JP6708388B2 - Wetting sensor, switch element, battery system - Google Patents

Description

The present invention relates to a liquid wetting sensor that detects liquid intrusion, a switch element that opens an electric circuit according to liquid infiltration, and a battery system incorporating the same.

In recent years, lithium ion secondary batteries have been adopted in many mobile phones, notebook PCs, and the like. Since the lithium ion secondary battery has a high energy density, in order to ensure the safety of users and electronic devices, generally, several protection circuits such as overcharge protection and overdischarge protection are built in the battery pack and In this case, it has a function of shutting off the input/output of the battery pack. However, if the positive electrode/negative electrode insulating fitting portion of the battery corrodes due to water wetting, there is a risk that the pressure inside the battery leaks, the safety valve does not function properly, and a fire accident occurs.

JP, 11-144695, A JP, 2000-162081, A

There is a device that issues a warning by attaching a seal that detects a wet trace against water wetting (for example, see Patent Document 1), but since it does not limit the use of the battery, migration of the circuit board due to water wetting (Insulation deterioration) or short circuit may cause circuit malfunction. Further, there is a possibility that the same trouble as described above may occur even when the electrolyte leaks due to the abnormality of the battery.

In addition, as a measure against water wetting of electronic devices, there is also used a sensor which detects a liquid such as water and operates a protection circuit by a signal transmitted from the sensor which detects water wetting. For example, there has been proposed a water leak sensor including a detection unit composed of a pair of electrodes arranged facing each other at a predetermined interval on an insulating substrate (see, for example, Patent Document 2).

In this water leak sensor, when the electrodes of the detection unit are wet, a signal is input to the control circuit by leaking between the terminals, and the operation of the device is controlled. That is, this water-wetting sensor is operated under the condition that the liquid flows into the detection unit. Therefore, when the water-wet condition occurs, it is desirable that the liquid is positively flowed into the detection unit. It is also necessary to ensure the reliability of the sensor so that it will not malfunction unless it is wet with water so that the circuit does not need to be activated.

In a battery system such as a lithium-ion secondary battery, a method is proposed in which a fuse element is connected on the charge/discharge circuit of the battery cell and the fuse is blown by the heat of the heating resistor to interrupt the charge/discharge circuit. Has been done. For example, in the protection circuit 100 shown in FIG. 30, the FET 102 that switches the energization to the heating resistor 101, the battery stack 103 in which the battery cells are connected in series and/or in parallel, and the overcharging and overdischarging of the battery stack 103 are prevented. A control IC 104 is provided for monitoring and outputting a control signal to the FET 102 when the battery stack 103 is abnormal, and a fuse 105 connected on the charge/discharge path of the battery stack 103.

In the protection circuit 100, when there is no abnormality in the battery stack 103, energization of the heating resistor 101 is restricted by the FET 102. When the control IC 104 detects an abnormality such as overcharge or overdischarge of the battery stack 103, the protection circuit 100 causes the FET 102 to energize the heating resistor 101. As a result, the protection circuit 100 blows the fuse 105 due to the heat generation of the heating resistor 101, and cuts off the charging/discharging path of the battery stack 103.

However, in the protection circuit 100, the FET 102 and the control IC 104 for controlling the FET 102 are required in order to control the energization of the heating resistor 101, which causes an increase in the number of parts and an assembly man-hour, and also prevents water wetting and a battery. If the control IC 104 fails due to liquid leakage of the fuse, the fuse 105 may not be blown.

The present invention has been proposed in view of such conventional circumstances, a liquid wetting sensor for detecting liquid leakage from a battery or liquid leakage, for abnormalities such as water leakage or liquid leakage from a battery, An object of the present invention is to provide a switch element capable of safely opening an electric circuit and a battery system incorporating the switch element.

In order to solve the above-mentioned problems, the liquid wetting sensor according to the present invention has a reaction part that generates heat by touching a liquid, and a temperature-sensitive part whose electric characteristics change as the temperature of the reaction part changes. is there.

Further, the switch element according to the present invention includes a fusible conductor connected to an external circuit, a heat generating resistor, a reaction part that generates heat by touching a liquid, and a heat generating resistor connected to the temperature of the reaction part. A temperature sensitive portion whose electric characteristics change in accordance with the change, and the fusible conductor is melted and blown by the heat generation of the heating resistor whose energization amount increases due to the change in the electric characteristics of the temperature sensitive portion .

Further, a battery system according to the present invention includes a battery cell, a fusible conductor connected on a charge/discharge path of the battery cell, a heating resistor, a reaction part that generates heat by touching a liquid, and the heating resistor. is connected on the current path of the body, and a thermosensitive part electrical characteristics change with temperature change in the reaction portion, the heat generation of the heating resistor energization amount is increased by a change in electrical characteristics of said temperature sensitive portion To melt the fusible conductor.

Further, the battery system according to the present invention includes a battery cell, a fusible conductor connected on a charge/discharge path of the battery cell, a heating resistor, a reaction part that generates heat by touching a liquid, and the reaction part. A temperature-sensitive part whose electrical characteristics change with a temperature change, and a current control element for controlling energization of the heating resistor, the temperature-sensitive part and the current control element are connected , The current control element is energized due to a change in electrical characteristics , the energization of the heating resistor is started, and the fusible conductor is melted by the heat generated by the heating resistor.

Further, the switch element according to the present invention includes a fusible conductor connected to an external circuit and a reaction part that generates heat when touching a liquid, and the fusible conductor is melted and cut by the heat generated in the reaction part. ..

Further, the battery system according to the present invention includes a battery cell, a soluble conductor connected on the charge/discharge path of the battery cell, and a reaction part that generates heat when touched with a liquid. It melts the fusible conductor.

According to the present invention, when it becomes necessary to interrupt the current path of the external circuit, such as water wetting or liquid leakage from the battery, the electrical characteristics of the temperature-sensitive part change due to heat generation of the reaction part that comes into contact with the liquid, Power is supplied to the external circuit. As a result, the protection element can be activated, or the heating resistor can be energized and generate heat to melt the fuse element and interrupt the current path of the external circuit.

Further, according to the present invention, when it becomes necessary to interrupt the current path of the external circuit due to water wetting, liquid leakage from the battery, or the like, the fusible conductor is melted and blown by the heat generated in the reaction part that comes into contact with the liquid. It is possible to interrupt the current path of the external circuit that has been energized via the fusible conductor.

FIG. 1 is a diagram showing a schematic configuration of a liquid wetting sensor. FIG. 2 is an exploded perspective view showing a configuration example of the liquid wetting sensor. FIG. 3 is a diagram showing a circuit configuration of a battery pack using a liquid wetting sensor. 4A and 4B are views showing a protective element, FIG. 4A is a plan view, and FIG. 4B is a sectional view taken along line X-X′. 5A and 5B are circuit configuration diagrams of the protection element, where FIG. 5A shows the fuse element before melting and FIG. 5B shows the fuse element after melting. FIG. 6 is a diagram showing a circuit configuration of a battery pack using a liquid wetting sensor. FIG. 7 is an exploded perspective view showing a configuration example of the switch element. FIG. 8 is a sectional perspective view of the fuse element. 9A and 9B are diagrams showing a circuit configuration of the switch element, in which FIG. 9A shows a fuse element before being blown, and FIG. 9B shows a fuse element after being blown. FIG. 10 is a diagram showing a circuit configuration of a battery pack using a switch element. FIG. 11 is a diagram showing a circuit configuration of a battery pack using a switch element. 12A and 12B are diagrams showing a configuration example of a switch element in which a heating resistor is covered with a glass layer, FIG. 12A being a sectional view and FIG. 12B being a plan view. 13A and 13B are diagrams showing a configuration example of a switch element in which a power supply path to a heating resistor and a power supply path to a fuse element are separated, FIG. 13A being a sectional view and FIG. 13B being a plan view. FIG. 14 is a circuit diagram of a switch element in which a power supply path to the heating resistor and a power supply path to the fuse element are separated. FIG. 15 is a diagram showing a circuit configuration of a battery pack using a switch element in which a power supply path to the heating resistor and a power supply path to the fuse element are separated. 16A and 16B are perspective views showing a casing of the switch element. FIG. 16A is a state in which an inlet is formed on the top surface, FIG. 16B is a state in which a plurality of inlets are formed in the top surface, and FIG. () shows a state in which the inlets are formed on the top and side surfaces, and (D) shows a state in which a plurality of inlets are formed on the top and side surfaces. FIG. 17 is a perspective view showing a switch element using a cylindrical cover member. FIG. 18 is a perspective view showing a switch element using a casing having a discharge port. FIG. 19 is a cross-sectional view showing a switch element having a discharge port provided at the same height as the position where the reaction part is provided. FIG. 20 is a perspective view showing a switch element using a housing in which a slit-shaped inlet and a slit-shaped outlet are formed. 21A and 21B are diagrams showing a switch element using a case having an introduction groove formed therein, FIG. 21A being a sectional view and FIG. 21B being an external perspective view. 22A and 22B are views showing a switch element using a case in which a plurality of introduction ports and introduction grooves are formed, wherein FIG. 22A is a sectional view and FIG. FIG. 23 is a cross-sectional view showing a switch element using a housing in which an introduction groove is formed that is gradually narrowed toward the inside where a reaction part is provided. FIG. 24 is a cross-sectional view showing a switch element using a casing in which a water repellent treatment portion is formed in a place other than the reaction portion. FIG. 25 is a perspective view showing a switch element using a case in which the inlet is sealed with a water-soluble insulating material. FIG. 26 is a cross-sectional view showing a switch element in which the introduction groove is sealed with a water-soluble insulating material. FIG. 27 is an exploded perspective view showing a switch element that melts and cuts the fusible conductor by heat generation in the reaction part. FIG. 28 is a diagram showing a circuit diagram configuration example of the switch element shown in FIG. 27, (A) showing a state before fusing and (B) showing a state after fusing. FIG. 29 is a diagram showing a circuit configuration example of a battery system using the switch element shown in FIG. FIG. 30 is a diagram showing a circuit configuration of a conventional battery pack.

Hereinafter, a liquid wetting sensor to which the present invention is applied, a switch element, and a battery system incorporating the switch element will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Moreover, the drawings are schematic, and the ratios of the respective dimensions may differ from the actual ones. Specific dimensions should be judged in consideration of the following description. Further, it is needless to say that the drawings include portions in which dimensional relationships and ratios are different from each other.

[Wet sensor]
As shown in FIG. 1, a liquid wetting sensor 1 to which the present invention is applied includes a reaction part 2 which generates heat when it is in contact with a liquid, and a temperature sensing part 3 whose electric characteristics change as the temperature of the reaction part 2 rises. Have. The reaction part 2 can be configured using, for example, quicklime that reacts with water to generate heat, and is arranged and held on an insulating substrate 5, as shown in FIG. 2, for example. As the temperature sensing unit 3, for example, a thermistor whose resistance value decreases as the temperature of the reaction unit 2 rises, a diode whose voltage changes, and other Peltier elements, thermocouples, bimetals, temperature sensors, etc., whose electrical characteristics have temperature dependence. Electronic components can be used. The reaction part 2 and the temperature-sensitive part 3 are thermally connected by being arranged close to each other, and the heat of the reaction part 2 heats the temperature-sensitive part 3. As a result, the temperature sensing unit 3 changes in electrical characteristics such as resistance value and output voltage.

Hereinafter, a case where the thermistor 3a is used as the temperature sensing unit 3 of the liquid leak sensor 1 will be described as an example. The thermistor 3a is formed on the insulating substrate 5, and both ends thereof are connected to the first and second external connection electrodes 6 and 7. The thermistor 3a is connected to the energization path of the electric circuit 4 via the first and second external connection electrodes 6 and 7, and the energization of the electric circuit 4 is always regulated by a high electric resistance. As the thermistor 3a, an NTC (negative temperature coefficient) thermistor or a CTR (critical temperature resistor) thermistor can be preferably used. Then, when the reaction unit 2 contacts the liquid and generates heat, the liquid wetness sensor 1 can energize the electric circuit 4 because the electric resistance value of the thermistor 3a decreases.

Further, the liquid wetting sensor 1 has a housing formed by the cover member 8 covering the insulating substrate 5. The cover member 8 is formed with an inlet 9 for guiding the liquid to the reaction section 2.

In addition, it is preferable that the liquid wetting sensor 1 is arranged so that the reaction unit 2 and the thermistor 3a are superposed on each other. For example, in the liquid wetting sensor 1, the thermistor 3a is superposed on the quicklime placed on the insulating substrate. As a result, the reaction part 2 and the thermistor 3a are thermally and closely connected to each other, and the reaction part 2 generates heat, whereby the electric resistance value of the thermistor 3a can be promptly lowered.

[Water repellent treatment]
As shown in FIG. 2, the liquid wetness sensor 1 may be provided with the water repellent treatment part 14 at a place other than the reaction part 2 or a place other than the reaction part 2 and its vicinity. For example, in the liquid wetness sensor 1, the water repellent treatment unit 14 is provided in the exposed region of the surface 5a of the insulating substrate 5 excluding the reaction unit 2 and the thermistor 3a.

The water repellent treatment portion 14 can be formed by a known method such as application of a fluorine-based coating agent or solder paste coating.

As a result, the liquid wetness sensor 1 can guide the liquid on the insulating substrate 5 to the reaction part 2 which is a non-water repellent region, accelerate the heating of the thermistor 3a, and quickly reduce the electric resistance value of the thermistor 3a. be able to.

[Example of using the liquid wetness sensor]
As shown in FIG. 3, the liquid wetness sensor 1 can be used by being incorporated in a circuit in a battery pack 10 of a lithium ion secondary battery, for example. The battery pack 10 has, for example, a battery stack 15 including battery cells of a plurality of lithium ion secondary batteries.

The battery pack 10 includes a battery stack 15, a charging/discharging control circuit 16 that controls charging/discharging of the battery stack 15, a protection element 11 that shuts off charging when the battery stack 15 is abnormal, and liquid leakage or submersion of each battery cell. The liquid wetting sensor 1 for detecting the above, and the current control element 12 for controlling the operation of the protection element 11 according to the detection result of the liquid wetting sensor 1.

The battery stack 15 includes battery cells that require control for protection from liquid leakage, submersion, etc., connected in series and/or in parallel, and is attachable/detachable via the positive electrode terminal 10 a and the negative electrode terminal 10 b of the battery pack 10. Is connected to the charging device 13 and the charging voltage from the charging device 13 is applied. The battery pack 10 charged by the charging device 13 can be operated by connecting the positive electrode terminal 10a and the negative electrode terminal 10b to an electronic device that operates on a battery.

The charge/discharge control circuit 16 includes two current control elements 17 and 18 connected in series to a current path flowing from the battery stack 15 to the charging device 13, and a control unit 19 that controls the operations of these current control elements 17 and 18. Equipped with. The current control elements 17 and 18 are composed of, for example, field effect transistors (hereinafter referred to as FETs), and the gate voltage is controlled by the control unit 19 to charge and/or discharge the current path of the battery stack 15. Controls conduction and cutoff. When the battery stack 15 is over-discharged or over-charged, the control unit 19 operates by receiving power supply from the charging device 13 and operates according to the detection result by a detection circuit (not shown) that detects the voltage of each battery cell. The operation of the current control elements 17 and 18 is controlled so as to cut off the path.

The protection element 11 is connected, for example, on a charge/discharge current path between the battery stack 15 and the charge/discharge control circuit 16, and its operation is controlled by the current control element 12. Specifically, as shown in FIGS. 4A and 4B, the protective element 11 includes an insulating substrate 26, first and second electrodes 22 and 23 formed on the insulating substrate 26, and the insulating substrate 26. A heating resistor 24 formed on the surface of the heating element, a glass layer 27 covering the heating resistor 24, a heating element lead electrode 21 laminated on the glass layer 27 and connected to the heating resistor 24, The electrode 22, the heating element lead-out electrode 21, and the second electrode 23 and the fuse element 20 mounted via the connection solder 28. The first and second electrodes 22 and 23 are connected to the first and second external connection electrodes 22a and 23a formed on the back surface of the insulating substrate 26 via castellations, respectively. The heating resistor 24 is connected to the heating element power feeding electrode 25, and is connected to the current control element 12 via the heating element power feeding electrode 25. Further, the heating resistor 24 is connected to the fuse element 20 and the charging/discharging path of the battery stack 15 by electrically connecting the heating element lead electrode 21 to the fuse element 20.

In the liquid wetness sensor 1, one end of the temperature sensing unit 3 (thermistor 3a) is connected to the battery stack 15, and the other end is connected to the current control element 12. The liquid wetting sensor 1 constantly regulates the energization from the battery stack 15 to the current control element 12 by the high resistance of the thermistor 3a. Further, in the liquid wetness sensor 1, when a liquid wet state such as a liquid leak or submersion in a battery cell occurs, the reaction part 2 generates heat and the electric resistance value of the thermistor 3a decreases, so that the current control from the battery stack 15 is performed. The element 12 can be energized.

The current control element 12 is composed of, for example, an FET, and when the battery stack 15 is energized through the liquid wetting sensor 1 in a liquid wet state, a current from the battery stack 15 flows to the protection element 11. And the protection element 11 is activated. As a result, the current control element 12 controls so that the charge/discharge current path of the battery stack 15 is cut off regardless of the switching operation of the current control elements 17 and 18.

In the battery pack 10 having the above configuration, the protection element 11 has a circuit configuration as shown in FIG. That is, the protection element 11 is energized via the fuse element 20 connected in series between the first and second electrodes 22 and 23 via the heating element lead-out electrode 21 and the connection point of the fuse element 20 to generate heat. Thus, the circuit configuration includes the heating resistor 24 that melts the fuse element 20. In the protection element 11, for example, the fuse element 20 is connected in series on the charging/discharging current path of the battery pack 10 via the first and second external connection electrodes 22a and 23a, and the heating resistor 24 feeds the heating element. It is connected to the current control element 12 via the electrode 25. The first electrode 22 of the protection element 11 is connected to one open end side of the battery stack 15 via the first external connection electrode 22a, and the second electrode 23 is connected via the second external connection electrode 23a. Is connected to the positive electrode terminal 10a side of the battery pack 10.

[Fusing process]
In the liquid wetting sensor 1 having such a circuit configuration, when it is necessary to interrupt the current path of the battery pack 10 due to liquid leakage from the battery, submersion in water, or the like, the liquid is leaked through the inlet 9 of the cover member 8. When it enters, the resistance of the thermistor 3a is lowered due to the heat generation of the reaction part 2, and the electric power of the battery stack 15 is supplied to the protection element 11 by the current control element 12 energized from the battery stack 15. As a result, in the protection element 11, the heating resistor 24 is energized to generate heat, and the fuse element 20 incorporated on the current path of the battery pack 10 is blown. Therefore, the battery pack 10 can cut off the current path of the battery pack 10 by fusing the first electrode 22 to the heating element lead-out electrode 21 to the second electrode 23 (FIG. 5B). Further, when the fuse element 20 is blown, power supply to the heating resistor 24 is also stopped.

[FET omitted type]
In the battery pack 10 using the liquid wetting sensor 1, the FET that controls the operation of the protection element 11 may be omitted, and the protection element 11 may be operated by the liquid wetting sensor 1. As shown in FIG. 6, in the battery pack 10, the temperature sensing section 3 (thermistor 3 a) of the liquid wetness sensor 1 has one end connected to the heat generating resistor 24 of the protection element 11 and the other end opening the battery stack 15. Connected to the end. The liquid wetting sensor 1 constantly regulates the energization of the heating resistor 24 by the high resistance of the thermistor 3a.

Then, the liquid wetting sensor 1 receives the liquid through the inlet 9 of the cover member 8 when it is necessary to interrupt the current path of the battery pack 10 due to liquid leakage from the battery, submersion in water, or the like. The thermistor 3a has a low resistance due to the heat generation of 2, and the power of the battery stack 15 can be supplied to the heat generating resistor 24 of the protection element 11. As a result, in the protection element 11, the heating resistor 24 is energized to generate heat, and the fuse element 20 incorporated on the current path of the battery pack 10 is blown. Therefore, the battery pack 10 can cut off the current path of the battery pack 10 by fusing the first electrode 22 to the heating element lead-out electrode 21 to the second electrode 23 (FIG. 5B). Further, when the fuse element 20 is blown, power supply to the heating resistor 24 is also stopped.

The liquid wetting sensor 1 of the present invention is not limited to the case of being used for a battery pack of a lithium ion secondary battery, but can be naturally applied to various applications requiring interruption of a current path by an electric signal. The liquid wetness sensor 1 uses various thermistors 3a as well as various electronic components having temperature-dependent electrical characteristics that constitute the temperature sensing unit 3, and appropriately adjusts the liquid depending on changes in the electrical characteristics. It is possible to control the energization of the electric circuit connected to the wetness sensor 1.

[First switch element]
Next, the switch element 30 formed using the liquid wetting sensor 1 will be described. FIG. 7 is an exploded perspective view of the switch element 30. The switch element 30 is provided on the energization path of the external circuit to shut off the conduction of the external circuit. By incorporating the liquid wetting sensor 1, the switch element 30 is in a water wet state such as submersion in water or battery leakage. By detecting this, the energization path is appropriately cut off. The switch element 30 is formed so as to be mountable by reflow or the like on a circuit board on which an external circuit is formed.

The switch element 30 includes a fuse element 31 connected to an external circuit, a heat generating resistor 32, a reaction unit 2 and a temperature sensing unit 3 which form the liquid wetting sensor 1. Further, the switch element 30 has a casing formed by an insulating substrate 33 on which the fuse element 31, the heating resistor 32, and the temperature sensing unit 3 are provided, and a cover member 34 which covers the insulating substrate 33. The cover member 34 is formed with an inlet port 36 for guiding the liquid to the reaction section 2. Hereinafter, a case where the thermistor 3a is used as the temperature sensing unit 3 of the liquid leak sensor 1 will be described as an example.

[Insulation substrate]
The insulating substrate 33 is formed in, for example, a substantially rectangular shape using an insulating member such as alumina, glass ceramics, mullite, or zirconia. In addition, the insulating substrate 33 may be made of a material used for a printed wiring board such as a glass epoxy board or a phenol board.

First and second electrodes 38 and 39 are formed on opposite ends of the insulating substrate 33. The first and second electrodes 38 and 39 are each formed of a conductive pattern such as Ag or Cu. Further, the first and second electrodes 38, 39 are continuous from the front surface 33a of the insulating substrate 33 with the first and second external connection electrodes 38a, 39a formed on the back surface 33b via a castellation (not shown). ing. The switch element 30 is a fuse element in which the first and second external connection electrodes 38a and 39a formed on the back surface 33b are connected to the connection electrodes provided on the external circuit board on which the switch element 30 is mounted. 31 is incorporated in a part of the current path formed on the circuit board.

Further, the reaction part 2 is formed on the insulating substrate 33 by disposing and holding, for example, quick lime. Further, the insulating substrate 33 constitutes the liquid wetting sensor 1 by superposing the thermistor 3 on the reaction part 2.

[Heating resistor]
The heating resistor 32 is a member having a relatively high resistance value and generating heat when energized, and is made of, for example, nichrome, W, Mo, Ru, or the like, or a material containing these. The heating resistor 32 is formed by mixing powders of these alloys, compositions, or compounds with a resin binder or the like, forming a paste, and patterning the paste on the insulating substrate 33 using a screen printing technique, followed by firing. And the like.

The fuse resistor 31 is superposed on the heating resistor 32, and the fuse element 31 is melted and blown when heat is generated by energization. One end of the heating resistor 32 is connected to the thermistor 3a, so that energization and heat generation are always regulated. Then, the heat generating resistor 32 generates heat due to an increase in the amount of energization due to a decrease in the electric resistance value of the thermistor 3a, and can blow the fuse element 31. Further, the heating resistor 32 is electrically and thermally connected by the fuse element 31 being overlapped.

[Fuse element]
In the switch element 30, the fuse element 31 is connected by the connecting solder 28 across the first electrode 38 and the second electrode 39. The fuse element 31 electrically connects the first and second electrodes 38 and 39 during normal use and constitutes a part of a current path of an external circuit in which the switch element 30 is incorporated. Then, the fuse element 31 is blown by self-heating (Joule heat) when a current exceeding the rating is applied, or is blown by the heat generated by the heating resistor 32, and cuts off between the first and second electrodes 38, 39. To do.

The fuse element 31 has a predetermined rated current value, and when the heat generated by the heating resistor 32 or a current exceeding the rated current value is applied, the fuse element 31 self-heats to quickly blow. The fuse element 31 preferably contains at least one selected from nickel, tin, and lead as a main component. In addition, in this specification, the main component means a component of 50 wt% or more based on the total mass of the material.

The fuse element 31 may have a laminated structure in which the low melting point metal layer 41 and the high melting point metal layer 42 are laminated. As the low melting point metal, it is preferable to use solder such as Pb-free solder, and as the high melting point metal, it is preferable to use Ag, Cu or an alloy containing them as a main component. By including the high melting point metal and the low melting point metal, when the switch element 30 is reflow mounted, even if the reflow temperature exceeds the melting temperature of the low melting point metal layer and the low melting point metal melts, the fuse element 31 As a result, it does not melt down.

As shown in FIG. 8, in the fuse element 31, the inner layer may be a low melting point metal and the outer layer may be a high melting point metal. By using a fusible conductor in which the entire surface of the low melting point metal layer 41 of the inner layer is covered with the high melting point metal layer 42 of the outer layer, even when a low melting point metal having a melting point lower than the reflow temperature is used, the inner layer is reflow mounted. It is possible to prevent the low melting point metal from flowing out. Also during melting, the low-melting-point metal in the inner layer is melted, so that the high-melting-point metal in the outer layer is corroded (soldered) and can be rapidly melted.

The thermistor 3a has one end connected to the heat generating resistor 32 and the other end connected to the first heat generating electrode 43. The first heating element electrode 43 is formed on the front surface 33a of the insulating substrate 33 and is continuous with the first heating element power supply electrode (not shown) formed on the back surface 33b of the insulating substrate 33 via castellation. ing. Then, the thermistor 3a regulates energization to the heating resistor 32 by a high electric resistance.

When the reaction element 2 generates heat due to contact with the liquid, the switch element 30 reduces the electric resistance value of the thermistor 3a, thereby increasing the amount of electricity supplied to the heating resistor 32 and generating heat from the heating resistor 32. The fuse element 31 is blown by. Accordingly, the switch element 30 can cut off the energization path of the external circuit.

Further, as described above, in the liquid wetness sensor 1, the reaction part 2 and the thermistor 3a are arranged so as to overlap each other. As a result, the reaction part 2 and the thermistor 3a are thermally and closely connected to each other, and the reaction part 2 generates heat, whereby the electric resistance value of the thermistor 3a can be promptly lowered.

[Cover member]
Further, in the switch element 30, a cover member 34 is attached on the surface 33a of the insulating substrate 33 on which the fuse element 31 is provided to protect the inside and prevent the molten fuse element 31 from scattering. The cover member 34 can be formed of an insulating member such as various engineering plastics and ceramics. The cover member 34 is connected to the surface 33a of the insulating substrate 33 with an insulating adhesive, and thereby covers the fuse element 31.

Further, the cover member 34 has an inlet port 36 for introducing a liquid into the reaction section 2 provided on the insulating substrate 33.

Such a switch element 30 has a circuit configuration as shown in FIG. That is, the switch element 30 melts the fuse element 31 by electrically connecting the fuse element 31 connected in series between the first and second electrodes 38 and 39 and generating heat by connecting the fuse element 31 through the connection point. This is a circuit configuration including a heating resistor 32. Further, in the switch element 30, the first heating element electrode 43, the temperature sensing portion 3 (thermistor 3 a ), the heating resistor 32, and an energization path to the heating resistor 32 reaching the fuse element 31 are formed. In addition, in the switch element 30, the first and second electrodes 38 and 39 are connected to the open end of an external circuit such as a power supply circuit, so that the fuse element 31 is incorporated in the energization path of the external circuit.

As shown in FIG. 10, the switch element 30 can be used, for example, by incorporating it in a circuit in the battery pack 10 of the lithium ion secondary battery described above. In the switch element 30, the first heating element electrode 43 is connected to one open end of the battery stack 15 that energizes the heating resistor 32, and energization to the heating resistor 32 is restricted by the thermistor 3a. In addition, in the switch element 30, the first electrode 38 is connected to the other open end side of the battery stack 15, and the second electrode 39 is connected to the positive electrode terminal 10 a side of the battery pack 10, whereby the fuse element 31. Is incorporated on the energization path of the external circuit.

Then, in the switch element 30, when the liquid enters through the introduction port 36 provided in the cover member 34 and the reaction part 2 comes into contact with the liquid to generate heat, the electric resistance value of the thermistor 3a is reduced, and thus the battery stack. Power is supplied from 15 to heat the heating resistor 32. As a result, in the switch element 30, the fuse element 31 incorporated on the current path of the battery pack 10 is melted, and the molten conductor of the fuse element 31 causes the heating element lead-out electrode 21 having the high wettability and the first and second electrodes. The fuse element 31 is blown by being drawn to the electrodes 38 and 39. Therefore, as shown in FIG. 9B, the switch element 30 can cut off the charge/discharge path of the battery stack 15.

Here, the switch element 30 constitutes a part of an energization path to the heat generating resistor 32 by connecting the fuse element 31 to the heat generating resistor 32. Therefore, in the switch element 30, when the fuse element 31 is melted and the connection with the external circuit is cut off, the energization path to the heating resistor 32 is also cut off, so that the heat generation can be stopped.

[Water repellent treatment]
In addition, as shown in FIG. 7, the switch element 30 may be provided with the water repellent treatment part 35 at a place other than the reaction part 2 or a place other than the reaction part 2 and its vicinity. For example, the switch element 30 may be formed by removing the reaction portion 2, the heating resistor 32, the first and second electrodes 38 and 39, the first heating element electrode 43, and the exposed area of the surface 33a of the insulating substrate 33 excluding the thermistor 3a. A water treatment unit 35 is provided.

The water repellent portion 35 can be formed by a known method such as application of a fluorine-based coating agent or solder paste coating.

As a result, the switch element 30 can guide the liquid on the insulating substrate 33 to the reaction part 2 which is a non-water repellent region, and can accelerate the heating of the thermistor 3a and accelerate the fusing of the fuse element 31.

[FET switching]
Further, as shown in FIG. 11, the switch element 30 connects the temperature sensing unit 3 (thermistor 3a) between the battery stack 15 and the current control element 12 such as FET, and controls one end of the heating resistor 32 to control the current. It may be connected to the element 12. In this case, the thermistor 3a has one end connected to the open end of the battery stack 15 via the third external connection electrode 44 and the other end connected to the current control element 12 via the fourth external connection electrode 45. Has been done. The switch element 30 constantly regulates energization from the battery stack 15 to the current control element 12 by the high resistance of the thermistor 3a. Further, one end of the heat generating resistor 32 is connected to the current control element 12 via the first heat generating electrode 43, and energization from the battery stack 15 is restricted.

Then, when a liquid wet state such as liquid leakage or submersion of the battery cell occurs in the switch element 30, the liquid enters through the inlet 36 provided in the cover member 34, and the reaction unit 2 comes into contact with the liquid to generate heat. .. As a result, the electric resistance value of the thermistor 3a decreases, so that the current control element 12 is energized from the battery stack 15. The current control element 12 is switched so that the electric power of the battery stack 15 is supplied to the heating resistor 32, whereby the switching element 30 causes the heating resistor 24 to be energized and generate heat, so that the current path of the battery pack 10 is controlled. The fuse element 31 incorporated in the fuse is blown, and the current path of the battery pack 10 can be cut off. Further, when the fuse element 31 is blown, power supply to the heating resistor 32 is also stopped.
[Insulating layer/Extractor for heating element]

As shown in FIG. 12, in the switch element 30, an insulating layer 50 is provided so as to cover the heating resistor 32, and a heating element lead electrode 51 is provided so as to face the heating resistor 32 via the insulating layer 50. May be formed. The heating element lead-out electrode 51 is connected by overlapping the fuse element 31, so that the heating resistor 32 is overlapped with the fuse element 31 via the insulating layer 50 and the heating element lead-out electrode 51. The insulating layer 50 is provided in order to protect and insulate the heating resistor 32 and to efficiently transfer the heat of the heating resistor 32 to the fuse element 31, and is made of, for example, a glass layer. In the switch element 30, the insulating layer 50 may be laminated between the heating resistor 32 and the insulating substrate 33 in order to efficiently transfer the heat of the heating resistor 32 to the fuse element 31.

In this case, one end of the heating resistor 32 is connected to the heating member lead electrode 51, and the other end is connected to the first heating member electrode 43 via the thermistor 3a. The heating element lead-out electrode 51 is formed on the surface 33a of the insulating substrate 33 and is laminated on the insulating layer 50 facing the heating resistor 32 and the lower layer portion 51a connected to the heating resistor 32, and is also a fuse. It has the upper layer part 51b connected with the element 31. As a result, the heat generating resistor 32 is electrically connected to the fuse element 31 via the heat generating element lead electrode 51. Further, the heating resistor 32 is thermally connected to the fuse element 31 via the insulating layer 50 and the heating element lead electrode 51. The heating element lead-out electrode 51 is heated by being opposed to the heating resistor 32 with the insulating layer 50 interposed therebetween, so that the fuse element 31 can be melted and the molten conductor can be easily aggregated.

Further, the switch element 30 constitutes a part of an energization path to the heating resistor 32 by connecting the fuse element 31 to the heating element lead-out electrode 51. Therefore, in the switch element 30, when the fuse element 31 is melted and the connection with the external circuit is cut off, the energization path to the heating resistor 32 is also cut off, so that the heat generation can be stopped.

[Electrification path/Power supply path]
Further, in the switch element to which the present invention is applied, the energization path of the fuse element 31 and the power supply path to the heating resistor 32 may be separated. For example, in the switch element 30 shown in FIG. 13, the heating resistor 32 is superposed on the fuse element 31 via the insulating layer 50, so that the switch element 30 is electrically independent of the fuse element 31 and is thermally connected thereto. The heating resistor 32 has one end connected to the thermistor 3a and the other end connected to the second heating electrode 52. The second heating element electrode 52 is formed on the front surface 33a of the insulating substrate 33 and is continuous with the second heating element feeding electrode (not shown) formed on the back surface 33b of the insulating substrate 33 via castellation. ing.

In the switch element 30 shown in FIG. 13, the heating resistor 32 may be formed on the back surface 33b opposite to the surface 33a of the insulating substrate 33 on which the first and second electrodes 38 and 39 are formed, Alternatively, it may be formed adjacent to the fuse element 31 and the thermistor 3a on the surface 33a of the insulating substrate 33. Further, in the switch element 30, the heating resistor 32 may be formed inside the insulating substrate 33.

As shown in FIG. 14, such a switching element 30 includes a first heating element electrode 43, a temperature sensing unit 3 (thermistor 3 a ), a heating resistor 32, and a heating resistor 32 reaching the second heating element electrode 52. A power supply path 53 to the power source is formed. In the power feeding path 53 of the heating resistor 32, the first and second heating element electrodes 43 and 52 are connected to the power feeding circuit, and energization is restricted by the thermistor 3a. Further, in the switch element 30, an energization path 54 of the fuse element 31 is formed between the first and second electrodes 38, 39. The energization path 54 is incorporated in the energization path of the external circuit by connecting the first and second electrodes 38 and 39 to the open ends of the external circuit.

When the reaction part 2 contacts the liquid and generates heat, the switch element 30 lowers the electric resistance value of the thermistor 3 a, so that the power supply path 53 is energized and the heating resistor 32 can be heated. As a result, in the switch element 30, the fuse element 31 is melted by the heat of the heating resistor 32, and the external circuit can be cut off.

Further, in the switch element 30, as shown in FIG. 15, the power supply path 31 to the heating resistor 32 and the energization path 32 of the fuse element 31 may be arranged in parallel. In the configuration shown in FIG. 15 as well, in the switch element 30, when the reaction part 2 comes into contact with a liquid to generate heat, the electric resistance value of the thermistor 3a decreases, so that the power feeding path 31 is energized and the heating resistor 32 is turned on. Can generate heat. As a result, in the switch element 30, the fuse element 31 is melted by the heat of the heating resistor 32, and the external circuit can be cut off.

The first and second electrodes 38 and 39, the heating element lead-out electrode 51, and the first and second heating element electrodes 43 and 52 described above are formed by a conductive pattern such as Ag or Cu, and are appropriately formed on the surface. It is preferable that a protective layer such as Sn plating, Ni/Au plating, Ni/Pd plating, or Ni/Pd/Au plating is formed on. Thereby, the surface is prevented from being oxidized, and the first and second electrodes 38 and 39, the heating element lead-out electrode 51, and the first and second heating elements electrodes made of the connecting material such as the connecting solder 28 of the fuse element 31. The erosion of 43 and 52 can be suppressed.

[Case]
Next, the housing of the liquid wetting sensor 1 and the switch element 30 will be described. The case of the switch element 30 will be described below, but the liquid wetting sensor 1 may have the same configuration. As described above, the switch element 30 has a casing formed of the insulating substrate 33 and the cover member 34 connected to the insulating substrate 33. By providing the cover member 34, the switch element 30 protects the fuse element 31, the reaction part 2 and the temperature sensing part 3 from a mechanical disturbance or the like received from the outside, and the fuse element 31 self-heats to generate arc discharge. It is possible to prevent the molten metal from scattering around when it is melted and cut.

The cover member 34 is provided with an inlet port 36 for guiding the liquid to the reaction section 2. The switch element 30 irreversibly cuts off the fuse element 31 by the liquid flowing into the reaction section 2 through the inlet port 36 provided in the cover member 34.

As shown in FIG. 16A, for example, the cover member 34 is made of a polyhedron, and one introduction port 36 is provided on one surface. When the switch element 30 is formed as a chip component mounted on a circuit board on which an external circuit is formed, the introduction port 36 may be provided on the top surface 34a of the cover member 34 opposite to the mounting surface of the housing. preferable. By providing the inlet 36 on the top surface 34a, it is possible to efficiently take the liquid into the housing and hold the liquid in the reaction portion 2 when the water is wet, and to interrupt the fuse element 31. Of course, the cover member 34 may have the inlet 36 formed on a surface other than the top surface 34a, for example, the side surface 34b. As shown in FIG. 16B, the cover member 34 may have a plurality of inlets 36 formed on the top surface 34a or a plurality of inlets 36 formed on the side surface 34b. The cover member 34 can be more easily introduced into the reaction section 2 by providing a plurality of introduction ports 36.

In addition, the cover member 34 may be formed of a polyhedron, for example, as shown in FIG. 16C, and the introduction port 36 may be provided on a plurality of surfaces, for example, the top surface 34a and the side surface 34b. Further, as shown in FIG. 16D, the cover member 34 may have one or a plurality of inlets 36 formed on a plurality of surfaces, respectively.

Further, in the switch element 30, the cover member 34 may be formed in a tubular shape, and the introduction ports 36 may be formed at any position and in any number. FIG. 17 is an external perspective view of the switch element 30 in which the cover member 34 is formed in a cylindrical shape and a plurality of introduction ports 36 are formed over the entire circumference. The cover member 34 may be formed in a hollow polygonal column shape. By forming the cover member 34 into a hollow columnar shape or a prismatic shape, the introduction port 36 can be formed without being influenced by a surface or an angle according to the arrangement of the switch element 30, a liquid infiltration path, or the like.

The switch element 30 shown in FIG. 17 has a first external connection electrode 38a and a second external connection electrode 39a for energizing the fuse element 31, and a first external connection electrode 43 connected to the first external connection electrode 38a. The heating element power supply electrode 43a is formed so as to project from the outer peripheral surface of the cover member 34.

Further, the cover member 34 may form a discharge port for discharging the liquid that has entered through the introduction port 36. FIG. 18 is an external perspective view showing the switch element 30 in which the inlet 36 is formed on the top surface 34a of the cover member 34 formed of a polyhedron and the outlet 37 for discharging the liquid is formed on the side surface 34b. By forming the discharge port 37, a large amount of liquid penetrates into the switch element 30 to cool the reaction part 2 and the temperature sensing part 3 and prevent the resistance value of the thermistor 3a from decreasing. It is possible to prevent a situation in which the change in the electrical characteristics of No. 3 is obstructed and the fusing action of the fuse element 31 is delayed.

The outlet 37 is preferably formed smaller than the inlet 36. By making the discharge port 37 relatively small, it is possible to prevent the liquid that has infiltrated into the switch element 30 from being excessively discharged, and conversely prevent the heat generating action of the reaction part 2 and the fusing of the fuse element 31 from being delayed. ..

Further, it is preferable that the discharge port 37 is provided at the same height as the position where the reaction unit 2 is provided, or above the position where the reaction unit 2 is provided. For example, as shown in FIG. 19, when the cover member 34 is formed in a polyhedral shape and is formed as a chip component to be mounted on a circuit board, the discharge port 37 has a reaction part 2 on a side surface 34 b of the cover member 34. It is preferably provided at the same height as or above the provided position. As a result, the liquid that has entered the switch element 30 is drained to the extent that it has entered above the reaction section 2 and remains in the reaction section 2, so that the action of the reaction section 2 is ensured and the liquid inside the switch element 30 is ensured. It is possible to prevent the reaction part 2 and the temperature sensing part 3 from being cooled by a large amount of the liquid that has entered, and to prevent the heat generation effect of the reaction part 2 and the delay of the fusing of the fuse element 31 from being delayed.

The inlet 36 for introducing the liquid and the outlet 37 for discharging the liquid may have any shape such as a circular shape or a rectangular shape. Further, the inlet 36 and the outlet 37 may be formed in a slit shape as shown in FIG. By forming the introduction port 36 in a slit shape, it is possible to introduce the liquid in a wider range and quickly react the reaction portion 2 to melt the fuse element 31. Further, by forming the discharge port 37 in the shape of a slit, the excess liquid that has entered the switch element 30 can be quickly drained, and the heat generation effect of the reaction part 2 and the progress of fusing of the fuse element 31 are delayed. Can be prevented.

In addition, the cover member 34 may be provided with a slit-shaped introduction port 36 on the top surface 34 a and an introduction groove 40 for introducing the liquid to the reaction section 2. As shown in FIGS. 21A and 21B, the introduction groove 40 extends from the introduction port 36 having the groove wall 40a formed on the top surface 34a to the vicinity of the reaction portion 2. Accordingly, the switch element 30 can reliably guide the liquid that has entered the inlet 36 to the reaction section 2 without flowing into a place other than the reaction section 2. In addition, the switch element 30 can prevent the liquid that has entered the introduction port 36 from being dissipated into the housing and delaying the heat generation effect of the reaction part 2 and the progress of the fusing of the fuse element 31.

Further, as shown in FIG. 21B, the cover member 34 may extend the introduction groove 40 to the side surface 34b and be continuous with the discharge port 37 formed on the side surface 34b. As a result, the switch element 30 can efficiently guide the liquid that has entered through the introduction port 36 to the reaction section 2 and efficiently drain the excess liquid from the discharge port 37.

As shown in FIGS. 22A and 22B, a plurality of introduction grooves 40 may be formed. By forming a plurality of introduction grooves 40, the liquid can be guided over the entire width of the reaction section 2.

Further, as shown in FIG. 23, the introduction groove 40 may be gradually narrowed from the opening of the introduction port 36 facing the top surface 34a to the inside where the reaction portion 2 is provided. By narrowing the introduction groove 40 toward the reaction section 2, the liquid that has entered through the opening of the introduction port 36 can be efficiently guided to the reaction section 2 by the capillary phenomenon.

Further, the switch element 30 may be subjected to water repellent treatment at a place other than the reaction part 2 to guide the liquid to the reaction part 2. For example, as shown in FIG. 24, the switch element 30 may be formed with a water repellent treatment portion 46 in which water repellent treatment is applied to the inlet 36 or the groove wall 40 a of the inlet 36 and the inlet groove 40. The water repellent portion 46 can be formed by a known method such as application of a fluorine-based coating agent or solder paste coating.

As a result, the switch element 30 can efficiently guide the liquid that has entered through the inlet 36 to the reaction section 2. Further, by applying a water repellent treatment to the introduction port 36 and the introduction groove 40, a small amount of liquid is not repelled to enter the switch element 30 except in a wet state where the switch element 30 should be operated. It is also possible to prevent and secure reliability as a sensor or a switch.

Further, in the switch element 30, the inner wall of the cover member 34 may be subjected to water repellent treatment. By applying a water repellent treatment to the inner wall of the cover member 34, the liquid that has entered the switch element 30 can be efficiently guided to the reaction section 2 and the reaction section 2 can be promptly acted.

Further, as shown in FIG. 25, the switch element 30 may be closed by attaching a sheet body formed of a water-soluble sealing material 47 that dissolves the introduction port 36 in a liquid to the top surface 34a. Further, as shown in FIG. 26, the switch element 30 may close the introduction groove 40 with a water-soluble sealing material 47 that dissolves in a liquid. Examples of the water-soluble sealing material 47 include natural polymers such as agar and gelatin, semi-synthetic polymers such as cellulose and starch, and synthetic polymers such as polyvinyl alcohol. These contract or dissolve when they come into contact with a liquid. It is preferable to adjust the degree of polymerization to be used, since the polymer has a high molecular weight and has a property of expanding without being dissolved. Further, when a water-soluble solid substance such as sugar cube is used as the liquid-soluble material, it is dissolved or its volume is reduced by coming into contact with the liquid.

Further, assuming a liquid electrolyte such as ethylene carbonate filled in the battery cell as a liquid, in the case of a switch element that operates in response to electrolyte leakage, the material of the water-soluble sealing material 47 is ABS, polyacrylonitrile, Polyvinylidene fluoride or saturated polyester such as PET, PTT and PEN can be used. When these water-soluble materials also have a high molecular weight, the dissolution rate may decrease, and the reaction rate as the switch element 30 may decrease. Therefore, when priority is given to the reaction rate, it is preferable to adjust the degree of polymerization before use.

By closing the introduction port 36 and the introduction groove 40 with the water-soluble sealing material 47, a small amount of liquid is not repelled to enter the switch element 30 except in a wet state where the switch element 30 should be operated. It is possible to prevent operation and ensure reliability as a sensor or a switch.

[Second switch element]
Next, the second switch element will be described. In the following description, the same members as those of the liquid wetting sensor 1 and the switch element 30 described above are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 27 is an exploded perspective view of the switch element 60. The switch element 60 is arranged on the energization path of the external circuit to cut off the conduction of the external circuit. The switch element 60 includes a fuse element 61 connected to an external circuit, and a reaction part 2 that generates heat when touched with a liquid. The heat generation of the reaction part 2 melts the fuse element 61.

Further, the switch element 60 has a casing formed by the insulating substrate 33 on which the fuse element 61 and the reaction section 2 are provided, and the cover member 34 covering the insulating substrate 33. The cover member 34 is formed with an inlet port 36 for guiding the liquid to the reaction section 2. First and second electrodes 38 and 39 are formed on opposite ends of the insulating substrate 33. In the switch element 60, the first and second external connection electrodes 38a and 39a continuous with the first and second electrodes 38 and 39 are connected to the connection electrodes provided on the external circuit board on which the switch element 60 is mounted. As a result, the fuse element 61 is incorporated in a part of the current path formed on the circuit board.

Further, the reaction part 2 is formed on the insulating substrate 33 by disposing and holding, for example, quick lime. By disposing the fuse element 61 near the reaction part 2, the reaction part 2 and the fuse element 61 are thermally connected. For example, in the reaction part 2, the fuse element 61 is arranged so as to overlap.

[Fuse element]
In the switch element 60, the fuse element 61 is connected to the first electrode 38 and the second electrode 39 by connecting solder. The fuse element 61 electrically connects the first and second electrodes 38 and 39 during normal use and constitutes a part of a current path of an external circuit in which the switch element 60 is incorporated. Then, the fuse element 61 is blown by self-heating (Joule heat) when a current exceeding the rating is applied, or is blown by the heat generation of the reaction part 2 to cut off between the first and second electrodes 38, 39. ..

The fuse element 61 has a predetermined rated current value, and when heat is generated in the reaction part 2 or a current exceeding the rated current value is applied, the fuse element 61 is quickly blown by self-heating. The fuse element 61 preferably contains at least one selected from nickel, tin, and lead as a main component. The fuse element 61 may have a laminated structure in which the low melting point metal layer 41 and the high melting point metal layer 42 are laminated in the same manner as the fuse element 31 described above.

Such a switch element 60 has a circuit configuration as shown in FIG. That is, the switch element 60 has a circuit configuration including a fuse element 61 connected in series between the first and second electrodes 38 and 39, and a reaction section 2 that melts the fuse element 61 by generating heat due to liquid wetting. is there. Further, in the switch element 60, the first and second electrodes 38 and 39 are connected to the open end of the external electric circuit 4 such as a power supply circuit, so that the fuse element 61 is provided on the energization path of the electric circuit 4. It is built in, and the rated current is made to flow to energize the electric circuit 4.

The switch element 60 is self-heated (Joule heat) when a current exceeding the rating flows through the fuse element 61, and is heat-generated by the reaction part 2 when liquid enters the switch element 60. , The fuse element 61 is blown and the electric circuit 4 is cut off (FIG. 28(B)).

As shown in FIG. 29, the switch element 60 can be used, for example, by incorporating it in the circuit in the battery pack 10 of the above-described lithium ion secondary battery. In the switch element 60, the first electrode 38 is connected to the other open end side of the battery stack 15, and the second electrode 39 is connected to the positive electrode terminal 10a side of the battery pack 10, whereby the fuse element 61 is connected. It is installed on the energizing path of the external circuit.

When the switch element 60 is heated by the liquid infiltrating through the inlet 36 provided in the cover member 34 and the reaction portion 2 coming into contact with the liquid, the fuse element 61 incorporated in the current path of the battery pack 10 is generated. Is melted and the molten conductor of the fuse element 61 is attracted to the first and second electrodes 38 and 39 having high wettability, so that the fuse element 61 is melted. Therefore, as shown in FIG. 28B, the switch element 60 can cut off the charge/discharge path of the battery stack 15.

[Water repellent treatment]
As shown in FIG. 27, the switch element 60 has a water repellent treatment part 35 provided in a place other than the reaction part 2 or in a place other than the reaction part 2 and its vicinity in the same manner as the switch element 30 described above. Good. For example, in the switch element 60, the water repellent treatment portion 35 is provided in the exposed region of the surface 33a of the insulating substrate 33 excluding the reaction portion 2, the first and second electrodes 38 and 39.

As a result, the switch element 60 can guide the liquid on the insulating substrate 33 to the reaction part 2 which is a non-water repellent region, and can accelerate the heating of the fuse element 61 and promote the fusing.

In the switch element 60 as well, similar to the switch element 30 described above, the cover member 34 that constitutes the housing is made of a polyhedron, and one inlet port 36 is provided on one surface (FIG. 16 ( See A)). Further, the cover member 34 may have a plurality of inlets 36 formed on the top surface 34a (see FIG. 16B), or may have a plurality of inlets 36 formed on the side surface 34b. Further, the cover member 34 may be provided with the introduction port 36 on a plurality of surfaces, for example, the top surface 34a and the side surface 34b (see FIG. 16C). Further, the cover member 34 may have one or a plurality of inlets 36 formed on a plurality of surfaces (see FIG. 16D).

In the switch element 60, like the switch element 30, the cover member 34 may be formed in a tubular shape, and the introduction port 36 may be formed in any position and in any number (see FIG. 17 ).

Further, the switch element 60 may have a discharge port 37 for discharging the liquid that has entered the cover member 34 through the introduction port 36, similarly to the switch element 30 (see FIG. 18). Further, it is preferable that the outlet 37 is provided at the same height as the position where the reaction unit 2 is provided or above the position where the reaction unit 2 is provided (see FIG. 19 ). The inlet 36 for introducing the liquid and the outlet 37 for discharging the liquid may have any shape such as a circular shape or a rectangular shape. Further, the inlet 36 and the outlet 37 may be formed in a slit shape (see FIG. 20).

Further, the switch element 60, similarly to the switch element 30, may be provided with the slit-shaped introduction port 36 on the top surface 34a of the cover member 34 and the introduction groove 40 for guiding the liquid to the reaction section 2 (FIG. 21). (See (A) and (B)).

A plurality of introduction grooves 40 may be formed (see FIGS. 22A and 22B). The introduction groove 40 may be gradually narrowed from the opening of the introduction port 36 facing the top surface 34a to the inside where the reaction portion 2 is provided (see FIG. 23). By narrowing the introduction groove 40 toward the reaction section 2, the liquid that has entered through the opening of the introduction port 36 can be efficiently guided to the reaction section 2 by the capillary phenomenon.

Further, similarly to the switch element 30, the switch element 60 may apply a water repellent treatment to a place other than the reaction section 2 to guide the liquid to the reaction section 2 (see FIG. 24). The switch element 60 may have a water-repellent treatment portion 46 in which the inlet 36 or the groove wall 40 a of the inlet 36 and the inlet groove 40 is subjected to a water-repellent treatment. The water repellent portion 46 can be formed by a known method such as application of a fluorine-based coating agent or solder paste coating.

As a result, the switch element 60 can efficiently guide the liquid that has entered through the inlet 36 to the reaction section 2. Further, by applying a water-repellent treatment to the introduction port 36 and the introduction groove 40, a small amount of liquid is not repelled to enter the switch element 60 except in a wet state where the switch element 60 should be operated. It is also possible to prevent and secure reliability as a sensor or a switch.

Further, in the switch element 60, similarly to the switch element 30, the inner wall of the cover member 34 may be subjected to water repellent treatment. By applying a water repellent treatment to the inner wall of the cover member 34, the liquid that has entered the switch element 60 can be efficiently guided to the reaction section 2 and the reaction section 2 can be promptly acted.

Further, like the switch element 30, the switch element 60 may be closed by attaching a sheet body formed of a water-soluble sealing material 47 that dissolves the introduction port 36 in a liquid to the top surface 34a (FIG. 25). Further, the switch element 60 may close the introduction groove 40 with a water-soluble sealing material 47 that dissolves in a liquid, similarly to the switch element 30 (see FIG. 26).

By closing the introduction port 36 and the introduction groove 40 with the water-soluble sealing material 47, a small amount of liquid is not repelled to enter the switch element 60 except in a wet state where the switch element 60 should be operated. It is possible to prevent operation and ensure reliability as a sensor or a switch.

1 Liquid Wetting Sensor, 2 Reaction Part, 3 Thermistor, 4 Electric Circuit, 5 Insulating Substrate, 6 First External Connection Electrode, 7 Second External Connection Electrode, 8 Cover Member, 9 Inlet Port, 10 Battery Pack, 11 Protection Element, 12 current control element, 13 charging device, 15 battery stack, 16 charge/discharge control circuit, 17 current control element, 18 current control element, 19 control section, 20 fuse element, 21 heating element lead electrode, 22 first electrode , 23 second electrode, 24 heating element, 25 heating element feeding electrode, 26 insulating substrate, 27 glass layer, 28 connection solder, 30 switch element, 31 fuse element, 32 heating resistor, 33 insulating substrate, 34 cover Member, 35 Water repellent treatment part, 36 Inlet port, 37 Outlet port, 38 First electrode, 39 Second electrode, 40 Inlet groove, 41 Low melting point metal layer, 42 High melting point metal layer, 43 First heating element Electrode, 44 Third external connection electrode, 45 Fourth external connection electrode, 46 Water repellent treatment part, 47 Water-soluble encapsulant, 50 Insulating layer, 51 Heating element extraction electrode, 52 Second heating element electrode, 53 Power supply path, 54 energization path, 60 switch element, 61 fuse element

Claims (42)

A reaction part that generates heat by touching liquid,
A liquid wetting sensor having a temperature sensitive portion whose electric characteristics change with a change in temperature of the reaction portion. The reaction part has calcium oxide (CaO: quicklime),
The liquid wetness sensor according to claim 1, wherein the liquid is mainly composed of water. The liquid wetness sensor according to claim 1 or 2, wherein the reaction part and the temperature sensing part are overlapped with each other. The liquid wetness sensor according to claim 1, wherein the temperature sensing unit is a thermistor, a diode, a thermocouple, a bimetal, or a temperature sensor. A fusible conductor connected to an external circuit,
A heating resistor,
A reaction part that generates heat by touching liquid,
A temperature-sensing portion, which is connected to the heat-generating resistor and whose electric characteristics change with a change in temperature of the reaction portion,
A switch element for fusing the fusible conductor due to heat generation of the heating resistor whose energization amount has increased due to a change in electrical characteristics of the temperature sensing portion. The reaction part has calcium oxide (CaO: quicklime),
The switch element according to claim 5, wherein the liquid contains water as a main component. The switch element according to claim 5, wherein the reaction part and the temperature sensing part are overlapped with each other. The switch element according to claim 5, wherein the temperature sensing unit is a thermistor, a diode, a thermocouple, a bimetal, or a temperature sensor. The fusible conductor is connected to a power circuit,
The switch element according to claim 5, wherein the heating resistor is electrically connected to an energization path of the fusible conductor. The fusible conductor is connected to a power circuit,
The switch element according to claim 5, wherein the heating resistor is connected to a power supply circuit in parallel with the fusible conductor. Furthermore, a housing including the fusible conductor, the heating resistor, the reaction section, and the temperature sensing section is provided,
The switch element according to any one of claims 5 to 10, wherein the housing is provided with an inlet for introducing the liquid to the reaction part. The switch element according to claim 11, wherein the housing is formed of a polyhedron, and one or more of the introduction ports are provided on one or more of the surfaces. The switch element according to claim 11, wherein the housing is formed in a tubular shape, and one or a plurality of the introduction ports are formed on a side surface. The switch element according to any one of claims 11 to 13, wherein the housing is provided with a discharge port for discharging the inflowing liquid. The switch element according to claim 14, wherein the discharge port is provided at the same height as a position where the reaction unit is provided, or above the position where the reaction unit is provided. The switch element according to any one of claims 11 to 15, wherein the introduction port is provided with an introduction groove for guiding the liquid to the reaction section. The switch element according to claim 16, wherein the introduction groove is gradually narrowed from the opening of the introduction port toward the inside. The switch element according to any one of claims 11 to 17, wherein the introduction port of the casing has a water repellent treatment. The switch element according to claim 16 or 17, wherein the introduction groove of the casing is subjected to water repellent treatment. The switch element according to any one of claims 11 to 19, wherein an inner wall of the housing is subjected to a water repellent treatment. 21. The switch element according to claim 11, wherein the inlet is closed with a liquid-soluble material that dissolves in the liquid. The switch element according to claim 16 or 17, wherein a liquid-soluble material that dissolves in the liquid is arranged in the introduction groove. A battery cell,
A fusible conductor connected on the charge/discharge path of the battery cell,
A heating resistor,
A reaction part that generates heat by touching liquid,
A temperature-sensing section connected on the energization path of the heating resistor, the electric characteristics of which change with the temperature change of the reaction section,
A battery system in which the fusible conductor is blown by the heat generation of the heating resistor whose energization amount has increased due to a change in the electrical characteristics of the temperature sensing portion. A battery cell,
A fusible conductor connected on the charge/discharge path of the battery cell,
A heating resistor,
A reaction part that generates heat by touching liquid,
A temperature-sensitive part whose electric characteristics change as the temperature of the reaction part changes,
Equipped with a current control element for controlling energization to the heating resistor,
The temperature sensing section and the current control element are connected,
A battery system in which the current control element is energized due to a change in electrical characteristics of the temperature sensing portion, energization of the heating resistor is started, and the fusible conductor is melted by heat generation of the heating resistor. A fusible conductor connected to an external circuit,
With a reaction part that generates heat by touching liquid,
A switch element that melts and cuts the fusible conductor by heat generated in the reaction part. The reaction part has calcium oxide (CaO: quicklime),
The switch element according to claim 25, wherein the liquid contains water as a main component. The switch element according to claim 25 or 26, wherein the reaction portion and the fusible conductor are overlapped with each other. Furthermore, the fusible conductor, and a housing containing the reaction part are provided,
The switch element according to any one of claims 25 to 27, wherein the housing is provided with an introduction port that guides the liquid to the reaction section. 29. The switch element according to claim 28, wherein the housing is formed of a polyhedron, and one or a plurality of the inlets are provided on one or a plurality of surfaces. 29. The switch element according to claim 28, wherein the housing is formed in a tubular shape, and one or more of the introduction ports are formed on a side surface. 31. The switch element according to claim 28, wherein the housing is provided with a discharge port for discharging the inflowing liquid. 32. The switch element according to claim 31, wherein the discharge port is provided at the same height as a position where the reaction unit is provided, or above the position where the reaction unit is provided. 33. The switch element according to claim 28, wherein the introduction port is provided with an introduction groove for guiding the liquid to the reaction section. 34. The switch element according to claim 33, wherein the introduction groove is gradually narrowed from the opening of the introduction port toward the inside. The switch element according to any one of claims 28 to 34, wherein the housing has a water repellent treatment applied to the inlet. The switch element according to claim 33 or 34, wherein the introduction groove of the casing is subjected to a water repellent treatment. The switch element according to any one of claims 28 to 36, wherein an inner wall of the housing is subjected to a water repellent treatment. 38. The switch element according to claim 28, wherein the inlet is closed with a liquid-soluble material that dissolves in the liquid. The switch element according to claim 33 or 34, wherein a liquid-soluble material that dissolves in the liquid is arranged in the introduction groove. A battery cell,
A fusible conductor connected on the charge/discharge path of the battery cell,
With a reaction part that generates heat by touching liquid,
A battery system in which the fusible conductor is melted by the heat generated in the reaction part. The liquid wetness sensor according to claim 1, wherein the temperature sensing unit is a Peltier device. The switch element according to claim 5, wherein the temperature sensing portion is a Peltier element.

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