JP5183074B2 - Pack battery - Google Patents

Description

  The present invention relates to a battery pack in which a thin battery is housed in an outer case.

  Thin battery pack batteries are conveniently used by being mounted on various portable electric devices. In particular, it is an optimal shape for an electric device such as a mobile phone or PDA that needs to be thinned as a whole. Since thin battery packs can be mounted on various electrical devices, research has been conducted on how thin battery packs can be made. Currently, polymer batteries are being developed as extremely thin thin batteries. As a thin battery, a lithium ion secondary battery made of a metal outer can has been developed. A thin battery made of a lithium ion secondary battery that is currently being developed has already been made considerably thin. Furthermore, studies have been conducted to make these thin batteries thinner without reducing the charging capacity.

  In order to increase the capacity while reducing the thickness of these thin batteries, the thickness of the battery is reduced to increase the width, and the area of flat surfaces located on both sides facing each other is increased. The thin battery of this shape has a problem that as the number of charge / discharge cycles increases, the battery swells as the internal pressure increases, particularly, the swell on the flat surface increases. Such swelling of the thin battery increases as the energy density of the battery increases. For this reason, in a battery pack containing a thin battery, as the charge / discharge cycle elapses, the thin battery may increase due to an increase in internal pressure, and the entire battery pack may expand. Unfortunately, when the battery pack is mounted on the portable device body, if the thin battery expands greatly and the entire pack battery expands, there may be a problem that the battery pack cannot be removed from the main device. This problem can be solved by providing a gap for absorbing the swelling of the thin battery inside the case for housing the thin battery. However, if such a gap is provided inside the case, the thickness of the entire battery pack increases.

As a battery pack for solving such problems, a battery pack having an opening on the surface of a case has been developed. (See Patent Document 1)
The battery pack described in this publication is shown in an exploded perspective view in FIG. The battery pack includes a thin battery 92 and an outer case 91 that houses the thin battery 92. The thin battery 92 has a first flat surface 92A and a second flat surface 92B that are square and thinner than the width of the battery and are positioned on both sides facing each other. The outer case 91 includes a lower case 91A and an upper case 91B, and has an opening 94 that exposes the first flat surface 92A and the second flat surface 92B of the thin battery 92 and has the maximum area of the outer case 91. Each of the two surfaces (the bottom surface and the top surface in the figure) is provided with an opening at the center. In the illustrated battery pack, a thin battery 92 is housed in an exterior case 91 composed of a lower case 91 and a lower case 9, and then covered with an insulating material 93 for covering from the outside of the lower case 91B and the upper case 91A.
JP 2004-22234 A

  Since the battery pack of FIG. 1 has an opening at the center of the outer case, the opening plays a role of escape when the thin battery swells, and the thin battery passes through a charge / discharge cycle. Even when it swells, the expansion of the battery pack can be suppressed by absorbing the swelling of the thin battery at the opening. However, the battery pack with this structure is required to be mounted inside an electric device. This is because the thin battery cannot be housed in a case with sufficient strength. In particular, since this battery pack has an opening on the surface of the case, there is a drawback that the strength of the case provided with the opening is lowered and cannot be made sufficiently strong. Battery packs that do not have sufficient strength need to be built into electrical equipment, are susceptible to damage from manufacture to the user, and are easily damaged when the user removes them from the electrical equipment. There is.

  The present invention has been developed for the purpose of solving this drawback. A main object of the present invention is to provide a low-cost battery pack incorporating a thin battery capable of realizing sufficient strength while having a structure capable of absorbing the swelling of the battery through an opening provided on the surface of the case.

The battery pack of the present invention has the following configuration in order to achieve the aforementioned object.
The battery pack is a rectangular thin battery 2 whose thickness is smaller than the width of the battery. The battery core 13 is composed of a thin battery 2 having a first flat surface 2A and a second flat surface 2B on opposite surfaces. And an outer case 1 that houses the battery core 13. The outer case 1 is made of plastic, and includes a first case 1A having a first surface plate 1a that covers the first flat surface side of the thin battery 2, and a second surface plate 1b that covers the second flat surface side. It consists of 2nd case 1B which has. The first surface plate 1 a and the second surface plate 1 b are formed larger than the outer shape of the battery core 13. The first case 1A has an opening 4 that allows the first surface plate 1a to expose the first flat surface 2A of the thin battery 2 to the outside, and has an outer wall 8 along the outer periphery of the first surface plate 1a. Further, the reinforcing rib 6 is integrally formed by being connected to the inner surface of the outer peripheral portion 7 of the first surface plate 1 a and the outer wall 8. The second case 1B connects the outer peripheral edge of the second surface plate 1b to the outer wall 8 of the first case 1A. Further, the battery pack has an exterior sheet 3 attached so as to close the opening 4 of the first case 1A.

  In the battery pack of claim 2 of the present invention, in addition to the configuration of claim 1, the second case 1B has an outer wall 8 along the outer periphery of the second surface plate 1b, and this outer wall 8 is connected to the first case 1A. It is connected to the outer wall 8.

  In addition to the structure of claim 1, the battery pack of claim 3 of the present invention is formed by integrally molding the inner wall 5 facing the outside of the battery core 13 on the inner surface of the first surface plate 1a.

  In the battery pack of claim 4 of the present invention, in addition to the configuration of claim 3, the battery core 13 has a protective element 15 fixed to the outer peripheral surface of the thin battery 2, and the inner wall 5 of the first case 1A is this protection. It has a recess 5 </ b> B for accommodating the element 15.

  The battery pack of claim 5 of the present invention has the battery core 13 by connecting the circuit board 10 to the thin battery 2 via the lead plates 16 and 17 in addition to the structure of claim 1.

The battery pack according to claim 6 of the present invention has a battery core by connecting a circuit board to a thin battery via a lead plate in addition to the configuration of claim 3 , and the first case 1A is a lead plate 16 of the battery core 13. , 17 is provided in the inner wall 5 with slits 5A.

  The battery pack according to the present invention has a feature that a sufficient strength can be realized while having a structure in which an opening is provided on the surface of the case. This unique feature is that the battery pack of the present invention has a structure in which a battery core made of a thin battery is housed in a plastic outer case, and the outer case includes a first case having a first surface cover portion and a second surface. The first surface plate and the second surface plate are formed larger than the outer shape of the battery core, and the flat surface of the thin battery is exposed to the outside on the first surface plate. An opening is provided, an outer wall is provided along the outer periphery of the first surface plate, a reinforcing rib is provided so as to connect to the inner surface of the outer periphery of the first surface plate and the outer wall, and an opening is provided. Thus, the outer peripheral portion of the first surface plate whose strength is lowered is realized by a unique structure that is reinforced with the reinforcing rib.

  In particular, the battery pack of the present invention is characterized in that an outer wall and a reinforcing rib are integrally formed on the outer periphery of the first surface plate having an opening. The reinforcing rib formed integrally with the outer peripheral portion and the outer wall of the first surface plate reinforces the first surface plate whose strength is reduced by the opening on the outside thereof. Accordingly, the first case is reinforced at the outer peripheral portion thereof with the reinforcing rib provided at the outer peripheral portion of the first surface plate, while having a structure in which a large opening is provided in the surface plate of the first case. For this reason, the battery pack of the present invention can have a tough structure while having a structure in which an opening is provided in the first surface plate. The battery pack of the present invention that realizes excellent strength does not necessarily have to be built in the case of the electrical device as in the case of the battery pack shown in FIG. Can be installed in the state Further, the manufactured battery pack is not damaged before being sent to the user, and the battery pack is not damaged even when the user removes the battery pack from the electric device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows. Moreover, the member shown by the claim is not what specifies the member of embodiment. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  2 and 3 are perspective views of a battery pack according to an embodiment of the present invention, FIGS. 4 and 5 are exploded perspective views, and FIG. 6 is a perspective view of a first case.

  The battery pack shown in these drawings includes a battery core 13 made of a thin battery 2 and an outer case 1 that houses the thin battery 2. In the illustrated battery pack, the circuit board 10 is connected to the thin battery 2 to form a battery core 13, and the battery core 13 is housed in the outer case 1.

  The thin battery 2 is a secondary battery in which the thickness is thinner than the width and the outer periphery is substantially rectangular. As shown in FIG. 7, the thin battery 2 is a rectangular battery in which the thickness of the battery is thinner than the width, and the first flat surface 2 </ b> A and the second flat surface 2 </ b> B located on both sides facing each other, A terminal surface 2C for connecting the first flat surface 2A and the second flat surface 2B, on which the terminal group is arranged, an end surface 2D facing the terminal surface 2C, and a terminal surface 2C and the end surface 2D are connected to each other. It has six surfaces including one side surface 2E and a second side surface 2F.

  However, in this specification, the first side surface and the second side surface of the thin battery are surfaces located on both sides of the thin battery, and are a first flat surface, a second flat surface, a terminal surface, and an end surface. It means a surface that can be seen when viewed from a direction parallel to. Therefore, the first side surface and the second side surface do not necessarily have to be one plane, and may be curved surfaces, partially curved surfaces, or a combination of a plurality of planes. You can also

  The thin battery 2 is a lithium ion battery or a polymer battery. The polymer battery is a lithium polymer battery. However, the present invention does not specify the thin battery 2 as a lithium ion battery or a polymer battery. The thin battery may be a battery other than these batteries, for example, a nickel hydrogen battery or a nickel cadmium battery.

  The outer case 1 is manufactured by integrally molding the whole with plastic. As the plastic, a plastic in which fibers such as glass fiber and carbon fiber are embedded and reinforced, for example, PPS (polyphenylene sulfite) is suitable. PPS has extremely excellent strength. PPS can be reinforced with fibers to improve impact strength. Furthermore, since PPS is excellent in flame retardancy, for example, when PPS is used as the material of the exterior case, even if the plate thickness is reduced to 0.4 mm, the flame retardancy defined by the UL standard etc. Can meet the criteria. Therefore, PPS can make the outer case thinner while maintaining flame retardancy, and accordingly, downsizing of the battery pack can be achieved. However, plastic such as polycarbonate can be used as the plastic of the outer case, and therefore the plastic is not specified as PPS.

  The thin battery 2 is assembled in the state of the battery core 13 and stored in the outer case 1. The battery core 13 connects the circuit board 10 to the thin battery 2 via lead plates 16 and 17. In the illustrated battery pack, two thin batteries 2 are arranged in parallel on the same surface and housed in an outer case 1. Adjacent thin batteries 2 are connected in parallel by lead plates 16 and 17. Lead plates 16 and 17 for connecting the thin battery 2 are connected to the circuit board 10. This battery pack connects a plurality of thin batteries 2 in parallel. However, the battery pack of the present invention can be housed in an exterior case by connecting a plurality of thin batteries in parallel or in series.

  Further, the battery core 13 shown in the figure is connected to the circuit board 10 via the protective element 15. The protection element 15 is an element that cuts off the current when an overcurrent flows through the thin battery 2 or cuts off the current when the thin battery 2 is heated to an abnormal temperature, and is a fuse, a PTC, or the like. In the battery pack, the protective element 15 is opposed to the outer peripheral surface of the thin battery 2, and the protective element 15 is disposed on the end face 2 </ b> D of the thin battery 2 in FIGS. 4 and 5. Further, the protection element 15 is disposed at a boundary portion between the adjacent thin batteries 2. The protection element 15 is disposed so as to protrude from the end surface 2D. The protective element 15 has connection leads 18 connected to both ends, and these connection leads 18 are connected to the thin battery 2 and the circuit board 10 via the lead plate 16, respectively. One connection lead 18 of the protection element 15 is connected to a lead plate 16B connected to the end face 2D of the thin battery 2 via a lead plate 16C. The other connection lead 18 of the protection element 15 is connected to the circuit board 10 via a lead plate 16A.

  The circuit board 10 has an output terminal 9 fixed on the surface. The output terminal 9 is exposed to the outside from the electrode window 14 provided in the exterior case 1. The circuit board 10 is mounted with a battery protection circuit (not shown). The protection circuit is a circuit that protects the overcurrent of the thin battery 2 or a circuit that prevents the thin battery 2 from being overcharged or discharged.

  The battery core 13 connects both ends of the circuit board 10 to the positive and negative electrodes of the thin battery 2 via lead plates 16 and 17. The circuit board 10 is connected with being separated from the thin battery 2 through the lead plates 16 and 17. The circuit board 10 is connected to a fixed position of the first case 1A with an insertion structure. In the first case 1A shown in FIGS. 4 and 6, the inner surface of the first surface plate 1a is formed into a shape in which the circuit board 10 is fitted and placed in a fixed position. However, the battery pack can also hold the circuit board in place via the board holder. In this battery pack, a circuit board is connected to a fixed position of the first case 1A through a board holder with a fitting structure.

  The illustrated first case 1A has an inner wall 5 on the inner surface of the first surface plate 1a. In the first case 1 </ b> A, the inner wall 5 is disposed between the thin battery 2 and the circuit board 10. The inner wall 5 disposed between the thin battery 2 and the circuit board 10 is provided with a plurality of reinforcing ribs 6 on the outer side, and the circuit board 10 is arranged in a fixed position with a fitting structure. The inner wall 5 at the boundary between the thin battery 2 and the circuit board 10 is provided with slits 5 </ b> A through which lead plates 16 and 17 connecting the thin battery 2 and the circuit board 10 pass. In this structure, the thin battery 2 and the circuit board 10 are insulated by the inner wall 5 and arranged at a fixed position.

  The outer case 1 covers a first case 1A having a first surface plate 1a that covers a first flat surface 2A of the thin battery 2 (the lower surface of the thin battery 2 in FIG. 4), and a second flat surface 2B. It consists of the 2nd case 1B which has the 2nd surface plate 1b. The first case 1A and the second case 1B are integrally formed of the aforementioned plastic as a whole. The first case 1 </ b> A and the second case 1 </ b> B have the same outer shape, are connected to the outer periphery, and store the battery core 13 of the thin battery 2 therein. Furthermore, the outer shape of the first surface plate 1 a and the second surface plate 1 b is larger than the outer shape of the battery core 13. In the outer case 1 of FIG. 6, the widths of the outer peripheral portions 7 on both sides in FIG. 6 and the outer peripheral portion 7 on which the circuit board 10 is disposed are widened. A protection element 15 for the battery core 13 is disposed on the inner surface of the wide outer peripheral portion 7. Although not shown in the drawings, the battery pack of the present invention can have a wider outer peripheral portion along the entire circumference of the first surface plate and the second surface plate.

  In the first case 1A, an opening 4 is provided in the first surface plate 1a to expose the first flat surface 2A of the thin battery 2 to the outside. Since the battery packs of FIGS. 4 and 5 house the battery core 13 composed of two thin batteries 2, the first flat surface 2A of each thin battery 2 is exposed to the outside on the first surface plate 1a. Two openings 4 are provided. According to this structure, since the two openings 4 can be connected, the strength of the first case 1A can be improved. However, the battery pack of the present invention can be provided with one opening on the first surface plate, and a plurality of thin batteries can be exposed to the outside through this opening. The opening 4 exposes the first flat surface 2A of the thin battery 2 to the outside, and causes the flat surface of the thin battery 2 to bulge out from the opening. The thin battery 2 has a small swelling at the outer peripheral portion of the flat surface, and the middle portion tends to swell. Therefore, the opening 4 is large enough to expose the portion excluding the outer peripheral portion of the first flat surface 2A to the outside, for example, 60% to the total area of the flat surface excluding the outer peripheral portion of the first flat surface 2A. 95% is opened to the outside.

  The strength of the first surface plate 1 a is reduced by providing the opening 4. The first surface plate 1 a whose strength has been reduced at the opening 4 is reinforced by the reinforcing rib 6 provided on the outer peripheral portion 7. Therefore, the first surface plate 1a is provided with the outer wall 8 along the outer periphery, and further integrally formed with the reinforcing rib 6 so as to be connected to the outer wall 8 and the inner surface of the outer peripheral portion 7. The reinforcing rib 6 is disposed outside the battery core 13 so as not to interfere with the storage of the battery core 13. The first surface plate 1 a shown in FIG. 6 is provided with a plurality of reinforcing ribs 6 on the inner surface of the outer peripheral portion 7 on both sides of the battery core 13. In the illustrated embodiment, five rows of reinforcing ribs 6 are integrally formed and provided. Five rows of reinforcing ribs 6 are integrally formed on the upper outer peripheral portion 7 and the lower outer peripheral portion 7 of the battery core 13. Further, the first surface plate 1 a shown in FIG. 6 is provided with the inner wall 5 on the inner side of the reinforcing rib 6 and on the outer side of the battery core 13. In the first case 1A, the battery core 13 can be fitted in the inner wall 5 and the battery core 13 can be arranged at a fixed position. In addition, the battery core 13 can be arranged with the inner wall 5 so as not to be displaced to a fixed position of the first case 1A.

  In the first case 1A of FIG. 6, the inner wall 5 is provided with a recess 5B that houses the protection element 15, and the protection element 15 of the battery core 13 is disposed in the recess 5B. With this structure, the battery core 13 can be securely placed at a fixed position in the case while protecting the protective element 15 with the inner wall 5.

  The second case 1B is provided with an outer wall 8 along the outer periphery. The outer wall 8 of the second case 1B is connected to the outer wall 8 of the first case 1A by a method such as ultrasonic welding, and the battery core 13 is housed inside the first case 1A and the second case 1B. In the second case 1 </ b> B shown in FIG. 5, the outer wall 8 provided at the outer edge of the outer peripheral portion 7 that houses the circuit board 10 is raised. In the first case 1 </ b> A, the outer wall 8 of the portion excluding the outer edge of the outer peripheral portion 7 that houses the circuit board 10 is raised.

  With the battery core 13 in the outer case 1, the outer sheet 3 made of an insulating sheet such as a label is attached to close the opening 4 of the first surface plate 1a. The exterior sheet 3 is bonded to the first flat surface 2A of the thin battery 2 and the first surface plate 1a. The exterior sheet 3 is an insulating sheet made of a flexible plastic sheet or label. The exterior sheet 3 is adhered to the thin battery 2 and the exterior case 1 via an adhesive, or is adhered via an adhesive layer.

It is a disassembled perspective view which shows the conventional battery pack. 1 is a perspective view of a battery pack according to an embodiment of the present invention. It is the perspective view which turned the battery pack shown in FIG. 2 upside down. It is a disassembled perspective view of the battery pack shown in FIG. FIG. 4 is an exploded perspective view of the battery pack shown in FIG. 3. It is an expansion perspective view of the 1st case. It is a disassembled perspective view of a battery core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exterior case 1A ... 1st case 1a ... 1st surface plate
DESCRIPTION OF SYMBOLS 1B ... 2nd case 1b ... 2nd surface plate 2 ... Thin battery 2A ... 1st flat surface 2B ... 2nd flat surface
2C ... Terminal surface 2D ... End surface
2E ... 1st side surface 2F ... 2nd side surface 3 ... Exterior sheet 4 ... Opening part 5 ... Inner wall 5A ... Slit 5B ... Recessed part 6 ... Reinforcement rib 7 ... Outer peripheral part 8 ... Outer wall 9 ... Output terminal 10 ... Circuit board 13 ... Battery core 14 ... Electrode window 15 ... Protection element 16 ... Lead plate 16A ... Lead plate 16B ... Lead plate
16C ... Lead plate 17 ... Lead plate 18 ... Connection lead 91 ... Exterior case 91A ... Lower case
91B ... Upper case 92 ... Thin battery 92A ... First flat surface 92B ... Second flat surface 93 ... Insulating sheet 94 ... Opening

Claims (6)

A rectangular thin battery whose thickness is less than its width, a battery core comprising a thin battery having a first flat surface and a second flat surface on both sides facing each other, and an exterior housing the battery core A battery pack including a case, wherein the outer case is made of plastic, and has a first surface plate that covers a first flat surface side of the thin battery, and a second flat surface side A second case having a second surface plate covering the first surface plate, wherein the first surface plate and the second surface plate are formed larger than the outer shape of the battery core,
The first case has an opening in the first surface plate for exposing the flat surface of the thin battery to the outside, an outer wall along the outer periphery of the first surface plate, and the outer periphery of the first surface plate. Reinforcing ribs are integrally formed and connected to the inner surface of this part and this outer wall,
The second case is a battery pack in which the outer peripheral edge of the second surface plate is connected to the outer wall of the first case, and an exterior sheet is attached so as to close the opening of the first case. The battery pack according to claim 1,
A battery pack, wherein the second case has an outer wall along the outer periphery of the second surface plate, and the outer wall is connected to the outer wall of the first case. The battery pack according to claim 1,
A battery pack characterized in that an inner wall facing the outer side of the battery core is integrally formed on the inner surface of the first surface plate. The battery pack according to claim 3,
A battery pack in which a battery core fixes a protective element to an outer peripheral surface of a thin battery, and an inner wall of a first case has a recess for storing the protective element. The battery pack according to claim 1,
A battery pack characterized in that a circuit board is connected to a thin battery via a lead plate to form a battery core. The battery pack according to claim 3,
A battery core by connecting the circuit board through the lead plate to the thin battery, pack batteries that the first case is characterized in that is provided on the inner wall of the slit for passing the lead plates of the battery core.

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