Battery pack

A battery pack that includes a bare cell, a protection circuit module arranged on the bare cell and a case arranged on the protection circuit module, wherein the protection circuit module and the case include coupling members to couple the protection circuit module to the case.

CLAIM OF PRIORITY

This application makes reference to, incorporate the same herein, and claims all benefits accruing, and claims all benefits accruing under 35 U.S.C. §119 from an application for BATTERY PACK earlier filed in the Korean Intellectual Property Office on 13 Jan. 2009 and there duly assigned Serial No. 10-2009-0002579.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a design for a battery pack.

2. Description of the Related Art

A bare cell, which includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator, supplies electrical power to an external electronic device, and is re-used through repeated charge-discharge cycles. A protection circuit module is responsible for protecting a secondary battery from overcharge and overcurrent and preventing battery deterioration caused by overdischarge.

A bare cell and a protection circuit module are assembled into a pack along with a case. At this time, it is important to configure the pack to have a strong and compact structure. Often, a holder is required to support the protection circuit module within a battery. These extra parts increase the complexity of the manufacture of the battery pack and increase the costs of the battery pack. What is needed is a design for a battery pack that provides greater structural strength within the battery pack while reducing the costs and complexity of producing the battery pack.

SUMMARY OF THE INVENTION

The present invention provides a battery pack wherein a protruding portion of a protection circuit module is fitted into an aperture of a case. Therefore, the battery pack exhibits an improved structural strength and does not require a holder, thereby leading to reduced manufacturing costs and processes.

According to an aspect of the present invention, there is provided a battery pack including a bare cell, a protection circuit module arranged on the bare cell and a case arranged on the protection circuit module, wherein the protection circuit module and the case include coupling members to couple the protection circuit module to the case.

The protection circuit module can include a protection circuit board arranged on the bare cell and separated from the bare cell by a distance, the protection circuit board including first and second short sides and first and second long sides and first and second tabs respectively arranged on bottom surfaces of the first and second short sides of the protection circuit board. The first and second tabs respectively can include first and second protruding portions that protrude out of each of the first and second long sides of the protection circuit board. The case can include first and second apertures receiving the first and second protruding portions, respectively. The first and second protruding portions and the first and second apertures can be the coupling members. The case can include a first surface facing upward and second and third surfaces extending downward from the first surface, the first and second apertures are arranged in each of the second and third surfaces, respectively.

The first and second tabs can have a square shape. Each of the first and second protruding portions can have a tapered end. The protection circuit module can also include a dummy tab arranged between the first and second tabs. The dummy tab can include a dummy protruding portion that protrudes out of each of the first and second long sides of the protection circuit board. The case can also include a dummy aperture receiving the dummy protruding portion. The dummy protruding portion and the dummy aperture can be the coupling members. The case can include a first surface facing upward and second and third surfaces extending downward from the first surface, the dummy aperture being arranged in each of the second and third surfaces. The dummy tab can have a square shape. The dummy protruding portion can have a tapered end. The protection circuit module can be arranged on a surface of the bare cell.

The battery pack can also include an insulating tape arranged between the bare cell and the protection circuit module. The protection circuit module can also include first and second lead plates connected to the first and second tabs, respectively. The first and second tabs can be electrically connected to the first and second lead plates, respectively. The first lead plate can be electrically connected to an electrode terminal arranged on a surface of the bare cell, and the second lead plate can be electrically connected to the opposite surface of the bare cell. The first and second lead plates can be connected to a cap plate of the bare cell. The first lead plate can be electrically connected to the cap plate of the bare cell, and the protection circuit module can also include a negative electrode lead plate electrically connected to an electrode terminal of the bare cell.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described more fully hereinafter with reference to the accompanying drawings in which preferred embodiments of the invention are shown. The invention can, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Throughout the specification, the same reference numerals refer to the same elements. Hereinafter, battery packs according to various exemplary embodiments of the present invention will be described in detail with reference to the drawings.

Turning now toFIGS. 1 through 5,FIGS. 1 and 2are respectively a schematic perspective view and an exploded perspective view of a battery pack10according to the first embodiment of the present invention, andFIGS. 3 through 5are respectively a top view, a bottom view, and a side view of a protection circuit module200of the battery pack10according to the first embodiment of the present invention.

Referring toFIGS. 1 through 5, the battery pack10can include a bare cell100, the protection circuit module200, a case300, a lateral tape400, and a label500. An insulating tape600can be further arranged between the bare cell100and the protection circuit module200. The protection circuit module200and the case300can include coupling members for connection therebetween. In detail, the battery pack10is configured so that protruding portions of the protection circuit module200are fitted into apertures of the case300, thereby leading to a higher coupling force between the protection circuit module200and the case300, resulting in improved structural strength of the battery pack10. Further, due to such fitting between the protruding portions of the protection circuit module200and the apertures of the case300, the battery pack10does not require a holder for supporting the protection circuit module200on a side surface of the bare cell100, thereby leading to reduced manufacturing costs and processes.

The bare cell100can include a can110, an electrode assembly (not shown), and a cap assembly (not shown) that are combined to each other. The electrode assembly is inserted into the can110via an open side of the can110, and the open side is sealed by the cap assembly. The bare cell100, which is an essential element of the chargeable/dischargeable battery pack10, includes a positive electrode and a negative electrode for charge-discharge cycling of the battery pack10. InFIG. 2, a surface that an electrode terminal122is arranged defines a top surface (right ofFIG. 2), a surface that the top surface is opposite defines a bottom surface (left ofFIG. 2), a surface that the protection circuit module200is arranged defines a side surface (top ofFIG. 2), and a surface that the side surface is opposite defines another side surface (bottom ofFIG. 2).

The can110can have substantially a rectangular parallelepiped shape. A top side of the can110can be open and side surfaces thereof can be curved. The can110can be made out of a light metal material such as aluminum (Al), and can serve as the positive terminal. The electrode assembly (as will be described later) and an electrolyte solution (not shown) can be inserted into the open side of the can110.

The electrode assembly can include a positive electrode plate (not shown), a negative electrode plate (not shown), and a separator (not shown) arranged between the two electrode plates. The electrode assembly can be produced by winding the positive electrode plate, the negative electrode plate, and the separator into a jelly roll-type structure. The electrode assembly can be inserted into the can110via the opening of the can110.

The cap assembly can include a cap plate121, an electrode terminal122, a gasket123, an insulating plate (not shown), and a terminal plate (not shown). The cap assembly can be combined with the electrode assembly along with an insulating case (not shown) to seal the open side of the can110. The electrode terminal122can serve as a negative terminal.

The protection circuit module200can include a protection circuit board210, a protection circuit device220, a charge-discharge terminal230, a first tab240, a second tab250, a first lead plate260, and a second lead plate270. The first tab240and the second tab250include coupling members for connecting the protection circuit module200to the case300. The protection circuit module200can further include a positive temperature coefficient (PTC) device (not shown) arranged below the protection circuit board210or at the first lead plate260.

The protection circuit board210can be arranged on the bare cell100and be separated from the bare cell100by a predetermined distance. In more detail, the protection circuit board210can be arranged on a side surface (inFIG. 2) of the bare cell100, and can have substantially a rectangular plate shape. A conductive metal pattern can be present on the protection circuit board210, and can be electrically connected to the protection circuit device220, the charge-discharge terminal230, the first tab240, and the second tab250. The protection circuit board210can be a printed circuit board (PCB). When the protection circuit board210is viewed from top as inFIG. 3, two short sides are defined as a “first short side210a” and a “second short side210b”, and two long sides as a “first long side210c” and a “second long side210d”.

The protection circuit device220can be arranged between the bottom surface of the protection circuit board210and the side surface of the bare cell100, as viewed inFIGS. 2 through 4. The protection circuit device220is responsible for protecting the bare cell100by monitoring information about the charge-discharge state, current, voltage, temperature and other details of the bare cell100. The protection circuit device220can be electrically connected to the conductive metal pattern on the protection circuit board210.

The charge-discharge terminal230is arranged on the protection circuit board210and can serve as an electrical connector that connects the battery pack10to an external electronic device (not shown). The first tab240can be arranged below the first short side210aof the protection circuit board210, and can have substantially a square plate shape. The first tab240is designed to partially protrude out of each of the first long side210cand the second long side210dof the protection circuit board210, and the protruding portions of the first tab240are defined as a “first protruding portion241”. In this respect, the first tab240can include a pair of first protruding portions241. The first tab240can be made out of nickel or nickel alloy and can be electrically connected to the conductive metal pattern of the protection circuit board210.

The second tab250can be arranged below the second short side210bof the protection circuit board210, and can have substantially a square plate shape. The second tab250is designed to partially protrude out of each of the first long side210cand the second long side210dof the protection circuit board210, and the protruding portions of the second tab250are defined as a “second protruding portion251”. In this respect, the second tab250can include a pair of second protruding portions251. The second tab250can be made out of nickel or nickel alloy, and can be electrically connected to the conductive metal pattern on the protection circuit board210.

The first lead plate260can be arranged at the first short side210aof the protection circuit board210. The first lead plate260can be folded at an angle of 90 degrees at a contact edge of the top and side surfaces of the bare cell100, as viewed inFIG. 2. An end of the first lead plate260can be electrically connected to a bottom surface of the first tab240through welding, and the other end can be electrically connected to the electrode terminal122arranged on a top surface of the bare cell100. The electrode terminal122is connected to the negative electrode plate of the electrode assembly through welding, and thus has a negative polarity. Thus, the first lead plate260and the first tab240electrically connected to the electrode terminal122also have a negative polarity. The can110and the cap plate121have a positive polarity. In this regard, in order to prevent a short circuit between the can110or the cap plate121and the first lead plate260, the insulating tape600can be arranged between the bare cell100and the protection circuit module200.

The second lead plate270can be arranged at the second short side210bof the protection circuit board210. The second lead plate270can be folded at an angle of 90 degrees at a contact edge of the bottom and side surfaces of the bare cell100, as viewed inFIG. 2. An end of the second lead plate270can be electrically connected to a bottom surface of the second tab250through welding, and the other end can be electrically connected to the bottom surface of the bare cell100. The positive electrode plate of the electrode assembly can be electrically connected to the cap plate121through welding. The can110is electrically connected to the cap plate121through welding, and thus, has a positive polarity. Thus, the second lead plate270and the second tab250have a positive polarity.

The case300is arranged on the protection circuit module200, and more specifically, it can be arranged to surround the protection circuit module200and the top and bottom surfaces of the bare cell100. The case300can include a first section310corresponding to the protection circuit board210, and second and third sections320and330respectively corresponding to the top and bottom surfaces of the bare cell100. In more detail, the first section310includes a first surface311which corresponds to a top surface of the protection circuit module200and has a rectangular shape. The first section310also includes second and third surfaces312and313that extend downward from two long sides of the first surface311and also have a rectangular shape. The first surface311of the first section310of the case300can have a charge-discharge terminal receiving aperture311a(seeFIG. 1) corresponding to the charge-discharge terminal230of the protection circuit module200so that the charge-discharge terminal230can be exposed to outside through the charge-discharge terminal receiving aperture311a.

Each of the second and third surfaces312and313of the first section310of the case300can have a first aperture312aand a second aperture312bwhich respectively correspond to the first protruding portion241and the second protruding portion251of tabs240and250. In more detail, the first aperture312aand the second aperture312bcan perforate the second surface312to respectively correspond to the first protruding portion241and the second protruding portion251, and similarly, the first aperture312aand the second aperture312bcan also be formed in the third surface313to respectively correspond to the first protruding portion241and the second protruding portion251. The first and second apertures312aand312bcan have shapes corresponding to the first and second protruding portions241and251so that the first and second protruding portions241and251can be fitted into the first and second apertures312aand312b.

The lateral tape400can be arranged on the top and bottom surfaces of the bare cell100to cover the second and third sections320and330of the case300, thereby providing a higher coupling force between the case300and the bare cell100. The label500is responsible for covering the bare cell100and the case300and protects the bare cell100and the protection circuit module200from external impact.

Hereinafter, the connection relationship between the first protruding portion241of the first tab240and the first aperture312aas well as the connection relationship between the second protruding portion251of the second tab250and the second aperture312bwill be described in detail. The connection relationship between the first protruding portion241and the first aperture312aand the connection relationship between the second protruding portion251and the second aperture312bcan be explained with the same principle. Thus, only the connection relationship between the first protruding portion241and the first aperture312awill now be described.

FIGS. 6 and 7are respectively a partial perspective view and a partial enlarged view of the battery pack10ofFIG. 2. Referring toFIGS. 6 and 7, together withFIGS. 1 through 5, as described above, the first tab240of the protection circuit module200can have the first protruding portion241which protrudes out of each of the first and second long sides210cand210dof the protection circuit board210. The second and third surfaces312and313of the first section310of the case300can have the first aperture312awhich has a shape corresponding to the first protruding portion241and at a corresponding location of the first protruding portion241. The first protruding portion241and the first aperture312acan serve as coupling members for connecting the protection circuit module200to the case300.

As described above, the first protruding portion241and the first aperture312aare coupled to each other. Specifically, the first protruding portion241is forcedly fitted into the first aperture312aso that the protection circuit module200and the case300can be joined together firmly. An end of the first protruding portion241facing the first aperture312acan be tapered in order to facilitate such fitting between the first protruding portion241and the first aperture312a.

In the battery pack10according to the first embodiment of the present invention, the first protruding portion241of the protection circuit module200is fitted into he first aperture312aof the case300, thereby leading to a higher coupling force between the protection circuit module200and the case300, resulting in the improved structural strength of the battery pack10. Here, the first protruding portion241is a predetermined protruding portion of the first tab240electrically connected to the first lead plate260of the protection circuit module200. That is, the first tab240, which is an essential element for electrical connection between the bare cell100and the protection circuit module200, can be configured to protrude out of the first and second long sides210cand210dof the protection circuit board210, thereby enabling easy formation of a coupling member for connection between the case300and the protection circuit module200. Therefore, it is not necessary to provide a separate coupling member. In the conventional battery pack, a coupling member is separately provided at a protection circuit module to enhance the structural strength of the battery pack. Since the present invention eliminates the need for this separate coupling member, manufacturing costs and manufacturing processes for the battery pack10can be reduced.

It is also noted that a conventional battery pack also requires a holder between a protection circuit module and a bare cell in order to stably support the protection circuit module when a protection circuit module is arranged at a side surface of the bare cell. However, in the battery pack10according to the current embodiment of the present invention, the protruding portions of the protection circuit module200are fitted into the apertures of the case300, and thus the protection circuit module200can be firmly supported by the case300. Therefore, the use of a holder is not required, thereby further reducing manufacturing costs and further simplifying the process of making the battery pack10.

Hereinafter, a battery pack20according to a second embodiment of the present invention will be described with reference toFIGS. 8 through 10. The battery pack20of the second embodiment of the present invention is substantially the same as the battery pack10of the first embodiment of the present invention except that a dummy tab and a dummy aperture for the protection circuit module and the case, respectively are further present. Therefore, only the structures and functions of the dummy tab and the dummy aperture will now be described.

FIG. 8is an exploded perspective view of the battery pack20, andFIGS. 9 and 10are respectively a bottom view and a side view of a protection circuit module200′ of the battery pack20. Referring toFIGS. 8 through 10, the battery pack20further includes a dummy tab280and a dummy aperture312c. The dummy tab280can be arranged at a central portion of a bottom surface of a protection circuit board210. Specifically, the dummy tab280can be arranged between a first tab240and a second tab250at a central portion of bottom surface of the protection circuit board210, and can have substantially a square plate shape. The dummy tab280partially protrudes out of each of first and second long sides210cand210dof the protection circuit board210, and the protruding portions of the dummy tab280is defined as “a dummy protruding portion281”. In this respect, the dummy protruding portion281is actually two protruding portions. The dummy tab280can be made out of nickel or nickel alloy. The dummy tab280is simply welded to a bottom surface of the protection circuit board210without being electrically connected to a conductive metal pattern of the protection circuit board210.

The dummy aperture312ccan be arranged in each of second and third surfaces312and313of the case300′ to correspond to the dummy protruding portion281. The dummy aperture312ccan have a shape corresponding to the dummy protruding portion281so that the dummy protruding portion281can be fitted into the dummy aperture312c. The dummy protruding portion281and the dummy aperture312ccan serve as coupling members for the connection between the protection circuit module200′ and the case300′.

As described above, the dummy protruding portion281and the dummy aperture312care coupled to each other. Specifically, the dummy protruding portion281is forcedly fitted into the dummy aperture312cso that the protection circuit module200′ and the case300′ can be joined together firmly. An end of the dummy protruding portion281facing the dummy aperture312ccan be tapered in order to facilitate such fitting between the dummy protruding portion281and the dummy aperture312c.

According to the second embodiment of the present invention, when a dummy protruding portion281is additionally fitted into a dummy aperture312c, the coupling force between a protection circuit module200′ and a case300′ is much stronger as compared with the first embodiment, thereby resulting in still more improved structural strength of a battery pack20.

Hereinafter, a battery pack30according to a third embodiment of the present invention will now be described with reference toFIGS. 11 and 12. The battery pack30of the third embodiment of the present invention is different from the battery packs10and20of the first and second embodiments in terms of the positioning and interconnection between a protection circuit module and a bare cell, and the structures of the protection circuit module and the case. Thus, the battery pack30will now be described in terms of the differences between it and the battery packs10and20.

FIG. 11is an exploded perspective view of the battery pack30andFIG. 12is a top view of a protection circuit module700of the battery pack30. Referring toFIGS. 11 and 12, the battery pack30can include a bare cell100, the protection circuit module700, and a case800. The battery pack30can further include a label (not shown) which covers the bare cell100and the case800to protect the bare cell100and the protection circuit module700from external impact. Here, the bare cell100is substantially the same as those of the previous embodiments, and thus, a description thereof will be omitted.

The protection circuit module700can include a protection circuit board710, a protection circuit device (not shown), a charge-discharge terminal730, a first tab740, a second tab750, a first lead plate760, a second lead plate770, and a negative electrode lead plate (not shown). The first and second tabs740and750of the protection circuit module700include first protruding portion741and second protruding portion751as coupling members that connect the protection circuit module700to the case800.

The protection circuit board710can be arranged on the bare cell100to be spaced apart from the bare cell100by a predetermined distance. In more detail, the protection circuit board710can be arranged above the bare cell100and can have substantially a rectangular plate shape. A conductive metal pattern can be present on the protection circuit board710and can be electrically connected to the protection circuit device, the charge-discharge terminal730, the first tab740, and the second tab750. The protection circuit board710can be a PCB. When the protection circuit board710is viewed from the top as inFIG. 12, two short sides are defined as a “first short side710a” and a “second short side710b”, and two long sides as a “first long side710c” and a “second long side710d”.

The protection circuit device can be arranged between a bottom surface of the protection circuit board710and the top surface (inFIG. 12) of the bare cell100. The protection circuit device is responsible for protecting the bare cell100by monitoring information about the charge-discharge state, current, voltage, temperature and other details of the bare cell100. The protection circuit device can be electrically connected to the conductive metal pattern of the protection circuit board710.

The charge-discharge terminal730is arranged on the protection circuit board710and can serve as an electrical connector for connecting the battery pack30to an external electronic device (not shown). The first tab740can be arranged on a bottom surface at the first short side710aof the protection circuit board710, and can have substantially a square plate shape. The first tab740can be designed to partially protrude out of each of the first and second long sides710cand710dof the protection circuit board710, and the protruding portions of the first tab740is defined as “a first protruding portion741”. In this respect, the first protruding portion is actually a pair of first protruding portions. The first tab740can be made out of nickel or nickel alloy, and be electrically connected to the conductive metal pattern on the protection circuit board710.

The second tab750can be arranged on a bottom surface at the second short side710bof the protection circuit board710, and have substantially a square plate shape. The second tab750can be designed to partially protrude out of each of the first and second long sides710cand710dof the protection circuit board710, and the protruding portions of the second tab750is defined as “a second protruding portion751”. In this respect, second protruding portion751actually includes a pair of protruding portions. The second tab750can be made out of nickel or nickel alloy and be electrically connected to the conductive metal pattern on the protection circuit board710.

The first lead plate760can be arranged at the first short side710aof the protection circuit board710. An end of the first lead plate760can be electrically connected to the first tab740through welding, and the other end can be electrically connected to a cap plate (not shown) of the bare cell100. A positive electrode plate (not shown) of an electrode assembly (not shown) of the bare cell100is electrically connected to the cap plate through welding, and thus, the cap plate has a positive polarity. Thus, the first lead plate760and the first tab740have a positive polarity.

The second lead plate770can be arranged at the second short side710bof the protection circuit board710. One end of the second lead plate710can be connected to a bottom surface of the second tab750through welding, and the other end can be connected to the cap plate of the bare cell100through welding. The second lead plate770can be electrically connected to the cap plate, and thus, can serve as an electrical conductor, like the first lead plate760. On the other hand, the second lead plate770can also serve as a dummy lead plate for stably holding the protection circuit module700on the bare cell100by simply being connected to the bottom surface of the protection circuit board710. The negative electrode lead plate of the protection circuit board710can be arranged to correspond to an electrode terminal (not shown) of the bare cell100so as to be electrically connected to the electrode terminal.

The case800can be arranged on the protection circuit module700to surround the protection circuit module700and the top surface (inFIG. 11) of the bare cell100. The case800can include a first surface811, which corresponds to the top surface of the protection circuit module700and has a rectangular shape, and second and third surfaces812and813which extend downward from two long sides of the first surface811and also have a rectangular shape. A charge-discharge terminal receiving aperture can be arranged on the first surface811of the case800to correspond to the charge-discharge terminal730of the protection circuit module700. The charge-discharge terminal730can be exposed to outside via the charge-discharge terminal receiving aperture.

Each of the second and third surfaces812and813of the case800can include a first aperture812aand a second aperture812bcorresponding to the first and second protruding portions741and751, respectively. In more detail, the first aperture812aand the second aperture812bcan perforate the second surface812to respectively correspond to the first protruding portion741and the second protruding portion751, and similarly, the first aperture812aand the second aperture812bcan also penetrate the third surface813of case800to respectively correspond to the first protruding portion741and the second protruding portion751. The first and second apertures812aand812bcan have shapes corresponding to the first and second protruding portions741and751so that the first and second protruding portions741and751can be fitted into the first and second apertures812aand812b.

The first and second protruding portions741and751and the first and second apertures812aand812bcan serve as coupling members for connecting the protection circuit module700to the case800. The first and second protruding portions741and751can be coupled to the first and second apertures812aand812b, respectively. Specifically, the first and second protruding portions741and751can be forcedly fitted into the first and second apertures812aand812bso that the protection circuit module700and the case800can be joined together firmly.

In the battery pack30according to the third embodiment of the present invention, the first and second protruding portions741and751of the protection circuit module700are fitted into the first and second apertures812aand812bof the case800, thereby leading to a higher coupling force between the protection circuit module700and the case800, resulting in the improved structural strength of the battery pack30. Here, the first and second protruding portions741and751are protruding portions of the first and second tabs740and750, the first and second tabs740and750being electrically connected to the first and second lead plates760and770of the protection circuit module700. That is, the first and second tabs740and750, which are essential elements for electrical connection between the bare cell100and the protection circuit module700, can be configured to protrude out of the first and second long sides of the protection circuit board710, thereby enabling easy formation of coupling members for connection between the case800and the protection circuit module700. Therefore, it is not necessary to separately provide a coupling member as in the conventional battery pack to enhance the structural strength of the battery pack. By being able to provide coupling members without having to include a separate element for the coupling, manufacturing simplicity is increased and manufacturing costs are reduced.

As is apparent from the above description, according to the inventive battery pack, a protruding portion of a protection circuit module is fitted into an aperture of a case, thereby leading to a higher coupling force between the protection circuit module and the case, resulting in improved structural strength of a battery pack. Further, such fitting between a protruding portion of a protection circuit module and an aperture of a case enables the omission of a holder that is commonly used to support a protection circuit module on a surface of a bare cell, thereby leading to reduced manufacturing costs and processes. By incorporating the coupling members into the design of the battery pack without requiring the addition of additional parts, simplicity in design and production is further improved and manufacturing costs are further reduced.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes can be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.