JP2005218174A5 - - Google Patents

Description

Battery pack monitoring device, battery pack and power tool

  The present invention relates to a technique for preventing overcharge and overdischarge of a rechargeable unit battery constituting an assembled battery.

Japanese Laid-Open Patent Publication No. 9-140067 discloses a battery monitoring circuit that detects the voltage of each unit battery while charging or discharging the assembled battery in an assembled battery in which a plurality of rechargeable unit batteries are connected in series. (See Patent Document 1). The battery monitoring circuit is configured to output information indicating the voltage value of each unit battery. Alternatively, the battery monitoring circuit is configured to output information indicating the voltage value of the unit battery having the lowest voltage value when the assembled battery is being discharged. On the side of the device to which the assembled battery is connected (the charger or the operating device driven by using the assembled battery as a driving power source), charging or discharging is stopped based on these pieces of information, and each unit battery constituting the assembled battery is Overcharge and overdischarge are prevented.
Japanese Patent Laid-Open No. 9-140067

In order to prevent overdischarge or overcharge of each unit battery using such a battery monitoring circuit, on the device side to which the assembled battery is connected, charging or discharging is stopped based on the above information output by the battery monitoring circuit. A configuration to do was needed. That is, when a device that does not have the above configuration is connected to the assembled battery, overdischarge or overcharge of each unit battery cannot be prevented based on the above information.
The present invention has been made in view of the above points, and provides a technique that contributes to easily dealing with overcharge and overdischarge of unit cells constituting the assembled battery on the device side to which the assembled battery is connected. Is the purpose.

In order to achieve the above object, the invention described in each claim is configured.
(Invention of Claim 1)
According to the first aspect of the present invention, when the temperature of the assembled battery constituted by the rechargeable unit battery exceeds a predetermined reference value, the assembled battery temperature index indicating that the assembled battery is in a high temperature state is provided. An assembled battery monitoring device for outputting is configured.
The rechargeable unit battery includes all unit batteries that can be repeatedly charged and used, such as a lithium ion battery, a nickel metal hydride battery, and a nickel cadmium battery.

  When the assembled battery is configured by a plurality of unit batteries, the same type of unit batteries may be combined, or different types of unit batteries may be combined. Furthermore, the unit cells may be connected to each other in series or may be connected in parallel.

  As for the temperature of the assembled battery, the temperature of the body of the assembled battery, the temperature of the unit battery having the characteristic that the temperature is most likely to rise in the assembled battery, the body of the unit battery whose temperature is likely to rise depending on the position of the battery And all the cases such as the temperature in the vicinity thereof. Typically, when a battery pack is formed by connecting a lithium ion battery and a nickel metal hydride battery in series, the temperature in the vicinity of the nickel metal hydride battery that is relatively likely to rise due to charging is detected.

The “assembled battery temperature index” includes all indices that can indicate that the assembled battery is in a high temperature state when the temperature of the assembled battery exceeds a predetermined reference value. Typically, the assembled battery temperature index is configured as an output signal of a thermistor provided in the vicinity of the assembled battery. Among the thermistors, for example, a thermistor having a negative temperature characteristic (generally referred to as an NTC thermistor) has a characteristic that the impedance value decreases as the temperature rises. That is, the impedance value of the thermistor is high when the assembled battery is in a low temperature state, and the impedance value of the thermistor is low when the assembled battery is in a high temperature state compared to when the assembled battery is in a low temperature state. When such a thermistor is used, a battery charger for charging an assembled battery typically has an assembled battery in a high temperature state when the voltage value (assembled battery temperature index) at both ends of the thermistor is equal to or lower than a predetermined voltage value. In order to protect the assembled battery, a charger having a function of stopping charging is frequently used.
Among the thermistors, for example, a thermistor having a positive temperature characteristic (generally referred to as a PTC thermistor) has a characteristic that an impedance value increases with an increase in temperature. That is, the impedance value of the thermistor is low when the assembled battery is in a low temperature state, and the impedance value of the thermistor is high when the assembled battery is in a high temperature state compared to when the assembled battery is in a low temperature state. When such a thermistor is used, a charger for charging an assembled battery typically determines that the assembled battery is in a high temperature state when the voltage value at both ends of the thermistor is equal to or higher than a predetermined voltage value. Thus, a charger having a function of stopping charging is often used to protect the assembled battery.
Thus, the “assembled battery temperature index indicating that the assembled battery is in a high temperature state” may be an index that allows the charger side to determine that the assembled battery is in a high temperature state.

  By the way, in the assembled battery as described above, overcharge may occur in a predetermined unit battery due to variations in characteristics of individual unit batteries during charging. That is, even if the unit battery reaches full charge, if the charger that charges the assembled battery determines that the battery is not fully charged as an assembled battery, charging is continued and the unit battery is overcharged. May lead to charging. When such overcharge occurs, various problems such as deterioration of the unit battery occur.

  Therefore, as described in the above prior art, a technique using a battery monitoring circuit that outputs a voltage value of each unit battery is disclosed, but a configuration capable of stopping charging based on the voltage value of each unit battery In the battery charger not equipped with the above, even if the battery monitoring circuit outputs the voltage value described above, it cannot be used to prevent overcharging.

In the assembled battery monitoring device according to the present invention, in order to cope with such a problem, it is indicated that the assembled battery is in a high temperature state even when at least one voltage value is equal to or higher than a predetermined reference value when the assembled battery is charged. Outputs the battery temperature index.
Typically, when the assembled battery monitoring device uses the voltage value at both ends of the NTC thermistor as an assembled battery temperature index, the voltage value of each unit battery is monitored, and at least one is set in advance. If there is a unit battery that exceeds the reference value, the battery temperature index is output as if the impedance value of the thermistor has dropped. Thereby, on the charger side, it is possible to stop charging by determining that the temperature of the assembled battery is in a high temperature state. In this way, overcharging of the unit batteries constituting the assembled battery can be easily prevented on the side of the charger to which the assembled battery is connected. Moreover, in the assembled battery monitoring apparatus of this invention, the assembled battery temperature parameter | index output to the charger side is the case where charging of an assembled battery is stopped when an assembled battery is in a high temperature state, and even in one assembled battery. Since the unit battery having the voltage value equal to or higher than the reference value is used together with the case where charging of the assembled battery is stopped, the number of parts of the assembled battery monitoring device may be small. Thereby, an assembled battery monitoring apparatus can be comprised at low cost.

  Further, it is not necessary to provide a special configuration on the charger side for monitoring the voltage value of each unit battery and detecting whether there is any unit battery exceeding a preset reference value. Therefore, as described above, a charger having a configuration that can be stopped based on an assembled battery temperature index, as described above, and at least one of the configurations or the like without any particular design change. Charging can be easily stopped when the voltage values of the plurality of unit batteries are equal to or higher than a predetermined reference value.

  This assembled battery monitoring device suitably includes both an aspect accommodated in a battery pack together with the assembled battery, an aspect accommodated on the side of an operating device driven by using the assembled battery as a driving power source, and an independently configured aspect. .

(Invention of Claim 2)
According to the invention described in claim 2, in the assembled battery monitoring device according to claim 1, the assembled battery temperature index is output using an impedance circuit whose impedance value changes based on a temperature change of the assembled battery. .
The impedance circuit includes all elements, circuits, and the like that can change the impedance value by changing the temperature of the assembled battery and output at least that the assembled battery is in a high temperature state as an assembled battery temperature index.

In the invention according to claim 2, when the battery pack is charged, when the voltage value of at least one unit battery is equal to or higher than a predetermined reference value, the impedance value of the impedance circuit is that the battery pack is in a high temperature state. It is comprised so that it may change into the impedance value which shows.
Typically, the impedance circuit includes a first impedance circuit in which an impedance value is lowered based on a temperature change of the assembled battery, and a second impedance circuit in which the impedance value is fixed. The second impedance circuit is configured to output an assembled battery temperature index indicating that the assembled battery is in a high temperature state when the voltage value of at least one unit battery is equal to or higher than a predetermined reference value during charging. Are connected in parallel to the first impedance circuit.
The first impedance circuit is preferably a circuit using an NTC thermistor. The second impedance circuit is preferably an element or circuit having a substantially fixed impedance value without being influenced by the ambient temperature or the like, and is typically configured using a resistance element. Preferably, switching means such as a switch is provided in series with the resistance element. In this case, the second impedance circuit is wired in parallel with the thermistor, and the switch is normally in an open state (off state). When at least one voltage value is equal to or higher than a predetermined reference value, the switch is closed (on). As a result, the second impedance circuit is connected in parallel to the thermistor. That is, the impedance value of the “impedance circuit” of the present invention is the combined impedance value of the thermistor and the second impedance circuit (which is smaller than the impedance value of the thermistor alone). With this configuration, the assembled battery monitoring device outputs an assembled battery temperature index as if the impedance value of the thermistor has decreased when at least one voltage value is equal to or higher than a predetermined reference value when charging the assembled battery. To do.
Thus, the assembled battery monitoring device having the same effect as that of the first aspect of the invention can be obtained using a simple and low-cost circuit configuration.

(Invention of Claim 3)
According to a third aspect of the present invention, in the assembled battery monitoring device according to the first or second aspect, when the remaining capacity of the assembled battery is equal to or less than a predetermined reference value during discharging, an assembled battery remaining capacity lowering signal is output. Is configured to do.
The battery pack remaining capacity lowering signal is generally called an auto stop signal (AS signal). The auto-stop signal determines when the battery pack's remaining capacity has fallen below a predetermined value when the voltage value across the battery pack has dropped below a predetermined value or when the integrated value of the discharge current has exceeded a predetermined value. Is output. From the past, when the auto-stop signal is detected, the operating device that is driven by the assembled battery as the driving power source is often used to stop the operation of the operating device after saving the current settings and status of the operating device. Has been.
By the way, when the assembled battery is discharged, overdischarge may occur in a predetermined unit battery due to variations in characteristics of individual unit batteries. That is, even if the unit battery is used to the limit and reaches the discharge stop state, the discharge is continued unless the discharge stop state is reached as an assembled battery, and the unit battery may be overdischarged. When such overdischarge occurs, various problems such as deterioration of the unit battery occur.
Therefore, as described in the above prior art, a technique using a battery monitoring circuit that outputs a voltage value of a unit battery having the lowest voltage value is disclosed, but based on the voltage value of the unit battery having the lowest voltage value. For operating devices that do not have a configuration that can stop discharge (can stop the operation of the device), even if the battery monitoring circuit outputs the voltage value described above, it cannot be used to prevent overdischarge. It was.

Therefore, the assembled battery monitoring device according to the invention of claim 3 outputs an assembled battery remaining capacity lowering signal even when the voltage of at least one unit battery is equal to or lower than a predetermined reference value when the assembled battery is discharged. To do.
Typically, the assembled battery monitoring device monitors the voltage value of each unit battery, and if there is at least one unit battery that is equal to or lower than a preset reference value, it is as if the remaining capacity of the assembled battery is An assembled battery remaining capacity lowering signal is output as if it was below a predetermined reference value. Thus, in the present invention, at the time of discharging, the operating device driven with the assembled battery as a driving power source determines that the remaining capacity of the assembled battery is equal to or less than a predetermined reference value, and stops the operation. Can be stopped. In this way, overdischarge of the unit batteries constituting the assembled battery can be easily prevented on the side of the operating device driven using the assembled battery as a drive power source. And at the time of charge, there exists an effect similar to the invention of Claim 1 or 2.

(Invention of Claim 4)
According to the fourth aspect of the present invention, there is provided the assembled battery monitoring device that outputs an assembled battery remaining capacity lowering signal when the remaining capacity of the assembled battery configured by the rechargeable unit battery is equal to or less than a predetermined reference value. Composed.
Further, when the assembled battery is connected to an operating device capable of detecting a battery pack remaining capacity lowering signal and the operating device is driven using the assembled battery as a driving power source, the voltage of at least one unit battery of the assembled battery is The battery pack remaining capacity lowering signal is also output when the battery pack is below a predetermined reference value. Thereby, it is comprised so that the apparatus connected to the assembled battery can be stopped.

The operating device that can detect the battery pack remaining capacity drop signal typically has a CPU and operates when an auto stop signal (battery battery remaining capacity drop signal) output from the battery pack monitoring device is detected. It is configured as an operating device that can stop the operation after storing the current settings and status of the device.
In the present invention, at the time of discharging, when at least one voltage is equal to or lower than a predetermined reference value, the battery pack remaining capacity lowering signal is output as if the remaining capacity of the battery pack is equal to or lower than a predetermined reference value. As a result, in the present invention, on the operating device side that is driven by using the assembled battery as a driving power source, it is determined that the remaining capacity of the assembled battery is equal to or less than a predetermined reference value, and the operation is stopped. Stop. In this way, overdischarge of the unit batteries constituting the assembled battery can be easily prevented on the side of the operating device driven using the assembled battery as a drive power source. Further, in the battery pack monitoring device of the present invention, when the battery pack remaining capacity lowering signal output to the operating device side, when the battery pack remaining capacity is equal to or lower than a predetermined reference value, the discharge of the battery pack is stopped. Since there is at least one unit battery having a voltage value equal to or lower than the reference value in the assembled battery, the battery is used for stopping the discharge of the assembled battery, so the number of parts of the assembled battery monitoring device may be small. . Thereby, an assembled battery monitoring apparatus can be comprised at low cost.

  Further, it is not necessary to provide a special configuration on the operating device side for monitoring the voltage value of each unit battery and detecting whether there is any unit battery that is equal to or less than a preset reference value. Therefore, as mentioned above, it is an operating device with a configuration that can stop the discharge of the battery pack by stopping the operation based on the battery pack remaining capacity lowering signal that has been widely used in the past. Without changing, the discharge of the assembled battery can be easily stopped when the voltage value of at least one or a plurality of unit batteries is equal to or lower than a predetermined reference value.

(Invention of Claim 5)
The invention according to claim 5 is configured as a battery pack including an assembled battery constituted by a rechargeable unit battery and the assembled battery monitoring device according to any one of claims 1 to 4.
The “battery pack” typically discharges the assembled battery by connecting a circuit configuration for charging the assembled battery using an external device such as an assembled battery or a charger, or an operating device such as an electric tool (that is, the assembled battery). It has a circuit configuration that consumes a battery. In addition, the “battery pack” preferably includes a housing that accommodates the assembled battery and a printed circuit board on which the circuit configuration and a connection terminal that can be connected to a corresponding terminal of the charger or the operating device are mounted. It is configured to be attachable to and detachable from a charger or operating device.
And the battery pack of this invention is further provided with the assembled battery monitoring apparatus in any one of Claims 1-4 mentioned above.
Thereby, the battery pack which has the same effect as the invention according to claims 1 to 4 is obtained.

  (Invention of Claim 6)
  According to a sixth aspect of the present invention, there is provided an electric tool to which a battery pack including a plurality of rechargeable unit batteries and the assembled battery monitoring device according to any one of the first to fourth aspects is mounted. Configured as
  Thereby, the electric tool which has an effect similar to the invention of Claims 1-4 is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which contributes to dealing easily with the overcharge and overdischarge of the unit battery which comprise an assembled battery by the apparatus side which connects an assembled battery was provided.

  Hereinafter, an example of the best mode for carrying out the present invention will be described with reference to the drawings. In the present embodiment, as an example, a case where an assembled battery monitoring device is provided in a battery pack having an assembled battery in which rechargeable unit batteries are connected in series will be described. The configuration of the battery pack 100 according to the present embodiment is schematically shown in the block diagrams of FIGS. In FIG. 1, the structure of an example of the charger 200 which charges the battery pack 100 is also shown. FIG. 2 also shows a part of the configuration of an operating device 300 such as an electric tool that is used by connecting the battery pack 100.

First, the configuration of the battery pack 100 will be described with reference to FIG.
In the battery pack 100, the assembled battery 110 is discharged when the assembled battery 110 is connected to the circuit configuration in which the assembled battery is charged using an external device such as the charger 200 and the operating device 300 (that is, the battery pack 100 is discharged). A circuit configuration in which the assembled battery 110 is consumed) and a printed circuit board on which terminals TE1 to TE5 that can be connected to corresponding terminals of the charger 200 and the operating device 300 are mounted. Although not shown, the battery pack 100 includes a housing that accommodates the assembled battery 110 and the printed board, and is configured to be detachable from the charger 200 and the operating device 300.
When the battery pack 100 is attached to the charger 200, each terminal of the battery pack 100 is connected to each terminal of the corresponding charger 200, and the assembled battery 110 can be charged using the charger 200. .

As an assembled battery housed in the casing of the battery pack 100 described above, an assembled battery 110 in which unit batteries are connected in series is provided. In addition, various circuit configurations mounted on the printed circuit board include a battery control unit 130 that has a CPU and detects the voltage of each unit battery that constitutes the assembled battery 110, a charge control program that charges the assembled battery 110, parameters, and the like. The stored ROM 140, the NTC type thermistor TM whose main body is arranged in the vicinity of the assembled battery 110, terminals TE1 to 5 connected to corresponding terminals of the charger 200 and the operating device 300, and the battery control unit 130 are switched. A switch SW and a resistor R1 connected in series to the switch SW are provided.
The assembled battery 110 is an element corresponding to the “assembled battery” in the present invention.

The plus side (the upper side shown in FIGS. 1 and 2) of the assembled battery 110 is the terminal TE1 of the battery pack 100, and the minus side (the lower side shown in FIGS. 1 and 2) of the assembled battery 110 is the terminal of the battery pack 100. Connected to TE2.
Thereby, when the battery pack 100 is attached to the charger 200, the terminals TE1 and TE2 are connected to terminals TE11 and TE12 of the charger 200 described later, respectively, and the assembled battery 110 is charged.

Further, the minus side of the assembled battery 110 is connected to one end of the thermistor TM, and the other end of the thermistor TM is connected to the terminal TE4. The main body of the thermistor TM is disposed in the vicinity of the assembled battery 110, and the impedance of the thermistor TM decreases when the temperature of the assembled battery 110 rises. As a result, when the battery pack 100 is mounted on the charger 200 and the terminal TE4 is connected to the terminal TE14 of the charger 200, the temperature detection unit 250 of the control unit 230 of the charger 200 described later is transferred from the thermistor TM to the battery pack. The signal output from the thermistor TM is received via the terminal TE4 of 100 and the terminal TE14 of the charger 200. The voltage value across the thermistor TM (potential difference between the terminals TE4 and TE2) has a characteristic that it becomes smaller as the temperature of the assembled battery 110 rises and the impedance of the thermistor TM becomes lower. The temperature detection unit 250 of 200 can calculate the temperature of the assembled battery 110.
The potential difference between the terminals TE4 and TE2 is an element corresponding to the “assembled battery temperature index” of the present invention.

  The ROM 140 is connected to the terminal TE5. When the battery pack 100 is attached to the charger 200, the terminal TE5 is connected to a terminal TE15 of the charger 200 described later. The control unit 230 of the charger 200 described later can read the charge control program of the battery pack 100 and the specific parameters of the battery pack 100 stored in advance in the ROM 140 from the ROM 140 via the terminals TE5 and TE15.

A circuit 120 in which the switch SW and the resistor R1 are connected in series is wired in parallel with the thermistor TM. The switch SW of the circuit 120 is controlled to be opened and closed by the battery control unit 130. As a result, when the switch SW is in the open state (off state), an output signal based only on the impedance of the thermistor TM is output to the temperature detection unit 250 of the charger 200 via the terminals TE4 and TE14, and the switch SW is in the closed state. In the ON state, the resistor R1 is connected in parallel to the thermistor TM, and an output signal based on the combined impedance of the resistor R1 and the thermistor TM is output to the temperature detection unit 250 of the charger 200 described later via the terminals TE4 and TE14. Is done.
The thermistor TM and the circuit 120 in which the switch SW and the resistor R1 are connected in series are elements corresponding to the “impedance circuit” in the present invention.

The ground terminal G of the battery control unit 130 is connected to the terminal TE2. Accordingly, the terminal TE2, the ground terminal G of the battery control unit 130, one end of the circuit 120 described above, one end of the thermistor TM, and the minus side of the assembled battery 110 are connected.
The power supply terminal V of the battery control unit 130 is connected to the terminal TE1. Thereby, terminal TE1, the power supply terminal V of the battery control part 130, and the plus side of the assembled battery 110 are connected.
Further, a signal output terminal 131 (to be described later) of the battery control unit 130 is connected to the terminal TE3, but is not used when charging, that is, when connected to the charger 200, so the terminal TE3 is open.
Further, the battery control unit 130 is connected to each unit battery so that the voltage of each unit battery can be detected.
In addition, the battery control unit 130 has a CPU and a storage unit that are not particularly illustrated, and the storage unit has a case where the voltage of each unit battery of the assembled battery 110 is equal to or higher than a predetermined reference value in advance. A program or the like is stored that executes a procedure for opening the switch SW when the switch SW is in a closed state and when the switch SW is less than a predetermined reference value. The CPU reads and executes the program from the storage unit at an appropriate timing.
The assembled battery monitoring device 10 includes a battery control unit 130, a thermistor TM, a circuit 120 wired so as to be connected in parallel to the thermistor TM, a connection between the battery control unit 130 and the assembled battery 110 and each terminal, and the thermistor TM and circuit. It is comprised by the connection with 120, the assembled battery 110, and each terminal, and this structure is an element corresponding to the "assembled battery monitoring apparatus" of this invention.

Next, the outline of the configuration of the charger 200 that charges the battery pack 100 will be described with reference to FIG.
The charger 200 includes a power supply circuit 210 that converts AC input power into a DC power supply for charging the battery pack 100, a charge control unit 220 that controls the power supply circuit 210, a control unit 230 that controls the operation of the charger 200, and the charger 200. Is connected to a storage unit 240 in which parameters and the like for performing a charging operation (according to a model of the charger 200), terminals TE11, 12, 14, and 15 for connection with the battery pack 100, and an AC input power source are connected. Input terminals SE11 and SE12 are provided. The control unit 230 includes a temperature detection unit 250. Of course, the temperature detection unit 250 may be configured independently of the control unit 230.

  The input side of the power supply circuit 210 is connected to input terminals SE11 and SE12 to which an AC input power supply can be connected. The output side of the power supply circuit 210 is connected to output terminals TE11 and TE12 of a DC power supply that is converted from an AC input power supply by the power supply circuit 210 and charges the battery pack 100. In the charger 200 shown in FIG. 1, the output terminal TE11 is a power supply terminal, and the output terminal TE12 is a ground terminal. Further, although not shown, the power supply circuit 210 outputs a control power supply converted from an AC input power supply by the power supply circuit 210. This control power supply is supplied to an IC or the like in the charger 200. A storage unit 240, a power supply terminal TE11, a terminal TE15, and a charge control unit 220 are connected to the control unit 230. Further, a terminal TE14 is connected to the temperature detection unit 250 of the control unit 230.

Next, a general operation for charging the battery pack 100 (that is, the assembled battery 110) with the charger 200 will be described.
First, an AC input power source is connected to the input terminals SE11 and SE12 of the charger 200. As a result, the control power source in which the AC input power source is converted by the power source circuit 210 is supplied to the control unit 230, the charge control unit 220, the storage unit 240, and the temperature detection unit 250 in the charger 200, and the charger 200 operates. To start.
The battery pack 100 is attached to the charger 200, and the terminals TE1112, 14, and 15 of the charger 200 are connected to the terminals TE1, 2, 4, and 5 of the battery pack 100, respectively. At this time, the switch SW of the battery pack 100 is set to an open state as an initial state.

Further, as described above, the control unit 230 of the charger 200 reads the charge control program stored in the ROM 140 of the battery pack 100 and the specific parameters of the battery pack 100 via the terminals TE5 and TE15. The control unit 230 calculates a suitable charging current value at the start of charging of the battery pack 100 using the charging control program read from the ROM 140 and information such as parameters, and instructs the charging control unit 220 of the charging current value. Output a signal. The charging control unit 220 controls the power supply circuit 210 to output the charging current value based on the signal output from the control unit 230. In this way, charging of the assembled battery 110 of the battery pack 100 is started.
The control unit 230 monitors the charging current value using a shunt resistor connected to the ground terminal TE12, although not particularly illustrated, and when the charging current value becomes a set value or less, It is determined that charging of the assembled battery 110 is completed, and the charging operation is terminated.

  Further, during the charging operation, the temperature detection unit 250 of the control unit 230 is connected to the terminal TE4 (that is, the terminal TE14) and the terminal 2 based on the temperature characteristic that the impedance value decreases as the temperature of the thermistor TM increases. That is, it is monitored from the potential difference between the terminals TE12 that the temperature of the assembled battery 110 arranged in the vicinity of the thermistor TM is lower than the set temperature. When the controller 230 detects that the temperature of the assembled battery 110 is equal to or higher than the set temperature, the controller 230 outputs a signal for stopping the charging operation to the charging controller 220. Thereby, the malfunction by the temperature rise of an assembled battery can be prevented.

Here, the battery control unit 130 of the present embodiment monitors the voltage of each unit battery constituting the assembled battery 110 and determines that the voltage value of at least one unit battery is equal to or higher than a predetermined value. The switch SW of the circuit 120 is closed. Thereby, the resistor R1 is connected in parallel to the thermistor TM. If the impedance value of the thermistor TM at this time is Ztm (Ztm> 0) and the impedance value of the resistor R1 is R1 (R1> 0), the combined impedance Z of the parallel circuit of the thermistor TM and the circuit 120 is
Z = R1 · Ztm / (R1 + Ztm)
It becomes.
Here, in the temperature detection unit 250 of the charger 200, a temperature threshold value for determining that the assembled battery 110 is in a high temperature state is Ts, and an impedance value threshold value corresponding to the temperature threshold value Ts is Zs. For the combined impedance Z of the parallel circuit of the thermistor TM and the circuit 120 described above, the resistor R1 is always selected so that the following relational expression always holds regardless of how the impedance value Ztm of the thermistor TM changes during the charging period. , Used in the circuit 120.
Z <Zs
By selecting the resistor R1 in this way, the combined impedance value Z is always smaller than the impedance value threshold Zs if the switch SW of the circuit 120 is closed throughout the charging period. Then, the potential difference between the terminals TE4 and TE2 of the battery pack 100 decreases to a potential difference that allows the temperature detection unit 250 to determine that the assembled battery 110 is in a high temperature state.

Thus, when it is determined that the voltage value of at least one or a plurality of unit batteries among the unit batteries constituting the assembled battery 110 is greater than or equal to a predetermined value, the assembled battery monitoring device 10 of the battery pack 100 is An assembled battery temperature index as if the assembled battery 110 has reached a high temperature state is output to the charger 200 via the terminal TE4. The temperature detector 250 of the charger 200 calculates the temperature of the assembled battery 110 based on the potential difference between the terminals TE4 and TE2 of the battery pack 100, and sends a signal indicating that the assembled battery 110 is in a high temperature state to the controller 230. Output.
Based on this, the control unit 230 stops the charging operation.

Next, a general operation when the battery pack 100 (that is, the assembled battery 110) is used in the operating device 300 will be described with reference to FIG. In addition, the operating device 300 has an auto-stop function capable of stopping the operation after saving the current settings and conditions when an auto-stop signal is input from the battery pack 100.
As shown in FIG. 2, when the battery pack 100 is attached to the operating device 300, the terminals TE <b> 1 to TE <b> 3 of the battery pack 100 are connected to the corresponding terminals TS <b> 1 to TS <b> 3. 300 can be supplied with power.
By connecting in this way, discharge of the assembled battery 110 to the operating device 300 can be started as described above.

The battery control unit 130 of the battery pack 100 monitors the remaining capacity of the assembled battery 110. When the remaining capacity falls below a predetermined value based on the operable lower limit value, an auto stop signal is output from the signal output terminal 131 of the battery control unit 130.
When the control unit 310 of the operating device 300 receives the auto-stop signal via the terminal TE3 of the battery pack 100 and the TS3 of the operating device 300, the current setting and status of the operating device 300 are stored, and the operating device 300 is then stored. Control to stop the driving motor M is performed.
This auto stop signal is an element corresponding to the “battery battery remaining capacity reduction signal” of the present invention, and the operating device 300 corresponds to the “device capable of detecting the battery pack remaining capacity reduction signal” of the present invention.

Here, the battery control unit 130 of the present embodiment also monitors the voltage value of each unit battery constituting the assembled battery 110, and when the voltage value of at least one unit battery is equal to or lower than a predetermined value. Also, an auto stop signal is output from the signal output terminal 131 of the battery control unit 130. This operation is executed by the CPU of the battery control unit 130 based on the program stored in advance in the storage unit of the battery control unit 130 described above.
Thus, even when the voltage value of at least one unit battery among the individual unit batteries constituting the assembled battery 110 is equal to or lower than a predetermined value, the control unit 310 of the operating device 300 allows the terminal TE3 of the battery pack 100, The automatic stop signal is received via TS3 of the operating device 300, and the motor M driving the operating device 300 is controlled to stop.

In this way, the battery control unit 130 is configured as if the assembled battery 110 is in a high temperature state when the voltage of at least one or a plurality of unit batteries is equal to or higher than a predetermined value at the time of charging shown in FIG. Outputs battery temperature index. Thereby, the charger 200 stops the charging operation to the battery pack 100, and overcharge is prevented.
Further, at the time of discharging shown in FIG. 2, when the voltage of at least one unit battery becomes equal to or lower than a predetermined value, the battery control unit 130 outputs an auto stop signal as if the remaining capacity of the assembled battery is equal to or lower than the predetermined value. . Thereby, the operating device 300 having the auto-stop function is stopped, and overdischarge is prevented.

In the present embodiment, the battery pack 100 having both of the above-described functions has been described, but of course, any one of the functions may be provided.
Moreover, the assembled battery monitoring apparatus 10 of this invention is applicable also to assembled batteries other than a battery pack.
Further, in the present embodiment, the case where the assembled battery monitoring device 10 of the present invention is incorporated in the battery pack 100 together with the assembled battery 110 has been described, but the assembled battery monitoring device 10 is configured independently of the battery pack 100. May be.
In the present embodiment, the case where the “impedance circuit” of the present invention is configured using an NTC thermistor has been described. However, the “impedance circuit” is another element that outputs a temperature index of a battery pack such as a PTC thermistor. You may be comprised using.

A block diagram of battery pack 100 according to the present embodiment is shown together with a block diagram of charger 200 that charges battery pack 100. A block diagram of battery pack 100 according to the present embodiment is shown together with a block diagram of operating device 300 to which battery pack 100 is connected.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Battery pack 110 Battery pack 130 Battery control part 200 Charger 300 Actuator SW Switch TM Thermistor

Claims (6)

  When charging an assembled battery composed of a plurality of rechargeable unit batteries, if the temperature of the assembled battery exceeds a predetermined reference value, an assembled battery temperature index indicating that the assembled battery is in a high temperature state is output. An assembled battery monitoring device,
  An assembled battery temperature indicating that the assembled battery is in a high temperature state even when the voltage value of at least one of the plurality of unit batteries is equal to or higher than a predetermined reference value when the assembled battery is charged. An assembled battery monitoring device configured to output an index.   The assembled battery monitoring device according to claim 1,
  Having an impedance circuit whose impedance value changes based on a temperature change of the assembled battery;
  When charging the assembled battery, when the voltage value of at least one unit battery of the plurality of unit batteries is equal to or higher than a predetermined reference value, the impedance value of the impedance circuit is in a high temperature state. An assembled battery monitoring device configured to change to an impedance value indicating that.   The assembled battery monitoring device according to claim 1 or 2,
  At the time of discharging the assembled battery, when the remaining capacity of the assembled battery is equal to or lower than a predetermined reference value, the battery pack remaining capacity lowering signal is output,
  When the battery pack is discharged, the battery pack remaining capacity lowering signal is also output when the voltage value of at least one of the plurality of unit batteries is equal to or lower than a predetermined reference value. Battery pack monitoring device.   An assembled battery monitoring device that outputs an assembled battery remaining capacity lowering signal when an assembled battery composed of a plurality of rechargeable unit batteries discharges when the remaining capacity of the assembled battery is equal to or less than a predetermined reference value. And
  When the battery pack is discharged, the battery pack remaining capacity reduction signal is output even when the voltage value of at least one of the plurality of unit batteries is equal to or lower than a predetermined reference value. Battery pack monitoring device.   A battery pack provided with the assembled battery comprised by the several unit battery which can be charged, and the assembled battery monitoring apparatus in any one of Claims 1-4.   An electric tool to which a battery pack including an assembled battery configured by a plurality of rechargeable unit batteries and the assembled battery monitoring device according to any one of claims 1 to 4 is mounted.