WO2021070754A1 - Battery pack and electronic device - Google Patents

Abstract

A battery pack which comprises a cylindrical outer package tube, a wiring part and a cylindrical battery cell that is provided with film-like outer package material, wherein: external terminals are provided on both ends of the outer package tube; the battery cell has a thermal fusion bonding part on the lateral circumferential surface; and the wiring part is arranged on a region of the lateral circumferential surface, said region not overlapping with the thermal fusion bonding part. Figure 11

Description

Battery packs and electronics

The present invention relates to a battery pack and an electronic device.

Cylindrical non-aqueous electrolyte secondary batteries (for example, lithium ion secondary batteries) are used as a power supply source for various devices such as power tools and wearable devices. For example, Patent Document 1 describes a battery pack having a configuration in which a top cover, a protective circuit board, a cylindrical cell, and a bottom cover are covered with a label.

U.S. Pat. No. 8415038

However, the battery pack described in Patent Document 1 has a problem that it is difficult to miniaturize the battery pack and the volumetric energy density is lowered. Specifically, since the wiring that connects the protection circuit board (PCM (Protection Circuit Module)) and the external terminal is arranged along the side surface of the cylindrical cell, the outer diameter of the battery pack is the wiring. The size increases by the thickness. Moreover, since the external terminal and the cap are separate parts, an extra clearance is created between the parts. Further, since the board portion of the PCM is composed of a printed wiring board and the printed wiring board generally has a thickness of 0.7 to 1.0 mm, a large amount of board space is required. Further, since the PCM and the wiring portion are separate parts, a space for connecting the PCM and the wiring portion is required. From the above viewpoint, there is a problem that it becomes difficult to miniaturize the battery pack and the volumetric energy density decreases.

In view of this point, one of the objects of the present invention is to provide a battery pack capable of miniaturization and suppressing a decrease in volumetric energy density, and an electronic device to which the battery pack is applied.

In order to solve the above-mentioned problems, the present invention
It has a cylindrical exterior tube, a wiring portion, and a cylindrical battery cell provided with a film-shaped exterior material.
External terminals are provided at both ends of the outer tube,
The battery cell has a heat-sealing portion on the side peripheral surface,
This is a battery pack in which the wiring section is located on the side peripheral surface so that it does not overlap with the heat fusion section.
Further, the present invention may be an electronic device having the above-mentioned battery pack.

According to the present invention, it is possible to reduce the size of the battery pack and suppress a decrease in the volumetric energy density of the battery pack. It should be noted that the contents of the present invention are not limitedly interpreted by the effects exemplified in the present specification.

FIG. 1 is a perspective view of the battery pack according to the embodiment. FIG. 2 is an exploded perspective view of the battery pack according to the embodiment. FIG. 3 is a perspective view showing the assembly of the battery pack according to the embodiment. FIG. 4 is a diagram referred to when explaining a configuration example of the battery cell according to the embodiment. FIG. 5 is a diagram referred to when explaining a configuration example of the battery cell according to the embodiment. FIG. 6 is a diagram referred to when explaining a configuration example of the battery cell according to the embodiment. FIG. 7 is a diagram referred to when explaining a configuration example of the positive electrode side external terminal according to the embodiment. 8A and 8B are diagrams referred to when explaining a configuration example of the positive electrode side external terminal according to the embodiment. 9A and 9B are diagrams referred to when explaining a connection configuration example of the battery cell, the circuit board, and the positive electrode side external terminal according to the embodiment. FIG. 10 is a diagram showing an example of a circuit configuration of the battery pack according to the embodiment. 11A and 11B are diagrams referred to when describing the first feature of the battery pack according to the embodiment. FIG. 12 is a diagram referred to when explaining the first feature of the battery pack according to the embodiment. FIG. 13 is a diagram referred to when explaining the second feature of the battery pack according to the embodiment. FIG. 14 is a diagram referred to when explaining the second feature of the battery pack according to the embodiment. 15A and 15B are diagrams for explaining a modification. 16A to 16F are diagrams for explaining a modified example. FIG. 17 is a diagram for explaining an application example of the battery pack according to the embodiment. FIG. 18 is a diagram for explaining an application example of the battery pack according to the embodiment.

Hereinafter, embodiments and the like of the present invention will be described with reference to the drawings. The explanation will be given in the following order.
<One Embodiment>
<Modification example>
<Application example>
The embodiments and the like described below are suitable specific examples of the present invention, and the contents of the present invention are not limited to these embodiments and the like.
Unless otherwise specified, the dimensions, materials, shapes, relative arrangements thereof, directions such as up, down, left, and right of the constituent members described in the embodiments and the like are the scope of the present invention. It is not intended to be limited to just, but merely an example of explanation. The size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation, and only a part of the reference reference numerals is used to prevent the illustration from becoming complicated. It may be illustrated or the illustration may be simplified. Further, in the following description, members having the same or the same quality are shown with the same name and reference numeral, and duplicate description will be omitted as appropriate. Further, each element constituting the present invention may be configured such that a plurality of elements are composed of the same member and the plurality of elements are combined with one member, or conversely, the function of one member is performed by the plurality of members. It can also be shared and realized.

<One Embodiment>
[Battery pack configuration example]
(Overall configuration example)
First, with reference to FIGS. 1 to 3, an example of the overall configuration of the battery pack (battery pack 1) according to the present embodiment will be described. FIG. 1 is a perspective view of the battery pack 1. FIG. 2 is an exploded perspective view of the battery pack 1. FIG. 3 is a perspective view of a configuration (appropriately referred to as Assy 8) excluding the outer tube of the battery pack 1.

As shown in FIG. 1, the battery pack 1 has a substantially cylindrical shape. The battery pack 1 is, for example, a lithium ion secondary battery that can be used like a dry battery.

As shown in FIG. 2, the battery pack 1 includes a battery cell 2, a cylindrical outer tube 3, a circuit board 4, an insulating tape 5, and a pair of external terminals (caps) provided at both ends of the outer tube 3. It has a positive electrode side external terminal 6 and a cap-shaped negative electrode side external terminal 7). The battery cell 2 is, for example, a cylindrical battery cell having a laminated shape (with a laminated film on the outside), and has a positive electrode terminal 21 and a negative electrode terminal 22. The details of the battery cell 2 will be described later.

The outer tube 3 internally houses the configuration of the battery pack 1 over the assembly 8. The positive electrode side external terminal 6 and the negative electrode side external terminal 7 are press-fitted into both ends of the outer tube 3, respectively. The outer tube 3 is formed of, for example, stainless steel, nickel, aluminum, each metal simple substance, or an alloy material thereof. The outer tube 3 is not limited to a metal outer case, and is a single resin of polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and acrylonitrile-butadiene-styrene copolymer resin (ABS). Alternatively, the outer case may be molded from a material such as these two types of alloy resin or blended resin.

The circuit board 4 is composed of a flexible printed circuit board (FPC (Flexible Printed Circuits)). Since the circuit board 4 is composed of the FPC, the thickness of the circuit board 4 can be reduced. The circuit board 4 has a connecting circuit board 41, a positive electrode side circuit board 42, and a negative electrode side circuit board 43. The positive electrode side circuit board 42 and the negative electrode side circuit board 43 are connected by a connecting circuit board 41. As described above, the connecting circuit board 41, the positive electrode side circuit board 42, and the negative electrode side circuit board 43 are integrally formed, whereby the manufacturing process can be simplified. In the present embodiment, the connecting circuit board 41 corresponds to the first circuit board, and the positive electrode side circuit board 42 and the negative electrode side circuit board 43 correspond to the second circuit board.

The connecting circuit board 41 has a thin plate-like shape and extends in the same direction as the longitudinal direction of the battery pack 1. Although details will be described later, the battery cell 2 has a heat-sealing portion on the side peripheral surface, and the wiring portion is arranged in a range of the side peripheral surface that does not overlap with the heat-sealing portion. In the present embodiment, the wiring portion is the first circuit board composed of the circuit board, but it may be a wiring board or a lead wire instead of the circuit board.

The positive electrode side circuit board 42 (a part of the circuit board 4) is a thin plate extending in a direction substantially orthogonal to the extending direction of the connecting circuit board 41. The positive electrode side circuit board 42 is bent so as to form an appropriate number of layers (also referred to as zigzag folding). With such a configuration, an extra length can be secured for the positive electrode side circuit board 42, and it is possible to prevent the positive electrode side circuit board 42 from being cut due to an impact. A reinforcing plate 42B is provided on the outermost surface 42A of the positive electrode side circuit board 42. As the reinforcing plate 42B, a resin or a film can be applied. The positive electrode side circuit board 42 is arranged between the battery cell 2 and the positive electrode side external terminal 6 inside the outer tube 3.

The negative electrode side circuit board 43 (a part of the circuit board 4) is a thin plate extending in a direction substantially orthogonal to the extending direction of the connecting circuit board 41. The negative electrode side circuit board 43 is bent so as to form an appropriate number of layers. With such a configuration, an extra length can be secured for the negative electrode side circuit board 43, and it is possible to prevent the negative electrode side circuit board 43 from being cut due to an impact. For example, the protection circuit 43A is provided between the layers of the negative electrode side circuit board 43 or on the innermost surface of the negative electrode side circuit board 43. The protection circuit 43A is a circuit that performs a known protection operation to prevent overcurrent, overdischarge, and the like of the battery pack 1. The negative electrode side circuit board 43 is arranged between the battery cell 2 and the negative electrode side external terminal 7 inside the outer tube 3.

The positive electrode side circuit board 42 of the circuit board 4 is welded to the positive electrode terminal 21 of the battery cell 2. Further, the negative electrode side circuit board 43 of the circuit board 4 is welded to the negative electrode terminal 22 of the battery cell 2. As a result, the battery cell 2 and the protection circuit 43A are electrically connected. Then, the insulating tape 5 is wound around the battery cell 2 integrated by welding and the circuit board 4 (specifically, the connecting circuit board 41) to form the assembly 8 (see FIG. 3). .. By wrapping the battery cell 2 and the circuit board 4 with the insulating tape 5, the outer tube 3 becomes polar, and a short circuit occurs between the outer tube 3 and the positive electrode side external terminal 6 and the negative electrode side external terminal 7. This can be prevented and the safety of the battery pack 1 can be improved. Further, by wrapping the battery cell 2 and the circuit board 4 with the insulating tape 5, it is possible to prevent the circuit board 4 from being disconnected.

The positive electrode side external terminal 6 has a circular positive electrode side conductive portion 61 made of metal and a circular positive electrode side insulating portion 62 provided so as to surround the positive electrode side conductive portion 61. The positive electrode side insulating portion 62 is formed of, for example, a resin. The positive electrode side insulating portion 62 has a resin positive electrode side flange portion 63 erected from the vicinity of the peripheral edge portion on the inner surface (main surface on the side facing the inside of the outer tube 3) of the positive electrode side insulating portion 62. .. The positive electrode side external terminal 6 is press-fitted into the outer tube 3 by inserting the positive electrode side flange portion 63 into the outer tube 3. The positive electrode side conductive portion 61 is welded to the positive electrode side circuit board 42 of the circuit board 4.

The negative electrode side external terminal 7 has a circular negative electrode side conductive portion 71 made of metal and a circular negative electrode side insulating portion 72 provided so as to surround the negative electrode side conductive portion 71. The negative electrode side insulating portion 72 is formed of, for example, a resin. The negative electrode side insulating portion 72 has a resin negative electrode side flange portion 73 erected from the vicinity of the peripheral edge portion on the inner surface of the negative electrode side insulating portion 72 (the main surface on the side facing the inside of the outer tube 3). .. The negative electrode side external terminal 7 is press-fitted into the outer tube 3 by inserting the negative electrode side flange portion 73 into the outer tube 3. As a result, the positive electrode side external terminal 6 and the negative electrode side external terminal 7, that is, the external terminal are provided at both ends of the outer tube 3. The negative electrode side conductive portion 71 is connected to the negative electrode side circuit board 43 of the circuit board 4. The details of the positive electrode side external terminal 6 and the negative electrode side external terminal 7 will be described later.

(Battery cell)
Subsequently, the battery cell 2 according to the present embodiment will be described with reference to FIGS. 4 to 6. The battery cell 2 is provided on three sides of the substantially cylindrical accommodating portion 201 for accommodating the substantially cylindrical wound electrode body (not shown) and the peripheral portion 201 except for the folded portion 220 on the peripheral surface side. It includes a film-like exterior material 230 (specifically, a laminated film) having the provided sealing portions 202, 203, and 204, and a positive electrode lead and a negative electrode lead connected to the electrode body. The positive electrode lead corresponds to the positive electrode terminal 21 described above, and the negative electrode lead corresponds to the negative electrode terminal 22 described above.

The exterior material 230 has plasticity. The exterior material 230 is a so-called laminated film, and includes a metal layer, a surface protective layer provided on one surface of the metal layer, and a heat-sealing layer provided on the other surface of the metal layer. If necessary, the exterior material 230 may further include an adhesive layer between the surface protective layer and the metal layer, and one or both between the heat-sealing layer and the metal layer. Of both sides of the exterior material 230, the surface on the surface protective layer side is the outer surface (“outer surface of the exterior material 230”), and the surface on the heat fusion layer side is the inner surface (““ outer surface”) for accommodating the electrode body. The inner surface of the exterior material 230 ").

The metal layer plays a role of preventing the ingress of moisture and protecting the electrode body which is a stored object. As the material of the metal layer, for example, a metal foil made of aluminum or an aluminum alloy is used. As the material of the surface protective layer, for example, nylon or polyethylene terephthalate is used from the viewpoint of toughness and flexibility. As the material of the heat-sealing layer, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene or modified polypropylene is used from the viewpoint of flexibility and suppression of ingress of moisture and the like. As the material of the adhesive layer, for example, an acrylic adhesive, a polyester adhesive, a polyurethane adhesive, or the like is used. The exterior material 230 may further include a colored layer from the viewpoint of aesthetic appearance, or may contain a coloring material in at least one layer of a surface protective layer, a heat fusion layer, and an adhesive layer. .. As a specific example of the exterior material 230, the exterior material described in International Publication 2017/119486 can be applied.

The seal portions 202 and 203 are provided on both end faces of the accommodating portion 201, and the seal portions 204 are provided on the peripheral surface side of the accommodating portion 201. As shown in FIG. 5, the exterior material 230 includes two substantially cylindrical accommodating portions 201A and 201B having different depths, which are extended in the same direction and arranged in a direction orthogonal to the extending direction. It has peripheral portions 251, 252, and 253 provided on three sides of both end faces and peripheral surfaces (side surfaces) of the accommodating portions 201A and 201B. The exterior material 230 is folded back at the folded-back portion 220 between the adjacent accommodating portions 201A and 201B, and the peripheral portions 251, 252 and 253 of the accommodating portions 201A and 201B are overlapped with each other, and the accommodating portions 201A and 201B are combined. There is. The overlapped peripheral edges 251, 252, and 253 are sealed by heat fusion or the like, respectively, to form the sealing portions 202, 203, and 204, respectively. A substantially columnar accommodating portion 201 is formed by the combined substantially cylindrical accommodating portions 201A and 201B.

One end of the positive electrode terminal 21 is electrically connected to the positive electrode of the electrode body, and the other end of the positive electrode terminal 21 is led out to the outside of the exterior material 230 via the seal portion 202. Further, one end of the negative electrode terminal 22 is electrically connected to the negative electrode of the electrode body, and the other end of the negative electrode terminal 22 is led out to the outside of the exterior material 230 via the sealing portion 203. It is preferable that a sealant material 210 such as a heat-sealing material is provided between the positive electrode terminal 21 and the exterior material 230. Further, it is preferable that a sealant material 211 such as a heat-sealing material is also provided between the negative electrode terminal 22 and the exterior material 230. Thereby, the adhesiveness between the positive electrode terminal 21 and the negative electrode terminal 22 derived from the exterior material 230 and the inner surface of the exterior material 230 can be improved.

The exterior material 230 is formed by, for example, a deep drawing device. In the present embodiment, after being sealed by heat fusion or the like, the appropriately cut seal portion 204 is bent along the peripheral surface of the accommodating portion 201 as shown in FIG. Then, the bent seal portion 204 is attached and fixed to the peripheral surface of the accommodating portion 201 by heat fusion or the like. By bending the seal portion 204 in this way, the peripheral surface of the battery cell 2 can be made into a shape closer to a columnar shape, and the entire battery pack 1 can be miniaturized. The bent and heat-sealed portion of the seal portion 204 corresponds to the heat-sealed portion (hereinafter, appropriately referred to as the heat-sealed portion 240). The thickness of the connection circuit board 41 described above is set to be the same as the thickness of the heat-sealing portion 240 or thinner than the thickness of the heat-sealing portion 240.

The positive electrode terminal 21 and the negative electrode terminal 22 are preferably bent in a U shape along the end face of the electrode body (see FIG. 2). This is because the volumetric efficiency of the accommodating portion 201 can be increased. The positive electrode terminal 21 and the negative electrode terminal 22 are each made of a metal material such as aluminum, copper, nickel, or stainless steel, and have a shape such as a thin plate or a stitch. The sealant materials 210 and 211 are each made of a material having adhesion to the positive electrode terminal 21 and the negative electrode terminal 22, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene or modified polypropylene.

The electrode body accommodated in the accommodating portion 201 has a positive electrode, a negative electrode, and a separator having a long rectangular shape, respectively, and has a winding structure in which the positive electrode and the negative electrode are wound in the longitudinal direction via the separator. have. The positive electrode is provided with, for example, a metal foil such as aluminum as a positive electrode current collector, and a positive electrode active material layer having a positive electrode active material on both sides thereof. The negative electrode is provided with, for example, a metal foil such as copper as a negative electrode current collector, and a negative electrode active material layer having a negative electrode active material on both sides thereof. Nickel, stainless steel, or the like can also be used as the material of the positive electrode current collector and the negative electrode current collector.

The positive electrode active material is a positive electrode material capable of occluding and releasing lithium, and for example, a lithium-containing compound such as a lithium oxide, a lithium phosphorus oxide, a lithium sulfide, or an interlayer compound containing lithium is suitable. Two or more of these may be mixed and used. In order to increase the energy density, a lithium-containing compound having lithium, a transition metal element and oxygen is preferable. Examples of such a lithium-containing compound include a lithium composite transition metal oxide having a layered rock salt type structure, a lithium composite phosphate having an olivine type structure, and the like. The lithium-containing compound preferably contains at least one of the group consisting of cobalt, nickel, manganese, or iron as a transition metal element. Other positive electrode materials capable of occluding and releasing lithium include lithium-free inorganic compounds such as _{MnO 2} , V ₂ O ₅ , V ₆ O _{13, NiS, and MoS.}

The negative electrode activated carbon is a negative electrode material capable of storing and releasing lithium, and is, for example, non-graphitizable carbon, easily graphitizable carbon, graphite, thermally decomposed carbons, cokes, glassy carbons, and organic materials. Examples thereof include a calcined polymer compound, carbon fiber, and a carbon material such as activated carbon. As the graphite, it is preferable to use natural graphite that has been subjected to a spheroidizing treatment or the like, or substantially spherical artificial graphite. As the artificial graphite, artificial graphite obtained by graphitizing mesocarbon microbeads (MCMB), artificial graphite obtained by graphitizing or crushing a coke raw material, and the like are preferable. Coke includes pitch coke, needle coke, petroleum coke and the like. The calcined organic polymer compound refers to a polymer material such as phenol resin or furan resin that is calcined at an appropriate temperature to be carbonized, and partly made into graphitizable carbon or graphitizable carbon. Some are classified. Examples of this polymer material include polyacetylene and polypyrrole. These carbon materials are preferable because the change in crystal structure that occurs during charging / discharging is very small, a high charging / discharging capacity can be obtained, and good cycle characteristics can be obtained.

The separator allows lithium ions to pass through while preventing a short circuit of current due to contact between the positive and negative electrodes. For example, a porous synthetic resin made of polyethylene, polypropylene, polytetrafluoroethylene, a mixture or a copolymer thereof, or the like. It is a quality film or a porous film made of ceramic, and may be a laminate of two or more of these porous films. Among them, the porous membrane made of polyolefin is preferable because it has an excellent short-circuit prevention effect and the safety of the battery can be improved by the shutdown effect at high temperature, and the porous membrane made of polyethylene is particularly preferable.

The electrode body contains a non-aqueous electrolyte solution. An electrolyte layer containing a non-aqueous electrolytic solution and a polymer compound holding the non-aqueous electrolytic solution may be provided between the positive and negative electrodes together with the separator. In this case, the electrolyte layer may be used instead of the separator, and the separator may not be provided. The non-aqueous electrolyte solution contains a solvent and an electrolyte salt. In addition, in order to improve the battery characteristics, the non-aqueous electrolytic solution may further contain a known additive.

(External terminal on the positive electrode side)
Subsequently, with reference to FIGS. 7 and 8, a configuration example of the positive electrode side external terminal 6 according to the present embodiment will be described. Unless otherwise specified, the negative electrode side external terminal 7 has the same configuration as the positive electrode side external terminal 6 in the present embodiment. Of course, there may be slight differences such as differences in polarity marks.

FIG. 7 is a diagram showing a positive electrode side external terminal 6 in a state of being press-fitted into one open end of the outer tube 3. As described above, the positive electrode side insulating portion 62 is provided around the positive electrode side conductive portion 61. A mark 65 indicating polarity (plus) is formed at a predetermined position on the outer surface (main surface on the side exposed to the outside) 601A of the positive electrode side insulating portion 62.

FIG. 8A is a perspective view of the positive electrode side external terminal 6 viewed from the inside, and FIG. 8B is a view showing a cross section when the positive electrode side external terminal 6 is cut along the cutting line AA in FIG. 8A. As shown in FIG. 8A, the positive electrode side flange portion 63 is erected from the vicinity of the peripheral edge portion of the inner surface 601B of the positive electrode side insulating portion 62. The positive electrode side flange portion 63 generally has a ring shape, but in the present embodiment, cutout portions 63A and 63B, which are portions where the positive electrode side flange portion 63 does not exist, are formed. There is. The cutout portions 63A and 63B extend in a direction parallel to the longitudinal direction of the outer tube 3 in a state where the positive electrode side external terminal 6 is press-fitted into the outer tube 3. Since the cutout portions 63A and 63B are formed, the positive electrode side flange portion 63 is easily deformed, and the positive electrode side external terminal 6 can be easily press-fitted into the outer tube 3. Further, since the welded area between the positive electrode tab 620 and the positive electrode side circuit board 42 can be increased by the cutout portions 63A and 63B, stronger bonding becomes possible.

A part of the thin plate-shaped positive electrode tab 620 is erected from the vicinity of the end of the inner surface 601B of the positive electrode side external terminal 6. Further, as shown in FIG. 8B, a part of the positive electrode tab 620 is arranged in the positive electrode side insulating portion 62 and is connected to the positive electrode side conductive portion 61. For example, after the positive electrode side conductive portion 61 and the positive electrode tab 620 are welded together, the positive electrode side insulating portion 62 is formed by molding or the like. The positive electrode tab 620 and the positive electrode side conductive portion 61 may be an integral conductor.

U-shaped notches 621A and 621B are formed at appropriate positions of the exposed portion of the positive electrode tab 620, for example, at the opposite side portions (see FIG. 8A). Since the cutout portions 621A and 621B are formed, the positive electrode tab 620 can be easily bent in an appropriate direction. The positive electrode tab 620 bent in an appropriate direction and the positive electrode side circuit board 42 of the circuit board 4 are connected by welding.

As shown in FIG. 8B, a part of the inside of the positive electrode side conductive portion 61 (including the portion of the positive electrode tab 620 welded to the positive electrode side conductive portion 61), specifically, the positive electrode side conductive portion 61 (positive electrode side). A part of the positive electrode side insulating portion 62 is interposed between the positive electrode tab 620 portion welded to the conductive portion 61) and the inner surface 601B of the positive electrode side insulating portion 62. A part of the positive electrode side insulating portion 62 functions as a reinforcing portion 630.

It is necessary to prevent damage to the positive electrode side conductive portion 61 and protect the positive electrode side conductive portion 61 when the battery pack 1 is dropped or the like. Therefore, in the present embodiment, as shown in FIG. 8B, the outer end surface of the positive electrode side conductive portion 61 is provided so as to be recessed inward from the outer end surface of the positive electrode side insulating portion 62, that is, the outer surface 601A of the positive electrode side insulating portion 62. In this way, the positive electrode side external terminal 6 is formed.

As in the present embodiment, the positive electrode side external terminal 6 has a configuration in which the positive electrode side conductive portion 61 and the cap-shaped positive electrode side insulating portion 62 are integrated, thereby eliminating the clearance between the parts. Can be done.

(Connection configuration example)
Next, with reference to FIG. 9, a configuration example of the connection points of the battery cell 2, the circuit board 4, and the positive electrode side external terminal 6 will be described. In the following, a configuration example of the connection portion on the positive electrode side external terminal 6 side will be described, but the configuration of the connection portion on the negative electrode side external terminal 7 side is the same as the configuration of the connection portion on the positive electrode side external terminal 6 side. It is said that.

FIG. 9A is a perspective view of the entire battery pack 1, and FIG. 9B is an enlarged view of a cross section on the positive electrode side when the battery pack 1 is cut along the cutting line BB in FIG. 9A. In FIG. 9B, the insulating tape 5 and the connecting circuit board 41 are not shown as appropriate.

As shown in FIG. 9B, the innermost surface of the plurality of surfaces (the surface substantially orthogonal to the longitudinal direction of the battery tube 3) of the positive electrode side circuit board 42 and the positive electrode terminal 21 are designated by reference numeral AX. It is welded at the place where it was made. Further, a predetermined surface of the positive electrode side circuit board 42 (for example, the third surface when viewed from the outside of the battery tube 3) and the vicinity of the tip of the positive electrode tab 620 bent in a U shape when viewed in cross section are reference numerals. It is welded at the place where BX is attached. As a result, the battery cell 2, the circuit board 4, and the positive electrode side external terminal 6 are electrically connected.

In the present embodiment, the positive electrode side circuit board 42 has a reinforcing plate 42B, and the positive electrode side external terminal 6 has a reinforcing portion 630. By forming the circuit board 4 with a flexible printed circuit board, the thickness of the substrate can be reduced, but since the flexible printed circuit board has a lower strength than the PCB (Printed Circuit Board), when an impact is applied to the positive electrode side conductive portion 61. The positive electrode side conductive portion 61 may be pushed into the outer tube 3, or the welded portion between the positive electrode tab 620 and the positive electrode side circuit board 42 may be disconnected. However, in the present embodiment, since the reinforcing portion 630 receives the positive electrode side conductive portion 61, the positive electrode side conductive portion 61 is pushed into the outer tube 3 even when an impact is applied due to a drop of the battery pack 1 or the like. Can be prevented. Further, by providing the reinforcing plate 42B, the deformation of the positive electrode side circuit board 42 can be suppressed, so that it is possible to prevent the positive electrode side circuit board 42 and the positive electrode tab 620 from being disconnected.

(Circuit configuration example)
Subsequently, a circuit configuration example of the battery pack 1 will be described with reference to FIG. 10. As shown in FIG. 10, the positive electrode terminal 21 is led out from the positive electrode side of the battery cell 2 via the power line PL1. Further, the negative electrode terminal 22 is led out from the negative electrode side of the battery cell 2 via the power line PL2.

The protection circuit 43C described above is, for example, a one-chip IC (Integrated Circuit) having a discharge control FET (Field Effect Transistor) 431, a charge control FET 432, and a control unit 440. Although the discharge control FET (Field Effect Transistor) 431 and the charge control FET 432 are connected to the power line PL2, they may be connected to the power line PL1. The control unit 440 is connected between the power lines PL1 and PL2.

The operation of the discharge control FET 431 and the charge control FET 432 is controlled by the control unit 440. For example, the discharge control FET 431 is turned off when the battery voltage reaches the over-discharge detection voltage or when an over-current is detected, and is controlled so as to block the discharge current flowing in the current path of the battery cell 2. Further, the charge control FET 432 is turned off when the voltage of the battery cell 2 becomes the overcharge detection voltage, and is controlled so as to block the charge current flowing in the current path of the battery cell 2.

(Example of battery pack manufacturing method)
Subsequently, an example of a method for manufacturing the battery pack 1 will be described. First, the positive electrode terminal 21 and the positive electrode side circuit board 42 are welded. Further, the negative electrode terminal 22 and the negative electrode side circuit board 43 are welded. Then, the assy 8 is formed by winding the insulating tape 5. Then, after the positive electrode side circuit board 42 and the positive electrode tab 620 are welded, the negative electrode side of the assembly 8 is inserted into the outer tube 3 from the positive electrode side of the outer tube 3, and the positive electrode side external terminal 6 is the positive electrode of the outer tube 3. It is press-fitted to the side. As the positive electrode side external terminal 6 is press-fitted, the positive electrode side circuit board 42 is bent so as to be folded. The positive electrode side circuit board 42 may be bent in advance. Then, after the negative electrode side circuit board 43 and the negative electrode tab of the negative electrode side external terminal 7 are welded, the negative electrode side external terminal 7 is press-fitted into the negative electrode side of the exterior tube 3 to form the battery pack 1. .. Of course, the battery pack 1 may be manufactured by another manufacturing method.

[Characteristics of battery pack]
(First feature)
Subsequently, with reference to FIGS. 11 and 12, the first feature of the battery pack 1 according to the present embodiment will be described. FIG. 11A shows the assembly 8 of the battery pack 1, and FIG. 11B shows a cross section of the assembly 8 when the assembly 8 is cut along the cutting line CC in FIG. 11A. In FIG. 11B, the illustration of the insulating tape 5 is omitted as appropriate.

As described above, the battery cell 2 has a heat-sealing portion 240 on the side peripheral surface. The connecting circuit board 41 is arranged in a range of the side peripheral surface that does not overlap with the heat fusion portion 240. For example, if the connecting circuit board 41 is arranged on the side opposite to the heat fusion portion 240, the thickness of the connecting circuit board 41 will be included in the diameter of the assembly 8, and the volumetric energy density will decrease. .. However, as shown in FIG. 11B, by arranging the connecting circuit board 41 along the heat fusion portion 240, the thickness of the connecting circuit board 41 can be prevented from being included in the diameter of the assembly 8. .. Therefore, the battery pack 1 can be miniaturized, and it is possible to suppress a decrease in the volumetric energy density.

FIG. 12 is a diagram specifically showing a certain range in which the connecting circuit board 41 is arranged. The range in which the connection circuit board 41 is arranged is set as follows, for example. In addition, it should be noted.
・ The thickness (maximum value) of the heat-sealed portion 240 is s.
-F the thickness of the connecting circuit board 41
-The radius of the battery cell 2 excluding the heat-sealed portion 240 is c.
-The radius of the battery cell 2 including the heat-sealing portion 240 is (2c + s) / 2.
And. These values are known by specifications and measurements.

_{From the formula described below, an angle θ 2} that does not affect the outer diameter dimension of the battery cell 2 including the heat-sealing portion 240 (the outer diameter does not increase) is obtained even if the connecting circuit board 41 having a thickness f is arranged. The connecting circuit board 41 is arranged in a range based on an _{angle θ 1} (absolute value) smaller than the angle.

The angle θ ₂ is set as follows.
(Procedure P1)
The center point of the outer diameter of the battery cell 2 (excluding the heat-sealed portion 240) is PA, the center point of the outer diameter of the battery cell 2 including the heat-sealed portion 240 is PB, and the one away from the heat-sealed portion 240. The location of the connecting circuit board 41 that is arranged on the end surface of the connecting circuit board 41 and is not in contact with the peripheral surface of the battery cell 2 is set with the PC (see FIG. 12).

(Procedure P2)
Assuming that the side between PA and PC is side LA, the side between PB and PA is side LB, and the side between PB and PC is side LC, the length of each side is defined as follows.
LA = f + c
LB = (2c + s) / 2-c = s / 2
LC = (2c + s) / 2

When the angle between the sides LA and the side LB an angle theta _2, the angle theta ₂ may be expressed from the equation 1 below.
(Equation 1) cos θ ₂ = (cs-2cf-f ² ) / s (c + f)

(Procedure P3)
_{The angle θ 2} can be obtained by substituting the known values of c, f, and s into Equation 1. Then, when the connection circuit board path 41 is actually arranged, the end portion of the connection circuit board 41 in the direction opposite to the heat fusion portion 240 side, the center of the outer diameter of the battery cell 2, and the heat fusion portion 240 the center and the angle formed in the outer diameter of the battery cell 2 in the case of the theta ₁ comprising, by placing the connection circuit board 41 so as to satisfy the theta ₂ ≧ theta _1, increasing the diameter of the battery cell 2 However, the connection circuit board 41 can be arranged. That is, the increased diameter space created by the heat-sealing portion 240 can be appropriately and effectively utilized.

(Second feature)
Subsequently, with reference to FIG. 13, the second feature of the battery pack 1 according to the present embodiment will be described. FIG. 13 shows the internal structure of the battery pack 1 near the end (near the positive electrode). The positive electrode side external terminal 6 has an insertion portion 651 that is inserted into the outer tube 3 in a state of being press-fitted into the outer tube 3, and a non-insertion portion 652 that is not inserted into the outer tube 3. The insertion portion 651 includes, for example, a positive electrode side flange portion 63 and a part of the positive electrode side insulating portion 62 (near the inner surface 601B). Further, the non-insertion portion 652 includes, for example, a positive electrode side conductive portion 61 and a part of the positive electrode side insulating portion 62 (near the outer surface 601A).

In the present embodiment, the elastic resin 81 is provided near the end inside the outer tube 3. Specifically, the elastic resin 81 is provided so as to come into contact with the battery cell 2, the positive electrode side external terminal 6, and the circuit board 4. More specifically, the elastic resin 81 is provided so as to come into contact with the positive electrode terminal 21 of the battery cell 2, the insertion portion 651 of the positive electrode side external terminal 6, and the positive electrode side circuit board 42 of the circuit board 4. For example, the elastic resin 81 before curing is filled, and the positive electrode side external terminal 6 is press-fitted, and then the elastic resin 81 is cured.

As the elastic resin 81, for example, a bond containing a silyl group-terminated polymer having a hardness of Shore A30 to 70 after curing as a main component can be used. More preferably, a bond having a hardness of Shore A50 is used as the elastic resin 81. Shore A50 has a hardness similar to that of a plastic eraser. By using such an elastic resin 81, the impact at the time of dropping can be absorbed by the elastic resin 81. Further, a bond having a viscosity of 5 to 200 Pa · s can be applied. As a result, it is possible to prevent the filled bond from unnecessarily invading the inside of the outer pipe 3. Further, it is possible to prevent the positive electrode side external terminal 6 from coming off (disengaging) from the outer tube 3 by curing the filled elastic resin 81. Further, since the notch portions 63A and 63B are formed in the positive electrode side external terminal 6, the elastic resin 81 is provided on the inner surface of the outer tube 3 via the notch portions 63A and 63B, so that the positive electrode side external terminal 6 is provided. Can be firmly fixed to the outer tube 3.

As shown in FIG. 14, the elastic resin 81 may be provided in the same manner at the place where the negative electrode side external terminal 7 is inserted into the outer tube 3. Preferably, the elastic resin 81 is provided on both the positive electrode side and the negative electrode side.

<Modification example>
Although the embodiments of the present invention have been specifically described above, the contents of the present invention are not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible. Hereinafter, a modified example will be described.

As shown in FIG. 15A, a recessed portion 85 (also referred to as a punch or the like) recessed toward the inside of the exterior pipe 3 may be formed near the end of the exterior pipe 3. The recessed portion 85 is formed, for example, at a portion corresponding to the cutout portion 63A of the positive electrode side external terminal 6. As a result, as shown in FIG. 15B, the convex portion of the recessed portion 85 into the outer tube 3 reaches the elastic resin 81 via the notched portion 63A. By forming the recessed portion 85 before the elastic resin 81 is cured, the elastic resin 81 can be joined to the recessed portion 85 after being cured. Therefore, it is possible to reliably prevent the positive electrode side external terminal 6 from coming off the outer tube 3. Of course, a recess may be formed near the end on the negative electrode side.

As shown in FIGS. 16A to 16F, the shapes of the cutout portions 63A and 63B can be changed as appropriate. For example, as shown in FIG. 16A, the shape of the notch may be U-shaped. As shown in FIG. 16B, it may be a relatively deep notch. Further, as shown in FIGS. 16C and 16D, the notch portion may have a tapered shape in which the width becomes narrower toward the tip end (inner surface 601B side). Further, as shown in FIG. 16E, the corner near the open end of the cutout portion may be cut. Further, as shown in FIG. 16F, the shape of the notch portion may be a shape in which the width on the tip side is larger than the width on the open end side. By forming the shape as shown in FIG. 16F, the recessed portion 85 described above can be in strong contact with the notched portion, so that the positive electrode side external terminal 6 and the outer tube 3 can be more firmly fixed. Further, the number of notched portions is not limited to two, and may be an appropriate number.

In the above-described embodiment, the heat-sealing portion 240 may be simply bent without being heat-sealed to the peripheral surface of the outer tube 3, or the heat-sealing portion 240 is made of resin. It may have been done. Further, the shape of the outer tube 3 is not a cylindrical shape, and may be a substantially cylindrical shape or a columnar shape as long as the gist of the present invention is not deviated. The present invention can also be applied to batteries other than lithium ion secondary batteries. Further, depending on the shape of the circuit board 4, the entire circuit board may have the same arrangement position and shape as a part of the circuit board in the above-described embodiment.

The battery pack 1 may have both the first and second features described above. Further, the features of the battery pack 1 are not limited to the first and second features described above, and may be characterized by any configuration and function of the matters disclosed in the present specification.

<Application example>
[Wristband type electronic device as an application example]
Hereinafter, an application example in which the present invention is applied to a wristband type electronic device will be described. Wristband-type electronic devices, also called smart bands, are simply wrapped around the arm to provide data on human activities such as steps, distance traveled, calories burned, sleep volume, and heart rate, and the external environment such as temperature and humidity. It is possible to acquire data related to. Furthermore, the acquired data can be managed by a smartphone or the like. Further, it may have a function of sending and receiving e-mails, and for example, an incoming e-mail can be notified to the user by an LED (Light Emitting Diode) lamp and / or vibration.

FIG. 17 shows an external example of the wristband type electronic device 1601. The electronic device 1601 is a watch-type wearable device that can be attached to and detached from the human body. The electronic device 1601 includes a band portion 1611 worn on the arm, a display device 1612 for displaying numbers, characters, symbols, and the like, and an operation button 1613.

In the electronic device 1601, the band portion 1611 is curved so as to be substantially circular as shown in FIG. 17, and the protrusion 1611b is inserted into the hole portion 1611a and attached to the arm. A sensor (not shown) is partially or wholly provided inside the band portion 1611, and various data described above can be acquired. The sensor may be provided so as to be mounted on the circuit board on the display device 1612 side.

FIG. 18 shows an example of a circuit configuration of the electronic device 1601. In addition to the display device 1612 described above, the electronic device 1601 includes a controller IC 1615 as a drive control unit, a sensor 1620, a host device 1616, and a battery pack 1617 as a power source. The sensor 1620 may include a controller IC 1615.

The sensor 1620 can detect both pressing and bending. The sensor 1620 detects a change in capacitance in response to pressing, and outputs an output signal corresponding to the change to the controller IC 1615. Further, the sensor 1620 detects a change in resistance value (resistance change) according to bending, and outputs an output signal corresponding to the change (resistance change) to the controller IC 1615. The controller IC 1615 detects the pressing and bending of the sensor 1620 based on the output signal from the sensor 1620, and outputs information according to the detection result to the host device 1616.

The host device 1616 executes various processes based on the information supplied from the controller IC 1615. For example, processing such as displaying character information, image information, and the like on the display device 1612, moving the cursor displayed on the display device 1612, scrolling the screen, and the like is executed.

The display device 1612 is, for example, a flexible display device that displays a screen based on a video signal, a control signal, or the like supplied from the host device 1616. Examples of the display device 1612 include, but are not limited to, a liquid crystal display, an electroluminescence (EL) display, and electronic paper.

The battery pack 1 according to the above-described embodiment or a modification thereof can be applied to the battery pack 1617.

The present invention can be applied to various electronic devices having a battery, and is not limited to the wristband type electronic device 1601 described in the above application example. Examples of electronic devices other than the above-mentioned application examples include combustion-type smoking devices (electronic cigarettes), portable devices such as smartphones, eyeglass-type terminals (head-mounted displays, etc.), toys, and the like.

1 ... Battery pack 2 ... Battery cell 3 ... Exterior tube 4 ... Circuit board 5 ... Insulation tape 6 ... Positive electrode side external terminal 7 ... Negative electrode side external terminal 21 ... Positive electrode terminal 22 ... Negative electrode terminal 41 ... Connecting circuit board 42 ... Positive electrode side circuit board 43 ... Negative electrode side circuit board 43A ... Protection circuit 61 ... Positive electrode side conductive part 62 ... Positive electrode Side insulating parts 63A, 63B ... Notch 71 ... Negative electrode side conductive part 72 ... Negative electrode side insulating part 240 ... Heat fusion part 630 ... Reinforcing part

Claims (9)

1. It has a cylindrical exterior tube, a wiring portion, and a cylindrical battery cell provided with a film-shaped exterior material.
   External terminals are provided at both ends of the outer tube.
   The battery cell has a heat-sealed portion on the side peripheral surface, and has a heat-sealed portion.
   A battery pack in which the wiring portion is arranged in a range of the side peripheral surface that does not overlap with the heat fusion portion.
2. The battery pack according to claim 1, wherein the wiring portion is composed of a first circuit board.
3. The battery pack according to claim 2, wherein the thickness of the first circuit board is equal to or less than the thickness of the heat-sealed portion.
4. The range in which the first circuit board is arranged on the side peripheral surface includes the thickness of the end portion of the first circuit board in the direction opposite to the heat fusion portion side and the outer diameter of the battery cell. and the center of an angle and forms the center of the outer diameter of the battery cell containing the heat-fusible portion when the θ _1, θ ₂ ≧ θ ₁ to claim 2 or 3 is set to satisfy the Described battery pack.
   However, the θ ₂ is a _{value satisfying cos θ 2} = (cs-2cf−f ² ) / s (c + f), c is the radius of the battery cell not including the heat-sealed portion, and f is the said. It is the thickness of the first circuit board, and s indicates the thickness of the heat-sealed portion.
5. The battery pack according to any one of claims 2 to 4, wherein the battery cell and the first circuit board are held by an insulating tape.
6. Has a second circuit board
   The second circuit board is provided between the end of the battery cell and the external terminal.
   The battery pack according to any one of claims 2 to 5, which is a flexible printed circuit board in which the first circuit board and the second circuit board are integrally formed.
7. The battery pack according to claim 6, wherein a control unit for controlling charging / discharging of the battery cell and a charging / discharging switch are provided on the second circuit board.
8. A claim that the external terminal has a conductive portion made of metal, an insulating portion provided so as to surround the conductive portion, and a reinforcing portion made of resin on a part of the inner side of the conductive portion. The battery pack according to any one of 1 to 7.
9. An electronic device having the battery pack according to any one of claims 1 to 8.

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