JP2007200630A - Battery pack, its assembling method, and portable electronic appliance using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily connect a battery cell and a protective circuit board, and to reduce the number of parts and make an assembly work easy, for a battery pack used for a portable electronic apparatus. <P>SOLUTION: In the battery pack packing a battery cell 1 and the protective circuit board 2 with an upper case 10 and a lower case 11, as a method for keeping the protective circuit board 2 adhered to a side face of the case and electrically connecting the battery cell 1 and the protective circuit board 2, an anode 3 and a cathode 4 of the battery cell 1 is press-fit into conductive connecting parts 5, 6 of a material excellent in alkali resistance and with small electric resistance provided on the protective circuit 2, instead of spot welding lead plates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery pack, a method for assembling the battery pack, and a portable electronic device using the same, and more particularly to a battery pack in which battery cells and a circuit board are housed in a battery case, a method for assembling the battery pack, and a portable electronic device using the battery pack. Is.

  In recent years, chargeable / dischargeable lithium ion secondary batteries and the like are used as main power sources in portable electronic devices such as digital cameras and mobile phones. A battery pack using a lithium ion secondary battery includes a circuit board (referred to as a protection circuit board) equipped with a protection circuit for preventing overcharge, overdischarge, overcurrent, and short circuit, a battery cell, an exterior case, It consists of

  4 and 5 are diagrams for explaining the configuration of a conventional battery pack. In FIG. 4, (A) is a side view of the battery pack as viewed from the terminal side, and (B) is B- of (A). Sectional drawing along line B, (C) is a sectional view along line CC in (A), and FIG. 5 shows an exploded perspective view excluding the case. The configuration of this conventional battery pack will be described.

  As shown in FIGS. 4 and 5, the conventional battery pack has a battery cell 1, a protection circuit board 2 on which an electrical component 8 is mounted, a negative electrode lead plate 5 ′, a positive electrode lead plate 6 ′, and an upper case 10. The lower case 11 is used.

  The battery cell 1 is an aluminum can, in which a positive electrode and a negative electrode are housed as a current collecting band via a separator. A convex battery negative electrode terminal 3 is formed in the battery cell 1, and all other portions serve as the battery positive electrode terminal 4. The convex battery negative electrode 3 is connected to the conductive plate 7 on the protective circuit board 2 via the negative electrode lead plate 5 ′, and the battery positive electrode 4 is connected to the positive electrode lead plate 6 ′ (as shown in FIG. The lead plate 6 'is connected to the conductive plate 9 on the protection circuit board 2 via a pair of L-shaped conductive lead plates 6d and 6e).

  And in the battery cell 1, the insulating paper 12 is affixed between the positive electrode 3 and the negative electrode lead board 5 'in order to prevent short circuit of both. On one surface of the protection circuit board 2, conductive plates 7 and 9 for connecting the negative electrode lead plate 5 ′ and the positive electrode lead plate 6 ′, and an electrical component 8 are mounted. On the opposite surface of the protection circuit board 2, a terminal 9 for connection with a portable device is provided.

  The battery pack is assembled with the battery cell 1 and the protection circuit board 2 in the lower case 11 and finally fixed with ultrasonic welding or heat welding in a state where the upper case 10 is covered to complete the rectangular battery pack. It will be.

  Next, a method for connecting the battery cell 1 and the protection circuit board 2 will be described. After the conductive plates 7 and 9 and the electrical component 8 are mounted on the protection circuit board 2, the conductive plate 7 and the negative electrode lead plate 5 ′ are spot welded to the conductive plate 9 and the positive electrode lead plate 6e, respectively. To do. Next, the positive electrode 4 and the positive electrode lead plate 6d of the battery cell 1 are spot-welded, and the negative electrode lead plate 5 ′ is bent into a crank shape (or U shape) with a jig, so that the negative electrode 3 and the spot of the battery cell 1 are spotted. Weld. Finally, the connection between the battery cell 1 and the protection circuit board 2 is completed by spot welding the positive electrode lead plate 6d and the positive electrode lead plate 6e.

  Patent Documents 1 and 2 are technologies related to the structure of the battery pack. In Patent Document 1, when the battery cell and the circuit board are connected, the tabs are returned to the positive and negative electrodes of the battery cell and the circuit board by welding. Moreover, in patent document 2, it is the structure of the cylindrical nickel-metal hydride battery for motor vehicles, and it pulls out a welding electrode stick | rod from a battery cell, and is performed by welding.

JP 2005-142153 A JP 2000-067833 A

  4 and 5, the battery cell 1 and the protection circuit board 2 are provided inside the battery pack. The battery cell 1 and the protection circuit board 2 are made of a conductive lead plate 5 made of nickel. Electrical connection is made by electrical resistance welding (spot welding) at “6, 6”, and such an assembling method has become mainstream in the past.

  Problems in the assembly structure of such a conventional battery pack include that the battery cell and the protection circuit board are nickel between the positive electrode of the battery cell and the protection circuit board and between the negative electrode of the battery cell and the protection circuit board, respectively. Since spot welding is performed using a manufactured conductive lead plate, there is a problem that spot dust, solder balls, or the like scatter and cause a short circuit. Furthermore, there is a problem that the lead plate is detached from the cell side or the protection circuit board due to variations in the welding strength of spot welding.

  If the spot-welded part is not completely rust-proofed, there is a problem that rust is generated from it. In addition, in order to perform spot welding, there is a conductive property on the protective circuit board and the positive and negative electrodes of the battery cells. A plate is required, and furthermore, insulation paper is necessary to prevent short-circuiting between the battery cell and the conductive lead plate, which increases the number of parts and the number of spot welding points, increasing the cost and mass. There is a disadvantage that there are many problems.

  Furthermore, since the conductive plate mounted on the battery cell and the protection circuit board needs to consider heat conduction and the like, it requires a relatively large area, and thus the battery pack can be downsized. It is also a hindrance.

  In the case of Patent Documents 1 and 2, there are disadvantages that the number of assembling steps and the number of parts are increased due to the connection by welding, and it does not contribute to downsizing.

  An object of the present invention is to provide a battery pack that can easily connect a battery cell and a protection circuit board, reduce the number of parts, and can be easily assembled, a method for assembling the battery pack, and a portable electronic device using the battery pack. To do.

  The battery pack according to the present invention is a battery pack in which a battery cell and a circuit board are accommodated in a battery case, and the battery pack and the circuit board are connected by press-fitting.

  A battery pack assembling method according to the present invention is a battery pack assembling method in which a battery cell and a circuit board are housed in a battery case, and the battery pack and the circuit board are connected when the battery pack is connected. The method includes the step of press-fitting the positive and negative electrode terminals of the pack into the connection parts of the circuit board.

  A portable electronic device according to the present invention uses the above battery pack.

  According to the present invention, the following effects can be obtained. The first effect is that the battery cell and the protection circuit board are spotted between the positive electrode of the battery cell and the protection circuit board and between the negative electrode of the battery cell and the protection circuit board with a nickel conductive lead plate, respectively. Since it becomes unnecessary to weld, and the rust prevention treatment of the spot-welded portion is not required, a highly reliable battery pack can be provided without spot dust, solder balls, or the like being scattered.

  The second effect is that, in the prior art, it was necessary to mount a conductive plate on the protective circuit board in order to perform spot welding. However, in the present invention, the conductive plate is unnecessary, and the battery cell and the protective circuit board are used. In this case, since the insulating paper for preventing short circuit of the nickel conductive lead plate is not required, the number of parts of the battery pack, the mass and the cost can be reduced.

  The third effect is that the conductive plate on the protection circuit board and the conductive lead plate for spot welding are not required, so that the conductive lead plate is not required to be routed, thereby reducing the size of the battery pack. It is possible to plan. The fourth effect is that in the battery pack assembling work, the protective circuit board is fixed along the side wall of the lower case, and the positive and negative electrodes of the battery cells are press-fitted into the plate of the protective circuit board. Is easy.

  Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are diagrams for explaining the present invention. 1, (A) is a side view of the battery pack as viewed from the terminal side, (B) is a cross-sectional view taken along line BB in (A), and (C) is taken along line CC in (A). FIG. 2 is a sectional view, and FIG. 2 shows an exploded perspective view excluding the case. 1 and 2, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals.

  As shown in FIG. 1, the battery pack includes a battery cell 1, a protection circuit board 2, an upper case 10, and a lower case 11. The battery cell 1 is an aluminum can, in which a positive electrode and a negative electrode are housed as a current collecting band via a separator. The battery cell 1 is formed with a negative electrode terminal 3 having a cylindrical protrusion 3a, and the other portions are all positive electrode terminals 4, but the positive electrode terminal 4 connected to the protection circuit board 2 is The cylindrical protrusion 4a is provided.

  The protective circuit board 2 is made of a conductive material having excellent alkali resistance and low electrical resistance for press-fitting and connecting the protrusion 3 a of the negative electrode terminal 3 and the protrusion 4 a of the positive electrode terminal 4 of the battery cell 1. An electrical component 8 having a negative electrode connection component 5 and a positive electrode connection component 6 and preventing overcharge, overdischarge, overcurrent, and short circuit is mounted. The protection circuit board 2 is provided in close contact with the side surface of the case.

  The negative electrode connection component 5 and the positive electrode connection component 6 are provided with insertion holes 50 and 60 for press-fitting the protrusion 3a of the negative electrode terminal 3 and the protrusion 4a of the positive electrode terminal 4 of the battery cell 1, respectively. These insertion holes 50 and 60 have a circular shape having a slightly smaller diameter than the protrusions 3 a and 4 a of the positive electrode terminal 3 and the negative electrode terminal 4 of the battery cell 1. On the opposite surface of the protection circuit board 2, a terminal 9 for connecting to a portable device is provided.

  The upper case 10 and the lower case 11 are ultrasonically welded using a molded resin. However, the battery cell 1 and the protective circuit board 2 can be wrapped with a label or the like to form a battery pack.

  Next, a method for connecting the battery cell 1 and the protection circuit board 2 will be described. After mounting the negative electrode connecting component 5, the positive electrode connecting component 6, and the electric component 8 on the protective circuit board 2, the protective circuit board 2 is mounted and fixed to the side surface of the lower case 11, and the negative electrode terminal 3 of the battery cell 1 is fixed. The battery cell 1 is assembled into the lower case 11 while the protrusion 3a and the protrusion 4a of the positive electrode terminal 4 are press-fitted into the negative electrode connecting component 5 and the positive electrode connecting component 6, respectively.

  By making the area of the negative electrode 3 of the battery cell 1 larger than that of the negative electrode connection terminal 5 so that the negative electrode connection terminal 5 does not short-circuit with the positive electrode of the battery cell 1 during this press-fitting, it is not necessary to attach insulating paper or the like. Finally, with the upper case 10 covered, it is fixed by ultrasonic welding, heat welding, or the like, thereby completing a rectangular battery pack.

  Next, another embodiment according to the present invention will be described. 3A to 3C are diagrams illustrating examples of the positive electrode connecting component and the negative electrode connecting component according to the present embodiment. Referring to FIG. 3A, the positive electrode connection component 6a and the negative electrode connection component 5a are equivalent to the structure shown in FIG. 2 in the previous embodiment, but can be elastically deformed using an elastic material. It is a thing.

  That is, the negative electrode connection 5a and the positive electrode connector portion 6a for connecting the battery cell 1 and the protection circuit board 2 are made of a conductive material having a spring property, and are easily press-fitted with the battery cell 1. The same effect as the previous embodiment can be obtained by using the one that can move to the left and right in consideration of the above. In this case, the protrusions 3a and 4a on the negative electrode terminal 3, the positive electrode terminal 4, and the holes 50 and 60 on the negative electrode connection components 5a and 6a may be omitted. Each of the negative electrode terminal 3 and the positive electrode terminal 4 and the negative electrode connection component may be omitted. Surface contact by pressure contact with each of 5a and 6a may be used.

  In FIG. 3 (B), the negative electrode connecting component 5b and the positive electrode connecting portion 6b are formed in an elastic Z-shape. Also in this case, the negative electrode terminal 3, the protrusions 3a and 4a in the positive electrode terminal 4, and the holes 50 and 60 in the negative electrode connection parts 5a and 6a are provided and press-fitted. Surface contact by pressure contact between each of the positive electrode terminals 4 and each of the negative electrode connecting parts 5a and 6a may be used.

  Further, the same effect can be obtained by press-fitting and caulking a part having a coil type spring property such as the negative electrode connecting part 5c and the positive electrode connecting part 6c. In this example as well, the protrusions 3a and 4a on the negative electrode terminal 3 and the positive electrode terminal 4 may not be provided, and the tips of the coil springs may be pressed against each surface of the negative electrode terminal 3 and the positive electrode terminal 4. .

  The battery pack in each of the above embodiments can be widely applied to portable terminals such as mobile phones and portable information processing terminals, and battery packs in portable electronic devices such as digital cameras.

It is a figure which shows embodiment of this invention, (A) is the side view which looked at the battery pack from the terminal side, (B) is sectional drawing in alignment with the BB line of (A), (C) is (A) It is sectional drawing in alignment with CC line | wire. In embodiment of this invention, it is a figure which shows the disassembled perspective view except a case. It is a figure which shows the modification of the connection component in embodiment of this invention, respectively. It is a figure which shows a prior art example, (A) is the side view which looked at the battery pack from the terminal side, (B) is sectional drawing which follows the BB line of (A), (C) is C- of (A). It is sectional drawing which follows a C line. In a prior art example, it is a figure which shows the disassembled perspective view except a case.

Explanation of symbols

1 battery cell
2 Protection circuit board
3 Battery negative electrode 3a, 4a Projection
4 Battery positive electrode
5 Negative connection parts
6 Positive connection parts
8 Electrical parts 10 Upper case 11 Lower case 50, 60 holes

Claims (8)

  A battery pack in which battery cells and a circuit board are accommodated in a battery case, wherein the battery pack and the circuit board are connected by press-fitting.   The battery pack according to claim 1, wherein the circuit board is disposed in close contact with a side surface of the battery case.   The battery pack according to claim 1, wherein a negative electrode connection terminal on the circuit board is smaller than a negative electrode terminal of the battery cell.   The battery pack according to any one of claims 1 to 3, wherein the battery pack is formed by press-fitting protrusions of the positive electrode terminal and the negative electrode terminal of the battery pack into holes of connection parts on the circuit board.   The battery pack according to claim 4, wherein a diameter of the protrusion is set to be slightly larger than a diameter of the hole.   The battery pack according to claim 1, wherein the connection part is formed of an elastic and conductive material.   A battery pack assembling method in which battery cells and a circuit board are housed in a battery case, wherein the positive and negative electrode terminals of the battery pack are connected to the circuit when the battery pack and the circuit board are connected. A method of assembling a battery pack, comprising the step of press-fitting into a connection component of a substrate.   A portable electronic device comprising the battery pack according to claim 1.

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