Battery pack

A battery pack having a cover frame configured to be tightly coupled to the four side surfaces of a bare cell. The cover frame includes a rectangular cell receiving part framed by four frame parts, wherein each of the four frame parts include a support section for supporting the lower case of the bare cell, and three of the frame parts include ribs supporting the upper case of the bare cell, wherein a fourth one of the frame parts includes tab receiving grooves supporting the electrode tabs extending from the bare cell. The cover frame further includes a protection circuit module receiving part adjacent to, and separated from the cell receiving part by the fourth one of the frame parts.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on the 10 Feb. 2011 and there duly assigned Serial No. 10-2011-0011869.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to a battery pack.

2. Description of the Related Art

In general, a battery pack includes a bare cell having an electrode assembly housed in a case, and a cover frame surrounding edges of side surfaces of the bare cell. The cover frame is required to be tightly coupled to the side surfaces of the bare cell and easily formable to be manufactured in high yield.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a battery pack having a cover frame configured to be tightly coupled to side surfaces of a bare cell and easily formable to be manufactured in high yield.

According to an embodiment of the present invention, a battery pack is provided, including a bare cell, and a cover frame formed to surround top, bottom and opposing side surfaces of the bare cell, wherein the cover frame includes a rib formed only at lengthwise portions corresponding to opposing short side surfaces of the bare cell, and the rib protrude inwardly with respect to the cover frame.

The rib may be formed at one end of the cover frame in a thickness direction, and a support portion may be formed at the other end of the cover frame in the thickness direction to protrude inwardly with respect to the cover frame.

The support portion may be formed at a region other than a region where the rib is formed.

The rib may cover a portion of a top surface of the bare cell, and the support portion may cover a portion of a bottom surface of the bare cell.

The cover frame may include a first frame surrounding the top surface of the bare cell, a second frame surrounding the bottom surface of the bare cell and formed to face the first frame, and third and fourth frames surrounding short side surfaces of the bare cell and connecting one and the other ends of the first and second frames, respectively.

The ribs may be formed in the third frame and the fourth frame and may be located at the distance from the first frame and the second frame.

The battery pack may further include a rib formed in the second frame.

The rib formed in the second frame may be located at the same distance from the one and the other ends of the second frame.

One and the other ends of the support portion formed in the second frame may be connected to one ends of the support portions formed in the third and fourth frames, respectively.

The ribs may be formed in the third frame and the fourth frame and may be located to be opposite to each other in view of the location of the distance from the first frame and the second frame.

The battery pack may further include a rib formed in the second frame.

The rib formed in the second frame may be located at the same distance from the one and the other ends of the second frame.

One and the other ends of the support portion formed in the second frame may be connected to one ends of the support portions formed in the third and fourth frames, respectively.

The cover frame may be made of an elastic material.

In the battery pack according to the present invention, the cover frame can be easily formed, thereby reducing the molding cost and improving the yield.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a perspective view of a completed battery pack according to an embodiment of the present invention, andFIG. 2is an exploded perspective view of a polymer cell in the battery pack shown inFIG. 1.

Referring toFIG. 1, the battery pack100according to the embodiment of the present invention includes a bare cell10, and a cover frame20surrounding top, bottom and opposing side surfaces of the bare cell10.

Referring toFIG. 2, the bare cell10includes an electrode assembly1and a case11housing the electrode assembly10. The electrode assembly1includes a positive electrode plate2having a positive electrode active material coated on its both surfaces, a negative electrode plate4having a negative electrode active material coated on its both surfaces, and a separator3interposed between the positive electrode plate2and the negative electrode plate4. In addition, a positive electrode tab5protruding a predetermined length and functioning as a positive electrode is attached to the positive electrode plate2. Further, a negative electrode tab6protruding a predetermined length and functioning as a negative electrode is attached to the negative electrode plate4. An insulation tape7may further be provided in the positive electrode tab5and the negative electrode tab6to insulate each of the positive electrode tab5and the negative electrode tab6from the case11, respectively. The positive electrode tab5and the negative electrode tab6are drawn out to the outside through one side surface of the case11and are electrically connected to a protection circuit module (PCM) (not shown), respectively.

The case11is folded at the center of a layer forming the case11to then be divided into a lower case12and an upper case13. The lower case12has a receiving section12aformed by a pressing process to receive the electrode assembly1. The electrode assembly1is received in the receiving section12aand the lower case12is covered by the upper case13, followed by thermally welding edges of the receiving section12a, thereby completing the bare cell10.

In the present invention, a surface of the bare cell10from which the electrode tabs5and6extend is referred to as a top surface, and a surface opposite to and facing the top surface is referred to as a bottom surface. In addition, a surface connecting one short side of the top surface to one short side of the bottom surface is referred to as a first short side surface, and a surface connecting the other short side of the top surface to the other short side of the bottom surface is referred to as a second short side surface. Further, a surface connecting one long side of the top surface to one long side of the bottom surface is referred to as a first long side surface, and a surface, formed by upper case13, connecting the other long side of the top surface to the other long side of the bottom surface is referred to as a second long side surface.

FIG. 3Ais a perspective view of a cover frame in the battery pack shown inFIG. 1, andFIG. 3Bis a plan view of the cover frame shown inFIG. 3A.

Referring toFIGS. 3A and 3B, the cover frame20includes a first frame21, a second frame22, a third frame23and a fourth frame24surrounding the top surface (from which the electrode tabs5and6extend), bottom surface and opposing short side surfaces of the bare cell10. Thus, the bare cell10is received in a cell receiving section20asurrounded by the first to fourth frames21,22,23and24. The cover frame20may further include a PCM (protection circuit module) receiving section20badjacent to and separated from the cell receiving section20aby first frame21. In addition, the cover frame20may be made of an elastic material such as rubber. However, the present invention does not limit the material of the cover frame20to rubber, and any elastic material that is somewhat deformable can be used.

The first frame21includes a first support portion21a(FIG. 3B) formed at a thicknesswise bottom end (edge) and tab receiving grooves21b(FIG. 3A) formed at a thicknesswise top end (edge).

The first support portion21ais formed along at least a lengthwise a portion of the first frame21and extends from the thicknesswise bottom end of the first frame21toward the inside of the cover frame20, that is, toward the cell receiving section20a. Thus, the first support portion21asupports the first long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, in order to increase the supporting capacity of the first support portion21a, the first support portion21ais preferably formed from a lengthwise end of the first frame21to the other lengthwise end of the first frame21.

The tab receiving grooves21bare formed at locations corresponding to the positive electrode tab5and the negative electrode tab6of the bare cell10accommodated in the cell receiving section20a. Therefore, the positive electrode tab5and the negative electrode tab6are drawn out toward the PCM receiving section20bthrough the tab receiving grooves21b, respectively, for electrical connection to the PCM (not shown) accommodated in the PCM receiving section20b.

The second frame22includes a second support portion22aformed at a thicknesswise bottom end and a first rib22bformed at a thicknesswise top end.

The second support portion22ais formed along at least a lengthwise portion of the second frame22and extends from the thicknesswise bottom end of the second frame22toward the cell receiving section20a. Thus, the second support portion22asupports the first long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, in order to increase the supporting capacity of the second support portion22a, the second support portion22ais preferably formed from a lengthwise end of the second frame22to the other lengthwise end of the second frame22.

The first rib22bis formed along at least a lengthwise portion of the second frame22and extends from the thicknesswise top end of the second frame22toward the cell receiving section20a. Thus, the first rib22bsupports the second long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. The configuration in which the first rib22bis formed in the second frame22provides for a superb fixing effect particularly in a wide, thin battery pack having an increased long side surface of the bare cell10. In addition, the first rib22bis preferably formed at a central portion of the top end of the second frame22, except that the second support portion22amay not be formed at a region corresponding to a region where a first rib22b, which will later be described, is formed. The second support portion22ais for the purpose of stably fixing the bare cell10accommodated in the cell receiving section20aof the cover frame20.

As shown inFIG. 3B, when the cover frame20is viewed downwardly from the top, the second support portion22aand the first rib22bare preferably formed so as not to overlap each other. That is to say, the second support portion22ais preferably not formed in an area of the lengthwise region of the second frame22corresponding to a region where the first rib22bis formed. This simplifies a molding structure, thereby facilitating fabrication of the cover frame20by injection molding and improving the yield of the battery pack100.

The third frame23includes a third support portion23aformed at a thicknesswise bottom end and a second rib23bformed at a thicknesswise top end.

The third support portion23ais formed along at least a lengthwise portion of the third frame23and extends from the thicknesswise bottom end of the third frame23toward the cell receiving section20a. Thus, the third support portion23asupports the first long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, in order to increase the supporting capacity of the third support portion23a, the third support portion23ais preferably formed from a lengthwise end of the third frame23to the other lengthwise end of the third frame23, except that the third support portion23amay not be formed at a region corresponding to a region where a second rib23b,which will later be described, is formed. In addition, one end of the third support portion23ais preferably connected to one end of the first support portion21aand the other end the third support portion23ais preferably connected to one end of the second support portion22a,which is for the purpose of increasing the supporting capacity of the support portions21a,22aand23a.

The second rib23bis formed along at least a lengthwise portion of the third frame23and extends from the thicknesswise top end of the third frame23toward the cell receiving section20a. Thus, the second rib23bsupports the second long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, the second rib23bis preferably formed at a central portion of the top end of the third frame23. This is for the purpose of stably fixing the bare cell10accommodated in the cell receiving section20aof the cover frame20while facilitating insertion of the bare cell10into the cell receiving section20aof the cover frame20.

As shown inFIG. 3B, when the cover frame20is viewed downwardly from the top, the third support portion23aand the second rib23bare preferably formed so as not to overlap each other. That is to say, the third support portion23amay not be formed in an area of the lengthwise region of the third frame23corresponding to a region where the second rib23bis formed. Thus, fabrication of the cover frame20by injection molding is facilitated, thereby improving the yield of the battery pack100.

The second rib23bis preferably shorter than the third support portion23ain a lengthwise direction of the third frame23. This is for the purpose of facilitating insertion of the bare cell10into the cell receiving section20afrom the top portion of the cover frame20. That is to say, in order to insert the bare cell10into the cell receiving section20a, it is necessary for the second rib23bto elastically deform upwardly. Therefore, if the second rib23bis formed to be longer than the third support portion23a, it is not easy to insert the bare cell10into a region between the second rib23band the third support portion23a.

The fourth frame24includes a fourth support portion24aformed at a thicknesswise bottom end and a third rib24bformed at a thicknesswise top end.

The fourth support portion24ais formed along at least a lengthwise portion of the fourth frame24and extends from the thicknesswise bottom end of the fourth frame24toward the cell receiving section20a. Thus, the fourth support portion24asupports the first long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, in order to increase the supporting capacity of the fourth support portion24a, the fourth support portion24ais preferably formed from a lengthwise end of the fourth frame24to the other lengthwise end of the fourth frame24, except that the fourth support portion24amay not be formed at a region corresponding to a region where a third rib24b, which will later be described, is formed. In addition, one end of the fourth support portion24ais preferably connected to one end of the first support portion21aand the other end the fourth support portion24ais preferably connected to one end of the second support portion22a, which is for the purpose of increasing the supporting capacity of the support portions21a,22aand24a.

The third rib24bis formed along at least a lengthwise portion of the fourth frame24and extends from the thicknesswise top end of the fourth frame24toward the cell receiving section20a. Thus, the third rib24bsupports the second long side surface of the bare cell10accommodated inside the cell receiving section20aof the cover frame20. In addition, the second rib24bis preferably formed at a central portion of the fourth frame24. This is for the purpose of stably fixing the bare cell10accommodated in the cell receiving section20aof the cover frame20while facilitating insertion of the bare cell10into the cell receiving section20aof the cover frame20.

As shown inFIG. 3B, when the cover frame20is viewed downwardly from the top, the fourth support portion24aand the third rib24bare preferably formed so as not to overlap each other. That is to say, the fourth support portion24ais preferably not formed in an area of the lengthwise region of the fourth frame24corresponding to a region where the third rib24bis formed. This facilitates fabrication of the cover frame20by injection molding, thereby improving the yield of the battery pack100.

The third rib24bis preferably shorter than the fourth support portion24ain a lengthwise direction of the fourth frame24. This is for the purpose of facilitating insertion of the bare cell10into the cell receiving section20afrom the top portion of the cover frame20. That is to say, in order to insert the bare cell10into the cell receiving section20a, it is necessary for the third rib24bto elastically deform upwardly. Therefore, if the third rib24bis formed to be longer than the fourth support portion24a, it is not easy to insert the bare cell10into a region between the third rib24band the fourth support portion24a.

As described above, the ribs,22b,23band24bare centrally located along second, third and fourth frames22,23and24, and each support section22a,23aand24aincludes a gap therein formed at a central region of second, third and fourth frames22,23and24corresponding to a region where each the ribs22b,23band24bare formed.

Next, a cover frame in a battery pack according to another embodiment of the present invention will be described with reference toFIGS. 4A to 4C.FIG. 4Ais a perspective view of a cover frame in a battery pack according to another embodiment of the present invention, andFIGS. 4B and 4Care alternative plan views of the cover frame shown inFIG. 4A.

Referring toFIGS. 4A and 4B, the cover frame30of the battery pack according to the embodiment of the present invention includes a first frame31, a second frame32a third frame33and a fourth frame34surrounding the top surface, the bottom surface and opposing side surfaces of the bare cell10. Thus, the bare cell10is received in a cell receiving section30asurrounded by the first to fourth frames31,32,33and34. The cover frame30may further include a PCM receiving section30bopposite to, and separated from, the cell receiving section30aby the first frame31.

The first frame31includes a first support portion31aformed at a thicknesswise bottom end (edge) and tab receiving grooves31bformed at a thicknesswise top end (edge).

The second frame32includes a second support portion32aformed at a thicknesswise bottom end and a first rib32bformed at a thicknesswise top end.

The third frame33includes a third support portion33aformed at a thicknesswise bottom end and a second rib33bformed at a thicknesswise top end.

The fourth frame34includes a fourth support portion34aformed at a thicknesswise bottom end and a third rib34bformed at a thicknesswise top end.

The cover frame30of the battery pack according to the embodiment of the present invention is substantially the same as the cover frame20of the battery pack100, except for locations where the second rib33band the third rib34bare formed, and corresponding where regions of the third support portion33aand the fourth support portion34aare not formed. Therefore, the cover frame30of the battery pack according to the embodiment of the present invention will be described with regard to the third support portion33a, the second rib33b, the fourth support portion34aand the third rib34b, and repeated explanations of the other components will not be given.

The second rib33bmay be formed at a location closer to the first frame31from a central portion of the third frame33. In this case, the third rib34bmay be formed at a location closer to the second frame32from a central portion of the fourth frame34. As described above, the third support portion33aand the fourth support portion34amay not be formed at corresponding locations where the second rib33band the third rib34bare formed. That is to say, when the cover frame30is viewed downwardly from the top, the third support portion33aand the second rib33bare preferably formed so as not to overlap each other, and the fourth support portion34aand the third rib3bbare preferably formed so as not to overlap each other.

In addition, referring toFIG. 4C, the second rib33bmay be formed at a location closer to the second frame32from a central portion of the third frame33. In this case, the third rib34bmay be formed at a location closer to the first frame31from a central portion of the fourth frame34. As described above, the third support portion33aand the fourth support portion34amay not be formed at corresponding locations where the second rib33band the third rib34bare formed. That is to say, when the cover frame30is viewed downwardly from the top, the third support portion33aand the second rib33bare preferably formed so as not to overlap each other, and the fourth support portion34aand the third rib3bbare preferably formed so as not to overlap each other.

As described above, when the second rib33band the third rib34bare offset from the central portion of third and fourth frames33and34, the bare cell10can be more easily inserted into the cover case30, and each support section32a,33aand34aincludes a gap therein formed at a region corresponding to a region where each the ribs32b,33band34bare formed.