JP5362424B2 - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack advantageous to reducing a size. <P>SOLUTION: In a battery pack 1, a protection circuit 15 is fit to a unit cell 2, the unit cell 2 has a terminal portion 5, a first lead 10 is joined to the terminal portion 5, a second lead 17 is joined to the protection circuit 15, the first and second leads 10, 17 have standing portions 12, 19 standing up from bottom surfaces 11, 18, the standing portion 19 of the second lead 17 is overlapped with the peripheral part of the protection circuit 15, the standing portion 12 of the first lead 10 is overlapped with the standing portion 19 of the second lead 17, and the standing portion 12 of the first lead 10 is joined to the standing portion 19 of the second lead 17. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a battery pack in which a protection circuit is attached to a unit cell.

  With the recent thinning and miniaturization of battery packs, there is a battery pack having an exterior part in which a positive electrode lead and a negative electrode lead are taken from the sealing body side of the upper part of the unit cell and the protection circuit and the protection element are concentrated on the upper part of the unit cell It is becoming mainstream (for example, Patent Document 1 below).

  FIG. 10 shows an exploded perspective view of an example of a conventional battery pack. The battery pack 100 shown in this figure is an example of a configuration in which the protection circuit 108 is housed in a resin frame 106. One end of the lead 103 is welded to the positive electrode terminal 102 of the unit cell 101, and one end of the lead 105 is welded to the negative electrode terminal 104.

  The resin frame 106 is fixed to the unit cell 101 through a double-sided tape 107. The other end of the lead 103 is welded to the protection circuit 108, and the other end of the lead 105 is welded to one end of the protection element 109. The other end of the protection element 109 is welded to one end of the lead 110, and the other end of the lead 110 is welded to the protection circuit 108.

  When each of the above weldings is completed, the protection element 109 is accommodated in the frame 106 and the frame 106 supports the protection circuit 108. By engaging the fixing claws 113 of the frame 106 with the holes 112 of the outer cover 111, the outer cover 111 is fixed to the frame 106. A can bottom cover 114 is attached to the lower part of the unit cell 101 via a double-sided tape 115. A label 116 is attached to the entire circumference of the unit cell 101.

  FIG. 11 is a schematic diagram of a longitudinal section in a state where the protection circuit 108 is attached to the battery pack 100 of FIG. As shown in FIG. 11, the protection circuit 108 and the protection element 109 are concentrated on the upper part of the unit cell 101. In the finished product state as shown in FIG. 11, the battery pack can be made thinner and smaller. .

JP 2006-331818 A

  However, in the configuration of the battery pack as described above, there is a limit to further downsizing. Specifically, in FIG. 11, the negative electrode terminal 104 is a convex portion. The rear surface of the protection circuit 108 also forms a convex portion by the component mounting portion 117.

  In this configuration, the convex portion due to the negative electrode terminal 104 and the convex portion due to the component mounting portion 117 are opposed to each other, and a certain amount of clearance is required between the both convex portions. In this case, a space having a dimension obtained by adding a clearance to the height of both convex portions is required between the upper surface of the unit cell 101 and the back surface of the protection circuit 108. In addition, the lead 103 being bent requires a certain distance between the two surfaces facing each other by bending. For this reason, there was a limit to further miniaturization.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a battery pack that is more advantageous for downsizing.

In order to achieve the above object, a battery pack of the present invention is a battery pack in which a protection circuit is attached to a unit cell, the unit cell is provided with a terminal portion, and a first lead is joined to the terminal portion. The second lead is joined to the protection circuit, and the first and second leads form a standing part rising from the bottom surface, and the standing part of the second lead And the outer peripheral portion of the protection circuit overlap, the standing portion of the first lead and the standing portion of the second lead overlap, and the standing portion of the first lead and the The raised portion of the second lead is joined to the raised portion, and the raised portion of the first and second leads rises from two opposite sides of the bottom surface so as to sandwich the protection circuit. It is characterized by.

  According to the present invention, the battery pack can be further downsized.

1 is an exploded perspective view of a battery pack according to Embodiment 1 of the present invention. FIG. 3 shows an enlarged perspective view of a second lead according to an embodiment of the present invention, wherein FIG. 5A is a first example, and FIG. 5B is a second example. The enlarged view of the protection circuit 15 which concerns on one embodiment of this invention is shown, (a) A figure is a top view, (b) A figure is a side view, (c) A figure is a back view. It is a perspective view which shows the manufacturing process of the battery pack which concerns on one embodiment of this invention, (a) A figure is a perspective view which shows the process of attaching the double-sided tape 7 and the protection element 13, (b) The figure attaches the flame | frame 8. The perspective view which shows a process, (c) The figure is a perspective view which shows the process of attaching the 1st lead | read | reed 10. FIG. It is a perspective view which shows the manufacturing process of the battery pack which concerns on one embodiment of this invention, (a) A figure is a perspective view which shows the process of attaching the protection circuit 15, (b) A figure is the protection circuit 15 and a 1st lead | read. The perspective view which shows the process of joining this standing part 12. FIG. FIG. 5A is a schematic diagram of a longitudinal section in a state where the attachment of the protection circuit 15 to the unit cell 2 is completed in the step of FIG. 5B, and FIG. It is a perspective view which shows the manufacturing process of the battery pack which concerns on one embodiment of this invention, (a) A figure is a perspective view which shows the process of attaching the exterior cover 20 and the can bottom cover 23, (b) A figure shows the label 24. The perspective view which shows the process of affixing. The perspective view of the battery pack 1 of the state which the assembly which concerns on one embodiment of this invention was completed. The disassembled perspective view of the battery pack which concerns on Embodiment 2 of this invention. The exploded view of an example of the conventional battery pack. FIG. 11 is a schematic diagram of a longitudinal section in a state where a protection circuit is attached in the battery pack 100 of FIG. 10.

  According to the battery pack of the present invention, the first lead and the second lead do not need to be bent in the assembly process, and can be welded only by superimposing them. Moreover, the standing part which is a welding surface has overlapped with the outer peripheral part of the protection circuit, and the standing part does not protrude from the back surface of the protection circuit.

  For this reason, if there is an interval corresponding to the total thickness of the first lead and the second lead between the element terminal and the back surface of the protection circuit, the two leads can be welded. Accordingly, the height of the protection circuit from the upper part of the unit cell can be reduced, which is advantageous for downsizing the battery pack.

  In the battery pack of the present invention, it is preferable that a convex component mounting portion is provided on one surface of the protection circuit, and the component mounting portion is disposed at a position shifted from the terminal portion. According to this structure, since the terminal part of a unit cell and a component mounting part do not oppose, the front end surface of a component mounting part can be arrange | positioned below the terminal surface of a terminal part. Therefore, this also makes it possible to reduce the height of the protection circuit from the upper part of the unit cell, which is advantageous for downsizing the battery pack.

  Moreover, it is preferable that the upright portions of the first and second leads rise from two opposite sides of the bottom surface so as to sandwich the protection circuit. According to this structure, a welding surface can be increased and it becomes advantageous to ensuring joining strength.

  In addition, it is preferable that a resin is molded integrally with the unit cell, and the protection circuit is inside the molded resin. Even with this configuration, the height of the protection circuit from the upper part of the unit cell can be reduced, which is advantageous for downsizing the battery pack.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, a schematic configuration of the battery pack will be described with reference to FIG. FIG. 1 is an exploded perspective view of battery pack 1 according to Embodiment 1 of the present invention. This figure has shown the unit cell 2 and the various accessory parts attached to this. The unit cell 2 includes a power generating element in a thin rectangular outer can 3 made of, for example, aluminum or an aluminum alloy. The unit cell 2 is, for example, a rectangular lithium ion battery, and is used for a mobile phone, a mobile device, or the like.

  The opening of the outer can 3 is sealed with a sealing body 4. The sealing body 4 is provided with a negative electrode terminal 5 and a positive electrode terminal 6 which are terminal portions. A resin frame 8 is attached to the sealing body 4 via a double-sided tape 7.

  The first lead 10 is joined to the negative electrode terminal 5 by welding. A terminal 14 of the protection element 13 is joined to the positive electrode terminal 6 by welding. The first lead 10 forms a standing portion 12 that rises from the bottom surface 11. The material of the first lead 10 and the terminal 14 may be determined according to the material of the negative electrode terminal 5 and the positive electrode terminal 6, and examples thereof include nickel, iron, and stainless steel.

  The protection element 13 is joined to the terminal 16 of the substrate-like protection circuit 15 by welding. The protection element 13 and the protection circuit 15 are protection means for preventing overcharge, overcurrent, overdischarge, and the like. A second lead 17 is bonded to the protection circuit 15. Details of this will be described later with reference to FIGS.

  The outer cover 20 is fixed to the frame 8 by engaging the holes 21 of the outer cover 20 that is a resin molded product with the fixing claws 9 of the frame 8. A can bottom cover 23 is attached to the lower part of the unit cell 2 via a double-sided tape 22. A label 24 is attached to the entire periphery of the unit cell 2.

  FIG. 2 is an enlarged perspective view of the second lead 17. This figure shows a single product state before the second lead 17 is joined to the protection circuit 15. FIG. 2A is a first example, and FIG. 2B is a second example. 2A and 2B, the first lead 17 forms a standing portion 19 that rises from the bottom surface 18. In the first example of FIG. 2A, the standing portion 19 rises from two opposing sides of the bottom surface 18. In the second example of FIG. 2B, one upright portion 19 is omitted compared to the example of FIG.

  Although FIG. 2 has been described with reference to the example of the second lead 17, the description regarding FIG. 2 is the same for the first lead 10. Reference numerals of the first leads 10 are shown in parentheses in FIG.

  FIG. 3 shows an enlarged view of the protection circuit 15. This figure shows a state in which the second lead 17 having the shape shown in FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a back view.

  As shown in FIG. 3C, the bottom surface 18 of the lead 17 is bonded to the back surface of the protection circuit 15. As shown in FIGS. 3A and 3B, the second lead 17 is attached to the protection circuit 15 so that the pair of standing portions 19 sandwich the outer periphery of the protection circuit 15. As a result, the standing portion 19 and the outer peripheral portion of the protection circuit 15 overlap each other.

  As shown in FIGS. 3B and 3C, convex component mounting portions 30 and 31 are formed on the back surface of the protection circuit 15. In the example of this figure, the component mounting unit 30 mounts a protection IC (Integrated Circuit), and the component mounting unit 31 mounts an FET (Field Effect Transistor).

  Hereinafter, the battery pack according to the present embodiment will be described in the order of the manufacturing process. FIG. 4 shows a process until the first lead 10 is welded to the unit cell 2. In the process of FIG. 4A, the double-sided tape 7 is attached to the upper part of the unit cell 2. Furthermore, the terminal 14 of the protective element 13 is joined to the positive electrode terminal 6 by welding.

  In the process of FIG. 4B, the bottom surface of the frame 8 is attached to the double-sided tape 7. 4C, the bottom surface 11 of the first lead 10 is joined to the negative electrode terminal 5 exposed at the opening of the frame 8 by welding.

  FIG. 5 shows a process until the protection circuit 15 is attached to the unit cell 2. 5A, the protection circuit 15 is placed on the frame 8, and the terminal 16 of the protection circuit 15 is joined to the protection element 13 by welding.

  In the step of FIG. 5B, the standing part 19 of the second lead 17 and the standing part 12 of the first lead 10 are joined by welding. By this step, the attachment of the protection circuit 15 to the unit cell 2 is completed. The welding may be performed on at least one of the two surfaces of the pair of standing portions 12. When welding on both surfaces, it is advantageous in terms of welding strength.

  Further, at least one of the first lead 10 and the second lead 17 is assumed to have one standing portion 12 (17) as shown in FIG. It is good.

  As shown in FIG. 5B, when the protection circuit 15 is placed on the frame 8, the first lead is placed on the bottom surface 18 (FIG. 3C) of the second lead 17 joined to the protection circuit 15. The bottom surface 11 of FIG. 10 (FIG. 5A) is opposed. Furthermore, the standing portion 12 of the first lead 10 overlaps with the standing portion 19 (FIG. 5A) of the second lead 17.

  FIG. 6A shows a schematic diagram of a longitudinal section in a state where the attachment of the protection circuit 15 to the unit cell 2 is completed in the step of FIG. 5B. FIG. 6B shows an enlarged view of a portion A in FIG. As shown in FIG. 6A, the convex component mounting portions 30 and 31 are arranged at positions shifted from the negative electrode terminal 5. According to this configuration, since the negative electrode terminal 5 and the component mounting portions 30 and 31 are not opposed to each other, the tip surfaces of the component mounting portions 30 and 31 are closer to the sealing body 4 side (lower side) than the terminal surface of the negative electrode terminal 5. ) Can be arranged.

  On the other hand, the first lead 10 and the second lead 17 do not need to be bent in the assembly process, and can be welded only by superimposing them. Further, as shown in FIGS. 3A, 3B, and 5A, the second lead 17 has a standing portion 19 that is a welded surface and an outer peripheral portion of the protection circuit 15 overlapping each other. The standing portion 19 does not protrude from the back surface of the protection circuit 15. For this reason, if there is an interval corresponding to the total thickness of the first lead 10 and the second lead 17 between the negative electrode terminal 5 and the back surface of the protection circuit 15, both leads can be welded.

  Specifically, as shown in FIG. 6B, the bottom surface 11 of the first lead 10 overlaps the bottom surface 18 of the second lead 17 joined to the protection circuit 15. In FIG. 6B, the interval S2 between the negative electrode terminal 5 and the back surface of the protection circuit 15 is within a range in which the tip surfaces of the component mounting portions 30 and 31 do not contact the sealing body 4 in FIG. If so, the total dimension of the thickness t1 of the first lead 10 and the thickness t2 of the second lead 17 can be reduced.

  In the present embodiment, as described above, the negative electrode terminal 5 and the component mounting portions 30 and 31 do not face each other, and the tip surfaces of the component mounting portions 30 and 31 are arranged closer to the sealing body 4 than the terminal surface of the negative electrode terminal 5. Since this is possible, it is advantageous to reduce the interval S2.

  As the interval S2 is reduced, the interval S1 between the sealing body 4 and the back surface of the protection circuit 15 is reduced in FIG. As a result, an increase in the height of the battery pack due to the addition of accessories can be suppressed, which is advantageous for downsizing.

  FIG. 7 shows a process until the label 24 is attached to the unit cell 2. In the step of FIG. 7A, the hole 21 of the exterior cover 20 and the fixing claw 9 of the frame 8 are engaged. As a result, the exterior cover 20 is fixed to the frame 8.

  Furthermore, a can bottom cover 23 is attached to the lower part of the unit cell 2 via a double-sided tape 22. In the process of FIG. 7B, the label 24 is attached to the entire periphery of the unit cell 2.

  FIG. 8 shows a perspective view of the battery pack 1 in a state where the assembly is completed. In the state of FIG. 8, the various accessory parts shown in FIG. 1 are accommodated in the exterior cover 20. As described with reference to FIG. 6A, in the present embodiment, the interval S <b> 1 between the sealing body 4 and the back surface of the protection circuit 15 can be reduced. For this reason, an increase in the height h of the battery pack 1 can be suppressed, which is advantageous for downsizing.

(Embodiment 2)
FIG. 9 is an exploded perspective view of battery pack 40 according to Embodiment 2 of the present invention. In the configuration of FIG. 1 of the first embodiment, a protection circuit 15 is mounted on a pre-shaped frame 9. On the other hand, in the second embodiment, after the protection circuit 15 is mounted, a resin is injected between the outer cover 42 and the unit cell 2 to integrally mold the unit cell 2 and the accessory parts. .

  Except for this point, the first and second embodiments have the same configuration. For this reason, in FIG. 9, the same number is attached | subjected to the part of the same structure as FIG. 1, and detailed description is abbreviate | omitted.

  In FIG. 9, an insulating plate 41 is placed on the sealing body 4 to insulate between the sealing body 4 and the protection circuit 15. The first lead 10 is joined to the negative electrode terminal 5 by welding. A terminal 14 of the protection element 13 is joined to the positive electrode terminal 6 by welding. The protection element 13 is joined to the terminal 16 of the substrate-like protection circuit 15 by welding.

  Similarly to the process shown in FIG. 5B, the standing portion 19 of the second lead 17 and the standing portion 12 of the first lead 10 are joined by welding, and the protection circuit 15 is connected to the unit cell 2. It is attached.

  After the exterior cover 42 is placed so as to cover the protection circuit 15, the unit cell 2 is mounted on the mold, a resin is injected between the exterior cover 42 and the unit cell 2 and cured, and the integrally molded resin 43 is formed. Form. As a result, the unit cell 2 and the accessory part are integrally molded by the integral molding resin 43.

  In FIG. 9, for convenience of illustration, the integrally molded resin 43 is illustrated separately from various accessory parts. In the completed state of the battery pack 40, the integrally molded resin 43 is between the upper part of the unit cell 2 and the exterior cover 42, and the various accessory parts are included in the integrally molded resin 43.

  Similar to the battery pack 1 of FIG. 1, a can bottom cover 23 is attached to the lower part of the unit cell 2 via a double-sided tape 22. A label 25 is attached to the entire periphery of the unit cell 2.

  Also in the second embodiment, the configuration when the protection circuit 15 is attached to the unit cell 2 is the same as that in FIGS. 6A and 6B of the first embodiment. For this reason, also in Embodiment 2, the height of the protection circuit 15 from the upper part of the unit cell 2 can be lowered, and the battery pack can be further reduced in size as in Embodiment 1.

  As described above, according to the present invention, since the battery pack can be further reduced in size, the battery pack according to the present invention is useful as a battery pack used for, for example, a mobile phone or a mobile device.

DESCRIPTION OF SYMBOLS 1,40 Battery pack 2 Unit cell 5 Negative electrode terminal 6 Positive electrode terminal 10 1st lead 11 Bottom surface part of 1st lead 12 Standing part of 1st lead 15 Protection circuit 17 2nd lead 18 2nd lead Bottom portion 19 Second lead standing portion 30, 31 Component mounting portion 43 Integrated molding resin

Claims (3)

A battery pack in which a protection circuit is attached to a unit cell,
The unit cell is provided with a terminal portion,
A first lead is joined to the terminal portion, and a second lead is joined to the protection circuit,
The first and second leads form a standing part rising from the bottom surface,
The upright portion of the second lead and the outer peripheral portion of the protection circuit overlap,
The upright portion of the first lead and the upright portion of the second lead overlap,
Bonding the upright portion of the first lead and the upright portion of the second lead ;
The battery pack according to claim 1, wherein the standing portions of the first and second leads rise from two opposite sides of the bottom surface so as to sandwich the protection circuit .   2. The battery pack according to claim 1, wherein a convex component mounting portion is provided on one surface of the protection circuit, and the component mounting portion is disposed at a position shifted from the terminal portion. Wherein the unit cell and integrally has a resin is molded, the battery pack according to claim 1 or 2, wherein the protection circuit is internal to the molded resin.

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