JPH11176303A - Automatic discharge element for overheated battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a battery safety by discharging a battery in the case of an abnormal increase in a battery temperature, and controlling such a trouble that electrolyte solution is ejected. SOLUTION: This automatic discharge device 1A assembled in a battery case is provided with an operation conductive element 4 for leading a circuit at a prescribed temperature, and a discharge element 3 connected in parallel to the battery the operation conductive element 4. In the operation conductive element 4, a coil spring 45 is disposed as an elastic means for making in an initial condition a condition in which elastically energizing motion is suppressed by interposing a temperature sensor 46, and the circuit is led by moving a contact 43 actuated by the elastically energizing motion of the coil spring 45 released by fusion of the temperature sensor 46 at the time of over-heat. While, a operation-switching element is provided so as to switch over the conductive circuit to an operation conductive circuit from an initial conductive circuit at a prescribed temperature, and the initial conductive circuit is connected in series to the battery, and the operation-conductive circuit is connected in parallel to the battery through the discharge element 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic discharging device for a battery at the time of overheating in which a battery is automatically connected to a discharging device and discharged when a battery temperature rises abnormally.

[0002]

2. Description of the Related Art As electronic devices become smaller and lighter, the market for small portable devices is rapidly expanding. One example is the miniaturization of batteries with the advent of secondary batteries.

[0003] Lithium ion secondary batteries and the like, which are at the center of the present secondary batteries for small portable devices, have a high energy density. Therefore, as a safety measure for batteries and peripheral devices, current fuses are installed in battery packs. And a temperature fuse are connected to the battery circuit, and a control circuit for overcharging and overdischarging is provided.

[0004] In addition, a positive temperature (PTC) in which the impedance value rapidly rises above a predetermined temperature.
It is also generally practiced to connect a battery to a battery in series by, for example, assembling a rate coefficient element into the battery and to protect the battery against charging due to overcurrent or external short circuit.

[0005]

However, in the above-described conventional example in which the above-mentioned current fuse or the like is operated due to some abnormality, the continuity between the external circuit and the battery is simply maintained with the discharge capacity remaining in the battery. , And only the power supply was stopped.

Therefore, even after the power supply is cut off, if an abnormality remains in the battery or if the battery is at a high temperature, for example, when an internal short-circuit current flows between the electrodes of the battery and heat is generated, In some cases, the temperature of the battery further rises, and eventually, the electrolyte is ejected, which may adversely affect peripheral devices.

As described above, simply shutting off the conduction (energization) between the battery and the external circuit in the event of an abnormality cannot be said to be a necessary and sufficient safety measure, and the emergence of effective suppression means taking this into account is desired. Was.

[0008]

Therefore, the present inventor has focused on this situation and completed the present invention. Here, when the battery temperature rises abnormally, the battery is discharged, and by suppressing the problem such as the ejection of the electrolytic solution, the inventor has further improved the present invention. An object of the present invention is to provide a new automatic discharge element for a battery at the time of overheating for the purpose of improving the safety of the battery.

[0009]

To achieve the above object, the present invention is configured as follows. That is, it has a working conduction element for operating at a predetermined temperature to conduct a circuit, and is provided with a discharging element connected in parallel with the battery via the working conduction element, which is incorporated in the battery case. It is characterized by.

In the operating conduction element, there is provided an elastic means for initially setting a state in which the elasticity is suppressed by the interposition of the temperature sensing element, and the elasticity released by melting of the temperature sensing element at the time of overheating is provided. It is characterized in that the circuit is made conductive by the movement of the contact due to the elastic force of the means.

Alternatively, there is provided an operation switching element which is incorporated in the battery case and operates at a predetermined temperature to switch a conduction circuit from an initial conduction circuit to an operation conduction circuit,
The initial conduction circuit is connected in series with a battery, and the operation conduction circuit is connected in parallel with the battery via a discharge element.

Further, there is provided an operation switching element which is incorporated in the battery case and operates at a predetermined temperature to switch the conduction circuit from the initial conduction circuit to the activation conduction circuit. And the battery is connected in series with a battery via a current interrupting element that operates to shut off the battery, and the operation conducting circuit is connected in parallel with the battery via a discharging element.

In addition, in the operation switching element, the state in which the elasticity is suppressed by the interposition of the temperature sensing element is set to the initial state, and the conduction of the initial conduction circuit is established by bridging the contacts engaged with the elastic means. The contact may be formed by the elastic means released by the melting of the temperature sensing element at the time of overheating, and the contact may be moved by the elasticity of the elastic means so as to cut off the initial conducting circuit and form the conduction of the operation conducting circuit.

[0014] The suppression of the elastic activation of the operation conducting element is as follows.
By engaging the movable side of the elastic means composed of a coil spring or a leaf spring with the temperature sensing element, it is possible to hold the biasing force of the elastic means in a stored state.

[0015] Alternatively, the engagement pin attached to the contact may be engaged with the temperature sensing element to hold the biasing force of the elastic means in a stored state. Note that the operation conduction element may be a bimetal, or a switching circuit may be configured using an element whose resistance value changes in response to a temperature change, for example, a thermistor or an FET. In addition, the reaction temperature of the operating conduction element varies depending on the battery standard to be incorporated.
It is preferable to operate with.

[0016]

According to the above construction, the present invention operates as follows. That is, in the configuration of claim 1, when the ambient temperature (mainly, the temperature in the battery case) exceeds a preset temperature, the operating conductive element is activated to form a conductive circuit, and the battery is discharged. Connected to As a result, the remaining charge capacity is discharged by the discharge element, and further increase in the battery temperature is prevented.

According to the second aspect of the present invention, the temperature-sensitive body is melted by the rise in temperature, and the elastic means suppressed by the melting is released to be elastically actuated, thereby causing the conductive body to become conductive. The contacts crosslink to form a conductive circuit of the working conductive element.

According to the third aspect of the present invention, the battery is energized by the initial conduction circuit connected in series to the battery circuit, and if an overcurrent is detected, the current cutoff element operates to activate the circuit of the initial conduction circuit. Cut off. On the other hand, when an increase in the ambient temperature that is equal to or higher than the predetermined temperature is detected, the operation switching element is activated, and the conduction circuit is switched to the operation conduction circuit almost simultaneously when the initial conduction circuit is shut off, and the battery is connected to the discharge element. You. Thus, the remaining charge capacity is discharged by the discharge element, and the temperature rise is prevented, as in the operation of the first aspect.

Further, in the case of adopting the constitution of claim 4, as in claim 2, the temperature-sensitive body is melted by the temperature rise, the elastic means is elastically urged, and the conductive contact moves, The conduction circuit is switched from the initial conduction circuit to the operation conduction circuit.

In the case where a bimetal is used as the operation conduction element or the operation switching element, even if the battery is connected to the discharge element at a predetermined temperature or higher, the connection with the discharge element can be made if the temperature drops. Is separated and becomes a reversible automatic discharge element which returns to the original circuit configuration.

[0021] The term "elasticity" referred to in the present specification means:
Maintain elastic means such as coil springs, leaf springs, rubber, etc. in a state of being compressed or expanded in advance (accumulation of kinetic energy)
In addition, it refers to the elastic restoring movement caused by releasing this.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings and examples. Note that the description of directions used in the description of the present specification is in accordance with the expression form of the drawings, and is for convenience to facilitate understanding of the description, and limits the configuration of the invention. is not.

[0023]

Embodiment A Embodiment A is an example showing the invention configuration according to claim 1 in a more specific manner.

FIG. 1 is a partially cutaway perspective view showing an overall view of an automatic discharge element for a battery according to Embodiment A, and FIG. 2 is a partially cutaway front view showing a state before operation of Embodiment A. 3 is a partially cutaway front view showing a state after the operation of the embodiment A. FIG.

Automatic discharge element 1 for a battery according to Embodiment A
A is mainly composed of a case 2A, a discharge element 3 disposed in the case 2A, and an operation conducting element 4. The case 2A is formed in a cylindrical shape with both ends open, and is made of a non-conductive material made of porcelain, heat-resistant resin, or a combination thereof.

At both ends of the case 2A, conductive A external terminals 21a, 21B penetrated from the inside to the outside are respectively provided.
An external terminal 21b is provided, and is fixed with a sealing material 22 so as to seal the inside from the outside.

The discharge element 3 is obtained by winding a nichrome wire 33 as a resistor around a winding core 32 housed in a nonconductive coating cylinder 31 made of ceramic or the like, and further filling a silicate powder 34 in the surrounding space. Configuration. One end of the nichrome wire 33 is connected to the A external terminal 21a described above, and the other end is connected to an A operating contact plate 41a described later.

Next, the operation conducting element 4 is disposed in the case 2A and mainly includes a pair of A and B operation contact plates 41a and 41a.
b, a contact 43, a coil spring 45 as an elastic means, and a temperature sensing element 46.

The A and B operating contact plates 41a and 41b are constituted by a pair of two substantially semi-disc-shaped conductive materials, and these are disposed substantially horizontally (case 2A) below the discharge element 3 (on the drawing). (In the radial direction) and are spaced apart and held on the same plane. The one A-operation contact plate 41a is connected to the discharge element 3
The other B contact plate 41b is connected to the B external terminal 21b via a conductive lead wire 42 extending along the inner surface of the case 2A.

The contacts 43 are separated from each other by A, B
The operating contact plates 41a and 41b are formed in a conductive disk shape large enough to be cross-linkable, and are disposed between the operating contact plate 41 and the inner flange portion 23 in the case 2A disposed at a fixed distance. .

The contact 43 is provided with a bar-shaped locking pin 44 extending downward through a substantially central portion thereof, and the lower surface of the contact 43 is provided with the locking pin 44.
A coil spring 45 mounted around the abutment is disposed in contact with the coil spring 45.

The temperature sensing element 46 is made of a low melting point alloy that melts at a temperature close to the softening point temperature of the battery separator, and is filled in a filling cylinder 47 arranged and fixed at a predetermined distance from the inner flange 23. . Upper end opening 47a of filling cylinder 47
Is reduced in diameter to prevent the temperature sensing element 46 from coming out.

The initial state of the operation conducting element 4 having such a configuration (a state in which the elasticity is suppressed) is set by the contact 4
The coil spring 45 is deflected until the coil spring 3 contacts and engages with the inner flange portion 23, and in this state, the engagement pin 44 is embedded and fixed in the cured thermosensitive body 46.

The distance between the upper end opening 47a of the filling cylinder 47 and the contact plate 41 is set shorter than the free length of the coil spring 45. Automatic discharge element 1A for such a battery
Are disposed in the vicinity of the battery 51 in the battery pack 5 of the cylindrical battery, and the A external terminal 21a and the B external terminal 21b
To the positive lead plate 52a and the negative lead plate 5 on the battery 6 side.
2b (FIG. 4), and the other side of the positive lead plate 52a and the negative lead plate 52b is connected to an external circuit (not shown).

[0035]

The operation of the embodiment A constructed as described above operates as follows. When the battery temperature reaches the melting temperature (operating temperature), the temperature sensing element 46 melts, whereby the holding of the locking pin 44 by the temperature sensing element 46 is released, and the suppression of the coil spring 45 is released (arrow). a), due to the restoring force of the bent coil spring 45, the contact 43 resiliently urges upward and comes into contact with the A-operation contact plate 41a and the B-operation contact plate 41b (arrow b). At this time, the coil spring 45 still has a restoring force, and the contacts are pressed against the A contact plate 41a and the B contact plate 41b, so that the conduction circuit is maintained (FIG. 3).

As a result, the discharge element 3 and the battery 51 are connected in parallel, and discharge is started. By the way, if the melting temperature of the temperature sensing element is too high, the battery temperature may increase and the electrolyte may be ejected before the temperature sensing element operates and the battery is discharged, and On the other hand, if the temperature is higher than the battery separator softening point, the porosity of the separator decreases, making it difficult to discharge, and furthermore, there is an inconvenience that an internal short circuit occurs in the battery due to melting of the separator.

Therefore, the melting temperature of the thermosensitive element is desirably set to a temperature lower than the softening point temperature of the battery separator, preferably 140 ° C. or lower, and more preferably 100 ° C. in consideration of the operating environment of the battery-mounted device. It is desirable to set the temperature to at least ℃.

On the other hand, if the resistance value of the resistor is too low, the discharge current when the temperature sensing element operates becomes large, causing the destruction of the battery automatic discharge element or abnormal heat generation due to the internal resistance of the battery. May cause.

Conversely, if the resistance value is too high, the discharge current becomes small, so that abnormal heat generation or the like due to the internal resistance of the battery is suppressed. Since the temperature rises to cause a state in which the battery becomes unstable, in the case of a single battery, it is considered that 0.1 to 0.4 Ω, which is about the internal resistance value of the battery, is desirable. However, if the internal resistance of the battery or the operating temperature of the thermosensitive element is different, the optimum resistance value naturally differs in consideration of this.

When a battery pack is used, it is necessary to consider the number of batteries, the electrode area, the electrolyte used, the internal resistance of the battery, the location of the battery, the use environment, and the like. The temperature and the resistance are not limited to the present embodiment.

When the automatic discharge element is activated,
The battery is short-circuited via the resistor and completely discharged to 0V
Becomes Charging this with a constant-current / constant-voltage charger is the same as charging a battery with a short-circuited voltage of 0 V, and it is considered that there is no particular problem. Is done).

[0042]

Modification of Embodiment A The above-described embodiment A may be modified as follows. The battery automatic discharge element 1A can be arranged at an appropriate place.
Since the shape is not limited to a cylindrical shape, it may be, for example, a polygonal column shape or a disk shape. Working contact plate 4
The one shape is not limited to a substantially semicircular shape, and may be a flat plate of an appropriate shape arranged at a predetermined distance.

In the embodiment A, the A external terminal 21a,
The B external terminal 21b is connected to the positive lead plate 52a,
Although it is welded to the negative electrode lead plate 52b, the polarity is not limited. Further, the coil spring 45 is used as the elastic means, but is not limited thereto.
It may be replaced with another elastic element, such as a leaf spring, which enables elasticity of the spring.

Further, by replacing the operation conduction element 4 with a bimetal element, the battery is discharged by conducting connection when the ambient temperature reaches a predetermined temperature or higher, and conduction is performed when the ambient temperature drops. A reversible mechanism may be used in which the connection is released and the battery can be charged again for charging.

Furthermore, the operating conduction element 4 is connected to an element whose resistance changes in response to a temperature change, for example, a thermistor or F
You may make it comprise a switching circuit using ET.

[0046]

Embodiment B Next, Embodiment B is an example showing the invention configuration according to claims 3 and 4 more specifically.

FIG. 5 is a partially cutaway perspective view showing the general appearance of the battery automatic discharge element of the embodiment B, and FIG. 6 is a partially cutaway front view showing the state before the operation of the embodiment B. 7 is a partially cutaway front view showing a state after the operation of the embodiment B. FIG.

In the embodiment B, in brief, an initial conducting circuit is formed in the initial state of the working conducting element 4 which is a main component of the embodiment A, and the conducting circuit is connected to the conducting circuit of the working conducting circuit from this circuit. And a current interrupting element for interrupting an external circuit (charging circuit) when an overcurrent occurs, is added to the initial conducting circuit. Therefore, in the description of the discharge element and the operation switching element, the same parts as those in the above-described embodiment A are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

The case 2B of the battery automatic discharge element 1B of the embodiment B is formed in the same manner as in the embodiment A, and similarly has the A external terminal 21a and the B external terminal 21b at both ends.
Is arranged.

The discharge element is the discharge element 3 of the embodiment A.
This is the same configuration as. The operation switching element 6 is obtained by adding an initial conduction circuit to the operation conduction element 4, and is a component of the operation conduction element 4, that is, a pair of A and B operation contact plates 41a,
The arrangement of the contact 41b, the contact 43, the coil spring 45, and the temperature sensing element 46 is the same as in the embodiment A. However, of the pair of A and B operation contact plates 41a and 41b,
The other B contact plate 41b has a configuration in which it is connected to a discharge terminal 21c penetratingly installed outside the case.

The initial conduction circuit includes a pair of A and B made of two substantially semi-disk-shaped conductive materials on the upper surface of the inner flange portion 23.
The initial contact plates 61a and 61b are spaced apart from each other, and the contacts 43 are cross-linked to the initial contact plates 61a and 61b. The A initial contact plate 61a is connected to the A external terminal 21a via an upper lead wire 62 extending upward along the inner surface of the case 2B, while the B initial contact plate 61a is similarly extended downward. It is connected via a lead wire 63 to one end of a fuse element 7 as a current interrupting element. And
The other end of the fuse element 7 is connected to the B external terminal 21b.

As a result, the initial conduction circuit connected to the A external terminal 21a, the upper lead wire 62, the pair of A and B initial contact plates 61a and 61b, the contact 43, the lower lead wire 63, the fuse element 7, and the B external terminal 21b. Are formed.

On the other hand, the operation conduction circuit is the A external terminal 21
a, discharge element 3, a pair of A, B operating contact plates 41a, 41
b, the contact 43, and the discharge terminal 21c.

The initial state of the operation switching element 6 having such a configuration (a state in which the elasticity is suppressed) is set by the contact 4
3, the coil spring 45 is bent until it comes into contact with the pair of A and B initial contact plates 61a and 61b, and in this state, the engaging pin 44 is embedded and fixed in the cured thermosensitive body 46. .

In the battery automatic discharge element 1B, the A external terminal 21a, the discharge terminal 21c, and the B external terminal 21b are respectively connected to the positive lead plate 52a, the negative lead plate 52b, and the external circuit lead plate 52c on the battery 51 side. The external circuit side lead plate 52 is connected to the external circuit side (FIG. 8).
c, connected to an external circuit (not shown) through the negative lead plate 52b.

[0056]

Operation of Embodiment B The above-described Embodiment B operates as follows. In the normal energized state, the above-described initial conduction circuit is formed, so that charging and discharging (energization) are performed between the external circuit and the battery 51 in the battery pack 5.

Here, when the peripheral temperature of the battery automatic discharge element 1B rises and reaches a predetermined temperature, the temperature sensing element 46 melts, thereby holding the locking pin 44 by the temperature sensing element 46. Is released, the restrained state of the coil spring 45 is released, and the contact 43 is repelled upward by the elastic force of the coil spring 45 (arrow c).

By the movement of the contact 43, the initial conduction circuit via the A initial connection plate 61a and the B initial connection plate 61b is cut off, and the conduction between the battery 51 and the external circuit is cut off. On the other hand, at about the same time, the contacts 43 are pressed against the A-operation contact plate 41a and the B-operation contact plate 41b (arrow d), and a conduction circuit of the operation conduction circuit is formed (FIG. 7).

As a result, the discharge element 3 and the battery 51 are connected in parallel, and discharge is started. If an overcurrent flows more than expected in the battery automatic discharge element 1B, the fuse element 7 is turned on regardless of the operation of the operation switching element 6.
Operates independently to cut off the connection to the external circuit, but even in this case, there is no problem in switching the conduction circuit from the initial conduction circuit to the operation conduction circuit.

[0060]

Modification of Embodiment B The above-described embodiment B may be modified as follows in order to achieve the object of the present invention.

The shape of the case 2B is not limited as in the case of the embodiment A, and the polarity of the battery connected to the A external terminal 21a and the discharging terminal 21c is not limited. In the embodiment B, the arrangement of the fuse elements 7 is
Although it is between the B external terminal 21b and the B initial connection plate 61b, it may be between the A external terminal 21a and the A initial connection plate 61a, or a configuration in which the fuse element 7 is omitted. Is also possible.

Further, the operation switching element 6 of the embodiment B can be replaced with a bimetal element. In other words, the reversibility that the bimetal element is moved between the initial connection plate 61 and the working contact plate 41 at a predetermined temperature to repeat the energization and discharge of the battery in response to the ambient temperature is repeated. It may be configured.

If one of the external terminals 21 of the embodiment B is insulated (not connected to a circuit), it can be used as the operation conducting element 4 of the embodiment A.

[0064]

[Embodiment C] Next, Embodiment B is an example showing the present invention according to claims 3 and 4 in more concrete terms.

FIG. 9 is a partially cutaway perspective view showing the entirety of the battery automatic discharge element of the embodiment C, and FIG. 10 is a partially cutaway front view of the battery automatic discharge element of the embodiment C. FIG. 11 shows an automatic discharging element for a battery according to the embodiment C.
FIG. 3 is an exploded perspective view when the battery is incorporated in a battery as a secondary battery protection element.

In the embodiment C, a disk-shaped thick disk is used in consideration of the incorporation into a battery (particularly, a secondary battery) while keeping the basic configuration of the embodiment B. Therefore, in the description of the discharge element, the operation switching element, and the fuse element, the same parts as those in the above-described embodiments A and B are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

The case 2C is made of a non-conductive material, and its outer shape is formed in a thick disk shape. In the present embodiment C, for example, it is formed of a ceramic material in a disk shape having a diameter of 15 mm and a thickness of several mm. In the case 2C, a rectangular through opening 24 is formed substantially at the center thereof.
An upper and left and right U-shaped (in FIG. 10) space 25 is formed so as to surround the through opening 24.

A and B disk-shaped terminals 8 made of a conductive material (for example, nickel material) are provided on both opposing bottom surfaces of the case 2C.
a, 8b are arranged so as to sandwich the case 2C via the non-conductive layer 81 laid on the entire surface or the required surface. The disc-shaped terminal 8 is provided with an opening 82 at a position corresponding to the through-opening 24, and is connected to the inside, so that the disc-shaped terminal 8 and the non-conductive layer 8 are formed.
1 is provided with a through-hole 83 penetrating through 1 and a cut-out portion 84 in which only the portion of the disc-shaped terminal 8 larger than this is cut out and deleted.

In the space 25 of the case 2C, the fuse element 7 is disposed on the right side (in the drawing), the operation switching element 6 is disposed on the left side, and the discharge element 3 is disposed on the upper side.

The fuse element 7 has an A connection plate 26 at one end.
A on the back side (back side in FIG. 10) of case 2C through
The right lead wire 64 is connected to the disc-shaped terminal 8a.
Is connected to one end of the discharge element 3 through the other end, and is connected to the A-operation contact plate 41a from the other end through the left lead wire 66. On the other hand, the other end of the fuse element 7 is connected to the A initial contact plate 61a via the upper lead wire 65.

The B initial contact plate 61b, which is bridged and conducted by the A initial contact plate 61a and the contact 43, is integrated with the B external contact plate 26b, and the B initial contact plate 61b on the front side (front side in FIG. 10) of the case 2C via this. It is connected to the disk-shaped terminal 8b.

Here, each of the disk-shaped terminals 8a, 8b and A, B
Each of the connection plates 26a and 26b is electrically connected to each other. The connection plate 26 is extended outward by a predetermined length through the disc-shaped terminal 8 and the through hole 83 of the non-conductive layer 81, and is made substantially coincident with the extended portion. The notch 84 is bent and welded to the disk terminal 8. At this time, the thickness of the extended portion of the connection plate 26 and the thickness of the disc-shaped terminal 8 are made substantially the same,
I try to finish it flush.

A working contact plate 41a and B working contact plate 41
b, the contact 43, the locking pin 44, the coil spring 45, and the temperature sensing element 46 are configured in the same manner as in the above-described embodiments A and B.

The working contact plate 41a connected from the discharge element 3 via the left lead wire 66 and the working contact plate 4 bridged and connected by the contact 43 after the resilient operation.
1b is connected to the discharge terminal 21c as in the embodiment B, and is arranged to extend inside the through hole 24.

[0075]

Operation of Embodiment C The battery automatic discharge element 1 having the above-mentioned structure.
C is a top cover 9 of the battery 51 with the B disk-shaped terminal 8b facing upward (external circuit side) as shown in FIG.
1 and the safety valve 92, which are incorporated in the battery by being sealed.

That is, the A disk-shaped terminal 8a is on the battery side, and the B disk-shaped terminal 8b is connected to an external circuit (not shown) via the top cover 91. The discharge terminal 21c is connected to the battery can 9 via a lead wire or the like (indicated by a dashed line in the drawing) which is electrically insulated from the top cover 91 and drawn out from a lead-out port 93 provided in the top cover 91.
4 is connected.

In the normal energized state, the A disk-shaped terminal 8a and the B disk-shaped terminal 8b are electrically connected via the contact 43 bridged to the A initial contact plate 61a and the B initial contact plate 61b, respectively. Therefore, the external circuit and the battery 51
And charging and discharging (energization) are performed.

Here, when the peripheral temperature of the battery automatic discharge element 1C rises and reaches a predetermined temperature, the temperature sensing element 46 melts,
As a result, the holding of the locking pin 44 is released, the suppressed coil spring 45 is resiliently urged, and the contact 43 is flipped upward (arrow e). Thus, A
When the connection between the initial contact plate 61a and the B initial contact plate 61b is released, almost at the same time, the contact 43 is pressed against the A operating contact plate 41a and the B operating contact plate 41b,
The conduction circuit will be switched.

As a result, a conduction circuit is formed between the A disk-shaped terminal 8a and the discharging terminal 21c via the discharging element 3, so that the battery 6 connected in parallel with the battery automatic discharging element 1C is connected. The residual amount of electricity will be discharged.

As in the case of Embodiment B, when an overcurrent flows more than expected in the battery automatic discharge element 1C,
The fuse element 7 operates independently irrespective of the operation of the operation switching element 6, and the connection with the external circuit is cut off.

Further, since the inner side surfaces of the respective disc-shaped terminals 8a and 8b which come into contact with the case 2C are covered with the non-conductive layer 81, the contacts 43 after the repulsive operation come into contact in the space 25. Problems such as re-conduction between the disc-shaped terminals 8a and 8b do not occur.

Further, the through-hole 2 provided in the case 2C
4 shows the battery 51 when the internal pressure of the battery rises and the safety valve is opened.
Plays the role of vent hole from inside.

[0083]

Modification of Embodiment C In the embodiment C, the case 2C is provided with the rectangular through-hole 24, but the shape of the through-hole is not limited to this.

The arrangement of each component in the case 2C is not limited to the present embodiment, and the shape of the case may be appropriately changed in the case of adopting a prismatic battery.

Further, when the battery automatic discharge element 1C of the embodiment C is provided in a battery having no gas vent, or when it is provided on the negative electrode side (battery can bottom) of the battery, the through hole is provided. May be omitted.

[0086]

Other Embodiments In the embodiments A, B and C, the contacts after the resilient operation of the actuation conducting element are pressed upward (in the drawing) by a spring having a residual elastic restoring force. The contact plates are electrically connected, but in addition, by adding a coil spring that applies an upward tensile force, or by arranging a permanent magnet above the contact and the contact,
It is also possible to make sure that the contact connection state of the contact after the resilient biasing action is maintained by a pulling force or a magnetic attraction force, so that the connection between the contact plates is reliably connected (not shown).

Further, since the contact and the connection plate are merely connected to each other, conduction is ensured. Therefore, by fusing them together with the same low melting point alloy as the temperature sensing element, conduction in a normal energized state is achieved. More certainty is possible.

In this case, since the low-melting point alloy for fusing between the contact and the connection plate is melted at a predetermined temperature together with the temperature-sensitive body, there is no hindrance to the elasticity.

[0089]

EXAMPLE An automatic discharge element for a battery having the structure of Embodiment A was prepared by using five types of temperature sensing elements having the operating temperatures shown in Table 1 and setting the resistance value of the resistor to 0.2Ω.

Next, a self-discharge element for this battery is connected in parallel with a commercially available 18650 type lithium ion battery, and a temperature fuse which operates in series with this at the same temperature as the operating temperature of the thermosensitive element of the automatic discharge element for battery. , A light emitting diode for monitoring the operation status of the battery automatic discharge device was attached to form a test circuit. At this time, the lithium ion battery and the battery automatic discharge device were sufficiently separated so as not to receive heat interference from each other to form a circuit, and the lithium ion battery was fully charged.

Subsequently, the measuring end of the temperature measuring device was attached to the lithium ion battery and the battery automatic discharge device, and the temperature measuring device was placed in a constant temperature bath set at 5 ° C. higher than the operating temperature of the temperature sensing element.
The temperature of the thermostat is gradually raised, and the operation of the thermosensor is checked by turning off the light emitting diode set outside the thermostat, and automatic discharge for the lithium ion battery and the battery is performed at the time of operation of the thermosensor and 5 minutes after the operation. The surface temperature of the device was measured.

The test was performed using three automatic discharging elements for batteries at each operating temperature, and the measured values were averaged to obtain a result. After the test, the battery was disassembled to check whether the safety valve was activated. The results are shown in Table 1.

[0093]

[Table 1] From Table 1, it can be seen that in the lithium ion battery using the battery automatic discharge elements E and F, the safety valve was activated, and in the battery using the element E, almost no electrolytic solution was blown out. Erupted.

After the test, the internal resistance of the lithium ion battery was measured before the battery was disassembled. As a result, although there was almost no change in the battery automatic discharge devices A and B, the devices C and D increased slightly, E and F were almost 0.

After disassembly of the battery after the test, the devices E and F
In the battery using, the separator is melting, and locally,
Particularly, in the battery using the element E, the internal short circuit was remarkably caused.

For comparison, a 18650 type lithium ion battery in a fully charged state and a completely discharged state was prepared, and only the battery was put into a thermostat set at 165 ° C., and the surface temperature of the battery was measured. The battery in the state did not have an abnormal rise in temperature and did not operate the safety valve, but the battery in the fully charged state operated the safety valve to squirt the electrolyte and the surface temperature reached a maximum of 254 ° C.

From the results of the above comparative tests, it was found that the battery in the discharged state is safer even at high temperature than the battery in the fully charged state, suggesting the effectiveness of the automatic discharge element of the present invention.

[0098]

[Effect] Since the present invention is configured as described above,
The following effects are obtained. That is, the operation conducting element is activated due to the melting of the temperature sensing element, and the contact connected thereto is flipped out, so that the battery can be reliably connected to the discharge element.

When a current cutoff element is connected,
The operating conduction element is activated due to the melting of the temperature sensing element, the contact connected to this element is popped out, and the battery is securely connected to the discharging element. The conduction with the circuit can be cut off.

Further, when the current cutoff element is made of a bimetal, even after the battery is connected to the discharge circuit at a predetermined temperature or higher, the connection with the discharge circuit can be cut off when the temperature drops, so that the reset type is used. By functioning as a discharge circuit,
The battery can be made re-energizable.

Therefore, the battery is connected to the discharge element to discharge the battery, or the battery is disconnected from the external circuit, instead of disconnecting the battery from the external circuit (energization) at the time of abnormality as in the prior art. In addition, since the battery is connected to the discharge element for discharging, it is possible to prevent adverse effects on peripheral devices due to gas ejection from the battery.

That is, in the battery using the battery automatic discharge element, the battery is forcibly discharged by the operation of the temperature sensing element, further suppressing the heat generation of the battery and reducing the internal short-circuit current. Therefore, it is considered that safety can be improved.

Therefore, in recent years, the range of application to various electric appliances in which the size of the electric circuit board is remarkably reduced is remarkably widened.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an overall view of an automatic discharge element for a battery according to Embodiment A.

FIG. 2 is a partially cutaway front view showing a state before an elastic force of Embodiment A.

FIG. 3 is a partially cutaway front view showing a state after an elastic force of Embodiment A.

FIG. 4 is a schematic perspective view showing a use state of the battery automatic discharge element of Embodiment A.

FIG. 5 is a partially cutaway perspective view showing an overall view of an automatic discharge element for a battery according to Embodiment B.

FIG. 6 is a partially cutaway front view showing a state before an elastic force of Embodiment B.

FIG. 7 is a partially cutaway front view showing a state after the elastic force of Embodiment B.

FIG. 8 is a schematic perspective view showing a use state of the battery automatic discharge element of Embodiment B.

FIG. 9 is a partially cutaway perspective view showing the entire battery automatic discharge element of Embodiment C.

FIG. 10 is a partially cutaway front view of the battery automatic discharge element of Embodiment C.

FIG. 11 is an exploded perspective view when the battery automatic discharge element of Embodiment C is incorporated in a battery as a secondary battery protection element.

[Explanation of symbols]

 1A, 1B, 1C: Automatic discharge element for battery 2A, 2B, 2C: Case 21: External terminal 21a: A external terminal 21b: B external terminal 21c: Discharge terminal 22 ... Sealant 23 ... Inner flange part 24 ... Through port 25 ... Space 26a ... A connection plate 26b ... B connection plate 3 ... Discharge element 31 ... Coating cylinder 32 ... winding core 33 ... nichrome wire 34 ... silicate powder 4 ... working conduction element 41 a ... A working contact plate 41 b ... B working contact plate 42 ... lead wire 43 ... Contact 44 ... Locking pin 45 ... Coil spring 46 ... Temperature sensing element 47 ... Filling cylinder 47a ... Top open edge 5 ... Battery pack 51 ... Battery 52a ... Positive electrode side lead plate 52b ... Negative electrode side lead plate 52c ... external circuit side lead plate 6 ... operation switching element 61a ... A initial contact plate 61b ... B initial contact plate 62 ... upper lead wire 63 ... lower lead wire 64 ...・ Right lead wire 65 ・ ・ ・ Top lead wire 66 ・ ・ ・ Left lead wire 7 ・ ・ ・ Fuse element 8 ・ ・ ・ Disc shaped terminal 8a ・ ・ ・ A disc shaped terminal 8b ・ ・ ・ B disc shaped terminal 81 ・ ・-Non-conductive layer 82-Opening 83-Through hole 84-Notch 91-Top cover 92-Safety valve 93-Draw-out port 94-Battery can 95- gasket

Claims (9)

[Claims] 1. A discharging element which is incorporated in a battery case and has an operation conducting element which operates at a predetermined temperature to conduct a circuit, and which is connected in parallel with a battery via the operation conducting element. An automatic discharging element for a battery at the time of overheating, comprising: 2. An operation conducting element, comprising: an elastic means for initializing a state in which elasticity is suppressed by the interposition of a temperature sensing element, wherein the elasticity released by melting of the temperature sensing element at the time of overheating is provided. 2. The automatic discharge element for a battery at the time of overheating according to claim 1, wherein the circuit is made conductive by the movement of the contact due to the elastic force of the means. 3. An operation switching element that is incorporated in a battery case and that operates at a predetermined temperature to switch a conduction circuit from an initial conduction circuit to an operation conduction circuit, wherein the initial conduction circuit includes a battery and An automatic discharge element for a battery at the time of overheating, wherein the automatic conduction element is connected in series and the operation conduction circuit is connected in parallel with the battery via a discharge element. 4. An operation switching element which is incorporated in the battery case and operates at a predetermined temperature to switch a conduction circuit from an initial conduction circuit to an operation conduction circuit, wherein the initial conduction circuit has an overcurrent An automatic discharge element for a battery at the time of overheating, wherein the operation conduction circuit is connected in parallel with the battery via a discharge element, while being connected in series with the battery via a current interruption element which operates to shut off the battery. 5. An operation switching element, wherein a conduction of an initial conduction circuit is formed by bridging a contact engaged with an elastic means for initially setting a state in which elasticity is suppressed by the interposition of a temperature sensing element. The structure is such that the initial conducting circuit is cut off and conduction of the operating conducting circuit is formed by the movement of the contact caused by the elasticity of the elastic means released by the melting of the temperature sensing element at the time of overheating. The automatic discharge element for a battery at the time of overheating according to claim 3 or 4. 6. The restrained state is maintained by suppressing the elastic movement by engaging a movable side of an elastic means comprising a coil spring or a leaf spring with a temperature sensing element. The automatic discharge element for a battery at the time of overheating according to claim 2 or 5. 7. The automatic discharge element for a battery at the time of overheating according to claim 6, wherein a locking pin attached to the contact is embedded and fixed in the temperature sensitive body when engaging with the temperature sensitive body. 8. The automatic discharge element for a battery at the time of overheating according to claim 1, wherein the operation conduction element or the operation switching element is bimetal. 9. The battery for overheating according to claim 1, wherein the operating temperature of the operation conducting element or the operation switching element is 100 ° C. to 140 ° C. Automatic discharge element.