JP3588343B2 - Battery pack - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery pack used as a power source for electronic devices and the like.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a battery pack in which one or a plurality of batteries are combined and housed in a resin outer case has been used for electronic devices.
Inside the battery pack, besides the battery, a protection circuit for preventing overcharge and overdischarge during charging and discharging, and lead wiring for electrically connecting the battery to an external input / output terminal or a protection circuit, etc. It is stored. The protection circuit is mounted on a printed circuit board, and a lead plate or a lead wire is used for lead wiring. These printed circuit boards and lead wires are arranged directly on the periphery of the battery, or are fixedly arranged on a resin holder along the shape inside the outer case of the battery pack.
[0003]
[Problems to be solved by the invention]
By the way, an electronic device such as a mobile phone is often used outdoors, and may be exposed to rainwater or immersed in a drink on a table when used under rainy weather. In such a case, the battery pack used as a power supply for the electronic device may be exposed to moisture such as rainwater and drinks along with the device, and water may enter from a portion of the external input / output terminal exposed on the surface of the outer case. Sometimes. In a battery pack in which the outer case of the battery pack is cracked due to a drop or the like, water may enter from the cracked portion.
[0004]
If moisture enters the inside of the battery pack, moisture may adhere to the protection circuit and lead wiring, causing a short circuit and destroying the protection circuit and the like. If the battery is left in a short-circuit state and the over-discharge state continues, the battery may deteriorate significantly and cause liquid leakage. In addition, if water adheres to the terminal portion of the battery, it may cause corrosion and may further easily cause liquid leakage.
[0005]
In order to avoid such a situation, Japanese Patent Application Laid-Open No. 11-144699 discloses a technique of using a submergence determination seal to allow a user of a device to recognize the entry of water.
However, according to the technology disclosed above, the user of the device can recognize the intrusion of water into the battery pack when the battery pack is removed from the device and the submergence determination seal is checked, and the user of the device is instructed by the occurrence of inundation. Until the recognition, a short circuit occurs in the protection circuit and wiring inside the battery pack.
[0006]
In order to solve the above problems, the present invention provides a battery pack that does not cause a short circuit in a circuit and wiring between a battery and an external input / output terminal even when water is generated in the battery pack. The purpose is to.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a battery pack of the present invention has a waterlogging sensor that detects moisture that has entered the interior of an outer case, and a control circuit that outputs a connection cutoff signal based on the waterlogging detection result of the waterlogging sensor. A connection cutoff element that receives a connection cutoff signal from the control circuit and cuts off the electrical connection between the battery and the external input / output terminal, and the immersion detection sensor is provided on an inner surface of the outer case, It is characterized by being formed by applying a conductive paint .
[0008]
In this battery pack, when moisture enters the inside, the control circuit outputs a connection cutoff signal based on the result of water detection detected by the water detection sensor, receives the signal, and connects and disconnects the battery with the external input / output device. Since the electrical connection between the battery and the external input / output terminal is interrupted, even if the circuit and wiring between the battery and the external input / output terminal become conductive due to moisture, the connection disconnecting element and the external input / output terminal are disconnected. Short circuits can be prevented from occurring in circuits and wiring between output terminals.
[0009]
The water immersion sensor is preferably a pair of electrodes formed on the inner surface of the outer case while maintaining a gap therebetween.
Further, it is preferable that the pair of electrodes is arranged so as to be distributed over at least one of the inner surfaces of the outer case.
Specifically, it is preferable that each of the electrodes has a comb shape, and is arranged such that a convex portion of one electrode is positioned in a concave portion of the other electrode. This is because if the pair of electrodes is used as a waterlogging sensor, when water adheres to the gap between the electrodes, the electrodes are brought into conduction and waterlogging is detected. That is, in the region where the gap is provided, it is possible to accurately detect the intrusion of moisture that causes a short circuit in the internal wiring and circuit.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The structure of the battery pack according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is an exploded perspective view of the battery pack according to the present embodiment.
As shown in FIG. 1, the battery pack according to the present embodiment includes a flat rectangular lithium ion battery 1 and a resin holder 2 disposed therearound from an upper case 4 and a lower case 5. It has a structure housed in an exterior case.
[0011]
The lithium ion battery 1 includes a negative electrode terminal 12 protruding from one of the main surfaces. The outer can 11 serves as a positive electrode except for a portion where the negative electrode terminal 12 protrudes.
The upper case 4 is provided with openings 41 and 42 for exposing the external input / output terminals 21 and 22 to the outside.
[0012]
A pair of comb-shaped electrodes 61 and 62 are formed on the inner surface of the lower case 5. The electrodes 61 and 62 are arranged such that the protruding portion of one electrode is located at the concave portion of the other electrode, and a gap therebetween is distributed over the entire inner surface of the lower case 5. Specifically, the electrodes 61 and 62 are formed in a thin film shape by applying a conductive paint on the inner surface of the lower case 5. The electrodes 61 and 62 form the immersion sensor 6.
[0013]
Insulating paper 32 is also interposed between the lithium ion battery 1 and the lower case 5. This is to prevent the electrodes 61 and 62 from electrically contacting the outer can 11.
The holder 2 is provided with external input / output terminals 21 and 22 and connection terminals 23 and 24, a control circuit 25 mounted on a printed circuit board (not shown), a switching element 26, a protection circuit 27, and the like.
[0014]
An insulating paper 31 is interposed between the holder 2 and the surface of the lithium ion battery 1 on which the negative electrode terminal 12 protrudes. This is to prevent electrical contact between the wiring formed on the holder 2 and the outer can 11, and a window is formed at a portion corresponding to the negative electrode terminal 12.
Circuits and elements mounted on the holder 2 will be described with reference to FIG. In FIG. 2, the holder 2 is indicated by a broken line so that the connection relation between each circuit and element can be easily understood. Although not shown, the control circuit 25, the switching element 26, and the protection circuit 27 are mounted on a printed circuit board and mounted on the holder 2.
[0015]
In FIG. 2, when the holder 2 is combined with the lithium ion battery 1, the negative electrode terminal 12 is connected to the connection terminal 23.
The connection terminal 23 is connected to the switching element 26 by a wiring 231. As the switching element 26, for example, an n-channel MOS FET can be used. The switching element 26 is connected to the control circuit 25 by a wiring 261, and is connected to the protection circuit 27 by a wiring 271.
[0016]
The protection circuit 27 prevents overcharge and overdischarge during charging and discharging using a built-in thermistor, and is connected to the external input / output terminal 22 on the negative electrode side via a wiring 221.
On the other hand, the connection terminal 24 is connected to the main surface of the bottom portion of the outer can 11 of the lithium ion battery 1.
[0017]
The connection terminal 24 is connected to the external input / output terminal 21 on the positive electrode side by a wiring 241, and is connected to the control circuit 25 and the protection circuit 27 by wirings 242 and 243. The wirings 242 and 243 are for supplying circuit driving power to the control circuit 25 and the protection circuit 27.
In FIG. 2, each wiring formed on the holder 2 is drawn away from the holder 2 for the sake of convenience. However, in actuality, the printed wiring formed along the holder 2 except for the wirings 251 and 252. Wiring.
[0018]
The operation performed by the battery pack having the above structure when water enters the inside will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the above-described battery pack.
In the above-described battery pack, when moisture enters, the gap between the electrode 61 and the electrode 62 is distributed over the entire inner surface of the lower case 5, so that even if the amount of the entered moisture is small, There is a high possibility that moisture will adhere to any part of the gap between the electrode 61 and the electrode 62. In that case, the electrode 61 and the electrode 62 are in a conductive state. When the electrodes 61 and 62 are brought into the conductive state, the control circuit 25 detects the electric resistance between them, and detects that moisture has entered. That is, the control circuit 25 uses the fact that the electric resistance value between the electrode 61 and the electrode 62 becomes extremely small as compared with the case where water does not adhere to the gap due to the water adhering to the gap. Do.
[0019]
Note that the control circuit 25 may measure the electric conductivity instead of measuring the electric resistance between the electrode 61 and the electrode 62 to detect the inundation.
The control circuit 25 immediately outputs a connection cutoff signal to the switching element 26 when the electric resistance between the electrode 61 and the electrode 62 is significantly reduced as compared with the normal state as described above.
[0020]
The switching element 26 normally connects the connection terminal 23 and the protection circuit 27 in a normal state. However, when the connection cutoff signal from the control circuit 25 is received, the connection between the connection terminal 23 and the protection circuit 27 is established. Cut off.
The battery pack that has been flooded inside automatically shuts off the supply of electric power to the outside by interrupting the electrical connection between the connection terminal 23 and the protection circuit 27 as described above.
[0021]
Therefore, in this battery pack, even if moisture enters the inside of the battery pack, before the protection circuit 27 is broken or the battery is corroded, the water entry sensor 6 quickly detects the water entry and the control circuit 25 detects the water entry. A connection disconnection signal is output to the switching element 26 based on the result, and the switching element 26 receiving the signal disconnects the connection between the lithium-ion battery 1 and the external input / output terminals 21 and 22. It is possible to avoid danger such as liquid leakage in the lithium ion battery 1.
[0022]
If the battery pack has been disconnected due to water intrusion as described above, the user should ask the manufacturer or the lighting to inspect the battery pack, and if it can be reused after the internal moisture has dried, do not discard it and reuse it. You can do it.
In the present embodiment, a battery pack containing one lithium-ion battery has been described as an example, but the present invention is not limited to the type and number of batteries.
[0023]
Further, in the present embodiment, the electrodes 61 and 62 are arranged on the inner surface of the lower case 5, but the place where the electrodes are formed is not limited to this. The location where the electrodes are formed may be any location where infiltration can be detected early inside the battery pack. For example, the location around the openings 41 and 42 on the inner surface of the upper case 4 and the surface of the holder 2 There may be. For the arrangement of the electrodes 61 and 62 on the surface of the holder 2, a space for disposing the electrodes 61 and 62 on the surface of the holder 2 may be provided. It is also preferable to adopt a method of laminating on each circuit, wiring, or the like via the above.
[0024]
【The invention's effect】
The battery pack according to the present invention includes a flood detection sensor that detects moisture that has entered the interior of the exterior body, a control circuit that outputs a connection break signal based on the flood detection result of the flood sensor, and a connection break signal from the control circuit. And a connection interrupting element for interrupting an electrical connection between the battery and a terminal for inputting and outputting power.
[0025]
In this battery pack, even if water has entered the inside of the pack, the flood detection sensor detects the flooding, and based on the result of the flood detection, the control circuit outputs a connection disconnection signal to the connection disconnection element. The connection disconnecting element that has received the signal can interrupt the electrical connection between the battery and the external input / output terminal.
Therefore, in the battery pack of the present invention, even if moisture enters the inside of the battery pack, before the protection circuit is broken or the battery is corroded, the flood detection sensor quickly detects the flood, and the control circuit detects the detection result. The connection disconnection signal is output to the connection disconnection element based on the condition, and the connection disconnection element that receives the signal disconnects the connection between the battery and the external input / output terminal. Can be avoided.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a battery pack according to an embodiment of the present invention.
FIG. 2 is a detailed diagram showing a connection relationship of a circuit, an element, and the like mounted on a holder.
FIG. 3 is a block diagram showing an electrical configuration of the battery pack according to the embodiment of the present invention.
[Explanation of symbols]
1. 1. Lithium ion battery Holder4. Upper case 5. Lower case 6. Inundation detection sensor 25. Control circuit 26. Switching element 27. The protection circuits 61, 62. Inundation sensing electrode

Claims (3)

In a battery pack in which a battery is housed in an outer case and has an external input / output terminal connected to an external circuit in the outer case, a flood sensor for detecting moisture entering the interior of the outer case, and flooding of the flood sensor A control circuit that outputs a connection cutoff signal based on the sensing result, and a connection cutoff element that receives a connection cutoff signal from the control circuit and cuts off an electrical connection between the battery and the external input / output terminal. Wherein the water immersion detection sensor is formed by applying a conductive paint on an inner surface of the outer case . The flooded sensitive sensor is a pair of electrodes formed to maintain a gap each other physician, the pair of electrodes, so distributed over the entire area of at least one surface of the inner surface of the outer casing The battery pack according to claim 1, wherein the battery pack is disposed in a battery pack. 3. The battery pack according to claim 2, wherein each of the pair of electrodes has a comb shape, and a convex portion of one electrode is located at a concave portion of the other electrode. 4.

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