Electrode assembly and secondary battery including the same

An electrode assembly and a secondary battery including the same. The electrode assembly includes a plurality of alternately disposed positive electrode plates and negative electrode plates, separators disposed between the positive electrode plates and the negative electrode plates, a plurality of positive electrode tabs formed in the plurality of positive electrode plates, a plurality of negative electrode tabs formed in the plurality of negative electrode plates, a positive electrode lead including a clip accommodating the plurality of positive electrode tabs and a lead line coupled to the clip, and a negative electrode lead including a clip accommodating the plurality of negative electrode tabs and a lead line coupled to the clip.

CLAIM OF PRIORITY

This application makes reference to, incorporates into this specification the entire contents of, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on Dec. 1, 2009, and there duly assigned Serial No. 10-2009-0117882.

BACKGROUND OF THE INVENTION

Field of the Invention

An embodiment of the present invention relates to an electrode assembly and a secondary battery including the same, and more particularly, to an electrode assembly generating a large capacity of current and a secondary battery including the same.

Description of the Related Art

As the use of portable electronic apparatus increases, the use of a rechargeable secondary battery is increasing. In accordance with the request of a user, researches on making a secondary battery small and light are being performed.

Since a lithium (Li) battery as a representative secondary battery has higher operation voltage and energy density per unit weight than a nickel-cadmium (Ni—Cd) battery or a nickel-hydrogen (NI-MH) battery, the use of the Li battery is increasing.

The lithium battery is divided into a lithium-ion battery for which liquid electrolyte is used and a lithium-polymer battery for which high molecular electrolyte is used. The lithium battery may have various shapes such as a cylinder type, a prismatic type, and a pouched type in accordance with the shape of a case.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to provide an improved electrode assembly and an improved secondary battery.

In addition, the present invention has been made to provide an improved electrode assembly in which a large capacity of electrons easily move and a secondary battery including the same.

In order to achieve the foregoing and/or other aspects of the present invention, according to an aspect of the present invention, there is provided an electrode assembly, including a plurality of alternately disposed positive electrode plates and negative electrode plates, separators provided between the positive electrode plates and the negative electrode plates, a plurality of positive electrode tabs formed in the plurality of positive electrode plates, a plurality of negative electrode tabs formed in the plurality of negative electrode plates, a positive electrode lead including a clip accommodating the plurality of positive electrode tabs and a lead line coupled to the clip, and a negative electrode lead including a clip accommodating the plurality of negative electrode tabs and a lead line coupled to the clip.

According to another aspect of the present invention, there is provided a secondary battery, including the electrode assembly and a case including a main body accommodating the electrode assembly and a cover that contacts the main body in order to seal up the electrode assembly in the state where parts of the lead lines are exposed to the outside.

In the electrode assembly according to the present invention, the plurality of electrode tabs are accommodated in the clips of the electrode leads. A plurality of pins formed in the clips are inserted into holes formed in the plurality of electrode tabs. Alternatively, a plurality of protrusions formed in the clips compress the plurality of electrode tabs. As a result, the electrode tabs may be stably coupled to the electrode leads, a contact area between the plurality of electrode tabs and the electrode leads may increase, and a large capacity of current may easily move. Therefore, a high output secondary battery stably outputting the large capacity of current may be realized.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided so that those skilled in the art may fully understand the present invention and may have various modifications. The scope of the present invention is not limited to the embodiments described hereinafter.

The secondary battery includes an electrode assembly generating current and a case sealing up and protecting the electrode assembly. The electrode assembly includes positive electrode plates and negative electrode plates including electrode tabs, separators interposed between the positive electrode plates and the negative electrode plates, and electrode leads coupling the electrode tabs to an external circuit.

In general, the current generated by the electrode assembly is output to an external circuit through the electrode tabs and the electrode leads. When the amount of the output current increases as the capacity of the secondary battery increases, however, the current channel provided by the electrode tabs and the electrode leads is insufficient, and it is difficult to stably couple the plurality of electrode tabs to electrode leads so that a large capacity of electrons do not easily move.

FIG. 1is an oblique view illustrating an electrode assembly constructed as an embodiment according to the principles of the present invention.FIG. 2is a cross-sectional view of the electrode assembly taken along line I1-I2ofFIG. 1.

Referring toFIGS. 1 and 2, an electrode assembly100according to the present invention includes positive electrode plates10where positive electrode tabs12are formed, negative electrode plates20where negative electrode tabs22are formed, separators30provided between positive electrode plates10and negative electrode plates20, a positive electrode lead40coupled to positive electrode tabs12, and a negative electrode lead50coupled to negative electrode tabs22.

The plurality of positive electrode plates10and negative electrode plates20are alternately disposed and separators30are provided between positive electrode plates10and negative electrode plates20. That is, positive electrode plates10, separators30, and negative electrode plates20are sequentially laminated.

Positive electrode plates10are made of an aluminum (Al) thin film. Negative electrode plates20may be made of a copper (Cu) thin film. Positive electrode plates10and negative electrode plates20are coated with an active material. For example, positive electrode plates10are coated with a positive electrode active material obtained by mixing a lithium based oxide, a binder, and a conductive material with each other; and negative electrode plates20are coated with the a negative electrode active material obtained by mixing a material containing carbon, a binder, and a conductive material with each other.

Separators30are made of an insulating layer having high ion transmittance and mechanical strength, for example, sheet or non-woven fabric made of olefin based polymer such as chemistry resistant and hydrophobic polypropylene, glass fiber, or polyethylene. Separators30may be formed to be larger than positive electrode plate10and negative electrode plate20for electric insulation.

Positive electrode tab12and negative electrode tab22are extended from one surface of respectively corresponding one of positive electrode plate10and negative electrode plate20and are formed on the other side not to contact each other. Positive electrode tab12may be made of aluminum (Al), and negative electrode tab22may be made of nickel (Ni).

Positive electrode lead40and negative electrode lead50include clips42and52respectively accommodating the plurality of positive electrode tabs12and negative electrode tabs22that are respectively aligned in a line, and lead lines44and54respectively coupled to clips42and52. After the plurality of positive electrode tabs12and negative electrode tabs22are respectively aligned in a line, the plurality of positive electrode tabs12and the negative electrode tabs may be bent to be easily coupled to clips42and52, respectively. For example, positive electrode tabs12and negative electrode tabs22that are aligned in a line are respectively inserted into clips42and52, and then are compressed so that positive electrode tabs12are coupled to positive electrode lead40and that negative electrode tabs22are coupled to negative electrode lead50.

FIG. 3is a cross-sectional view illustrating an electrode assembly constructed as the first embodiment according to the principles of the present invention. Holes12aand22aare formed in positive tabs12and negative electrode tabs22that are respectively aligned in a line. Pins42aand52aare respectively formed on one side of clips42and52, to be inserted into holes12aand22a, respectively, and to be inserted into an opposite side of clips42and52, respectively. Grooves43and53accommodating pins42aand52amay be formed on the opposite sides of clips42and52corresponding to pins42aand52a, respectively. When the vertical ends of pins42aand52arespectively contact the bottom surfaces of grooves24band52b, positive electrode tabs12and negative electrode tabs12may move or conflict. Therefore, the bottom surfaces of pins42aand52amay be respectively separated from the bottom surfaces of grooves24band52bby a uniform distance.

FIG. 4is a cross-sectional view of an electrode assembly constructed as the second embodiment according to the principles of the present invention. At least one holes12aand22aare respectively formed in positive electrode tabs12and negative electrode tabs22that are respectively aligned in a line. Pins42band52bare respectively formed on both sides of clips42and52that respectively contact positive electrode tabs12and negative electrode tabs22. Pins42band52bare inserted into holes12aand22a, respectively. When both ends of upper and lower pins42band52bcontact, friction may be generated. Therefore, upper pins42band52bmay be separated from lower pins42band52bby a predetermined distance. That is, the pins42band52bthat are respectively formed on one side of clips42and52, may be separated from the pins42band52bthat are respectively formed on an opposite side of clips42and52.

In the electrode assembly constructed as the first and second embodiments according to the principles of the present invention, positive electrode tabs12and negative electrode tabs22may be made of Fe and the surfaces of positive electrode tabs12and negative electrode tabs22may be plated with Ni. In addition, holes12aand22amay be cylindrical. However, front and rear side margins of the holes may expand, and left and right side margins of the holes may be minimized, so that the holes may be formed to have an elliptical shape.

FIG. 5is a cross-sectional view of an electrode assembly constructed as the third embodiment according to the principles of the present invention. Protrusions42cand52care respectively formed on both sides of clips42and52that contact positive electrode tabs12and negative electrode tabs22.

Since the degree of the compression between positive electrode tabs12and the compression between negative electrode tabs22increases due to protrusions42cand52crespectively formed on both sides of clips42and52, positive electrode tabs12may be stably coupled to positive electrode lead40and negative electrode tabs22may be stably coupled to negative electrode lead50.

FIG. 6Ais a cross-sectional view of an electrode assembly constructed as the fourth embodiment according to the principles of the present invention. A plurality of triangular (saw tooth-shaped) symmetrically oriented protrusions42dand52dare formed on both sides of clips42and52that provide laterally opposite serrated arrays which contact positive electrode tabs12and negative electrode tabs22, respectively. In order to be effectively compressed, positive electrode tabs12and negative electrode tabs22are made of a flexible metal such as Al, and a plurality of protrusions42dand52dare provided on both sides of clips42and52. The plurality of protrusions42dand52dprovided on a first side of clips42and52are formed to cross the plurality of protrusions42dand52dprovided on a second and opposite side of clips42and52. Since positive electrode tabs12and negative electrode tabs22are compressed by the plurality of protrusions42dand52d, respectively, positive electrode tabs12may be stably coupled to positive electrode lead40and negative electrode tabs22may be stably coupled to negative electrode lead50.

FIG. 6Bis a cross-sectional view of an electrode assembly constructed as the fifth embodiment according to the principles of the present invention. InFIG. 6B, asymmetrically oriented triangular protrusions42dand52dare unidirectionally inclined and formed in the direction where positive electrode tabs12and negative electrode tabs22are inserted, so that it is possible to effectively prevent positive electrode tabs12and negative electrode tabs22from being pulled out. That is, the tips of triangular protrusions42dand52dare inclined toward the ends of clips42and52to which positive electrode tabs12and negative electrode tabs22are inserted.

Pins42a,52a,42b, and52bformed in clips42and52are respectively inserted into holes12aand22aformed in the plurality of electrode tabs12and22, or protrusions42c,52c,42d, and52dformed in clips42and52respectively compress the plurality of electrode tabs12and22. As a result, electrode tabs12and22are stably coupled to electrode leads40and50, and thus the contact area between the plurality of electrode tabs12and22and electrode leads40and50increases. Therefore, the large capacity of current easily moves.

FIG. 7is an oblique view illustrating an electrode assembly constructed as the sixth embodiment according to the principles of the present invention. The plurality of positive electrode tabs12are welded to each other, and the plurality of negative electrode tabs22are welded to each other. Clips42and52are provided to cross the plurality of positive electrode tabs12and negative electrode tabs22.

Clips42and52are provided to cross the plurality of positive electrode tabs12and negative electrode tabs22so that electrode tabs12and22may be stably coupled to electrode lead40and50. The contact area between the plurality of electrode tabs12and22and electrode leads40and50increases so that the large capacity of current easily moves.

FIG. 8is an oblique view illustrating a secondary battery constructed as an embodiment according to the principles of the present invention.FIG. 9is a cross-sectional view taken along the line I11-I12ofFIG. 8.

Referring toFIGS. 8 and 9, the secondary battery constructed as an embodiment according to the principles of the present invention includes an electrode assembly100and a case200described with reference toFIGS. 1 and 2.

Case200includes a main body210accommodating electrode assembly100therein and a cover220that contacts main body210in order to seal up electrode assembly100in the state where parts of lead lines44and54are exposed to the outside. Case200has a lamination structure in which both surfaces of a metal thin film are coated with insulating resin.

Insulating tapes300for sealing up and insulation are attached to lead lines44and54between main body210and cover220.