JP5049066B2 - Electrical equipment and battery pack - Google Patents

Description

  The present invention relates to an electric device using a battery and a battery pack.

  Conventionally, a battery has been widely used as a power source for electrical equipment. As an electric device using such a battery as a power source, for example, an electric device having a structure in which a primary battery can be replaced with an accommodating portion for accommodating the primary battery, or a rechargeable secondary battery in the main body Etc.

  In addition, portable electric devices typified by mobile phones and digital cameras are sought to be highly functional, and power consumption of the devices tends to increase. Therefore, it is desirable that the main power source of such a highly functional portable electric device has a large capacity and a high energy density. The main power source of portable electric equipment is a secondary battery, but the secondary battery is charged by a charging device connected to a commercial AC power source, or the so-called AC that converts the commercial AC power source voltage into a DC voltage for charging. It is necessary to charge with a power supply device called an adapter, and if it is taken out outdoors, the secondary battery cannot be charged, which is inconvenient. Therefore, in recent years, there has been known a device in which a secondary battery is charged using an auxiliary power source that can be attached to and detached from such a portable electric device. A primary battery is used as such an auxiliary power source.

  However, if the primary battery or secondary battery used as the main power source in the above-described electrical equipment and the primary battery used as the auxiliary power source remain connected to the circuit of the electrical equipment, the leakage current There is a possibility that the discharge continues and an overdischarge state occurs. And these batteries have the subject that when it becomes an overdischarge state, there exists a possibility that it may deteriorate and liquid leakage and a rapid temperature rise may generate | occur | produce.

  FIG. 6 is a graph showing changes in output voltage and electrode potential (potential with respect to HgO / Hg) when an alkaline battery, which is an example of a primary battery, is continuously discharged at a constant current. 6A shows changes in the output voltage of the alkaline battery, and FIG. 6B shows changes in the positive electrode potential and the negative electrode potential of the alkaline battery.

  In the case of an alkaline battery, the positive electrode is a manganese electrode and the negative electrode is a zinc electrode. Further, the difference between the potential of the manganese electrode and the potential of the zinc electrode shown in FIG. 6B corresponds to the output voltage of the alkaline battery shown in FIG. As the alkaline battery discharges, the manganese electrode potential gradually decreases, the zinc electrode potential gradually increases, the output voltage decreases, and the discharge end voltage is the lowest voltage at which the output voltage can be safely discharged. When the value reaches, the zinc electrode potential exceeds the hydrogen gas generation potential, and hydrogen gas is generated from the zinc electrode.

  Furthermore, when the discharge of the alkaline battery continues, the potential of the manganese electrode gradually decreases, while the potential of the zinc electrode increases rapidly, and hydrogen gas continues to be generated from the zinc electrode. The potential of the manganese electrode is stabilized in a certain range of −0.4 V to −0.3 V, but the potential of the zinc electrode is further increased, and the potential of the zinc electrode is higher than that of the manganese electrode. Thus, a so-called inversion with the zinc electrode as the positive electrode occurs, and the output voltage of the alkaline battery becomes negative. Then, since the potential of the manganese electrode serving as the negative electrode is higher than the hydrogen gas generation potential, hydrogen gas is generated from the manganese electrode.

  As described above, when the alkaline battery continues to be discharged due to the leakage current of the circuit, hydrogen gas is generated inside the battery, which may increase the pressure of the battery and cause liquid leakage.

  FIG. 7 is a graph showing a change in output voltage when a lithium battery, which is an example of a primary battery, is continuously discharged at a constant current. In the case of a lithium battery, the positive electrode is a manganese electrode and the negative electrode is a lithium electrode. As the lithium battery is discharged, the output voltage gradually decreases. And until the output voltage of the battery reaches 0V, the lithium electrode dissolves but the lithium dendrite does not deposit on the manganese electrode.

  When the output voltage of the battery falls below 0 V and inversion occurs, lithium dendrite is deposited on the manganese electrode, and further, lithium dissolution and precipitation reactions occur on both the lithium electrode and the manganese electrode. Thereafter, the dissolution and precipitation reaction of lithium reaches an equilibrium between the lithium electrode and the manganese electrode, and the battery voltage becomes temporarily constant. In this case, after the reversal occurs, the deposited lithium dendrite penetrates the separator, the lithium electrode and the manganese electrode are short-circuited, a short-circuit current flows, and the temperature of the lithium battery may increase rapidly.

  Furthermore, in the lithium battery in the above reversal state, if the lithium battery continues to be discharged even if the lithium battery does not short-circuit while the battery voltage is constant, the iron from the lithium battery case, current collector, etc. Dissolution of (Fe) and precipitation of iron occur. Then, the deposited iron penetrates the separator, the lithium electrode and the manganese electrode are short-circuited, a short-circuit current flows, and the temperature of the lithium battery may rapidly increase.

As described above, when the battery is overdischarged, there is a risk of leakage or rapid temperature rise, and various methods have been proposed as countermeasures. For example, a device that prevents overdischarge of a battery by incorporating an overdischarge protection circuit inside the battery is known (for example, see Patent Document 1). Further, as a method for suppressing leakage due to overdischarge of an alkaline battery, there is a method of absorbing hydrogen gas generated from the inside of the battery. Reference 2), and those using a hydrogen adsorption catalyst inside an alkaline battery (for example, see Patent Document 3) have been proposed.
Special Table 2002-525806 JP 07-272770 A JP 2004-502280 A

  However, as disclosed in Patent Document 1, a battery that uses an overdischarge protection circuit to prevent overdischarge is certainly a high-resistance element in a battery in which the overdischarge protection circuit is activated. There was a possibility of continuing to flow. Therefore, when a plurality of batteries are connected in series, if the series circuit remains connected while the overdischarge protection circuit is activated with any one battery, other capacity remains. There was a problem of being continuously discharged by the battery.

  In addition, as in the techniques described in Patent Document 2 and Patent Document 3, the one that absorbs hydrogen gas generated from the inside of the alkaline battery is hydrogen gas when hydrogen gas is generated exceeding the hydrogen adsorption capacity of the hydrogen adsorbing material. Since the gas could not be completely absorbed, there was a problem that the hydrogen gas that could not be absorbed increased the pressure of the battery and could cause liquid leakage.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric device and a battery pack that can reduce the risk of sudden temperature rise and leakage of the battery. To do.

  The electrical device according to the present invention is configured to supply power from a positive electrode terminal for connecting to a positive electrode of a battery, a negative electrode terminal for connecting to a negative electrode of the battery, and the positive electrode terminal and the negative electrode terminal to which a battery is connected. When the load circuit to be supplied, the voltage detection unit for detecting the voltage between the positive electrode terminal and the negative electrode terminal, and the voltage detected by the voltage detection unit is equal to or lower than a preset set voltage, A short-circuit portion that short-circuits the positive electrode terminal and the negative electrode terminal.

  According to this configuration, when a battery is connected to the positive electrode terminal and the negative electrode terminal, power is supplied from the battery to the load circuit via the positive electrode terminal and the negative electrode terminal. And the voltage between a positive electrode terminal and a negative electrode terminal, ie, the output voltage of a battery, is detected by the voltage detection part. Furthermore, when the voltage detected by the voltage detector is equal to or lower than a preset voltage, the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit unit, so that the battery connected to the positive electrode terminal and the negative electrode terminal As a result of the discharge and the positive electrode and the negative electrode of the battery being made to have the same potential and the occurrence of inversion are suppressed, the risk of sudden temperature rise and leakage of the battery can be reduced.

  Further, the power storage device may further include a power storage element that stores power, and the load circuit may include a charging unit that charges the power storage element based on output power of a battery connected between the positive electrode terminal and the negative electrode terminal. . According to this configuration, it is possible to reduce the risk of sudden temperature rise or leakage of the battery used as the auxiliary power source for charging the power storage element used as the main power source of the load circuit.

  Moreover, it is preferable that the said electrical storage element supplies the power supply voltage for operation | movement of the said voltage detection part. According to this configuration, even if the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit unit and the output power of the battery cannot be obtained, the operation power supply voltage of the voltage detection unit is supplied from the storage element. Therefore, even when the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit unit, the supply of the operating power supply voltage to the voltage detection unit is not interrupted, and the voltage detection unit between the positive electrode terminal and the negative electrode terminal is not interrupted. As a result of the continuous voltage detection, it is possible to maintain the short-circuit operation between the positive electrode terminal and the negative electrode terminal by the short-circuit portion.

  Moreover, it is preferable that the said setting voltage is set to the discharge end voltage of the said battery. According to this configuration, after the battery is used until the output voltage of the battery becomes a discharge end voltage that is not suitable for use of the battery, the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit portion, and the battery is discharged. Since the positive electrode and the negative electrode are set to the same potential and the occurrence of inversion is suppressed, it is possible to reduce the risk of sudden battery temperature rise and leakage while using the battery capacity without waste.

  Further, the set voltage may be set to a charging lower limit voltage that is a lower limit value of the output voltage at which the charging unit can charge the storage element based on the output voltage of the battery.

  According to this configuration, the battery is discharged after the battery is used until the output voltage of the battery reaches a charging lower limit voltage at which the storage element cannot be charged by the charging unit, and then the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit unit. Since the positive electrode and the negative electrode of the battery are made to have the same potential and the occurrence of inversion is suppressed, there is a risk of sudden increase in battery temperature or leakage while using the battery capacity for charging the storage element without waste. Can be reduced.

  The battery is preferably an alkaline primary battery. According to this configuration, when the output voltage of the alkaline primary battery is equal to or lower than a preset set voltage, the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit portion, and thus connected to the positive electrode terminal and the negative electrode terminal. As a result of the alkaline primary battery being discharged, the positive electrode and the negative electrode of the alkaline primary battery are set to the same potential and the occurrence of inversion is suppressed, hydrogen gas is generated inside the alkaline primary battery, and the pressure of the battery increases. The risk of liquid leakage is reduced.

  The battery may be a lithium battery. According to this configuration, when the output voltage of the lithium battery is equal to or lower than the preset voltage, the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit portion, so that the lithium connected to the positive electrode terminal and the negative electrode terminal As the battery is discharged and the positive and negative electrodes of the lithium battery are set to the same potential and the occurrence of inversion is suppressed, precipitation of lithium dendrite is reduced and the lithium and manganese electrodes are short-circuited by the lithium dendrite. Short circuit current flows, and the risk of the temperature of the lithium battery rising rapidly is reduced.

  In addition, the short-circuit unit is configured such that when the voltage detected by the voltage detection unit is equal to the set voltage, the resistor passes a time rate current of 1 μC or more and 1 C or less with respect to the nominal capacity of the battery. It is preferable to short-circuit the positive electrode terminal and the negative electrode terminal.

  According to this configuration, at least when the positive electrode terminal and the negative electrode terminal are short-circuited by the short-circuit portion and the discharge of the battery is started, the resistance is limited to the extent that the discharge current does not become excessive, and the nominal capacity of the battery is reached. On the other hand, since a time rate current of 1 μC or more and 1 C or less can be flowed, precipitation of lithium can be effectively reduced particularly when a lithium battery is connected between the positive electrode terminal and the negative electrode terminal. As a result, the lithium electrode and the manganese electrode are short-circuited by the lithium dendrite, a short-circuit current flows, and the possibility that the temperature of the lithium battery rapidly increases is reduced.

  Moreover, it is preferable that the said battery is comprised by the single cell. When the battery is configured by connecting a plurality of cells in series, inversion may occur in some of the cells connected in series even if the positive electrode terminal and the negative electrode terminal are short-circuited. However, according to this configuration, since the battery is configured by a single cell, the positive electrode terminal and the negative electrode terminal are short-circuited, thereby increasing the certainty that the inversion is prevented.

  The battery may be configured by connecting a plurality of cells in parallel. When the battery is configured by connecting a plurality of cells in series, inversion may occur in some of the cells connected in series even if the positive electrode terminal and the negative electrode terminal are short-circuited. However, according to this configuration, since the battery is configured by connecting a plurality of cells in parallel, the positive electrode terminal and the negative electrode terminal are short-circuited, thereby increasing the certainty that the inversion is prevented. Is done.

  The battery pack according to the present invention includes a battery, a voltage detection unit that detects an output voltage of the battery, and the voltage detected by the voltage detection unit when the voltage detected by the voltage detection unit is equal to or lower than a preset voltage. A short-circuit unit for short-circuiting and an external output terminal for outputting the output power of the battery to the outside.

  According to this configuration, the voltage detection unit detects the output voltage of the battery that outputs power to the outside via the external output terminal. When the voltage detected by the voltage detection unit is equal to or lower than a preset voltage, the battery is short-circuited by the short-circuit unit. As a result, the battery is discharged, and the positive electrode and the negative electrode of the battery are set to the same potential. Since the occurrence of inversion is suppressed, it is possible to reduce the risk of rapid battery temperature rise or leakage.

  When the output voltage of the battery is less than the preset voltage, the electric device and the battery pack having such a configuration are short-circuited by the short-circuit unit, so that the battery is discharged, and the positive and negative electrodes of the battery Since the occurrence of inversion is suppressed at the same potential, it is possible to reduce the risk of rapid battery temperature rise or leakage.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram illustrating an example of the configuration of an electrical device according to an embodiment of the present invention. An electric device 1 shown in FIG. 1 is a portable electric device using a secondary battery such as a mobile phone or a digital camera as a power source. 1 includes, for example, a positive electrode terminal 11, a negative electrode terminal 12, an external power supply connection terminal 13, a short circuit unit 2, a voltage detection unit 3, a charging circuit 4 (charging unit), and a secondary battery 5. Yes. Further, the electric device 1 can charge the secondary battery 5 serving as the main power source by the output power from the primary battery 6 (battery) which is an auxiliary power source connected to the outside by the positive electrode terminal 11 and the negative electrode terminal 12. It is like that.

  The secondary battery 5 is a secondary battery that can be used for a charge / discharge cycle, such as a lithium ion battery, a nickel metal hydride battery, a nickel cadmium battery, a nickel zinc battery, or a silver oxide battery. In this case, the secondary battery 5 corresponds to an example of a power storage element. The storage element is not limited to the secondary battery, and may be a capacitor such as an electric double layer capacitor. The secondary battery 5 is used as a main power source of the electric device 1 and supplies electric power to a load circuit (not shown) for operating the electric device 1 as, for example, a mobile phone or a digital camera.

  The external power supply connection terminal 13 is a connector configured to be detachable from the AC adapter 7, for example. The AC adapter 7 converts, for example, a commercial AC power supply voltage AC of 100 V AC into a DC voltage for charging the secondary battery 5 and outputs it to the secondary battery 5 via the external power connection terminal 13. A power supply circuit for charging. When the user can use a commercial AC power source, for example, at home or in the office, the AC adapter 7 can be connected to the external power connection terminal 13 and the secondary battery 5 can be charged by the AC adapter 7.

  The primary battery 6 may be an alkaline battery such as an alkaline manganese battery, a nickel manganese battery, an air zinc battery, or a silver oxide battery, or a lithium battery such as a manganese dioxide lithium battery or a graphite fluoride lithium battery. May be. The primary battery 6 is used, for example, by being accommodated in a battery holder (not shown) configured to be detachable from the electric device 1, for example, by attaching a battery holder (not shown) containing the primary battery 6 to the electric device 1. The positive electrode of the battery 6 is connected to the short-circuit unit 2, the voltage detection unit 3, and the charging circuit 4 through the positive electrode terminal 11, and the negative electrode of the primary battery 6 is connected to the ground through the negative electrode terminal 12. ing.

  The charging circuit 4 is configured using, for example, a DC-DC converter, and receives power output from the primary battery 6 via the positive terminal 11 and the negative terminal 12 and is suitable for charging the secondary battery 5. The secondary battery 5 is charged by converting into voltage. In order for the charging circuit 4 to operate and charge the secondary battery 5, the voltage between the positive terminal 11 and the negative terminal 12, that is, the output voltage V <b> 1 of the primary battery 6 needs to be within a certain voltage range. It is.

  Here, the lower limit value of the voltage at which the charging circuit 4 operates to charge the secondary battery 5 is defined as a charging lower limit voltage Vlim. If the output voltage V1 of the primary battery 6 exceeds the charging lower limit voltage Vlim, the charging circuit 4 causes the current for charging the secondary battery 5 to flow from the primary battery 6 to the charging circuit 4. On the other hand, if the output voltage V1 of the primary battery 6 is equal to or lower than the charging lower limit voltage Vlim, the charging circuit 4 stops the charging operation of the secondary battery 5. Then, the current flowing from the primary battery 6 to the charging circuit 4 is only the leakage current of the charging circuit 4, and a very small current continues to flow from the primary battery 6 to the charging circuit 4. The charge lower limit voltage Vlim is set to, for example, the discharge end voltage of the primary battery 6. In this case, the charging circuit 4 corresponds to an example of a load circuit.

  The short-circuit unit 2 is configured by connecting a series circuit of a resistor R6 and a transistor Tr2 between a positive electrode terminal 11 and a negative electrode terminal 12. When the transistor Tr2 is turned on, the primary battery 6 is connected via the resistor R6. A short circuit path for discharging is generated. As the transistor Tr2, a field effect transistor (FET) capable of flowing a current in both directions is used. For example, a relay switch may be used instead of the transistor Tr2.

  The resistor R6 is a current limiting resistor for preventing a rapid increase in temperature due to the discharge current of the primary battery 6, and the resistance value is as small as possible while suppressing the discharge current to such an extent that the primary battery 6 does not rapidly increase in temperature. It is desirable to set. Moreover, when the primary battery 6 is a lithium battery, when a time rate current of 1 μC or more and 1 C or less is applied to the nominal capacity of the lithium battery, dissolution and precipitation of lithium can be effectively reduced. Therefore, for example, when the nominal capacity of the primary battery 6 is 3000 mAh and the charging lower limit voltage Vlim is 1.0 V, the resistance R6 is, for example, 1.0 μC or more and 1 C or less with respect to the nominal capacity of the lithium battery at 1.0 V. A resistance value capable of flowing a time rate current, for example, a resistance value of 100Ω or less is set. Here, C represents the magnitude of the discharge current of the battery, and C = It.

  Thereby, when the transistor Tr2 is turned on, the positive electrode terminal 11 and the negative electrode terminal 12 are short-circuited via the resistor R6, and the positive electrode and the negative electrode of the primary battery 6 connected to the positive electrode terminal 11 and the negative electrode terminal 12 reduce the resistor R6. Therefore, the positive electrode potential is suppressed to be lower than the negative electrode potential, and the occurrence of inversion is suppressed.

  The voltage detection unit 3 detects the output voltage V1 of the primary battery 6 connected to the positive electrode terminal 11 and the negative electrode terminal 12, and short-circuits to the short circuit unit 2 when the output voltage V1 is equal to or lower than the charging lower limit voltage Vlim (set voltage). Therefore, the detection signal is output to the short-circuit unit 2. Specifically, the voltage detection unit 3 includes, for example, resistors R1, R2, R3, R4, R5, an operational amplifier OP1, and a transistor Tr1. The power supply voltage for operation of the operational amplifier OP1 is supplied from the secondary battery 5. Further, the output voltage of the secondary battery 5 is divided by the resistors R1 and R2 to be the reference voltage Vref. The resistance values of the resistors R1 and R2 are set in advance so that the reference voltage Vref is, for example, 1/2 of the charging lower limit voltage Vlim.

  Then, the reference voltage Vref obtained by the resistors R1 and R2 is applied to the inverting input terminal of the operational amplifier OP1. Further, the voltage between the positive terminal 11 and the negative terminal 12, that is, the output voltage V1 of the primary battery 6, is divided by resistors R3 and R4, and the divided voltage V2 is applied to the non-inverting input terminal of the operational amplifier OP1. . The resistance values of the resistors R3 and R4 are set in advance so that the divided voltage V2 is, for example, 1/2 of the output voltage V1.

  In this case, even if the output voltage of the secondary battery 5 or the output voltage V1 of the primary battery 6 exceeds the voltage that can be processed by the operational amplifier OP1, the output voltage of the secondary battery 5 is divided by the resistors R1 and R2. By dividing the output voltage V1 of the primary battery 6 with the resistors R3 and R4, it is possible to step down to a voltage level that can be processed by the operational amplifier OP1.

  It is not always necessary to divide the output voltage of the secondary battery 5 by the resistors R1 and R2 to generate the reference voltage Vref, and the reference voltage Vref may be generated using a constant voltage circuit. Further, if the output voltage V1 of the primary battery 6 is within a voltage level that can be processed by the operational amplifier OP1, it is not always necessary to divide the voltage by the resistors R3 and R4, and the output voltage V1 is directly applied to the non-inverting input terminal of the operational amplifier OP1. May be applied. In this case, the charging lower limit voltage Vlim may be generated using a constant voltage circuit and applied to the inverting input terminal of the operational amplifier OP1.

  The emitter of the transistor Tr1 is connected to the positive electrode of the secondary battery 5, the collector of the transistor Tr1 is connected to the gate of the transistor Tr2, and is connected to the ground via the resistor R5. The base of the transistor Tr1 is the output terminal of the operational amplifier OP1. It is connected to the.

  Next, the operation of the electric device 1 configured as described above will be described. FIG. 2 is an explanatory diagram showing the relationship between the output voltage V1 of the primary battery 6 and the on / off operation of the transistor Tr2. FIG. 3 is an explanatory diagram showing the relationship between the output voltage V1 of the primary battery 6 and the discharge current of the primary battery 6. First, when the user connects the primary battery 6 to the positive electrode terminal 11 and the negative electrode terminal 12 in order to charge the secondary battery 5 in an environment where the commercial AC power supply or the AC adapter 7 cannot be used, for example, outdoors, the output of the primary battery 6 The voltage V <b> 1 is applied to the charging circuit 4, the voltage detection unit 3, and the short circuit unit 2.

  If the output voltage V1 of the primary battery 6 exceeds the charging lower limit voltage Vlim, for example, exceeds 1.0V, the divided voltage V2 also exceeds the reference voltage Vref, and the output signal of the operational amplifier OP1 is at a high level. Is output to the base of the transistor Tr1, the transistor Tr1 is turned off, and the gate voltage of the transistor Tr2 is set to a low level by the resistor R5. Then, when the output voltage V1 exceeds the charging lower limit voltage Vlim, the transistor Tr2 is turned off as shown in FIG. Then, as shown in FIG. 3, the primary battery 6 is not discharged, and the discharge current flowing through the short-circuit portion 2 becomes substantially zero. In this case, since the output voltage V1 of the primary battery 6 exceeds the charging lower limit voltage Vlim, the secondary battery 5 is charged by the charging circuit 4 based on the output power of the primary battery 6.

  On the other hand, when the output voltage V1 of the primary battery 6 becomes the charging lower limit voltage Vlim, for example, a voltage of 1.0 V or less, the divided voltage V2 also becomes the reference voltage Vref or less, so that the output signal of the operational amplifier OP1 is low and the transistor Tr1 The transistor Tr1 is turned on, and the gate voltage of the transistor Tr2 is set to the high level. Then, as shown in FIG. 2, when the output voltage V1 is equal to or lower than the charging lower limit voltage Vlim, the transistor Tr2 is turned on. Then, as shown in FIG. 3, the primary battery 6 is discharged by the short-circuit portion 2, the output voltage V1 decreases along with the discharge, and the discharge current of the primary battery 6 decreases as the output voltage V1 decreases. And when the output voltage V1 becomes 0V, the discharge current which flows through the short circuit part 2 will also be 0A.

  FIG. 4 is a graph showing changes in the output voltage V1 and the electrode potential of the primary battery 6 (potential with respect to HgO / Hg) when an alkaline battery is used as the primary battery 6. 4A shows changes in the output voltage V1, and FIG. 4B shows changes in the potential of the manganese electrode that is the positive electrode of the primary battery 6 and the potential of the zinc electrode that is the negative electrode. In FIG. 4A, the end-of-charge voltage of the primary battery 6 is 1.0 V, for example, and the lower limit charge voltage Vlim is set to 1.0 V, which is equal to the end-of-charge voltage of the primary battery 6.

  The difference between the potential of the manganese electrode and the potential of the zinc electrode shown in FIG. 4 (b) corresponds to the output voltage V1 of the primary battery 6 shown in FIG. 4 (a). As the electric power is supplied from the primary battery 6 to the charging circuit 4, the potential of the manganese electrode gradually decreases, the potential of the zinc electrode gradually increases, and the output voltage V1 gradually decreases. When the output voltage V1 becomes the charging lower limit voltage Vlim, that is, 1.0 V or less, the divided voltage V2 also becomes the reference voltage Vref or less, so that the output signal of the operational amplifier OP1 is output to the base of the transistor Tr1 at a low level. The transistor Tr1 is turned on, and the gate voltage of the transistor Tr2 is set to the high level.

  Then, the transistor Tr2 is turned on and the primary battery 6 is discharged. And the electric potential of a manganese electrode (positive electrode) falls, and the electric potential of a zinc electrode (negative electrode) rises temporarily. Further, when the discharge of the primary battery 6 progresses and the output voltage V1 becomes 0V, the transistor Tr2 is a field effect transistor, and current flows in both directions. Therefore, when the output voltage V1 falls below 0V and becomes negative, the transistor Tr2 is reversed. As a result of the current flowing, the output voltage V1 is maintained at 0V. If it does so, the impedance of a manganese electrode and a zinc electrode will increase gradually, and the output current of the primary battery 6 will reduce gradually.

  When the output current of the primary battery 6 decreases, the potential of the zinc electrode decreases, the potential of the manganese electrode decreases as the zinc electrode changes in potential, and both are constant at a potential higher than the hydrogen gas generation potential. Such potential change is due to the fact that the discharge reaction of the zinc electrode is a heterogeneous reaction in which zinc on the zinc electrode is oxidized to zinc oxide. This is because the potential of the zinc electrode recovers to the potential of unreacted zinc. Thereby, generation | occurrence | production of hydrogen gas can be suppressed by maintaining the electric potential of a manganese electrode and a zinc electrode in an electric potential higher than a hydrogen gas generation potential, and the possibility that the liquid leakage of a battery may generate | occur | produce can be reduced.

  Similarly, when a lithium battery is used as the primary battery 6, the output voltage V 1 becomes equal to or lower than the charging lower limit voltage Vlim, the transistor Tr 2 is turned on by the voltage detection unit 3, and the discharge of the primary battery 6 proceeds. When the output voltage V1 becomes 0V, the transistor Tr2 passes a current in both directions. Therefore, when the output voltage V1 falls below 0V and becomes negative, a current flows in the opposite direction. As a result, the output voltage V1 does not become negative. It is maintained at 0V. Then, since the reversal of the potential of the manganese electrode (positive electrode) and the potential of the lithium electrode (negative electrode) is suppressed, the dissolution of the lithium electrode is suppressed. As a result, the precipitation of lithium dendrite on the manganese electrode and the lithium electrode is suppressed. Is done. Thereby, the lithium electrode and the manganese electrode are short-circuited by the deposited lithium dendrite, a short-circuit current flows, and the possibility that the temperature of the lithium battery rapidly increases is reduced.

  Furthermore, by suppressing the reversal of the potential of the manganese electrode (positive electrode) and the potential of the lithium electrode (negative electrode), the dissolution of iron (Fe) from the case of the lithium battery, the current collector, etc. Deposition is suppressed, and the lithium electrode and the manganese electrode are short-circuited by the deposited iron and a short-circuit current flows. As a result, the risk of the temperature of the lithium battery rising rapidly is reduced.

  The primary battery 6 is preferably composed of a single cell or a plurality of cells connected in parallel. When the primary battery 6 is configured by, for example, a plurality of cells connected in series, even if the output terminals of the primary battery 6 are short-circuited by the short-circuit portion 2, some of the cells connected in series There is a risk of inversion.

  As shown in FIG. 5, the primary battery 6, the short-circuit portion 2, and the voltage detection portion 3 shown in FIG. 1 may be housed in a single housing and configured as a battery pack 8. The battery pack 8 shown in FIG. 5 receives external power terminals 14 and 15 for outputting the output power of the primary battery 6 to the outside and the power for operation of the voltage detection unit 3 from the electric device 1a, and the voltage detection unit. 3 is provided with a connection terminal 16 to be supplied to 3.

  Moreover, the electric device using the battery pack 8 removes the short-circuit portion 2 and the voltage detection portion 3 from the electric device 1 shown in FIG. 1 as in the electric device 1a shown in FIG. It may be provided. In this case, the battery pack 8 is configured to be attachable to the electric device 1a. When the battery pack 8 is attached to the electric device 1a, the external output terminals 14 and 15 are connected to the connection terminals 17 and 18, respectively. The connection terminal 16 is connected to the connection terminal 19. Since the battery pack 8 is attached to the electric device 1a, a circuit similar to the electric device 1 shown in FIG. 1 is configured. Therefore, as with the electric device 1 shown in FIG. The possibility that a serious temperature rise will occur can be reduced.

In addition, although the electric equipment 1 showed the example which uses the primary battery 6 as an auxiliary power supply which charges a main power supply, it is good also as a structure which does not use an auxiliary power supply and therefore does not include the charging circuit 4. Specifically, for example, the short-circuit unit 2 is configured to short-circuit between the positive electrode and the negative electrode of the secondary battery 5, and the voltage detection unit 3 satisfies the output voltage of the secondary battery 5 to the end-of-discharge voltage. If not, the transistor Tr2 may be turned on. In this case, the secondary battery 5 corresponds to an example of a battery according to the claims.
Further, in such a configuration that does not use the auxiliary power source, a primary battery may be used as the main power source instead of the secondary battery 5. In this case, when the output voltage of the main power source constituted by a battery such as the secondary battery 5 or the primary battery falls below the discharge end voltage, the battery of the main power source is short-circuited by the short-circuit portion 2 via the resistor R6 and Since generation | occurrence | production is suppressed, a possibility that a battery may leak or a temperature rises rapidly is reduced.

  The present invention can be applied to an electric device using a battery and a battery pack used for such an electric device.

It is a block diagram which shows an example of a structure of the electric equipment which concerns on one Embodiment of this invention. FIG. 2 is an explanatory diagram showing a relationship between an output voltage of the primary battery shown in FIG. 1 and ON / OFF operation of a transistor. It is explanatory drawing which shows the relationship between the output voltage of the primary battery shown in FIG. 1, and the discharge current of a primary battery. It is a graph which shows the change of the output voltage and the electrode potential (potential with respect to HgO / Hg) of a primary battery at the time of using an alkaline battery as a primary battery shown in FIG. (A) shows the change in the output voltage, and (b) shows the change in the potential of the manganese electrode that is the positive electrode of the primary battery and the potential of the zinc electrode that is the negative electrode. It is a block diagram which shows an example of a structure of the battery pack which concerns on one Embodiment of this invention. It is a graph which shows the change of an output voltage and electrode potential (potential with respect to HgO / Hg) when the alkaline battery which concerns on background art discharges with the leakage current of a circuit. (A) shows the change in the output voltage of the alkaline battery, and (b) shows the change in the positive electrode potential and the negative electrode potential of the alkaline battery. It is a graph which shows the change of an output voltage when the lithium battery which concerns on background art discharges by the leakage current of a circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Electric equipment 2 Short circuit part 3 Voltage detection part 4 Charging circuit 5 Secondary battery 6 Primary battery 8 Battery pack 11 Positive electrode terminal 12 Negative electrode terminal 13 External power supply connection terminal 14,15 External output terminal 16,17,18,19 Connection Terminal OP1 Operational amplifier R1, R2, R3, R4, R5, R6 Resistor Tr1, Tr2 Transistor

Claims (11)

A positive terminal for connection to the positive electrode of the battery;
A negative electrode terminal for connection to the negative electrode of the battery;
A load circuit to which electric power is supplied from the positive electrode terminal and the negative electrode terminal to which a battery is connected,
A voltage detector for detecting a voltage between the positive terminal and the negative terminal;
An electrical apparatus comprising: a short-circuit unit that short-circuits the positive terminal and the negative terminal when the voltage detected by the voltage detection unit is equal to or lower than a preset set voltage. It further includes a power storage element that stores electric power,
The electric device according to claim 1, wherein the load circuit includes a charging unit that charges the power storage element based on output power of a battery connected between the positive electrode terminal and the negative electrode terminal. The electric device according to claim 2, wherein the power storage element supplies a power supply voltage for operation of the voltage detection unit. The electric device according to any one of claims 1 to 3, wherein the set voltage is set to a discharge end voltage of the battery. The setting voltage is set to a charging lower limit voltage that is a lower limit value of the output voltage at which the charging unit can charge the storage element based on an output voltage of the battery. Or the electrical equipment of 3. The electric device according to claim 1, wherein the battery is an alkaline primary battery. The electric device according to claim 1, wherein the battery is a lithium battery. When the voltage detected by the voltage detection unit is equal to the set voltage, the short-circuit unit is connected to the positive electrode terminal via a resistor that flows a current with a time ratio of 1 μC or more and 1 C or less with respect to the nominal capacity of the battery. The electrical apparatus according to claim 1, wherein the negative electrode terminal is short-circuited. The electric device according to any one of claims 1 to 8, wherein the battery includes a single cell. The electric device according to any one of claims 1 to 8, wherein the battery includes a plurality of cells connected in parallel. Battery,
A voltage detector for detecting an output voltage of the battery;
When the voltage detected by the voltage detection unit is equal to or lower than a preset voltage, a short-circuit unit that short-circuits the battery;
An external output terminal for outputting the output power of the battery to the outside.

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