JP2007043800A - Protector of battery and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe protector of a battery for entirely blocking an electrical connection with respect to the battery at abnormality times. <P>SOLUTION: The protector has a thermosensitive element 2, operated in response to a temperature and switching a conduction state between a first terminal 12a and a second terminal 12b provided in a body, and a resistive element 5 for carrying a current and heating the thermosensitive element 2, when the thermosensitive element 2 operates. The body is provided with a third terminal 13a for carrying a current to the resistive element 5. The thermosensitive element 2 switches a fixed contact 11 for carrying a current to the second terminal 12b, accompanying its operation and a working contact 13 for carrying a current to the third terminal 13a via the resistive element 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery protection device and a battery pack for switching a contact at a predetermined set temperature by operation of a thermal element to protect the battery, and more particularly, provided with a heating resistor for preventing reoperation after the thermal element is operated. The present invention relates to a battery protection device and a battery pack.

  Conventionally, a thermally responsive switch using a bimetal is known, and it is also known to use this as a battery protection device. The thermal responsive switch is configured to switch the contact point by operating the movable contact by reversing the bimetal when the temperature exceeds a predetermined set temperature. After the temperature rises and the contacts are switched, if the temperature drops, the bimetal will reverse again, and the contacts will return to their original state. Requires mechanism.

In the conventional thermal responsive switch, as shown in Patent Document 1, when the heating resistance is brought into contact with the bimetal and the movable contact is operated by reversing the bimetal, the heating resistance is energized, which heats the bimetal and its inverted state What is known to maintain
JP 7-153499 A

  Conventional battery protection devices are connected in the battery pack as follows. FIG. 11 shows a configuration diagram of a conventional battery pack. As shown in this figure, the battery pack includes a battery 100, a protection device 101, a first output terminal 102 connected to the positive electrode 100a of the battery 100, a negative electrode 100b of the battery 100, and the protection device 101. And a second output terminal 103 connected to each other.

  The protective device 101 includes a bimetal 110 that operates according to temperature, and a resistor 111 that is provided in parallel with the bimetal 110, and the bimetal 110 is electrically connected to the first terminal 112 and the second terminal 113 by the operation. Is switched. In the state of FIG. 11, current flows from the second terminal 113 to the first terminal 112 via the bimetal 110.

  When the temperature rises, the bimetal 110 reverses and switches the conduction state. In FIG. 12, the block diagram of the battery pack after the operation of the bimetal 110 is shown. As shown in this figure, when the bimetal 110 is inverted, the conduction state between the first terminal 112 and the second terminal 113 via the bimetal 110 is released, and the first terminal 112 and the first terminal 112 via the resistor 111 are released. The second terminal 113 becomes conductive. Therefore, the current flows through the resistor 111 and the resistor 111 generates heat, and the bimetal 110 can be heated and the inverted state can be maintained.

  However, in the conventional battery protection device, since the resistor 111 is provided in parallel with the bimetal 110, even if the bimetal 110 releases the conduction between the first terminal 112 and the second terminal 113, it is electrically Connections are not completely blocked. Therefore, even when the bimetal 110 is in operation, there is a problem that current flows through the battery 100 and damages the battery 100.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly safe battery protection device and a battery pack using the same that can completely cut off an electrical connection to the battery in the event of an abnormality.

In order to solve the above-described problems, a battery protection device according to the present invention includes a thermal element that operates according to temperature and switches a conduction state between a first terminal and a second terminal provided in a main body, and the thermal element includes: In a battery protection device having a resistor that is energized when heated to heat the thermal element,
The main body is provided with a third terminal that conducts to the resistor, and the thermal element has a fixed contact that conducts with the second terminal in accordance with its operation, and the third terminal via the resistor. And switching the contact for operation to be conducted.

  In the battery protection device according to the present invention, the thermal element includes a first movable contact that contacts and separates from the fixed contact, and a second movable contact that contacts and separates the contact for operation. It is configured as a feature.

Furthermore, the battery protection device according to the present invention is a thermal element that operates according to temperature and switches the conduction state between the first terminal and the second terminal provided in the main body, and is energized when the thermal element operates. And a battery protection device having a resistor for heating the thermal element.
The main body is provided with a third terminal, the resistor is provided in a polymerized form on the surface of the thermal element, one end is electrically connected to the first terminal, and the other end is associated with the operation of the thermal element. It is configured to conduct to the contact for operation that conducts to the third terminal.

  Furthermore, the battery protection device according to the present invention is characterized in that the thermal element is made of bimetal.

The battery pack according to the present invention includes a battery, a first output terminal and a second output terminal that are electrically connected to both electrodes of the battery, and protection of the battery according to any one of claims 1 to 4. A battery pack comprising a device,
One electrode of the battery is connected to the second terminal of the battery protection device, the other electrode is connected to the first output terminal, and the first terminal of the battery protection device is the second terminal. The third terminal of the battery protection device is connected to the output terminal and is connected to the first output terminal.

  According to the battery protection device of the present invention, the main body is provided with the third terminal that conducts to the resistor, and the thermal element has a fixed contact that conducts with the second terminal in accordance with its operation, and the resistor. By switching the operating contact that is electrically connected to the third terminal via the third terminal, the electrical connection between the first terminal and the second terminal is completely interrupted during the operation of the thermal element, and then the third terminal is passed through the third terminal. Since the current flows and the resistor can generate heat, it is possible to provide a highly safe battery protection device that does not cause current to flow to the battery side and does not damage the battery when an abnormality occurs.

  Further, according to the battery protection apparatus of the present invention, the thermal element has the first movable contact that contacts and separates from the fixed contact and the second movable contact that contacts and separates the contact for operation. As a result, the electrical connection can be reliably made to each of the fixed contact and the contact for operation.

  Furthermore, according to the battery protection device of the present invention, the main body is provided with the third terminal, the resistor is provided in a polymerized form on the surface of the thermal element, and one end is electrically connected to the first terminal, The other end is electrically connected to the contact for operation that is electrically connected to the third terminal in accordance with the operation of the thermal element, so that the electrical connection between the first terminal and the second terminal is completely cut off during the operation of the thermal element. Since a current flows through the third terminal and the resistor can be heated, a highly safe battery protection device that does not flow to the battery side and does not damage the battery in the event of an abnormality. Can do.

  Furthermore, according to the battery protection device of the present invention, the thermal element is made of bimetal, so that the thermal element can be formed at low cost.

  According to the battery pack of the present invention, one electrode of the battery is connected to the second terminal of the battery protection device, and the other electrode is connected to the first output terminal. The terminal of 1 is connected to the second output terminal, and the third terminal of the battery protection device is connected to the first output terminal, so that the battery is surely cut off by the protection device. In addition, the external power from the charger can be supplied to the resistor, and a highly safe battery pack can be obtained.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an exploded perspective view of a battery protection device according to this embodiment. As shown in this figure, the battery protection device according to the present embodiment is such that a bimetal 2 and a resistor 5 are placed in a case-like main body 1 and covered with a cover body 6 from above. The insulating coat 3 and the electrode 4 associated therewith are both formed into a thin film shape and have flexibility, and are adhered to the surface of the bimetal 2.

  The main body portion 1 has a storage portion 10 in which the bimetal 2, the resistor 5, and the like are stored. A fixed contact 11 is provided at one end of the bottom surface of the storage portion 10, and the fixed contact 11 is directed outward from the side surface of the main body portion 1. And the second terminal 12b protruding. In addition, a connection surface 14 connected to one end of the bimetal 2 is provided at the other end of the bottom surface of the storage unit 10, which is a first terminal that protrudes on the opposite side to the second terminal 12 b. 12a is conducted.

  The bimetal 2 has an inversion part 20 formed in a dome shape at the center, and when the temperature changes, the inversion part 20 is inverted so that the bimetal 2 is warped to the opposite side. To do. In addition, a movable contact 21 is formed on the lower surface of the distal end portion of the bimetal 2 and is in contact with and away from the fixed contact 11.

  The insulating coat 3 is for insulating the bimetal 2 and the electrode 4 and has flexibility. Further, the electrode 4 is also a sheet having flexibility, and is provided in a region excluding the reversing portion 20 of the bimetal 2 and is formed in a comb shape on both sides of the reversing portion 20. The resistor 5 is disposed in the comb-like portion, and when a voltage is applied to the electrode 4, a current flows through the resistor 5. One end of the electrode 4 is electrically connected to the connection surface 14 via the bimetal 2, and the other end is brought into contact with the operating contact 13 provided in the cover body 6 when the bimetal 2 is reversed.

  The resistor 5 is a PTC resistor having elasticity, and is formed by blending particles in which a resin and carbon are mixed in an elastomer. This resistor 5 is provided in the area | region except the inversion part 20 of the bimetal 2, and its peripheral part 21, and is arrange | positioned 1 each on both sides on both sides of the inversion part 20. FIG.

  The cover body 6 is formed so as to cover the upper surface of the main body 1, and an operation contact 13 is provided at an end of the upper surface. During operation, the contact 13 is electrically connected to the third terminal 13 a protruding from the side surface of the cover body 6. Further, when the bimetal 2 is inverted, the contact 13 at the time of operation becomes in a state where one end of the electrode 4 provided on the bimetal 2 comes into contact and is conductive.

  The insulating coat 3, the electrode 4, and the resistor 5 provided on the surface of the bimetal 2 may be integrated with the bimetal 2 by sticking, or may be integrated by printing on the surface of the bimetal 2. You may do it. Further, since the insulating coat 3, the electrode 4, and the resistor 5 are provided so as to avoid the region of the inversion portion 20 of the bimetal 2, the inversion operation of the bimetal 2 is not hindered.

  FIG. 2 shows a cross-sectional view of the battery protection device before operation. As shown in this figure, in the battery protection device before operation, the inversion portion 20 of the bimetal 2 is in a curved state so as to swell upward, and the movable contact 21 provided at the tip of the bimetal 2 is It is in the state which contacted the fixed contact 11 of the main-body part 1 bottom face. Therefore, the first terminal 12 a and the second terminal 12 b are in a conductive state via the bimetal 2 and the movable contact 21.

  FIG. 3 shows a cross-sectional view of the battery protection device after the operation. As shown in this figure, when the temperature exceeds a predetermined temperature, the reversing portion 20 of the bimetal 2 is reversed so as to bulge downward, and the movable contact 21 provided at the front end of the bimetal 2 It will be in the state away from. On the other hand, the end portion of the electrode 4 provided on the upper surface side of the bimetal 2 comes into contact with the contact point 13 during operation provided on the upper surface of the cover body 6 and is brought into conduction with the third terminal 13a. That is, when the bimetal 2 is operated, the conduction between the first terminal 12a and the second terminal 12b is released, and the first terminal 12a and the third terminal 13a are brought into conduction through the resistor 5. Switch.

  Next, a battery pack using this battery protection device will be described. In FIG. 4, the block diagram of the battery pack in the state before operation | movement of the bimetal 2 is shown. As shown in this figure, the battery pack is provided with a battery 30, a protection device 31 described above, a first output terminal 32, and a second output terminal 33.

  The protective device 31 includes a bimetal 2 and a resistor 5 inside the main body 1 and includes a first terminal 12a, a second terminal 12b, and a third terminal 13a. The first terminal 12a is connected to the second output terminal 33 of the battery pack, the second terminal 12b is connected to the negative electrode 30b of the battery 30, and the third terminal 13a is connected to the positive electrode 30a of the battery 30. Each is connected to the first output terminal 32.

  In a state before the operation, the bimetal 2 is in contact with the fixed contact 11 that conducts with the second terminal 12b, and conducts between the first terminal 12a and the second terminal 12b. Further, one end of the resistor 5 provided in a superposed form on the surface of the bimetal 2 is not in contact with anywhere, and therefore no current flows through the resistor 5. In the normal state shown in FIG. 4, the current flows from the first output terminal 32 of the battery pack toward the second output terminal 33 via the battery 30, and the battery 30 is charged.

  In FIG. 5, the block diagram of the battery pack in the state after the operation of the bimetal 2 is shown. When the abnormality occurs and the temperature rises and the bimetal 2 is reversed, the bimetal 2 is separated from the fixed contact 11, and the conduction state between the first terminal 12a and the second terminal 12b is released. On the other hand, one end of the resistor 5 comes into contact with the contact 13 during operation, and the first terminal 12a and the third terminal 13a are brought into conduction through the resistor 5. As a result, current flows from the third terminal 13a to the first terminal 12a via the resistor 5.

  Since the third terminal 13a is connected to the first output terminal 32 of the battery pack, the current flows directly from the first output terminal 32 to the third terminal 13a, heating the bimetal 2 and maintaining the inverted state. can do. That is, since the electrical connection between the first terminal 12a and the second terminal 12b is interrupted, no current flows on the battery 30 side. Therefore, the battery 30 is not damaged when the bimetal 2 is reversed when an abnormality occurs.

  Next, a second embodiment of the present invention will be described. FIG. 6 shows an exploded perspective view of the battery protection device in the present embodiment. As shown in this figure, the battery protection device of this embodiment is similar to that of the first embodiment, in which a bimetal 2 and a resistor 5 are housed in a case-like main body 1 and a cover body 6 is used from above. It is a cover.

  In addition, the main body 1 is provided with a fixed contact 11 and a second terminal 12 b that conducts to the fixed contact 11, and a first terminal 12 a that conducts to one end of the bimetal 2 via the connection surface 14. On the other hand, in this embodiment, the resistor 5 is attached not to the surface of the bimetal 2 but to the upper surface of the cover body 6. Further, a third terminal 13 a that is electrically connected to the resistor 5 is provided on the upper surface of the cover body 6.

  FIG. 7 shows a cross-sectional view of the battery protection device before operation. As shown in this figure, in the battery protection device before operation, the reversing portion 20 of the bimetal 2 is curved so as to swell upward, and the tip of the bimetal 2 has a first movable portion on the lower surface side. A contact 21 is provided and is in contact with the fixed contact 11 on the bottom surface of the main body 1. Therefore, the first terminal 12 a and the second terminal 12 b are in a conductive state via the bimetal 2 and the movable contact 21.

  Further, a second movable contact 22 is formed on the upper surface side of the tip end portion of the bimetal 2 and faces the resistor 5 provided on the upper surface of the cover body 6. The resistor 5 is a PTC heater and has a certain thickness. Therefore, the cover body 6 in this embodiment is formed thicker than that in the first embodiment. An operating contact point 13 for conducting with the second movable contact 22 is formed at a portion of the resistor 5 facing the second movable contact 22.

  FIG. 8 shows a cross-sectional view of the battery protection device in a state after operation. As shown in this figure, when the temperature exceeds a predetermined temperature, the reversing portion 20 of the bimetal 2 is in a curved state so as to reverse and swell downward, and the first movable contact 21 provided at the tip of the bimetal 2 is The state is separated from the fixed contact 11. On the other hand, the second movable contact 22 provided on the upper surface side of the bimetal 2 comes into contact with the contact 13 during operation of the resistor 5 and is in conduction with the third terminal 13 a via the resistor 5. That is, when the bimetal 2 is operated, the conduction between the first terminal 12 a and the second terminal 12 b is released, and the first terminal 12 a and the third terminal 13 a are brought into conduction through the resistor 5. Switch.

  Next, a battery pack using this battery protection device will be described. In FIG. 9, the block diagram of the battery pack in the state before operation | movement of the bimetal 2 is shown. As shown in this figure, the battery 30 and the protection device 31 and the connection between the first output terminal 32 and the second output terminal 33 are made in the same manner as in the first embodiment. The terminal 12 a is connected to the second output terminal 33, the second terminal 12 b is connected to the negative electrode 30 b of the battery 30, and the third terminal 13 a is connected to the first output terminal 32. In the normal state of FIG. 9, current flows from the first output terminal 32 toward the second output terminal 33 via the battery 30, and the battery 30 is charged.

  In FIG. 10, the block diagram of the battery pack in the state after operation | movement of the bimetal 2 is shown. As shown in this figure, when the temperature rises and the bimetal 2 reverses, the bimetal 2 moves away from the fixed contact 11 that is in conduction with the second terminal 12 b, contacts the contact 13 during operation, and the second via the resistor 5. 3 to the terminal 13a. In this state, a current flows from the first output terminal 32 to the third terminal 13 a side, and further flows to the second output terminal 33 through the resistor 5 and the bimetal 2. As a result, the resistor 5 generates heat, and the inverted state can be maintained by heating the bimetal 2.

  As described above, by providing the resistor 5 separately from the bimetal 2 in the main body including the main body 1 and the cover body 6, the third terminal 13 a is connected to the first of the battery pack as in the first embodiment. By connecting to the output terminal 32, current can be prevented from flowing to the battery 30 side when the bimetal 2 is reversed, and the battery 30 can be prevented from being damaged.

  As a typical abnormal state in the battery pack, there is an overcharged state. This is a state that occurs when the voltage of the external power source connected for charging the battery pack is higher than a predetermined value. When the battery is a lithium ion battery, the specified charging voltage is about 4.2V, but when the voltage of the external power supply is 5V or more, there is a risk of overcharging. Considering the case where charging is performed with an automobile battery, a voltage close to 30 V may be applied at the maximum. For this reason, the protection function needs to operate at a voltage in the range of 5V to 30V for overcharge protection.

  When the bimetal 2 is inverted and the inverted state of the bimetal 2 is maintained by heat generated by the current flowing through the resistor 5, the voltage applied to the resistor is conventionally the voltage difference between the external power supply and the battery. In the case of a lithium ion battery, since the rated voltage is about 3.7 V, the voltage applied to the resistor is in the range of 1.3 V to 26.3 V, and the heat generation amount in the voltage range of about 20 times is an appropriate range. A body is needed.

  On the other hand, in the present embodiment, since no current flows through the battery 30, the voltage of the battery 30 is not applied to the resistor 5. Therefore, the voltage range applied to the resistor 5 is the fluctuation range of the external power supply itself. In other words, any heat generation amount that is appropriate in a voltage range of 6 to 5V to 30V may be used.

  Since the amount of heat generated by the resistor 5 is proportional to the square of the voltage when the resistance value is constant, conventionally, the difference in the amount of heat generated in the voltage range applied to the resistor is up to 400 times. It was necessary to use one having a steep temperature and resistance value change characteristic. On the other hand, according to the present embodiment, the difference in the amount of heat generated in the voltage range applied to the resistor 5 is 36 times, so that a simple resistor or an inexpensive PTC element can be used, and the cost can be reduced. .

  Embodiments to which the present invention has been applied have been described so far, but the application of the present invention is not limited to these embodiments, and can be variously applied within the scope of the technical idea.

It is a disassembled perspective view of the protection apparatus of the battery in 1st Embodiment. It is a longitudinal cross-sectional view in the state before operation | movement of the protection apparatus of a battery. It is a longitudinal cross-sectional view in the state after operation | movement of the protection apparatus of a battery. It is a block diagram in the state before operation | movement of a battery pack. It is a block diagram in the state after operation | movement of a battery pack. It is a disassembled perspective view of the protection apparatus of the battery in 2nd Embodiment. It is a longitudinal cross-sectional view in the state before operation | movement of the protection apparatus of a battery. It is a longitudinal cross-sectional view in the state after operation | movement of the protection apparatus of a battery. It is a block diagram in the state before operation | movement of a battery pack. It is a block diagram in the state after operation | movement of a battery pack. It is a block diagram in the state before operation | movement of the conventional battery pack. It is a block diagram in the state after operation | movement of the conventional battery pack.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main-body part 2 Bimetal 3 Insulation coat 4 Electrode 5 Resistor 6 Cover body 10 Storage part 11 Fixed contact 12a 1st terminal 12b 2nd terminal 13 Operation | movement contact 13a 3rd terminal 14 Connection surface 20 Inversion part 21 1st Movable contact 22 second movable contact 30 battery 31 protection device 32 first output terminal 33 second output terminal

Claims (5)

A thermal element that operates according to temperature and switches between a first terminal and a second terminal provided in the main body, and a resistor that is energized to heat the thermal element when the thermal element operates. In the battery protection device we have,
The main body is provided with a third terminal that conducts to the resistor, and the thermal element has a fixed contact that conducts with the second terminal in accordance with its operation, and the third terminal via the resistor. A battery protection device for switching between a contact for operation and electrical connection.   2. The battery according to claim 1, wherein the thermosensitive element has a first movable contact contacting and separating from the fixed contact, and a second movable contact contacting and separating from the operation contact. Protective device. A thermal element that operates according to temperature and switches between a first terminal and a second terminal provided in the main body, and a resistor that is energized to heat the thermal element when the thermal element operates. In the battery protection device we have,
The main body is provided with a third terminal, the resistor is provided in a polymerized form on the surface of the thermal element, one end is electrically connected to the first terminal, and the other end is associated with the operation of the thermal element. A battery protection device, wherein the battery protection device is electrically connected to an operating contact point that is electrically connected to the third terminal.   The battery protection device according to claim 1, wherein the thermal element is made of a bimetal. A battery pack comprising: a battery; a first output terminal and a second output terminal that are electrically connected to both electrodes of the battery; and the battery protection device according to claim 1. ,
One electrode of the battery is connected to the second terminal of the battery protection device, the other electrode is connected to the first output terminal, and the first terminal of the battery protection device is the second terminal. A battery pack connected to an output terminal, wherein the third terminal of the battery protection device is connected to the first output terminal.

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