JP3738202B2 - Pack battery and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery pack and a method for manufacturing the battery pack, and more particularly to a battery pack and a method for manufacturing the battery pack in which the battery and a printed board are connected by a lead plate.
[0002]
[Prior art]
The battery pack has a battery and a printed circuit board built in an outer case. The printed circuit board fixes electronic components that realize output terminals and protection circuits. The printed circuit board is connected to the battery via a lead plate. The printed circuit board has a conductive plate fixed to connect the lead plate. The conductive plate is soldered and fixed to the printed circuit board, or is printed on the printed circuit board. The conductive plate and the lead plate can be connected by soldering or spot welding. Spot welding has the advantage that the lead plate can be connected to the conductive plate in a simple and secure manner.
[0003]
[Problems to be solved by the invention]
However, if the lead plate is spot welded to the printed circuit board and connected, spot dust and solder balls may be scattered around when spot welding is performed. Spot dust or the like that scatters to the periphery adheres to electronic parts and has an adverse effect, or causes adhesion to the conductive part and a short circuit. For this reason, spot dust and solder balls have the adverse effect of lowering the yield in the manufacturing process of the battery pack or increasing the failure rate and lowering the reliability of the battery pack. In order to eliminate this adverse effect, the conventional battery pack is actually spot spot and solder ball removed after spot welding of the lead plate. However, it is extremely difficult and time-consuming to completely remove spot dust and solder balls. This is because it adheres firmly to a printed circuit board and electronic parts and cannot be removed if it enters a very narrow gap or the like. A battery pack in which spot dust and solder balls have not been completely removed has a high failure rate and decreases reliability.
[0004]
The harmful effect of spot dust and solder ball scattering can be prevented by providing a protective wall around the conductive plate. However, in the actual manufacturing process of a battery pack, it is extremely difficult to provide a protective wall around the conductive plate. This is because in all battery packs, there is no space for providing a protective wall around the conductive plate. Therefore, the scattered spot dust and solder balls have to be removed after spot welding, and this processing is troublesome.
[0005]
The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide a battery pack capable of significantly improving reliability by minimizing the adverse effects of spot dust and solder balls generated when spot welding a lead plate to a printed circuit board without providing a dedicated member. It is in providing the manufacturing method.
[0006]
[Means for Solving the Problems]
The battery pack of the present invention includes a printed circuit board 5 to which a conductive plate 6 is fixed, a substrate holder 4 that is disposed on the conductive plate 6 side of the printed circuit board 5 and holds the printed circuit board 5 in a fixed position, and a printed circuit board. And a battery 3 connected to the printed circuit board 5 via a lead plate 7 connected to the conductive plate 6 by spot welding. The substrate holder 4 has a scattering prevention enclosure 13 surrounding the conductive plate 6 provided on the printed circuit board 5. The substrate holder 4 is provided with a through portion 13A on the inner side surrounded by the scattering prevention enclosure 13, and the lead wire is spot welded to the conductive plate 6 through the through portion 13A.
[0007]
The substrate holder 4 can be shaped to cover a portion other than the conductive plate 6 of the printed circuit board 5.
[0008]
The battery pack of the present invention preferably stores the printed circuit board 5, the substrate holder 4, and the battery 3 in the outer case 1. The battery 3 can be a thin prismatic battery. This battery pack stores the printed circuit board 5 and the substrate holder 4 between the rectangular battery sealing plate 3B and the outer case 1, and stores the printed circuit board 5 in a posture orthogonal to the rectangular battery sealing plate 3B. . Furthermore, the battery pack of the present invention can connect the PTC element 15 to the lead plate 7 spot welded to the conductive plate 6 of the printed circuit board 5.
[0009]
In the method for manufacturing a battery pack according to the present invention, a lead plate 7 is spot welded to a conductive plate 6 fixed to the printed circuit board 5, and the printed circuit board 5 is connected to the battery 3 with the lead plate 7. The substrate holder 4 is set on the surface of the printed circuit board 5 on which the conductive plate 6 is provided. The substrate holder 4 has a scattering prevention enclosure 13 surrounding the conductive plate 6, and a through portion 13 </ b> A is provided inside the scattering prevention enclosure 13. In a state in which the conductive plate 6 provided on the printed circuit board 5 is surrounded by the scattering prevention enclosure 13 of the substrate holder 4, the lead plate 7 is spot welded to the conductive plate 6 at the through portion 13 </ b> A, and the lead plate 7 is attached to the conductive plate 6. Link.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify the battery pack and its manufacturing method for embodying the technical idea of the present invention, and the present invention does not specify the battery pack and its manufacturing method as follows. .
[0011]
Further, in this specification, in order to facilitate understanding of the scope of claims, the numbers corresponding to the members shown in the examples are referred to as “the scope of claims” and “the means for solving the problems”. It is added to the member shown by. However, the members shown in the claims are not limited to the members in the embodiments.
[0012]
The battery pack shown in FIGS. 1 and 2 has a battery assembly 2 in an outer case 1 as shown in FIGS. The outer case 1 includes a plastic upper case 1A and a lower case 1B. The upper case 1A and the lower case 1B are rectangles of the same size, and the peripheral wall is integrally formed along the periphery. The upper case 1A and the lower case 1B connect the peripheral walls to each other and house the battery assembly 2 therein. The exterior case 1 has an electrode window 10 opened in the lower case 1B. The electrode window 10 exposes the output terminal fixed to the battery assembly 2 to the outside. Therefore, the electrode window 10 is disposed at the position of the output terminal. An output terminal exposed to the outside from the electrode window 10 is connected to a power supply terminal of an electric device in which the battery pack is mounted.
[0013]
As shown in the exploded perspective views of FIGS. 4 and 5, the battery assembly 2 has a printed circuit board 5 connected to the battery 3 via a lead plate 7. The battery 3 is a thin prismatic battery. A prismatic battery is a lithium ion secondary battery. This battery pack has a feature that the charge capacity with respect to the volume can be increased. However, in the battery pack of the present invention, the battery 3 is not specified as a square battery, and a cylindrical battery can also be used. A plurality of batteries can also be stored in the outer case. Furthermore, a secondary battery such as a nickel-hydrogen battery or a nickel-cadmium battery can be used as the battery instead of the lithium ion secondary battery.
[0014]
The outer case 1 has a storage space 8 for storing the printed circuit board 5 and the substrate holder 4 in a state in which the battery 3 is stored. In other words, the printed circuit board 5 and the substrate holder 4 are stored in a state of being fitted in the storage space 8. The battery assembly 2 is integrated by connecting a printed board 5 and a board holder 4 to the battery 3. Accordingly, the outer shape of the battery assembly 2 is substantially equal to the inner shape of the outer case 1, and the battery assembly 2 is stored in the outer case 1 without moving rattlingly.
[0015]
The printed circuit board 5 is connected to the battery 3 so as to be in a posture perpendicular to the sealing plate 3B of the battery 3. Furthermore, the printed circuit board 5 is disposed close to the inner surface of the lower case 1B in FIG. This is because the output terminal 9 fixed to the lower surface is exposed to the outside from the electrode window 10 of the lower case 1B. In the figure, a gap is formed on the upper surface of the printed circuit board 5. A substrate holder 4 is disposed in the gap, and the printed circuit board 5 is held at a fixed position by the substrate holder 4. The printed circuit board 5 has a conductive plate 6 fixed to a surface facing the substrate holder 4.
[0016]
4 and 5, the printed board 5 is connected to the battery 3 by two lead plates 7, and the board holder 4 is disposed on the conductive plate 6 side of the printed board 5. The printed circuit board 5 has a conductive plate 6 fixed to the upper surface in the drawing in order to connect the lead plate 7 by spot welding. The conductive plate 6 is a nickel plate or a nickel-plated metal plate, and is fixed to the printed circuit board 5 by soldering. However, the conductive plate can be fixed by printing a metal thin film on a printed circuit board. The printed circuit board 5 shown in the figure is rectangular and is cut to a length substantially equal to the length of the outer can 3A of the battery 3. The printed circuit board 5 that fixes the + -output terminal 9 needs to be connected to the positive and negative electrodes of the battery 3. The printed board 5 shown in the figure has two conductive plates 6 fixed to both end portions. The printed circuit board 5 connected to the positive and negative electrodes of the battery 3 needs to fix at least two, that is, a plurality of conductive plates 6, and each conductive plate 6 needs to be connected to the battery 3 by the lead plate 7.
[0017]
Furthermore, although not shown, the printed circuit board 5 also fixes electronic components that realize a battery protection circuit. These electronic components are fixed to the side on which the conductive plate 6 is fixed, that is, the surface facing the substrate holder 4, that is, the upper surface in FIG. The printed circuit board 5 has an output terminal 9 fixed to the lower surface in FIG. The output terminal 9 is a nickel plate or nickel-plated metal plate like the conductive plate 6 and is fixed to the printed circuit board 5 by soldering.
[0018]
The substrate holder 4 is integrally formed of plastic as a whole. The substrate holder 4 is formed to a size that fits into a gap surrounded by the printed circuit board 5, the upper case 1 </ b> A inner surface, and the battery 3. The substrate holder 4 has two functions. The first function is to hold the printed circuit board 5 in a fixed position. The substrate holder 4 shown in FIG. 3 and FIG. 4 prevents the position and posture of the printed circuit board 5 from shifting, and holds the printed circuit board 5 in a position determined at a fixed position. Further, the substrate holder 4 shown in FIGS. 3 and 4 is provided with a positioning protrusion 11 that protrudes toward the printed circuit board 5, that is, the lower surface in the drawing. The positioning protrusion 11 is fitted into a positioning recess 12 provided in the printed circuit board 5 and prevents the printed circuit board 5 from moving along the surface of the substrate holder 4. The substrate holder 4 has a feature that it can hold the printed circuit board 5 without being particularly displaced. However, it is not always necessary to provide the positioning protrusion on the substrate holder. This is because the printed circuit board 5 connected to the battery 3 by the lead plate 7 can be fitted in a fixed position so as not to move between the battery 3, the printed circuit board 5, and the inner surface of the upper case 1A. The lead plate 7 prevents positional displacement in the plane including the surface of the printed circuit board 5 indicated by arrows A and B in FIGS. 3 and 4, but prevents posture change in the direction in which the lead plate 7 is bent. Is difficult. The substrate holder 4 can prevent the posture change in the direction in which the lead plate 7 is bent. Further, the board holder 4 is fitted into the gap on the inner surface of the upper case 1A, and the positional deviation of the printed board 5 in the directions of arrows A and B is reduced.
[0019]
The second function of the substrate holder 4 is to prevent spot dust and solder balls from scattering. When the lead plate 7 is spot welded to the conductive plate 6 of the printed circuit board 5, spot dust and solder balls are scattered around. The substrate holder 4 effectively prevents this scattering and prevents a failure caused by this. In order to realize this function, the substrate holder 4 has a scattering prevention enclosure 13 surrounding the conductive plate 6 provided on the printed circuit board 5. As shown in FIGS. 4 to 7, the substrate holder 4 is provided with a penetrating portion 13 </ b> A that penetrates the inside of the scattering prevention enclosure 13 on both sides. A lead electrode 7 is spot welded to the conductive plate 6 by inserting a welding electrode into the through portion 13A. Further, the substrate holder 4 shown in the above figures covers a portion of the printed board 5 other than the conductive plate 6 with a cover portion 4A. The substrate holder 4 with the cover portion 4A has an advantage that it can prevent spot dust and solder balls from adhering to the printed circuit board 5 in an ideal state. This is because the cover portion 4 </ b> A covers portions other than the conductive plate 6. However, since the battery pack of the present invention can prevent spot dust and solder balls from being scattered by the scattering prevention enclosure surrounding the conductive plate, it is not always necessary to cover the portion other than the conductive plate with the cover portion.
[0020]
The substrate holder 4 shown in the drawing is formed into a shape in which two opposing plates 4B are connected in parallel by a cover portion 4A and both ends of the opposing plate 4B are connected by end plates 4C. In the substrate holder 4, the width of the counter plate 4 </ b> B is substantially equal to the thickness of the battery 3. The opposing plate 4B facing the sealing plate 3B of the battery 3 is provided with an insertion recess 14 into which the projection electrode 3C is inserted. The projection electrode 3 </ b> C of the battery 3 is inserted into the insertion recess 14, and the substrate holder 4 is connected to a fixed position of the battery 3. Further, the two opposing plates 4B are located on both sides of the printed circuit board 5, and a through portion 13A is formed between both ends of the cover portion 4A and the end plate 4C. In the substrate holder 4, the scattering prevention enclosure 13 is composed of two opposing plates 4B, a cover portion 4A, and an end plate 4C.
[0021]
The battery pack having the above structure is assembled as follows.
(1) One end of the lead plate 7 is connected to the positive and negative electrodes of the battery 3 by spot welding. One lead plate 7 connects the PTC elements 15.
(2) The other end of the lead plate 7 is brought into contact with the conductive plate 6 of the printed board 5, and the board holder 4 is overlaid on the printed board 5 in this state. The substrate holder 4 is connected to a fixed position of the printed circuit board 5 by inserting the positioning protrusion 11 into the positioning recess 12 of the printed circuit board 5. In this state, the substrate holder 4 surrounds the periphery of the conductive plate 6 with the anti-scattering enclosure 13, and the conductive plate 6 is located in the through portion 13 </ b> A of the substrate holder 4.
(3) A welding electrode is inserted into the through portion 13A of the substrate holder 4. This welding electrode presses the lead plate 7 against the conductive plate 6 at the tip. The welding electrode applies a large current to the lead plate 7 and the conductive plate 6 to spot weld the lead plate 7 to the conductive plate 6. In this process, the battery assembly 2 is completed.
(4) The battery assembly 2 is placed in the lower case 1B. In this state, the output terminal 9 fixed to the printed circuit board 5 is positioned in the electrode window 10 of the lower case 1B. The upper case 1A is connected to the lower case 1B, and the outer case 1 is closed. The upper case 1A and the lower case 1B are connected by welding or bonding their peripheral walls, or are connected by screwing the upper case and the lower case.
[0022]
【The invention's effect】
The battery pack and manufacturing method of the present invention can significantly improve the reliability by reducing the adverse effects caused by spot dust and solder balls generated when spot welding a lead plate to a printed circuit board without providing a dedicated member. There are features. The battery pack of the present invention and the method of manufacturing the battery pack are provided with a substrate holder on the conductive plate side of the printed circuit board to which the conductive plate is fixed, and the substrate holder is provided with a shatterproof enclosure surrounding the conductive plate. This is because spot welding is performed at a through portion inside the anti-scattering enclosure so that the conductive plate provided on the printed circuit board is surrounded by the anti-scattering enclosure of the substrate holder. The battery pack of the present invention and the manufacturing method thereof effectively prevent spot dust and solder balls from being scattered by the scattering prevention enclosure provided on the substrate holder. Can be manufactured efficiently. In addition, since the failure caused by spot dust or solder ball scattering can be effectively prevented, the reliability of the product can be increased. In particular, according to the present invention, the board holder for holding the printed circuit board in a fixed position is provided with an anti-scattering enclosure and is used together with an anti-scattering member for spot dust and solder balls, so that it can be arranged in a small space and the number of parts can be reduced. Manufacturing costs can be reduced.
[Brief description of the drawings]
1 is a perspective view of a battery pack according to an embodiment of the present invention. FIG. 2 is a perspective view of a battery pack according to another embodiment of the present invention. FIG. 3 is an exploded perspective view of the battery pack shown in FIG. 4 is an exploded perspective view of the battery pack shown in FIG. 2. FIG. 5 is an exploded perspective view of the battery assembly shown in FIG. 3. FIG. 6 is a cross-sectional view of the battery pack shown in FIG. Magnified perspective view
DESCRIPTION OF SYMBOLS 1 ... Outer case 1A ... Upper case 1B ... Lower case 2 ... Battery assembly 3 ... Battery 3A ... Outer can 3B ... Sealing plate 3C ... Convex electrode 4 ... Substrate holder 4A ... Cover part 4B ... Opposite plate 4C ... End plate 5 ... Printed circuit board 6 ... Conductive plate 7 ... Lead plate 8 ... Storage space 9 ... Output terminal 10 ... Electrode window 11 ... Positioning convex part 12 ... Positioning concave part 13 ... Scattering prevention enclosure 13A ... Penetration part 14 ... Insertion concave part 15 ... PTC element

Claims (5)

A printed circuit board (5) fixing the conductive plate (6) and a substrate holder (4) disposed on the conductive plate (6) side of the printed circuit board (5) to hold the printed circuit board (5) in place. And a battery (3) connected to the printed circuit board (5) via a lead plate (7) connected by spot welding to the conductive plate (6) of the printed circuit board (5),
The substrate holder (4) has a shatterproof enclosure (13) surrounding the conductive plate (6) provided on the printed circuit board (5), and the through portion (13A) is surrounded by the shatterproof enclosure (13). A battery pack in which the lead plate (7) is spot welded to the conductive plate (6) through the through-hole (13A). The battery pack according to claim 1, wherein the substrate holder (4) has a shape covering a portion other than the conductive plate (6) of the printed circuit board (5). The printed board (5), board holder (4) and battery (3) are housed in the outer case (1) .The battery (3) is a thin square battery, and the square battery sealing plate (3B) and The printed circuit board (5) and the substrate holder (4) are stored between the outer case (1) and the printed circuit board (5) is stored in a posture orthogonal to the sealing plate (3B) of the rectangular battery. Item 4. A battery pack according to item 1. The battery pack according to claim 1, wherein the PTC element (15) is connected to a lead plate (7) spot welded to the conductive plate (6) of the printed circuit board (5). Manufacture of a pack battery in which the lead plate (7) is spot welded to the conductive plate (6) fixed to the printed circuit board (5), and the printed circuit board (5) is connected to the battery (3) with the lead plate (7). In the method
On the surface of the printed circuit board (5) where the conductive plate (6) is provided, there is a shatterproof enclosure (13) surrounding the conductive plate (6), and the penetration part (13A) is inside this shatterproof enclosure (13). Set the board holder (4) provided with a through-hole (13A) so that the conductive plate (6) provided on the printed circuit board (5) is surrounded by the scattering prevention enclosure (13) of the board holder (4). ) Spot welding the lead plate (7) to the conductive plate (6) and connecting the lead plate (7) to the conductive plate (6).

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