KR20010047032A - Secondary battery - Google Patents

Abstract

PURPOSE: A secondary battery is provided, which improves the structure for easy sealing by respectively forming an embossing part on a sealing part of a case receiving a battery main body and a non-embossing part on a contacting part of a battery terminal. CONSTITUTION: The secondary battery comprises: (i) a battery main body(31) where many anode plates, separators and cathode plates are laminated; (ii) an anode terminal(34) and a cathode terminal(35) which are connected to the end part of an anode tap(32) and a cathode cap(33) drawn out from the anode plate and the cathode plate; and (iii) a case which comprises an up and down separable space part receiving the battery main body, sealing parts(37a, 38a), which are formed along the border of the space part and have an embossing treated part on one side, and a non-embossing treated anode and a cathode terminal safe arriving part(310, 320).

Description

Secondary battery

The present invention relates to a secondary battery, and more particularly, to a secondary battery having an improved structure of a case accommodating the battery so that the external terminal of the battery is easily sealed when exposed to the outside of the case.

Secondary batteries, unlike primary batteries, which are not rechargeable, are rechargeable batteries, and are widely used in high-tech electronic devices such as cell phones, notebook computers, and camcorders. In particular, the lithium secondary battery has an operating voltage of 3.6 V, which is three times that of a nickel-cadnium battery or a nickel-hydrogen battery, and is rapidly increasing in view of high energy density per unit weight.

The lithium secondary battery may be classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte. Generally, a battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. do. Among them, the lithium polymer battery has flexibility and can be said to be advantageous for slimming and weight reduction of portable electronic devices in view of its relatively free shape and light weight.

As shown in FIG. 1, a conventional lithium polymer battery 10 includes a plurality of assembled batteries including a positive electrode plate 11a, a negative electrode plate 11b, and a separator 11a interposed therebetween. The laminated battery body 11, the plurality of positive electrode tabs 12 drawn from one edge of the positive electrode plate 11a and the negative electrode plate 11b, the negative electrode tab 13, and the positive and negative electrode tabs 12 ( 13) and a positive terminal 14 and a negative terminal 15, respectively, welded.

In addition, an upper case 17 for accommodating the battery body 11 and a lower portion having a space 18b formed integrally with each other at one edge of the upper case 17 and accommodating the battery body 11 are accommodated. A case 18 is provided. The upper case 17 and the lower case 18 are formed with an upper seal 17a and a lower seal 17b from edges of the space portion 18b, respectively.

Here, when assembling the battery 10, the upper case 17 and the lower case in a state in which the positive terminal 14 and the negative terminal 15 are exposed to the outside by contacting the lower sealing part 17b. When the 18 is brought into close contact with each other and a predetermined heat and pressure are applied, the upper seal 17a and the lower seal 17b are sealable.

Various methods may be provided to seal the upper case 17 and the lower case 18 to each other. A layer of a heat adhesive material may be applied to the upper seal 17a and the lower seal 17b, or The adhesive material may be adhered to the sealing portion of the jig for sealing the upper and lower cases 17 and 18 to be thermocompressed.

However, as shown in FIG. 2, the conventional battery 10 has the following problems in portions where the positive and negative terminals 14 and 15 are exposed to the outside in the upper and lower cases 17 and 18. There is this.

That is, when the upper and lower cases 17 and 18 are sealed, the positive and negative terminals 14 are exposed at portions where the positive and negative terminals 14 and 15 are exposed from the upper and lower cases 17 and 18. Due to the thickness of) 15, a step and a step are inevitably generated with the portions 21 where the terminals 14 and 15 are not formed.

Therefore, a portion where the terminals 14 and 15 are formed requires stronger heat fusion than other portions, and such excessive heat fusion is caused by the polymer material constituting the outermost layer of the upper and lower cases 17 and 18. Partial melting results in an electrical short circuit between the aluminum film disposed in the center of the polymer material layer and the positive and negative terminals 14 and 15. In addition, in the case of weak thermal fusion, minute holes 22 may be formed along edges where the terminals 14 and 15 are exposed to the outside of the upper and lower cases 17 and 18 to leak the electrolyte.

In order to prevent this, in the past, as described above, a heat-adhesive synthetic resin was attached to a molded jig for sealing, and thermal compression was performed in this case. It is not easy to adjust the pressure accurately. In the case of sealing by forming an embossed portion on the molding jig, there is a problem that the uneven shape of the upper jig and the lower jig does not completely match during compression.

The present invention was devised to solve the above problems, and the structure is improved to facilitate sealing by forming an embossed portion and a non-embossed portion at a portion where the terminals of the battery are in contact with a sealing portion of the case accommodating the battery body. The purpose is to provide a secondary battery.

1 is an exploded perspective view illustrating a conventional lithium secondary battery;

FIG. 2 is a front view of the battery of FIG. 1 in a sealed state; FIG.

Figure 3 is an exploded perspective view showing a lithium secondary battery according to an embodiment of the present invention,

4 is a front view of the battery of FIG. 3 in a sealed state;

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

10,30 battery ... 11,31 battery body

12,32 ... anode tab 13,33 ... anode tab

14,34 ... anode terminals 15,35 ... anode terminals

17,37 ... top case 17a, 37a ... top seal

18.38..Lower case 18a, 38a ... Lower seal

22 ... via 300 ... seat

310.Positive terminal seat 320 ... Positive terminal seat

In order to achieve the above object, a secondary battery according to an aspect of the present invention,

A battery body laminated in plural in order of a positive plate, a separator, and a negative plate;

A positive electrode terminal and a negative electrode terminal coupled to ends of a plurality of positive electrode tabs and negative electrode tabs drawn from the positive electrode plate and the negative electrode plate; And

The battery body is separated up and down with a space for accommodating the body, and a sealing portion is formed along the edge of the space portion, the sealing portion of any one of the sealing portion embossed portion, the positive and negative terminals are seated It is characterized in that it comprises a portion; the case is formed a positive and negative terminal seating portion that is not embossed portion.

Further, the embossed portion and the positive and negative terminal seating portions are formed with a predetermined step, and the height of the step is characterized in that it is the same as the thickness of the positive and negative terminal seated on the terminal seating portion.

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

3 illustrates a battery 30 according to an embodiment of the present invention.

Referring to the drawings, the battery 30 includes a plurality of cell tanks including a positive electrode plate 31a, a negative electrode plate 31b, and a separator 31c interposed between the positive electrode plate 31a and the negative electrode plate 31b to mutually insulate them. A long stacked battery body 31 is provided. From one edge of the positive electrode plate 31a and the negative electrode plate 31b, the positive electrode tab 32 and the negative electrode tab 33 are drawn out for each of the positive electrode plates 31a and 31b. The positive and negative electrode tabs 32 and 33 are bent in a V shape and their ends are welded to the positive electrode terminal 34 and the negative electrode terminal 35.

In addition, a case is provided to accommodate the battery body 31. That is, the case is preferably an upper case 37 and a space portion formed integrally with each other along one edge of the upper case 37 to be joined to each other to separate three surfaces, and in which the battery body 31 is accommodated. 38b), the lower case 38 is provided.

Here, the upper case 37 is formed with an upper seal portion 37a having a predetermined width and forming a closed loop along an edge of a corresponding point of the space portion 38b of the lower case 38.

In addition, the lower case 38 is formed in the lower case 38 along an edge of the space 38b which is a portion facing the upper seal 37a. At this time, when the battery 30 is assembled, the upper and lower seals are partially exposed to the outside of the positive and negative terminals 34 and 35 to the portions where the upper and lower seals 37a and 38a are joined. The part 38a is sealed by applying predetermined heat and pressure.

According to a feature of the present invention, the lower sealing portion 38a is embossed with the sealing portion 38a except for a portion corresponding to a portion where the positive and negative terminals 34 and 35 are in contact with each other. At the point where the terminals 34 and 35 contact the lower sealing portion 38a, the terminal seating portion 300 including the positive terminal seating portion 310 and the negative terminal seating portion 320, which are not embossed, is disposed. ).

More specifically, as shown in FIG. 4, the lower case 38 has a lower seal except for a point where the positive terminal 34 and the negative terminal 35 are seated in the lower seal 38b. At 38b, an embossing process in which a closed loop is formed is performed. The embossing is not performed at the point where the positive and negative terminals 34 and 35 are seated.

Accordingly, the positive and negative terminal seating portions 310 and 320 have a predetermined step with the embossed lower sealing part 38b, and the height of the step is the positive and negative terminal 34 and 35. When placed on the terminal seating portions 310 and 320, it is preferable that the upper surface thereof is formed to be able to form a horizontal plane.

Briefly looking at the manufacturing process of the lithium polymer battery 30 having such a structure, a battery body manufactured by stacking a plurality of sheets in the order of the positive electrode plate 31a, the separator 31c, the negative electrode plate 31b is provided. Subsequently, the positive electrode tab 32 and the negative electrode tab 33 drawn out from the positive electrode plate 31a and the negative electrode plate 31b are formed in a bent form with a V-shape, and the ends thereof are positive terminal 34 and negative electrode terminal 35. Weld on

On the other hand, integral upper and lower cases 37 and 38 are provided to accommodate the battery body. The lower case 38 has a lower seal 38b formed along an edge of the space 38b in which the battery body is accommodated. The positive and negative terminals 34 and 35 are formed at the lower seal 38b. Except for the part where) is seated, it is embossed.

As a result, a portion that is not embossed is formed with a step that is embossed, and a positive terminal seat 310 and a negative terminal seat on which the terminals 34 and 35 are seated in the stepped portion. 320 is formed. In addition, an upper sealing part 37a may be formed at a portion of the upper case 37 that faces the lower sealing part 38b. In this case, the upper and lower sealing parts 37a and 37b may attach separate heat adhesive material layers, and the outermost layers of the upper and lower cases 37 and 38 may have such physical properties.

Subsequently, the battery main body 31 is accommodated in the space portion 38b formed in the lower case 38. In this case, a small amount of electrolyte may be injected into the space 38b.

In addition, when the battery main body 31 is mounted in the space 38b, the positive and negative terminals 34 and 35 are simultaneously provided with the positive and negative terminal seating portions 310 provided in the lower case 38. It is seated at 320. As described above, when the terminals 34 and 35 are seated, the upper surface of the terminal 34 and 35 forms a horizontal surface with the upper surface of the lower sealing portion 38a which has been embossed.

Next, a predetermined heat and pressure are applied to the upper and lower sealing parts 37a and 38b to heat seal each other to complete the battery 30.

As described above, the secondary battery according to the present invention is embossed at a portion sealed in a case in which the battery body is accommodated, and embossing is not performed at a portion corresponding to a portion in which the positive and negative terminals are exposed to the outside of the case. By forming the positive and negative terminal seating portion may be the following effects.

Since there is no step between the positive and negative terminals and the embossed sealing part seated on the positive and negative terminal seating parts, it is possible to uniformly seal during sealing to prevent phenomena such as leakage of electrolyte solution. After assembling, the shape of the embossed part can be visually checked to improve the assemblability. In addition, since the sealing can be performed without excessive thermal fusion, it is possible to prevent an electrical short between the aluminum film included in the multilayer case and the positive and negative terminals.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (2)

A battery body laminated in plural in order of a positive plate, a separator, and a negative plate; A positive electrode terminal and a negative electrode terminal coupled to ends of a plurality of positive electrode tabs and negative electrode tabs drawn from the positive electrode plate and the negative electrode plate; And The battery body is separated up and down with a space for accommodating the body, and a sealing portion is formed along the edge of the space portion, the sealing portion of any one of the sealing portion embossed portion, the positive and negative terminals are seated And a case having a positive electrode and a negative electrode terminal seating portion, which is a portion which is not embossed. The method of claim 1, And a predetermined step is formed in the embossed portion and the positive and negative terminal seat portions, and the height of the step is the same as the thickness of the positive and negative terminal seated on the terminal seat portion.