JP2671171B2 - Battery with over-discharge overheat prevention device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having a device for preventing an accident due to overheating and overheating. 2. Description of the Related Art In a device using a battery, the power source may be shut down for some reason. In that case, a large current flows from the battery, which causes the battery to overheat, which may damage the plastic parts around the battery or destroy the components of the electric circuit. There is also a risk that the battery itself may leak or even explode. Conventionally, it is known to use a temperature fuse to prevent such an accident, and its configuration is shown in FIG. In FIG. 1, 51 is a battery, two of which are arranged side by side, and a connecting piece 60 is welded to the anode of one battery and the cathode of the other battery to connect the two batteries in series. The electrodes 61, 6 which are not connected to each other are connected to each other.
2 are welded to each other, and the connector 5 is attached to each contact piece 61, 62.
Lead wires 63, 58 are connected via 6, 57. One lead wire 58 is connected to a circuit component (not shown), while the other lead wire 63 is connected to the connector 54.
Is connected to the temperature fuse 53 through, and the lead wire 59 extends from the temperature fuse 53 through the connector 55,
Its tip is connected to a circuit component (not shown).
The temperature fuse 53 is attached to the heat conduction plate 52 that transfers the heat generated in the battery 51 to the temperature fuse 53,
This heat conduction plate 52 is wound around one battery 51. In this configuration example, when a battery is overheated due to a short or the like, this heat is transmitted to the temperature fuse 53 through the heat conduction plate 52, and when the temperature exceeds a predetermined temperature, the temperature fuse 53 is cut off and a circuit is formed. Since it is cut off, it is possible to prevent further overheating. By the way, in an apparatus using such a temperature fuse, once the temperature fuse is overheated and cut, the temperature fuse cannot be reused unless it is replaced. Therefore, the temperature fuse is replaced. It is necessary to make it possible to connect it with a connector as shown in FIG. 1 or to hold it detachably by a heat conduction plate as shown in FIG. 1, which increases the number of parts and makes the assembly troublesome. . In addition, the cutoff temperature of the temperature fuse is generally as high as 95 ° C or higher, and it cannot be cut off unless the member (for example, battery) with which the temperature fuse is in contact has a high temperature. It was insufficient to prevent it. As a countermeasure against this, there has been proposed a structure in which a conductive polymer whose resistance value increases with temperature rise is connected in series to a battery (as one example, JP-A-55-10598).
No. 0). With this configuration, the conductive polymer exhibits a low resistance value to cause the battery to operate normally when there is no abnormal heat generation in the normal operation of the battery, and when the battery is overheated due to overcurrent, the conductive polymer is It shows a high resistance value and shuts off the current to prevent accidents due to overheating of the battery, and when the cause of battery heat generation is removed, the resistance value decreases due to the temperature drop of the conductive polymer, and normal operation is restored. To do. However, even in the configuration using the above-mentioned conductive polymer, when the heat applied to the conductive polymer or the heat generated in the conductive polymer itself is transferred to and dissipated to the battery exterior having a large heat capacity or the outside of the battery, it becomes conductive. The temperature rise of the water-soluble polymer is suppressed, and the current cannot be interrupted quickly.
In addition, even if the cause of heat generation in the battery is removed, heat is transferred from the exterior of the battery, which has a large heat capacity, and the temperature drop of the conductive polymer slows down, so it takes time to restore the normal state. I got it. Furthermore, a cylindrical battery
In some cases, one pole (usually the cathode) is also used as the battery exterior.
Therefore, do not handle the battery by placing it on a metal plate, etc.
There is a risk that the electrodes may short-circuit due to carelessness, etc.
Was inconvenient. An object of the present invention is to solve the above problems. Means for Solving the Problems [0008] The present invention is to solve the above-described problems, and is to expose an anode body and a cathode body for generating an electric current and to the outside by being connected to the anode body and the cathode body. A battery having an anode terminal and a cathode terminal for taking out the current to the outside, and an exterior member in which one of the anode terminal and the cathode terminal is electrically connected while accommodating the anode body and the cathode body, The exterior member is insulated
A conductive polymer , whose outer surface is covered with a member, and whose resistance value increases according to temperature rise, is interposed between the electrode-side polar body on the side not electrically connected to the exterior member and the terminal. It is characterized by being worn. [0009] When an overcurrent flows due to a situation such as a short circuit of the battery electrodes, the conductive polymer rapidly generates heat due to its characteristics, but the conductive polymer is electrically charged to the exterior member of the battery having a large heat capacity. Since it is interposed between the electrode body on the side not electrically connected and the terminal, the generated heat is not transferred to the exterior member of the battery having a large heat capacity through the terminal, and the temperature of the conductive polymer itself is Since it rises rapidly and the electric resistance rises rapidly, overcurrent can be interrupted or the current can be greatly limited in a short time. Also, when the cause of fever disappears,
Since the conductive polymer is interposed between the electrode body and the terminal on the side that is not electrically connected to the exterior member of the battery with a large heat capacity, the temperature of the conductive polymer drops rapidly in a short time, The current is cut off or the restriction is released. Furthermore, in addition to the structure for blocking the overcurrent due to the conductive polymer or for greatly limiting the current, a structure in which the outer surface of the battery exterior member is covered with an insulating member so that the short circuit of the electrode does not easily occur is added. The safety structure can further reduce the probability of an accident due to a short circuit of the electrodes. Embodiments of the present invention will be described below with reference to the drawings. In recent years, a conductive polymer has been developed which has a characteristic that when the temperature rises, the electric resistance value increases as the temperature rises. This conductive polymer has an electric resistance value of about 0.04 Ω at room temperature, and has a resistance of about 1/250 of that of a general thermistor, which is extremely good in conductivity. However, the resistance value significantly increases as the temperature rises. Increase. FIG. 2 shows the resistance value with respect to temperature of this conductive polymer. The resistance value is from 10 ⁻¹ Ω to 10 ⁶ to 1
It has been shown that the variation is extremely wide up to about 0 ⁷ Ω. FIG. 3 shows a heat radiation curve and a heat generation curve of the conductive polymer. P ₁ is a heat generation curve when a normal current is flowing, and P ₂ is a heat radiation curve when the ambient temperature is T ° C. is there. The heat generation curve P ₁ and the heat radiation curve P ₂ intersect at points A, B, and C, and of these points, the heat radiation curve P _{2 at} points A and C rises more than the heat generation curve P ₁ due to the rise in temperature. The point is the equilibrium point of temperature.
Point A is near room temperature and point C is near high temperature, and normally equilibrium at point A. At this time, the electric resistance value of the conductive polymer is about 0.04Ω, and the current flows normally. When an overcurrent flows for some reason, the heat generation curve changes so that the entire body moves upward from P ₁ .
One state at this time is shown by P ₃ in the figure. With such heating curve moves upward, it is not the heating curve P ₃ at about room temperature equilibrium point of the heat dissipation curve P _2, the heating value is the heat radiation amount exceeded connexion, a relatively low temperature other components such as a battery Over time, the temperature of the conductive polymer rises. When the temperature rises, the resistance value of the conductive polymer increases as shown in FIG. 2, so that it becomes difficult for current to flow, and conversely the amount of heat generation decreases.
As a result, the heat generation curve P ₃ and the heat radiation curve P ₂ intersect at a point D near the high temperature, and the temperature is stabilized with this point as an equilibrium point. After that, the conductive polymer shows an extremely high resistance value at the equilibrium point and blocks the flow of current, so that the battery and other parts do not overheat further at a relatively low temperature, and the parts are destroyed. To be prevented. After that, when the cause of the overcurrent is removed and the ambient temperature decreases, the exothermic curve returns to the normal state, the conductive polymer reaches the normal equilibrium point A, and it can be used again in the normal state. become. By using the conductive polymer as described above, it is possible to prevent the plastic parts and circuit parts from being damaged due to the temperature rise due to the overcurrent, and to eliminate the cause of the overcurrent. Therefore, it can be used normally again. FIG. 4 shows an example of the shape of a conductive polymer member to be mounted on a battery. The conductive polymer is thinly formed and sandwiched between a pair of conductive plates 5 to be integrated so that the conductive polymer member 2 is formed. Is formed. FIG. 5 is a sectional view showing the structure of the battery of the first embodiment of the present invention. The structure is characterized in that the conductive polymer 4 is interposed between the electrode body on the cathode side of the battery and the terminal. There is a point. In the figure, 10 is an anode material formed under high pressure, and 11 is a cathode material in which high-purity zinc powder is dispersed. The anode material 10 and the cathode material 11 are separated by the separator 13
In isolation. Reference numeral 15 is a sealing packing, which is formed in an umbrella shape, and the peripheral portion seals the lower end of the battery exterior.
Further, a current collector rod 12 which penetrates the sealing body packing 15 and is inserted into the cathode material 11 is arranged in the central portion thereof. A conductive polymer member 2 constituted by sandwiching a conductive polymer 4 between two conductive plates 5 is attached to the outside of the sealing body packing 15, and the collector rod 12 and the conductive polymer member 2 are electrically connected to each other. Electrically connected, the conductive plate 5 of the conductive polymer member 2 constitutes the cathode terminal 6 of the battery. Further, the sealing body packing 15 is provided with a liquid leakage preventing cap 14 for eliminating a gap between the sealing body packing 15 and the collector rod 12 to prevent liquid leakage. Reference numeral 19 is an anode terminal, and as shown in FIG.
It is electrically connected to the upper end surface of the anode inner can 16 accommodating 0. The outer casing of the battery is an inner anode can 16 containing the anode material 10 from the inside and an outer anode can 1 outside the inner anode can 16.
7, a label 20 on which the name of the surface is printed, and an exterior material 21 made of a heat-shrinkable vinyl chloride pipe. After the contents are stored in the anode inner can 16 and the anode outer can 17, the sealing packing 15 is tightened by drawing to seal the contents. In addition, 18 is an insulating plate. In the battery of the first embodiment having the above-mentioned structure, the anode terminal 19 is the inner can 16 of the anode which constitutes the exterior of the battery.
And the cathode terminal 6 is not electrically connected to the exterior of the battery.
Of the conductive plate 5, and the conductive polymer 4 is interposed between the collector rod 12, that is, the cathode body and the cathode terminal 6. It is well known that when two objects are electrically connected to each other, they are also thermally connected and heat is transferred. Next, the operation will be described. When an overcurrent flows due to a situation such as a short circuit in the battery electrode, the heat generated inside the battery is transferred to the conductive polymer and also rapidly generates due to the characteristics of the conductive polymer itself. At this time, since the cathode terminal 6 is not electrically (ie, thermally) connected to the exterior (the anode inner can 16 and the anode outer can 17) of the battery having a large heat capacity, it is generated inside the battery. The heat transferred to the conductive polymer 4 and the heat generated in the conductive polymer itself, without being transferred to the exterior of the battery having a large heat capacity through the terminals, rapidly increase the temperature of the conductive polymer itself. As a result, the electric resistance of the conductive polymer rapidly increases remarkably, and overcurrent can be interrupted or the current can be greatly restricted in a short time to prevent a situation such as battery explosion. When the cause of heat generation disappears, the cathode terminal 6 is not electrically (ie, thermally) connected to the exterior of the battery having a large heat capacity (the anode inner can 16 and the anode outer can 17). The temperature of the conductive polymer falls in a short time, and the interruption or limitation of the electric current is quickly released. If the cathode terminal (or the anode terminal) using a conductive polymer is electrically (ie, thermally) connected to the exterior of the battery having a large heat capacity, an overcurrent flows in the battery. In this case, the heat generated inside the battery and transferred to the conductive polymer and the heat generated in the conductive polymer itself are transferred to the exterior of the battery having a large heat capacity through the terminals, and the temperature of the conductive polymer itself rises. The ratio of As a result, the electric resistance of the conductive polymer gradually rises, so that overcurrent cannot be interrupted or the current cannot be greatly limited in a short time, and the occurrence of a situation such as battery explosion cannot be prevented. When the cause of heat generation disappears, the cathode terminal 6 is electrically (ie, thermally) connected to the exterior (anode inner can 16 and anode outer can 17) of the battery having a large heat capacity. The temperature of the conductive polymer does not easily drop, and the current is interrupted or limited for a long time. Next, when the battery is repeatedly used for a long time under a heavy load by being used in a flash device or the like, the temperature inside the battery gradually rises with the lapse of time due to the heat generated by the use under the heavy load. To do. At this time, since the cathode terminal is not electrically connected to the exterior of the battery having a large heat capacity, the heat generated inside the battery and transferred to the conductive polymer 4 and the heat generated in the conductive polymer itself. Is gradually transferred to the exterior of the battery, but since the rate of transfer and diffusion is small, it raises the temperature of the conductive polymer itself. As a result, the electric resistance of the conductive polymer is increased, and the current can be interrupted or the current can be greatly restricted in a relatively short time to prevent the battery from exploding. If the cathode terminal (or anode terminal) using a conductive polymer was electrically connected to the exterior of a battery having a large heat capacity, it was generated inside the battery and transferred to the conductive polymer 4. Since the heat and the heat generated in the conductive polymer itself are transferred to the exterior of the battery having a large heat capacity and diffused into the outside air, the rate of temperature rise of the conductive polymer itself becomes small. As a result, the electric resistance of the conductive polymer gradually rises, so that overcurrent cannot be interrupted or the current cannot be greatly limited in a short time, and the occurrence of a situation such as battery explosion cannot be prevented. FIG. 6 shows a second embodiment in which the constitution of the cathode terminal portion in the first embodiment is changed, and the conductive polymer member 2 is provided at the connecting portion between the cathode terminal 23 and the current collecting rod 12. This is an example in which Other configurations are
This is the same as the first embodiment shown in FIG. Also in this configuration, the conductive polymer 4 is interposed between the collector terminal 12 which is a polar body on the side not electrically contacting the exterior member of the battery and the cathode terminal 23. In the above-described embodiments, the cathode terminal is not electrically connected to the exterior of the battery having a large heat capacity, but the anode terminal is electrically connected to the exterior of the battery. On the contrary, the anode terminal may be electrically connected to the outer case of the battery having a large heat capacity, and the negative terminal may be electrically connected to the outer case of the battery, and the effect is the same. As described above, according to the present invention, an anode body and a cathode body for generating an electric current, and an electric current which is connected to the anode body and the cathode body and exposed to the outside to externally supply the electric current. In a battery having an anode terminal and a cathode terminal to be taken out to and an exterior member that houses the anode body and the cathode body and one of the anode terminal and the cathode terminal is in electrical contact, the exterior member is electrically Between the terminal and the electrode body on the side of the electrode that is not in contact with the terminal, since the conductive polymer whose resistance value increases in accordance with the temperature rise is interposed.
Even if the battery heats up due to over-discharging due to the power supply short-circuit, long-term continuous heavy load use, etc., the electrical resistance will increase due to the temperature rise of the conductive polymer, and the battery and other parts will be kept at a relatively low temperature. Since the current is cut off or limited in time,
It is possible to prevent abnormal overheating of the battery, an accident due to the overheating, and damage to members that are easily damaged even at a relatively low temperature. Since the conductive polymer is interposed between the electrode body on the side not electrically connected to the exterior member and the terminal, the electrode body and the terminal on the side electrically connected to the exterior member are provided. The current can be interrupted or limited in a short time as compared with the one interposed between and, and when the cause of heat generation is eliminated, the recovery can be performed quickly. further,
In addition to the above-mentioned structure that cuts off or greatly limits the overcurrent due to the conductive polymer, the structure that the short circuit of the electrode does not easily occur by covering the outer surface of the battery exterior member with the insulating member is added, and the double safety By adopting the structure, it is possible to further reduce the probability of occurrence of an accident due to a short circuit of the electrodes, and it is possible to achieve remarkable effects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of the configuration of a battery provided with a conventional overheat prevention device. FIG. 2 is an explanatory diagram showing characteristics of a conductive polymer. FIG. 3 is an explanatory diagram showing characteristics of a conductive polymer. FIG. 4 is a perspective view showing a configuration of a conductive polymer member. FIG. 5 is a sectional view showing the configuration of the first embodiment of the present invention. FIG. 6 is a sectional view showing the structure of a second embodiment of the present invention. [Description of Reference Signs] 2 conductive polymer member 4 conductive polymer 5 conductive plate 6 cathode terminal 10 anode, anode material 11 cathode, cathode material 12 current collector bar 13 separator 15 sealing body packing 16 anode inner can 17 anode outer can 18 insulation Plate 19 Anode terminal

   ────────────────────────────────────────────────── ─── Continuation of front page        Panel     Referee Chief Haruo Oya     Hideyuki Ono, Judge     Judge Yamada Yasushi (56) References JP-A-58-188066 (JP, A)                 Actual development Sho 59-144875 (JP, U)                 59-144876 (JP, U)                 Tokyo High Court Decision, 8, 5, 30, 6 (line               Ke) 97

Claims (1)

(57) [Claims] An anode body and a cathode body for generating an electric current, an anode terminal and a cathode terminal which are connected to the anode body and the cathode body and take out a current by being exposed to the outside, and the anode body and the cathode body are housed. In addition , in a battery having an exterior member in which one of the anode terminal and the cathode terminal is electrically connected, the exterior surface of the exterior member is covered with an insulating member,
Two, between the electrode side electrode body not electrically connected to the exterior member and the terminal, a conductive polymer whose resistance value increases in accordance with a temperature rise is interposed. A battery having an over-discharge overheat protection device.