JP2003346756A - Battery device and digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery device that has such an advantage that the power supply loop can be precisely cut off and the safety of the device can be secured when the battery is heated abnormally, and that can be used repeatedly and can be formed in small size, and a digital camera. <P>SOLUTION: The battery device comprises a battery housing part 15 that is installed in an electronic equipment (digital camera 10) driven by a battery B so as to be capable of housing the battery B in free replacement, a contactor 20 that is provided so as to contact the electrode E of the battery B housed in this battery housing part 15 and take out electric energy, and a protection means 30 including a shape-memory alloy wire that separates the above contactor 20 from the electrode E of the battery B by changing the wire length by shape-memory effect, when the temperature of the battery B has surpassed a prescribed value. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery device suitable for battery-driven electronic equipment and a digital camera equipped with the battery device.

[0002]

2. Description of the Related Art In electronic equipment having a battery device,
As shown in FIG. 4, when the batteries B1 to B4 are loaded into the battery accommodating portion 15, for example, if the minute metal pieces 50 and the like are mixed together in the battery accommodating portion, a short circuit occurs between the electrodes due to the minute metal pieces 50 and the like. . For this reason, an excessive current may flow through the short-circuited battery, causing the battery to abnormally generate heat and possibly causing a failure of the electronic device.

[0003] Various countermeasures have been taken to avoid failure of electronic equipment due to abnormal heat generation of the battery (particularly, destruction of important components such as a CCD in a digital camera).

For example, Japanese Patent Application Laid-Open No. 11-179210 discloses that
By soldering the battery contact piece and the load circuit contact arranged in the battery compartment, when an excessive current flows through the battery and the battery contact piece is heated, the above-mentioned soldered portion is melted, and the battery contact piece is melted. A battery chamber with a thermal fuse function, in which a power supply loop is cut off by disconnecting from a load circuit contact, and an apparatus using the same are disclosed.

In Japanese Patent Application Laid-Open No. 8-204366, a shape memory alloy wire is disposed as a temperature detecting means on the back surface of a cover of a battery housing, so that when the battery housing is overheated, the above-mentioned wire is reduced by reducing the wire. There is disclosed a solar cell-equipped device in which the cover is released from tension by a latch claw of the cover, and the cover is opened by a driving force of a spring to cool the battery housing portion by air.

[0006]

Problems to be Solved by the Invention
Battery room with thermal fuse function disclosed in 10
In the apparatus, once the power supply loop is cut by the operation of the thermal fuse function, there is an inconvenience that the apparatus cannot be reused unless a complicated operation for restoring the cut point is restored.

[0007] In the solar cell equipment disclosed in Japanese Patent Application Laid-Open No. 8-204366 in which the battery housing is air-cooled, the cover of the battery housing is opened using a shape memory alloy wire, and the inside of the battery housing is air-cooled. Because of this, there is a problem that the entire device becomes large-scale.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a battery device and a digital camera having the following advantages.

(A) When the battery generates abnormal heat, the power supply loop can be accurately cut off, and the safety of the device can be improved.

(B) It can be used repeatedly.

(C) It can be formed small.

[0012]

Means for Solving the Problems In order to solve the above problems and achieve the object, a battery device and a digital camera of the present invention have the following characteristic configurations. Note that characteristic configurations other than the following will be clarified in the embodiment.

(1) The battery device of the present invention comprises a battery accommodating portion provided in a battery-driven electronic device so as to be capable of accommodating the battery B in a replaceable manner, and the battery accommodating portion accommodated in the battery accommodating portion. A contact provided to take out electric energy by contacting the battery electrode, and when the temperature of the battery exceeds a predetermined value, the wire length is changed by a shape memory effect, and the contact is connected to the electrode of the battery. And a protection means including a shape memory alloy wire deviated from the shape memory alloy wire.

In the above battery device, when the battery temperature exceeds a predetermined temperature, the contact is automatically separated from the battery electrode by the action of the shape memory alloy wire, and the power supply loop is opened to ensure safety. The structure is simpler than that which is powered off by a thermal fuse.

(2) A digital camera according to the present invention includes the battery device described in (1) or the like.

In the above digital camera, CC caused by abnormal heat generation of a camera battery for supplying relatively large electric power.
It is possible to prevent destruction of important parts such as D and other camera failures. In addition, the size and weight of the camera can be maintained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a diagram showing a schematic configuration of a compact digital camera provided with a battery device according to a first embodiment of the present invention. (B) is a perspective view as viewed from the lower left of the camera.

In FIGS. 1A and 1B, reference numeral 10 denotes a compact digital camera, and a photographing lens window 11, a strobe light emission window 12, and a finder front window 1 are provided on the front surface thereof.
3, etc. are provided. A release button 14 is provided on the upper surface of the camera 10.

Inside the digital camera 10, there is provided a battery accommodating section 15 provided so that a plurality of (four in the present embodiment) batteries B (B1 to B4) can be exchangeably loaded. The batteries B1 to B4 are housed in parallel with the directions of the positive electrode and the negative electrode being alternately reversed.

The battery housing 15 has an opening K for inserting and removing a battery on the bottom surface of the digital camera 10. The opening K can be closed and opened by an opening / closing lid 16. Two conductive pieces 17 and 18 are provided on the inner surface of the opening / closing lid 16.

When the opening / closing lid 16 is closed, the conductive piece 17 comes into contact with the electrodes E1 and E2 at the outer ends of the batteries B1 and B2 housed in the battery housing portion 15 to conduct between the electrodes. Similarly, when the opening / closing lid 16 is closed, the conductive piece 18 comes into contact with the electrodes E3 and E4 at the outer ends of the batteries B3 and B4 to conduct between the electrodes.

FIG. 2 is a diagram showing a detailed configuration of the battery device.
(A) is a schematic sectional view of the battery device viewed from the front of the camera,
(B) is a cross-sectional view taken along line bb of (a), (c) is (b)
FIG. 5 is a sectional view taken along line cc of FIG.

As shown in FIGS. 2A, 2B and 2C,
In the innermost part of the battery housing part 15, three contacts 21 and
2 and 23 are provided in such a manner as to be held by a contact holding plate 31 of an urging means 30 described later.

The contact 21 is connected to the electrode E at the inner end of the battery B1.
Touch 1. The contact 22 makes common contact with the electrodes E2 and E3 at the inner ends of the batteries B2 and B3 to conduct between the electrodes.
The contact 23 contacts the electrode E4 at the inner end of the battery B4.

Thus, the batteries B1 to B4
Is accommodated in a predetermined polarity and the opening / closing lid 16 is closed,
The contacts 21, 22, 23 and the conductive pieces 17, 18 come into contact with the respective electrodes E1 to E4 of the batteries B1 to B4 accommodated. As a result, electric energy is extracted between the contacts 21 and 23 and can be supplied to the load 43 via the leads 41 and 42.

When an excessive current flows through the battery B loaded in the battery housing 15 for some reason, the battery B generates abnormal heat and causes a camera failure. In order to avoid a camera failure due to such abnormal heating of the battery B, the present battery device includes a protection unit 30.

The protection means 30 includes the batteries B1 to B4
When any one of the temperatures exceeds a predetermined value, the wire length is changed by the shape memory effect to separate the contacts 21 to 23 from the electrodes E1 to E4 at the inner ends of the batteries B1 to B4. It is configured to include the alloy wire 33.

That is, the protection means 30 is
Urging means 31 for urging the batteries 23 to 23 away from the electrodes E1 to E4 of the batteries B1 to B4, and the urging means 31
Contacts 21 to 23 are opposed to the electrodes E1 to E4
The locking mechanism 32 for locking the contacts 21 to 23 and the locking of the contacts 21 to 23 by the locking mechanism 32 are used to maintain the state of contact with the batteries B1 to B4 at a predetermined value. And a shape memory alloy wire 33 that is pulled off when the distance exceeds the limit.

The urging means 31 is formed in a strip shape, one end of which is rotatably supported by a shaft.
Contact holding plate 31a provided so as to collectively hold 23
And a spring 31b for urging the contact holding plate 31a to rotate in a direction away from the electrodes E1 to E4.
Consists of

The locking mechanism 32 has a base end provided with a shaft support 32a.
Locking portion 3 which is rotatably supported at its end and whose tip is bent into an L-shape.
It has a locking lever 32c of 2b.

Further, the shape memory alloy wire 33 is provided so that the locking lever 32c can be turned from the locking position P1 to the non-locking position P2 shown in FIG. 3 by a change in the wire length due to the shape memory effect. ing. That is, as shown in FIG. 2C, the shape memory alloy wire 33 is attached to the back side of the wall 15 w of the battery housing 15, and at least a part thereof is attached to the battery housing 15. The plurality of batteries B <b> 1 to B <b> 4 housed in parallel are wired so as to meander via the folded portion U along the longitudinal direction. The folded portion U can be transported and guided by guide posts 34a, 34b to 34i formed of, for example, columnar bosses. The transformation start temperature of the shape memory alloy wire 33 is set to, for example, about 70 ° C.

FIG. 3 is a diagram showing an operation state of the battery device when the battery generates abnormal heat. Hereinafter, the operation of the battery device of the present embodiment will be described with reference to FIGS. 2 and 3 as appropriate.
In the steady state, as shown in FIG.
Since the contact holding plate 31a is locked by the locking lever 32c, the contacts 21 to 23 are stably in contact with the electrodes E1 to E4. Therefore, electric energy is extracted between the contacts 21 and 23, and this is
The electric power is supplied to the load 43 via the first and second terminals 42.

When the battery B generates abnormal heat for some reason, the heat is transmitted to the shape memory alloy wire 33. When the temperature of the shape memory alloy wire 33 exceeds the transformation start temperature,
The shape memory alloy wire 33 changes (shrinks) the wire length by the shape memory effect. Therefore, as shown in FIG. 3, the locking lever 32c is pulled by the tip of the shape memory alloy wire 33 and rotates. As a result, the locking portion 3 of the locking lever 32c that has locked the contact holding plate 31a until then.
2b is pulled off from the contact holding plate 31a. Therefore, the holding plate 31a rotates in a direction away from the electrodes E1 to E4 by the urging force of the spring 31b. Thus, the contacts 21 to 23 held by the holding plate 31a
Are in a state of being surely separated from the electrodes E1 to E4.

As described above, when any one of the batteries B1 to B4 exceeds a predetermined temperature, that is, the transformation start temperature of the shape memory alloy wire 33, the contacts 21, 22, and 23 are automatically turned into electrodes by the action of the shape memory alloy wire 33. Separated from E1 to E4, the power supply loop is opened and safety is achieved.

(Characteristics of Embodiment) [1] The battery device shown in the embodiment is provided in an electronic device (digital camera 10) driven by the battery B so that the battery B can be exchangeably accommodated. Battery compartment 15
A contact 20 provided so as to contact the electrode E of the battery B housed in the battery housing portion 15 to take out electric energy; and a shape when the temperature of the battery B exceeds a predetermined value. And a protection means 30 including a shape memory alloy wire 33 for changing the wire length by the memory effect and separating the contact 20 from the electrode E of the battery B.

In the battery device described above, when the battery B exceeds a predetermined temperature, the contact 20 is automatically separated from the battery electrode E by the action of the shape memory alloy wire 33, and the power supply loop is opened to ensure safety. . In addition, the structure is simpler than that of power-off by a thermal fuse.

[2] The battery device according to the embodiment is the battery device according to the above [1], wherein the protection means 30
A biasing means 31 for biasing the contact 20 in a direction to separate from the electrode E of the battery B, and the contact 20 contacting the electrode E against the biasing force of the biasing means 31. Locking mechanism 32 for locking the contact 20 so as to maintain the contact state, and a shape for tripping the locking of the contact 20 by the locking mechanism 32 when the temperature of the battery B exceeds a predetermined value. And a memory alloy wire 33.

In the above-described battery device, the contact 20 is stably brought into contact with the electrode E by the locking mechanism 32 in a steady state. Also, when the battery B is abnormally heated, the locking mechanism 32 is pulled off by the shape memory alloy wire 33.
The contact 20 is surely separated from the electrode E by the urging force of the urging means 31.

[3] The battery device according to the embodiment is the battery device according to [2], wherein the urging means 31
Includes a movable contact holding plate 31a for holding the contact 20 (including rotation, linear movement, etc.) and a spring 31b for urging the contact holding plate 31a to move away from the electrode E. It is characterized by containing.

The above battery device has a simple structure and is easy to manufacture.

[4] The battery device according to the embodiment is the battery device according to [2] or [3], wherein the locking mechanism 32 is rotatably supported at a base end. , A locking lever 32c having a locking portion 32b with an L-shaped tip.
And the locking lever 32c is
c from the locking position P1 to the non-locking position P by changing the wire length of the shape memory alloy wire 33 having one end connected to
It is characterized in that it is provided so as to rotate to 2.

In the above battery device, the locking lever 32
Since c can be rotated with a relatively small force, the unlocking force by the shape memory alloy wire 33 may be relatively small.

[5] The battery device according to the embodiment is the battery device according to any one of [1] to [4], wherein at least a part of the shape memory alloy wire 33 is formed in the longitudinal direction of the battery B. It is characterized by being wired along the direction.

In the above battery device, the shape memory alloy wire 33 is arranged in such a manner that the abnormal heat generation of the battery B can be detected with the highest sensitivity, so that the detection accuracy is high.

[6] The battery device according to the embodiment is the battery device according to [5], wherein at least a part of the shape memory alloy wire 33 is provided in parallel with the battery housing 15. It is characterized in that it is wired so as to meander via a folded portion U along the longitudinal direction of the plurality of batteries B1 to B4 to be accommodated.

In the above battery device, any of the batteries B1 to B1
Even if B4 generates abnormal heat, it can be accurately detected.

[7] The battery device according to the embodiment is the battery device according to the above [6], wherein the folded portion U
Are provided so as to be transported and guided by the guide posts 34a, 34b to 34i.

In the above battery device, the shape memory alloy wire 33 is stretched by the guide posts 34a, 34b to 34i so that the sliding friction resistance in the longitudinal direction is small and there is no slack. The change in the wire length generated in the step (1) is accurately transmitted to the tip of the wire.

[8] The battery device according to the embodiment is the battery device according to the above [5] or [6], wherein the shape memory alloy wire 33 is connected to the wall 1 of the battery housing 15.
It is characterized by being attached to the back side of 5w.

In the above battery device, since the shape memory alloy wire 33 is not exposed in the battery accommodating portion 15, there is no possibility that the wire 33 is erroneously damaged at the time of battery replacement or the like.

[9] The digital camera shown in the embodiment is provided with the battery device according to any one of the above [1] to [8].

In the digital camera 10, it is possible to prevent camera failure due to abnormal heat generation of the camera battery B that supplies relatively large power. Further, the size and weight of the camera 10 can be kept from being impaired.

(Modifications) The battery device and the digital camera described in the embodiment include the following modifications.

The guide posts 34a, 34b to 34i are formed of small pulleys.

The battery device described in the embodiment is applied to a portable personal computer, a PDA, a movie, and the like.

[0056]

According to the present invention, a battery device and a digital camera having the following functions and effects can be provided.

(A) Since the contact for extracting electric energy is separated from the electrode of the battery by the function of the shape memory alloy wire disposed close to the battery, when the battery abnormally generates heat, power is supplied. The loop can be properly interrupted, and the safety of the device can be improved.

(B) Since the shape memory alloy wire does not melt and disappear like solder and a thermal fuse, it can be restored to its current state, and can be used repeatedly.

(C) Since the shape memory alloy wire is a thin linear body, it can be formed in a small size.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a compact digital camera provided with a battery device according to a first embodiment of the present invention;
(A) is a perspective view as viewed from the front right of the camera, and (b) is a perspective view as viewed from the lower left of the camera.

FIGS. 2A and 2B are diagrams showing a detailed configuration of the battery device according to the first embodiment of the present invention, wherein FIG. 2A is a schematic sectional view of the battery device as viewed from the front of the camera, and FIG. b line sectional view,
(C) is a sectional view taken along line cc of (b).

FIG. 3 is a schematic sectional view showing an operation state of the battery device according to the first embodiment of the present invention when the battery is abnormally heated.

FIG. 4 is a schematic sectional view of a battery accommodating portion for explaining a problem in a conventional battery device.

[Explanation of symbols]

10. Compact digital camera 15: Battery compartment 16: Open / close lid 17, 18 ... conductive piece 20 (21, 22, 23) ... contact 30 ... Protection means 31 ... Biasing means 31a: Contact holding plate 31b: Spring 32: locking mechanism 32a: shaft support 32b: locking portion 32c: locking lever 33 ... Shape memory alloy wire 34a, 34b-34i ... guide post 41, 42 ... Lead wire B (B1 to B4): Battery E (E1 to E4) ... electrode

Claims (9)

[Claims] An electronic device driven by a battery is provided with a battery accommodating portion provided so as to be capable of accommodating the battery in an exchangeable manner, and an electric energy in contact with an electrode of the battery accommodated in the battery accommodating portion. And a shape memory alloy wire that, when the temperature of the battery exceeds a predetermined value, changes the wire length by a shape memory effect and separates the contact from the electrode of the battery. A battery device comprising: a protection unit. 2. The battery according to claim 1, wherein said protection means comprises: an urging means for urging said contact in a direction to separate said contact from an electrode of said battery; A locking mechanism for locking the contact so as to maintain the contact state, and a shape memory alloy wire for releasing the locking of the contact by the locking mechanism when the temperature of the battery exceeds a predetermined value. The battery device according to claim 1, comprising: 3. The urging means includes a movable contact holding plate for holding the contact, and a spring for urging the contact holding plate to move away from the electrode. The battery device according to claim 2, wherein 4. The locking mechanism according to claim 1, further comprising a locking lever having a base end rotatably supported by the shaft and a distal end serving as a locking portion bent in an L-shape. 4. The device according to claim 2, wherein the shape memory alloy wire having one end connected to a stop lever is provided so as to rotate from a locked position to a non-locked position by a change in a wire length. 5. Battery device. 5. The battery device according to claim 1, wherein at least a part of the shape memory alloy wire is wired along a longitudinal direction of the battery. . 6. At least a part of the shape memory alloy wire is wired so as to meander via a folded portion along a longitudinal direction of a plurality of batteries housed in parallel in the battery housing portion. The battery device according to claim 5, wherein: 7. The battery device according to claim 6, wherein the folded portion is provided so as to be transported and guided by a guide post. 8. The battery device according to claim 5, wherein the shape memory alloy wire is attached to a back side of a wall of the battery accommodating portion. 9. A digital camera comprising the battery device according to claim 1.