KR102378642B1 - Fuse element - Google Patents

Abstract

A fuse element capable of safely opening an electric circuit against an abnormality such as water leakage is provided. A fuse element comprising a fuse element (11) and an electrode (12) disposed close to the fuse element (11) and made of a metal having a smaller ionization tendency than the fuse element (11). In this way, for example, when water enters between the fuse element 11 and the electrode 12, the current rating of the fuse element 11 is lowered by the electrolytic action, so that the electric circuit can be opened safely.

Description

fuse element

The present invention relates to a fuse element that is fused by Joule heat to open an electric circuit when a current greater than a rated current flows. This application claims priority on the basis of Japanese Patent Application No. 2014-114535 for which it applied in Japan on June 3, 2014, This application is used for this application by reference.

In recent years, lithium ion secondary batteries have been adopted in most of mobile phones, notebook PCs, and the like. Since lithium ion secondary batteries have high weight energy density, in order to ensure the safety of users and electronic devices, in general, several protection circuits such as overcharge protection and overdischarge protection are built into the battery pack, and in certain cases, the battery pack It has a function to block the output of However, when the positive electrode/negative electrode insulation fitting portion of the battery is corroded by being wet with water, the pressure inside the battery leaks, and the safety valve does not function properly, and there is a risk of leading to an explosion accident.

There is a case that a warning is issued by attaching a seal that detects a wet trace with respect to water wetness (for example, refer to Patent Document 1), but since the use of the battery is not limited, migration (insulation by water wetness of the circuit board) deterioration) or a circuit malfunction due to a short circuit may occur. Moreover, there exists a possibility that the same problem as the above may arise also about the leakage of electrolyte solution accompanying abnormality of a battery.

Japanese Laid-Open Patent Publication No. 11-144695 Japanese Laid-Open Patent Publication No. 2000-162081

The present invention has been proposed in view of such a conventional situation, and provides a fuse device capable of safely opening an electric circuit against abnormalities such as water wetness and battery fluid leakage.

In order to solve the above-mentioned problem, the fuse element which concerns on this invention is provided with the electrode which is arrange|positioned adjacent to the said fuse element and consists of a metal with a smaller ionization tendency than the said fuse element, It is characterized by the above-mentioned.

According to the present invention, for example, when water enters between the fuse element and the electrode, the electrical resistance of the fuse element increases due to the electrostatic action and the rated current value decreases, so that the electric circuit is safely opened. can do it

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the structural example of a fuse element.
Fig. 2 is a perspective view schematically showing a fuse element before electric corrosion.
Fig. 3 is a perspective view schematically showing a fuse element after electric corrosion.
4 is a perspective view showing a configuration example of a fuse element in which a plurality of fuse elements are arranged in parallel.
5 is a cross-sectional view showing a configuration example of a fuse element in which a plurality of fuse elements are arranged in parallel.
6 : is a block diagram which shows the application example in which the fuse element was used for the circuit in the battery pack of a lithium ion secondary battery.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail in the following order, referring drawings.

1. Structure example of fuse element

2. Application example of fuse element

<1. Structure example of fuse element>

The fuse element which concerns on this embodiment is provided with the fuse element and the electrode which is arrange|positioned adjacent to a fuse element, and consists of a metal with a smaller ionization tendency than a fuse element. Since the fuse element and the electrode are adjacent to each other, liquid enters between the fuse element and the electrode during abnormalities such as water wetness or battery liquid leakage, and the fuse element is corroded. Thereby, since an electrical resistance rises and a rated current value falls, it is self-interrupted by the energizing current to a fuse element, and an electric circuit can be opened safely.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the structural example of a fuse element. The fuse element 10 is provided with the fuse element 11 which consists of a flat plate, and electrodes 12A, 12B arrange|positioned opposingly to both surfaces of the center part of the fuse element 11. As shown in FIG. The fuse element 11 and the electrode 12 are close to each other so that water can penetrate, and it is preferable that the distance is 0.01 mm - 10 mm. In addition, since the electric field strength is larger and the electrolytic action is stronger when the distance between the fuse element 11 and the electrode 12 is smaller, in order to open the electric circuit more efficiently, the distance between the electrodes 12 is set to 0.01 to 1 mm. more preferably.

The fuse element 11 has a predetermined rated current value, and is fused when a current exceeding the rated current is applied. It is preferable that the fuse element 11 has as a main component any 1 type selected from aluminum, iron, nickel, tin, and lead. In addition, in this specification, a main component means 50 wt% or more of components based on the total mass of a material.

The electrodes 12A and 12B are disposed opposite to both surfaces of the central portion of the fuse element 11 . Moreover, it is preferable to arrange|position so that the electrode 12A, 12B may cover the whole surface of the center part of the fuse element 11 so that the amount of material to be etched by the fuse element 11 may become large.

Moreover, it is preferable that the electrodes 12A, 12B consist of a metal with a smaller ionization tendency than a fuse element, and have as a main component any 1 type selected from gold|metal|money, platinum, silver, copper, and palladium. Accordingly, when water enters between the fuse element 11 and the electrode 12, the fuse element 11 made of a non-metal becomes a positive electrode and is ionized (corroded), and the fuse element 11 becomes thin or , pinholes are generated, the conductor resistance of the fuse element 11 rises, and the rated current value can be reduced.

In addition, it is preferable to provide a separator between the fuse element 11 and the electrode 12 . Moreover, it is preferable that a separator consists of insulators, such as a mesh shape and a porous shape. Thereby, while suppressing the direct short circuit between the fuse element 11 and the electrode 12, the retainability of water and electrolyte solution can be ensured. In addition, the separator preferably supports an electrolyte such as NaCl. Thereby, the electrical conductivity of water or electrolyte solution can be improved, and electrolysis can be accelerated|stimulated.

Moreover, you may arrange|position an absorptive or hygroscopic insulating material between the fuse element 11 and the electrode 12. Moreover, between the fuse element 11 and the electrode 12, you may arrange|position the insulator which consists of a sol, a gel, or a solid, and you may make electroconductivity express with water. Moreover, when the electrolyte which consists of sol or a gel penetrate|invades between the fuse element 11 and the electrode 12, you may make it exhibit the electrolytic action of the fuse element 11.

Moreover, it is preferable that the fuse element 11 is connected as a positive electrode, and the electrode 12 is connected as a negative electrode. Thereby, the electrolytic reaction can be accelerated|stimulated and the rated current value of the fuse element 11 can be reduced quickly.

That is, the fuse element 10 includes a fuse element 11 connected in series as a positive electrode to a DC power supply, and a metal disposed adjacent to the fuse element 11 and having a smaller ionization tendency than the fuse element 11 , , constitutes a blocking circuit including an electrode 12 connected as a negative electrode. Moreover, it is provided with the 1st terminal and 2nd terminal for energizing the fuse element 11, and the 3rd terminal which connects the electrode 12 as a negative electrode, The 1st terminal and the 2nd terminal are serially connected to the electricity supply path|route of a positive electrode. connected, and the third terminal is connected to the negative electrode or grounded.

2 and 3 are perspective views schematically showing a fuse element before and after electrical corrosion, respectively. As shown in FIG. 2, the fuse element 11 before electric corrosion is maintaining the short shape. When water enters between the fuse element 11 and the electrode 12, as shown in FIG. 3, the fuse element 11 made of a non-metal becomes a positive electrode and is ionized (corroded), and the fuse element 11 becomes thin or , or a pinhole occurs. For this reason, the conductor resistance of the fuse element 11 rises, and the rated current value falls. Water or electrolyte solution between the fuse element 11 and the electrode 12 may evaporate due to heat generation accompanying an increase in conductor resistance. However, since the rated current value is lowered, electricity is supplied to the fuse element 11 It is magnetically shut off by the current, so it is possible to safely open the electric circuit.

Moreover, a fuse element is not limited to the structural example mentioned above, For example, a plurality of fuse elements may be arrange|positioned in parallel, and an electrode may be arrange|positioned between the fuse elements. 4 is a perspective view illustrating a configuration example of a fuse element in which a plurality of fuse elements are arranged in parallel, and FIG. 5 is a cross-sectional view illustrating a configuration example of a fuse element in which a plurality of fuse elements are arranged in parallel. As shown in FIG. 5, this fuse element has the 1st electrode 22A, the 1st separator 23A, the 1st fuse element 21A, the 2nd separator 23B, and the 2nd electrode 22B ), the third separator 23C, the second fuse element 21B, the fourth separator 23D, the third electrode 22C, the fifth separator 23E, and the third fuse element 21C ), the sixth separator 23F, and the fourth electrode 22D are stacked in this order.

First to third fuse elements 21A, 21B, 21C, first to fourth electrodes 22A, 22B, 22C, 22D, and first to sixth separators 23A, 23B, 23C, 23D, 23E, 23F ) is the same as the fuse element 11, the electrode 12, and the separator described above, respectively, and description is abbreviate|omitted here.

By arranging a plurality of fuse elements in parallel in this way, while being able to increase the rated current, it is possible to promote corrosion of the fuse element when water enters between the fuse element and the electrode.

<2. Application example of fuse element>

6 : is a block diagram which shows the application example in which the fuse element was used for the circuit in the battery pack of a lithium ion secondary battery. The fuse element 10 is attached to the battery pack 30 which has the battery stack 35 which consists of the battery cells 31-34 of a total of four lithium ion secondary batteries, for example, as shown in FIG. used

The battery pack 30 includes a battery stack 35 , a charge/discharge control circuit 40 that controls charge/discharge of the battery stack 35 , and a fuse element 10 that cuts off the output of the battery stack 35 in an abnormal state. ) and a detection circuit 36 for detecting the voltage of each battery cell 31 to 34 .

The battery stack 35 has battery cells 31 to 34 that require control for protection from overcharge and overdischarge states are connected in series, and a positive electrode terminal 30a and a negative electrode terminal 30b of the battery pack 30 are connected in series. ) is detachably connected to the charging device 45 , and a charging voltage from the charging device 45 is applied. By connecting the battery pack 30 charged by the charging device 45 with the positive electrode terminal 30a and the negative electrode terminal 30b to the electronic device operated by the battery, this electronic device can be operated.

The charge/discharge control circuit 40 includes two current control elements 41 and 42 connected in series to a current path flowing from the battery stack 35 to the charging device 45 , and A control unit 43 for controlling the operation is provided. The current control elements 41 and 42 are constituted by, for example, field effect transistors (hereinafter referred to as FETs), and control the gate voltage by the control unit 43 to control the current path of the battery stack 35 . Controls conduction and interruption. The control unit 43 operates by receiving power supply from the charging device 45 or the battery stack 35, and according to the detection result by the detection circuit 36, when the battery stack 35 is overdischarged or overcharged, The operation of the current control elements 41 and 42 is controlled to block the current path.

The fuse element 10 is equipped with the 1st terminal and 2nd terminal for energizing the fuse element 11, and the 3rd terminal which connects the electrode 12 as a negative electrode, For example, a 1st terminal and a 1st terminal The two terminals are connected on the charge/discharge current path between the battery stack 35 and the charge/discharge control circuit 40, and the third terminal is connected to the negative electrode side.

The detection circuit 36 is connected to each battery cell 31-34, detects the voltage value of each battery cell 31-34, and outputs a signal to the current control element 38 at the time of abnormality, and energizes, The charging/discharging current path is cut off by the operation of the protection element 37 .

The protection element 37 is connected on a charge/discharge current path between the battery stack 35 and the charge/discharge control circuit 40 , for example, and its operation is controlled by the current control element 38 . The protection element 37, for example, has a circuit configuration consisting of a soluble conductor and a heating element that melts the soluble conductor by energizing it through a connection point of the soluble conductor and generating heat, the soluble conductor is connected in series on the charge/discharge current path, , the heating element is connected to the current control element 38 .

The current control element 38 is a protection element ( 37) is operated to control the charging/discharging current path of the battery stack 35 to be cut off regardless of the switch operation of the current control elements 41 and 42 .

According to such an application example, water infiltrates between the fuse element 11 and the electrode 12 at the time of abnormality, such as water leakage, and the fuse element 11 is corroded. Thereby, since a rated current value falls, it self-interrupts by the energizing current to the fuse element 11, and can open an electric circuit safely.

Further, in opening the electric circuit efficiently in the case of the above abnormality, if the fuse element 11 is connected as a positive electrode and the electrode 12 is connected as a negative electrode, the connection destination of the third terminal of the fuse element 10 is particularly limited. it is not going to be For example, by setting the connection destination of the third terminal as the detection circuit 36 , it is possible to detect water entering between the fuse element 11 and the electrode 12 . Further, for example, using a primary battery, the positive electrode side may be connected to the fuse element 11 , and the negative electrode side may be connected to the third terminal. Further, the third terminal may be grounded. Moreover, in principle, since the metal with a large ionization tendency is corroded simply by immersing two metals with different ionization tendency in electrolyte solution, it is good also considering the 3rd terminal as an open state.

10: fuse element
11: fuse element
12: electrode
21A, 21B, 21C: first to third fuse elements
22A, 22B, 22C, 22D: first to fourth electrodes
23A, 23B, 23C, 23D, 23E, 23F: first to sixth separators
30: battery pack
30a: positive terminal
30b: negative terminal
31 to 34: battery cell
35: battery stack
36: detection circuit
37: protection element
38: current control element
40: charge and discharge control circuit
41, 42: current control element
43: control unit
45: charging device

Claims (8)

a fuse element on a plane;
an electrode disposed close to the fuse element and made of a metal having a lower ionization tendency than the fuse element;
The fuse element in which the said electrode is spaced apart from the said fuse element, and is arrange|positioned to oppose the said fuse element. The method of claim 1,
The fuse element has as a main component any one selected from aluminum, iron, nickel, tin, and lead;
The fuse element in which the said electrode has as a main component any 1 type selected from gold|metal|money, platinum, silver, copper, and palladium. 3. The method of claim 1 or 2,
The fuse element is made of a flat plate,
The electrode is disposed opposite to both surfaces of a central portion of the fuse element. 3. The method of claim 1 or 2,
A fuse element comprising a separator between the fuse element and the electrode. 5. The method of claim 4,
A fuse element comprising the separator supporting an electrolyte. 3. The method of claim 1 or 2,
A plurality of the fuse elements are arranged in parallel,
The fuse element in which the said electrode is arrange|positioned between the said fuse elements. 3. The method of claim 1 or 2,
The fuse element is connected as a positive electrode,
A fuse element in which the electrode is connected as a negative electrode. A planar fuse element connected in series to a DC power supply as a positive electrode;
an electrode disposed adjacent to the fuse element and made of a metal having a smaller ionization tendency than the fuse element and connected as a negative electrode;
The interrupting circuit in which the said electrode is spaced apart from the said fuse element, and is arrange|positioned to oppose the said fuse element.

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