the housing of the case, and then the electrolyte is injected and the lid is sealed. As the sealing method of the cover part, when the case shape is cylindrical, it is sealed by a beading or crimping method, and in the case of a rectangular shape, the accommodating part and the cover part are thermally fused or ultrasonically fused.

By the way, since the sealing structure of the rechargeable battery according to the related art is fusion-sealed to the upper end of the case as an example, as the fine separation space is generated between the upper end of the case and the cover part, the cover part is easily affected by external impact. There is a high risk of damage to the electrode assembly is deformed, there is a problem that the loss of the sealing space of the case occurs to reduce the battery capacity and energy density per unit volume. In addition, the economic burden is increased, such as to employ a separate manufacturing equipment for sealing the top of the case and the cover, there is a problem that the electrolyte is leaked to the outside due to incomplete sealing.

The present invention was created to improve the above problems, and improves the sealing property to minimize the loss of sealing space to increase the battery capacity and energy density per unit volume, and to produce a battery in a low cost and simple process It is an object of the present invention to provide a sealing structure and a manufacturing method of a secondary battery having a structure in which an upper surface of a case containing an assembly is sealed with a curable resin.

1 is a perspective view showing a sealing structure of a secondary battery according to an embodiment of the present invention.

2 is a cross-sectional view of FIG.

3 is a perspective view showing the electrode assembly shown in FIG.

4 is a perspective view for explaining a method of manufacturing the electrode assembly of FIG.

5 is a flow chart illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

6 is a perspective view showing a state in which the electrode assembly shown in Figure 3 is accommodated in the receiving groove of the case.

7 is a perspective view showing another embodiment of the case shown in FIG.

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

10,50 ... case 11,51 ... open end

12 ... receiving groove 20 ... electrode assembly

21 ... Separator 22 ... Positive terminal

23.positive plate 24 ... cathode terminal

25 ... cathode plate 30 ... electrolyte

40 ... hardening resin 52 ... uneven groove

The present invention for achieving the above object, the case having an open end with an open upper surface, and a receiving groove provided with a storage space of a predetermined volume; An electrode assembly having a positive electrode plate, a negative electrode plate, and a separator for isolating the positive electrode plate and the negative electrode plate, respectively, and received in a receiving groove of the case; An electrolyte solution injected into the case so that the positive electrode plate and the negative electrode plate have conductivity; And a curable resin filled in the open end to seal the case.

The case is preferably made of an aluminum material or a plastic material, it is preferable that the uneven groove is formed along the edge of the open end in order to improve the sealability of the curable resin.

It is preferable that a polyimide or polyethylene acrylic acid copolymer is coated on the inner edge of the open end to facilitate binding of the open end edge and the curable resin of the case, and the curable resin is preferably made of epoxy resin or acrylic resin. Do.

In addition, the present invention for achieving the above object, the positive electrode plate and the negative electrode plate each of the steps of forming an electrode assembly of a structure separated by a separator; Accommodating the electrode assembly in a receiving groove of an open top case and injecting an electrolyte solution; And filling and sealing the curable resin in the open end of the case.

Before filling the curable resin in the open end of the case, it is preferable to apply a polyimide or polyethylene acrylic acid copolymer to the inner edge of the open end, the curable resin preferably comprises an epoxy resin or acrylic resin. .

Accordingly, the present invention has a structure that can minimize the loss of the sealing space of the case by filling the curable resin in the open end of the case in which the electrode assembly is accommodated, unlike the prior art, the upper surface of the case is easily deformed by external impact There is no risk of damage to the electrode assembly, and the loss of the sealing space of the case is minimized, thereby increasing the capacity of the battery and increasing the energy density per unit volume, and manufacturing a separate to seal the upper surface and the lid of the case as in the prior art. Not only does it need to adopt equipment, the economic burden is reduced, and the sealing of the upper surface of the case is possible, so that the electrolyte does not leak out.

Hereinafter, a sealing structure of a secondary battery according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, the sealing structure of the secondary battery according to a preferred embodiment of the present invention has an open end 11 having an open upper surface and a receiving groove 12 is provided with a predetermined volume of storage space. The case 10, the electrode assembly 20 accommodated in the receiving groove 12 of the case 10, the electrolyte 30 injected into the case 10, and the case 10 are opened to seal the case 10. Curable resin 40 to be filled in the stage (11).

Preferably, the case 10 is made of aluminum or plastic material, and has an open end 11 having an upper surface open to accommodate the electrode assembly 20, and a storage of a predetermined volume in which the electrode assembly 20 is combined. It takes a hexahedron or cylindrical shape provided with a receiving groove 12 having a space. In addition, the case 10 may be formed of polyimide or polyethylene on the inner edge of the open end 11 side where the curable resin 40 is in contact with the curable resin 40 to improve mutual binding with the material of the case 10. Acrylic acid copolymer is applied.

As shown in FIG. 3, the electrode assembly 20 has a structure in which the positive electrode plate 23 and the negative electrode plate 25 are separated from each other by the separator 21 and stacked in a plurality. As shown in FIG. 4, the electrode assembly 20 is continuously bonded to one side of the separator 21 having a predetermined width and length at equal intervals and has an anode terminal 22 serving as an electrical passage with the outside. To the negative electrode plate 25 having a positive electrode plate 23 and the negative electrode terminal 24 continuously attached to the other side of the separator 21 at positions corresponding to the positive electrode plate 23 at equal intervals and serving as an electrical passage to the outside. The positive electrode plate 23 and the negative electrode plate 25 are folded and pressed so as to alternate with each other.

The electrode assembly 20 is accommodated in the receiving groove 12 of the case 10, the positive terminal 22 of the positive electrode plate 23 and the negative terminal 24 of the negative electrode plate 25 is the opening of the case 10 The stage 11 is exposed to the outside in a state where the curable resin 40 is filled (see FIG. 2).

The electrolyte 30 is injected into the case 10 such that the positive electrode plate 23 and the negative electrode plate 25 of the electrode assembly 20 have conductivity.

As shown in FIG. 1 and FIG. 2, the curable resin 40 accommodates the electrode assembly 20 in the receiving groove 12 of the case 10 and injects the electrolyte solution 30 into the case 10. In one state, it is applied to the open end 11 of the case 10 to completely seal the upper end of the case 10, and preferably includes an epoxy resin or an acrylic resin. That is, the curable resin 40 is filled in the open end 11 of the case 10 in a liquid state and cured to a predetermined thickness to cover the top surface of the case 10 and bind to the inner edge of the open end 11.

As shown in FIG. 7, the case 50 according to another exemplary embodiment of the present invention has an edge of the open end 11 to improve the sealing property of the curable resin 40 filled in the open end 51. Along the concave and convex groove 52 formed in succession is provided. More preferably, the uneven groove 52 is bent in a wave shape along the edge of the open end 51 side of the case 50, and the curable resin 40 is filled in the open end 51 and cured. When bound to the groove area of the unevenness, it is more strongly bound to the inner edge of the open end 51.

A method of manufacturing a secondary battery according to a preferred embodiment of the present invention having the above configuration will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 4, the positive electrode plate 23 and the negative electrode plate 25 are continuously bonded to both surfaces of the separator 21 having a predetermined width and length by a predetermined interval. The separator 21 preferably includes a single or multilayer polymer porous membrane made of ordinary polyethylene or polypropylene. In addition, the positive electrode plate 23 is cut into a predetermined size by coating and drying a positive electrode active material on the metal surface of the foil (foil) such as aluminum. In addition, the negative electrode plate 25 is coated with a negative electrode active material on a metal surface of a foil state such as copper, dried and cut into a predetermined size.

Next, the separator 21 is folded a plurality of times so that the positive electrode plate 23 and the negative electrode plate 25 alternate with each other. Then, the positive electrode plate 23 and the negative electrode plate 25 are laminated while being separated by the separator 21, and when the electrode plate 20 is compressed by a conventional compressor, the electrode assembly 20 is manufactured (S1 of FIG. 5).

Subsequently, as shown in FIG. 6, the electric electrode assembly 20 is accommodated in the accommodation groove 12 of the case 10 (S2 of FIG. 5). At this time, the positive electrode terminal 22 of the plurality of laminated positive electrode plates 23 and the negative electrode terminal 24 of the negative electrode plate 25 protrudes a predetermined length upward from the open end 11 of the case 10.

Next, the positive electrode plate 23 and the electrolyte 30 are injected into the case 10 in which the electrode assembly 20 is housed so that the positive electrode plate 23 and the negative electrode plate 25 of the electrode assembly 20 have conductivity. The negative electrode plate 25 is impregnated (S3 in Fig. 5).

Subsequently, the open end 11 of the case 10 illustrated in FIG. 6 is filled with a curable resin 40 such as a liquid epoxy resin or an acrylic resin and then cured (S4 of FIG. 5). Then, as shown in FIG. 2, the open end 11 of the case 10 is completely sealed by the curable resin 40 cured to a predetermined thickness. At this time, since the positive electrode terminal 22 and the negative electrode terminal 24 of the electrode assembly 20 protrude upwardly from the open end 11 when accommodated in the receiving groove 12 of the case 10, Through the curable resin 40 side is exposed to the outside.

On the other hand, before filling the curable resin 40, it is preferable to apply a polyimide or polyethylene acrylic acid copolymer to the inner edge of the open end 11 of the case 10. That is, the polyimide or polyethylene acrylic acid copolymer coated on the inner edge of the open end 11 of the case 10 is excellent in mutual binding with the material of the case 10 and the curable resin 40 and thus the curable resin 40 To improve the sealability.

In addition, as shown in FIG. 7, as another embodiment for further improving the sealing property of the curable resin 40, the uneven groove 52 may be continuously formed at the edge of the open end 51 of the case 50. It may be. That is, since the curable resin 40 is filled and cured in a liquid state, the curable resin 40 is strongly bound to the groove region of the uneven groove 52 during curing to completely seal the upper surface of the case 50.

Therefore, the secondary battery of the present invention can minimize the loss of the sealing space of the case by the curable resin is filled in the open end of the case and cured to a certain thickness.

As described above, the sealing structure and manufacturing method of the secondary battery according to a preferred embodiment of the present invention has the following effects.

First, since it has a structure that can minimize the loss of the sealing space of the case by filling the curable resin in the open end of the case in which the electrode assembly is accommodated, the upper surface of the case is not easily deformed by external impact unlike the conventional There is no fear of damage to the assembly.

Second, as the loss of the sealing space of the case is minimized, the capacity of the battery is increased and the energy density per unit volume is increased.

Third, the economic burden is reduced because it does not need to employ a separate manufacturing equipment for sealing the top of the case and the lid as in the prior art, not only simplify the manufacturing process, it is also possible to fully seal the top of the case leakage of the electrolyte to the outside It doesn't work.

Claims (8)

A case having an open end with an open top, and a receiving groove provided with a storage space of a predetermined volume; An electrode assembly having a positive electrode plate, a negative electrode plate, and a separator for isolating the positive electrode plate and the negative electrode plate, respectively, and received in a receiving groove of the case; An electrolyte solution injected into the case so that the positive electrode plate and the negative electrode plate have conductivity; And And a curable resin filled in the open end to seal the case. The method of claim 1, The case is a sealing structure of a secondary battery, characterized in that made of aluminum or plastic material. The method of claim 1, The case is: Sealing structure of the secondary battery, characterized in that the grooves are formed along the edge of the open end to improve the sealability of the curable resin. The method of claim 1, Sealing structure of the secondary battery characterized in that the polyimide or polyethylene acrylic acid copolymer is applied to the inner edge of the open end to facilitate the binding of the open end edge and the curable resin of the case. The method of claim 1, The curable resin is a sealing structure of a secondary battery, characterized in that made of epoxy resin or acrylic resin. Forming an electrode assembly having a structure in which a positive electrode plate and a negative electrode plate are separated from each other by a separator; Accommodating the electrode assembly in a receiving groove of an open top case and injecting an electrolyte solution; And And filling and sealing the curable resin in the open end of the case. The method of claim 6, A method of manufacturing a secondary battery, characterized in that the polyimide or polyethylene acrylic acid copolymer is applied to the inner edge of the open end before filling the curable resin in the open end of the case. The method of claim 6, The curable resin is a secondary battery manufacturing method characterized in that it comprises an epoxy resin or acrylic resin.