Patent Description:
Various portable electronic devices (hereinafter may also be referred to as the "mobile devices"), such as mobile phones typical ones of which are smartphones, tablet computers have been known. A problem of the mobile devices to be solved is preventing internal components from being damaged by an impact of the drop.

A secondary battery typical one of which is a lithium-ion secondary battery is installed in the mobile devices. There is a possibility that such a secondary battery is also damaged since the secondary battery moves through a space within a mobile device due to an impact of a drop of the mobile device, and the secondary battery collides with an internal wall or the like within the mobile device. Therefore, measures have been taken to decrease damage to the secondary battery due to an impact of a drop of the mobile device.

For example, Patent Document <NUM> discloses a battery cell applicable to portable electronic devices and including a battery element contained in a packaging material including a laminate film. The battery cell includes a resin layer inserted on at least one side of the battery element, and separating the battery element from the packaging material. In the battery cell disclosed in Patent Document <NUM>, an impact absorbing effect of the resin layer protects the battery element from external impacts.

However, in the battery cell disclosed in Patent Document <NUM>, the resin layer for absorbing an impact is added between the battery element and the packaging material. The battery cell disclosed in Patent Document <NUM> increases a size of a battery pack. Mobile devices highly need to be downsized. Therefore, preferably, an increase in size of battery packs is avoided as much as possible.

Therefore, the present disclosure proposes a battery pack and an electronic device that are novel and improved, suppress an increase in size of a battery pack, and decrease damage to a battery element due to an external impact.

As described above, the present disclosure suppresses an increase in size of a battery pack, and can decrease damage to a battery element due to an external impact.

Note that the above effects are not necessarily limiting. In addition to or instead of the above effects, any of effects described in the present specification or other effects that can be grasped from the present specification may be obtained.

Hereinafter, a preferred exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in the present specification and the drawings, components having substantially the same function and configuration are denoted by the same reference numeral, and redundant description is omitted.

Note that the description will be made in the following order.

In the present specification, a structure that includes a battery element and has not been coated with a laminate sheet is referred to as a battery cell. The battery cell connected to a circuit board and to which a laminate sheet, a top holder, and a bottom holder are attached is referred to as a battery pack. Furthermore, a side of the battery pack and the battery cell from which a positive terminal and a negative terminal protrude is referred to as a top portion. A side of the battery pack and the battery cell facing the top portion is referred to as a bottom portion. The other portions of the battery pack and the battery cell are referred to as side portions. Moreover, a length in a direction of both the side portions may be referred to as a width. A length in a direction of the top portion-the bottom portion may be referred to as a height.

First, a basic-configuration example of a battery pack according to an exemplary embodiment of the present disclosure will be described. In the following description, basic aspects of components of the battery pack according to the present exemplary embodiment will be described. The components of the battery pack according to the present exemplary embodiment are also included by conventional battery packs. <FIG> is a perspective view illustrating an appearance of a battery pack <NUM>. <FIG> is an exploded perspective view illustrating a configuration example of the battery pack <NUM>.

The battery pack <NUM> according to the present exemplary embodiment is, for example, a prismatic or flat lithium-ion secondary battery pack. The battery pack <NUM> is installed in a portable electronic device. The electronic device may be configured so that a user cannot attach and detach the battery pack <NUM>, or may be configured so that a user can attach and detach the battery pack <NUM>.

Examples of the electronic device include a mobile phone, such as a smartphone, a tablet computer, a notebook personal computer, a personal digital assistant (PDA), a display device, a navigation system, an electronic book, an electronic dictionary, a music player, and the like. However, the electronic device is not limited to these examples.

As illustrated in <FIG>, the battery pack <NUM> includes a battery cell <NUM>, a top holder <NUM>, a bottom holder <NUM>, a circuit board <NUM>, and a laminate sheet <NUM>. The battery cell <NUM> includes a battery element coated with a laminate film, such as a soft aluminum sheet or the like, for example, and electrically connected to the circuit board <NUM>. The laminate sheet <NUM> is wound around and adhered to a periphery of the battery cell <NUM>. Openings are formed at a top portion and a bottom portion of the battery cell <NUM> around which the laminate sheet <NUM> is wound. The top holder <NUM> is attached to the opening at the top portion. The bottom holder <NUM> is attached to the opening at the bottom portion.

Note that an electrically insulating adhesive sheet or the like for fixing the circuit board <NUM> and the top holder <NUM> is not illustrated in <FIG>.

The battery cell <NUM> includes the battery element including a positive terminal 18a and a negative terminal 18b. The positive terminal 18a and the negative terminal 18b are coated with an insulating insulating sheet (not illustrated). However, portions of the positive terminal 18a and the negative terminal 18b that are connected to the circuit board <NUM> are not coated.

<FIG> is a perspective view illustrating a configuration example of a battery element <NUM> constituting the battery cell <NUM>. The battery element <NUM> is a laminate that includes a positive electrode, a separator, a negative electrode, and a separator that are laminated in this order. The battery element <NUM> of the battery pack <NUM> according to the present exemplary embodiment is a wound battery element that includes a wound laminate that has a shape like a band. The positive terminal 18a is connected to the positive electrode of the battery element <NUM>. The negative terminal 18b is connected to the negative electrode of the battery element <NUM>.

The battery element <NUM> is contained in a laminate film (not illustrated), such as a soft aluminum sheet. The battery cell <NUM> is formed in a shape like a flat thin plate to cope with downsizing or thinning of electronic devices. Such a battery element <NUM> may be a known battery element.

The circuit board <NUM> is disposed on the top portion of the battery cell <NUM> that has a shape like a plate. The circuit board <NUM> is connected to the positive terminal 18a and the negative terminal 18b of the battery element <NUM>. On the circuit board <NUM>, a temperature detection element, a fuse, and a thermal sensitive resistor that are not illustrated are mounted, for example. Furthermore, the circuit board <NUM> is connected to a flexible circuit board <NUM> connected to a device main body of an electronic device.

The top holder <NUM> is attached to an end of the top portion of the battery cell <NUM>. The battery cell <NUM> and the top holder <NUM> that is disposed at, for example, the end of the top portion of the battery cell <NUM> are wrapped and fixed with the laminate sheet <NUM>.

The circuit board <NUM> is held in the top holder <NUM>. The top holder <NUM> has an opening 11a at a position corresponding to a position of the flexible circuit board <NUM> connected to the circuit board <NUM>. The flexible circuit board <NUM> protrudes outside through the opening 11a.

The bottom holder <NUM> is attached to an end of the bottom portion of the battery cell <NUM>. The battery cell <NUM> and the bottom holder <NUM> that is disposed at, for example, the end of the bottom portion of the battery cell <NUM> are wrapped and fixed with the laminate sheet <NUM>. Moreover, the bottom holder <NUM> illustrated in <FIG> is fixed to the battery cell <NUM> with an adhesive <NUM>.

Note that <FIG> schematically illustrates configurations of the top holder <NUM> and the bottom holder <NUM>.

The laminate sheet <NUM> has a substantially rectangular shape and is adhered to the battery cell <NUM> such that the laminate sheet <NUM> wraps the battery cell <NUM>. The laminate sheet <NUM> is adhered around the battery cell <NUM> with an adhesive layer. The laminate sheet <NUM> is a protective sheet for protecting the battery cell <NUM>. The laminate sheet <NUM> may have strength higher than a laminate sheet including resin. Therefore, the battery cell <NUM> is protected from external impacts. The laminate sheet <NUM> may be, for example, a laminate that includes a hard aluminum layer on both surfaces of which an electrically insulating resin layer is laminated. The resin layers are layers including, for example, a polyethylene terephthalate (PET) resin.

Impact absorbing structures of the battery pack <NUM> according to the present exemplary embodiment that are formed at the top holder <NUM> and the bottom holder <NUM> will be described.

As described above, in the battery pack <NUM>, the battery element <NUM> includes a wound laminate that has a shape like a band. Ends of the laminate that has a shape like a band in a width direction of the laminate are at a top portion and a bottom portion. Therefore, if an impact is applied to the battery pack <NUM> in a direction of the top portion or the bottom portion, an end of the battery element <NUM> is likely to be damaged. For example, there is a possibility that deformation of an end of the battery element <NUM> damages the separator, and a short circuit occurs between the positive electrode and the negative electrode.

To prevent such damage, the top holder <NUM> attached to an end of the top portion of the battery cell <NUM> is formed integrally with an impact absorbing structure. The bottom holder <NUM> attached to an end of the bottom portion of the battery cell <NUM> is formed integrally with an impact absorbing structure. The impact absorbing structures decrease an impact of a drop or the like.

<FIG> is a schematic view illustrating a structure within an electronic device <NUM> in which the battery pack <NUM> is installed. In <FIG>, a back cover is removed from the electronic device <NUM>. The electronic device <NUM> illustrated in <FIG> is a thin smartphone as an example. The battery pack <NUM> is disposed such that a direction of the top portion-the bottom portion of the battery pack <NUM> is along a longitudinal direction of the electronic device <NUM>. The battery pack <NUM> is installed in the electronic device <NUM>. The battery pack <NUM> is electrically connected to a device main body through connection terminals of the flexible circuit board <NUM>.

The battery pack <NUM> is positioned at a predetermined position. Between the battery pack <NUM> and components around the battery pack <NUM>, a space is formed within a predetermined range of a tolerance. Furthermore, the battery pack <NUM> is fixed to the inside of the device main body of the electronic device <NUM> with a double-sided tape <NUM>. In the example illustrated in <FIG>, the battery pack <NUM> is fixed to the back cover (not illustrated) with the double-sided tape <NUM>. Therefore, in a case where a relatively light impact is applied to the electronic device <NUM>, the battery pack <NUM> is less likely to become out of position within the electronic device <NUM>.

However, in a case where a strong impact is applied to the electronic device <NUM>, the battery pack <NUM> may move in the electronic device <NUM>, and may collide with an inner wall of the electronic device <NUM>, other electronic components, or the like, and thus the battery element <NUM> may be damaged. To decrease such damage to the battery element <NUM>, the impact absorbing structures are formed at the top holder <NUM> and the bottom holder <NUM>.

<FIG> is a schematic view illustrating a state where the laminate sheet <NUM> is removed from the battery pack <NUM> according to the present exemplary embodiment. <FIG> is a schematic view illustrating one configuration example of the bottom holder <NUM>. Note that since the impact absorbing structure of the top holder <NUM> can have a configuration similar to the impact absorbing structure of the bottom holder <NUM>, only the configuration of the bottom holder <NUM> will be described here.

The bottom holder <NUM> includes a first member <NUM> and a second member <NUM> that are arranged along a direction being away from an end of the bottom portion of the battery cell <NUM>. The bottom holder <NUM> includes an elastic-deformation portion <NUM> disposed between the first member <NUM> and the second member <NUM>. That is, the impact absorbing structure of the bottom holder <NUM> illustrated in <FIG> has an elastic structure. Both ends of the elastic-deformation portion <NUM> are connected to both ends of the second member <NUM>. The elastic-deformation portion <NUM> is curved and protrudes toward the first member <NUM>. The center of the elastic-deformation portion <NUM> is connected to the first member <NUM>.

The bottom holder <NUM> may be an integrally molded product including, for example, a resin material. Alternatively, the bottom holder <NUM> may be a molded product that includes the first member <NUM>, the second member <NUM>, and the elastic-deformation portion <NUM> that are joined together.

The first member <NUM> is joined to an end of the bottom portion of the battery cell <NUM> with an adhesive or the like (not illustrated). The second member <NUM> is at an end of the bottom portion of the battery pack <NUM>. For example, the first member <NUM> and the elastic-deformation portion <NUM> may be completely coated with the laminate sheet <NUM>, and part of the second member <NUM> need not to be coated with the laminate sheet <NUM> and may be exposed.

<FIG> is an illustration illustrating states of the bottom holder <NUM> that is deforming when the electronic device <NUM> drops while the bottom portion of the battery pack <NUM> is facing downward.

If the battery pack <NUM> moves downward due to an impact of a drop of the electronic device <NUM>, the elastic-deformation portion <NUM> deforms such that a distance between the first member <NUM> and the second member <NUM> of the bottom holder <NUM> becomes shorter. Therefore, at least part of the impact is absorbed, and the impact applied to the battery cell <NUM> is decreased.

A degree to which the elastic-deformation portion <NUM> of the impact absorbing structure of such a bottom holder <NUM> bends can be adjusted by changing a height of the elastic-deformation portion <NUM>, or changing a thickness of a portion that constitutes the elastic-deformation portion <NUM>. The height of the elastic-deformation portion <NUM> corresponds to a distance between the first member <NUM> and the second member <NUM>. With this arrangement, a degree to which an impact is absorbed by the bottom holder <NUM> can be adjusted.

In <FIG>, a ratio of a vertical length to a lateral length is increased to allow the configuration of the bottom holder <NUM> to be easily understood. In a case of the battery pack <NUM> for smartphones, for example, preferably, a width (lateral length) of the bottom holder <NUM> is approximately <NUM>, and a height (vertical length) of the bottom holder <NUM> is approximately <NUM>. In a case where a height of the bottom holder <NUM> is approximately <NUM>, the height is equal to a height of conventional bottom holders. Therefore, an increase in size of the battery pack <NUM> can be suppressed.

The configuration example of the battery pack <NUM> according to the present exemplary embodiment has been described above. However, impact absorbing structures of the top holder <NUM> and the bottom holder <NUM> of the battery pack <NUM> according to the present exemplary embodiment are not limited to the above example. Hereinafter, variations of the impact absorbing structures of the top holder <NUM> and the bottom holder <NUM> will be described.

<FIG> is a schematic view illustrating a bottom holder 13A according to a first variation. In the bottom holder 13A according to the first variation, a resin material <NUM> is filled in a space between the elastic-deformation portion <NUM> and the second member <NUM> of the bottom holder <NUM> described in the above exemplary embodiment. Such a resin material <NUM> functions as an adjusting portion that adjusts a degree to which an impact is absorbed.

In an example illustrated in <FIG>, the resin material <NUM> is filled in the whole space between the elastic-deformation portion <NUM> and the second member <NUM>. However, a resin material may be filled in part of the space. The degree to which an impact is absorbed by the bottom holder 13A can be adjusted by filling the resin material that has elasticity in the space between the elastic-deformation portion <NUM> and the second member <NUM>.

Note that an impact absorbing structure of the top holder <NUM> can have a configuration similar to the impact absorbing structure of the bottom holder <NUM> according to the first variation.

<FIG> is a schematic view illustrating a bottom holder 13B according to a second variation. The bottom holder 13B according to the second variation does not include the first member <NUM> of the bottom holder <NUM> described in the above exemplary embodiment, and includes the elastic-deformation portion <NUM> on the second member (base member) <NUM>. Since the bottom holder 13B according to the second variation does not include the first member <NUM>, a height (length in a vertical direction in the drawing) of the bottom holder 13B becomes smaller. An increase in size of the battery pack <NUM> can be further suppressed.

Note that similarly as the first variation, a degree to which an impact is absorbed by the bottom holder 13B in the second variation may be adjusted by filling a resin material that has elasticity in a space between the elastic-deformation portion <NUM> and the second member <NUM>. Furthermore, an impact absorbing structure of the top holder <NUM> can have a configuration similar to the impact absorbing structure of the bottom holder 13B according to the second variation.

<FIG> is a schematic view illustrating a top holder 11A according to a third variation. An elastic-deformation portion <NUM> of the top holder 11A according to the third variation is disposed between a first member <NUM> and a second member <NUM>. The elastic-deformation portion <NUM> is different from the elastic-deformation portion <NUM> of the bottom holder <NUM> described in the above exemplary embodiment. In the top holder 11A according to the third variation, the first member <NUM> and the second member <NUM> are connected to each other by elastic-deformation portions 165a, 165b that are at left and right end sides, respectively.

Shapes of cross sections of the two elastic-deformation portions 165a, 165b are each V-shaped. The two elastic-deformation portions 165a, 165b are disposed such that bent portions that have V-shaped cross sections each face outward. Of the top holder 11A according to the third variation, at least the elastic-deformation portions 165a, 165b include a resin material that has been molded into the elastic-deformation portions 165a, 165b. Therefore, if the battery pack <NUM> moves upward in the drawing due to an impact of a drop of the electronic device <NUM>, the elastic-deformation portion <NUM> deforms such that a distance between the first member <NUM> and the second member <NUM> of the top holder 11A becomes shorter. Therefore, at least part of the impact is absorbed, and the impact applied to the battery cell <NUM> is decreased.

A stroke length of the elastic-deformation portion <NUM> at a time of deformation is longer than a stroke length of the impact absorbing structure of the bottom holder <NUM> described in the above exemplary embodiment. The top holder 11A according to the third variation absorbs a more impact. Furthermore, in the top holder 11A according to the third variation, a space surrounded by the first member <NUM>, the second member <NUM>, and the elastic-deformation portions 165a. 165b is large. Therefore, components including the circuit board <NUM> and the like are arranged in the space. The stroke length at a time of elastic deformation increases, and an increase in size of the battery pack <NUM> can be suppressed.

Note that similarly as the first variation, a degree to which an impact is absorbed by the top holder 11A in the third variation may be adjusted by filling a resin material that has elasticity in a space between the first member <NUM>, the second member <NUM>, and the elastic-deformation portions 165a, 165b. Furthermore, an impact absorbing structure of the bottom holder <NUM> can have a configuration similar to the impact absorbing structure of the top holder 11A according to the third variation.

As described above, the battery pack <NUM> according to the present exemplary embodiment does not include additional components. The top holder <NUM> and the bottom holder <NUM> that are components constituting the battery pack <NUM> include the impact absorbing structures. Therefore, a possibility that downsizing of portable electronic devices is hindered is decreased, and an impact due to a drop or the like can be decreased.

Furthermore, an elastic force or an impact absorbing ability of the battery pack <NUM> according to the present exemplary embodiment can be adjusted by changing type of the resin material that the top holder <NUM> and the bottom holder <NUM> include, or by changing form of the elastic-deformation portion <NUM>. Therefore, the battery pack <NUM> can be applied not only to smartphones, but also to various portable electronic devices.

As described above, the preferred exemplary embodiment of the present disclosure has been described in detail with reference to the accompanying drawings, but the technical scope of the present disclosure is not limited to such examples. It is apparent that those having ordinary knowledge in the technical field of the present disclosure can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that the various changes or modifications also naturally belong to the technical scope of the present disclosure.

For example, in the battery pack <NUM> according to the above exemplary embodiment, the impact absorbing structures are formed at both the top holder <NUM> and the bottom holder <NUM>. The top holder <NUM> and the bottom holder <NUM> are arranged near ends of the laminate in a width direction of the laminate. The laminate constitutes the battery element <NUM> and has a shape like a band. However, the technology of the present disclosure is not limited to such an example. The impact absorbing structure may be formed at only one of the top holder <NUM> and the bottom holder <NUM>.

Furthermore, in the battery pack <NUM> according to the above exemplary embodiment, a battery element including a laminate that has a shape like a band is used as the battery element <NUM>. However, the technology of the present disclosure is not limited to such an example. The battery element <NUM> may be a layered battery element that includes a positive electrode, a separator, a negative electrode, and a separator that are repeatedly laminated. In this case, ends of the positive electrode and the negative electrode exist at a whole periphery of the battery element <NUM>. Therefore, holders that include impact absorbing structures may be disposed not only at the top portion and the bottom portion, but also at an appropriate end(s) of the periphery of the battery cell <NUM>. Therefore, even in a case where an electronic device drops in any direction, an impact of the drop is decreased. Damage to the battery element <NUM> can be suppressed.

Claim 1:
A battery pack (<NUM>) comprising:
a battery cell (<NUM>) including a battery element (<NUM>);
at least one holder (11A) facing an end of the battery element (<NUM>); and
an impact absorbing structure (<NUM>) formed at the holder (11A);
wherein the impact absorbing structure (<NUM>) includes an elastic-deformation portion disposed at the holder (11A);
the holder (11A) includes a first member (<NUM>) and a second member (<NUM>);
the elastic-deformation portion (<NUM>) is disposed between the first member (<NUM>) and the second member (<NUM>) closer to the end of the battery cell (<NUM>) than the second member (<NUM>) is disposed; and
the elastic-deformation portion (<NUM>) deforms upon impact such that a distance between the first member (<NUM>) and the second member (<NUM>) of the holder (11A) becomes shorter; wherein
the elastic-deformation portion (<NUM>) comprises two elastic-deformation portions (165a, 165b) at left and right sides connecting the first member (<NUM>) and the second member (<NUM>), each of the two elastic-deformation portions including a resin material and having a V-shaped cross section facing outwards; and
a space surrounded by the first member (<NUM>), second member (<NUM>) and two elastic-deformation portions (165a, 165b) comprises a circuit board (<NUM>) of the battery pack (<NUM>).