Battery pack and electronic device

Abstract

A battery pack, comprising: a secondary battery; and a circuit board, the secondary battery having: a metal exterior; a first external terminal disposed at the center of an end face of the metal exterior; and a second external terminal disposed so as to surround the periphery of the first external terminal, the circuit board having: a first connection portion connected to the first external terminal; and a second connection portion connected to the second external terminal, an insulating portion for insulating the first connection portion and the second connection portion being provided in the battery pack, the first connection portion and the second connection portion being disposed in the same plane.

Description

Technical Field

[0001] The present invention relates to a battery pack and an electronic device. Background Art

[0002] There is known a coin-shaped secondary battery, i.e., a coin-type secondary battery. For example, in Patent Document 1 described below, there is described a coin-type secondary battery in which a positive electrode terminal and a negative electrode terminal are provided on two end faces, respectively, and a potential of one polarity is led out through an FPC (Flexible Printed Circuits).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-142170 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] In the technology described in Patent Document 1, since a potential of one polarity is led out from the side surface of the coin-type secondary battery through an FPC, the size of the coin-type secondary battery increases. In addition, depending on the connection method, it is necessary to turn over the coin-type secondary battery, which may deteriorate the assembly workability. In view of this point, a structure in which a positive electrode terminal and a negative electrode terminal are provided on one end face of the coin-type secondary battery can be considered. However, since both the positive electrode terminal and the negative electrode terminal are arranged on one end face, it is necessary to appropriately ensure insulation.

[0008] Therefore, one object of the present invention is to provide a battery pack and an electronic device that can appropriately ensure insulation even in a structure in which both a positive electrode terminal and a negative electrode terminal are arranged on one end face.

[0009] Technical Solution for Solving the Technical Problem

[0010] The present invention is a battery pack having:

[0011] a secondary battery; and

[0012] a circuit board,

[0013] The secondary battery has:

[0014] a metal exterior portion;

[0015] a first external terminal disposed at the center of the end face of the metal exterior portion; and

[0016] a second external terminal disposed so as to surround the periphery of the first external terminal,

[0017] The circuit board has:

[0018] A first connection part, which is connected to a first external terminal; and

[0019] A second connection part, which is connected to a second external terminal,

[0020] The battery pack is provided with an insulating part that insulates the first connection part and the second connection part,

[0021] The first connection part and the second connection part are arranged in the same plane.

[0022] The present invention may also be an electronic device having the above-described battery pack.

[0023] Advantages of the Invention

[0024] According to at least one embodiment of the present invention, appropriate insulation can be ensured even in a structure in which both the positive terminal and the negative terminal are arranged on one end face. It should be noted that the content of the present invention should not be construed as being limited to the effects exemplified in this specification. Description of the Drawings

[0025] Figure 1 is an exploded perspective view of a battery pack according to one embodiment.

[0026] Figure 2 is a diagram showing an external appearance example of a secondary battery according to one embodiment.

[0027] Figure 3 is a diagram referred to when explaining an internal structure example of a secondary battery according to one embodiment.

[0028] Figure 4 is a diagram referred to when explaining a structure example of an FPC according to one embodiment.

[0029] Figure 5 is a half-sectional view of a battery pack according to one embodiment.

[0030] Figure 6 is a diagram showing an enlarged partial cross-section of a battery pack according to one embodiment.

[0031] Figure 7 is a diagram for explaining a modification example.

[0032] Figure 8 is a diagram for explaining an application example.

[0033] Figure 9 is a diagram for explaining an application example. Detailed Description of the Embodiments

[0034] Hereinafter, with reference to the accompanying drawings, embodiments of the present invention and the like will be described. It should be noted that the description will be carried out in the following order.

[0035] <One Embodiment>

[0036] <Modification Example>

[0037] <Application Example>

[0038] The embodiments and the like described below are preferred specific examples of the present invention, and the content of the present invention is not limited to these embodiments and the like.

[0039] It should be noted that the components shown in the claims are not limited to the components of the embodiments. In particular, as long as there is no record with a special limiting meaning in the records of the size, material, shape, relative configuration, and directions such as up, down, left, and right of the constituent components in the embodiments, it is not the idea of limiting the scope of the present invention only to this, but only a simple explanatory example. It should be noted that the size, positional relationship, etc. of the components shown in each drawing may be exaggerated for clarity of explanation. In addition, in order to prevent the drawing from being too complicated, sometimes only a part of the reference numerals is shown, and sometimes a part of the drawing is simplified. In addition, in the following description, components with the same name and reference numerals represent the same or homogeneous components, and repeated descriptions are appropriately omitted. In addition, each element constituting the present invention may also be in a manner where a single component constitutes multiple elements, or a single component combines multiple elements, and conversely, the functions of a single component may be shared by multiple components.

[0040] <One Embodiment>

[0041] [Structural Example of Battery Pack]

[0042] Refer to Figures 1 to 6 , and a structural example of a battery pack according to one embodiment will be described. Figure 1 is an exploded perspective view of a battery pack according to one embodiment. Figure 2 is a diagram showing an external appearance example of a secondary battery according to one embodiment. Figure 3 is a diagram referred to when explaining an internal structural example of a secondary battery according to one embodiment. Figure 4 is a diagram referred to when explaining a structural example of an FPC according to one embodiment. Figure 5 is a half-sectional view of a battery pack according to one embodiment. Figure 6 is a diagram enlarging a partial cross-section of a battery pack according to one embodiment. It should be noted that in this specification, a battery pack refers to a battery pack having a structure in which a circuit board is connected to a secondary battery.

[0043] As Figure 1As shown, a battery pack (battery pack 10) according to an embodiment includes a secondary battery 1, a first insulating plate 2 as an example of an insulating portion, an FPC 3 as an example of a circuit board, and a second insulating plate 4 as an example of another insulating portion. The secondary battery 1 has a metal exterior portion 101 formed in a cylindrical shape. On an end face 101A (the upper surface in Figure 1 ) of one end face of the metal exterior portion 101, the first insulating plate 2, the FPC 3, and the second insulating plate 4 are sequentially stacked and connected by an appropriate method to complete the battery pack 10 according to an embodiment (refer to Figure 5 ).

[0044] A positive terminal 110 as an example of a first external terminal is disposed at the center portion (a portion near the center) of the end face 101A of the metal exterior portion 101. A negative terminal 120 as an example of a second external terminal is disposed so as to surround the positive terminal 110.

[0045] The size of the first insulating plate 2 is slightly smaller than the end face 101A of the metal exterior portion 101 and has a generally circular shape as a whole. As the first insulating plate 2, a polyimide (PI) film or non-woven fabric can be used. In the case of using non-woven fabric, from the viewpoints of insulation and flame retardancy, non-woven fabric containing aromatic polyamide fibers is more preferable. The first insulating plate 2 has a circular opening 201 at the central portion, and rectangular openings 202 and 203 are provided around the opening 201. The first insulating plate 2 is mounted on the end face 101A of the metal exterior portion 101 by bonding or the like. In the present embodiment, the opening 201 corresponds to a third opening provided at a portion corresponding to a later-described opening 352. In addition, the openings 202 and 203 correspond to fourth openings. The opening 202 is provided at a portion corresponding to a later-described opening 362, and the opening 203 is provided at a portion corresponding to a later-described opening 372.

[0046] The FPC 3 has a connection portion 301 provided at the central portion and connection portions 302 and 303 provided around the connection portion 301. The connection portion 301 is connected to the positive terminal 110 via the opening 201. The connection portion 302 is connected to the negative terminal 120 via the opening 202. The connection portion 303 is connected to the negative terminal 120 via the opening 203. In the present embodiment, the connection portion 301 corresponds to a first connection portion, and the connection portions 302 and 303 correspond to second connection portions.

[0047] The second insulating plate 4 covers at least a part of the opposite surface of the FPC 3 that contacts the first insulating plate 2. Specifically, the second insulating plate 4 has a size capable of covering the connection portions 301, 302, and 303 and has a circular shape. By the second insulating plate 4, the connection portions 301 connected to the positive terminal 110, and the connection portions 302 and 303 connected to the negative terminal 120 are blocked, so the safety of the battery pack 10 can be ensured. As the second insulating plate 4, a polyimide film or a non-woven fabric can be used. In the case of using a non-woven fabric, from the viewpoints of insulation and flame retardancy, a non-woven fabric containing aromatic polyamide fibers is more preferable.

[0048] (Regarding a secondary battery)

[0049] Next, details of the secondary battery 1 according to an embodiment will be described. As described above, the secondary battery 1 has a metal exterior portion 101. As Figure 2 shown, the metal exterior portion 101 has, for example, a hollow cylindrical metal exterior portion 101B that is open at the top and a lid-shaped metal exterior portion 101C disposed at the open end of the metal exterior portion 101B. The metal exterior portion 101C forms the above-described end face 101A. For example, the peripheries of the metal exterior portion 101B and the metal exterior portion 101C are fusion-welded.

[0050] As Figure 3 shown, on the metal exterior portion 101C, a step 130 is formed at a predetermined position in the direction from the periphery toward the center portion, and a circular concave portion 131 is formed on the center portion side. A circular opening is formed at the center of the concave portion 131. In the concave portion 131, the above-described positive terminal 110 is disposed with an insulating member 132 interposed therebetween. The positive terminal 110 and the insulating member 132 also have a circular shape and have a circular opening at the center portion. The openings of the positive terminal 110, the insulating member 132, and the concave portion 131 are arranged to communicate with each other in the vertical direction, and a rivet 140 is driven and riveted at the portion of the opening. The rivet 140 has, for example, a shape with an H-shaped cross section. It should be noted that insulating members 135 are respectively disposed between the rivet 140 and the negative terminal 120 and the insulating member 132.

[0051] The battery element 150 is housed inside the metal exterior portion 101. The top insulator 151 is disposed on the upper side of the battery element 150, and the bottom insulator 152 is disposed on the lower side of the battery element 150. The negative electrode side of the battery element 150 is connected to the bottom surface of the metal exterior portion 101B via the negative electrode lead 160 by means of soldering or the like. Through this connection, the entire metal exterior portion 101 has a negative polarity and functions as the negative terminal 120. In addition, the positive electrode side of the battery element 150 is connected to the lower side of the rivet 140 via the positive electrode lead 161 by soldering. Through this connection, the positive terminal 110 in contact with the rivet 140 has a positive polarity.

[0052] As the positive terminal 110, for example, a nickel plate can be used. As the metal exterior portion 101 that functions as the negative terminal 120, a component obtained by nickel plating the portion of the end face 101A on a component made of stainless steel can be used. As the material of the rivet 140, for example, aluminum can be used. It should be noted that these materials are just examples and are not limited to the exemplified materials.

[0053] It should be noted that the terminals in the positive terminal or negative terminal in this specification are not limited to physical contacts, as long as they have a positive or negative polarity structure. For example, like the metal exterior portion 101 in this embodiment, the shape can be a housing shape.

[0054] (Regarding the FPC)

[0055] Next, the details of the FPC 3 according to one embodiment will be described. As Figure 4 and Figure 5 shown, the FPC 3 has a circular base portion 310, a rectangular intermediate portion 311 extending from a specified peripheral edge of the base portion 310, and an oval front end portion 312 located at the front end of the intermediate portion 311, and they have a structure formed integrally.

[0056] The above-mentioned connection portion 301 is formed at the center portion of the base portion 310. In addition, the above-mentioned connection portions 302 and 303 are formed around the connection portion 301 provided on the base portion 310. In this way, the connection portions 301, 302, and 303 are arranged in the same plane.

[0057] In addition, connection terminals such as copper plates for connecting to external devices are formed on the front end portion 312. For example, the connection terminal 321 and the connection terminal 322 are formed on the front end portion 312. In this way, the connection terminal 321 and the connection terminal 322 are provided on the same substrate as the FPC 3.

[0058] The connection terminal 321 is connected to the connection portion 301 through a prescribed pattern. The connection terminal 321 functions as an output terminal on the positive electrode side. The connection terminal 322 is connected to at least one of the connection portion 302 and the connection portion 303 through a prescribed pattern. The connection terminal 322 functions as an output terminal on the negative electrode side. It should be noted that a connector may also be provided at the front end portion 312. Circular hole portions 325 and 326 are formed near both ends of the front end portion 312. The hole portions 325 and 326 are hole portions for positioning the secondary battery 1 and the FPC 3. For example, the secondary battery 1 and the FPC 3 are positioned by inserting a pin-shaped jig into the hole portions 325 and 326.

[0059] As Figure 6 shown, the FPC 3 has, for example, polyimide sheets 341 and 342 laminated in two layers. In addition, the connection portion 301 has a tab 351. As the tab 351, a copper foil or a nickel tab or the like can be used. The tab 351 has a circular opening 352 at the central portion (refer to Figure 4 ). The periphery of the tab 351 is sandwiched and supported by the polyimide sheets 341 and 342. As Figure 4 and Figure 6 shown, a preliminary solder 353 is provided on the upper side of the exposed portion (the portion not sandwiched by the polyimide sheets 341 and 342) of the tab 351, and a preliminary solder 354 is provided on the lower side. The preliminary solder refers to a small amount of solder provided in advance on the portion to be welded in order to improve the weldability. For example, a low melting point solder paste can be used.

[0060] The connection portion 302 has a tab 361. As the tab 361, a copper foil or a nickel tab or the like can be used. The tab 361 has an oblong opening 362 at the central portion (refer to Figure 4 ). The periphery of the tab 361 is sandwiched and supported by the polyimide sheets 341 and 342. As Figure 5 shown, a preliminary solder 363 is provided on the upper side of the exposed portion of the tab 361, and a preliminary solder 364 is provided on the lower side.

[0061] The connection portion 303 has a tab 371. As the tab 371, a copper foil or a nickel tab or the like can be used. The tab 371 has an oblong opening 372 at the central portion (refer to Figure 4 ). The periphery of the tab 371 is sandwiched and supported by the polyimide sheets 341 and 342. As Figure 4 and Figure 6 shown, a preliminary solder 373 is provided on the upper side of the exposed portion of the tab 371, and a preliminary solder 374 is provided on the lower side.

[0062] In this embodiment, the opening 352 corresponds to the first opening. Additionally, the openings 362 and 372 correspond to the second opening.

[0063] [Method for manufacturing a battery pack]

[0064] Next, an example of the method for manufacturing the battery pack 10 will be described. First, the first insulating plate 2 is mounted on the end face 101A of the secondary battery 1 by bonding or the like. Then, for example, the FPC 3 is positioned by inserting pin-shaped jigs into the hole portions 325 and 326. As Figure 6 shown, in the state where the FPC 3 is positioned, the opening 352 communicates with the opening 201 of the first insulating plate 2, and a state is formed in which the front end of the rivet 140 can be seen through the communicating portion. Additionally, the bottom surface of the preliminary solder 354 faces the positive terminal 110 with a facing gap of the amount of the thickness of the first insulating plate 2. Further, in the state where the FPC 3 is positioned, the opening 362 communicates with the opening 202 of the first insulating plate 2, and a state is formed in which a part of the metal exterior portion 101C can be seen through the communicating portion. Additionally, the bottom surface of the preliminary solder 364 faces a part of the metal exterior portion 101C with a facing gap of the amount of the thickness of the first insulating plate 2. Further, as Figure 6 shown, in the state where the FPC 3 is positioned, the opening 372 communicates with the opening 203 of the first insulating plate 2, and a state is formed in which a part of the metal exterior portion 101C can be seen through the communicating portion. Additionally, the bottom surface of the preliminary solder 374 faces a part of the metal exterior portion 101C with a facing gap of the amount of the thickness of the first insulating plate 2.

[0065] In the state where the FPC 3 is positioned, for example, a heat chip is pressed against the portion of the preliminary solder 353. As a result, the preliminary solder 353 melts, and in addition, the heat of the heat chip is transferred to the lower preliminary solder 354, and the preliminary solder 354 melts. The molten solder flows downward. After a certain time, the heat chip is separated, and the molten solder solidifies. Thus, the tab 351 and the positive terminal 110 are connected by solder.

[0066] Similarly, in the state where the FPC 3 is positioned, for example, a heat chip is pressed against the portion of the preliminary solder 363. Similar to the solder connection in the connection portion 301 described above, the tab 361 and the metal exterior portion 101C, that is, the negative terminal 120, are connected by solder. Similarly, in the state where the FPC 3 is positioned, for example, a heat chip is pressed against the portion of the preliminary solder 373. Similar to the solder connection in the connection portion 301 described above, the tab 371 and the metal exterior portion 101C, that is, the negative terminal 120, are connected by solder.

[0067] In Figure 5The state shown, that is, after the solder connection is completed, the second insulating plate 4 is mounted on the upper surface of the FPC 3 by adhesion or the like. As described above, the battery pack 10 is completed.

[0068] As described above, the connection portion 301 is connected to the connection terminal 321 by a predetermined pattern. Thus, the output on the positive electrode side can be output to the outside via the connection portion 301 and the connection terminal 321 solder-connected to the positive electrode terminal 110. In addition, at least one of the connection portion 302 and the connection portion 303 is connected to the connection terminal 322 by a predetermined pattern. Thus, the output on the negative electrode side can be output to the outside via at least one of the connection portions 302 and 303 solder-connected to the negative electrode terminal 120 and the connection terminal 322. It should be noted that when the connection terminals 321 and 322 are connected to an external device, the middle portion 311 of the FPC 3 can be bent.

[0069] It should be noted that when connecting the connection portion 301 to the positive electrode terminal 110, there is a possibility that due to the flow of molten solder, the connection portion 301 is also solder-connected to the negative electrode terminal 120, resulting in a short circuit. Conversely, when connecting the connection portions 302 and 303 to the negative electrode terminal 120, there is a possibility that due to the flow of molten solder, the connection portions 302 and 303 are also solder-connected to the positive electrode terminal 110, resulting in a short circuit. However, in the present embodiment, the first insulating plates 2 are respectively disposed between the connection portion 301 and the connection portion 302, and between the connection portion 301 and the connection portion 303. Therefore, it is possible to prevent a short circuit caused by the molten solder flowing to the other electrode side.

[0070] [Effects that can be obtained by this embodiment]

[0071] By this embodiment, the following effects can be obtained.

[0072] It is possible to draw out the potentials of the positive electrode and the negative electrode from the same surface. It is possible to reduce the size of the FPC 3 and miniaturize the battery pack 10.

[0073] When connecting the FPC 3, it is not necessary to turn over the secondary battery 1, and the process can be simplified.

[0074] By the first insulating plate 2, the positive electrode terminal 110 and the negative electrode terminal 120 can be appropriately insulated. In addition, it is not necessary to wind an insulating tape around the secondary battery 1.

[0075] If the FPC 3 is held by a tube, the holding force of the FPC 3 is reduced when mounting components on the surface held by the tube, but such a problem does not occur in the present embodiment, so the impact resistance is improved.

[0076] <Variation>

[0077] As described above, a specific embodiment of the present invention has been described in detail. However, the content of the present invention is not limited to the above-described embodiment, and various modifications can be made based on the technical idea of the present invention.

[0078] The FPC3 in the above-described embodiment may also be Figure 7 the FPC3A shown in the figure. The FPC3A has a copper foil 381 formed at the center portion and copper foils 382 and 383 formed outside the copper foil 381 at the base portion 310. The copper foil 381 corresponds to the first connection portion, and the copper foils 382 and 383 correspond to the second connection portion. Different from the embodiment, no opening is formed at the portion where each copper foil is formed.

[0079] The copper foil 381 is connected to the positive terminal 110, and the copper foils 382 and 383 are connected to the negative terminal 120. In this way, the first connection portion and the second connection portion may not necessarily have openings. It should be noted that each copper foil is connected by laser welding, ultrasonic welding, resistance welding, etc.

[0080] In the above-described embodiment, instead of using solder connection, laser solder welding, laser welding, ultrasonic welding, resistance welding, etc. may be used.

[0081] In the above-described embodiment, the first external terminal may be the negative electrode, and the second external terminal may be the positive electrode. In addition, in the above-described embodiment, the structure corresponding to the insulating portion may not be the first insulating plate 2, but the insulating member of the FPC3, that is, the PI film. In addition, in the above-described embodiment, the circuit board may not be the FPC3, but a metal plate covered with insulation. In addition, in the above-described embodiment, the rivet 140 may not be provided. In addition, the shape of the metal exterior portion 101 is not limited to a cylindrical shape, and may be other shapes such as a prismatic shape. In addition, an IC (Integrated Circuit) that performs a known protection operation on the battery pack 10 may be mounted on the FPC3.

[0082] The matters described in the above-described embodiments and modification examples can be appropriately combined. In addition, the materials, processes, etc. described in the embodiments are merely examples, and the content of the present invention is not limited to the exemplified materials, etc.

[0083] [Application Example]

[0084] The battery pack according to the present invention can be mounted on various electronic devices such as wireless earphones, power tools, electric vehicles, etc. or used for supplying power.

[0085] A specific application example will be described. For example, the above-described battery pack can be used as a power source for a wearable device having the function of a portable information terminal, that is, a so-called wearable terminal. As the wearable terminal, for example, a watch-type terminal, a glasses-type terminal, etc. can be cited, but it is not limited thereto.

[0086] Figure 8 Fig. shows an example of a wearable terminal incorporating a battery pack. As Figure 8 shown, the wearable terminal 630 according to the application example is a watch-type terminal and has a battery pack 632 inside it. As the battery pack 632, the battery pack according to the present invention can be applied. The wearable terminal 630 can be worn and used by a user. The wearable terminal 630 can also be a flexible terminal that can be deformed.

[0087] As Figure 9 shown, the wearable terminal 630 according to the application example includes an electronic circuit 631 of an electronic device main body and a battery pack 632. The battery pack 632 is electrically connected to the electronic circuit 631. The wearable terminal 630 has, for example, a structure in which the battery pack 632 can be freely attached and detached by the user. It should be noted that the structure of the wearable terminal 630 is not limited thereto, and it may also have a structure in which the battery pack 632 is built into the wearable terminal 630 so that the user cannot remove the battery pack 632 from the wearable terminal 630.

[0088] When the battery pack 632 is charged, the positive terminal 634A and the negative terminal 634B of the battery pack 632 are respectively connected to the positive terminal and the negative terminal of a charger (not shown). On the other hand, when the battery pack 632 discharges (when the wearable terminal 630 is used), the positive terminal 634A and the negative terminal 634B of the battery pack 632 are respectively connected to the positive terminal and the negative terminal of the electronic circuit 631.

[0089] (Electronic circuit)

[0090] The electronic circuit 631 includes, for example, a CPU (Central Processing Unit), a peripheral logic unit, an interface unit, a storage unit, etc., and controls the whole of the wearable terminal 630.

[0091] (Battery pack)

[0092] The battery pack 632 includes an all-solid battery cell 610 (the all-solid battery 13 in the embodiment) and a charge and discharge circuit 633.

[0093] Description of reference numerals

[0094] 1: Secondary battery; 2: First insulating plate; 3: FPC; 4: Second insulating plate; 10: Battery pack; 101: Metal exterior part; 110: Positive terminal; 120: Negative terminal; 201: Opening (third opening); 202, 203: Openings (fourth opening); 301: Connection part (first connection part); 302, 303: Connection part (second connection part); 321, 322: Connection terminals; 352: Opening (first opening); 363, 364: Openings (second opening).

Claims

1. A battery pack, comprising: Secondary battery; and a circuit board, The secondary battery has: a metal exterior; a first external terminal disposed at the center of an end face of the metal exterior; and a second external terminal disposed so as to surround the first external terminal, The circuit board has: a first connection portion connected to the first external terminal; and a second connection portion connected to the second external terminal, The battery pack is provided with: an insulating portion that insulates the first connection portion and the second connection portion, The first connection portion and the second connection portion are disposed in the same plane.

2. The battery pack according to claim 1, wherein The circuit board is made of an FPC or a metal plate covered with insulation.

3. The battery pack according to claim 1 or 2, wherein The insulating portion is a polyimide film or a non-woven fabric.

4. The battery pack according to claim 1 or 2, wherein The first connection portion has a first opening, The second connection portion has a second opening, The insulating portion has: a third opening disposed at a position corresponding to the first opening; and a fourth opening disposed at a position corresponding to the second opening.

5. The battery pack according to claim 1 or 2, wherein At least a part of a surface of the circuit board opposite to the surface in contact with the insulating portion is covered with another insulating portion different from the insulating portion.

6. The battery pack according to claim 5, wherein The other insulating portion is a polyimide film or a non-woven fabric.

7. The battery pack according to claim 1 or 2, wherein The circuit board has: a connection terminal connected to an external device.

8. The battery pack according to claim 7, wherein The connection terminal and the circuit board are provided on the same substrate.

9. The battery pack according to claim 1 or 2, wherein The metal exterior has a cylindrical shape.

10. An electronic device having the battery pack according to any one of claims 1 to 9.

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