JP2003059467A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack causing no short circuit in a circuit and wiring between an internal battery and input-output terminals even when water infiltration is caused in the battery pack. SOLUTION: Electrodes 61 and 62 are arranged on a surface inside of a lower side case 5. When water infiltrates inside the battery pack and the water sticks to clearance between the electrode 61 and the electrode 62, both electrodes 61 and 62 are put in an electrically continuous state. A control circuit 25 connected with these electrodes 61 and 62 detects that both electrodes 61 and 62 become the electrically continuous state, and outputs a connection cutoff signal to a switching element 26. The switching element 26 receiving this signal cuts off the electric connection between the battery 1 and the external input-output terminals 21 and 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack used as a power source for electronic devices and the like.

[0002]

2. Description of the Related Art In recent years, a battery pack in which one or a plurality of batteries are housed in an outer case made of resin is used in electronic equipment. Inside the battery pack, in addition to the battery, there is a protective circuit to prevent overcharging and overdischarging during charging / discharging, and lead wiring to electrically connect the battery to the external input / output terminals or protective circuit. It is stored. The protection circuit is mounted on a printed circuit board, and a lead plate or lead wire is used for the lead wiring. These printed circuit boards and lead wirings may be arranged directly on the periphery of the battery, or may be fixed and arranged on a resin holder along the shape of the inside of the outer case of the battery pack.

[0003]

By the way, an electronic device such as a mobile phone is often used outdoors, and is exposed to rainwater when used in the rain, or is used as a drink on a table. May be soaked. In such a case, the battery pack used as a power source for electronic devices may get wet with water such as rainwater and drinks, and water may get in from the external input / output terminals exposed on the surface of the outer case. It may end up. Further, in a battery pack in which a crack occurs in the outer case of the battery pack due to dropping or the like, water may intrude also from the cracked portion.

When water enters the inside of the battery pack,
Water may adhere to the protection circuit or lead wiring to cause a short circuit, which may destroy the protection circuit. If the battery is left in a short-circuited state and continues to be over-discharged, deterioration of the battery significantly progresses, which may cause liquid leakage. Further, if water also adheres to the terminal portion of the battery, it may cause corrosion and further cause liquid leakage.

In order to avoid such a situation, Japanese Unexamined Patent Publication No. 11-144695 discloses a technique of making a user of a device recognize the intrusion of water by using a water immersion determination seal. However, in the technology disclosed above, it is possible for the user of the device to recognize the intrusion of water into the battery pack.
This is the time when the battery pack is taken out of the device and the submergence judgment sticker is checked, and a short circuit occurs in the protection circuit and wiring inside the battery pack from the occurrence of flooding until the user's recognition.

In order to solve the above problems, the present invention is a battery pack which does not cause a short circuit in the circuit and wiring between the battery and the external input / output terminal even if water is generated in the battery pack. The purpose is to provide.

[0007]

In order to achieve the above object, a battery pack of the present invention is based on a water infiltration sensor for detecting water invading the inside of an outer case and a water infiltration detection result of the water infiltration sensor. It is characterized by including a control circuit that outputs a connection cutoff signal and 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.

In this battery pack, when water enters the inside of the battery pack, the control circuit outputs a connection cutoff signal based on the result of water detection detected by the water detection sensor, and the connection cutoff element accepts the signal to disconnect the battery from the battery. Since the electrical connection with the external input / output terminal is cut off, even if the circuit and wiring between the battery and the external input / output terminal become conductive due to moisture, the connection cutoff element It is possible to prevent short circuit from occurring in the circuit and wiring between the external input / output terminal and the external input / output terminal.

The water immersion sensor is preferably a pair of electrodes formed on the inner surface of the outer case with a gap maintained therebetween. Further, it is preferable that the pair of electrodes be arranged so as to be distributed over the entire area of 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 that the convex portions of one electrode are located in the concave portions of the other electrode. This is because if the pair of electrodes is used as a water immersion sensor, when water adheres to the gap between the electrodes, the electrodes become conductive.
Inundation is detected. That is, in the region where the gap is provided, it is possible to accurately detect the intrusion of water which causes a short circuit in the internal wiring and circuit.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of a battery pack according to an embodiment of the present invention will be described with reference to FIG. Figure 1
FIG. 4 is a developed perspective view of the battery pack according to the present embodiment. Figure 1
As shown in FIG. 3, the battery pack according to the present embodiment includes a flat-shaped lithium-ion battery 1 and a resin holder 2 arranged around the flat-shaped lithium-ion battery 1, and an outer case including an upper case 4 and a lower case 5. It has a structure housed in a case.

The lithium ion battery 1 has one of the main surfaces.
The surface is provided with the protruding negative electrode terminal 12. Exterior can 11
Is a positive electrode except for the portion where the negative electrode terminal 12 is provided in a protruding manner. The upper case 4 has external input / output terminals 21, 2
Openings 41 and 42 are provided to expose 2 to the outside.

A pair of comb-shaped electrodes 61 and 62 are formed on the inner surface of the lower case 5. Electrodes 61, 62
Are arranged such that the convex portion of one electrode is located in the concave portion of the other electrode, and the mutual gaps are distributed over the entire inner surface of the lower case 5. Specifically, the electrodes 61 and 62 are
It is a thin film formed by applying a conductive paint on the inner surface of the lower case 5. This electrode 61, 62
Form the water immersion sensor 6.

An insulating paper 32 is also inserted between the lithium ion battery 1 and the lower case 5. This is electrode 6
1, 62 and the outer can 11 are prevented from electrically contacting each other. The holder 2 has an external input / output terminal 21,
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.

Insulating paper 31 is inserted between the holder 2 and the surface of the lithium-ion battery 1 on which the negative electrode terminal 12 is provided. This is to prevent the wiring formed on the holder 2 and the outer can 11 from electrically contacting each other, and a window is formed in 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, in order to make it easy to understand the connection relationship between each circuit and element,
The holder 2 is shown by a broken line. Further, although not shown in the drawing, the control circuit 25, the switching element 26, and the protection circuit 27 are mounted on the printed board and mounted on the holder 2.

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 the wiring 231. The switching element 26 includes, for example, an n-channel MOS type FET.
Etc. can be used. The switching element 26 is
The wiring 261 is connected to the control circuit 25, and the wiring 271
Is connected to the protection circuit 27 by.

The protection circuit 27 prevents overcharging and overdischarging at the time of charging / discharging by using a built-in thermistor, and is connected to the external input / output terminal 22 on the negative electrode side by 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.

The connection terminal 24 is connected to the external input / output terminal 21 on the positive electrode side by a wiring 241, and the wiring 242, 243.
Are connected to the control circuit 25 and the protection circuit 27 by. The wirings 242 and 243 are for supplying electric power for circuit driving to the control circuit 25 and the protection circuit 27. Each wiring formed on the holder 2 is shown in FIG.
For convenience, each wire is drawn away from the holder 2,
Actually, the printed wiring is formed along the holder 2 except for the wirings 251 and 252.

The operation of 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 battery pack described above. In the above battery pack, when water penetrates inside, the gap between the electrode 61 and the electrode 62 is distributed over the entire inner surface of the lower case 5, so even if the amount of water that has entered is small, There is a high possibility that water 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 reach the conductive state, the control circuit 25
Detects the infiltration of water by detecting the electric resistance between them. 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, as compared with the case where water does not adhere. To do.

The control circuit 25 may measure the electric conductivity instead of measuring the electric resistance value between the electrodes 61 and 62 in order to detect the water immersion. Control circuit 25
When the electric resistance value between the electrode 61 and the electrode 62 is greatly reduced as compared with the normal state as described above, immediately outputs the connection cutoff signal to the switching element 26.

In the normal state, the switching element 26 connects the connection terminal 23 and the protection circuit 27, but when a connection cutoff signal from the control circuit 25 is received,
The connection between the connection terminal 23 and the protection circuit 27 is cut off.
The battery pack that has been flooded inside automatically cuts off the supply of electric power to the outside by cutting off the electrical connection between the connection terminal 23 and the protection circuit 27 as described above.

Therefore, in this battery pack, even if water enters the inside of the battery pack, before the damage of the protection circuit 27 or the corrosion of the battery is caused, the water detection sensor 6 quickly detects the water, and the control circuit 25 outputs a connection cutoff signal to the switching element 26 based on the detection result, and the switching element 26 receiving this cuts off the connection between the lithium ion battery 1 and the external input / output terminals 21 and 22. It is possible to avoid the risk of liquid leakage in the stored lithium-ion battery 1.

If the user asks the manufacturer or the lighting to inspect the battery pack for which the connection has been cut off due to water infiltration as described above, and the water inside the battery pack can be reused after reuse, do not discard it. , Can be reused. In the present embodiment, a battery pack accommodating one lithium-ion battery has been described as an example, but the present invention is not limited to the type and number of batteries.

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 place where the electrode is formed may be a place where the water can be detected early in the battery pack, for example, around the openings 41 and 42 on the inner surface of the upper case 4 or on the surface of the holder 2. It may be. When disposing the electrodes 61, 62 on the surface of the holder 2, a place for disposing the electrodes 61, 62 on the surface of the holder 2 may be allocated, but in view of downsizing the battery pack, an insulating layer is used. It is also preferable to adopt a method of stacking on each circuit or wiring via the.

[0024]

The battery pack of the present invention comprises a water infiltration sensor for detecting water that has penetrated into the exterior body, a control circuit for outputting a connection cutoff signal based on the water infiltration detection result of the water infiltration sensor, and a control circuit. And a connection cut-off element that cuts off an electrical connection between the battery and a terminal for inputting and outputting electric power.

In this battery pack, even if water enters the inside of the pack, the water is detected by the water detection sensor, and the control circuit outputs a connection cutoff signal to the connection cutoff element based on the result of the water detection. However, the connection cutoff element receiving this can cut off the electrical connection between the battery and the external input / output terminal. Therefore, in the battery pack of the present invention,
Even if water enters the inside of the battery pack, the water detection sensor quickly detects the water before the protection circuit is destroyed or the battery is corroded, and the control circuit disconnects the connection based on the detection result. A signal is output, and the connection cutoff element that receives the signal cuts off the connection between the battery and the external input / output terminal. Therefore, it is possible to avoid the risk of liquid leakage in the battery housed inside.

[Brief description of 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 view showing a connection relationship between a circuit and elements 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. Lithium ion battery 2. holder 4. Upper case 5. Lower case 6. Infiltration sensor 25. Control circuit 26. Switching element 27. Protection circuit 61, 62. Infiltration sensing electrode

Claims (4)

[Claims] 1. A battery pack in which a battery is housed in an outer case and which has external input / output terminals connected to an external circuit in the outer case, wherein a water infiltration sensor for detecting water entering the outer case, A control circuit that outputs a connection cutoff signal based on the water detection result of the water detection sensor, and a connection cutoff signal from the control circuit is received to cut off the electrical connection between the battery and the external input / output terminal. A battery pack comprising: 2. The battery pack according to claim 1, wherein the water immersion sensor is a pair of electrodes formed on the inner surface of the outer case while maintaining a gap therebetween. 3. The pair of electrodes is arranged so as to be distributed over the entire area of at least one of the inner surfaces of the outer case.
The battery pack described in. 4. The pair of electrodes each have a comb shape, and are arranged such that a convex portion of one electrode is located in a concave portion of the other electrode. The battery pack according to any one of 1.