KR20090026650A - Protection circuit board and battery pack using the same - Google Patents

Abstract

A protection circuit board is provided to improve the reliability of bending and twisting generated by external pressure, to simplify a structure of pack and to facilitate the binding of the protection circuit board and the bare cell. A protection circuit board is connected to a bare cell(500) and has an electric device for protecting the bare cell in overcharging, overdischarging, and applying excess current. The protection circuit board comprises a lead plate having connection grooves. The lead plate has U shape. The protection circuit board comprises grooves(650) in the position corresponding to that of the lead plate.

Description

Protection circuit board and battery pack having the same {Protection circuit board and battery pack using the same}

The present invention relates to a protective circuit board and a battery pack having the same, and to the bending and twisting caused by external pressure by changing the structure of the lead plate connecting the bare cell and the protective circuit board. The present invention relates to a protection circuit board having a lead plate having an improved structure to improve reliability and simplify the pack structure and to facilitate coupling of a bare cell and a protection circuit board, and a battery pack having the same.

As miniaturization and light weight of electronic / electrical devices have recently been rapidly advanced, the necessity for miniaturization and high capacity of batteries used as driving power sources thereof is increasing. In particular, the lithium secondary battery has an operating voltage of 3.6 V or more, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic / electrical equipment, and rapidly expands in terms of high energy density per unit weight. It is becoming a trend.

However, when the lithium secondary battery is charged to 4.5V or more, the electrolyte inside the battery is decomposed, thereby forming a gas, which leads to an unstable state. The gas formed increases the internal pressure of the cell, which may involve leakage of the electrolyte. In addition, when the battery is discharged below a certain voltage, copper, which is a current collector of the negative electrode, begins to melt into the electrolyte, thereby degrading the performance of the battery.

In addition, there is a problem in that, due to the chemical characteristics of the battery, there is a high risk of ignition, rupture, explosion, and thereby a fire occurring under an overcurrent situation due to overcharge, overdischarge, or short between terminals.

Accordingly, a secondary battery generally includes a protective circuit board together with a bare cell. The bare cell houses an electrode assembly consisting of a positive electrode, a negative electrode, and a separator in a can made of steel, aluminum, or an aluminum alloy, and caps the can. After finishing with the assembly, it is formed by injecting and sealing the electrolyte into the can.

The protection circuit board is to secure safety and reliability by preventing safety accidents caused by overcharging, overdischarging, overcurrent, etc. of the secondary battery. After the formation of the bare cell, the protection circuit board is electrically connected to the outside of the bare cell.

The protective circuit board includes a protective circuit element and an electrode terminal on one surface of a printed circuit board on which a wiring pattern is formed, and an external connection terminal for connecting to an electronic / electrical device on the opposite side. The cells are connected to each other by a positive lead plate and a negative lead plate connecting the positive / cathode terminals of the protective circuit board and the positive / cathode terminals of the bare cell.

Secondary batteries are used in electronic / electrical devices by labeling the gap between the bare cell and the protective circuit board after resin molding or forming a battery pack having an external case while the bare cell and the protective circuit board are connected.

In the prior art, since the resin molding is performed while the anode / cathode lead plates connecting the bare cell and the protection circuit board are exposed, problems such as bending and twisting caused by external pressure are easily caused. It was.

In addition, the structure is complicated by forming a separate structure for maintaining and supporting the gap between the bare cell and the protective circuit board, and spot welding for connecting the anode / cathode lead plate with the bare cell and the anode / cathode terminal of the protective circuit board. There was discomfort in the poem.

The present invention provides a protective circuit board connected to a bare cell and including an electrical element for protecting the bare cell during overcharge, overdischarge, and overcurrent, wherein the protective circuit board includes a lead plate having a coupling groove. It is done.

The present invention is characterized in that it comprises a bare cell, a protective circuit board provided on one side of the bare cell, and the bare cell and the protective circuit board, one or more lead plates having a coupling groove.

The lead plate of the present invention is characterized in that the '⊂' shape or '⊃' shape.

The lead plate of the present invention is characterized in that the first lead plate provided in the bare cell and the second lead plate provided in the protective circuit board.

Each of the first lead plate and the second lead plate of the present invention is characterized in that the areas of two transverse cross sections are formed differently or identically.

Therefore, by changing the structure of the lead plate connecting the bare cell and the protection circuit board, it is possible to improve the reliability of bending and twisting caused by external pressure and to simplify the pack structure. Coupling of the cell and the protective circuit board can be facilitated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The details of the object and technical construction of the present invention and the resulting effects thereof will be more clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

1 is an exploded perspective view illustrating a bare cell provided in a battery pack according to a first embodiment of the present invention.

Referring to FIG. 1, the bare cell according to the first exemplary embodiment of the present invention accommodates an electrode assembly 100 and an electrolyte allowing lithium ions to move between the electrode assembly 100 and a can having an upper end opened. And a cap assembly 300 that seals the can 200 and is electrically connected to the electrode assembly 100.

The electrode assembly 100 is interposed between a positive electrode plate 120 formed by applying a positive electrode active material to a positive electrode current collector, a negative electrode plate 110 formed by applying a negative electrode active material to a negative electrode current collector, and two electrode plates 110 and 120. It includes a separator 130 to prevent the short circuit of the two pole plates (110, 120) and the movement of ions, a positive electrode tab 150 is connected to the positive electrode plate 120, the negative electrode tab 140 to the negative electrode plate 110 ) Is connected.

In FIG. 1, both the positive electrode tab 150 and the negative electrode tab 140 protrude to the top of the can. However, either of the positive electrode tab 150 or the negative electrode tab 140 moves to the lower side of the can 200. The protrusion may be electrically connected to the can 200.

The positive electrode plate 120 includes a positive electrode current collector and a positive electrode active material applied to the positive electrode current collector. The positive electrode active material may be formed of a layered compound containing lithium, a binder to improve bonding strength, and a conductive material to improve conductivity. As the positive electrode current collector, aluminum is generally used, and the positive electrode current collector serves as a movement path of charge generated in the positive electrode active material and serves to support the positive electrode active material.

A positive electrode non-coating portion (not shown) is formed on one side end of the positive electrode plate 120, and the positive electrode tab 150 is bonded to the positive electrode non-coating portion (not shown).

The negative electrode plate 110 includes a negative electrode current collector and a negative electrode active material applied to the negative electrode current collector. The negative electrode active material may include hard carbon, graphite, or the like containing carbon, and may include a binder to improve the bonding force between the negative electrode active materials. Copper is generally used as the negative electrode current collector, and serves as a movement path of charge generated in the negative electrode active material and supports the negative electrode active material.

A negative electrode non-coating portion (not shown) is formed on one side end of the negative electrode plate 110, and the negative electrode tab 140 is bonded to the negative electrode non-coating portion (not shown).

The separator 130 is interposed between the positive electrode plate 120 and the negative electrode plate 110 to insulate the two plates 110 and 120 and to allow the movement of lithium ions.

In general, the separator 130 may be formed of a polyolefin-based polymer film such as polyethylene (PE), polypropylene (PP), or a multilayer thereof, but the material is not limited thereto.

The can 200 may be formed of a metal material having an upper end opening. The can 200 accommodates an electrolyte solution together with the electrode assembly 100 and accommodates an insulation case inside the opening. As the metal material, the can 200 may serve as a terminal by being formed of a material such as light and ductile aluminum, aluminum alloy, or stainless steel.

The shape of the can 200 may be rectangular or oval with rounded corners, and the opening of the can 200 is sealed by welding or heat fusion with the cap plate. In this case, an insulating case for insulating the positive electrode tab 150 and the negative electrode tab 140 while protruding to the outside is mounted inside the can 200.

The cap assembly 300 coupled to the opened upper portion of the can 200 includes a cap plate 350, an insulation plate 340, a terminal plate 330, an insulation case 320, and an electrode terminal 310. .

The cap plate 350 is a metal plate having a size and a shape corresponding to the top opening of the can 200, and includes a terminal through hole 352 of a predetermined size, an electrolyte injection hole 354, and a safety vent (not shown). . The safety vent (not shown) may be formed in any area as long as it does not interfere with the terminal through hole 352 and the electrolyte injection hole 354, and may be formed on one side of the can 200.

The electrolyte injection hole 354 is for injecting an electrolyte solution for smooth movement of lithium ions into the can 200 containing the electrode assembly 100, and the can 200 is capped to the cap assembly 300. After the sealing is performed, the electrolyte is injected through the electrolyte injection hole 354, and the can 200 is sealed by sealing the electrolyte injection hole 354 with the electrolyte injection hole stopper 370.

The terminal through hole 352 is to insert the electrode terminal 310, the electrode terminal 310 and the terminal plate 330 is located below the cap plate 350 through the terminal through hole 352 and In order to electrically connect the electrode terminal 310 and the cap plate 350, a gasket 360 formed of a rubber or non-conductive material having good insulation is disposed outside the electrode terminal 310.

The insulating plate 340 and the terminal plate 330 are sequentially positioned on the lower surface of the cap plate 350, and the terminal plate 330 is electrically connected to the negative electrode tab 140 of the electrode assembly 100. The electrode terminal 310 and the negative electrode tab 140 are electrically connected to each other, and the insulating plate 340 electrically insulates the terminal plate 330 from the cap plate 350, thereby preventing the cap. Even if the plate 350 is electrically connected to the positive electrode tab 150 of the electrode assembly 100, a short circuit is prevented.

The insulating case 320 is positioned above the opening of the can 200 to fix the positive electrode tab 150 and the negative electrode tab 140 of the electrode assembly 100. The polypropylene (PP) and polyphenyl It may be formed of an insulating polymer resin such as lensulfite (PPS), polyether sulfone (PES), or modified polyphenylene oxide (PPO), and for mounting the terminal plate 330 and the insulating plate 340. In order to provide space, a support may be formed at the edge of the insulating case 320.

Figure 2a is an exploded perspective view of a battery pack according to a first embodiment of the present invention, Figure 2b is a perspective view of a protective circuit board provided in the first embodiment of the present invention, Figure 2c is a first embodiment of the present invention FIG. 2D is a view illustrating a bare cell and a protection circuit board coupling method, and FIG. 2D illustrates a coupled state of a first lead plate and a second lead plate according to the first embodiment of the present invention.

2A to 2D, a battery pack includes a bare cell 500 formed with an electrode assembly and a cap assembly in a can, a protective circuit board 600 provided above the bare cell 500, and the bare cell. It is composed of a plurality of lead plates (510, 710, 730) for electrically connecting the 500 and the protective circuit board 600.

The bare cell 500 includes an electrode terminal 310 and one or more first lead plates 510 insulated from the cap plate 350 by an insulating gasket 360.

The first lead plate 510 is formed in a '⊂' shape or a '⊃' shape having a coupling groove in the center, and the cross-sectional areas are different from each other, so that the cross-section having a large area is joined to the bare cell 500. And a transverse cross section having a small area faces upward, and a coupling groove faces inward. The coupling groove may be provided to face the outside.

As in this embodiment, two first lead plates 510 are provided at the edge of the bare cell 500 so that at least one first lead plate is used as an electrode lead plate for electrically connecting with the protection circuit board. Another first lead plate which is not used as an electrode lead plate is preferably used as an auxiliary lead plate that maintains a gap between the bare cell 500 and the protective circuit board 600. Both first lead plates 510 may be used as electrode lead plates.

For example, one first lead plate 510 may be connected to the electrode terminal 310, and the other first lead plate 510 may be connected to a terminal having a different polarity than that of the electrode terminal 310. It is also possible to use the first lead plate as an electrode lead plate having different polarities.

In addition, the structure of the present embodiment will be described below, but the second lead plate provided on the protective circuit board can be fastened in a sliding manner when the bare cell and the protective circuit board are coupled, thereby making it very easy to fasten. .

Of course, the number, location and use of the first lead plate is not limited to this embodiment, and various changes and modifications are possible by those skilled in the art.

The protection circuit board 600 includes a connection terminal for connecting an electrical element, a second lead plate 710, and an internal lead plate 730 on one surface of a printed circuit board 610 on which a wiring pattern is formed. On the opposite side, an external connection terminal 630 for connecting with an external electronic / electrical device is provided.

In addition, the protection circuit board 600 includes a groove 650 at a position corresponding to the first lead plate 510 and the electrode terminal 310 provided in the bare cell 500 to protect the bare cell 500. When spot welding is performed to connect the circuit board 600, it serves to provide a passage for welding and may be large enough to be welded.

The lead plate connected to the connection terminal of the protection circuit board 630 is connected to the electrode terminal 310 of the bare cell 500 and the first lead plate 510 of the bare cell 500. And a second lead plate 710 connected correspondingly with each other).

The inner lead plate 730 is a flat plate formed of nickel, and is connected to the electrode terminal 310 at the lower side and the connection terminal of the protective circuit board 600 at the upper side to form an electrical passage.

The second lead plate 710 is formed in a '⊂' shape or a '⊃' shape having a coupling groove in the center thereof, and the cross-sectional area of the second lead plate 710 is different from each other, so that the cross-section having a small area has a protective circuit board 600. It is provided so that the horizontal cross section which has a large area may be joined downward, and the coupling groove may face inward or outward, and it is joined with the connecting terminal of.

In this case, when connecting the bare cell 500 and the protection circuit board 600, the second lead plate 710 should have a lead plate having a different shape from that of the corresponding first plate 710.

That is, the first lead plate 510 of the '⊂' shape and the second lead plate 710 of the '⊃' shape correspond to each other, and the first lead plate 510 and the '⊂' shape of the '⊃' shape. The second lead plate 710 should be provided to correspond to each other.

In other words, when the first lead plate 510 is provided with the coupling groove facing inward, the corresponding second lead plate 710 should be provided with the coupling groove facing outward, and the first lead plate 510 is provided. When the coupling groove is provided to face the outside, the corresponding second lead plate 710 should be provided so that the coupling groove faces inward.

When the bare cell 500 and the protection circuit board 600 are connected according to the present invention, the protection circuit board (not a form of coupling the bare cell 500 and the protection circuit board 600 provided in the conventional upper and lower sides), The slide method 600 is coupled to the side of the bare cell 500.

At this time, a horizontal cross section having a large area of the second lead plate 710 provided in the protection circuit board 600 is coupled to the coupling groove of the first lead plate 510 of the bare cell 500, and the protection circuit board is coupled. The protective circuit board 600 of the protection circuit board 600 is coupled with a horizontal cross section having a small area of the first lead plate 510 provided in the bare cell 500 to the coupling groove of the second lead plate 710 provided in the 600. Join by welding through the groove (650).

In FIG. 2D, although the first lead plate 510 and the second lead plate 710 of the present invention have the same shape and are combined in different directions, the first lead plate 510 and the second lead plate 710 are different from each other. Different shape of the second lead plate 710 may be combined.

For example, the first lead plate 510 is formed to have two areas of the horizontal cross sections 510a and 510b, and the second lead plate is provided at the lower end of the two cross sections 710a provided at the upper side. Smaller than the end face 710b may be combined.

Of course, after the first lead plate 510 and the second lead plate 710 are combined, a structure capable of welding the upper surface 510a of the first lead plate 510 or the upper surface 710a of the second lead plate 710. Should be

The bare cell 500 and the protection circuit board 600 combined as described above may be stored in a separate outer case or filled with a gap with a hot-melt resin, and the battery pack may be thinned by tubing or labeling. Is achieved.

3A is an exploded perspective view of a battery pack according to a second embodiment of the present invention, and FIG. 3B is a view illustrating a method of coupling a bare cell and a protection circuit board according to a second embodiment of the present invention.

3A and 3B, the bare cell 500 ′ constituting the battery pack is similar to the bare cell 500 of the first embodiment. The electrode terminal 310 'insulated by 360' protrudes to the outside.

The protective circuit board 600 ′ is provided with an external connection terminal 630 ′ for connecting an electronic / electrical device to one surface of a printed circuit board 610 ′ in which a wiring pattern is formed. It is connected to the outer lead plate, and the inner lead plate (810, 820).

The protective circuit board 600 ′ may have a structure in which the protective circuit board 600 is connected while the internal lead plate 820 is provided at the electrode terminal 310 ′ of the bare cell 500 ′. In the structure in which the 820 is provided on the protective circuit board 600 and connected to the bare cell 500 ', the protective circuit board corresponding to the point where the inner lead plate 820 and the electrode terminal 310' are joined ( 600 ') may be provided with a groove 650' for providing a weldable passage during spot welding.

Unlike the first embodiment in which the external lead plate 810 includes a first lead plate 510 and a second lead plate 710 connected to the bare cell 500 and the protection circuit board 600, respectively, The first lead plate 510 and the second lead plate 710 are coupled to each other, and are provided in the bare cell 500 'before the bare cell 500' and the protection circuit board 600 'are connected.

In the second embodiment, unlike the first embodiment in which the protective circuit board 600 is slidably coupled to the side of the bare cell 500, the protective circuit board 600 ′ is formed at the upper side of the bare cell 500 ′. It is preferable to use for the structure to couple | bond.

The bare cell 500 'and the protection circuit board 600' combined as described above may be stored in a separate outer case or filled with a gap with a hot-melt resin, and the battery may be thinned with tubing and labeling. Packed.

The present invention shows a preferred embodiment as described above, but is not limited to the above-described embodiment and various modifications by those skilled in the art without departing from the spirit of the present invention Modifications and variations are possible.

1 is an exploded perspective view illustrating a bare cell provided in a battery pack according to a first embodiment of the present invention.

2A is an exploded perspective view of a battery pack according to a first embodiment of the present invention.

2B is a perspective view showing the structure of a protective circuit board provided in the first embodiment of the present invention.

2C is a diagram illustrating a method of coupling a bare cell and a protection circuit board according to a first embodiment of the present invention.

Figure 2d is a view showing a combined state of the first lead plate and the second lead plate of the present invention.

3A is an exploded perspective view of a battery pack according to a second embodiment of the present invention.

3B is a view showing a method of coupling a bare cell and a protection circuit board according to a second embodiment of the present invention.

[Description of Major Reference Code]

100 electrode assembly 110 negative electrode plate

120: positive electrode plate 130: separator

140: negative electrode tab 150: positive electrode tab

200: can 300: cap assembly

310, 310´: electrode terminal 320: insulated case

330: terminal plate 340: insulation plate

350: cap plate 352: terminal through

354: electrolyte injection hole 360, 360´: insulating gasket

370: electrolyte injection hole cap 500, 500 ': bare cell

510: first lead plate 600, 600 ': protective circuit board

610, 610´: Printed circuit board 630, 630´: External connection terminal

650, 650´: Groove 710: Second lead plate

730, 820: inner lead plate 810: outer lead plate

Claims (12)

A protective circuit board connected to a bare cell and having an electrical element for protecting the bare cell during overcharge, overdischarge, and overcurrent, The protective circuit board comprises a lead plate having a coupling groove. The method of claim 1, The lead plate is a protective circuit board, characterized in that the '⊂' shape or '⊃' shape. The method of claim 2, The lead plate is a protective circuit board, characterized in that the area of the two transverse cross-section is formed differently or the same. The method of claim 1, The protective circuit board has a protective circuit board, characterized in that provided with a groove corresponding to the position where the lead plate is provided. The method of claim 4, wherein The groove is a protective circuit board, characterized in that provided to expose a portion of the lead plate. Bare cells; A protection circuit board provided at one side of the bare cell; And And one or a plurality of lead plates connecting the bare cell and the protective circuit board and having coupling grooves. The method of claim 6, The lead plate is formed of nickel, characterized in that the battery pack. The method of claim 6, The lead plate is a battery pack, characterized in that the first lead plate provided in the bare cell and the second lead plate provided in the protective circuit board. The method of claim 8, The first lead plate and the second lead plate is a battery pack, characterized in that the '⊂' shape or '⊃' shape. The method of claim 9, The first lead plate and the second lead plate each of the battery pack, characterized in that the area of the two transverse cross-section is formed differently or the same. The method of claim 10, When the bare cell and the protection circuit board are connected to the first lead plate and the second lead plate, if the first lead plate has a '⊂' shape, the second lead plate has a '⊃' shape and the first lead If the plate is a '⊃' shape, the second lead plate is a '⊂' shape battery pack, characterized in that. The method of claim 11, When the bare cell and the protective circuit board are connected to the first lead plate and the second lead plate, one surface of the first lead plate is provided in a coupling groove of the second lead plate, and the second lead plate One side of the battery pack, characterized in that provided in the coupling groove of the first lead plate.

Images