JP2013080570A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack having excellent appearance quality of outer package label, and capable of exhibiting an alteration display function of an end user appropriately.SOLUTION: In a battery pack 1, flat rectangular parallelepiped unit cells 2A, 2B each consisting of a polymer cell are housed in the unit cell housing sections 30A, 30B of a case member 3 while being juxtaposed. A protection circuit board 4 is housed in a board housing section 301 so that the principal surface of the board body 40 is in parallel with the principal surface of the unit cell. An outer package label 7 is disposed so that the principal surface 701 of a laminate structure including a label layer and a resin sheet layer 72 is stuck to the case member 3 and the upper surfaces 20A, 20B of unit cells 2A, 2B. Consequently, mixture of bubbles is prevented on the boundary surface of a package sheet and the unit cell.

Description

  The present invention relates to a battery pack that encloses a secondary battery, and more particularly, to a technology that favorably produces a high-capacity, small, and thin battery pack that uses a lithium ion polymer battery.

In recent years, a battery pack in which a secondary battery that can be repeatedly charged and used is housed in a case member has been widely used. Battery packs are widely used as a main power source or backup power source for notebook personal computers, mobile phones, PDAs, and other various electronic devices.
In particular, recently, battery packs using high-capacity lithium ion polymer batteries are increasing in smartphones and tablet terminals.

  In a typical battery pack configuration, one or a plurality of flat rectangular parallelepiped lithium ion polymer batteries are used, and a protection circuit board is connected to the electrode terminals (positive electrode tab, negative electrode tab) of each unit cell. These components are housed in a predetermined case member, and the protection circuit board is supported at a predetermined position by the board holder. An exterior label is wound around the outer periphery of the case member.

JP 2010-21029 A JP 2010-276992 A JP 2003-282040 A

However, the conventional battery pack has the following problems.
That is, there is a problem that it is difficult to properly attach the exterior label to the unit cell or the like. The outer label is made of a relatively flexible material because it follows the shape of the case member and the unit cell, so it is made of a relatively flexible material, but air bubbles are mixed between the outer label and the unit cell, thereby reducing the appearance quality. There is. FIG. 12A is a partial cross-sectional view of a conventional battery pack showing the appearance of the exterior label 7X in which bubbles are generated. In this example, an exterior label 7X (a laminate of the adhesive layer 71 and the laminate layer 70) is attached to the main surface of the unit cell 2A, but a plurality of bubbles are mixed in the interface between the adhesive layer 71 and the unit cell 2A. Yes. Such a problem of air bubbles becomes prominent in proportion to an increase in the area where the exterior label is attached to the unit cell 2A due to the size of the unit cell 2A becoming larger.

  Thirdly, it is necessary to appropriately prevent wrinkles from appearing on the exterior label and to display end-user tampering. FIG. 13A shows a state in the vicinity of the extended end portion 702X of the conventional exterior label. A slit 74X is provided at the end of the extended end portion 702X, and when the end user carelessly disassembles the battery pack, it indicates that the slit has been broken and has been tampered with. Due to use over time or torsional stress, wrinkles are generated on the exterior label around the slit 74X, deteriorating the appearance quality, and unnecessary tears are generated, resulting in inaccurate tampering display.

Each of the above problems becomes particularly apparent when a lithium ion polymer battery whose appearance dimensions and shape are difficult to stabilize is used for a unit cell.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery pack that has a good appearance quality of an exterior label and can appropriately exhibit an end-user tampering display function.

  In order to solve the above problems, a battery pack of the present invention includes a unit cell having a rectangular parallelepiped external shape including rectangular first and second main surfaces and four side surfaces having a smaller area than the two main surfaces. A circuit board electrically connected to at least one of a positive electrode side and a negative electrode side of the battery, a frame-shaped unit cell storage unit that surrounds and stores the unit cell from the four side surface directions excluding the two main surfaces, and A case member having a dish-like substrate storage part that supports the circuit board from the bottom side and stores the circuit board in parallel with the unit cell, and the first main body of the unit cell stored in the unit cell storage part. A sheet member that covers the surface, and an exterior label that is attached so as to cover at least the second principal surface of the unit cell, wherein the principal surface portion of the exterior label includes a label layer that is exposed to the outside. Resin sheet layer with higher rigidity than the label layer And configured to have a laminated structure including.

Here, the said resin sheet layer can also be comprised with a polycarbonate.
Also, it has a plurality of extended end portions that extend from the periphery of the main surface portion and are attached to the first main surface of the unit cell, and at least one of the extended end portions, It can also be set as the structure by which the V-shaped slit is formed.
Moreover, the position of the top part of the said V-shaped slit can also be set as the structure provided according to the position near the center from the periphery of the said sheet | seat member.

Moreover, the said exterior label WHEREIN: The said resin sheet layer can also be set as the structure provided in the position except the said extended edge part.
Further, the case member may be configured such that two or more unit cells are accommodated in a state of being arranged in parallel with each other.
The unit cell may be a lithium ion polymer battery.

  The battery pack according to claim 1 having the above-described configuration forms a laminated structure in which a label layer and a resin sheet layer having higher rigidity than the label layer are laminated on at least a main surface portion covering the second main surface of the unit cell. . Thereby, since the flatness of the exterior label in the main surface portion can be maintained as compared with the case where the label layer is used alone, bubbles can be effectively prevented from entering between the unit cell and the exterior label at the time of label sticking. Therefore, even when a lithium ion polymer battery having a relatively soft exterior is used for a unit cell, or even when the unit cell to which the exterior label is attached has a relatively large area, a battery pack with excellent appearance quality can be realized.

Moreover, by limiting the area | region which arrange | positions a resin sheet layer to a main surface part, the exterior label thickness of an area | region other than this can be made thin and can be made soft. Thereby, the overall thickness of the battery pack can be reduced favorably, and the exterior label can be easily bent in accordance with the shape of the unit cell, so that excellent workability can be exhibited.
Further, in the battery pack according to claim 3, since the V-shaped slit having a certain opening angle is provided in at least one of the extended end portions extending from the periphery of the main surface portion, In use over time, even if the exterior case is twisted or bent, wrinkles at the end of winding of the exterior label or misalignment of the exterior label can be prevented, and high appearance quality can be maintained. In addition, the anti-tampering function can be exhibited well.

It is a perspective view which shows the external appearance structure of the battery pack 1 which concerns on embodiment of this invention. 2 is a development view showing an internal configuration of the battery pack 1. FIG. 2 is a development view showing an internal configuration of the battery pack 1. FIG. It is a partial front view which shows the structure of a case member. It is a fragmentary sectional view showing the composition of a case member, and the fitting state of a substrate holder and a case member. It is a perspective view which shows the structure of a substrate holder. It is a fragmentary sectional view which shows the structure of an exterior label. It is a partial front view which shows the arrangement | positioning relationship of a case member, a board | substrate, and a board | substrate holder. It is a perspective view which shows the manufacturing process of a battery pack. It is a perspective view which shows the manufacturing process of a battery pack. It is a perspective view which shows the manufacturing process of a battery pack. It is a fragmentary sectional view which shows the interface mode of an exterior label and a unit cell. It is a partial front view which shows the mode of an exterior label.

Embodiments of the present invention will be described below. The embodiment is an example used for easily explaining the configuration, operation, and effect of the present invention, and the present invention is not limited to the following form except for its essential features. Absent.
<Configuration of battery pack 1>
1A and 1B are external views of a battery pack 1 according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the battery pack 1 has a flat rectangular parallelepiped external shape in which the X direction is the longitudinal direction, the Y direction is the thickness direction, and the Z direction is the height direction. Has a main surface. Connector wiring 41 is exposed from the inside through the notch 31 at the upper part of the battery pack 1. On the outer periphery of the battery pack 1, an exterior label 9 having a main surface portion 701 and extended end portions 702A to 702D is attached. The battery pack 1 is assumed to be a tablet terminal as a power supply target device, but of course is not limited to this.

As an example of the battery size, the length in the X direction is about 138 mm, the length in the Y direction is about 5 mm, and the thickness in the Z direction is about 100 mm. However, other size settings are possible.
<Internal configuration of battery pack 1>
2 and 3 are development views showing the internal configuration of the battery pack 1, respectively. 2 is a development view looking down from the exterior label 7 side, and FIG. 3 is a development view looking down from the resin sheet 6 side.

As shown in FIG. 2, the battery pack 1 includes two unit cells 2A and 2B as main components, and the lead plate 27A (27B), the breaker 25A (25B), and the lead plate in order from the unit cell 2A (2B). 26A (26B) is electrically connected. The lead plate 26A (26B) is electrically connected to the protection circuit board 4.
The unit cell 2 </ b> A (2 </ b> B) is stored in the frame-shaped unit cell storage unit 30 </ b> A (30 </ b> B) of the case member 3, and the protection circuit board 4 is stored in the substrate storage unit 301 of the case member 3. The resin sheet 6 is attached to the lower surfaces 28A and 28B of the unit cells 2A and 2B exposed from the case member 3, and the exterior label 7 is attached to the upper surfaces 20A and 20B.

(Peripheral structure of unit cells 2A and 2B)
A unit cell 2A (2B) shown in FIGS. 2 and 3 is a known lithium ion polymer battery, and has a rectangular first main surface (lower surface 28A (28B)) and second main surface (upper surface 20A (20B)). The outer appearance of a flat rectangular parallelepiped having four side surfaces smaller in area than the two main surfaces. A rectangular-shaped positive electrode plate, a separator, and a negative electrode plate are laminated, and a power generation element (not shown) impregnated with an electrolyte is wrapped with a laminate outer package and internally sealed from three sides. The positive electrode tab 23A (23B) is connected to the positive electrode plate, and the negative electrode tab 22A (22B) is connected to the negative electrode plate. The tabs 22A (22B) and 23A (23B) are the top sealing portions 21A (21B) of the laminate outer package. It extends to the outside and is used as an electrode terminal.

Between the positive electrode tab 23A (23B) and the lead plate 27A (27B) and the negative electrode tab 22A (22B), an insulating plate 24A (24B) is fixed using an adhesive tape or the like to prevent a short circuit.
In addition, as unit cell 2A (2B), it is not limited to a lithium ion polymer battery, Other secondary batteries, such as a nickel metal hydride battery and a nickel cadmium battery, can be used.

Further, the “cuboid” is not mathematically exact, and includes those having some curved surfaces.
A PTC element is used as the breaker 25A (25B). The breaker 25A (25B) cuts off energization when the temperature of the unit cell 2A (2B) rises excessively during charging / discharging of the battery pack 1. In the battery pack 1, the breaker 25A (25B) is electrically connected to the positive terminal 23A (23B) of the unit cell 2A (2B) via the lead plate 27A (27B), and is connected to the protective circuit board via the lead plate 26A (26B). 4 is electrically connected.

The breakers 25A and 25B may use safety elements other than the PTC elements. For example, a thermal element such as an NTC (Negative Temperature Coefficient) element or a thermal fuse element, and various electric elements used for other battery control can be used.
The lead plates 26A, 26B, 27A, and 27B are all made of a metal material having excellent conductivity, such as a nickel plate (NiP).

The protection circuit board 4 is configured by mounting various electrical elements and connector wirings 41 on a strip-like board body 40 made of a composite material containing glass, epoxy resin, or the like. On the upper surface of the protection circuit board 4, test point terminals 42 are arranged at predetermined positions. A connector portion 410 connected to the power supply target device side is attached to the tip of the connector wiring 41.
(Case member 3)
The case member 3 is an injection molded product made of a resin material (ABS, PPC, PC, etc.) excellent in heat resistance and mechanical strength, for example, a PC (polycarbonate) resin. As shown in FIGS. 2 and 3, two frame-shaped openings (unit cell storage units 30 </ b> A and 30 </ b> B) arranged in parallel in the X direction according to the shapes of the unit cells 2 </ b> A and 2 </ b> B, The plate-shaped substrate storage portion 301 is configured to match the shape of the protection circuit substrate 4.

  The unit cell storage unit 30A (30B) surrounds and stores each unit cell 2A (2B) from each of the four side surfaces. The substrate storage unit 301 has a bottom surface parallel to the planar direction (XZ direction) of the main surface portions 20A and 20B of the respective unit cells 2A and 2B, and supports the protection circuit substrate 4 from the back surface. Partial front view (FIG. 4A) of case member 3 showing the peripheral structure of substrate storage portion 301, and AA ′ line cross-sectional view (FIG. 5A), BB ′ line cross-sectional view As shown in the figure (FIG. 5B), a plurality of ribs 302 to 308 for positioning the protection circuit board 4 are erected on the bottom surface inside the storage portion 301. The ribs 302 to 308 support and store the protection circuit board 4 from the back side in the board storage unit 301.

  Here, as one of the features of the first embodiment, the fitting is performed in the same order as the fitting grooves 53 </ b> A to 53 </ b> C of the board holder 5 at a position corresponding to the peripheral edge of the protection circuit board 4 housed in the board housing portion 301. Fitting claws 35A and 35B that are fitted in the same order as the rear ends 540A and 540B of the engaging claws 34A to 34C and the engaging claws 54A and 54B are provided upright. The tips of the plurality of fitting claws 34A to 34C, 35A, and 35B project from the inside of the board storage portion 301, and the fitting claws 34A to 34C, 35A, and 35B are in the thickness (Y) direction of the protective circuit board 4. Is erected along.

  By providing the fitting claws 34A to 34C, 35A, and 35B at such positions, it is not necessary to cut out the outer shape of the substrate body 40 in accordance with the positions of the fitting claws 34A to 34C, 35A, and 35B. The protection circuit board 4 having a straight shape and a sufficient mounting area can be used. In addition, since it is not necessary to produce a specially shaped substrate body, production costs can be suppressed, and there is an advantage that an existing protection circuit substrate can be used as it is. Further, even if the protection circuit board 4 is stored in the board storage portion 301, the protection circuit board 4 does not interfere with any of the fitting claws 34A to 34C, 35A, 35B and the board holder 5, so that the protection circuit board 4 is damaged. Can be avoided.

  Further, as a further contrivance, as shown in an outer front view of the case member 3 at a position corresponding to the substrate storage portion 301 (FIG. 4B), a communication hole is formed in the root portion of the fitting claws 34A to 34C, 35A, 35B. 32A to 32C, 33A, and 33B are provided. Among these, the communication holes 33A and 33B engage with the tips of the engagement claws 54A and 54B of the substrate holder 5. At the time of manufacture, an operator passes through each of the communication holes 32A to 32C, 33A and 33B, the fitting state of the fitting claws 34A to 34C and the fitting grooves 53A to 53C from the outside, and the engagement claws 54A and 54B and the communication hole 33A. , 33B can be visually recognized.

Here, FIGS. 5C and 5D illustrate a fitting state between the fitting claw 34B and the fitting groove 53B. When the fitting failure occurs, as shown in FIG. 5D, the fitting claw 34B abuts the side surface of the fitting groove 53B, and the appearance of the interface can be confirmed through the communication hole 32B. .
On the other hand, when the fitting claw 34B is correctly fitted to the fitting groove 53B, the fitting claw 34B is hidden behind the fitting groove 53B and hardly visible from the communication hole 32B as shown in FIG. .

Here, as a further contrivance, by forming the substrate holder 5 in a color different from that of the case member, the distinction between the poor fitting state and the fitting state can be recognized very easily.
Further, by forming the fitting claws 34A to 34C, 35A, and 35B so as to have the communication holes 32A to 32C, 33A, and 33B at the root portion, the general mold can be used without using an expensive slide mold. The case member 3 can be formed by injection molding at a relatively low cost using a molding die composed of only a core. Specifically, the case member 3 can be injection-molded using only the upper and lower punching molds in the Y direction of the case member 3 by using the communication holes 32A to 32C, 33A, and 33B as undercut portions.

(Substrate holder 5)
The substrate holder 5 is configured as an injection-molded product of the same resin material as the case member 3, and is disposed so as to cover the upper surface of the protection circuit substrate 4 stored in the substrate storage portion 301. The protective circuit board 4 is sandwiched. As shown in the perspective view of the substrate holder 5 (FIG. 6), the substrate holder 5 is an elongated body adapted to the form of the protection circuit board 4, and the test point terminal 42 of the protection circuit board 4 is provided on the upper surface portion 50. A window 51 is formed to expose the. Engagement claws 54A and 54B formed by juxtaposing a plurality of triangular prismatic protrusions protruding in the reverse Y direction are formed at both ends in the longitudinal (X) direction. The engagement claws 54A and 54B are inserted into the communication holes 33A and 33B of the case member 3 and engaged with the peripheral edges of the communication holes 33A and 33B. Fitting grooves 53 </ b> A to 53 </ b> C that fit in the same order as the fitting claws 34 </ b> A to 34 </ b> C are formed on both side surfaces in the longitudinal (X) direction of the substrate holder 5. Further, the fitting claws 35A and 35B are fitted in the rear end portions 540A and 540B of the engagement claws 54A and 54B in the same order. The flange 52 serves to hold down the base portion of the connector wiring 41 on the protection circuit board 4.

The substrate holder 5 is formed in a color different from that of the case member 3 so that the fitting state with the case member 3 can be easily confirmed at the time of manufacture. Coloring may be performed by adjusting the color of the resin material or by coloring after molding.
The resin sheet 6 is a PC (polycarbonate) sheet member having a certain thickness and has an area equivalent to one main surface of the battery pack 1. The unit cells 2A and 2B are attached to the lower surfaces 28A and 28B to protect the unit cells 2A and 2B from the outside.

(Exterior label 7)
The exterior label 7 is a sheet member made of an insulating material and mainly covers the upper surfaces 20A and 20B of the unit cells 2A and 2B stored in the unit cell storage units 30A and 30B of the case member 3, and the outside and the unit cells 2A and 2B. Insulate from. Information such as battery standards is displayed on the surface. As shown in FIG. 2, the exterior label 7 includes a rectangular main surface portion 701 that matches the upper surface shape and size of the battery pack 1, and extended end portions 702 </ b> A to 702 </ b> D extending from four sides of the main surface portion 701. Composed. V-shaped slits 74 </ b> A to 74 </ b> D are formed in at least one of the extended end portions 702 </ b> A to 702 </ b> D (here, all) by performing a cutting process from the end side toward the main surface portion 701. The main surface portion 701 is attached to the upper surfaces 20A and 20B of the unit cells 2A and 2B, and the extended end portions 702A to 702D are wound and attached to the lower surfaces 28A and 28B of the unit cells 2A and 2B. In the state where the extended end portions 702A to 702D are adhered, the V-shaped slits 74A to 74D exist at positions closer to the center from the periphery of the resin sheet 6 as shown in FIG.

  A sectional structure of the exterior label 7 is shown in FIG. The main surface portion 701 of the exterior label 7 has a structure in which a glue layer 73, a resin sheet layer 72, an adhesive layer 71, and a laminate layer (label layer) 70 are sequentially laminated from the side facing the unit cell sides 2A and 2B. Is done. The laminate layer 70 is a surface exposed to the outside. The resin sheet layer 72 is made of a resin material (for example, a resin material similar to the resin sheet 6), and is made of a sheet member having at least higher rigidity than the laminate layer 70. On the other hand, the region other than the main surface portion 701 is composed only of the adhesive layer 71 and the laminate layer 70.

  Here, the effect of using the exterior label 7 will be described. In the conventional exterior label, as shown in the sectional view of FIG. 12A, the exterior label 7X consisting only of the adhesive layer 71 and the laminate layer 70 is attached to the unit cell 2A. Therefore, there is a problem that air bubbles are mixed between the unit cell 2A and the adhesive layer 71 to deteriorate the appearance quality. In particular, when a soft lithium ion polymer battery is used for a unit cell, since it is necessary to affix the exterior label 7X by hand, air bubbles easily enter, and this problem becomes significant. On the other hand, in the battery pack 1, the strength of the exterior label 7 on the main surface portion 701 is improved by laminating a highly rigid resin sheet layer 72 in the region of the main surface portion 701 in which bubbles are particularly likely to be mixed. Maintenance). Thus, as shown in FIG. 12 (b), when the exterior label 7 is stuck, air bubbles are prevented from being mixed between the unit cells 2A, 2B and the exterior label 7, and the exterior cells 7A, 2B are covered with the exterior cells. The label 7 can be stuck tightly. The effect of the exterior label 7 is particularly effective when the unit cells 2A and 2B made of a lithium ion polymer battery having a large area where bubbles are easily generated and the exterior is soft are used.

  Further, as shown in FIG. 7, the extended end portions 702 </ b> A to 702 </ b> D (only 702 </ b> D is shown in FIG. 7) have a two-layer structure of an adhesive layer 71 and a laminate layer 70, and the thickness is set thin. In this way, in the exterior label 7, the thickness of the exterior label 7 is increased only in the region (main surface portion 701) where air bubble generation is to be prevented, and other thicknesses are set to be thinner. Thinning can be effectively achieved. Further, by not providing the resin sheet layer 72 at the extended end portions 702A to 702D, the exterior label 7 can be easily bent, and the exterior label 7 is made to follow the shape of the unit cells 2A, 2B and the case member 3. The adhesion can be improved.

  As an example of the thickness of each layer of the exterior label 7, the adhesive layer 73 is 40 μm, the resin sheet layer 72 is 150 μm, the adhesive layer 71 is 20 μm, and the laminate layer 70 is 25 μm. From the viewpoint of the protective effect of the battery pack 1 and the sticking property at the time of manufacture, the maximum total thickness of the adhesive layer 71 and the laminate layer 70 should be set to 45 μm, and the maximum total thickness of the glue layer 73 and the resin sheet layer 72 should be set to 195 μm. is there.

  Next, effects of the V-shaped slits 74A to 74D will be described. The V-shaped slits 74 </ b> A to 74 </ b> D display that the end user has broken and tampered when the inside of the battery pack 1 is carelessly disassembled. Here, FIG. 13A shows a slit 74X provided in the conventional extended end 702X. The slit 74X is a simple cut, but when the battery pack is used, if it receives a twisting or bending stress, the extended end portion 702X of the exterior label may be wrinkled. In addition, if the extended end portion 702X is partially peeled or misaligned, a large tear is generated from the slit 74X, which deteriorates the appearance quality and makes it difficult to accurately display tampering. This problem is relatively likely to occur when a lithium ion polymer battery is used as the unit cell.

  On the other hand, a V-shaped slit (74D here) of the battery pack 1 is shown in FIG. The slit 74D is set to a cut shape having a certain opening angle. As a result, even when the battery pack 1 is used over time, even if a twisting or bending stress is applied, wrinkles are not generated at the extended end portions 702A to 702D of the outer label 7 and the outer label 7 is not displaced. Appearance quality can be maintained. Moreover, the falsification display function of the exterior label 7 can be exhibited well.

Here, by providing the V-shaped slits 74A to 74D at positions closer to the center than the peripheral edge of the resin sheet 6, it is possible to prevent unnecessary tears from being generated from the V-shaped slits 74A to 74D with use over time. Can display the falsification display function.
(About the overall effect of the battery pack 1)
In the battery pack 1 having the above configuration, the various effects described above are exhibited at a high level.

  That is, at the time of manufacture, the unit cells 2A and 2B are stored in parallel in the unit cell storage units 30A and 30B of the case member 3, and in parallel with the main surfaces 20A and 20B (28A and 28B) of the unit cells 2A and 2B. The protection circuit board 4 is stored in the board storage part 301 having the arranged bottom part. At this time, the thickness of the battery pack 1 can be reduced by arranging the main surface of the substrate body 40 in parallel with the main surfaces 20A and 20B (28A and 28B) of the unit cells 2A and 2B. Further, the protective circuit board 4 is sandwiched between the board housing portion 301 and the board holder 5, and the unit cells 2 </ b> A and 2 </ b> B are covered with the resin sheet 6 and the exterior label 7. With such a device, the battery pack 1 realizes a so-called single case structure. Therefore, as compared with the conventional case where a double case structure formed by ultrasonic welding of two case members is employed, it is possible to realize a reduction in thickness and size, and to manufacture easily. In addition, since both the unit cells 2A and 2B are housed in the resin case member 3 having a certain strength, the battery pack 1 having sufficient strength is realized.

Furthermore, by disposing the resin sheet layer 72 on the main surface portion 701 of the exterior label 7, it is possible to effectively prevent air bubbles from being mixed between the exterior label 7 and the unit cells 2 </ b> A, 2 </ b> B, while improving the appearance quality, By limiting the region in which the layer 72 is disposed only to the main surface portion 701 of the exterior label 7, the overall thickness of the battery pack 1 can be reduced.
In addition, the V-shaped slits 74A to 74D are provided in the extended end portions 702A to 702D of the exterior label 7 so as to prevent the generation of wrinkles and unnecessary tears of the exterior label 7 while maintaining the tampering display function. The effect of improving the appearance quality of the pack 1 can also be expected.

<Method for Manufacturing Battery Pack 1>
Next, an example of a method for manufacturing the battery pack 1 will be described with reference to the drawings.
(Preparation for processing of unit cells 2A and 2B)
First, flat rectangular lithium ion polymer unit cells 2A and 2B are prepared (FIG. 9A). Insulating paper 24A (24B) is disposed on the top sealing portion 21 on the lower surface 28A (28B) side of each unit cell 2A (2B) using an adhesive tape. The negative electrode tab 22A (22B) and the positive electrode tab 23A (23B) are aligned to a predetermined length.

Next, the lead plates 26A (26B) and 27A (27B) are connected to the breaker 25A (25B) by direct spot welding. At this time, attention should be paid to the welding position shift. Thereafter, the lead plate 27A (27B) is spot welded to the positive electrode tab 23A (23B).
Next, the upper part of the lead plate 27A (27B) is bent toward the main surface 20A (20B), and the positive electrode tab 23A (23B) is sandwiched (FIG. 9A).

(Preparation for assembly of protection circuit board 4)
Next, the connector wiring 41 is electrically connected to the board body 40 to produce the protection circuit board 4.
The lead plates 26A and 26B and the negative electrode tabs 22A and 22B are series-spot welded to the protective circuit board 4 to be electrically connected (FIG. 9B).

(Assembly processing of battery pack 1)
Next, the unit cell 2A (2B) is stored with the main surface 28A (28B) facing up in the unit cell storage unit 30A (30B) of the case member 3. Further, the protection circuit board 4 is stored in the board storage portion 301, and the connector wiring 41 is fitted into the cutout portion 31 so as to be exposed to the outside. And the upper surface of the protection circuit board 4 is coat | covered with the board | substrate holder 5, and each fitting nail | claw 34A-34C is fitted to fitting groove | channel 53A-53C in the same order. Further, the tips of the engagement claws 54A and 54B are inserted into the communication holes 35A and 35B in the same order, and the rear ends 540A and 540B of the engagement claws 54A and 54B are engaged with the fitting claws 35A and 35B in the same order (see FIG. 10 (a)). Thereby, the substrate holder 5 is fixed to the case member 3 side. At this time, as shown in FIG. 4B, the fitting claws 34A to 34C and the fitting grooves 53A to 53C are fitted through the communication holes 33A to 33C and the engagement claws 54A and 54B are engaged accurately. It can be confirmed whether or not

  That is, as described above, for example, when the fitting claws 34A to 34C of the case member 3 and the fitting grooves 53A to 53C of the substrate holder 5 cause poor fitting, the fitting claws 34A to 34C are inserted into the fitting groove 53A. Abuts on the side surface of .about.53C. When the communication holes 33A to 33C having a rectangular opening periphery are viewed, the interface where the fitting claws 34A to 34C and the fitting grooves 53A to 53C are in contact is parallel to one side of the peripheral edge of the communication holes 33A to 33C. It is exposed (see FIG. 5 (d)).

On the other hand, when the fitting claws 34A to 34C of the case member 3 and the fitting grooves 53A to 53C of the substrate holder 5 are accurately fitted, the fitting claws 34A to 34C are formed by the fitting grooves 53A to 53C. Since it is hidden, only the substrate holder 5 can be seen from the communication holes 33A to 33C (see FIG. 5C).
By forming the case member 3 and the substrate holder 5 in different colors, it is possible to more easily distinguish between such a poor fitting state and a fitting state.

Accordingly, since the operator can easily visually check the appearance defect due to insufficient fitting, the presence or absence of internal wiring breakage, and the like, it can be expected to improve the manufacturing efficiency, the yield, and the quality.
After confirming the fitted state and the engaged state as described above, the resin sheet 6 is uniformly applied while taking care not to allow foreign matter to enter the main surfaces 28A, 28B of the unit cells 2A, 2B. Adhere (FIG. 10 (b)).

  Thereafter, the main surface portion 701 of the exterior label 7 is attached to the upper surfaces 20A and 20B of the unit cells 2A and 2B in consideration of foreign matter contamination. Further, the extended end portions 702A to 702D are bent in accordance with the side surface shape of the case member 3 and attached to the peripheral area of the resin sheet 6 (FIG. 11). At this time, the V-shaped slits 74 </ b> A to 74 </ b> D formed in the extended end portions 702 </ b> A to 702 </ b> D are adjusted so as to exist at positions near the center in the peripheral region of the resin sheet 6.

Thus, the battery pack 1 is completed.
<Other matters>
In the above embodiment, the number of unit cells included in the battery pack 1 is two, but it may be only one or three or more.
Further, the substrate stored in the substrate storage unit 301 is not limited to the protection circuit substrate 4, and may be another substrate such as a wiring substrate.

Further, the number of combinations of the fitting portion and the fitted portion for fixing the case member and the substrate holder is not limited to the number of combinations of the fitting claw and the fitting groove. In any case, it is desirable to form a communication hole as much as possible at the base of the fitting claw in order to confirm the fitting state between the fitting claw and the fitting groove at the time of manufacture.
Further, the combination of the fitting claw and the engaging portion formed on the case member and the substrate holder is not limited to the combination of the fitting claw (projecting portion) and the fitting groove, and the engagement claw and the communication hole. Therefore, for example, the engagement (fitting) claws may be engaged (engaged) with each other, or a combination of dowels and dowel holes may be used.

  Moreover, although the V-shaped slit was illustrated as a slit formed in an exterior label by this invention, it is not limited to this, A fixed effect is acquired even if it forms a rectangular-shaped slit. However, the V-shaped slit having a single tearing portion is preferable because the falsification display function can be clearly exhibited. The size and arrangement of the V-shaped slits can be adjusted as appropriate. However, the arrangement of the V-shaped slits closer to the center of the main surface than the peripheral portion of the main surface of the unit cell can further enhance the effect of preventing the generation of wrinkles. it can. Also, the number of slits can be adjusted as appropriate, and two or more slits may be provided at each extended end.

  The present invention can be said to be very useful for the purpose of producing a high-capacity, small-sized and light-weight battery pack at a low cost, for example, as a power source for a mobile phone or a PDA.

1 battery pack 2A, 2B unit cell (lithium ion polymer battery)
3 Case member 4 Protection circuit board 5 Board holder 6 Resin sheet 7 Exterior label 20A, 20B Second main surface (upper surface)
21A, 21B Top sealing part 22A, 22B Negative electrode tab 23A, 23B Positive electrode tab 24A, 24B Insulating paper 25A, 25B Breaker (PTC element)
26A, 26B, 27A, 27B Lead plate 28A, 28B First main surface (lower surface)
30A, 30B Cell storage part 31 Notch 32A, 32B, 33A, 33B Communication hole 40 Substrate body 41 Connector wiring 34A-34C, 35A, 35B Fitting claw (fitting part)
50 upper surface part 51 window part 52 collar part 53A-53C fitting groove (fitting part)
54A, 54B Engagement claw
70 Laminate layer (label layer)
71 Adhesive layer 72 Resin sheet layer 73 Adhesive layer
74A to 74D V-shaped slit 301 Substrate storage portion 302 to 308 Rib 410 Connector portion 540A, 540B Rear end portion 701 Exterior label main surface portion 702A to 702D, 702X Extension end portion

Claims (7)

A unit cell having a rectangular parallelepiped outer shape composed of rectangular first and second main surfaces and four side surfaces having a smaller area than the two main surfaces;
A circuit board electrically connected to at least one of a positive electrode side or a negative electrode side of the unit cell;
A frame-shaped unit cell storage unit that surrounds and stores the unit cell from the four side surfaces except the two main surfaces, and a circuit board that is supported from the bottom side and stored so as to be juxtaposed with the unit cell. A case member having a dish-shaped substrate storage portion,
A sheet member covering the first main surface of the unit cell stored in the unit cell storage unit;
An exterior label that is applied so as to cover at least the second main surface of the unit cell;
The main surface portion of the exterior label has a laminated structure including a label layer exposed to the outside and a resin sheet layer having rigidity higher than that of the label layer. The battery pack according to claim 1, wherein the resin sheet layer is made of polycarbonate. A plurality of extending end portions that extend from the periphery of the main surface portion and are attached to the first main surface of the unit cell;
The battery pack according to claim 1, wherein a V-shaped slit is formed in at least one of the extended end portions. The battery pack according to claim 3, wherein a position of a top portion of the V-shaped slit is provided in accordance with a position closer to a center from a peripheral edge of the sheet member. The battery pack according to any one of claims 1 to 4, wherein in the exterior label, the resin sheet layer is provided at a position excluding the extended end portion. The battery pack according to claim 1, wherein two or more of the unit cells are accommodated in the case member in a state of being arranged in parallel with each other. The battery pack according to claim 1, wherein the unit cell is a lithium ion polymer battery.

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